Project description:Articular cartilage lesions are a particular challenge for regenerative medicine due to cartilage low self-ability repair in case of damage. Hence, a significant goal of musculoskeletal tissue engineering is the development of suitable structures in virtue of their matrix composition and biomechanical properties. The objective of our study was to design in vitro a supporting structure for autologous chondrocyte growth. We realized a biohybrid composite scaffold combining a novel and nonspecific extracellular matrix (ECM), which is decellularized Wharton's jelly ECM, with the biomechanical properties of the synthetic hydrogel polyvinyl alcohol (PVA). Wharton's jelly ECM was tested for its ability in promoting scaffold colonization by chondrocytes and compared with polyvinyl alcohol itself and the more specific decellularized cartilage matrix. Our preliminary evidences highlighted the chance of using Wharton's jelly ECM in combination with PVA hydrogels as an innovative and easily available scaffold for cartilage restoration.
Project description:Articular cartilage defects fail to heal spontaneously, typically progressing to osteoarthritis. Bone marrow stimulation techniques such as microfracture (MFX) are the current surgical standard of care; however MFX typically produces an inferior fibro-cartilaginous tissue which provides only temporary symptomatic relief. Here we implanted solubilised articular cartilage extracellular matrix (ECM) derived scaffolds into critically sized chondral defects in goats, securely anchoring these implants to the joint surface using a 3D-printed fixation device that overcame the need for sutures or glues. In vitro these ECM scaffolds were found to be inherently chondro-inductive, while in vivo they promoted superior articular cartilage regeneration compared to microfracture. In an attempt to further improve the quality of repair, we loaded these scaffolds with a known chemotactic factor, transforming growth factor (TGF)-β3. In vivo such TGF-β3 loaded scaffolds promoted superior articular cartilage regeneration. This study demonstrates that ECM derived biomaterials, either alone and particularly when combined with exogenous growth factors, can successfully treat articular cartilage defects in a clinically relevant large animal model.
Project description:The cartilage lesion resulting from osteoarthritis (OA) always extends into subchondral bone. It is of great importance for simultaneous regeneration of two tissues of cartilage and subchondral bone. 3D-printed Sr5(PO4)2SiO4 (SPS) bioactive ceramic scaffolds may achieve the aim of regenerating both of cartilage and subchondral bone. We hypothesized that strontium (Sr) and silicon (Si) ions released from SPS scaffolds play a crucial role in osteochondral defect reconstruction. Methods: SPS bioactive ceramic scaffolds were fabricated by a 3D-printing method. The SEM and ICPAES were used to investigate the physicochemical properties of SPS scaffolds. The proliferation and maturation of rabbit chondrocytes stimulated by SPS bioactive ceramics were measured in vitro. The stimulatory effect of SPS scaffolds for cartilage and subchondral bone regeneration was investigated in vivo. Results: SPS scaffolds significantly stimulated chondrocyte proliferation, and SPS extracts distinctly enhanced the maturation of chondrocytes and preserved chondrocytes from OA. SPS scaffolds markedly promoted the regeneration of osteochondral defects. The complex interface microstructure between cartilage and subchondral bone was obviously reconstructed. The underlying mechanism may be related to Sr and Si ions stimulating cartilage regeneration by activating HIF pathway and promoting subchondral bone reconstruction through activating Wnt pathway, as well as preserving chondrocytes from OA via inducing autophagy and inhibiting hedgehog pathway. Conclusion: Our findings suggest that SPS scaffolds can help osteochondral defect reconstruction and well reconstruct the complex interface between cartilage and subchondral bone, which represents a promising strategy for osteochondral defect regeneration.
Project description:Transforming growth factor-β1 (TGF-β1) is essential for cartilage regeneration, but its susceptibility to enzymatic denaturation and high cost limit its application. Herein, we report Ac-LIANAKGFEFEFKFK-NH2 (LKP), a self-assembled peptide nanofiber hydrogel that can mimic the function of TGF-β1. The LKP hydrogel is simple to synthesize, and in vitro experiments confirmed its good biocompatibility and cartilage-promoting ability. However, LKP hydrogels suffer from poor mechanical properties and are prone to fragmentation; therefore, we prepared a series of injectable hydrogel composite scaffolds (SF-GMA/LKP) by combining LKP with glycidyl methacrylate (GMA)-modified silk fibroin (SF). SF-GMA/LKP composite scaffolds instantaneously induced in-situ filling of cartilage defects and, at the same time, relied on the interaction between LKP and SF-GMA interaction to prolong the duration of action of LKP. The SF-GMA/LKP10 and SF-GMA/LKP20 composite scaffolds had the best effect on neocartilage and subchondral bone reconstruction. This composite hydrogel scaffold can be used for high-quality cartilage repair.
Project description:Due to the sophisticated hierarchical structure and limited reparability of articular cartilage (AC), the ideal regeneration of AC defects has been a major challenge in the field of regenerative medicine. As defects progress, they often extend from the cartilage layer to the subchondral bone and ultimately lead to osteoarthritis. Tissue engineering techniques bring new hope for AC regeneration. To meet the regenerative requirements of the heterogeneous and layered structure of native AC tissue, a substantial number of multilayered biomimetic scaffolds have been studied. Ideal multilayered scaffolds should generate zone-specific functional tissue similar to native AC tissue. This review focuses on the current status of multilayered scaffolds developed for AC defect repair, including design strategies based on the degree of defect severity and the zone-specific characteristics of AC tissue, the selection and composition of biomaterials, and techniques for design and manufacturing. The challenges and future perspectives of biomimetic multilayered scaffold strategies for AC regeneration are also discussed.
Project description:Microtia, frequently encountered in plastic surgery practice, is usually corrected by auricular reconstruction with prostheses or autologous cartilages. In recent decades, however, cartilage tissue engineering has been emerging as a promising alternative for its minimal invasion and low immunogenicity. As a critical factor for tissue engineering, scaffolds are expected to be sufficiently porous and stiff to facilitate chondrogenesis. In this work, we introduce novel poly-l-lactic acid (PLLA) porous microsphere-reinforced silk-based hybrid (SBH) scaffolds with a multihierarchical porous structure. The scaffolds are fabricated by embedding PLLA porous microspheres (PMs) into a blending matrix of silk fibroin (SF) and gelatin solution, followed by mixing with a degummed silk fiber mesh and freeze-drying process. Through adjusting the amount of PLLA PMs, the mechanical strength approximates to natural cartilage and also balanced physical properties were realized. Biological evaluations of SBH scaffolds, both in vitro and in vivo, were conducted and PM-free plain silk-based (PSB) scaffolds were applied as control. Overall, it suggests that the incorporation of PLLA PMs remarkably improves mechanical properties and the capability to promote chondrogenesis of SBH scaffolds, and that SBH scaffolds appear to be a promising construct for potential applications in auricular cartilage tissue engineering and relevant fields.
Project description:Development of artificial materials for the facilitation of cartilage regeneration remains an important challenge in orthopedic practice. Our study investigates the potential for neocartilage formation within a synthetic polyester scaffold based on the polymerization of high internal phase emulsions. The fabrication of polyHIPE polymer (PHP) was specifically tailored to produce a highly porous (85%) structure with the primary pore size in the range of 50-170 μm for cartilage tissue engineering. The resulting PHP scaffold was proven biocompatible with human articular chondrocytes and viable cells were observed within the materials as evaluated using the Live/Dead assay and histological analysis. Chondrocytes with round nuclei were organized into multicellular layers on the PHP surface and were observed to grow approximately 300 μm into the scaffold interior. The accumulation of collagen type 2 was detected using immunohistochemistry and chondrogenic specific genes were expressed with favorable collagen type 2 to 1 ratio. In addition, PHP samples are biodegradable and their baseline mechanical properties are similar to those of native cartilage, which enhance chondrocyte cell growth and proliferation.
Project description:Osteoarthritis is the most common joint disorder affecting millions of people. Most scaffolds developed for cartilage regeneration fail due to vascularization and matrix mineralization. In this study we present a chondrogenic extracellular matrix (ECM) incorporated collagen/chitosan scaffold (chondrogenic ECM scaffold) for potential use in cartilage regenerative therapy. Biochemical characterization showed that these scaffolds possess key pro-chondrogenic ECM components and growth factors. MRI characterization showed that the scaffolds possess mechanical properties and diffusion characteristics important for cartilage tissue regeneration. In vivo implantation of the chondrogenic ECM scaffolds with bone marrow derived mesenchymal stem cells (MSCs) triggered chondrogenic differentiation of the MSCs without the need for external stimulus. Finally, results from in vivo MRI experiments indicate that the chondrogenic ECM scaffolds are stable and possess MR properties on par with native cartilage. Based on our results, we envision that such ECM incorporated scaffolds have great potential in cartilage regenerative therapy. Additionally, our validation of MR parameters with histology and biochemical analysis indicates the ability of MRI techniques to track the progress of our ECM scaffolds non-invasively in vivo; highlighting the translatory potential of this technology.
Project description:Inflammation is a major impediment to the healing of cartilage injuries, yet bioactive scaffolds suitable for cartilage repair in inflammatory environments are extremely rare. Herein, we utilized electrospinning to fabricate a two-dimensional nanofiber scaffold (2DS), which was then subjected to gas foaming to obtain a three-dimensional scaffold (3DS). 3DS was modified with metal phenolic networks (MPNs) composed of epigallocatechin gallate (EGCG) and strontium ions (Sr2+) to afford a MPNs-modified 3D scaffold (3DS-E). Gas-foamed scaffold exhibited multilayered structure conducive to cellular infiltration and proliferation. Compared to other groups, 3DS-E better preserved chondrocytes under interleukin (IL)-1β induced inflammatory environment, showing less apoptosis of chondrocytes and higher expression of cartilage matrix. Additionally, 3DS-E facilitated the regeneration of more mature cartilage in vivo, reduced cell apoptosis, and decreased the expression of pro-inflammatory cytokines. Taken together, 3DS-E may offer an ideal candidate for cartilage regeneration.
Project description:It remains scientifically challenging to regenerate injured cartilage in orthopedics. Recently, an endogenous cell recruitment strategy based on a combination of acellular scaffolds and chemoattractants to specifically and effectively recruit host cells and promote chondrogenic differentiation has brought new hope for in situ articular cartilage regeneration. In this study, a transforming growth factor-β3 (TGF-β3)-loaded biomimetic natural scaffold based on demineralized cancellous bone (DCB) and acellular cartilage extracellular matrix (ECM) was developed and found to improve chondral repair by enhancing cell migration and chondrogenesis. The DCB/ECM scaffold has porous microstructures (pore size: 67.76 ± 8.95 μm; porosity: 71.04 ± 1.62%), allowing the prolonged release of TGF-β3 (up to 50% after 42 days in vitro) and infrapatellar fat pad adipose-derived stem cells (IPFSCs) that maintain high cell viability (>96%) and favorable cell distribution and phenotype after seeding onto the DCB/ECM scaffold. The DCB/ECM scaffold itself can also provide a sustained release system to effectively promote IPFSC migration (nearly twofold in vitro). Moreover, TGF-β3 loaded on scaffolds showed enhanced chondrogenic differentiation (such as collagen II, ACAN, and SOX9) of IPFSCs after 3 weeks of culture. After implanting the composite scaffold into the knee joints of rabbits, enhanced chondrogenic differentiation was discovered at 1, 2, and 4 weeks post-surgery, and improved repair of cartilage defects in terms of biochemical, biomechanical, radiological, and histological results was identified at 3 and 6 months post-implantation. To conclude, our study demonstrates that the growth factor (GF)-loaded scaffold can facilitate cell homing, migration, and chondrogenic differentiation and promote the reconstructive effects of in vivo cartilage formation, revealing that this staged regeneration strategy combined with endogenous cell recruitment and pro-chondrogenesis is promising for in situ articular cartilage regeneration.