Endothelial Progenitor Cell Vascular Endothelial Growth Factor Gene Transfer for Vascular Regeneration

Abstract

Background — Previous studies have established that bone marrow–derived endothelial progenitor cells (EPCs) are present in the systemic circulation. In the current study, we investigated the hypothesis that gene transfer can be used to achieve phenotypic modulation of EPCs. Methods and Results — In vitro, ex vivo murine vascular endothelial growth factor (VEGF) 164 gene transfer augmented EPC proliferative activity and enhanced adhesion and incorporation of EPCs into quiescent as well as activated endothelial cell monolayers. To determine if such phenotypic modulation may facilitate therapeutic neovascularization, heterologous EPCs transduced with adenovirus encoding VEGF were administered to athymic nude mice with hindlimb ischemia; neovascularization and blood flow recovery were both improved, and limb necrosis/autoamputation were reduced by 63.7% in comparison with control animals. The dose of EPCs used for the in vivo experiments was 30 times less than that required in previous trials of EPC transplantation to improve ischemic limb salvage. Necropsy analysis of animals that received DiI-labeled VEGF-transduced EPCs confirmed that enhanced EPC incorporation demonstrated in vitro contributed to in vivo neovascularization as well. Conclusions — In vitro, VEGF EPC gene transfer enhances EPC proliferation, adhesion, and incorporation into endothelial cell monolayers. In vivo, gene-modified EPCs facilitate the strategy of cell transplantation to augment naturally impaired neovascularization in an animal model of experimentally induced limb ischemia.

Endothelial progenitor cells: Implications for cardiovascular disease

“…Already these variations in the coating strategy may have an influence on the results obtained by cell culture with respect to cell number, cell phenotype, and cell function. Another important factor regulating the fate of the plated cells is the cell culture media ranging from EBM-2 (23-25), medium-199 (22,26,27), to x-vivo-20 (28) as basal media, and 20% fetal calf serum (1), brain extract (1,26), to commercial available single quots of VEGF, insulin-like growth factor (IGF), basic fibroblast growth factor (23,25) as supplements. An identification criteria often used for EPCs in the culture of MNCs for 4 or 7 days is the double-positive staining of EPCs for endothelial-specific lectin (e.g., Ulex europaeus agglutini-1) and Dil-labeled acetylated low-density lipoproteins (Ac-LDL) (26,29,30).…”

Systemic inhibition of tumour angiogenesis by endothelial cell-based gene therapy

“…It has been reported that marrow-derived endothelial progenitor cells contribute to adult vasculogenesis (Tamura et al, 2004) and tumour angiogenesis (Rafii et al, 2002;Peters et al, 2005) by circulating through the vascular system and incorporating into the wall of newly formed vessels (Marchetti et al, 2002;Rafii and Lyden, 2003). Evidence that vasculogenesis is involved in neovascularisation has been found in studies on tumour vessels (Reyes et al, 2002), experimental retinopathy (Grant et al, 2002;Tomita et al, 2004;Butler et al, 2005), myocardial ischaemia (Kocher et al, 2001(Kocher et al, , 2006Botta et al, 2004), wound healing Crisa et al, 1999), and hindlimb ischaemia Kalka et al, 2000;Iwaguro et al, 2002). An important question that remains unanswered by the literature is whether circulating endothelial progenitor cells per se or their differentiated progeny are incorporated into the vascular wall .…”

Cells as vehicles for therapeutic genes to treat liver diseases

“…59 In an animal model of experimentally induced limb ischemia, Iwaguro el al. 60 showed that administration of EPC transduced with adenovirus encoding VEGF improved neovascularization and blood flow recovery and reduced amputation rate. In this study, EPC-mediated adenoviral VEGF gene therapy was able to achieve curative effects despite the use of subtherapeutical EPC doses.…”

“…In this study, EPC-mediated adenoviral VEGF gene therapy was able to achieve curative effects despite the use of subtherapeutical EPC doses. 60 Thus, combined EPC and gene therapy is an option to address the problem of limitations in the number of EPC that can be obtained for clinical applications.…”