Decellularized Meniscus (Mend) as a Biomaterial That Supports Stem Cell Invasion and Chondrogenesis

Cartilage damage affects 25 million people annually due to trauma, sports injuries, and wear and tear. Mesenchymal stem cells (MSCs) are commonly used for tissue-engineered cartilage repair due to their accessibility and proliferation capacity compared to chondrocytes. However, MSC-based approaches often result in non-uniform matrix secretion and limited chondrogenesis in 3D hydrogels. Incorporating cartilage-derived extracellular matrix (ECM) into constructs can enhance chondrogenesis. Building on this concept, the Gottardi lab developed a novel scaffold made from decellularized porcine meniscus (MEND). MEND retains mechanical properties suitable for cartilage repair, offers high porosity for cell infiltration, and is generated via selective elastin removal. This study investigates whether MEND supports MSC recellularization and possesses intrinsic pro-chondrogenic potential. MEND is compared to traditional hydrogels, such as methacrylated type I collagen (ColMA) and gelatin-hyaluronic acid (GelMA/HAMA). MEND Fabrication : Porcine meniscus sections were enzymatically processed to remove elastin while preserving mechanical integrity. Cylinders were punched from the red zone region, pre-soaked in serum-containing medium, and seeded with MSCs at varying densities. Hydrogel Constructs and Controls : MSCs were cultured in ColMA and GelMA/HAMA hydrogels or as pellets for positive controls. All constructs were cultured in chondrogenic medium for 21 days. Analysis : Chondrogenesis was assessed via histology, immunofluorescence, RT-qPCR, and biochemistry, focusing on GAG and collagen production. Hydrogels : ColMA and GelMA/HAMA constructs exhibited non-uniform matrix secretion after 21 days, with sporadic GAG and collagen expression in ColMA and variability in GelMA/HAMA, as well as substantive contraction of ColMA hydrogels. MEND : Structural analyses confirmed elastin removal, decellularization, porosity (8%), and channels diameters averaging 8µm. MSCs successfully seeded into MEND with uniform distribution and viability. MEND's porosity enables effective MSC infiltration and distribution, addressing limitations of existing hydrogels. Initial chondrogenesis in pellets and hydrogels showed dis-homogeneous matrix secretion. We observed good differentiation in all conditions and used non-canonical amino acids to directly tag newly synthetized matrix. MEND's ECM composition, including collagen I, II, and hyaluronic acid, provides a cartilage-like environment conducive to chondrogenesis, albeit not chondrogenic in and of itself. Without any contraction, MEND offers a promising scaffold for articular cartilage engineering due to its cartilage-like composition, mechanical properties, and capacity for MSC repopulation.