Olsalazine in active ulcerative colitis.

Olsalazine (azodisalicylate) is a new drug in which two molecules of 5-aminosalicylic acid are linked by an azo bond. Its role in the treatment of mildly active, distal ulcerative colitis was investigated. Sixty patients were randomly allocated to receive olsalazine 1 g or a placebo as a retention enema nightly for two weeks. Clinical improvement was seen in 19 (66%) and sigmoidoscopic improvement in 17 (59%) of the 29 patients receiving olsalazine compared with 12 (43%) and 11 (39%), respectively, of the 28 in the control group. These differences were not significant. In a second trial 40 patients were randomised to receive oral olsalazine 2 g daily or a placebo capsule for two weeks. Significant clinical and sigmoidoscopic improvement was seen in the patients receiving oral olsalazine compared with the patients receiving placebo capsules. Oral olsalazine may be valuable in the treatment of mildly active ulcerative colitis. Its role in maintaining remission is yet to be determined.     

Benoxaprofen in the treatment of active ulcerative colitis

We have conducted an open pilot trial to assess the therapeutic effect of the lipoxygenase inhibitor, benoxaprofen, in 10 patients with active ulcerative proctocolitis. After 18 days treatment with benoxaprofen (600 mg daily) there was no significant change in bowel habit, rectal bleeding, constitutional upset, sigmoidoscopic appearance, mucosal histology, haemoglobin, ESR, serum albumin or serumorosomucoid. Benoxaprofen itself seems unlikely to prove useful in ulcerative colitis, but evaluation of the therapeutic potential of other lipoxygenase inhibitors in inflammatory bowel disease may be worthwhile.     

Paradoxical decrease of mitochondrial DNA deletions in epithelial cells of active ulcerative colitis patients

Ulcerative colitis (UC) is a condition characterized by chronic inflammation targeted at the epithelial layer. In addition to being involved in immune phenomena, UC epithelial cells exhibit decreased oxidation of butyrate, downregulation of oxidative pathway regulatory genes, and overexpression of mitochondrial (mt) genes. We investigated whether these events, which translate an altered energy metabolism, are associated with an abnormal pattern of mtDNA deletions. Highly purified colonocytes were isolated from surgically resected control, involved and uninvolved inflammatory bowel disease mucosa. The frequency, type, and number of mtDNA deletions were assessed by PCR amplification, Southern blot analysis, and cloning and sequencing of amplified DNA fragments. The 4977 mtDNA deletion was less frequent in UC than control and Crohn's disease (CD) epithelium, regardless of patient age. Several other deletions were detected, but all were less common in UC than control and CD cells. The frequency, variety, and number of mtDNA deletions were invariably lower in colonocytes isolated from inflamed mucosa than in autologous cells from noninflamed mucosa. In conclusion, in the absence of inflammation, UC colonocytes exhibit an mtDNA deletion pattern similar to that of control cells, indicating a normal response to physiological levels of oxidative stress. In active inflammation, when oxidative stress increases, the frequency, variety, and number of mtDNA deletions decrease. Because comparable abnormalities are absent in active CD, the mtDNA deletion pattern of active UC suggests that colonocytes respond uniquely to inflammation-associated stress in this condition.     

Mast cells in ulcerative colitis

The changes in the number and ultrastruture of mast cells were studied in 37 colonoscopical biopsies from patients with ulcerative colitis. Changes in the active stage of the disease and during remission were compared. Cell counts were performed on semithin sections stained with Giemsa after osmium tetroxide fixation. This method overcome the uncertain staining found after formalin fixation. Accumulation of mast cells accompanied by intense degranulation was found to be significant in the active stage of the disease. Two forms of degranulation were observed: discharge of the individual granules and protrusion and detachment of the cytoplasmic processes containing granules. The latter was a sign of rapid degranulation, as described earlier in animal experiments. Mast cells were closely associated with capillary blood vessels, Schwann cells, neural fibres, myofibroblasts and collagenous fibres, and were also present between epithelial cells. It is assumed that close topographic contact may also imply a functional correlation.     

Comparative composition of bacteria in the human intestinal microflora during remission and active ulcerative colitis

Ulcerative colitis is a severe, relapsing and remitting disease of the human large intestine characterised by inflammation of the mucosa and submucosa. The main site of disease is the sigmoid/rectal region of the large bowel but the aetiology remains unknown. There is considerable evidence to indicate that the components of the resident colonic microflora can play an important role in initiation of the disease. The present study was aimed at characterising the faecal microflora of ulcerative colitis patients in remission and active phases to determine profile differences. Faecal samples were obtained from 12 patients, 6 with active colitis and 6 in remission. The samples were analysed for populations of lactobacilli, bifidobacteria, clostridia, bacteroides, sulphate-reducing bacteria (SRB) and total bacteria using culture independent fluorescence in situ hybridisation (FISH). Lactobacillus-specific denaturing gradient gel electrophoresis (DGGE) was then performed to compare the species present. Numbers of lactobacilli were significantly lower (p<0.05) during the active phase of the disease but the other populations tested did not differ. DGGE analysis revealed that Lactobacillus salivarus, Lactobacillus manihotivorans and Pediococcus acidilactici were present in remission, but not during active inflammation. These results imply that a reduction in intestinal Lactobacillus species may be important in the initiation of ulcerative colitis.     

Oxygen radicals in ulcerative colitis.

This article reviews the pathophysiologic concept that superoxide and hydrogen peroxide, generated by activated leukocytes, together with low-molecular-weight chelate iron derived from fecal sources and from denatured hemoglobin, amplify the inflammatory response and subsequent mucosal damage in patients with active episodes of ulcerative colitis. The putative pathogenic mechanisms reviewed are as follows: (1) Dietary iron is concentrated in fecal material owing to normally limited iron absorption. (2) Mucosal bleeding, characteristic of ulcerative colitis, as well as supplemental oral iron therapy for chronic anemia, further conspire to maintain or elevate mucosal iron concentration in colitis. (3) Fenton chemistry, driven especially by leukocyte-generated superoxide and hydrogen peroxide, leads to formation of hydroxyl radicals. (4) The resultant oxidative stress leads to the extension and propagation of crypt abscesses, either through direct membrane disruption by lipid peroxidation or through generation of secondary toxic oxidants such as chloramines. (5) Chemotactic products of lipid peroxidation, including 4-hydroxynonenal, provide positive feedback to accelerate this inflammatory/oxidative process, leading to acute exacerbations of the disease. (6) Other oxidized products, such as oxidized tryptophan metabolites, created by free radical mechanisms in or near the mucosa, may act as carcinogens or tumor promotors that contribute to the exceedingly high incidence of colon carcinoma in patients suffering from chronic ulcerative colitis. In this way, self-sustaining cycles of oxidant formation may amplify flare-ups of inflammation and mucosal injury in ulcerative colitis. This concept, if proved correct by subsequent research, would provide a rationale for several novel clinical approaches to the management of ulcerative colitis, including use of SOD mimetics, iron chelators, and chain-breaking antioxidants.     

Colorectal cytology in chronic ulcerative colitis

During a period of ten years, 109 colorectal cytology specimens were obtained from 41 patients with chronic ulcerative colitis. There were 28 male and 13 female patients, whose average age was 45 years. All patients were symptomatic and had ulcerative colitis with repeated attacks of profuse diarrhea on the average for 12 years prior to their first cytologic examination. Eight cytology specimens were positive for malignant cells, 35 had atypia, 58 were negative and 8 were unsatisfactory. The malignant cells showed marked anisocytosis, pleomorphism and nuclear hyperchromasia and appeared in loosely cohesive clusters or in single forms in an inflammatory and necrotic background. Subsequent colectomy revealed invasive carcinoma in five patients and carcinoma in situ in two. Smears that were negative or showed atypia contained abundant chronic inflammatory cells. The atypical colonic epithelial cells contained prominent nuclei and formed cohesive clusters. Surgical biopsy and/or segmental resection revealed the presence of polyps, pseudopolyps, polypoid hyperplasia, mucosal atypia and crypt abscesses in patients with atypical and negative cytologic findings. It is concluded that cytologic examination of the colon can play an important role in the examination of patients with ulcerative colitis and allows for the detection of malignant transformation of the colonic mucosa.