Chemokines and cardiovascular risk

Based on the importance of inflammation in atherogenesis, recent work has focused on whether plasma markers of inflammation can noninvasively diagnose and prognosticate atherosclerotic disorders. Although several studies support an important pathogenic role of chemokines in atherosclerosis, potentially representing attractive therapeutic targets in atherosclerotic disorders, this does not necessarily mean that chemokines are suitable parameters for risk prediction. In fact, the ability to reflect upstream inflammatory activity, stable levels in individuals, and high stability of the actual protein (eg, long half-life and negligible circadian variation) are additional important criteria for an ideal biomarker in cardiovascular disease. Although plasma/serum levels of certain chemokines (eg, interleukin- 8/CXCL8 and monocyte chemoattractant protein-1/CCL2) have shown to be predictive for future cardiac events in some studies, their role as clinical biomarkers is unclear, and their ability to predict subclinical atherosclerosis has been disappointing. Further prospective studies, including a larger number of patients, are needed to make any firm conclusion. Based on the participation of several chemokines in atherogenesis, it is possible that in the future, combined measurements of multiple chemokines could reveal as a "signature of disease" that can serve as a highly accurate method to assess for the presence of atherosclerotic disease.     

Obesity and cardiovascular risk

Obesity has assumed epidemic proportions and is expected to decrease the life expectancy of current and future generations by its cardiovascular complications and other associated chronic diseases. Recognizing the gravity of this trend, the American Heart Association recently identified obesity as an independent and important modifiable risk factor for cardiovascular disease. Obesity is known to cluster with other cardiovascular and metabolic risk factors constituting the cardiometabolic syndrome. The pathophysiogic link between obesity and cardiovascular disease is complex and involves multiple metabolic and inflammatory risk factors. In an attempt to better elucidate this major public health problem, this article reviews obesity as an epidemic, the structural and functional changes in the cardiovascular system as a result of obesity, and the pathophysiology of obesity-related cardiomyopathy. The sheer magnitude of the problem of obesity with its immense cardiovascular consequences warrants immediate intervention.     

Aldosterone and cardiovascular risk

Through its classic effects on sodium and potassium homeostasis, aldosterone, when produced in excess, is associated with the development of hypertension and hence with higher cardiovascular and renal risk. In recent years, experimental and epidemiologic data have suggested that aldosterone also may be linked to high cardiovascular risk independently of its effects on blood pressure. Thus, aldosterone has been associated with obesity and metabolic syndrome in selected populations, and these associations may further contribute to the higher cardiovascular risk of subjects with elevated aldosterone levels. Moreover, aldosterone has been reported to promote inflammation, oxidative stress, and fibrosis in a number of tissues. Clinical evidence indicates that patients with primary hyperaldosteronism have a higher risk of developing cardiovascular and renal complications than patients with essential hypertension who have the same level of blood pressure. Aldosterone receptor blockade has been shown to lower cardiovascular mortality after myocardial infarction and in patients with congestive heart failure. Some studies have also demonstrated that aldosterone blockade could have a favorable impact on the progression of renal disease. However, prospective interventional trials are needed to further evaluate the impact of blockade of aldosterone on cardiovascular risk.     

Hyperglycaemia and cardiovascular risk

Cardiovascular diseases represent, today, the principal cause of mortality in the general population, especially in subjects with type 2 diabetes mellitus. In these patients the risk of death from cardiovascular diseases is equal to that of non-diabetic subjects with a previous episode of myocardial infarction. Many factors concur to determine such high risk. Hyperglycaemia contributes to the increase in morbidity and cardiovascular mortality associated with diabetes mellitus. Hyperglycaemia acts as a multiplier of cardiovascular risk due to frequent association of multiple risk factors in diabetic patients. Therefore, effective treatment requires a more complete assessment of quantitative and qualitative aspects of glycemic control as well as all components of the diabetic syndrome or, more commonly, metabolic syndrome.     

Testosterone and cardiovascular risk

Cardiovascular (CV) disease is one of the most common causes of death in the western populations and, nowadays, its incidence is increasing even in the developing countries; although CV disease affects both sexes, it is more frequent in males in whom it shortens the average life expectancy. In this regard, this difference has been wrongly attributed for many years to the negative effects of testosterone (T); however, nowadays, a large amount of evidence suggests that this hormone may have protective effects on the CV system and that, indeed, the low levels of T could be associated with an increased CV risk and with an augmentation of morbidity and mortality in males. Such an aspect gains great relevance in light of the consideration that T decrease, besides occurring as a consequence of rare pathological conditions, can often take place with natural aging, causing a state of “male menopause”, also called late-onset hypogonadism. In this review, we aimed to summarize the present state of the art concerning the association between T deficit and CV disease by analyzing the protective role of T on CV system and the relationship of this hormonal lack with metabolic syndrome, CV morbidity and mortality, and with the CV complications, such as ischemic heart disease, heart failure and stroke, that frequently occur in T deficiency.     

Glucose and cardiovascular risk

The American Diabetes Association and the World Health Organisation have recently redefined the spectrum of abnormal glucose tolerance. The criteria for diabetes mellitus were sharpened and impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) were classified as intermediate stages between normal glucose homeostasis and diabetes, based on fasting and challenged glucose levels, respectively. Criteria were established for 'the metabolic syndrome', as a cluster of cardiovascular risk factors that frequently coincides with the abnormal glucose tolerance state. The extent to which the glucose level itself should be regarded as a cardiovascular risk factor is the subject of ongoing debate. Recent research suggests that cardiovascular risk is related to the plasma glucose level even in the normal range of glucose concentrations. The impact of glucose in relation to cardiovascular events is discussed in this review.     

Microalbuminuria and cardiovascular risk

Microalbuminuria is a marker for generalized vascular dysfunction. Its prevalence in United States and European general population surveys ranges from 6% to 10%. Increased risk for cardiovascular morbidity and mortality begins with albumin excretion rates that are well within normal limits. Although microalbuminuria interacts with the traditional cardiovascular risk factors, it has an independent relationship to renal and cardiovascular outcomes. For example, microalbuminuria doubles the risk for a cardiovascular event in patients with type 2 diabetes mellitus even after adjusting for the usual risk factors. Elevated rates of urinary albumin excretion predict target organ damage, notably renal disease, but are also related to left ventricular dysfunction, stroke, and myocardial infarction. Screening for microalbuminuria, which is recommended by several expert committees and associations, has become a readily accessible procedure. Screening can give clinicians prognostic information concerning cardiovascular risk and assist in guiding therapy. The goal of treatment is to prevent progression of, and even to reverse, microalbuminuria. Abundant evidence demonstrates that antihypertensive therapy is an important key to the control of urinary albumin excretion, and blockade of the renin-angiotensin system (with angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers) is the treatment of choice. These drugs have successfully halted or delayed the progression to nephropathy and have reversed elevated rates of albumin excretion to normal values, even when blood pressure reduction has been minimal.     

Rosiglitazone and cardiovascular risk

A meta-analysis of 42 clinical trials suggested that rosiglitazone, a widely used thiazolidinedione, was associated with a 43% greater risk of myocardial infarction (P = 0.03) and a 64% greater risk of cardiovascular death (P = 0.06). However, a number of criticisms have been raised that potentially undermine the conclusions of this analysis. In this article, we point out some of these limitations, summarize the currently available evidence concerning rosiglitazone and cardiovascular risk, share implications for drug safety evaluation, and offer practical recommendations to health care providers. We conclude that the data showing the increased risk for myocardial infarction and death from cardiovascular disease for diabetic patients taking rosiglitazone are inconclusive.     

Lipoproteins as coronary risk or non-risk indicators in elderly people

Lipid and apolipoprotein (apo) levels were investigated in 98 (68 female, 30 male) subjects older than 85 years and 86 (59 female, 27 male) subjects aged 65-75 years. The mean cholesterol level of the long-lived persons who were free from overt degenerative arterial disease was 5.2 mmol/l and ranged markedly below the mean level of the population. Comparing both age groups, the triglyceride level of the high-age subjects was at 0.3 mmol/l, significantly lower; HDL-cholesterol and apo A-I at 0.15 mmol/l or 0.3 g/l were higher. Cholesterol, LDL-cholesterol, and apo B only tended to be lower in the higher age. Subjects suffering from degenerative arterial disease (circulatory disturbance, hypertonia, diabetes mellitus), especially the long-lived group, had a more marked unfavorable lipoprotein profile. Subjects over 85 years (13%) had markedly less disturbance in lipoprotein metabolism of high atherogenic potency (hyper-beta-, hypo-alpha-lipoproteinemia) than did subjects 65-75 years old (23%). Hypertriglyceridemia is with 38% or rather 21% very frequent and seems to be of less atherogenic potency. Hyper-alpha-lipoproteinemia as anti-risk factor for coronary heart diseases was established more frequently in the long-lived group with 13% in comparison to 3.5% in those 65-75 years of age.     

Lipoproteins

The problem of plasma lipid transport between several organs is reviewed. The constitution of plasma lipoproteins is described as well as the importance of enzymes related to them. The problem of lipid transfer proteins is discussed. The origin of atherosclerosis is analyzed in relation to abnormalities of cholesterol metabolism, of its transport and of free radicals generation.     

Lipoprotein disorders and cardiovascular risk

Summary: Disorders of lipoproteins often lead to disease in humans. Most often the sequelae of long-term dyslipoproteinaemia lead to atherosclerotic vascular disease in all arterial beds. Plasma elevation of low-density lipoprotein cholesterol (LDL-C), very low-density lipoproteins (VLDL) and lipoprotein(a), and reduced levels of high-density lipoproteins (HDL-C) are risk factors for coronary artery disease. Severe elevations of plasma triglycerides may lead to acute pancreatitis. In Western societies and in emerging economies, lifestyle contributes to the expression of lipoprotein disorders. Many dyslipoproteinaemias have a genetic aetiology. This review will examine the contribution of genetic lipoprotein disorders in human disease. Emphasis will be placed on monogenic disorders that are associated with coronary artery disease and novel causes of disorders of high-density lipoproteins. The consideration of screening and treatment of affected individuals, especially children, must take into account the severity of the phenotype, the long-term risk of developing vascular disease and available evidence of clinical benefit in a group of diseases that are mostly asymptomatic until manifestations of organ ischaemia in the heart, limbs or brain. This revised version was published online in August 2006 with corrections to the Cover Date.     

Androgen excess and cardiovascular risk

Cardiovascular diseases represent the major cause of death in most of developed countries and ultimately kill as many men as women. Both genders are exposed to the same risk factors but their rates of cardiovascular morbidity and mortality are very different until old age. This represents a crucial point; in fact, only at age 75 and over cardiovascular rates of women approximate those of men. It has been suggested that differences in hormonal status and mainly in androgen levels may explain such gender disparity. Consistently with this hypothesis, it has been shown that women with polycystic ovary syndrome (PCOS) have elevated cardiovascular risk despite their young age. However, the possibility that androgens may increase cardiovascular risk remains controversial. Hyperandrogenism, as isolated androgen excess, has not been clearly recognised so far as a risk factor for cardiovascular diseases. In addition, the risk of premature cardiovascular diseases in PCOS is at present uncertain. Long-term studies examining the prevalence of cardiovascular diseases among women with PCOS did not demonstrate a clear increased risk for cardiovascular morbidity and mortality. Thus, it seems that androgens have a limited role in inducing cardiovascular risk; the altered risk factors found in women with PCOS are mainly dependent on the metabolic components of this syndrome as well as on insulin resistance and reduced adiponectin secretion.