Atherogenic markers in predicting cardiovascular risk and targeting residual cardiovascular risk

Evaluation of measured and calculated small dense low-density lipoprotein in capillary blood and association with the metabolic syndrome

BACKGROUND AND AIMS

Small-dense-low-density-lipoprotein cholesterol (sdLDL-C) is proatherogenic and not commonly measured. The aims were to evaluate capillary blood and its stability for sdLDL-C measurement and measure sdLDL-C in patients with metabolic syndrome (MS).

METHODS

182 patients were studied (49 with MS). sdLDL-C was measured by electrophoresis (LipoPrint®), direct measurement (Roche Diagnostics) and Sampson equation. Intima-media thickness (IMT) and presence of atheroma was evaluated. sdLDL-C was compared in paired venous and capillary blood according to CLSI-EP09c (n = 40). sdLDL-C stability was studied after 24 h at room temperature (RT).

RESULTS

sdLDL-C in capillary blood and venous blood showed agreement with the direct measurement (bias: 4.17 mg/dL, LOA 95 %:-5.66; 13.99) and estimation (bias:8.12 mg/dL, LOA 95 %:-8.59; 24.82). sdLDL-C is stable in capillary blood for 24 h at RT. The electrophoretic method yielded lower (p < 0.05) sdLDL-C than the equation or direct measurement. Patients with MS had (p < 0.05) higher sdLDL-C (%) than patients without MS. Patients with atheroma plaques had higher sdLDL-C (p < 0.05). Estimated sdLDL-C correlated with IMT (r = 0.259, p < 0.001).

CONCLUSIONS

Capillary blood is an alternative to venous blood for sdLDL-C measurement and is stable for 24 h after collection. Estimated and directly measured sdLDL-C associate with the MS being accessible tools for cardiovascular risk assessment.

Sialic acid as a potential biomarker for cardiovascular disease, diabetes and cancer

Cardiovascular disease (CVD), diabetes and cancer pose increasing global healthcare burdens. New biomarkers could enable earlier diagnosis of these diseases, leading to more effective treatment and lower associated healthcare burden. Elevated sialic acid concentration in plasma and serum has been positively correlated with the presence of CVDs, diabetes and the development of malignant tumors. This article reviews the use of total sialic acid (TSA), bound sialic acid (BSA) and free sialic acid (FSA) as potential biomarkers for these diseases and makes a comparison with existing markers. Elevated sialic acid has been shown to be indicative of the pathogenesis of CVD, diabetes and malignant tumors. While not a specific marker for one disease there is promise in utilizing sialic acid as a marker for monitoring disease progression and effectiveness of treatment programs.

Small dense low-density lipoprotein: Analytical review

BACKGROUND

The causal relationship between low-density lipoprotein (LDL) and atherosclerotic cardiovascular disease (CVD) has been firmly substantiated. LDL consists of a heterogeneous group of particles with different physicochemical and metabolic properties. Among them, small dense LDL (sdLDL) particles are considered an emerging CVD risk factor and a promising CVD risk biomarker. This paper reviews published analytical and calculation-based methods for sdLDL determination in plasma, present their principles, strengths, and weaknesses, and examine the challenges arising from method comparison.

METHODS

A literature survey was conducted using the PubMed database. Subject headings and keywords facilitated the search strategy. Titles and abstracts were initially assessed, and the full-text article of the pre-selected ones was reviewed.

RESULTS

A range of methods is currently available for the analysis of LDL subfractions and the measurement of sdLDL particle size, number, and cholesterol concentration. Ultracentrifugation (UC), vertical auto profile, gradient gel electrophoresis (GGE), nuclear magnetic resonance (NMR) spectroscopy, high-performance liquid chromatography, ion mobility analysis, and a homogeneous assay are the most prevalent. To date, there is no "gold standard". UC and GGE are the most established techniques, albeit significantly sophisticated. NMR and the homogeneous assay are options with potential clinical use as they yield results rapidly and can be high-throughput. None of the proposed equations for the calculated sdLDL determination has been sufficiently validated to serve as a clinical tool.

CONCLUSIONS

Many analytical procedures have been developed for the study of sdLDL particles. Their use remains largely restricted to research laboratories since their analytical and clinical performance, along with the clinical- and cost-effectiveness of sdLDL determination have not been fully established.