Role of oxygen-derived free radical scavengers in the management of recurrent attacks of ulcerative colitis, Part 1
Aws S. Salim
Baghdad, Iraq

Abstract

This double-blind, randomized study investigated the role of oxygen-derived free radical scavengers in the management of recurrent attacks of ulcerative colitis. To this end, allopurinol (50 mg four times a day) and dimethyl sulfoxide (500 mg four times a day) were administered orally. Patients with recurrent attacks of moderate proctosigmoidal ulcerative colitis, in spite of prophylaxis with orally administered sulfasalazine (2 gm daily), were given 10 mg prodnisolone by mouth four times a day: 500 mg sulfasolazine by mouth four times a day; and morning and evening retention steroid enema (Prodsol, 20 mg) alone or with allopurinol or dimethyl sulfoxide. After 2 weeks of treatment with sulfasalazine and prodnisolone alone, 51% of patients (n 45) were free of symptoms. Addition of allopurinol (n = 46) or dimethyl sulfoxide (n = 45) to the mentioned regimen controlled the symptoms within 2 weeks in 84% of patients (p < 0.01). During 12 months of prophylactic treatment, 5% of patients (n = 42) who were given sulfasolazine (2 gm daily) and allopurinol and 5% of patients (n = 40) who were given sulfasalazine (2 gm daily) and dimethyl sulfoxide relapsed compared with 25% of patients who were given sulfasoizine (2 gm daily) alone (p < 0.05). The results suggest that oxygen-derived free radicals may be involved in the mechanism of ulcerative colitis and that removing them may be useful in the treatment of attacks and in protecting the colon against recurrence of attacks. (J Lm Clin Med. 1992;119:710-7)

Abbreviations:

DMSO = dimethyl sulfoxide
ESR = erythrocyte sedimentation rate
WBC = white blood cell

Ulcerative colitis is a diffuse inflammation of the mucous membranes of the colon, which when severe, leads to extensive ulceration. The cause of this disease is unknown, but the possibility exists that it is a hypersensitivity reaction to an unknown antigen.1-3 The extent of ulcerative colitis can be categorized as proctitis, proctosigmoiditis, or total colitis; and its severity can be identified as mild, moderate, or severe.4, 5Oxygen-derived free radicals, such as the superoxide anion and the hydroxyl radical, are cytotoxic and promote lipid peroxidation and membrane damage by cross-linking proteins, lipids, and nucleic acids.6 The intestinal mucosa of patients with inflammatory bowel disease contains increased numbers of monocytes and macrophages, cells that produce oxidative bursts that expose the colonic mucosa to oxygen-derived free radicals.7 Since these radicals mediate tissue damage and have been recently shown to be responsible for the development of mucosal injury of the gastrointestinal tract in the rat,8-10 they may play a role in the mechanism of ulcerative colitis. The present study was therefore undertaken to test whether drugs that are capable of scavenging oxygen-derived free radicals could be useful in the treatment of and protection against recurrent attacks of ulcerative colitis.

Methods

Drugs

A 1% solution of allopurinol (Burroughs Wellcome Co., Research Triangle Park, N.C.) was prepared by dissolving the powder in double-distilled water that contained the equivalent of 0.1 mol/L NaOH. A 10% solution of DMSO (pharmaceutical grade, B.P., Sigma, St. Louis, Mo.) was prepared by diluting the stock solution with double-distilled water. Solutions were placed in 600 ml capacity dark colored glass bottles of identical appearance. Patients were issued a fresh supply of solutions every 30 days. They were also given sulfasalazine (Salazopyrin, Pharmacia Ltd., Milton Keynes, England) and prednisolone tablets (Prednesol, Glaxo Laboratories Ltd., Greenford, England) and retention enema (Predsol, Glaxo Laboratories Ltd., Greenford, England). All patients were given the same number of tablets and volumes of solution.

Study Design

This was a prospective, randomized, double-blind trial conducted in consecutive patients with recurrent attacks of moderate proctosigmoidal ulcerative colitis in spite of prophylaxis with sulfasalazine (2 gm daily). Randomization was carried out by drawing sealed envelopes. Treatment started immediately after the diagnosis was made.Patients were recruited into the study if they showed clinical signs and symptoms of the disease coupled with histologic evidence of active colitis (acute inflammation with a background of long-term nonspecific inflammatory changes). Remission or recovery from attacks indicates that the patient has become free of symptoms and has no diarrhea; sigmoidoscopy (60 cm flexible sigmoidoscope) shows no contact bleeding or deeply congested mucosa with discharge of blood, mucus, or pus; hematologic and biochemical data return to normal values; and histologic examination shows the disease to be inactive.Relapse or recurrent attacks were diagnosed on the basis of histologic evidence of active ulcerative colitis, even if it occurred without clinical signs and symptoms of the disease.A patient was judged to be suitable for this study only if there was no evidence of enteric infection, alcoholism, pregnancy, ingestion of prohibited drugs, Zollinger-Ellison syndrome, hepatic or renal disorders, malnutrition, or serious underlying diseases (e.g., cardiorespiratory problems). Specifically, other gastrointestinal disorders, such as irritable bowel syndrome, were excluded, because they would make it difficult to assess patients and the significance of signs and symptoms. Ulcerative colitis was diagnosed from patient history (medical and social history together with age, sex, and therapeutic history were recorded), physical examination, proctoscopy, and sigmoidoscopy (60 cm flexible sigmoidoscope) with biopsies. The diagnosis of ulcerative colitis in an active phase was based on microscopic observation of mucosal ulceration and acute suppurative inflammation with focal collections of neutrophils and frank abscesses in the vicinity of the crypts of Lieberkühn. The severity of colitis was determined by the methods of Edwards and Truelove11 (diarrhea: 4 to 6 times daily; blood in feces: moderate amounts; fever: less than 99.5° F (evening); tachycardia: less than 90 beats/min; anemia: not less than 75% hemoglobin; elevated ESR: less than 30 mm/hr). All of the patients were admitted to the hospital and if necessary, general medical measures were undertaken to correct any fluid and electrolyte imbalances (particularly potassium imbalances) and to treat any anemia. Standard hematologic and biochemical measurements (hemoglobin, ESR, packed cell volume. WBC count, electrolytes, determinations of urea, creatinine, urate levels, liver function tests), and urinalysis were performed. Stools were cultured for pathogenic organisms to rule out enteric infections. Radiologic examination with plain abdominal films was always performed to exclude the possibility of colonic perforation or toxic megacolon. Patients were given a low-residue and milk-free diet, which is high in protein and calories, until their attacks subsided.Progress was determined by monitoring constitutional disturbances; bowel frequency; passage of blood, mucus, or pus via the rectum; by sigmoidoscopy (this was carried out in all cases once a week over the first 4 weeks and then at 6 weeks and at 8 weeks after treatment had started; the colorectal mucosa was always biopsied after clinical recovery from the attack) and by regular checks of the hemoglobin, ESR, WBC, and serum albumin levels; the latter is a useful guide to the severity of protein-depleting enteropathy. These parameters of progress were also used to compare attacks among the groups.After recovery from the attack (criteria: see above), the extent of proximal inflammatory changes was determined by a double-contrast barium enema and colonoscopy with biopsies. Once recovery was achieved and administration of corticosteroids had been tapered off, patients automatically and without breaking the treatment code entered the maintenance part of the study in which, apart from prednisolone, they continued to receive the same trial medication as in the acute phase.These patients were followed up in the outpatient department where they were physically examined, underwent sigmoidoscopy, and had biopsies performed for any suspicious colorectal mucosa. During the first 2 years, these procedures were carried out every 3 months and thereafter once every 6 months. Colonoscopic assessment of the disease was done every 6 months, and a double-contrast barium enema was performed annually. The treatment code for this study was broken at the end of the first year of follow-up, which was the end point of the trial. All of the endoscopic procedures that were performed throughout the study were carried out by the author.The compliance of patients with their therapeutic regimens was assessed during active and prophylactic treatment by supplying them with special charts to mark their treatment and to record any adverse effects. Furthermore, at each follow-up visit the returned medication was inspected.

Ethical Considerations

This study was approved by the ethical committee on human experimentation of the hospital, and every patient gave written consent.

Table I

Suitability of patients for evaluation

 
Active Treatment
Prophylactic Treatment
Prednisolone
& sulfasalazine
Prednisolone,
sulfasalazine,
& allopurinol
Prednisolone,
sulfasalazine,
& DMSO
Sulfasalazine
Sulfasalazine
& allopurinol
Sulfasalazine
& DMSO
Total entered
51
50
52
45
46
45
Suitable for evaluation
45
46
45
40
42
40

Not suitable for evaluation because of:
Intolerance
--
--
 1
--
--
 1
Adverse events
 3
 1
 2
 1
--
--
Noncompliance
 1
 1
 2
 1
 1
 1
Deteriorated and underwent surgery
 2
 2
 2
 2
--
--
Prohibited drugs used
--
--
--
 1
 1
--
Failed to attend for follow-up
--
--
--
--
 2
 3
Total not evaluable
 6
 4
 7
 5
 4
 5

 

Study Groups

One hundred and fifty-three consecutive patients with recurrent attacks of moderate proctosigmoiditis were divided into three groups.

  1. In the first group patients were given prednisolone by mouth 10 mg four times a day, sulfasalazine by mouth, 500 mg four times a day, the vehicle solution of allopurinol by mouth, 5 ml four times a day, and corticosteroid retention enemas that contained prednisolone-21-phosphate (Predsol, 20 mg) in the morning and evening.
  2. In the second group, patients had the same regimen in addition to allopurinol by mouth, 5 ml (500 mg) four times a day.
  3. In the third group, patients were treated like the first group and in addition, received DMSO by mouth, 5 ml (500 mg) four times a day.

Patients who still had symptoms after treatment for 2 weeks or those whose conditions were deteriorating were treated with higher doses of corticosteroids. Once symptoms ceased, patients continued their respective therapeutic regimens for 1 month, and then the corticosteroids were tapered over the following 3 weeks (i.e., for the acute attack steroids were given until patients became free of symptoms and were stopped 7 weeks later). Thereafter, they were maintained on their remaining oral regimens (prophylaxis) for 1 year.

Exclusion on patients from evaluation

The decision to regard patients as not suitable for efficacy analysis was made before the treatment code was broken. Additional intention-to-treat analyses were performed and reincluded such patients with various theoretically possible outcomes to examine what influence their exclusion might have had on the conclusion reached.

Statistical analysis

Results are expressed as percentages or means ± SEM. A sample size of 135 patients with 45 in each group was initially chosen. On the basis of a two-tailed t test, such a size should detect a significant difference of 30% between therapy with and therapy without radical scavengers (p < 0.05) with a probability of 80% for the overall sample. Because of the anticipated problems of some patients, who were not suitable for evaluation, which could weaken any conclusions drawn, the aim was to enter at least 50 patients in each group. The Wilcoxon signed-rank test for paired nonparametric data was used to determine the statistical significance (p < 0.05) of observed differences within each group and the Mann-Whitney U test for nonparametric data or the X² test with Yates' correction were used for comparisons among the groups.Life-table analyses with Mantel-Cox (log rank) and Breslow-generalized Wilcoxon statistics12 were used to evaluate the statistical differences among treatments. Pairwise comparisons were made between groups with or without radical scavengers. Cox proportional hazard models were then used to investigate the effects of radical scavengers on the outcome of treatment and prophylaxis by conventional agents; other patient factors were taken into account as covariates.

Results

Patient characteristics are detailed in Tables I and II. Treatment and follow-up results are shown in Tables III and IV.

Patient Characteristics

Active Treatment: Fifty-one patients (28 women and 23 men with an age range of 18 to 63 years; mean, 32 years) were randomized to the sulfasalazine and prednisolone group. Fifty patients (27 women and 23 men with an age range of 20 to 61 years; mean, 34 years) were randomized to the allopurinol group. Fifty-two patients (28 women and 24 men with an age range of 19 to 67 years; mean, 31 years) were randomized to the DMSO group. These patients were randomized to the groups for a period of 2 years and 11  months. The patients who were excluded from evaluation are presented in Table I. The characteristics of those remaining (Table II) were similar among the three groups in terms of number, age, sex ratio, and history of colitis.

Table II

 
Active treatment
Prophylactic treatment
Prednisolone & sulfasalazine Prednisolone &sulfasalazine, & sulfasalazine Prednisolone sulfasalazine, & DMSO Sulfasalazine Sulfasalazine & allopurinol Sulfasalazine & DMSO
n 45 46 45 40 42 40
Age (yr)            
  Mean 33 33 30 34 32 31
  Range 18-63 20-57 19-64 18-63 21-57 19-61
Women (no.) 24 25 25 20 22 22
Men (no.) 21 21 20 20 20 18
Mean length of history (yr) 8.9 7.6 8.3      
Mean time since last acute attack (mo) 5.8 6.1 5.5      
Mean no. of relapses in previous 3 years 2.9 3.7 3.1      
Last treatment used for the acute attack (no.)
  Prednisolone 45 46 45      
  Sulfasalazine 45 46 45      
History of treatment of acute attacks by other than the above agents None None None      
History of maintenance of remission by other than sulfasalazine None None None      
Previous response rate to treatment of acute attacks (%) 100 100 100      

Prophylactic treatment

Forty-five patients (24 women and 21 men with an age range of 18 to 63 years; mean, 33 years) were given sulfasalazine. Forty-six patients (25 women and 21 men with an age range of 20 to 57 years; mean, 33 years were given sulfasalazine with allopurinol. Forty-five patients (25 women and 20 men with an age range of 19 to 64 years; mean, 30 years) were given sulfasalazine with DMSO. After exclusion of the patients who could not be evaluated (Table I), the characteristics of those inthe three groups were comparable in regard to age and sex ratio (Table II).

The number of patients excluded from active or prophylactic treatment was not significantly different among the groups.

 
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