PCSK9 and its relationship with HMGB1, TLR4, and TNFα in non-statin and statin-treated coronary artery disease patients

Despite statin use in coronary artery disease (CAD), significant risk remains, potentially due to increased proprotein convertase subtilisin/kexin-type 9 (PCSK9) production, which raises LDL-C levels and induces inflammation. The exact relationship between PCSK9, inflammatory markers like TNF alpha, TLR4, CRP, and HMGB1, and monocyte subsets is poorly understood. This study aimed to explore these relationships in non-statin and statin-taking CAD patients. This case-control study included 91 controls and 91 stable CAD patients, divided into no-statin (NS, n = 25), low-dose statin (LDS, n = 25), and high-dose statin (HDS, n = 41) groups. Serum levels of LDL-C, CRP, PCSK9, TLR4, HMGB1, and TNF alpha were measured. Monocyte subsets were classified using flow cytometry into classical monocytes (CM), intermediate monocytes (IM), and non-classical monocytes (NCM). CAD patients showed elevated PCSK9, LDL-C, and inflammatory markers compared to controls. Statin groups (LDS, HDS) had lower LDL-C and inflammatory markers but higher PCSK9 than the NS group, with the HDS group showing the lowest LDL-C and inflammatory markers but the highest PCSK9. In the NS group, PCSK9 positively correlated with inflammatory markers (HMGB1, TNF alpha, TLR4, CRP) and monocyte subsets (IM%, NCM%). In the total statin group (LDS + HDS), PCSK9 negatively correlated with HMGB1, TLR4, and NCM%, for each, respectively, and positively with CM%. Multivariable linear regression showed significant associations between PCSK9 and HMGB1, NCM%, and IM% in the NS group, and HMGB1, NCM%, and TLR4 in the total statin group. In conclusion, we recommend combining PCSK9 inhibitors with statins in high-risk CAD patients. This may enhance statin efficacy, reduce LDL-C, and inhibit the TLR4/NF-& kcy;B inflammatory pathway, decreasing atherosclerotic inflammation.