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Welcome address Dear Colleagues and Friends,
It is my great pleasure to invite you to attend the international symposium “Advances in
Cardiovascular Research: From genes and molecules to clinical applications”, which will
be held at Devín – Bratislava, Slovakia in the Hotel Hradná Brána (Castle Gate) close to the
ruins of Devin Castle.
The goal of the Symposium is to bring together renowned scientists; clinicians, physiologists,
morphologists, molecular cardiologists, geneticists and all those working in the field of
cardiovascular research, the field, which has become so important, challenging and
rewarding.
The programme of the Symposium includes keynote lectures on selected topics, free oral
communications and poster presentations. We promise to create an exciting, enjoyable and
friendly atmosphere, which will be multiplied by your participation.
The Symposium will provide an excellent opportunity for an exchange of experience and new
ideas and will contribute to our understanding of the complexity of signaling pathways and
processes leading to the heart hypertrophy and failure, to its adaptation to ischemia, hypoxia,
overload and related pathophysiological situations, as well as for presentation of some novel
approaches towards the management of cardiovascular diseases.
We hope that despite heavy scientific schedule, there will be enough space for fruitful and
stimulating discussions and chances to enjoy the beautiful natural environment and important
historical place at the confluence of the Danube and Moravia rivers.
We are looking forward to your participation in this meeting.
Jan Slezak
On behalf of the Organizing Committee
2
Organization and committees
Symposium is organized by
Institute for Heart Research SAS CEKVY SAS Slovak Academy of Sciences
Slovak Society of Cardiology Slovak League Heart to Heart
Slovak Physiological Society
Institute of Cardiovascular Scien Academy of Sciences and Arts
Under the au f the International Academy of Cardiovascular Sciences
OCAL ORGANIZING OMMITTEE
Jan Slezak (president of the meeting), Jan Styk (vice-president of the meeting), Tana Ravingerova (scientific secretary), Attila Ziegelhoffer, Narcis Tribulova, Jan Murin, Eva Goncalvesova, Andrej Dukat, Gabriel Kamensky, Valentin Both, Ludmila Okruhlicova, Monika Bartekova, Miroslav Ferko, Katarina Dlugosova, Jana Matejikova, Jana Mujkosova, Maria Zazrivcova
INTERNATIONAL ADVISORY BOARD Naranjan S. Dhalla, Lorrie Kirshenbaum, Grant N. Pierce, Dennis B. McNamara, Pawan K. Singal, Felix Unger CONTACTS Institute for Heart Research SAS Dúbravská cesta 9, P.O.B. 104, 840 05 Bratislava 45 Phone: 00421 2 54774405 Fax: 00421 2 54776637 E-mail: [email protected]; [email protected]
ces European
spices o
LC
3
General information
lovanske nabrezie 15, 84110 Bratislava – Dev
, S ntis Pharma Slovakia s. r. o., Roche .r.o., FISHER Slovakia, s.r.o.
EGISTRATION Congress materials and badges will be available at the registration desk:
September 28th 8.00 – 18.00 29th 8.00 – 12.30
ion to the Devin Castle er and Get together party
NSTRUCTION FOR PRESENTERS
e lecture hall. osters will be displayed on September 28th throughout the whole day. Authors should be
rs during the guided Poster session.
PROGRAM O
aturday, September 27th commodation
Sunday, Septeion II.
Lunch tle
Session III. Session IV.
Session VI. Closing Lunch/Farewell
SYMPOSIUM VENUE Hotel Hradná Brána (Castle Gate) S ín, Slovakia Phone: 00421-2-601 025 11 Fax: 00421-2-601 025 12 E-mail: [email protected] SPONSORS Bayer HealthCare, Bayer Schering PharmaSlovensko, s
anofi-Ave
R
September 27th 18.00 – 20.00
September SOCIAL PROGRAM Sunday, September 28th
Guided excursReception dinn
I Audio-visual equipment will be provided for PowerPoint presentations. Please, handle your presentation in advance to the attendant in thPpresent at their postePosters size: 85 cm width, 110 cm length.
VERVIEW
SArrival, ac
mber 28th Session I. Sess
Excursion to the Devin cas
Poster Session Reception dinner and Get together party
Monday, September 29th
Session V.
4
Scientific Programme
PTEMBER 27TH
and accommodation SATURDAY, SE
19.00. – 20.00 Arrival DAY, SEPTEMBER 28 SUNTH
8.45
Opening: Jan Slezak, Naranjan S. Dhalla
9.00 – 10.40 Session I. Diabetes, dyslipidemia, metabolic syndrom - from basic knowled
ge to the prospective pharmacological approaches
urin (Slovakia), Grant Pierce (Canada)
Rescue of diabetes related impairment of myocardial angiogenesis by gene
nada) he effect of trans fats on cardiovascular health
A) Insulin glargine, but not insulin glulisine, attenuates catheter-induced carotid
f IGF-1
of e metabolic syndrome
0.20 - 10.40 ana Ravingerova, Bratislava (Slovakia) o ed in yocardial response
Chairs: Jan M
9.00 - 9.20 Nilanjana Maulik, Farmington (USA)
therapy: potential and challenges 9.20 - 9.40 Grant Pierce, Winnipeg (Ca
T
0 - 10.00 Dennis B. McNamara, New Orleans (US9.4
intimal hyperplasia in Zucker fatty rats: Role o 10.00 - 10.20 Stephen W. Schaffer, Mobile (USA)
Contributions of lipids and diabetes in ischemic injury in a rat modelth
1 T
Changes in PPAR gene expression are inv lv mto ischemic injury in normal and diseased heart: relevance to pleiotropic effects of statins
10.40 – 11.10
Coffee break
11.10 – 12.30 Session II. Sympathetic nervous system and RAAS - known or yet unknown?
en (Canada)
ects
ical activities of heart
Chairs: Olga Pechanova (Slovakia), Frans H.H. Leen
11.10 - 11.30 Belma Turan, Ankara (Turkey)
Chronic treatments with beta-adrenergic blockers have differential effon electrical and mechan
11.30 - 11.50 Frans H.H. Leenen, Ottawa (Canada)
Brain mechanism contributing to sympathetic hyperactivity and heart
5
failure. Critical role for tissue RAAS
1.50 - 12.10 rivastava, Montreal (Canada) induced Gi signaling in hypertension
r Research Topics in the Health Priority Area 3rd Call of the th ent
13.40 - 15.40
adhu Anand-S1 M
Angiotensin II-
Let us work together - Networking Valentin Both, Bratislava (Slovakia) Cardiovascula
12.10 - 12.30
EU 7 Framework Programme for Research and Technology Developm
12.30 - 13.40 Lunch
Guided excursion to the Devin Castle
15.40 - 17.15 Session III. NO and cardiovascular protection kia), Andrzej Beresewicz (Poland)
ar mechanisms of vasculoprotective effect of NO
arrhythmias
ffect of Provinol on cardiac Na ,K -ATPase during hypertension
offee break
Chairs: Ludmila Okruhlicova (Slova 15.40 - 16.00 Philip J. Kadowitz, New Orleans (USA)
Nitrite therapy for CV disease 16.00 - 16.20 Olga Pechanova, Bratislava (Slovakia)
Peripheral and central regulation of blood pressure: the role of nitric oxide Ashok Srivastava, Montreal (Canada) 16.20 - 16.40Molecul
16.40 - 17.00 Agnes Vegh, Szeged (Hungary)
eroxynitrite-induced protection against P
17.00 - 17.15 Norbert Vrbjar, Bratislava (Slovakia) + +E
17.15 - 17.30 C 17.30 - 19.05 Session IV. Adaptative (protective?) mechanisms in
cardiovascular system
hairs: Tana Ravingerova (Slovakia), Agnes Vegh (Hungary) C
17.30 - 17.50 Michael P. Czubryt, Winnipeg (Canada)
he transcription factor scleraxis is a novel regulator of cardiac collagen Tsynthesis
arie Novakova, Brno (Czech Republic) 17.50 - 18.05
eptors in rat and mouse under
ttila Ziegelhoffer, Bratislava (Slovakia) rbonic anhydrase IX in hypoxic rat cardiomyocytes: role of
MExpression of the cardiac sigma recphysiological and various pathological conditions A18.05 - 18.20Induction of ca
6
the mitochondria
18.20 - 18.35 ava (Slovakia) protein, connexin-43, a key player or
y?
8.50 - 19.05 kruhlicova, Bratislava (Slovakia) orta of rats with different
Narcis Tribulova, Bratisl
myocardial gap junction channel Isbystander in modulation of cardiac lethal arrhythmia susceptibilit
18.35 - 18.50 Amarjit S. Arneja, Winnipeg (Canada)
How perıpheral arterial disease may predict coronary artery events
udmila O1 LVariability of connexin-43 expression in the agenotype
19.05 - 20.00 Poster Session - guided
Chairs: Narcis Tr ibulova (Slovakia), Zoltan Papp (Hungary) - Part I. arie Novakova (Czech Republic), Grant Pierce (Canada) – Part II.
20.00 - 23.00
M
Reception dinner and Get together party
TH
MONDAY, SEPTEMBER 29
9.00 – 10.50 Session V. New aspects of heart failure
9.00 - 9.20 awan K. Singal, Winnipeg (Canada) ) imbalance in heart failure
.20 - 9.40
ngestive heart failure
o be On TARGET - aimed on better cardiovascular prevention:
0 lvesova, Bratislava (Slovakia)
5
Chairs: Jan Styk (Slovakia), Pawan K. Singal (Canada)
PCytokine (TNF-α and IL-10
9 Jan Murin, Gabriel Kamensky, Bratislava (Slovakia)
Renal dysfunction and heart failure 9.40 - 10.00 Naranjan S. Dhalla, Winnipeg (Canada)
echanisms of subcellular remodeling in coM
10.00 - 10.20 Zoltan Papp, Debrecen (Hungary) Altered contractile protein phosphorylation during heart failure
10.20 - 10.35 Andrej Dukat, Bratislava (Slovakia)
TONTARGET results
10.35 - 10.5 Milan Luknar, Peter Lesny, Eva Gonca
BNP in acute heart failure 10.50 - 11.0 Coffee break
7
11.05 - 12.30: Session VI. Mechanisms of cell death and survival
hairs: Attila Ziegelhoffer (Slovakia), Naranjan S. Dhalla (Canada)
11.05 - 11.25 ypoxia-induced disruption of Rb/E2F-1 inhibitory complexes provokes
tricular myocytes 11.25 - 11.45 Warsaw (Poland)
ost-ischemic endothelial injury and its protection by ischemic
1.45 - 12.05 ipak K. Das, Farmington (USA)
ptation and autophagy - a cry for survival
diac myocytes to hronic ischemia and return to functional myocardium
losing remarks: Jan Slezak, Pawan K. Singal
12.30
C
Lorrie A. Kirshenbaum, Winnipeg (Canada) HBnip3 gene expression and cell death of ven Andrzej Beresewicz,Ppreconditioning
1 DMyocardial ada
12.05 - 12.20 Jan Slezak, Bratislava (Slovakia)
Hibernating myocardium: Adaptation remodeling of carc
C
Lunch / Farewell
8
Poster Session
ist of Poster presentations
art I.
1. Barbara Bacova, Katarina Dlugosova1, Miroslav Barancik1, Ludmila Okruhlicova1, Narcis Tribulova1, Bratislava (Slovakia) Omega-3 fatty acids attenuate down-regulation of myocardial connexin-43 in spontaneously hypertensive and hereditary hypetriglyceridemic rats
2. Monika Bartekova1, Dezider Pancza1, Olga Krizanova2, Albert Breier2, Jan Styk1, Tana Ravingerova1, Bratislava (Slovakia) The effect of quercetin on ischemia/reperfusion injury in isolated rat heart
3. Katarina Dlugosova1, Marcela Mitasíkova1, Ruzena Sotnikova2, Iveta Bernatova3, Peter
Weismann4, Narcisa Tribulova1, Jan Slezak1, Ludmila Okruhlicova1, Bratislava (Slovakia) 3-omega polyunsaturated fatty acids-treatment increases connexin43 expression in aorta of aged SHR
4. Miroslav Ferko1, Jana Mujkosová1, Tereza Holotnakova2, Dana Kincelova3, Iveta Waczulíkova3, Olga Pechanova4, Olga Ulicna5, Tana Ravingerova1, Attila Ziegelhöffer1, Bratislava (Slovakia) Endogenous protective mechanisms in acute diabetic rat heart: Different involvement of free radicals
5. Eva Goncalvesova1, Jan Lakota2, Viliam Fridrich1, Pavol Povinec3, Milan Luknar1, Juraj
Fabian1, Bratislava (Slovakia) Feasibility and safety of intracoronary injection of mesenchymal stem cells in severe ischemic cardiomyopathy. Immediate, intermediate, and long-term follow-up
6. Veronika Javorkova1, Jana Vlkovicova1, Lucia Mezesova1, Olga Pechanova2, Norbert
Vrbjar1, Bratislava (Slovakia) Sexual dimorphism in functional properties of cardiac Na,K-ATPase in SHR
Part II. 7. Lucia Kolenova, Katarina Dlugosova1, Vladimir Knezl2, Peter Weismann3, Ludmila
Okruhlicova1, Jan Jakubovsky, Narcis Tribulova1, Bratislava (Slovakia) Atorvastatin and omega-3 fatty acids decrease susceptbility of hypertriglyceridemic rat heart to lethal arrhythmias. Connexin-43 implication
8. Vladimir Knezl, Jan Drimal, Marcela Mitasikova1, Peter Weismann2, Narcis Tribulova1,
Bratislava (Slovakia) Sex differences in the incidence of lethal arrhythmias correlate with myocardial connexin-43 expression disparaties
L P
9. Jana Matejikova1, Jarmila Kuchar 2 3 Frantisek Kolar3, Dezider Pancza1, Tana Ravingerova1, Bratislava (SlProtection against ischemia-induced arrhythmias in the diabetic heart does not require
signaling: relevance to ischemic preconditioning
a Mujkosova1, Michal Cagalinec2, Miroslav Ferko1, Olga Ulicna3, Iveta aczulikova2, Dana Kincelova2, Tana Ravingerova1, Attila Ziegelhőffer1, Bratislava
11. rnatova, Bratislava
1 1 1 2
13.
ska , Jan Neckar , ovakia)
PI3K/Akt activation and ROS 10. Jan
W(Slovakia) Calcium signaling to rat heart mitochondria in acute diabetes: a measure for salvage of cardiac energetics
ozef Torok, Angelika Puzserova, Anna Zemancikova, Iveta BeJ(Slovakia) Effect of chronıc socıal stress on blood pressure and neurogenıc contractıons of mesenterıc artery ın rats wıth genetıc hypertensıon
12. Jana Vlkovicova , Veronika Javorkova , Lucia Mezesova , Olga Pechanova , Norbert Vrbjar1, Bratislava (Slovakia) Regularion of cardiac Na,K-ATPase by nitric oxide during hypertension Maria Zazrivcova1, Adriana Adameova2, Dezider Pancza1, Ján Styk1, Tana
avingerova1, Bratislava (Slovakia) RProtective effects of treatment with simvastatin against ischemia/ reperfusion injury in isolated rat heart
10
ABSTRACTS OF ORAL COMMUNICATIONS Session I. Diabetes, dyslipidemia, metabolic syndrom - from basic knowledge to t he p
rospective pharmacological approaches
11
RESCUE OF DIABETES RELATED IMPAIRMENT OF MYOCARDIAL NGIOGENESIS BY GENE THERAPY: POTENTIAL AND CHALLENGES
ry, Department of Surgery, University of onnecticut Medical School, Farmington, Connecticut-06030, USA
he last few decades have seen significant advancement in the knowledge of the molecular
echanism of angiogenesis and how it can be modulated to treat pathological conditions such
s cancer and ischemic heart diseases. When an oncologist is interested to inhibit
ngiogenesis and thereby curb tumor growth and metastasis, a cardiologist would aim at
ducing angiogenesis to rejuvenate the failing heart. Therapeutic angiogenesis makes use of
e angiogenic potential of a drug or growth factor (protein or gene) to promote the
evelopment of endogenous collateral vessels in the ischemic myocardium. However, therapy
sing recombinant vectors encoding a single angiogenic growth factor (Vascular Endothelial
rowth Factor/VEGF and Angiopoietin-1/Ang1) has shown less significant improvement
an what was expected, mainly because the biological system requires a cascade of growth
ctors, their receptors, and responsive intracellular signaling mechanisms for the
evelopment of a fully functional vascular system. Therefore, therapeutic angiogenesis is
urrently targeting combinations of angiogenic molecules as a measure to induce myocardial
ngiogenesis. A strategy to locally overexpress VEGF and Ang-1 in combination would prove
be beneficial because while VEGF can take the lead in the process of neovascualrization,
ng-1 would be expected to support the maturation of the newly formed vessels. A number of
tudies in rabbit, rat and mice models of hind limb or myocardial ischemia, have
emonstrated the efficacy of coexpressing VEGF and Ang-1 in inducing revascularization
nd improving vascular perfusion when compared to overexpressing either one of these
rowth factors. However, pathological conditions such diabetes reflects a far more
hallenging condition, where the angiogenic system (VEGF and Ang1) is significantly
ownregulated thereby hampering the hearts ability to respond to an ischemic stress.
herefore supporting the overexpression of these angiogenic factors by means of gene therapy
ould be expected to correct the process of impaired angiogenesis in the diabetic ischemic
yocardium. These astounding possibilities paved the way for the induction of angiogenesis
y intramyocardial co-administration of adenovirus encoding VEGF and Ang1 in the diabetic
chemic heart. Our results have documented that intramyocardial administration of vectors
ncoding VEGF and Ang1 in combination significantly reduced infarct size and myocardial
brosis in the diabetic ischemic heart when compared to the Ad-LacZ treated diabetic control.
A Nilanjana Maulik
olecular Angiogenesis and Cardiology LaboratoMC T
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12
THE EFFECT OF TRANS FATS ON CARDIOVASCULAR HEALTH Grant N. Pierce, Chantal M.C. Dupasquier, Andrea L. Edel, David Blackwood, Thane
lanie N. Richard and Elena Dibrov.
University of Manitoba, innipeg, Canada
G. Maddaford, MeCanadian Centre for Agri-food Research in Health and Medicine, St Boniface Hospital Research Centre, Department of Physiology, Faculty of Medicine,W Epidemiological studies have shown that ingestion of trans fatty acids in the diet are
associated with a high incidence of cardiovascular disease. Because of this, many countries
have legislated against the inclusion of trans fats in foods. This legislation and the data on the
deleterious effects of trans fats have important implications for a variety of dietary areas
including the dairy industry. Many dairy products naturally contain significant quantities of
trans fats and it is possible that the deleterious effects of trans fats may have a large
detrimental impact upon the dairy industry as a whole. It is surprising, therefore, in view of
these data and such governmental intervention, that the mechanism whereby trans fats
generate cardiovascular complications has not been identified. It has been assumed that trans
fats contribute to atherogenesis but the few studies that have tested this hypothesis have
produced negative results. As well, it is possible that the trans fat found in dairy products
(vaccenic acid) may have different effects on the cardiovascular system than the hydrogenated
trans fat primarily ingested (elaidic acid). The talk will present our latest data demonstrating
that dietary trans fat will, under selected conditions, induce atherosclerosis in an excellent
animal model of coronary heart disease. We will also discuss our recent findings that dietary
supplementation with the trans fats elaidic acid and vaccenic acid will produce very different
effects on atherogenesis. Our data provide mechanistic information on the cardiovascular
action of trans fats and this has an impact upon not only our health but the food industry as
well.
13
INSULIN GLARGINE REDUCES CAROTID INTIMAL HYPERPLASIA AFTER ALLOON CATHETER INJURY IN ZUCKER FATTY RATS POSSIBLY BY IGF-1
ealth Sciences Center, New Orleans, LA 70112
lloon catheter injury in obese non diabetic animals. These
nd are associated with an increase in serum
ular oxidative stress.
BMEDIATED REDUCTION IN OXIDATIVE STRESS Dennis B. McNamara, Subramanyam N. Murthy, Philip J. Kadowitz and Vivian Fonseca Tulane University H
OBJECTIVE: To test the effect of short acting (glulisine) and long acting (glargine) insulin
on vascular intimal hyperplasia in the carotid artery following balloon catheter injury in
Zucker fatty rat.
RESEARCH DESIGN AND METHODS: Non diabetic Zucker fatty rats were injected 0.45
mg/kg of glargine (once) or glulisine (twice) daily for 1 week before and 3 weeks after
balloon injury and then sacrificed. Sections of the carotid artery were used for measuring
intima/media ratio, in a blinded manner. Sections were stained for nitrotyrosine and 8-
isoprostane was assayed in the aortic arch protein. Glucose and IGF-1 were measured in
blood.
RESULTS–: Compared to controls carotid intima/media ratio was significantly reduced only
in the glargine treated animals [0. 9 ± 0.1-control; 0.6 ± 0.1-glulisine; 0.4 ± 0.1-glargine,
p<0.05]. The serum IGF-1 levels were significantly higher in glargine treated rats [567 ± 121
(ng/ml)-control; 1059 ± 150(ng/ml)-glargine]. The aortic 8-isoprostane levels were decreased
significantly in the glargine treated rats [(921 vs. 2566 pg/mg protein; p<0.05]. Intensity of
nitrotyrosine staining was significantly lower in both the insulin treated animals compared to
control; being lowest level in the glargine treated animals. Fasting and post –prandial glucose
was unchanged.
CONCLUSION–: We conclude that insulin glargine (or to a lesser extent glulisine) attenuates
intimal hyperplasia following ba
effects are independent of changes in glucose a
IGF -1 and decreased vasc
14
CONTRIBUTIONS OF LIPIDS AND DIABETES IN ISCHEMIC INJURY IN A RAT MODEL OF THE METABOLIC SYNDROME
1 2 Stephen W. Schaffer and Mahmood Mozaffari
ollege of Georgia, Oral Biology and Maxillofacial Pathology, Augusta, GA, USA
arts obtained from glucose intolerant, borderline type 2 diabetic rats are resistant to
re was induced in glucose intolerant and control rats by performing a
.
group although they were reduced in the glucose intolerant, hypertensive
rential that existed between the hypertensive
nd hypertensive, glucose intolerant rats. In conclusion, fat feeding and elevations in
usion pressure increase the susceptibility of the glucose intolerant heart to
ia/reperfusion. These findings are relevant to the metabolic syndrome that manifests
sistance, dyslipidemia and systemic hypertension.
1University of South Alabama, Pharmacology, School of Medicine, Mobile, AL, USA and 2Medical C
He
ischemia, an effect attributed to elevations in protein kinase C and reduction in [Ca2+]i during
the ischemia/reperfusion insult. To examine the effect of hypertension on ischemic injury,
high blood pressu
uninephrectomy procedure and feeding the animals a high salt diet. Surprisingly, infarct size
was reduced in the salt sensitive hypertensive animals, with the reduction in infarct size
greatest in the glucose intolerant, hypertensive animals. However, an elevation in perfusion
pressure prevented the beneficial effects of hypertension on infarct size, although infarct size
was still reduced in the hypertensive, glucose intolerant rats despite the elevation in perfusion
pressure
Another factor that influences infarct size is fat feeding, although the response differs
in the glucose intolerant and tolerant rats. Over an 18 week period, fat feeding had no effect
on plasma insulin and leptin levels of the hypertensive, glucose intolerant rat, but resulted in
an increase in plasma triglyceride levels, a rise in the degree of glucose intolerance and a
decline in contractile function. By contrast, chronic fat feeding led to elevations in body
weight, plasma leptin content and the degree of insulin resistance of the hypertensive rat.
Rates of contraction (+dP/dt) and relaxation (-dP/dt) were largely unaffected by fat feeding in
the hypertensive
group. Initiation of regional ischemia led to a severe reduction in contractile function in both
groups, with the contractile defect worsening during the ischemic period. While fat feeding
did not affect infarct size of the hypertensive rat, it worsened that of the hypertensive, glucose
intolerant rat, causing the abrogation in the diffe
a
perf
ischem
as a cluster of insulin re
15
CHANGES IN PPAR GENE EXPRESSION ARE INVOLVED IN MYOCARDIAL RESPONSE TO ISCHEMIC INJURY IN NORMAL AND DISEASED HEART:
ELEVANCE TO PLEIOTROPIC EFFECTS OF STATINS
1Inst Heart Res, Slovak Acad Sci & CEKVY SAS; Dept Pharmacol and Toxicol, Fac Pharm, 3
of CH. In the present study we characterized the effect of treatment with S (10
mg/kg/
c target in the
anagement of ischemic heart disease. Supported by Grants VEGA SR 2/0173/08, 1/4296/07
R Tana Ravingerova1, Adriana Adameova2, Tara Kelly3, Maria Zazrivcova1, Dezider Pancza1, Antigone Lazou3
2
Comenius Univ, Bratislava, SR; Sch Biol, Aristotles Univ, Thessaloniki, Greece
Hypercholesterolemia (H-CH) has a negative impact on ischemia/reperfusion (I/R) injury,
while lowering of serum CH by statins is widely used in the treatment of coronary artery
disease. However, statins have additional CH-independent effects. One of these pleiotropic
actions includes regulation of peroxisome proliferator-activated receptors (PPARs), the key
transcriptional regulators of lipid metabolism and energy production involved in the
mechanisms of I/R injury. We have recently shown that H-CH reduced gene expression of
both, PPAR alpha and gamma isoforms post-I/R and exacerbated an outcome of I/R injury in
the diabetic hearts, while simvastatin (S) restored their tolerance to ischemia without affecting
high levels
day, p.o.) on myocardial infarction and ischemia- and reperfusion-induced ventricular
arrhytmias in the normocholesterolemic rat hearts, as well as on the cardiac gene expression
of PPAR alpha. Regional 30-min ischemia induced by occlusion of LAD coronary artery was
followed by 120-min reperfusion. The infarct size (IS; TTC staining) was expressed as a
percentage of area at risk (AR) size. Gene expression of PPAR alpha was measured in the left
ventricular tissue at baseline conditions and after I/R (RT-PCR). Following 5 days, mRNA
levels of PPAR alpha in the hearts of treated rats were increased by 78% as compared with
the non-treated controls. In the S-treated animals, IS/AR was significantly smaller (11.5 ±
0.4% vs. 33.7 ± 4% in C; P<0.05). During ischemia, the incidence of ventricular arrhythmias
was reduced in the treated group. In addition, treatment with S resulted in attenuation of
postischemic contractile dysfunction and lower severity of reperfusion-induced arrhythmias.
Enhanced resistance to I/R injury was associated with preservation of baseline mRNA levels
of PPAR after I/R in these hearts in contrast to their downregulation in the non-treated group
(post I/R reduction by 65%). In conclusion, changes in the expression of PPAR may
potentially account for cardioprotective effects of statins under conditions of
normocholesterolemia. PPAR might represent an important therapeuti
m
16
Session II. Sympathetic nervous system and RAAS - known or yet unknown?
17
CHRONI HAVE DIFFERENTIAL EFFECTS ON ELECTRICAL AND MECHANICAL ACTIVITIES
F HEART
elma Turan epartments of Biophysics, Pharmacology, Faculty of Medicine, Ankara University, Ankara, urkey
ardiovascular diseases are major causes of mortality in patient population and beta-
drenergic blockers are one of the most frequently prescribed cardiovascular drugs. Although
ere are significant differences among agents, their clinical effects are predictable. Since
ropranolol (PROP) and timolol (TIM) are nonselective agents with different beta-potency,
e wanted to examine the long-term effects of selective blocker, PROP (25 mg/kg/day) – or
IM (5 mg/kg/day) administrations (intragastrically), on hemodynamic and action potential
arameters, and Ca2+-release mechanisms of the rat hearts. Maturation-induced depressions in
ft ventricular developed pressure (LVDP; 30-50%)) were significantly restored with TIM
ut not PROP) treatment. In addition, markedly prolonged two late repolarization phases of
ction potential with maturation were normalized with TIM treatment. Maturation-induced
ignificant inhibition in L-type Ca2+-current and marked increase in intracellular basal Ca2+
vel were recovered completely with TIM treatment. In addition, a significant decrease in
e Ca2+ transients (obtained with electrical stimulation) was observed with maturation, and
is value was shown to decrease further after TIM treatment while it was completely
ormalized with the PROP treatment. As summary, present data suggest that TIM improved
ft ventricular function due to its beneficial effect on Ca2+-influx in maturation- and/or aging-
duced depressed cardiac function while PROP showed different effect. Therefore, our
sults suggest that although treatment with beta-adrenergic blockers appear to confirm the
le of adrenergic pathway in heart function of adult rats; there are differences in the effect of
dividual beta-adrenergic blocking agent when particular clinical benefits are addressed
107S427 and TUBITAK-COST-107S304).
C TREATMENTS WITH BETA-ADRENERGIC BLOCKERS
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(Supported by TUBITAK-SBAG-
18
BRAIN MECHANISMS CONTRIBUTING TO SYMPATHETIC HYPERACTIVITY AND HEART FAILURE: CRITICAL ROLE FOR TISSUE RAAS Frans HH Leenen
ttawa Heart Institute, Ottawa, Ontario Canada
ascular regulation has been emerging in recent
ral infusions of an
ldosterone synthase inhibitor, indicating that the MR activation in the CNS post MI depends
n aldosterone, locally produced.
n conclusion, beyond its classical role as a hormone regulating renal Na+-transport,
ldosterone exerts profound effects on arteries and the heart. Its central actions are recently
merging, and appear to play a crucial role in cardiovascular homeostasis, when challenged
y high salt intake, or decreased cardiac function.
eferences:
University of O
he major role of the brain RAAS in cardiovT
years. The presence of enzymes involved in steroidogenesis (including aldosterone synthase),
MR and 11β–HSD-2 has been well documented in several parts of the CNS including the
hypothalamus, and a functional role for locally in the CNS produced aldosterone is becoming
apparent. Sympatho-excitatory and hypertensive responses to central infusions of aldosterone
are MR mediated. MR activation by aldosterone appears to activate CNS pathways by
enhancing ENaC activity followed by “ouabain” release and AT1-receptor stimulation. These
CNS mechanisms are activated by central infusions of Na+-rich aCSF and by high salt intake
in Dahl S and SHR. Most of the MR activation appears to be due to an increase in locally
produced aldosterone. Interestingly, the CNS pathways mediating sympathetic hyperactivity
in rats with CHF post MI involve the same mechanisms, ie MR activation via ENaC increases
central “ouabain” release and AT1-receptor stimulation. Studies with transgenic rats with
absent glia angiotensinogen demonstrated that the latter involves locally in the CNS produced
Ang II. The actual CNS pathways involve AT1-receptor stimulation in the PVN, but the
proximal part has not yet been clarified. It is possible that an increase in circulating Ang II
post MI leads to chronic activation of neurons in circumventricular organs such as the SFO
and to activation of this neuromodulatory pathway acting as an amplifier. MR activation in
the CNS not only contributes to the sympathetic hyperactivity, but also to activation of
several other peripheral systems such as the circulatory and cardiac RAAS as well as well the
increase in circulating cytokines. Not surprisingly, these central pathways also play a major
role in disease progression post MI. Chronic central infusion of a MR blocker prevents a
major part of the structural remodeling of the heart post MI, as well as a major part of the
decrease in LV function. Similar results can be obtained by chronic cent
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1. Lal A, Veinot JP, Leenen FHH. Cardiovas Res 64:437-447, 2004.
. Wang H, Huang BS, Ganten D, Leenen FHH. Circ Res 94:843-849, 2 2004.
c Res (Editorial). 101:221-223, 2007
. Cardiovasc Res, 2008 (in
3. Leenen FHH. Cir
4. Huang B, White R, Ahmad M, Tan J, Jeng AY, Leenen FHH
press)
20
ANGIOTENSIN II- INDUCED Gi SIGNALING IN HYPERTENSION
ity of Montreal, Montreal, Quebec,
We have previously shown an enhanced expression of Giα proteins in spontaneously
ypertensive rats (SHR) that precedes the development of hypertension. Since the levels of
asoactive peptides including angiotensin II (Ang II) have been shown to be enhanced in
HR, the present studies were undertaken to examine the role of Ang II and associated
ignaling in enhanced expression of Giα proteins in SHR. Aortic vascular smooth muscle
ells (VSMC) from 12 week-old SHR and Wistar-Kyoto rats (WKY) were used for the
resent studies. VSMC from SHR exhibited enhanced expression of Giα-2 and Giα-3 proteins
s compared to age-matched WKY. The increased levels of Giα-2 and Giα-3 were restored
control WKY levels by captopril; angiotensin converting enzyme inhibitor, losartan; an
T1 receptor antagonist as well as PD 98059; a selective inhibitor of MAP kinase. The
vels of superoxide anion (O2-) that were increased in SHR were also restored to control
KY levels by losartan. Furthermore, treatment of VSMC with antioxidants such as N-
cetyl-L-cysteine (NAC) or diphenyleneiodonium (DPI) and PD 98059 reversed the enhanced
xpression of Giα-2 and Giα-3 proteins and enhanced ERK1/2 phosphorylation to control
vels. The growth factor receptor inhibitors such as the inhibitors of platelet-derived growth
ctor receptor (PDGFR), epidermal growth factor receptor (EGFR) and insulin like growth
ctor receptor (IGFR) were also able to restore the enhanced levels of Giα-2 and Giα-3
roteins and enhanced ERK1/2 phosphorylation to control levels. In addition, the
hosphorylation of PDGFR, EGFR and IGFR was enhanced in VSMC from SHR as
ompared to WKY which was restored to control levels by captopril. These results suggest
at enhanced levels of Giα in SHR may be attributed to Ang II-induced enhanced oxidative
tress which exerts its effects through growth factor receptor-mediated MAP kinase signaling
athway. (Supported by grant from CIHR).
Madhu B. Anand-Srivastava Department of Physiology, Faculty of Medicine, UniversCanada
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Session III. NO and cardiovascular protection
22
NITRITE THERA
hilip J. Kadowitz ew Orleans (USA)
PY FOR CV DISEASE
PN
23
PERIPHERAL AND CENTRAL REGULATION OF BLOOD PRESSURE: THE OLE OF NITRIC OXIDE
stitute of Normal and Pathological Physiology and Centrum of Cardiovascular Research, lovak Acedemy of Sciences and Centrum of Experimental Medicine, Bratislava, Slovak epublic
echanisms of NG-nitro-L-arginine methyl ester (L-NAME)-induced hypertension involves
ore than a simple inhibition of nitric oxide production with consequent decrease of
asorelaxant activity. Nevertheless, attenuated vascular relaxation and enhanced contraction
different parts of vascular tree belong to the first factors contributing to the increase of
lood pressure (BP). Among other factors, increased level of prostaglandins, reactive oxygen
pecies and increased activity of renin-angiotensin-aldosterone system and sympathetic
ervous system were demonstrated. Since a serious role of nuclear factor NF-κB in the
xpression of nitric oxide synthase (NOS) isoforms was reported, the goal of our study was
analyze a time course of L-NAME effect on nitric oxide synthase (NOS) particular
oforms and NF-κB protein expressions, total NOS activity and BP in rats. NOS activity was
ecreased after 4 weeks of L-NAME treatment in all tissues investigated. We demonstrated
at prolonging the L-NAME treatment to 7 weeks increased NOS activity in the aorta, heart,
nd kidney while NOS activity in the brain parts like brainstem, cerebellum and brain cortex
as decreased more significantly. Further, increased expression of eNOS protein may be
sponsible for increased NOS activity in peripheral tissues, while decreased expression of the
ame NOS isoform in the brainstem, cerebellum and brain cortex led to a more pronounced
ecrease of NOS activity in these parts of brain. Analysis of NF-κB (p65) protein expression
onfirmed the regulatory role of eNOS transcription and/or expression. Since BP increase
ersisted after 7 weeks of L-NAME treatment, we hypothesized that central regulation of BP
predominant in L-NAME-induced hypertension.
upported: VEGA 2/6148/26, APVV-0586-06 and APVV-0538-07.
R Olga Pechanova InSR M
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MOLECULAR MECHANISMS OF VASCULOPROTECTIVE EFFECT OF NITRIC OXIDE Ashok K. Srivastava Centre de Recherche, Centre hospitalier de l’Université de Montréal (CHUM), Montreal, Quebec, Canada
Nitric oxide (NO), in addition to serving as an important vasodilator, has also been suggested
to serve as an antimitogenic and antihypertrophic agent for growth factors and vasoactive
peptides such as endothelin-1 (ET-1) in vascular smooth muscle cells (VSMCs). However, the
exact mechanism by which NO exerts its antimitogenic and antihypertrophic effects is not
well defined. Here we have demonstrated that treatment of A-10 VSMCs with S-nitroso-N-
acetylpenicillamine (SNAP) or sodium nitroprusside (SNP), two NO donors, attenuated the
ET-1-enhanced phosphorylation of several key components of mitogenic, growth promoting
and hypertrophic signaling pathways such as ERK1/2, PKB and Pyk2. On the other hand, the
inhibition of the endogenous NO generation by using N-nitro-L- arginine methyl ester (L-
NAME), a NO synthase inhibitor, increased the ET-1-induced phophosphorylation of these
signaling components. Since, NO mediates its effect principally through a cyclic GMP/ and
soluble guanylyl cyclase (sGC) pathway, we investigated the role of these molecules in NO
action. 8-Br-cGMP, a cell permeant and non-metabolizable analogue of cGMP, exhibited a
similar effect as NO donors and the pharmacological blockade of sGC reversed the inhibitory
effect of NO on ET-1-induced responses. SNAP treatment also inhibited the protein synthesis
induced by ET-1. Taken together, these data demonstrate that NO, in a cGMP-dependent
manner, attenuated ET-1-induced signaling events and hypertrophy in VSMC. It may be
suggested that suppression of ET-1 signaling pathway and hypertrophic responses by NO
contributes towards its vasculoprotective effects.
(Supported by CIHR).
25
PEROXYNITRITE-INDUCED PROTECTION AGAINST ARRHYTHMIAS Agnes Vegh, Attila Kiss, Laszlo Juhasz
ology and Pharmacotherapy, University of Szeged, Szeged, Hungary
gen derived radicals, generated during ischaemia and reperfusion, are
rapidly react and form other highly reactive species, such as peroxynitrite, which is one of the
creased superoxide production rather than to
formation, and this effect might explain the marked antiarrhythmic
ffects of preconditioning and peroxynitrite. There are, of course, a number of possible ways
y which NO may result in antiarrhythmic protection. These include the modulation of
uperoxide production, the release of catecholamines and acetylcholine and the regulation of
e influx and uptake of calcium, etc. They role in the antiarrhythmic protection will also be
iscussed.
Department of Pharmac Nitrogen and oxy
major contributors of myocardial and endothelial dysfunction, cell necrosis, and of
reperfusion-induced ventricular arrhythmias. However, there is accumulating evidence that
high nanomolar or low micromolar concentrations of exogenouly administered peroxynitrite
can be cardioprotective. For example, short (5 min) periods of peroxynitrite infusion, given by
intracoronary route in anaesthetised dogs, induce a preconditioning-like antiarrhythmic
protection, and reduce the formation of endogenous peroxynitrite following a prolonged
period of ischaemia and reperfusion. Such a reduced generation of peroxynitrite (assessed by
the measurement of nitrotyrosine formation in tissue samples taken from the ischaemic
myocardium soon after the reperfusion) may also occur in dogs that are subjected to similar
brief periods of coronary artery occlusion (preconditioning) 5 min prior to a more prolonged
(25 min) ischaemia and reperfusion insult. Since peroxynitrite is formed from equimolar
concentrations of NO and superoxide, a decrease in peroxynitrite generation should result
from either a reduced nitric oxide or a reduced superoxide production. Both preconditioning
and the administration of peroxynitrite increase the plasma nitrate/nitrite (NOx) levels and
these are maintained or even further increased during the prologed test ischaemic period. In
contrast, superoxide production, determined by confocal laser microscopy in tissue samples
taken at reperfusion, markedly decreases following preconditioning and peroxynitrite
adminsitration. These results suggest that under in vivo conditions the reduction in
endogenous peroxynitrite formation is due to a de
a modification of NO
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EFFECT OF PROVINOL ON CARDIAC NA,K-ATPASE DURİNG HYPERTENSİON
Veronika Javorkova1, Lucia Mezesova1, Olga
Institute of Normal and Pathological Physiology, Slovak
Norbert Vrbjar1, Jana Vlkovicova1, Pechanova2, Ramaroson Andriantsitohaina3
1Institute for Heart Research, SAS, 2
Academy of Sciences, Bratislava, Slovakia, 2Biologie Neuro-Vasculaire Intégrée, UMR INSERM 771-CNRS 6214, School of Medicine, Angers, France.
We investigated whether administration of red wine polyphenolic compounds (Provinol)
protects the cardiac Na,K-ATPase during the developing and sustained hypertension. The
hypertension was induced in male rats (LN group) by the nitric oxide synthase (NOS)
inhibitor, L-NAME (40 mg·kg-1·day-1). The Provinol (40 mg·kg-1·day-1) was applied during
development (LNPF4) and persistence of hypertension (LNPF7/3). The enzyme kinetics of
Na,K-ATPase was used for characterization of ATP- and Na+-binding sites. NO-deficient
hypertension by itself lowered the activity of Na,K-ATPase resulting in significant decrease
of Vmax with unchanged Km value for ATP, but with decrease of the enzyme affinity to Na+ as
shown by the 59% increase of KNa value in LN, as compared to controls. Concerning the
ATP-binding site, administration of Provinol to hypertensive animals induced a further
significant decrease of Vmax value by 38% in LNPF4 and by 50 % in LNPF7/3 as compared to
LN. The affinity of the ATP-binding site was significantly decreased in LNPF4 only, as
suggested by marked increase of Km value by 52%. Concerning the Na+-binding site,
administration of Provinol induced a marked increase of Na,K-ATPase activity especially in
the presence of low concentrations of Na+, resulting in decrease of KNa value by 72 % for
LNPF4 and by 69 % for LNPF7/3 as compared to LN. Administration of Provinol induced
different effects on ATP-binding and Na+-binding sites of the cardiac Na,K-ATPase. In the
vicinity of ATP-binding site the effect of Provinol was deleterious, resulting in worsened
utilization of substrate by the enzyme. In the vicinity of Na+-binding site the effect of
Provinol was protective, resulting in increased affinity of the enzyme to sodium.
This research was supported by Slovak Grant Agencies (grant No. VEGA 2/7127/27, APVV-
51-059505).
27
Session IV. Adaptative (protective?) mechanisms in cardiovascular system
28
THE TRANSCR ULATOR OF CARDIAC COL SION
ichael Czubryt, Leon Espira and Lise Lamoureux stitute of Cardiovascular Sciences, St. Boniface Hospital Research Centre and Department
f Physiology, University of Manitoba, Winnipeg, Canada
ardiac fibroblasts synthesize collagens as part of the extracellular matrix, which contributes
the mechanical strength of the myocardium. In response to stresses such as myocardial
farction or hypertension, the heart undergoes remodeling marked by cardiomyocyte
ypertrophy, alterations in chamber dimensions and phenotype conversion of fibroblasts into
yofibroblasts that synthesize large amounts of fibrillar collagens. Excessive collagen
ynthesis impairs contraction and relaxation, eventually contributing to cardiac failure. The
evelopment of improved anti-fibrotic therapies requires a greater understanding of the
ontrol of collagen synthesis. Of note, the transcriptional regulators of collagen synthesis are
ot fully known.
We report here that the basic helix-loop-helix transcription factor scleraxis regulates
e expression of collagen Iα2, the primary collagen expressed in cardiac fibrosis. We show
at scleraxis is expressed in cardiac fibroblasts, and its expression level increases two-fold as
broblasts phenoconvert to myofibroblasts. Stimulation of cardiac fibroblasts with the pro-
brotic growth factor TGF-β induces a four-fold increase in scleraxis expression.
verexpression of scleraxis in NIH 3T3 fibroblasts is sufficient to up-regulate the expression
f collagen Iα2. By in silico analysis, we have identified several putative scleraxis binding
ites in the collagen Iα2 promoter which are conserved in mice, rats and humans. In in vitro
ciferase assays, scleraxis strongly transactivated the collagen Iα2 promoter. Deletion
xperiments reveal that transactivation is critically dependent on the DNA-binding motif of
cleraxis, and is attenuated by deletion of a protein-interaction moiety. Taken together, our
sults strongly support the hypothesis that scleraxis directly regulates cardiac collagen gene
xpression, and may play a key role in cardiac fibrosis.
upported by the Heart & Stroke Foundation of Canada and the Manitoba Medical Service oundation.
IPTION FACTOR SCLERAXIS IS A NOVEL REGLAGEN GENE EXPRES
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EXPRESSION OF THE CARDIAC SIGMA RECEPTORS IN RAT AND MOUSE UNDER PHYSIOLOGICAL AND VARIOUS PATHOLOGICAL CONDITIONS
Excellence for Cardiovascular esearch, Slovak Academy of Sciences, Bratislava, Slovakia
culum leads to modulation of cardiac contractility after stimulation of
cardiom
e can assume that sigma receptors
Marie Novakova, 1Olga Krizanova Department of Physiology, Faculty of Medicine, Masaryk University Brno, Czech Republic 1Institute of Molecular Physiology and Genetics, Centre of R Sigma receptors are recently cloned binding sites for several classes of psychotropic drugs
and steroids. They exist in several subtypes and have been localized in many tissues,
including the heart muscle. A considerable effort has been done to explain the intracellular
mediation of sigma signalling and its physiological role. However, the most important
discovery for understanding the sigma signalling has not yet been done: the endogenous
ligand remains obscure.
In our previous studies we have proved that the IP3 stimulated release of calcium from the
sarcoplasmic reti
yocytes or multicellular heart preparations with sigma ligands. Moreover, we
observed prominent electrophysiological changes (QT prolongation, arrhythmias occurrence)
in isolated rat and guinea pig hearts.
The aim of the present study was to examine the gene expression of sigma receptors in the left
ventricles of rat heart in physiological situation (ageing) and under the effect of various
stressors (hypoxia, cold, and immobilization). We have found that gene expression of sigma
receptors is not significantly changed during ageing, but it is upregulated by strong stress
stimuli, such as immobilization and/or hypoxia. Nevertheless, cold as a milder stressor has no
effect on sigma receptor’s mRNA levels. Signalling cascade of sigma receptors is dependent
on IP3 receptors, since silencing of both, type 1 and 2 IP3 receptors resulted in decreased
mRNA levels of sigma receptors.
Physiological relevance of sigma receptors in the heart is not fully elucidated yet.
Nevertheless, based on the already published data w
participate in contractile responses in cardiomyocytes.
30
INDUCTION OF CARBONIC ANHYDRASE IX IN HYPOXIC RAT CARDIOMYOCYTES: ROLE OF THE MITOCHONDRIA 1Attila Ziegelhöffer, 2Tereza Holotnakova, 1Miroslav Ferko, 1Jana Mujkosova, 1Tana
ab.
hys. Inf., Comenius Univ., Bratislava, Slovakia
) Elucidate the role of mitochondria in control of CA IX expression
ethyl ester of succinate (DMS), diazoxide (DZO) and
much less potent in inducing car9 expression. Surface
xtrusion of succinate and free radicals
hich accumulate in the mitochondria (MIT) due to inhibition the tricarboxylic acid cycle by
OX, succinate dehydrogenase inhibitors or other means. MIT actively contribute to
isruption of O2 sensing and via this mechanism support the expression of CA IX in CM.
upport: Grants APVV 51-027404 and 51-024805, VEGA 2/0173/08, 02/7126/27 as well as
e order of the Slovak Government SP 51/0280901.
Ravingerova, 3Olga Ulicna, 4Iveta Waczulikova, 2Silvia Pastorekova, 2Jaromir Pastorek1Inst. Heart Res., Ctr. Excel. Cardiovasc. Res., SAS.; 2Inst. Virol. SAS.; 3LPharmacobiochem. 3rd Dpt. Int. Med., Fac. Med.; 4Dpt. Nuclear Phys. Biophys., Fac. Math., P
Background: CA IX is a cell membrane-bound isoform of CA acting in cell adhesion and pH
control. It is strongly induced by hypoxia (HOX) and often associated with tumors. The
presence of CA IX in the myocardium was first time revealed by us in 2005. Aims: i)
Ascertain whether CA IX is present in normoxic (NOX) as well as in HOX rat
cardiomyocytes (CM); ii
in CM via modulation of O2 sensing by influencing the HIF-1α pathway. Experimental:
Isolated primary (P) CM and/or immortalized H9c2 CM (I) maintained in culture for 3 weeks
before the experiment. HOX induced with 2 % O2 lasted 48 h; CA IX expression was detected
by immunofluorescence, RT PCR and immunoblotting. HIF-1α pathway modulators applied:
dimethyloxalylglycine (DMOG), dim
tempol (TL). Results and Discussion: In PCM, CA IX and VEGF were present already in
NOX. HOX induced a 2-fold increase in CA IX and strong rise in levels of HIF-1α, Glut-1
and iNOS, but only a moderate elevation of VEGF. The high magnitude of induction of CA
IX gene in comparison with that of the VEGF may be caused by much closer localization of
its HIF binding element on the Ca9 promoter to the transcription initiation site. Similarly as in
PCM, also in ICM were the rodent CA gene (car9) transcription and CA IX protein
expression strongly induced by HOX as well as by DMOG and less by TL. Other modulators
such as DMS and DZO were
localization of CA IX was confirmed in all cell types investigated. Conclusions: CA IX is
present in CM also in NOX and its expression is intimately involved in molecular responses
to HOX and to chemical disruption of O2 sensing. By e
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IS MYOCARDIAL GAP JUNCTION CHANNEL PROTEIN, CONNEXIN-43, A KEY PLAYER OR BYSTANDER IN MODULATION OF CARDIAC LETHAL
RRHYTHMIA SUSCEPTIBILITY?
l and metabolic cell-to-cell communication
ia gap junction connexin channels ensures myocardial synchronisation. In turn, the defects in
A Narcis Tribulova Institute for Heart Research, Slovak Academy of Sciences, Bratislava, Slovakia Background and purpose: Functional electrica
v
connexin expression and/or distribution linked with disorders of intercellular communication
are thought to be arrhythmogenic facilitating occurrence of lethal arrhythmias. We examined,
therefore, topology, expression and phosphorylation of major cardiac gap junction channel
protein, connexin-43 (Cx43) as well as susceptibility of the heart to ventricular fibrillation
(VF) in various models of cardiomyopathy. Experimental approach: Experiments were
conducted on male adult spontaneously hypertensive rats, hyperthyroid rats, STZ-diabetic rats
and diabetic rats treated with thyroid hormone as well as age-matched healthy control rats.
Ventricular distribution of Cx43, its expression and phosphorylation were analysed using
immunofluorescence and Western blotting with mouse MAb. Susceptibility to VF was
examined in isolated heart preparation using electrical stimulation or hypokalemic perfusion.
Key results: Immunodetection revealed besides end-to-end (intercalated disc-related)
enhanced expression of side-to-side Cx43 positive gap junctions in diseased rat hearts. In
addition, total Cx43 and its phosphorylated isoforms were significantly decreased in
hypertensive as well as hyperthyroid rat hearts, while increased in diabetic rat hearts
compared to controls. However, treatment of diabetic rats with thyroid hormone suppressed
both expression and phosphorylation of Cx43. In correlation, the hypertensive and
hyperthyroid rats were much more prone to develop VF, while diabetic rats were much less
when compared to healthy controls. Interestingly, the treatment of diabetic rats with thyroid
hormone increased their vulnerability to VF. Conclusions and implications:: These findings
indicate that intercellular channel protein Cx43 is likely involved in the modulation of
susceptibility of the heart to malignant arrhythmias. It appears that up-regulation of Cx43 is
associated with decrease while down-regulation with increased susceptibility to lethal
arrhythmias. This work was supported by APVV grants 51-059505 and 51-015905.
32
HOW PERIPHERAL ARTERIAL DISEASE MAY PREDICT CORONARY ARTERY EVENTS Amarjit S. Arneja
nal Medicine, University of Manitoba, Winnipeg, Canada
Department of Inter
Lower extremity peripheral arterial disease (LEPAD) is a common syndrome that
affects 16% of North American and European population and is a marker of generalized
atherosclerosis. Individuals with atherosclerotic LEPAD may be asymptomatic; symptomatic
(classic claudications or atypical leg symptoms) or present with critical limb ischemia. The
most cost effective tool for detection of LEPAD is the ankle brachial index (ABI). Patients
diagnosed with LEPAD are six times more likely to die within 10 years than those without
LEPAD.
The high prevalence of diabetes, smoking, hypertension, hyperlipidemia and
hyperhomocystinemia increases the risk of developing LEPAD. Patients with LEPAD have
concomitant coronary artery disease (85%) internal carotid artery disease (60%) and are at
increased risk of atherosclerotic ischemic events including MI and stroke. All patients with
LEPAD should achieve risk reduction and specific treatment targets comparable to those
individuals with established coronary artery disease.
33
VARIABILITY OF CONNEXIN-43 EXPRESSION IN THE AORTA OF RATS WITHDIFFERE
NT GENOTYPE
va
Connexin-43 (Cx43) is a protein of gap junctional intercellular channels which enable rapid
isms involved in
rat strains were used: Wistar (W) and Lewis (L) rats, and spontaneously
hyperte
otensive rats, more abundant fluorescent
pots were found in aorta of L than in W; in hypertensive rats stronger reaction was seen in
orta of hHTG than in SHR. In addition, endothelial Cx43 spots were focally absent in SHR.
estern blot demonstrated presence of two Cx43isoforms in aortic tissue of all rats:
hosphorylated (P1) - related to coupling of gap junction channels and unphosphorylated (P0) -
lated to channels uncoupling. Remarkable differences in total Cx43 expression were also
bserved between used strains: i.e. it was higher in aorta of L than in W and in aorta of hHTG
s compared to SHR (p<0.01). Ultrastructural analysis demonstrated frequent occurence of
ndothelial cell abnormalities of aorta of hypertensive rats. Endothelium-dependent relaxation
f aorta was diminished in SHR and hHTG rats (p<0.05). Blood pressure was 213±4.46 mm
g in SHR and 163±3.25 mm Hg in hHTG (p<0.01). Nonsignificant differences in blood
ressure were found between W and L. The present study demonstrated that there exists
ariability of the aortic Cx43 expression among laboratory rats with different genotype that
ight contribute to development of the arterial functional and structural abnormalities.
upported with APVV-51-059505.
Ludmila OkruhlicoInstitute for Heart Research, SAS, Bratislava, Slovak Republic
conduction of electrical and chemical signals along the vessel, generating vasomotor responses.
Changes in Cx expression may thus represent one of critical mechan
development of cardiovascular diseases. Response of cardiovascular system to
pathophysiological situations shows high inter-individual variation. Involvement of genetic
factors in this variability has also been demonstrated. The aim of the work was to study Cx43
expression in aorta of rats, differing in their genotype. Two normotensive and two hypertensive
1-year-old
nsive (SHR) and hereditary hypertriglyceridemic (hHTG) ones. Cx43 in situ
localization was detected using immunofluorescent method. Cx43 expression was determined
by Western blot analysis and GelPro System. Electronmicroscopy was used for ultrastructural
characterization of endothelial integrity. Blood pressure and NO-dependent relaxation of aortae
were measured as well. Immunolabeling of Cx43 was identified in endothelium and media of
all rats, however with its different intensity: in norm
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Session V. New aspects of heart failure
35
C
YTOKINE IMBAL
awan K Singal, Sanjiv Dhingra, Jan Slezak1 and Anita K Sharma stitute of Cardiovascular Sciences, Faculty of Medicine, University of Manitoba, Winnipeg, anada. Institute of Heart Research, Slovak Academy of Sciences, Bratislava, Slovak epublic
ifferent cytokines in heart failure are modified in a characteristic manner and the details of
eir precise role in this condition are not known. In this regard, tumor necrosis factor (TNF) -
lpha has been suggested to play a role in the progression of heart failure. Interleukin 10 (IL-
0) antagonizes some of the effects of TNF-alpha. We have already shown that heart failure
ubsequent to MI is associated with the decrease in IL-10/TNF-alpha ratio and that, IL-10
odulates the TNF-alpha induced oxidative stress in isolated cardiomyocytes. However,
tracellular signaling events responsible for this are not known. Present study investigates
le of p38 and ERK 1/2 MAP kinases in TNF-alpha induced cardiomyocyte apoptosis and its
odulation by IL-10. Cardiomyocytes isolated from Sprague Dawley rats were exposed to
NF-alpha (10ng/ml), IL-10 (10ng/ml) and IL-10+TNF-alpha (ratio 1) for 4hrs. H2O2
ositive control) and antioxidant trolox (20 μmol/L) were used to confirm involvement of
xidative stress. H2O2 (100 μΜ) increased oxidative stress and apoptosis, TNF-alpha
imicked these effects. Exposure to TNF-alpha increased ROS production, caused cell injury,
creased the number of apoptotic cells and Bax/Bcl-xl ratio. This change was associated with
n increase in p38 and a decrease in ERK 1/2 phosphorylation. IL-10 by itself had no effect
n these MAP kinases, but it prevented TNF-alpha induced changes. Trolox mitigated TNF-
lpha induced changes. Pre-exposure of cells to p38 inhibitor SB-203580, prevented TNF-
lpha induced changes. Inhibition of ERK pathway with PD98059 attenuated protective role
f IL-10 against TNF-alpha induced effects. Present data provide evidence that IL-10
fluences the activation of p38 and ERK 1/2 thereby modulating TNF-alpha induced
xidative stress and cardiomyocyte apoptosis (supported by CIHR).
ANCE IN HEART FAILURE
PInCR D
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RENAL DYSFUNCTION AND HEART FAILURE Jan Murin, Gabriel Kamensky 1st Internal Department, University Hospital, Bratislava, Slovakia 5th Internal Department, University Hospital, Bratislava, Slovakia Evidence for the relationship between renal insufficiency (RI) and cardiovascular (CV) events
is present not only in the dialysis population but also is extended to subjects (heart failure
[HF] patients [p] included) with more moderate (even mild) RI.
There is an association of CV events with renal function in p with HF or post
myocardial infarction (MI): (a) PRIME II study (stable advanced HF, NYHA III/IV, EF< 35
%, 1906 p, glomerular filtration (GF) by Gault-Cockroft) – quartiles of GF (Q1 vs Q4) versus
all cause mortality with HR of 2,85 (S), (b) CATS trial (baseline renal function, prediction of
HF development after anterior MI, 298 p, 1 year follow-up [FU]: HF in 24 % p (best tertile),
28,9 % p (middle) and 41,2 % p (worst), (c) VALIANT study (MI p with LV dysfunction or
HF, 14 527 p, 25 m FU) – each GF of 10 ml/min below 81 ml/min means 1,1 fold increased
risk of death/nonfatal CV complications.
We should think of RI in p with HF or risky for HF development. Better treatments
here (neurohormonal drugs) improve prognosis.
37
MECHANISMS OF SUBCELLULAR REMODELING IN CONGESTIVE HEART AILURE
f Medicine, University of Manitoba, Winnipeg, Canada R2H 2A6
associated with myofibrils (MF), sarcoplasmic reticulum (SR) and sarcolemma (SL)
rem estive heart failure,
echanism
odeling and reduce the depression in the activities
ay be due to prolonged
ctivation of multiple hormonal systems. (Supported by a grant from the Canadian Institutes
f Health Research)
F Naranjan S. Dhalla Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, Facultyo Although cardiac remodeling (changes in shape and size of the heart) has been shown to be
odeling (changes in biochemical and molecular composition) in cong
the m s of these alterations are not fully understood. Since congestive heart failure is
invariably associated with activation of renin-angiotensin system (RAS), sympathetic nervous
system (SNS) and serotonergic system (STS), we have tested the effects of blocking these
systems on subcellular remodeling in hearts failing due to myocardial infarction in rats.
Marked alterations in the activities, protein contents and gene expression of MF, SR and SL
were observed in the failing hearts 8 weeks upon inducing myocardial infarction. Treatments
of infarcted animals with blockers of RAS, SNS and STS for 5 weeks were found to improve
cardiac function, attenuate subcellular rem
of MF, SR and SL in the failing hearts. These data suggest that heart dysfunction, cardiac
remodeling and subcellular remodeling in congestive heart failure m
a
o
38
ALTERED CONTRACTILE PROTEIN PHOSPHORYLATION DURING HEART FAILURE Zoltan Papp Division of Clinical Physiology, Institute of Cardiology, Faculty of Medicine, University of Debrecen, Hungary As a member of the G protein family, Gαq is a GTP-activated protein whose activation is
linked to the development of chronic heart failure. Through the activation of phospholipase
Cβ, Gαq is coupled to a protein kinase C (PKC)-mediated cascade, and in cardiac muscle it is
regarded as an important transducer of neurohumoral signals that include endothelin, nor-
epinephrine and angiotensin II. Hence, chronic Gαq activation presumably contributes to the
development of changes in the phosphorylation and expression of myocardial proteins leading
to myocardial hypertrophy and ultimately to heart failure.
We hypothesized that the mechanical changes in the cardiomyocytes would reflect the
involvement of PKC-modulated myofilament proteins in the pathogenensis of dilated
cardiomyopathy (DCM). Therefore, mechanical and biochemical alterations were investigated
in permeabilized cardiomyocytes along with the progression of DCM in a transgenic mouse
line overexpressing the activated Gαq protein (Tgαq*44). The isometric force, its Ca2+
sensitivity (pCa50) and the turnover rate of the actin-myosin cycle (ktr) were determined at
sarcomere lengths (SLs) of 1.9 μm and 2.3 μm before (at 4 and 10 months of age) and after
hemodynamic decompensation (at 14 and 18 months of age) in Tgαq*44 and in age-matched
ontrol cardiomyocytes. The SL-dependence of pCa50 was not different in Tgαq*44 and
ontrol hearts. In contrast, a significant increase in pCa50 was observed in the Tgαq*44
ardiomyocytes (ΔpCa50: 0.10-0.15 vs. the controls) after 10 months of age that could be
iminished by exposures to the catalytic subunit of protein kinase A (PKA). Accordingly, a
ecline in endogenous PKA activity and decreased troponin I phosphorylation were detected
fter 10 months in the Tgαq*44 hearts. Finally, the maximal Ca2+-activated force (Fo) and ktr
ere lower and the passive force (Fpassive) was higher at 18 months in the Tgαq*44
ardiomyocytes compared to the control. These mechanical alterations were paralleled by a
bust increase in β-myosin heavy chain expression in the Tgαq*44 hearts at the terminal
tage of DCM.
In conclusion, our results question the primary role of PKC-dependent mechanisms in
e myofibrillar contractile function of Tgαq*44 mice and suggested that an initial decrease of
KA signaling and subsequent changes in myofilament protein expression may contribute to
e development of dilated cardiomyopathy in Tgαq*44 hearts.
c
c
c
d
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s
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P
th
39
TO BE ON TARGET – AIMED ON BETTER CARDIOVASCULAR PREVENTION: ONTARGET RESULTS.
ardiovascular mortality will still be the leading cause of death in countries also up to 2010,
study with ARB performed ever.
Patient
Andrej Dukat2nd. Department of Internal Medicine Comenius´ University, Bratislava, Slovakia. C
high-risk patient populations represent important target for their secondary prevention. Since
decades two classes of drugs affecting renin-angiotensin-aldosterone system are used in high-
risk patients with essential hypertension. HOPE study was the first, that showed significant
benefit with ACE-inhibitor ramipril in high-risk patients. ONTARGET programme was
designed in order to show the non-inferiority of ARB telmisartan in these settings.
ONTARGET is one of the largest studies evaluating patients with essential hypertension. It
recruited altogether 25 620 patients, it was the largest
s were over 55 years in high risk: present history of cardiovascular disease: coronary,
cerebral, or peripheral localization, or diabetes mellitus with complications. They were treated
with ramipril 10mg daily, or telmisartan 80mg daily, or with their combination. Follow-up pe-
riod was 5 years. TRANSCEND substudy evaluated hypertensive patients not tolerating
ACE-inhibitors. It followed-up 5 926 hypertensives, treated with telmisartan 80mg daily.
There are other 7 substudies in evaluation of other effects of secondary prevention among
hypertensives. Primary endpoint was the composite: cardiovascular death, non-fatal
myocardial infarction, stroke or hospitalization for heart failure.
Both ACE-inhibition and ARB (ramipril and telmisartan) have proved their effect in the
secondary prevention of the high-risk hypertensives, with noninferiority of telmisartan.
Combination of both above mentioned drugs did not bring any additional benefit, but an
increase of side-effects.
40
BNP IN ACUTE HEART FAILURE Milan Luknar, Peter Lesny, Eva Goncalvesova
nd Transplant Department, National Institute of Cardiovascular Diseases,
he aim of
of hemodynamic parameters
AP = 10.6 +/- 4.1 mmHg vs. 7.3 +/- 2.9, p< 0.01; PCWP = 24.5 +/-
.9 mmHg vs. 18.4 +/- 4.3, p< 0.01; BNP= 739 +/- 328 pg/ml vs. 588 +/- 281 pg/ml, p<
.01). The recovery of the filling pressures to basic levels was accompanied by BNP level
crease to 742 +/- 352 pg/ml. Responders (13 pts.) and non-responders (4 pts.) showed no
ifference in the level of the ventricular filling pressure decrease. LVEDD was greater than
5 mm in 12 responders and in only one non-responder. Conclusion: In patients with acute
ecompensated HF, BNP level immediately reflects changes in ventricular filling pressures.
redictive reliability of hemodynamic changes appears to be higher in a more pronounced
ft ventricular dilation. These results seem to further support the concept of treatment
djustment and management of acute HF based on BNP levels. Repeated BNP measurement
Heart Failure aBratislava, Slovakia Introduction: Erroneous diagnosis and management of acute heart failure (HF) can have a
devastating effect on the patient. Constant effort is being performed to develop a simple non-
invasive correlate of HF. Plasma BNP and NT-proBNP are released from ventricular tissue in
response to volume overload and/or increased wall tension. In acute HF, ventricular wall
tension rises as a consequence of increased filling pressures that can be invasively measured
as pulmonary capillary wedge pressure (PCWP) and right atrial pressure (RAP). T
the study was to evaluate BNP changes in the acute hemodynamic test in patients with acute
decompensated HF. Patients and methods: 17 patients (15 males), candidates of heart
transplant (HTx), in whom severe pulmonary hypertension (PH) was diagnosed by central
hemodynamic examination (pulmonary vascular resistance >/= 4 Wood units and/or
transpulmonary gradient >/= 15 mmHg), were examined. Mean age was 50 +/- 6 yrs., mean
ejection fraction 21 +/- 5 %, left ventricle end-diastolic diameter (LVEDD) 72 +/- 9 mm. The
primary diagnosis was dilated cardiomyopathy (CMP) in 10 pts., coronary heart disease in 6
pts., and hypertrophic CMP in 1 pt. In all of them, PH reversibility test was performed using
infusion of vasodilating prostaglandine E1 (PGE1). BNP level was measured at the baseline,
at maximum hemodynamic effect of PGE1, and after resolution
to the basal values (after discontinuation of PGE1). Patients who reached 20% and greater
decrease in BNP levels in comparison with baseline values were considered responders.
Results: A significant drop in ventricular filling pressures and BNP levels was registered
during PGE1 infusion (R
2
0
in
d
6
d
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le
a
41
might improve the titration of treatment in patients with acute heart failure in the intensive
care setting.
42
Session VI. Mechanisms of cell death and survival
43
HP
YPOXIA-IND COMPLEXES ROVOKES BN ENTRICULAR YOCYTES
orrie A. Kirshenbaum stitute of Cardiovascular Sciences, University of Manitoba, Winnipeg, Canada
he cellular factor E2F-1 is known to regulate a variety of processes including G1 exit and
poptosis. Previously we have shown that E2F-1 provokes cell death of post-mitotic adult and
eonatal ventricular myocytes, however, the underlying mechanism was undetermined. In this
port we show that E2F-1 triggers cell death of ventricular myocytes through a mechanism that
irectly impinges upon the intrinsic apoptotic pathway and involves the activation of the death
ctor Bnip3. Overexpression of E2F-1 in cells caused a 4.9 fold increase (p<0.01) in myocyte
ell death compared to control cells. E2F-1 provoked mitochondrial perturbations consistent
ith hypoxic injury and the intrinsic death pathway including permeability transition pore
pening, Smac/Dibalo release and caspase-3 activation. Bnip3 gene transcription was increased
y 2.1 fold in cells expressing wild type E2F-1 but not in cells expressing a transactivation
efective mutant. During hypoxia, Rb was proteolytically cleaved and inactivated in ventricular
yocytes. In contrast to normoxic control cells, ChIP analysis verified increased binding of
2F-1 to the Bnip3 promoter during hypoxia- a finding consistent with the induction of Bnip3
anscription. The Bnip3 homologue, Nix/Bnip3L was unaffected in ventricular myocytes by
ither E2F-1 or hypoxia. Genetic ablation of E2F-1 or expression of a caspase resistant form of
b suppressed basal and hypoxia-inducible Bnip3 gene transcription. Furthermore, loss of
nction mutations of Bnip3 abrogated mitochondrial defects and cell death elicited by E2F-1.
o our knowledge the data provide the first direct evidence that de-regulated E2F-1 activity
uring hypoxia impinges upon the intrinsic death pathway through the transcriptional activation
f Bnip3 in the heart. Further we show mechanistically that basal and hypoxia-inducible
ctivation of the Bnip3 promoter is continent upon the presence of the cellular factor E2F-1.
UCED DISRUPTION OF RB/E2F-1 INHIBITORYIP3 GENE EXPRESSION AND CELL DEATH OF V
M LIn
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44
POST-ISCHEMIC ENDOTHELIAL INJURY AND ITS PROTECTION BY ISCHEMIC PRECONDITIONING Andrzej Beręsewicz
ol, Warsaw, Poland
pproximately 25% of patients undergoing reperfusion therapy for myocardial infarction will
Postgraduate Medical Scho A
suffer from “no-reflow phenomenon” that would limit the benefits of the reperfusion. The
mechanism of the phenomenon is not completely understood but may involve reperfusion-
induced injury to the coronary endothelial cells. It is believed that by preventing this post-
ischemic endothelial injury it would be possible to increase the benefits of the reperfusion
therapies.
Based on the experiments in the model of ischemia/reperfusion (IR) in the isolated
Langendorff-perfused guinea-pig heart we propose the following mechanism of coronary
endothelial injury (Fig. 1). IR results in increased cardiac generation of endothelin (ET-1) and
nitric oxide (NO). ET-1 via ETA receptor, in the unknown mechanism stimulates superoxide
(O2-) generation by mitochondrial complex II. This mitochondrial O2
- leads to activation of
vascular NADPH oxidase. NADPH oxidase mediates the conversion of xanthine
dehydrogenase (XDH) to xanthine oxidase (XO). XO-derived O2- reacts with NO to produce a
toxic product of this reaction, e.g., peroxynitrite that mediates endothelial injury. Our
evidence indicates that ischemic preconditioning affords endothelial protection IR hearts by
preventing post-ischemic ET-1, and thus O2- generation, whereas NO generation remains
unaffected.
These results emphasize a therapeutic potential of various anti-ET-1, anti-NADPH oxidase,
nd/or anti-XO treatments in preventing endothelial injury and its adverse consequences in IR
eart.
a
h
45
HYPOXIC ADAPTATION PROTECT CARDIAC CELLS VIA UPREGUALTION AUTOPHAGY IN ASSOCIATION WITH BAG-1 PROTEIN
my and Dipak K. Das onnecticut School of Medicine, Farmington,
T 06030-1110, USA.
ring hypoxia-reoxygenation in cardiac cells. However, the exact role of autophagy
induced
2 cells slightly induced the protein expression of LC3-II, an autophagic marker
protein present in the autophagosomal membrane. Also, the protein expression of Bag-1 is
also slightly induced during hypoxia-reoxygenation. However, hypoxic adaptation prior to
hypoxia reoxygenation further induced the protein expression of LC3-II and BAG-1. Our
immunofluorescence analysis further show that LC3-II level has been enhanced during
hypoxic adaptation. Furthermore, treatment with BAG-1 siRNA attenuated hypoxic
adaptation induced LC3-II and BAG-1 proteins in cardiac myoblast cells. Moreover, hypoxic
adaptation-induced cardiac cell viability studied using 3,(4,5-Dimethylthiazol-2-yl)-2,5-
diphenyltetrazolium (MTT) was reduced by Bag-1 siRNA treatment. The release of cardiac
dehydrogenase (LDH) studied using the culture supernatant was
duced by hypoxic adaptation, but Bag-1 siRNA treatment abolished the hypoxic adaptation-
tion with BAG-1 protein.
Narasimman GurusaCardiovascular Research Center, University of CC
Autophagy is an intracellular process in which cell digests its own constituents via
lysosomal degradative pathway. Though autophagy has been shown in several cardiac
diseases like heart failure, hypertrophy and ischemia reperfusion injury, the role and the
regulation of autophagy is still largely unknown. Studies have indicated that autophagy is
induced du
in hypoxia-reoxygenation is not known. Hypoxic adaptation is known to induce
survival signaling in cardiac cells, and further it is shown to protect them. BAG-1 is a
multifunctional pro-survival molecule binds protect cardiac cells from apoptosis induced by
several stimuli. In the present study, H9c2 cardiac myoblast cells were subjected to either 30
min of hypoxia followed by reoxygenation for 1 hr (HR) or hypoxic preconditioning (HPC),
where the cells were subjected to 3 cyclic episodes of 5 min hypoxia and 5 min
reoxygenation, followed by HR. Hypoxia was given by placing the cultured plates into an air-
tight hypoxic chamber placed in a humidified 37oC CO2 incubator, and passing the mixture of
95% Nitrogen and 5% CO2. Reoxygenation was given by placing back the cultured plates in a
humidified 37oC CO2 incubator saturated with air. We found that hypoxia-reoxygenation
injury in H9c
cell death marker lactate
re
induced reduction of LDH release. These results indicate that cardiac protection elicited
during hypoxic adaptation is mediated at least in part via upregulation of autophagy in
associa
46
HIBERNATING MYOCARDIUM: ADAPTATION REMODELING OF CARDIAC MYOCYTES TO CHRONIC ISCHEMIA AND RETURN TO FUNCTIONAL
YOCARDIUM
rch, Slovak Academy of Sciences, Bratislava, Slovak Republic University of Manitoba, Winnipeg, Canada
are demonstrated as the most effective maneuvers. A new
M Jan Slezak, Narcis Tribulova, Ludmila Okruhlicova and Pawan Singal1
Institute for Heart Resea1Institute of Cardiovascular Sciences,
The imbalance between myocardial oxygen/nutrition supply and demand leads to a condition
of new equilibrium where myocardial necrosis is not present but cardiac myocyte slows down
to adapt to match energy supply. Molecular mechanisms, resulting in this cardiomyocyte
remodeling and adaptation in the hibernating myocardium are not fully understood.
Twenty mongrel dogs and forty rats were used to study effects of acute ischemia and chronic
hypoperfusion. Particularly, substructural changes in relation to the metabolism in stunned,
hibernating and Ca overloaded myocardium before and after reperfusion were evaluated in
detail.
Adaptation process appears to be connected with a down regulation of energy utilization that
prevents an immediate development of ischemia at the expense of an attenuated level of
contractile function. Cardiomyocytes decrease their differential functions and revert to an
embryonic character that is concerned with functions exclusively dedicated to their own
survival and resemble neonatal cardiomyocytes. Structural changes in hibernating
cardiomyocytes are characterized by loss and disorganization of myofibrils, accumulation of
glycogen, increased amount of phagosomes, alterations of nuclei in size and shape,
occurrence of small dark mitochondria of various shapes and densities and cytoplasmic
vacuolization. All these changes give the cardiac myocyte neonatal like appearance.
Extracellularly, one can find features of fibrosis and disturbed and/or diminished number of
gap junctions. Relatively large variability among cardiac myocyte physiological function and
physical performance is reflected in the substructural features of myocytes in sensitivity to the
ischemic stress. Transmural heterogeneity in the ventricular response to injury has
multifactoral origins including metabolic and flow differences in the subepicardial and
subendocardial regions of the ventricle. The extent and the degree of structural alterations of
hibernating myocardium determine left ventricular function recovery after restoration of
blood flow to the area. The most effective strategy for the treatment of hibernating
myocardium is to reinstate blood-flow by surgical revascularization or by neovascularization.
Different growth factors, angiopoietin, retroinfusion of liposomal eNOS, endothelial
progenitor cells, and resveratrol
47
form of therapy for heart disease refractory to conventional therapy draws on cellular
transplantation. Supported by VEGA grant 2/7094/27
48
Poster Session
ABSTRACTS OF POSTER PRESENTATIONS
Part I. OMEGA-3 FATTY ACİDS ATTE UATE DOWN-REGULATİON OF MYOCARDİAL CONNEXİN-43 İN SPONTANEOUSLY HYPERTENSİVE AND HEREDİTARY HYPETRİGLYCERİDEMİ RATS. Barbara Bacova, Katarina Dlugosova1, Miroslav Barancik1, Ludmila Okruhlicova1, Narcis Tribulova1
Faculty of Life Sciences, Comenius University, Bratislava, 1Institute for Heart Research, SAS, 2Bratislava, Faculty of Medicine, Comenius University, Bratislava, Slovak Republic
Background and purpose: Epidemiological and experimental studies suggest that omega-3
fatty acids (omega-3 FA) and lipids lowering drugs statins reduce the incidence of sudden
cardiac death, presumably due to ventricular fi illation (VF). We have previously shown that
both atorvastatin and omega-3 FA decreased susceptibility to VF in rat models of genetically-
induced dyslipidemia and hypertension (1,2). To elucidate the possible antiarrhythmic
mechanisms we focused on intercellular ch nel protein connexin-43 (Cx43), which is
responsible for cell-to-cell electrical coupling and myocardial synchronization. Experimental
approach: Spontaneously hypertensive (SHR) and hereditary hypertriglyceridemic rats
(HTR) as well as age-matched healthy Wistar or Lewis rats were fed with omega-3 FA
(30mg/day) or atorvastain (0.05mg/day) for two month and compared with untreated ones.
Some biometric parameters were monitored during and at the end of experiments. Expression
of Cx43 in left ventricles of treated and untreated rats was examined by immunobloting and
specific MAB. Key results: Omega-3 FA reduced significantly blood pressure in SHR as well
as serum triglycerides in HTR at the same leve as atorvastatin, while they did not affect body
or heart weights. Myocardial Cx43 expression was significantly reduced in left ventricles of
both SHR and HTR. Omega-3 FA and atorvastatin attenuated these abnormalities.
Conclusions and implications: Results indicate that modulation of Cx43 expression due to
omega-3 FA or atorvastatin can likely be involved in their antifibrillating effects. It is possible
that the treatment can affect turnover and/or and this should be
analyzed in further studies. This work was supported by APVV 51-059505.
1. Knezl et al. Cardiology 2007, Suppl. 1, p.19S; 2, Tribulova et al., J Interv Cardiac
Electrophysiol 2008, 21, p.180.
N
C
br
an
l
gene expression of Cx43
49
TIS
HE EFFECT OF QUERCETI RFUSION INJURY IN OLATED RAT HEART
Monika Bartekova1, Dezider Pancza1, Olga Krizanova2, Albert Breier2, Jan Styk1, Tana Ravingerova1
1 r Heart Research SAS, Institute of Molecular Physiology and Genetics SAS, Excellence for Cardiovascular Research of SAS, Bratislava, Slovakia
of polyphenolic compounds termed
cy of flavonoids against I/R injury have demonstrated that quercetin exerts
limited evidence about the effect of quercetin on global myocardial I/R injury. Therefore, the
an only speculate
N ON ISCHEMIA/REPE
2Institute foCentre of
Introduction: Quercetin is a plant-derived dietary compound with potentially benefitial
effects on cardiovascular diseasases. It belongs to a group
flavonoids, which have been reported to possess antioxidant effects. The studies focused on
antioxidant efficien
robust protective effects in renal, cerebral and hepatic I/R models. However, there is only a
aim of the current study was to examine the effect of quercetin on isolated rat heart during
ischemia and reperfusion.
Methods: Hearts from adult male Wistar rats were isolated and perfused according to
Langendorff. After initial stabilization, hearts were 15 minutes perfused with quercetin
(15µmol/l in Krebs-Henseleit solution), just before 30 min global ischemia followed by 120
min reperfusion. Changes in left ventricular developed pressure (LVDP) and +/-dP/dtmax
were measured during initial 40 minutes of reperfusion. After the end of experiment the
hearts were stained with tetrazolium to estimate the size of infarction.
Results: Our study showed that quercetin improved postischemic recovery of functional
parameters of isolated hearts. This improvement was manifested by significantly higher
values of postischemic recovery of LVDP, +dP/dtmax and -dP/dtmin, and significantly lower
increase of diastolic pressure. Quercetin had no effect on the heart rate during the whole
experiment and coronary flow was non-significantly increased during reperfusion. Quercetin
administration also significantly reduced infarct size in hearts after 30 min global ischemia
and 120 min reperfusion.
Conclusion: Pretreatment of the hearts with quercetin had a significant positive effect on
postischemic functional recovery of isolated hearts and irreversible myocardial injury after
30-min global ischemia. Our results are in correlation with other beneficial effects of
quercetin and other flavonoids on cardiovascular system. On the other hand, our results did
not reveal potential mechanisms involved in cardioprotection. Hence, we c
about its role as an antioxidant in this protection. Supported by grant VEGA SR 2/0173/08.
50
3-OMEGA POLYUNSATURATED FATTY ACIDS TREATMENT IMPROVES CONNEXIN43 EXPRESSION IN AORTA OF AGED SHR
udmila Okruhlicova , Narcisa Tribulova1
, Comenius niversity, Bratislava, Slovakia
ere performed on 1-year-old male SHR and normotensive Lewis
dditionaly, subcellular
ortic NOS activity by 78% in SHR. In LEW rats, PUFA only
Katarina Dlugosova1, Marcela Mitasikova1, Ruzena Sotnikova2, Iveta Bernatova3, Peter Weismann4, L 1
1Institute for Heart Research, 2Institute of Experimental Pharmacology, 3Institute of Normal and Pathological Physiology, Slovak Academy of Sciences, 4Medical FacultyU Hypertension, associated with endothelial dysfunction and structural remodeling of the vessel
wall is also characterized by changes of connexin43 (Cx43) - protein of intercellular gap
junction channels. These enable direct communication between adjacent cells and thus
regulate vasomotor responses of vessels. 3-Omega polyunsaturated fatty acids (PUFA)
supplementation enhances protection against cardiovascular events. Therefore the aim of this
study was to examine the effect of PUFA on expression of Cx43 gap junction protein and
ultrastructure of endothelial intercellular junctions in the aorta of spontaneously hypertensive
rats (SHR). Experiments w
(LEW) rats that were divided into untreated and treated with PUFA (30 mg/day) for 2 months.
Thoracic aorta of all rats was processed for: immunofluorescence and Western blot analysis of
Cx43 and ultrastructural examination. In addition, NOS activity and relaxation of the aortae
were determined. Results showed heterogeneously reduced distribution of Cx43 fluorescent
spots in the aortic endothelium and media of SHR when compared to LEW. Parallel, Cx43
expression was also suppressed in the aorta of SHR (p<0.05). A
alterations of interendothelial tight junctions, impaired endothelium-dependent relaxation and
decreased NOS activity in the aorta of SHR. Omega-3 fatty acids significantly suppressed
blood pressure in both SHR and LEW in comparison to untreated controls (p<0.001,
p<0.003). PUFA diet increased Cx43 immunofluorescence pattern and Cx43 expression in the
aorta of SHR comparing with untreated controls (p<0.05), while no significant changes were
seen in treated LEW rats. PUFA weakly tended to improve the aortic acetylcholine-dependent
response and stimulated a
slightly affected aortic relaxation as compared to untreated rats, but they markedly stimulated
the enzyme activity. Data suggest that PUFA supplementation may contribute to improvement
of intercellular gap junctional communication and to reparation of the aortic function during
hypertension. Supported by APVV–51-059505.
51
ENDOGENOUS PROTECTIVE MECHANISMS IN ACUTE DIABETIC RAT HEART: DIFFERENT INVOLVEMENT OF FREE RADICALS
ingerova , Attila Ziegelhöffer
rn.l Med., Fac. Med., Comenius Univ., Bratislava, Slovakia
Miroslav Ferko1, Jana Mujkosova1, Tereza Holotnakova2, Dana Kincelova3, Iveta
Waczulikova3, Olga Pechanova4, Olga Ulicna5, Tana Rav 1 1
1Inst. Heart Res., Ctr. Excel. Cardiovasc. Sci., SAS.; 2Inst. Virol. SAS; 3Dpt. Nuclear Phys. Biophys., Fac. Math., Phys. Inf., Comenius Uni.; 4Inst. Normal Pathol. Physiol., SAS; 5Lab. Pharmacobiochem., 3rd Dpt. Inte Background: Mitochondria (MIT) from hearts of rats with acute streptozotocin (STZ) -
diabetes (DIA) exhibit functional remodeling (REM) of subcellular membrane systems that is
triggered in part by free radicals (FR) and also reflects the outcome of endogenous protection
(EP). Aim: distinguish and elucidate those functions of the DIA-REM MIT membranes,
which are associated with EP in the acute DIA hearts. Experimental: DIA - induced by STZ
55 mg/kg i.p. Male Wistar rats (220+20g). Experiment was terminated on the 8th day after
STZ when the DIA rats exhibited an increase in (%): glucose 333.96, triacylglycerols 370.4,
cholesterol 153.4 and glycohemoglobin 189.6 in the blood. In heart MIT there were
investigated: oxidative phosphorylation (OP), the oxidized Q10, conjugated dienes (CD), total
MIT NOS activity, NFκB, eNOS, expression hypoxic genes and CA IX (carbonyl anhydrase),
fluidity (MF) and trans-membrane potential (MP) of the MIT membranes. Results: DIA heart
exhibited FR-induced damage to MIT indicated by ~ 17% (p<0.05) increase in oxidized Q10
but no considerable rise in CD formation in membrane lipids and expression of MIT eNOS as
well as decreased S3 and S4 O2 consumption, RCI and the rate of OP (all p<0.01). Further,
NFκB and MF were increased (both p<0.01), MP decreased (p<0.001), but the latter change
was associated with its increased stability. Linear regression analysis revealed significant
association (r=0.67; p<0.05) between the increase in MF and the decrease in MP in DIA MIT.
In contrast to healthy controls, DIA heart show increased expression of CA IX - a process
mediated. via the HIF-1 transcription factor. Conclusions: The relatively little oxidative
damage to membrane lipids, increase in NFκB and MF as well as in capability of the DIA
heart MIT to maintain MP and the upregulation of hypoxic genes, particularly that of CA IX,
all testify for active participation of EP processes in acute DIA heart. In the latter processes
FR are playing dual role. They are involved in damaging, but also in signaling towards
induction of EP mechanisms. Grants: VEGA SR 2/7126/27, 2/0173/08, APVV 51-027404, SP
51/0280901
52
FEASIBILITY AND SAFETY OF INTRACORONARY INJECTION OF MESENCHYMAL STEM CELLS IN SEVERE ISCHEMIC CARDIOMYOPATHY. MMEDIATE, INTERMEDIATE, AND LONG-TERM FOLLOW-UP
,
edure. All others are alive, 3 of them in good clinical condition. Conclusion:
tracoronary application of MSC in severe ischemic cardiomyopathy is safe and feasible.
hanges at 12 weeks after the procedure are promising but more data are needed to evaluate
e efficacy and medical benefit of this technique.
I Eva Goncalvesova1, Jan Lakota2, Viliam Fridrich1, Pavol Povinec3, Milan Luknar1
Juraj Fabian1 1National Institute of Cardiovascular Disease, Bratislava, Slovakia, 2National Cancer Institute, Bratislava, Slovakia, 3Biont PET Centre, Bratislava, Slovakia
Introduction: Mesenchymal stem cells (MSC) have documented a potential of cardiac
regeneration in animal models. Data on use of MSC in humans are very rare. The main reason
for this is apprehension of myocardial infarction (MI) induction and undesirable
transformation of MSC. Aim: To evaluate safety and feasibility of intracoronary injection of
autologous MSC in patients with ischemic cardiomyopathy. Patients and methods: Ten heart
failure pts (all males, mean age 49.6 ± 4.8 years) with a history of MI and severe systolic
dysfunction (mean left ventricular ejection fraction (LVEF) 18.7 ± 7.6%) were included. In
five of them coronary angiography showed nonsignificant stenoses. Five others had coronary
lesions not suitable for any intervention. In 4 of all 10 pts. viable myocardium was detected
using SPECT thalium scintigraphy. 30 mL of bone marrow blood from the iliac crest was
obtained. The MSC (CD45, CD34, CD 117, CD38, CD71, CD3 negative; CD90, CD44,
CD13 positive) were isolated and expanded ex vivo. Coronary catheterization was performed
using an over-the-wire balloon catheter. Suspension of MSC was injected in four 3 ml boluses
during 3-minutes low pressure artery occlusions. Mean number of cells injected was 2.3 ±
1.0x10e7. NYHA class, six minutes walking distance (6mWD), peak oxygen consumption
(pVO2), left ventricular end diastolic diameter (LVdD), LVEF, wall motion score (WMS),
and brain natriuretic peptide (BNP) were evaluated before and 12 weeks after the procedure.
Mean follow-up time of the patients was 15 ± 6 months. Results: No clinical, ECG or
humoral signs of acute MI were observed. No symptomatic or significant dysrhythmias
occurred immediately after the procedure. After 12 weeks there was no significant change in
NYHA class, resting LVEF or WMS. Increase of 6mWD (421±112 vs 472±122 m, p=0.05)
and pVO2 (16.6± 3.2 vs 20.3±5.2ml/kg/min, p =0.02), and decrease of LVdD 63.5 ± 26.5 vs
59.5± 25.8 mm, p = 0.02), and BNP (532± 650 vs 359± 513 pg/ml, p=0.02) were recorded.
One patient underwent heart transplantation one year, 2 died suddenly 7 and 5 months, resp.,
after the proc
In
C
th
53
SEXUAL DIMORPHISM IN FUNCTIONAL PROPERTIES OF CARDIAC NA,K-ATPASE IN SHR
1 1 1Veronika Javorkova , Jana Vlkovicova , Lucia Mezesova , Olga Pechanova2, Norbert
art Research, SAS, 2Institute of Normal and Pathological Physiology, Slovak Vrbjar1 1Institute for HeAcademy of Sciences, Bratislava, Slovakia.
The present study deals with investigation of functional properties of the cardiac Na,K-
ATPase in 16 weeks old male and female spontaneously hypertensive rats (SHR). The Na,K-
ATPase activity in the presence of increasing concentrations of ATP, as well as Na+ was
lower in SHR of both genders, as compared to respective normotensive controls. Evaluation
of kinetic parameters revealed a significant decrease of the maximum velocity (Vmax) in males
(30% for ATP-activation, 40% for Na+-activation), as well as in females (24% for ATP, 29%
for Na+), indicating a hypertension-induced diminution of the number of active enzyme
molecules in cardiac sarcolemma. The Michaelis-Menten constant (Km) remained unchanged
by hypertension in both genders. The concentration of sodium that gives half-maximal
reaction velocity (KNa), increased by 38% in male and by 70% in female SHR. This
deterioration in the affinity of the Na+-binding site together with decreased number of active
Na,K-ATPase molecules are probably responsible for the impaired enzyme function in hearts
of SHR. Direct comparison of SHR of both genders showed, that the enzyme from female
hearts seems to be adapted better to hypertension as documented by its increased activity as a
consequence of improved ability to bind and utilize ATP, as suggested by 32% decrease of
Km value in females. In addition, the enzyme from female hearts is able to increase its activity
(by 41%) in the presence of increasing sodium concentration even in the range where the
enzyme from male hearts is already saturated.
This study was supported by Slovak Grant Agencies (grant No. VEGA 2/7127/27 and APVV-
51-059505).
54
PART II. ATORVASTATIN A D OMEGA-3 FATTY ACIDS DECREASE SUSCEP BILITY
IN-43 IMPLICATİON.
Vladimir Knezl2, Peter Weismann3, Ludmila kruhlicova1, Jan Jakubovsky, Narcis Tribulova1.
ent. Immunostaining of fibronectin was
ent. Cx43 immunopositivity was confined to intercalated disc-related gap
istar rats, while pronounced lateral (side-to-side) localization of Cx43
as demonstrated in hHTG rat heart ventricles. This abnormal pattern of distribution was not
liminated either by either omega-3 FA or atorvastatin. However, immunostaining of Cx43
as stronger in treated Wistar and hHTG rat hearts. Conclusions and implications: Results
howed clear-cut antifibrillating effects of both omega-3 FA and atorvastatin, while up-
gulation of Cx43 can be implicated. It is possible that treatment can modulate turnover
nd/or gene expression of Cx43 and this should be analyzed in further studies. This work was
N TOF HYPERTRIGLYCERIDEMİC RAT HEART TO LETHAL ARRHYTHMIAS. CONNEX
Lucia Kolenova, Katarina Dlugosova1, OFaculty of Medicine, Comenius University, Bratislava, 1Institute for Heart Research, SAS, Bratislava 2Institute of experimental Pharmacology SAS, , 3Department of Anatomy, Faculty of Medicine, Comenius University, Bratislava
Background and purpose: We have shown previously that hereditary hypertriglyceridemic
rats are prone to lethal arrhythmias, such as ventricular fibrillation (VF). Clinical studies
suggest that lipid-lowering drugs (statins) as well as omega-3 fatty acids (omega-3 FA)
reduce the incidence of cardiovascular diseases and sudden arrhythmic death. To elucidate the
possible cardioprotective/antiarrhythmic mechanisms we focused on intercellular channel
protein connexin-43 (Cx43), which is responsible for cell-to-cell electrical and metabolic
signals propagation. Experimental approach: Experiments were conducted on adult male
hereditary hypertriglyceridemic rats (hHTG) treated with atorvastain (0.05mg/100g b.w./day)
or fed with omega-3 FA (30mg/day) for 2 month. Myocardial expression and distribution of
Cx43 in left ventricles of treated and untreated hHTG rats was examined using cryostat
sections and immunolabeling of Cx43 with specific MAB (Chemicon, USA) followed by
quantitative image analysis. Immunohistochemistry of extracellular matrix protein,
fibronectin, was performed as well. VF inducibility was examined using Langendorff model
of isolated heart. Results showed that omega-3 FA reduced blood pressure and serum
triglycerides in hHTG rats at the same level as atorvastatin. VF inducibility was significantly
decreased due to atorvastatin or omega-3 FA treatm
moderately but significantly increased in hHTG compared to control Wistar rat heart,
regardless the treatm
junctions in control W
w
e
w
s
re
a
supported by APVV 51-059505.
55
SEX DIFFERENCES IN THE INCIDENCE OF LETHAL ARRHYTHMIAS ORRELATE WITH MYOCARDIAL CONNEXIN-43 EXPRESSION DISPARATIES.
logy, Institute for Heart Research, SAS, Bratislava, Medical Faculty of Comenius University, Bratislava, Slovak Republic
ntified sex differences in incidence of
o-cell communication ensured by gap junction
C Vladimir Knezl, Jan Drimal, Marcela Mitasikova1, Peter Weismann2, Narcis Tribulova1
Institute of Experimental Pharmaco 1
2
Background: Clinical and experimental data have ide
cardiac diseases and/or lethal arrhythmias. The cellular mechanisms responsible for these
disparities are still not fully elucidated. Cell-t
conexin-43 (Cx43) channels plays a crucial role in myocardial tissue homeostasis and
synchronisation. Therefore, we hypothesized that expression and/or distribution of Cx43 may
differ between males and females. Aim of this study was to examine both myocardial Cx43
and susceptibility of the heart to life-threatening arrhythmia, ventricular fibrillation (VF), in
non-hypertensive and hypertensive male and female rats. Methods: Experiments were
conducted on aged (>1 year-old) male and female normotensive Wistar and spontaneously
hypertensive (SHR) rats. Ventricular tissue taken from excised hearts of anesthetized rats was
immediately frozen in liquid nitrogen and processed either for in situ immuno-detection or
Western-blotting of Cx43 using mouse MAB. Susceptibility to VF was examined in isolated
heart preparation according to Langendorff using either electrical burst stimulation or
hypokalemic perfusion. Key results: Both male and female SHR rats were more vulnerable to
VF compared to Wistar counterparts. In correlation, Western-blotting of Cx43 revealed
significantly lower ventricular Cx43 expression in hypertensive than normotensive rats. In
addition, all SHR hearts exhibited abnormal myocardial distribution of Cx43, i.e. enhanced
amount of lateral, side-to-side Cx43-positive gap junctions. Female rats, both SHR and Wistar
were significantly less susceptible to VF comparing to males counterparts. It correlated with
significantly higher Cx43 expression in female comparing to male rats. Conclusions: Taken
together these findings indicate that higher level of myocardial Cx43 expression is linked with
lower lethal arrhythmia susceptibility and vice versa. This fact can explain, at least in part,
sex-related differences in incidence of life-threatening arrhythmias. Supported by VEGA
2/6064/27 and APVV 51-059505, 51-017905 grants.
56
PROTECTION AGAINST ISCHEMIA-INDUCED ARRHYTHMIAS IN THE DIABETIC HEART DOES NOT REQUIRE PI3K/AKT ACTIVATION: RELEVANCE TO ISCHEMIC PRECONDITIONING
Pharmacobiochem Lab, Fac Med
NAC 155 ± 15* 290 ± 52*
PC 195 ± 40* 88 ± 25* 77 ± 19* 151 ± 39*
<0.05 vs. non-PC control hearts conclusion, both, PC and D might induce adaptive processes in the myocardium lowering
usceptibility to antioxidant treatment. Reduced vulnerability to ischemic arrhythmias in
cutely D and preconditioned hearts does not require PI3K/Akt activation. Supported by grants
EGA SR 2/0173/08, APVV SK-CZ-0049-07 and GACR 305/07/0875
Jana Matejikova1, Jarmila Kucharska2, Jan Neckar3, Frantisek Kolar3, Dezider Pancza1, Tana Ravingerova1
21Inst Heart Res, Slovak Acad Sci & CEKVY SAS; Comenius Univ, Bratislava, SR; 3Inst Physiol, Acad Sci of the CR & Ctr Cardiovasc Res, Prague, CR Although clinical data have clearly demonstrated that diabetic patients are more prone to
ischemic heart disease, experimental data revealed controversies in response of the diabetic
(D) heart to ischemia/reperfusion (I/R). Higher tolerance to I/R injury in D heart might share
similar mechanisms with ischemic preconditioning in the normal heart, e.g., reactive oxygen
species (ROS) signaling and activation of pro-survival protein kinases. Aims were to explore
the role of phosphatidylinositol 3-kinase (PI3K)/Akt and ROS in susceptibility to ischemic
arrhythmias in hearts of 1-wk D rats (STZ 65 mg/kg, i.p.) and in normal hearts preconditioned
by 1 cycle of I/R (5 min each) before I/R. Our further goal was to characterize the effect of D
and PC on endogenous antioxidant systems. Langendorff-perfused hearts of D rats, non-
preconditioned (non-PC) and preconditioned (PC) hearts of normal rats were subjected to 30-
min occlusion of the LAD coronary artery with or without prior 15-min perfusion with
PI3K/Akt inhibitors wortmannin (W; 100 nM) and LY294002 (LY; 5 μM) or antioxidant N-
acetylcysteine (NAC; 4 mM). Levels of CoQ10, CoQ9 and α-tocopherol were measured in
left ventricular myocardium (HPLC). Total number of premature ventricular complexes
(PVC) monitored during the whole period of ischemia was significantly lower in D and PC
groups, as compared with non-PC controls (C), as well as in NAC- and LY-treated non-PC
groups. Antiarrhythmic effect in D and PC hearts was blunted by neither NAC nor PI3K/Akt
inhibition. Both, D and PC significantly increased levels of CoQ10, CoQ9 (D 19.6 ± 0.8 and
217.3 ± 9.5; PC 23 ± 2.2 and 250 ± 19 vs. 17.4 ± 0.5 and 185.0 ± 5.0 nmol/g, resp., in C;
P<0.05) and α-tocopherol (38.6 ± 0.7 and 40 ± 1 vs. 31.5 ± 2.1 nmol/g in C; P<0.01). Groups PVC (total number) C W non-PC 551 ± 61 480 ± 50
LY
D 220 ± 46* 181 ± 51* 251 ± 73* 207 ± 51*
*PIn
s
a
V
57
CALCIUM SIGNALING TO RAT HEART MITOCHONDRIA IN ACUTE DIABETES: A MEASURE FOR SALVAGE OF CARDIAC ENERGETICS
1Jana Mujkosova , Michal Cagalinec2, Miroslav Ferko1, Olga Ulicna3, Iveta
ardiovasc. Sci., SAS, Int. Laser Ctr.; Lab. Pharmacobiohem,
ation
1.) Ziegelhőffer A. et. al., Ann NY Acad Sci 967, 1-7, 2002; 2.) Waczulikova I. et al., Can J
Physiol Pharmacol 85, 372-81, 2007. Support: 2/0173/08, 2/7126/27, 1/3037/06, 1/3442/06
/2007.
Waczulikova4, Dana Kincelova4, Tana Ravingerova1, Attila Ziegelhőffer1
1Inst. Heart Res., Ctr. Excel. C 2 3
3rd Dpt. Inter. Med., Fac. Med., 4Dpt. of Nuclear Phys. and Biophys., Fac. Math., Phys., Inf., Comenius Univ., Bratislava, Slovakia
Background: Due to abnormal intracellular Ca sequestration by sarcoplasmic reticulum and
mitochondria (MIT), diabetic (DIA) heart (H) cells become strong exposed to calcium. This is
manifested by prolonged Ca-transients and by increased Ca-driven energy consumption.
However, these alterations are also accompanied with decreased trans-sarcolemmal influx of
Ca and enhanced formation of energy channels (ECH) in membranes of H MIT which yield in
partial adaptation to DIA. This indicates that measurements of physical parameters of
membranes might provide valuable additional information about capability of the H to adapt
to and cope with DIA. The present study is focused to elucidation of mutual quantitave
relationships among membrane fluidity (MF), trans-membrane potential (MP), and calcium
movements in H cells in respect to the amplitude of calcium transient (ACT) in acute DIA H.
Experimental: Adult male Wistar rats, 220±15 g b.wt.; were kept in 12L/12D regimen (22 oC) on standard pellet diet with water ad libitum. DIA was induced by streptozotocin (STZ)
65mg/kg b.wt., i.p. Experiment was terminated on the day 8 after STZ by cervical dislocation.
For control of the metabolic state of animals see (1). For cardiomyocytes, MIT preparations
and biophysical parameters see (2). Results and Discussion: MIT from DIA H exhibited
descendent MP and increased MF (p>0.05) - the latter phenomenon associated with
augmented energy transduction from MIT via an increase in number of the ECH. A
Significant negative association between MF an MP in DIA H MIT (p<0.05; r=0.67) and an
increase in ACT were also found (p=0.08). Conclusions: Prolonged duration and increased
ACT regulate the capacity of ATP delivery through the MIT membrane of DIA H. Form
of MIT ECH is coupled with decreasing of MF and MP of DIA H MIT.
APVT 51-027404, UK/399
58
EFFECT OF CHRONIC SOCIAL STRESS ON BLOOD PRESSURE AND NEUROGENIC CONTRACTIONS OF MESENTERIC ARTERY IN RATS WITH
ENETIC HYPERTENSION
he aim of this study was to investigate the effect of 8-week-lasting social stress on blood
m activity. Provinol
ese results suggest that inhibition of sympathetic activity in
ascular system of hypertensive rats exposed to crowding stress may serve as protective
echanism against marked increase of blood pressure.
upported by grants VEGA No.2/6150/27, 2/7064/27 and APVT-51-018004.
G Jozef Torok , Angelika Puzserova , Anna Zemancikova , Iveta Bernatova Institute of Normal and Pathological Physiology, Slovak Academy of Sciences and Centrum of Experimental Medicine, Bratislava, Slovak Republic T
pressure and contractile responses of isolated superior mesenteric artery to adrenergic stimuli
in normotensive Wistar, borderline hypertensive (BHR, offspring of spontaneously
hypertensive dams and Wistar sires) and spontaneously hypertensive rats (SHR). Experiments
were performed on adult 12-week-old males, which were in each phenotype randomly divided
into six groups: a/ control rats kept in groups of 4 rats/cage (480 cm2/rat); b/ stressed group (5
rats/cage, 200 cm2/rat), c/ group treated with provinol (20 mg/kg/day, 480 cm2/rat); d/ stressed
group treated with provinol (20 mg/kg/day, 200 cm2/rat); e/ group treated with low dose of
nitric oxide (NO) synthase inhibitor L-NAME (1.5 mg/kg/day, 480 cm2/rat); f/ stressed group
treated with L-NAME (1.5 mg/kg/day, 200 cm2/rat) for 8 weeks. Stress was produced by
exposure of rats to 8-week crowding with living space reduced to 200 cm2/rat. Blood pressure
was measured by tail-cuff plethysmography. Rings of isolated superior mesenteric artery were
mounted in organ baths for measurements of isometric contractile force. Neurogenic
contractions of mesenteric artery were elicited by electrical stimulation of perivascular nerves.
Social stress increased blood pressure in SHR (by 11%) and BHR (by 10%), as well as in L-
NAME-treated SHR (by 12%) and BHR (by 11%) but no differences in blood pressure were
observed in normotensive Wistar rats. Social stress did not influence contractions of
mesenteric artery to exogenous noradrenaline in all three phenotypes. However, the
magnitude of neurogenic contractions induced by endogenous noradrenaline was significantly
reduced in the mesenteric artery from stressed SHR and, at least in part, in stressed BHR. In
L-NAME-treated SHR and BHR, the decreased reactivity of mesenteric artery was restored,
suggesting that this hyporeactivity is due to an increase in the NO syste
did not influence contractions induced by exogenous noradrenaline in any of used three
phenotypes, but it reduced neurogenic contractions of mesenteric artery in control Wistar and
BHR rats and in stressed SHR. Th
v
m
S
59
REGULATION OF CARDIAC NA,K-ATPASE BY NITRIC OXIDE DURING HYPERTENSION
1Jana Vlkovicova , Veronika Javorkova1, Lucia Mezesova1, Olga Pechanova2, Norbert
Vrbjar1 1Institute for Heart Research, SAS, 2Institute of Normal and Pathological Physiology, Slovak Academy of Sciences, Bratislava, Slovakia.
The Na,K-ATPase was hypothesized to be involved in development of systemic vascular
hypertension through its effects on smooth muscle reactivity and myocardial contractility. Our
study deals with the regulatory role of nitric oxide (NO) on functional properties of the
cardiac Na,K-ATPase in three various animal models of hypertension. The first group was
represented by spontaneously hypertensive male rats (SHR) with increased activity of NO-
synthase by 60% (Sh1). The second group of SHR revealed a decreased activity of NO-
synthase by 40% (Sh2). In the third model (LN), the hypertension was induced by
administration of an inhibitor of NO-synthase, L-NAME (40mg.kg-1.day-1) resulting in
depression of NO synthesis by 72%. Studying the utilization of energy substrate ATP we
observed higher Na,K-ATPase activity in the whole concentration range of ATP for the group
Sh1. On the other hand, the Na,K-ATPase activity was depressed in Sh2 and LN groups.
Evaluation of kinetic parameters revealed increased value of Vmax by 37% and increased
affinity of the ATP binding site as indicated by the lowered Km value by 38% in group Sh1. In
the Sh2 and LN groups the Vmax was decreased by 30% and 17% respectively with no
significant change of Km value as compared to controls. During the activation with Na+ we
observed a stimulation mainly in the presence of higher concentrations of cofactor yielding
increased Vmax by 64% and increased KNa by 106% in the group Sh1. In group Sh2 we found
decreased activity in whole concentration range of NaCl resulting in decreased Vmax by 40%
and increased KNa by 38%. In the LN group the enzyme activity was significantly depressed
at lower concentrations of NaCl, showing unchanged Vmax with increased KNa by 50%. The
above data indicate a positive role of increased NO-synthesis in improvement of utilization of
ATP as well as enhanced binding of Na+ by the cardiac Na,K-ATPase. Thus the intensity of
NO synthesis may be a determining factor in regulating the functional properties of the
cardiac Na,K-ATPase.
This study was supported by Slovak Grant Agencies (grant No. VEGA 2/7127/27 and APVV-
51-059505).
60
PROTECTIVE EFFECTS OF TREATMENT WITH SIMVASTATIN AGAINST ISCHEMIA/REPERFUSION INJURY IN ISOLATED RAT HEART
ova
t of Pharmacology and Toxicology, Faculty of harmacy, Comenius University, Bratislava, Slovak Republic
Maria Zazrivcova1, Adriana Adameova2, Dezider Pancza1, Jan Styk1, Tana Ravinger 1
1Institute for Heart Research and Centre of Excellence for Cardiovascular Research of the Slovak Academy of Sciences, 2DepartmenP The inhibitors of the enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA)
reductase, which is required for cholesterol (CH) biosynthesis, or statins, are most frequently
prescribed drugs used in the primary and secondary prevention of coronary artery disease by
lowering serum levels of CH. However, statins are also known to have additional, so called
pleiotropic activity, since inhibition of HMG-CoA reductase not only prevents the synthesis
of CH, but also modulates the synthesis of other important molecules. We have previously
shown protective effects of simvastatin (S) on ischemia/reperfusion (I/R) injury in rats with
high levels of CH. The aims of the present study were to investigate the effect of treatment
with S on I/R injury in rats with normal levels of CH. Male Wistar rats were treated with
simvastatin (10 mg/kg/day, p.o.). After 5 days, experiments were performed in Langendorff-
perfused isolated hearts of S-treated rats and control non-treated animals (C). Regional
(occlusion of LAD coronary artery) or global ischemia lasted 30 min and was followed by 40-
min reperfusion. We measured ventricular arrhytmias during ischemia and 10 min of
reperfusion and recovery of contractile function (LVDP) at the end of experiment. In the S
group, the total number of ventricular premature beats during ischemia was reduced to 162 ±
62 (vs. 551 ± 61 in C; P<0.05). The total duration of the episodes of ventricular tachycardia
was significantly shorter (9.5 ± 4.1 s vs. 43.6 ± 8.6 s in C; P<0.05). In addition, severity of
reperfusion-induced arrhythmias was lower (arrhythmia severity score 2.5 ± 0.3 vs. 4.4 ± 0.5
in C; P<0.05). LVDP recovery was increased by 37.5% in the S-treated group. In conclusion,
treatment with S may confer an efficient protection against I/R injury independent of its lipid-
lowering activity. Supported by grants VEGA SR 2/0173/08, 1/4296/07
61
LIST OF PARTICIPANTS e-m l p.
a (Canada) [email protected] 33
du.pl 45 alentin Both (Slovakia)
59 arcis Tribulova (Slovakia) [email protected] 32,45,47,49,51,55,56
a Turan (Turkey) [email protected] 18 gnes Vegh (Hungary) [email protected] 26
ana Vlkovicova (Slovakia) [email protected] 27,60 lovakia) [email protected] 27,54,60
aria Zazrivcova (Slovakia) [email protected] 61 ttila Ziegelhoffer (Slovakia) [email protected] 31,52,58
aiMadhu Anand-Srivastava (Canada) [email protected] 21 Amarjit S. ArnejBarbara Bacova (Slovakia) 49 Monika Bartekova (Slovakia) [email protected] 50 Andrzej Beresewicz (Poland) [email protected] P. Czubryt (Canada) [email protected] 29 Dipak K. Das (USA) [email protected] 46 Naranjan S. Dhalla (Canada) [email protected] 38 Katarina Dlugosova (Slovakia) [email protected] 49,51,55 Andrej Dukat (Slovakia) [email protected] 40 Miroslav Ferko (Slovakia) [email protected] 31,52,58 Eva Goncalvesova (Slovakia) [email protected] 41,53 Veronika Javorkova (Slovakia) [email protected] 27,54 Philip K. Kadowitz (USA) [email protected] 23 LorrieA. Kirshenbaum (Canada) [email protected] 44 Frans H.H. Leenen (Canada) [email protected] 19 Milan Luknar (Slovakia) [email protected] 41,53 Vladimir Knezl (Slovakia) 55,56 Lucia Kolenova (Slovakia) 55 Jana Matejikova (Slovakia) [email protected] 57 Nilanjana Maulik (USA) [email protected] 12 Dennis B.McNamara (USA) [email protected] 14 Jana Mujkosova (Slovakia) [email protected] 31,52,58 Jan Murin (Slovakia) [email protected] 37 Marie Novakova (Czech Republic) [email protected] 30 Grant Pierce (Canada) [email protected] 13 Jan Styk (Slovakia) [email protected] 50,61 Ludmila Okruhlicova (Slovakia) [email protected] 34,47,49,51,55 Zoltan Papp (Hungary) [email protected] 39 Olga Pechanova (Slovakia) [email protected] 24,27,54,60 Tana Ravingerova (Slovakia) [email protected] 16,31,50,52,57,58,61 Stephen W. Schaffer (USA) [email protected] 15 Pawan K. Singal (Canada) [email protected] 36,47 Jan Slezak (Slovakia) [email protected] 36,47 Ashok Srivastava (Canada) [email protected] 25 Jozef Torok (Slovakia) [email protected] NBelmAJNorbert Vrbjar (SMA
62
63
64