Isolation and Transplantation of Autologous Circulating Endothelial Cells Into Denuded Vessels and Prosthetic Grafts

TLDR

Blood‑borne endothelial cells from adult bone marrow act as endothelial progenitor cells that can be mobilized by cytokines and recruited to sites of neovascularization, where they differentiate into mature endothelial cells. The study aims to develop a streamlined method for isolating and expanding endothelial progenitor cells from peripheral blood and assess their therapeutic potential for autologous repair of injured vessels and prosthetic grafts. The authors isolated EPCs by enriching CD34+ mononuclear cells, expanded them ex vivo, and efficiently transduced them with a retroviral LacZ vector to produce sufficient numbers for therapeutic use. In vitro, a subset of unfractionated mononuclear cells differentiated into endothelial cells, and when transplanted into balloon‑injured carotid arteries and bioprosthetic grafts in rabbits, they rapidly endothelialized the denuded segments and markedly reduced neointimal hyperplasia, suggesting a promising cell‑based therapy for vascular disease.

Abstract

Blood-borne endothelial cells originating from adult bone marrow were reported previously. These cells have the properties of an endothelial progenitor cell (EPC) and can be mobilized by cytokines and recruited to sites of neovascularization, where they differentiate into mature endothelial cells. Current protocols for isolation of EPCs from peripheral blood rely on enrichment and selection of CD34+ mononuclear cells.In this report, we describe a streamlined method for the isolation and expansion of EPCs from peripheral blood and evaluate their therapeutic potential for autologous cell-based therapy of injured blood vessels and prosthetic grafts. A subset of unfractionated mononuclear cells exhibited the potential to differentiate in vitro into endothelial cells under selective growth conditions. The cells were efficiently transduced ex vivo by a retroviral vector expressing the LacZ reporter gene and could be expanded to yield sufficient numbers for therapeutic applications. Transplantation of these cells into balloon-injured carotid arteries and into bioprosthetic grafts in rabbits led to rapid endothelialization of the denuded vessels and graft segments, resulting in significant reduction in neointima deposition.We conclude that transplantation of EPCs may play a crucial role in reestablishing endothelial integrity in injured vessels, thereby inhibiting neointimal hyperplasia. These findings may have implications for novel and practical cell-based therapies for vascular disease.