Adipose-Derived Stromal Cell-Sheets Sandwiched, Book-Shaped Acellular Dermal Matrix Capable of Sustained Release of Basic Fibroblast Growth Factor Promote Diabetic Wound Healing

Abstract

The management of diabetic wounds is a therapeutic challenge in clinical settings. Current tissue engineering strategies for diabetic wound healing are insufficient, owing to the lack of an appropriate scaffold that can load a large number of stem cells and induce the interaction of stem cells to form granulation tissue. Herein we fabricated a book-shaped decellularized dermal matrix (BDDM), which shows a high resemblance to native dermal tissue in terms of its histology, microstructure, and ingredients, is non-cytotoxic and low-immunogenic, and allows adipose-derived stromal cell (ASC) attachment and proliferation. Then, a collagen-binding domain (CBD) capable of binding collagen was fused into basic fibroblast growth factor (bFGF) to synthetize a recombinant growth factor (termed as CBD–bFGF). After that, CBD–bFGF was tethered onto the collagen fibers of BDDM to improve its endothelial inducibility. Finally, a functional scaffold (CBD–bFGF/BDDM) was fabricated. In vitro and in vivo experiments demonstrated that CBD–bFGF/BDDM can release tethered bFGF with a sustained release profile, steadily inducing the interaction of stem cells down to endothelial differentiation. ASCs were cultured to form a cell sheet and then sandwiched by CBD–bFGF/BDDM, thus enlarging the number of stem cells loaded into the scaffold. Using a rat model, the ASC sheets sandwiched with CBD–bFGF/BDDM (ASCs/CBD–bFGF/BDDM) were capable of enhancing the formation of granulation tissue, promoting angiogenesis, and facilitating collagen deposition and remodeling. Therefore, the findings of this study demonstrate that ASCs/CBD–bFGF/BDDM could be applicable for diabetic wound healing.

Enhanced angiogenic potential of adipose-derived stem cell sheets by integration with cell spheroids of the same source

“…Taking advantage of the enhanced gene expression of angiogenic growth factors and endothelial markers after ASC spheroid formation, the spheroid sheet composite system demonstrated enhanced expression of these angiogenesis-related factors relative to ASC sheet alone. Co-delivery with recombinant growth factors or gene transfection had been applied to circumvent this disadvantage of ASC sheet therapy previously [ 13 , 14 ]. In comparison with these maneuvers, our approach of combining ASC spheroids and sheets employed no exogenous biological or genetic material, thus significantly decreasing the regulatory hurdles for clinical translation.…”

“…Several studies have suggested that VEGF is a key regulator of the paracrine effects of ASCs [ 12 ], so decreased VEGF secretion may hinder the regenerative effects of ASC sheets for ischemic tissues. To address this shortcoming, ASC sheets were attached to FGF2-tethered decellularized dermal matrix to enhance their angiogenic potential [ 13 ]. In another study, ASC sheets were transfected to express VEGF to restore perfusion and protect ischemic tissues [ 14 ].…”

Adipose-Derived Stem Cells for the Treatment of Diabetic Wound: From Basic Study to Clinical Application

“…Diabetic ASCs treated diabetic wounds are shown to have a longer time of complete healing than healthy ASCs treated wounds, and shorter than non-treated wounds (37,48). Application of non-diabetic human-derived ASCs on diabetic rats showed the average time of wound closure and the healing area measured at the same time is significantly increased in normal ASCs treated rats than diabetic ASCs treated rats (32,33,46,49,61). Most studies evaluate the area of healing on 3, 7, 14 days after injuries.…”

“…In addition, gene-modified scaffolds may be more targeted to specific pathological conditions. The combination of ASCs and acellular dermal matrix (ADM) can also enhance wound repair in diabetic mice models, in which ADM support the proliferation and growth of ASCs ( 61 , 77 ). Besides, artificial engineered scaffolds such as gelatin gel, artificial dermis, and porous polymer ultrathin films have been studied as ASCs delivering technologies ( 78 , 79 , 81 , 82 ).…”

“…As the survival rate of ASCs is limited in traditional injection, biological scaffolds cell delivery systems provide appropriate environment for cell adhesion, proliferation, and differentiation (73,74). In recent studies, ASCs can be delivered by nanosheets, artificial gel, artificial dermis, cell matrix derived hydrogels, silk fibroin, acellular dermal matrix based and gene-activated scaffolds (49,52,61,(75)(76)(77)(78)(79)(80)(81)(82)(83). Natural scaffolds are becoming popular because of the well biocompatibility.…”