Comparing the Osteogenic Potential and Bone Regeneration Capacities of Dedifferentiated Fat Cells and Adipose-Derived Stem Cells In Vitro and In Vivo: Application of DFAT Cells Isolated by a Mesh Method

Background: We investigated and compared the osteogenic potential and bone regeneration capacities of dedifferentiated fat cells (DFAT cells) and adipose-derived stem cells (ASCs). Method: We isolated DFAT cells and ASCs from GFP mice. DFAT cells were established by a new culture method using a mesh culture instead of a ceiling culture. The isolated DFAT cells and ASCs were incubated in osteogenic medium, then alizarin red staining, alkaline phosphatase (ALP) assays, and RT-PCR (for RUNX2, osteopontin, DLX5, osterix, and osteocalcin) were performed to evaluate the osteoblastic differentiation ability of both cell types in vitro. In vivo, the DFAT cells and ASCs were incubated in osteogenic medium for four weeks and seeded on collagen composite scaffolds, then implanted subcutaneously into the backs of mice. We then performed hematoxylin and eosin staining and immunostaining for GFP and osteocalcin. Results: The alizarin red-stained areas in DFAT cells showed weak calcification ability at two weeks, but high calcification ability at three weeks, similar to ASCs. The ALP levels of ASCs increased earlier than in DFAT cells and showed a significant difference (p < 0.05) at 6 and 9 days. The ALP levels of DFATs were higher than those of ASCs after 12 days. The expression levels of osteoblast marker genes (osterix and osteocalcin) of DFAT cells and ASCs were higher after osteogenic differentiation culture. Conclusion: DFAT cells are easily isolated from a small amount of adipose tissue and are readily expanded with high purity; thus, DFAT cells are applicable to many tissue-engineering strategies and cell-based therapies.

Comparison of Allogenic and Autogenic Implantations of Dedifferentiated Fat Cells On Monoclonal Antibody 1-22-3-Induced Glomerulonephritis in Rats

Background We established an adipogenic progenitor cell line derived from mature adipocytes and named these cells dedifferentiated fat (DFAT) cells, which have been shown to have characteristics very similar to those of mesenchymal stem cells (MSCs). The potential application of DFAT cells to support cell-based therapies for regenerative and immunosuppressive therapies has been suggested. The present study was designed to address beneficial ways that DFAT implantation can be used clinically as immunosuppressive therapy to treat immunological glomerulonephritis. Methods We evaluated distribution of DFAT cells after intravenous injection through the tail vein in Wistar rats. We examined effects of allogenic implantation of DFAT cells on BrdU incorporation into kidney from rats with monoclonal antibody (mAb) 1-22-3-induced glomerulonephritis. We compared effects of allogenic and autogenic implantations of DFAT cells on excretion of urinary protein, renal function, and glomerular and nephrotubular injuries in these rats, and serum levels of tumor necrosis factor-stimulated gene-6 (TSG-6), and expression of TSG-6 mRNA in kidney. Results The allogenic implantations of DFAT cells trapped in lung improved excretion of urinary protein and renal function, and significantly suppressed glomerular and nephrotubular injuries in the rats with mAb1-22-3-induced glomerulonephritis compared with the autogenic implantations. The allogenic implantation of DFAT cells increased serum levels of TSG-6 especially in mAb 1-22-3-induced glomerulonephritis and significantly increased the expression of TSG-6 mRNA in kidney compared to the autogenic implantation. Conclusion These findings suggest that allogenic implantation of DFAT cells could be clinically useful immunosuppressive therapy for immunological glomerulonephritis.

Effects of Dedifferentiated Fat Cells on Neurogenic Differentiation and Cell Proliferation in Neuroblastoma Cells

Recent reports demonstrated that mesenchymal stem cells (MSCs) can induce differentiation of neuroblastoma (NB) cells. Dedifferentiated fat cells (DFAT) and MSCs have similar properties. The present study investigated whether DFAT can induce NB cell differentiation and suppress cell proliferation. DFAT was obtained from mature adipocytes isolated from adipose tissue from a ceiling culture. NB cells were cultured in a medium with/without DFAT, and subsequently in a DFAT-conditioned medium (CM) with/without phosphatidylinositol 3 kinase (PI3K) inhibitor. Length of neurites was measured, and the mRNA expression levels of the neurofilament (NF) and tubulin beta III (TUBβ3) were assessed using quantitative real-time reverse transcription polymerase chain reaction. Cell viability was assessed by the water-soluble tetrazolium salt-1 assay. NB cells cultured with DFAT elongated the neurites and upregulated the expression of NF and Tubβ3 compared with the control. However, NB cells cultured in DFAT-CM demonstrated increased cell viability compared with the control. NB cells cultured with DFAT-CM and PI3K inhibitor suppressed cell viability and demonstrated increased neurite length and expression and upregulation of Tubβ3. Therefore, the combined use of DFAT-CM and PI3K inhibitors suppresses the proliferation of NB cells and induces their differentiation. DFAT may offer new insights into therapeutic approaches in NB.

Neurogenic and Neuroprotective Potential of Stem/Stromal Cells Derived from Adipose Tissue

Currently, the number of stem-cell based experimental therapies in neurological injuries and neurodegenerative disorders has been massively increasing. Despite the fact that we still have not obtained strong evidence of mesenchymal stem/stromal cells’ neurogenic effectiveness in vivo, research may need to focus on more appropriate sources that result in more therapeutically promising cell populations. In this study, we used dedifferentiated fat cells (DFAT) that are proven to demonstrate more pluripotent abilities in comparison with standard adipose stromal cells (ASCs). We used the ceiling culture method to establish DFAT cells and to optimize culture conditions with the use of a physioxic environment (5% O2). We also performed neural differentiation tests and assessed the neurogenic and neuroprotective capability of both DFAT cells and ASCs. Our results show that DFAT cells may have a better ability to differentiate into oligodendrocytes, astrocytes, and neuron-like cells, both in culture supplemented with N21 and in co-culture with oxygen–glucose-deprived (OGD) hippocampal organotypic slice culture (OHC) in comparison with ASCs. Results also show that DFAT cells have a different secretory profile than ASCs after contact with injured tissue. In conclusion, DFAT cells constitute a distinct subpopulation and may be an alternative source in cell therapy for the treatment of nervous system disorders.