Synovium extra cellular matrices seeded with transduced mesenchymal stem cells stimulate chondrocyte maturation in vitro and cartilage healing in clinically-induced rat-knee lesions in vivo.
Authors: Reisbig Nathalie A, Pinnell Erin, Scheuerman Logan, Hussein Hayam, Bertone Alicia L
Journal: PloS one
Summary
# Editorial Summary Osteoarthritis develops when cartilage damage exceeds the joint's inherent repair capacity, making novel therapeutic approaches critical for equine practice. Researchers engineered synovial constructs by seeding decellularised synovial extracellular matrix scaffolds with genetically modified mesenchymal stem cells (either expressing GFP or bone morphogenetic protein-2), then evaluated their chondrogenic effects both in vitro with co-cultured chondrocytes and in vivo using surgically-induced full-thickness cartilage lesions in rat knees. In vitro, the BMP-2-modified constructs produced the greatest enhancement of chondrocyte proliferation, viability, and type II collagen production, whilst reciprocal signalling from chondrocytes stimulated the constructs to release hyaluronic acid, proteoglycans, and additional BMP-2. At five weeks post-implantation adjacent to lesion sites, BMP-2-constructs demonstrated significantly superior cartilage growth and subchondral bone repair compared to scaffold-alone controls, with immunohistochemistry confirming robust engraftment of implanted stem cells and their continued gene expression within the lesion microenvironment. These findings suggest that synovial construct transplantation offers substantial promise for stimulating cartilage and bone repair through both cell-mediated and soluble factor-mediated mechanisms, potentially arresting osteoarthritic progression—though translation to equine joints requires further investigation regarding implantation site optimisation, construct longevity, and functional outcome measures in weight-bearing limbs.
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Practical Takeaways
- •Synovium-based stem cell constructs represent a proof-of-concept regenerative approach to cartilage repair that may eventually prevent osteoarthritis progression following traumatic joint injury.
- •BMP-2 gene engineering of mesenchymal stem cell constructs substantially enhanced their chondrogenic potency both in laboratory and in vivo animal models, suggesting optimized construct design matters.
- •This technology requires further development before clinical application in horses, but the equine-derived constructs used in this research indicate species-specific refinement is underway.
Key Findings
- •Synovium-derived mesenchymal stem cell constructs (sConstructs) seeded on decellularized synovium matrix significantly increased chondrocyte proliferation, viability, and collagen II production in vitro, with greatest effect from BMP-2-engineered constructs.
- •BMP-2-sConstructs implanted adjacent to rat knee cartilage lesions produced significantly greater cartilage repair, adjacent cartilage growth, and subchondral bone healing at 5 weeks compared to control sECM alone.
- •Endogenous cell migration into constructs and continued gene expression of implanted mesenchymal stem cells were confirmed via immunohistochemistry and GFP tracking in vivo.
- •The therapeutic effect was mediated by soluble extracellular matrix factors, cell-derived factors, and upregulation of anabolic proteins including BMP-2, demonstrating a positive feedback loop between chondrocytes and construct cells.