Demineralized Cortical Bone Matrix Augmented With Peripheral Blood-Derived Mesenchymal Stem Cells for Rabbit Medial Meniscal Reconstruction

Preclinical Studies and Clinical Trials on Cell-Based Treatments for Meniscus Regeneration

This study aims at performing a thorough review of cell-based treatment strategies for meniscus regeneration in preclinical and clinical studies. The PubMed, Embase, and Web of Science databases were searched for relevant studies (both preclinical and clinical) published from the time of database construction to December 2022. Data related to cell-based therapies for in situ regeneration of the meniscus were extracted independently by two researchers. Assessment of risk of bias was performed according to the Cochrane Handbook for Systematic Reviews of Interventions. Statistical analyses based on the classification of different treatment strategies were performed. A total of 5730 articles were retrieved, of which 72 preclinical studies and 6 clinical studies were included in this review. Mesenchymal stem cells (MSCs), especially bone marrow MSCs (BMSCs), were the most commonly used cell type. Among preclinical studies, rabbit was the most commonly used animal species, partial meniscectomy was the most commonly adopted injury pattern, and 12 weeks was the most frequently chosen final time point for assessing repair outcomes. A range of natural and synthetic materials were used to aid cell delivery as scaffolds, hydrogels, or other morphologies. In clinical trials, there was large variation in the dose of cells, ranging from 16 × 106 to 150 × 106 cells with an average of 41.52 × 106 cells. The selection of treatment strategy for meniscus repair should be based on the nature of the injury. Cell-based therapies incorporating various "combination" strategies such as co-culture, composite materials, and extra stimulation may offer greater promise than single strategies for effective meniscal tissue regeneration, restoring natural meniscal anisotropy, and eventually achieving clinical translation. Impact Statement This review provides an up-to-date and comprehensive overview of preclinical and clinical studies that tested cell-based treatments for meniscus regeneration. It presents novel perspectives on studies published in the past 30 years, giving consideration to the cell sources and dose selection, delivery methods, extra stimulation, animal models and injury patterns, timing of outcome assessment, and histological and biomechanical outcomes, as well as a summary of findings for individual studies. These unique insights will help to shape future research on the repair of meniscus lesions and inform the clinical translation of new cell-based tissue engineering strategies.

Allografts for partial meniscus repair: an in vitro and ex vivo meniscus culture study

The purpose of this study was to evaluate the treatment potential of a human-derived demineralized scaffold, Spongioflex® (SPX), in partial meniscal lesions by employing in vitro models. In the first step, the differentiation potential of human meniscal cells (MCs) was investigated. In the next step, the ability of SPX to accommodate and support the adherence and/or growth of MCs while maintaining their fibroblastic/chondrocytic properties was studied. Control scaffolds, including bovine collagen meniscus implant (CMI) and human meniscus allograft (M-Allo), were used for comparison purposes. In addition, the migration tendency of MCs from fresh donor meniscal tissue into SPX was investigated in an ex vivo model. The results showed that MCs cultured in osteogenic medium did not differentiate into osteogenic cells or form significant calcium phosphate deposits, although AP activity was relatively increased in these cells. Culturing cells on the scaffolds revealed increased viability on SPX compared to the other scaffold materials. Collagen I synthesis, assessed by ELISA, was similar in cells cultured in 2D and on SPX. MCs on micro-porous SPX (weight >0.5 g/cm3) exhibited increased osteogenic differentiation indicated by upregulated expression of ALP and RUNX2, while also showing upregulated expression of the chondrogen-specific SOX9 and ACAN genes. Ingrowth of cells on SPX was observed after 28 days of cultivation. Overall, the results suggest that SPX could be a promising biocompatible scaffold for meniscal regeneration.

Construction of Vascularized Tissue Engineered Bone with nHA-Coated BCP Bioceramics Loaded with Peripheral Blood-Derived MSC and EPC to Repair Large Segmental Femoral Bone Defect

The regenerative repair of segmental bone defect (SBD) is an urgent problem in the field of orthopedics. Rapid induction of angiogenesis and osteoinductivity after implantation of scaffold is critical. In this study, a unique tissue engineering strategy with mixture of peripheral blood-derived mesenchymal stem cells (PBMSC) and endothelial progenitor cells (PBEPC) was applied in a 3D-printed biphasic calcium phosphate (BCP) scaffold with highly bioactive nano hydroxyapatite (nHA) coating (nHA/BCP) to construct a novel vascularized tissue engineered bone (VTEB) for rabbit femoral SBD repair. The 2D coculture of PBMSC and PBEPC showed that they could promote the osteogenic or angiogenic differentiation of the cells from each other, especially in the group of PBEPC/PBMSC = 75:25. Besides, the 3D coculture results exhibited that the nHA coating could further promote PBEPC/PBMSC adhesion, proliferation, and osteogenic and angiogenic differentiation on the BCP scaffold. In vivo experiments showed that among the four groups (BCP, BCP-PBEPC/PBMSC, nHA/BCP, and nHA/BCP-PBEPC/PBMSC), the nHA/BCP-PBEPC/PBMSC group induced the best formation of blood vessels and new bone and, thus, the good repair of SBD. It revealed the synergistic effect of nHA and PBEPC/PBMSC on the angiogenesis and osteogenesis of the BCP scaffold. Therefore, the construction of VTEB in this study could provide a possibility for the regenerative repair of SBD.