Adipose-derived stem cells and rabbit bone regeneration: histomorphometric, immunohistochemical and mechanical characterization.
BACKGROUND
In the last few years, several attempts have been made to treat large bone loss, including the use of tissue engineering with osteoinductive scaffolds and cells. This study highlights the role of mesenchymal stem cells from adipose tissue (ASCs; adipose-derived stem cells) in a rabbit bone regeneration model.


METHODS
We compared the neoformed bone tissues achieved by treating critical tibial defects with either hydroxyapatite alone (HA, group I) or hydroxyapatite-autologous ASC constructs (ASCs-HA, group II), investigating their histomorphometric, immunohistochemical and biomechanical properties.


RESULTS
After eight weeks of follow-up, we observed advanced maturation and a spatial distribution of new bone that was more homogeneous in the inner parts of the pores in group II, not just along the walls (as seen in group I). The new tissue expressed osteogenic markers, and biomechanical tests suggested that the newly formed bone in group II had a higher mineral content than that in group I. Although variability in differentiation was observed among the different cell populations in vitro, no differences in bone healing were observed in vivo; the variability seen in vitro was probably due to local microenvironment effects.


CONCLUSIONS
Tibial defects treated with rabbit ASCs-HA showed an improved healing process when compared to the process that occurred when only the scaffold was used. We suggest that implanted ASCs ameliorate the bone reparative process either directly or by recruiting resident progenitor cells.
Department of Biomedical, Surgical, Dental Sciences, University of Milan, Via Vanvitelli, 32, 20129, Milan, Italy.
Elena
E
Arrigoni
Laura
L
de Girolamo
Alessia
A
Di Giancamillo
Deborah
D
Stanco
Claudia
C
Dellavia
Davide
D
Carnelli
Marino
M
Campagnol
Cinzia
C
Domeneghini
Anna T
AT
Brini
D000273:Adipose Tissue / Q000166:cytology*; D000818:Animals; D001696:Biomechanical Phenomena; D001861:Bone Regeneration / Q000502:physiology*; D007124:Immunoenzyme Techniques; D010012:Osteogenesis / Q000502:physiology; D011817:Rabbits; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000502:physiology*; D013314:Stress, Mechanical; D013977:Tibia / Q000601:surgery*