title: Plasma and rectal adenosine in inflammatory bowel disease: effect of methotrexate.
abstract: In animal models, the antiinflammatory mechanism of action of methotrexate has been attributed to elevation of the extracellular concentration of the endogenous autocoid, adenosine. Our goal was to determine if methotrexate elevates adenosine concentrations in plasma and at the site of disease in patients with inflammatory bowel disease. In 10 patients with Crohn's disease or ulcerative colitis, rectal adenosine and plasma adenosine concentrations were measured before and immediately after a subcutaneous injection of methotrexate, 15 or 25 mg. The mean predose rectal adenosine concentration of 2.4 mumol/l was not significantly different from the postdose concentration of 2.1 mumol/l, p = 0.17, (paired two-tailed t test). Rectal adenosine concentration tended to correlate with rectal endoscopic disease activity, r = 0.59, p = 0.067 (Spearman rank order correlation). After methotrexate injection, neither the mean daily plasma adenosine concentration, nor the plasma adenosine at any individual time point, were significantly different from preinjection values. In patients with inflammatory bowel disease, an injection of methotrexate in the clinically effective dose range does not raise rectal or plasma adenosine concentrations. A role for adenosine as the mediator of the antiinflammatory action of methotrexate is not supported.
authors.affiliation: Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: L J
authors.initials: LJ
authors.lastname: Egan
authors.forename: W J
authors.initials: WJ
authors.lastname: Sandborn
authors.forename: D C
authors.initials: DC
authors.lastname: Mays
authors.forename: W J
authors.initials: WJ
authors.lastname: Tremaine
authors.forename: J J
authors.initials: JJ
authors.lastname: Lipsky
mesh_terms: D000241:Adenosine / Q000097:blood / Q000378:metabolism*; D000328:Adult; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000494:pharmacology* / Q000627:therapeutic use; D003956:Dialysis; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000188:drug therapy* / Q000378:metabolism; D008297:Male; D008727:Methotrexate / Q000494:pharmacology* / Q000627:therapeutic use; D008875:Middle Aged; D012007:Rectum / Q000378:metabolism; D018709:Statistics, Nonparametric
chemical_list: D000893:Anti-Inflammatory Agents; D000241:Adenosine; D008727:Methotrexate