Differential Effects of Bariatric Surgery on Plasma Levels of ANGPTL3 and ANGPTL4.

Introduction: Angiopoietin-like protein 3 (ANGPTL3) and 4 (ANGPTL4) are regulators of triglycerides storage and utilization. Bariatric surgery (BS) determines profound changes in adipose tissue composition and energy metabolism. We evaluated the impact of BS on plasma levels of ANGPTL3 and ANGPTL4.Method: Twenty-seven morbidly obese subjects with or without type 2 diabetes (T2D) underwent Roux-en-Y gastric bypass (RYGB) and 18 patients with advanced T2D received Biliopancreatic Diversion (BPD). Fasting ANGPTLs levels, insulin sensitivity (evaluated by euglycemic hyperinsulinemic clamp), total bile acids (TBA) and free fatty acids (FFA) were measured at baseline and 1year after surgery.Results: Both surgical procedures resulted in fat mass loss, improved glucose control, and a ~2-fold increase of insulin sensitivity. ANGPTL4 levels decreased significantly with both RYGB (26.6 ± 0.6 to 24.4 ± 0.3 ng/mL, p=0.001) and BPD (27.9 ± 1.5 to 24.0 ± 0.5 ng/mL, p=0.003). In contrast, ANGPTL3 concentrations did not change after RYGB but rose following BPD (225 ± 20 to 300 ± 15 ng/mL, p=0.003). By multiple regression analysis, changes in ANGPTL4 were independently associated with those of blood glucose, p=0.0169) whereas changes in ANGPTL3 after BPD were associated with variations in FFA (p=0.008) and insulin sensitivity (p=0.0427). Discussion: Circulating ANGPTL4 is reduced by BS probably due to the loss of fat mass and improved insulin sensitivity. Conversely, ANGPTL3 levels increased after BPD, presumably because of the metabolic changes induced by the malabsorptive effect of this surgical procedure.