Novel serologic markers of cardiovascular risk

Coronary atherosclerosis, low-density lipoproteins and markers of thrombosis, inflammation and endothelial dysfunction

Available information regarding the relation among atherosclerosis, low-density lipoproteins, markers of thrombosis, inflammation and endothelial dysfunction has accumulated, but is still very limited, making only minimal contributions to clinical decision-making. Many more clinical trials are needed, but unless there is a relationship between atherosclerosis prevention, specific markers and a pharmaceutical product, financial support for such trials will be difficult to obtain. The anti-inflammatory effect of statins is well established. Angiotensin-converting enzyme inhibitors are generally not thought of as having anti-inflammatory effects, but the European Trial on Reduction of Cardiac Events with Perindopril in Stable Coronary Artery Disease (EUROPA) study observed extensive RR reduction with perindopril. It was explained not simply by control of hypertension, but by reduced activity of multiple factors, supported by specific substudies. The 'cardiovascular continuum' is an excellent unifying term to explain atherosclerosis mechanisms, relate mechanisms to clinical understanding, and assist the clinician in selecting the appropriate prevention and control therapies. This so-called continuum actually describes a relationship among different biochemical, enzymatic and hormonal factors that affect the cardiovascular system. It can be seen in the downregulation of the angiotensin II receptor type 1 by statins, which contributes to hypertension control while lowering low-density lipoproteins. Peroxisome proliferator activator receptor-gamma also demonstrates the cardiovascular continuum with activation of the receptor by glitazones. The glitazones increase insulin sensitivity for diabetes control. Activation of the peroxisome proliferator activator receptor-gamma inhibits inflammation, which is possibly related to atherosclerosis, normalization of endothelial function, suppression of metalloproteinases and a decrease in smooth muscle cell migration. All of these effects may decrease atherosclerosis production while improving control of diabetes mellitus, a key disease in the cardiovascular continuum for development of atherosclerosis. Consideration of such interrelationships is just scratching the surface. Nevertheless, it can be seen that the complicated process of atherosclerosis development has a multifaceted explanation that has been minimally defined, but holds the key to prevention and control of this major medical problem faced in modern society.

Association of SF-36 with coronary artery disease risk factors and mortality: a PreCIS study

This study examined the relationships among health-related quality of life and risk factors of coronary artery disease (CAD) and all-cause mortality in high-risk cardiac patients seen in a cardiology prevention clinic. At baseline, 1785 patients (age, 53.4+/-13.4 years; 58.8% men) had a medical history, physical examination, and laboratory tests. They completed the Medical Outcomes Study Short Form-36-Item Health Survey (SF-36). Analyses were conducted on associations of 2 SF-36 domain scores (overall physical health [OPH] and overall mental health [OMH]) with CAD biomarkers and all-cause mortality. Lower OPH scores were associated with CAD risk factors including smoking; history of hypertension, diabetes, and peripheral artery disease; the metabolic syndrome; and other novel CAD biomarkers. Lower OMH scores showed similar but weaker associations with CAD risk factors. OPH significantly predicted 5-year mortality in multivariable survival analysis. SF-36, especially OPH, was associated with many risk factors of CAD and significantly predicted mortality.

Cardiovascular risk markers in obstructive sleep apnoea syndrome and correlation with obesity

BACKGROUND

High C-reactive protein (CRP) and homocysteine levels are risk factors for cardiovascular disease. Some, but not all, previous studies have reported increased levels of CRP and homocysteine in patients with obstructive sleep apnoea syndrome (OSAS). A study was undertaken to investigate the levels of these factors in carefully selected patients with OSAS and matched normal controls.

METHODS

CRP and homocysteine levels were measured in 110 subjects following polysomnography (PSG). Non-OSAS patients (group 1) were compared with two patient groups (mild/moderate OSAS (group 2) and severe OSAS (group 3)) group-matched for body mass index (BMI), and a fourth group of patients with severe OSAS who were more obese (group 4). All were free of other disease and similar in age, smoking habits and cholesterol levels. 50 suitable patients were commenced on continuous positive airway pressure (CPAP) treatment after PSG and 49 were reassessed 6 weeks later.

RESULTS

CRP levels were similar in groups 1, 2 and 3 (median (interquartile range (IQR)) 1.11 (0.76-2.11) mg/l vs 1.82 (1.20-3.71) mg/l vs 2.20 (1.16-3.59) mg/l; p=0.727, Kruskal-Wallis test), but were significantly higher in group 4 than in the other groups (5.36 (2.42-9.17) mg/l, p<0.05 by individual group comparisons). In multivariate analysis of all subjects, BMI was an independent predictor for CRP levels (beta=0.221; p=0.006) but apnoea-hypopnoea index and other measures of OSAS were not. There was no difference in homocysteine levels between all four groups (p=0.1). CPAP did not alter CRP (2.29 (1.32-4.10) vs 2.84 (1.13-5.40) mg/l; p=0.145) or homocysteine levels (8.49 (3.66) vs 9.90 (4.72) micromol/l; p=0.381).

CONCLUSION

CRP and homocysteine levels are not associated with OSAS severity in men but CRP is independently associated with obesity.

Translating genomic biomarkers into clinically useful diagnostics

The landmark sequencing of the human genome has ushered in a new field of large-scale research. Advances in understanding the molecular basis of disease have opened up new opportunities to develop genomics-based tools to diagnose, predict disease onset or recurrence, tailor treatment options, and assess treatment response. Although still in the early stages of research and development, genomic biomarker research has the capability of providing a comprehensive insight into pathophysiological processes as well as more precise predictors of outcome not previously attainable with traditional biomarkers. Before genomic biomarkers are incorporated into clinical practice, several issues will need to be addressed in order to generate the necessary levels of evidence to demonstrate analytical and clinical validity and utility. In addition, efforts will be needed to educate health professionals and the public about genomics-based tools, revise regulatory oversight mechanisms, and ensure privacy safeguards of the information generated from these new tests.