Proton pump inhibitor therapy after Helicobacter pylori eradication may increase the risk of gastric cancer

Suppression of vacuolar-type ATPase and induction of endoplasmic reticulum stress by proton pump inhibitors

BACKGROUND

Proton pump inhibitors (PPIs), such as esomeprazole, pantoprazole, dexlansoprazole, and rabeprazole, are one of the most commonly prescribed medications. Several studies have linked the long-term use of PPIs to a potentially increased risk of gastric cancer. Therefore, this study aimed to determine the underlying mechanism of PPI-mediated gastric cancer.

METHODS

Lysosomes were isolated using immunoprecipitation. The inhibition of vacuolar-type ATPase (V-ATPase) by PPIs was assayed using a PiColorLock Gold Phosphate Detection System. PPI-induced lysosomal stress was analyzed using transcription factor EB (TFEB) nuclear translocation. PPI-induced endoplasmic reticulum (ER) stress was analyzed using the expression of protein kinase RNA-like endoplasmic reticulum kinase (PERK), inositol-requiring enzyme 1 (IRE1), and activating transcription factor 6 (ATF6). Finally, reactive oxygen species (ROS) removal was determined using the activity of superoxide dismutase (SOD).

RESULTS

PPIs caused a 70% inhibition of V-ATPase activity at 20 μM, leading to lysosomal stress through TFEB nuclear translocation; ER stress by inducing the expression of PERK, IRE1, and ATF6; and enhanced SOD activity for ROS removal.

CONCLUSION

The long-term use of PPIs inhibits lysosomal V-ATPase, leading to ER stress and ROS accumulation, which may result in an increased risk of gastric cancer. Because lysosomes and the ER are common organelles in cells, physicians prescribing PPIs for gastroesophageal reflux and peptic ulcer diseases should pay more attention to the general effects of these agents on the human body.

Dietary Factors and Gastric Intestinal Metaplasia Risk Among US Veterans

BACKGROUND

Studies on diet and gastric intestinal metaplasia (GIM) risk are lacking in US populations.

AIM

To determine the associations of dietary factors and risk of GIM among a US population with typical American diet.

METHODS

We analyzed data from a cross-sectional study of veterans attending primary care and endoscopy clinics at the Houston VA Medical Center. Patients completed a 110-item Block Food Frequency Questionnaire then underwent upper endoscopy with gastric mapping biopsies. We compared cases defined by GIM on ≥ 1 non-cardia gastric biopsy to controls without GIM. Associations of dietary factors and GIM were estimated using logistic regression models as odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Among 423 GIM cases and 1796 controls, cases were older (62.1 vs. 59.9 years) and more likely to be male (97.2% vs. 90.8%) and non-White (58.6% vs. 39.0%). GIM cases had lower fat intake (percent kcal from fat tertile 1: 43.6% vs. 33.4%) and higher carbohydrate intake (percent kcal from carbohydrate T3: 41.8% vs. 33.3%) than controls. Adjusting for age, gender, race, smoking, and Helicobacter pylori, percent kcal from carbohydrates (T3 vs. T1: OR 1.35, 95% CI 1.08-1.67), fruit intake (T3 vs. T1: OR 1.28, 95% CI 1.02-1.61), and fiber intake (T3 vs. T1: OR 1.37, 95% CI 1.04-1.80) were associated with GIM. In subgroup analyses, these associations were primarily seen in non-White patients.

CONCLUSIONS

Few dietary factors, including high carbohydrate intake, are associated with increased risk of GIM in US populations, independent of H. pylori or smoking.

Use of Acid-Suppressant Medications After Diagnosis Increases Mortality in a Subset of Gastrointestinal Cancer Patients

BACKGROUND

Acid-suppressant medications, including proton pump inhibitors (PPIs) and H₂ receptor antagonists (H₂RAs), are frequently prescribed and have been linked to increased risk of some gastrointestinal cancers.

AIMS

We examined whether post-diagnosis use of PPIs/H₂RAs is associated with the risk of mortality in gastrointestinal cancer patients.

METHODS

We used data from patients with esophageal cancer, gastric cancer, or hepatocellular carcinomas (HCCs) in the national VA Central Cancer Registry diagnosed between 2002 and 2016. We identified PPI/H₂RA prescriptions that were filled before and after cancer diagnosis and used time-dependent Cox regression models to calculate adjusted hazard ratios (HRs) and 95% CIs for mortality risk. We used a time-varying exposure to avoid immortal-time bias and a 3-month lag to reduce reverse causation. A sensitivity analysis was conducted varying the lag duration between the date of cancer diagnosis and the start of follow-up.

RESULTS

PPIs were used by the majority (54% post-diagnosis use) of patients. We found no association between post-diagnosis PPI use and cancer-specific mortality in esophageal adenocarcinoma (HR 0.93; 95% CI 0.84-1.02), esophageal squamous cell carcinoma (HR 0.99; 95% CI 0.87-1.12), or gastric cardia cancer (HR 1.04; 95% CI 0.89-1.22) patients. Post-diagnosis PPI use was, however, associated with the increased risk of cancer-specific mortality for patients with gastric non-cardia cancer (HR 1.50; 95% CI 1.29-1.74) and HCC (HR 1.31; 95% CI 1.23-1.40). The results were similar for associations with post-diagnosis use of H₂RAs. There was no association with pre-diagnosis PPI/H₂RA use.

CONCLUSION

Post-diagnosis PPI/H₂RA use was associated with the increased mortality in gastric non-cardia cancer and HCC patients.

The synergy of resveratrol and alcohol against Helicobacter pylori and underlying anti-Helicobacter pylori mechanism of resveratrol

AIMS

To determine individual antibacterial and synergistic antibacterial effects of resveratrol and alcohol against Helicobacter pylori 26695 in vitro, and to elucidate the underlying mechanism of action of resveratrol against H. pylori.

METHODS AND RESULTS

The minimum inhibitory concentrations (MICs) and time-killing curve of resveratrol and alcohol were determined. Transcriptome analysis by RNA sequencing was used to elucidate the underlying mechanism of action of resveratrol against H. pylori. Our results showed that the MICs of resveratrol and alcohol against H. pylori 26695 are about 64 μg ml^-1 and 4% (v/v) respectively. The synergy was found: resveratrol at concentration of 64 μg ml^-1 in combination with alcohol at concentration of 4% (v/v) showed >10 000-fold decrease in the mount of viable bacteria compared with resveratrol and alcohol used alone. Transcriptome analysis showed 152 genes were downregulated and 111 genes were upregulated in the presence of resveratrol. Genes involved in protein translation (17·1%), outer membrane proteins (OMPs) (9·9%) and transports (11·2%) comprise 38·2% of the downregulated genes. In comparison, genes involved in redox (13·5%), pathogenesis and motility (9·9%) and iron homeostasis (4·5%) comprise 27·9% of the upregulated genes.

CONCLUSIONS

The synergy of resveratrol and alcohol against H. pylori was found in this study. The underlying mechanism of action of resveratrol against H. pylori may be mainly attributed to its inhibitory effect on translation, OMPs, transports, ATP synthase and possible oxidative damage.

SIGNIFICANCE AND IMPACT OF THIS STUDY

Our study provides a global insight into the anti-H. pylori mechanism of resveratrol. Both resveratrol and alcohol can contribute to inhibition of ribosomes, changes in OMPs and oxidative damage, which may be the explanations of synergistic effect against H. pylori elicited by resveratrol and alcohol.