title: Autologous in vivo adipose tissue engineering in hyaluronan-based gels--a pilot study.
abstract: BACKGROUND
  There is a major clinical need for strategies for adequately reconstructing the soft tissue defects found after deep burns, tumor resection, or trauma. A promising solution is adipose tissue engineering with preadipocytes, stem-cell derived precursors of the adipose tissue, implanted within biomaterials. This pilot study evaluated hyaluronan gels mixed with autologous undifferentiated preadipocytes in a pig model for their potency to generate new fat.
  
  
  METHODS
  Preadipocytes were isolated from intra-abdominal pig fat by collagenase digestion, plated on fibronectin-coated culture dishes in Dulbecco's modified Eagle medium/Ham's F12 (Biochrom, Berlin, Germany) combined with 10% pig serum, expanded, and mixed with hyaluronan gel. Two types of gels with varying degrees of amidation of the carboxyl groups were tested (HYADD3, HYADD4). Cell-loaded gels and unseeded controls were injected subcutaneously into the ears of three pigs, explanted at 6 wk, and analyzed histologically.
  
  
  RESULTS
  Both cell-loaded specimens were detected macroscopically. They demonstrated a slight volume effect with limited stability after 6 wk. Unloaded HYADD3 and HYADD4 controls could not be identified at the time of explantation. Histology of HYADD3 revealed islets of mature adipocytes and vessels embedded in fat tissue surrounded by gel. In contrast, no fat formation was found in HYADD4 gels when implanted in the ear.
  
  
  CONCLUSIONS
  Histological findings demonstrate that HYADD3 is a promising gel for generating adipose tissue. Even though HYADD3 might be a potential material for the reconstruction of small tissue defects, the question remains as to whether the adipose tissue within the gel is attributable to preadipocyte maturation or ingrowth from neighboring tissue.
authors.affiliation: Department of Plastic Surgery and Hand Surgery-Burn Center, University Hospital of the Aachen University of Technology RWTH, Aachen, Germany. hemmrich@gmx.de
authors.forename: Karsten
authors.initials: K
authors.lastname: Hemmrich
authors.forename: Karlien
authors.initials: K
authors.lastname: Van de Sijpe
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Rhodes
authors.forename: John A
authors.initials: JA
authors.lastname: Hunt
authors.forename: Chiara
authors.initials: C
authors.lastname: Di Bartolo
authors.forename: Norbert
authors.initials: N
authors.lastname: Pallua
authors.forename: Phillip
authors.initials: P
authors.lastname: Blondeel
authors.forename: Dennis
authors.initials: D
authors.lastname: von Heimburg
mesh_terms: D050153:Abdominal Fat / Q000166:cytology / Q000637:transplantation*; D017667:Adipocytes / Q000166:cytology*; D000818:Animals; D002454:Cell Differentiation; D002469:Cell Separation; D002478:Cells, Cultured; D005782:Gels; D006820:Hyaluronic Acid / Q000031:analogs & derivatives / Q000737:chemistry; D010865:Pilot Projects; D013234:Stem Cells / Q000166:cytology*; D013552:Swine; D023822:Tissue Engineering / Q000379:methods*; D014182:Transplantation, Autologous
chemical_list: D005782:Gels; D006820:Hyaluronic Acid