Zonulin is a protein involved in the regulation of intestinal permeability by the regulation of intestinal tight junctions. Zonulin can be used as a biomarker of gastrointestinal function and inflammation in several diseases. A study in critical care patients noted a a significant association with zonulin and delayed gastric emptying, noting that zonulin increases intestinal permeability of the small intestine related to immune activated mucosal barrier impairment and linked this to gastric dysmotility.
References:
Fasano A. Zonulin, regulation of tight junctions, and autoimmune diseases. Ann N Y Acad Sci 2012 Jul;1258(1):25e33.
Greis C, Rasuly Z, Janosi RA, Kordelas L, Beelen DW, Liebregts T. Intestinal T lymphocyte homing is associated with gastric emptying and epithelial barrier function in critically ill: a prospective observational study. Crit Care 2017 Mar 22;21(1):70.