Tissue Engineering and Repair: A Vascular Problem
James Hoying (Regenerative Medicine/BIO5 Institute, University of Arizona)
(January 23, 2007 6:30 PM - 7:30 PM)
Tissue engineering and related cell-based therapies promise to not only facilitate tissue repair but also functionally replace damaged and diseased tissues. With tissue engineering, the goal is to fabricate tissue constructs, comprised of cells in a supportive environment, which mimic the function and/or architecture of the target tissue. The source of cells used in these constructs is the subject of considerable scientific discussion (and, in the case of stem cells, public discussion). However, regardless of the source and types of the cells incorporated into these engineered constructs, there remains a significant challenge in providing sufficient nutrients to the cells during fabrication and following implantation. Any tissue implant greater in dimension than a few millimeters is too big for nutrients to efficiently diffuse to the construct's cells from outside the construct. This is why the first successfully engineered tissues have been thin, sheets of cells (e.g. a simple skin). As advances give rise to more complicated, 3-dimensional tissue designs, the need for a strategy to support the health of these constructs becomes more urgent. In the body, the cardiovascular system serves to effectively deliver nutrients to any tissue. Therefore, the ability to form and incorporate blood vessels (particularly microvessels) into the constructs is critically important for construct health and function. We will discuss the particular challenges related to providing proper nutrition to constructed tissues and the strategies being employed to build vessels and vessel networks in the laboratory.