Effect of a moderate weight loss on adipose tissue lipoprotein lipase activity and expression: existence of sexual variation and regional differences

OBJECTIVE: To evaluate the impact of moderate body weight loss on both adip ose tissue lipoprotein lipase (AT-LPL) activity and expression and to verif y whether variation in AT-LPL could be related to changes in lipid-lipoprot ein metabolism. DESIGN: Intervention study of a 15-week weight reducing program (energy def icit: 500-800 kcal/d below the subjects' estimated sedentary energy expendi ture), SUBJECTS: Thirty two obese subjects (14 men and 18 premenopausal women; age d 36-50 y) whose body fatness ranged from 34 to 54% fat. MEASUREMENTS: Adipose tissue biopsies from the abdominal and femoral depots , various fatness and fat distribution parameters (computed tomography and anthropometry), fasting plasma concentrations of high- and low-density lipo protein cholesterol (HDL-C, LDL-C), and triglycerides at baseline and 4-6 w eeks after the 15-week weight reducing program, when subjects were weight s table. RESULTS: In response to weight loss, AT-LPL activity of both regions did no t change in men, but decreased in women. Regarding AT-LPL expression, no in teraction between time and sex was observed in response to the treatment, I n both genders, the higher was the basal AT-LPL activity, the greater was t he reduction of this enzyme activity in response to weight loss, in both th e abdominal and femoral depots (-0.53 < r < -0.84, P values ranging from 0. 0001 to 0.05). Body weight loss promoted a significant reduction in plasma triglyceride (TG), insulin and LDL-cholesterol (C) concentrations in men wh ereas only plasma TG and LDL-C levels were decreased in women (P < 0.05). A lthough the average reduction in HDL-C levels in response to weight loss wa s not significant, the higher was the decrease in femoral AT-LPL activity, the greater was the reduction in plasma HDL-C levels (r = 0.50, P < 0.05) i n response to weight loss, in women. An inverse relationship was observed b etween changes in femoral AT-LPL activity and HDL-C levels variation in men (r = -0.64, P < 0.05). CONCLUSION: (1) variation in AT-LPL activity differs between men and women in response to moderate body weight loss although the corresponding enzyme mRNA levels remain unchanged; and (2) changes in femoral AT-LPL activity ar e related to weight loss induced variation in plasma HDL-C concentrations.