1. Enterocyte development of microvillus structure has been measured in intestinal biopsies obtained from children suffering from coeliac disease, cow's milk protein intolerance and microvillus atrophy, and the results compared with similar measurements carried out in control children. 2. All types of enteric disease caused a significant 30% reduction in the length of microvilli present on undifferentiated basal crypt enterocytes, here referred to as potential stem cells. 3. Microvillus growth measured in control enterocytes took place mainly over the basal third of the villus. There was then little further change in structure during subsequent enterocyte migration to the villus tip. 4. Microvillus length in diseased tissue remained more or less constant during enterocyte migration to the crypt-villus junction. Microvillus length then decreased slightly during subsequent enterocyte migration over stunted villi. 5. The present results are discussed in relation to the supposed properties of potential stem cells. Comparisons are also made between profiles of microvillus development measured in healthy children and mature adults.
1. Intestinal structure, lactase (β-galactosidase; EC 188.8.131.52) activity and alkaline phosphatase activity have been determined in mouse jejunal and ileal tissues before and during infection with the intestinal parasite Nematospiroides dubius. 2. Oral infection with small numbers of N. dubius larvae caused villus height, crypt depth and enterocyte migration rate to increase in the mouse jejunum. None of these effects occurred in ileal tissue. 3. Lactase activity also increased in jejunal, but not ileal, tissue of infected mice. This increase was associated with a doubling of the rate at which activity appeared in the brush-border membrane of enterocytes during migration over the basal regions of jejunal villi. Alkaline phosphatase activity in jejunal tissue remained unchanged in infected mice. 4. Attention is drawn to the fact that this is the first occasion when crypt cell hyperplasia has been found to be positively correlated with an increase in lactase activity and a decrease in cytotoxic/suppressor T-cells. Further work is needed to establish the primary cause of these effects.
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 α- and β-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 α-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.
1. Graft-versus-host reaction (GvHR) was induced in neonatal mice to produce crypt hyperplasia with and without stunted villi. Lactase activity was measured along individual villi of control and GvHR mice using quantitative cytochemistry. 2. Lactase activity increased in control mice as enterocytes migrated over the lower part of the villus. This increase was followed by a period when lactase activity remained approximately constant. 3. Effects produced by GvHR on this normal profile of development included an extension of the distance on the villus over which enterocytes could continue to increase lactase activity, a reduction in the time needed for an enterocyte to express lactase activity at maximal rate, and an overall decrease in the maximal lactase activity expressed by mature enterocytes. 4. These effects have been quantified by fitting logistic curves to the experimental data. 5. Parallel biochemical analyses of intestinal homogenates showed sucrase, isomaltase, trehalase and maltase activities to increase markedly 7–8 days after the injection of parental spleen cells. 6. Attention is drawn to similarities between these results and steroid induced precocious development of intestinal function in neonatal mice.