Omega-3 Fatty Acids,Mercury, and Selenium in Fish and the Risk of Cardiovascular Diseases

Fish consumption is associated with lower risk of cardiovascular disease. Some fish species also contain methylmercury, which may increase cardiovascular risk, as well as selenium, a trace element that could counter the effects of methylmercury or have beneficial effects itself. These potentially conflicting effects have created public confusion about the risks and benefits of fish consumption in adults. We examined the evidence for cardiovascular effects of fish consumption, particularly effects of marine omega-3 fatty acids, methylmercury, and selenium. Compelling evidence indicates that modest fish consumption substantially reduces cardiovascular risk, in particular cardiac mortality, related at least partly to benefits of omega-3 fatty acids. In contrast, observational studies and (for selenium) clinical trials demonstrate mixed and inconclusive results for cardiovascular effects of methylmercury and selenium. Net health benefits of overall fish consumption in adults are clear. Quantitative risk-benefit analyses of cardiovascular effects of consuming specific fish species, based on joint contents of fatty acids, methylmercury, and selenium, cannot currently be performed until the cardiovascular effects of methylmercury and selenium are established.     

Diabetes and Coronary Heart Disease as Risk Factors for Mortality in Older Adults

Background

Type 2 diabetes has been described as a coronary heart disease (CHD) “risk equivalent.” We tested whether cardiovascular and all-cause mortality rates were similar between participants with prevalent CHD vs diabetes in an older adult population in whom both glucose disorders and preexisting atherosclerosis are common.

Methods

The Cardiovascular Health Study is a longitudinal study of men and women (n = 5784) aged ≥65 years at baseline who were followed from baseline (1989/1992-1993) through 2005 for mortality. Diabetes was defined by fasting plasma glucose ≥7.0 mmol/L or use of diabetes control medications. Prevalent CHD was determined by confirmed history of myocardial infarction, angina, or coronary revascularization.

Results

Following multivariable adjustment for other cardiovascular disease risk factors and subclinical atherosclerosis, CHD mortality risk was similar between participants with CHD alone vs diabetes alone (hazard ratio [HR] 1.04, 95% confidence interval [CI], 0.83-1.30). The proportion of mortality attributable to prevalent diabetes (population-attributable risk percent = 8.4%) and prevalent CHD (6.7%) was similar in women, but the proportion of mortality attributable to CHD (16.5%) as compared with diabetes (6.4%) was markedly higher in men. Patterns were similar for cardiovascular disease mortality. By contrast, the adjusted relative hazard of total mortality was lower among participants with CHD alone (HR 0.85, 95% CI, 0.75-0.96) as compared with those who had diabetes alone.

Conclusions

Among older adults, diabetes alone confers a risk for cardiovascular mortality similar to that from established clinical CHD. The public health burden of both diabetes and CHD is substantial, particularly among women.     

The perfect storm: obesity, adipocyte dysfunction, and metabolic consequences

BACKGROUND: As the prevalence of adiposity soars in both developed and developing nations, appreciation of the close links between obesity and disease increases. The strong relationships between excess adipose tissue and poor health outcomes, including cardiovascular disease, diabetes, and cancer, mandate elucidation of the complex cellular, hormonal, and molecular pathophysiology whereby adiposity initiates and maintains adverse health effects. Content: In this report we review adipocyte metabolism and function in the context of energy imbalance and postprandial nutrient excess, including adipocyte hypertrophy and hyperplasia, adipocyte dysfunction, and other systemic consequences. We also discuss implications for laboratory evaluation and clinical care, including the role of lifestyle modifications. Chronic energy imbalance produces adipocyte hypertrophy and hyperplasia, endoplasmic reticulum stress, and mitochondrial dysfunction. These processes lead to increased intracellular and systemic release of adipokines, free fatty acids, and inflammatory mediators that cause adipocyte dysfunction and induce adverse effects in the liver, pancreatic beta-cells, and skeletal muscle as well as the heart and vascular beds. Several specialized laboratory tests can quantify these processes and predict clinical risk, but translation to the clinical setting is premature. Current and future pharmacologic interventions may target these pathways; modest changes in diet, physical activity, weight, and smoking are likely to have the greatest impact. Summary: Adipocyte endoplasmic reticulum and mitochondrial stress, and associated changes in circulating adipokines, free fatty acids, and inflammatory mediators, are central to adverse health effects of adiposity. Future investigation should focus on these pathways and on reversing the adverse lifestyle behaviors that are the fundamental causes of adiposity.     

Effect of glucagon-like peptide-1 (GLP-1) on glycemic control and left ventricular function in patients undergoing coronary artery bypass grafting

Increasing evidence suggests that tight glycemic control improves clinical outcomes after coronary artery bypass grafting (CABG). However, the risk for hypoglycemia with insulin often results in less aggressive glycemic control. Glucagon-like peptide-1 (GLP-1) is a naturally occurring peptide whose insulinotropic effects are predicated on the glucose concentration, minimizing the risk for hypoglycemia. This study was conducted to examine whether perioperative treatment with GLP-1 would affect glycemic control and improve hemodynamic recovery after CABG. Twenty patients with coronary heart disease and preserved left ventricular function who were scheduled to undergo CABG were randomized to receive standard therapy at the discretion of the surgeon or treatment with GLP-1 (1.5 pmol/kg/min) as a continuous infusion beginning 12 hours before CABG and continuing for 48 hours. Perioperative hemodynamics, the left ventricular ejection fraction, plasma glucose, and requirements for insulin drips and inotropic support were monitored. There were no differences between groups in the preoperative, postoperative, or 7-day left ventricular ejection fraction (GLP-1 61 +/- 4%, control 59 +/- 3%) or cardiac index at 18 hours (GLP-1 3.0 +/- 0.2 L/min/m(2), control 3.3 +/- 0.4 L/min/m(2)). However, the control group required greater use of inotropic and vasoactive infusions during the 48 hours after the operation to achieve the same hemodynamic result. There were also more frequent arrhythmias requiring antiarrhythmic agents in the control group. GLP-1 resulted in better glycemic control in the pre- and perioperative periods (GLP-1 95 +/- 3 mg/dl, control 140 +/- 10 mg/dl, p 相似文献   

Percutaneous renal intervention: comparison of 2-D and time-resolved 3-D (4-D) ultrasound for minimal calyceal dilation using an ultrasound phantom and fluoroscopic control

The rapid advances made by ultrasound in recent years have increasingly taken 3-D ultrasound (3DUS) and 4-D ultrasound (4DUS) from the research setting to the patient's bedside. There are still unexplored areas like renal percutaneous intervention, where 4DUS has yet to be proven an effective tool. Ultrasound-only guidance in renal percutaneous access is used in selected well-dilated pelvi-calyceal systems (PCS), and fluoroscopy is often utilized as an adjunct. Our aim was to compare 2-D and 4-D guidance for punctures, with fluoroscopy as control, using an in vitro ultrasound phantom. Agar and latex were the tissue-mimicking materials used for the construction of the phantom. The latex targets were designed to simulate multidirection-facing minimally dilated renal calyces. Two interventional fellows punctured the "calyces" using first 2DUS and then 4DUS guidance, making use of a different set of targets each time. The time to puncture, time to introduction of wire, quality of puncture (judged on fluoroscopy) and global rating of both modalities were documented. There was no significant difference between the times to puncture using 2DUS (1.8 min) and 4DUS (2 min). Nor was there a significant difference in the quality of puncture. 4DUS had a higher median difficulty rating. The multiplanar reformatted (MPR) longitudinal and transverse images were found to be the most useful for needle guidance. Cross hairs in all MPR images were not just useful in aligning the images on target but also as surrogate targets. The phantom was found to be robust, with only one instance of air introduction after 30 punctures. We have found that 4DUS is at least as good as 2DUS in terms of quality of punctures in vitro. The technology still has some way to go as frame rates, transducer size and resolution improve.