Biomarkers of cardiac disease

Chemotherapeutic-Induced Cardiovascular Dysfunction: Physiological Effects, Early Detection-The Role of Telomerase to Counteract Mitochondrial Defects and Oxidative Stress

Although chemotherapeutics can be highly effective at targeting malignancies, their ability to trigger cardiovascular morbidity is clinically significant. Chemotherapy can adversely affect cardiovascular physiology, resulting in the development of cardiomyopathy, heart failure and microvascular defects. Specifically, anthracyclines are known to cause an excessive buildup of free radical species and mitochondrial DNA damage (_mtDNA) that can lead to oxidative stress-induced cardiovascular apoptosis. Therefore, oncologists and cardiologists maintain a network of communication when dealing with patients during treatment in order to treat and prevent chemotherapy-induced cardiovascular damage; however, there is a need to discover more accurate biomarkers and therapeutics to combat and predict the onset of cardiovascular side effects. Telomerase, originally discovered to promote cellular proliferation, has recently emerged as a potential mechanism to counteract mitochondrial defects and restore healthy mitochondrial vascular phenotypes. This review details mechanisms currently used to assess cardiovascular damage, such as C-reactive protein (CRP) and troponin levels, while also unearthing recently researched biomarkers, including circulating _mtDNA, telomere length and telomerase activity. Further, we explore a potential role of telomerase in the mitigation of mitochondrial reactive oxygen species and maintenance of _mtDNA integrity. Telomerase activity presents a promising indicator for the early detection and treatment of chemotherapy-derived cardiac damage.

Cardiac biomarkers in diabetes mellitus: New dawn for risk stratification?

Type 2 diabetes mellitus (T2DM) remains a leading cause of cardiovascular (CV) events and diseases worldwide. The aim of the review is to summarize our knowledge regarding clinical implementation of the biomarker-based strategy of the CV risk assessment in T2DM patient population. There is large body of evidence regarding use of the cardiac biomarkers to risk stratification at higher CV risk individuals who belongs to general population and cohort with established CV disease. Although T2DM patients have higher incidence of macrovascular and microvascular CV complications than the general population, whether cardiac biomarkers would be effective to risk stratification of the T2DM is not fully understood. The role of natriuretic peptides, galectin-3, interleukins, growth differentiation factor-15, as well as biomarkers of endothelial dysfunction are widely discussed. In conclusion, future directions, which associate with discovering of novel biomarkers and their best combinations to provide additional predictive information beyond other traditional CV risk factors, are discussed.

Aortic stenosis: a general overview of clinical, pathophysiological and therapeutic aspects

Aortic stenosis is the most prevalent valve pathology and calcific aortic valve disease (CAVD) is its most frequent etiology in developed countries. There is extensive evidence that CAVD represents an active disease process similar to that of atherosclerosis with similar classical cardiovascular risk factors and pathological mechanisms. Given that in the vast majority of situations the only treatment available is valve replacement there is a need to develop pharmacological therapies that retard the disease progression. Lipid-lowering therapies have been the focus of research, however, so far with negative results. Future studies, including animal models, shall provide an opportunity to further evaluate the disease mechanisms of CAVD and to discover potential disease biomarkers and pharmacological interventions that can reduce the need for valve replacement.

Metabolic biomarkers for predicting cardiovascular disease

Cardiac and peripheral vascular biomarkers are increasingly becoming targets of both research and clinical practice. As of 2008, cardiovascular-related medical care accounts for greater than 20% of all the economic costs of illness in the United States. In the age of burgeoning financial pressures on the entire health care system, never has it been more important to try to understand who is at risk for cardiovascular disease in order to prevent new events. In this paper, we will discuss the cost of cardiovascular disease to society, clarify the definition of and need for biomarkers, offer an example of a current biomarker, namely high-sensitivity C-reactive protein, and finally examine the approval process for utilizing these in clinical practice.

Vascular proteomics

Cardiovascular diseases constitute the largest of death in developed countries, being atherosclerosis the major contributor. Atherosclerosis is a process of chronic inflammation, characterized by the accumulation of lipids, cells, and fibrous elements in medium and large arteries. There is a continuum in atherosclerotic cardiovascular pathology that extends from the initial endothelial damage to diseases such as angina, myocardial infarction, and stroke. The extent of inflammation, proteolysis, calcification, and neovascularization influences the development of advanced lesions (atheroma plaques) on the arteries. Plaque rupture and the ensuing thrombosis cause the acute complications of atherosclerosis, i.e., myocardial infarction and cerebral ischemia. Thus, identification of early biomarkers of plaque unstability and susceptibility to rupture is of capital importance in preventing acute events. In recent years proteomics has been successfully applied to study proteins involved in these pathological processes. Thus, proteomic studies have been carried out focusing on different elements such as vascular tissues (arteries), artery layers, cells looking at proteomes and secretomes, plasma/serum, exosomes, lipoproteins, and metabolites. This chapter will provide an overview of latest advances in proteomic studies of atherosclerosis and related vascular diseases.

Multiple reaction monitoring (MRM) of plasma proteins in cardiovascular proteomics

Different methodologies have been used through years to discover new potential biomarkers related with cardiovascular risk. The conventional proteomic strategy involves a discovery phase that requires the use of mass spectrometry (MS) and a validation phase, usually on an alternative platform such as immunoassays that can be further implemented in clinical practice. This approach is suitable for a single biomarker, but when large panels of biomarkers must be validated, the process becomes inefficient and costly. Therefore, it is essential to find an alternative methodology to perform the biomarker discovery, validation, and -quantification. The skills provided by quantitative MS turn it into an extremely attractive alternative to antibody-based technologies. Although it has been traditionally used for quantification of small molecules in clinical chemistry, MRM is now emerging as an alternative to traditional immunoassays for candidate protein biomarker validation.

Experimental SSM-CVB3 infection in macaques

OBJECTIVE

To evaluate the pathogenicity of SSM-CVB3 in a macaque model.

METHODS

The clinical symptoms of macaques were recorded; hematological, biochemical and histopathological evaluations were completed; viral titers and neutralization titers (NT-titers) in sera were tested; and the mRNA levels of SSM-CVB3, coxsackievirus and adenovirus receptor (CAR) and decay accelerating factor (DAF) were determined.

RESULTS

After SSM-CVB3 infection, the macaques showed a lack of activity, a poor appetite, a higher body temperature, and severe diarrhea. The macaques also developed hematuria and albuminuria at 4 to 10 days post-inoculation. Virus titers (5.1-6.5 LogTCID(50)/mL) were higher at 6 to 10 days post-inoculation, and NT-titers (6.5-7.3 Log2) reached plateaus at 8 to 14 days post-inoculation. The infected macaques developed serious anemia with decreased RBC and WBC, but the percentages of LYM were increased. The levels of CK, CK-MB, AST and ALT in the sera were 84-169 U/L, 87.6-271.1 U/L, 43-87 U/L and 43-82 U/L, respectively, and all of those were higher than normal. Histological analysis showed obvious cardiac, hepatic and renal damages in the infected macaques and the mRNA contents of SSM-CVB3, CAR and DAF in the heart, liver and kidneys of infected macaques were higher (P<0.05).

CONCLUSION

This was the first report on experimental SSM-CVB3 infections in macaques with serious hepatic and renal damage, except for myocarditis. The information obtained from this study suggests that the SSM-CVB3 strain and this macaque model could be used for studying CVB3-induced cardiac, hepatic or renal diseases.

The autoimmune origin of atherosclerosis

Atherosclerosis is a chronic inflammatory disease. Many studies and observations suggest that it could be caused by an immune reaction against autoantigens at the endothelial level, the most relevant of which are oxidized LDL and heat shock proteins (HSP) 60/65. Endothelial dysfunction plays a fundamental role. The first antigen is related to the increased leakage and oxidation of LDL; the second to cellular reaction to stress. Experimental and clinical observations confirm the pathogenetic role of these antigens. Both innate and adaptive immunity and impaired regulatory mechanisms of the autoimmune reaction are involved. Different triggering factors are examined: infectious agents, smoking, air pollution, diabetes and hypercholesterolemia. Analogies and differences between systemic atherosclerosis and transplant-related coronary atherosclerosis help to understand their respective nature. Immune mechanisms might be responsible for the passage from stable plaque to unstable and rupture-prone plaque. Finally, prospects of treatment and prevention are linked to the induction of tolerance to responsible antigens, activation of immune regulatory response and the use of immunomodulatory drugs.

Circulating human monocytes in the acute coronary syndrome express a characteristic proteomic profile

We examined the proteome of circulating monocytes of patients with acute coronary syndrome at different times in comparison to that of patients with stable coronary artery disease. On admission, the expression of 18 spot proteins was altered, 10 of which were totally absent. This pattern changed progressively, and at 6 months, there were no differences with the monocyte proteome of stable patients.

Quest for novel cardiovascular biomarkers by proteomic analysis

Atherosclerosis, and the resulting coronary heart disease and stroke, is the most common cause of death in developed countries. Atherosclerosis is an inflammatory process that results in the development of complex lesions or plaques that protrude into the arterial lumen. Plaque rupture and thrombosis result in the acute clinical complications of myocardial infarction (MI) and stroke. Although certain risk factors (dyslipidemias, diabetes, hypertension) and humoral markers of plaque vulnerability (C-reactive protein, interleukin-6, 10 and 18, CD40L) have been identified, a highly sensitive and specific biomarker or protein profile, which could provide information on the stability/vulnerability of atherosclerotic lesions, remains to be identified. In this review, we report several proteomic approaches which have been applied to circulating or resident cells, atherosclerotic plaques or plasma, in the search for new proteins that could be used as cardiovascular biomarkers. First, an example using a differential proteomic approach (2-DE and MS) comparing the secretome from control mammary arteries and atherosclerotic plaques is displayed. Among the different proteins identified, we showed that low levels of HSP-27 could be a potential marker of atherosclerosis. Second, we have revised several studies performed in cells involved in the pathogenesis of atherosclerosis (foam cells and smooth muscle cells). Another approach consists of performing proteomic analysis on circulating cells or plasma, which will provide a global view of the whole body response to atherosclerotic aggression. Circulating cells can bear information reflecting directly an inflammatory or pro-coagulant state related to the pathology. As an illustration, we report that circulating monocytes and plasma in patients with acute coronary syndromes has disclosed that mature Cathepsin D is increased both in the plasma and monocytes of these patients. Finally, the problems of applying proteomic approach directly to plasma will be discussed. The purpose of this review is to provide the reader with an overview of different proteomic approaches that can be used to identify new biomarkers in vascular diseases.