Effect of low-density lipoprotein apheresis on inflammatory and noninflammatory high-density lipoprotein cholesterol

Low-density lipoprotein (LDL) apheresis, a treatment for familial hypercholesterolemia, significantly decreases LDL cholesterol and inflammatory markers such as C-reactive protein, CD40 ligand, and tissue factor. LDL apheresis also decreases high-density lipoprotein (HDL) cholesterol, which might be considered therapeutically counterproductive because HDL is known to be anti-inflammatory. However, recent studies have shown that HDL also possesses proinflammatory properties, as seen in its ability to alter LDL-induced monocyte chemotactic activity. We examined the acute effects of LDL apheresis on inflammatory HDL activity in 13 patients with familial hypercholesterolemia and cardiovascular disease who had been receiving bi-weekly LDL apheresis treatments. Immediately before and immediately after treatment, each patient's plasma was collected for analysis of inflammatory HDL and full lipid profile. LDL apheresis reduced LDL by 52% (from 208 +/- 89 to 99 +/- 48 mg/dl, p <0.002), and HDL decreased by 16% (49 +/- 15 to 41 +/- 13 mg/dl, p <0.003). At the same time, inflammatory HDL activity (in migrated monocytes per high-power field) decreased from 22 +/- 4 to 14 +/- 2, a 37% acute reduction (p <0.003). Moreover, inflammatory HDL before HDL apheresis was highly correlated with its acute reduction (r(s) = 0.85, p <0.001). In conclusion, our findings indicate that, in addition to decreasing LDL, LDL apheresis also decreases inflammatory HDL. The clinical significance of reducing inflammatory HDL is currently unknown, and further research is needed to examine its potential benefit for cardiovascular disease.