Beneficial effect of prolonged heme oxygenase 1 activation in a rat model of chronic heart failure.

We and others have previously demonstrated that heme oxygenase 1 (HO-1) induction by acute hemin administration exerts cardioprotective effects. Here, we developed a rat model of heart failure to investigate whether a long-term induction of HO-1 by chronic hemin administration exerted protective effects. Sprague Dawley rats that underwent permanent ligation of the left coronary artery were closely monitored for survival rate analysis and sacrificed on day 28 post-operation. Administration of hemin (4 mg/kg body weight) every other day for 4 weeks induced a massive increase in HO-1 expression and activity, as shown by the increased levels of the two main metabolic products of heme degradation, bilirubin and carbon monoxide (CO). These effects were associated with significant improvement in survival and reduced the extension of myocardial damage. The ischemic hearts of the hemin-treated animals displayed reduced oxidative stress and apoptosis in comparison with the non-treated rats, as shown by the decreased levels of lipid peroxidation, free-radical-induced DNA damage, caspase-3 activity and Bax expression. Besides, chronic HO-1 activation suppressed the elevated levels of myeloperoxidase (MPO) activity, interleukin 1ß (IL-1ß) production and tumor necrosis factor-α (TNFα) production that were evoked by the ischemic injury, and increased the plasma level of the anti-inflammatory cytokine IL-10. Interestingly, HO-1 inhibitor zinc protoporphyrin IX (ZnPP-IX; 1 mg/kg) lowered bilirubin and CO concentrations to control values, thus abolishing all the cardioprotective effects of hemin. In conclusion, the results demonstrate that chronic HO-1 activation by prolonged administration of hemin improves survival and exerts protective effects in a rat model of myocardial ischemia by exerting a potent antioxidant activity and disrupting multiple levels of the apoptotic and inflammatory cascade.

Use of antidepressant serotoninergic medications and cardiac valvulopathy: a nested case-control study in the health improvement network (THIN) database.

AIMS: To quantify the risk of cardiac valvulopathy (CV) associated with the use of antidepressant serotoninergic medications (SMs). METHODS: We conducted a case-control study nested in a cohort of users of antidepressant SMs selected from The Health Improvement Network database. Patients who experienced a CV event during follow-up were cases. Cases were ascertained in a random sample of them. Up to 10 controls were matched to each case by sex, age, month and year of the study entry. Use of antidepressant SMs during follow-up was defined as current (the last prescription for antidepressant SMs occurred in the 2 months before the CV event), recent (in the 2-12 months before the CV event) and past (>12 months before the CV event). We fitted a conditional regression model to estimate the association between use of antidepressant SMs and the risk of CV by means of odds ratios (ORs) and corresponding 95% confidence intervals (CIs). Sensitivity analyses were conducted to test the robustness of our results. RESULTS: The study cohort included 752,945 subjects aged 18-89 years. Throughout follow-up, 1663 cases (incidence rate: 3.4 per 10,000 person-years) of CV were detected and were matched to 16,566 controls. The adjusted OR (95% CI) for current and recent users compared with past users of antidepressant SMs were 1.16 (0.96-1.40) and 1.06 (0.93-1.22), respectively. Consistent effect estimates were obtained when considering cumulative exposure to antidepressant SMs during follow-up. CONCLUSIONS: These results would suggest that exposure to antidepressant SMs is not associated with an increased risk of CV.