Emerging role of hydrogen sulfide in colonic physiology and pathophysiology

Abstract

Hydrogen sulfide (H₂S) is a toxic gas that is now recognized as an important mediator of many physiological processes. In the colon, H₂S is produced both endogenously and by naturally occurring sulfate-reducing bacteria (SRB). The full arrays of its effects in the gastrointestinal tract are still being elucidated, but they range from motility to carcinogenesis. We examined the evidence relating to H₂S as a modulator of colonic function and disease. H₂S is implicated in modulation of colonic compliance through its action on smooth muscle. There is also evidence linking H₂S to colonic nociception, inflammatory bowel disease (IBD), and colorectal cancer. The exact mechanisms and pathways by which H₂S exerts its multitude of effects are not yet fully understood, but its involvement in physiological and pathophysiological conditions of the colon is becoming evident. Elucidating the intricate effects of H₂S in the colon and understanding the exact nature of its interactions with the colon makes pharmacological modulation of H₂S production and metabolism potential targets for treatment of a multitude of colonic conditions in the future.

Hydrogen Sulfide Is an Endogenous Potentiator of T Cell Activation

“…H 2 S is continually produced by luminal sulfate-reducing commensal bacteria in the colon and is normally detoxified by rhodanese in the surrounding mucosal cells to thiosulfate (65,66). An increase in the steady state H 2 S levels either from overproduction or reduced consumption is thought to play a role in the etiology of inflammatory bowel disease and related cancers (67). Our data provide a logical link between these reports in that the excess H 2 S could contribute to unwanted T cell activation toward commensal H 2 S-producing bacteria.…”

Habitat degradation impacts black howler monkey (Alouatta pigra) gastrointestinal microbiomes

“…Butyrogenic and acetogenic metabolism are particularly beneficial as they allow optimal energy gain, and butyrate promotes intestinal development and health (Donohoe et al, 2011;Grootaert et al, 2011). In contrast, sulfate-reducing bacteria represent a less desirable group of hydrogen-utilizers, whose endproduct H 2 S can provoke carcinogenesis and inflammation (Medani et al, 2011;Carbonero et al, 2012). Thus, high butyrogenic and acetogenic metabolism indicate potentially healthier microbiomes in CR while both captive and FR howlers present less fermentative potential along with high numbers of potentially harmful sulfate-reducing bacteria.…”

“…Instead, hydrogenotrophy in captives appeared to be facilitated by sulfate-reducing bacteria, which dissipate dihydrogen through the production of hydrogen sulfide (H 2 S). Hydrogen sulfide is a toxic gas that affects smooth muscle and has been linked to colonic nociception, inflammatory bowel disease and colorectal cancer (Medani et al, 2011;Carbonero et al, 2012). Desulfovibrionales, the prominent intestinal sulfate-reducing bacteria order, were most abundant in the FR and captive groups and rare in the CR and SD (Table 2).…”

Hydrogen sulfide (H2S) and hypoxia inhibit salmonid gastrointestinal motility: evidence for H2S as an oxygen sensor

“…Both pathological and physiological attributes have been ascribed to H 2 S in the GI tract (Wallace, 2010). H 2 S has been suggested to contribute to a variety of intestinal disorders including ulcerative colitis, inflammatory bowel disease and colorectal cancer (Attene-Ramos et al, 2010;Medani et al, 2010;Rowan et al, 2009). Conversely, H 2 S has been shown to have antiinflammatory and antinociceptive actions in the GI tract and H 2 S 'releasing' compounds have been added to non-steroidal antiinflammatory drugs (NSAIDs) to prevent gastric irritation and promote healing of ulcers (Wallace, 2010;Wallace et al, 2007).…”