Naofumi Okamoto

Treating Achilles Tendon Rupture in Rats with Bone-Marrow-Cell Transplantation Therapy

BACKGROUND Bone marrow cells possess multipotentiality and have been used for several treatments. We hypothesized that bone marrow cells might differentiate into regenerated tendon and that several cytokines within bone marrow cells might accelerate tendon healing. Therefore, we treated Achilles tendon ruptures in a rat model with transplantation of whole bone marrow cells. METHODS Nine F344/Nslc (Fisher) rats were the source of bone marrow cells and mesenchymal stem cells as well as normal Achilles tendons. Eighty-seven Fisher rats were used for the experiments. The rats were divided into three groups: the BMC group (bone marrow cells injected around the tendon), the MSC group (mesenchymal stem cells injected around the tendon), and the non-treated control group (incision only). Outcome measures included mechanical testing, collagen immunohistochemistry, histological analysis, and reverse transcription-polymerase chain reaction to detect expression of transforming growth factor-β (TGF-β) and vascular endothelial growth factor (VEGF). RESULTS The ultimate failure load in the BMC group was significantly greater than that in the non-treated or the MSC group at seven days after incision (3.8 N vs. 0.9 N or 2.1 N, p < 0.016) and at fourteen days after incision (10.2 N vs. 6.1 N or 8.2 N, p < 0.016). The ultimate failure load in the BMC group at twenty-eight days after incision (33.8 N) was the same as that of normal tendon (34.8 N). The BMC group demonstrated stronger staining for type-III collagen at seven days after incision and stronger staining for type-I collagen at twenty-eight days than did the MSC group. Expression of TGF-β and VEGF in the BMC group was significantly increased compared with that in the other groups at four days after incision (TGF-β: 1.6 vs. 1.3 or 0.6, p < 0.01; VEGF: 1.7 vs. 1.1 or 0.9, p < 0.01). CONCLUSIONS Transplantation of whole bone marrow cells may be a better and more readily available treatment for Achilles tendon rupture than cultured mesenchymal stem cells.

New Strategies for Anterior Cruciate Ligament Partial Rupture Using Bone Marrow Transplantation in Rats

The purpose of this study was to compare anterior cruciate ligament (ACL) regeneration between animal groups subjected to intra-articular injection of fresh whole bone marrow cells (BMCs), cultured mesenchymal stem cells (MSCs), or saline. Partially transected ACLs in Fischer 344/Nslc rats were prepared, followed by injection of BMCs, MSCs, or saline into the articular cavity at 1 week after transection. Donor cells expressing green fluorescent protein were detected in the recipients transected ACLs at 4 weeks in the BMC and MSC groups, and their ACLs appeared almost normal histologically. Further, there were significantly more mature spindle cells in the BMC group than in the saline group at 4 weeks. Biomechanically, the tensile strength in the BMC group reached near normal levels at 4 weeks after injection. The levels of transforming growth factor-β1 in the ACL tissue and knee joint fluid in the BMC group were increased significantly compared with that of the saline group at 4 weeks as detected by immunohistochemical analysis. In conclusion, intra-articular bone marrow transplantation using fresh whole BMCs is an effective treatment for ACL partial rupture. This therapy is easy to apply in a clinical setting because no culture system is required for collecting MSCs.

Allogeneic intra-bone marrow transplantation prevents rheumatoidarthritis in SKG/Jcl mice

The treatment of autoimmune diseases by allogeneic bone marrow transplantation remains a promising therapeutic avenue. However, more intensive studies on murine models are essential before application to a large number of human patients. In particular, the use of bone marrow transplantation to treat rheumatoid arthritis has been problematic. We have taken advantage of the SKG/Jcl mouse that develops a chronic T cell-mediated autoimmune disease that mimics rheumatoid arthritis which attempted to prevent the development of immunopathology in these mice by allogeneic bone marrow transplantation (BMT). In particular, we utilized our unique technology in which bone marrow cells (BMCs) of control C57BL/6J mice are directly injected into the bone marrow cavity in the tibia of SKG mice (intra-bone marrow [IBM]-BMT). As controls, SKG/Jcl mice were transplanted with whole BMCs from syngeneic SKG mice. Importantly, 12 months after IBM-BMT [B6-->SKG] demonstrated no evidence of arthritis, whereas the control [SKG-->SKG] mice demonstrated, the expected immunopathology of a rheumatoid arthritis-like condition. Further, hematolymphoid cells in [B6-->SKG] mice were reconstituted by donor-derived cells and the percentages of Treg (Foxp3+/CD4+) cells, the percentages of receptor activator of nuclear factor-kappaB ligand (RANKL)+ cells on the CD4+ T cells and the serum levels of tumor necrosis factor-alpha, interleukin-1 and interleukin-6 were normalized in the [B6-->SKG] mice. These data suggest that IBM-BMT is a viable method of immunological manipulation that suppresses the severe joint destruction and bone absorption in SKG/Jcl mice and lends further credence to the use of this methodology in humans with intractable rheumatoid arthritis.