title: Paracrine effect of canine allogenic umbilical cord blood-derived mesenchymal stromal cells mixed with beta-tricalcium phosphate on bone regeneration in ectopic implantations.
abstract: OBJECTIVE
  The aim of this study was to evaluate the paracrine effects of canine umbilical cord blood (cUCB) mesenchymal stromal cells (MSC) mixed with beta-tricalcium phosphate (beta-TCP) on bone regeneration in ectopic implantation.
  
  
  METHODS
  beta-TCP mixed with cUCB MSC (UCB-MSC group), cell lysates (cell lysate group) or a control (control group) were respectively implanted in a subcutaneous pouches in the back of beagle dogs . The implants were harvested 1, 4, 7, 14, 28, 56, 84 days after implantation. Histological findings and stain analyzes of tartrate-resistant acid phosphatase (TRACP) and assays of alkaline phosphatase (ALP) and TRACP were evaluated. The mRNA expression levels of interleukin-1 (IL-1), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), cyclooxygenase-2 (COX-2), vascular endothelial growth factor (VEGF) and transforming growth factor-beta (TGF-beta) were analyzed using semi-quantitative reverse transcription - polymerase chain reactions (RT-PCR). An enzyme-linked immunosorbent assay (ELISA) was used to confirm the protein expression levels of IL-6, COX-2, VEGF and TGF-beta.
  
  
  RESULTS
  TRACP-positive cells were observed in all groups 7 days after implantation. ALP and TRACP activities in the UCB-MSC group 84 days after implantation were significantly higher than those of the control (P>0.05). Histologic findings after 84 days showed that the osteoid matrix area in the UCB-MSC group was significantly larger than that of the control (P<0.05). The mRNAs levels of IL-1, IL-6 and VEGF in UCB-MSC and cell lysate groups on day 1 were up-regulated compared with the control. The protein levels of IL-6 and VEGF in the UCB-MSC group at day 1 were significantly higher than that of the other groups (P<0.05).
  
  
  CONCLUSIONS
  It is suggested that a significant release of cytokines by cUCB MSC, 1 day following implantation, could enhance bone regeneration.
authors.affiliation: Department of Veterinary Surgery, College of Veterinary Medicine, Seoul National University, Seoul, Korea.
authors.forename: Ye-Eun
authors.initials: YE
authors.lastname: Byeon
authors.forename: Hak-Hyun
authors.initials: HH
authors.lastname: Ryu
authors.forename: Sung Su
authors.initials: SS
authors.lastname: Park
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Koyama
authors.forename: Masanori
authors.initials: M
authors.lastname: Kikuchi
authors.forename: Wan Hee
authors.initials: WH
authors.lastname: Kim
authors.forename: Kyung-Sun
authors.initials: KS
authors.lastname: Kang
authors.forename: Oh-Kyeong
authors.initials: OK
authors.lastname: Kweon
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D001861:Bone Regeneration; D002130:Calcium Phosphates / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000096:biosynthesis / Q000235:genetics; D016207:Cytokines / Q000096:biosynthesis* / Q000235:genetics; D062109:Dermatologic Surgical Procedures; D004285:Dogs; D005312:Fetal Blood / Q000166:cytology; D007527:Isoenzymes / Q000378:metabolism; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D010012:Osteogenesis; D019899:Paracrine Communication; D012867:Skin / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D000071681:Tartrate-Resistant Acid Phosphatase; D014184:Transplantation, Homologous; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis / Q000235:genetics
chemical_list: D002130:Calcium Phosphates; D016207:Cytokines; D007527:Isoenzymes; D042461:Vascular Endothelial Growth Factor A; C485817:beta-tricalcium phosphate; D051546:Cyclooxygenase 2; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase