Endocrine Abstracts

Context: Adipose tissue distribution is closely related to metabolic disease risk. GH reduces visceral and total body adipose tissue mass, while inducing whole body insulin resistance.

Objective: To assess the role of visceral adipose tissue and derived adipokines for the systemic insulin resistance and lipid metabolism, before and after treatment in acromegaly.

Patients: Sixty-six adult patients with active acromegaly diagnosed between 2005–2013 at a tertiary referral center were evaluated before (n=66, 24 female, 42 male, age 48.8±13.9), and after (n=28) different treatments (somatostatin analogues or/and transphenoidal surgery).

Outcome Measures: HOMA-IR was derived from fasting glucose and insulin. Body composition and visceral adipose tissue (Dual-energy X-ray Absorptiometry, Lunar Prodigy), lipid profile (total-, HDL-, LDL- cholesterol, Lp(a), ApoA, and ApoB), hsCRP, and selected adipokines (adiponectin, leptin, vaspin and omentin) were measured. The determinants for the baseline HOMA-IR and the change after treatment were explored in a stepwise multivariate linear regression model.

Results: At baseline, HOMA-IR was best predicted by total trunk fat mass and IGF1 (r²=0.44, P=0.002). GH was negatively correlated with all the adipose tissue depots (arms r=0.60, legs r=0.42, trunk r=0.75, visceral r=0.49, and total r=0.66, P<0.001 for all) and positively with serum vaspin (r=0.25, P=0.046). After treatment, all the adipose tissue depots increased significantly, whereas HOMA-IR decreased. Vaspin decreased (0.32 (0.53) vs 0.18 (0.30) ng/ml, P<0.001), omentin increased (430±129 vs 499±149 ng/ml, P=0.001), while no significant change was observed for adiponectin and leptin. Although lipid profile improved, hsCRP increased (0.25 (0.3) vs 0.7 (1.9) mg/l, P<0.001).

Conclusions: Glucose and lipid metabolism parameters improved after treatment despite an increase of visceral and total adipose tissue. In contrast to other metabolic disorders, visceral adipose tissue mass was a weaker determinant of the baseline and the change of HOMA-IR compared to the total trunk fat mass. Vaspin may have a possible pathogenic role in insulin resistance of acromegaly.