Persistence of abnormalities in metabolism of apolipoproteins B-100 and A-I after weight reduction in patients with primary hypertriglyceridemia

Obesity commonly accompanies hypertriglyceridemia, and weight reduction is widely recommended for treatment of elevated triglyceride levels. To determine whether weight reduction will normalize lipoprotein metabolism in overweight, hypertriglyceridemic patients, 10 such male patients underwent weight loss until their body weights were within the desirable range. After reestablishment of a steady state in body weight at the lower level, measurements were made of plasma lipid, lipoprotein, and apolipoprotein levels and the kinetics of low density lipoprotein (LDL) apolipoprotein B-100 (apo B) and apolipoprotein A-I (apo A-I). The patients lost an average of 10.6±2.1 kg (mean±SEM). Plasma triglyceride concentrations fell from 431±42 mg/dl to 248±27 mg/dl (p<0.001), whereas concentrations of total cholesterol, LDL cholesterol, total apo B, and high density lipoprotein (HDL) cholesterol were unchanged after weight loss. On average, the fractional catabolic rates (FCRs) for LDL were much higher in the patients after weight loss than in 16 normal control subjects (0.55±0.06 versus 0.31±0.06 pool/day), and input rates for LDL also were higher for hypertriglyceridemic patients after weight loss (22.2±2.4 versus 12.8±23 mg/ kg ·day). Compared with 20 normal control subjects, hypertriglyceridemic patients after weight reduction had persistent low HDL cholesterol levels (32±2 versus 54±3 mg/dl) as well as low apo A-I levels (99±5 versus 122±4 mg/dl). In addition, the patients had higher FCRs for apo A-I than did control subjects (0.271±0.016 versus 0.198±0.012 pool/day), but input rates were not significantly different (11.24±0.64 versus 10.50±0.50 mg/kg ·day). Thus, despite weight reduction, several abnormalities in lipoprotein levels and apolipoprotein kinetics persisted. (Arteriosclerosis and Thrombosis 1992;12:976-984).