Helicobacter pylori and gut microbiota modulate energy homeostasis prior to inducing histopathological changes in mice

Helicobacter pylori Eradication Therapy Affect the Gut Microbiota and Ghrelin Levels

Background: Antibiotic therapy used to eradicate Helicobacter pylori has been associated with changes in plasma ghrelin and alterations in the gut microbiota. On the other hand, changes in ghrelin levels have been related to changes in gut microbiota composition. Our aim was to evaluate the relationship between changes in the gut microbiota and ghrelin levels in H. pylori infected patients who received antibiotic treatment for its eradication.

Methods: A prospective case-control study that included forty H. pylori-positive patients who received eradication therapy (omeprazole, clarithromycin, and amoxicillin) and twenty healthy H. pylori antigen-negative participants. Patients were evaluated, including clinical, anthropometric and dietary variables, before and 2 months after treatment. Gut microbiota composition was analyzed through 16S rRNA amplicon sequencing (IlluminaMiSeq).

Results: Changes in gut microbiota profiles and decrease in ghrelin levels were identified after H. pylori eradication treatment. Gut bacteria such as Bifidobacterium longum, Bacteroides, Prevotella, Parabacteroides distasonis, and RS045 have been linked to ghrelin levels fasting and/or post meals. Changes in the abundance of Lachnospiraceae, its genus Blautia, as well as Prevotella stercorea, and Megasphaera have been inversely associated with changes in ghrelin after eradication treatment.

Conclusions: Eradication treatment for H. pylori produces changes in the composition of the intestinal microbiota and ghrelin levels. The imbalance between lactate producers such as Blautia, and lactate consumers such as Megasphaera, Lachnospiraceae, or Prevotella, could trigger changes related to ghrelin levels under the alteration of the eradication therapy used for H. pylori. In addition, acetate producing bacteria such as B. longum, Bacteroides, and P. distasonis could also play an important role in ghrelin regulation.

Hallmarks of cancer-the new testament

Diagnosis and treatment of disease demand a sound understanding of the underlying mechanisms, determining any Achilles' heel that can be targeted in effective therapies. Throughout history, this endeavour to decipher the origin and mechanism of transformation of a normal cell into cancer has led to various theories-from cancer as a curse to an understanding at the level of single-cell heterogeneity, meaning even among a single sub-type of cancer there are myriad molecular challenges to overcome. With increasing insight into cancer genetics and biology, the disease has become ever more complex to understand. The complexity of cancer as a disease was distilled into key traits by Hanahan and Weinberg in their seminal 'Hallmarks of Cancer' reviews. This lucid conceptualization of complex cancer biology is widely accepted and has helped advance cancer therapeutics by targeting the various hallmarks but, with the advancement in technologies, there is greater granularity in how we view cancer as a disease, and the additional understanding over the past decade requires us to revisit the hallmarks of cancer. Based on extensive study of the cancer research literature, we propose four novel hallmarks of cancer, namely, the ability of cells to regress from a specific specialized functional state, epigenetic changes that can affect gene expression, the role of microorganisms and neuronal signalling, to be included in the hallmark conceptualization along with evidence of various means to exploit them therapeutically.

The impact of Helicobacter pylori infection on gut microbiota-endocrine system axis; modulation of metabolic hormone levels and energy homeostasis

The gut microbiota is a complex ecosystem that is involved in the development and preservation of the immune system, energy homeostasis and nutritional status of the host. The crosstalk between gut microbiota and the host cells modulates host physiology and metabolism through different mechanisms. Helicobacter pylori (H. pylori) is known to reside in the gastric mucosa, induce inflammation, and alter both gastric and intestinal microbiota resulting in a broad spectrum of diseases, in particular metabolic syndrome-related disorders. Infection with H. pylori have been shown to affect production level and physiological regulation of the gut metabolic hormones such as ghrelin and leptin which are involved in food intake, energy expenditure and body mass. In this study, we reviewed and discussed data from the literature and follow-up investigations that links H. pylori infection to alterations of the gut microbiota and metabolic hormone levels, which can exert broad influences on host metabolism, energy homeostasis, behavior, appetite, growth, reproduction and immunity. Also, we discussed the strong potential of fecal microbiota transplantation (FMT) as an innovative and promising investigational treatment option for homeostasis of metabolic hormone levels to overcome H. pylori-associated metabolic syndrome-related disorders.

Serum level of sex steroid hormone is associated with diversity and profiles of human gut microbiome

Gut microbiota plays roles in host physiology including endocrine function. Although some data suggest a potential connection between biological sex differences and gut microbiota, the connection between sex steroid hormones and gut microbes remained unexplored. The current study investigates the relationship between gut microbes and serum levels of testosterone in men and estradiol in women. Fecal microbiota from a total of 57 men (n = 31) and women (n = 26) were assessed using 16s rRNA gene sequencing. Based on the levels of serum testosterone and estradiol in men and women, respectively, participants were stratified into three groups of Low, Medium, and High. Microbiome communities were analyzed as a function of the steroid hormone within sex. Men and women in the High group harbored more diverse gut microbial communities than others. In men, the abundance of Acinetobacter, Dorea, Ruminococcus, and Megamonas correlated significantly with testosterone levels. Women in the High group have more Bacteroidetes and less Firmicutes phyla than those in the Low group. Genera Slackia and Butyricimonas were significantly correlated with estradiol levels. These results demonstrate that sex steroid hormone levels are correlated with diversity and gut microbial composition, and provide fundamental information helpful for developing communication networks between human and microbial communities.

Antibiotic treatment triggers gut dysbiosis and modulates metabolism in a chicken model of gastro-intestinal infection

Background

Infection of the digestive track by gastro-intestinal pathogens results in the development of symptoms ranging from mild diarrhea to more severe clinical signs such as dysentery, severe dehydration and potentially death. Although, antibiotics are efficient to tackle infections, they also trigger dysbiosis that has been suggested to result in variation in weight gain in animal production systems.

Results

Here is the first study demonstrating the metabolic impact of infection by a gastro-intestinal pathogen (Brachyspira pilosicoli) and its resolution by antibiotic treatment (tiamulin) on the host (chicken) systemic metabolism and gut microbiota composition using high-resolution ¹H nuclear magnetic resonance (NMR) spectroscopy and 16S rDNA next generation sequencing (NGS). Clear systemic metabolic markers of infections such as glycerol and betaine were identified. Weight loss in untreated animals was in part explained by the observation of a modification of systemic host energy metabolism characterized by the utilization of glycerol as a glucose precursor. However, antibiotic treatment triggered an increased VLDL/HDL ratio in plasma that may contribute to reducing weight loss observed in treated birds. All metabolic responses co-occurred with significant shift of the microbiota upon infection or antibiotic treatment.

Conclusion

This study indicates that infection and antibiotic treatment trigger dysbiosis that may impact host systemic energy metabolism and cause phenotypic and health modifications.

Electronic supplementary material

The online version of this article (10.1186/s12917-018-1761-0) contains supplementary material, which is available to authorized users.

Considering gut microbiota disturbance in the management of Helicobacter pylori infection

Helicobacter pylori (Hp) infection produces drastic changes in the gastric microenvironment, which, in turn, influence the gastric microbiota composition and might be correlated with large intestinal microbiota changes. This excellent perturbing actor could trigger important modifications in the homeostatic functions exerted by gut commensals leading to a new gastrointestinal balance. At the same time, the therapeutic strategies used to eradicate Hp can modulate this physiological symbiosis, but can be also conversely affected by its properties. Area covered: The purpose of this review is to explore the reciprocal interplay between Hp infection and gut microbiota and analyze how microbial changes can influence the management of Hp eradication therapies. Expert commentary: While many studies have described Hp-dependent gut microbiota alterations, their clinical implications are only partially clear, as well as the mechanism of actions that sustain these processes. This represents a clear challenge for future research projects that will also need to understand which role is exerted by viruses, parasites, and yeasts.

Possible association of ghrelin/obestatin balance with cardiometabolic risk in obese subjects with Helicobacter pylori

OBJECTIVES

Helicobacter pylori (H. pylori) is a common gastric infection associated with extragastric conditions. The association between H. pylori infection and obesity is unclear. H. pylori may affect gut hormones involved in food intake and energy expenditure. The aim of this study is to evaluate ghrelin/obestatin balance and leptin in obese subjects with H. pylori infection.

METHODS

Sixty healthy volunteers were divided into: obese and non-obese groups. Each group was divided into H. Pylori positive or H. pylori negative. Anthropometric parameters, H. pylori status, serum glucose, insulin level, and lipid profile were estimated with calculation of Homeostasis Model Assessment Insulin Resistance (HOMA-IR). Serum levels of ghrelin, obestatin, and leptin were evaluated.

RESULTS

Significant increase was found in serum glucose, insulin and HOMA-IR ratio in obese subjects with positive H. pylori as compared to other groups. H. pylori positive obese subjects showed significantly increased ghrelin, ghrelin/obestatin balance, and leptin with a significant decrease in obestatin as compared to negative subjects. Ghrelin/obestatin ratio positively correlated with weight, body mass index, waist, glucose, insulin, HOMA-IR, leptin, cholesterol, triglycerides, low density cholesterol and also with H. pylori antigen in the same group.

CONCLUSIONS

It can be concluded that ghrelin, obestatin, and leptin are affected by presence of H. pylori seropositivity in obese subjects. The higher ghrelin levels and ghrelin/obestatin ratio with lowered obestatin could be considered as a gastro-protective effect against inflammation induced by H. pylori.

Heritable components of the human fecal microbiome are associated with visceral fat

Obesity and its associated diseases are one of the major causes of death worldwide. The gut microbiota has been identified to have essential regulatory effects on human metabolism and obesity in particular. In a recent study we provided some insights into the link between the gut microbiota (GM) and adiposity, as well as host genetic modulation of these processes. Our results identify novel evidence of association between 6 adiposity phenotypes and faecal microbial operational taxonomic units (OTUs). Accumulation of visceral fat, a key risk factor for cardio-metabolic disease, has the strongest and most pervasive signature on the gut microbiota of the factors we examined. Furthermore, we observe that the adiposity-associated OTUs were classified as heritable and in some cases were also associated with host genetic variation at obesity-associated human candidate genes FHIT, TDRG1 and ELAVL4. This addendum confirms our previously published results in the TwinsUK cohort using a different approach to OTU clustering and multivariate analysis, and discusses further the importance of considering the GM as a complex ecosystem.

Enteroendocrine cells-sensory sentinels of the intestinal environment and orchestrators of mucosal immunity

The intestinal epithelium must balance efficient absorption of nutrients with partitioning commensals and pathogens from the bodies' largest immune system. If this crucial barrier fails, inappropriate immune responses can result in inflammatory bowel disease or chronic infection. Enteroendocrine cells represent 1% of this epithelium and have classically been studied for their detection of nutrients and release of peptide hormones to mediate digestion. Intriguingly, enteroendocrine cells are the key sensors of microbial metabolites, can release cytokines in response to pathogen associated molecules and peptide hormone receptors are expressed on numerous intestinal immune cells; thus enteroendocrine cells are uniquely equipped to be crucial and novel orchestrators of intestinal inflammation. In this review, we introduce enteroendocrine chemosensory roles, summarize studies correlating enteroendocrine perturbations with intestinal inflammation and describe the mechanistic interactions by which enteroendocrine and mucosal immune cells interact during disease; highlighting this immunoendocrine axis as a key aspect of innate immunity.

NAFLD, Helicobacter species and the intestinal microbiome

Non-alcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease worldwide. It is well-accepted that gut dysbiosis is associated with NAFLD, however, there is some conflicting evidence regarding the nature of these alterations. Infection with Helicobacter species, mainly H. pylori, has also been associated with increased NAFLD risk, however, some studies have failed to reproduce this finding. Further studies including large study samples and standardised procedures for microbiota analyses, H. pylori detection and NAFLD diagnostic criteria, are required. The mechanisms involving Helicobacter species and the intestinal microbiome in NAFLD pathogenesis appear to be part of the multiple-hit theory, in which increased intestinal permeability, inflammatory responses, altered choline, bile acids and carbohydrate metabolism, production of short-chain fatty acids, urea cycle and urea transport systems, altered maintenance of hepatic γδT-17 cells, insulin resistance, hormones secreted by the adipose tissue, metabolic hormones, bacterial metabolites and Helicobacter toxins, are all implicated.

Impact of the Microbiota and Gastric Disease Development by Helicobacter pylori

Microorganisms in humans form complex communities with important functions and differences in each part of the body. The stomach was considered to be a sterile organ until the discovery of Helicobacter pylori, but nowadays, it is possible to demonstrate that other microorganisms beyond H. pylori can colonize the gastric mucosa and that the diverse microbiota ecosystem of the stomach is different from the mouth and the esophagus, and also from the small intestine and large intestine. H. pylori seems to be the most important member of the gastric microbiota with the highest relative abundance when present, but when it is absent, the stomach has a diverse microbiota. Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, and Fusobacteria are the most abundant phyla in both H. pylori-positive and H. pylori-negative patients. The gastric commensal flora may play some role in the H. pylori-associated carcinogenicity, and differences in the gastric microbiota composition of patients with gastric cancer, intestinal metaplasia, and chronic gastritis are described. The gastric microbiota changed gradually from non-atrophic gastritis to intestinal metaplasia, and to gastric cancer (type intestinal).

Microbes and Cancer

Commensal microorganisms (the microbiota) live on all the surface barriers of our body and are particularly abundant and diverse in the distal gut. The microbiota and its larger host represent a metaorganism in which the cross talk between microbes and host cells is necessary for health, survival, and regulation of physiological functions locally, at the barrier level, and systemically. The ancestral molecular and cellular mechanisms stemming from the earliest interactions between prokaryotes and eukaryotes have evolved to mediate microbe-dependent host physiology and tissue homeostasis, including innate and adaptive resistance to infections and tissue repair. Mostly because of its effects on metabolism, cellular proliferation, inflammation, and immunity, the microbiota regulates cancer at the level of predisposing conditions, initiation, genetic instability, susceptibility to host immune response, progression, comorbidity, and response to therapy. Here, we review the mechanisms underlying the interaction of the microbiota with cancer and the evidence suggesting that the microbiota could be targeted to improve therapy while attenuating adverse reactions.

Other Helicobacters and gastric microbiota

This article aimed to review the literature from 2015 dealing with gastric and enterohepatic non-Helicobacter pylori Helicobacter species (NHPH). A summary of the gastric microbiota interactions with H. pylori is also presented. An extensive number of studies were published during the last year and have led to a better understanding of the pathogenesis of infections with NHPH. These infections are increasingly reported in human patients, including infections with H. cinaedi, mainly characterized by severe bacteremia. Whole-genome sequencing appears to be the most reliable technique for identification of NHPH at species level. Presence of NHPH in laboratory animals may influence the outcome of experiments, making screening and eradication desirable. Vaccination based on UreB proteins or bacterial lysate with CCR4 antagonists as well as oral glutathione supplementation may be promising strategies to dampen the pathogenic effects associated with gastric NHPH infections. Several virulent factors such as outer membrane proteins, phospholipase C-gamma 2, Bak protein, and nickel-binding proteins are associated with colonization of the gastric mucosae and development of gastritis. The development of high-throughput sequencing has led to new insights in the gastric microbiota composition and its interaction with H. pylori. Alterations in the gastric microbiota caused by the pH-increasing effect of a H. pylori infection may increase the risk for gastric cancer.