Extracellular Vesicle-functionalized Decalcified Bone Matrix Scaffolds with Enhanced Pro-angiogenic and Pro-bone Regeneration Activities

Abstract

Vascularization is crucial for bone regeneration after the transplantation of tissue-engineered bone grafts in the clinical setting. Growing evidence suggests that mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) are potently pro-angiogenic both in vitro and in vivo. In the current study, we fabricated a novel EV-functionalized scaffold with enhanced pro-angiogenic and pro-bone regeneration activities by coating decalcified bone matrix (DBM) with MSC-derived EVs. EVs were harvested from rat bone marrow-derived MSCs and the pro-angiogenic potential of EVs was investigated in vitro. DBM scaffolds were then coated with EVs, and the modification was verified by scanning electron microscopy and confocal microscopy. Next, the pro-angiogenic and pro-bone regeneration activities of EV-modified scaffolds were evaluated in a subcutaneous bone formation model in nude mice. Micro-computed tomography scanning analysis showed that EV-modified scaffolds with seeded cells enhanced bone formation. Enhanced bone formation was confirmed by histological analysis. Immunohistochemical staining for CD31 proved that EV-modified scaffolds promoted vascularization in the grafts, thereby enhancing bone regeneration. This novel scaffold modification method provides a promising way to promote vascularization, which is essential for bone tissue engineering.

Human bone marrow mesenchymal stem/stromal cell behaviour is coordinated via mechanically activated osteocyte-derived extracellular vesicles

“…Many of the proteins identified in this paper have also been identified in a proteomic analysis of osteoblast released EVs [31, 52]. A previous in vivo study has suggested a role for EVs in systemic signalling, demonstrating altered miRNA expression in EVs isolated from the plasma of osteocyte ablated mice and wild-type mice [24], while other studies have demonstrated the potential for EVs in therapeutics to enhance osteogenic gene expression [53], the use of drug loaded EVs for osteoporosis therapies [27], and the use of EVs for functionalisation of TE scaffolds to enhance bone regeneration [54, 55]. In addition to osteocyte derived MAEVs and the contents driving MSC osteogenesis, MAEVs may also act as sites for mineral nucleation, as has previously been demonstrated in osteoblast EVs [56, 57].…”

An in vivo comparative study of the gelatin microtissue‐based bottom‐up strategy and top‐down strategy in bone tissue engineering application

“…For each section, three images were captured for quantitative analysis of the positive staining of CD31. Image‐Pro Plus 6.0 software was used to evaluate the mean vessel density with the calculation of positively stained vessel area per unit area …”

“…Image-Pro Plus 6.0 software was used to evaluate the mean vessel density with the calculation of positively stained vessel area per unit area. 24…”

Engineering Extracellular Vesicles as Nanotherapeutics for Regenerative Medicine

“…To date, MSC-derived EVs have been widely used to functionalize a variety of scaffold structures due to their proangiogenic properties. Xie et al coated decalcified bone matrix (DBM) with bone marrow-derived MSC EVs using fibronectin as the immobilizing agent [54].…”