Editorial
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World J Gastroenterol. Mar 14, 2011; 17(10): 1249-1260
Published online Mar 14, 2011. doi: 10.3748/wjg.v17.i10.1249
Endocrine impact of Helicobacter pylori: Focus on ghrelin and ghrelin o-acyltransferase
Penny L Jeffery, Michael A McGuckin, Sara K Linden
Penny L Jeffery, Michael A McGuckin, Mucosal Diseases Program, Mater Medical Research Institute, Mater Health Services, South Brisbane, Queensland, 4101, Australia
Sara K Linden, Mucosal Immunobiology and Vaccine Center, Sahlgrenska Academy, University of Gothenburg, Box 435, 405 30 Gothenburg, Sweden
Author contributions: All authors contributed to this work.
Supported by The Swedish Research Council (Vetenskapsrådet: K2008-58X-20693-01-4), Novo Nordisk Foundation (SL), National Health and Medical Research Council of Australia (Project No. 488811), and a Queensland Government Smart Futures Fellowship (PLJ)
Correspondence to: Sara K Linden, PhD, Assistant Professor, Mucosal Immunobiology and Vaccine Center, Sahlgrenska Academy, University of Gothenburg, Box 435, 405 30 Gothenburg, Sweden. sara.linden@gu.se
Telephone: +46-31-7863058   Fax: +46-31-7866330
Received: September 20, 2010
Revised: December 21, 2010
Accepted: December 28, 2010
Published online: March 14, 2011
Abstract

Ghrelin is predominantly produced by the gastric enteroendocrine cell compartment and is octanoylated by the recently discovered ghrelin o-acyltransferase (GOAT) before secretion into the bloodstream. This octanoylation is essential for many of the biological properties of ghrelin including appetite stimulation and anti-inflammatory properties as only the acylated form of ghrelin binds to the ghrelin receptor, the growth hormone secretagogue receptor (GHS-R). Given the gastric location of ghrelin production, it is perhaps not surprising that insult to the gastric mucosa affects circulating ghrelin levels in humans. Helicobacter pylori (H. pylori) infects more than fifty percent of the world’s population and once established within the gastric mucosa, can persist for life. Infection is associated with chronic gastritis, gastric atrophy and ulceration, reduced appetite and a lower body mass index (BMI). The large majority of studies investigating levels of circulating ghrelin and ghrelin expression in the stomach in patients with H. pylori infection indicate that the bacterium has a negative impact on ghrelin production and/or secretion. Eradication of infection restores ghrelin, improves appetite and increases BMI in some studies, however, a causative relationship between H. pylori-associated serum ghrelin decline and food intake and obesity has not been established. Most studies measure total ghrelin in the circulation although the measurement of the ratio of acyl/total ghrelin gives a clearer indication that the ghrelin acylation process is altered during infection and atrophy. GOAT is essential for the production of biologically-active, acyl ghrelin and the impact of H. pylori on GOAT expression and activity will be highly informative in the future.

Keywords: Appetite; Ghrelin; Ghrelin o-acyltransferase; Helicobacter pylori; Infection; Inflammation; Obesity