Yoshiki Tani

T2 mapping is an MRI method particularly reflective of the collagen arrangement in the cartilage, and diffusion tensor (DT) imaging captures the diffusion of water molecules. Laser-induced photoacoustic measurement (LIPA) makes it possible to assess not only the thickness of the cartilage layer but also its viscoelastic properties. By assessing cartilage damage assessment using LIPA and 3.0 Tesla MRI (T2 mapping and DT imaging), this study investigates the usefulness of the various methods. The International Cartilage Repair Society (ICRS) classification was used to classify 29 bone cartilage pieces excised during surgical procedures. At the same time, LIPA was performed at sites matching the area of cartilage damage. MRI was performed preoperatively to measure the T2 and the apparent diffusion coefficient. In addition, tissue sections for histological assessment using the Mankin score were prepared for each ICRS grade, and the results with the various methods were compared. With DT imaging, significant differences were observed in all grades (P < 0.01). With T2 mapping, significant differences were observed in all grades except for grade 1 versus grade 2 (P < 0.01). With LIPA, significant differences were observed in ICRS grade 1 versus grade 3 (P < 0.05), grade 1 versus grade 4 (P < 0.01), grade 2 versus grade 4 (P < 0.01), and grade 3 versus grade 4 (P < 0.05). With the Mankin score, significant differences were observed in ICRS grade 1 versus grade 3 (P < 0.01), grade 1 versus grade 4 (P < 0.01), grade 2 versus grade 4 (P < 0.01), and grade 3 versus grade 4 (P < 0.01). Correlations were observed in all combinations of ICRS grade with DT imaging, T2 mapping, LIPA, and Mankin score. Correlations were observed between the degree of histological degeneration and DT imaging, T2 mapping, and ICRS grade, but LIPA had a weaker correlation than MRI. In the assessment of knee osteoarthritis, there are instances where it is difficult to assess the damaged cartilage site with MRI alone, and we believe that it is desirable to use a combination of LIPA and MRI.

Introduction: Angiogenesis is an important factor in the development of osteoarthritis (OA). We investigated the efficacy of bevacizumab, an antibody against vascular endothelial growth factor and an inhibitor of angiogenesis, in the treatment of OA using a rabbit model of anterior cruciate ligament transection. Methods: First, we evaluated the response of gene expression and histology of the normal joint to bevacizumab treatment. Next, in a rabbit model of OA induced by anterior cruciate ligament transection, we used macroscopic and histological evaluations and real-time polymerase chain reaction (PCR) to examine the responses to intravenous (systemic) administration of bevacizumab (OAB IV group). We also investigated the efficacy of intra-articular (local) administration of bevacizumab in OA-induced rabbits (OAB IA group). Results: Histologically, bevacizumab had no negative effect in normal joints. Bevacizumab did not increase the expression of genes for catabolic factors in the synovium, subchondral bone, or articular cartilage, but it increased the expression of collagen type 2 in the articular cartilage. Macroscopically and histologically, the OAB IV group exhibited a reduction in articular cartilage degeneration and less osteophyte formation and synovitis compared with the control group (no bevacizumab; OA group). Real-time PCR showed significantly lower expression of catabolic factors in the synovium in the OAB IV group compared with the OA group. In articular cartilage, expression levels of aggrecan, collagen type 2, and chondromodulin-1 were higher in the OAB IV group than in the OA group. Histological evaluation and assessment of pain behaviour showed a superior effect in the OAB IA group compared with the OAB IV group 12 weeks after administration of bevacizumab, even though the total dosage given to the OAB IA group was half that received by the OAB IV group. Conclusions: Considering the dosage and potential adverse effects of bevacizumab, the local administration of bevacizumab is a more advantageous approach than systemic administration. Our results suggest that intra-articular bevacizumab may offer a new therapeutic approach for patients with post-traumatic OA.