Lowering the degree of alcohol in red wine does not alter its cardioprotective effect

Lowering the degree of alcohol in red wine does not alter its cardioprotective effect

ABSTRACTS / Journal of Molecular and Cellular Cardiology 40 (2006) 920 – 1015 S68 additive with that induced by forskolin. Phosphorylation of S63 by ...

71KB Sizes 2 Downloads 18 Views

ABSTRACTS / Journal of Molecular and Cellular Cardiology 40 (2006) 920 – 1015

S68 additive with that induced by forskolin. Phosphorylation of S63 by ET-1 was not influenced by pretreatment with forskolin. Therefore, PKA activation does not phosphorylate all PLM in the cell: a second pool is phosphorylated only upon PKC activation. Since prephosphorylation of S68 inhibits S63 phosphorylation by PKC, the population of PLM phosphorylated at S63 following ET-1 treatment is not phosphorylated at S68. Hence, PKA and PKC may have access to different cellular pools of PLM. doi:10.1016/j.yjmcc.2006.03.225

211. Differential distribution of mouse cardiac Na/K ATPase A1 and A2-subunit function in T-tubule and surface sarcolemmal membranes Roger G. Berry a, William Fuller a, Sanda Despa b, Donald M. Bers b, Michael J. Shattock a. a Cardiovascular Division, King’s College London, The Rayne Institute, St Thomas’ Hospital, London, UK. b Department of Physiology, Loyola University Chicago, Maywood, IL, USA Cardiac Na/K ATPase (NKA) is the essential mechanism by which intracellular Na concentration is regulated. This in turn affects intracellular Ca and cardiac contractility via Na/Ca exchange. The a-catalytic a-subunit contains binding sites for Na+, K+, ATP and ouabain. a1 and a2-subunit isoforms are expressed in adult mouse heart and may have distinct functional roles and differential subcellular localisation in Ttubule (TT) vs. surface sarcolemmal (SSL) membranes. Here we have assessed the functional distribution of a1- and a2-NKA in TT vs. SSL membranes by formamide-induced detubulation of mouse ventricular myocytes and measurement of NKA current (I pump). Ouabain-dependent I pump inhibition in control myocytes revealed a high affinity NKA isoform (Ia2, K 1/2 = 0.26 T 0.11 mmol/L) that accounted for 12.1% of I pump and a low affinity isoform (Ia1, K 1/2 = 104.8 T 5.6 mmol/L) which contributed the remaining 87.9 T 1.2%. Following myocyte detubulation, Ia2 accounted for only 6.24% of I pump. Detubulation also reduced cell capacitance (181 T 12 to 127 T 17pF) and I pump density from 1.42 T 0.1 (control) to 1.20 T 0.04pA/pF (SSL). Although TT membranes represent only 30% of total surface area, ¨70% of Ia2 and ¨37% of Ia1 are resident there. Ia1 density was substantially higher than Ia2 in SSL (Ia1:Ia2 = 16:1). In TT, the dominance of Ia1 over Ia2 was markedly reduced (Ia1:Ia2 = 4:1). Total NKA density was ¨60% higher in TT (1.94 pA/pF, derived) compared to SSL membranes, due to ¨27% (1.38-fold) higher Ia1 and ¨82% (5.57-fold) higher Ia2 density in the TTs. Further work is required to determine whether differential -subunit localisation is associated with distinct functional roles. doi:10.1016/j.yjmcc.2006.03.226


212. Regulation of cardiac Na/K ATPase by FXYD1 (phospholemman) Roger G. Berry, William Fuller, Michael J. Shattock. Cardiovascular Division, King’s College London, The Rayne Institute, St Thomas’ Hospital, London, UK Phospholemman (PLM) is a member of the FXYD family of low molecular weight proteins which are tissue-specific regulators of Na/K ATPase (NKA). We have used PLM knockout (KO) and wild-type (WT) mice to investigate the role of PLM in regulating the electrophysiological characteristics of cardiac NKA. Extracellular potassium (K) and intracellular sodium (Na) activation curves were constructed by measuring whole-cell K-sensitive NKA-mediated current (I pump) in the perforatedpatch conformation. Maximal pump current (V max) was increased by 20 –30% in PLM-KO myocytes compared to WT controls, NKA Na affinity elevated by ¨35% (K1/2 Na at 0 mV = 21.7 and 33.9 mmol/L respectively) and NKA a and h subunit expression reduced by ¨36%. Normalizing for equal subunit expression suggests that maximal unitary NKA pump rate is ¨double in PLM-KO myocytes. In PLM-WT myocytes, 10 Amol/L isoproterenol (ISO) increased V max by ¨17% (from 1.91 to 2.23 pA/pF) and NKA Na affinity by ¨15% (from 33.5 to 28.6 mmol/L). V max stimulation was exclusively due to stimulation of a1mediated I pump. Immunoblotting with phospho-specific antibodies demonstrated that ISO-induced potentiation of I pump directly mirrors elevated PLM phosphorylation at serine 68. ISO had no effect in PLM-KO myocytes. We conclude that PLM modulates cardiac NKA by acting as a brake on its activity, achieved by limiting maximal pump turnover rate and intracellular Na affinity. PKA-mediated PLM phosphorylation increases both V max and Na affinity in a qualitatively similar manner to the genetic knockout of PLM. doi:10.1016/j.yjmcc.2006.03.227

213. Lowering the degree of alcohol in red wine does not alter its cardioprotective effect Sandrine Lecour a, Diane Blackhurst b, David Marais b, Lionel Opie a. a Hatter Institute, London, UK. b Division of Lipidology, University of Cape Town, South Africa Introduction: Many epidemiological, clinical and basic studies have provided evidence of the benefit of moderate red wine consumption in cardiovascular health. It has been suggested that both alcoholic content and polyphenols/ flavonoids in the red wine may contribute to this cardioprotective effect. Here, we compared the antioxidant and cardioprotective properties of a French red wine (Cabernet Sauvignon, 12% alcohol by volume) with the same wine that was subjected to reverse osmosis for partial removal of the alcohol content (Lir, 6% alcohol by volume).


ABSTRACTS / Journal of Molecular and Cellular Cardiology 40 (2006) 920 – 1015

Methods: Antioxidant capacity of the beverages was assessed in vitro using the Oxygen Radical Absorbance Capacity (ORAC) assay technique. To test the cardioprotective effect of wine and Lir, the drinking water of Long Evans male rats used for controls was supplemented by red wine (12%) or Lir (6%). After 10 days of treatment, hearts were isolated on a Langendorff system and subjected to 30 min global ischemia followed by 30 min of reperfusion (I/R). Results: No differences in antioxidant capacity were observed in vitro between the wine and the Lir (30.6 T 0.9 mmol/l Trolox equivalent and 30.4 T 0.9, respectively, ns) (n = 8). Control hearts subjected to I/R presented a rate pressure product (expressed as a percentage of baseline value) of 16 T 4%. Pre-treatment with wine or Lir improved the rate pressure product to 40 T 6 and 43 T 6%, respectively (P < 0.05 vs. control). Conclusion: Our findings suggest that the reduction of alcohol content to 6% in the wine (as found in the Lir) did not alter its antioxidant and cardioprotective properties. doi:10.1016/j.yjmcc.2006.03.228

214. Induction of cellular apoptosis in h9c2 cells by tissue factor G.A. Frentzou, C. Ettelaie, A.-M.L. Seymour. Department of Biological Sciences, University of Hull, Hull, HU6 7RX, UK Cardiac hypertrophy is the adaptive response of the heart to chronic mechanical overload and an important risk factor in the development of heart failure. Increased cell death resulting from both apoptosis and necrosis is a characteristic of cardiac hypertrophy. During the onset of cardiac hypertrophy, tissue factor (TF), the main initiator of blood coagulation, is shown to be up-regulated in the myocardium. TF is a strong marker and putative modulator of cellular events in apoptosis. In the present study, we investigated the involvement of TF in the programmed cell death of H9c2 cardiomyocytic cell line. H9c2 cardiomyocytes were cultured in serum-free conditions and treated with a range of concentrations of human recombinant TF (0.05 –2 AM) over a period of 10 days. The proliferation of the cells was assessed by an MTT assay and the onset of apoptosis measured by caspase-3 activation using flow cytometry. Treatment of H9c2 cells over the period of the investigation resulted in a progressive decrease in the H9c2 proliferation (down to 20% of the control). Caspase-3 activity was increased above 12% of the control over the period of the investigation. We propose that chronic elevation in circulating TF, as a result of infection or vascular inflammation, can lead to myocyte depletion, ultimately leading to cardiac hypertrophy. doi:10.1016/j.yjmcc.2006.03.229

215. Novel injectable alginate scaffold attenuates progressive infarct expansion and preserves left ventricular systolic and diastolic function late after myocardial infarction Natalie Landa a, Micha S. Feinberg a, Radka Holbova a, Liron Miller a, Smadar Cohen b, Jonathan Leor c. a Tel Aviv University, Tel-Hashomer, Israel. b Ben Gurion University, BeerSheva, Israel. c Tel Aviv University, Tel-Hashomer, Israel Background: Cessation or reversal of progressive left ventricular (LV) dysfunction is a major aim of heart failure therapy. We developed a cross-linked concentrated alginate solution, which upon solidification in tissue becomes a hydrogel. The aim of the present study was to test the hypothesis that an injection of this novel alginate solution mimicking the extracellular matrix (ECM) into an old scar tissue, late after myocardial infarction (MI), will provide physical and biological scaffolding, will promote tissue rejuvenation and will prevent progressive LV dysfunction. Methods and results: Rats (n = 40) were subjected to extensive anterior myocardial infarction (MI). Two months later, the survivors were randomized to injection of alginate solution (n = 15) or PBS (control, n = 12) into myocardial scar. Four months after MI and two months after injection, postmortem morphometric analysis and histological examination of the hearts revealed that alginate solution injection increased scar thickness (2.79 T 0.27 cm vs. 1.63 T 0.31 cm; P = 0.01) and significantly reduced expansion index (0.56 T 0.08 vs. 1.05 T 0.26; P < 0.0001), as compared with controls. Serial echocardiography studies showed that alginate solution injection attenuated the progressive deterioration in LV fractional shortening, as compared with control (12 T 6% vs. 37 T 9%; P < 0.05). Anterior wall diastolic and systolic thickness were markedly increased in alginate-treated hearts (25 T 4.5% vs. 7 T 6.7%; P = 0.03, and 31 T 6.2 % vs. 3 T 6.8%; P = 0.006, respectively). Furthermore, while control animals developed restrictive LV filling pattern, as assessed by Doppler echocardiogram, diastolic function improved in alginate-treated hearts (E/A wave ratio of 1.73 T 0.09 for alginate vs. 3.34 T 0.5 for control; P < 0.0001). Conclusions: Our work shows, for the first time, that injection of in situ gelling solution of crossed-link alginate into an old scar tissue provides physical and biological scaffolding, and preserves LV systolic and diastolic function. Our work enables a minimally invasive, catheter-based, acellular option to repair old scar tissue and to prevent heart failure. doi:10.1016/j.yjmcc.2006.03.230

216. Does insulin mediate cardiac protection via cAMP? J. Lopes, B. Huisamen, A. Lochner. Department of Biomedical Sciences, Faculty of Health Sciences, University of Stellenbosch, Tygerberg, South Africa Recent studies suggested that insulin per se protect the heart during ischemia, which we confirmed using a model of low flow ischemia [LFI]. Elevated levels of cAMP are