Systematic review: coxibs, non-steroidal anti-inflammatory drugs or no cyclooxygenase inhibitors in gastroenterological high-risk patients?

Selective cyclooxygenase-2 inhibitors have been marketed as alternatives of conventional, non-steroidal anti-inflammatory drugs with the purpose of reducing/eliminating the risk of ulcer complications. Unexpectedly, randomized-controlled trials revealed that long-term use of coxibs, such as rofecoxib, significantly increased the risk of myocardial infarction and stroke, while the use of valdecoxib was associated with potentially life-threatening skin reactions. Subsequently, rofecoxib and valdecoxib were withdrawn from the market. Although more strict precautions for other coxibs, such as celecoxib, etoricoxib, lumiracoxib and parecoxib, may be accepted/recommended by regulatory agencies, a critical review of published data suggests that their use may not be justified - even in high-risk patients - taking benefits, costs and risks into consideration. Clinicians should, therefore, never prescribe coxibs to patients with cardiovascular risk factors, and should only reluctantly prescribe coxibs to patients with a history of ulcer disease or dyspepsia to overcome persistent pain due to, e.g. rheumatoid arthritis or osteoarthritis. Instead, they should consider using conventional non-steroidal anti-inflammatory drugs in combination with a proton pump inhibitor or a prostaglandin analogue, especially for patients with increased cardiovascular risks, i.e. established ischaemic heart disease, cerebrovascular disease and/or peripheral arterial disease, or alternatively acetaminophen. An evidence-based algorithm for treatment of a chronic arthritis patient with one or more gastrointestinal risk factors is presented.

Expression of Toll-like receptor 9 and response to bacterial CpG oligodeoxynucleotides in human intestinal epithelium.

Recognition of repeat CpG motifs, which are common in bacterial, but not in mammalian, DNA, through Toll-like receptor (TLR)9 is an integral part of the innate immune system. As the role of TLR9 in the human gut is unknown, we determined the spectrum of TLR9 expression in normal and inflamed colon and examined how epithelial cells respond to specific TLR9 ligand stimulation. TLR9 expression was measured in human colonic mucosal biopsies, freshly isolated human colonic epithelial cells and HT-29 cells by reverse transcriptase-polymerase chain reaction or Western blotting. Colonic epithelial cell cultures were stimulated with a synthetic CpG-oligodeoxynucleotide (ODN), exhibiting strong immunostimulatory effects in B cells. Interleukin (IL)-8 secretion was determined by enzyme-linked immunosorbent assay, nuclear factor-kappaB (NF-kB) activity by electrophoretic mobility shift assay and IkB phosphorylation by Western blotting. TLR9 mRNA was equally expressed in colonic mucosa from controls (n = 6) and patients with ulcerative colitis or Crohn's disease disease (n = 13). HT-29 cells expressed TLR9 mRNA and protein and responded to CpG-ODN (P < 0.01), but not to non-CpG-ODN stimulation, by secreting IL-8, apparently in the absence of NF-kB activation. Primary epithelial cells isolated from normal human colon expressed TLR9 mRNA, but were completely unresponsive to CpG-ODN stimulation in vitro. In conclusion, differentiated human colonic epithelial cells are unresponsive to TLR9 ligand stimulation in vitro despite spontaneous TLR9 gene expression. This suggests that the human epithelium is able to avoid inappropriate immune responses to luminal bacterial products through modulation of the TLR9 pathway.

Activation of nuclear factor kappaB in colonic mucosa from patients with collagenous and ulcerative colitis.

BACKGROUND AND AIMS: Expression of inducible nitric oxide synthase (iNOS) is greatly upregulated in the colonic mucosa of patients with collagenous and ulcerative colitis. As the transcription factor nuclear factor kappaB (NFkappaB) is a major inducer of iNOS gene expression, we compared activation and transcriptional activity of NFkappaB in colonic mucosal biopsies from these patients. PATIENTS: Eight patients with collagenous colitis, six with relapsing ulcerative colitis, and eight with uninflamed bowel were studied. METHODS: NFkappaB DNA binding activity was assessed by electrophoretic mobility shift assay and inhibitor of NFkappaB (IkappaB) kinase (IKK) activity by immunocomplex kinase assay. In vivo recruitment of NFkappaB to the iNOS promoter was determined by chromatin immunoprecipitation analysis and transcriptional activity by NFkappaB gene expression profiling arrays. Cells showing NFkappaB activation were identified by immunohistochemistry. RESULTS: In collagenous and ulcerative colitis, as opposed to uninflamed bowel, IKKbeta activity and strong NFkappaB DNA binding gave rise to activation of identical NFkappaB subunits and recruitment of transcriptionally active p65 to the iNOS promoter. In collagenous colitis, activated NFkappaB was observed only in epithelial cells while up to 10% of lamina propria macrophages showed activation in ulcerative colitis. CONCLUSIONS: In collagenous and ulcerative colitis, colonic mucosal NFkappaB is activated and recruited to the iNOS promoter in vivo via an IKKbeta mediated pathway. As collagenous colitis is not associated with tissue injury, these data challenge the prevailing view that activation of NFkappaB per se mediates tissue injury. Our results suggest that downstream inflammatory reactions leading to tissue damage originate in lamina propria immune cells, as increased NFkappaB activity in collagenous colitis was localised solely in epithelial cells, but present also in macrophages in ulcerative colitis.

High glucose impairs superoxide production from isolated blood neutrophils.

OBJECTIVE: Superoxide (O(2)(-)), a key antimicrobial agent in phagocytes, is produced by the activity of NADPH oxidase. High glucose concentrations may, however, impair the production of O(2)(-) through inhibition of glucose-6-phosphate dehydrogenase (G6PD), which catalyzes the formation of NADPH. This study measured the acute effects of high glucose or the G6PD inhibitor dehydroepiandrosterone (DHEA) on the production of O(2)(-) from isolated human neutrophils. DESIGN: Laboratory studies of short-term cultures of neutrophil granulocytes. PARTICIPANTS: Healthy subjects. INTERVENTIONS: Neutrophils were isolated from peripheral blood and incubated for 1 h in Krebs-Ringer buffer containing 5, 10, or 25 mM glucose, 5 mM glucose with 0, 5, or 20 mM mannitol, or 5 mM glucose with 0, 1, 10, or 100 micro M DHEA. O(2)(-) production was induced by N-formyl-methionyl-leucyl-phenylalanine and measured by the cytochrome c reduction assay. Potential scavenging of O(2)(-) by glucose, mannitol, or DHEA was assessed in a cell free system using the pyrogallol assay. MEASUREMENTS AND RESULTS: Incubation of neutrophils with glucose dose-dependently reduced O(2)(-) production, which was 50% decreased at 25 mM glucose. Also DHEA reduced the production of O(2)(-) dose-dependently, whereas production rates were unaffected by mannitol. Neither glucose, mannitol, nor DHEA scavenged O(2)(-). CONCLUSIONS: High extracellular glucose concentrations acutely reduce O(2)(-) production from activated neutrophils possibly through inhibition of G6PD. If this occurs in vivo, microbial killing by neutrophils may be impaired during acute hyperglycemia, as observed after major surgery, trauma, or severe infection.

Superoxide production and expression of NAD(P)H oxidases by transformed and primary human colonic epithelial cells.

BACKGROUND: Superoxide (O(2)(-)) generation through the activity of reduced nicotinamide dinucleotide (NADH) or reduced nicotinamide dinucleotide phosphate (NADPH) oxidases has been demonstrated in a variety of cell types, but not in human colonic epithelial cells. AIMS: To measure O(2)(-) production and effects of modulators of NAD(P)H oxidase activity and inhibitors of potential O(2)(-) generating enzymes in cultures of human colonic epithelial cells. Expression of the catalytic subunits of NAD(P)H oxidase, Nox1 and gp91(phox) (phox, phagocytic oxidase), and the membrane bound subunit p22(phox) was assessed. METHODS: The transformed colonic epithelial cell lines (DLD-1, HT-29, and Caco-2) were studied at subconfluence, confluence, and after differentiation. Primary colonic epithelial cells were isolated from mucosal biopsies from the normal human colon. Extracellular O(2)(-) production was measured by the cytochrome c reduction assay or luminol enhanced luminescence. Nox1, gp91(phox), and p22(phox) mRNA expression was assessed in colonic epithelial cells and blood neutrophils by reverse transcriptase-polymerase chain reaction. RESULTS: Production rates of O(2)(-) were higher in subconfluent transformed cells (mean (SEM) 35.8 (4.2) nmol/mg of protein/h) and primary cells (40.4 (5.9)) than in confluent transformed cells (6.0 (0.9); p<0.01). The oxidoreductase inhibitor diphenylene iodonium significantly inhibited O(2)(-) production whereas NADPH and NADH increased production rates. In contrast, O(2)(-) was unaffected by phorbol myristate ester, N(G)-nitro-L-arginine methyl ester, indomethacin, or allopurinol. Nox1 mRNA was expressed in all colonic epithelial cells whereas gp91(phox) was detected only in HT-29 cells and neutrophils. p22(phox) was expressed in all cell types. CONCLUSIONS: Cultures of transformed and primary epithelial cells from human colon may produce extracellular O(2)(-) through an NAD(P)H oxidase expressing Nox1 and p22(phox).

Constitutive expression of inducible nitric oxide synthase in the normal human colonic epithelium.

BACKGROUND: Inducible nitric oxide synthase (iNOS) in the human colon is considered expressed only in inflammatory states such as ulcerative or collagenous colitis. As subtle iNOS labelling was previously observed in some colonic mucosal biopsies from a heterogeneous group of controls with non-inflamed bowel, we studied whether bowel preparation with bisacodyl or polyethylene glycol prior to sigmoidoscopy might induce iNOS expression. METHODS: Ten healthy, non-smoking male subjects were investigated. Mucosal biopsies were taken from the sigmoid colon prior to bowel preparation and again 12 h after rectal administration of bisacodyl or polyethylene glycol in randomized order. Expression of iNOS protein was quantified by Western blot analysis and localized by immunohistochemistry. RESULTS: iNOS was expressed in the colonic mucosal biopsies from all subjects and localized in the epithelial cells, particularly at the luminal border of the epithelial cells and more pronounced in the crypt epithelium. The expression of iNOS was unaffected by bowel preparation with bisacodyl or polyethylene glycol. CONCLUSIONS: iNOS is constitutively expressed in the normal colonic epithelium. The results suggest that synthesis of iNOS protein is unaffected by bowel preparation with the secretagogue laxative, bisacodyl, or polyethylene glycol.

Effects of topical ropivacaine on eicosanoids and neurotransmitters in the rectum of patients with distal ulcerative colitis.

BACKGROUND: Topical administration of lidocaine has been suggested to have beneficial clinical effects in patients with active ulcerative colitis, but the mechanism of action, if any, remains obscure. As local anaesthetics may exert anti-inflammatory actions through their inhibition of nervous reflexes, we have studied the local effects of a single rectal dose of ropivacaine gel on rectal concentrations of eicosanoids and neurotransmittors in patients with relapsing ulcerative colitis. METHODS: In a randomized, double-blind, placebo-controlled study, concentrations of leukotriene B4, thromboxane B2 and prostaglandin E2 in rectal dialysates and concentrations of substance P, neurokinin A, somatostatin, vasoactive intestinal polypeptide and calcitonin gene-related peptide in rectal biopsies from 19 patients with active, distally located, ulcerative colitis were measured before and after rectal administration of a 200-mg dose of ropivacaine- or placebo-gel by use of radioimmunoassays. For comparison with normal conditions, concentrations of neuropeptides were measured in another 19 patients with relapsing ulcerative colitis and 14 controls with non-inflamed colon. RESULTS: No significant changes in concentrations of eicosanoids or neuropeptides were observed after ropivacaine or placebo administration. Baseline concentrations of all neuropeptides, except somatostatin, were significantly lower in active ulcerative colitis than in controls with non-inflamed colon. CONCLUSIONS: These findings reveal no evidence of anti-inflammatory actions by ropivacaine in active ulcerative colitis and thus provide no rationale for topical treatment with local anaesthetics.

Colonic production of nitric oxide gas in ulcerative colitis, collagenous colitis and uninflamed bowel.

BACKGROUND: Nitric oxide (NO) produced in excess by the inflamed human colon is generally considered a pathway of mucosal damage. In an attempt to quantify colonic mucosal production of NO in various forms of colitis we performed 'steady-state' gas perfusion of whole colon in 11 patients with ulcerative colitis, 10 patients with collagenous colitis and 20 controls with uninflamed mucosa. METHODS: The tip of a Teflon tube was placed in the caecum during colonoscopy. Subsequently, argon was infused at a constant rate for 70-180 min. Argon and NO in gas sampled from the rectum were measured by neutron activation analysis and the chemiluminescence technique, respectively. RESULTS: The use of argon as a marker of colonic NO output was justified by complete recovery (96%+/-2; mean +/- s(x); n = 5) of argon in gas collected from the rectum and a constant output of NO at varying perfusion rates (25, 50 and 75 ml/min coefficient of variation 21%; n = 6). In patients with ulcerative colitis, colonic output of NO was 10-fold higher (P < 0.001) than in controls and positively correlated (P < 0.01) to indices of disease activity. In patients with collagenous colitis, colonic output of NO was 50-fold higher (P < 0.01) than in controls during periods with watery diarrhoea (n = 6), but within the range observed in ulcerative colitis in the absence of diarrhoea (n = 4). CONCLUSIONS: Argon gas perfusion of whole colon using chemiluminescence technique for measurement of NO is a reliable method for quantification of colonic mucosal NO production. Increased colonic production of NO in collagenous colitis, which exceeds the output observed even in extensive ulcerative colitis, militates against the theory that NO per se is a cause of mucosal injury.

Review article: the treatment of inflammatory bowel disease with 6-mercaptopurine or azathioprine.

The thioguanine derivative, azathioprine, is a prodrug of 6-mercaptopurine that is further metabolized by various enzymes present in the liver and gut. Azathioprine and 6-mercaptopurine have been used in the treatment of inflammatory bowel disease, i.e. ulcerative colitis and Crohn's disease, for more than 30 years. However, widespread use of azathioprine or 6-mercaptopurine in inflammatory bowel disease is of more recent origin, the primary reason being a long-standing debate on the efficacy of these agents in inflammatory bowel disease. Both drugs are slow acting, which is why clinical efficacy cannot be expected until several weeks or even months of treatment have elapsed. Consequently, azathioprine and 6-mercaptopurine have no place as monotherapy in the treatment of acute relapsing inflammatory bowel disease. Today, azathioprine and 6-mercaptopurine are the most commonly used immunomodulatory drugs in the treatment of inflammatory bowel disease. Their clinical effects are probably identical, although their exact mode of action is still unknown. The mode of action of azathioprine is thought to be multifactorial, including conversion to 6-mercaptopurine (which acts as a purine antimetabolite), possible blockade of thiol groups by alkylation, inhibition of several pathways in nucleic acid biosynthesis (preventing proliferation of cells involved in the determination and amplification of the immune response) and damage to DNA through the incorporation of thiopurine analogues. However, 6-thioguanine nucleotides may accumulate in toxic doses in myeloid precursor cells, resulting in life-threatening myelosuppression. Azathioprine and 6-mercaptopurine are further known to alter lymphocyte function, reduce the number of lamina propria plasma cells and affect natural killer cell function. The purpose of this comprehensive review is to suggest guidelines for the application of azathioprine and 6-mercaptopurine in the treatment of inflammatory bowel disease.

Expression of nitric oxide synthases and effects of L-arginine and L-NMMA on nitric oxide production and fluid transport in collagenous colitis.

BACKGROUND AND AIMS: Luminal nitric oxide (NO) is greatly increased in the colon of patients with collagenous and ulcerative colitis. To define the source and consequence of enhanced NO production we have studied expression of NO synthase (NOS) isoforms and nitrotyrosine in mucosal biopsies from these patients. In addition, effects on colonic fluid transfer caused by manipulating the substrate of NOS were studied in patients with collagenous colitis. PATIENTS: Eight patients with collagenous colitis, nine with active ulcerative colitis, and 10 with uninflamed bowel were included. METHODS: Expression of NOS isoforms was quantified by western blotting. Inducible NOS (iNOS) and nitrotyrosine were localised by immunohistochemistry. Modulation of NOS activity by topical N(G)-monomethyl-L-arginine (L-NMMA) or L-arginine was assessed during perfusion of whole colon. Plasma and perfusate nitrite/nitrate (NOx) was measured by Griess' reaction. RESULTS: Both in collagenous and ulcerative colitis, expression of iNOS was 10(2)-10(3) higher (p<0.001) than in uninflamed bowel and localised primarily to the epithelium. Endothelial NOS was evenly expressed in all groups while neuronal NOS was undetectable. Nitrotyrosine was markedly expressed in active ulcerative colitis but rarely detected in collagenous colitis and never in uninflamed bowel. In collagenous colitis, the output of NOx was markedly increased compared with uninflamed bowel (283 (58) v <37 nmol/min; p<0.01) and fluid was net secreted. L-NMMA reduced the output of NOx by 13-66% (95% confidence intervals) and secretion of fluid by 25-109% whereas L-arginine increased the output of NOx by 3-39% and secretion of fluid by 15-93%. CONCLUSIONS: In collagenous colitis, as opposed to ulcerative colitis, upregulation of iNOS occurs in the absence of nitrotyrosine formation and mucosal damage. Excess generation of NO may be the primary cause of diarrhoea in this condition.

Interleukin 10 (Tenovil) in the prevention of postoperative recurrence of Crohn's disease.

BACKGROUND AND AIMS: New lesions of Crohn's disease occur early after ileal or ileocolonic resection and ileocolonic anastomosis. We performed a double blind controlled trial to evaluate the safety and tolerance of recombinant human interleukin 10 (IL-10; Tenovil) in subjects operated on for Crohn's disease. We also assessed the effect of Tenovil in preventing endoscopic recurrence 12 weeks after surgery. METHODS: Patients with Crohn's disease who underwent curative ileal or ileocolonic resection and primary anastomosis were randomised within two weeks after surgery to receive subcutaneous Tenovil 4 microg/kg once daily (QD) (n=22) or 8 microg/kg twice weekly (TIW) (n=21), or placebo (QD or TIW) (n=22). An ileocolonoscopy was performed after 12 weeks of treatment. RESULTS: Compliance was excellent. The most frequently observed adverse events were mild and moderate in severity and equally distributed across treatment groups. Thirty seven patients in the pooled Tenovil group and 21 patients in the pooled placebo group were evaluable by endoscopy. At 12 weeks, 11 of 21 patients (52%) in the placebo group had recurrent lesions compared with 17 of 37 patients (46%) in the Tenovil group (ns). The incidence of severe endoscopic recurrence was similar in both groups (9%). CONCLUSION: Tenovil treatment for 12 consecutive weeks in patients with Crohn's disease after intestinal resection was safe and well tolerated. No evidence of prevention of endoscopic recurrence of Crohn's disease by Tenovil was observed.

Increased levels of specific leukocyte- and platelet-derived substances during normal anti-tetanus antibody synthesis in patients with inactive Crohn disease.

BACKGROUND: Crohn disease is considered a consequence of inappropriate upregulation of immune reactions evoked by the intestinal microflora or luminal antigens. Since the intestinal mucosa is continuously exposed to tetanus toxoid we studied the antibody response to tetanus toxoid booster immunization in patients with Crohn disease and the subsequent release of various inflammatory mediators and growth factors in blood. METHODS: Ten patients with inactive disease and no concurrent medication and 12 age-and gender-matched healthy volunteers with anti-tetanus antibody levels less than 0.1 IU/ml were inoculated with 1 ml (6 Lf units) of tetanus toxoid vaccine. The anti-tetanus antibody levels were determined in serum obtained before inoculation and after 7, 14 and 28 days, respectively. C-reactive protein (CRP), interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-alpha), histamine, vascular endothelial growth factor (VEGF), tissue inhibitor of metalloproteinases-1 (TIMP-1), plasminogen activator inhibitor type-1 (PAI-1) and myeloperoxidase (MPO) were determined in serum or plasma obtained on the same days. RESULTS: After inoculation anti-tetanus antibody levels were equally raised in patients and healthy volunteers. Pre-inoculation CRP levels were below the upper level of the normal range (<10 mg/l) in all inoculated patients/volunteers. No differences in IL-6, TNF-alpha, MPO or histamine levels between patients and healthy volunteers were observed. CRP levels were within the normal range and IL-6, TNF-alpha, MPO and histamine levels were unchanged in patients and volunteers during the study period. The levels of VEGF, TIMP-1 and PAI-1 were unchanged in the healthy volunteers during the study period, but were significantly (P < 0.05) increased at day 14 in patients with Crohn disease. At day 28 the levels had fallen to pre-inoculation levels, apart from PAI-1, which was still significantly (P<0.05) increased. CONCLUSIONS: In patients with inactive Crohn disease, booster immunization against tetanus toxoid seems to result in normal anti-tetanus antibody synthesis, but it may cause inappropriate release of certain bioactive substances, which are known to play a major role in modulation of the inflammatory response.

Eradication of Helicobacter pylori compared with long-term acid suppression in duodenal ulcer disease. A randomized trial with 2-year follow-up. The Danish Ulcer Study Group.

BACKGROUND: Trials evaluating long-term management of duodenal ulcer disease have mainly been focused on recurrence of ulcers, disregarding effects on dyspeptic and reflux symptoms. Profound acid inhibition with a proton pump inhibitor is the gold standard therapy in acid-related diseases. We aimed to compare the symptomatic effects of eradication therapy with those of long-term omeprazole treatment in a design with periods both with and without acid inhibition. METHODS: Patients with active duodenal ulcer were randomized either to omeprazole, 20 mg twice daily until healing, followed by omeprazole, 20 mg/ day for 1 year, or to eradication therapy (metronidazole, amoxicillin, and omeprazole for 2 weeks) followed by placebo for 1 year. All patients were followed up passively for an additional year. Clinical controls were performed every 2 months the 1st year (maintenance phase) and every 6 months during the passive follow-up phase. The study was multicentric and double-blind. The primary end-point was discontinuation of treatment, irrespective of reason. RESULTS: Two hundred and seventy-six patients were randomized (139 in the eradication treatment group). In the maintenance phase there were no differences in the reporting of dyspeptic symptoms or in premature withdrawal. In the passive follow-up phase only five patients in the eradication therapy group discontinued owing to relapse of dyspeptic symptoms or ulcer, compared with 51 patients initially randomized to long-term omeprazole. There were no differences in reflux symptoms or in the development of reflux oesophagitis. CONCLUSIONS: Eradication therapy and long-term omeprazole are equally effective in controlling dyspeptic symptoms and reflux in duodenal ulcer patients with healed ulcers. One-quarter of the duodenal ulcer patients who start eradication therapy continue to be symptomatic or fail therapy for other reasons over a 2-year period. Eradication therapy does not increase the risk of reflux in ulcer patients.

IOIBD questionnaire on the clinical use of azathioprine, 6-mercaptopurine, cyclosporin A and methotrexate in the treatment of inflammatory bowel diseases.

OBJECTIVE: To obtain information on the clinical experience with azathioprine (AZA), 6-mercaptopurine (6-MP), cyclosporin A (CyA) and methotrexate (MTX) in the treatment of patients with inflammatory bowel disease (IBD) by gastroenterologists and internists in different countries. DESIGN: A questionnaire designed by the International Organization for the Study of Inflammatory Bowel Disease (IOIBD) was mailed to 300 gastroenterologists, living in North America (n = 76) and Europe (n = 224) (12 countries), to obtain information on clinical experience. PARTICIPANTS: More than half of the respondents (168/298; 56.4%) worked in university hospitals and 58/298 (19.5%) in general (non-university) hospitals. Two-thirds (65%) had more than 10 years' experience in gastroenterology. RESULTS: The respondents had personal experience with AZA (88.4%), 6-MP (33.3%), CyA (48.7%) and MTX (36.3%). AZA was prescribed more frequently in Europe (92.6%) than in North America (74.2%) (P = 0.0002), 6-MP less frequently by the European than the North American respondents (23.8 and 53.3% respectively, P = 0.0001). Two-thirds (69.7%) usually prescribed AZA together with steroids to Crohn's disease patients; 62.4% of the respondents prescribed AZA for periods longer than 24 months. For ulcerative colitis, 77.9% had experience with AZA (Europe > North America, P = 0.0001). AZA had been prescribed by 69 respondents to pregnant patients, without apparent toxicity. Acute pancreatitis had been observed after AZA by 56.7% respondents; 25 malignancies were mentioned (six lymphoma, three leukaemia, three colon cancer, four renal carcinoma, nine others). CyA had been prescribed in acute ulcerative colitis by 140/291 respondents (North America 45.1%, Europe 49.1 %); of all respondents 63.9% treated < 5 patients with CyA, 36.1% 6-20 cases. CyA results were considered good in 29.5%, acceptable but with recurrences in 58.6%, and poor in 14.3%. MTX was prescribed in North America by 47.8% of the respondents, and by 33.9% in Europe (not significant). Several significant differences were observed between the prescription behaviour of respondents working at university hospitals and non-university hospitals, in particular in relation to participation in clinical trials. CONCLUSIONS: Considerable experience exists in the use of immunosuppressive therapy in IBD; however, differential prescription behaviour exists in the choice of immunosuppressives between North America and Europe. These IOIBD study results may contribute to a better insight in the daily use of immunosuppressive agents in IBD by gastroenterologists and other specialists.

Selective inhibitors of COX-2--are they safe for the stomach?

NSAIDs are widely used and beneficial for patients with inflammatory pain. However, NSAIDs cause significant adverse upper gastrointestinal effects, including increased mortality from serious ulcer complications. NSAIDs exert their anti-inflammatory effects by inhibiting the activity of the COX enzyme, which was recently shown to exist in two isoforms, a constitutive COX-1 and an inducible COX-2. The latter isoform is induced in inflammation, while the former is responsible for prostaglandin effects on platelet function and gastric mucosal defense. Two specific COX-2 inhibitors have recently been introduced into the market. The available data from clinical trials indicate that these new drugs have anti-inflammatory and analgesic effects similar to those of conventional NSAIDs, but reduced rates of adverse upper gastroduodenal effects, which are similar to those observed with placebo. This difference in rates of adverse effects might imply improved safety for patients requiring anti-inflammatory treatment. It has, however, to be kept in mind that specific COX-2 inhibitors lack cardiovascular protective effects. Considering the high consumption rate of NSAIDs to achieve pain relief in arthritis and other musculo-sceletal diseases, the reduced risk of gastrointestinal ulcers and ulcer complications may have a positive impact on population health and health economy.

Review article: the potential role of nitric oxide in chronic inflammatory bowel disorders.

The aetiology of the chronic inflammatory bowel diseases-ulcerative colitis and Crohn's disease-as well as 'microscopic colitis'-both collagenous (COC) and lymphocytic colitis (LC)-remains unknown. Autoimmune mechanisms, cytokine polymorphism, commensal bacteria, infectious agents and vascular impairment have all been proposed as playing important roles in the pathogenesis of this spectrum of diseases. A variety of proinflammatory mediators, including tumour necrosis factor alpha, interleukin-1beta, interferon gamma, leukotriene B4 and platelet activating factor, promote the adherence of phagocytes to the venular endothelium and extravasation of these cells into the colonic mucosa. In addition to large amounts of nitric oxide (NO), injurious peroxynitrite may be formed in the epithelium by the inducible nitric oxide synthase (iNOS), which is considered to elicit cytotoxicity by the generation of superoxide with reduced L-arginine availability. In active ulcerative colitis, and to a lesser extent in Crohn's disease, a greatly increased production of NO has been demonstrated by indirect and direct measurements. Surprisingly, even higher rates of production have been observed in COC-a condition which is never associated with injurious inflammation. The latter observation favours the notion that NO promotes mucosal integrity. Further evidence for a protective role of NO in chronic inflammatory bowel disorders is provided by the observation of increased susceptibility to the induction of experi mental colitis in 'knock-out' mice deficient in iNOS. Selective inhibitors of iNOS activity, as well as topical L-arginine, may therefore prove beneficial in inflammatory bowel disease by reducing the production of superoxide by iNOS, while only the former option may be expected to reduce diarrhoea in chronic inflammatory bowel disorders. Clearly, further experimental work needs to be done before testing topical L-arginine in human inflammatory bowel disease.

Soluble mediators and the interaction of drugs in IBD.

The chronic idiopathic bowel diseases (IBD) - Crohn's disease and ulcerative colitis - are considered to be the result of an unrestrained inflammatory reaction. Although an explanation for the etiopathogenesis has still not emerged, the explosion of information on the inflammatory process is expected to yield a multitude of drugs targeted at particular elements of the inflammatory process. The final common pathway of immune activation in IBD is the local influx of monocytes, macrophages and polymorphonuclear neutrophils (PMNs). The processes which account for the recruitment of these cells include cytokine generation, complement activation and eicosanoid biosynthesis. Once the influx of PMNs and macrophages occurs, an increased production of platelet-activating factor (PAF) and leukotrienes (LTs), in particular LTB(4), results in the secondary amplification of the inflammatory response, which provides the clinical manifestations of IBD. Other important soluble mediators of inflammation include complement-derived and chemotactic peptides, specific adhesion molecules, neuropeptides and reactive metabolites of oxygen and nitrogen. Current established therapies, such as glucocorticoids and 5-aminosalicylic acid (5-ASA), inhibit raised concentrations of these interdependent soluble mediators of inflammation, which may amplify one another or have parallel effects. Future medical options for treatment of IBD aim at removing perpetuating antigens or inhibiting the entry of inflammatory cells by manipulating adhesion molecules, by blocking the proinflammatory molecules, or by preserving endogenous suppressive molecules or correcting genetic defects. However, it remains to be defined whether targeting multiinflammatory actions or a single key pivotal process is the better therapeutic strategy and whether subgroups of IBD with different clinical courses will require different treatment approaches.

From basic science to future medical options for treatment of ulcerative colitis.

Both ulcerative colitis (UC) and Crohn's disease are considered the result of an unrestrained inflammatory reaction, but an explanation for the aetiopathogenesis has still not emerged. Until the predisposing and trigger factors have been clearly defined, therapeutic and preventive strategies for these disorders must, therefore, rely on interrupting or inhibiting the immunopathogenic mechanisms involved. Current therapies, such as glucocorticoids and 5-aminosalicylic acid, inhibit raised concentrations of interdependent, soluble mediators of inflammation, which may amplify one another or have parallel effects. Future medical options for treatment of UC aim at removing perpetuating antigens, blocking entry of inflammatory cells by manipulating adhesion molecules, targeting soluble mediators of inflammation by blocking proinflammatory molecules or by preserving endogenous suppressive molecules, or correcting genetic defects. It remains, however, to be determined whether targeting multi-inflammatory actions or a single key pivotal process is the better therapeutic strategy and whether subgroups of UC with different clinical courses will require different treatment approaches.

Reappraisal of bicarbonate secretion by the human oesophagus.

BACKGROUND AND AIMS: Administration of omeprazole to healthy volunteers was recently reported to increase proximal duodenal mucosal bicarbonate secretion. As human oesophagus also secretes bicarbonate, the hypothesis was tested that omeprazole may stimulate oesophageal bicarbonate secretion and thus contribute to the therapeutic efficacy of the drug in gastro-oesophageal reflux disease. SUBJECTS AND METHODS: In nine healthy volunteers, oesophageal "steady state" perfusion of a 10 cm open segment of distal oesophagus was performed twice in random order. The volunteers were pretreated with either 60 mg/day omeprazole for three days and 80 mg intravenous omeprazole before perfusion or 600 mg/day ranitidine for three days and 50 mg/h intravenously during the perfusion. Saliva and samples of aspirate from the perfused oesophagus and stomach were collected and bicarbonate concentrations were measured. RESULTS: The median rates (95% confidence intervals) of intrinsic oesophageal bicarbonate secretion, corrected for contaminating salivary and gastric bicarbonate, were 89 (33-150) and 121 (63-203) mumol/h/10 cm (p > 0.5) in omeprazole and ranitidine treated subjects respectively. Salivary and gastric bicarbonate contaminating the oesophagus accounted for 14% and 3%, respectively, of total oesophageal bicarbonate output. CONCLUSIONS: Bicarbonate secretory capacity of the human oesophagus is less than previously assumed, and the clinical relevance of intrinsic oesophageal bicarbonate for mucosal defence may be overestimated. As omeprazole and ranitidine did not affect bicarbonate secretion differently there was no evidence that omeprazole acts on bicarbonate secretory cells in the oesophageal mucosa.