Gastric microbiota transplantation as a potential treatment for immune checkpoint inhibitor-associated gastritis

Abstract

Immune-related adverse events (irAEs) are complications of the use of immune checkpoint inhibitors (ICIs). ICI-associated gastritis is one of the main irAEs. The gastric microbiota is often related to the occurrence and development of many gastric diseases. Gastric microbiota adjustment may be used to treat gastric disorders in the future. Faecal microbiota transplantation can alter the gut microbiota of patients and has been used for treating ICI-associated colitis. Therefore, we propose gastric microbiota transplantation as a supplementary treatment for patients with ICI-associated gastritis who do not respond well to conventional therapy.

Key Words: Immune checkpoint inhibitor, Immune-related adverse events, Gastritis, Gastric microbiota transplantation, Probiotics

Core Tip: The gastric microbiota is often related to the occurrence and development of many gastric diseases. Faecal microbiota transplantation has been used for treating immune checkpoint inhibitor (ICI)-associated colitis. Therefore, gastric microbiota transplantation is a promising treatment for ICI-associated gastritis.

TO THE EDITOR

We read with interest this editorial by Lin et al[1], who comprehensively introduced therapeutic strategies for immune checkpoint inhibitor (ICI)-associated gastritis. ICI-associated gastroenteritis is often reported among immune-related adverse events (irAEs). Despite the currently low incidence of ICI-associated gastritis, we still need to consider the importance of this irAE. Conventional treatments, including the interruption of ICI therapy and the use of proton pump inhibitors, glucocorticoids (such as prednisone) and immunosuppressive agents, can improve the condition of most patients with ICI-associated gastritis in most cases.

The gastric microbiota is often related to the occurrence and development of many gastric diseases[2]. Therefore, gastric microbiota adjustment may become an important method for treating gastric disorders in the future. Faecal microbiota transplantation (FMT) has recently been applied in the treatment of ICI-induced colitis. Several patients suffering from ICI-induced colitis have achieved clinical remission successfully through FMT, in which the gut microbiota from healthy donors is transferred to patients, thereby altering the baseline microbial diversity and microbiome composition of recipients[3]. Therefore, for patients who do not respond well to the above conventional measures, we propose gastric microbiota transplantation (GMT) as a new treatment.

First, oral probiotics can serve as a form of GMT. As living microorganisms, probiotics are beneficial to human health and are often used to treat gastrointestinal diseases. Chen et al[4] demonstrated that the probiotic Lactobacillus spp. can combat Helicobacter pylori (H. pylori)-induced inflammation by decreasing H. pylori-induced production of IL-8. The main mechanisms by which probiotics antagonize H. pylori include secreting antimicrobial substances, competing for binding sites, repairing the gastric mucosal barrier, and regulating immunity[5]. However, some probiotics may be killed by stomach acid, so it is necessary to consider ways to process probiotics or develop more acid-resistant probiotics to increase the colonization rate in the stomach.

Second, in a study conducted by Kwon et al[6], the gastric microbiota of human patients suffering from various gastric diseases was transplanted into germ-free mice, which served as animal models of gastric disease. Another study aimed to investigate the impact of the colonic microbiota, colonic content filtrate, and gastric microbiota on gut health by transplanting them into recipient piglets[7]. Although there is currently a lack of experiments and studies, it is feasible to transplant the gastric microbiota from healthy people into a patient’s stomach to alter their gastric microbiota.

In conclusion, GMT is expected to regulate and restore the balance of the gastric microbiota and may become a new therapeutic approach for ICI-associated gastritis.