Beneficial effect of moderate alcohol consumption on vascular disease: myth or reality?

The Effects of Ethanol on the Heart: Alcoholic Cardiomyopathy

Alcoholic-dilated Cardiomyopathy (ACM) is the most prevalent form of ethanol-induced heart damage. Ethanol induces ACM in a dose-dependent manner, independently of nutrition, vitamin, or electrolyte disturbances. It has synergistic effects with other heart risk factors. ACM produces a progressive reduction in myocardial contractility and heart chamber dilatation, leading to heart failure episodes and arrhythmias. Pathologically, ethanol induces myocytolysis, apoptosis, and necrosis of myocytes, with repair mechanisms causing hypertrophy and interstitial fibrosis. Myocyte ethanol targets include changes in membrane composition, receptors, ion channels, intracellular [Ca2+] transients, and structural proteins, and disrupt sarcomere contractility. Cardiac remodeling tries to compensate for this damage, establishing a balance between aggression and defense mechanisms. The final process of ACM is the result of dosage and individual predisposition. The ACM prognosis depends on the degree of persistent ethanol intake. Abstinence is the preferred goal, although controlled drinking may still improve cardiac function. New strategies are addressed to decrease myocyte hypertrophy and interstitial fibrosis and try to improve myocyte regeneration, minimizing ethanol-related cardiac damage. Growth factors and cardiomyokines are relevant molecules that may modify this process. Cardiac transplantation is the final measure in end-stage ACM but is limited to those subjects able to achieve abstinence.

Platelets as Predictors of Vascular Risk: Is There a Practical Index of Platelet Activity?

Activated platelets play a role in the pathogenesis of coronary heart disease (CHD). Following activation, platelets change shape, aggregate, and release several bioactive substances. The aim of this review is to identify if there is a simple and cost-effective method that indicates platelet activation and predicts the risk of CHD and vascular events. The rationale for identifying high-risk patients is to reduce their risk of vascular events by administering appropriate and effective antiplatelet treatment, like aspirin, clopidogrel, or combination regimens. Many laboratory tests estimating platelet activity have been described. Some are relatively simple, such as spontaneous or agonist-induced platelet aggregation. Other tests include measuring the mean platelet volume (MPV) or plasma soluble P-selectin levels. Some more complex tests include flow cytometry to determine platelet GP Ilb/Illa receptors, platelet surface P-selectin, plateletmonocyte aggregates, and microparticles. Only few prospective studies assessed the predictive value of platelet activation in healthy individuals. Although the MPV seems an 'easy method, there are insufficient data supporting its ability to predict the risk of a vascular event in healthy adults. Platelet aggregation, in whole blood or in platelet-rich plasma was not consistently predictive of vascular risk. Soluble P-selectin measurement is a promising method but it needs further evaluation. Flow cytometry methods are costly, time-consuming, and need specialized equipment. Thus, they are unlikely to be useful in estimating the risk in large numbers of patients. There is as yet no ideal test for the detection of platelet activation. Each currently available test has merits and disadvantages. Simple methods such as the MPV and the determination of platelet release products need further evaluation.

Cardiovascular Risk Factors of Taxi Drivers

In the United States (U.S.), cardiovascular disease (CVD) is a major leading cause of death. Despite the high mortality rate related to CVD, little is known about CVD risk factors among urban taxi drivers in the U.S. A cross-sectional design was used to identify the predictors of high cardiovascular risk factors among taxi drivers. Convenience sampling method was used to recruit 130 taxi drivers. A structured questionnaire was used to obtain the data. The sample was male (94 %), age mean (45 ± 10.75) years, married (54 %), born outside of the USA (55 %), had some college or below (61.5 %), night drivers (50.8 %), and driving on average 9.7 years and 41 h/week. About 79 % of them were eligible for CVD prevention, and 35.4 % had high CVD risk factors (4-9 risk factors). A CVD high-risk profile had a significant relationship with the subjects who were ≥55 years old; had hypertension, diabetes, or hyperlipidemia; were drinking alcohol ≥2 times/week; and had insufficient physical activity. Subjects who worked as a taxi driver for more than 10 years (OR 4.37; 95 % CI 1.82, 10.50) and had mental exertion from cab driving >5 out of 10 (OR 2.63; 95 % CI 1.05, 6.57) were more likely to have a CVD high-risk profile. As a conclusion, system-level or worksite interventions include offering healthy food at taxi dispatching locations, creating a work culture of frequent walking breaks, and interventions focusing on smoking, physical activity, and weight management. Improving health insurance coverage for this group of workers is recommended.

Is alcohol drinking associated with renal impairment in the general population of South Korea?

BACKGROUND/AIMS

We examined relationships between the average amount of daily alcohol intake, drinking patterns, and renal dysfunction among South Korean adultsaged ≥ 20 years.

METHODS

The analysis used data from the Korean National Health and Nutrition Examination Survey (KNHANES), a cross-sectional survey of Korean civilians, conducted from January to December 2011. In this study, a sample of 5,251 participants was analysed.

RESULTS

Compared with abstinence, the odds ratio for a decrease in estimated glomerular filtration rate (eGFR) was 0.14 (95% CI: 0.01-0.91) among heavy drinkers, and 0.42 (95% CI: 0.17-0.98) among binge drinkers and the association between the amount of mean daily alcohol intake, binge-drinking status and a likelihood of reduced eGFR value showed significant trends (p = 0.041 and p = 0.038, respectively), after adjusting for age, smoking status, amount of physical activity, morbid hypertension, diabetes, dyslipidaemia, anaemia and body mass index. There was no significant association between alcohol consumption and the urine albumin to creatinine ratio in men, or between alcohol consumption and renal dysfunction in women.

CONCLUSIONS

Alcohol consumption was inversely associated with a reduction in eGFR in Korean men. However, these findings should be interpreted cautiously, given the other harmful effects related to alcohol consumption, especially heavy and binge drinking.

Lipoprotein a: where are we now?

PURPOSE OF REVIEW

To provide an update of the literature describing the link between lipoprotein a and vascular disease.

RECENT FINDINGS

There is evidence that elevated plasma lipoprotein a levels are associated with coronary heart disease, stroke and other manifestations of atherosclerosis. Several mechanisms may be implicated, including proinflammatory actions and impaired fibrinolysis.

SUMMARY

Lipoprotein a potentially represents a useful tool for risk stratification in the primary and secondary prevention setting. However, there are still unresolved methodological issues regarding the measurement of lipoprotein a levels. Targeting lipoprotein a in order to reduce vascular risk is hampered by the lack of well tolerated and effective pharmacological interventions. Moreover, it has not yet been established whether such a reduction will result in fewer vascular events. The risk attributed to lipoprotein a may be reduced by aggressively tackling other vascular risk factors, such as low-density lipoprotein cholesterol.

Prevention and treatment of the metabolic syndrome

The prevalence of the metabolic syndrome is increasing owing to lifestyle changes leading to obesity. This syndrome is a complex association of several interrelated abnormalities that increase the risk for cardiovascular disease and progression to diabetes mellitus (DM). Insulin resistance is the key factor for the clustering of risk factors characterizing the metabolic syndrome. The National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III defined the criteria for the diagnosis of the metabolic syndrome and established the basic principles for its management. According to these guidelines, treatment involves the improvement of the underlying insulin resistance through lifestyle modification (eg, weight reduction and increased physical activity) and possibly by drugs. The coexistent risk factors (mainly dyslipidemia and hypertension) should also be addressed. Since the main goal of lipid-lowering treatment is to achieve the NCEP low-density lipoprotein cholesterol (LDL-C) target, statins are a good option. However, fibrates (as monotherapy or in combination with statins) are useful for the treatment of the metabolic syndrome that is commonly associated with hypertriglyceridemia and decreased high-density lipoprotein cholesterol (HDL-C) levels. The blood pressure target is < 140/90 mm Hg. The effect on carbohydrate homeostasis should possibly be taken into account in selecting an antihypertensive drug. Patients with the metabolic syndrome commonly have other less well-defined metabolic abnormalities (eg, hyperuricemia and raised C-reactive protein levels) that may also be associated with an increased cardiovascular risk. It seems appropriate to manage these abnormalities. Drugs that beneficially affect carbohydrate metabolism and delay or even prevent the onset of DM (eg, thiazolidinediones or acarbose) could be useful in patients with the metabolic syndrome. Furthermore, among the more speculative benefits of treatment are improved liver function in nonalcoholic fatty liver disease and a reduction in the risk of acute gout.

Alcohol consumption and risk of stroke: a meta-analysis

CONTEXT

Observational studies suggest that heavy alcohol consumption may increase the risk of stroke while moderate consumption may decrease the risk.

OBJECTIVE

To examine the association between alcohol consumption and relative risk of stroke.

DATA SOURCES

Studies published in English-language journals were retrieved by searching MEDLINE (1966-April 2002) using Medical Subject Headings alcohol drinking, ethanol, cerebrovascular accident, cerebrovascular disorders, and intracranial embolism and thrombosis and the key word stroke; Dissertation Abstracts Online using the keywords stroke and alcohol; and bibliographies of retrieved articles.

STUDY SELECTION

From 122 relevant retrieved reports, 35 observational studies (cohort or case control) in which total stroke, ischemic stroke, or hemorrhagic (intracerebral or total) stroke was an end point; the relative risk or relative odds and their variance (or data to calculate them) of stroke associated with alcohol consumption were reported; alcohol consumption was quantified; and abstainers served as the reference group.

DATA EXTRACTION

Information on study design, participant characteristics, level of alcohol consumption, stroke outcome, control for potential confounding factors, and risk estimates was abstracted independently by 3 investigators using a standardized protocol.

DATA SYNTHESIS

A random-effects model and meta-regression analysis were used to pool data from individual studies. Compared with abstainers, consumption of more than 60 g of alcohol per day was associated with an increased relative risk of total stroke, 1.64 (95% confidence interval [CI], 1.39-1.93); ischemic stroke, 1.69 (95% CI, 1.34-2.15); and hemorrhagic stroke, 2.18 (95% CI, 1.48-3.20), while consumption of less than 12 g/d was associated with a reduced relative risk of total stroke, 0.83 (95%, CI, 0.75-0.91) and ischemic stroke, 0.80 (95% CI, 0.67-0.96), and consumption of 12 to 24 g/d was associated with a reduced relative risk of ischemic stroke, 0.72 (95%, CI, 0.57-0.91). The meta-regression analysis revealed a significant nonlinear relationship between alcohol consumption and total and ischemic stroke and a linear relationship between alcohol consumption and hemorrhagic stroke.

CONCLUSIONS

These results indicate that heavy alcohol consumption increases the relative risk of stroke while light or moderate alcohol consumption may be protective against total and ischemic stroke.

The role of platelets in peripheral arterial disease: therapeutic implications

Peripheral arterial disease (PAD) is associated with platelet hyperaggregability as well as an increase in morbidity and mortality from myocardial infarction and stroke. Enhanced platelet activation in PAD may substantially contribute to these adverse outcomes. A relative resistance to aspirin therapy has been reported in patients with PAD. Therefore, clopidogrel may be superior to aspirin in treatment of PAD. Furthermore, the aspirin + clopidogrel combination could be more effective than monotherapy but its risk-benefit ratio has yet to be evaluated. Clopidogrel is preferable to ticlopidine because of its safer profile and the convenience of once-daily administration. The glycoprotein (Gp) IIb/IIIa inhibitors may also find a place as short-term therapy after peripheral angioplasty. There is a need to consider the use of clopidogrel in patients who cannot tolerate aspirin. Patients who have an event while taking aspirin also present a problem. One possibility here is to substitute aspirin with clopidogrel or to add clopidogrel to the aspirin. Although these options are currently not evidence based in patients with PAD, there is emerging evidence showing that they are realistic choices.

Differential STAT5 activation and phenotypic marker expression by immune cells following low levels of ethanol consumption in mice

Ethanol has been recognized as an immunosuppressive agent for many years. Effects of high levels of ethanol consumption on immune functions have been extensively studied, but little is known about the effects of low levels (scuh as 5% ethanol) of ethanol consumption. Herein we report that exposure of mice to 5% ethanol for 4-8 weeks decreases IL-2-augmented splenic NK cell activity, decreases the numbers of NK cells in spleen and liver, decreases the number of granulocytes (Gr-l+) in bone marrow and spleen, and decreases the percentages of B cells in liver. In contrast, the percentages of CD4+CD8+ thymocytes, CD4+CD8- splenocytes, CD4+CD8- liver nonparenchymal cells, CD3+ splenocytes, and CD3+ bone marrow cells were increased. Furthermore, exposure to 5% ethanol increases STAT5 activation in T cells and liver cells while decreases STAT5 activation in NK cells. Taken together, these findings suggest that low levels of ethanol consumption can differentially modulate immune cells in thymus, spleen, bone marrow and liver, which may be due to differential regulation of STAT5 activation by ethanol.

Time to look beyond just lowering the serum concentration of low density lipoprotein--high density lipoprotein levels are also important

There is convincing epidemiological evidence indicating that the serum levels of high density lipoprotein (HDL) cholesterol are inversely related to the risk of vascular events. Similarly, intervention trials, involving healthy populations and patients with coronary heart disease (CHD), have shown that raising the serum levels of HDL is associated with a significant decrease in the risk of vascular events. It follows that serum HDL levels must be considered when assessing risk and setting therapeutic goals. Some of the currently available national treatment guidelines reflect this view. The present review considers the place of serum HDL measurement in the prevention of vascular events.