Carnitine supplementation improves myocardial function in hearts front ischemic diabetic and euglycemic rats

Background. Nonischemic myocardial dysfunction in patients with diabetes me llitus appears to be attenuated with long-term L-carnitine therapy. The eff ect of acute L-carnitine supplementation on rat hearts from euglycemic and diabetic animals subjected to ischemia and reperfusion is investigated in t his study. Methods. Study rats had diabetes mellitus induced by streptozocin (65 mg/kg intraperitoneally), and control rats had injection of saline solution (n = 12 per group). About 1 month later, the hearts were suspended on a Langend orff: apparatus and perfused with either standard buffered Krebs-Henseleit solution or this standard solution supplemented with L-carnitine (5 mmol/L) . After stabilization, normothermic, zero-now ischemia was instituted for 2 0 minutes followed by 60 minutes of reperfusion. There were four study grou ps (n = 6 per group): hearts that were from euglycemic rats and that were p erfused with standard buffered Krebs-Henseleit solution (E-STD); hearts tha t were from diabetic animals and that were perfused with the same standard buffered solution (DM-STD); hearts taken from diabetic animals and perfused with L-carnitine-enriched solution (DM-CAR); and hearts taken from euglyce mic rats and perfused with the enriched solution (E-CAR). Results. At 60 minutes of reperfusion, left ventricular developed pressure was significantly better in hearts from both groups (diabetic and euglycemi c) with carnitine supplementation (DM-CAR versus DM-STD and E-CAR versus E- STD, p < 0.01 for both, by analysis of variance). Left ventricular end-dias tolic pressure was significantly lower in the DM-CAR group compared with ai l other groups (p < 0.01 by analysis of variance). Conclusions. These findings suggest that acute L-carnitine supplementation significantly improves the recovery of the ischemic myocardium in diabetic and euglycemic rats. (C) 1998 by The Society of Thoracic Surgeons.