Grants We Funded

Abstract
Tissue engineering seeks to restore and/or replace the form and function of damaged tissue and promises to revolutionize treatment in medical fields such as cardiovascular, transplant, oncologic and reconstructive surgery. Fabrication is based upon the ideal scaffold that forms the framework and suitable environment on which tissue is regenerated. A major obstacle to creating large, clinically relevant constructs remains adequate and timely vascularization. Currently available tissue replacements are avascular grafts and therefore, diffusion dependent, limiting the thickness with which they can be fabricated as cells beyond 100-200 µm from the nearest blood supply will likely experience necrosis. In order to address this critical limitation, we propose fabrication of a "pre-vascularized" scaffold that will facilitate cell survival by providing immediate perfusion following microsurgical anastomosis to the host vasculature. In preliminary work, constructs were fabricated and seeded with human umbilical vein endothelial cells (HUVEC) and cultured under both static and dynamic conditions for four days, resulting in successful engraftment of the cells along the microchannel. For the proposed study, custom-made, 1mm diameter, single-channel tissue scaffolds will be fabricated using type I collagen as the bulk material and Pluronic F127 and carbohydrate "glass" as sacrificial microfibers. Channels within the constructs will be seeded with HUVECs or HUVEC and Human Aortic Smooth Muscle Cells (HASMC) and cultured under conventional static conditions and within a gravity-driven perfusion bioreactor for 7 and 14 days to optimize confluence of the endothelial lining within. After confluence is achieved, scaffolds will be microsurgically anastomosed to the femoral artery and vein of heparinized adult nude rats and in vivo patency assessed at 4 hours, 1 day, 3 days, and 7days. Successful fabrication and in vivo anastomosis of a prevascularized scaffold would represent a quantum leap in the field of tissue engineering, providing a tissue replacement product with its own inherent vascularity that could be directly anastomosed to host vasculature.

Biography
Dr. Jason Spector is a nationally recognized clinician, researcher and educator. He holds two patents, and has been an integral part several Cornell University-Weill Cornell Medical College translational research teams. He participates in the NIH and Howard Hughes Medical Institute sponsored Clinical Summer Immersion for Biomedical Engineering Program, mentoring engineering doctoral students. Since 2007, he has been a lecturer at Cornell University's Biomedical Engineering Science and Technology course, "Approaches to Problems in Human Needs." Dr. Spector serves as an Ad-Hoc reviewer for six prestigious medical journals, and has presented at national and international medical meetings. He recently served as Moderator of the Emerging Technologies Section, at the American Surgical Congress in 2011.