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Selective alteration of brush-border hydrolases in intestinal diseases in childhood
A D Phillips1, M W Smith, J A Walker-Smith
1Queen Elizabeth Hospital for Children, London, U.K.
Insights
Children with coeliac disease show pronounced lactase deficiency, impacting intestinal enzyme activity. These findings highlight specific hydrolase changes in pediatric gastrointestinal disorders.
Area of Science:
- Gastroenterology
- Biochemistry
- Pediatric Medicine
Background:
- Intestinal enzyme deficiencies are common in pediatric gastrointestinal disorders.
- Understanding hydrolase activity is crucial for diagnosing and managing conditions like coeliac disease.
- Previous studies have indicated altered enzyme levels in diseased intestinal tissue.
Purpose of the Study:
- To compare lactase, sucrase, and maltase activities in normal intestinal biopsies versus those from children with coeliac disease, cow's milk protein intolerance, and intractable diarrhoea.
- To investigate disease-induced changes in enterocyte enzyme expression along villi.
- To analyze the developmental time course of hydrolase enzymes in normal and coeliac intestinal tissue.
Main Methods:
- Biochemical assays of lactase, sucrase, and maltase activities on intestinal biopsies.
- Quantitative cytochemical investigations of enterocyte enzyme expression (alpha- and beta-glucosidases, alkaline phosphatase).
- Comparative analysis of enzyme activity time courses in normal and coeliac tissues.
Main Results:
- Lactase deficiency was more pronounced than sucrase or maltase deficiencies in affected children.
- Disease-induced changes were observed in enterocyte expression of alpha- and beta-glucosidases, but not alkaline phosphatase, along stunted villi.
- The initial rate of lactase appearance was halved in coeliac patients, while alpha-glucosidase development remained constant and alkaline phosphatase increased significantly.
Conclusions:
- Lactase deficiency is a prominent feature in pediatric intestinal disorders studied.
- Enterocyte migration and differentiation exhibit disease-specific alterations in enzyme expression.
- Enteroblastic replacement does not fully explain hydrolase deficiencies observed in diseased intestines.
Abstract:
1. Biochemical estimates of lactase, sucrase and maltase activities, carried out on intestinal biopsies appearing histologically normal, were compared with those obtained from children suffering from coeliac disease, cow's milk protein intolerance/postenteritis syndrome and the intractable diarrhoea syndrome of infancy. Lactase deficiency in these children was found to be more pronounced than sucrase or maltase deficiencies. 2. Quantitative cytochemical investigations showed characteristic disease-induced changes in the ability of enterocytes to express alpha- and beta-glucosidases, but not alkaline phosphatase activities, during migration along stunted villi. 3. Separate estimates of the time course describing hydrolase development in normal and coeliac tissue showed the initial rate of lactase appearance to be halved in coeliac patients, while that for alpha-glucosidases remained constant and that for alkaline phosphatase increased by a factor of four. Enteroblastic replacement of mature enterocytes cannot provide a general explanation for hydrolase deficiency in diseased intestine.