Preliminary study on the activities of terminal ileum mucosal brush border peptidase and disaccharidase in children with persistent diarrhea and chronic diarrhea

Objective To investigate the changes of terminal ileum brush border peptidase and disaccharidase activities in persistent diarrhea and chronic diarrhea children.To investigate the relationship between ileum mucosal histology and the ileal brush border peptidase and disaccharidase activities.Methods The terminal ileal mucosal specimens were collected from children who were taken enteroscopy during July 2007 to March 2008 in our hospital.Two ileal mucosal specimens were obtained from the terminal ileum endoscopically.One was stored intact at-80℃ for assaying of brush border peptidases and disaccharidase activities,and another was placed in 10% formalin for histologic examination.All children were divided into two groups,persisting diarrhea and chronic diarrhea group and non-diarrhea group.The terminal ileal mucosal histologic changes were graded according to the Marsh classification as follows: normal villus,mild villous atrophy,moderate villous atrophy and severe villus atrophy.If there was no villous atrophy,they were classified into two groups according to McHugh : normal terminal ileum mucosa and chronically inflamed terminal ileum mucosa.The ileal brush border peptidase and disaccharidase activities of persistent diarrhea and chronic diarrhea group were compared to non-diarrhea group with normal mucosa.Protein concentrations in homogenates were determined according to the method of BCA.Enzyme activities in homogenates were expressed as international units per gram of protein.One unit corresponded to the hydrolysis of 1 μmol of substrate per minute under the assay conditions.All data were analyzed by SPSS version 14.The normality of brush border disaccharidases activities were determined by Kolmogorov-Smirnov test,if the data were not normally distributed,a logarithmic transformation was performed to normalize the data.All the results were represented as mean±standard deviation.Differences between groups were determined by two-group t-test,P values 0.05 was considered to be significant.Results Terminal ileal mucosal specimens were collected from 27 children,12 chilidren were persistent diarrhea and chronic diarrheas.Fifteen children were non-diarrhea group who accepted colonoscopy owing to the gastrointestinal symptoms such as hemafecia,abdominal pain,swollen,polypus,pale,etc.Of the 27 children,20 were boys and 7 were girls(2.86∶1).Ages ranged from 1 to 12 years(mean age,5 years).All ileal mucosal villi were normal,but there were 17 children with normal terminal ileum mucosa and 10 children with chronically inflamed terminal ileum mucosa.In the diarrhea group,there were 6 children with normal mucosa and 6 children with chronically inflamed mucosa.In other disease group,there were 11 children with normal mucosa and 4 children with chronically inflamed mucosa.No differences statistically in ileum peptidase and disaccharidases activity values were observed between diarrhea group and control group.No differences statistically in ileum brush border peptidase and disaccharidases activity values were observed between normal terminal ileum mucosa and chronically inflamed terminal ileum mucosa.Conclusions The level of ileal mucosa peptidase and disaccharidases activities were not changes in persistent diarrhea and chronic diarrhea children with normal villi.There were no obvious changes in the level of peptidase and disaccharidases activities in chronically inflamed terminal ileum mucosa if the villus was normal.