Residual Inflammatory Potential in Patients with Treated Non-Definite and Definite Familial Hypercholesterolaemia: A Clinical Study

Background: Familial hypercholesterolemia (FH) is associated with accelerated atherosclerosis and an increased risk of cardiovascular disease. Aims: To evaluate circulating biomarkers of inflammation and atherosclerosis in patients with clinically suspected FH stratified according to the Dutch Lipid Clinic Network (DLCN) criteria. Methods: This cross-sectional study included 80 patients (mean age, 53.4 [13.2] years; 58% women) receiving maximally tolerated lipid-lowering therapy (statins ± ezetimibe). Serum concentrations of lipoprotein-associated phospholipase A2 (Lp-PLA2), tumor necrosis factor-α (TNF-α), apolipoprotein B (ApoB), oxidized low-density lipoprotein (oxLDL), and monocyte chemoattractant protein-1 (MCP-1) were measured. Participants were classified as definite FH (DLCN score > 8; n = 45) or non-definite FH (DLCN score ≤ 8; n = 35). Biomarker concentrations were analyzed according to the above subgroups and sex. Results: Patients with definite FH had significantly higher serum Lp-PLA2 concentrations (62.2 [33.8] vs. 46.5 [19.9] ng/mL; p = 0.03) and TNF-α concentrations (6.94 [4.53] vs. 4.51 [2.93] pg/mL; p = 0.02) compared to non-definite FH, whereas ApoB, oxLDL, and MCP-1 concentrations did not differ significantly between the subgroups. Women had significantly higher TNF-α concentrations compared to men (6.57 [4.74] vs. 4.60 [2.20] pg/mL; p = 0.04) with no differences among other cytokines. Conclusions: Patients with definite FH exhibited persistently higher circulating Lp-PLA2 and TNF-α concentrations despite maximally tolerated lipid-lowering therapy, suggesting ongoing activation of specific inflammatory pathways. These findings support further investigation of Lp-PLA2 and TNF-α as candidate biomarkers for cardiovascular risk assessment in FH.