Evaluation of the Extrapineal Sources of Melatonin in Patients with Lymphocytic Colitis
Pages : 857-863, DOI: https://doi.org/10.14741/ijmcr/v.6.4.29Download PDF
Melatonin can be synthesized by different cells in the gastrointestinal tract. The aim of this study was to evaluate the expression of melatonin-synthesizing enzymes: arylalkylamine-N-acetyltransferase(AANAT) and N-acetylserotonin methyltransferase (ASMT) in colonic mucosa and urinary 6-sulfatoxymelatonin excretion(aMT6s) in patients with lymphocytic colitis(LC) related to the number of intraepithelial lymphocytes(IEL) and enterochromaffin cells (EC). The study included 32 healthy subjects (HS group) and 36 patients with lymphocytic colitis (LC group). The diagnosis was based on histological and immunohistochemical performances using mouse monoclonal antibodies (chromogranin A – LK 2H10). EC were counted in 10 fields of each bioptate at 40x magnification. The level of mRNA expression of AANAT and ASMT was estimated in colonic mucosa with RT-PCR. The urine concentration of aMT6s was determined by photometric method. Significant differences were found in obtained results between HS and LC group: the number of IEL 14.1±3.41 vs. 32.4±5.50 per 100 surface colonocytes (p< 0.001); the number of EC 32.2±10.1 vs. 70.4±21.2 (p< 0.001); AANAT -1.32±0.47 vs. 2.32±0.65 (p< 0.001; ASMT – 1.51±0.59 vs. 2.80±0.92 (p <0.001) aMT6s- 13.4±4.87 vs. 19.9±6.29 (p< 0.001). Moreover, a positive correlation was found between the number of EC and ASMT (p= 0.011) and between EC and aMT6s (p < 0.001). No correlation occurred between the number of IEL and AANAT p=0.932) and AMST (n=0.536) and aMT6s (p=9.288). These results indicate that the enterochromaffin cells in colonic mucosa are the main extrapineal source of melatonin in patients with lymphocytic colitis.
Keywords: Lymphocytic colitis, intraepithelial lymphocytes, enterochromaffin cells, melatonin synthesizing enzymes, 6-sulfatoxymelatonin