Self-assembled meniscus-specific ECM membrane promotes cell migration and vascular ingrowth for meniscus repair and reconstruction.

BACKGROUND: The knee meniscus has limited intrinsic repair and regenerative capacity. Safe and effective biotherapeutic products remain lacking, and enhancing cell migration and angiogenesis remains a major challenge. This study aimed to develop a novel self-assembled meniscus-specific extracellular matrix membrane (saECM-M) and evaluate its performance in scaffold-free meniscus repair and scaffold-guided whole-meniscus reconstruction, in comparison with chemically processed decellularized ECM (cpd-ECM).

METHODS: Meniscal fibrochondrocytes (MFCs) were cultured under membrane-inducing conditions to generate saECM-M in vitro. Its bioactivity was evaluated by cell migration and endothelial network formation assays in vitro and by a scaffold-free meniscus defect repair model in vivo. For whole-meniscus reconstruction, saECM-M was integrated with a biomimetic 3D-printed poly(ε-caprolactone) (PCL) scaffold to guide ECM alignment and provide mechanical support. PCL scaffolds seeded with MFCs alone or combined with cpd-ECM served as controls. Meniscus regeneration was assessed in a rabbit meniscectomy model using imaging, histological, and biomechanical analyses, including chondroprotective evaluation. Transcriptomic profiling and proteomics were performed to investigate molecular pathways associated with saECM-M-mediated cell migration and vascular ingrowth.

RESULTS: saECM-M was characterized as a cell-laden membrane enriched with native meniscus-like ECM components. In vitro, saECM-M significantly enhanced cell migration and endothelial network formation compared with cpd-ECM (approximately 1.2-fold and 2-fold, respectively; P < 0.05), accompanied by increased collagen deposition. In vivo, isolated saECM-M promoted superior meniscus defect repair. When integrated with the biomimetic PCL scaffold, saECM-M further promoted aligned collagen organization, vascular ingrowth, and robust meniscus regeneration. Compared with the PCL-cpd-ECM group, the PCL-saECM-M group showed improved host tissue integration on MRI (WORMS score: 10 ± 1 vs 32.3 ± 2.1), enhanced tensile mechanical properties (79 ± 2 MPa vs 64 ± 7.8 MPa), and superior chondroprotective effects (Mankin score: 1.67 ± 0.58 vs 6.67 ± 0.58) (P < 0.05). Transcriptomic and proteomic analyses identified enrichment of ECM-receptor interaction- and PI3K-AKT signaling-related pathways associated with saECM-M-enhanced cell migration and vascular ingrowth.

CONCLUSION: saECM-M functions as an intrinsically bioactive meniscus-derived matrix capable of promoting both scaffold-free repair and scaffold-guided reconstruction. Compared with cpd-ECM, saECM-M more effectively supports cell migration, angiogenesis, and organized collagen remodeling, leading to superior regenerative outcomes.

THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: saECM-M addresses an unmet clinical need as a cell-secreted, additive-free bioactive matrix. It may serve as a simple biologic augmentation for arthroscopic repair, while integration with an FDA-approved PCL scaffold offers a promising strategy for meniscus replacement with improved bioactivity and biocompatibility.