<p>Delivery vehicle of muscle-derived irisin based on silk/calcium silicate/sodium alginate composite scaffold for bone regeneration</p>

Abstract

Background: Irisin is a cytokine produced by skeletal muscle and usually plays a pivotal role in inducing fat browning and regulating energy expenditure. In recent years, it was found that irisin might be the molecular entity responsible for muscle-bone connectivity and is useful in osteogenesis induction. Materials and methods: To study its effect on bone regeneration, we developed silk/calcium silicate/sodium alginate (SCS) composite scaffold based on an interpenetrating network hydrogel containing silk fibroin, calcium silicate, sodium alginate. Then we loaded irisin on the SCS before coating it with polyvinyl alcohol (PVA). The SCS/P scaffold was physically characterized and some in vitro and in vivo experiments were carried out to evaluate the scaffold effect on bone regeneration. Results: The SCS/P scaffold was showed a porous sponge structure pursuant to scanning electron microscopy analysis. The release kinetics assay demonstrated that irisin was stably released from the irisin-loaded hybrid system (i/SCS/P system) to 50% within 7 days. Moreover, osteoinductive studies using bone marrow stem cells (BMSCs) in vitro exhibited the i/ SCS/P system improved the activity of alkaline phosphatase (ALP) and enhanced the expression levels of a series of osteogenic markers containing Runx-2, ALP, BMP2, Osterix, OCN, and OPN. Alizarin red staining also demonstrated the promotion of osteogenesis induced by i/SCS/P scaffolds. In addition, in vivo studies showed that increased bone regeneration with better mineralization and higher quality was found during the repair of rat calvarial defects through utilizing the i/SCS/P system. Conclusion: These data provided strong evidence that the composite i/SCS/P would be a promising substitute for bone tissue engineering.

Strategies for Bone Regeneration: From Graft to Tissue Engineering

“…Even if PDGF and VEGF did not affect the bone mineralization, they increased the vascularity, an essential event for tissue regeneration [ 142 ]. Many other molecules have been studied in order to promote the osteointegration and osteogenesis of scaffolds, such as irisin [ 143 ] and platelet gel [ 144 ].…”

Concentrated Conditioned Medium-Loaded Silk Nanofiber Hydrogels with Sustained Release of Bioactive Factors To Improve Skin Regeneration

“…Additionally, the results of AFM and Raman analysis proved that CCM is successfully loaded onto nanofibers. Several refers have supported strong interactions of silk and proteins. − The release behaviors of various molecules were further regulated by nanofiber and CCM concentrations, providing the possibility of revealing the underlying rules of different proteins.…”

On the road to smart biomaterials for bone research: definitions, concepts, advances, and outlook

“…94 As a potential molecule for promoting bone regeneration, specifically for enhancing muscle-bone connectivity, Irisin, a skeletal muscle-derived cytokine, loaded into silk/calcium silicate/sodium alginate composite hydrogels, upregulated the expression of several osteogenic markers containing RUNX2, ALP, BMP2, Osterix, OCN, and OPN in cultured BMSCs and improved the repair of calvarial defects in a rat model in vivo. 95 Sinapic acid is a plantderived phenolic compound with potentially beneficial effects for bone regeneration. Electrospun polycaprolactone (PCL) fibrous scaffolds, containing chitosan nanoparticles loaded with sinapic acid, promoted osteoblast differentiation in vitro and accelerated bone regeneration in vivo.…”