Interrelationships among gastric mucosal morphology, secretion, and motility in peptic ulcer disease

Gastric emptying of solids in long-term NSAID users: correlation with endoscopic findings and Helicobacter pylori status

OBJECTIVE

Prostaglandins regulate gastric motor function. Inhibition of prostaglandins by nonsteroidal antiinflammatory drugs (NSAIDs) may alter gastric emptying. To study gastric emptying of solids and its relation to endoscopic findings and Helicobacter pylori in patients receiving long-term NSAIDs, we undertook this study.

METHODS

Ninety-five patients with arthritis, 65 taking long-term NSAIDs (Group I) and 30 not taking NSAIDs (Group II) were studied. Presence of dyspeptic symptoms was determined using a questionnaire. Mucosal damage was determined by endoscopy. H. pylori was detected by antral biopsies for rapid urease test and histology. Gastric emptying for solids was evaluated using a scintigraphic method. Thirty healthy volunteers were used as controls for gastric emptying (Group III). Patients with peptic ulcer were excluded from the analysis of gastric emptying. Logistic regression analysis was performed to identify predictive factors for gastric emptying.

RESULTS

Nineteen patients from Group I with peptic ulcers were excluded. Dyspeptic symptoms were seen in 24 (52%) Group I and seven (23%) Group II patients. Gastroduodenal erosions were seen in 10 (21.7%) Group I patients and four (13.3%) Group II patients. H. pylori was detected in 17 patients in Group I (36.9%) and Group II (56.6%). Gastric emptying was delayed in 24 (52%) Group I patients, six (20%) Group II patients (p < 0.001), and in none of the Group III controls. The mean gastric emptying times were 99.5 (15.6) min and 89 (17.7) min for Groups I and II, respectively (p < 0.05). Endoscopic damage was found with similar frequency in Group I patients with delayed or normal gastric emptying. H. pylori infection was present in 37.5% Group I patients with delayed gastric emptying and in 36.3% with normal gastric emptying (p = ns). Logistic regression analysis identified NSAID therapy as the single factor most predictive of delayed gastric emptying.

CONCLUSION

Delayed gastric emptying was seen in 52% of patients on long-term NSAID therapy.

In vitro motility disorders associated with displaced abomasum in dairy cows

The objective of this study was to investigate in vitro abomasal motility in dairy cows diagnosed with displaced abomasum. Longitudinal muscle myenteric plexus preparations originating from the abomasal antrum of control cows, and cows diagnosed with left displaced abomasum (LDA), right displaced abomasum (RDA) or abomasal volvulus (AV) were used. In control preparations electrical field stimulation evoked an immediate cholinergic contractile response exceeding amplitude of basal contractions by 60%. In contrast, contractile activity was significantly inhibited during electrical stimulation in LDA, RDA and AV by 47%, 66% and 45%, respectively. This inhibition was reversed in the presence of L-NAME. The staining intensity of NADPH-positive myenteric neurones was significantly higher in displaced abomasa than in controls. Concentration-response curves indicated that preparations from displaced abomasa showed reduced sensitivity to acetylcholine. This study demonstrated motility disorders in displaced abomasa in vitro. The results suggested that abomasal displacement is associated with malfunctions at the level of the intrinsic nervous system combined with impaired cholinergic muscle responses. There appeared to be a predominance of nitrergic inhibitory mechanisms over excitatory mechanisms. These results might be of significance for diseases associated with gastric hypomotility and emptying disorders.

The effect of nematode infection upon intestinal smooth muscle function

Nematode infections are useful in studying both host defence and inflammation induced changes in intestinal physiology, including increased contraction by intestinal muscle. Our initial studies of the heightened muscle function found during T. spiralis infection led to investigations of the role of immune and inflammatory cells and mediators in the immunodulation of intestinal muscle function. By infecting various immunodeficient mouse strains, as well as gene transfer to the intestine, T lymphocytes, and in particular the CD4+ve subset were found to be responsible for altering smooth muscle function. However, eosinophils as well as the cytokine interleukin-4 may also be involved. Investigations also indicate a potential role for increased muscle function and propulsive activity in expelling nematode parasites. Mutant mice which suffer aberrant intestinal propulsion, or based upon an immunodeficiency, undergo reduced changes in muscle function during infection, undergo prolonged infections. While increased muscle function may be an adaptive host response, the changes in muscle function may persist long after the resolution of the infection. Thus understanding the mechanisms behind the immunomodulation of intestinal muscle function may also impact upon clinical gastroenterology, since motility disturbances in man often occur following enteric infections, or other inflammatory conditions of the bowel.

Helicobacter pylori infection, reflux esophagitis, and atrophic gastritis: an unexplored triangle

OBJECTIVE

H. pylori causes chronic gastritis, which may progress to peptic ulcer, gastric atrophy, or gastric cancer. However, little is known about the role of H. pylori infection in reflux esophagitis and the relationship between reflux esophagitis and atrophic gastritis needs to be clarified. We sought to identify the possible interrelationships among Helicobacter pylori infection, reflux esophagitis, and atrophic gastritis, to signal areas in which researchers should consider focusing their attention.

METHODS

A broad-based Medline search was performed to identify all related publications addressing H. pylori infection, atrophic gastritis, gastroesophageal reflux disease (GERD), secretion of gastric acid, and gastric motility published between 1966 and July 1997.

RESULTS

Whereas some studies have shown no significant association between H. pylori infection and reflux esophagitis, others have observed that the prevalence of H. pylori infection was lower in patients with GERD, implying a protective role. Eradication of H. pylori leads to occurrence of reflux esophagitis in some cases, but the mechanisms inducing posteradication reflux esophagitis are unknown. H. pylori infection may lead to atrophic gastritis (and hence hypochlorhydia) through both bacterial and host factors, although gastric atrophy and subsequent intestinal metaplasia are hostile to H. pylori because of hypochlorhydria. Although it has been reported that long-term proton pump inhibitor therapy for refractory reflux esophagitis may induce or enhance the development of gastric atrophy in H. pylori-infected patients, this relationship has been disputed.

CONCLUSIONS

H. pylori infection may be negatively associated with reflux esophagitis, but this requires confirmation. Research then needs to focus on whether this is explained through motility- or acid-related mechanisms. The potential costs of maintenance antireflux therapy may need to be taken into account when evaluating the cost effectiveness of anti-H. pylori therapy.

Helicobacter pylori and non-ulcer dyspepsia

The role of Helicobacter pylori in non-ulcer dyspepsia continues to be controversial. While there is general agreement that incident infection with H. pylori can induce self-limited symptoms, the evidence linking the infection to chronic upper abdominal pain or discomfort in the absence of peptic ulceration is equivocal. The prevalence of H. pylori is at most only slightly increased in non-ulcer dyspepsia over the background population taking into account age, socioeconomic status and past ulcer history. However, it is yet to be convincingly shown that H. pylori precedes the onset of non-ulcer dyspepsia. It is now accepted that H. pylori is not associated with a specific symptom profile. Recent evidence suggests that a subgroup with H. pylori and non-ulcer dyspepsia have increased acid secretion in response to gastrin-releasing peptide, but gastric motor and sensory function appears not to be affected by the infection. The most persuasive evidence for a causal relationship between the infection and non-ulcer dyspepsia will come from ongoing large multicentre randomized placebo controlled trials, as the relatively small therapeutic trials to date have been unconvincing.

Does Helicobacter pylori infection increase gastric sensitivity in functional dyspepsia?

The role of Helicobacter pylori infection in the pathogenesis of functional dyspepsia is debated. It is known that a substantial fraction of dyspeptic patients manifest a low discomfort threshold to gastric distension. This study investigated the symptomatic pattern in 27 H pylori positive and 23 H pylori negative patients with chronic functional dyspepsia, and potential relations between infection and gastric hyperalgesia. Specific symptoms (pain, nausea, vomiting, bloating/fullness, early satiety) were scored from 0 to 3 for severity and frequency (global symptom scores: 0-15). The mechanical and perceptive responses to gastric accommodation were evaluated with an electronic barostat that produced graded isobaric distensions from 0 to 20 mm Hg in 2 mm Hg steps up to 600 ml. Gastric compliance (volume/pressure relation) and perception (rating scale: 0-10) were quantified. Standard gastrointestinal manometry and recorded phasic pressure activity at eight separate sites during fasting and postprandially were also assessed. H pylori positive and H pylori negative patients manifested similar severity and frequency of specific symptoms and global symptom scores (mean (SEM)) (severity: 9.5 (2.0) v 9.0 (2.1); frequency: 10.8 (2.0) v 9.7 (2.2)). No differences were seen either in gastric compliance (53 (4) ml/mm Hg v 43 (3) ml/mm Hg) or in gastric perception of distension (slope: 0.50 (0.05) v 0.53 (0.06)). Postprandial antral motility was significantly decreased in H pylori positive patients (two hours motility index: 10.4 (0.6) v 12.6 (0.5); p < 0.05). It is concluded that H pylori infected patients with functional dyspepsia present no distinctive symptoms by comparison with H pylori negative counterparts and H pylori infection is associated with diminished postprandial antral motility but it does not increase perception of gastric distension.

Non-ulcer dyspepsia: does Helicobacter pylori matter?

Non-ulcer dyspepsia is a heterogenous disorder characterised by chronic or recurrent abdominal or retrosternal discomfort lasting for more than four weeks for which no cause can be determined. Helicobacter pylori has been implicated as a potential cause in a subset of patients but the association has not been proven and H pylori eradication in patients with non-ulcer dyspepsia has had variable results. Large well-controlled studies are needed to clarify the relationship.

The relationship between Helicobacter pylori-associated gastritis or ulcer disease and gastric emptying

Forty-five patients with Helicobacter pylori (HP)-associated gastritis or ulcer disease were included in this study. Radionuclide-labelled solid meals were used to calculate gastric emptying times (GETs) and carbon-14 urea breath tests (14C UBTs) were used to measure the HP colonies quantitatively. The patients were assessed according to the following two criteria: (a) the HP colony number (i.e. high or low) and (b) the recorded duration of the GET (i.e. long or short). There was no statistically significant difference in the incidence of abnormal GET between high and low 14C UBT patients or in the incidence of abnormal 14C UBT between long and short GET cases. In conclusion, no significant relationship between HP-associated gastritis or ulcer disease and GET was found in this study.

Helicobacter pylori-associated gastritis and dyspepsia. The influence on migrating motor complexes

Twenty-five patients with dyspepsia were included. In 19 patients with a median age of 48 (range, 20-72) years endoscopy and histologic examination of biopsy specimens from the antrum and corpus of the stomach showed Helicobacter pylori-positive gastritis as the only pathologic finding. In six patients with a median age of 42 (range, 32-56) years H. pylori-negative gastritis was found. After an overnight fast the patients underwent an ambulatory duodenal motility study for 6-8 h. Twenty-five young healthy men served as the control group. In patients with H. pylori-positive gastritis the duration of phase I of the migrating motor complex (MMC) was significantly shorter than in the control group. The median value was 33 min (quartiles, 24-49), and in controls 56 min (40-136 min). Phase II was of significantly longer duration, with a median value of 88 min (51-121 min) in the patient group and 39 min (22-89 min) in the control group. The duration of phase III and the whole MMC cycle was similar in the two groups. However, in the patients with H. pylori-negative gastritis the values of the duration of the different phases of the MMC were similar to those of the patients with H. pylori-positive gastritis. Nine patients were reexamined after eradication of the H. pylori infection, and the motility pattern had changed to the characteristics found in normals. In conclusion, the patients with dyspepsia and gastritis showed a disturbed motility pattern. The disturbance was similar whether there was colonization of H. pylori or not.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Fasting and postprandial gastrointestinal motility in ulcer and non-ulcer dyspepsia

This study aimed to compare fasting and postprandial gastrointestinal motor patterns in patients with ulcer and non-ulcer dyspepsia. Forty five subjects were studied: 10 with uncomplicated gastric ulcer, eight with uncomplicated duodenal ulcer, 18 with chronic idiopathic dyspepsia, and nine healthy asymptomatic controls. Gastrointestinal fasting and postprandial motor patterns were recorded using a low compliance perfusion technique. The interdigestive antral cumulative motility index, computed for 30 minutes before the appearance of duodenal activity fronts, and the number of activity fronts with an antral component were significantly less in patients with ulcers and those with non-ulcer dyspepsia compared with asymptomatic controls. The patient groups also had a reduced antral motor response to a solid-liquid test meal compared with healthy controls. Intestinal motor abnormalities (bursts of non-propagated phasic pressure activity and discrete clustered contractions) were recorded in a minority of patients, all with associated irritable bowel symptoms. In conclusion, antral hypomotility is a frequent but nonspecific motor abnormality in dyspepsia; abnormal motor patterns of the small bowel are less frequent and seem to be confined to patients with concomitant irritable bowel syndrome.

Gastrointestinal motor disturbances in functional dyspepsia

Since dyspepsia, as clinically defined, may constitute a heterogeneous group of conditions, it comes as no surprise that the pathophysiologic disturbances are diverse in character and prevalence. Furthermore, there is no convincing evidence that gastric and/or intestinal motor abnormalities differ among the clinical subgroups of dyspepsia. It is reasonable to suspect that a dyspeptic patient may have a gastrointestinal motor disturbance, since about half of them have delayed gastric emptying and antral hypomotility. However, proof of such motor disorder requires physiologic investigation. Even then, certainty as to whether motor abnormalities and symptoms have a causal relationship is often difficult to obtain.

Aspirin-induced changes in gastric function: role of endogenous prostaglandins and mucosal damage

The relative roles of prostaglandins and mucosal injury in aspirin-induced changes in gastric function were evaluated. Conscious rhesus monkeys received a subcutaneous injection of sodium bicarbonate or aspirin (25, 50, 100, or 150 mg/kg) and sodium bicarbonate or 150 mg/kg aspirin subcutaneously plus oral sucralfate (25 mg/kg twice a day). Gastric emptying and fluid and H+ outputs were determined during a fasting period and after an 80-ml water load using a 99mTc-diethylenetriaminepentaacetic acid dilution technique. At the end of each study, the monkeys were gastroscoped to assess mucosal damage, which was ranked blindly on a scale of 0 to 5. Biopsy samples were taken from antrum and fundus for determination of prostaglandins and histological evaluation. All doses of aspirin significantly suppressed prostaglandins in both the antrum and fundus. In contrast, the aspirin-induced increase in gastric mucosal injury was dose dependent. Aspirin also produced a dose-dependent decrease in gastric emptying that was significantly correlated with erosions scores. When aspirin-induced lesions were prevented by sucralfate, the inhibition of gastric emptying was blocked during the fasting period and was attenuated following the water load. Acid secretion was also decreased significantly by aspirin. This action was not modified by sucralfate protection, suggesting that aspirin has a direct inhibitory effect on parietal cell secretion. These data show that mucosal damage contributes significantly to the aspirin-induced changes in gastric function. Moreover, prostaglandins may play a role in the control of gastric emptying, especially during early phase of the response to a water load.

Chronic gastritis and gastroduodenal ulcer: a case control study on risk of coexisting duodenal or gastric ulcer in patients with gastritis

Chronic (atrophic) gastritis (AG) is common in active duodenal (DU) and gastric ulcer (GU) disease. In this case control study in consecutive prospective outpatients (571 cases and 1074 controls) who had undergone diagnostic upper gastrointestinal endoscopy and routine biopsies from both antral and body mucosa, we calculated the risk of coexisting active DU and/or GU in different gastritis of the antrum or body and according to grade (superficial gastritis, mild, moderate or severe atrophic gastritis). The risk of coexisting active gastroduodenal ulcer (ulcer in duodenum and/or stomach), as well as the risk of DU or GU, was dependent upon the presence and grade of gastritis in antrum and body mucosa. The risk of coexisting ulcer, as expressed as an age adjusted relative risk (RR) and calculated as odds ratio of gastritis in cases and controls, was significantly increased in the presence of superficial antral and body gastritis (RR = 8.5 (7.0-20.0) in men; RR = 5.8 (3.3-10.2) in women), as compared with the risk of ulcer in subjects with histologically normal mucosa (RR = 1). The risk of ulcer, and the risk of GU in particular, increased further with increasing severity of antral gastritis. In such patients with moderate or severe atrophic antral gastritis the RR of coexisting ulcer even exceeded 20 in men and 10 in women (RR = 25.6 (9.0-72.7) in men; RR = 11.7 (5.9-23.0) in women). On the other hand, the RR of ulcer, and the RR of DU in particular, was below 1 in the presence of atrophic gastritis in the gastric body, irrespective of the grade of gastritis in the antrum. We conclude that the type and grade of gastritis strongly predicts the risk of coexisting peptic ulcer, and that the risk of coexisting DU or GU increases with an increase in grade of AG of the antrum but decreases with an increase in grade of AG of the gastric body.

Chronic antral gastritis, Lewis(a+) phenotype, and male sex as factors in predicting coexisting duodenal ulcer

Chronic antral gastritis, Lewis(a+) phenotype (Le(a+)), and male sex are common in patients with peptic ulcer. To approximate the relative risks (RR) and possible interactions of these factors in predicting coexisting active duodenal (DU) or gastric ulcer (GU), a consecutive endoscopic series of 140 ulcer patients and 215 non-ulcer controls was examined. The Lea phenotype (Le(a+) versus Le(a-)) was determined immunohistochemically as binding of Le(a)+-specific monoclonal antibody to surface epithelial secretory mucosubstances in gastric biopsy specimens. The presence versus absence of the gastritis was determined histologically from antral specimens. The RRs of the factors in the prediction of ulcer were approximated as age-adjusted RRs when the risk of ulcer in the absence of the factors--that is, in the absence of gastritis, in female sex and in Le(a-) phenotype--was applied as a base line (RR = 1). A case-control design, logistic linear modelling, and the maximal likelihood method were used in estimation of the risks. The RR of coexisting distal ulcer (DU or pyloric or prepyloric GU) was increased in the presence of gastritis (RR = 10.2), in male sex (RR = 3.0), and in Le(a+) phenotype (RR = 1.8). The RR of proximal ulcer (angular or corpus GU) was increased in the presence of gastritis (RR = 35) but decreased in the presence of male sex (RR = 0.5) and Le(a+) phenotype (RR = 0.7). As predictors of both distal and proximal ulcer, gastritis, sex, and Le(a) phenotype were independent of each other; that is, their joint value in prediction of ulcer is a multiplicand of the marginal risks. Thus, a 50-fold difference in the joint RR could be approximated between the extreme risk groups for distal ulcer--that is, between Le(a+) males with gastritis and Le(-a) females with normal antrum. In a consecutive series of outpatient endoscopies, 45% of females and 8% of males could be categorized to these extreme 'low'- and 'high'-risk groups, respectively. We conclude that sex, Le(a) phenotype, and gastritis are factors that, at least in ordinary outpatient endoscopy material, divide subjects to subgroups with very different risks and probabilities for having coexisting peptic ulcer.

Campylobacter pylori and Barrett's esophagus

Campylobacter pylori is thought to be confined to gastric mucosa; when detected in the duodenum in association with duodenal ulceration, the organism infects only areas of gastric metaplasia. Barrett's esophagus is a metaplastic condition of the esophagus, in which areas or islands of "gastric-type" epithelium are found. To determine whether C. pylori colonized the esophagus of patients with Barrett's esophagus, we studied retrospectively 23 unselected patients who had endoscopic and biopsy evidence of Barrett's esophagus. Mucosal biopsy specimens were stained by the Warthin-Starry silver technique and reviewed by an experienced, "blinded" histopathologist. Of the 23 patients, 12 (52%) had C. pylori in the esophagus. Patients with and those without C. pylori were of similar age and gender, had similar scores for acute and chronic inflammation, and had similar lengths of tubular esophagus with metaplastic gastric mucosa. These observations suggest that C. pylori commonly infects Barrett's esophagus. The clinical importance of this finding is unknown.

Chronic erosive gastritis--a therapeutic approach with bismuth

37 patients with epigastric pain and chronic erosive gastritis underwent an open controlled therapeutic trial with bismuthsubsalicylate (BS). Group A (21 patients) was treated with BS, liquid, 4 X 314 mg for three weeks, group B (16 patients) with BS tablets, 3 X 300 mg for two weeks. A significant reduction of symptoms (p less than 0.001) and endoscopically assessed chronic erosions (p less than 0.001) was achieved in both groups. Campylobacter pylori was detected in 89% of the patients before treatment, but was absent in 78% of the patients after treatment. The histological grading of antral mucosa showed a significant reduction (p less than 0.001) of polymorphonuclear cell (PML) infiltration after two and three weeks treatment respectively. While in group A PML cells had disappeared from gastric mucosa in all but two patients, in group B 50% of the patients had some degree of PML cell infiltration left in the antral mucosa. This study confirms the beneficial effect of BS in the treatment of C. pylori associated active chronic gastritis and reemphasizes the pathogenetic role of C. pylori in this disease.