Some Observations on Morphology and Enzyme Activities in Peroral Jejunal Biopsy Specimens

Abstract

Jejunal biopsy specimens were obtained from patients suffering from a variety of intestinal complaints and from a group of normal volunteers. The biopsy specimens were examined under the dissecting microscope and by conventional light microscopy to establish the presence of mucosal abnormality.  A semi quantitave histological technique permitted the degree of change in surface area and mucosal volume to be measured. In order to determine whether functional changes accompanied morphological abnormalities, or indeed whether they might occur in the absence of structural derangements, mucosal enzyme activities were measured, Thus disaccharidase activities, (brush border enzymes) and dipeptidase  activities (cytoplasmic enzymes) were measured, Dipeptidase electrophoretic patterns were obtained to enable alterations in the various molecular forms to be observed, In specific diseases, biochemical and haematological indices were measured to monitor disease activity. The marked histological changes observed in untreated coeliac disease produced reductions in all enzyme activities, especially the disaccharidases. Both morphology and enzyme activities had improved in patients maintained on a gluten-free diet with the exceptions of trehalase, sucrase and gly-leu dipeptidase which remained depressed. Histological abnormalities in the biopsies from coeliac relatives were accompanied by reductions in dipeptidase activities. In the patients with recurrent apthous stomitis gly-leu dipeptidase levels were depressed but other enzyme activities were normal. The reductions of disaccharidase activities in Crohns disease was considered to be a specific microvillous abnormality due to the degree of depression and because of normal cytoplasmic enzyme activities.  The upper jejunum in patients with inactive ulcerative colitis was normal. Patients with persistent diarrhoea exhibited mild histological changes accompanied by reductions in lactase and sucrase activities but patients with only indirect intestinal involvement had normal biopsies, except for an increased mucosal volume, Dipeptidase electrophoretic patterns were only abnormal in the presence of low enzyme activities.