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Nitric oxide is thought to play an important role in modulating the inflammatory process. Recently an increase in the inducible form of nitric oxide synthase (iNOS) has been found in the rat trinitrobenzene sulfonic acid model of experimental colitis, and inhibition of nitric oxide synthase activity resulted in an amelioration of tissue injury. The aim of our study was to evaluate in vivo intracolonic release of nitric oxide in this model of colitis. Experimental colitis was induced in male Sprague-Dawley rats by a single intracolonic administration of trinitrobenzene sulfonic acid. Nitrite levels were determined in rectal dialysates by HPLC. The tissue myeloperoxidase and iNOS and the luminal leukotriene B4 were also measured. Nitrite levels were significantly increased in rectal dialysates during colitis and correlated significantly with tissue myeloperoxidase and iNOS activity. The correlation between nitrite dialysate levels and wall iNOS activity confirms that nitrite in dialysates is produced by inflammatory cells and not by colonic bacterial flora. Determination of nitrite levels in rectal dialysates seems a valuable method to monitor colonic inflammation in rat trinitrobenzene sulfonic acid colitis.

The activation of circulating polymorphonuclear leukocytes was determined in terms of superoxide radical generation and granulocyte elastase release in untreated patients with ulcerative colitis (N = 10) and Crohn's disease (N = 9) in remission and in control subjects (N = 10). Superoxide radical generation was determined by monitoring spectrophotometrically the reduction of ferricytochrome, after stimulation of cells with phorbol myristate acetate. Plasma elastase concentration was measured by a solid-phase enzyme immunoassay technique as the complex with alpha-1-proteinase inhibitor. Superoxide formation by polymorphonuclear leukocytes from patients with ulcerative colitis and Crohn's disease was significantly lower compared with controls [median (range) nmol/min/mg protein: Crohn's disease 7.8 (7.1-9.6); ulcerative colitis 8.25 (7.4-10.3); controls 14.7 (13.6-15.8)] (P < 0.001), while no difference was found between the two groups of patients. In contrast plasma elastase levels in patients with ulcerative colitis and Crohn's disease were similar to that of controls. This defective respiratory burst of polymorphonuclear leukocytes in patients with inflammatory bowel disease in remission, in absence of an altered degranulation, could represent an important factor for the pathogenesis of these diseases.

We evaluated the efficacy, tolerance, and acceptance of a new 5-ASA colonic foam versus 5-ASA liquid enema in the short-term treatment of active ulcerative colitis in a three-week prospective, randomized, investigator-blind study, enrolling 233 patients from 12 outpatient clinics in Italy. In arm 1 of the study, 117 patients with mild attacks received 2 g of 5-ASA as foam or enema at bedtime. In arm 2, 116 patients with moderate attacks were given 4 g of 5-ASA as foam or enema at bedtime. End points were defined as complete relief of symptoms, and endoscopic and histological evidence of remission or improvement. In patients with mild relapse, 34 of 63 (54%) treated with foam were in clinical remission after only 10 days compared with 17 of 51 (31%) treated with enemas (P < 0.05). However, there was no statistically significant difference between foam (83%) and enema (74%) after three weeks. In patients with moderate relapse, a higher proportion of patients achieved complete clinical remission in the foam group (63%) compared with enema group (52%) after three weeks (difference 11%, 95% CI -7 to 29). No significant differences were observed in endoscopic and histological evaluation of colonic mucosa between treatment groups in either arm. 5-ASA foam was well tolerated. No unexpected adverse events were reported. Patient evaluation of therapy showed that foam was much better accepted than enema because foam was more comfortable, more practical, easier to retain, and interfered less with daily living.(ABSTRACT TRUNCATED AT 250 WORDS)

Rectal treatment with enemas, foams, and suppositories is the most efficient method of delivering an adequate quantity of locally active drugs to the distal colon. In a pilot study carried out by colonoscopy in four patients, it was observed that 4 g 5-ASA in 20 ml foam spread up or beyond the splenic flexure and more extensively than 2 g 5-ASA in 10 ml foam. Therefore we have undertaken a study in order to compare by scintigraphy the colonic distribution of 4 g 5-ASA foam versus 4 g 5-ASA in 100 ml liquid enemas in 10 patients with ulcerative colitis using a crossover randomized design. Both preparations were labeled with 100 MBq [99mTc]sulfur colloid before administration. Anterior scans were taken at intervals for 4 hr. Activity, expressed as a percentage of total radioactivity, was measured in the rectum, sigmoid, descending, transverse, and ascending colon. Six patients had the same extent of spread with the two formulations; in three patients with foam and in one patient with enema a greater spread was observed. The foam reached the upper limit of disease in all cases, while enema failed in two cases. The maximum spread with foam was observed within 30 min in nine of 10 patients compared with seven of 10 after enema. Compared to enema, foam distributes more uniformly and seems to persist longer in the descending and sigmoid colon. The 5-ASA colonic foam shows some more favorable characteristics than enema for the local treatment of left-sided ulcerative colitis.

Treatment of Crohn's disease (CD) in clinical remission is still a debated issue. Previous studies have shown a high risk of relapse for patients with CD in clinical remission (CDAI less than 150) but with some abnormally high laboratory parameters as well as a possible beneficial role of low-dosage steroid treatment in this group of patients. Furthermore, good results have been reported on the efficacy of 5-aminosalicylic acid (5-ASA) in moderately active CD. In our study we verified the efficacy of a slow-release oral 5-ASA preparation in preventing relapses in a group of patients in clinical remission but with raised laboratory parameters. Forty-four patients were randomized in a double-blind manner to receive either 5-ASA (2 g/day) or placebo for four months. Location of disease and previous steroid treatment were similar in both groups. One patient in the 5-ASA group discontinued the drug because of uterine bleeding. During the study period, 13 of 22 placebo-treated patients and 11 of 21 5-ASA-treated patients relapsed (corrected chi square = NS). Considering the location of disease, three of 10 patients in the 5-ASA group and six of nine patients in the placebo group with ileal CD relapsed (therapeutic gain with 5-ASA: 36.6%; 95% allowance for error from -6% to 79.2%). Moreover, in seven patients with ileal CD who remained in remission, we found a statistically significant decrease in alpha 1 acid glycoprotein and C-reactive protein from the second month of the study.(ABSTRACT TRUNCATED AT 250 WORDS)