Intestinal alkaline phosphatase in the colonic mucosa of children with inflammatory bowel disease

AIM:To investigate intestinal alkaline phosphatase(iAP) in the intestinal mucosa of children with inflammatory bowel disease(IBD).METHODS:Colonic biopsy samples were taken from 15 newly diagnosed IBD patients and from 10 healthy controls.In IBD patients,specimens were obtainedboth from inflamed and non-inflamed areas.The iAP mRNA and protein expression was determined by reverse transcription-polymerase chain reaction and Western blotting analysis,respectively.Tissue localization of iAP and Toll-like receptor(TLR) 4 was investigated by immunofluorescent staining.RESULTS:The iAP protein level in the inflamed mucosa of children with Crohn's disease(CD) and ulcerative colitis(UC) was significantly decreased when compared with controls(both P < 0.05).Similarly,we found a significantly decreased level of iAP protein in the inflamed mucosa in CD compared with non-inflamed mucosa in CD(P < 0.05).In addition,the iAP protein level in inflamed colonic mucosa in patients with UC was decreased compared with non-inflamed mucosa in patients with CD(P < 0.05).iAP protein levels in the non-inflamed mucosa of patients with CD were similar to controls.iAP mRNA expression in inflamed colonic mucosa of children with CD and UC was not significantly different from that in non-inflamed colonic mucosa with CD.Expression of iAP mRNA in patients with noninflamed mucosa and in controls were similar.Co-localization of iAP with TLR4 showed intense staining with a dotted-like pattern.iAP was present in the inflamed and non-inflamed mucosa of patients with CD,UC,and in control biopsy specimens,irrespective of whether it was present in the terminal ileum or in the colon.However,the fluorescent signal of TLR4 was more pronounced in the colon compared with the terminal ileum in all groups studied.CONCLUSION:Lower than normal iAP protein levels in inflamed mucosa of IBD patients may indicate a role for iAP in inflammatory lesions in IBD.Based on our results,administration of exogenous iAP enzyme to patients with the active form of IBD may be a therapeutic option.

Increased duodenal expression of mi R-146a and-155 in pediatric Crohn's disease

AIM: To evaluate the role of micro RNA(mi R)-146 a,-155 and-122 in the duodenal mucosa of pediatric patients with Crohn's disease(CD) and the effect of transforming growth factor-β(TGF-β) on these mi Rs in duodenal epithelial and fibroblast cells.METHODS: Formalin-fixed, paraffin-embedded biopsies derived from the macroscopically inflamed(CD inflamed: n = 10) and intact(CD intact: n = 10) duodenal mucosa of pediatric CD patients and control children(C: n = 10) were examined. Expression of mi R-146 a,-155 and-122 was determined by realtime polymerase-chain reaction(PCR). The expression of the above mi Rs was investigated in recombinant human TGF-β(1 nmol/L, 24 h) or vehicle treated small intestinal epithelial cells(CCL-241) and primary duodenal fibroblast cells derived from healthy children as well.RESULTS: Expression of mi R-146 a was significantly higher in the inflamed duodenal mucosa compared to the intact duodenal mucosa of children with CD(CD inflamed: 3.21 ± 0.50 vs CD intact: 0.62 ± 0.26, p ≤ 0.01) and to the control group(CD inflamed: 3.21 ± 0.50 vs C: 1.00 ± 0.33, p ≤ 0.05). The expression of mi R-155 was significantly increased in the inflamed region of the duodenum compared to the control group(CD inflamed: 4.87 ± 1.02 vs Control: 1.00 ± 0.40, p ≤ 0.001). The expression of mi R-122 was unchanged in the inflamed or intact mucosa of CD patients compared to controls. TGF-β treatment significantly decreased the expression of mi R-155 in small intestinal epithelial cells(TGF-β: 0.7 ± 0.083 vs Control: 1 ± 0.09, p ≤ 0.05) and also the expression of mi R-146a(TGF-β: 0.67 ± 0.04 vs Control: 1 ± 0.15, p ≤ 0.01) and mi R-155(TGF-β: 0.72 ± 0.09 vs Control: 1 ± 0.06, p ≤ 0.05) in primary duodenal fibroblasts compared to corresponding vehicle treated controls. TGF-β treatment did not influence the expression of mi R-122.CONCLUSION: The elevated expression of mi R-146 a and-155 in the inflamed duodenal mucosa of CD patients suggests the role of these mi Rs in the pathomechanism of inflammatory bowel disease. Antiinflammatory TGF-β plays an important role in the regulation of the expression of these mi Rs.

Involvement of heat shock proteins in gluten-sensitive enteropathy

Gluten-sensitive enteropathy,also known as coeliac disease(CD),is an autoimmune disorder occurring in genetically susceptible individuals that damages the small intestine and interferes with the absorption of other nutrients.As it is triggered by dietary gluten and related prolamins present in wheat,rye and barley,the accepted treatment for CD is a strict gluten-free diet.However,a complete exclusion of gluten-containing cereals from the diet is often difficult,and new therapeutic strategies are urgently needed.A class of proteins that have already emerged as drug targets for other autoimmune diseases are the heat shock proteins(HSPs),which are highly conserved stress-induced chaperones that protect cells against harmful extracellular factors.HSPs are expressed in several tissues,including the gastrointestinal tract,and their levels are significantly increased under stress circumstances.HSPs exert immunomodulatory effects,and also play a crucial role in the maintenance of epithelial cell structure and function,as they are responsible for adequate protein folding,influence the degradation of proteins and cell repair processes after damage,and modulate cell signalling,cell proliferation and apoptosis.The present review discusses the involvement of HSPs in the pathophysiology of CD.Furthermore,HSPs may represent a useful therapeutic target for the treatment of CD due to the cytoprotective,immunomodulatory,and anti-apoptotic effects in the intestinal mucosal barrier.