Browsing by Subject "Enterocytes"

Now showing 1 - 4 of 4
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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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    Effects of total replacement of fish oil by vegetable oils on n-3 and n-6 polyunsaturated fatty acid desaturation and elongation in sharpsnout seabream (Diplodus puntazzo) hepatocytes and enterocytes
    (Elsevier, 2007-11-26) Almaida Pagán, Pedro Francisco; Hernandez, M. D.; García García, B.; Madrid, Juan A.; Costa, J. de; Mendiola, P.; Fisiología
    The main aim of this work was to determine the impact of total dietary fish oil replacement by vegetable oils on the fatty acid metabolism of sharpsnout seabream hepatocytes and digestive tract enterocytes. Three isonitrogenous (48% crude protein) and isoenergetic (23 MJ/kg) experimental diets were formulated using three different lipid sources: fish oil (FO), rich in n-3 HUFAs; soybean oil (SO), rich in linoleic acid (LA), and linseed oil (LO), especially rich in linolenic acid (LNA). These diets were fed, three times a day to apparent satiation, to triplicate groups of 30 sharpsnout seabream (with an initial average weight of 14.9 g) for nine months at 23.5±1.2 °C. Inclusion of vegetable oils in sharpsnout seabream diet did not have any quantitative nutritional effects on desaturation/elongation of [1-14C] LNA and [1-14C] LA in isolated hepatocytes and total digestive tract enterocytes. Most of the radioactivity found in tissue lipid extracts (94% and 86% for hepatocytes and enterocytes, respectively) using silver nitrate thin-layer chromatography was recovered as [1-14C] C18 PUFA, clearly showing the lack of any significant desaturase/elongase activity in these cells. Only the high levels of HUFA in fish tissues pointed to the existence of some kind of regulatory mechanism, presumably based on HUFA bioaccumulation and C18 PUFA oxidation. Moreover, direct measurements of β-oxidation rates yielded very low values in all cases, the only significant difference being a higher oxidation rate in hepatocytes from fish fed LO versus FO diet.
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    Expression of clusterin in Crohn's disease of the terminal ileum
    (Murcia : F. Hernández, 2001) Gassler, N.; Autschbachl, F.; Heuschen, G.; Witzgal, R.; Otto, H.F.; Obermüller, N.
    Crohn's disease (CD) is a chronic inflammatory intestinal disorder with disturbance and injury of the intestinal mucosal barrier, in which various proinflammatory molecules as well as molecules with antiinflammatory activity and cytoprotective function are found to be expressed. We investigated whether clusterin, a multifunctional cytoprotective protein, is upregulated in Crohn's disease, because augmented expression of clusterin is seen in many organs following various forms of tissue injury. Human actively and inactively inflamed ileal tissues from CD patients as well as normal intestinal specimens from control patients (normal ileum) were investigated by Western blot analysis, immunohistochemisty and in situ hybridization. As compared with controls, a strongly enhanced expression of clusterin was found in CD tissues, correlating with disease activity. Immunohistochemistry and in situ hybridization analysis revealed foci of crypts almost completely lined by clusterin expressing enterocytes in CD, a feature that was never seen in controls. Such crypts appeared especially within the morphologically intact mucosa apart from erosive or ulcerative lesions. Besides epithelia, clusterin was also expressed by inflammatory mononuclear cells. Enhanced expression of clusterin by crypt epithelia might reflect a cytoprotective function of the protein in order to prevent further injury of the intestinal mucosal barrier in CD.
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    Regional variation in ontogeny of class II antigens in enterocytes of mouse small intestine
    (Murcia : F. Hernández, 1992) Sidhu, Nirmal K.; Wrightk, Glenda M.; Markham, R.J. Fred; Singh, Amreek
    The ontogeny of major histocompatibility class I1 antigens in small intestine enterocytes of postnatal C3HlHe mice was investigated. Cryosections of duodenal, jejunal, and ileal segments from 7-, 14-, 16-, 20-, 21-, 23-, 25-, 27-, 28-day-old and 7-week-old mice were stained for the class I1 antigens with MRC OX6 monoclonal antibodies by peroxidase-antiperoxidase labelling. In adults, the duodenum exhibited least expression of class I1 antigens that increased progressively towards the ileum. The expression in the villous epithelium was first seen in the duodenum and jejunum 21 days after birth but the ileal enterocytes did not exhibit any class I1 antigens. The earliest appearance (21 days postnatal) of class 11 antigens in the enterocytes coincides with the age of weaning which suggests that immunologic stimulation by ingested antigens after weaning may influence expression of these antigens. At day 28 after birth, the duodenum and jejunum expressed levels comparable to those in the adults. The first expression of the antigens seen in the ileum was at day 28 postpartum. Crypt epithelium of the three regions of the small intestine showed expression similar to that of corresponding regional villous enterocytes. We conclude that there is an age-dependent regional variation in the expression of class I1 antigens in enterocytes, and the expression increases with age. The variation in expression of the class I1 antigens in enterocytes of postnatal mice is attributed to the developmental status of the tissue. The nature of postnatal expression of the antigens is important since an early appearance of these antigens may have implications in autoimmunity.