Perfusion bioreactor culture of human adipose-derived stromal cells on decellularized adipose tissue scaffolds enhances in vivo adipose tissue regeneration

Tissue-engineering approaches hold promise to address the need in plastic and reconstructive surgery for new therapies that promote stable adipose tissue regeneration. Previous studies have demonstrated the potential of combining decellularized adipose tissue (DAT) scaffolds with adipose-derived stromal cells (ASCs) for volume augmentation applications. With the goal of enhancing in vivo angiogenesis and adipogenesis, this study evaluated the effects of culturing human ASCs on DAT scaffolds within a perfusion bioreactor. Using this system, the impact of both dynamic culture and hypoxic preconditioning were explored in vitro and in vivo. Initial studies compared the effects of 14 days of culture within the perfusion bioreactor under hypoxia (2% O-2) or normoxia (similar to 20% O-2) on human ASC expansion and expression of hypoxia inducible factor-1 alpha (HIF-1 alpha) in vitro relative to static cultured controls. The findings indicated that culturing within the bioreactor under hypoxia significantly increased ASC proliferation on the DAT, with a higher cell density observed in the scaffold periphery. Subsequent characterization in a subcutaneous implant model in athymic nude mice revealed that in vivo angiogenesis and adipogenesis were markedly enhanced when the ASCs were cultured on the DAT within the perfusion bioreactor under hypoxia for 14 days prior to implantation relative to the other culture conditions, as well as freshly seeded and unseeded DAT control groups. Overall, dynamic culture within the perfusion bioreactor system under hypoxia represents a promising approach for preconditioning ASCs on DAT scaffolds to enhance their capacity to stimulate angiogenesis and host-derived adipose tissue regeneration.