Effect of nicotine on rectal mucus and mucosal eicosanoids

Pilot trial of nicotine patches as an alternative to corticosteroids in ulcerative colitis

In ten patients with mild to moderate clinical relapses of ulcerative colitis during treatment with mesalazine (1 g t.i.d.) and with a previous history of poorly tolerated steroid courses, transdermal nicotine (15 mg daily) was added for 4 weeks. Clinical findings were assessed by employing Rachmilewitz's activity index. In 7 of the patients, clinical remission was achieved, the results persisting for up to 3 months after nicotine withdrawal. Endoscopic and histological examination, when performed, confirmed the clinical findings. Nicotine patches may represent a good alternative to steroids in selected patients with mild to moderate relapses of ulcerative colitis. The precise mechanism of action remains unknown.

Intracolonic administration of zileuton, a selective 5-lipoxygenase inhibitor, accelerates healing in a rat model of chronic colitis

BACKGROUND

5-Lipoxygenase products play a part in inflammatory response.

AIMS

The effect of intracolonic administration of zileuton (a 5-lipoxygenase inhibitor) on colonic damage and eicosanoid local release was assessed in a rat model of colitis.

METHODS

Ninety rats with trinitrobenzenesulphonic acid induced colitis were randomised to receive placebo, 5-aminosalicylic acid (50 mg/kg), or zileuton (50 mg/kg) intracolonically for four weeks. Local eicosanoid release was monitored by intracolonic dialysis throughout the study. The colon was removed for macroscopic and histological assessment at weeks 1, 2, and 4 after colitis induction in 10 rats of each group.

RESULTS

Zileuton significantly reduced macroscopic damage score after four weeks of treatment in comparison with the other two groups (p = 0.034). In addition, zileuton administration significantly increased the intracolonic release of both thromboxane B2 at week 1 (p = 0.05) and prostaglandin E2 at weeks 2 and 4 (p < 0.05). Zileuton and 5-aminosalicylic acid decreased leukotriene B4 release by 90% at day 3.

CONCLUSIONS

Intracolonic zileuton, compared with 5-aminosalicylic acid and placebo, seems to improve the course of the disease in a model of chronic colitis. This effect may be related to an increased and maintained production of prostaglandin E2 together with inhibition of leukotriene B4 synthesis.

Colonic mucus, smoking and ulcerative colitis

Human colonic mucosal protection is not fully understood but may in part rely on a layer of mucus gel adherent to the mucosa. Ulcerative colitis may occur if mucosal protection breaks down. Two studies are presented, both of which relate to the aetiology of ulcerative colitis. First, a layer of adherent mucus gel was demonstrated by a simple, reliable method. Measurements of mucus layer thickness were made in freshly resected colonic specimens and shown to increase from a mean of 107 microns on the right colon to 155 microns in the rectum. In ulcerative colitis the layer is significantly thinner or absent, whereas in Crohn's disease the colonic mucus layer is significantly thicker. Second, the relationship between smoking and colitis is explored by a double-blind, randomised and placebo-controlled trial of transdermal nicotine in active disease. Significant clinical benefit was seen, indicating nicotine may be both useful therapeutically and the component of tobacco smoke that acts to protect against colitis. Since smoking and nicotine have actions on mucosae and mucus in other organs, it is argued that there is a mucus deficiency in ulcerative colitis that smoking acts to reverse.

Absence of effect of nicotine on rectal sensation, rectal compliance, and anal sphincter pressures in healthy subjects

We examined the effect of nicotine on rectal sensation, rectal compliance, and anorectal sphincter function in healthy volunteers. Eleven healthy (ex-smoker) subjects were randomized in a double-blind, crossover, placebo-controlled study of 12 mg nicotine-containing chewing gum. All treatment periods (nicotine or placebo chewing gum) were preceded by a control period without chewing gum. Crossover study was done after a washout period of more than seven days. The following measurements were made: highest anorectal sphincter tone, highest anorectal sphincter squeeze tone, percentage relaxation of the anorectal sphincter with rectal balloon distension, threshold of rectal sensation, maximal tolerable volume of air inflation of a rectal balloon, and rectal compliance. There was no significant difference in the two control periods. Chewing placebo gum had no significant effect on any of the measurements when compared with control. Compared with placebo, nicotine did not significantly affect on any of the measurements. We conclude that neither nicotine nor the sham-feeding effect of chewing placebo gum appear to have any effect on anorectal sensorimotor function or on rectal compliance in healthy ex-smokers.

Ulcerative colitis responsive to smoking and to nicotine chewing gum in a patient with alpha 1 anti-trypsin deficiency

Ulcerative colitis is one of the few diseases in which smoking appears to confer some benefit (1). We report a patient whose ulcerative colitis deteriorated on several occasions on stopping cigarettes, and improved on restarting smoking. As a result, she continued smoking despite developing airflow limitation and severe emphysema. She was subsequently found to have alpha 1 anti-trypsin deficiency. She later noticed that she could get a similar benefit in her colitis with nicotine chewing gum as she had with cigarettes. For patients with smoking-responsive ulcerative colitis, non-tobacco forms of nicotine delivery such as gum or transdermal patches should be considered to avoid the hazards of cigarette smoke.

Nicotine inhibits cytokine synthesis by mouse colonic mucosa

We examined the in vivo effect of nicotine on the synthesis of (pro)inflammatory mediators by mouse colonic mucosa. The synthesis of lipid mediators such as the prostanoids prostaglandin E2, 6-keto-prostaglandin F1 alpha and thromboxane B2, the 5-lipoxygenase products leukotriene B4 and leukotriene C4 and the platelet activating factor was not affected, whereas the synthesis of the pro-inflammatory cytokines interleukin-1 beta and tumor necrosis factor alpha was completely abolished. The beneficial effects of smoking and nicotine in ulcerative colitis could be attributed to this inhibition.

Transdermal nicotine for active ulcerative colitis

BACKGROUND

Ulcerative colitis is largely a disease of nonsmokers. Because anecdotal reports suggest that smoking and nicotine may improve the symptoms of the disease, we examined the effect of nicotine as a supplemental treatment for ulcerative colitis.

METHODS

We treated 72 patients with active ulcerative colitis with either transdermal nicotine patches or placebo patches for six weeks in a randomized, double-blind study. Incremental doses of nicotine were given; most patients tolerated doses of 15 to 25 mg per 24 hours. All the patients had been taking mesalamine, and 12 were receiving low doses of glucocorticoids; these medications were continued without change during the study. Clinical, sigmoidoscopic, and histologic assessments were made at base line and at the end of the study; symptoms were recorded daily on a diary card, and the clinician made a global assessment. Side effects and plasma nicotine and cotinine concentrations were monitored throughout the study.

RESULTS

Seventeen of the 35 patients in the nicotine group had complete remissions, as compared with 9 of the 37 patients in the placebo group (P = 0.03). The patients in the nicotine group had greater improvement in the global clinical grade of colitis (P < 0.001) and the histologic grade (P = 0.03), lower stool frequency (a difference of 1.6 stools daily; P = 0.008), less abdominal pain (P = 0.05), and less fecal urgency (P = 0.009). More patients in the nicotine group had side effects (23, vs. 11 in the placebo group; P = 0.002), the most common of which were nausea, lightheadedness, headache, and sleep disturbance. Withdrawals due to ineffective therapy were more common in the placebo group (3 vs. 8, P = 0.12).

CONCLUSIONS

The addition of transdermal nicotine to conventional maintenance therapy improves symptoms in patients with ulcerative colitis.