title: Reprogramming of blood cells into induced pluripotent stem cells as a new cell source for cartilage repair.
abstract: BACKGROUND
  An attempt was made to reprogram peripheral blood cells into human induced pluripotent stem cell (hiPSCs) as a new cell source for cartilage repair.
  
  
  METHODS
  We generated chondrogenic lineage from human peripheral blood via hiPSCs using an integration-free method. Peripheral blood cells were either obtained from a human blood bank or freshly collected from volunteers. After transforming peripheral blood cells into iPSCs, the newly derived iPSCs were further characterized through karyotype analysis, pluripotency gene expression and cell differentiation ability. iPSCs were differentiated through multiple steps, including embryoid body formation, hiPSC-mesenchymal stem cell (MSC)-like cell expansion, and chondrogenic induction for 21 days. Chondrocyte phenotype was then assessed by morphological, histological and biochemical analysis, as well as the chondrogenic expression.
  
  
  RESULTS
  hiPSCs derived from peripheral blood cells were successfully generated, and were characterized by fluorescent immunostaining of pluripotent markers and teratoma formation in vivo. Flow cytometric analysis showed that MSC markers CD73 and CD105 were present in monolayer cultured hiPSC-MSC-like cells. Both alcian blue and toluidine blue staining of hiPSC-MSC-chondrogenic pellets showed as positive. Immunohistochemistry of collagen II and X staining of the pellets were also positive. The sulfated glycosaminoglycan content was significantly increased, and the expression levels of the chondrogenic markers COL2, COL10, COL9 and AGGRECAN were significantly higher in chondrogenic pellets than in undifferentiated cells. These results indicated that peripheral blood cells could be a potential source for differentiation into chondrogenic lineage in vitro via generation of mesenchymal progenitor cells.
  
  
  CONCLUSIONS
  This study supports the potential applications of utilizing peripheral blood cells in generating seed cells for cartilage regenerative medicine in a patient-specific and cost-effective approach.
authors.affiliation: Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China. yueyinglee2010@hotmail.com.
authors.forename: Yueying
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Orthopedics, Beijing Chao-Yang Hospital, Capital Medical University, GongTiNanLu 8#, Chaoyang District, Beijing, 100020, China. tieliumd@hotmail.com.
authors.forename: Tie
authors.initials: T
authors.lastname: Liu
authors.affiliation: Department of Orthopedics, Beijing Chao-Yang Hospital, Capital Medical University, GongTiNanLu 8#, Chaoyang District, Beijing, 100020, China. nick_profession_cn@yahoo.com.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Van Halm-Lutterodt
authors.affiliation: Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China. chenjiayu@tongji.edu.cn.
authors.forename: JiaYu
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Orthopedics, Beijing Chao-Yang Hospital, Capital Medical University, GongTiNanLu 8#, Chaoyang District, Beijing, 100020, China. qjsurex@sohu.com.
authors.forename: Qingjun
authors.initials: Q
authors.lastname: Su
authors.affiliation: Department of Orthopedics, Beijing Chao-Yang Hospital, Capital Medical University, GongTiNanLu 8#, Chaoyang District, Beijing, 100020, China. Spinesurgeon@163.com.
authors.forename: Yong
authors.initials: Y
authors.lastname: Hai
mesh_terms: D000328:Adult; D000818:Animals; D002356:Cartilage / Q000473:pathology; D002454:Cell Differentiation; D002478:Cells, Cultured; D065150:Cellular Reprogramming; D000067470:Cellular Reprogramming Techniques; D019902:Chondrocytes / Q000502:physiology; D020219:Chondrogenesis; D005260:Female; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000502:physiology*; D007963:Leukocytes, Mononuclear / Q000502:physiology*; D008297:Male; D016513:Mice, SCID; D044968:Regenerative Medicine; D033581:Stem Cell Transplantation; D055815:Young Adult