Optimization of photocrosslinked gelatin/hyaluronic acid hybrid scaffold for the repair of cartilage defect

Abstract

Summary There is no therapy currently available for fully repair of articular cartilage lesion. Our laboratory has recently developed a visible light-activatable methacrylated gelatin (mGL) hydrogel with the potential for cartilage regeneration. In this study, we further optimized mGL scaffolds by supplementing methacrylated hyaluronic acid (mHA), which has been shown to stimulate chondrogenesis via activation of critical cellular signaling pathways. We hypothesized that the introduction of an optimal ratio of mHA would enhance the biological properties of mGL scaffolds and augment chondrogenesis of human bone marrow-derived mesenchymal stem cells (hBMSCs). To test this hypothesis, hybrid scaffolds consisting of mGL and mHA at different weight ratios were fabricated with hBMSCs encapsulated at 20×106 cells/mL and maintained in a chondrogenesis-promoting medium. The chondrogenenic differentiation of hBMSCs within different scaffolds was estimated after 8 weeks of culture. Our results showed that mGL/mHA at a 9:1 (%, w/v) ratio resulted in the lowest hBMSC hypertrophy and highest glycosaminoglycan production, with slightly increased volume of the entire construct. The applicability of this optimally designed mGL/mHA hybrid scaffold for cartilage repair was then examined in vivo. A full-thickness cylindrical osteochondral defect was surgically created in the rabbit femoral condyle and a 3-dimensional cell-biomaterial construct was fabricated by in situ photo-crosslinking to fully fill the lesion site. The results showed that implantation of the mGL/mHA (9:1) construct resulted in both cartilage and subchondral bone regeneration after 12 weeks, supporting its use as a promising scaffold for repair and resurfacing of articular cartilage defects in the clinical setting.

Biomimetic Cell-Laden MeHA Hydrogels for the Regeneration of Cartilage Tissue

“…As expected, the softer CS-MeHA hydrogel exhibited a higher degree of swelling and degradation rate compared to the more rigid MeHA hydrogel ( Figure 4 b,c) due to the lower degree of crosslinking of CS-MeHA polymer chains (i.e., the presence of CS pending peptides). It should be noted that, to date, the optimal swelling ratio that could ensure the best clinical results has not been defined [ 47 ]. Regarding hydrogel degradation, since the thiol-methacrylate ester bond is not prone to hydrolysis [ 48 ], MeHA and CS-MeHA hydrogel degradation by the recombinant MMP7 enzyme was attributed to the cleavage of the MMP7-sensitive peptide crosslinker [ 15 , 19 ].…”

Glycosaminoglycans in Tissue Engineering: A Review

“…Gelatin is an ideal copolymer for HA as it provides structural support and RGD-integrin binding sites that allow cell adhesion and proliferation, unlike HA alone [ 32 ]. Gelatin-HA constructs have been studied extensively for regeneration of articular cartilage [ 33 , 34 , 35 ], wound healing [ 36 , 37 , 38 ], and even vocal fold repair [ 39 ] due to their chondrogenic, angiogenic, and cell adhesive properties, and their tunable viscoelastic properties. Like HA, gelatin can be methacrylated, which allows for photopolymerization of gelatin-gelatin or gelatin-HA crosslinks.…”

“…Like HA, gelatin can be methacrylated, which allows for photopolymerization of gelatin-gelatin or gelatin-HA crosslinks. Constructs made of methacrylated gelatin and HA have been shown to suppress hypertrophy and increase GAG expression by embedded, human bone marrow stem cells and, when tested in a full thickness osteochondral defect in rabbits, showed good cartilage regeneration [ 33 ]. Methacrylated HA and methacrylated gelatin can also be 3D bio-printed and polymerized with embedded cells without affecting their viability or chondrogenic properties, making them a good platform for custom, patient-specific cartilage implants [ 35 ].…”

Translational applications of photopolymerizable hydrogels for cartilage repair

“…The methods of photopolymerization were based on the use of physical crosslinks, with UV light applied in 17 studies (Bryant & Anseth, 2001; Bryant & Anseth, 2002; Bryant & Anseth, 2003; Buxton et al, 2007; Dua et al, 2016; Elisseeff et al, 2000; Hayami et al, 2016; Lee et al, 2006; Levett et al, 2014; Lin et al, 2017; Neumann et al, 2016; Ramaswamy et al, 2008a; Ramaswamy et al, 2008b; Roberts et al, 2011; Roberts & Bryant, 2013; Sharma et al, 2007; Williams et al, 2003) and VL in 6 studies (Hoshikawa et al, 2006; Kim et al, 2015; Lin et al, 2014; Lin et al, 2019; Pascual-Garrido et al, 2019; Werkmeister et al, 2010). Both synthetic (Bryant & Anseth, 2001; Bryant & Anseth, 2002; Bryant & Anseth, 2003; Buxton et al, 2007; Elisseeff et al, 2000; Hoshikawa et al, 2006; Lin et al, 2014; Neumann et al, 2016; Ramaswamy et al, 2008a; Roberts & Bryant, 2013; Williams et al, 2003) and hybrid photopolymerizable hydrogels (Dua et al, 2016; Hayami et al, 2016; Kim et al, 2015; Lee et al, 2006; Levett et al, 2014; Lin et al, 2017; Lin et al, 2019; Pascual-Garrido et al, 2019; Ramaswamy et al, 2008b; Roberts et al, 2011; Sharma et al, 2007; Werkmeister et al, 2010) have been employed and their use and application are described below.

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“…Lin et al (Lin et al, 2017) described synergistic effects of chondrogenic preconditioning and mechanical stimulation on bone marrow-derived MSCs in methacrylated HA (MeHA) hydrogels, with superior chondrogenic differentiation in rat osteochondral defects. Lin et al (Lin et al, 2019) reported that methacrylated gelatin (mGL)/MHA enhanced the regeneration of the osteochondral unit in rabbit full-thickness osteochondral defects. Pascual-Garrido et al ( Pascual-Garrido et al, 2019 ) noted that MSCs undergo effective chondrogenesis in a cartilage-mimetic hydrogel using PEG with matrix metalloproteinase 2 (PEG/MMP-2) that can be delivered in vivo and photopolymerized intra-operatively in situ.…”