The Impact of a Single Apheretic Procedure on Endothelial Function Assessed by Peripheral Arterial Tonometry and Endothelial Progenitor Cells

Abstract

Introduction: Endothelial progenitor cells (EPC) are involved in vascular repair and proliferation, contributing to the long-term outcomes of apheretic treatment. Aim of this study was to investigate the relationships between endothelial function, assessed by levels of bone marrow-derived progenitor cells and endothelial response to hyperaemia, and clinical and biohumoral parameters in high vascular risk patients before, immediately after, 24-hours and 72 hours after a single lipid apheresis procedure. Material and Methods:We evaluated lipid profi le, endothelial function and endothelial progenitor cells before (T0), immediately after (T1), 24h after (T2) and 72h after (T3) a lipoprotein apheresis procedure, in 8 consecutive patients [Sex: 62.5% M; Age; 63.29(12), mean, (range) years] with a personal history of acute coronary syndrome, symptomatic peripheral arterial disease and elevated plasma levels of lipoprotein (a) [Lp(a)]. Patients were on regularly weekly or biweekly lipoprotein apheresis, and they were treated with the FDA-approved Heparin-induced Extracorporeal LDL Precipitation (H.E.L.P.) (Plasmat Futura, B.Braun, Melsungen, Germany) technique. PAT values were expressed as the natural logarithm (Ln-RHI, normal values≥0.4) of the reactive hyperaemia index (RHI), which is the parameter automatically calculated by the device. Results:We found a reduction in the natural logarithm of reactive hyperaemia index (Ln-RHI), assessed immediately after the procedure (0.57±0.21 vs 0.72± 0.29); difference between T2 and T0 was statistically signifi cant (0.43±0.24 vs 0.72±0.29; p=0.006). Reduction in Ln-RHI values was documented in all patients, two subjects showing a Ln-RHI<0.4 at T1, and four at T2. At T3, PAT values were increased signifi cantly (0.91±0.18) in comparison to T1 and T2, showing a median value higher than at T0. Cd34+/Kdr+ and Cd133+/Kdr+ showed a minimum increase in median values at T1, and a higher increase at T2, in comparison to baseline. Differences in Cd34+/133+/Kdr+ values at different times were not statistically signifi cant. A signifi cant reduction in circulating endothelial cells (CEC) count at T2 in comparison to T0 was found (12.00±8.85 vs 23.86±12.39; p=0.024). Discussion:At 24h and 72h after procedures, we found an improvement in endothelial function, expressed by an increase in PAT values and EPC levels, and by a reduction in CEC.