DEVELOPMENT OF TECHNOLOGIES AIDING LARGE-TISSUE ENGINEERING

There are many clinical situations in which a large tissue mass is req uired to replace tissue lost to surgical resection (e.g. mastectomy). It is possible that autologous cell transplantation on biodegradable p olymer matrices may provide a new therapy to engineer large tissue whi ch can be used to treat these patients. A number of challenges must be met to engineer a large soft tissue mass. These include the design of (1) a structural framework to maintain a space for tissue development , (2) a space-filling matrix which provides for localization of transp lanted cells, and (3) a stragegyto enhance vascularization of the form ing tissue. in this paper we provide an overview of several technologi es which are under development to address these issues. Specifically, support matrices to maintain a space for tissue development have been fabricated from polymers of lactide and glycolide. The ability of thes e structures to resist compressive forces was regulated by a ratio lac tide to glycolide in the polymer. Smooth muscle cell seeding onto poly glycolide fiber-based matrices has been optimized to allow formation o f new tissues in vitro and in vivo. Finally, polymer microsphere drug delivery technology is being developed to release vascular endothelial growth factor (VEGF), a potent angiogenic molecule, at the site of ti ssue formation. This strategy, which combines several different techno logies, may ultimately allow for engineering of large soft tissues.