Endocrine Abstracts

Background and aims: In adipose tissue, excess of energy is stored inside cytosolic lipid droplets as triglycerides. During fasting or exercise, the stored fat is mobilized for utilization as free fatty acids and glycerol via lipolysis. The complete lipolysis of triglycerides is mediated by the orchestrated activation of adipose triglyceride lipase (ATGL) and hormone-sensitive lipase, which have been associated with obesity. There is compelling evidence that the protein comparative gene identification 58 (CGI-58) markedly enhances ATGL-mediated lipolysis. However, to date, only few studies have evaluated the association between CGI-58 and obesity, with inconclusive results. Thus, here, we compared CGI-58 expression in subcutaneous adipose tissue (SAT) of subjects with different body mass index (BMI) categories. We also evaluated if CGI-58 correlates with body composition parameters, resting energy expenditure (REE), insulin resistance (IR), and lipid and glycemic profiles.

Methods: SAT biopsies were obtained from 59 individuals who underwent bariatric surgery or elective abdominal surgery. Patients were divided in Group 1 (n=8; BMI<25.0 kg/m²), Group 2 (n=22; BMI 30.0 – 39.9 kg/m²) and Group 3 (n=29; BMI ≥ 40.0 kg/m²). CGI-58 expression in SAT was quantified using real-time PCR (qPCR).

Results: CGI-58 expression was decreased in Group 3 [median 0.60 (0.56 – 0.82, 25^th–75^th percentiles)] and Group 2 [0.89 (0.70 – 1.10)] compared to Group 1 patients [2.48 (1.64 – 3.23)] (P<0.00001). Accordingly, CGI-58 expression was negatively correlated with BMI values (r=−0.424, P<0.001). Moreover, after BMI adjustment, CGI-58 expression was negatively correlated with waist circumference (r=−0.525, P<0.001), fat-free mass (r=−0.290, P=0.030), insulin (r=−0.266, P=0.047), HbA1c (r=−0.379, P=0.003), and triglycerides (r=−0.521, P<0.001), while it was positively correlated with adiponectin levels (r=−0.277, P=0.044).

Conclusion: CGI-58 expression is decreased in patients with obesity, being associated with worse metabolic profile.