Altered GH-IGF-1 Axis in Severe Obese Subjects is Reversed after Bariatric Surgery-Induced Weight Loss and Related with Low-Grade Chronic Inflammation.

Paula Juiz-Valiña,Enrique Mena,Maria Cordido,Elena Outeiriño-Blanco,Lara Pena-Bello,Fernando Cordido,Barbara Varela-Rodriguez,Maria Jesus Garcia-Brao,Sonia Pértega,Susana Sangiao-Alvarellos

doi:10.3390/jcm9082614

Abstract

Endocrine disorders are common in obesity, including altered somatotropic axis. Obesity is characterized by reduced growth hormone (GH) secretion, although the insulin-like growth factor-1 (IGF-1) values are controversial. The aim of this study was to evaluate the effect of weight loss after bariatric surgery in the GH–IGF-1 axis in extreme obesity, in order to investigate IGF-1 values and the mechanism responsible for the alteration of the GH–IGF-1 axis in obesity. We performed an interventional trial in morbidly obese patients who underwent bariatric surgery. We included 116 patients (97 women) and 41 controls (30 women). The primary endpoint was circulating GH and IGF-1 values. Circulating IGF-1 values were lower in the obese patients than in the controls. Circulating GH and IGF-1 values increased significantly over time after surgery. Post-surgery changes in IGF-1 and GH values were significantly negatively correlated with changes in C-reactive protein (CRP) and free T4 values. After adjusting for preoperative body mass index (BMI), free T4 and CRP in a multivariate model, only CRP was independently associated with IGF-1 values in the follow-up. In summary, severe obesity is characterized by a functional hyposomatotropism at central and peripheral level that is progressively reversible with weight loss, and low-grade chronic inflammation could be the principal mediator.

Highlights

The main result of the present study is that insulin-like growth factor-1 (IGF-1) values are decreased in patients with morbid obesity, and that weight loss after bariatric surgery drives a progressive increase in growth hormone (GH) and IGF-1
The present results suggest that the reduced GH found in obese subjects is not due to a feedback inhibition by elevated IGF-1, since extreme obesity is associated with a decline in IGF-1 values
This study shows that in patients with morbid obesity, weight loss induced with bariatric surgery brings about a restoration of the altered GH–IGF-1 axis decline

Summary

Introduction

The prevalence of obesity has experienced a continuous increase in most countries since 1980. The disease burden related to high body mass index (BMI) has progressively increased since 1990 mainly due to cardiovascular disease [1]. The prevalence of obesity in Spain in 2010 was 22.9% (24.4% among men and 21.4% among women) [2]. It is estimated that the prevalence of obesity and severe obesity will continue to increase [3]. A weight loss of 5% improves metabolic function in numerous organs concurrently, and progressive weight loss causes dose-dependent alterations in key adipose tissue biological pathways [4,5]. Bariatric surgery compared with non-surgical obesity management, has been shown to produce more marked improvements in comorbidities associated with obesity and a higher decrease in all-cause mortality [6]

Objectives

Methods

Results

Discussion

Conclusion