Prostaglandin E2 and prostaglandin F2 alpha biosynthesis in human gastric mucosa: effect of chronic alcohol misuse

Smoking and Alcohol Consumption and Risk of Incident Diverticulitis in Women

BACKGROUND & AIMS

Much of what is known about the effects of alcohol and tobacco use on diverticular disease derives from studies of asymptomatic diverticulosis or complicated diverticulitis. We examined smoking and alcohol consumption and risk of incident diverticulitis in a large cohort of women.

METHODS

We conducted a prospective study of 84,232 women in the Nurses' Health Study II (NHS II) who were 39-52 years old and without known diverticulitis at baseline in 2003. Smoking was ascertained every 2 years and alcohol use every 4 years. We used Cox proportional hazards regression to estimate multivariable-adjusted hazards ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

During 1,139,660 person-years of follow up, we identified 3018 incident cases of diverticulitis. After adjustment for other risk factors, current (HR, 1.20; 95% CI, 1.04-1.39) and past smoking (HR, 1.20; 95% CI, 1.11-1.30) were associated with increased risk of diverticulitis when compared with never smokers. Women who consumed ≥30 g/d of alcohol had a multivariate HR of 1.26 (95% CI, 1.05-1.50) when compared with women who did not drink. A joint analysis of smoking and alcohol found that individuals who ever smoked and consumed ≥15 g/d of alcohol were at highest risk of diverticulitis (multivariate HR, 1.60; 95% CI, 1.16-2.21), compared with participants who never smoked and reported no alcohol use.

CONCLUSIONS

In this large prospective study of women, smoking and alcohol consumption were associated with an increased risk of incident diverticulitis. These data highlight additional modifiable risk factors for diverticulitis that may aid in prevention.

A Prospective Study of Alcohol Consumption and Smoking and the Risk of Major Gastrointestinal Bleeding in Men

Background and Aims

Data regarding smoking and alcohol consumption and risk of gastrointestinal bleeding (GIB) are sparse and conflicting. We assessed the risk of major GIB associated with smoking and alcohol consumption in a large, prospective cohort.

Methods

We prospectively studied 48,000 men in the Health Professional follow-up Study (HPFS) who were aged 40–75 years at baseline in 1986. We identified men with major GIB requiring hospitalization and/or blood transfusion via biennial questionnaires and chart review.

Results

We documented 305 episodes of major GIB during 26 years of follow-up. Men who consumed >30 g/day of alcohol had a multivariable relative risk (RR) of 1.43 (95% confidence interval (CI), 0.88–2.35; P for trend 0.006) for major GIB when compared with nondrinkers. Alcohol consumption appeared to be primarily related to upper GIB (multivariable RR for >30 g/day vs. nondrinkers was 1.35; 95% CI, 0.66–2.77; P for trend 0.02). Men who consumed ≥ 5 drinks/week vs. < 1 drink/month of liquor had a multivariable RR of 1.72 (95% CI, 1.26–2.35, P for trend <0.001). Wine and beer were not significantly associated with major GIB. The risk of GIB associated with NSAIDs/aspirin use increased with greater alcohol consumption (multivariable RR 1.37; 95% CI, 0.85–2.19 for 1-14g/day of alcohol, RR 1.75; 95% CI, 1.07–2.88 for ≥ 15g/day compared to nondrinkers). Smoking was not significantly associated with GIB.

Conclusions

Alcohol consumption, but not smoking, was associated with an increased risk of major GIB. Associations were most notable for upper GIB associated with liquor intake. Alcohol appeared to potentiate the risk of NSAID-associated GIB.

Ethanol promotes chemically induced oral cancer in mice through activation of the 5-lipoxygenase pathway of arachidonic acid metabolism

Alcohol drinking is a known risk factor for oral cancer in humans. However, previous animal studies on the promoting effect of ethanol on oral carcinogenesis were inconclusive. It is necessary to develop an animal model with which the molecular mechanism of ethanol-related oral carcinogenesis may be elucidated to develop effective prevention strategies. In this study, mice were first treated with 4-nitroquinoline-1-oxide (4NQO, 100 μg/mL in drinking water) for 8 weeks and then given water or ethanol (8%) as the sole drink for another 16 weeks. During the experiment, 8% ethanol was well tolerated by mice. The incidence of squamous cell carcinoma (SCC) increased from 20% (8/41) to 43% (17/40; P < 0.05). Expression of 5-lipoxygenase (5-Lox) and cyclooxygenase 2 (Cox-2) was increased in dysplasia and SCC of 4NQO-treated tongues and further enhanced by ethanol. Using this mouse model, we further showed that fewer cancers were induced in Alox5(-/-) mice, as were cell proliferation, inflammation, and angiogenesis in the tongue, as compared with Alox5(+/+) mice. Interestingly, Cox-2 expression was induced by ethanol in knockout mice, whereas 5-Lox and leukotriene A4 hydrolase (LTA4H) expression and leukotriene B4 (LTB4) biosynthesis were dramatically reduced. Moreover, ethanol enhanced expression and nuclear localization of 5-Lox and stimulated LTB4 biosynthesis in human tongue SCC cells (SCC-15 and SCC-4) in vitro. In conclusion, this study clearly showed that ethanol promoted 4NQO-induced oral carcinogenesis, at least in part, through further activation of the 5-Lox pathway of arachidonic acid metabolism.

Relationship between alcohol consumption and active Helicobacter pylori infection

BACKGROUND

Helicobacter pylori (H. pylori) is a cause of chronic gastritis and maybe responsible for functional dyspepsia in a subset of patients. Many risk factors, such as alcohol consumption and smoking, may contribute to the colonization and infection of H. pylori in humans. However, studies on the relationship between H. pylori infection and drinking or smoking have produced conflicting results.

OBJECTIVE

The aim of this study was to examine whether consumption of alcohol or smoking is associated with active H. pylori infection in functional dyspepsia patients.

METHODS

H. pylori infection was confirmed by CLOtest and histology on at least two biopsies. Active chronic gastritis was diagnosed using the updated Sydney system. In addition to gender and age, information on drinking and smoking habits was collected using a standard questionnaire. Functional dyspepsia was diagnosed according to the Rome II diagnostic criteria.

RESULTS

H. pylori infection was positive in 27.3% of the 139 functional dyspepsia patients. Both age and gender were not significantly associated with H. pylori infection. A multiple logistic model found that alcohol consumption (OR = 9.05, 95% CI: 1.05-77.98) and pathology (active gastritis) (OR = 595.39, 95% CI: 81.43-4353.33) were associated with H. pylori infection. Active gastritis was associated with alcohol consumption (OR = 2.89, 95% CI: 1.03-8.02), smoking (OR = 2.72, 95% CI: 1.22-6.05) and age (OR = 1.03, 95% CI: 1.01-1.06).

CONCLUSIONS

In patients with functional dyspepsia, there is no significant association between active H. pylori infection and smoking. However, alcohol consumption appears to be associated with H. pylori infection.

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Nitric oxide and the hyperdynamic circulation in cirrhosis: is there a role for selective intestinal decontamination?

Abnormal vascular tone is responsible for many of the complications seen in cirrhosis making the identification of the pathophysiology of abnormal dilatation a major focus in hepatology research. The study of abnormal vascular tone is complicated by the multiple vascular beds involved (hepatic, splanchnic, peripheral, renal and pulmonary), the differences in the underlying cause of portal hypertension (hepatic versus pre-hepatic) and the slow evolution of the hyperdynamic state. The autonomic nervous system, circulating vasodilators and abnormalities in vascular smooth muscle cells (receptors, ion channels, signalling systems and contraction) have all been implicated. There is overwhelming evidence for an overproduction of NO (nitric oxide) contributing to the peripheral dilatation in both animal models of, and in humans with, cirrhosis and portal hypertension. This review focuses on the proposal that endotoxaemia, possibly from gut-derived bacterial translocation, causes induction of NOS (NO synthase) leading to increased vascular NO production, which is the primary stimulus for the development of vasodilatation in cirrhosis and its accompanying clinical manifestations. The current controversy lies not in whether NO production is elevated, but in which isoform of NOS is responsible. We review the evidence for endotoxaemia in cirrhosis and the factors contributing to gut-derived bacterial translocation, including intestinal motility and permeability, and finally discuss the possible role of selective intestinal decontamination in the management of circulatory abnormalities in cirrhosis.

Selective inhibition of COX-2 in humans is associated with less gastrointestinal injury: a comparison of nimesulide and naproxen

BACKGROUND

Selective inhibitors of cyclooxygenase (COX)-2 may provoke less gastric damage and platelet inhibition than conventional non-steroidal anti-inflammatory drugs.

AIMS

We compared the biochemical and gastrointestinal effects of nimesulide, a potent and selective COX-2 inhibitor, with naproxen which exhibits no selectivity.

SUBJECTS

Thirty six healthy volunteers were randomised to nimesulide 100 mg or naproxen 500 mg twice daily for two weeks in a double blind, crossover study with a washout between treatments.

METHODS

Gastrointestinal side effects were assessed by endoscopy, and by estimation of small intestinal absorption-permeability and inflammation. Comparisons were made between variables at the end of each treatment phase.

RESULTS

Nimesulide caused significantly less gastric injury using the modified Lanza score (p<0.001) as well as reduced duodenum injury (p=0.039). Nimesulide had lower visual analogue scores (VAS) for haemorrhage and erosive lesions in the stomach (p<0.001) and for mucosal injection in the duodenum (p=0.039). Naproxen increased excretion of calprotectin, a marker of intestinal inflammation (5.5 (1.2) to 12.1 (2.1) mg/l) while nimesulide had no effect (treatment difference p=0.03). Naproxen abolished platelet aggregation to arachidonic acid and suppressed serum thromboxane B(2) (TXB(2)) by 98%, indices of COX-1 activity. In contrast, nimesulide had no significant effect on platelet aggregation, although it reduced serum TXB(2) by 29%. Production of prostaglandin E(2) and prostacyclin by gastric biopsies, also COX-1 dependent, was inhibited by naproxen, but not by nimesulide. COX-2 activity, determined as endotoxin induced prostaglandin E(2) formation in plasma, was markedly suppressed by both treatments.

INTERPRETATION

Nimesulide has preferential selectivity for COX-2 over COX-1 in vivo at full therapeutic doses and induces less gastrointestinal damage than that seen with naproxen in the short term.

Alcohol's role in gastrointestinal tract disorders

When alcohol is consumed, the alcoholic beverages first pass through the various segments of the gastrointestinal (GI) tract. Accordingly, alcohol may interfere with the structure as well as the function of GI-tract segments. For example, alcohol can impair the function of the muscles separating the esophagus from the stomach, thereby favoring the occurrence of heartburn. Alcohol-induced damage to the mucosal lining of the esophagus also increases the risk of esophageal cancer. In the stomach, alcohol interferes with gastric acid secretion and with the activity of the muscles surrounding the stomach. Similarly, alcohol may impair the muscle movement in the small and large intestines, contributing to the diarrhea frequently observed in alcoholics. Moreover, alcohol inhibits the absorption of nutrients in the small intestine and increases the transport of toxins across the intestinal walls, effects that may contribute to the development of alcohol-related damage to the liver and other organs.