Proprotein convertase subtilisin/kexin type 9 in rheumatoid arthritis

Objective Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a serine protease that regulates cholesterol metabolism through low-density lipoprotein receptor degradation and that has been linked with cardiovascular risk. The purpose of the present study was to examine whether PCSK9 levels are related to both abnormalities in the lipid profile and the severe atherosclerosis that occur in rheumatoid arthritis (RA) patients. Methods Cross-sectional study that encompassed 520 individuals; 326 patients with RA and 194 age- and sex-matched controls. PCSK9 and lipoproteins serum concentrations, standard lipid profile and carotid intima-media thickness (cIMT) and carotid plaques were assessed in patients and controls. A multi variable analysis, adjusted for standard cardiovascular risk factors, was performed to evaluate the influence of PCSK9 on RA related dyslipidaemia and subclinical carotid atherosclerosis. Results After adjusting for classical cardiovascular risk factors, lipid profile and statins, RA patients showed lower PCSK9 serum concentrations than controls (beta coefficient - 45 95%CI (-53,-381 ng/ml, p=0.00). PCSK9 was associated with both cIMT and the presence of carotid plaques in RA patients. However, this association was lost after adjusting for classical cardiovascular risk factors. Conclusion PCSK9 is down-regulated in patients with RA.