Effects of weight loss, induced by gastric bypass surgery, on HDL remodeling in obese women

Abstract

Plasma lipoproteins and glucose homeostasis were evaluated after marked weight loss before and over 12 months following Roux-en-Y gastric-bypass (RYGBP) surgery in 19 morbidly obese women. Standard lipids, remnant-lipoprotein cholesterol (RLP-C); HDL-triglyceride (TG); apolipoproteins (apo) A-I, A-II, E, and A-I-containing HDL subpopulations; lecithin-cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP) mass and activity; plasma glucose and insulin levels were measured before and at 1, 3, 6, and 12 months after GBP surgery. Baseline concentrations of TG, RLP-C, glucose, and insulin were significantly higher in obese than in normal-weight, age-matched women, whereas HDL cholesterol (HDL-C), apoA-I, apoA-II, alpha-1 and alpha-2 levels were significantly lower. Over 1 year, significant decreases of body mass index, glucose, insulin, TG, RLP-C, HDL-TG, and prebeta-1 levels were observed with significant increases of HDL-C and alpha-1 levels (all P < 0.05). Changes of fat mass were correlated with those of LDL cholesterol (P = 0.018) and LCAT mass (P = 0.011), but not with CETP mass (P = 0.265). Changes of fasting plasma glucose concentrations were inversely correlated with those of CETP mass (P = 0.005) and alpha-1 level (P = 0.004). Changes of fasting plasma insulin concentrations were positively correlated with those of LCAT mass (P = 0.043) and inversely with changes of alpha-1 (P = 0.03) and alpha-2 (P = 0.05) concentrations. These results demonstrate beneficial changes in HDL remodeling following substantial weight loss induced by RYGBP surgery and that these changes are associated with improvement of glucose homeostasis in these patients.

Figures

Fig. 1.

ApoA-I-containing HDL subpopulations of a representative subject before and 12 month after GBP surgery. Baseline values: HDL-C, 41.5 mg/dl; apoA-I, 124 mg/dl; TG, 214 mg/dl; α-1 HDL, 10.4 mg/dl; and α-2 HDL, 28.2 mg/dl. Values at 12 months: HDL-C, 48.1 mg/dl; apoA-I, 129 mg/dl; TG, 128 mg/dl; α-1, 22.7 mg/dl; and α-2 HDL, 34.5 mg/dl. While HDL-C and apoA-I levels increased 16% and 4%, there was a redistribution of apoA-I-containing HDL particles toward large particles with 117% and 22% increases in α-1 and α-2 levels.

Fig. 2.

Best curve fit of mean values of CETP and LCAT masses and activities obtained from plasma samples collected at baseline and at 1, 3, 6, and 12 months following gastric bypass surgery.