Prevention of post-operative recurrence of Crohn's disease requires adequate mucosal concentration of mesalazine

Background: Surgical resection of Crohn's disease is followed by early recu rrence in a high percentage of patients, Mesalazine has been shown to be ef fective in the prevention of post-operative recurrence, but some 50% of pat ients under treatment recur at 3 years of follow-up, Aim: To establish whether the mucosal concentration of mesalazine might aff ect the development of post-operative recurrence. Methods: Colon-ileoscopy was performed in 25 consecutive patients resected for Crohn's disease. The mean time from surgery was 14 months. After the op eration, all patients were taking oral mesalazine (Asacol, 2.4 g/day), Ten patients showed signs of endoscopic recurrence (apthae, ulcers, narrowing o f the lumen) in the neoterminal ileum, five of whom also showed juxta-anast omotic colonic involvement. Fifteen patients were free of recurrence. At en doscopy, four biopsies were taken from the perianastomotic area (two specim ens at the ileal site and two specimens at the colonic site of the anastomo sis), The specimens were weighed and immediately frozen at -80 degrees C. M esalazine concentration (ng/mg) was measured in tissue homogenates by highp erformance liquid chromatography with elcctrochemical detection. Fisher's e xact test was used for the statistical analysis, Results: The mean value of mucosal mesalazine concentration, expressed as n g/mg of tissue, was significantly lower in patients with recurrence than in those without recurrence both in the ileum (mean +/- s.d.: 21.6 +/- 28.3 v s. 70.9 +/- 47.4: P = 0.007) and in the colon (25.8 +/- 26.4 vs, 60.3 +/- 3 2.5: P = 0.010), Conclusions: The mucosal conentration of mesalazine in the juxta-anastomati c area is significantly lower in patients with recurrence than in those fre e of recurrence. These data could suggest an association between mucosal me salazine concentrations and the clinical effectiveness of the drug.