Correlation between long-chain acylcarnitine in serum and myocardium after heart transplantation in humans

The concentrations of free, short-chain, and long-chain acylcarnitine were determined in 19 right ventricular endomyocardial biopsies and in serum from 14 patients after orthotopic heart transplantation and 3 nontransplanted control patients with normal cardiac function. Coronary angiography was normal in all patients. Left ventricular ejection fraction as measured by radionuclide ventriculography was not different between heart-transplanted and control patients (60.3 +/- 6.7% and 61.7 +/- 10.7%, respectively). Myocardial and serum carnitine concentrations in heart-transplanted patients were not different from control patients (myocardium: free carnitine 11.8 +/- 4.8 vs 7.1 +/- 7.1, short-chain acylcarnitine 4.5 +/- 2.1 vs 5.8 +/- 2.0, long-chain acylcarnitine 4.9 +/- 3.8 vs 3.9 +/- 3.2 mumol/g noncollagen protein; serum: free carnitine 32.6 +/- 11.2 vs 32.0 +/- 9.9, short-chain acylcarnitine 7.3 +/- 5.2 vs 5.1 +/- 1.3, long-chain acylcarnitine 4.1 +/- 2.7 vs 4.8 +/- 4.0 mumol/L). There was a highly significant correlation between myocardial and serum long-chain acylcarnitine (r = 0.76, P < 0.001). The data suggest that carnitine metabolism is not altered after heart transplantation.