Abstract 439: Niacin Does Not Accelerate Reverse Cholesterol Transport in Man

BackgroundHDL may be atheroprotective by accelerating reverse cholesterol transport (RCT). Niacin raises HDL cholesterol (HDL-c) and niacin monotherapy up to 3g/d prevented coronary events, possibly by accelerating RCT. However, up to 2g/d niacin did not prevent outcomes beyond aggressive LDL lowering including statins, arguing against RCT-mediated atheroprotection. We developed a novel method to assess macrophage-to-lipoprotein RCT in vivo. Preliminary studies in mice demonstrate that albumin-bound tritiated cholesterol (3H-Chol) is rapidly removed ( 95% in 30min) by resident macrophages. We monitored subsequent reappearance over 8d by macrophage-to-lipoprotein RCT as 3H-Chol rate of appearance (RA pre-post therapy, %3H-Chol injected/mol cholesterol/h) and tracer fecal excretion (%3H-Chol injected/g feces), and further analyzed RCT by multi-compartmental modeling. ResultsNiacin raised HDL-c 44% vs 17% on placebo (p=0.02) and dropped non HDL-c 40% (p<0.0001). Niacin and placebo did not differ by HDL 3H-Ch...