Bashir M. Matata

Off-pump bypass graft operation significantly reduces oxidative stress and inflammation

BACKGROUNDnThis study investigated whether off-pump coronary bypass graft operations on the beating heart under normothermic conditions reduces the systemic oxidative stress and inflammatory reaction seen in patients operated under cardiopulmonary bypass (CPB).nnnMETHODSnA cardiac stabilizer (Octopus Tissue Stabilizer; Medtronic Inc, Minneapolis, MN) was used to perform the coronary anastomoses on the normothermic beating heart with or without CPB. Serial blood samples were taken at various intervals. Plasma was analyzed for several oxidative stress and inflammatory markers.nnnRESULTSnSignificant increases from prior anesthesia values of lipid hydroperoxides (190% at 4 hours), protein carbonyls (250% at 0.5 hours) and nitrotyrosine (510% at 0.5 hours) were seen in the CPB group, but they were abolished or significantly reduced in the off-pump group. Complement C3a and elastase levels were rapidly increased upon the institution of CPB, and this was followed by increases in IL-8, TNF-alpha, and sE-selectin. In contrast, the rise of these factors was blunted in patients operated without CPB.nnnCONCLUSIONSnOff-pump coronary bypass graft operation on a beating heart significantly reduces oxidative stress and suppresses the inflammatory reaction associated with the use of CPB.

Protein nitration is predominantly mediated by a peroxynitrite-dependent pathway in cultured human leucocytes

Protein nitration is a common characteristic of oxidative injury caused by the invasion of leucocytes into inflammatory lesions. Two distinct pathways of nitration of protein tyrosine residues, namely the peroxynitrite (ONOO(-))-mediated pathway and another catalysed by the haem-containing peroxidases, have been reported under experimental conditions. However, the contribution of these two pathways in human leucocytes is still controversial. The present study demonstrates that the process of phenolic nitration of proteins in cultured human leucocytes is mainly ONOO(-)-mediated and that it differs between granulocytes and mononuclear cells, depending on the cell compartment and the stimuli. We have also shown that NO induces protein nitration via a ONOO(-)-dependent pathway, whereas NO(2)(-), the NO metabolite, does not increase but decreases nitration in PMA-stimulated leucocytes. The inhibition of myeloperoxidase activity did not reduce protein nitration; on the other hand, the myeloperoxidase inhibitor aminobenzoic hydrazide caused increased nitration, which was mediated by ONOO(-). These results suggest that protein nitration is predominantly mediated by a ONOO(-)-dependent pathway in cultured human leucocytes and that the myeloperoxidase-catalysed pathway does not play a significant role in protein nitration.

Ethnic Differences in the Management of Coronary Heart Disease Patients: Lessons to Be Learned in Indo-Asians

Objectives: To examine the impact of ethnicity on the outcome of coronary artery bypass grafting (CABG) for myocardial revascularization. Subjects and Methods: We evaluated retrospectively 7,226 Caucasian (CC) and 650 Indo-Asian (IA) patients who underwent isolated first-time CABG surgery over 5 years. The relationship between ethnicity (IA vs. CC) and 30-day mortality, 6-month mortality and complications were analysed. Results: After adjustment for baseline characteristics, IA and CC patients had similar 30-day [IA/CC odds ratio (OR) 1.07; 95% confidence interval (CI) 0.84–1.35; p = 0.59] and 6-month mortality risk (IA/CC OR 1.10; 95% CI 0.91–1.34; p = 0.31). However, IA patients were more likely to experience complications following surgery (OR 1.28; 95% CI 1.14–1.45; p < 0.01). Conclusion: Ethnicity does not appear to be a strong risk factor for adverse outcomes following CABG surgery in the IA patients. However, future studies are needed to elucidate the specific reasons for higher complication rates in IA patients and to devise strategies to reduce complications following the operation for these patients.