Browsing by Subject "Intestinal epithelium"

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    Adaptive remodelling of intestinal epithelium assessed using stereology: correlation of single cell and whole organ data with nutrient transport
    (Murcia : F. Hernández, 1996) Mayhew, T.M.
    Adaptation in the intestinal epithelium depends on cell number and the properties of individual cells but these responses operate within different time frames. Changes in number take days to accomplish but those in behaviour may occur within hours. This article reviews the value of stereology for characterising structural features of the average enterocyte and the entire organ (mammalian small intestine or avian lower intestine) during adaptation. Stereological data are correlated with the physiology and molecular biology of glucose and Na+ transpon. In small intestine, account is taken of vertical (crypt-villus) and longitudinal (craniocaudal) gradients and of adaptations to chemically-induced diabetes and diet. Results show that longer-term adaptation depends critically on epithelial renewal. In diabetic small intestine, changes in glucose transport are accompanied by changes in the number, but not morphology, of villous enterocytes. In avian lower intestine, increased Na+ transport requires changes in cell number and the extent of their apical, but not basolateral, membrane surfaces. These changes allow opportunities to incorporate more (or more active) transport sites in apical and basolateral membrane domains of individual cells and of whole organs.
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    Glucose-mediated cytoprotection in the gut epithelium under ischemic and hypoxic stress
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2017) Huang, Chung Yen; Pai, Yu Chen; Yu, Linda Chia Hui
    Single-layered intestinal epithelia play key roles in the maintenance of gut homeostasis and barrier integrity. Various types of epithelial cell death, including apoptosis, necrosis, and necroptosis, have been detected in ischemic and hypoxic stress conditions, thus resulting in bacterial translocation and gut-derived septic complications. Cytoprotective strategies, such as enteral glucose uptake, rescue intestinal epithelium from cell death after ischemic and hypoxic injury. Although glucose metabolism and energy production are generally considered to be the key factors in cytoprotection, the precise modes and sites of action have not been clarified. Our recent studies have demonstrated that energy restoration promotes crypt hyperplasia but does not prevent epithelial cell death under ischemic stress. On the other hand, glycolytic pyruvate prevents epithelial cells from undergoing apoptosis and necroptosis by scavenging free radicals in an ATP-independent manner. Distinct gut protective mechanisms involving ATP, pyruvate, glucose metabolic enzymes, and sodiumdependent glucose transporter activation are discussed here. Overall, glucose-mediated cytoprotection may be a universal mechanism that has evolved in epithelial cells for the maintenance of intestinal homeostasis. Enteral glucose supplementation is beneficial as a perioperative supportive therapy for the protection of gut barrier integrity.