Attenuated aerobic exercise capacity in CD36 deficiency

Background: An important role of CD36 in muscle fatty-acid (FA) uptake has been demonstrated in CD36-knockout or CD36-overexpressed mice. FA is a predominant substrate in energy production during light exercise below the anaerobic threshold (AT). We studied whether aerobic exercise capacity in humans could be affected by CD36 deficiency. Participants and methods: We investigated the ventilatory threshold (VT) as well as serum FA changes in normal (n = 22) and CD36 deficient subjects (n = 12) during pedaling on a cycle ergometer. Results: In CD36 deficient individuals FA levels were not decreased at peak work rate while FA levels were decreased by about 50% in normal subjects. CD36 deficient subjects showed significantly lower VT than normal subjects. A significant correlation was observed between VT and % changes in FA at peak work rate. Conclusion: Present study demonstrated a reduced FA utilization and an attenuated aerobic exercise capacity in CD36 deficiency, indicating that CD36-mediated FA oxidation is an important determinant for human aerobic exercise capacity.