Beyond Helicobacter: dealing with other variants of gastritis-an algorithmic approach

RE.GA.IN.: the Real-world Gastritis Initiative-updating the updates

At the end of the last century, a far-sighted 'working party' held in Sydney, Australia addressed the clinicopathological issues related to gastric inflammatory diseases. A few years later, an international conference held in Houston, Texas, USA critically updated the seminal Sydney classification. In line with these initiatives, Kyoto Global Consensus Report, flanked by the Maastricht-Florence conferences, added new clinical evidence to the gastritis clinicopathological puzzle.The most relevant topics related to the gastric inflammatory diseases have been addressed by the Real-world Gastritis Initiative (RE.GA.IN.), from disease definitions to the clinical diagnosis and prognosis. This paper reports the conclusions of the RE.GA.IN. consensus process, which culminated in Venice in November 2022 after more than 8 months of intense global scientific deliberations. A forum of gastritis scholars from five continents participated in the multidisciplinary RE.GA.IN. consensus. After lively debates on the most controversial aspects of the gastritis spectrum, the RE.GA.IN. Faculty amalgamated complementary knowledge to distil patient-centred, evidence-based statements to assist health professionals in their real-world clinical practice. The sections of this report focus on: the epidemiology of gastritis; Helicobacter pylori as dominant aetiology of environmental gastritis and as the most important determinant of the gastric oncogenetic field; the evolving knowledge on gastric autoimmunity; the clinicopathological relevance of gastric microbiota; the new diagnostic horizons of endoscopy; and the clinical priority of histologically reporting gastritis in terms of staging. The ultimate goal of RE.GA.IN. was and remains the promotion of further improvement in the clinical management of patients with gastritis.

Helicobacter pylori-negative Chronic Gastritis in Children: A Systematic Review

OBJECTIVES

To systematically review the current evidence on Helicobacter pylori-negative chronic gastritis including natural history, available therapies and outcomes.

METHODS

Articles providing data on the prevalence, treatment or outcomes of Helicobacter pylori-negative gastritis were identified through a systematic search in the MEDLINE and EMBASE databases. All original research articles from human studies until October 31, 2021, were included.

RESULTS

A total of 54 studies were included consisted of eosinophilic gastritis (n = 9), autoimmune gastritis (n = 11), collagenous gastritis (n = 16), focally enhanced gastritis (n = 6), lymphocytic gastritis (n = 5) and other causes including idiopathic gastritis and chronic renal failure related (n = 7). Most of the included studies were either cross-sectional or longitudinal cohorts except for collagenous gastritis, which mainly included case reports and case series. The prevalence of paediatric eosinophilic gastritis ranges between 5 and 7/100,000 and patients have generally favourable outcome with 50% to 70% clinical and histological response to either corticosteroids or elimination diets. Autoimmune gastritis and collagenous gastritis are extremely rare entities, commonly present with refractory iron deficiency anaemia, while lymphocytic gastritis is relatively common (10%-45%) in children with coeliac disease. Data on treatments and outcomes of autoimmune, collagenous, and focally enhanced gastritis are lacking with limited data implying poor response to therapy in the former 2 diagnoses.

CONCLUSIONS

Helicobacter pylori-negative gastritis is uncommonly reported, mainly in small cohorts, mixed adult-paediatric cohorts or as sporadic case reports. As common symptoms are not specific, thus not always result in an endoscopic evaluation, the true prevalence of these distinct disorders may be underestimated, and thus under reported.

Glucocorticoids and Androgens Protect From Gastric Metaplasia by Suppressing Group 2 Innate Lymphoid Cell Activation

BACKGROUND & AIMS

The immune compartment is critical for maintaining tissue homeostasis. A weak immune response increases susceptibility to infection, but immune hyperactivation causes tissue damage, and chronic inflammation may lead to cancer development. In the stomach, inflammation damages the gastric glands and drives the development of potentially preneoplastic metaplasia. Glucocorticoids are potent anti-inflammatory steroid hormones that are required to suppress gastric inflammation and metaplasia. However, these hormones function differently in males and females. Here, we investigate the impact of sex on the regulation of gastric inflammation.

METHODS

Endogenous glucocorticoids and male sex hormones were removed from mice using adrenalectomy and castration, respectively. Mice were treated with 5α-dihydrotestosterone (DHT) to test the effects of androgens on regulating gastric inflammation. Single-cell RNA sequencing of gastric leukocytes was used to identify the leukocyte populations that were the direct targets of androgen signaling. Type 2 innate lymphoid cells (ILC2s) were depleted by treatment with CD90.2 antibodies.

RESULTS

We show that adrenalectomized female mice develop spontaneous gastric inflammation and spasmolytic polypeptide-expressing metaplasia (SPEM) but that the stomachs of adrenalectomized male mice remain quantitatively normal. Simultaneous depletion of glucocorticoids and sex hormones abolished the male-protective effects and triggered spontaneous pathogenic gastric inflammation and SPEM. Treatment of female mice with DHT prevented gastric inflammation and SPEM development when administered concurrent with adrenalectomy and also reversed the pathology when administered after disease onset. Single-cell RNAseq of gastric leukocytes revealed that ILC2s expressed abundant levels of both the glucocorticoid receptor (Gr) and androgen receptor (Ar). We demonstrated that DHT treatment potently suppressed the expression of the proinflammatory cytokines Il13 and Csf2 by ILC2s. Moreover, ILC2 depletion protected the stomach from SPEM development.

CONCLUSIONS

Here, we report a novel mechanism by which glucocorticoids and androgens exert overlapping effects to regulate gastric inflammation. Androgen signaling within ILC2s prevents their pathogenic activation by suppressing the transcription of proinflammatory cytokines. This work revealed a critical role for sex hormones in regulating gastric inflammation and metaplasia.