K. Shimomura (Osaka, JP)Osaka University Graduate School of Medicine Department of Orthopaedic Surgery
Presenter Of 2 Presentations
12.3.7 - A novel approach to the treatment of meniscal hoop injuries using a mesenchymal stem cell-seeded electrospun nanofibrous scaffold
Damage to the meniscal hoop structure results in loss of biomechanical function. However, there have been no established, effective treatments for such injuries. The purpose of this study was to investigate the applicability of cell-seeded nanofibrous scaffolds to repair the damaged meniscal hoop structure along with the prevention of subsequent cartilage degeneration using a rabbit model.
Methods and Materials
Meniscal radial defects (5 mm width) in the medial meniscus were treated by wrapping and suturing with either an aligned electrospun nanofibrous scaffold alone (scaffold group, N=12) or a scaffold combined with a tissue engineered construct (TEC) derived from synovial mesenchymal stem cells (MSCs), (TEC-scaffold group, N=12), with the scaffold fiber direction matching that of the meniscal circumferential fibers. In the control group (N=12), no treatment was applied to the meniscal defect. Animals were euthanized at 4, 8, or 12 weeks after implant surgery. The distal femur and medial menisci of animals were used for histological analysis. As an evaluation of meniscal hoop function, the ratio of meniscal uncovered area on the medial tibial plateau is calculated.
Histologically, the articular cartilage on the medial femoral condyles of both the control and scaffold group animals showed evidence for accelerated development of osteoarthritis-like changes (Fig.1). Conversely, the TEC-scaffold group maintained the integrity of the structure of the hyaline cartilage until 12 weeks after surgery. Notably, the meniscal uncovered areas for the TEC-scaffold group did not become statistically worse with time, suggesting repair and stabilization of hoop structure integrity over time (Fig.2). Also, meniscal defects treated with such TEC-combined nanofibrous scaffolds were consistently repaired with a fibrocartilaginous tissue.
In this study, we have demonstrated the feasibility of a combined TEC-nanofibrous scaffold to repair the meniscal hoop structure, and prevent the progression to cartilage degeneration, as a potential tissue engineering method.
23.2.3 - Discrepancy between T2 mapping MRI and histological analyses for zonal composition of mesenchymal stem cell-based cartilage repair tissue
Quantitative magnetic resonance imaging (MRI) assessments such as T2 mapping have been recently studied to detect the biochemical composition and structure of articular cartilage. In the present study, we investigated the correlation of zonal image of T2 mapping MRI of the repair cartilage with the histology of biopsy specimen at the corresponding area in five patients who underwent the implantation of a scaffold-free tissue-engineered construct (TEC) generated from autologous synovial mesenchymal stem cells (MSCs) to an isolated cartilage lesions, and aim to elucidate the efficacy and limitation of T2 mapping MRI for the evaluation of cartilage repair.
Methods and Materials
We performed both T2 mapping MRI and histological evaluation of biopsy specimen at the identical area in all patients at 48 weeks postoperatively, and T2 values and histological scores were compared at superficial, middle and deep zone of repair tissue.
Histology showed that the repair tissue in the superficial zone was dominated by fibrous tissue and the ratio of hyaline-like matrix increased with the depth of the repair tissue, leading to the dominance by hyaline cartilage–like tissue in the deep zone (Figure 1). There was significant difference between superficial and middle/deep zones in histological scores. Conversely, there was no statistical significances in T2 value detected among zones (Figure 2). Accordingly, there were no correlations detected between histological scores and T2 values in each zone.
Such discrepancy of the data between T2 mapping and histology suggests that T2 mapping failed in detecting the collagen architecture and composition of repair cartilage. This suggests that the resolution of current quantitative MRI might not be enough to depict the difference in zonal collagen architecture in repair cartilage. Furthermore, although invasive, histologic assessment is likely still more reliable method for evaluation of tissue quality.