title: Protease activated receptor 4 status of mast cells in post infectious irritable bowel syndrome.
abstract: BACKGROUND
  Growing evidence suggests that protease activated receptors (PARs) are mediators of persistent neuropathic pain, but their possible function as mediators in patients with post infectious irritable bowel syndrome (PI-IBS) remains to be further explored. This article aims to investigate the expression of PAR(2) and PAR(4) in the colonic mucosa of patients with PI-IBS, focusing on correlation with mast cell activation status.
  
  
  METHODS
  A total of 17 normal controls and 23 patients with PI-IBS volunteered the study. The expression and localization of PAR(2) and PAR(4) were investigated by RT-PCR and immunohistochemistry, and the expression of PAR(2) and PAR(4) in the mast cells was examined using double-immunofluorescence staining.
  
  
  RESULTS
  The immunohistochemical study revealed that epithelial and submucosal cells showed immunoreactivity for both PAR(2) and PAR(4). Protease activated receptor 4 mRNA expression and immunoreactivity were down-regulated in PI-IBS compared with the control group. Specifically, a reduced immunoreactivity for PAR(4) was observed in mast cells of PI-IBS compared with normal controls, whereas there are no significant differences shown in PAR(2) between the PI-IBS and the control group. It is also found that the PAR(4) immunoreactivity decreases, while the activity of mast cells increases in PI-IBS rather than normal controls.
  
  
  CONCLUSIONS
  This study outlines the down-regulation of PAR(4) in the mast cells of PI-IBS. It could be of considerable interests in understanding the mechanisms involved in the persistent colonic hypersensitivity and their potential role as therapeutic targets for PI-IBS.
authors.affiliation: Department of Gastroenterology, Qilu Hospital of Shandong University, Jinan, Shandong Province, China.
authors.forename: W
authors.initials: W
authors.lastname: Han
authors.forename: Z
authors.initials: Z
authors.lastname: Wang
authors.forename: X
authors.initials: X
authors.lastname: Lu
authors.forename: C
authors.initials: C
authors.lastname: Guo
mesh_terms: D000293:Adolescent; D000328:Adult; D003106:Colon / Q000378:metabolism*; D015536:Down-Regulation; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D043183:Irritable Bowel Syndrome / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008407:Mast Cells / Q000378:metabolism*; D008875:Middle Aged; D044464:Receptor, PAR-2 / Q000235:genetics / Q000378:metabolism; D018179:Receptors, Thrombin / Q000235:genetics / Q000378:metabolism*
chemical_list: D044464:Receptor, PAR-2; D018179:Receptors, Thrombin; C112908:protease-activated receptor 4