Intestinal interstitial fluid isolation provides novel insight into the human host-microbiome interface

Avery EG, Haag LM, McParland V, Kedziora SM, Zigra GJ, Valdes DS, Kirchner M, Popp O, Geisberger S, Nonn O, Karlsen TV, N’Diaye G, Yarritu A, Bartolomaeus H, Bartolomaeus TU, Tagiyeva NA, Wimmer MI, Haase N, Zhang YD, Wilhelm A, Grütz G, Tenstad O, Wilck N, Forslund SK, Klopfleisch R, Kühl AA, Atreya R, Kempa S, Mertins P, Siegmund B, Wiig H, Müller DN (2025)

Publication Language: English

Publication Type: Journal article

Publication year: 2025

Journal

Cardiovascular Research Oxford University Press

Book Volume: 121

Pages Range: 803-816

Journal Issue: 5

DOI: 10.1093/cvr/cvae267

Abstract

Aims The gastrointestinal (GI) tract is composed of distinct sub-regions, which exhibit segment-specific differences in microbial colonization and (patho)physiological characteristics. Gut microbes can be collectively considered as an active endocrine organ. Microbes produce metabolites, which can be taken up by the host and can actively communicate with the immune cells in the gut lamina propria with consequences for cardiovascular health. Variation in bacterial load and composition along the GI tract may influence the mucosal microenvironment and thus be reflected its interstitial fluid (IF). Characterization of the segment-specific microenvironment is challenging and largely unexplored because of lack of available tools Methods Here, we developed methods, namely tissue centrifugation and elution, to collect IF from the mucosa of different intestinal segments. and results These methods were first validated in rats and mice, and the tissue elution method was subsequently translated for use in humans. These new methods allowed us to quantify microbiota-derived metabolites, mucosa-derived cytokines, and proteins at their site-of-action. Quantification of short-chain fatty acids showed enrichment in the colonic IF. Metabolite and cytokine analyses revealed differential abundances within segments, often significantly increased compared to plasma, and proteomics revealed that proteins annotated to the extracellular phase were site-specifically identifiable in IF. Lipopolysaccharide injections in rats showed significantly higher ileal IL-1β levels in IF compared to the systemic circulation, suggesting the potential of local as well as systemic effect. Conclusion Collection of IF from defined segments and the direct measurement of mediators at the site-of-action in rodents and humans bypasses the limitations of indirect analysis of faecal samples or serum, providing direct insight into this understudied compartment.

Authors with CRIS profile

Raja Atreya Professur für Translationale Immunforschung bei chronisch entzündlichen Darmerkrankungen

Involved external institutions

Max-Delbrück-Centrum für Molekulare Medizin / Max Delbrück Center for Molecular Medicine (MDC) Berlin-Buch DE Germany (DE) Berliner Institut für Gesundheitsforschung (BIH) DE Germany (DE) CheckImmune GmbH DE Germany (DE) Charité - Universitätsmedizin Berlin DE Germany (DE) Freie Universität Berlin DE Germany (DE) University of Bergen / Universitetet i Bergen NO Norway (NO)

How to cite

APA:

Avery, E.G., Haag, L.M., McParland, V., Kedziora, S.M., Zigra, G.J., Valdes, D.S.,... Müller, D.N. (2025). Intestinal interstitial fluid isolation provides novel insight into the human host-microbiome interface. Cardiovascular Research, 121(5), 803-816. https://doi.org/10.1093/cvr/cvae267

MLA:

Avery, Ellen G., et al. "Intestinal interstitial fluid isolation provides novel insight into the human host-microbiome interface." Cardiovascular Research 121.5 (2025): 803-816.

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