Tissue engineering is a strategy where biologically compatible scaffolds are implanted in the body at the site where new tissue is to be formed. If the scaffold is in the geometric shape of the tissue that needs to be generated, and the scaffold attracts cells the outcome is new tissue in the shape desired. If the newly forming tissue is subjected to exercise as it forms, the outcome can be new functional engineered issue.
Millions of patients have been treated with some form of tissue engineered devices, yet the field is in its infancy. The primary success stories have been with soft tissue regeneration.
McGowan Institute for Regenerative Medicine
Bridgeside Point II
450 Technology Drive
Pittsburgh, PA 15219
If a patient's food tube or airway is damaged, scar tissue can form, which makes breathing or swallowing impossible. Currently, there are no treatments for these conditions other than to remove the damaged areas. McGowan Institute researchers—led by Stephen Badylak, MD—are working on a method that uses natural scaffolds seeded with the patient's own cells to encourage the growth of healthy tissue instead of scar tissue. In early studies, a damaged section of the food tube was replaced with a specially formed scaffold constructed from a material already being used in humans. Within 90 days, the scaffold was replaced with functional tissue.
Cells in the peripheral nervous system can regrow, but they sometimes have trouble linking up with each other, which is essential to restore feeling and function. To aid peripheral nerve regeneration, McGowan Institute faculty member Kacey G. Marra, PhD, and researchers have developed scaffolds made of FDA-approved biodegradable polymers and protein beads. Channels in the scaffolds act as guides for axons, the long arms of nerve cells, to grow longer and in the right directions. In early studies, a nerve guide seeded with stem cells derived from fat restored some hind leg mobility to paralyzed rats.
The reconstruction of skeletal muscle tissue either lost by traumatic injury, tumor ablation, or due to congenital abnormalities is hampered by the lack of availability of functional substitutes to this native tissue. Initial studies have focused on the use of small intestinal submucosa scaffolds to replace partial lost gastrocnemius muscle and Achilles tendon. These studies have shown that this material is capable of stimulating restoration of significant muscle mass and restitution of the musclulotendinous junction restoring functionality to a damaged limb. This new muscle growth is both contractile and innervated and comprises a mixed muscle fiber population similar to the native muscle that was lost. Research in this area is conducted by McGowan Institute affiliated faculty members Stephen Badylak, MD, J. Peter Rubin, MD, FACS, Neill Turner, PhD, and Michael Boninger, MD.
Orthopaedic injuries can compromise mobility and hinder quality of life, and not just for professional athletes. At the McGowan Institute for Regenerative Medicine, we've been studying the forces on bones and joints for a long time. We’ve been working on:
Organ engineering, as opposed to tissue engineering, poses significant challenges including the requirement for an immediately functional vascular network, functional parenchymal cells, and lymphatic and innervation potential. In recent years a promising approach for functional organ replacement has emerged: the decellularization of whole organs, providing an acellular three-dimensional scaffold composed of extracellular matrix (ECM). Importantly, the scaffold has been shown to retain the native vascular network of the organ. The long-term goal of this work is to establish the decellularization, recellularization with autologous cells (thus avoiding the need for subsequent immunosuppression), and transplantation criteria necessary to produce functional bioengineered organs for clinical translation. McGowan Institute researchers in the Badylak lab specifically focus on whole liver and heart regeneration.