Healthy controls have as much bile reflux as gastric ulcer patients

Gastroparesis Worsens Indomethacin-Induced Gastric Antral Ulcers by Bile Reflux via Activation of 5-HT3 and Dopamine D2 Receptors in Mice

BACKGROUND/AIMS

We examined the contributions of gastric emptying and duodenogastric bile reflux in the formation of gastric antral ulcers induced by NSAIDs in mice.

METHODS

We used the murine re-fed indomethacin (IND) experimental ulcer model. Outcome measures included the appearance of gastric lesions 24 h after IND treatment and the assessment of gastric contents and the concentration of bile acids 1.5 h after re-feeding. The effects of atropine, dopamine, SR57227 (5-HT3 receptor agonist), apomorphine, ondansetron, haloperidol, and dietary taurocholate and cholestyramine were also examined.

RESULTS

IND (10 mg/kg, s.c.) induced severe lesions only in the gastric antrum in the re-fed model. The antral lesion index and the amount of food intake during the 2-h refeeding period were positively correlated. Atropine and dopamine delayed gastric emptying, increased bile reflux, and worsened IND-induced antral lesions. SR57227 and apomorphine worsened antral lesions with increased bile reflux. These effects were prevented by the anti-emetic drugs ondansetron and haloperidol, respectively. The anti-emetic drugs markedly decreased the severity of antral lesions and the increase of bile reflux induced by atropine or dopamine without affecting delayed gastric emptying. Antral lesions induced by IND were increased by dietary taurocholate but decreased by the addition of the bile acid sequestrant cholestyramine.

CONCLUSIONS

These results suggest that gastroparesis induced by atropine or dopamine worsens NSAID-induced gastric antral ulcers by increasing duodenogastric bile reflux via activation of 5-HT3 and dopamine D2 receptors.

Laparoscopic One-Anastomosis Gastric Bypass: Technique, Results, and Long-Term Follow-Up in 1200 Patients

BACKGROUND

Excellent results have been reported with mini-gastric bypass. We adopted and modified the one-anastomosis gastric bypass (OAGB) concept. Herein is our approach, results, and long-term follow-up (FU).

METHODS

Initial 1200 patients submitted to laparoscopic OAGB between 2002 and 2008 were analyzed after a 6-12-year FU. Mean age was 43 years (12-74) and body mass index (BMI) 46 kg/m2 (33-86). There were 697 (58 %) without previous or simultaneous abdominal operations, 273 (23 %) with previous, 203 (17 %) with simultaneous, and 27 (2 %) performed as revisions.

RESULTS

Mean operating time (min) was as follows: (a) primary procedure, 86 (45-180); (b) with other operations, 112 (95-230); and (c) revisions, 180 (130-240). Intraoperative complications led to 4 (0.3 %) conversions. Complications prompted operations in 16 (1.3 %) and were solved conservatively in 12 (1 %). Long-term complications occurred in 12 (1 %). There were 2 (0.16 %) deaths. Thirty-day and late readmission rates were 0.8 and 1 %. Cumulative FU was 87 and 70 % at 6 and 12 years. The highest mean percent excess weight loss was 88 % (at 2 years), then 77 and 70 %, 6 and 12 years postoperatively. Mean BMI (kg/m2) decreased from 46 to 26.6 and was 28.5 and 29.9 at those time frames. Remission or improvement of comorbidities was achieved in most patients. The quality of life index was satisfactory in all parameters from 6 months onwards.

CONCLUSIONS

Laparoscopic OAGB is safe and effective. It reduces difficulty, operating time, and early and late complications of Roux-en-Y gastric bypass. Long-term weight loss, resolution of comorbidities, and degree of satisfaction are similar to results obtained with more aggressive and complex techniques. It is currently a robust and powerful alternative in bariatric surgery.

A weakly acidic solution containing deoxycholic acid induces esophageal epithelial apoptosis and impairs integrity in an in vivo perfusion rabbit model

Impaired esophageal mucosal integrity may be an important contributor in the pathophysiology of gastroesophageal reflux disease (GERD). Nevertheless, the effect of potentially harmful agents on epithelial integrity is mainly evaluated in vitro for a short period of time and the possible induction of epithelial apoptosis has been neglected. Our objective was to assess the effect of an acidic and weakly acidic solution containing deoxycholic acid (DCA) on the esophageal epithelium in an in vivo rabbit model of esophageal perfusion and to evaluate the role of the epithelial apoptosis. The esophagus of 55 anesthetized rabbits was perfused for 30 min with different solutions at pH 7.2, pH 5.0, pH 1.0, and pH 5.0 containing 200 and 500 μM DCA. Thereafter, animals were euthanized immediately or at 24 or 48 h after the perfusion. Transepithelial electrical resistance, epithelial dilated intercellular spaces, and apoptosis were assessed in Ussing chambers, by transmission electron microscopy, and by TUNEL staining, respectively. No macroscopic or major microscopic alterations were observed after the esophageal perfusions. The acidic and weakly acidic solution containing DCA induced similar long-lasting functional impairment of the epithelial integrity but different ultrastructural morphological changes. Only the solution containing DCA induced epithelial apoptosis in vivo and in vitro in rabbit and human tissue. In contrast to acid, a weakly acidic solution containing DCA induces epithelial apoptosis and a long-lasting impaired mucosal integrity. The presence of apoptotic cells in the esophageal epithelium may be used as a marker of impaired integrity and/or bile reflux exposure.

Systematic review: bile acids and intestinal inflammation-luminal aggressors or regulators of mucosal defence?

BACKGROUND

Inflammatory bowel diseases (IBD), comprising Crohn's disease and ulcerative colitis (UC), are chronic conditions attributed to an aberrant immune response to luminal triggers. Recently, published work suggests a pathogenic role for bile acids in this context.

AIM

To perform a systematic review of studies investigating the role of bile acids in intestinal inflammation and present potentially relevant clinical implications.

METHODS

Pubmed search for English language articles published up to May 2015. Terms used were: 'bile', 'bile acid', 'barrier', 'small bowel injury', 'Crohn's' and 'colitis'.

RESULTS

Experimental studies support a variable role for bile acids in intestinal barrier homoeostasis. This may be attributed to different physicochemical properties, variable effects on epithelia and immune cells via bile acids-specific receptors, or through a cross-talk with the gut microbiome. A reduction in the bile acids pool, with lower concentrations of secondary forms, has been recognised for some time in Crohn's disease and associated to ileal dysfunction and bile acids malabsorption. Recent work suggests that these changes, including an increase in sulphated forms, are related to inflammatory activity in both Crohn's disease and UC. The detrimental effects of 'western diet' elements such as emulsifiers and fat, which have been implicated in the development of the current IBD and obesity epidemics, may also be bile acid-mediated.

CONCLUSIONS

Although there are only a few observational clinical studies to support an interaction, in vivo human and animal studies support an association between bile acids metabolism, the gut microbiome and intestinal inflammation. This may well prove to have significant diagnostic and therapeutic implications.

Controversy surrounding 'mini' gastric bypass

Mini gastric bypass is a modification of Mason loop gastric bypass with a longer lesser curvature-based pouch. Though it has been around for more than 15 years, its uptake by the bariatric community has been relatively slow, and the procedure has been mired in controversy right from its early days. Lately, there seems to be a surge in the interest in this procedure, and there is now published experience with more than 5,000 procedures globally. This review examines the major controversial aspects of this procedure against the available scientific literature. Surgeons performing this procedure need to be aware of these controversies and counsel their patients appropriately.

Esophageal barrier function and tight junction expression in healthy subjects and patients with gastroesophageal reflux disease: functionality of esophageal mucosa exposed to bile salt and trypsin in vitro

BACKGROUND AND AIMS. Gastroesophageal reflux disease (GERD) is associated with impaired epithelial barrier function. However, the influence of acid and/or bile acids on human esophageal epithelial barrier function and the tight junction (TJ) proteins has not been fully elucidated. The aim of the study is to investigate the esophageal barrier function and TJ expression in healthy subjects and patients with GERD. The functionality of esophageal mucosa exposed to bile salt deoxycholic acid (DCA) and trypsin has been studied in vitro. MATERIAL AND METHODS. Endoscopic biopsies from healthy controls and patients with GERD-related symptom with endoscopic erosive signs, as well as esophageal mucosa taken from patients undergoing esophagectomy were evaluated in Ussing chambers and by western blot and immunohistochemistry. RESULTS. The esophageal epithelium from GERD patients had lower electrical resistance and higher epithelial currents than controls. Claudin-1 and -4 were significantly decreased in GERD patients. The bile salt DCA in the low concentration of 1.5 mM and trypsin increased the resistance and claudin-1 expression, while the higher concentration of 2.5 mM DCA and trypsin decreased the resistance and the claudin-3, -4 and E-cadherin expressions. CONCLUSION. In addition to acidic reflux, duodenal reflux components, such as bile salts and trypsin, have the potential to disrupt the esophageal barrier function, partly by modulating the TJ proteins. However, the expression of TJ is dependent on both the refluxed material as well as the concentration of the bile salt.

Assessment and protection of esophageal mucosal integrity in patients with heartburn without esophagitis

OBJECTIVES

Intact esophageal mucosal integrity is essential to prevent symptoms during gastroesophageal reflux events. Approximately 70% of patients with heartburn have macroscopically normal esophageal mucosa. In patients with heartburn, persistent functional impairment of esophageal mucosal barrier integrity may underlie remaining symptoms. Topical protection of a functionally vulnerable mucosa may be an attractive therapeutic strategy. We aimed to evaluate esophageal mucosal functional integrity in patients with heartburn without esophagitis, and test the feasibility of an alginate-based topical mucosal protection.

METHODS

Three distal esophageal biopsies were obtained from 22 patients with heartburn symptoms, and 22 control subjects. In mini-Ussing chambers, the change in transepithelial electrical resistance (TER) of biopsies when exposed to neutral, weakly acidic, and acidic solutions was measured. The experiment was repeated in a further 10 patients after pretreatment of biopsies with sodium alginate, viscous control, or liquid control "protectant" solutions.

RESULTS

Biopsy exposure to neutral solution caused no change in TER. Exposure to weakly acidic and acidic solutions caused a greater reduction in TER in patients than in controls (weakly acid -7.2% (95% confidence interval (CI) -9.9 to -4.5) vs. 3.2% (-2.2 to 8.6), P<0.05; acidic -22.8% (-31.4 to 14.1) vs. -9.4% (-17.2 to -1.6), P<0.01). Topical pretreatment with alginate but not with control solutions prevented the acid-induced decrease in TER (-1% (-5.9 to 3.9) vs. -13.5 (-24.1 to -3.0) vs. -13.2 (-21.7 to -4.8), P<0.05).

CONCLUSIONS

Esophageal mucosa in patients with heartburn without esophagitis shows distinct vulnerability to acid and weakly acidic exposures. Experiments in vitro suggest that such vulnerable mucosa may be protected by application of an alginate-containing topical solution.

Relation between reflux of bile acids into the stomach and gastric mucosal atrophy, intestinal metaplasia in biopsy specimens

During endoscopic examinations we collected fluid in the stomach that included reflux fluid from the duodenum, and assessed the effect of quantitatively determined bile acids on glandular atrophy and intestinal metaplasia using biopsy specimens. A total of 294 outpatients were enrolled in this study. Total bile acid concentration was measured by an enzyme immunoassay. Glandular atrophy and intestinal metaplasia scores were graded according to the Updated Sydney System. An effect of refluxed bile acids on atrophy and intestinal metaplasia was shown in the high-concentration reflux group in comparison with the control group. However, when the odds ratios (ORs) were calculated according to whether Helicobacter pylori (H. pylori) infection was present, no significant associations were shown between reflux bile acids and atrophy in either the H. pylori-positive cases or -negative cases. The same was true for intestinal metaplasia in the H. pylori-positive cases, whereas intestinal metaplasia was more pronounced in the high-concentration reflux group in the H. pylori-negative cases (OR 2.4, 95%CI 1.1–5.6). We could not clarify the effect of the reflux of bile acids into the stomach in the progression of atrophy. High-concentration bile acids had an effect on the progression of intestinal metaplasia in the H. pylori-negative cases.

Divalent minerals decrease micellarization and uptake of carotenoids and digestion products into Caco-2 cells

Carotenoids are lipophilic, dietary antioxidants with the potential to prevent chronic and age-related diseases. Prior to their availability for physiological functions, carotenoids require micellarization and intestinal uptake, both constituting marginally understood processes. Based on an in vitro digestion model coupled to Caco-2 cells, we assessed the effect of dietary abundant divalent ions on spinach-derived carotenoid micellarization and cellular uptake: Ca and Mg ranging from 7.5 to 25 mmol/L in the digesta and Zn and Fe ranging from 3.8 to 12.5 mmol/L. Both micellarization and uptake were significantly inhibited by minerals in a concentration-dependent manner, with stronger effects for Fe and Zn compared to Ca and Mg. Compared to controls (no mineral addition), fractional micellarization and uptake were decreased to the greatest extent (to 22.5 and 5.0%, respectively; P < 0.001) by 12.5 mmol/L Fe. Effects of Mg were of the least magnitude; at 25 mmol/L, only uptake was decreased significantly to 69.2% of the control value (P < 0.001). Total cellular carotenoid uptake from test meals decreased similarly compared to micellarization; however, decreased β-carotene micellarization was counterbalanced by improved fractional cellular uptakes from the micelles for all ions. Compared to controls, fractional β-carotene uptake from the micelles was greater in samples digested in the presence of Fe, Ca, and Zn, by up to 5-10 times at the highest concentrations of each ion (P < 0.001). Like for the above carotenoids, a high cellular uptake of the epoxycarotenoid conversion products neochrome (from neoxanthin) and luteoxanthin+auroxanthin (from violaxanthin) was also observed. The present results indicate that divalent ions may inhibit carotenoid micellarization and uptake.

Role of the HefC efflux pump in Helicobacter pylori cholesterol-dependent resistance to ceragenins and bile salts

The human gastric pathogen Helicobacter pylori modifies host cholesterol via glycosylation and incorporates the glycosylated cholesterol into its membrane; however, the benefits of cholesterol to H. pylori are largely unknown. We speculated that cholesterol in the H. pylori membrane might alter the susceptibility of these organisms to membrane-disrupting antibacterial compounds. To test this hypothesis, H. pylori strains were cultured in Ham's F-12 chemically defined medium in the presence or absence of cholesterol. The two cultures were subjected to overnight incubations with serial 2-fold dilutions of 10 bile salts and four ceragenins, which are novel bile salt derivatives that mimic membrane-disrupting activity of antimicrobial peptides. H. pylori cultured with cholesterol was substantially more resistant to seven of the bile salts and three ceragenins than H. pylori cultured without cholesterol. In most cases, these cholesterol-dependent differences ranged from 2 to 7 orders of magnitude; this magnitude depended on concentration of the agent. Cholesterol is modified by glycosylation using Cgt, a cholesteryl glycosyltransferase. Surprisingly, a cgt knockout strain still maintained cholesterol-dependent resistance to bile salts and ceragenins, indicating that cholesterol modification was not involved in resistance. We then tested whether three putative, paralogous inner membrane efflux pumps, HefC, HefF, or HefI, played a role. While HefF and HefI appeared unimportant, HefC was shown to play a critical role in the resistance to bile salts and ceragenins by multiple methods in multiple strain backgrounds. Thus, both cholesterol and the putative bile salt efflux pump HefC play important roles in H. pylori resistance to bile salts and ceragenins.

Gastroesophageal reflux episodes in asthmatic patients and their temporal relation with sleep architecture

Gastroesophageal reflux (GER) is common in asthma patients and can contribute to sleep disruption. The aim of the present study was to determine the time-related distribution of GER events together with their impact on sleep in asthmatic subjects with GER disease symptoms. The inclusion criteria were: 18-65 years, controlled moderate to severe asthma and GER-compatible clinical evidence. The exclusion criteria were: chronic obstructive lung disease, smoking, infections of the upper airways, use of oral corticosteroids, other co-morbidities, pregnancy, sleep-related disorders, night-time shift work, and the use of substances with impact on sleep. Asthmatic patients with nocturnal symptoms were excluded. All-night polysomnography and esophageal pH monitoring were recorded simultaneously. Of the 147 subjects selected, 31 patients and 31 controls were included. Seventeen patients were classified as DeMeester positive and 14 as DeMeester negative. Both groups displayed similar outcomes when general variables were considered. Sleep stage modification one minute prior to GER was observed in the DeMeester-positive group. Awakening was the most frequent occurrence at GER onset and during the 1-min period preceding 38% of the nocturnal GER. Sleep stage 2 was also prevalent and preceded 36% of GER events. In the DeMeester-negative group, awakening was the most frequent response before and during GER. Modifications in sleep stages, arousals or awakenings were associated with 75% of the total GER events analyzed during the period of one minute before and after the fall of esophageal pH below 4 in the DeMeester-positive group. These data provide evidence that sleep modifications precede the GER events in asthmatic patients.

Bronchial responsiveness during esophageal acid infusion

Among the possible mechanisms explaining the worsening of asthma due to gastroesophageal reflux disease (GERD) is the increase in bronchial hyperresponsiveness. The effects of GERD on bronchial hyperresponsiveness in patients with bronchial asthma have yet to be studied in significant detail. The aim of this study was to determine the effects of esophageal acid perfusion on bronchial responsiveness to bradykinin in patients with both asthma and GERD. In 20 patients with asthma and GERD disease, esophageal pH was monitored with a pH meter and bronchial responsiveness was evaluated by aerosol inhalation of bradykinin during esophageal acid perfusion and, 24 h earlier or later the patients were submitted to another bronchial provocation test without acid infusion. No significant changes were observed in FEV(1), FEF(25-75%), FVC, or PEF during acid perfusion. The response to the bronchial provocation test did not differ between the control day and the day of acid infusion (p = 0.61). The concentration provoking a 20% fall in FEV(1) (geometric mean +/- geometric SD) was 1.09 +/- 5.84 on the day of acid infusion and 0.98 +/- 5.52 on the control day. There is no evidence that acid infusion changes bronchial responsiveness to bradykinin. These findings strongly question the significance of acid infusion as a model to study the pathogenesis of GERD-induced asthma.

Bile reflux index after therapeutic biliary procedures

Background

Therapeutic biliary procedures disrupt the function of the sphincter of Oddi. Patients are potential "bile refluxers". The aim of this study was to assess how these procedures affect the histology-based bile reflux index (BRI), which can be used to reflect duodenogastric reflux (DGR).

Methods

Gastric antrum and corpus biopsies were collected from 131 subjects (56 men, 75 women; mean age, 55.9 ± 15.6 years). Group 1 (Biliary group-BG; n = 66) had undergone endoscopic sphincterotomy, endoscopic stenting, or choledochoduodenostomy for benign pathology; Group 2 (n = 20) had undergone cholecystectomy alone; and Group 3 (n = 6) Billroth II gastroenterostomy. Group 4 (no cholecystectomy; n = 39) had upper endoscopy with normal findings and served as controls. BRI > 14 indicated DGR (BRI [+]). To eliminate confounding effects of Helicobacter pylori (Hp) infection, comparisons were made according to Hp colonization.

Results

Fifty-nine subjects (45%) were Hp (+). The frequencies of BRI (+) status in antrum and corpus specimens from Hp (-) BG patients were 74.3% and 71.4%, respectively (85.7% for both antrum and corpus for choledochoduodenostomy). Corresponding results were 60% and 60% for Group 2, 100% (only corpus) for Group 3, and 57.1% and 38.1% for controls (BG, Group 2, and Group 3 vs controls – p > 0.05 antrum, p < 0.05 corpus). Fifty-four BG patients had previously undergone cholecystectomy. Excluding those, the rates of BRI (+) in Hp (-) BG patients were 75% antrum and 62.5% corpus (p > 0.05 for both vs. Group 2).

Conclusion

Patients who had undergone biliary procedures showed similar bile-related histological changes in both corpus and antrum biopsies, but the changes seen in controls were more prominent in the antrum than corpus. Therapeutic biliary procedures increase the rate of BRI (+) especially in the case of choledochoduodenostomy. Therapeutic biliary procedures without cholecystectomy also increase the rate of BRI (+) similar to that observed in patients with cholecystectomy.

[Surgical treatment of duodeno-gastro-esophageal reflux disease: duodenal switch]

AIMS

To evaluate the efficacy of duodenal switch operation for patients with duodeno-gastroesophageal reflux disease.

METHODS

Four female patients with therapy resistant epigastric pain and biliary regurgitation were enrolled in the study. In all cases, abnormal duodeno-gastric reflux was confirmed by 24-hour Bilitec monitoring. The average age of the patients was 41.75 years (range 32-53) and three of them had a cholecystectomy in the past. Importantly, all patients had previously undergone fundoplication, which had to be repeated in one of them due to recurrent symptoms. More recently, a duodenal switch procedure was performed in these four patients. Their mean follow-up time was 24.25 months (range 21-30).

RESULTS

Duodenal switch was performed without any perioperative complications. A good clinical outcome was found in all patients on their follow up; however, an abnormal acidic exposure was found in one case on 24-hour oesophageal pH monitoring.

CONCLUSION

Recurrent epigastric complaints developing after anti-reflux surgery in patients with a previous diagnosis of gastroesophageal reflux disease might be due to an abnormal duodeno-gastric reflux. Previous cholecystectomy may increase the risk of biliary reflux. Duodenal switch procedure can be applied with good results in patients with therapy resistant abnormal duodeno-gastric reflux confirmed with Bilitec monitoring.

Le reflux biliaire duodéno-gastrique et gastro-œsophagien

This study reviews current data regarding duodenogastric and gastroesophageal bile reflux-pathophysiology, clinical presentation, methods of diagnosis (namely, 24-hour intraluminal bile monitoring) and therapeutic management. Duodenogastric reflux (DGR) consists of retrograde passage of alkaline duodenal contents into the stomach; it may occur due to antroduodenal motility disorder (primary DGR) or may arise following surgical alteration of gastoduodenal anatomy or because of biliary pathology (secondary DGR). Pathologic DGR may generate symptoms of epigastric pain, nausea, and bilious vomiting. In patients with concomitant gastroesophageal reflux, the backwash of duodenal content into the lower esophagus can cause mixed (alkaline and acid) reflux esophagitis, and lead, in turn, to esophageal mucosal damage such as Barrett's metaplasia and adenocarcinoma. The treatment of DGR is difficult, non-specific, and relatively ineffective in controlling symptoms. Proton pump inhibitors decrease the upstream effects of DGR on the esophagus by decreasing the volume of secretions; promotility agents diminish gastric exposure to duodenal secretions by improving gastric emptying. In patients with severe reflux resistant to medical therapy, a duodenal diversion operation such as the duodenal switch procedure may be indicated.

Elevated cyclooxygenase-2 expression in patients with early gastric cancer in the gastric pylorus

BACKGROUND

Duodenogastric reflux after surgery increases the risk of gastric carcinoma. To determine whether bile reflux influences the development of gastric cancer in patients who have not had surgery, we compared cyclooxygenase-2 (COX-2) immunoreactivity in early gastric cancer originating from the gastric pylorus and that originating from other locations. We also examined the effects of bile acids on the expression and activity of COX-2 in gastric cells in vitro.

METHODS

Tumor sections from 79 patients who underwent endoscopic mucosal resection for early intestinal-type gastric carcinoma were stained using a COX-2-specific monoclonal antibody. Immunoblotting of COX-2 was used to assess the effects of bile acids on COX-2 expression and activity in human gastric cell lines.

RESULTS

Among the 79 early gastric cancer lesions studied, 13 (16%) arose in the gastric pylorus. In this group, COX-2 immunoreactivity was negative to weak in 38% (5 of 13 lesions) and moderate to strong in 62% (8 of 13 lesions). In the control group, COX-2 immunoreactivity was negative to weak in 70% (46 of 66 lesions) and moderate to strong in 30% (20 of 66 lesions). COX-2 expression was significantly elevated in early gastric cancer located in the gastric pylorus, compared with that in the other locations. In human gastric cell lines, bile acids induced COX-2 expression, mediated by the ERK 1/2 mitogen-activated protein kinase pathway.

CONCLUSIONS

COX-2 expression is elevated in early gastric cancer of the gastric pylorus, a common site of gastric cancer. Bile acids induced COX-2 expression in human gastric cell lines, suggesting a role of bile reflux in gastric carcinogenesis.

Mechanisms underlying duodeno-gastric reflux in man

BACKGROUND

Recent studies suggest that duodeno-gastro-oesophageal reflux (DGER) contributes to the occurrence of reflux oesophagitis and Barrett's oesophagus. The mechanisms underlying duodeno-gastric reflux (DGR), a prerequisite for DGER, are poorly understood.

AIMS

To study the occurrence of DGR in relation to interdigestive and postprandial gastroduodenal motility.

SUBJECTS AND METHODS

Ten healthy subjects underwent stationary gastroduodenal manometry with simultaneous duodenal and antral Bilitec recording 4 h before and 5 h after ingestion of a liquid meal. Eight volunteers underwent the same study, with administration of erythromycin postprandially.

RESULTS

During the interdigestive phase II, all volunteers had short DGR episodes. Postprandially, DGR occurred in all subjects, on average 39 +/- 28 min after the start of the meal, and was cleared from the stomach after 242 +/- 23 min. Induction of increased antral motility and of a premature phase III, by administration of erythromycin, was associated with faster gastric DGR clearance. However, there was no direct temporal relationship between erythromycin-induced gastric phase III and erythromycin-induced DGR clearance.

CONCLUSION

In healthy subjects, duodenogastric reflux occurs sporadically in the interdigestive state and is a normal phenomenon in the postprandial period. Erythromycin induces faster clearance of DGR from the stomach, which depends on enhanced antral contractile activity rather than premature phase III.

Effects of duodenogastric reflux on gastrin cells, somatostatin cells and serotonin cells in human antral gastric mucosa

Duodenogastric reflux (DGR) has been found to give rise to a hypochlorhydria secondary to alkaline reflux. We investigated whether there is a link between DGR and the gastrin, somatostatin, and serotonin cell numbers and the granular content of gastrin, somatostatin, and serotonin in endocrine cells in human antral mucosa. We investigated 38 selected Helicobacter pylori-negative patients with visual primary excessive DGR in upper endoscopy and symptoms of epigastric pain and bile vomiting. Ten control patients were included in this study. None of the patients had peptic ulcer or had received any medication. Antrum (10 biopsies from five different zones: the lesser and major curvature, the anterior and posterior wall, and the pylorus) and corpus (two biopsies from major curvature about 10 cm below the cardia) biopsy specimens were collected for routine histology, as well as for light and electron immunohistochemistry. In patients without atrophy or intestinal metaplasia and in patients with mild atrophy or mild intestinal metaplasia, the number of gastrin and somatostatin cells was not different from that in controls. In moderate atrophy or moderate intestinal metaplasia, however, the number of gastrin and somatostatin cells decreased. Serotonin cell number was significantly higher in all patients with DGR as compared with controls. The mean somatostatin granular content was increased (3.6+/-0.2 vs. 3.2+/-0.1). In addition, lysosomes with engulfed somatostatin granules were found. The mean serotonin granular content was decreased (2.3+/-0.3 vs. 2.9+/-0.3), while the mean gastrin granular content remained unchanged (2.5+/-0.3 vs. 2.4+/-0.2). Ultrastructurally, the granules in serotonin-positive cells corresponded to the gastric variant or to the intestinal variant of serotonin cells. The endocrine cells were found to have few granules positive for serotonin. It is concluded that DGR inhibits somatostatin granular release, but stimulates both serotonin granular release and serotonin cell growth.

Esophageal visceral sensitivity to bile salts in patients with functional heartburn and in healthy control subjects

Patients with nonerosive gastroesophageal reflux disease often have relatively low esophageal acid exposure and respond suboptimally to gastric acid suppression. In these patients, other constituents of gastric contents may induce esophageal symptoms. We have demonstrated that gastric contents can cause heartburn when the gastric pH >4. (Aliment Pharm Ther 14:129-134, 2000). The aim of this study was to determine relative sensitivities to chenodeoxycholic and ursodeoxycholic acids, and 0.1 N HCl, administered as provocative perfusion tests. Patients with functional heartburn and healthy control subjects were evaluated. Patients underwent a modified Bernstein acid infusion test and esophageal Barostat balloon distention. Time and volume to pain were recorded. Barostat balloon distention was performed using our standard protocol. Stepwise distentions were performed and pain was recorded. Sensitivity to chenodeoxycholic acid (Cheno) and Ursodeoxycholic acid (Urso) were assessed similarly to the Bernstein test using 2 mM concentrations of each, followed immediately by 5 mM if no pain was reported with 2 mM. Volume of bile acid infusion and length of time until pain was induced were assessed and compared to the same endpoints for acid sensitivity. "Total" time and "total" volume to induce pain were calculated for Cheno and Urso. Least-squares means were generated and two-tailed t-tests and regression analyses were performed (P < 0.05 level of significance). Ten functional heartburn patients and six healthy controls were evaluated (3 M, 13 F; age range, 19 to 56 years). Since five of six controls had pain with acid infusion (hypersensitive), all subjects were analyzed as one group. Only three subjects (all controls) had no pain with infusion of 2 mM Cheno and received the follow-up infusion of 5 mM. These same three subjects tolerated the maximum infusion (150 ml and 15 min) of 5 mM Cheno. Nine subjects did not have pain with 2 mM Urso and received the follow-up infusion of 5 mM Urso (five functional heartburn, four controls). Significantly more subjects tolerated the maximum bile acid infusion of 2 mM Urso vs 2 mM Cheno (nine vs three; P < 0.05, Chi-square test). The pain threshold (volume and time) for Urso was significantly higher than that for Cheno and acid (P < 0.05), and the pain threshold for Cheno was significantly higher than that for acid (P < 0.05). Conclusions are as follows: (1) Bile acids differ in their ability to induce pain. (2) Changing bile acid composition by treatment with Urso may change symptom presentation and symptom severity in patients with bile acid-induced esophageal pain.

Chemotactic response of Helicobacter pylori to human plasma and bile

To clarify further the role of chemotaxis in Helicobacter pylori colonization, the in vitro bacterium response to human plasma and bile (secretions containing chemoeffector compounds that are present in the gastric mucus layer) was examined. Human plasma, after dilution to 1 % (v/v) with buffer, was found to be a chemoattractant for the motile bacillus. Human gall-bladder bile, after dilution to 2 % (v/v) with buffer, was found to be a chemorepellent, but did not cause the motility of the bacillus to be diminished after prolonged exposure. The basis of the chemoattractant effect of plasma was explored by examining how urea and 12 amino acids found in plasma affected the taxis of H. pylori. Urea and the amino acids histidine, glutamine, glycine and arginine were the strongest chemoattractants. Other amino acids were chemoattractants, with the exceptions of aspartic and glutamic acids, which were chemorepellents. The basis of the chemorepellent effect of bile was explored by examining how the six most abundant conjugated bile acids in human bile affected the taxis of H. pylori. All the bile acids were chemorepellents, with the greatest effects being demonstrated by taurocholic and taurodeoxycholic acids. The implications of these findings for H. pylori colonization of gastric epithelium are discussed.

Acid, weakly acidic and non-acid gastro-oesophageal reflux: differences, prevalence and clinical relevance

In patients with gastro-oesophageal reflux disease (GORD), oesophageal symptoms and mucosal damage traditionally are related to acid-reflux episodes with pH lower than 4. Oesophageal or extra-oesophageal symptoms of GORD may also be associated with less acidic reflux (pH 4-7). New methodologies have evolved to complement pH monitoring for characterisation of less acidic gastro-oesophageal reflux. This review will focus on definition, detection, pathophysiology and symptom association of weakly acidic and non-acid reflux, in both adult and paediatric populations.

Duodenogastric Reflux-induced (Alkaline) Esophagitis

Duodenogastric reflux is the retrograde flow of duodenal contents into the stomach that then mix with acid and pepsin. These agents can reflux into the esophagus (ie, duodenogastroesophageal reflux ) and cause gastroesophageal reflux disease (GERD) and its complications, including stricture, Barrett's esophagus, and adenocarcinoma of the esophagus. Medical and surgical treatments of DGER can be difficult. Best medical treatment is proton-pump inhibitors, which decrease DGER by inhibiting both gastric acidity and volume, making less gastric contents available to reflux into the esophagus. The addition of the gamma-aminobutyric (GABA(B)) receptor agonist baclofen may further reduce DGER in patients not responding to proton-pump inhibitors. Bile acid-binding agents (aluminum-containing antacids, cholestyramine, sucralfate, urosodeoxycholic acid) have physiologic rationale, but their efficacy is unproven. Prokinetic agents can reduce DGER and its upper gastrointestinal symptoms by promoting increased gastric emptying. In patients with medically refractory symptoms, a Roux-en-Y diversion or duodenal switch operation may be helpful.

Bile acids in gastric fluids from llamas and alpacas with and without ulcers

To investigate the relationship between duodenogastric reflux and ulceration, gastric fluid was collected from the 1st (n = 26) and 3rd (n = 45) gastric compartments of llamas and alpacas during postmortem examination. Gastric fluids were analyzed for the presence of bile acids. Additionally, the 3rd compartment was examined grossly for the presence of erosions or ulcers, and the intestines were examined for evidence of fluid distention. Detectable bile acids were found in the 3rd compartment fluid of 1 of 28 camelids without ulcers, 7 of 14 camelids with ulcers, and 3 of 3 camelids with intestinal distention. Third compartment bile content was significantly higher in camelids with ulcers (median = 2.9 micromol/L) or intestinal distention (median = 371.5 micromol/L) than those with neither (median = 0 micromol/L). Bile acids were detected in the 1st gastric compartment in only 2 camelids. These findings suggest a reflux of duodenal contents, including bile acids, into the 3rd compartment in camelids with ulcers, similar to what is seen in camelids with poor intestinal emptying. Whether bile reflux was the cause of the ulcers or occurred after or concurrent to their development remains unknown.

Gastric bilirubin monitoring to assess duodenogastric reflux

Duodenogastric reflux (DGR) was assessed with 24-hour gastric bilirubin monitoring in 345 patients (219 men; 49 +/- 13 years) with foregut symptoms and 41 healthy subjects (24 men, 28 +/- 5 years). Bilirubin exposure was measured as percent time above absorbance level 0.25 and excessive DGR was defined above the 95th percentile of normal values (>24.8%). DGR was highest following Billroth II gastric resection (60 +/- 24%, N = 15). Patients after cholecystectomy (28 +/- 25%, N = 25), patients with gastroesophageal reflux disease (24 +/- 24%, N = 199), and patients with nonulcer dyspepsia (23 +/- 21%, N = 61) had a significantly higher exposure to DGR than healthy subjects (7 +/- 8%, P < 0.0001). In conclusion, gastric bilirubin monitoring is useful for the assessment of DGR specifically in symptomatic patients following gastric resection. Increased amounts of DGR may further be of clinical importance in patients with reflux disease or nonulcer dyspepsia and following cholecystectomy.

No association between gallstones and gastroesophageal reflux disease

OBJECTIVES

Gallstones and hiatal hernia reportedly have been linked to similar dietary factors prevalent in western countries, and patients with cholelithiasis or previous cholecystectomy have been reported to have more duodenogastric reflux than healthy controls. Nonetheless, the contribution of duodenogastric reflux to the development of gastroesophageal reflux disease (GERD) remains controversial. The present study was aimed to assess the association between gallstone disease and GERD.

METHODS

Outpatients from general medical clinics who underwent upper GI endoscopy and abdominal ultrasonography were recruited into a case-control study. A case population of 790 patients with various grades of GERD was compared to a control population of 407 patients without GERD. In a multivariate logistic regression, the presence of GERD served as the outcome variable, whereas the presence of gallstones, hiatal hernia, social habits, and demographic characteristics served as predictor variables.

RESULTS

No associations were found between the presence of cholelithiasis or previous cholecystectomy and GERD or between the presence of cholelithiasis or previous cholecystectomy and hiatal hernia. The severity of GERD also remained unaffected by the presence of gallstones. The occurrence of GERD was influenced only by hiatal hernia (odds ratio [OR] = 3.15, 95% CI = 2.44-4.08), alcohol consumption (OR = 1.47, CI = 1.08-1.99), and not by cholelithiasis (OR = 1.02, CI = 0.68-1.51), or cholecystectomy (OR = 0.90, CI = 0.64-1.28). The frequency of GERD among hiatus hernia patients with gallstones (437/592 = 74%) was similar to the frequency of GERD among hiatus hernia patients without gallstones (168/220 = 76%, p = 0.516).

CONCLUSIONS

Neither cholelithiasis nor cholecystectomy poses a risk for the occurrence of GERD or hiatal hernia. Gallstone disease does not seem to influence the integrity of the esophageal mucosa through GERD.

Bile acid reflux and possible inhibition of Helicobacter pylori infection in subjects without gastric surgery

Bile acids are generally known to inhibit growth of Helicobacter pylori in vitro, but whether they do so in humans with no gastric surgery has been uncertain. The present study addresses this issue. Among healthy control subjects with preserved acid secretion, H. pylori-positive subjects were older and had lower gastric bile acid concentrations than H. pylori-negative subjects (P < 0.05). Among gastric ulcer patients with preserved acid secretion, H. pylori-positive patients had a higher basal acid output than H. pylori-negative patients (P < 0.05). Among H. pylori-positive subjects with preserved acid secretion, duodenal ulcer patients had a higher basal and maximum acid output than healthy control subjects (P < 0.01). In conclusion, gastric bile acids may suppress initial stages of H. pylori infection in subjects without gastric surgery. However gastric bile acids may have little effect on peptic ulcer disease, once H. pylori infection is established.

Increased acid and bile reflux in Barrett's esophagus compared to reflux esophagitis, and effect of proton pump inhibitor therapy

OBJECTIVES

Barrett's metaplasia is an acquired condition resulting from longstanding gastroesophageal reflux disease. Approximately 10% of esophagitis patients develop Barrett's esophagus. There is increasing evidence that duodenogastroesophageal reflux plays a role in the progression of disease. We further analyzed the correlation of acid and biliary reflux with reflux esophagitis and Barrett's esophagus and tested the effects of proton pump inhibitor therapy.

METHODS

Patients with either reflux esophagitis (group 1) or Barrett's esophagus (group 2) prospectively underwent simultaneous 24-h esophageal pH and bile reflux testing without any therapy affecting acid secretion or GI motility. A total of 16 patients in group 1 and 18 patients in group 2 were tested again under proton pump inhibitor therapy.

RESULTS

Acid and bile exposure were significantly increased in Barrett's patients (n = 23) compared to 20 esophagitis patients (median percentage of time that pH was <4 was 24.6% vs 12.4%, p = 0.01, median percentage of time that bilirubin absorbance was >0.2 was 34.7% vs 12.8%, p < 0.05). During therapy, both acid and bile reflux decreased significantly in both groups. Median percentage of time that pH was <4 and bilirubin absorbance was >0.2 before and during therapy was 18.2%/2.3% and 29.8%/0.7% (p = 0.001 and p = 0.001) in Barrett's esophagus patients versus 14.5%/3.6% and 21.5%/0.9% (p = 0.002 and p = 0.011) in esophagitis patients. There was no significant difference between the groups. In two esophagitis patients, bile reflux increased during therapy.

CONCLUSIONS

There is a good correlation of the duration of esophageal exposure to acid and bile with the severity of pathological change in the esophagus. Both acid and bile reflux is significantly suppressed by proton pump inhibitor therapy with exceptions among individual esophagitis patients. The prolonged simultaneous attack of bile and acid may play a key role in the development of Barrett's metaplasia.

Review article: the role of non-acid reflux in gastro-oesophageal reflux disease

The role of acid in the pathogenesis of gastro-oesophageal reflux disease (GERD) has been extensively studied and is well accepted. The role, if any, of non-acid reflux, in particular duodenogastro-oesophageal reflux, is much debated. The availability of new technology to detect non-acid reflux has heightened interest in this question. This article reviews the following: How do we define non-acid reflux? Does duodenogastro-oesophageal reflux (alone or in combination) cause oesophageal injury, symptoms or both? What is its role in complicated GERD? What methods are available to assess non-acid reflux? Does non-acid reflux need treatment and if so what modalities are available?

Contribution of acid and duodenogastro-oesophageal reflux to oesophageal mucosal injury and symptoms in partial gastrectomy patients [see comment]

BACKGROUND

The role of acid and pepsin in causing symptoms and oesophagitis is well established; however, the significance of duodenogastro-oesophageal reflux (DGOR) in this disorder is unclear.

AIMS

To understand the role of acid and DGOR in causing upper gastrointestinal (GI) symptoms and oesophageal mucosal injury in partial gastrectomy (PG) patients.

METHODS

Thirty two PG patients with upper GI symptoms were studied. Twenty four hour ambulatory acid and bilirubin measurements were obtained with Bilitec 2000 using glass electrode and fibreoptic sensor. Upper GI symptoms and oesophagitis were correlated with either acid or DGOR.

RESULTS

The PG patients were a heterogeneous group: 28% (9/32) had mixed reflux (acid+/DGOR+); 50% (16/32) had only DGOR (acid-/DGOR+); and 22% (7/32) had neither (acid-/DGOR-). Upper GI symptoms were associated with both mixed reflux (69%) and DGOR (24%). Six patients (67%) in the acid+/DGOR+ group had oesophagitis; no acid-/DGOR+ or acid-/DGOR- patients had oesophagitis. Mixed reflux showed a significant (p < 0.0001) association with oesophagitis, while DGOR did not (p = 0.3).

CONCLUSIONS

(1) The majority of upper GI symptoms and all cases of oesophagitis in the PG patients occurred in patients who had mixed refluxate (acid and DGOR); (2) DGOR without simultaneous acid reflux may cause symptoms, but was not associated with oesophagitis in this patient group.

Bile in the oesophagus: clinical relevance and ambulatory detection

BACKGROUND

Experimental work in animals has implicated a role for bile in the pathogenesis of several oesophageal mucosal diseases such as oesophagitis, Barrett's oesophagus and oesophageal adenocarcinoma. Recent descriptions of a high incidence of intestinal metaplasia at the gastro-oesophageal junction in patients without a classical 3-cm Barrett's columnar-lined segment, combined with a rising incidence in oesophageal and cardia adenocarcinoma, have stimulated interest in the causes of these conditions.

METHODS AND RESULTS

Animal studies concerned with defining the role of the various gastroduodenal reflux constituents in oesophageal mucosal injury are summarized and evidence for bile in the pathogenesis of Barrett's oesophagus and oesophageal adenocarcinoma is reviewed. The results of various techniques for clinical measurement of oesophageal bile reflux, such as aspiration, scintigraphy and pH monitoring, are evaluated and the significance of recent studies employing ambulatory fibreoptic bilirubin monitoring is discussed.

CONCLUSION

There seems little doubt that bile plays a significant role in oesophageal mucosal disease, in synergy with other constituents of reflux. Although ambulatory bilirubin monitoring is new, some intriguing findings have been reported and it is hoped that this technique will continue to shed light on the role of bile in the oesophagus.

Placebo-controlled trial of cisapride in postgastrectomy patients with duodenogastroesophageal reflux

Medical treatment of duodenogastroesophageal reflux in postgastrectomy patients has been disappointing. Using ambulatory esophageal bilirubin monitoring, we evaluated the efficacy of cisapride in this disorder. Ten chronically symptomatic partial gastrectomy patients (5 Billroth I, 5 Billroth II; 8 men; average age 57) with duodenogastroesophageal reflux were randomized to four weeks of either placebo or cisapride (20 mg four times a day) in a double-blind crossover study. Significantly improved patients continued to take cisapride for an additional four months. Duodenogastroesophageal reflux was assessed at baseline and after four weeks on each therapy. Daily diary recorded symptoms and mean monthly scores were determined. Global symptom improvements were assessed at the end of each treatment period. Compared to placebo, cisapride significantly (P < 0.05) decreased duodenogastroesophageal reflux. Overall symptom improvements were assessed at the end of each treatment period. Compared to placebo, cisapride significantly (P < 0.05) decreased duodenogastroesophageal reflux. Overall symptoms improved in 70% of patients on cisapride compared to 10% on placebo (P < 0.01). Mean monthly scores significantly (P < 0.05) improved for abdominal pain, regurgitation, and belching. These symptoms remained improved after four months of chronic therapy. We conclude that cisapride significantly reduces duodenogastroesophageal reflux and results in short- and long-term symptom improvements in postgastrectomy patients and that cisapride offers the first successful medical therapy for duodenogastroesophageal reflux in postgastrectomy patients.

Role of acid and duodenogastric reflux in esophageal mucosal injury: a review of animal and human studies

The role of acid and duodenogastric reflux (DGR) in the development of esophageal mucosal injury has been extensively investigated using both animal and human models. In this report, clinical and experimental data are reviewed. The mechanisms by which gastric and duodenal contents produce esophageal mucosal injury are also discussed. Acid and pepsin are unquestionably important in causing mucosal damage at low pH values in both animal and human models. Animal models suggest synergistic damaging potential for conjugated bile acids and HCI as well as that of unconjugated bile acids and trypsin in more neutral pH values. Human evidence for the involvement of bile and its constituents has been controversial; however, the advent of better technology to detect DGR is beginning to clarify the role of these constituents. The contribution of each methodology in clarifying the extent of involvement of DGR in esophageal mucosal injury is reviewed. Despite some conflicting results, preliminary human studies support the results from the animal data suggesting synergistic damaging effects for both bile and acid in esophageal mucosal injury. The implication of these studies in treating gastroesophageal reflux disease are discussed.

Duodenogastric reflux and foregut carcinogenesis

Epidemiologic cohort studies have established that after distal gastric resection, there is a higher risk of gastric carcinoma. It is likely that a main factor of this higher risk is the excessive duodenogastric reflux induced by surgery, because the incidence of stump carcinomas is higher in Billroth II than in Billroth I, and most of the stump carcinomas are located near the stoma. In addition, several groups of investigators have suggested that duodenogastric reflux per se induces stump carcinomas in rats. There is another human duodenogastric reflux, the primary duodenogastric reflux, through the pylorus. Experiments in animals have demonstrated that this type of duodenal reflux also induces gastric carcinomas in the antrum of the stomach that has not undergone surgery. Recent clinical attention has focused on the role of duodenogastric reflux in the pathogenesis of Barrett's esophagus and subsequent esophageal adenocarcinomas. Experimentally, reflux of duodenal contents into the esophagus can cause not only Barrett's esophagus and subsequent adenocarcinomas, but also squamous cell carcinomas. These findings suggest that duodenogastric reflux may be implicated in gastric and esophageal, that is, foregut carcinogenesis.

Profound duodenogastric reflux causes pancreatic growth in rats

Although duodenogastric reflux is a physiological event, excessive reflux may be a pathogenetic factor in several diseases of the foregut, including cancer. Long term profound duodenogastric reflux produces pancreatic and gastric tumours in rats. The trophic effect of surgically induced duodenogastric reflux on the pancreas was investigated and the mechanisms involved were examined. Rats with profound reflux from a split gastroenterostomy were compared with sham operated and unoperated controls after two and six weeks. In the six week experiment, one reflux and one sham group were given the cholecystokinin (CCK) receptor antagonist devazepide (25 nmol/kg/h). Duodenogastric reflux caused a significant increase in pancreatic weight, DNA, and plasma CCK and gastrin concentrations at both two and six weeks. Devazepide substantially reduced the pancreatic weight increase after six weeks but did not abolish it completely. CCK and gastrin were not affected by devazepide. These results suggest that CCK is largely responsible for the pancreatic growth induced by reflux but another factor may also be involved. The trophic effect of duodenogastric reflux may contribute to the increased incidence of pancreatic cancer reported after gastric surgery.

Different interdigestive antroduodenal motility patterns in chronic antral gastritis with and without Helicobacter pylori infection

Fasting antroduodenal motor activity was studied in 15 dyspeptic patients with chronic superficial antral gastritis and Helicobacter pylori infection (group A), 10 dyspeptic patients with chronic superficial antral gastritis without Helicobacter pylori infection (group B), and eight healthy control subjects (group C) by manometric recording of phases of the interdigestive migrating motor complex (MMC) prolonged over 240 min. A significantly lower incidence of activity fronts (phase III of MMC) starting from the antrum was observed in patients with gastritis and Helicobacter pylori infection vs patients without bacterial colonization (P = 0.013) and in these latter vs control subjects (P = 0.013). Likewise, the overall number of activity fronts was smaller in patients with gastritis than in healthy subjects (P = 0.034). Symptomatic evaluation was performed in the two groups of dyspeptic patients, without detecting any differences in frequency and severity of complaints. Our results show a significant reduction in the occurrence of interdigestive antral phase III of MMC in chronic gastritis associated with Helicobacter pylori infection, suggesting a possible relationship between fasting motility and bacterial colonization.

Abnormal plasma gut hormones in pathologic duodenogastric reflux and their response to surgery

Fasting and postprandial plasma levels of the gut hormones gastrin, cholecystokinin (CCK), secretin, glucose-dependent insulinotropic polypeptide, motilin, neurotensin, peptide YY (PYY), enteroglucagon, glucagon, insulin, and pancreatic polypeptide were measured in 11 patients with alkaline gastritis associated with excessive duodenogastric reflux not related to previous gastric surgery (primary DGR), 12 primary DGR patients after pancreatico-biliary diversion ("duodenal switch" procedure), and in 10 age-matched healthy controls. Gastric emptying of a semisolid oatmeal was also measured in patients with primary DGR and in patients after bile diversion. Fasting plasma levels of the distal gut hormone neurotensin and the pancreatic islet hormone insulin were significantly greater in patients with primary DGR compared with controls. Neurotensin levels were normal in patients studied after bile diversion. Postprandial plasma levels, incremental integrated and total integrated responses for CCK, secretin, insulin, neurotensin, PYY, and enteroglucagon, were significantly greater in patients with primary DGR compared with controls. The majority of these responses normalized after bile diversion; however, the postprandial response for insulin and enteroglucagon remained elevated. Patients with primary DGR had a rapid early postprandial phase of gastric emptying of solids, which showed a significant correlation with plasma neurotensin levels. Bile diversion produced a significant delay in this lag-phase of gastric emptying. These abnormalities in gut regulatory hormones appear to be adaptive changes to rapid early postprandial gastric emptying, probably related to antropyloric dysmotility, which has been implicated in the pathogenesis of this condition. Measurement of these gastrointestinal hormones may become useful in the diagnosis of primary DGR.

Effect of diets low and high in refined sugars on gut transit, bile acid metabolism, and bacterial fermentation

Increasing consumption of refined sugar has been implicated in many gastrointestinal disorders on epidemiological grounds. Nine volunteers agreed to participate in a study comparing the effects of a diet containing 165 g refined sugar/day with a diet of only 60 g/day on gut transit, bile acid metabolism, and fermentative activity of the intestinal flora. The wet and dry weight, pH, and water content of the stools were similar on the two diets. On the high sugar diet mouth-to-anus transit time was significantly prolonged, despite a shortened mouth-to-caecum transit time. The faecal concentration of total bile acids and the faecal concentration of secondary bile acids increased significantly. Diet affected neither the serum bile acid pattern nor the concentration. Breath hydrogen tests showed significantly enhanced H2 production on the high sugar diet. We conclude that the quantity of refined sugar in the diet can significantly influence gut function and the composition of bowel contents.

New technique for analysing conjugated bile acids in gastric juice

A new technique of high performance liquid chromatography (HPLC) was developed for the analysis of conjugated bile acids in gastric juice. The assay is rapid, sensitive, and highly specific for bile acid conjugates over the range 30-10,000 mumol/l and is not affected by the presence of food. Ten patients with a variety of common upper gastrointestinal disorders underwent continuous gastric aspiration for 16 hours, including a fasting, post-prandial, and nocturnal period, and aliquots of aspirates were analysed every two hours by the HPLC technique for the six most prevalent bile acid conjugates present in human hepatic bile. Intragastric bile acid concentrations were lowest in the post-prandial period and highest in the early hours of the morning. Conjugated bile acid proportions, or profiles, varied considerably from patient to patient, but tended to remain uniform over time in individual patients. It is concluded that HPLC is superior to enzymatic techniques for the analysis of conjugated bile acids in the upper gastrointestinal tract.

Duodenogastric reflux and gastric histology after cholecystectomy with or without sphincteroplasty

Sixteen patients who had undergone cholecystectomy plus sphincteroplasty, 14 cholecystectomized patients and ten control patients were studied to evaluate whether differences existed in duodenogastric reflux and whether these were related to morphological damage of the gastric mucosa. Duodenogastric bile reflux during fasting was evaluated by measuring the concentration of total bile acids (by an enzymatic method) and single bile acids in the gastric juice by high performance liquid chromatography. The damage was evaluated histologically by systematic endoscopic biopsy of the antrum and body of the stomach. There was a statistically significant difference in fasting bile reflux between the three groups (Kruskal-Wallis test, P less than 0.001), and the group that underwent cholecystectomy plus sphincteroplasty had a significantly higher median value than the cholecystectomized group (P less than 0.05) and the control group (P less than 0.01). The distribution of chronic antral atrophic and superficial gastritis was different in the three groups (chi 2 test, P less than 0.005). Chronic atrophic gastritis was associated with cholecystectomy plus sphincteroplasty (P less than 0.01), while chronic superficial gastritis was more frequent in cholecystectomized patients. These results suggest that there may be more duodenogastric reflux after cholecystectomy plus sphincteroplasty than after cholecystectomy alone, and that there may be a correlation between the amount of duodenogastric reflux and the severity of mucosal damage.

Duodenogastric reflux of bile acids, gastrin and parietal cells, and gastric acid secretion before and 6 months after cholecystectomy

In order to evaluate the effect of cholecystectomy on the gastric mucosa, the duodenogastric reflux of total and single bile acids, the number of parietal and gastrin cells, and the volume of gastric acid secretion were examined in 15 patients with gallstones and functioning gallbladders before and 6 months after cholecystectomy. The duodenogastric reflux of the total bile acids increased from a mean preoperative value of 1.9 mumol/hour to a mean postoperative value of 21 mumol/hour (p = 0.008). The duodenogastric reflux of all single bile acids increased after cholecystectomy, with a higher increase in glycoconjugated compared with tauroconjugated bile acids. The parietal cells decreased from a mean preoperative value of 82.8 to a mean postoperative value of 68.7 (p = 0.05), whereas there was only a mild increase in the number of gastrin cells; the output of gastric acid remained unchanged. The variation of the gastrin cells before and after cholecystectomy was negatively correlated only with the variation of taurocholic acid (r = -0.50, p = 0.05), while the variation of the parietal cells was mildly correlated with all single bile acids (r = 0.35-0.50, 0.05 less than p less than 0.02). These findings show an increased duodenogastric reflux of bile acids 6 months after cholecystectomy with a mild morphologic alteration of the gastric mucosa.

Continuous 99mTc-HIDA infusion as a method for measuring duodenogastric reflux

The continuous 99mTc-HIDA infusion test is presented as a method for measuring duodenogastric reflux as well as for studying biliary elimination of the compound when it is administered by constant intravenous infusion. Thirty patients were studied: (a) ten patients with a T tube placed in the biliary tree were used to study the elimination of 99mTc-HIDA in the bile; (b) ten normal subjects were used as a control group; and (c) ten patients were studied who had undergone Billroth I gastrectomy for peptic ulceration. Studies of subjects in groups (b) and (c) were used to assess duodenogastric reflux by this test, correlating it with the measurement of bile acids in gastric juice. When 99mTc-HIDA was administered by constant intravenous infusion it resulted in an increased elimination in bile for the first 80-100 min, and the concentration in bile then remained relatively constant for the rest of the test. With respect to the duodenogastric reflux study group, reflux rates in the patients who had been operated on were higher than those in the control group, with statistically significant differences. Minimum reflux rates were found in the normal subjects. Assessment of reflux by 99mTc-HIDA correlated closely with the results of bile acid concentrations in Billroth I patients (r = 0.75, P less than 0.001) and control subjects (r = 0.85, P less than 0.001). Our results demonstrate that continuous 99mTc-HIDA perfusion is a useful, accurate and objective method for measuring duodenogastric reflux.

Acid-related disorders: what are they?

'Acid-related disorders' is a term used to describe a whole range of conditions from the Zollinger-Ellison syndrome, where acid is entirely responsible for the problems, to aerophagia and motility-type non-ulcer dyspepsia, where acid plays little if any role in the dyspeptic symptoms. Careful evaluation of the patient's symptoms is required to establish the basis for the dyspepsia and from that, careful selection can be made for any investigations that might be needed. These symptoms are the basis for advising on the most effective management--but as many doctors and patients erroneously attribute dyspepsia solely to acid, it is all too easy for inappropriate treatment to be offered. Acid is not the only cause of dyspeptic symptoms. Dyspepsia is a very common complaint with many causes. Acid and pepsin are often held responsible for these symptoms, by both the medical profession and the lay public. The term, 'acid-related disorders' is used to embrace this wide variety of conditions in which acid may play a part. However, in spite of current folklore, it is a spectrum of conditions ranging from situations where acid is crucial to conditions where acid may play little part.