Long-term effect of acetyl-L-carnitine on myocardial 123I-MIBG uptake in patients with diabetes.
Carnitine derivatives may have beneficial effects on cardiac and nerve function in patients with diabetes. The aim of this study was to investigate the effect of acetyl-L-carnitine (ALC) on myocardial sympathetic nervous function as measured with 123I-meta-iodobenzyl guanidine (MIBG) and single-photon emission tomography (SPET) in 19 patients with diabetes (placebo group, n = 6; ALC group, n = 13) at the beginning and at the end of a 1-year randomized, placebo-controlled, double-blind trial. The coefficient of variation for the MIBG analysis was 4%. In patients who were given a placebo, global myocardial MIBG uptake deteriorated during the study (MIBG uptake 1-year follow-up/baseline, 0.86 +/- 0.05, mean +/- standard error of mean), whereas in patients treated with ALC, MIBG uptake did not change significantly (1-year follow-up/baseline, 1.07 +/- 0.08; p = 0.03 between the groups). On the basis of these preliminary data, we conclude that long-term treatment with ALC may be of potential value in preventing the progressive loss of myocardial sympathetic nervous function in patients with diabetes. MIBG-SPET is a sensitive and thus valuable method in assessing the development of myocardial sympathetic nervous dysfunction.