Comparative trial of sodium cromoglycate enemas with prednisolone enemas in the treatment of ulcerative colitis

In vitro study of disodium cromoglicate as a novel effective hydrotrope solvent for hypericin utilisation in photodynamic therapy

Hypericin (HY) is a naphthodianthrone that naturally occurs in Hypericum perforatum L. It is a promising photosensitiser used in photodynamic therapy for and diagnosis of oncological diseases. However, its hydrophobic character is an obstacle that has prevented its efficient use. The commonly used solvent, dimethyl sulfoxide (DMSO), is a controversial constituent of HY formulations and its use has been rejected by many researchers studying HY both in vitro and in vivo. In this study, we propose the utilisation of hydrotropy to solubilise HY in an aqueous environment. Cromolyn (DSCG) is a non-toxic, well-tolerated, antiallergic drug that has been employed in clinical practice since 1970, and in aqueous solution it acts as a hydrotrope. At a molecular ratio of 1:12,000 HY to DSCG, the compound is able to solubilise HY in aqueous environment. In an HT-29 cell suspension, DSCG (1.8 mmol L-1) considerably enhances the interaction between HY (150 nmol L-1) and HT-29 cells, which leads to an HY fluorescence emission increase with a half-time approximately 2 min compared to 29 min for samples that lack DSCG. Studies using HT-29 adenocarcinoma cells showed that DSCG at a given concentration significantly improved accumulation of HY within cells compared to DMSO (p < 0.05) despite the relative resistance of the HT-29 cell line to HY-PDT. Though no significant difference between total reactive oxygen species production was observed for photoactivated HY dissolved in DMSO and DSCG, significant singlet oxygen generation by photoactivated HY dissolved in a DSCG-containing water solution at the studied molecular ratio was confirmed. We also clarified that DSCG does not act as a scavenger of ABTS and galvinoxyl free radicals. The results from an MTT assay showed that DSCG also significantly enhanced the cytotoxicity of photoactivated HY compared to DMSO (p < 0.05). This study has demonstrated the ability of DSCG to act as a solvent of HY and enhance the effectiveness of HY-PDT compared to the commonly used organic solvent, DMSO.

Anti-allergic cromones inhibit histamine and eicosanoid release from activated human and murine mast cells by releasing Annexin A1

Background and Purpose

Although the ‘cromones’ (di-sodium cromoglycate and sodium nedocromil) are used to treat allergy and asthma, their ‘mast cell stabilising’ mechanism of pharmacological action has never been convincingly explained. Here, we investigate the hypothesis that these drugs act by stimulating the release of the anti-inflammatory protein Annexin-A1 (Anx-A1) from mast cells.

Experimental approach

We used biochemical and immuno-neutralisation techniques to investigate the mechanism by which cromones suppress histamine and eicosanoid release from cord-derived human mast cells (CDMCs) or murine bone marrow-derived mast cells (BMDMCs) from wild type and Anx-A1 null mice.

Key results

CDMCs activated by IgE-FcRε1 crosslinking, released histamine and prostaglandin (PG) D₂, which were inhibited (30–65%) by 5 min pre-treatment with cromoglycate (10 nM) or nedocromil (10 nM), as well as dexamethasone (2 nM) and human recombinant Anx-A1 (1–10 nM). In CDMCs cromones potentiated (2–5 fold) protein kinase C (PKC) phosphorylation and Anx-A1 phosphorylation and secretion (3–5 fold). Incubation of CDMCs with a neutralising anti-Anx-A1 monoclonal antibody reversed the cromone inhibitory effect.

Nedocromil (10 nM) also inhibited (40–60%) the release of mediators from murine bone marrow derived-mast cells from wild type mice activated by compound 48/80 and IgE-FcRε1 cross-linking, but were inactive in such cells when these were prepared from Anx-A1 null mice or when the neutralising anti-Anx-A1 antibody was present.

Conclusions and Implications

We conclude that stimulation of phosphorylation and secretion of Anx-A1 is an important component of inhibitory cromone actions on mast cells, which could explain their acute pharmacological actions in allergy. These findings also highlight a new pathway for reducing mediator release from these cells.

Sodium cromoglycate in the management of chronic or recurrent enterocolitis in patients with Hirschsprung's disease

BACKGROUND/PURPOSE

Chronic or recurring enterocolitis is a rare but perplexing complication of Hirschsprung's disease affecting especially patients with altered immune defense such as those with Down's syndrome. Sodium cromoglycate (SCG) is a nonabsorbable mast cell stabilizing agent that has been documented to be effective in the treatment of inflammatory bowel disease. The authors studied the effect of SCG in Hirschsprung patients with refractory chronic or recurrent enterocolitis.

METHODS

Eight patients (4 with Down's syndrome, 2 with other chromosomal aberrations, 2 otherwise healthy; age range from 4 to 22 years) with chronic (5 patients) or recurrent (>6 episodes/year, 3 patients) enterocolitis received 100 to 200 mg of SCG 4 times a day depending on the age of the patient. The chronic diarrhea or recurrent bouts of enterocolitis in the patients were refractory to dietary management and enteral antibiotics. Before the treatment all patients had ileocolonoscopy, the results of which showed macroscopic and histological chronic inflammation in all cases. No neuronal abnormalities were detected in biopsy results. None of the patients had colonic dilatation or increased anorectal resting pressures suggesting outlet obstruction.

RESULTS

The follow-up of the patients ranges from 8 months to 26 months. Three of the 5 patients with chronic enterocolitis responded favorably. In these 3 patients the median number of daily bowel movements decreased from 6 to 3, and none experienced bouts of abdominal distension. Diarrhea-related soiling decreased also significantly. Two of the 3 patients with recurrent enterocolitis have remained asymptomatic, and none has required antibiotics after the onset of SCG treatment; one patient had an episode of enterocolitis after 12 months treatment. Two patients with chronic enterocolitis did not respond to SCG. No side effects of SCG were encountered.

CONCLUSIONS

This preliminary and nonrandomized study suggests that SCG is an effective treatment modality for chronic or recurrent enterocolitis in patients with Hirschsprung's disease. Because SCG is not absorbed From the intestinal tract there are no systemic side effects.

Rectal corticosteroids versus alternative treatments in ulcerative colitis: a meta-analysis

BACKGROUND

Clear strategies to optimise the use of corticosteroids in ulcerative colitis are lacking.

AIM

A meta-analysis was undertaken to examine critically the role of rectal corticosteroids in the management of active distal ulcerative colitis.

METHODS

All reported randomised controlled trials were retrieved by searching the Medline and EMBASE databases and the bibliographies of relevant studies. Trials which met inclusion criteria were assessed for scientific rigour. Data were extracted by two independent observers according to predetermined criteria.

RESULTS

Of 83 trials retrieved, 33 met inclusion criteria. Pooled odds ratios (POR) showed conventional rectal corticosteroids and rectal budesonide to be clearly superior to placebo. In seven trials, rectal 5-aminosalicylic acid (5-ASA) was significantly better than conventional rectal corticosteroids for inducing remission of symptoms, endoscopy, and histology with POR of 2.42 (95% confidence interval (CI) 1.72-3.41), 1.89 (95% CI 1.29-2.76), and 2.03 (95% CI 1.28-3.20), respectively. Rectal budesonide was of comparable efficacy to conventional corticosteroids but produced less endogenous cortisol suppression. Side effects, although inconsistently reported, were generally minor. A cost comparison of rectal preparations showed 5-ASA to be less expensive than corticosteroids.

CONCLUSIONS

Rectal 5-ASA is superior to rectal corticosteroids in the management of distal ulcerative colitis.

Innovations in topical therapy

Topical therapy can be considered the standard treatment for distal ulcerative colitis. The group of drugs of first choice are the aminosalicylates which are effective in inducing remission in acute disease as well as in preventing relapse. Corticosteroids appear to be slightly less effective and have no proven benefit in maintenance therapy. With new topical steroids, such as budesonide, systemic effects can be minimized. The major role of corticosteroids is to complement aminosalicylates, when necessary. The new topical compounds appear to be especially valuable when there is a long-term requirement for corticosteroids. With the vast majority of patients obtaining remission with standard treatment, it is difficult to make the case for alternative substances. Short-chain fatty acids, local anaesthetics and bismuth compounds seem to be the most promising innovations in topical therapy although their equivalence or even superiority to mesalazine has not been established.

Inhibitory effects of azelastine and tranilast on leukotriene B4 and leukotriene C4 generation by rat colonic mucosa

Anti-allergic drugs such as sodium cromoglycate are known to be effective for the treatment of ulcerative colitis (UC). Because leukotriene (LT) production is considered to play an important role in the pathophysiology of UC, we examined the effect of the anti-allergic drugs, azelastine and tranilast, and the 5-lipoxygenase inhibitor, AA861, on LTB4 and LTC4 production by isolated rat colonic mucosa treated with the calcium ionophore, A23187. Preincubation of colonic mucosa with AA861 (10(-4) M) or azelastine (10(-4) M) significantly reduced AA23187-induced LTB4 (p < 0.01 and p < 0.05, respectively) and LTC4 (p < 0.01) production. Pretreatment with tranilast (10(-3) M) also significantly reduced A23187-induced LTC4 production (p < 0.05). These findings suggest that azelastine and tranilast can inhibit LT production in colonic mucosa and may be beneficial in the treatment of patients with UC.

Evidence for mast cell, leukotriene and nitric oxide involvement in the regulation of the adrenoceptor number of inflamed small intestine in guinea pigs

Changes in the populations of neurotransmitter receptors involved in the control of intestinal smooth muscle function have been associated with the altered motility of the inflamed gut. Thus, trinitrobenzenesulphonic acid (TNBS)-induced gut inflammation is accompanied by an increase in alpha- and a decrease in beta-adrenoceptor numbers in guinea pig small intestine. In the present study, we investigated the effects of anti-inflammatory compounds (cyclooxygenase inhibitor indomethacin, lipooxygenase inhibitor MK-886, nitric oxide synthase inhibitor NG-nitro-L-arginine methylester (L-NAME), mast cell stabilizer doxantrazole) on TNBS-induced adrenoceptor changes. Smooth muscle adrenoceptor populations, labelled by subtype-specific radioligands 6 days after TNBS, were significantly different from those of sham-treated controls: alpha 1- and alpha 2-adrenoceptor numbers increased by more than 50%, while beta-adrenoceptor numbers decreased by more than 50%. These changes, associated with severe inflammation as assessed histologically and by myeloperoxidase assay, were prevented by doxantrazole or L-NAME, and only partly by MK-886. In contrast, indomethacin did not prevent these changes. It appears then that: (a) mast cell mediators, nitric oxide and leukotrienes are likely to contribute to TNBS-induced changes in adrenoceptor populations in the guinea pig inflamed intestine; (b) there is no evidence for prostanoid involvement in this process. It was suggested that changes in smooth muscle adrenoceptor populations may be an important mechanism by which gut inflammation alters intestinal motility.

Effect of drugs on colonic eicosanoid accumulation in active ulcerative colitis

The effect of immunosuppressive drugs, 4-aminosalicylic acid (4-ASA), acetyl 5-aminosalicylic acid (5-ASA), and ketotifen on human colonic eicosanoid accumulation was evaluated in view of enhanced accumulation in patients with active ulcerative colitis. Azathioprine (100 micrograms/ml), cyclosporin (100 micrograms/ml), and methotrexate (100 micrograms/ml) significantly inhibited, by 25-35%, prostaglandin E2 (PGE2) accumulation by organ-cultured colonic mucosa of ulcerative colitis patients. Methotrexate was the only immunosuppressive drug that inhibited leukotriene B4 (LTB4) accumulation (50%), whereas azathioprine inhibited the accumulation of leukotriene C4 (LTC4) (25%). 5-ASA and its metabolite, acetyl 5-ASA, inhibited by 20-70% PGE2, LTB4, and LTC4 accumulation in the culture, supporting the contention that acetyl 5-ASA is as active as 5-ASA in these respects. 4-ASA had no effect on any of the eicosanoids. Ketotifen, a mast cell stabilizer, significantly inhibited the accumulation of PGE2, LTB4, and LTC4 by 33-60%. These results suggest a potential, new, unrecognized mode by which the immunomodulators induce part of their therapeutic effects in inflammatory bowel disease and support the contention that acetyl 5-ASA is as active as 5-ASA. The results obtained also indicate that ketotifen, used effectively in the prevention of bronchial asthma, inhibits the accumulation of colonic eicosanoids and, thus, may be of value in the treatment of inflammatory bowel disease.

Gastrointestinal food hypersensitivity: basic mechanisms of pathophysiology

Gastrointestinal symptoms occur in a large number of patients with food allergies. Immediate hypersensitivity mechanisms may give rise to the nausea, vomiting, abdominal pain, and diarrhea experienced by these patients. However, there are limited human data about the pathophysiological basis for these symptoms. Most of the available information comes from a variety of animal models. This article reviews the literature using models of intestinal food hypersensitivity, as well as human studies, that have contributed to our understanding of the pathophysiological mechanisms in gastrointestinal food hypersensitivity.

New developments in the pharmacotherapy of inflammatory bowel disease

In this article the clinical features and aetiology of inflammatory bowel diseases are described and current pharmacotherapeutic possibilities are explored. Also reviewed are recent developments and future prospects for the pharmacotherapy of inflammatory bowel diseases, including aminosalicylates, corticosteroids, immunosuppressants, lipoxygenase inhibitors, fish oil, sucralfate, bismuth compounds, free radical scavengers, (hydroxy)chloroquine, sodium cromoglycate and methotrexate.

New therapeutic agents in the treatment of inflammatory bowel disease

Despite intense investigation, the etiology of inflammatory bowel disease (IBD) remains unknown. Recent studies with new therapeutic agents provide insight into the pathogenesis of IBD through analysis of the clinical response to pharmacologic agents whose mechanism of action is understood. Until new agents are established, IBD will be treated with conventional drugs directed toward modifying the inflammatory responses responsible for gastrointestinal mucosal damage. Sulfasalazine, mesalamine (5-aminosalicylic acid), and corticosteroids will continue to be the mainstay of therapy for the foreseeable future. Antibiotics such as metronidazole and immunosuppressants such as 6-mercaptopurine and methotrexate are useful in Crohn's disease and ulcerative colitis in selected cases. Many new exciting agents are being investigated and show encouraging results in the treatment of IBD. This article reviews the agents used in IBD with an emphasis on new therapeutic agents.

Inflammatory bowel disease: medical therapy revisited

The chronic or recurrent immunologic and inflammatory response in ulcerative colitis and Crohn's disease may be initiated from the gut lumen. Deviation of gut contents away from the inflamed area, bowel rest, or the use of liquid diets appears to benefit Crohn's disease. The relative effects of complete bowel rest, or an elemental, hydrolysed, or polymeric liquid diet have not yet been established. Measures to alter the lumenal bacterial flora, including antibiotics, require further study. The use of corticosteroid drugs can be improved by the use of poorly absorbed or rapidly metabolized compounds. Amino-salicylates are effective in ulcerative colitis but require further study in Crohn's disease. Immunosuppressive drugs are valuable not only for a steroid sparing effect but also for control of chronic inflammation. New treatments designed to reduce inflammation are promising but will need to have high potency and an effect at the earliest stages of inflammation before a large number of different inflammatory mediators are released.

Free radicals and other reactive oxygen metabolites in inflammatory bowel disease: cause, consequence or epiphenomenon?

Oxygen-derived free radicals and other reactive oxygen metabolites have emerged as a common pathway of tissue injury in a wide variety of otherwise disparate disease processes. This has given rise to the hope that efforts directed towards the pharmacologic control of free radical-mediated tissue injury (Reilly, P.M., Schiller, H. J. and Bulkley, G. B. (1991) Pharmacologic approach to tissue injury mediated by free radicals and other reactive oxygen metabolites. Am. J. Surg. 161: 488-503) may have particular application to patients suffering from Crohn's disease and/or ulcerative colitis. However, because tissue injury by any mechanism, even direct mechanical trauma, can elicit an inflammatory response which entails the secondary generation of toxic oxidants by neutrophils and tissue macrophages, it is important that the evidence for this association be examined critically, so as to discriminate the possibility of an etiologic role for these toxic compounds from their presence as a reflection of injury caused primarily by other agents. Similarly, in considering the therapeutic potential of free radical ablation for the treatment of patients with IBD it is important to distinguish between interventions that might specifically block the fundamental injury mechanism from those which would act in a more nonspecific, anti-inflammatory role.

Newer pharmacologic agents for the therapy of inflammatory bowel disease

Topical 5-ASA Agents. Observations that 5-ASA may be the clinically active component of sulfasalazine have stimulated extensive pharmaceutical efforts to develop a new class of agents for the treatment of the inflammatory bowel diseases. Both oral and rectal forms of 5-ASA have been designed, tested, and released for use in Europe and Canada. Only one rectal 5-ASA formulation is now commercially available in the United States. Studies with topical 5-ASA have demonstrated that this formulation is safe and effective for distal colitis, even in patients with disease refractory to standard therapy. Adverse effects of topical 5-ASA are minimal. However, optimal treatment doses have not been defined, relapse is common after withdrawal of therapy, and issues regarding maintenance regimens are not yet resolved. Other disadvantages include the expense and inconvenience of enema therapy. However, rectally administered 5-ASA is an appropriate initial therapy for the treatment of distal ulcerative colitis, or as a therapeutic option for refractory distal colitis. Data are insufficient to make recommendations regarding the use of topical 5-ASA in Crohn's disease. Whether this class of agents will be of benefit for Crohn's proctitis or for perineal disease must await further clinical trials. Oral 5-ASA Agents. There appears to be a well-substantiated benefit equivalent to that of sulfasalazine achieved by the new oral formulations of 5-ASA when used for the treatment of acute mild to moderate ulcerative colitis, and as maintenance treatment of ulcerative colitis in remission. Adverse reactions to these agents are uncommon, usually mild, and infrequently require withdrawal of therapy. The major problem reported with these agents is watery diarrhea, most commonly associated with olsalazine, but the practical importance of this adverse effect is disputed. Rare occurrences of reversible pericarditis and acute pancreatitis have been encountered during clinical application of these agents. As more experience is obtained, these agents may become the initial therapy of choice for the treatment of mild to moderate ulcerative colitis and for maintenance in inactive disease. Currently available data have defined a role for these agents as an important alternative for the treatment of patients intolerant or allergic to sulfasalazine. As with sulfasalazine, these agents should not be used as the sole treatment for severely active ulcerative colitis. Many unanswered questions remain regarding therapy with these agents for ulcerative colitis. Still undefined are optimal drug dosages, appropriate dosing intervals, and the necessary duration of therapy.(ABSTRACT TRUNCATED AT 400 WORDS)

Topical treatment of ulcerative colitis

It is clear that the therapeutic options available for the treatment of ulcerative proctosigmoiditis have increased over the last few years and in the future additional therapies will be available. Therapy will have to be individualized. Studies to date have generally failed to confirm the superiority of one form of treatment over another, although there is some evidence that high-dose 5-ASA enemas are superior to hydrocortisone enemas. Patients who fail to respond to one form of therapy may respond to another therapeutic modality. Continued evaluation of topical therapies provides not only an opportunity to improve the treatment prospects for patients but also allows for examination of potential mechanisms of action of therapeutically active compounds. Future research directions should also include assessment of combination therapy, the more widespread use of suppositories, and strategies to encourage patient compliance. Larger multicenter trials are needed to assess the effectiveness of some of the newer compounds. The role of topical therapy for patients with Crohn's disease confined to the left colon requires evaluation.

Inflammatory bowel disease

An increasing number of options are available for the treatment of inflammatory bowel disease; the selection depends on the extent and severity of the disease. Experience with sulfasalazine and corticosteroids has led to a proliferation of 5-aminosalicylic acid (5-ASA) compounds and experimentation with alternative corticosteroid preparations. Given rectally 5-ASA is particularly effective in the treatment of distal ulcerative colitis, and experience is accumulating with several oral formulations. Metronidazole is useful in some cases, and immunosuppressive agents have a role in some patients with chronic refractory disease. A variety of measures, such as nutritional therapy, surgery and psychosocial support, are important elements of therapy. Further therapeutic innovations are expected as the etiology and pathogenesis are clarified.