title: Prevalence of endogenous CD34+ adipose stem cells predicts human fat graft retention in a xenograft model.
abstract: BACKGROUND
  Fat grafting is a promising technique for soft-tissue augmentation, although graft retention is highly unpredictable and factors that affect graft survival have not been well defined. Because of their capacity for differentiation and growth factor release, adipose-derived stem cells may have a key role in graft healing. The authors' objective was to determine whether biological properties of adipose-derived stem cells present within human fat would correlate with in vivo outcomes of graft volume retention.
  
  
  METHODS
  Lipoaspirate from eight human subjects was processed using a standardized centrifugation technique and then injected subcutaneously into the flanks of 6-week-old athymic nude mice. Graft masses and volumes were measured, and histologic evaluation, including CD31+ staining for vessels, was performed 8 weeks after transplantation. Stromal vascular fraction isolated at the time of harvest from each subject was analyzed for surface markers by multiparameter flow cytometry, and also assessed for proliferation, differentiation capacity, and normoxic/hypoxic vascular endothelial growth factor secretion.
  
  
  RESULTS
  Wide variation in percentage of CD34+ progenitors within the stromal vascular fraction was noted among subjects and averaged 21.3 ± 15 percent (mean ± SD). Proliferation rates and adipogenic potential among stromal vascular fraction cells demonstrated moderate interpatient variability. In mouse xenograft studies, retention volumes ranged from approximately 36 to 68 percent after 8 weeks, with an overall average of 52 ± 11 percent. A strong correlation (r = 0.78, slope = 0.76, p < 0.05) existed between stromal vascular fraction percentage of CD34+ progenitors and high graft retention.
  
  
  CONCLUSIONS
  Inherent biological differences in adipose tissue exist between patients. In particular, concentration of CD34+ progenitor cells within the stromal vascular fraction may be one of the factors used to predict human fat graft retention.
authors.affiliation: Pittsburgh, Pa. From the Departments of Plastic Surgery and Bioengineering, University of Pittsburgh; the University of Pittsburgh Cancer Institute; and the McGowan Institute for Regenerative Medicine.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Philips
authors.forename: Tara L
authors.initials: TL
authors.lastname: Grahovac
authors.forename: Jolene E
authors.initials: JE
authors.lastname: Valentin
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Chung
authors.forename: Jacqueline M
authors.initials: JM
authors.lastname: Bliley
authors.forename: Melanie E
authors.initials: ME
authors.lastname: Pfeifer
authors.forename: Sohini B
authors.initials: SB
authors.lastname: Roy
authors.forename: Stephanie
authors.initials: S
authors.lastname: Dreifuss
authors.forename: Arta
authors.initials: A
authors.lastname: Kelmendi-Doko
authors.forename: Russell E
authors.initials: RE
authors.lastname: Kling
authors.forename: Sudheer K
authors.initials: SK
authors.lastname: Ravuri
authors.forename: Kacey G
authors.initials: KG
authors.lastname: Marra
authors.forename: Vera S
authors.initials: VS
authors.lastname: Donnenberg
authors.forename: Albert D
authors.initials: AD
authors.lastname: Donnenberg
authors.forename: J Peter
authors.initials: JP
authors.lastname: Rubin
mesh_terms: D050156:Adipogenesis; D000328:Adult; D053687:Adult Stem Cells / Q000378:metabolism / Q000637:transplantation*; D000818:Animals; D018952:Antigens, CD34 / Q000378:metabolism; D002454:Cell Differentiation; D005260:Female; D006085:Graft Survival; D006801:Humans; D007279:Injections, Subcutaneous; D008297:Male; D051379:Mice; D008819:Mice, Nude; D023421:Models, Animal; D011237:Predictive Value of Tests; D015995:Prevalence; D050507:Subcutaneous Fat, Abdominal / Q000166:cytology*; D013518:Surgery, Plastic / Q000379:methods*; D014183:Transplantation, Heterologous / Q000379:methods*; D055815:Young Adult
chemical_list: D018952:Antigens, CD34