The dynamics of the oesophageal squamous epithelium 'normalisation' process in patients with gastro-oesophageal reflux disease treated with long-term acid suppression or anti-reflux surgery

BACKGROUND

Proton pump inhibitors and laparoscopic anti-reflux surgery (LARS) offer long-term symptom control to patients with gastro-oesophageal reflux disease (GERD).

AIM

To evaluate the process of 'normalisation' of the squamous epithelium morphology of the distal oesophagus on these therapies.

METHODS

In the LOTUS trial, 554 patients with chronic GERD were randomised to receive either esomeprazole (20-40 mg daily) or LARS. After 5 years, 372 patients remained in the study (esomeprazole, 192; LARS, 180). Biopsies were taken at the Z-line and 2 cm above, at baseline, 1, 3 and 5 years. A severity score was calculated based on: papillae elongation, basal cell hyperplasia, intercellular space dilatations and eosinophilic infiltration. The epithelial proliferative activity was assessed by Ki-67 immunohistochemistry.

RESULTS

A gradual improvement in all variables over 5 years was noted in both groups, at both the Z-line and 2 cm above. The severity score decreased from baseline at each subsequent time point in both groups (P < 0.001, all comparisons), attaining a normal level by 5 years. Corresponding decreases in Ki-67 expression were observed (P < 0.001, all comparisons). No significant differences were found between esomeprazole treatment and LARS. Neither baseline severity score nor Ki-67 expression predicted the risk of treatment failure.

CONCLUSIONS

Five years of treatment is generally required before squamous epithelial cell morphology and proliferation are 'normalised' in patients with chronic GERD, despite endoscopic and symptomatic disease control. Control of the acid component of the refluxate seems to play the predominant role in restoring tissue morphology.

Long-term safety of proton pump inhibitor therapy assessed under controlled, randomised clinical trial conditions: data from the SOPRAN and LOTUS studies

BACKGROUND

Control of chronic gastro-oesophageal reflux disease may be achieved either by anti-reflux surgery (ARS) or by long-term medical therapy with proton pump inhibitors (PPIs). The primary efficacy results of the SOPRAN study, comparing long-term omeprazole use with open ARS, and the LOTUS study, comparing long-term esomeprazole use with laparoscopic ARS, have been reported. A secondary objective of these studies was to address the long-term safety of these respective therapeutic strategies and thereby provide a valid scientific platform for assessing long-term PPI safety.

AIM

To assess the safety of long-term PPI therapy with omeprazole and esomeprazole through analyses of data from the randomised SOPRAN and LOTUS studies.

METHODS

Safety data were collected from patients during the 12-year period of the SOPRAN study (n = 298) and the 5-year period of the LOTUS study (n = 514). Reported serious adverse events (SAEs) and changes in laboratory variables were analysed.

RESULTS

Across both studies, SAEs were reported at a similar frequency in the PPI and ARS treatment groups. Taking the time frames into consideration, the number of fatal SAEs in the two studies was low in both treatment groups. Laboratory results, including routine haematology and tests for liver enzymes, electrolytes, vitamin D, vitamin B12 , folate and homocysteine, showed no clinically relevant changes over time. As expected, gastrin and chromogranin A were elevated in the PPI groups, with the greatest increases observed in the first year.

CONCLUSION

No major safety concerns arose during 5-12 years of continuous PPI therapy. (ClinicalTrials.gov: NCT00251927 and NCT00256737).

Colon capsule endoscopy: European Society of Gastrointestinal Endoscopy (ESGE) Guideline

PillCam colon capsule endoscopy (CCE) is an innovative noninvasive, and painless ingestible capsule technique that allows exploration of the colon without the need for sedation and gas insufflation. Although it is already available in European and other countries, the clinical indications for CCE as well as the reporting and work-up of detected findings have not yet been standardized. The aim of this evidence-based and consensus-based guideline, commissioned by the European Society of Gastrointestinal Endoscopy (ESGE) is to furnish healthcare providers with a comprehensive framework for potential implementation of this technique in a clinical setting.

Colonic mucosal biopsies obtained during confocal endomicroscopy are pre-stained with fluorescein in vivo and are suitable for histologic evaluation

BACKGROUND AND STUDY AIMS

Confocal laser endomicroscopy (CLE) with intravenous infusion of fluorescein allows noninvasive, real-time in vivo visualization of gastrointestinal mucosa at ~ × 1000 magnification ("virtual biopsy"). Conventional biopsies obtained during these procedures serve as the reference and established diagnostic standard. The aim of the present study was to assess whether the standard histologic biopsies that are obtained during CLE retain fluorescein in the tissues and allow the visualization of mucosal structures without any additional staining.

PATIENTS AND METHODS

CLE optical imaging of the mucosa was performed in 16 patients who were undergoing CLE colonoscopy. Standard conventional biopsies were also obtained from both normal colonic mucosa and colonic polyps. De-paraffinized mucosal sections were examined under a fluorescence microscope for the presence and distribution of fluorescein, and then underwent immunostaining for expression of vascular endothelial growth factor (VEGF).

RESULTS

Standard mucosal biopsy sections from patients undergoing CLE displayed a strong fluorescence and showed well-delineated mucosal structures. In colonic adenomas, there was a 4.6-fold increased vascular permeability compared with normal mucosa (P<0.001), indicated by fluorescein leakage to the extravascular space. Immunostaining demonstrated an aberrantly increased expression of VEGF in the epithelium of colonic adenomas but not in the epithelium of normal mucosa or hyperplastic polyps.

CONCLUSIONS

This study shows for the first time that standard colonic biopsies obtained during CLE retain fluorescein, show excellent delineation of mucosal structures without additional staining, allow the evaluation of mucosal microvasculature and vascular permeability, and are suitable for immunostaining.

Colon capsule endoscopy vs. colonoscopy in patients at average or increased risk of colorectal cancer

BACKGROUND

Colon capsule endoscopy (CCE) is a new, non-invasive technology.

AIM

To conduct a prospective, multicentre trial to compare CCE and colonoscopy in asymptomatic subjects enrolled in screening or surveillance programmes for the detection of colorectal neoplasia.

METHODS

Patients underwent CCE on day one and colonoscopy (gold standard) on day two. CCE and colonoscopy were performed by independent endoscopists.

RESULTS

A total of 545 patients were recruited. CCE was safe and well-tolerated. Colon cleanliness was excellent or good in 52% of cases at CCE. Five patients with cancer were detected by colonoscopy, of whom two were missed by CCE. CCE accuracy for the detection of polyps ≥ 6 mm was 39% (95% CI 30-48) for sensitivity, 88% (95% CI 85-91) for specificity, 47% (95% CI 37-57) for positive predictive value and 85% (95% CI 82-88) for negative predictive value. CCE accuracy was better for the detection of advanced adenoma, in patients with good or excellent cleanliness and after re-interpretation of the CCE videos by an independent expert panel.

CONCLUSIONS

Although well-tolerated, CCE cannot replace colonoscopy as a first line investigation for screening and surveillance of patients at risk of cancer. Further studies should pay attention to colonic preparation (Clinicaltrial.gov number NCT00436514).

Review article: gene therapy, recent developments and future prospects in gastrointestinal oncology

BACKGROUND

Gene therapy consists of the introduction of genetic material into cells for a therapeutic purpose. A wide range of gene therapy vectors have been developed and used for applications in gastrointestinal oncology.

AIM

To review recent developments and published clinical trials concerning the application of gene therapy in the treatment of liver, colon and pancreatic cancers.

METHODS

Search of the literature published in English using the PubMed database.

RESULTS

A large variety of therapeutic genes are under investigation, such as tumour suppressor, suicide, antiangiogenesis, inflammatory cytokine and micro-RNA genes. Recent progress concerns new vectors, such as oncolytic viruses, and the synergy between viral gene therapy, chemotherapy and radiation therapy. As evidence of these basic developments, recently published phase I and II clinical trials, using both single agents and combination strategies, in adjuvant or advanced disease settings, have shown encouraging results and good safety records.

CONCLUSIONS

Cancer gene therapy is not yet indicated in clinical practice. However, basic and clinical advances have been reported and gene therapy is a promising, new therapeutic approach for the treatment of gastrointestinal tumours.

Endoscopic ultrasound-guided fine-needle aspiration for the diagnosis of solid pancreatic masses: the impact on patient-management strategy

BACKGROUND

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is a safe and accurate technique for diagnosing pancreatic cancer. However, its impact for management of these patients is poorly investigated.

AIMS

To investigate the diagnostic yield and the therapeutic impact of EUS-FNA in the management of solid pancreatic masses.

METHODS

One hundred consecutive patients who underwent EUS-FNA for a solid pancreatic mass were included. Aspirates were placed onto glass slides for cytological examination and microbiopsies were fixed in formaldehyde for histology. The impact on clinical management was analysed retrospectively according to different endpoints, such as its impact on indications for chemotherapy, surgery or appropriate follow-up modality.

RESULTS

Eight procedures were considered failures and two patients were lost to follow-up. A final diagnosis was obtained in 90 patients. The sensitivity, specificity and accuracy of combined cytology and histology for the diagnosis of malignant or potentially-malignant tumours were 78%, 75%, and 78% respectively. The sensitivity and accuracy of cytology alone were significantly higher than those of histology alone (P = 0.0003). By intention-to-diagnose analysis, EUS-FNA directly influenced the management strategy in 62 of 100 patients.

CONCLUSIONS

In patients with pancreatic mass and suspected malignancy, EUS-FNA provides an accurate diagnosis in approximately 80% of cases. EUS-FNA directly influences the management in two-thirds of patients.

Impaired intestinal barrier integrity in the colon of patients with irritable bowel syndrome: involvement of soluble mediators

BACKGROUND

Growing evidence suggests that patients with irritable bowel syndrome (IBS) have increased intestinal permeability. In addition, mucosal soluble mediators are involved in the pathophysiology of pain in IBS. We aimed to investigate (1) paracellular permeability in colonic biopsies of patients with IBS; and (2) the ability of soluble factors from colonic biopsies to reproduce these alterations in vitro.

METHODS

Paracellular permeability in colonic biopsies of healthy subjects and patients with IBS was measured by mounting the biopsies in Ussing chambers. Cleared supernatant (SUP) of the culture from colonic biopsies was collected and applied to Caco-2 cells for 48 h. Paracellular permeability and transepithelial resistance (TER) were evaluated. mRNA expression of the tight junction proteins, zonula occludens (ZO)-1 and occludin, was assessed in colonic biopsies. Abdominal pain was assessed using a validated questionnaire.

RESULTS

Permeability of colonic biopsies was significantly higher in patients with IBS compared to healthy subjects. These changes were associated with significantly lower expression of ZO-1 mRNA in biopsies of IBS as compared to healthy subjects. Compared to healthy subjects, SUP of IBS markedly reduced TER and significantly increased permeability in Caco-2 cells. SUP of IBS patients induced a significant decrease of ZO-1 mRNA in Caco-2 as compared to healthy subjects. SUP-induced increased paracellular permeability correlated with the severity of abdominal pain.

CONCLUSIONS

Our study shows that colonic soluble mediators are able to reproduce functional (permeability) and molecular (ZO-1 mRNA expression) alterations observed in IBS patients. These findings might pave the way both to identify novel biomarkers as well as new therapeutic targets in IBS.

Clinical trial: Radiofrequency energy delivery in proton pump inhibitor-dependent gastro-oesophageal reflux disease patients

BACKGROUND

Radiofrequency (RF) energy delivery is an endoscopic procedure developed for the treatment of gastro-oesophageal reflux disease.

AIM

To compare RF and a proton pump inhibitor strategy (PPI) in PPI-dependent patients by carrying out a prospective, randomized trial.

METHODS

Patients with PPI-dependent typical reflux symptoms were randomly allocated to either RF or PPI regimen alone. The primary endpoint, evaluated at 6-month, was defined as the possibility for the patient to stop or to decrease PPI use to <50% of the effective dose required at baseline.

RESULTS

In the RF group, 18/20 patients stopped (n = 3) or decreased (n = 15) PPI use as compared to eight of 16 in the PPI group (P = 0.01). None of the control patients could stop PPI. Health-related quality of life scores were not different between groups. No significant change in oesophageal acid exposure (OAE) was noted between baseline and 6-months after RF. No severe complication was reported.

CONCLUSIONS

Radiofrequency energy delivery is a safe and effective therapeutic option, allowing reduction in or discontinuation of PPI therapy in patients with PPI-dependent symptoms, without loss of quality of life. However, in a majority of patients, PPI therapy cannot be completely stopped. The efficacy of RF does not seem to be related to a decrease in OAE.

Review article: respiratory manifestations of gastro-oesophageal reflux disease

BACKGROUND

Respiratory manifestations represent one of the most prevalent and difficult-to-manage extra-oesophageal syndromes of gastro-oesophageal reflux disease.

AIMS

To review the epidemiology, pathophysiological mechanisms and therapeutic outcomes of reflux-related respiratory disorders.

METHODS

Search of the literature published in English using PubMed database.

RESULTS

There is a discrepancy between the high prevalence of reflux in asthmatics and the limited efficacy of antireflux therapies. Asthma per se may cause reflux. Patients with difficult-to-treat asthma and/or nocturnal symptoms should be screened for reflux. Reflux can induce chronic cough through different mechanisms including micro-aspiration and both local and central reflexes. Cough and reflux may precipitate each other. A meta-analysis found no significant difference between placebo and proton pump inhibitors in the resolution of cough. Encouraging results have been reported, following antireflux surgery in patients selected on the basis of pH-impedance monitoring. Attention has been drawn to obstructive sleep apnoea syndrome.

CONCLUSIONS

The role of gastro-oesophageal reflux disease in the pathogenesis of miscellaneous respiratory disorders has been discussed for decades and established in asthma and cough. However, no major therapeutic advances have been reported recently. Future trials should concentrate on patient selection and the control of efficacy using recently developed technologies, such as pH-impedance monitoring.

Enteric glia inhibit intestinal epithelial cell proliferation partly through a TGF-beta1-dependent pathway

Although recent studies have shown that enteric neurons control intestinal barrier function, the role of enteric glial cells (EGCs) in this control remains unknown. Therefore, our goal was to characterize the role of EGCs in the control of intestinal epithelial cell proliferation using an in vivo transgenic and an in vitro coculture model. Assessment of intestinal epithelial cell proliferation after ablation of EGCs in transgenic mice demonstrated a significant increase in crypt cell hyperplasia. Furthermore, mucosal glial network (assessed by immunohistochemical detection of S-100beta) is altered in colon adenocarcinoma compared with control tissue. In an in vitro coculture model of subconfluent Caco-2 cells seeded onto Transwell filters with EGCs, Caco-2 cell density and [3H]thymidine incorporation were significantly lower than in control (Caco-2 cultured alone). Flow cytometry analysis showed that EGCs had no effect on Caco-2 cell viability. EGCs induced a significant increase in Caco-2 cell surface area without any sign of cellular hypertrophy. These effects by EGCs were also seen in various transformed or nontransformed intestinal epithelial cell lines. Furthermore, TGF-beta1 mRNA was expressed, and TGF-beta1 was secreted by EGCs. Exogenously added TGF-beta1 reproduced partly the EGC-mediated effects on cell density and surface area. In addition, EGC effects on Caco-2 cell density were significantly reduced by a neutralizing TGF-beta antibody. In conclusion, EGCs have profound antiproliferative effects on intestinal epithelial cells. Functional alterations in EGCs may therefore modify intestinal barrier functions and be involved in pathologies such as cancer or inflammatory bowel diseases.

Impedance-pH monitoring in proton pump inhibitor resistant patients: ready for clinical application?

Impedance‐pH monitoring represents a useful tool for studies and clinical research in oesophageal disorders, and may hold promise for the group of patients dissatisfied with their antireflux treatment

Antireflux surgery for non-erosive and erosive reflux disease in community practice

BACKGROUND

Antireflux surgery has been mainly evaluated in tertiary referral centres. Data regarding post-operative outcome in non-erosive reflux disease are lacking.

AIM

To assess long-term outcome after antireflux surgery performed in a community practice setting.

METHODS

We selected consecutively 60 non-erosive reflux disease patients and 61 erosive oesophagitis patients with symptomatic gastro-oesophageal reflux disease. After surgery, each subject answered a validated disease-specific health-related quality of life questionnaire and another questionnaire focusing on symptoms, late morbidity and drug use.

RESULTS

After a 43-month median follow-up, an excellent outcome was reported by less than two-thirds of patients. Quality of life scores were lower in the non-erosive reflux disease group, especially in female patients. Non-erosive reflux disease patients reported more daily symptoms and more reflux-related symptoms (P = 0.04). Proton-pump inhibitor use was higher in non-erosive reflux disease patients (P < 0.005). Multivariate analysis identified four independent predictive factors associated with better outcome, namely male gender, abnormal preoperative acid exposure, a long duration of symptoms and surgical expertise.

CONCLUSIONS

In community practice, the results of antireflux surgery are inferior to those reported by tertiary centres. Outcome seems poorer in non-erosive reflux disease especially in female patients. Nearly one-third of the non-erosive reflux disease patients continue to take proton-pump inhibitors. These results highlight the need for careful selection of patients before antireflux surgery.

Wireless capsule endoscopy versus ileocolonoscopy for the diagnosis of postoperative recurrence of Crohn's disease: a prospective study

BACKGROUND AND AIMS

Following ileocolonic resection for Crohn's disease (CD), early endoscopic recurrence predicts recurrence of symptoms. The aim of the study was to compare ileocolonoscopy and wireless capsule endoscopy (WCE) for the detection of postoperative recurrence in CD.

METHODS

WCE and ileocolonoscopy were performed within six months following surgery in 32 prospectively enrolled patients. Two independent observers interpreted the results of WCE. Recurrence in the neoterminal ileum was defined by a Rutgeerts score>or=1. When observers at WCE did not concur, WCE results were considered as either true negative or true positive and sensitivity and specificity were calculated according to both assumptions.

RESULTS

Recurrence occurred in 21 patients (68%) and was detected by ileocolonoscopy in 19 patients. Sensitivity was 90% and specificity 100%. Sensitivity of WCE was 62% and 76% and specificity was 100% and 90%, respectively, depending on assumptions. There was a correlation between the severity of the lesions measured by both methods (p<0.05). Lesions located outside the scope of conventional endoscopy were detected by WCE in two thirds of patients with excellent interobserver agreement (kappa>0.9) for all lesions with the exception of ulceration (kappa=0.7).

CONCLUSIONS

The sensitivity of WCE in detecting recurrence in the neoterminal ileum was inferior to that of ileocolonoscopy. In contrast, WCE detected lesions outside the scope of ileocolonoscopy in more than two thirds of patients. Additional follow up studies are needed to assess the clinical relevance of such lesions. At the present time, it seems that WCE cannot systematically replace ileocolonoscopy in the regular management of patients after surgery.

Changes in enteric neurone phenotype and intestinal functions in a transgenic mouse model of enteric glia disruption

AIMS

The influence of enteric glia on the regulation of intestinal functions is unknown. Our aim was to determine the phenotype of enteric neurones in a model of glia alterations and the putative changes in intestinal motility and permeability.

METHODS

Transgenic mice expressing haemagglutinin (HA) in glia were used. Glia disruption was induced by injection of activated HA specific CD8+ T cells. Control mice consisted of non-transgenic littermates injected with activated HA specific CD8+ T cells. Immunohistochemical staining for choline acetyltransferase (ChAT), substance P (SP), vasoactive intestinal peptide (VIP), and nitric oxide synthase (NOS) was performed on jejunal submucosal plexus (SMP) and myenteric plexus (MP). Neurally induced jejunal muscle activity was characterised in vitro. Gastrointestinal transit and paracellular permeability were measured using fluorescein isothiocyanate-dextran markers.

RESULTS

CD3 positive T cells infiltrates were observed in the MP of transgenic mice. In the SMP, the proportions of VIP and SP positive neurones decreased in transgenic mice compared with control mice. ChAT remained unchanged. In the MP, the proportions of ChAT and NOS positive neurones increased and decreased, respectively, in transgenic mice. In contrast, VIP and SP remained unchanged. Neurally mediated jejunal relaxation was lower in transgenic mice than in controls. This relaxation was reduced by NG-nitro-L-arginine methyl ester in control mice but not in transgenic mice. Gastrointestinal transit was delayed and intestinal permeability increased in transgenic mice compared with control mice.

CONCLUSION

Glia disruption induces changes in the neurochemical coding of enteric neurones, which may partly be responsible for dysfunctions in intestinal motility and permeability.

Resilience of the dominant human fecal microbiota upon short-course antibiotic challenge

Recent studies have shown that the human fecal microbiota is composed of a consortium of species specific to the host and resistant to modifications over time. Antibiotics are known to affect the intestinal microflora, and ensuing changes may result in antibiotic-associated diarrhea. It is therefore important to characterize the nature and amplitude of these modifications and the ability of this ecosystem to return to its original profile-i.e., its resilience. Six healthy volunteers received oral amoxicillin (1.5 g/day) for 5 days. Fecal samples were collected at day 0 (D0) before antibiotic treatment and at set intervals until 60 days thereafter. Fecal DNA was isolated, and V6-to-V8 regions of the 16S rRNA genes were amplified by PCR with general primers and analyzed by temporal temperature gradient gel electrophoresis. Dominant species profiles were compared on the basis of similarity (Pearson correlation coefficient). Dominant species profiles at D0 were used as a reference. The fecal microbiota showed a major shift in dominant species upon antibiotic treatment, starting 24 h after treatment initiation and reaching an average similarity of only 74% after 4 days. Within 30 days following antibiotic treatment, the fecal microbiota tended to reach an average similarity of 88% to the D0 value; within 60 days, the average similarity to the D0 value was 89%. However, in one subject, important modifications persisted for at least 2 months, with similarity to the D0 value remaining below 70%. We demonstrated the resilience of the dominant human fecal microbiota upon short-course antibiotic challenge. Yet the persistence of long-term alterations in some subjects may explain susceptibilities to antibiotic-associated diarrhea. Furthermore, these findings suggest that strategies reinforcing the ability of the fecal microbiota to resist modifications would be of clinical relevance.

Simultaneous recordings of oesophageal acid exposure with conventional pH monitoring and a wireless system (Bravo)

OBJECTIVES

Oesophageal pH monitoring is a useful test for the diagnosis of gastro-oesophageal reflux disease (GORD) but has some limitations related to the nasopharyngeal electrode. Recently, a telemetric catheter free system (CFS) (Bravo; Medtronic) was developed. The aim of this study was to determine the concordance of data between the conventional pH measurement system (CPHMS) and the CFS Bravo.

METHODS

Forty patients with symptoms suggestive of GORD underwent 24 hour oesophageal pH monitoring using the CPHMS with a nasopharyngeal electrode and the Bravo CFS simultaneously. The sensitive tips of both electrodes were positioned at the same level under fluoroscopy. In addition to automatic analysis, each reflux episode was checked visually and characterised.

RESULTS

There was a significant correlation (r = 0.87, p < 0.0001) between the 24 hour oesophageal acid exposures recorded by the CPHMS and the CFS. Twenty four hour oesophageal acid exposure was significantly lower with the CFS than with the CPHMS (2.4 (0.4-8.7) v 3.6 (0.7-8.6); p < 0.0001). Consequently, with the CFS, the cut off level for the diagnosis of GORD, as calculated from the regression equation, was 2.9% (for the 4.2% cut off determined in controls with the CPHMS). After this adjustment, concordance of the diagnosis of GORD was 88% (kappa 0.760). Diagnosis of GORD was established in more patients with the CFS 48 hour results than with the 24 hour results.

CONCLUSIONS

Despite strong correlations between oesophageal acid exposure recorded with the two devices, the Bravo CFS significantly under recorded acid exposure compared with the CPHMS. Provided some correcting factors are used, the Bravo CFS can improve the sensitivity of pHmetry for the diagnosis of GORD by allowing more prolonged recordings.

Review: what do we mean by GERD?--definition and diagnosis

Gastro-oesophageal reflux disease (GERD) is a condition in which the gastro-oesophageal reflux provokes symptoms or complications. Since the majority of patients with heartburn do not have mucosal breaks, expressions such as 'endoscopy-negative reflux disease' (ENRD), 'non-erosive reflux disease' (NERD), or even 'reflux-like dyspepsia' and 'functional heartburn' are frequently employed despite the lack of consensus concerning their exact meaning. Moreover, definition of a disease does not mean that precise diagnostic criteria exist. Diagnostic approaches to GERD differ considerably between primary and secondary care. The primary care physician's role is to decide, on the basis of symptoms and clinical examination, if it is likely that the patient has some serious problem which requires urgent investigation and intervention. In practice, a symptom-based diagnosis can often be made reliably because heartburn and regurgitation are very specific for GERD. The secondary care physician has to make a full evaluation of an already highly-selected patient and, as far as possible, to make a comprehensive, accurate diagnosis, using whatever investigative tools are required. However, there is no 'gold standard' for the diagnosis of GERD and 24-hour pH monitoring lacks sensitivity in NERD. Recently, impedance-pH monitoring has been introduced and promising results have been reported. However, this new technology needs further validation and technical improvement before being employed in routine clinical investigation.

A comparative study of the early effects of tenatoprazole 40 mg and esomeprazole 40 mg on intragastric pH in healthy volunteers

BACKGROUND

Tenatoprazole is a novel proton pump inhibitor with a seven-hour plasma half-life.

AIM

To compare the effects of tenatoprazole 40 mg and esomeprazole 40 mg on intragastric acidity during the first 48 h in healthy volunteers.

METHODS

This randomized two-period crossover study included 24 Helicobacter Pylori-negative subjects; tenatoprazole 40 mg or esomeprazole 40 mg daily were given before breakfast for two consecutive days, with a 2-week wash-out between the administration periods. Intragastric pH was monitored for 48 h.

RESULTS

Over 48 h, tenatoprazole 40 mg exerted a more potent acid inhibition than esomeprazole 40 mg (median pH: 4.3 vs. 3.9, P < 0.08; per cent of time above pH 4: 57% vs. 49%, P < 0.03; proportion of subjects with at least half of the time above pH 4: 71% vs. 46%). These differences resulted from better night-time acid control with tenatoprazole 40 mg than esomeprazole 40 mg (first night median pH: 4.2 vs. 2.9, P < 0.0001; second night: 4.5 vs. 3.2, P < 0.0001). The duration of nocturnal acid breakthroughs was significantly reduced during both nights. In contrast, no significant difference was detected during the daytime periods between both regimens.

CONCLUSION

Over the first 48 h, tenatoprazole 40 mg achieves a better overall and night-time control of gastric pH than esomeprazole 40 mg. The translation of better early control of acidity into clinical benefits deserves further studies.

Tenatoprazole, a novel proton pump inhibitor with a prolonged plasma half-life: effects on intragastric pH and comparison with esomeprazole in healthy volunteers

BACKGROUND

Proton pump inhibitors control gastric acidity better during the day than at night, when nocturnal acid breakthrough can occur. Tenatoprazole is a novel proton pump inhibitor with a seven-fold longer plasma half-life. Aim : To compare the effects of tenatoprazole 20 mg (T20), tenatoprazole 40 mg (T40) and esomeprazole 40 mg (E40) on intragastric acidity in healthy volunteers.

METHODS

This randomized, three-period, cross-over study enrolled 18 Helicobacter pylori-negative volunteers, who received E40, T20 and T40 once daily for 7 days with a 14-day washout between periods. Twenty-four-hour gastric pH monitoring was performed on day 7. Serum gastrin was assessed on day 8.

RESULTS

T40 induced a more potent acid inhibition than T20 (24-h median pH: 4.6 vs. 4.0, P < 0.01; daytime: 4.5 vs. 3.9, P < 0.01; night-time: 4.7 vs. 4.1, P < 0.05). T40 was more potent than E40 (24-h median pH: 4.6 vs. 4.2, P < 0.05; night-time: 4.7 vs. 3.6, P < 0.01); the pH > 4 holding time was higher during the night for T40 than for E40: 64.3% vs. 46.8%, P < 0.01; the nocturnal acid breakthrough duration was significantly shorter for T40 than for E40. No significant gastrin increase was observed and all drugs were well tolerated.

CONCLUSION

T40 is significantly more potent than T20 and E40 during the night. The therapeutic relevance of this pharmacological advantage deserves further study.

Neurochemical coding of myenteric neurones in the human gastric fundus

The major functions of the stomach are under the control of the enteric nervous system (ENS), but the neuronal circuits involved in this control are largely unknown in humans. Enteric neurones can be characterized by their neuromediator or marker content, i.e. by neurochemical coding. The purpose of this study was to characterize the presence and co-localization of neurotransmitters in myenteric neurones of the human gastric fundus. Choline acetyltransferase (ChAT), neurone-specific enolase (NSE), vasoactive intestinal polypeptide (VIP), nitric oxide synthase (NOS), substance P (SP) were detected by immunohistochemical methods in whole mounts of gastric fundus myenteric plexus (seven patients). Antibodies against ChAT and NOS labelled the majority of myenteric neurones identified by NSE (57.2 +/- 5.6% and 40.8 +/- 4.5%, respectively; mean +/- SD). The proportions of VIP- and SP-immunoreactive neurones were significantly smaller, constituting 19.6 +/- 6.9% and 16.0 +/- 3.7%, respectively. Co-localization studies revealed five major populations representing over 75% of the myenteric neurones: ChAT/-, 30.1 +/- 6.1%; NOS/-, 24.2 +/- 4.4%; ChAT/SP/-, 8.3 +/- 3.1%; NOS/VIP/-, 7.2 +/- 6.0%; ChAT/VIP/-, 4.9 +/- 2.6. Some similarities are apparent in the neurochemical coding of myenteric neurones in the stomach and intestine of humans, and between the stomach of humans and animals, but striking differences exist. The precise functional role of the neurochemically identified classes of neurones remains to be determined.

Toxin B of Clostridium difficile activates human VIP submucosal neurons, in part via an IL-1beta-dependent pathway

This study investigated whether toxin B of Clostridium difficile can activate human submucosal neurons and the involved pathways. Isolated segments of human colon were placed in organ culture for 3 h in the presence of toxin B or IL-1beta. Whole mounts of internal submucosal plexus were stained with antibodies against c-Fos, neuron-specific enolase (NSE), vasoactive intestinal polypeptide (VIP), and substance P (SP). The membrane potential (Vm) response of submucosal neurons to local application of toxin B and IL-1beta was determined by a multisite optical recording technique. Toxin B (0.1 to 10 ng/ml) increased the proportion of c-Fos-positive neurons dose dependently compared with the control. In the presence of toxin B (10 ng/ml), most c-Fos-positive neurons were immunoreactive for VIP (79.8 +/- 22.5%) but only 19.4 +/- 14.0% for SP. Toxin B induced a rapid rise in IL-1beta mRNA level and a sixfold increase in IL-1beta protein in supernatant after 3 h of incubation. c-Fos expression induced by toxin B was reduced dose dependently by IL-1 receptor antagonist (0.1-10 ng/ml). IL-1beta significantly increased c-Fos expression in submucosal neurons compared with the control (34.2 +/- 10.1 vs. 5.1 +/- 1.3% of NSE neurons). Microejection of toxin B had no effect on the Vm of enteric neurons. Evidence of a direct excitatory effect of IL-1beta on Vm was detected in a minority of enteric neurons. Therefore, toxin B of C. difficile activates VIP-positive submucosal neurons, at least in part, via an indirect IL-1beta-dependent pathway.

Molecular mechanisms involved in the antiproliferative effect of two COX-2 inhibitors, nimesulide and NS-398, on colorectal cancer cell lines

BACKGROUND

Cyclooxygenase (COX)-2 is up-regulated in most colorectal cancers. Chronic use of non-steroidal anti-inflammatory drugs, which target cyclooxygenases, have been shown to reduce the risk of these cancers. However, the mechanisms underlying this protective effect remain unclear.

AIMS

The aim of our study was to characterize the effects of two COX-2 selective inhibitors, NS-398 and nimesulide, on colorectal cancer cell proliferation, and to describe the molecular mechanisms involved.

MATERIALS AND METHODS

HT-29 and SW-1116 cell lines were cultured with either NS-398 or nimesulide. Cell proliferation was assessed by staining DNA with crystal violet. Cell cycle repartition and apoptosis were analysed by flow cytometry. The expression of COX-1 and COX-2. and of two cyclin dependent kinase inhibitors, p21Cip1 and p27Kip1, was analysed by Western blotting and RT-PCR.

RESULTS

Both drugs dose-dependently inhibited cell proliferation and induced G1 cell cycle blockade. HT-29 cells were more sensitive to both drugs than SW-1116 cells. p21Cip1 and p27Kip1 were induced on both cell lines. Concomitant induction of p21Cip1 mRNA indicates transcriptional modulation, whereas induction of p27Kip1 only at the protein level suggests post-translational modulation.

CONCLUSION

NS-398 and nimesulide inhibit colorectal cell proliferation through induction of p21Cip1 and p27Kip1.

RDP58, a novel immunomodulatory peptide with anti-inflammatory effects. A pharmacological study in trinitrobenzene sulphonic acid colitis and Crohn disease

BACKGROUND

Tumour necrosis factor (TNF) plays a key role in the pathogenesis of Crohn disease (CD). RDP58 is a novel anti-inflammatory decapeptide which was developed using a novel rational design strategy. Recently, RDP58 has proved to be a potent inhibitor of TNF production at a post-transcriptional step. The aims of this study were to investigate the anti-inflammatory properties of RDP58 ex vivo in human CD and in vivo in an experimental model colitis.

METHODS

Biopsies and lamina propria mononuclear cells from inflamed colonic mucosa of 18 CD patients were cultured for 24 h in the presence or absence of RDP58. TNF was quantified in a bioassay: interferon (IFN)-gamma and interleukin (IL)-1beta levels were measured by enzyme-linked immunosorbent assays. Colitis was induced by intra-rectal administration of 2, 4, 6 trinitrobenzene sulphonic acid (TNBS) in rats. Inflammation was assessed following 7 days of oral therapy with RDP58 or vehicle alone.

RESULTS

RDP58 led to decreased TNF and IFN-gamma (but not IL-1beta) production by biopsies and lamina propria mononuclear cells from CD patients. In rats with TNBS-induced colitis, oral RDP58 therapy reduced weight loss and diarrhoea and improved macroscopic and histological inflammation scores.

CONCLUSIONS

Our results suggest that RDP58 may be an effective therapy for CD with the clinical advantage of an oral administration.

Changes in chemical coding of myenteric neurones in ulcerative colitis

BACKGROUND

Morphological and functional changes in the enteric nervous system (ENS) have been reported in inflammatory bowel diseases but it is still uncertain whether neurochemical coding of myenteric neurones is altered in ulcerative colitis (UC).

AIMS

In this study we investigated transmitter co-localisation in myenteric neurones of normal colon and the colon of patients with UC.

METHODS

Choline acetyltransferase (ChAT), neurone specific enolase (NSE), vasoactive intestinal peptide (VIP), and substance P (SP) were detected by immunohistochemical methods in whole mounts of colonic myenteric plexus of UC patients (n=10) and controls (n=8).

RESULTS

The proportion of ChAT positive and VIP positive neurones relative to the NSE population did not differ in inflamed (33.3% and 9.3%, respectively) and non-inflamed segments (33.6% and 9.7%) of UC colon compared with controls (35.0% and 6.9%). The proportion of SP positive neurones was significantly larger in both inflamed (15.5%) and non-inflamed (20.3%) segments than in controls (5.9%). Analysis of changes in subpopulations showed that 26.9% of neurones were only ChAT positive in controls but that the proportion was significantly smaller in inflamed (18.8%) and non-inflamed (15.8%) areas of UC. The proportions of neurones containing ChAT and SP were significantly higher in inflamed (11.8%) and non-inflamed (13.9%) areas than in controls (5.0%).

CONCLUSION

Remodelling of myenteric neurones in UC involves a shift from mainly cholinergic to more SP positive innervation. This effect may constitute part of the neuronal basis for the motility disturbances observed in UC.

Percutaneous ethanol injection vs. resection in patients with small single hepatocellular carcinoma: a retrospective case-control study with cost analysis

BACKGROUND

Percutaneous ethanol injection and hepatic resection are the most widely used curative therapeutic options for patients with compensated liver disease and small hepatocellular carcinoma.

AIM

To compare percutaneous ethanol injection and hepatic resection in a selected group of consecutive French patients with a single hepatocellular carcinoma, smaller than or equal to 50 mm, in terms of survival, recurrence rate of malignancy and direct costs.

METHODS

The analysis of two contemporary cohorts of Child-Pugh A or B patients with a single hepatocellular carcinoma of < or = 50 mm treated by percutaneous ethanol injection (n=55) or hepatic resection (n=50).

RESULTS

Long-term survival was not significantly different between the two groups when the size of hepatocellular carcinoma was less than 30 mm. However, the survival of patients with hepatocellular carcinoma larger than 30 mm was higher after hepatic resection than after percutaneous ethanol injection (P=0.044). The cumulative direct costs were significantly higher in patients treated by hepatic resection than in those treated by percutaneous ethanol injection regardless of the tumour size. The calculated costs per month of survival in patients treated with percutaneous ethanol injection and hepatic resection were 999 vs. 3865 euros, respectively (P < 0.001).

CONCLUSIONS

Percutaneous ethanol injection is more cost effective than hepatic resection in patients with a single hepatocellular carcinoma smaller than 30 mm. However, in patients with a larger tumour, long-term survival is higher after hepatic resection.

Vasoactive intestinal peptide is involved in the inhibitory effect of interleukin-1 beta on the jejunal contractile response induced by acetylcholine

Although previous studies have shown that interleukin-1 beta (IL-1 beta) decreases acetylcholine (ACh)-induced intestinal contraction by an action on the enteric nervous system, the neuromediator(s) involved are still unknown.

AIM

To determine the role of nitric oxide (NO), vasoactive intestinal peptide (VIP) and/or adenosine triphosphate (ATP) in mediating this inhibitory effect.

METHODS

The effects of NO synthase inhibitors, VIP and ATP antagonists on motor response to the ACh were investigated before and after 90-min exposure of a rat preparation of jejunal longitudinal muscle-myenteric plexus to IL-1 beta. NG-nitro-L-arginine methyl ester, NG-nitro-L-arginine and NG-monomethyl-L-arginine were used to inhibit NO synthase, VIP (10-28) and [D-p-Cl-Phe6, Leu17] VIP to block VIP receptors, and suramin to block ATP receptors.

RESULTS

NO synthase inhibitors failed to block the inhibitory effect of IL-1 beta on ACh-contracted jejunum smooth muscle. Suramin also failed to affect IL-1 beta-induced inhibition, whereas VIP antagonists abolished it. Moreover, the action of IL-1 beta was partly reproduced by VIP.

CONCLUSIONS

While neither NO nor ATP accounts for the inhibitory effect of IL-1 beta on ACh-contracted jejunum, VIP seems to be a key-mediator of this effect.

Decreasing oesophageal acid exposure in patients with GERD: a comparison of rabeprazole and omeprazole

BACKGROUND

Rabeprazole has been shown to be more potent and faster than other proton pump inhibitors in in vitro studies and highly effective in decreasing oesophageal acid exposure in patients with gastro-oesophageal reflux disease (GERD).

AIM

This study was a multicentre, double-blind, placebo-controlled, randomized, parallel-group comparison of three active treatment regimens utilizing two different proton pump inhibitors, or placebo, administered over 7 days in patients with GERD.

METHODS

Eighty-two patients with symptomatic GERD were given placebo, rabeprazole 10 mg b.d., rabeprazole 20 mg o.m., or omeprazole 20 mg o.m. for 7 days. Twenty-four hour oesophageal pH monitoring was performed at baseline and repeated at the conclusion of the treatment period.

RESULTS

At the end of study, the percentage time (mean +/- s.d.) with pH < 4 over a 24-h period was significantly decreased by the three active regimens but without significant difference between them (9.27 +/- 4.77; 2.53 +/- 4.27; 2.02 +/- 1.71 and 2.91 +/- 4.06 for placebo, rabeprazole 10 mg b.d., rabeprazole 20 mg o.m. and omeprazole 20 mg o.m., respectively). Acid exposure was normalized in 90% of patients treated with rabeprazole 10 mg b.d., 95% treated with rabeprazole 20 mg o.m., 78% treated with omeprazole 20 mg o.m., and only 9.5% of patients treated with placebo. Both rabeprazole and omeprazole were well-tolerated.

CONCLUSIONS

Although rabeprazole 20 mg o.m. showed greater activity numerically, this study demonstrates that rabeprazole 10 mg b.d. and 20 mg o.m. are equivalent to omeprazole 20 mg o.m. in decreasing oesophageal acid exposure.

Review article: managing the dyspeptic patient--an interactive discussion

Dyspepsia, a common disorder, can present some difficult clinical dilemmas. Physicians should explore some of the more challenging cases of dyspepsia in a setting that fosters interactive dialogue among colleagues, as was the case at the interactive discussion reported below. A panel of experts presented and discussed three case histories. The audience was able to choose from among several options for diagnosis or treatment and recorded their votes by means of an electronic handset. The first case concerned the relationship between continued non-steroidal anti-inflammatory drug (NSAID) use and recurrent upper gastrointestinal (GI) symptoms without ulcer or Helicobacter pylori infection. The second was a woman with complex upper GI symptoms including heartburn. The last featured a young man with dyspepsia and no alarm symptoms. The first case showed that a standard dose of proton pump inhibitor (PPI) is the best treatment for patients with gastritis who continue to use NSAIDs. The second case revealed that 24-h pH monitoring can be used to establish a relationship between symptoms and reflux episodes. The third case demonstrated that it can be difficult to make a definitive diagnosis based on clinical symptoms, and that patients with endoscopy-negative reflux disease usually respond well to PPI therapy.

Projections of excitatory and inhibitory motor neurones to the circular and longitudinal muscle of the guinea pig colon

The aim of this study was to identify myenteric pathways to the circular and longitudinal muscle of the guinea pig proximal colon. To identify excitatory and inhibitory muscle motoneurones, we applied the neuronal retrograde tracer DiI onto the circular or longitudinal muscle layer and performed additional immunohistochemistry for nitric oxide synthase (NOS) and choline acetyltransferase (ChAT). On average 166 +/- 81 circular muscle motoneurones (CMMN) and 100 +/- 74 longitudinal muscle motoneurones (LMMN) were labelled by DiI tracing. Myenteric pathways innervating the muscle were either ascending (DiI-labelled neurones with oral projections) or descending (DiI-labelled neurones with anal projections). The circular muscle was preferentially innervated by ascending pathways (66.0 +/- 9.1%). Most ascending CMMN were ChAT-positive (87.2 +/- 8.5%), whereas descending CMMN were mainly NOS-positive (82.3 +/- 14.6%). Most ascending (62.2 +/- 11.1%) and descending (82.0 +/- 12.5%) CMMN had circumferential projection preferences (circumferential projections were longer than projections along the longitudinal gut axis). In contrast to the polarised projections to the circular muscle, the longitudinal muscle was equally innervated by ascending (46.2 +/- 15.1%) and descending (53.9 +/- 15.1%) neurones. Ascending and descending pathways to the longitudinal muscle consisted predominantly of ChAT-positive neurones (98.1 +/- 1.9% and 68.0 +/- 8.5%, respectively), and both pathways had prominent longitudinal projection preferences. Only 25.5% of the descending LMMN were NOS-positive. In conclusion, the circular muscle in the proximal colon is innervated by descending inhibitory (NOS-positive neurones) and ascending excitatory (ChAT-positive neurones) pathways. In contrast, the longitudinal muscle is primarily innervated by ascending and descending excitatory motoneurones, and only a small proportion of the descending pathway consisted of inhibitory motoneurones.

H. pylori and transient lower esophageal sphincter relaxations induced by gastric distension in healthy humans

The role of Helicobacter pylori infection in the control of lower esophageal sphincter (LES) motility, especially the occurrence of transient LES relaxations (TLESRs), was studied in eight H. pylori-positive and eight H. pylori-negative healthy subjects. During endoscopy, biopsy specimens were taken from the cardia, fundus, and antrum for determinations of H. pylori status, gastritis, and proinflammatory cytokine mucosal concentrations. LES motility was monitored during three different 30-min periods: baseline, gastric distension (barostat), and gastric distension with CCK infusion. Gastric distension significantly increased the TLESR rate, whereas CCK increased the rate of distension-induced TLESRs further and reduced resting LES pressure without significant differences between infected and noninfected subjects. H. pylori status did not influence resting LES pressure or gastric compliance. Cytokine mucosal concentrations were increased in infected patients, but no correlation was found with the TLESR rate, which was also independent of inflammation at the cardia, fundus, and antrum. These results suggest that H. pylori-associated inflammation does not affect the motor events involved in the pathogenesis of gastroesophageal reflux.

Interleukin-8 increases acetylcholine response of rat intestinal segments

BACKGROUND

Interleukin-8 (IL-8) is a pro-inflammatory cytokine highly expressed in inflammatory bowel diseases, but whose effects on intestinal motility are unknown.

AIM

To characterize the role of IL-8 in the contraction of rat intestinal segments.

METHODS

Contractile response to acetylcholine (ACh 10-6 M) in terminal ileal segments (including mucosa) from Wistar rats was measured before and after incubation (15, 30, 60 or 90 min) with IL-8 (1 ng/mL), and after 60 min of incubation with different doses of IL-8 (0, 0.1, 0.5, 1, 10 and 100 ng/mL). The effects of blocking neural transmission with tetrodotoxin (TTX) and inhibiting protein synthesis (cycloheximide) were tested. The contractile response of longitudinal muscle-myenteric plexus preparations (i.e. without mucosa) was measured after 60 min of incubation with 0.1 and 1 ng/mL of IL-8.

RESULTS

IL-8 increased ileal contraction induced by ACh 10(-6) M. This augmentation was significant after 60 min of incubation (58%, P=0.01) and persisted after 90 min (18%, P=0.04). A 60-min incubation period showed a dose-related effect, beginning at 0.5 ng/mL (30%, P=0.003) and reaching a peak at 1 ng/mL (58%, P=0.01). The same effect was also observed on colonic segments. TTX did not affect the IL-8 increase of ACh-induced contractions, which was completely abolished by cycloheximide. IL-8 had no significant effect on longitudinal muscle-myenteric plexus preparations.

CONCLUSION

In vitro, IL-8 increases contractile response of the ileum to ACh in a dose-dependent manner. This effect is not neurally mediated, but seems to involve protein synthesis by intestinal mucosa.

Proinflammatory role of leptin in experimental colitis in rats benefit of cholecystokinin-B antagonist and beta3-agonist

Leptin, a hormone primarily secreted from adipocytes, plays a key role in controlling body weight homeostasis. In vitro studies indicate that it is also implicated in immune responses. Hyperleptinaemia has been reported in acute inflammation, especially during the early stages of intestinal inflammation in rats. The present study investigated the possible role of leptin in the pathogenesis of trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats. Since no specific antagonist of leptin is available, a CCK-B antagonist (YM022) and a beta3 agonist (BRL37344) were used in this study to inhibit leptin secretion. Colitis was induced by intracolonic instillation of TNBS in rats. Five TNBS-groups were subcutaneously implanted with micropumps containing: placebo, YM022, BRL37344, BRL37344 and exogenous leptin simultaneously, or leptin alone. At sacrifices, colitis severity was assessed by macroscopic and histological scoring systems and by determination of tissue myeloperoxidase activity. The TNBS-induced hyperleptinaemia was significantly reduced by YM022 and BRL37344 (p<0.05). Inhibition of leptin secretion markedly reduced colonic inflammation, whatever the criteria considered (i.e. macroscopic, histological or biochemical). In contrast, administration of exogenous leptin completely abolished the beneficial effect of leptin-lowering drugs on colitis severity. These results provide the first direct evidence for an important deleterious role of leptin in the pathogenesis of experimental intestinal inflammation and suggest that a pro-inflammatory activity is attributable to leptin in vivo. Further studies are required to determine if these results have clinical significance.

Endoscopy-negative reflux disease

Endoscopy-negative reflux disease (ENRD) is more prevalent than reflux esophagitis, especially in a primary care setting. Acid-sensitive esophagus (ie, reflux-related symptoms with normal acid exposure at 24-hour pH monitoring) is part of the gastroesophageal reflux disease spectrum. ENRD is not a mild disease (symptoms return frequently and have an impact on quality of life), but it rarely progresses to the erosive stage. In patients with atypical or extra-esophageal manifestations, pH monitoring remains useful, and symptom analysis (symptom index or symptom-associated probability) is of pivotal importance. A proton pump inhibitor (PPI) test may represent a cost-effective alternative to 24-hour pH monitoring. However, well-designed validation studies are necessary to assess the diagnostic value of PPI tests and improve specificity without reducing sensitivity. Management of ENRD is based on the same principles as that of reflux esophagitis. Restoration of quality of life is the major goal. Proton pump inhibitors are not more (and are sometimes even less) effective in non-erosive reflux disease than in reflux esophagitis. Different long-term strategies (continuous maintenance, intermittent or on-demand therapy) are available, depending on the needs of the patient. Antireflux surgery may be indicated in carefully selected patients. In the future, pharmacologic approaches targeted to transient lower esophageal sphincter relaxation or visceral perception should be developed.

[Acid-sensitive esophagus: natural history and effect on the quality of life. Comparison with gastroesophageal reflux]

The acid hypersensitive esophagus (AHE) is characterized by a normal esophageal acid exposure but a significant association between symptoms and reflux episodes. The natural history of AHE remains poorly known. We therefore conducted a follow-up study to compare the initial presentation and natural history of AHE and classical GERD. Quality of life (QOL) was also assessed.

PATIENTS AND METHODS

Two groups of patients referred to our laboratory for 24-hour pH-monitoring (between 1991 and 1996) were compared. Group 1 consisted of 127 consecutive patients with AHE. Group 2 consisted of 101 patients with GERD. All patients were invited by mail to fill-in two questionnaires, the first concerning clinical course and therapeutic needs and the second QOL (questionnaire Reflux-Qual). Finally 62% and 59% of group 1 and 2 respectively did respond to both questionnaires. The corresponding follow-up periods were 4.1 and 4.3 years, respectively.

RESULTS

The two groups did not differ at initial presentation with regard to age, sex, symptoms prevalence and severity of esophagitis (80% of group 1 and 75% of group 2 were endoscopy-negative patients). At an average follow-up of 4 years symptoms persisted in 80% and 71% of patients respectively. Seventy five per cent of patients in both groups continued to take antireflux drugs. QOL scores were similarly reduced in both groups (71 +/- 26 vs 70 +/- 27).

CONCLUSIONS

The initial presentation and clinical outcome of AHE and GERD are similar. QOL is notably impaired and the majority of patients continue to receive antireflux medications.

Butyrate inhibits inflammatory responses through NFkappaB inhibition: implications for Crohn's disease

BACKGROUND/AIM

Proinflammatory cytokines are key factors in the pathogenesis of Crohn's disease (CD). Activation of nuclear factor kappa B (NFkappaB), which is involved in their gene transcription, is increased in the intestinal mucosa of CD patients. As butyrate enemas may be beneficial in treating colonic inflammation, we investigated if butyrate promotes this effect by acting on proinflammatory cytokine expression.

METHODS

Intestinal biopsy specimens, isolated lamina propria cells (LPMC), and peripheral blood mononuclear cells (PBMC) were cultured with or without butyrate for assessment of secretion of tumour necrosis factor (TNF) and mRNA levels. NFkappaB p65 activation was determined by immunofluorescence and gene reporter experiments. Levels of NFkappaB inhibitory protein (IkappaBalpha) were analysed by western blotting. The in vivo efficacy of butyrate was assessed in rats with trinitrobenzene sulphonic acid (TNBS) induced colitis.

RESULTS

Butyrate decreased TNF production and proinflammatory cytokine mRNA expression by intestinal biopsies and LPMC from CD patients. Butyrate abolished lipopolysaccharide (LPS) induced expression of cytokines by PBMC and transmigration of NFkappaB from the cytoplasm to the nucleus. LPS induced NFkappaB transcriptional activity was decreased by butyrate while IkappaBalpha levels were stable. Butyrate treatment also improved TNBS induced colitis.

CONCLUSIONS

Butyrate decreases proinflammatory cytokine expression via inhibition of NFkappaB activation and IkappaBalpha degradation. These anti-inflammatory properties provide a rationale for assessing butyrate in the treatment of CD.

Relationships between transit time in man and in vitro fermentation of dietary fiber by fecal bacteria

OBJECTIVE

To assess the effects of drug-induced changes in mean transit time (MTT) on the activity of human fecal flora in vitro.

METHODS

The activity of fecal flora was estimated by the ability of a fecal inoculum to ferment a substrate (beet fiber) in vitro in a batch system for 24 h. The inoculum was collected from 8 healthy volunteers studied during three 3-week randomized periods, who received a controlled diet alone (control period) or the same diet with either cisapride or loperamide. Cisapride and loperamide were adjusted in order to halve and double MTT measured during the control period. At the end of each period, the percentage disappearance of the initial added substrate and the concentration and the profile of short-chain fatty acids (SCFAs), were determined.

RESULTS

In the control period, the pH of the inoculum and SCFA concentration were inversely related to MTT (P=0.0001). Individual SCFA production was also significantly related to MTT (P<0.01). Cisapride-reduced transit time was associated with a significant rise in the concentrations of total SCFAs (P<0.05), propionic and butyric acids (P<0.05) and the percentage substrate disappearance (P<0.05). Inverse relations were observed during the loperamide period. Moreover, MTT was inversely related to the percentage substrate disappearance (P<0.001), SCFA production (P<0.001) and butyrate production (P<0.0005).

CONCLUSION

Changes in MTT alter bacterial activity and modify the bacterial pathways affecting the proportion of individual SCFAs. European Journal of Clinical Nutrition (2000) 54, 603-609

Short-chain fatty acids induce cytoskeletal and extracellular protein modifications associated with modulation of proliferation on primary culture of rat intestinal smooth muscle cells

Short-chain fatty acids are the main end products of bacterial fermentation of carbohydrates. Their role on the metabolism and biology of colonocytes is now well characterized. However, the functional consequences of their presence on intestinal smooth muscle cells remain poorly studied. We aimed to assess the effect of different short-chain fatty acids on ileal and colonic smooth muscle cells in primary culture and on A7R5 line. Butyrate (above 0.1 mM) inhibited A7R5 cell proliferation, while at low concentration (0.05 to 0.5 mM) butyrate significantly stimulated the proliferation of ileal and colonic myocytes in primary culture. An inhibition was observed at higher concentrations. Collagenous and noncollagenous protein synthesis was stimulated by butyrate. Moreover, butyrate stimulated actin and myosin expression. Thus, butyrate, which is produced by dietary fiber fermentation, may affect intestinal muscles by directly acting at the molecular level on myocytes.

How do we offer clinical relief to patients with gastro-oesophageal reflux disease?

In gastro-oesophageal reflux disease (GORD), the majority of patients are endoscopy negative. However, symptoms can affect the quality of life irrespective of the presence of oesophagitis. Proton pump inhibitors (PPIs) are far more effective than H2 receptor antagonists (H2RAs) or prokinetics with regard to the speed of symptom relief. Despite this undisputed progress, there is some conflict on whether symptoms should be managed until full resolution in endoscopy-negative patients or in those with mild oesophagitis. Considering that GORD is not a life-threatening condition, some authorities admit that patients should accept minimal residual symptoms. They argue that PPIs are expensive while healthcare resources are limited, and that long-term safety of PPIs has not been completely established. Moreover, they underline that many patients do not seek medical help and are satisfied with self-medication (with antacids/alginates or even over-the-counter H2RAs). On the other hand, some clinicians prefer a full resolution of symptom strategy because this is now achievable with modern PPIs without serious concerns in terms of tolerance and safety. Indeed, quality of life is rapidly restored by PPIs. Moreover, symptom relief by PPIs is highly predictive of healing, making endoscopic control unnecessary at least for mild/moderate oesophagitis. Finally, there is also some controversy over whether we should start treatment with PPIs or use less potent drugs as first-line therapy. If one considers not only the direct cost of drugs, but also the indirect ones (e.g. sick leave days), it is reasonable to think that PPIs may be more cost-effective than H2RAs or prokinetics, at least when the disease is of moderate or severe intensity. In conclusion, with modern PPIs like lansoprazole, rapid and full resolution of symptoms is now achievable in the large majority of patients.

Isosorbide mononitrate and propranolol compared with propranolol alone for the prevention of variceal rebleeding

The aim of this study was to test the effectiveness of isosorbide-5-mononitrate (IM) as an adjunct to propranolol (PR) in the prevention of variceal rebleeding. Ninety-five cirrhotic patients with variceal bleeding were randomly assigned to treatment with PR + IM (46 patients) or PR alone (49 patients). Eighteen patients in the PR + IM group and 28 in the PR group had rebleeding during the 2 years after randomization. The actuarial probability of rebleeding 2 years after randomization was lower in the PR + IM group (40.4% vs. 57.4%) but the difference was not significant (P =. 09). However, the decrease in the risk of rebleeding reached statistical significance after stratification according to age, i.e. less than 50 versus >/=50 years old, (P =.03) or by adding an additional year of follow-up (P =.05). No significant difference was found in rebleeding index and survival. The multivariate Cox analysis indicated first, that both treatment (P =.03) and age (P =. 001) were factors predictive of rebleeding and second, that PR + MI reduced the risk of rebleeding by half (relative risk: 0.51, 95% confidence interval: 0.28-0.95). Seven patients in the PR + MI group and 1 patient in the PR group had to discontinue one of the drugs because of adverse events (P =.03). These results suggest that the addition of IM improves the efficacy of PR alone in the prevention of variceal rebleeding in cirrhotic patients. However no beneficial effects were observed on other parameters reflecting the efficacy of treatment.

Does the route of feeding modify gastric emptying in rats?

BACKGROUND

It has been shown that the pattern of previous nutrient intake can influence gastric emptying. However, the effect of the absence of enteral stimulation in the setting of a normal energy supply on gastric emptying has not been examined. The aim of this study was to determine whether the absence of enteral stimulation during total parenteral nutrition (TPN) could modify gastric emptying in rats.

METHODS

Two experiments were performed. First, gastric emptying of a peptone meal was compared between rats receiving TPN, oral liquid diet (same solution as TPN), or regular diet (control group) for 10 days. In the second experiment, gastric emptying of two test meals (40% peptone and 25% glucose) was studied before and after rats received TPN or intragastric nutrition (same solution as TPN) for 10 to 12 days.

RESULTS

In experiment 1, gastric emptying of 40% peptone in the TPN and liquid diet groups was slower than that in the control group. This difference was significant between the TPN group and the control group (p < .01) but not between the liquid diet and control groups (p = .076). Gastric emptying of this meal in the TPN and liquid diet groups was similar. In experiment 2, no difference in gastric emptying of 40% peptone or 25% glucose was found between rats receiving TPN and those receiving intragastric nutrition for 10 to 12 days.

CONCLUSIONS

The composition of diet not the route of feeding is important in the modification of gastric emptying by the pattern of previous nutrient intake.

Modulation by colonic fermentation of LES function in humans

Colonic fermentation of carbohydrate has been shown to influence gastric and intestinal motility. Our aim was to investigate the effects of colonic infusion of lactose and short-chain fatty acids (SCFAs) on lower esophageal sphincter (LES) function in humans. LES pressure (LESP), transient relaxations of LES (TLESRs), and esophageal pH were monitored over 6 h on 4 different days in 7 healthy volunteers. After 1 h of baseline recording, the effects of different colonic infusions (270 ml of isotonic or hypertonic saline, 30 g lactose, or 135 mmol SCFAs) were tested in fasting conditions and after a standard meal. Peptide YY (PYY) and oxyntomodulin (OLI) were also measured in plasma. Both lactose and SCFA infusions increased the number of TLESRs as well as the proportion of TLESRs associated with acid reflux episodes, but saline solutions did not. The postprandial fall of LESP was enhanced by previous SCFA infusion. Plasma PYY and OLI increased similarly after all colonic infusions. Colonic fermentation of lactose markedly affected LES function, and this effect was reproduced by SCFA infusion. Whether the mechanisms of this feedback phenomenon are of hormonal nature, neural nature, or both remains to be determined.

Butyrate and trichostatin A effects on the proliferation/differentiation of human intestinal epithelial cells: induction of cyclin D3 and p21 expression

BACKGROUND

Sodium butyrate, a product of colonic bacterial fermentation, is able to inhibit cell proliferation and to stimulate cell differentiation of colonic epithelial cell lines. It has been proposed that these cellular effects could be linked to its ability to cause hyperacetylation of histone through the inhibition of histone deacetylase.

AIM

To analyse the molecular mechanisms of butyrate action on cell proliferation/differentiation and to compare them with those of trichostatin A, a well known inhibitor of histone deacetylase.

METHODS

HT-29 cells were grown in the absence or presence of butyrate or trichostatin A. Cell proliferation and cell cycle distribution were studied after DNA staining by crystal violet and propidium iodide respectively. Cell cycle regulatory proteins were studied by western blot and reverse transcription-polymerase chain reaction. Cell differentiation was followed by measuring brush border enzyme activities. Histone acetylation was studied by acid/urea/Triton acrylamide gel electrophoresis.

RESULTS

Butyrate blocked cells mainly in the G(1) phase of the cell cycle, whereas trichostatin A was inhibitory in both G(1) and G(2) phases. Butyrate inhibited the mRNA expression of cyclin D1 without affecting its protein expression and stimulated the protein expression of cyclin D3 without affecting its mRNA expression. Trichostatin A showed similar effects on cyclin D1 and D3. Butyrate and trichostatin A stimulated p21 expression both at the mRNA and protein levels, whereas their effects on the expression of cyclin dependent kinases were slightly different. Moreover, butyrate strongly stimulated the activity of alkaline phosphatase and dipeptidyl peptidase IV, whereas trichostatin A had no effect. Finally, a six hour exposure to butyrate or trichostatin A induced histone H4 hyperacetylation. At 15 and 24 hours, histone H4 remained hyperacetylated in the presence of butyrate, whereas it returned to control levels in the presence of trichostatin A.

CONCLUSIONS

The data may explain how butyrate acts on cell proliferation/differentiation, and they show that trichostatin A does not reproduce every effect of butyrate, mainly because of its shorter half life.

Pathways and receptors involved in peptide YY induced contraction of rat proximal colonic muscle in vitro

BACKGROUND

Peptide YY (PYY) is involved in the regulation of several gut functions, including secretion and motility. It exerts its effects through a family of six receptors, commonly named the Y receptor family.

AIMS

To characterise the effects of PYY on strips of rat proximal colon in vitro, and to determine the pathways and receptors involved.

METHODS

Contractions of strips removed from the muscle layer of rat proximal colon were recorded under isometric conditions, using PYY, Y receptor agonists and antagonists, and nerve blockers. Reverse transcription-polymerase chain reaction was also performed to detect the presence of mRNA coding for Y receptors. Finally, smooth muscle cells were isolated to estimate the cell length and intracellular Ca(2+) concentration in the presence and absence of PYY.

RESULTS

PYY, neuropeptide Y (NPY), pancreatic polypeptide (PP) and [Leu31,Pro34]NPY induced a dose dependent contraction of strips from proximal colon. Tetrodotoxin partially inhibited the PYY and NPY induced contractions, and strongly inhibited the PP induced contraction. Specific antagonists showed the involvement of cholinergic nicotinic receptors and NK1 receptor. BIBP 3226, a specific Y1 antagonist, did not modify the colonic smooth muscle response to PYY, whereas blocking L-type Ca(2+) channels with D-600 abolished its effects. Moreover, PYY induced an increase in intracellular Ca(2+) concentration, associated with a reduction in cell length. mRNA encoding Y1 and Y4 receptors were detected in the muscle strips.

CONCLUSIONS

These findings suggest that PYY stimulates colonic contractile activity in vitro through (a) a nervous Y4 dependent pathway and (b) a pathway involving a potential new receptor on myocytes.