Blood outgrowth endothelial cell migration and trapping in vivo: a window into gene therapy

Abstract

Human blood outgrowth endothelial cells (hBOEC) may be useful delivery-cells for gene therapy. hBOEC have high expansion capacity and stable phenotype. If incorporated into blood vessels, hBOEC could release therapeutic agents directly into the blood stream. However, little is known about lodging and homing of hBOEC in vivo. We examined the homing patterns of hBOEC in mice, and explored extending cell-based FVIII gene therapy from mice to larger animals. hBOEC were injected into NOD/SCID mice to determine where they localize, how localization changes over time and if there were toxic effects on host organs. The presence of hBOEC in mouse organs was determined by qPCR and immunofluorescence microscopy. hBOEC lodged most notably in mouse lungs at 3 h, but by 24 h there were no differences between 9 organs. hBOEC longevity was assessed up to 7 months in vivo. hBOEC expanded well and then plateaued in vivo. hBOEC from older cultures expanded equally well in vivo as younger. hBOEC caused no noticeable organ toxicity up to 3 days post-injection. When mice were pretreated with antibodies to E-selectin, P-selectin or anti-α4 integrin prior to hBOEC injection, the number of hBOEC in lungs at 3h was inhibited. Preliminary studies infusing hemophilic dogs with autologous canine BOEC over-expressing FVIII (B-domain deleted) showed improvement in whole blood clotting times (WBCT). In conclusion, the survivability, expandability and lack of toxicity of BOEC in vivo indicate that they may be valuable host cells for gene therapy.

MRI assessment of blood outgrowth endothelial cell homing using cationic magnetoliposomes

“…Based on histological examination of multiple tissues, Lin et al [27] observed the presence of human BOECs in spleen and bone marrow 5 months after administration to NOD/SCID mice. In a later study from the same group, somewhat different results were obtained, showing human BOECs predominantly being lodged in mouse lungs during the first hours after administration, followed by an evenly distributed presence of BOECs in 9 mouse organs after the first day up to seven months after injection [31]. In the same week (2nd column) and 2 weeks (3rd column) after cell injection.…”

Outgrowth Endothelial Cells: Characterization and Their Potential for Reversing Ischemic Retinopathy

“…This relatively short time was chosen because the oxygen-induced retinopathy model reproduces an acute ischemic pathology; however, it was recently demonstrated that OECs injected into the systemic circulation of NOD/SCID mice are able to lodge and survive in nine different vascular beds for up to 7 months after injection without inducing any thrombosis or infarcts. 37 Taken together, OECs are a novel and exciting prospect for vascular stem cell therapy for ischemic retinopathies, especially because they show clear reparative and vessel formation properties while having limited replicative potential, thereby reducing the neoplastic risk associated with other stem cell therapies.…”

Accessory Cells in Tumor Angiogenesis — Tumor-Associated Pericytes

“…This idea is supported by previous work using progenitor ECs [85][86][87], and more recently, PCs [50] to deliver anti-angiogenic gene therapy.…”