Vascular and valvular calcification biomarkers

Vascular and valvular calcification constitutes a major health problem with serious clinical consequences. It is important for medical laboratorians to improve their knowledge on this topic and to know which biological markers may have a potential interest and might be useful for diagnosis and for management of ectopic calcifications. This review focuses on the pathophysiological mechanisms of vascular and valvular calcification, with emphasis on the mechanisms that are different for the two types of events, which underscore the need for differentiated healthcare, and explain different response to therapy. Available imaging and scoring tools used to assess both vascular and valvular calcification, together with the more studied and reliable biological markers emerging in this field (e.g., Fetuin A and matrix Gla protein), are discussed. Recently proposed functional assays, measuring the propensity of human serum to calcify, appear promising for vascular calcification assessment and are described. Further advancement through omic technologies and statistical tools is also reported. Clinical chemistry and laboratory medicine practitioners overlook this new era that will engage them in the near future, where a close cooperation of professionals with different competencies, including laboratorists, is required. This innovative approach may truly revolutionize practice of laboratory and of whole medicine attitude, making progression in knowledge of pathways relevant to health, as the complex calcification-related pathways, and adding value to patient care, through a precision medicine strategy.

Emerging Biomarkers of Oxidative Stress in Acute and Stable Coronary Artery Disease: Levels and Determinants

Background: Oxidative stress is crucial in the pathogenesis of atherosclerosis and acute myocardial infarction (AMI). Under the generic terms “oxidative stress” (OS), many biomarkers belonging to different pathways have been proposed. Aim: To compare the levels of recently proposed OS-related parameters in acute coronary syndromes (ACS) and stable coronary artery disease (CAD), to evaluate their effectiveness as additive risk or illness indicators of stable and acute ischemic events, and their response over time during the course of AMI. Methods: 76 ACS, 77 CAD patients, and 63 controls were enrolled in the study. Different OS-related biomarkers, including reactive oxygen metabolites (ROM), the total antioxidant capacity (OXY), nitrite/nitrate (final nitric oxide products, NO_x), and Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), were evaluated. Moreover, time response during AMI course (admission, and 6, 12, 18, 24, 36, and 48 hours after, T0-T6, respectively) and correlation with traditional cardiovascular (CV) risk factors (age, gender, hypertension, diabetes mellitus, dyslipidemia, smoking habit) were also assessed. Results: Over time, ROM progressively increased while OXY and NO_x decreased. Kinetics of LOX-1 during AMI shows that this biomarker boosts early during the acute event (T1 and T2) and then progressively decreases, being significantly lower from T0 to T6. Different OS-related biomarkers were differentially associated with CV risk factors and CAD or ACS presence. Conclusion: Differences in OS-related biomarkers (between groups, according to the response over time during AMI, and to the presence of CV risk factors) confirmed OS involvement in the transition from healthy status to stable CAD and ACS, although evidencing the heterogeneous nature of redox processes. In future, a multi-marker panel including different biomarkers and pathways of oxidative stress could be evaluated as an additive tool to be used in the CV prevention, diagnosis, patient stratification, and treatment.

Nontraditional Cardiovascular Biomarkers and Risk Factors: Rationale and Future Perspectives

The primary prevention of cardiovascular (CV) disease depends on the capacity to identify subjects at higher risk long before the occurrence of CV clinical manifestations. Traditional risk factors do not cover fully prediction of individual risk. Moreover, there is an area of gray for patients at intermediate CV risk, which offers wide margins of improvement. These observations highlight the need for new additive tools for a more accurate risk stratification. An increasing number of candidate biomarkers have been identified to predict CV risk and events, although they generally give only a moderate increase when added to currently available predictive scores. The approach utilizing a relative small number of biomarkers in multiple combinations, but only weakly related to each other or unrelated, thus belonging to independent-pathways, and so able to catch the multidimensional characteristic of atherosclerosis, appears promising. We discuss vitamin D and bone turnover biomarkers, hepatitis C virus, and psycho-emotional factors that may reflect alternative pathways over those generally considered for atherosclerosis (e.g., aspects directly related to inflammation and thrombosis). These new biomarkers could facilitate a more accurate assessment of CV risk stratification if incorporated in the current risk assessment algorithms.

Low concordance between HbA1c and OGTT to diagnose prediabetes and diabetes in overweight or obesity

BACKGROUND

Glycated haemoglobin (HbA1c) test, introduced for diagnosing prediabetes and diabetes by the American Diabetes Association for some years, is currently under extensive discussion for contradictory data on the concordance between this test and the oral glucose tolerance test (OGTT).

HYPOTHESIS

To assess concordance between HbA1c and OGTT to diagnose prediabetes and diabetes in subjects with overweight or obesity, focusing on possible gender-related differences.

METHODS

A total of 949 outpatients with overweight or obesity at risk for diabetes (mean age 50 ± 15 years; 660 F) were enrolled and underwent HbA1c test and OGTT.

RESULTS

In both genders, HbA1c test identified more patients with prediabetes than OGTT (42% vs 22% in males, 40% vs 18% in females, respectively): a slight concordance between HbA1c and OGTT (60% of total tests in both genders). In subjects diagnosed by OGTT, post-OGTT insulin levels and HOMA INDEX were significantly higher than those found in HbA1c(+) cases. Instead, those diagnosed with HbA1c were significantly older and showed higher uric acid than those with both tests (-).

CONCLUSIONS

HbA1c test and OGTT did not reach full concordance for the diagnosis of diabetes and prediabetes in both genders. The two tests likely reflect different physiopathological aspects of dysglycaemia, suggesting that the 'diagnostic thresholds' could be reconsidered in light of the discordance observed.