Current Approaches and Future Trends to Promote Tendon Repair

Abstract

Tendons are composed by extracellular collagen fibres arranged in regular arrays and are responsible to transmit tensile forces from a muscle to a bone. Due to their poor healing ability, in some cases tendons injuries are debilitating impairments that affect life quality among adult population worldwide. In the last years, attending to the social and economic concern associated to the high prevalence of tendons injuries and the limited success of the available current treatments, several scaffolds have been developed. Some of these scaffolds are intended to be used as graft-augmentation devices and others to fully replace a damaged tendon. The synthetic ones present superior mechanical characteristics compared to biological scaffolds. However, attending to the specific tendons physiology, even the synthetic scaffolds still don´t present the ideal mechanical properties to accomplish a complete and long-term functional tissue repair. Therefore, to enhance tendogenesis when using a tendon engineering approach, several methodologies have been developed to associate with scaffolds, including surface modification and cell seeding.

Application of Tendon Stem/Progenitor Cells and Platelet-Rich Plasma to Treat Tendon Injuries

“…Tendons are fibrous connective tissues containing 65–80% collagen type I, and elastin, proteoglycans, glycoproteins, and water in smaller amounts within tendon cells (6, 7). Since tendons link bones to muscles, they are designed to withstand mechanical loads, namely, the muscular loads.…”

Tendon injury and repair – A perspective on the basic mechanisms of tendon disease and future clinical therapy

“…This review is far from comprehensive, and we refer the interested reader to excellent focused reviews [187,[211][212][213].…”

Multiscale Poly-(ϵ-caprolactone) Scaffold Mimicking Non-linearity in Tendon Tissue Mechanics

“…Autografts provide benefits of initial mechanical stability, highest stiffness in tendon biomechanical constructs available, and reduction in the chance of late rupture; however, issues include surgical and donor site morbidity, finite availability, and inadequate revascularization. 3,6 Allografts, which demonstrate an advantage of no donor site morbidity and similar mechanical strength compared to autografts, have associated challenges including potential for disease transmission and bacterial infections, a limited donor pool, and an increased failure rate (up to 4 times higher) for young, active patients. 7 Thus, the market demand promotes synthetic scaffolds as an ideal solution within the regenerative engineering field.…”

“…7 Thus, the market demand promotes synthetic scaffolds as an ideal solution within the regenerative engineering field. 6 Regenerative engineering is the convergence of advanced biomaterials science with stem cell and developmental biology to repair, replace, or regenerate tissues to restore structure and function. 8–10 The area of regenerative engineering has the potential to be transformative in translational and clinical applications 10 because it converges multiple systems critical to effective cell-based therapies and tissue-related replacements.…”

“…6 However, synthetic regenerative medicine-based treatment options for tendon injuries still fall short in areas of: host tissue integration, mechanical stability, long term performance, physiological mechanical response of natural tendon, and balancing tissue remodeling and biodegradation of the material. 2 New therapeutic solutions must provide sufficient early biomechanical strength to withstand weight bearing motions during rehabilitation and introduction to patient day-to-day activities, serve as a scaffold to facilitate cell adhesion, differentiation, and development, remain biocompatible to the host, and be integrative to the graft connection points.…”