Objective The adipose tissue represents an important reservoir of stem cells. There are few studies in the literature with which to histologically evaluate whether or not the adipose tissue graft is really a safe option to achieve bone repair. This study histologically analyzed the effect of fragmented autogenous adipose tissue grafts on bone healing in surgically created, critical-size defects (CSD) in a rabbit’s calvaria. Study design Forty-two New Zealand rabbits were used in this study. CSD that were 15 mm in diameter were created in the calvarium of each animal. The defects were randomly divided into two groups: in Group C (control), the defect was filled only by a blood clot and, in Group FAT (i.e., fragmented adipose tissue), the defect was filled with fragmented autogenous adipose tissue grafts. The groups were divided into subgroups (n = 7) for euthanasia at 7, 15, and 40 days after the procedure had been conducted. Histologic and histometric analyses were performed. Data were statistically analysed with ANOVA and Tukey’s tests (p < 0.05). Results The amount of bone formation did not show statistically significant differences seven days after the operation, which indicates that the groups had similar amounts of mineral deposition in the earlier period of the repair. Conversely, a significant of amount of bone matrix deposition was identified in the FAT group at 15 and 40 days following the operation, both on the border and in the body of the defect. Such an outcome was not found in the control group. Conclusion In this study, an autologous adipose tissue graft may be considered as likely biomaterial for bone regeneration, since it positively affected the amount of bone formation in surgically created CSD in the rabbits’ calvaria 40 days after the procedure had been performed. Further investigations with a longer time evaluation are warranted to determine the effectiveness of autologous adipose tissue graft in the bone healing. Key words:Adipose tissue, bone regeneration, rabbits, critical defects.

This study analyzed the influence of fragmented autogenous white subcutaneous adipose tissue (WSAT) on bone healing in critical-size defects created in rabbit calvaria. A 15-mm diameter defect was created in the calvaria of 42 rabbits, which were treated with 86 mm3 WSAT grafts or filled only with blood clots (control). Animals were euthanized at 7, 15, and 40 days postsurgery (n = 7), and the data were analyzed using histomorphometry and immunohistochemistry using the anti-CD34 and bone morphogenetic protein-2 (BMP2) antibodies. The calvaria treated with only blood clots demonstrated positivity to CD34 concentrated in endothelial cells, whereas the BMP2 were restricted to the borders of the defects. In contrast, the group treated with WSAT revealed fatty cells exhibiting positivity to BMP2 both in membrane and cytoplasm and intense quantities of stromal spindle cells that exhibited positivity to CD34 simultaneously to BMP2; these results together coincided with a larger bone matrix deposited in all postsurgery periods analyzed. These results revealed that the WSAT may be an alternative to craniofacial bone reconstruction because the adipose tissue exhibited prominent immunoexpression of BMP2, which was coexpressed with stromal CD34+ cells, indicating the plasticity of CD34+ stem cells into osteoblasts, and in the adipocytes, facts that suggest bone tissue development through cellular transdifferentiation from adipocytes.

Objective : This study analyzed the influence of autogenous white adipose tissue on bone matrix development in critical-size defects created in rabbit calvaria. Materials and methods : A 15-mm-diameter defect was created in the calvaria of 42 rabbits. Twenty-one rabbits were treated with 86 mm(3) of immediate transplant of fragmented white subcutaneous adipose tissue (WSAT); the others constituted the control group (sham). The animals were euthanized at 7, 15, and 40 days postsurgery (n = 7), and the histological data were analyzed by histomorphometry and immunohistochemistry using the anti-adiponectin and parathyroid hormone 1-receptor (PTH1R) antibodies. Results : The calvariae treated with fragmented WSAT demonstrated significant bone formation. These results coincided with the significant presence of immunopositivity to adiponectin and PTH1R in loci, which in turn coincided with the increase in bonelike matrix deposited both in fat tissue stroma and adipocytes' cytoplasm. In contrast, the control group revealed a small amount of bone-matrix deposition and presented scarce PTH1R expression and a lack of immunostain for adiponectin. Conclusion : These results indicate that transplant of fragmented white subcutaneous adipose tissue may be an alternative to treatment of craniofacial bone deformities because adipose tissue suffers from osseous metaplasia and exhibits immunoexpression of the adiponectin and PTH1R, which are proteins associated with bone metabolism.

The proteins Wnts are considered a key regulator of the early development of the skeleton. Aim: The aim of this study was to evaluate the presence of the protein Wnt10b as a marker of bone repair in critical size defects surgically created in the calvaria of rabbits treated with fragmented autogenous adipose tissue graft. Methods: A total of 28 rabbits were divided into two groups: the Control group (C) and Adipose Tissue Graft group (ATG). A CSD measuring 15 mm in diameter was created in the calvaria of each animal. In rabbits of the C group, the defect was filled only with blood clot, and in ATG group, the defect was filled with fragmented adipose tissue graft. The two groups were divided into two subgroups (n = 7) for euthanasia 15 and 40 days after surgery. Histological and immunohistochemically analyses were performed to evaluate the neoformed bone and the presence/concentration of Wnt10b protein. The Kruskal-Wallis test was performed to compare the means and standard deviations of the number of Wnt10b + cells/mm2 in both groups in each postoperative period. It was assumed a significance level of 5%. Results: After 40 days, the mean concentration of the protein Wnt10b in ATG group was 26.26 (+-6.97) significant higher (p<0,001) than the mean in C group that was 305 (37.41). Conclusion: The protein Wnt10b would play a crucial role in the signaling of bone formation in bone defects treated with fragmented autogenous adipose tissue graft.