Evaluation of GH/IGF-I Axis and of Replacement GH Therapy After Bariatric Surgery in Patients With Very Severe Obesity: Relationships With Body Composition

Detailed Summary

Obesity and obesity-related diseases have reached epidemic proportions in Western countries (1-3). Laparoscopic-adjustable silicone gastric banding (LASGB) is a purely restrictive operation that determine effective weight loss without inducing malabsorption (4-6). However, also after LASGB body weight loss is almost invariably associated with Free Fat Mass (FFM) loss, and the relevance of the FFM contribution to total energy expenditure is well-known (7-8). Different endocrine axes are reported to affect FFM. We previously reported that low levels of DHEA-S, an adrenal steroid with controversial anti-adipogenic and anti-atherogenic effects, are increased after the massive and sustainable weight loss induced by LASGB in severely obese premenopausal women and correlated with the higher post-operative FFM (9-10). It is also well known that GH/IGF-I axis exerts relevant effects on FFM and that reduced GH levels might increase Fat Mass (FM) and reduce FFM (11,12). Morbidly obese patients have a reduced GH secretion, generally reversible after weight loss (13-14). In a recent study currently in press, we reported that a persistent deficiency in the GH/IGF-I axis in very obese females is associated to lower decrease in FM after LASGB. Low IGF-I plasma levels have also been reported to be independent prognostic factors of liver steatosis and non-alcoholic steatohepatitis in morbidly obese patients (15) and ultrasound- measured hepatic left lobe volume might represent a reliable tool for the evaluation of liver involvement in obesity (16). GH deficiency (GHD) in adult patients is associated with an increase in FM and a parallel decrease in FFM (17). The severity of GDH is correlated to cardiovascular risk, body composition abnormalities and bone loss, and decreased left ventricular ejection fraction (18-20). GH therapy has been demonstrated to be effective in normalizing body composition, with beneficial effects up to a 2-years follow-up period (21-24). GH therapy has also been reported to be effective in sparing FFM during weight loss in obese patients and metabolic syndrome (25,26). However, these studies have some limitations due to the duration of the treatment and the lack of a preliminary evaluation of the GH/IGF-I axis secretory status in obese patients before the GH therapy. At present there are no data on the evaluation of the GH/IGF-I status before and after bariatric surgery and the effectiveness of recombinant GH treatment in very severe obese patients.

Study Details

Timeline

Interventions