First-in-Human Pilot Study of Implantation of a Scaffold-Free Tissue-Engineered Construct Generated From Autologous Synovial Mesenchymal Stem Cells for Repair of Knee Chondral Lesions.

BACKGROUND: Articular cartilage has limited healing capacity, owing in part to poor vascularity and innervation. Once injured, it cannot be repaired, typically leading to high risk for developing osteoarthritis. Thus, cell-based and/or tissue-engineered approaches have been investigated; however, no approach has yet achieved safety and regenerative repair capacity via a simple implantation procedure. PURPOSE: To assess the safety and efficacy of using a scaffold-free tissue-engineered construct (TEC) derived from autologous synovial membrane mesenchymal stem cells (MSCs) for effective cartilage repair. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Five patients with symptomatic knee chondral lesions (1.5-3.0 cm2) on the medial femoral condyle, lateral femoral condyle, or femoral groove were included. Synovial MSCs were isolated from arthroscopic biopsy specimens and cultured to develop a TEC that matched the lesion size. The TECs were then implanted into chondral defects without fixation and assessed up to 24 months postoperatively. The primary outcome was the safety of the procedure. Secondary outcomes were self-assessed clinical scores, arthroscopy, tissue biopsy, and magnetic resonance image-based estimation of morphologic and compositional quality of the repair tissue. RESULTS: No adverse events were recorded, and self-assessed clinical scores for pain, symptoms, activities of daily living, sports activity, and quality of life were significantly improved at 24 months after surgery. Secure defect filling was confirmed by second-look arthroscopy and magnetic resonance imaging in all cases. Histology of biopsy specimens indicated repair tissue approaching the composition and structure of hyaline cartilage. CONCLUSION: Autologous scaffold-free TEC derived from synovial MSCs may be used for regenerative cartilage repair via a sutureless and simple implantation procedure. Registration: 000008266 (UMIN Clinical Trials Registry number).

Time-Dependent Recovery of Human Synovial Membrane Mesenchymal Stem Cell Function After High-Dose Steroid Therapy: Case Report and Laboratory Study.

BACKGROUND: The use of mesenchymal stem cells from various tissue sources to repair injured tissues has been explored over the past decade in large preclinical models and is now moving into the clinic. PURPOSE: To report the case of a patient who exhibited compromised mesenchymal stem cell (MSC) function shortly after use of high-dose steroid to treat Bell's palsy, who recovered 7 weeks after therapy. STUDY DESIGN: Case report and controlled laboratory study. METHODS: A patient enrolled in a first-in-human clinical trial for autologous implantation of a scaffold-free tissue engineered construct (TEC) derived from synovial MSCs for chondral lesion repair had a week of high-dose steroid therapy for Bell's palsy. Synovial tissue was harvested for MSC preparation after a 3-week recovery period and again at 7 weeks after therapy. RESULTS: The MSC proliferation rates and cell surface marker expression profiles from the 3-week sample met conditions for further processing. However, the cells failed to generate a functional TEC. In contrast, MSCs harvested at 7 weeks after steroid therapy were functional in this regard. Further in vitro studies with MSCs and steroids indicated that the effect of in vivo steroids was likely a direct effect of the drug on the MSCs. CONCLUSION: This case suggests that MSCs are transiently compromised after high-dose steroid therapy and that careful consideration regarding timing of MSC harvest is critical. CLINICAL RELEVANCE: The drug profiles of MSC donors and recipients must be carefully monitored to optimize opportunities to successfully repair damaged tissues.

Preparation of Scaffold-Free Tissue-Engineered Constructs Derived from Human Synovial Mesenchymal Stem Cells Under Low Oxygen Tension Enhances Their Chondrogenic Differentiation Capacity.

Low oxygen tension (LOT) has been reported to promote chondrogenic differentiation and prevent cellular senescence of stem cells. Therefore, the introduction of LOT conditions into conventional tissue engineering processes could further improve the potential of the constructs generated for cartilage repair. The purpose of this study was to elucidate the feasibility of LOT preparation on the chondrogenic differentiation of a scaffold-free tissue-engineered construct (TEC) derived from synovial mesenchymal stem cells (MSCs), construct whose feasibility for cartilage repair has been demonstrated in previous preclinical and clinical studies. Culture of MSCs under LOT conditions prevented cellular senescence and promoted the proliferative capacity of human synovial MSCs. In addition, TEC prepared from human synovial MSCs under LOT conditions (5% O2; LOT-TEC) showed superior in vitro chondrogenic differentiation capacity compared to that prepared under the usual 20% O2 (normal oxygen tension [NOT]; NOT-TEC), with elevated glycosaminoglycan production and elevated levels of chondrogenic marker gene expression. Notably, LOT-TEC differentiated into a hyaline-like cartilaginous tissue of approximately 1 cm in diameter without the detectable presence of fibrous tissue, while conventional NOT-TEC differentiated into a mixture of hyaline-like and fibrocartilaginous tissues. This is the first demonstration of in vitro development of a hyaline-like cartilaginous tissue of an implantable size to chondral lesion that was derived from human MSCs without the use of an exogenous scaffold. The manipulation of oxygen tension is a safe procedure with low cost and, thus, may be a clinically relevant option to improve the quality of TEC-mediated cartilage repair.

Optimization of human mesenchymal stem cell isolation from synovial membrane: Implications for subsequent tissue engineering effectiveness.

Synovium-derived mesenchymal stem cells (SDMSCs) are one of the most suitable sources for cartilage repair because of their chondrogenic and proliferative capacity. However, the isolation methods for SDMSCs have not been extensively characterized. Thus, our aim in this study was to optimize the processes of enzymatic isolation followed by culture expansion in order to increase the number of SDMSCs obtained from the original tissue. Human synovium obtained from 18 donors (1.5 g/donor) was divided into three aliquots. The samples were minced and subjected to collagenase digestion, followed by different procedures: Group 1, Tissue fragments were removed by filtering followed by removing floating tissue; Group 2, No filtering. Only floating fragments were removed; Group 3, No fragments were removed. Subsequently, each aliquot was sub-divided into two density subgroups with half. In Group 1, the cell-containing media was plated either at high (5000 cells/cm2) or low density (1000 cells/cm2). In Groups 2 and 3, the media containing cells and tissue was plated onto the same number of culture dishes as used in Group 1, either at high or low density. At every passage, the cells plated at high density were consistently re-plated at high and those plated at low density were likewise. The expanded cell yields at day 21 following cell isolation were calculated. These cell populations were then evaluated for their osteogenic, adipogenic, and chondrogenic differentiation capabilities. The final cell yields per 0.25 g tissue in Group 1 were similar at high and low density, while those in Groups 2 and 3 exhibited higher when cultured at low density. The cell yields at low density were 0.7 ± 1.2 × 107 in Group 1, 5.7 ± 1.1 × 107 in Group 2, 4.3 ± 1.2 × 107 in Group 3 (Group 1 vs Groups 2 and 3, p < 0.05). In addition, the cells obtained in each low density subgroup exhibited equivalent osteogenic, adipogenic, and chondrogenic differentiation. Thus, it was evident that filtering leads to a loss of cells and does not affect the differentiation capacities. In conclusion, exclusion of a filtering procedure could contribute to obtain higher number of SDMSCs from synovial membrane without losing differentiation capacities.

Repairing Osteochondral Defects of Critical Size Using Multiple Costal Grafts: An Experimental Study.

OBJECTIVE: To investigate the feasibility of repairing osteochondral defects of critical size by performing mosaicplasty using multiple sliced costal cartilage grafts, which enables repair of extensively injured knees using grafts from a single rib. DESIGN: Critical osteochondral defects were prepared on the femoral groove of skeletally mature Japanese white rabbits. Costal cartilage grafts from a single rib were harvested and sliced into multiple segments (approximately 3-5 mm in length). The defects were left untreated or repaired by performing mosaicplasty using costal cartilage grafts (with or without a longitudinal cut along the middle). At 4 and 12 weeks after transplantation, International Cartilage Repair Society macroscopic and histological grading was performed. RESULTS: The macroscopic score and visual histological score were significantly higher in the repaired groups than in the untreated group at 4 and 12 weeks after surgery. Histological continuous integration between grafted costal cartilage and host bone was observed in both repaired groups. CONCLUSIONS: The findings suggest that costal cartilage might be a useful alternative source for chondral grafting. We were able to repair large osteochondral defects by performing mosaicplasty using multiple sliced costal cartilage grafts from a single rib.

Next Generation Mesenchymal Stem Cell (MSC)-Based Cartilage Repair Using Scaffold-Free Tissue Engineered Constructs Generated with Synovial Mesenchymal Stem Cells.

Because of its limited healing capacity, treatments for articular cartilage injuries are still challenging. Since the first report by Brittberg, autologous chondrocyte implantation has been extensively studied. Recently, as an alternative for chondrocyte-based therapy, mesenchymal stem cell-based therapy has received considerable research attention because of the relative ease in handling for tissue harvest, and subsequent cell expansion and differentiation. This review summarizes latest development of stem cell therapies in cartilage repair with special attention to scaffold-free approaches.