OBJECTIVETo investigate the expression and activity of fatty acid amide hydrolase (FAAH) in the colon and its role in children with slow transit constipation (STC).

METHODSPatients were divided into constipation group (n=21) and control group (n=15). The constipation group was consistent with the diagnostic criteria for STC. Western blotting, immunohistochemistry and real-time PCR were used to examine the FAAH expression in surgical specimen of colon. The location and distribution of FAAH and cannabinoid receptor type 1 (CB1) were detected by immunofluorescence double staining. The biological activity of colon FAAH was detected by high-performance liquid chromatography.

RESULTSWestern blotting revealed that FAAH protein expression in the ascending colon, descending colon and sigmoid colon were significantly decreased in the myenteric neurons and absorption cells in the constipation group as compared with the control group (8.68+/-3.4 vs 10.47+/-3.7, 8.21+/-1.2 vs 9.95+/-6.4, 8.01+/-7.2 vs 9.79+/-3.4, all P<0.05). The same results were found by immunohistochemistry and real-time PCR. The FAAH hydrolysis activity in the ascending colon, descending colon or sigmoid colon decreased significantly in the constipation group, as compared with the control group [(0.51+/-0.23) nmol x min(-1) x mg(-1) vs (0.84+/-0.24) nmol x min(-1) x mg(-1), (0.39+/-0.25) nmol x min(-1) x mg(-1) vs (0.55+/-0.44) nmol x min(-1) x mg(-1), (0.35+/-0.37) nmol x min(-1) x mg(-1) vs (0.58+/-0.48) nmol x min(-1) x mg(-1), all P<0.05].

CONCLUSIONFAAH expression and hydrolysis activity in the colon decrease in children with STC. FAAH may play a role in the pathogenesis of slow transit constipation in Children.