Effect of propionyl-L-carnitine on exercise performance in peripheral arterial disease

Background: Supplementation with propionyl-L-carnitine (PLC) may be of use in improving the exercise capacity of people with peripheral arterial disea se. Methods: After a 2-wk exercise familiarization phase, seven subjects di splaying intermittent claudication were studied over a 12-wk period consist ing of three 4-wk phases, baseline (B), supplementation (S), and placebo (P ). PLC was supplemented at 2 g(.)d(-1), and subjects were blinded to the or der of supplementation. Unilateral calf strength and endurance were assesse d weekly. Walking performance was assessed at the end of each phase using a n incremental protocol, during which respiratory gases were collected. Resu lts: Although there was not a significant increase in maximal walking time (similar to 14%) in the whole group, walking time improved to a greater ext ent than the individual baseline coefficient of variation in four of the se ven subjects. The changes in walking performance were correlated with chang es in the respiratory exchange ratio both at steady state (r = 0.59) and ma ximal exercise (r = 0.79). Muscle strength increased significantly from 695 +/- 198 N to 812 +/- 249 N by the end of S. Changes in calf strength from B to S were modestly related to changes in walking performance (r = 0.56). No improvements in calf endurance were detected throughout the study. Concl usions: These preliminary data suggest that, in addition to walking perform ance, muscle strength can be increased in PAD patients after 4 wk of supple mentation with propionyl-L-carnitine.