Qualification of labeled Endothelial Progenitor cells for tracking in the context of tissue engineering

In order to track location and distribution of endothelial cells (ECs) within scaffolds, we chose lentiPGK-TdTomato transduction of human Endothelial Progenitor Cells (EPCs). Because transduction could have a functional impact on cell behaviour, we checked different parameters for qualification of labeled-EPCs. After isolation and expansion, EPCs were transduced with the lentiviral vector containing the TdTomato protein gene. Conventional karyotyping, differentiation capacity, viability, proliferation assays and functional assays were performed with labeled and unlabeled EPCs. Results show that cell labeling did not affect cell adhesion nor induce cell death. Cell labeling did not induce more chromosomal aberrations. Phenotypical characterization was not affected. In the context of tissue engineering applications, labeled EPCs maintained their ability to line scaffolds, withstand physiological arterial shear stress and form tubular networks in co-cultures with human osteoblast progenitor cells. So it is possible to label human EPCs with TdTomato without affecting their behaviour by the transduction procedure. This creates an important tool for vascular and bone tissue engineering