Density of ghrelin-producing cells is higher in the gastric mucosa of morbidly obese patients

Abstract

Ghrelin is a peptide mainly secreted by gastric mucosa and has been implicated in the regulation of eating behavior and weight balance. Obesity and Helicobacter pylori infection are associated with changes in plasma ghrelin levels. This study was designed to evaluate the density of ghrelin-producing cells in the gastric mucosa of morbidly obese and dyspeptic non-obese patients, with and without H. pylori infection. Gastric biopsies of the antral and oxyntic mucosa were obtained from 50 morbidly obese patients (BMI >40, 21 with metabolic syndrome (MS)), 17 dyspeptic overweight subjects (25<BMI<30), and 33 lean individuals (BMI<25) and processed for histology and immunohistochemistry. Ghrelin-immunoreactive cell densities in the oxyntic mucosa were similar in morbidly obese patients with MS and in overweight and lean patients, whereas morbidly obese patients without MS presented higher ghrelin-immunoreactive cell density. The number of ghrelin cells in the oxyntic mucosa was significantly lower in obese and non-obese H. pylori-infected subjects. Ghrelin-immunoreactive cells, although sparse in the antral mucosa, were found more frequently in obese patients and their numbers did not seem to be affected by H. pylori infection. The higher expression of ghrelin-immunoreactive cells in the oxyntic mucosa of morbidly obese patients compared with non-obese subjects or with morbidly obese subjects with MS and the finding of a higher number of small foci of ghrelin cells in the antral mucosa of obese patients may indicate an adaptive mechanism or an individual factor to be considered in the pathogenesis of obesity.