title: Mesenchymal-stem-cell-based experimental and clinical trials: current status and open questions.
abstract: BACKGROUND
  Mesenchymal stem cells (MSCs) possess remarkable self-renewal ability and are able to differentiate into various cell lineages. MSCs can also enhance tissue repair and angiogenesis through a paracrine mechanism. It has been recognized that these cells hold great promise for tissue regeneration and treatment of immune-related diseases.
  
  
  METHODS
  This review aims at discussing the mechanisms of MSC-mediated immunomodulation and tissue repair and the related clinical trials, with special emphasis on factors that influence the efficiency of MSC-based therapy, including the source of MSCs, cell passage, cell dose, timing and route of administration.
  
  
  CONCLUSIONS
  MSCs may facilitate tissue repair through cell replacement and/or improving the microenvironment by releasing growth factors. Some of these factors also mediate the immunomodulatory effects of MSCs. It is important to establish global guidelines, protocols and standards for production and clinical trials of MSCs, so that MSCs can become a therapeutic agent with a reliable efficacy and good safety.
authors: Organ Transplant Institute, Fuzhou General Hospital, Xiamen University, Fuzhou, China. tanjianming59@yahoo.com.cn
authors: Jin
authors: J
authors: Wang
authors: Lianming
authors: L
authors: Liao
authors: Jianming
authors: J
authors: Tan
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002465:Cell Movement; D049109:Cell Proliferation; D002986:Clinical Trials as Topic; D019317:Evidence-Based Medicine; D006801:Humans; D056747:Immunomodulation; D045164:Mesenchymal Stem Cell Transplantation / Q000009:adverse effects / Q000379:methods; D059630:Mesenchymal Stem Cells / Q000276:immunology / Q000378:metabolism; D019899:Paracrine Communication; D012038:Regeneration; D016896:Treatment Outcome