We examined fasting plasma insulin, acylation-stimulating protein (ASP), leptin, adiponectin, ghrelin, and metabolic/cardiovascular risk profile before and 15 +/- 6 months after isolated Roux-en-Y gastric bypass surgery in 50 morbidly obese subjects. Average preoperative plasma lipids were mostly normal, whereas ASP, insulin, and leptin were elevated, and adiponectin and ghrelin were decreased. Postoperatively, body weight decreased significantly (-36.4 +/- 9.6%) and was best predicted by preoperative adiponectin concentration in weight-stable subjects (r = -0.59; P = 0.02). Plasma lipids and insulin resistance improved, leptin and ASP decreased (-76.3 +/- 14.6% and -35.9 +/- 52.2%; P < 0.001), and adiponectin increased (50.1 +/- 47.0%; P < 0.001). The decrease in apolipoprotein B was best predicted by the decrease in ASP (r = 0.55; P = 0.009), whereas the improved postoperative insulin sensitivity was best predicted by the increase in adiponectin (r = 0.70; P = 0.01). Despite bypassing 95% of the stomach and isolating the fundus from contact with ingested nutrients, circulating ghrelin did not decrease after surgery. In fact, plasma ghrelin increased postoperatively in the subset of subjects undergoing active weight loss (+60.5 +/- 23.2%; P< 0.001); ghrelin, however, remained unchanged in weight-stable subjects. In summary, 1) preoperative adiponectin concentrations may be predictive of the extent of weight loss; 2) changes in ASP and adiponectin are predictive of decreased apolipoprotein B and improved insulin action, respectively; and 3) plasma ghrelin increases after gastric bypass surgery in patients experiencing active weight loss.

The present data suggest involvement of the ASP/adipsin pathway in the pathogenesis of obesity.

The objective of this study was to test the hypothesis that increased fatty acid trapping by subcutaneous adipose tissue might contribute to the development and/or maintenance of obesity. To do so, venoarterial (V-A) gradients across subcutaneous adipose tissue for triglycerides, glycerol, nonesterified fatty acid (NEFA), and acylationstimulating protein (ASP) were determined in eight lean females [body mass index (BMI), 22.2 ؎ 0.6] and eight obese females (BMI, 34.4 ؎ 3.4). Plasma insulin was also measured at intervals throughout this period. Fasting plasma triglyceride was significantly higher in the obese group and postprandial triglyceride was also significantly delayed. In contrast, both triglyceride clearance and fatty acid uptake by subcutaneous adipose tissue were significantly greater in the obese group compared with the lean group. Fasting insulin did not differ between the groups, but postprandial insulin values were significantly higher in the obese group. The pattern of ASP release from subcutaneous adipose tissue also appeared to differ in that it was significantly greater in the early postprandial period (0-90 min) in the obese group versus the lean group and this correlated with greater triglyceride clearance during this period. Moreover, there were strong, positive correlations between BMI and the V-A gradient for fasting ASP, the 0-to 90-min area under the curve (AUC) for ASP V-A gradient fasting insulin, and the 0to 90-min AUC for fatty acid incorporation into adipose tissue. Taken together, these data demonstrate that fatty acid trapping by adipose tissue can be increased even when overall plasma triglyceride clearance is delayed. The postprandial pattern of insulin, in particular, was altered in the obese, although it is certainly possible that differences in ASP release or response could also contribute to increased fatty acid trapping in the obese. The data, therefore, suggest that increased fatty acid trapping by adipose tissue may be a feature of some forms of obesity. -Kalant, D., S. Phélis, B. A. Fielding, K. N. Frayn, K. Cianflone, and A. D. Sniderman. Increased postprandial fatty acid trapping in subcutaneous adipose tissue in obese women.

No abstract