INFLUENCE OF HEPATIC MITOCHONDRIAL REDOX STATE ON COMPLEMENT BIOSYNTHESIS AND ACTIVATION DURING AND AFTER CARDIOPULMONARY BYPASS OPERATIONS

We have proposed the hazardous phenomena associated with cardiopulmona ry bypass (CPB) are due to metabolic derangement by hepatic mitochondr ial dysfunction during and after CPB. On the contrary, complement acti vation and consumption during CPB is reported to be related to the mor bidity associated with cardiac surgery. To determine the significance of the hepatic mitochondrial function on the morbidity of cardiac surg ery, we measured the serum levels of complements (C3 and C4), activate d complements (C3a and C4a), and the arterial ketone body ratio (AKBR) , which reflects the hepatic mitochondrial redox state, in 30 patients undergoing CPB. The AKBR, which was at a normal level preoperatively, dropped to a critical level after the initiation of CPB and remained at a low level during the CP8, returning to the preoperative level on the second postoperative morning in a time dependent fashion. The pati ents group were assigned to two groups according to their AKBR on the first postoperative morning. Group I consisted of patients whose AKBR had recovered to above 0.7 on the first postoperative morning (n=16). Group II consisted of the rest of the patients (n=14). The serum compl ement concentration had considerably decreased by the end of bypass, b ut recovered in a time-dependent fashion after CPB, The group I patien ts (C3: 71% of its preoperative value, C4: 85% of its preoperative val ue) recovered their complements more quickly than the group II patient s (C3: 56% of its preoperative value, C4: 54% of its preoperative valu e). However, the serum C3a and C4a concentrations increased by the end of bypass (C3a: 806% of its preoperative value, C4a: 341% of its preo perative value). The activated complements were significantly higher i n the group II patients (C3a: 124% of its preoperative value, C4a: 236 % of its preoperative value) than in the group I patients (C3a: 75% of its preoperative value, C4a: 113% of its preoperative value) on the f irst postoperative morning. It is suggested that hepatic mitochondrial function is related to recovering the complements and to reducing the activated complements after CPB.