Mineral deposition and vascular invasion of hydroxyapatite reinforced collagen scaffolds seeded with human adipose-derived stem cells

Abstract

Background Collagen-based scaffolds reinforced with hydroxyapatite (HA) are an attractive choice for bone tissue engineering because their composition mimics that of bone. We previously reported the development of compression-molded collagen-HA scaffolds that exhibited high porosity, interconnected pores, and mechanical properties that were well-suited for surgical handling and fixation. The objective of this study was to investigate these novel collagen-HA scaffolds in combination with human adipose-derived stem cells (hASCs) as a template for bone formation in a subcutaneous athymic mouse model. Methods Collagen-HA scaffolds and collagen-only scaffolds were fabricated as previously described, and a clinically approved bone void filler was used as a control for the material. Constructs were seeded with hASCs and were pre-treated with either control or osteogenic media. A cell-free group was also included. Scaffolds were implanted subcutaneously in the backs of athymic nude mice for 8 weeks. Mineral deposition was quantified via micro-computed tomography. Histological and immunofluorescence images of the explants were used to analyze their vascular invasion, remodeling and cellularity. Results Cell-free collagen-HA scaffolds and those that were pre-seeded with osteogenically differentiated hASCs supported mineral deposition and vascular invasion at comparable rates, while cell-seeded constructs treated with the control medium showed lower mineralization after implantation. HA-reinforcement allowed collagen constructs to maintain their shape, provided improved cell-tissue-scaffold integration, and resulted in a more organized tissue when pre-treated in an osteogenic medium. Scaffold type and pre-treatment also determined osteoclast activity and therefore potential remodeling of the constructs. Conclusions The results of this study cumulatively indicate that treatment medium and scaffold composition direct mineralization and angiogenic tissue formation in an ectopic model. The data suggest that it may be necessary to match the scaffold with a particular cell type and cell-specific pre-treatment to achieve optimal bone formation.

Enhanced Osteogenic Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells by a Hybrid Hydroxylapatite/Collagen Scaffold

“…Many efforts have been carried out to develop innovative laboratory-produced tissue replacements. However, current approaches to bone tissue engineering usually lack sufficient functionality respect to native bone matrix ( Sheehy et al, 2019 ; Weiss-Bilka et al, 2019 ).…”

“…Type I Col is the main molecule of interest when it comes to bone regeneration, as it is abundantly found in bone ( Sherman et al, 2015 ). Thus, biocomposite scaffolds composed of Col reinforced with HA are an attractive choice for bone tissue engineering since their composition mimics bone ( Weiss-Bilka et al, 2019 ). Hybrid HA/Col scaffold, composed of Granular Pro Osteon ® 200 coralline HA and Avitene TM Microfibrillar Collagen Hemostat (Coll/Pro Osteon ® 200), is used during malarplasty in maxilla-facial patients, producing a successful outcome and promoting bone formation ( D’Agostino et al, 2016 ; Mazzoni et al, 2020 ).…”

Mimicking the Hierarchical Organization of Natural Collagen: Toward the Development of Ideal Scaffolding Material for Tissue Regeneration

“…Mineralized collagen scaffolds own better mechanical properties and osteoconductivity and exhibit higher levels of osteogenic gene expression than unmineralized ones ( Liu et al, 2011 ). In this regard, extensive research has been conducted on the fabrication of both intrafibrillar and extrafibrillar mineralized collagen scaffolds from nanoscale to macroscale to promote bone repair, demonstrating solid advantages in intrafibrillar mineralized collagen fibrils ( Weisgerber et al, 2015 ; Weiss-Bilka et al, 2019 ; Yu et al, 2020 ). Due to exceptional outcomes, currently, several collagen-mineral scaffolds are approved and commercially available, such as Collagraft TM (Collagen Corp., United States) ( Leupold et al, 2006 ), OssiMend TM Bone Graft Matrix (Collagen Matrix Inc., United States) ( Ferreira et al, 2021 ), and Healos (DePuy Spine, United States) ( Carter et al, 2009 ; Kunakornsawat et al, 2013 ).…”

Osteogenic effects of exosomes derived from human chorion membrane extracts

“…Osteogenesis is a multistep process, and can be divided into early, middle, and late stages [ 16 , 17 ]. Treatment of MG63 cells with CME-Exo induced osteogenesis, ALP activity was critically increased from 3 to 7 days in the early stage of osteogenesis, and the mineral deposition was observed from 14 to 20 days in the late stage of osteogenesis [ 14 , 18 ]. Therefore, we investigated the ALP activity and mineralization of CME-Exo-treated MG63 cells during osteogenesis in vitro.…”