Analytical Subcellular Fractionation of Jejunal Biopsy Specimens: Enzyme Activities, Organelle Pathology and Response to Gluten Withdrawal in Patients with Coeliac Disease

Abstract

1. Portions of jejunal biopsy specimens from patients with coeliac disease were homogenized in isotonic sucrose solution and subjected to analytical subcellular fractionation by sucrose-densitygradient centrifugation.2. The activities and distribution of marker enzymes for the principal subcellular organelles were determined by highly sensitive enzymic microassays employing fluorigenic and radiolabelled substrates.3. In untreated coeliac disease the brush border showed decreased activities of five marker enzymes, which were reduced to up to one-eighth of control values. On sucrose density gradients the distinct brush-border peak at density 1.21 was replaced by a broad peak at density 1-16.4. Two out of three lysosomal enzymes showed increased activities and there was evidence of enhanced fragility of both lysosomes and peroxisomes.5. There were reduced activities of both mitochondria1 and cytosol malate dehydrogenase, with increased activities of cytosol lactate dehydrogenase.6. The endoplasmic reticulum and basal-lateral membranes were relatively unaffected except that the equilibrium densities were slightly increased and decreased respectively.

Jejunal mucosal enzyme activities, regulatory peptides and organelle pathology of the enteropathy of common variable immunodeficiency.

“…A similar phenomenon is noted in coeliac disease, where it has been suggested to be of pathogenic significance. 6 The present study, however, has shown that the lysosomal enzyme changes characteristic of coeliac disease3 are not found in common variable immunodeficiency. Because changes in this organelle are more likely to be involved in the pathogenesis of the more profound mucosal lesion of coeliac disease it is probable that the changes in 3-glucosidase noted in the present study are secondary to the mucosal damage.…”

Dietary modulation of gluten sensitivity in a naturally occurring enteropathy of Irish setter dogs.

“…'9 This finding is in marked contrast to the situation in coeliac disease where activities of disaccharidases are invariably low and may not recover fully for several months after gluten withdrawal. 25 In the normal diet group, permeability to "'Cr-EDTA decreased significantly with the introduction of the gluten free diet, but was still high when compared with controls. The persistence of the defect in intestinal permeability in this group, after recovery on a gluten free diet, is in agreement with the finding of raised permeability, in the absence of obvious intestinal damage, in littermates reared on a cereal free diet.20 Gluten challenge in the normal diet group resulted in an increase in intestinal permeability, probably secondary to the recurrence of intestinal damage, whereas in the cereal free diet group it produced no change in the permeability, as might be expected by the minimal morphological and biochemical changes seen.…”

Evaluation of differential disaccharide excretion in urine for non-invasive investigation of altered intestinal disaccharidase activity caused by alpha-glucosidase inhibition, primary hypolactasia, and coeliac disease.

“…In vitro assay of intestinal biopsy tissue usually demonstrates the presence of lactase deficiency in coeliac disease regardless of treatment. 32 The contract between estimates of intestinal disaccharidase activity in coeliac disease by in vitro assay of jejunal tissue and disaccharide hydrolysis assessed in vivo by the disaccharide ratio test is therefore a matter of interest and importance. Ratios of urinary disaccharide excretion, which are not affected by overall variations in monosaccharide transport capacity or permeability to disaccharide, suggest that impairment of intestinal disaccharide hydrolysis may be less prevalent in coeliac disease than suggested by the jejunal disaccharidase assays.…”