In vivo evaluation of MMP sensitive high‐molecular weight HA‐based hydrogels for bone tissue engineering

Abstract

Hyaluronic acid (170 kDa)-based hydrogel was synthesized using acrylated hyaluronic acid (HA) and matrix metalloproteinase (MMP) sensitive HA-based hydrogels were then prepared by conjugation with two different peptides: cell adhesion peptides containing integrin-binding domains (Arg-Gly-Asp: RGD) and a cross-linker with MMP degradable peptides to mimic the remodeling characteristics of natural extracellular matrices by cell-derived MMPs. Mechanical properties of these hydrogels were evaluated with different weight percentages (2.5 and 3.5 wt %) by measuring elastic modulus, viscous modulus, and swelling ratio. Human mesenchymal stem cells (hMSCs) were then cultured in MMP-sensitive or insensitive HA-based hydrogels and/or immobilized cell adhesive RGD peptides in vitro. Actin staining and image analysis proved that cells cultured in the MMP-sensitive hydrogel with RGD peptides showed extensive cell spreading and sprouting. Gene expression analysis showed that bone specific genes such as alkaline phosphatase, osteocalcin, and osteopontin increased in MMP-sensitive hydrogels as biomolecules such as BMPs and cells were added in the gels. For in vivo calvarial defect regeneration, five different samples (MMP insensitive hydrogel, MMP sensitive hydrogel, MMP sensitive hydrogel with BMP-2, MMP sensitive hydrogel with hMSC, and MMP sensitive hydrogel with BMP-2 and hMSC) were prepared. After 4 weeks of implantation, the Masson-Trichrome staining and micro computed tomography scan results demonstrated that the MMP sensitive hydrogels with BMP-2 and hMSCs have the highest mature bone formation. The MMP sensitive HA-based hydrogel could become useful scaffolds in bone tissue engineering with improvements on tissue remodeling rates and regeneration activity.

Bone Regeneration by Transplantation of Human Mesenchymal Stromal Cells in a Rabbit Mandibular Distraction Osteogenesis Model

“…On the contrary, there is also abundant evidence based on animal studies that ex vivoexpanded hMSCs improve injury repair in a range of tissue, including bone or neuron, after in vivo transplantation into animals without any notable inflammation. [9][10][11] Consistently, our previous studies have shown enhanced bone regeneration in a rat calvarial defect model using BM-hMSCs delivered by a hydrogel carrier. 10,11 There is no doubt that for direct orthotopic applications, it would be helpful to use appropriate scaffolds to hold cells in place and support their differentiation.…”

“…[9][10][11] Consistently, our previous studies have shown enhanced bone regeneration in a rat calvarial defect model using BM-hMSCs delivered by a hydrogel carrier. 10,11 There is no doubt that for direct orthotopic applications, it would be helpful to use appropriate scaffolds to hold cells in place and support their differentiation. 7 However, in DO studies, MSCs have been delivered using direct injection either with an injectable gel 15 or recently by suspension in a saline solution 17,29 into the osteotomy site, probably due to the anatomical and pathological characteristics of DO.…”

“…In contrary to expectations, there is abundant evidence based on animal studies that ex vivo expanded hMSCs improve tissue regeneration and wound healing after in vivo transplantation into animals without notable immunological rejection. [9][10][11] However, the mechanism by which hMSCs promote tissue regeneration remains unclear, as it is very rare for injected hMSCs to differentiate into cells of the target tissue. 2,12 Distraction osteogenesis (DO) is a unique model to regenerate bone that involves coupling of mechanical strain and bone cells in vivo.…”

In VivoGene Activity of Human Mesenchymal Stem Cells After Scaffold-Mediated Local Transplantation

“…Numerous studies have shown that codelivery of growth factors and MSCs both in vitro and in vivo enables regenerative potential more efficiently than MSCs alone. 6,21,22 When cotransplanted with MSCs and growth factors, a collagen sponge is preferred. This is especially the case when BMP-2 is used as a growth factor; collagen sponges have characteristics that allow for sustained release of BMP-2 in addition to their biocompatible, osteoconductive properties.…”

Role of Mesenchymal Stem Cells in Bone Regenerative Medicine: What Is the Evidence?

“…The incorporation of growth-promotive factors is used to stimulate the differentiation of transplanted MSCs and enhance their activity as well as recruit undifferentiated osteoprogenitor cells into the vehicle. Until now, numerous investigations have shown the regenerative potential of growth factors and MSC codelivery in vitro and in vivo [Kim et al, 2007[Kim et al, , 2010Terella et al, 2010]; however, the synergistic effect of growth factors for a significant increase in bone formation is still unclear. Codelivery of MSCs with other cell types, such as endothelial cells and osteoblasts, may be another interesting option for increasing the osteogenic efficacy.…”