Fibrinogen and plasma clot properties are associated with apolipoprotein B and apolipoprotein B-containing lipoproteins in Africans

Background: Case-control, intervention and laboratory studies have demonstrated a link between apolipoprotein B-containing lipoproteins and clot structure and thrombosis. There is, however, limited evidence on population level.

Objectives: We determined the cross-sectional relationship between lipoprotein(a) (Lp(a)), low-density lipoprotein cholesterol (LDL-C), and apolipoprotein B (ApoB) with fibrinogen and plasma clot properties in 1 462 Black South Africans, a population with higher fibrinogen and Lp(a) levels compared with individuals of European descent.

Methods: Data were obtained from participants in the South African arm of the Prospective Urban and Rural Epidemiology study. Clot properties analysed included lag time, slope, maximum absorbance, and clot lysis time (turbidity). Lp(a) was measured in nM using particle-enhanced immunoturbidimetry. General linear models (GLM) were used to determine the associations between ApoB and ApoB-containing lipoproteins with fibrinogen and plasma clot properties. Stepwise regression was used to determine contributors to clot properties and Lp(a) variance.

Results: GLM and regression results combined, indicated fibrinogen concentration and rate of clot formation (slope) had the strongest association with Lp(a); clot density associated positively with both Lp(a) and LDL-C; time to clot formation associated negatively with ApoB; and CLT demonstrated strong positive associations with both ApoB and LDL-C, while its association with Lp(a) was fibrinogen concentration dependent.

Conclusion: These findings suggest that ApoB and the lipoproteins carrying it contribute to prothrombotic clot properties in Africans on epidemiological level and highlight potential novel prothrombotic roles for these (apo)lipoproteins to be considered for the development of targeted therapeutic approaches to address thrombotic conditions related to clot properties.