PH (pulmonary hypertension) often complicates the disease course of patients with COPD (chronic obstructive pulmonary disease) and is an indication of a worse prognosis. In the present study, we assessed whether pravastatin administration was effective in improving PH and exercise capacity in COPD patients with PH, and whether the pulmonary protection was mediated by inhibiting ET-1 (endothelin-1) production. In a double-blind parallel design, 53 COPD patients with PH were randomly assigned to receive either placebo or pravastatin (40 mg/day) over a period of 6 months at a medical centre. Baseline characteristics were similar in both groups. The exercise time remained stable throughout the study in the placebo group. After 6 months, the exercise time significantly increased 52% from 660+/-352 to 1006+/-316 s (P<0.0001) in pravastatin-treated patients. With pravastatin, echocardiographically derived systolic PAP (pulmonary artery pressure) decreased significantly from 47+/-8 to 40+/-6 mmHg. There was significant improvement in the Borg dyspnoea score after administering pravastatin. Despite unchanged plasma ET-1 levels throughout the study, urinary excretion of the peptide was decreased and significantly correlated with an improvement in exercise time in pravastatin-treated patients (r=-0.47, P=0.01). In conclusion, pravastatin significantly improved exercise tolerance, and decreased PH and dyspnoea during exercise in COPD patients with PH, probably by inhibiting ET-1 synthesis.

Lee T-M, Lin M-S, Chang N-C. Inhibition of histone deacetylase on ventricular remodeling in infarcted rats. Am J Physiol Heart Circ Physiol 293: H968-H977, 2007. First published March 30, 2007; doi:10.1152/ajpheart.00891.2006.-Histone deacetylase (HDAC) determines the acetylation status of histones and, thereby, controls the regulation of gene expression. HDAC inhibitors have been shown to inhibit cardiomyocyte growth in vitro and in vivo. We assessed whether HDAC inhibitors exert a beneficial effect on the remodeling heart in infarcted rats. At 24 h after ligation of the left anterior descending artery, male Wistar rats were randomized to vehicle, HDAC inhibitors [valproic acid (VPA) and tributyrin], an agonist of HDAC (theophylline), VPA ϩ theophylline, or tributyrin ϩ theophylline for 4 wk. Significant ventricular hypertrophy was detected as increased myocyte size at the border zone isolated by enzymatic dissociation after infarction. Cardiomyocyte hypertrophy and collagen formation at the remote region and border zone were significantly attenuated by VPA and tributyrin with a similar potency compared with that induced by the vehicle. Left ventricular shortening fraction was significantly higher in the VPA-and tributyrin-treated groups than in the vehicle-treated group. Increased synthesis of atrial natriuretic peptide mRNA after infarction was confirmed by RT-PCR, consistent with the results of immunohistochemistry and Western blot for acetyl histone H4. The beneficial effects of VPA and tributyrin were abolished by theophylline, implicating HDAC as the relevant target. Inhibition of HDAC by VPA or tributyrin can attenuate ventricular remodeling after infarction. This might provide a worthwhile therapeutic target.hypertrophy; infarction HISTONE ACETYLATION PLAYS a critical role in cardiac development and disease. Acetylation of histone residues results in unwinding of the DNA, which allows transcription factors and RNA polymerase II to bind more readily to DNA and, thereby, increase gene transcription (40). Histone deacetylase (HDAC) inhibitors have been shown to cause cell cycle arrest. Class I and II HDACs are involved in the control of cardiac hypertrophy (4,16,40). Class I HDACs can be recruited by homeodomain-only protein or other hypertrophic stimuli, resulting in inhibition of serum response factor and the antihypertrophic gene program (16). Class II HDACs can act as signal-responsive repressors of cardiac hypertrophy by inhibiting expression of the gene that is dependent on myocyte enhancer factor 2C (4, 40). Consistent with this repressive role, mutant mice lacking the class II HDAC9 are hypersensitive to hypertrophic signals (26, 40). Paradoxically, HDAC inhibitors such as valproic acid (VPA) (33) and tributyrin induce growth arrest, differentiation, and/or apoptosis of cardiomyocytes in vitro (3). These inhibitory effects are believed to be caused, in part, by accumulation of acetylated proteins, such as nucleosomal histones, which appear to play a major role in regulation of transcription of ge...

Diabetic patients are more prone to develop postinfarction complications. It remained unclear whether diabetes mellitus- or sulfonylureas-associated changes of ATP-sensitive potassium (K(ATP)) channels, an integral player in ischemic preconditioning, are responsible for the increased mortality. The purpose of this study was to determine the impact of diabetes mellitus per se and different sulfonylurea administration on cardioprotective effects in diabetic patients undergoing coronary angioplasty. Myocardial ischemia after coronary angioplasty was evaluated in 20 nondiabetic and 23 diabetic patients chronically taking either glibenclamide or glimepiride. Nondiabetic patients treated with glimepiride significantly lowered the ischemic burden assessed by an ST-segment shift, chest pain score, and myocardial lactate extraction ratios compared with the glibenclamide-treated patients, implying that acute administration of glimepiride did not abolish cardioprotection. In the diabetic glibenclamide-treated group, the reduction in the ST-segment shift afforded by nicorandil in the first inflation (-58% vs. the first inflation in the glibenclamide group alone) was similar to that afforded by preconditioning (-59% during the second vs. the first inflation). In glimepiride-treated groups, the magnitude of attenuated lactate production was less in diabetes than that in nondiabetes at the second inflation, suggesting that diabetes mellitus per se plays a role in determining lactate production. Our results show that both diabetes mellitus and sulfonylureas can act in synergism to inhibit activation of K(ATP) channels in patients undergoing coronary angioplasty. The degree of inhibition assessed by metabolic and electrocardiographic parameters is less severe during treatment with glimepiride than with glibenclamide. Restitution of a preconditioning response in glimepiride-treated patients may be the potential beneficial mechanism.

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Background-The ischemic preconditioning response among elderly patients is known to be lower than in adult patients.Since mitochondrial ATP-sensitive potassium (K ATP ) channels exert preconditioning effects, we undertook this study to determine whether this attenuated activation of K ATP channels influences the reduced responsiveness of elderly patients to ischemic preconditioning. Methods and Results-Fifty-six patients undergoing angioplasty for a major epicardial coronary artery were randomly allocated to either an ischemic preconditioning group, a nicorandil (an agonist of K ATP channels) group, or a glibenclamide (an antagonist of K ATP channels), group based on their age: adult groups (nϭ26; age, Յ55 years; mean age, 45Ϯ5 years) and elderly groups (nϭ30; age, Ն65 years; mean age, 71Ϯ3 years). Ischemic preconditioning with a 120-second coronary occlusion significantly lowered the ischemic burden assessed by ST-segment shift, chest pain score, and myocardial lactate extraction ratios in the adult group. This did not occur in the elderly group. The impaired preconditioning responsiveness in the elderly patients was reversed by nicorandil administration or an ischemic period lengthened to 180 seconds. However, nicorandil-induced cardioprotection was abolished by administering glibenclamide in both the adult and elderly groups. Conclusions-The present study demonstrates that preconditioning significantly enhances the tolerance of the heart to subsequent ischemia in adults but not in senescent patients. Since prolonged ischemia and nicorandil are able to mimic preconditioning and can reverse impaired responsiveness, impaired preconditioning of the aged heart appears to be due to an attenuated activation of K ATP channels.

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SSHL may confer an independent risk of MI. This observation may prompt the early detection and timely treatment of patients at a high risk of MI.