Effects of Hydrogen Sulfide on the Microbiome: From Toxicity to Therapy Original paper

What was studied?

This review explored the effects of hydrogen sulfide (H₂S) on the gut microbiome, focusing on its dual roles as both a toxin and a therapeutic agent. The study assessed how H₂S, a gaseous signaling molecule produced by both gut bacteria and host cells, influences the microbiota, particularly its ability to modulate inflammation, microbial biofilms, and gut health. The review examined the mechanisms through which H₂S impacts the microbiome, including its influence on microbial diversity, biofilm formation, and its potential to maintain intestinal homeostasis. Additionally, it addressed how different concentrations of H₂S can either exacerbate gut diseases, such as inflammatory bowel disease (IBD), or provide therapeutic benefits by stabilizing microbiota biofilms and reducing inflammation.

Who was studied?

The review does not focus on specific individuals or animals but consolidates findings from a wide range of studies involving both human and animal models. It discusses the role of endogenous and exogenous H₂S in modulating the gut microbiome and its interaction with gut epithelial cells. The review highlights the contributions of both commensal bacteria and pathogenic microorganisms, including Escherichia coli and Helicobacter pylori, in producing H₂S and how this affects the host’s health. Additionally, it emphasizes the need for further research into the effects of dietary H₂S and its potential as a treatment for microbiota-related diseases.

Most important findings

The review identified that H₂S plays a complex role in gut health, with both beneficial and detrimental effects depending on its concentration. High concentrations of H₂S produced by gut bacteria can disrupt the gut’s mucus barrier, impair epithelial integrity, and lead to inflammation, potentially contributing to diseases like IBD. However, at physiological levels, H₂S has anti-inflammatory and cytoprotective properties, stabilizing mucus layers, maintaining microbiota biofilm integrity, and preventing the invasion of pathogenic microorganisms. The review also found that H₂S interacts with the gut microbiota to promote the resolution of inflammation and tissue injury, highlighting its potential as a therapeutic agent. H₂S donors, such as diallyl disulfide (DADS), have been shown to restore the balance of microbiota biofilms and protect against gastrointestinal injury caused by various insults, including NSAIDs and oxidative stress.

Key implications

The findings underscore the dual nature of H₂S in the gut: while high levels can exacerbate gut diseases by disrupting microbiota biofilms and increasing the adhesion of pathogenic microbes, low levels of H₂S produced endogenously or administered exogenously may offer therapeutic benefits. This suggests that H₂S could be used as a targeted therapeutic to restore gut health, especially in conditions like IBD, where microbiota dysbiosis and inflammation play a central role. The review also points to the potential of dietary interventions, such as consuming sulfur-rich foods, to modulate H₂S production in the gut and promote microbiota stability. Future research should focus on understanding the molecular mechanisms behind H₂S’s interaction with the microbiome and its potential to improve treatments for inflammatory and infectious diseases.