Fixed Weight Based Thiopurine Dosing Lowers Steroid Free Remission Rates in Crohn's Disease

Abstract

G A A b st ra ct s 2008;20:629). We hypothesized effectiveness of GMA and LMA might be dependent on depletion of granulocyte and monocytes. S100A12 was reported to be exclusively expressed in neutrophils and up-regulated by TNF α. The aim of this study was to investigate the changes of serum S100 A12 concentration in the GMA treatments and whether S100A12 increases the expression of adhesion molecules, CXCL and CCL chemokines. Methods; 24 patients with ulcerative colitis were treated with GMA. Serum S100A12 was estimated by ELISAmethods. Clinical activity index (CAI) and serumCRP concentrationwere also checked. Immunohistochemical staining of S100A12 and receptor for advanced glication end products (RAGE) were performed in the operated specimens of patients with ulcerative colitis and with colonic carcinoma (control). HUVEC were seeded into 12 well plates and confluent plates were used to experiments. Each experiment was performed in triplicate. HUVEC were treated with human recombinant S100A12 protein. RNA was extracted by RNeasy Mini Kit. 1.5μg RNA was reverse-transcriptated into cDNA. ICAM-1, VCAM-1, IL-8, CCL-2 (MCP1), CCL5 (RANTES), CXCL9 (IP-10) and CXCL10 (Mig) mRNA was quantitated by realtime PCR. Results; S100A12 staining was faintly recognized in the mucosal layer of normal control. S100A12 staining was increased in infiltrating cells in inflamed colon in patients with ulcerative colitis. Strong staining was also recognized in crypt abscess. RAGE staining was also faintly recognized in the epithelial cells in nornmal control. However, RAGE staining was increased in the inflamed epithelial cells. Significantly serum S100A12 concentration was positively correlated with CAI (n=34, p=0.02, rs=0.404). 16 patients were able to estimate S100A12 concentration in the points of preand post-GMA treatment. 13 patients were GMA-responders and 3 patients were non GMA-responders. Serum S100A12 concentration was significantly decreased in GMA responders (prevs postGMA, 1.34±1.08 vs 0.60±0.50, p<0.05). However, Serum S100A12 concentration of non GMAresponders was gradually increased with GMA treatments. ICAM-1, VCAM-1, IL-8, IP-10, Mig, MCP-1 and RANTES mRNA expressions were increased by S100A12 in HUVEC cell lines in time and dose-dependent manners. Conclusion; one of the mechanisms of GMA effect might be correlated with depletion of S100A12 by adsorption of activated neutrophils. S100A12 might aggravate acute and chronic inflammation by up-regulation of adhesion molecules, CXCL and CCL chemokines.