Search

The purpose of these studies was to evaluate metabolic behavior in a 4-day reperfusion model in pigs after induction of subendocardial infarction. Two groups of swine [sham and intervention (Int) groups, n = 7) and 10 hearts per group, respectively] were prepared comparably with two surgical procedures separated over 4 days. In the Int group at the time of the first surgery, coronary flow in the left anterior descending (LAD) circulation was partially restricted (by 60%) for 60 min and was then reperfused. LAD myocardium at the time of the second surgery in both groups was extracorporeally perfused aerobically (5.9 +/- 0.2 ml.min-1.g dry wt-1) for 60 min and infused by equilibrium labeling with [U-14C]-palmitate and [5-3H]glucose to estimate fatty acid oxidation and exogenous glucose utilization. During extracorporeal perfusion, regional myocardial shortening and oxygen consumption were comparable between groups despite a marginal impairment in ATP resynthesis by mitochondria (26% decrease, P < 0.071) in Int hearts and a significant decline in mitochondrial respiration (45% decrease in respiratory control rate, P < 0.008; and 41% decrease in state 3 respiration, P < 0.032) as compared with sham hearts. Fatty acid oxidation described by 14CO2 production was 34.00 +/- 4.72 mumol.h-1.g dry wt-1 (averaged from 30-60 min of perfusion) in sham hearts but was decreased (by 48%, P < 0.004) in Int hearts. This reduction in fatty acid utilization may in part be explained by declines in the observed activity of the mitochondrial membrane transporter enzyme, carnitine palmitoyltransferase.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-chain fatty acyl-CoA esters (LCFACoAE) were extracted from freeze-clamped powdered brown adipose tissue (BAT) obtained from thermoneutral control and cold-acclimated hamsters and the CoA esters individually separated by high-performance liquid chromatography. LCFACoAE of carbon chain length C12 to C20 were identified by increasing column retention time in the following order: C12:0, C14:1, C14:0, C16:1, C18:2, C16:0, C18:1, C18:0, and C20:4. The mean total LCFACoAE concentrations were 235 +/- 40 nmol/g protein for the control hamsters and 648 +/- 105 nmol/g protein for the 22-day cold-acclimated hamsters. A rapid fourfold increase in the levels of C16:0, C18:0, and C18:1 occurred within hours after initiation of the cold temperature, whereas the concentrations of the other six LCFACoAE either increased only slightly or remained unchanged. Almost 50% of the total LCFACoAE in the BAT of cold-acclimated hamsters was made up of C16:0, C18:0, and C18:1. These results, which demonstrate some dynamic changes in adipose tissue LCFACoAE, are consistent with their proposed role in the initiation and maintenance of BAT thermogenesis.