02535nas a2200433   4500000000100000000000100001008004100002260001500043653003500058653002300093653002200116100002100138700001800159700001600177700002100193700001600214700001900230700002600249700002400275700002900299700002200328700001900350700001900369700002200388700002100410700002300431700001800454700001900472700001800491700002000509700001700529700001800546700001500564245013500579856005500714300000900769520130900778022001402087       2025                            d  c2025-02-1210aExperimental models of disease10aMolecular medicine10aTumour immunology1 aMattia Ballerini1 aSerena Galiè1 aPunit Tyagi1 aCarlotta Catozzi1 aHariam Raji1 aAmir Nabinejad1 aAngeli D. G. Macandog1 aAlessandro Cordiale1 aBianca Ionela Slivinschi1 aKarol K. Kugiejko1 aMartina Freisa1 aPaola Occhetta1 aJennifer A. Wargo1 aPier F. Ferrucci1 aEmilia Cocorocchio1 aNicola Segata1 aAndrea Vignati1 aAndrey Morgun1 aMichela Deleidi1 aTeresa Manzo1 aMarco Rasponi1 aLuigi Nezi00aA gut-on-a-chip incorporating human faecal samples and peristalsis predicts responses to immune checkpoint inhibitors for melanoma  uhttps://www.nature.com/articles/s41551-024-01318-z  a1-183 aPatient responses to immune checkpoint inhibitors can be influenced by the gastrointestinal microbiome. Mouse models can be used to study microbiome–host crosstalk, yet their utility is constrained by substantial anatomical, functional, immunological and microbial differences between mice and humans. Here we show that a gut-on-a-chip system mimicking the architecture and functionality of the human intestine by including faecal microbiome and peristaltic-like movements recapitulates microbiome–host interactions and predicts responses to immune checkpoint inhibitors in patients with melanoma. The system is composed of a vascular channel seeded with human microvascular endothelial cells and an intestinal channel with intestinal organoids derived from human induced pluripotent stem cells, with the two channels separated by a collagen matrix. By incorporating faecal samples from patients with melanoma into the intestinal channel and by performing multiomic analyses, we uncovered epithelium-specific biomarkers and microbial factors that correlate with clinical outcomes in patients with melanoma and that the microbiome of non-responders has a reduced ability to buffer cellular stress and self-renew. The gut-on-a-chip model may help identify prognostic biomarkers and therapeutic targets.  a2157-846X