title: Cryopreserved human adipogenic-differentiated pre-adipocytes: a potential new source for adipose tissue regeneration.
abstract: BACKGROUND
  Previously, we have shown that in vitro adipogenic differentiation of pre-adipocytes before implantation can enhance in vivo adipose tissue formation. For large-scale adipose tissue engineering or repeat procedures, cryopreservation of fat grafts has been commonly used in recent years. However, the feasibility of cryopreservation of adipogenic differentiated pre-adipocytes has not been investigated.
  
  
  METHODS
  To examine the impact of cryopreservation on the adipogenic functions of adipogenic-differentiated pre-adipocytes, freeze-thawed adipocytes were compared with fresh differentiated adipocytes in vitro and in vivo. Adipogenic function was assessed by Oil red O staining, ELISA analysis of leptin secretion and RT-PCR of adipogenic-related genes. After transplantation, adipose tissue formation was assessed by histomorphologic and volumetric analysis.
  
  
  RESULTS
  Freeze-thawed adipocytes constantly showed typical adipogenic functions in terms of lipid content, leptin secretion and adipogenic gene expression, as well as good viability. Importantly, implants derived from freeze-thawed adipocytes were successfully developed to adipose tissue and newly formed adipose tissues were similar to those developed from fresh differentiated adipocytes, based on histomorphologic and volumetric analysis. In addition, CD34-positive endothelial cells were detected in implants. These results demonstrate that the specific characters of adipogenic-differentiated pre-adipocytes are successfully conserved after cryopreservation without any significant alteration.
  
  
  CONCLUSIONS
  Cryopreservation of adipogenic-differentiated pre-adipocytes is a feasible method and extends their clinical use in adipose tissue-engineering applications and transplantation.
authors.affiliation: Anterogen Co Ltd, Seoul, Korea.
authors.forename: M  H
authors.initials: M
authors.lastname: Kim
authors.forename: I
authors.initials: I
authors.lastname: Kim
authors.forename: S-H
authors.initials: SH
authors.lastname: Kim
authors.forename: M  K
authors.initials: M
authors.lastname: Jung
authors.forename: S
authors.initials: S
authors.lastname: Han
authors.forename: J  E
authors.initials: J
authors.lastname: Lee
authors.forename: J-S
authors.initials: JS
authors.lastname: Nam
authors.forename: S-K
authors.initials: SK
authors.lastname: Lee
authors.forename: S  I
authors.initials: S
authors.lastname: Bang
mesh_terms: D017667:Adipocytes / Q000166:cytology / Q000502:physiology* / Q000637:transplantation*; D050156:Adipogenesis / Q000235:genetics; D000273:Adipose Tissue / Q000166:cytology / Q000502:physiology / Q000637:transplantation*; D000818:Animals; D018952:Antigens, CD34 / Q000276:immunology; D001391:Azo Compounds; D018929:Cell Culture Techniques / Q000379:methods; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D015925:Cryopreservation / Q000379:methods*; D004121:Dimethyl Sulfoxide; D042783:Endothelial Cells / Q000166:cytology / Q000276:immunology; D005786:Gene Expression Regulation / Q000235:genetics; D006801:Humans; D020738:Leptin / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D012038:Regeneration / Q000502:physiology; D033581:Stem Cell Transplantation / Q000379:methods*; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*; D023822:Tissue Engineering / Q000379:methods; D014183:Transplantation, Heterologous