title: Articular cartilage repair: Current needs, methods and research directions.
abstract: Articular cartilage is a highly specialized tissue whose remarkable properties of deformability, resistance to mechanical loading, and low-friction gliding are essential to joint function. Due to its role as a cushion in bone articulation, articular cartilage is subject to many types of damaging insults, including decades of wear and tear, and acute joint injuries. However, this built-for-life tissue has a very poor intrinsic ability in adulthood to durably heal defects created by damaging insults. Consequently, articular cartilage progressively deteriorates and is eventually eroded, exposing the subchondral bone to the joint space, triggering inflammation and osteophyte development, and generating severe pain and joint incapacitation. The disease is called osteoarthritis (OA) and is today the leading cause of pain and disability in the human population. Researchers and clinicians have worked for decades to develop strategies to treat OA and restore joint function, but they are still far from being able to offer patients effective preventive or restorative treatments. Novel ideas, knowledge and technologies that nurture hope for major new breakthroughs are therefore sought. In this review, we first outline the composition, structure, and functional properties of normal human adult articular cartilage, as a reference for tissue conservation and regenerative strategies. We then describe current options that have been used clinically and in pre-clinical trials to treat osteoarthritic patients, and we discuss the benefits and inadequacies of these treatment options. Next, we review research efforts that are currently ongoing to try and achieve durable repair of functional cartilage tissue. Methods include engineering of tissue implants and we discuss the needs and options for tissue scaffolds, cell sources, and growth and differentiation factors to generate de novo or repair bona fide articular cartilage.
authors.affiliation: Department of Orthopaedics (Division of Sports Medicine), University of Miami, Miller School of Medicine, Miami, FL, 33136, USA; Diabetes Research Institute & Cell Transplant Center, University of Miami, Miller School of Medicine, Miami, FL, 33136, USA. Electronic address: dxc821@med.miami.edu.
authors.forename: Diego
authors.initials: D
authors.lastname: Correa
authors.affiliation: Department of Orthopaedics, Orthopaedic and Rheumatologic Institute, Cleveland Clinic, Cleveland, OH, 44195, USA; Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA. Electronic address: lietmas@ccf.org.
authors.forename: Steven A
authors.initials: SA
authors.lastname: Lietman
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000502:physiology*; D006801:Humans; D019736:Prostheses and Implants; D012038:Regeneration; D044968:Regenerative Medicine / Q000379:methods*; D023822:Tissue Engineering; D054457:Tissue Scaffolds / Q000737:chemistry
keywords: Articular cartilage; Chondrocyte; Osteoarthritis; Stem cells; Tissue engineering