Abnormal adhesion of red blood cells to endothelium under flow conditions in diseases

Patients with Polythemia vera (PV) have a high incidence of thrombosis (25-75 %). Vascular complications are responsible of retinopathy, renal failure and coronary disease in diabetes mellitus (DM). Retinal Vascular Vein Occlusion (RVO) is a cause of blindness. To evaluate is red blood cell (RBC) abnormalities may be one vascular risk in these disease we studied RBC adhesion to endothelial cells in flow conditions.We found that RBC of patients with DM had the higher number of adhering RBC at 0.03 and up to 0.2Pa (7-2x10 RBC per mm). RBC from patients with PV and RVO have a significantly increased adhesion up to 0.2Pa. Antibodies directed against Lu/BCAM inhibited adhesion of RBC from PV patients. The Receptor for Advanced Glycation End Products (RAGE) was shown to be a receptor for RBC glycated band 3. In this study we observed that soluble RAGE which binds to AGE RBC reduced adhesion in flow conditions. RBC from patients with RVO were shown to exibit a higher level of phosphatidyl serine (PS). Using either anti PS receptor or Annexin V, which binds to PS, we significantly reduce RBC adhesion indicating that PS RBC and endothelial PS receptor are involved in RBC adhesion.