Fast intestinal barrier recovery following ischemia/reperfusion damage in the human gut: myosin light chain mediated closure of the villus tip

Abstract

In a recently developed human model of intestinal ischemia reperfusion (I‐IR) a rapid reversal of intestinal damage by shedding of injured enterocytes and villus tip closure was described. Here we investigated the putative involvement of myosin light chain kinase (MLCK) mediated actin contraction in villus tip closure.During surgery, an isolated part of the jejunum scheduled to be removed was subjected to 30 min ischemia and subsequent reperfusion. Immunohistochemistry was used to study the localization of MLCK, phosphorylated‐MLC (pMLC), filamentous actin and claudin‐3. Protein levels of MLCK, pMLC and claudin‐3 were semi‐quantitatively analyzed using western blot. Intestinal claudin‐3 production was determined by qPCR.After 30 min ischemia subepithelial spaces were noted as retractions of the basal membrane. A 30 min reperfusion period resulted in disintegration of epithelial lining at the villus tip, with epithelial cell damage and loss of claudin‐3. Both MLCK and pMLC increased following ischemia and were distributed around the disrupted villus tips after 30 min of reperfusion (MLCK; 918±430 versus 641±338 INT, P<0.01) (fig 1). After 60 min reperfusion complete barrier recovery was observed.This study shows fast gut barrier recovery following I‐IR damage in the human gut after myosin light chain kinase mediated closure of the villus tip.Figure 1A) Before ischemiaB) After 30 min ischemiaC) After 30 min reperfusionD) After 60 min reperfusion