Objective: To determine effects of single ascending doses of MDCO-216 on high-density lipoprotein (HDL) subfractions in relation to changes in cholesterol efflux capacity in healthy volunteers and in patients with stable angina pectoris.
Approach and results: Doses of 5- (in volunteers only), 10-, 20-, 30-, and 40-mg/kg MDCO-216 were infused during 2 hours, and plasma and serum were collected during 30 days. Plasma levels of HDL subfractions were assessed by 2-dimensional gel electrophoresis, immunoblotting, and image analysis. Lipoprotein particle concentrations and sizes were also assessed by proton nuclear magnetic resonance ((1)H-NMR). There was a rapid dose-dependent increase of total apolipoprotein A-I (apoA-I) in pre-β1, α-1, and α-2 HDL levels and decrease in α-3 and α-4 HDL. Using a selective antibody apoA-IMilano was detected in the large α-1 and α-2 HDL on all doses and at each time point. ApoA-IMilano was also detected at the α-4 position but only at high doses. (1)H-NMR analysis similarly showed a rapid and dose-dependent shift from small- to large-sized HDL particles. The increase of basal and ATP-binding cassette transporter A1-mediated efflux capacities reported previously correlated strongly and independently with the increase in pre-β1-HDL and α-1 HDL, but not with that in α-2 HDL.
Conclusions: On infusion, MDCO-216 rapidly eliminates small HDL and leads to formation of α-1 and α-2 HDL containing both wild-type apoA-I and apoA-IMilano. In this process, endogenous apoA-I is liberated appearing as pre-β1-HDL. In addition to pre-β1-HDL, the newly formed α-1 HDL particle containing apoA-I Milano may have a direct effect on cholesterol efflux capacity.
Keywords: apolipoprotein A-I; cholesterol; healthy volunteers; immunoblotting; stable angina.
© 2016 American Heart Association, Inc.