Effects of cigarette smoking on gastric ulcer formation and healing: possible mechanisms of action

Peptic ulcer disease

Annual prevalence estimates of peptic ulcer disease range between 0·12% and 1·5%. Peptic ulcer disease is usually attributable to Helicobacter pylori infection, intake of some medications (such as aspirin and non-steroidal anti-inflammatory medications), or being critically ill (stress-related), or it can be idiopathic. The clinical presentation is usually uncomplicated, with peptic ulcer disease management based on eradicating H pylori if present, the use of acid-suppressing medications-most often proton pump inhibitors (PPIs)-or addressing complications, such as with early endoscopy and high-dose PPIs for peptic ulcer bleeding. Special considerations apply to patients on antiplatelet and antithrombotic agents. H pylori treatment has evolved, with the choice of regimen dictated by local antibiotic resistance patterns. Indications for primary and secondary prophylaxis vary across societies; most suggest PPIs for patients at highest risk of developing a peptic ulcer, its complications, or its recurrence. Additional research areas include the use of potassium-competitive acid blockers and H pylori vaccination; the optimal approach for patients at risk of stress ulcer bleeding requires more robust determinations of optimal patient selection and treatment selection, if any. Appropriate continuation of PPI use outweighs most possible side-effects if given for approved indications, while de-prescribing should be trialled when a definitive indication is no longer present.

Cannabis Use Disorders Lead to Hospitalizations for Peptic Ulcer Disease: Insights From a Nationwide Inpatient Sample Analysis

Objectives

In this study, we aimed to explore the independent association between cannabis use disorders (CUD) and peptic ulcer disease (PUD)-related hospitalization, and then to delineate the demographic differences among PUD inpatients with versus without CUD.

Methodology

We conducted a cross-sectional study using the Nationwide Inpatient Sample of 50,444,133 patients. We then subgrouped them into PUD and non-PUD cohorts. We compared non-PUD and PUD cohorts using bivariate analysis to delineate the differences in demographics and comorbid risk factors (chronic lung disease, chronic kidney disease, liver disease, diabetes, chronic nonsteroidal anti-inflammatory drug use, tobacco abuse, and alcohol abuse). We used logistic regression analysis to measure the odds ratio (OR) of the association between CUD and PUD-related hospitalization.

Results

The prevalence of PUD was 0.14% (N = 70,898) among the total inpatient population. It was more prevalent in whites (65%) and males were at higher odds (OR: 1.11; P < 0.001) of being hospitalized for PUD. After controlling for potential comorbid risk factors and demographic confounders, the odds of association between CUD and PUD-related hospitalization were statistically significant (OR: 1.18; P < 0.001).

Conclusions

CUD was associated with a modest but significant increase of 18% in the likelihood of hospitalization for PUD. With the legalization of cannabis use and its increasing and problematic consumption, it is imperative to understand the impact of cannabis use on the physical health of patients and the related gastrointestinal problems.

Development and validation of a prediction rule for estimating gastric cancer risk in the Chinese high-risk population: a nationwide multicentre study

OBJECTIVE

To develop a gastric cancer (GC) risk prediction rule as an initial prescreening tool to identify individuals with a high risk prior to gastroscopy.

DESIGN

This was a nationwide multicentre cross-sectional study. Individuals aged 40-80 years who went to hospitals for a GC screening gastroscopy were recruited. Serum pepsinogen (PG) I, PG II, gastrin-17 (G-17) and anti-Helicobacter pylori IgG antibody concentrations were tested prior to endoscopy. Eligible participants (n=14 929) were randomly assigned into the derivation and validation cohorts, with a ratio of 2:1. Risk factors for GC were identified by univariate and multivariate analyses and an optimal prediction rule was then settled.

RESULTS

The novel GC risk prediction rule comprised seven variables (age, sex, PG I/II ratio, G-17 level, H. pylori infection, pickled food and fried food), with scores ranging from 0 to 25. The observed prevalence rates of GC in the derivation cohort at low-risk (≤11), medium-risk (12-16) or high-risk (17-25) group were 1.2%, 4.4% and 12.3%, respectively (p<0.001).When gastroscopy was used for individuals with medium risk and high risk, 70.8% of total GC cases and 70.3% of early GC cases were detected. While endoscopy requirements could be reduced by 66.7% according to the low-risk proportion. The prediction rule owns a good discrimination, with an area under curve of 0.76, or calibration (p<0.001).

CONCLUSIONS

The developed and validated prediction rule showed good performance on identifying individuals at a higher risk in a Chinese high-risk population. Future studies are needed to validate its efficacy in a larger population.

A prospective study of the clinical outcomes and prognosis associated with comorbid COPD in the atrial fibrillation population

Background

Patients with COPD are at higher risk of presenting with atrial fibrillation (AF). Information about clinical outcomes and optimal medical treatment of AF in the setting of COPD remains missing. We aimed to describe the prevalence of COPD in a sizeable cohort of real-world AF patients belonging to the same healthcare area and to examine the relationship between comorbid COPD and AF prognosis.

Methods

Prospective analysis performed in a specific healthcare area. Data were obtained from several sources within the “data warehouse of the Galician Healthcare Service” using multiple analytical tools. Statistical analyses were completed using SPSS 19 and STATA 14.0.

Results

A total of 7,990 (2.08%) patients with AF were registered throughout 2013 in our healthcare area (n=348,985). Mean age was 76.83±10.51 years and 937 (11.7%) presented with COPD. COPD patients had a higher mean CHA₂DS₂-VASc (4.21 vs 3.46; P=0.02) and received less beta-blocker and more digoxin therapy than those without COPD. During a mean follow-up of 707±103 days, 1,361 patients (17%) died. All-cause mortality was close to two fold higher in the COPD group (28.3% vs 15.5%; P<0.001). Independent predictive factors for all-cause mortality were age, heart failure, diabetes, previous thromboembolic event, dementia, COPD, and oral anticoagulation (OA). There were nonsignificant differences in thromboembolic events (1.7% vs 1.5%; P=0.7), but the rate of hemorrhagic events was significantly higher in the COPD group (3.3% vs 1.9%; P=0.004). Age, valvular AF, OA, and COPD were independent predictive factors for hemorrhagic events. In COPD patients, age, heart failure, vasculopathy, lack of OA, and lack of beta-blocker use were independent predictive factors for all-cause mortality.

Conclusion

AF patients with COPD have a higher incidence of adverse events with significantly increased rates of all-cause mortality and hemorrhagic events than AF patients without COPD. However, comorbid COPD was not associated with differences in cardiovascular death or stroke rate. OA and beta-blocker treatment presented a risk reduction in mortality while digoxin use exerted a neutral effect.

Acid and the basis for cellular plasticity and reprogramming in gastric repair and cancer

Subjected to countless daily injuries, the stomach still functions as a remarkably efficient digestive organ and microbial filter. In this Review, we follow the lead of the earliest gastroenterologists who were fascinated by the antiseptic and digestive powers of gastric secretions. We propose that it is easiest to understand how the stomach responds to injury by stressing the central role of the most important gastric secretion, acid. The stomach follows two basic patterns of adaptation. The superficial response is a pattern whereby the surface epithelial cells migrate and rapidly proliferate to repair erosions induced by acid or other irritants. The stomach can also adapt through a glandular response when the source of acid is lost or compromised (that is, the process of oxyntic atrophy). We primarily review the mechanisms governing the glandular response, which is characterized by a metaplastic change in cellular differentiation known as spasmolytic polypeptide-expressing metaplasia (SPEM). We propose that the stomach, like other organs, exhibits marked cellular plasticity: the glandular response involves reprogramming mature cells to serve as auxiliary stem cells that replace lost cells. Unfortunately, such plasticity might mean that the gastric epithelium undergoes cycles of differentiation and de-differentiation that increase the risk of accumulating cancer-predisposing mutations.

Chronic obstructive pulmonary disease is associated with increased recurrent peptic ulcer bleeding risk

BACKGROUND

The association between chronic obstructive pulmonary disease (COPD) and the risk of recurrent peptic ulcer bleeding (PUB) remains unclear. In this study, we compared the risk of recurrent PUB between patients with and those without COPD.

METHODS

Using the Taiwan National Health Insurance Research Database, we first selected patients newly diagnosed with PUB in 2002-2009. Two groups comprising 13,732 COPD cases and 13,732 non-COPD matched controls were created using propensity score matching, thereby making the differences in basic demographics, medication use, and disease conditions between the two groups negligible. Cox proportional hazard regression was used to evaluate the risk of recurrent PUB during the follow-up period.

RESULTS

The cumulative recurrence rate of PUB was significantly higher in the patients with COPD than in the non-COPD matched controls (2years: 10.8% vs 9.3%; 6years: 18.3% vs 15.7%, P all <0.05), with an adjusted hazard ratio (HR) of 1.17 (95% confidence interval [CI], 1.08-1.26, P<0.001) and 1.19 (95% CI, 1.12-1.26, P<0.001) within 2-year and 6-year follow-ups, respectively. Patients with COPD using steroids were at a marginally higher risk of recurrent PUB than those who did not use steroids. Multivariate stratified analysis revealed similar results in many subgroups.

CONCLUSIONS

The risk of recurrent PUB is higher in patients with COPD than in patients without COPD.

A systematic approach for the diagnosis and treatment of idiopathic peptic ulcers

An idiopathic peptic ulcer is defined as an ulcer with unknown cause or an ulcer that appears to arise spontaneously. The first step in treatment is to exclude common possible causes, including Helicobacter pylori infection, infection with other pathogens, ulcerogenic drugs, and uncommon diseases with upper gastrointestinal manifestations. When all known causes are excluded, a diagnosis of idiopathic peptic ulcer can be made. A patient whose peptic ulcer is idiopathic may have a higher risk for complicated ulcer disease, a poorer response to gastric acid suppressants, and a higher recurrence rate after treatment. Risk factors associated with this disease may include genetic predisposition, older age, chronic mesenteric ischemia, smoking, concomitant diseases, a higher American Society of Anesthesiologists score, and higher stress. Therefore, the diagnosis and management of emerging disease should systematically explore all known causes and treat underlying disease, while including regular endoscopic surveillance to confirm ulcer healing and the use of proton-pump inhibitors on a case-by-case basis.

Body Mass Index and Smoking Affect Thioguanine Nucleotide Levels in Inflammatory Bowel Disease

INTRODUCTION

Optimal levels of the thiopurine metabolite, 6-thioguanine nucleotides [6-TGN] correlate with remission of inflammatory bowel disease [IBD]. Apart from variations in the thiopurine methyl transferase [TPMT] gene, little is known about other predictors of 6-TGN levels. Obesity adversely affects response to infliximab and adalimumab and clinical course in IBD, but little is known about the interaction of thiopurines and obesity. We investigated the relationship between body mass index [BMI] and 6-TGN levels and sought to examine other predictors of 6-TGN levels.

METHODS

This retrospective cohort study included patients with concurrent measurements of 6-TGN and BMI. The association between 6-TGN and clinical variables including BMI was estimated using a multivariable linear regression model.

RESULTS

Of 132 observations, 77 [58%] had Crohn's disease and 55 [42%] ulcerative colitis. BMI, smoking, and TPMT levels were associated with 6-TGN levels in multivariable analysis. Every 5kg/m(2) increase in BMI was associated with an 8% decrease in 6-TGN (0.92; 95% confidence interval [CI] 0.87-0.98; p = 0.009). Smokers had higher 6-TGN levels in comparison with non-/ex-smokers [1.43; 95% CI 1.02-2.02; p = 0.041]. Patients with intermediate TPMT had higher 6-TGN compared to those with normal levels [2.13; 95% CI 1.62-2.80; p < 0.001]. Obese patients were more likely to have sub-therapeutic 6-TGN levels and a higher methyl mercaptopurine nucleotide [MMPN/TGN] ratio despite a similar dose of thiopurines.

CONCLUSIONS

Active smoking and intermediate TPMT values were associated with higher 6-TGN levels but increasing BMI resulted in lower 6-TGN and higher MMPN levels. This may explain the worse outcome that has been reported previously in obese IBD subjects.

Xanthine oxidoreductase is a critical mediator of cigarette smoke-induced endothelial cell DNA damage and apoptosis

Cigarette smoke (CS) exposure is unquestionably the most frequent cause of emphysema in the United States. Accelerated pulmonary endothelial cell (EC) apoptosis is an early determinant of lung destruction in emphysema. One of the pathogenic causes of emphysema is an alveolar oxidant and antioxidant imbalance. The enzyme xanthine oxidoreductase (XOR) has been shown to be a source of reactive oxygen species (ROS) in a multitude of diseases (S. Sakao et al., FASEB J.21, 3640-3652; 2007). The contribution of XOR to CS-induced apoptosis is not well defined. Here we demonstrate that C57/bl6 mice exposed to CS have increased pulmonary XOR activity and protein levels compared to filtered-air-exposed controls. In addition, we demonstrate that primary pulmonary human lung microvascular endothelial cells exposed to cigarette smoke extract undergo increased rates of caspase-dependent apoptosis that are reliant on XOR activity, ROS production, and p53 function/expression. We also demonstrate that exogenous XOR is sufficient to increase p53 expression and induce apoptosis, suggesting that XOR is an upstream mediator of p53 in CS-induced EC apoptosis. Furthermore, we show that XOR activation results in DNA double-strand breaks that activate the enzyme ataxia telangiectasia mutated, which phosphorylates histone H2AX and upregulates p53. In conclusion, CS increases XOR expression, and the enzyme is both sufficient and necessary for p53 induction and CS-induced EC apoptosis.

Review article: Helicobacter pylori-negative duodenal ulcer disease

BACKGROUND

Helicobacter pylori infection rates in duodenal ulcer (DU) patients may be lower than previously estimated.

AIM

To review the real prevalence of H. pylori-negative DUs and its possible causes.

METHODS

Bibliographical searches in MEDLINE looking for the terms 'H. pylori' and 'duodenal ulcer'.

RESULTS

Mean prevalence of H. pylori infection in DU disease, calculated from studies published during the last 10 years including a total of 16 080 patients, was 81%, and this figure was lower (77%) when only the last 5 years were considered. Associations with H. pylori-negative DU were: (1) False negative results of diagnostic methods, (2) NSAID use (21% in studies with <90% infection rate), (3) Complicated DU (bleeding, obstruction, perforation), (4) Smoking, (5) Isolated H. pylori duodenal colonization, (6) Older age, (7) Gastric hypersecretion, (8) Diseases of the duodenal mucosa, (9) Helicobacter'heilmanii' infection and (10) Concomitant diseases.

CONCLUSION

In patients with H. pylori-negative DU disease, one should carefully confirm that the assessment of H. pylori status is reliable. In truly H. pylori-negative patients, the most common single cause of DU is, by far, the use of NSAIDs. Ulcers not associated with H. pylori, NSAIDs or other obvious causes should, for the present, be viewed as 'idiopathic'. True idiopathic DU disease only exceptionally exists.

Bisphosphonate increases risk of gastroduodenal ulcer in rheumatoid arthritis patients on long-term nonsteroidal antiinflammatory drug therapy

BACKGROUND

Rheumatoid arthritis (RA) patients are at increased risk of peptic ulcers (PU) induced by nonsteroidal antiinflammatory drugs (NSAIDs). However, the impact of potential drug interactions on the development of PU has yet to be determined in a daily clinical setting. The aim was to estimate the clinical important interactions for PU presented by comedication in Japanese RA outpatients on long-term NSAID treatment.

METHODS

This retrospective cohort study enrolled 196 consecutive RA outpatients on NSAID medication for at least 3 months. Potential risk factors for endoscopic PU were analyzed in RA outpatients on longterm NSAID treatment.

RESULTS

PU incidence was 31% with bisphosphonate co-therapy and 17% without the co-therapy. PU incidence was only 5% in subjects with proton pump inhibitors (PPI) or prostaglandin E1 analogues (PG) co-therapy, 14% with histamine-H(2) receptor antagonists(H2RA) co-therapy, and 27% without anti-ulcer agents. In multivariate logistic regression analysis, bisphosphonate co-therapy remained a significant risk factor for PU (OR, 2.29; 95% CI, 1.09-4.81). Other risk factors for ulcer development were advanced age (greater than 60 years) and smoking (OR, 2.58; 95% CI, 1.03-6.49 and OR, 2.71; 95% CI, 1.13-5.53, respectively.) Factors that significantly reduced the incidence of PU were H2RA or PPI/PG cotherapies (OR, 0.29; 95% CI, 0.12-0.68.).

CONCLUSIONS

Bisphosphonate co-therapy as well as advanced age and smoking was found to be a significant risk factor in PU, while co-therapies of standard-dose H2RA or PPI/PG proved effective in preventing PU in Japanese RA patients on long-term NSAID treatment.

Size of the peptic ulcer in Helicobacter pylori-positive patients: association with the clinical and histological characteristics

OBJECTIVE

Based on a large trial of Helicobacter pylori-positive peptic ulcer patients, we studied whether the size of the ulcer, along with other clinical and histological characteristics, has any effect on healing. We also studied the clinical and endoscopic characteristics associated with size of the peptic ulcer.

MATERIAL AND METHODS

A total of 333 consecutive patients with H. pylori infection and peptic ulcer were enrolled (mean age 54.8+/-12.7 years). Location of the ulcer was recorded by gastroscopy and the presence of H. pylori was assured by rapid urease test, histology and by serum H. pylori IgG and IgA antibody measurement. The diameter of the ulcer was measured by placing the opened biopsy forceps (7 mm) beside it. Biopsy specimens were examined in accordance with the Sydney system.

RESULTS

Mean size of the peptic ulcer was 13.2+/-8.3 in corpus, 11.3+/-5.3 in antrum, 13.8+/-7.8 in angulus, 9.5+/-5.3 in prepylorus and 9.2+/-4.7 mm in duodenum (duodenal versus gastric type; p<0.05). Average size of the ulcers was 9.4+/-5.3 mm in patients with Forrest III type and 11.5+/-6.8 in other types (p<0.05). Patients who were >or=50 years of age, currently smoking, or who had corpus-predominant chronic gastritis or atrophic gastritis, had larger ulcers than others. Size of index ulcers, successful eradication of H. pylori and the presence of atrophic gastritis were independent factors for healing. The odds ratio was 11.5 (95% CI 3.3-40.5; p<0.01) for eradication of H. pylori, 3.5 (95% CI 1.1-11.2; p<0.05) for size of the index ulcer (<or=10 mm versus >10 mm) and 3.4 (95% CI 1.2-9.8; p<0.05) for atrophic gastritis versus no atrophy.

CONCLUSIONS

Size of the peptic ulcer, successful H. pylori eradication and atrophic gastritis were independent factors for the healing of peptic ulcers. A number of clinical and endoscopic variables (age, current smoking, corpus-predominant gastritis, Forrest classification) were associated with size of the peptic ulcer in H. pylori-positive patients.

New method of evaluating gastric mucosal blood flow by ultrasound

OBJECTIVE

Evaluation of gastrointestinal blood flow is important. However, a non-invasive measurement method has not yet been established. The aim of this study was to compare measurement of normal gastric mucosal blood flow by advanced dynamic flow (ADF) flash echo imaging (FEI) with intravenous Levovist with measurement by laser Doppler flowmetry (LDF) to clarify the usefulness of ADF-FEI and thereby consider its feasibility as a non-invasive gastric mucosal blood flow measurement method.

MATERIAL AND METHODS

Measurements were obtained in 25 beagle dogs (8-month-old males, body-weight, 10.6+/-1.3 kg, mean+/-SD). After insertion of a gastrointestinal endoscope, gastric mucosal blood flow at the greater curvature of the corpus was measured by LDF, and images of gastric mucosal blood flow were obtained by ADF-FEI (frequency; 4.7 MHz) with intravenous injection of Levovist (30 mg/kg). ADF-FEI images were transferred to a personal computer. A region of interest was set on the mucosa of the greater curvature of the corpus, and a time intensity curve (TIC) was plotted from the measured echo intensities. The area under the curve (AUC) calculated from the TIC and the median flow determined by LDF were analyzed and compared.

RESULTS

Evaluation of normal gastric mucosal blood flow by ADF-FEI was possible in all animals. There was a strong, significant correlation between gastric mucosal blood flow measured by LDF and the AUC obtained by ADF-FEI (r=0.869, p<0.0001).

CONCLUSIONS

Gastric mucosal blood flow can be accurately measured by ADF-FEI with intravenous Levovist injection.

Impact of sidestream whole smoke solutions on the outcome of wound repair and related angiogenesis

Wound angiogenesis is essential to support the regenerating tissue and any setback in angiogenesis may result in retarded wound repair. Cigarette smoking causes numerous adverse effects, some of which are associated with poor healing. The current experiment was carried out to elucidate the possible detrimental effects of sidestream whole smoke solutions (SSWSS) on wound healing and related angiogenesis, using a well-defined chicken dorsum excision wound assay. Gross, histopathologic, SEM and computer based 3D image-probing modalities were utilized to quantify different detrimental effects of SSWSS on the fundamental processes of wound healing. A total of 160 chicks, aged 1 week, divided in eight groups were topically exposed for 8 days to SSWSS with different nicotine concentrations. At day 6 and day 8 post-wounding, very highly significant reduction (P<0.001) in wound closure was observed among all SSWSS treated groups. Histological and SEM evaluation of SSWSS treated wounds unveiled deteriorated dermal matrix, delayed re-epithelialization and retarded neovascularization. Moreover, image-probing exploration of SSWSS treated wounds also divulge a very highly significant decrease (P<0.001) in angular spectrum, Sa, Sy and Sci, at day 6 post-wounding. Our study suggests that the cumulative effect of different components of SSWSS has a negative impact on wound healing and related angiogenesis. Furthermore, our study demonstrates the effects that can contribute to abnormal healing and may explain why people who are consistently exposed to sidestream smoke suffer from slow healing and excessive scarring of wounds, much like the smokers themselves.

Association of laryngeal cancer with previous gastric resection

OBJECTIVE

To investigate the association between gastric surgery and cancer of the larynx.

SUMMARY BACKGROUND DATA

Biliary reflux is frequent after gastric surgery and may reach the proximal segment of the esophagus and the larynx. It is possible that duodenal content (consisting in bile acids, trypsin), together with pepsin and acid residues when gastric resection is partial, may cause harmful action on the multistratified epithelium of the larynx.

METHODS

A retrospective case-control study on subjects admitted between January 1987 and May 2002 in the same hospital in Rome was carried out. The study included 828 consecutive patients with laryngeal cancer (cases) and 825 controls with acute myocardial infarction. Controls were randomly sampled out of a total of 10,000 and matched with cases for age, sex, and year of admission. Logistic regression models were used to assess the role of gastric resection in determining laryngeal cancer risk while controlling for potential confounding factors.

RESULTS

Previous gastrectomy was reported by 8.1% of cases and 1.8% of the controls (P < 0.0001). A 4-fold association emerged between gastric surgery and laryngeal cancer risk (adjusted OR = 4.3, 95% CI: 2.4-7.9). The risk appeared strongly increased 20 years after surgery (OR = 14.8, 95% CI: 3.4-64.6). Heavy alcohol drinking (OR = 2.5, 95% CI: 1.8-3.5), smoking (OR = 4.7, 95% CI: 3.3-6.7), and blue-collar occupation (OR = 4.6, 95% CI: 3.2-6.7) were all independently associated with the risk of laryngeal cancer.

CONCLUSIONS

Previous gastric surgery is associated with an increased risk of laryngeal cancer. A periodic laryngeal examination should be considered in long-term follow-up of patients with gastric resection.

Smoking and the pathogenesis of gastroduodenal ulcer--recent mechanistic update

Peptic ulcer is a common disorder of gastrointestinal system and its pathogenesis is multifactorial, where smoking and nicotine have significant adverse effects. Smoking and chronic nicotine treatment stimulate basal acid output which is more pronounced in the smokers having duodenal ulcer. This increased gastric acid secretion is mediated through the stimulation of H2-receptor by histamine released after mast cell degranulation and due to the increase of the functional parietal cell volume or secretory capacity in smokers. Smoking and nicotine stimulate pepsinogen secretion also by increasing chief cell number or with an enhancement of their secretory capacity. Long-term nicotine treatment in rats also significantly decreases total mucus neck cell population and neck-cell mucus volume. Smoking also increases bile salt reflux rate and gastric bile salt concentration thereby increasing duodenogastric reflux that raises the risk of gastric ulcer in smokers. Smoking and nicotine not only induce ulceration, but they also potentiate ulceration caused by H. pylori, alcohol, nonsteroidal anti-inflammatory drugs or cold restrain stress. Polymorphonuclear neutrophils (PMN) play an important role in ulcerogenesis through oxidative damage of the mucosa by increasing the generation of reactive oxygen intermediates (ROI), which is potentiated by nicotine and smoking. Nicotine by a cAMP-protein kinase A signaling system elevates the endogenous vasopressin level, which plays an aggressive role in the development of gastroduodenal lesions. Smoking increases production of platelet activating factor (PAF) and endothelin, which are potent gastric ulcerogens. Cigarette smoking and nicotine reduce the level of circulating epidermal growth factor (EGF) and decrease the secretion of EGF from the salivary gland, which are necessary for gastric mucosal cell renewal. Nicotine also decreases prostaglandin generation in the gastric mucosa of smokers, thereby making the mucosa susceptible to ulceration. ROI generation and ROI-mediated gastric mucosal cell apoptosis are also considered to be important mechanism for aggravation of ulcer by cigarette smoke or nicotine. Both smoking and nicotine reduce angiogenesis in the gastric mucosa through inhibition of nitric oxide synthesis thereby arresting cell renewal process. Smoking or smoke extract impairs both spontaneous and drug-induced healing of ulcer. Smoke extract also inhibits gastric mucosal cell proliferation by reducing ornithine decarboxylase activity, which synthesises growth-promoting polyamines. It is concluded that gastric mucosal integrity is maintained by an interplay of some aggressive and defensive factors controlling apoptotic cell death and cell proliferation and smoking potentiates ulcer by disturbing this balance.

Risk factors for upper gastrointestinal bleeding among end-stage renal disease patients

BACKGROUND

The risk of upper gastrointestinal bleeding (UGIB) is increased among end-stage renal disease (ESRD) patients compared to the general population. However, correlates of UGIB among ESRD patients remain unknown. We conducted a cohort study of dialysis patients to ascertain risk factors for UGIB.

METHODS

Data from the United States Renal Data System Dialysis Morbidity and Mortality Studies, Waves 2-4 were used to identify risk factors for incident UGIB among ESRD patients. First hospitalizations for UGIB were identified using hospital diagnosis codes between 12/31/93 and 12/31/99. Cox regression was used to estimate the association between predictors of interest and first diagnosis of UGIB.

RESULTS

Cases of UGIB (698) were observed over 30648 patient years of follow-up. Before adjustment for confounding factors, increasing age, diabetes, former and current smoking, cardiovascular disease (CVD), lower serum albumin, malnutrition, and inability to ambulate independently were associated with an increased risk of UGIB, while African Americans and transplant patients had a lower risk of UGIB. After adjustment, African American race was associated with a lower risk of UGIB (RR = 0.90; 0.82, 0.98), while current smoking (RR = 1.11; confidence interval 1.03, 1.19), history of CVD (RR = 1.32; 1.10, 1.59), and inability to ambulate independently (RR = 1.32; 1.07, 1.63) were associated with a higher risk of UGIB. Age, gender, diabetes, lower serum albumin, nourishment, treatment modality, aspirin use, nonsteroidal anti-inflammatory drug (NSAID) use, and antiplatelet or anticoagulant medication use were not found to be significantly related to the risk of UGIB after adjustment for potential confounding factors.

CONCLUSION

CVD, current smoking, and risk factors suggesting more disability are associated with a greater risk of UGIB among patients with ESRD.

Upregulation of xanthine oxidase by tobacco smoke condensate in pulmonary endothelial cells

Tobacco smoking has been causally linked to the development of chronic obstructive pulmonary disease. It has been reported that the reactive oxygen species (ROS)- generating enzyme xanthine dehydrogenase/oxidase (XO) is increased in smoking-related stomach ulcers and that gastric mucosal damage caused by tobacco smoke can be blocked by the XO inhibitor allopurinol. In order to test the hypothesis that tobacco may cause the upregulation of XO in the lung, cultured rat pulmonary microvascular endothelial cells were exposed to tobacco smoke condensate (TSC). TSC at a concentration of 20 microg/mL significantly upregulated XO activity after 24 h of exposure. Longer exposure (1 week) to a lower concentration of TSC (2 microg/mL) also caused an increase in XO activity. Unlike hypoxia, TSC treatment did not alter the phosphorylation of XO. However, TSC treatment increased XO mRNA expression and the XO gene promoter activity. Furthermore, actinomycin D blocked the activation of XO by TSC. In conclusion, our results indicate that tobacco smoke condensate causes upregulation of XO transcription and activity.

Nicotine suppresses gastric wound repair via the inhibition of polyamine and K(+) channel expression

Nicotine is one of the most representative components in cigarette smoke leading to gastric ulceration. Both ornithine decarboxylase and potassium ion (K(+)) channels are essential for cell growth and wound repair. The aim of the present study is to elucidate the causative relationship of these two factors during wound healing and the influence of nicotine on this healing process in rat gastric mucosal epithelial cells (RGM-1). Nicotine markedly inhibited cell migration and proliferation in RGM-1 cells. The latter effect was significantly antagonized by a nicotinic receptor blocker, mecamylamine. Nicotine also suppressed ornithine decarboxylase activity significantly. Our data showed that inhibition of cell proliferation and ornithine decarboxylase activity by nicotine was accompanied with a reduction in K(+) channel protein expression, all of which were significantly alleviated by spermidine pretreatment. These results suggested that there was a cause/effect link between ornithine decarboxylase and K(+) channel on wound repair. Nicotine in cigarette smoke inhibited this healing process and delayed wound repair in gastric epithelial cells.

Risk factors for hospitalized upper or lower gastrointestinal tract bleeding in treated hypertensives

BACKGROUND

We examined risk factors for hospitalized gastrointestinal bleeding among health maintenance organization (HMO) members with hypertension.

METHODS

Case subjects (n = 199) were patients with hypertension hospitalized for confirmed gastrointestinal bleeding in 1992-1994. Control hypertensive subjects (n = 821) were selected from ongoing studies. Medical records and computerized pharmacy data were used to assess risk factors. Adjusted relative risks (RRs) were estimated using logistic regression models.

RESULTS

In multivariate-adjusted models, significant risk factors for upper gastrointestinal bleeding (n = 111 cases) were hepatic disease (RR = 2.85), elevated creatinine (RR = 2.45), nonsteroidal anti-inflammatory drug use (RR = 2.28), smoking (RR = 1.93), cardiovascular disease (RR = 1.89), and physical inactivity (RR = 1.70). Risk factors for lower gastrointestinal bleeding (n = 43 cases) in multivariate-adjusted analyses were anticoagulant or thrombolytic therapy (RR = 3.80), elevated creatinine (RR = 2.31), and physical inactivity (RR = 2.10).

CONCLUSIONS

This study confirmed several known risk factors for hospitalized gastrointestinal bleeding, including hepatic disease, renal dysfunction, and medication use, and also identified smoking and physical inactivity as independent risk factors. The magnitude of the relative risks associated with these behavioral factors suggests that lifestyle modification may substantially reduce the risk of gastrointestinal bleeding.

Cigarette smoke extracts delay wound healing in the stomach: involvement of polyamine synthesis

The association between cigarette smoking and peptic ulcer diseases has been well established. Ornithine decarboxylase (ODC) is crucial for the gastroprotective and mucosal growth promoting effects in gastric ulcer healing. The aim of this study is to elucidate the possible mechanism of how inhibition of ODC activity is involved in the delay of ulcer healing, if any, by cigarette smoke extracts (CSE). CSE were fractionated into chloroform extract (CE) and ethanol extract (EE). In in vivo study, rats with acetic acid-induced ulcers were given CE or EE intragastrically (2.5 or 5 mg/kg) once daily for 3 days. Ulcer sizes were significantly larger after CE or EE administration, followed by an increase in myeloperoxidase activity and a reduction in cell proliferation. However, both CSE stimulated the number of microvessels following the increase of basic fibroblast growth factor. In in vitro studies, the effect of CE or EE (10, 40, or 100 microg/ml) on cell migration and cell proliferation were measured using an in vitro wound model and [(3)H]-thymidine incorporation assay, respectively. Both CSE delayed cell migration and decreased cell proliferation, which were accompanied with a reduction in ODC activity. Exogenous spermidine (5 or 10 microM) could reverse the inhibitory action on cell proliferation and ODC activity induced by CSE. In conclusion, both CSE significantly delayed ulcer healing as a result of reduction in cell proliferation and cell migration. All these effects are, in part, related to the reduction of polyamine synthesis.

Clinical and endoscopic characteristics of non-Helicobacter pylori, non-NSAID duodenal ulcers: a long-term prospective study

BACKGROUND

The proportion of duodenal ulcers not associated with Helicobacter pylori infection or the use of non-steroidal anti-inflammatory drugs (NSAIDs) is increasing.

AIM

To identify the clinical and endoscopic characteristics of non-H. pylori, non-NSAID duodenal ulcers.

METHODS

Clinical and endoscopic data and H. pylori status were prospectively collected from consecutive patients who underwent upper endoscopy from 1997 to 1999. Patients with duodenal ulcers were identified, and those with non-H. pylori, non-NSAID duodenal ulcers were analysed further.

RESULTS

A total of 11 717 upper endoscopies were performed in 8344 patients. Of these, 1153 (14%) had duodenal ulcers. Of 599 patients with active ulcers and known H. pylori status, 104 (17%) had ulcers not associated with H. pylori or the use of NSAIDs, 393 (66%) had ulcers associated with H. pylori alone, 51 (8.5%) had ulcers associated with the use of NSAIDs alone and 51 (8.5%) had ulcers associated with both. Multivariate logistic regression analysis revealed that the presence of concomitant diseases (odds ratio=15.0; 95% confidence interval, 8.64-25.9; P < 0.001) and the absence of epigastric pain/discomfort (odds ratio=0.52; 95% confidence interval, 0.29-0.91; P=0.022) were independent predictors for non-H. pylori, non-NSAID duodenal ulcers.

CONCLUSIONS

Non-H. pylori, non-NSAID duodenal ulcers exhibit certain distinct clinical and endoscopic characteristics. The presence of concomitant diseases is an important predictive factor.

Risk factors for hospitalized gastrointestinal bleeding among older persons. Cardiovascular Health Study Investigators

OBJECTIVES

We sought to estimate the incidence of hospitalization for upper and lower gastrointestinal bleeding among older persons and to identify independent risk factors.

DESIGN

Prospective cohort study.

SETTING

The Cardiovascular Health Study (CHS).

PARTICIPANTS

5,888 noninstitutionalized men and women age 65 years or older in four U.S. communities enrolled in the CHS.

MEASUREMENTS

Gastrointestinal bleeding events during the period 1989 through 1998 were identified using hospital discharge diagnosis codes and confirmed by medical records review. Risk-factor information was collected in a standardized fashion at study baseline and annually during follow-up.

RESULTS

Among CHS participants (mean baseline age 73.3 years, 42% male), the incidence of hospitalized gastrointestinal bleeding was 6.8/1,000 person-years. In multivariate analyses, advanced age, male sex, unmarried status, cardiovascular disease, difficulty with daily activities, use of multiple medications, and use of oral anticoagulants were independent risk factors. Compared with nonsmokers, subjects who smoked more than half a pack per day had a multivariate-adjusted hazard ratio (HR) of 2.14 (95% confidence interval [CI] = 1.22-3.75) for upper gastrointestinal bleeding and a multivariate-adjusted HR of 0.21 (95% CI = 0.03-1.54) for lower gastrointestinal bleeding. Aspirin users did not have an elevated risk of upper gastrointestinal bleeding (HR = 0.76, 95% CI = 0.52-1.11), and users of other nonsteroidal anti-inflammatory drugs had a HR of 1.54 (95 % CI = 0.99-2.36). Low ankle-arm systolic blood pressure index was associated with higher risk of gastrointestinal bleeding among subjects with clinical cardiovascular disease but not among those without clinical cardiovascular disease.

CONCLUSION

This study identifies risk factors for gastrointestinal bleeding, such as disability, that may be amenable to modification. The findings will help clinicians to identify older persons who are at high risk for gastrointestinal bleeding.

Nonsteroidal anti-inflammatory drugs and the gastrointestinal tract. Mechanisms of protection and healing: current knowledge and future research

The resistance of the gastric mucosa to injury is attributable to a series of factors collectively known as "mucosal defense." Many components of mucosal defense are regulated by prostaglandins and nitric oxide (NO). Thus, inhibition of the production of these mediators predisposes the stomach to injury. Administration of these agents, as synthetic prostaglandins or NO donors, can restore mucosal defense and thereby prevent damage induced by several irritants. Repair of gastric ulcers is also influenced by NO and prostaglandins. Furthermore, a variety of growth factors appear to play critical roles in stimulating the formation of granulation tissue (the "foundation" for repair), the formation of new blood vessels, and the proliferation of epithelial cells. Better understanding of the factors that regulate ulcer healing should provide clues for the development of drugs that can produce better "quality" healing of ulcers.