Renin-angiotensin system associated with risk of upper GI mucosal injury induced by low dose aspirin: renin angiotensin system genes' polymorphism

Comparative transcriptomics reveals highly conserved regional programs between porcine and human colonic enteric nervous system

The porcine gut is increasingly regarded as a useful translational model. The enteric nervous system in the colon coordinates diverse functions. However, knowledge of the molecular profiling of porcine enteric nerve system and its similarity to that of human is still lacking. We identified the distinct transcriptional programs associated with functional characteristics between inner submucosal and myenteric ganglia in porcine proximal and distal colon using bulk RNA and single-cell RNA sequencing. Comparative transcriptomics of myenteric ganglia in corresponding colonic regions of pig and human revealed highly conserved programs in porcine proximal and distal colon, which explained >96% of their transcriptomic responses to vagal nerve stimulation, suggesting that porcine proximal and distal colon could serve as predictors in translational studies. The conserved programs specific for inflammatory modulation were displayed in pigs with vagal nerve stimulation. This study provides a valuable transcriptomic resource for understanding of human colonic functions and neuromodulation using porcine model.

Gene Polymorphisms of the Renin-Angiotensin System and Bleeding Complications of Warfarin: Genetic-Based Machine Learning Models

This study aimed to investigate the effects of genetic variants and haplotypes in the renin–angiotensin system (RAS) on the risk of warfarin-induced bleeding complications at therapeutic international normalized ratios (INRs). Four single nucleotide polymorphisms (SNPs) of AGT, two SNPs of REN, three SNPs of ACE, four SNPs of AGTR1, and one SNP of AGTR2, in addition to VKORC1 and CYP2C9 variants, were investigated. We utilized logistic regression and several machine learning methods for bleeding prediction. The study included 142 patients, among whom 21 experienced bleeding complications. We identified a haplotype, H2 (TCG), carrying three single nucleotide polymorphisms (SNPs) of ACE (rs1800764, rs4341, and rs4353), which showed a significant relation with bleeding complications. After adjusting covariates, patients with H2/H2 experienced a 0.12-fold (95% CI 0.02–0.99) higher risk of bleeding complications than the others. In addition, G allele carriers of AGT rs5050 and A allele carriers of AGTR1 rs2640543 had 5.0- (95% CI 1.8–14.1) and 3.2-fold (95% CI 1.1–8.9) increased risk of bleeding complications compared with the TT genotype and GG genotype carriers, respectively. The AUROC values (mean, 95% CI) across 10 random iterations using five-fold cross-validated multivariate logistic regression, elastic net, random forest, support vector machine (SVM)–linear kernel, and SVM–radial kernel models were 0.732 (0.694–0.771), 0.741 (0.612–0.870), 0.723 (0.589–0.857), 0.673 (0.517–0.828), and 0.680 (0.528–0.832), respectively. The highest quartile group (≥75th percentile) of weighted risk score had approximately 12.0 times (95% CI 3.1–46.7) increased risk of bleeding, compared to the 25–75th percentile group, respectively. This study demonstrated that RAS-related polymorphisms, including the H2 haplotype of the ACE gene, could affect bleeding complications during warfarin treatment for patients with mechanical heart valves. Our results could be used to develop individually tailored intervention strategies to prevent warfarin-induced bleeding.

A novel gene associated with small bowel bleeding in patients taking low-dose aspirin

OBJECTIVE

We have previously revealed the clinical factors and genetic polymorphisms associated with gastrointestinal mucosal injury and bleeding, induced by low-dose aspirin (LDA). After performing genome-wide analysis of single nucleotide polymorphisms (SNPs) using the Drug Metabolizing Enzymes and Transporters (DMET) system among drug metabolism and transporter genes, certain SNPs were found to increase the risk for LDA-induced small bowel bleeding. The aim of this study was to identify the SNPs involved in LDA-induced small bowel bleeding.

SUBJECTS AND METHODS

Subjects were patients taking LDA, with small bowel bleeding diagnosed using capsule endoscopy. We investigated the clinical characteristics and the previously identified SNPs, that were examined by the DNA direct sequence method.

RESULTS

56 patients with bleeding and 410 controls taking LDA were enrolled. The risk factors associated with small bowel bleeding included smoking, cerebrovascular diseases, chronic renal failure, non-steroidal anti-inflammatory drug (NSAID) or anticoagulants combination, and two SNPs (CYP4F11 20043G>A (D446N) rs1060463, GSTP1 313A>G rs1695). After propensity score matching, GSTP1 rs1695 was significantly associated with small bowel bleeding.

CONCLUSION

The GSTP1 SNP may be a predictive marker for small bowel bleeding among patients taking LDA.

Biomarkers for Antiplatelet Therapies in Acute Ischemic Stroke: A Clinical Review

Stroke is one of the world's leading causes of disability and death. Antiplatelet agents are administered to acute ischemic stroke patients as secondary prevention. Clopidogrel involves biotransformation by cytochrome P450 (CYP) enzymes into an active metabolite, and single nucleotide polymorphisms (SNPs) can influence the efficacy of this biotransformation. Despite the therapeutic advantages of aspirin, there is significant inter-individual heterogeneity in response to this antiplatelet drug. In this clinical review, the recent advances in the biomarkers of antiplatelet agents in acute ischemic stroke are discussed. The studies reviewed herein highlight the clinical relevance of antiplatelet resistance, pharmacotherapy of antiplatelet agents predicting drug response, strategies for identifying aspirin resistance, pharmacogenetic variants of antiplatelet agents, miRNAs, and extracellular vesicles (EVs) as biomarkers toward the personalized approach in the management of acute ischemic stroke. The precise pathways contributing to antiplatelet resistance are not very well known but are presumably multi-factorial. It is essential to understand the clinical relevance of clopidogrel and aspirin-related single nucleotide polymorphism (SNPs) as potential predictive and prognostic biomarkers. Prasugrel is a next-generation antiplatelet agent that prevents ADP-platelet activation by binding irreversibly to P2Y12 receptor. There are sporadic reports of prasugrel resistance and polymorphisms in the Platelet endothelial aggregation receptor-1 (PEAR1) that may contribute to a change in the pharmacodynamics response. Ticagrelor, a direct-acting P2Y12-receptor antagonist, is easily absorbed and partly metabolized to major AR-C124910XX metabolite (ARC). Ticagrelor's primary active metabolite, ARC124910XX (ARC), is formed via the most abundant hepatic cytochrome P450 (CYP) enzyme, CYP3A4, and CYP3A5. The integration of specific biomarkers, genotype as well as phenotype-related data in antiplatelet therapy stratification in patients with acute ischemic stroke will be of great clinical significance and could be used as a guiding tool for more effective, personalized therapy.

Genetic polymorphisms associated with upper gastrointestinal bleeding: a systematic review

Non-variceal upper gastrointestinal bleeding (non-variceal UGIB) is a frequent and severe adverse drug reaction. Idiosyncratic responses due to genetic susceptibility to non-variceal UGIB has been suggested. A systematic review was conducted to assess the association between genetic polymorphisms and non-variceal UGIB. Twenty-one publications and 7134 participants were included. Thirteen studies evaluated genetic polymorphism in patients exposed to non-steroidal anti-inflammatory drugs, low-dose aspirin, and warfarin. Eight studies present at least one methodological problem. Only six studies clearly defined that the outcome evaluated was non-variceal UGIB. Genetic polymorphisms involved in platelet activation and aggregation, angiogenesis, inflammatory process, and drug metabolism were associated with risk of non-variceal UGIB (NOS3, COX-1; COX-2; PLA2G7; GP1BA; GRS; IL1RN; F13A1; CDKN2B-AS1; DPP6; TBXA2R; TNF-alpha; VKORC1; CYP2C9; and AGT). Further well-designed studies are needed (e.g., clear restriction to non-variceal UGIB; proper selection of participants; and adjustment of confounding factors) to provide strong evidence for pharmacogenetic and personalized medicine.

Increased risk of aspirin-induced gastric mucosal erosion in elderly Chinese men harboring SLCO1B1*1b/*1b while using aspirin and an ACEI or ARB concomitantly

Background

It is well established that long-term use of aspirin can cause gastric mucosal injury. ACEIs and ARBs are inversely related to gastric ulcer development. This study aimed to evaluate the relationship between SLCO1B1 polymorphisms, which can affect ACEI and ARB transport, and gastric mucosal erosion in elderly male Chinese patients with cardiovascular disease who use aspirin.

Methods

Patients taking aspirin and an ACEI or ARB concomitantly who had undergone endoscopic screening for gastric erosion were analyzed for SLCO1B1 polymorphisms by a TaqMan assay.

Results

The frequency of the SLCO1B1*1b/*1b diplotype (42% vs. 24%; p = 0.002) was significantly higher in the gastric mucosal erosion group than in the control group. After adjustment for significant factors, SLCO1B1*1b/*1b (OR, 2.64; 95% CI, 1.59–4.17; p < 0.05) was found to be associated with gastric mucosal erosion in aspirin users.

Conclusions

The presence of the SLCO1B1*1b/*1b diplotype may be a risk factor for aspirin-induced gastric mucosal erosion in elderly Chinese men taking aspirin and an ACEI or ARB concomitantly.

The angiotensinogen gene polymorphism, lifestyle factors, associated diseases and gastric areas of inflammatory and preneoplastic lesions in a Romanian sample of patients

The aim of our study was to evaluate the association between variant genotype of angiotensinogen (AGT) c.-58A>C, lifestyle factors and clinical factors and corporeal extension of gastric inflammatory and preneoplastic lesions.

Methods: Our study included 209 subjects who underwent a complete set of gastric biopsies, followed by genotyping. They were included to study inflammatory gastric changes and preneoplastic lesions and were grouped according to the localization of changes.

Results: No significant statistical associations were noticed between AGT c.-58A>C genotypes and the corporeal extension of the inflammation or preneoplastic injury groups. Extending preneoplastic lesions to the gastric body was associated with smoking habits (p=0.01) and additionally, there was a significant association between nicotine consumption and the body extension of preneoplastic lesions (p=0.01). The use of acenocoumarol was frequently associated with the progression of histological lesions to preneoplastic lesions (p=0.01). Compared with the wild-type AA genotype, the combined genotypes AA+CC of AGT c.-58A>C were significantly associated with the progression of inflammatory gastric lesions’ according to the regular ingested doses of nonsteroidal anti-inflammatory drugs (NSAIDs).

Conclusion: The AGT c.-58A>C polymorphism is not associated with extension of the gastric lesions. In accordance with nicotine and alcohol consumption, the acenocoumarol co-treatment and multiple cardiac pathologies are associated with the corporeal progression of these injuries. The age below 70 years and NSAIDs treatment for the patients with heterozygous AC genotype and variant homozygous CC genotype for the mentioned SNP have been associated with the corporeal extension of gastric inflammation.

Helicobacter pylori and cytokine gene variants as predictors of premalignant gastric lesions

Gastric cancer remains the third leading cause of mortality from cancer worldwide and carries a poor prognosis, due largely to late diagnosis. The importance of the interaction between Helicobacter pylori (H. pylori) infection, the main risk factor, and host-related genetic factors has been studied intensively in recent years. The genetic predisposition for non-hereditary gastric cancer is difficult to assess, as neither the real prevalence of premalignant gastric lesions in various populations nor the environmental risk factors for cancer progression are clearly defined. For non-cardiac intestinal-type cancer, identifying the factors that modulate the progression from inflammation toward cancer is crucial in order to develop preventive strategies. The role of cytokines and their gene variants has been questioned in regard to non-self-limiting H. pylori gastritis and its evolution to gastric atrophy and intestinal metaplasia; the literature now includes various and non-conclusive results on this topic. The influence of the majority of cytokine single nucleotide polymorphisms has been investigated for gastric cancer but not for preneoplastic gastric lesions. Among the investigated gene variants onlyIL10T-819C, IL-8-251, IL-18RAP917997, IL-22 rs1179251, IL1-B-511, IL1-B-3954, IL4R-398 and IL1RN were identified as predictors for premalignant gastric lesions risk. One of the most important limiting factors is the inhomogeneity of the studies (e.g., the lack of data on concomitant H. pylori infection, methods used to assess preneoplastic lesions, and source population). Testing the modifying effect of H. pylori infection upon the relationship between cytokine gene variants and premalignant gastric lesions, or even testing the interaction between H. pylori and cytokine gene variants in multivariable models adjusted for potential covariates, could increase generalizability of results.

Gastroduodenal ulcer bleeding in elderly patients on low dose aspirin therapy

AIM

To determine the clinical characteristics of elderly patients of hemorrhagic gastroduodenal ulcer on low-dose aspirin (LDA) therapy.

METHODS

A total of 1105 patients with hemorrhagic gastroduodenal ulcer treated in our hospital between January 2000 and March 2016 were grouped by age and drugs used, and these groups were compared in several factors. These groups were compared in terms of length of hospital stay, presence/absence of hemoglobin (Hb) decrease, presence/absence of blood transfusion, Forrest I, percentage of Helicobacter pylori infection, presence/absence of underlying disease, and percentage of severe cases.

RESULTS

The percentage of blood transfusion (62.6% vs 47.7 %, P < 0.001), Hb decrease (53.8% vs 40.8%, P < 0.001), and the length of hospital stay (23.5 d vs 16.7 d, P < 0.001) were significantly greater in those on drug therapy. The percentage of blood transfusion (65.3% vs 47.8%, P < 0.001), Hb decrease (54.2% vs 42.1%, P < 0.001), and length of hospital stay (23.3 d vs 17.5 d, P < 0.001) were significantly greater in the elderly. In comparison with the LDA monotherapy group, the percentage of severe cases was significantly higher in the LDA combination therapy group when elderly patients were concerned (16.1% vs 34.0%, P = 0.030). Meanwhile, among those on LDA monotherapy, there was no significant difference between elderly and non-elderly (16.1% vs 16.0%, P = 0.985).

CONCLUSION

A combination of LDA with antithrombotic drugs or non-steroidal anti-inflammatory drugs (NSAIDs) contributes to aggravation. And advanced age is not an aggravating factor when LDA monotherapy is used.

Angiotensin II receptor blocker prevents upper gastrointestinal bleeding in hypertensive patients with chronic kidney disease not on dialysis

AIMS

Investigate if angiotensin II receptor blocker (ARB) decreases risk of upper gastrointestinal bleeding (UGIB) in hypertensive patients with chronic kidney disease (CKD) not on dialysis.

METHODS

All hypertensive patients with CKD not on dialysis in outpatient department of China Medical University Hospital from 2003 to May 2013 were enrolled. The risk of UGIB was analysed using Cox proportional hazard regression.

RESULTS

A total of 2744 hypertensive CKD patients including 1515 male and 1229 female, aged 64.9 ± 13.8 years old in a median of 1.9 (0.9-3.9) years were analysed. The incidence of UGIB was 4.5 per 100 patient-years. ARB was associated with a decreased risk of UGIB (p < 0.001) with an adjusted hazard ratio (HR) of 0.533 [95% confidence interval (CI) 0.404-0.703]. A history of UGIB, Helicobacter pylori infection, diabetes, lower estimated glomerular filtration rate, elevated blood urea nitrogen and decreased serum albumin were independently associated with an increased risk of UGIB.

CONCLUSIONS

Angiotensin II receptor blocker is associated with a decreased risk of UGIB in hypertensive CKD patients not on dialysis, independent of their renal function, history of gastrointestinal bleeding and nutrition status.

Risk of peptic ulcer bleeding associated with Helicobacter pylori infection, nonsteroidal anti-inflammatory drugs, low-dose aspirin, and antihypertensive drugs: a case-control study

BACKGROUND AND AIM

The associations between antithrombotic or antihypertensive drugs and peptic ulcer bleeding (PUB) remain unknown, particularly in Asia, where Helicobacter pylori infection is prevalent. This study aims to evaluate the risks of PUB from antithrombotic drugs, angiotensin II receptor blockers (ARBs), angiotensin-converting enzyme (ACE) inhibitors, calcium channel blockers, α-blockers, and β-blockers.

METHODS

This prospective hospital-based case-control study included 230 patients with endoscopically verified PUB and 920 age and sex-matched controls (1:4) without bleeding on screening endoscopy. Adjusted odds ratios (AOR) for the risk of PUB were determined by conditional logistic regression analysis.

RESULTS

In multivariate analysis, alcohol consumption (AOR, 2.2; P < 0.001), history of peptic ulcer (AOR, 4.8; P < 0.001), H. pylori infection (AOR, 2.1; P < 0.001), comorbidity index (AOR, 1.1; P = 0.089), nonsteroidal anti-inflammatory drugs (NSAIDs) (AOR, 2.0; P = 0.025), and low-dose aspirin (AOR, 2.8; P = 0.003) increased the risk of PUB, whereas H. pylori eradication (AOR, 0.03; P < 0.001), proton pump inhibitors (PPIs) (AOR, 0.1; P < 0.001), and histamine 2-receptor antagonists (H2RA) (AOR, 0.1; P < 0.001) reduced it. No significant interactions were observed between H. pylori infection and NSAIDs use for PUB (P = 0.913). ARBs (P = 0.564), ACE inhibitors (P = 0.213), calcium channel blockers (P = 0.215), α-blockers (P = 0.810), and β-blockers (P = 0.864) were not associated with PUB.

CONCLUSION

We found that alcohol consumption, history of peptic ulcer, H. pylori infection, NSAIDs use, and low-dose aspirin use were independent risk factors for PUB, whereas H. pylori-eradication, PPIs use, and H2RA use reduced its risk. Interactions between H. pylori and NSAIDs use in PUB were not observed. No antihypertensive drug was associated with PUB.

AGT A-20C (rs5050) gene polymorphism and ulcer occurrence in patients treated with low-dose aspirin: a case-control study / Polimorfismul AGT A-20C și ulcerele gastro-duodenale la pacienții sub tratament cu aspirină în doze antiagregante: studiu caz-control

Genetic factors may play a role in prediction of gastrointestinal side effects of aspirin, one of the most used drugs worldwide. We aim to determine a possible correlation between AGT A-20C (rs5050) gene polymorphism and gastro-duodenal ulcer in patients taking low-dose aspirin, adjusted for clinical and histological characteristics.

Results. We enrolled 211 patients stratified according to AGT A-20C genotype: 122 AA, 83 AC and 6 CC patients. There were no significant differences regarding demographical and clinical parameters, except for the frequency of ulcers (4%, 8.4% respective 50%, p=0.03), endoscopic bleeding signs (12.3%, 14.5% respective 50%, p=0.0001) and the frequency of gastritis in biopsy (63.9%, 54.2% respective 16.7%, p=0.03) in genotype groups. When we compared ulcer and non-ulcer group, variant homozygous CC genotype carried an increased risk for ulcer (OR:9.66, 95% CI: 1.46-63.7, p=0.04) than AA group, as well as variant C allele compared with normal A allele (OR: 2.12, 95% CI: 1.07-4.63, p=0.04). On multivariate analysis, variant homozygous CC genotype AGT A-20C showed an OR: 12.32 (95% CI:1.40 -108.13, p=0.02) for ulcer, while H. pylori infection (OR:2.40, 95% CI:1.18 -6.54, p=0.04) and concurrent use of non-steroidal anti-inflammatory drugs (NSAIDs) (OR:1.31, 95% CI:1.07 - 2.27, p=0.05) remained predictors for ulcer in aspirin consumers.

Conclusions. Variant C allele and variant homozygous CC genotype AGT A-20C, infection with H. pylori and NSAIDs co-treatment are risk factors for gastro-duodenal ulcer in low-dose aspirin consumers. The variant homozygous CC genotype AGT A-20C patients treated with LDA are more prone to have reactive gastropathy and bleeding ulcers in a population with a high prevalence of H. pylori infection

Single nucleotide polymorphism markers for low-dose aspirin-associated peptic ulcer and ulcer bleeding

BACKGROUND AND AIM

In our previous study, the SLCO1B1 521TT genotype and the SLCO1B1*1b haplotype were significantly associated with the risk of peptic ulcer in patients taking low-dose aspirin (LDA). The aim of the present study was to investigate pharmacogenomic profile of LDA-induced peptic ulcer and ulcer bleeding.

METHODS

Patients taking 100 mg of enteric-coated aspirin for cardiovascular diseases and with a peptic ulcer or ulcer bleeding and patients who also participated in endoscopic surveillance were studied. Genome-wide analysis of single nucleotide polymorphisms (SNPs) was performed using the Affymetrix DME Plus Premier Pack. SLCO1B1*1b haplotype and candidate genotypes of genes associated with ulcer bleeding or small bowel bleeding identified by genome-wide analysis were determined using TaqMan SNP Genotyping Assay kits, polymerase chain reaction-restriction fragment length polymorphism, and direct sequencing.

RESULTS

Of 593 patients enrolled, 111 patients had a peptic ulcer and 45 had ulcer bleeding. The frequencies of the SLCO1B1*1b haplotype and CHST2 2082 T allele were significantly greater in patients with peptic ulcer and ulcer bleeding compared to the controls. After adjustment for significant factors, the SLCO1B1*1b haplotype was associated with peptic ulcer (OR 2.20, 95% CI 1.24-3.89) and CHST2 2082 T allele with ulcer bleeding (2.57, 1.07-6.17).

CONCLUSION

The CHST2 2082 T allele as well as SLCO1B1*1b haplotype may identify patients at increased risk for aspirin-induced peptic ulcer or ulcer bleeding.

Role of renin-angiotensin system and metabolites of angiotensin in the mechanism of gastric mucosal protection

Angiotensin II, the main effector of the renin-angiotensin system (RAS), is generated from the precursor angiotensinogen by the actions of renin, angiotensin-converting enzyme, chymase and various peptidases. RAS is essential in the control of blood pressure and body fluid homeostasis but their involvement in the mechanism of the protection of gastric mucosa has not been extensively studied. On the other hand, angiotensin-(1-7) which acts on the Mas receptor, exhibits a potent vasodilatory activity and attenuates the gastric lesions induced by various ulcerogens. In this review, the mechanism of RAS, the antagonists of angiotensin AT1 and AT2 receptors and angiotensin-(1-7) in formation of gastric damage is discussed with possible translating relevance to treatment modalities in the protection against gastric mucosal injury.

Therapeutic and nursing effects of Helicobacter pylori positive peptic ulcer

AIM: To investigate the therapeutic effect of quadruple therapy and comprehensive nursing care for Helicobacter pylori (H. pylori) positive peptic ulcer.

METHODS: One hundred and ninety-eight patients with H. pylori positive peptic ulcer treated at our hospital from March 2012 to December 2013 were randomly divided into two groups: an observation group (n = 99) and a control group (n = 99). The observation group was treated with the quadruple therapy (citrate bismuth potassium + amoxicillin + clarithromycin + esomeprazole) and given comprehensive nursing care, while the control group received the triple therapy (amoxicillin + clarithromycin + esomeprazole) and routine nursing care. The treatment lasted two weeks. After treatment, endoscopy was performed to observe therapeutic and nursing effects.

RESULTS: In the observation group, 28 (28.3%) patients were cured, 60 (60.1%) had significant response 5 (5.1%) had partial response, 6 (6.1%) showed no response, and the total response rate was 93.9%, and the corresponding values in the control group were 16 (16.2%), 42 (42.4%), 15 (15.1%), 26 (26.3%) and 73. 4%, respectively. The treatment effect was significantly different between the two groups (P < 0.05). At the end of treatment, 89 patients in the observation group were H. pylori negative, and the rate of H. pylori eradication was 89.9%, while in the control group, 62 were H. pylori negative, and the rate of H. pylori eradication was 62.6%. There was a significant difference between the two groups in the rate of H. pylori eradication (P < 0.05).

CONCLUSION: Quadruple therapy combined with comprehensive nursing care can effectively eradicate H. pylori and show a good therapeutic effect in the treatment of H. pylori-positive peptic ulcer.

Risk factor profiles, drug usage, and prevalence of aspirin-associated gastroduodenal injuries among high-risk cardiovascular Japanese patients: the results from the MAGIC study

BACKGROUND

Low-dose aspirin is widely used for the prevention of cardiovascular events. The prevalence of gastroduodenal injuries and the risk factor profile including gastroprotective drug therapy needs to be clarified in Japanese patients taking daily aspirin for cardioprotection.

METHODS

This Management of Aspirin-induced Gastro-Intestinal Complications (MAGIC) study was conducted with a prospective nationwide, multicenter, real-world registry of Japanese patients at high-risk of cardiovascular diseases who were taking regular aspirin (75-325 mg) for 1 month or more. All patients underwent endoscopic examination for detection of gastroduodenal ulcer and mucosal erosion. The risk factor profiles including the concurrent drug therapy were compared for those patients with gastroduodenal problems and those without.

RESULTS

Gastroduodenal ulcer and erosion were detected in 6.5, and 29.2% of the 1,454 patients receiving aspirin, respectively. H. pylori infection was associated with an increased risk for ulcer: OR 1.83 (1.18-2.88 p = 0.0082). Risk of erosion was lower with enteric-coated aspirin than with buffered aspirin: odds ratio (OR) 0.47 (0.32-0.70, p = 0.0002). Patients receiving proton pump inhibitors had lower risks for both gastroduodenal ulcer and erosion: OR 0.34 (0.15-0.68, p = 0.0050) and 0.32 (0.22-0.46, p < 0.0001), respectively. However, those receiving histamine 2-receptor antagonists had reduced risks for erosion but not for ulcer: OR 0.49 (0.36-0.68, p < 0.0001).

CONCLUSION

Gastroduodenal ulcer and erosion are common in Japanese patients taking low dose aspirin for cardioprotection. Proton pump inhibitors reduce the risk of gastroduodenal mucosal injury.

Novel single nucleotide polymorphism markers for low dose aspirin-associated small bowel bleeding

BACKGROUND

Aspirin-induced enteropathy is now increasingly being recognized although the pathogenesis of small intestinal damage induced by aspirin is not well understood and related risk factors have not been established.

AIM

To investigate pharmacogenomic profile of low dose aspirin (LDA)-induced small bowel bleeding.

METHODS

Genome-wide analysis of single nucleotide polymorphisms (SNPs) was performed using the Affymetrix DMET™ Plus Premier Pack. Genotypes of candidate genes associated with small bowel bleeding were determined using TaqMan SNP Genotyping Assay kits and direct sequencing.

RESULTS

In the validation study in overall 37 patients with small bowel bleeding and 400 controls, 4 of 27 identified SNPs: CYP4F11 (rs1060463) GG (p=0.003), CYP2D6 (rs28360521) GG (p=0.02), CYP24A1 (rs4809957) T allele (p=0.04), and GSTP1 (rs1695) G allele (p=0.04) were significantly more frequent in the small bowel bleeding group compared to the controls. After adjustment for significant factors, CYP2D6 (rs28360521) GG (OR 4.11, 95% CI. 1.62 -10.4) was associated with small bowel bleeding.

CONCLUSIONS

CYP4F11 and CYP2D6 SNPs may identify patients at increased risk for aspirin-induced small bowel bleeding.

Role of angiotensin-(1-7) in gastroprotection against stress-induced ulcerogenesis. The involvement of mas receptor, nitric oxide, prostaglandins, and sensory neuropeptides

Angiotensin-(1-7) [Ang-(1-7)] is a major vasoactive metabolite of angiotensin I (Ang I), both being important components of the renin-angiotensin system (RAS). Ang-(1-7) acting via Mas receptor was documented in kidneys, heart, brain, and gastrointestinal (GI)-tract. We studied the gastroprotective activity of exogenous Ang-(1-7) in rats exposed to water immersion and restraint stress (WRS) without or with A-779 [d-Ala7-Ang-(1-7), an antagonist of Ang-(1-7) Mas receptors], AVE 0991 (5-formyl-4-methoxy-2-phenyl-1[[4-[2-(ethylaminocarbonylsulfonamido)-5-isobutyl-3-thienyl]-phenyl]-methyl]-imidazole), the agonist of Ang-(1-7) receptor, as well as the inhibition of nitric-oxide (NO) synthase, the suppression of cyclo-oxygenase (COX)-1 (indomethacin, SC-560 [5-(4-chloro-phenyl)-1-(4-methoxyphenyl)-3-trifluoromethyl-pyrazole]), the activity COX-2 (rofecoxib), and denervation with capsaicin. The mRNA expression of constitutively expressed nitric-oxide synthase (cNOS), inducible nitric-oxide synthase (iNOS), interleukin (IL)-1β, and tumor necrosis factor (TNF)-α was analyzed by reverse transcription polymerase chain reaction. The WRS lesions were dose-dependently reduced by pretreatment with Ang-(1-7), which also caused an increase in gastric blood flow (GBF) and luminal content of NO. COX-1 and COX-2 inhibitors or L-NNA (N5-[imino(nitroamino)methyl]-L-ornithine) reversed the reduction in lesion number and the rise in GBF evoked by Ang-(1-7). Ang II augmented the WRS lesions, decreased GBF and increased the plasma IL-1β and TNF-α levels. Capsaicin denervation attenuated the reduction of Ang-(1-7)-induced gastric lesions and the rise in GBF; these effects were restored by supplementation with calcitonin gene-related peptide (CGRP). The cNOS mRNA was upregulated while iNOS, IL-1β and TNF-α mRNAs were downregulated in Ang-(1-7)-pretreated rats. We conclude that Ang-(1-7), in contrast to Ang II, which worsened WRS ulcerogenesis, affords potent gastroprotection against WRS ulcerogenesis via an increase in GBF mediated by NO, endogenous prostaglandins, sensory neuropeptides, and anti-inflammatory action involving the inhibition of proinflammatory markers iNOS, IL-1β, and TNF-α.

Risk and preventive factors of low-dose aspirin-induced gastroduodenal injuries: a comprehensive review

The risk of peptic ulcer complications, particularly bleeding, is increased in association with the use of low-dose aspirin (LDA). Risk factors for upper gastrointestinal (GI) ulcer or bleeding among LDA users include a history of prior GI events, older age, chronic renal failure, combined antithrombotic therapy and nonsteroidal anti-inflammatory drugs (NSAIDs). Helicobacter pylori and aspirin seem to be independent risk factors for peptic ulcer and bleeding. The studies report conflicting findings about the effect of H. pylori infection on NSAID-related ulcers, and proton-pump inhibitors (PPIs) seem to be superior to eradication only to prevent recurrent ulcer bleeding with LDA. Previous studies indicate that hypoacidity related to corpus atrophy, as well as taking PPIs and co-treatment with angiotensin type 1 receptor blockers (ARBs) and statins seem to reduce peptic ulcer among LDA users. In addition, the interleukin-1β (IL-1β)-511 T allele and angiotensinogen (AGT)-20 CC, which work as the high-producer allele of IL-1β and AGT, are significantly associated with ulcer or ulcer bleeding. The SLCO1B1*1b haplotype, which has the highest transport activity, may diminish the preventive effect of statins or ARBs. The data are still lacking and further prospective studies are needed to identify the specific risk or protective factors for upper GI ulcer and its complications associated with LDA.

Combination of angiotensin II receptor blockers promotes proton pump inhibitor-based healing of reflux esophagitis

BACKGROUND

Several studies have described factors associated with the failure of proton pump inhibitors (PPIs) to effect endoscopic healing of reflux esophagitis (RE), but few studies have addressed factors promoting PPI-based endoscopic healing. We performed post hoc analysis of a multicenter prospective cohort of RE patients to identify factors encouraging endoscopic healing of this disorder.

METHODS

Patients with RE received 10 or 20 mg rabeprazole for 8 weeks, and endoscopic findings before and after treatment were studied. To evaluate the effects of patient background factors on endoscopic healing, we performed multiple logistic regression analysis and determined the respective odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

A total of 454 patients who underwent endoscopy at baseline and again at week 8 were included in the analysis. After 8 weeks of treatment, improvement in endoscopic findings was observed in 94.1% (427/454) of patients, and endoscopic healing was seen in 76.7% (348/454). Multiple logistic regression analysis revealed that a combination of angiotensin II receptor blockers (ARBs) had a significant positive impact on endoscopic healing (OR 3.9, 95% CI 1.411-10.903), but no significant positive relationship was seen for other concomitant drugs such as nonsteroidal anti-inflammatory drugs and calcium channel blockers. Severe RE at baseline (OR 0.365, 95% CI 0.281-0.475) and PPI therapy prior to enrollment (OR 0.154, 95% CI 0.052-0.453) were found to have significant negative effects on endoscopic healing.

CONCLUSIONS

Concomitant use of ARBs may promote endoscopic healing of RE treated with PPIs.

Association of SLCO1B1 1b with peptic ulcer amongst Japanese patients taking low-dose aspirin

BACKGROUND

In the recent case-control study, we showed an inverse association between peptic ulcer and angiotensin type 1 receptor (AT1R) blockers (ARBs) or HMG-Co A reductase inhibitors (statins). The aim was to evaluate whether the genotypes of uptake and efflux transporters of ARBs and statins relate to the presence of peptic ulcer and/or ulcer bleeding associated with aspirin use.

METHODS

Patients taking 100mg of enteric-coated aspirin for cardiovascular diseases who also participated in endoscopic surveillance were studied. SLCO1B, ABCC2, ABCG2, and MDR1 genotypes were determined by PCR or PCR-RFLP.

RESULTS

492 patients enrolled including 78 with peptic ulcer. The frequencies of the SLCO1B1 521TT genotype were significantly higher in the ulcer group (p=0.006) compared to the controls. After adjustment for significant factors, the SLCO1B1 1b haplotype was significantly associated with peptic ulcer (OR, 3.64; 95% CI, 1.81-7.29).

CONCLUSIONS

SLCO1B1 1b haplotype may identify patients at increased risk for aspirin-induced peptic ulcer.

Role of renin-angiotensin system in gastric oncogenesis

The renin-angiotensin system (RAS) plays an important role not only in homeostasis but also in carcinogenesis. Recent epidemiological studies suggest that hypertensive patients with upregulated systemic RAS functions are at a significantly increased risk for the subsequent development of cancers with poor outcomes, and moreover that RAS inhibitors reduce tumor development, progression, and metastasis. Notably, Helicobacter pylori infection, one of the major predictors of gastric carcinogenesis, generally leads to RAS component overexpression, as exemplified by that of angiotensin I, angiotensin II, angiotensin I converting enzyme and angiotensin II receptor. Gastric mucosal RAS expression gradually increases with time after H. pylori infection with respect to the severity of inflammatory cell infiltration. Gastric carcinogenic potential is therefore considered to relate to RAS component expression levels and activities. This hypothesis is supported by findings that RAS genotypic variation can lead to high component expression levels (e.g. angiotensin I converting enzyme, chymase and angiotensinogen), and thereby increase the risk of development of gastric cancer. Thus, the RAS may be potently associated with the pathogenesis of H. pylori-related gastric carcinogenesis, and RAS inhibitors may provide tools for specifically preventing this disease.