title: Cell transplantation as an initiator of endogenous stem cell-based tissue repair.
abstract: OBJECTIVE
  The aim of this review is to summarize recent findings of endogenous cell-based tissue repair triggered by a multitude of approaches, especially stem cell therapy.
  
  
  RESULTS
  The emerging evidence has demonstrated that an important role of transplanted cells is to act as an initiator to trigger endogenous stem cell-mediated tissue repair after injury. Multiple approaches may orchestrate endogenous regeneration. The low efficacy of endogenous stem cells may be due to deficiency of cytokines to activate and induce endogenous stem cell homing, relatively insufficient endogenous stem cell pool, diseases or aging-related dysfunction of endogenous stem cells, and hostile microenvironments that limit the capacity of endogenous stem cells to repair damaged tissue. In certain situations, external stimulation and/or exogenous stem cells may be required to catalyze the repair.
  
  
  CONCLUSIONS
  Endogenous stem cells are playing an important role in tissue repair. An important role of transplanted cells is to act as an initiator to trigger endogenous stem cell-based tissue repair.
authors.affiliation: Integrated Medical Sciences, Northeast Ohio Medical University, Rootstown, Ohio 44272, USA. fdong@neomed.edu
authors.forename: Feng
authors.initials: F
authors.lastname: Dong
authors.forename: Arnold I
authors.initials: AI
authors.lastname: Caplan
mesh_terms: D017690:Cell Transplantation; D006801:Humans; D045164:Mesenchymal Stem Cell Transplantation; D012038:Regeneration; D033581:Stem Cell Transplantation; D013234:Stem Cells; D014945:Wound Healing