Decellularized adipose tissue: A key factor in promoting fat regeneration by recruiting and inducing mesenchymal stem cells.

Background: Decellularized adipose tissue (DAT) has attracted much attention due to its wide range of sources and adipose regeneration capacity. However, the lipogenic efficiency of DAT is still controversial due to its unclear mechanism. To this point, it is crucial to clarify the mechanism of DAT in promoting adipose regeneration Objective: This study aims to explore the mechanism of DAT promoting adipose regeneration and survival mechanism of DAT transplantation in vivo.

Methods: DAT preparation by repeated freeze-thaw, enzymatic digestion, and isopropanol degreasing. Histology, DAPI, immunohistochemistry, immunofluorescence and scanning electron microscopy confirmed the efficacy and reproducibility of these approaches. BM-MSCs, ADSCs and UCMSCs were cocultured with DAT for 14 days and then stained with oil red O. Adipogenic genes of three MSCs were detected by RT-PCR. DAT and adipose tissue were transplanted subcutaneously into the back of nude mice to observe medium and long-term morphological changes, vascularization, and lipid-forming efficiency. Mass spectrometry (MS)-based proteomic to analyze the adipogenic protein contents of DAT and adipose tissue.

Results: The DAT without any cellular components but with an abundance of collagen; neither DNA nor lipids were detected. Seeding experiments with MSCs indicated that the DAT provided an inductive microenvironment for adipogenesis, supporting the expression of the master regulators PPARγ. Within four months after transplantation, HE morphology of DAT was identical to adipose cells. Immunofluorescence markers CD31 and perilipin were increased in DAT, while the retention rate gradually decreased over time, eventually accounting for 33.7% of the original volume. MS-based proteomic analyses identified 1013 types of proteins in adipose tissue and 29 proteins in the DAT. Analyses of GO and KEGG databases suggested that DAT contained a variety of proteins involved in fat metabolism.

Conclusions: DAT can interact with different types of MSCs and ultimately achieve adipose regeneration. The presence of multiple adipogenic proteins in DAT make it play a vital role in adipose regeneration. DAT is expected to be an ideal bio-derived scaffold for adipose tissue engineering.