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

https://doi.org/10.1016/j.bbrc.2020.12.108Get rights and content

Highlights

  • We determined that the outcome of DAT after transplantation was adipose tissue. After transplantation in vivo, DAT can still survive in animals even after a long period of time.

We clarify the mechanism of DAT in promoting adipose regeneration.

  • We figure out the differences in the protein composition of DAT and adipose tissue through MS-based proteomic, and discovered some proteins that promote fat regeneration from adipose tissue and DAT species.

  • Through the protein composition of DAT and its special spatial structure, 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.

Abstract

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.

Introduction

Autologous adipose tissue is considered as an ideal graft due to advantages of its availability, no foreign body reaction, soft touch [[1], [2], [3]]. However, the actual mechanism on how fat graft survives remains less completely understood [4,5]. “Cell survival theory” proposed that the mechanism of fat graft survival is based on established early blood circulation through anastomosis of the fat graft and host blood vessels [6]. The fate of adipocytes after nonvascularized fat grafting has been widely confirmed by “host replacement theory”. Host replacement theory clarified that under severe ischemia, all adipocytes underwent degenerative changes and subsequent adaptive tissue remodeling. Adipocytes within the fat pad die easily under ischemic conditions, whereas adiposederived stem or progenitor cells could survive under ischemic conditions and were activated and contributed to adipose tissue repair later on [[7], [8], [9]]– (see Table 1)

DAT has attracted much attention due to its wide range of sources and good regeneration capacity. Previous study emphasize the importance of the ECM in mediating ADSCs adipogenesis and point to the potential of the DAT microcarriers for use in soft tissue regeneration, including applications in plastic and reconstructive surgery [10]. Studies had also shown that DAT may displayed the capacity to promote in vivo adipose depot formation through the recruitment of host progenitor cells and vasculature [11,12]. However, it is unclear whether the DAT plays a positive role in the adipogenesis of other mesenchymal stem cells. The long-term transplantation efficiency and denouement of DAT is also unclear. Overall, to clarify its mechanism of promoting fat formation is beneficial to improve the adipose regeneration efficiency of DAT.

Section snippets

Source of specimens

Human adipose tissue was obtained from healthy patients (19–45 years of age) undergoing autologous fat transplantation surgery. Experimental umbilical cords (UCs) were obtained from healthy mothers who underwent cesarean section at term. Informed consent was obtained from all participants. This study was approved by the Medical Ethics Committees of the First Affiliated Hospital of Jinan University.

Animals

Adult male Sprague Dawley (SD) rats (Guangdong Medical Laboratory Animal Center) that were 8–10

General observations

As shown in Fig. 1, after decellularization of the adipose tissue, the original tissue shape was largely retained, and the tissue was milky white or light yellow and ductile. After lyophilization, the tissue was a porous foam.

Gross observation after transplantation

After transplantation, the color of DAT gradually turned yellowish, and the texture of DAT was obviously softened, and the border was rounded, with the original fiber and foam structure completely invisible. DAT gradually converted into adipose tissue. Additionally, the

Discussion

In the present study, the overall process involves repeated freezing and thawing for physical disruption [20,21]. After completion of the decellularization step, the tissues were irradiated with 60Co γ-rays for 48 h. This step promotes cross-linking [22]. The fat obtained by our group is particulate fat extracted from the human body through the classical Coleman fat [23] transplantation procedure.

DAT have been investigated as carriers for the expansion and delivery of ADSCs for use in an array

Conclusions

In vitro experiments showed that the DAT can interact with more types of MSCs than other scaffolds and ultimately achieve adipose tissue regeneration. Through the growth factors present in the matrix and its unique spatial structure, this biological scaffold promoted adipogenic differentiation in three types of MSCs. In in vivo experiments, we successfully generated adipose tissue after DAT transplantation. Further, transplanted DAT can survive in animals even after a long period of time (16w).

Declaration of competing interest

We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled.

Acknowledgments

This work was supported by the National Nature and Science Foundation, P.R. China (No.81372065, 81871563).

References (44)

  • M. Bircoll

    Clinical analyses of clustered microcalcifications after autologous fat injection for breast augmentation

    Plast. Reconstr. Surg.

    (2011)
  • P. Tonnard et al.

    Nanofat grafting:basic research and clinical applications

    Plast. Reconstr. Surg.

    (2013)
  • M. Sun et al.

    Adipose extracellular matrix/stromal vascular fraction gel secretes angiogenic factors and enhances skin wound healing in a murine model

    BioMed Res. Int.

    (2017)
  • L.A. Peer

    Loss of weight and volume in human fat grafts with postulation of a “Cell Survival Theory”

    Plast. Reconstr. Surg.

    (1950)
  • H. Suga et al.

    Adipose tissue remodeling under ischemic: death of adipocytes and activation of stem/progenitor cells

    Plast. Reconstr. Surg.

    (2010)
  • K. Yoshimura et al.

    Cell -assisted lipotransfer (CAL) for cosmetic breast augmentation: supportive use of adiposederived stem/stromal cell

    Aesthetic Plast. Surg.

    (2008)
  • P.A. Zuk et al.

    Multilineage cells from human adipose tissue: implications for cell-based therapies

    Tissue Eng.

    (2001)
  • A. Divoux et al.

    Architecture and the extracellular matrix: the still unappreciated components of the adipose tissue

    Obes. Rev.

    (2011)
  • L.E. Flynn

    The use of decellularized adipose tissue to provide an inductive microenvironment for the adipogenic differentiation of human adiposederived stem cells

    Biomaterials

    (2010)
  • X. Liao et al.

    Preconditioning with low-level laser irradiation enhances the therapeutic potential of human adipose-derived stem cells in a mouse model of photoaged skin

    Photochem. Photobiol.

    (2018)
  • X. Jiang et al.

    A novel role of angiotensin II in epidermal cell lineage determination: angiotensin II promotes the differentiation of mesenchymal stem cells into keratinocytes through the p38 MAPK, JNK and JAK2 signalling pathways

    Exp. Dermatol.

    (2019)
  • T. de Mayo et al.

    The role of bone marrow mesenchymal stromal cell derivatives in skin wound healing in diabetic mice

    PLoS One

    (2017)
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