Helicobacter pylori infection can affect energy modulating hormones and body weight in germ free mice

Abstract

Helicobacter pylori, is an invariably commensal resident of the gut microbiome associated with gastric ulcer in adults. In addition, these patients also suffered from a low grade inflammation that activates the immune system and thus increased shunting of energy to host defense mechanisms. To assess whether a H. pylori infection could affect growth in early life, we determined the expression levels of selected metabolic gut hormones in germ free (GF) and specific pathogen-free (SPF) mice with and without the presence of H. pylori. Despite H. pylori-infected (SPFH) mice display alteration in host metabolism (elevated levels of leptin, insulin and peptide YY) compared to non-infected SPF mice, their growth curves remained the same. SPFH mice also displayed increased level of eotaxin-1. Interestingly, GF mice infected with H. pylori (GFH) also displayed increased levels of ghrelin and PYY. However, in contrast to SPFH mice, GFH showed reduced weight gain and malnutrition. These preliminary findings show that exposure to H. pylori alters host metabolism early in life; but the commensal microbiota in SPF mice can attenuate the growth retarding effect from H. pylori observed in GF mice. Further investigations of possible additional side effects of H. pylori are highly warranted.

Helicobacter pylori Infection Aggravates Diet-induced Insulin Resistance in Association With Gut Microbiota of Mice

“…3A–C). H. pylori has been reported to influence physiological regulation of metabolic hormones involved in food intake, energy expenditure and body mass (Khosravi et al, 2015). We found that the serum level of gastric inhibitory polypeptide (GIP) and leptin were higher in animals infected with H. pylori when given a normal diet at 12 weeks compared to the non-infected controls, and the level of GIP was further increased in H. pylori -infected group fed HFD compared with HFD controls (Fig.…”

“…Recent reports have highlighted that there is an ongoing crosstalk between H. pylori and the gut microbiota which is associated with the gut inflammation (Khosravi et al, 2015). Thus, we investigated whether the aggravating effect of H. pylori on HFD-induced IR is associated with perturbation of the gut microbiota.…”

“…In addition to inflammation hypothesis, increasing evidence indicates that H. pylori infection can influence the production of metabolic hormones involved in energy homeostasis both in human and animal studies, which is another potential mechanism for H. pylori -associated insulin resistance (Boltin and Niv, 2012, Khosravi et al, 2015, Roper et al, 2008). In our study, we also found remarkable changes of metabolic hormones after H. pylori infection given HFD.…”

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“…However, the increase of GIP in germ free mice was not statistically significant. Thus Hp down-regulated the expression of host GLP-1 or accelerates the degradation of incretins (a class of neuropeptides that represent insulin secretion stimulators) [12]. Both of the peptides are implicated in adequate glucose metabolism by the cells.…”

“…The activation of the immune system also elevated levels of leptin (also known as "hunger hormone"), insulin and peptide YY [12].…”