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

Abstract

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 de®cit: 500 ± 800 kcalad 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 ( 7 0.53`r`7 0.84, P values ranging from 0.0001 to 0.05). Body weight loss promoted a signi®cant 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 signi®cant, 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 7 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.

Hormone sensitive lipase expression and adipose tissue metabolism show gender difference in obese subjects after weight loss

“…10 -12 Some studies have shown increase in LPL activity and mRNA expression in obese subjects during weight loss 10,11 and another, increase in activity, but no change in LPL mRNA expression in women, and no change in either of these parameters in men. 12 Furthermore, women have been shown to have higher LPL mRNA expression and activity in abdominal subcutaneous adipose tissue than men. 26 Underlining further the complexity of adipose tissue metabolism in obesity, contrasting findings have also been reported in respect of changes found in basal and maximal lipolysis in response to weight reduction in women.…”

“…To the best of our knowledge, gender differences have not been reported before between obese men and women in HSL expression along weight reduction, although many other aspects of adipose tissue metabolism have been studied and compared. 12,26,32,46 Previously, it has been found that HSL expression is a major determinant of maximal lipolytic capacity of the human fat cell and that is markedly affected by the cell size. 47 -49 Furthermore, fat cell size has a great influence on the rate of lipolysis, 50 larger cells being lipolytically more active.…”

“…In addition, there are only a few studies that have shown gender difference in LPL activity and expression 25,26 in obesity or have compared LPL expression between genders along with weight reduction. 12 Gender differences have been observed in lipolytic responses as well as in fatty acid uptake of adipose tissue, 27 -31 although the difference in metabolic changes between genders due to weight reduction does not seem to be so evident. 32,33 All these data suggest that the relative contribution of LPL and HSL to the development of the fat mass and its reduction during weight loss is still controversial and largely unclear.…”

“…8,9 In addition, conflicting data exist when LPL activity has been measured after weight reduction. Some studies have shown an increase, 10,11 some no change or even a decrease 12 in LPL expression and activity after weight loss. Regarding HSL, its activity and expression have also been found altered in obesity.…”

Effect of normal-fat diets, either medium or high in protein, on body weight in overweight subjects: a randomised 1-year trial

“…The amount of adipose tissue High-protein diet, weight loss, weight maintenance A Due et al located in the intra-abdominal region is more tightly correlated with metabolic complications in obese patients than is subcutaneous fat. [16][17][18] The distribution of fat mass in the intra-abdominal depot may be influenced by gender 19 and cortisol. The mechanism by which the HP diet reduced the intra-abdominal fat is not known, but it is interesting that the effect was maintained after adjustment for weight loss, which suggests that the finding cannot be explained by the slightly greater weight loss in the HP group.…”