Analysis of Serum-Free Culture of Umbilical Cord Blood-derived Endothelial Cells

The success of therapeutic vascularisation and tissue engineering will rely on our ability to create vascular networks using human endothelial cells (ECs) that can be obtained readily, can be expanded safely ex vivo, and can produce robust vasculogenic activity in vivo. The lack of sufficient vasculature for the supply with nutrients and oxygen is still a limiting factor for the successful implantation of tissue engineered constructs and leads in many cases to the failure of the implant. A strategy to improve vascularisation of bioengineered tissues might be the incorporation of or vascular-like structures in the tissue-engineered constructs and then to implant the material at the desired site. Prospective cell therapy will require standardised, reproducible, pathogen-free culture conditions. Along this aim, we sought to elaborate serum-free conditions for expansion and cryo-preservation of umbilical cord blood derived endothelial outgrowth cells (UCB-OECs). We compared their expandibility in standard serum-containing medium versus a panel of commercial, serum-free, chemically defined maintenance or expansion media for ECs. Proliferation of OECs was fast under standard culture with serum, but modest or absent in serum-free media, even upon supplementation with a battery of endothelial growth factors. We performed genome wide gene array analysis with UCB-OECs to identify signalling pathways that are activated in serum conditions but not in chemically defined media. We report conditions for serum-free culture as well as xeno-free cryo-preservation of UCB-OECs.

The study is supported by European Commission FP6 grant 'CRYSTAL'.

Endothelial cells - regenerative medicine - therapeutic vascularisation - tissue engineering - umbilical cord blood