Dr. Andrew Kau at BBCon 2024
The breath volatilome is shaped by the gut microbiota
00:00 – The Breath Volatilome is Shaped by the Gut Microbiota
23:48 – Question and answer session
Talk Abstract:
The gut microbiota is widely implicated in host health and disease, inspiring translational efforts to implement our growing body of knowledge in clinical settings. However, the need to characterize gut microbiota by its genomic content limits the feasibility of rapid, point-of-care diagnostics. The microbiota produces a diverse array of xenobiotic metabolites that disseminate into tissues, including volatile organic compounds (VOCs) that may be excreted in breath. We hypothesize that breath contains gut microbe-derived VOCs that inform the composition and metabolic state of the microbiota. To explore this idea, we compared the breath volatilome and fecal gut microbiomes of 27 healthy children and found that breath VOC composition is correlated with gut microbiomes. To experimentally interrogate this finding, we devised a method for capturing exhaled breath from gnotobiotic mice. Breath volatiles are then profiled by gas-chromatography mass-spectrometry (GC-MS). Using this novel methodology, we found that the murine breath profile is markedly shaped by the composition of the gut microbiota. We also find that VOCs produced by gut microbes in pure culture can be identified in vivo in the breath of mice monocolonized with the same bacteria. Altogether, our studies identify microbe-derived VOCs excreted in breath and support a mechanism by which gut bacterial metabolism directly contributes to the mammalian breath VOC profiles.
Speaker Biography:
I am a physician-scientist in the Division of Allergy and Immunology and Center for Women’s Infectious Disease Research at Washington University School of Medicine. My basic and translational research program is directed at understanding how consortia of human microbes that colonize our mucosal surfaces shape human health, particularly in their ability to modify immunity. We are currently engaged in three major, ongoing projects:
- Defining mechanisms by which the gut microbiota influence lung health. We have shown that human gut microbes alter susceptibility to asthma through their ability to alter gut barrier function. We have further expanded on these findings to investigate the gut microbial origins and function of volatile organic compounds found in human breath.
- Investigating the functions of airway commensals in allergic disease. Our prior work has shown that the composition of the airway microbiota in individuals with asthma is enriched for certain species, including Haemophilus. We are presently testing how microbial metabolites produced by Haemophilus influence airway inflammation.
- Developing mucosal vaccines to target uropathogens within the gut. Previous work supports the notion that bacteria that cause urinary tract infections (UTIs) originate in the gut. Based on this observation, we are developing new vaccine strategies to reduce uropathogen colonization in the gut and, ultimately, protect against UTIs.
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