DEPLETION OF PLASMA VITAMIN-C BUT NOT OF VITAMIN-E IN RESPONSE TO CARDIAC OPERATIONS

The whole-body inflammatory response produced by cardiopulmonary bypas s is an important cause of perioperative morbidity after cardiac opera tions. This inflammatory response produces reactive oxygen species and other cytotoxic substances, such as the cytokines. The generation of reactive oxygen species might deplete principal antioxidant micronutri ents, that is, vitamins C and E and the carotenoids. Therefore, we hav e investigated the time course of the plasma concentrations of vitamin s C and E and the carotenoids in 18 patients undergoing coronary bypas s operations after randomization for previous vitamin E supplementatio n (300 mg dl-alpha-acetyl-tocopherol 3 times daily for 4 weeks) or pla cebo. Supplementation with alpha-tocopherol doubled the lipid-standard ized plasma vitamin E concentration to 63.7 +/- 14.5 mu mol/L when com pared with that of the control subjects (31.2 +/- 9.0 mu mol/L) before the operation. The plasma concentrations of vitamin C (36.0 +/- 19.0 mu mol/L and 44.0 +/- 21.7 mu mol/L, respectively) and of the caroteno ids were not statistically different between the two groups at baselin e. The absolute plasma concentrations of both vitamin E and the carote noids decreased during and after cardiopulmonary bypass, but after cor rection for hemodilution the plasma concentrations of vitamin E and th e carotenoids showed no decrease. The vitamin E concentrations in the erythrocytes did not change either. In contrast, the plasma concentrat ion of vitamin C decreased in all subjects within 24 hours after the o peration by roughly 70%. Correction for hemodilution still revealed a significant decrease in plasma vitamin C that persisted in most patien ts up to 2 weeks. In conclusion, the vitamin E and the carotenoid plas ma concentrations are of no major concern during and after cardiac ope rations. In contrast, the serious depletion of vitamin C may deteriora te the defense against reactive oxygen species-induced injury during c ardiac operations.