H.E.L.P apheresis exerts long term effects on the capacity of circulating proangiogenic cells

Severe forms of mono- and polygenetic hypercholesterolemia as well as elevated Lipoprotein (a) (LP(a)) with progressing cardiovascular (CV) disease are indication for lipoprotein apheresis (LA) in Germany. Many studies investigated pleiotropic effects of LA that might contribute to beneficial effects in advanced atherosclerosis. The present study aimed at investigating the potential role of Proangiogenic Cells (PAC) in patients with new onset or chronic LA using the heparin induced extracorporeal LDL-precipitation (H.E.L.P.) apheresis system.

Patients (n = 10) new to LA and HELP treatment were investigated immediately before, shortly after, 24 h later and 4 weeks following LA. Peripheral blood was used to count PAC in circulation via flow cytometry. In a second step, blood cells from patients were cultured in endothelial selective medium and further evaluated for adhesion in fibronectin coated chamber slides and migratory capacity (stromal cell-derived factor-1 (SDF-1) induced migration).

Cells expressing typical EPC markers were rarely detected in blood samples. No differences occurred over time in CD34⁺; CD34⁺ CD133⁺ CD45^-; CD34⁺/KDR⁺ and CXCR4⁺/CD14⁺ positive PAC. We found no differences in cell adhesion at the different time points, while significantly more cells migrated into the SDF-1 medium following four weeks of continuing apheresis therapy.

Using well established systems, this study was not able to demonstrate relevant acute effects of LA on PAC in patients new to LA. The increased migratory capacity of PAC might be an indicator of chronic beneficial pleiotropic effects in patients undergoing H.E.L.P. apheresis.