Association Between <scp>HNP1</scp> ‐3 and Atherosclerotic Plaque Burden in Subclinical Atherosclerosis and the Mediating Effect of <scp>PCSK9</scp>

Subclinical atherosclerosis is a key predictor of cardiovascular events. While inflammation plays a crucial role in atherosclerosis, the involvement of Human Neutrophil Peptides 1-3 (HNP1-3) in its progression remains unclear. The study investigates the association of HNP1-3 and PCSK9 with coronary atherosclerotic burden and explores the potential mediatory role of PCSK9 in HNP1-3's effect on atherogenesis. Patients who underwent coronary computed tomographic angiography (CCTA) and had subclinical atherosclerosis (luminal stenosis < 50%) or normal coronary arteries were included in this cross-sectional study. HNP1-3 and PCSK9 levels were measured using ELISA, and coronary plaque burden was quantified using the modified Gensini score. Patients with subclinical atherosclerosis had significantly higher levels of HNP1-3 (p < 0.001), PCSK9 (p < 0.001), and lipoprotein(a) [Lp(a)] (p < 0.001) compared to controls. HNP1-3 was an independent predictor of subclinical atherosclerosis (p < 0.001), and its levels positively correlated with the modified Gensini score (p < 0.001). In multinomial logistic regression, higher levels of HNP1-3, PCSK9, and Lp(a) were independently associated with higher modified Gensini score tertiles. Mediation analysis revealed that PCSK9 mediated 48.7% of the effect of HNP1-3 on the modified Gensini score. After adjusting for hsCRP and cardiovascular risk factors, the direct effect of HNP1-3 became statistically insignificant, while the indirect effect via PCSK9 remained significant, suggesting that PCSK9 fully mediates the pro-atherogenic effects of HNP1-3. In conclusion, HNP1-3 is a novel independent predictor of subclinical atherosclerosis and coronary plaque burden, with its effects being mediated through PCSK9. These findings suggest that targeting PCSK9 could mitigate the inflammatory actions of HNP1-3, offering potential therapeutic insights for atherosclerosis prevention.