Objective: To evaluate the impact of moderate body weight loss on both adipose tissue lipoprotein lipase (AT-LPL) activity and expression and to verify whether variation in AT-LPL could be related to changes in lipid-lipoprotein metabolism.
Design: Intervention study of a 15-week weight reducing program (energy deficit: 500-800 kcal/d below the subjects' estimated sedentary energy expenditure).
Subjects: Thirty two obese subjects (14 men and 18 premenopausal women; aged 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 lipoprotein cholesterol (HDL-C, LDL-C), and triglycerides at baseline and 4-6 weeks after the 15-week weight reducing program, when subjects were weight stable.
Results: In response to weight loss, AT-LPL activity of both regions did not change in men, but decreased in women. Regarding AT-LPL expression, no interaction between time and sex was observed in response to the treatment. In both genders, the higher was the basal AT-LPL activity, the greater was the reduction of this enzyme activity in response to weight loss, in both the 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 whereas only plasma TG and LDL-C levels were decreased in women (P<0.05). Although the average reduction in HDL-C levels in response to weight loss was 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) in response to weight loss, in women. An inverse relationship was observed between 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 are related to weight loss induced variation in plasma HDL-C concentrations.