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Published December 2023 | Published
Journal Article Open

Microbe-derived uremic solutes enhance thrombosis potential in the host


p-Cresol sulfate (pCS) and indoxyl sulfate (IS), gut microbiome-derived metabolites, are traditionally associated with cardiovascular disease (CVD) risks in the setting of impaired kidney function. While pharmacologic provision of pCS or IS can promote pro-thrombotic phenotypes, neither the microbial enzymes involved nor direct gut microbial production have been linked to CVD. Untargeted metabolomics was performed on a discovery cohort (n = 1,149) with relatively preserved kidney function, followed by stable isotope-dilution mass spectrometry quantification of pCS and IS in an independent validation cohort (n = 3,954). Genetic engineering of human commensals to produce p-cresol and indole gain-of-function and loss-of-function mutants, followed by colonization of germ-free mice, and studies on host thrombosis were performed. Systemic pCS and IS levels were independently associated with all-cause mortality. Both in vitro and within colonized germ-free mice p-cresol productions were recapitulated by collaboration of two organisms: a Bacteroides strain that converts tyrosine to 4-hydroxyphenylacetate, and a Clostridium strain that decarboxylates 4-hydroxyphenylacetate to p-cresol. We then engineered a single organism, Bacteroides thetaiotaomicron, to produce p-cresol, indole, or both metabolites. Colonizing germ-free mice with engineered strains , we show the gut microbial genes for p-cresol (hpdBCA) and indole (tryptophanase) are sufficient to confer a pro-thrombotic phenotype in vivo . Moreover, human fecal metagenomics analyses show that abundances of hpdBCA and tryptophanase are associated with CVD. These studies show that pCS and IS, two abundant microbiome-derived metabolites, play a broader potential role in CVD than was previously known. They also suggest that therapeutic targeting of gut microbial p-cresol- and indole-producing pathways represent rational targets for CVD.

Copyright and License

© 2023 Nemet et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.


This work is supported by grants from the NIH (NHLBI and Office of Dietary Supplements): P01HL147823 (to S.L.H. and M.A.F.), R01HL103866 (to S.L.H.), R01HL160747 (to I.N.), and R01DK101674 (to M.A.F.); the Leducq Foundation (17CVD01 to S.L.H. and M.A.F.); and Chan Zuckerberg Biohub (to M.A.F.). K.A.R. was supported in part by NIH/NHLBI training grant HL134622. Mass spectrometry studies were performed on instrumentation housed in a facility supported in part through a Shimadzu Center of Excellence.

Data Availability

All source data for figures included in the manuscript were deposited in Zenodo repository (https://zenodo.org/record/8338175). There are restrictions to the availability of some of the clinical data generated in the present study because we do not have permission in our informed consent from research subjects to share data outside our institution without their authorizations. Under these situations, data shared is in summary format.



Additional details

December 21, 2023
January 9, 2024