Impaired Antiatherogenic Functions of High-density Lipoprotein in Patients with Ankylosing Spondylitis

Objective. Ankylosing spondylitis (AS) is a chronic inflammatory disease associated with increased risk of cardiovascular disease (CVD). High-density lipoprotein (HDL) exerts a series of antiatherogenic properties and protects from CVD. We evaluated whether HDL antiatherogenic properties are impaired in patients with AS. Methods. HDL (apoB-depleted serum) was isolated from 35 patients with AS and 35 age- and sex-matched controls. We measured the antioxidant capacity of HDL, the ability of HDL to induce cholesterol efflux, the activity of HDL-associated enzymes paraoxonase-1 (PON1) and myeloperoxidase (MPO), as well as the ability of HDL to induce Akt kinase activation. Results. HDL from patients with AS had decreased antioxidant capacity and decreased ability to promote cholesterol efflux from macrophages compared to controls. HDL-associated PON1 activity was lower and HDL-associated MPO activity higher in patients with AS compared to controls. Higher MPO activity correlated positively with lower antioxidant capacity of HDL in patients with AS. In addition, HDL from patients with AS had impaired endothelial Akt kinase activating properties that were inversely correlated with the MPO/PON1 ratio and positively correlated with the cholesterol efflux capacity of HDL. Conclusion. HDL from patients with AS displays impaired antiatherogenic properties. Attenuation of HDL properties may constitute a link between AS and CVD.