Human endothelial cell cultures from progenitor cells obtained by leukapheresis

Although improved prosthetic graft patency with endothelial cell (EC) seedi ng has been shown in animal models, the clinical application of this techni que requires a convenient source of ECs. We have evaluated EC cultures deri ved from the mononuclear cell (MNC) fraction obtained during large-volume l eukapheresis and compared this with cultures grown from peripheral blood ce lls obtained by phlebotomy. Leukapheresis was performed in healthy adult vo lunteers (n = 7) using software designed to increase the percentage of MNCs harvested. Blood (40-293 mL) was drawn from a peripheral vein in healthy a dult volunteers (n = 13), and the MNCs were obtained by differential centri fugation using a Lymphoprep gradient. Significantly more MNCs were obtained by leukapheresis than by phlebotomy. Each leukapheresis procedure yielded 12.5 to 23 mL, which contained 2.29 +/- 0.35 x 10(9) MNCs, compared with 2. 16 +/- 0.50 x 10(8) MNCs, for each phlebotomy (P < 0.001). EC colonies deve loped in significantly more cultures from leukapheresis-derived MNCs (6 of 7) than phlebotomy-derived MNCs (4 of 13; P = 0.008). Leukapheresis-derived cells developed EC morphology at 15.5 +/- 2 days compared with 21 +/- 3.4 days for cells obtained by phlebotomy (P = not significant). EC were identi fied by positive factor VIII and vascular endothelial growth factor recepto r immunostaining. Leukapheresis significantly increases the number of proge nitor cells available for differentiation into EC compared with phlebotomy and avoids the need for any surgical procedure to harvest a peripheral vein as a direct source of ECs.