RFP-bAECs are selected from bAECs transfected using lentivirus expressing RFP using Puromycin. The cells are shipped in a frozen vial(the cells are provided @ passage 2). Endothelial Growth Medium is recommended for the expansion of RFP-bAECs and these cells can be propagated to at least 12 population doubling times without losing their morphologic and phenotypic characteristics when cultured following the detailed protocol described below.