Omeprazole and bleeding peptic ulcer, or "how case-control studies can tell you what you suspected all along".
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Anti-Inflammatory Agents, Non-Steroidal↗
Biomedical subjects
C J Hawkey
Publications and source records attributed to C J Hawkey.
Is Helicobacter pylori eradication useful in patients taking NSAIDs?
It has become clear that Helicobacter pylori and non-steroidal anti-inflammatory drugs (NSAIDs) account for the vast majority of peptic ulcers and their complications. Although gastric or duodenal ulceration caused by H. pylori or NSAIDs is very similar, the underlying processes are quite different. Given the possibility that H. pylori eradication might represent a valuable approach to the management of patients taking NSAIDs, a controlled clinical trial was performed in patients with current or previous endoscopically documented NSAID-associated gastric or duodenal ulceration and/or moderate-to-severe dyspepsia at study entry. Patients received either H. pylori eradication therapy or omeprazole alone. H. pylori eradication did not prevent ulcer recurrence during a six-month assessment; indeed, it retarded healing of gastric ulcers. The hypothesis that dyspepsia would be prevented by H. pylori eradication was not confirmed either.
Anti-Inflammatory Agents, Non-Steroidal↗
Allelic diversity of the Helicobacter pylori vacuolating cytotoxin gene in South Africa: rarity of the vacA s1a genotype and natural occurrence of an s2/m1 allele.
We describe the rarity of Helicobacter pylori strains of vacuolating cytotoxin type s1a (the type most commonly associated with peptic ulceration in the United States) among black and mixed-race South Africans. We also provide the first description of a naturally occurring strain with the vacA allelic structure s2/m1.
Alleles↗
Simple and accurate PCR-based system for typing vacuolating cytotoxin alleles of Helicobacter pylori.
Alleles of the vacuolating cytotoxin gene (vacA) of Helicobacter pylori vary between strains, particularly in the region encoding the signal sequence (which may be type s1 or s2) and the midregion (which may be type m1 or m2). Using a PCR-based typing system developed in the United States, we showed that 36 strains from Asia and South America were all vacA signal sequence type s1; 3 were midregion type m1 and 11 were m2, but 22 could not be typed for the vacA midregion. All strains possessed cagA (cytotoxin-associated gene A), another virulence marker. vacA nucleotide sequence analysis showed that midregion typing failure was due to base substitutions at the primer annealing sites. Using the new sequence data, we developed two new PCR-based vacA midregion typing systems, both of which correctly typed 41 U.S. strains previously typed by the old system and successfully typed all 36 of the non-U.S. strains. All previously untypeable strains were vacA m1, other than one m1/m2 hybrid. In summary, we describe and validate a simple PCR-based system for typing vacuolating cytotoxin (vacA) alleles of H. pylori and show that this system correctly identifies the signal and midregion types of vacA in 77 strains from Asia and North and South America.
Alleles↗
Phenotypic and functional characterisation of myofibroblasts, macrophages, and lymphocytes migrating out of the human gastric lamina propria following the loss of epithelial cells.
BACKGROUND: The basement membrane of human colonic mucosa contains numerous discrete pores. We have recently shown that following loss of the surface epithelium, many cells migrate out of the colonic lamina propria via basement membrane pores. AIMS: To characterise cells migrating out via basement membrane pores of the human gastric lamina propria, following loss of the surface epithelium. METHODS: Fresh human gastric mucosal samples were completely denuded of epithelial cells and placed in culture. Tissue samples were studied by electron microscopy (EM) and cells by EM, FACS analysis, immunohistochemistry, and reverse transcription polymerase chain reaction (RT-PCR). RESULTS: EM showed numerous discrete pores (0. 65-8.29 microm in diameter) in the subepithelial basement membrane. During culture of mucosal samples denuded of epithelial cells, lymphocytes, macrophages, and myofibroblasts migrated out of the lamina propria via the basement membrane pores. The lymphocytes were predominantly CD45RO+ and CD69+ T cells. Macrophages were shown to express cyclooxygenase (COX) 1 and 2 enzymes. Myofibroblasts were established in culture and, despite prolonged culture and passage, retained their phenotype. They expressed mRNA and protein for COX 1 and 2 enzymes and their release of prostaglandin E2 was inhibited by selective COX 1 and 2 inhibitors. CONCLUSIONS: Lamina propria cells migrating out of cultured denuded gastric mucosal samples have been characterised phenotypically and functionally. Such cells would be suitable for studies of their interactions with epithelial cells and also with Helicobacter pylori and its products.
Basement Membrane↗
Expression of cyclooxygenase 1 and 2 by human gastric endothelial cells.
BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenase (COX) and cause gastric ulceration. NSAIDs also impair granulation tissue angiogenesis and healing of established gastric ulcers in humans. The mechanism whereby NSAIDs inhibit granulation tissue angiogenesis is unknown but may involve inhibition of either or both COX isoforms (COX-1 and COX-2). AIMS: To investigate COX expression by human gastric endothelial (HuGE) cells during angiogenesis in vitro. METHODS: COX-1 and COX-2 expression by HuGE cells was investigated by western blot analysis, indirect immunofluorescence, reverse transcriptase polymerase chain reaction, and measurement of prostaglandin E(2) synthesis. Plating onto basement membrane matrix and stimulation by phorbol ester were used as in vitro models of angiogenesis. RESULTS: Under normal culture conditions (30% serum), HuGE cells expressed COX-1 and low levels of COX-2. COX-2 expression was induced in HuGE cells in both angiogenesis models. Prostaglandin E(2) production and tubular structure formation by HuGE cells on basement membrane matrix was significantly inhibited by a selective COX-2 inhibitor (NS-398). CONCLUSION: Angiogenesis by HuGE cells in vitro was associated with induction of functional COX-2 expression. A selective COX-2 inhibitor significantly decreased HuGE cell angiogenesis on basement membrane matrix. Extrapolation of these data to human gastric ulcer angiogenesis in vivo suggests that selective COX-2 inhibitors could delay gastric ulcer healing to the same extent as traditional NSAIDs which are non-selective COX inhibitors.
Blotting, Western↗
TGF-alpha reduces bradykinin-stimulated ion transport and prostaglandin release in human colonic epithelial cells.
The effect of chronic exposure to transforming growth factor-alpha (TGF-alpha) on bradykinin-stimulated acute prostanoid production and ion secretion in monolayers of HCA-7 colony 29 colonic epithelial cells has been studied. Monolayers synthesized prostaglandin E2 (PGE2) at a basal rate of 2.10 +/- 0.31 pg. monolayer-1. min-1 over 24 h. Bradykinin (10(-8)-10(-5) M) dose dependently increased acute PGE2 release by three orders of magnitude. This was associated with a rise in cAMP from 1.60 +/- 0.14 to 2.90 +/- 0.1 pmol/monolayer (P < 0.02) and a dose-dependent increase in short-circuit current (SCC). When monolayers were primed by a 24-h exposure to TGF-alpha, basal PGE2 release rose to 6.31 +/- 0.38 pg. monolayer-1. min-1 (TGF-alpha concn 10 ng/ml; P = 0.001). However, the stimulation of acute prostaglandin release, intracellular cAMP, and increased SCC by bradykinin was significantly reduced by preincubation with TGF-alpha. Priming with PGE2 (10(-8)-10(-6) M) over 24 h mimicked the effect of TGF-alpha on bradykinin-induced changes in cAMP and SCC. These data suggest that enhanced chronic release of prostaglandins in response to stimulation with TGF-alpha may downregulate acute responses to bradykinin. In vivo, TGF-alpha could have an important modulatory function in regulating secretion under inflammatory conditions.
Arachidonic Acid↗
Human colonic subepithelial myofibroblasts modulate transepithelial resistance and secretory response.
The epithelium of the gastrointestinal tract transports ions and water but excludes luminal microorganisms and toxic molecules. The factors regulating these important functions are not fully understood. Intestinal myofibroblasts lie subjacent to the basement membrane, at the basal surface of epithelial cells. We recently showed that primary cultures of adult human colonic subepithelial myofibroblasts express cyclooxygenase (COX)-1 and COX-2 enzymes and release bioactive transforming growth factor-beta (TGF-beta). In this study we have investigated the role of normal human colonic subepithelial myofibroblasts in the regulation of transepithelial resistance and secretory response in HCA-7 and T84 colonic epithelial cell lines. Cocultures of epithelial cells-myofibroblasts and medium conditioned by myofibroblasts enhanced transepithelial resistance and delayed mannitol flux. A panspecific antibody to TGF-beta (but not piroxicam) antagonized this effect. In HCA-7 cells, myofibroblasts downregulated secretagogue-induced change in short-circuit current, and this effect was reversed by pretreatment of myofibroblasts with piroxicam. In contrast to HCA-7 cells, myofibroblasts upregulated the agonist-induced secretory response in T84 cells. This study shows that intestinal subepithelial myofibroblasts enhance barrier function and modulate electrogenic chloride secretion in epithelial cells. The enhancement of barrier function was mediated by TGF-beta. In contrast, the modulation of agonist-induced change in short-circuit current was mediated by cyclooxygenase products. These findings suggest that colonic myofibroblasts regulate important functions of epithelial cells via distinct secretory products.
Biological Transport↗
Normal human colonic subepithelial myofibroblasts enhance epithelial migration (restitution) via TGF-beta3.
After injury and loss of epithelial cells, intestinal barrier function is reestablished by migration of viable epithelial cells from the wound edge (restitution). Myofibroblasts are located close to the basal surface of epithelial cells. This study aimed to investigate the role of human colonic subepithelial myofibroblasts in epithelial restitution. Primary cultures of subepithelial myofibroblasts were established. Monolayers of the epithelial cell lines IEC-6 and T84 were "wounded" in a standard manner to create an in vitro model of restitution. Migration of epithelial cells across the wound edge was assessed following culture in myofibroblast-conditioned medium. Myofibroblast expression of transforming growth factor (TGF)-beta isoforms was examined using RT-PCR, and TGF-beta isoform bioactivity was assessed using Mv 1 Lu bioassay. Myofibroblast-conditioned medium, via a TGF-beta-dependent pathway, significantly enhanced migration of epithelial cells across the wound edge and significantly inhibited cell proliferation in wounded monolayers. Messenger RNA for TGF-beta1, -beta2, and -beta3 was detected in the myofibroblasts, and Mv 1 Lu bioassay showed the presence of predominantly bioactive TGF-beta3. This study shows that human colonic subepithelial myofibroblasts secrete predominantly bioactive TGF-beta3 and enhance restitution in wounded epithelial monolayers via a TGF-beta-dependent pathway.
Animals↗
What do we do about Helicobacter pylori?
Heliobacter pylori and nonsteroidal anti-inflammatory drugs (NSAIDs) cause ulcers by different mechanisms. Under some circumstances, patients infected with H pylori may be less prone to NSAID-associated ulcers than those who are H pylori-negative. Eradication trials have yielded differing results. However, those who have studied patients who have a past history of ulcer disease and are already established on NSAIDs have shown no benefit from H pylori eradication.
Anti-Inflammatory Agents, Non-Steroidal↗
Gastrointestinal effects of COX-2 inhibitors.
The developing popularity of non-steroidal anti-inflammatory drugs (NSAIDs) over the last 100 years has been paralleled by an increase in associated complications, particularly affecting the gastrointestinal (GI) tract [1]. Over this period, there have been several attempts to develop less toxic NSAIDs, most of which have been unsuccessful. Since the discovery that the enzyme cyclooxygenase (COX) exists as two isoforms, the largely constitutive COX-1 and the mainly inducible COX-2, much interest has centred on the development of drugs capable of selectively inhibiting COX-2. Early studies that investigated specific COX-2 inhibitors (with no effect on the COX-1 isoform over the whole range of concentrations achieved in clinical usage) are encouraging, as they demonstrate that these drugs have fewer effects on gastroduodenal mucosa than standard NSAIDs given at equivalent doses. Further clinical experience with these agents outside trial settings and additional studies to assess the role of COX-2 when induced in the GI tract are needed, before such agents can be safely recommended for widespread prescribing.
Journal Article↗
The treatment and prophylaxis of nonsteroidal anti-inflammatory drug (NSAID)-associated ulcers and erosions.
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Anti-Inflammatory Agents, Non-Steroidal↗
Randomised controlled trial of Helicobacter pylori eradication in patients on non-steroidal anti-inflammatory drugs: HELP NSAIDs study. Helicobacter Eradication for Lesion Prevention.
BACKGROUND: The effect of Helicobacter pylori in patients receiving non-steroidal anti-inflammatory drugs (NSAIDs) is unclear. We investigated the effects of H. pylori eradication in patients with current or previous peptic ulceration, dyspepsia, or both who continued to use NSAIDs. METHODS: 285 patients were randomly assigned omeprazole 20 mg, amoxycillin 1000 mg, and clarithromycin 500 mg, twice daily (n=142, H. pylori eradication treatment), or omeprazole with placebo antibiotics (n=143, controls) for 1 week. All patients received omeprazole 20 mg once daily for 3 weeks until endoscopy, and, if the ulcer was not healed, 40 mg once daily until repeat endoscopy at 8 weeks. Ulcer-free patients with mild dyspepsia continued NSAIDs but not antiulcer treatment. We investigated ulcers with endoscopy at 1, 3, and 6 months and with carbon-13-labelled urea breath test at 3 months. FINDINGS: The estimated probability of being ulcer-free at 6 months was 0.56 (95% CI 0.47-0.65) on eradication treatment and 0.53 (0.44-0.62) on on control treatment (p=0.80). Time to treatment failure did not differ between groups for ulcers or dyspepsia alone, per-protocol analysis, or final H. pylori status. 66% (58-74) of the eradication group compared with 14% (8-20) of the control group had a final negative H. pylori result (p<0.001). Fewer baseline gastric ulcers healed among eradication-treatment patients than among controls (72 vs 100% at 8 weeks, p=0.006). INTERPRETATION: H. pylori eradication in long-term users of NSAIDs with past or current peptic ulcer or troublesome dyspepsia led to impaired healing of gastric ulcers and did not affect the rate of peptic ulcers or dyspepsia over 6 months.
Adolescent↗
Varying efficacy of Helicobacter pylori eradication regimens: cost effectiveness study using a decision analysis model.
OBJECTIVE: To determine how small differences in the efficacy and cost of two antibiotic regimens to eradicate Helicobacter pylori can affect the overall cost effectiveness of H pylori eradication in duodenal ulcer disease. DESIGN: A decision analysis to examine the cost effectiveness of eight H pylori eradication strategies for duodenal ulcer disease with and without 13C-urea breath testing to confirm eradication. MAIN OUTCOME MEASURES: Cumulative direct treatment costs per 100 patients with duodenal ulcer disease who were positive for H pylori. RESULTS: In model 1 the strategy of omeprazole, clarithromycin, and metronidazole alone was the most cost effective of the four strategies assessed. The addition of the 13C-urea breath test and a second course of omeprazole, clarithromycin, and metronidazole achieved the highest eradication rate (97%) but was the most expensive (62.63 pounds per patient). The cost of each additional effective eradication was 589.00 pounds (incremental cost per case) when compared with the cost of treating once only with omeprazole, clarithromycin, and metronidazole; equivalent to the cost of a patient receiving ranitidine for duodenal ulcer relapse for more than 15 years. Eradication strategies of omeprazole, amoxycillin, and metronidazole were less cost effective than omeprazole, clarithromycin, and metronidazole alone. In model 2 the addition of the 13C-urea breath test after treatment, and maintenance treatment, increased the cost of all the strategies and reduced the cost advantage of omeprazole, clarithromycin, and metronidazole alone. CONCLUSION: Small differences in efficacy can influence the comparative cost effectiveness of strategies for eradicating H pylori. Of the strategies tested the most cost effective (omeprazole, clarithromycin, and metronidazole alone) was neither the least expensive (omeprazole, amoxycillin, and metronidazole alone) nor the most effective (omeprazole, clarithromycin, and metronidazole with further treatment for patients found positive for H pylori on 13C-urea breath testing). Cost effectiveness should be an important part of choosing an eradication strategy for H pylori.
Breath Tests↗
A novel flow cytometric assay for quantitating adherence of Helicobacter pylori to gastric epithelial cells.
Adherence may be an important virulence factor for Helicobacter pylori. Current methods available for quantitation of adherence are time consuming and liable to observer error. A new direct technique for fluorescent labelling of bacteria has been developed to quantitate adherence of H. pylori to epithelial cells by fluorescence activated cell sorting (FACS). Type strains of H. pylori, H. mustelae, H. cinaedi and H. fennelliae were grown microaerobically in broth culture for 24 h and fluorescently labelled by incubation with carboxyfluorescein diacetate succinimidyl ester (CFDA-SE) at 37 degrees C. After washing to remove excess CFDA-SE, bacteria were co-incubated (ratio 10:1) with gastric epithelial cells at 37 degrees C for up to 24 h. After washing to remove non-adherent bacteria, epithelial cells were detached with EDTA (2 mM) and fixed with formaldehyde for flow cytometry. Adherence was quantitated both in terms of the proportion of cells with adherent H. pylori and as the mean number of adherent bacteria per cell. All H. pylori strains adhered to gastric-type epithelial cells. The proportion of cells with bound bacteria varied from 40-99% and the number of bacteria per cell from 1-50, both of which correlated with microscopy (r = 0.6, and r = 0.8 respectively, n = 35). Time course studies demonstrated saturation of binding by H. pylori within 90 min. For H. mustelae, H. cinaedi and H. fennelliae the proportion of cells with bound bacteria varied from 5-15% and the mean number of bacteria per cell was < 4. Binding of H. pylori to epithelial cells could be partly blocked by pre-incubation with polyclonal anti-sera or using oligosaccharides against potential binding epitopes of gastric mucus. Fluorescent labelling of H. pylori with CFDA-SE in combination with flow cytometry provides a quick, specific, and sensitive method to quantitate in vitro the adherence of H. pylori.
Antibodies, Bacterial↗
Evolving strategies for managing nonsteroidal anti-inflammatory drug-associated ulcers: chairmen's introduction.
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Anti-Inflammatory Agents, Non-Steroidal↗
Progress in prophylaxis against nonsteroidal anti-inflammatory drug-associated ulcers and erosions. Omeprazole NSAID Steering Committee.
Four large clinical studies have shown that omeprazole, 20 mg once daily, is effective in preventing the significant gastroduodenal consequences of nonsteroidal anti-inflammatory drugs (NSAIDs). In the Scandinavian Collaborative Ulcer Recurrence (SCUR) study, patients were randomized (without initial endoscopy) to receive omeprazole or placebo for up to 3 months. Of the patients treated with omeprazole, 24.7% experienced treatment failure, compared with 50.0% of those on placebo. Fewer patients in the omeprazole group than in the placebo group developed a peptic ulcer (4.7% versus 16.7%, respectively) or dyspeptic symptoms (8.2% versus 20.0%, respectively). In the Omeprazole versus Placebo as Prophylaxis of Ulcers and Erosions from NSAID Treatment (OPPULENT) study, patients were also randomized to receive omeprazole or placebo. The estimated probability of remaining in remission for 6 months while receiving omeprazole was 0.78, compared with 0.53 for placebo. Fourteen (16.5%) patients on placebo developed peptic ulcer(s), compared with three (3.6%) patients on omeprazole. The Omeprazole versus Misoprostol for NSAID-Induced Ulcer Management (OMNIUM) study consisted of a healing and a prophylactic phase. Patients who successfully completed the healing phase were re-randomized to receive omeprazole, misoprostol, or placebo for up to 6 months. In patients receiving omeprazole, 36.5% experienced treatment failure, compared with 48.6% of those on misoprostol, and 67.7% of those on placebo. Omeprazole and misoprostol appeared to be equally effective in preventing gastric ulcer; by contrast, omeprazole was highly effective in preventing duodenal ulcer, when compared with misoprostol and placebo. The Acid Suppression Trial: Ranitidine versus Omeprazole for NSAID-Associated Ulcer Treatment (ASTRONAUT) study also consisted of a healing and a prophylactic phase. Patients who successfully completed the healing phase were re-randomized to receive omeprazole or ranitidine for up to 6 months. In patients receiving omeprazole, 26.2% experienced treatment failure, compared with 37.7% of those on ranitidine. The percentages of patients with a peptic ulcer relapse were 5.7% for omeprazole and 19.5% for ranitidine. The data show that omeprazole is an effective and well-tolerated agent for both primary and secondary (maintenance) prophylaxis in patients receiving NSAIDs.
Anti-Inflammatory Agents, Non-Steroidal↗
Practical management: a keypad-based interactive session.
If controlled therapeutic, epidemiologic, and pathologic data are to be put rationally into clinical practice, they need to be evaluated against real clinical scenarios. This was done by presenting the symposium delegates with a clinical case and then asking management questions, which were answered using a keypad system.
Anti-Inflammatory Agents, Non-Steroidal↗