Functional Tissue Engineering for Repair of Load-Bearing Musculoskeletal Tissues: History and Perspective

Although who first defined tissue engineering and when this event first occurred in the 1980’s were only recently clarified [1], the enthusiasm for this treatment approach cannot be disputed. Traditional treatments have often been inadequate, leading clinicians and basic scientists to seek novel tissue engineering strategies using various cell, scaffold and bioreactor strategies (Figure 1). Tissue engineers routinely mix specialized as well as undifferentiated cells from various sources [2] with biologic, synthetic, and even hybrid scaffold biomaterials [3]. Cells can accelerate repair while scaffolds provide the tissue engineered construct (TEC) with mechanical and structural integrity and guide cell proliferation and differentiation and protein synthesis. Tissue engineers also design and adapt bioreactors to deliver mechanical and chemical stimuli to ensure viability and controlled cell preconditioning [4]. Once implanted, the fate of the repair rests on our ability to achieve desirable mechanical, structural, biological and clinical outcome measures. Unfortunately, many of these “design” or “success” criteria have not been agreed upon nor have the values been determined [5].