Intestinal alkaline phosphatase in the colonic mucosa of children with inflammatory bowel disease.
OBJECTIVE
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 obtained both 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 non-inflamed 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.


CONCLUSIONS
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.
First Department of Pediatrics, Semmelweis University, H-1083 Budapest, Hungary.
Kriszta
K
Molnár
Adám
A
Vannay
Beáta
B
Szebeni
Nóra Fanni
NF
Bánki
Erna
E
Sziksz
Aron
A
Cseh
Hajnalka
H
Győrffy
Péter László
PL
Lakatos
Mária
M
Papp
András
A
Arató
Gábor
G
Veres
D000293:Adolescent; D000367:Age Factors; D000469:Alkaline Phosphatase / Q000032:analysis* / Q000235:genetics; D001706:Biopsy; D015153:Blotting, Western; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003092:Colitis / Q000201:enzymology* / Q000235:genetics; D003106:Colon / Q000201:enzymology*; D003424:Crohn Disease / Q000201:enzymology* / Q000235:genetics; D015536:Down-Regulation; D005260:Female; D005455:Fluorescent Antibody Technique; D058851:GPI-Linked Proteins / Q000032:analysis / Q000235:genetics; D006801:Humans; D006814:Hungary; D007223:Infant; D007413:Intestinal Mucosa / Q000201:enzymology*; D008297:Male; D012333:RNA, Messenger / Q000032:analysis; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051197:Toll-Like Receptor 4 / Q000032:analysis
D058851:GPI-Linked Proteins; D012333:RNA, Messenger; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; C063088:ALPI protein, human; D000469:Alkaline Phosphatase