In-stent restenosis (ISR) is an unfavorable outcome that occurs in patients after coronary stenting. Using of drugs like statins as well as drug-eluting stents has only been partially effective in reducing the rate of ISR. Since low high-density lipoprotein cholesterol (HDL-C) concentration is a pivotal cardiovascular disease risk factor, this study aimed the evaluation of the compositional and functional alterations of HDL in individuals with ISR.

Material and methods:
This case-control study comprised 21 ISR, 26 non-ISR, 16 angiography-negative, and 18 healthy subjects. Serum HDL2 (d: 1.063-1.125 g/mL) and HDL3 (d: 1.125-1.210 g/mL) subfractions were extracted from each subject using sequential ultracentrifugation. The capacity of HDL to efflux cellular cholesterol from lipid-loaded macrophages as well as to uptake free cholesterol (FC) from triglyceride-rich lipoproteins (TGRL) during lipolysis were assessed.

No difference was found in the HDL2 and HDL3 content of free cholesterol and total protein among the groups. NISR group showed reduced triglyceride content in HDL2 and increased phospholipid content in HDL3 relative to healthy subjects. Strong positive correlations were found between the cholesterol efflux capacity (CEC) of HDL2 and its phospholipid content in the healthy (r=0.50), angiography-negative (r=0.55) and ISR (r=0.52) groups. The capacity of apolipoprotein B (apoB)-depleted serum to uptake free cholesterol was not different among the groups

Despite some compositional alterations, the capacity of HDL to efflux cholesterol from lipid-loaded macrophages as well as to uptake free cholesterol from TGRLs during lipolysis were not associated with ISR in this study