[Show abstract][Hide abstract] ABSTRACT: We developed an ultra-purified in situ forming gel as an injectable delivery vehicle of bone marrow stromal cells (BMSCs). Our objective was to assess reparative tissues treated with autologous BMSCs implanted using the injectable implantation system into osteochondral defects in a canine model. Forty-eight osteochondral defects in the patella groove of the knee joint were created in 12 adult beagle dogs (two defects in each knee). The defects were divided into a defect group (n = 16), an acellular novel material implantation (material) group (n = 16), and a BMSCs implantation using the current vehicle system (material with BMSCs) group (n = 16). The reparative tissues at 16 weeks postoperatively were assessed through gross, histological, and mechanical analyses. The reparative tissues of the material with BMSCs group were substituted with firm and smooth hyaline-like cartilage tissue that was perfectly integrated into the host tissues. This treatment group obviously enhanced the subchondral bone reconstruction. The compressive modulus of the reparative tissues was significantly higher in the material with BMSCs group than the other groups. This study demonstrated that the implantation of BMSCs using our novel in situ forming material induced a mature hyaline-like cartilage repair of osteochondral defects in a canine model.
No preview · Article · Jan 2012 · Journal of Biomedical Materials Research Part A
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to determine whether the local administration of stromal cell-derived factor-1 (SDF-1) using ultrapurified alginate gel (UPAL gel) could improve reparative tissues of osteochondral defects compared with those without treatment. For the investigation, a full-thickness osteochondral defect 4.5 mm in diameter and 3 mm in depth was created in the patella groove of the distal femur in rabbits. Local expression of SDF-1 protein was temporarily upregulated at 1 week after creating the osteochondral defect. The local administration of SDF-1 enhanced the migration of host cells, mainly bone marrow stromal cells (BMSCs), to the site of the osteochondral defect. In vitro cell migration assay supported this result. In the SDF-1 (UPAL gel containing SDF-1) treatment group, the histological scores and the compressive modulus of reparative tissues were significantly improved compared with the no-treatment and vehicle (UPAL gel without SDF-1) groups. On the other hand, SDF-1 did not influence the cellular proliferation and chondrogenesis of BMSCs. Based on the results obtained here, we speculate that SDF-1 enhances the reparative process of osteochondral injuries not through direct effects on the behavior of host cells, but through increased migration of host cells to the injured site. UPAL gel, as a vehicle material, may play an important role in chondrogenesis of recruited cells, mainly BMSCs. The cell-free approach with local administration of SDF-1 may be an effective strategy for developing a minimally invasive technique for cartilage tissue regeneration.
Preview · Article · Nov 2011 · Tissue Engineering Part A
[Show abstract][Hide abstract] ABSTRACT: We developed a novel cellular implantation system using an in situ forming ultra-purified alginate gel with quite low endotoxity. The aims of this study were to determine the superiority of chondrogenic potential of bone marrow stromal cells (BMSCs) cultured in the purified alginate gel compared with a commercial grade gel, and to assess reparative tissues treated with BMSCs implanted using the developed system into cartilage defects in rabbit knees. The effects of each alginate gel on cellular proliferation and chondrogenesis of rabbit BMSCs were determined by in vitro assessments. Using our purified alginate gel, a novel vehicle system for injecting BMSCs into osteochondral defects without periosteal patch was successfully established in this animal models. The in vitro analyses demonstrated that the purification of alginate significantly enhanced the cellular proliferation and chondrogenic differentiation of BMSCs. The in vivo assessments suggested that the implantation of BMSCs with the developed system using the purified alginate gel histologically and mechanically improved the reparative tissue of osteochondral defects. This system using the purified alginate gel shows the clinical potential for arthroscopically injectable implantation of BMSCs for the treatment of cartilaginous lesions.
No preview · Article · Sep 2010 · Journal of Biomedical Materials Research Part A
[Show abstract][Hide abstract] ABSTRACT: In this study, we successfully developed two types of volume-reduced three-dimensional scaffolds, including cushion- and cylinder-shape scaffolds, fabricated from chitosan-based hyaluronic acid hybrid polymer fibers. Using these scaffolds combined with a bioreactor system, we regenerated histologically and mechanically mature cartilage constructs. The final goal of this study was to clarify the ability of this engineered cartilage construct to induce cartilage repair in osteochondral defects. The mature cartilage constructs regenerated with two types of scaffolds were implanted into 5-mm diameter osteochondral defects in the patellar groove of rabbits. At 12 weeks after implantation, the reparative tissues consisted of hyaline-like cartilage with evidence of stable fusion to adjacent native cartilage and normal reconstitution of subchondral bone. The histological score of these tissues significantly outranked the value of untreated tissue. Biomechanically, compression modulus of reparative tissue at 12 weeks postoperatively was comparative to that of normal articular cartilage. Our results indicate that the implantation of constructs with mature cartilage have potential as a better approach for joint resurfacing.
No preview · Article · Jul 2008 · Journal of Biomedical Materials Research Part A