Effect of N-acetylcysteine in attenuating ischemic reperfusion injury in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass.

Ischemic reperfusion injury due to oxidative stress remains one of the challenging problems during cardiac surgeries. The imbalance in the production of free radicals and antioxidants in vivo determines the extent of oxidative stress. The use of antioxidants in cardioplegia has become an important strategy to salvage the myocardium from the attack of these radicals. The objective of this study was to analyze the cardioprotective effect of N-acetylcysteine (NAC) on early reperfusion injury in patients undergoing coronary artery bypass grafting using biochemical markers. Fifty-three patients with left ventricular ejection fraction >0.4 scheduled for coronary artery bypass grafting with cardiopulmonary bypass were selected and divided into two groups. The first group of patients (n=25) received isothermic cardioplegia alone, whereas the second group of patients (n=28) received cardioplegia enriched with NAC (50mg/kg body weight). The free radicals, antioxidants, cardiac troponin I, and hemodynamic and clinical properties of the patients were preoperatively and postoperatively evaluated at five different time intervals. Malondialdehyde level as a measure of free radicals was significantly lower in the NAC-enriched group during reperfusion (p<0.05) and after 12 hr (p<0.05) and 24hr (p<0.001) of surgery. All the antioxidants were elevated in the test group during the reperfusion period (p<0.01). A significant improvement (p=0.001) in the postoperative ejection fraction was noted in the test group. No significant differences were observed between the groups in the level of cardiac troponin I (p=not significant). The use of NAC in patients undergoing coronary artery bypass grafting using cardiopulmonary bypass decreased oxidative stress substantially. However, it did not lead to improvement in the level of cardiac troponin I, a marker of myocardial injury, in our study. Hence, the cardioprotective effect of NAC and the adaptation of the myocardium to oxidative stress should be extensively studied.

Disease modifying effect of statins in dextran sulfate sodium model of mouse colitis.

OBJECTIVE: We evaluated the disease modifying effect of simvastatin and atorvastatin in Dextran Sulfate Sodium (DSS) model of colitis. MATERIALS AND METHODS: Thirty, 8-week old female Swiss-Webster mice were separated into 5 groups (n = 6/group). Colitis was induced by feeding 4 % DSS solution for 7 days. Following discontinuation of DSS, over the next 7 days, the groups orally received simvastatin (20 mg/kg/day), atorvastatin (60 mg/kg/day), vehicle only (0.75 % methylcellulose), subcutaneous 30 mug injections of anti-TNFalpha monoclonal antibody or intraperitoneal anti-mouse apolipoprotein A-I antibody respectively. Disease activity Index (DAI) was determined daily by a blinded investigator. RESULTS: The mean reduction in DAI scores from day 7 to day 14 for anti-TNFalpha group, simvastatin and atorvastatin group were 74 %, 76 % and 64 %, respectively as compared to 41 % reduction in vehicle and anti-apolipoprotein A-I antibody-treated groups. CONCLUSIONS: This finding suggests that statins may have the ability to modify the disease activity in the DSS model of colitis and the disease modifying effect is comparable to anti-mouse TNFalpha treatment in this model.