Tendon tissue engineering: progress, challenges, and translation to the clinic

Abstract

The tissue engineering field has made great strides in understanding how different aspects of tissue engineered constructs (TECs) and the culture process affect final tendon repair. However, there remain significant challenges in developing strategies that will lead to a clinically effective and commercially successful product. In an effort to increase repair quality, a better understanding of normal development, and how it differs from adult tendon healing, may provide strategies to improve tissue engineering. As tendon tissue engineering continues to improve, the field needs to employ more clinically relevant models of tendon injury such as degenerative tendons. We need to translate successes to larger animal models to begin exploring the clinical implications of our treatments. By advancing the models used to validate our TECs, we can help convince our toughest customer, the surgeon, that our products will be clinically efficacious. As we address these challenges in musculoskeletal tissue engineering, the field still needs to address the commercialization of products developed in the laboratory. TEC commercialization faces numerous challenges because each injury and patient is unique. This review aims to provide tissue engineers with a summary of important issues related to engineering tendon repairs and potential strategies for producing clinically successful products.

Figure 1. Tissue Engineering Decision Tree (TEDT)

With a near infinite number of possible TEC factors, we need to identify a process to limit those possibilities. We propose to establish relationships among TEC factors and evaluation milestones during all experimental stages and halt experiments that will not lead to improved repair since each successive experimental stage increases time and cost. The goal of our process is reduce the investment (time and money) required for creating effective repairs.

Figure 2

Schematic of potential mechanisms leading to tendon degeneration^{, , ,} .

Figure 3

A roadmap for product development used by our group to bring a tissue engineered TEC from the bench top to bedside including device development for surgical implantation and business plan. Mary Beth Privitera, MoD, Co-Director of the University of Cincinnati Medical Device Innovation and Entrepreneurship Program, and Jeffrey Johnson, PhD, Director of the University of Cincinnati Research Design Innovation and Entrepreneurship Program, helped with the creation this figure.