Perendoscopic gastric pH determination. Simple method for increasing accuracy in diagnosing chronic atrophic gastritis

Clinical usefulness of gastric-juice analysis in 2007: the stone that the builders rejected has become the cornerstone

BACKGROUND

Gastric juice is usually discarded during upper-GI endoscopy.

OBJECTIVE

By using a novel device, the Mt 21-42, we evaluated the potential of this important organic fluid in clinical practice, exploring its contribution to the diagnosis of Helicobacter pylori infection and atrophic gastritis of the oxyntic mucosa (AGOM).

DESIGN AND PATIENTS

A multicenter study (17,907 patients; 10 endoscopy units) estimated the frequency of diagnosis of AGOM and H pylori infection in routine endoscopic practice. A prospective study (216 patients) at 1 of these units aimed to determine the real prevalence of these conditions and the possible benefits of gastric juice analysis. We considered gastric juice pH and ammonium concentration, endoscopic and histologic features, serologic parameters for atrophy and H pylori, gastric acid secretion, and costs.

RESULTS

We found that H pylori infection and, even more markedly, AGOM were greatly underdiagnosed in routine endoscopic practice (20.1% and 0.8% vs 49.1% and 12.5% in the prospective study, respectively), because of the intrinsic limitations of the conventional tests and lack/inappropriateness of biopsy planning. Gastric-juice analysis proved to be a cheap, simple, and effective way to prevent such underdiagnosis and allowed detection of atrophic gastritis and H pylori in 96% and 98% of cases, and saved costs (cost-effectiveness ratio 209 vs 274-5047).

CONCLUSIONS

Gastric juice provided a valuable source of clinicopathologic information that, properly analyzed, allowed detection of the main risk factors for gastric cancer (H pylori and atrophic gastritis), overcoming the diagnostic limitations associated with these conditions and also producing time and cost savings.

Differential Effects of Helicobacter pylori Eradication on Oxidative DNA Damage at the Gastroesophageal Junction and at the Gastric Antrum

Background and Aim: Helicobacter pylori–associated gastritis causes accumulation of reactive oxygen species in the mucosal compartment. This prospective study evaluates DNA oxidative damage in biopsy samples obtained from both the antrum and the gastroesophageal junction (GEJ) before and after H. pylori eradication.

Patients and Methods: Thirty-two consecutive H. pylori–positive patients underwent endoscopy with multiple biopsy sampling (i.e., antrum, incisura angularis, fundus, and cardia at the GEJ). After H. pylori eradication, 32 patients underwent a checkup endoscopy (mean interval, 5.7 months); in a subgroup of 13 subjects, a third endoscopy procedure was also performed (mean interval, 18 months). Additional biopsy samples (two from the antrum and two from the GEJ) were used to assess 8-hydroxydeoxyguanosine (8OHdG) levels using both high-pressure liquid chromatography with electrochemical detector and ELISA.

Results: In the antral compartment, no significant modifications of 8OHdG levels were assessed after H. pylori eradication. Conversely, following eradication, 8OHdG levels significantly increased (high-pressure liquid chromatography with electrochemical detector, P = 0.04; ELISA method, P = 0.05) in biopsy samples taken from the GEJ, and a further increase was documented in the subgroup of patients who underwent a third endoscopy (P = 0.01). The increasing trend was more relevant in patients in whom H. pylori-cagA–positive strains were eradicated and in those affected by hiatal hernia.

Conclusions: The levels of DNA adducts in the antral mucosa are not modified by H. pylori eradication; conversely, H. pylori eradication significantly increases the oxidative adducts at the GEJ. The clinical and biological importance of this situation and whether and how it relates to a higher risk of precancerous lesions is open to debate.

Gastric antioxidant, nitrites, and mucosal lipoperoxidation in chronic gastritis and Helicobacter pylori infection

We have evaluated gastric juice pH, nitrites and vitamin C levels, mucosal glutathione, and malondialdehyde, a marker of lipid peroxidation, in patients with chronic gastritis undergoing endoscopy. Patients had chronic gastritis with (n = 28) or without (n = 60) atrophy and/or concomitant Helicobacter pylori infection. Nineteen healthy subjects, without major macroscopic or histologic changes, were included as controls. Ten subjects were studied before and after H. pylori eradication. Vitamin C levels were low in atrophic gastritis (p < 0.006) and H. pylori infection (p < 0.02). Nitrite concentrations and pH were significantly higher in atrophy (p < 0.005 and 0.0001). Glutathione turnover was higher than normal in gastritis, with higher levels of oxidized glutathione (p < 0.02). Gastric malondialdehyde levels were significantly increased by gastritis (p < 0.05) and H. pylori infection (p < 0.05). Overall, more active gastritis coincided with lower vitamin C levels and higher malondialdehyde levels. After H. pylori eradication a drop in mucosal MDA levels was observed (p = 0.04). In summary, chronic gastritis and H. pylori infection correlate with increased free-radical production, reduced gastric vitamin C levels, and increased glutathione turnover. The possible implications of these changes in the pathogenesis of gastric damage and in carcinogenesis are intriguing.

A technique for screening of achlorhydria and hypochlorhydria during upper gastrointestinal endoscopy

Measuring of the intragastric pH during upper gastrointestinal endoscopy examination was performed perendoscopically with a monocrystalline antimony electrode, which was passed through the biopsy channel of the endoscope. The procedure was easily performed, resulting in only a few minutes' delay. If the pH found was 3.5 or above, the patients were later sent for a subcutaneous pentagastrin aspiration test. There was a close correlation between the lowest intragastric pH measured via the endoscope and the lowest pH measured in the gastric juice aspirated under basal conditions (r = 0.673, p less than 0.0001). An endoscopically assessed pH of 4.0 was the lowest level above which patients with achlorhydria or hypochlorhydria were found, according to the subsequent pentagastrin test. Fifty-five per cent of the patients with a perendoscopically assessed pH of 4.0 or above were achlorhydric.

CA 19-9 determination in gastric juice: role in identifying gastric cancer and high risk patients

Gastric juice CA 19-9 levels were determined in 23 patients affected by gastric cancer, in 57 patients affected by chronic atrophic gastritis of different severities and in 55 'healthy' controls, undergoing endoscopy for upper gastrointestinal tract symptoms. Increased CA 19-9 levels were documented in chronic atrophic gastritis patients as well as in gastric cancer patients, the difference with respect to controls being statistically significant. However, there was considerable overlap between different groups. In particular, gastric cancer patients had CA 19-9 levels similar to those detected in moderate and severe chronic atrophic gastritis. CA 19-9 correlated with gastric juice pH and CEA concentration. Its values were not influenced by the patients' age or sex. In our opinion CA 19-9 gastric juice determination, although not useful in singling out patients harboring gastric neoplasia, may be used in identifying patients 'at risk' for gastric cancer and who might then be referred for more accurate investigations.