title: Stem cells in degenerative orthopaedic pathologies: effects of aging on therapeutic potential.
abstract: OBJECTIVE
  The purpose of this study was to summarize the current evidence on the use of stem cells in the elderly population with degenerative orthopaedic pathologies and to highlight the pathophysiologic mechanisms behind today's therapeutic challenges in stem cell-based regeneration of destructed tissues in the elderly patients with osteoarthritis (OA), degenerative disc disease (DDD), and tendinopathies.
  
  
  METHODS
  Clinical and basic science studies that report the use of stem cells in the elderly patients with OA, DDD, and tendinopathies were identified using a PubMed search. The studies published in English have been assessed, and the best and most recent evidence was included in the current study.
  
  
  RESULTS
  Evidence suggests that, although short-term results regarding the effects of stem cell therapy in degenerative orthopaedic pathologies can be promising, stem cell therapies do not appear to reverse age-related tissue degeneration. Causes of suboptimal outcomes can be attributed to the decrease in the therapeutic potential of aged stem cell populations and the regenerative capacity of these cells, which might be negatively influenced in an aged microenvironment within the degenerated tissues of elderly patients with OA, DDD, and tendinopathies.
  
  
  CONCLUSIONS
  Clinical protocols guiding the use of stem cells in the elderly patient population are still under development, and high-level randomized controlled trials with long-term outcomes are lacking. Understanding the consequences of age-related changes in stem cell function and responsiveness of the in vivo microenvironment to stem cells is critical when designing cell-based therapies for elderly patients with degenerative orthopaedic pathologies.
authors: Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, 3471 Fifth Avenue, Suite 1011, Pittsburgh, PA, 15213, USA. atesokk@upmc.edu.
authors: Kivanc
authors: K
authors: Atesok
authors: Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, 3471 Fifth Avenue, Suite 1011, Pittsburgh, PA, 15213, USA.
authors: Freddie H
authors: FH
authors: Fu
authors: Department of Cartilage Regeneration, Tokyo Medical and Dental University, Tokyo, Japan.
authors: Ichiro
authors: I
authors: Sekiya
authors: Center for Biological Engineering, Wolfson School, Loughborough University, Loughborough, UK.|Translational Center for Regenerative Medicine (TRM), University Leipzig, Leipzig, Germany.
authors: Alexandra
authors: A
authors: Stolzing
authors: Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
authors: Mitsuo
authors: M
authors: Ochi
authors: Sports Medicine and Shoulder Service, Hospital for Special Surgery, New York, NY, USA.
authors: Scott A
authors: SA
authors: Rodeo
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology; D048091:Guided Tissue Regeneration; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000503:physiopathology / Q000628:therapy*; D010003:Osteoarthritis / Q000503:physiopathology / Q000628:therapy*; D033581:Stem Cell Transplantation; D052256:Tendinopathy / Q000503:physiopathology / Q000628:therapy*
keywords: Aging; Degenerative orthopaedic pathologies; Osteoarthritis; Stem cells; Tissue regeneration