MADCAM1 and colitis: In so doing, we found that the most potent substrate is cysteamine which has been shown to induce colitis and colonic cancer in mice;27–30 an intestinal phenotype mirrored clinically in patients with PSC.1–3 Furthermore, cysteamine when administered to hepatic endothelium resulted in increased MAdCAM-1 expression and an enhanced ability to recruit α4β7+ cells under flow.