Katsuaki Kanbe

Synovectomy reduces stromal-cell-derived factor-1 (SDF-1) which is involved in the destruction of cartilage in osteoarthritis and rheumatoid arthritis

We have compared the concentrations of stromal-cell-derived factor-1 (SDF-1), matrix metalloproteinase-1 (MMP-1), MMP-9 and MMP-13 in serum before and after synovectomy or total knee replacement (TKR). We confirmed the presence of SDF-1 and its receptor CXCR4 in the synovium and articular cartilage by immunohistochemistry. We established chondrocytes by using mutant CXCR4 to block the release of MMPs. The level of SDF-1 was decreased 5.1- and 6.7-fold in the serum of patients with OA and RA respectively, after synovectomy compared with that before surgery. MMP-9 and MMP-13 were decreased in patients with OA and RA after synovectomy. We detected SDF-1 in the synovium and the bone marrow but not in cartilage. CXCR4 was detected in articular cartilage. SDF-1 increased the release of MMP-9 and MMP-13 from chondrocytes in a dose-dependent manner. The mutant CXCR4 blocked the release of MMP-9 and MMP-13 from chondrocytes by retrovirus vector. Synovectomy is effective in patients with OA or RA because SDF-1, which can regulate the release of MMP-9 and MMP-13 from articular chondrocytes for breakdown of cartilage, is removed by the operation.

Continuation of Methotrexate Resulted in Better Clinical and Radiographic Outcomes Than Discontinuation upon Starting Etanercept in Patients with Rheumatoid Arthritis: 52-week Results from the JESMR Study

Objective. The aim of the Efficacy and Safety of Etanercept on Active Rheumatoid Arthritis Despite Methotrexate Therapy in Japan (JESMR) study is to compare the efficacy of continuation versus discontinuation of methotrexate (MTX) when starting etanercept (ETN) in patients with active rheumatoid arthritis (RA). Methods. In total, 151 patients with active RA who had been taking MTX were randomized to either ETN 25 mg twice a week with 6–8 mg/week MTX (the E+M group), or ETN alone (the E group). The primary endpoint at Week 52 was the radiographic progression assessed by van der Heijde-modified Sharp score. Results. The mean progression in total score at Week 52 was not significantly different, statistically, between the E+M group and the E group (0.8 vs 3.6, respectively; p = 0.06). However, a significant difference was observed in radiographic progression between Weeks 24 and 52 (0.3 vs 2.5; p = 0.03), and the mean progression of the erosion score was negative in the E+M group, which was significantly better than the E group at Week 52 (–0.2 vs 1.8; p = 0.02). Clinically, the cumulative probability plot of the American College of Rheumatology (ACR)-N values at Week 52 clearly demonstrated a superior response in the E+M group than in the E group. ACR20, 50, and 70 response rates at Week 52 in the E+M group (86.3%, 76.7%, and 50.7%) were significantly greater than those in the E group (63.8%; p = 0.003, 43.5%; p < 0.0001 and 29.0%; p = 0.01, respectively). Conclusion. MTX should be continued when starting ETN in patients with active RA. (ClinicalTrials.gov: NCT00688103)

Stimulation of chondrocyte hypertrophy by chemokine stromal cell-derived factor 1 in the chondro-osseous junction during endochondral bone formation

During endochondral bone formation, chondrocytes undergo differentiation toward hypertrophy before they are replaced by bone and bone marrow. In this study, we found that a G-protein coupled receptor CXCR4 is predominantly expressed in hypertrophic chondrocytes, while its ligand, chemokine stromal cell-derived factor 1 (SDF-1) is expressed in the bone marrow adjacent to hypertrophic chondrocytes. Thus, they are expressed in a complementary pattern in the chondro-osseous junction of the growth plate. Transfection of a CXCR4 cDNA into pre-hypertrophic chondrocytes results in a dose-dependent increase of hypertrophic markers including Runx2, Col X, and MMP-13 in response to SDF-1 treatment. In organ culture SDF-1 infiltrates cartilage and accelerates growth plate hypertrophy. Furthermore, a continuous infusion of SDF-1 into the rabbit proximal tibial physis results in early physeal closure, which is accompanied by a transient elevation of type X collagen expression. Blocking SDF-1/CXCR4 interaction suppresses the expression of Runx2. Thus, interaction of SDF-1 and CXCR4 is required for Runx2 expression. Interestingly, knocking down Runx2 gene expression results in a decrease of CXCR4 mRNA levels in hypertrophic chondrocytes. This suggests a positive feedback loop of stimulation of chondrocyte hypertrophy by SDF-1/CXCR4, which is mediated by Runx2.

Pericellular matrilins regulate activation of chondrocytes by cyclic load-induced matrix deformation

Pericellular matrix is at the ideal location to be involved in transmitting mechanical signals from the microenvironment to a cell. We found that changes of the content of matrilins that link various pericellular molecules surrounding chondrocytes affect mechanical stimulation of chondrocyte proliferation and gene expression. Thus, pericellular matrilins may play a role in chondrocyte mechanotransduction.

Inducement of mitogen-activated protein kinases in frozen shoulders

BackgroundMitogen-activated protein (MAP) kinases are well-known molecules that play key roles in mechanical stress signals during skeletal development. To test our hypothesis that the synovium in frozen shoulders is induced by MAP kinases, immunohistochemical analyses for detecting expression and signal transduction of MAP kinases were performed in synovial tissue obtained from the rotator interval (RI) in frozen shoulders.MethodsSynovial tissues were examined from 10 frozen shoulder patients with a mean age of 55.4 years (46–62 years). Synovial tissues between the long head of the biceps tendon (LHB) and the RI in frozen shoulders were stained with hematoxylin and eosin (H&E) and then examined with immunohistochemical staining. Extracellular signal-regulated (ERK), the Jun N-terminal (JNK), and p38 mitogen-activated protein (MAP) kinases, nuclear factor κB (NF-κB), p50, CD29 (β1-integrin), matrix metalloproteinase (MMP)-3, interleukin-6 (IL-6), CD56, CD68, S-100, and vascular endothelial growth factor (VEGF) were analyzed to detect expression patterns.ResultsH&E showed vascular proliferation with fibrin and fibrous tissue in the synovium of frozen shoulders. ERK was expressed in the epithelial cells of vascular tissue, and JNK was expressed strongly in the interstitial cells around vascular tissue; p38 MAPK was not expressed. NF-κB was expressed in vascular tissue, and IL-6 was expressed around vascular tissue. CD29 (β1-integrin) was expressed in vascular tissue and in superficial cells of synovial tissue. MMP-3 and VEGF were expressed on the surface layer of synovial tissue and vascular tissue, and CD68 was expressed on the surface layer. Nerverelated proteins, CD56 and S-100, were expressed weakly.ConclusionsMechanical stress on the LHB and RI in the shoulder may induce ERK and JNK to express NF-κB by CD29 to develop capsule contracture, producing MMP-3, IL-6, and VEGF.

Clinical factors related to the efficacy and complications of orthopedic surgery for rheumatoid arthritis with infliximab

Aims:  To determine what clinical factors relating to efficacy besides complications of orthopedic surgery for patients treated with anti‐tumor necrosis factor (TNF)‐α therapy (infliximab), we analyzed the clinical data of 52 cases of orthopedic surgery, such as total hip arthroplasy (THA), total knee arthroplasty (TKA), total shoulder arthroplasy (TSA), total elbow arthroplasty (TEA), arthroscopic synovectomy, foot arthroplasty, spine surgery, hand surgery and fracture.

Inhibition of MAP kinase in synovium by treatment with tocilizumab in rheumatoid arthritis

To investigate the histological changes of mitogen-activated protein kinase (MAPK) in synovium with tocilizumab in rheumatoid arthritis (RA), synovial tissue samples were assessed from ten methotrexate (MTX)-treated RA patients for control and ten tocilizumab with MTX-treated RA patients. The synovium was observed using hematoxylin and eosin (H&E) stain and analyzed immunohistochemically for the expression of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), matrix metalloproteinase-3 (MMP-3), CD4 (T cell), CD20 (B cell), CD68 (macrophage), vascular endothelial growth factor (VEGF), CD29 (β-1 integrin), phospho-p38 MAPK (Tyr180/Tyr182), phospho-p44/42 MAPK [extracellular signal-regulated kinase (ERK) 1/ERK2], and phospho-c-Jun N-terminal kinase (JNK). H&E staining showed that there is a significant difference of cell proliferation; however, there is no change of hypervascularity in the synovium between both groups. An immunohistochemical examination showed that the decrease of CD29 (β-1 integrin) and JNK was found significant, while ERK was increased in the tocilizumab group. CD20, B-lymphocyte, was decreased in the tocilizumab group compared with the MTX group significantly. IL-6 was completely blocked in the patients who received tocilizumab. TNF-α was similarly expressed in the interstitial cells of synovium of patients in both groups. MMP-3 and CD68 were similarly expressed on the surface of synovium. VEGF was less expressed in both groups. These findings indicate that the inhibition of CD20, CD29, and JNK in MAPK may be involved in the efficacy of tocilizumab compared with MTX treatment in RA.

Histological analysis of synovium in cases of effect attenuation associated with infliximab therapy in rheumatoid arthritis

To investigate the histological changes of synovium in cases of effect attenuation occurring after the use of infliximab in the treatment of rheumatoid arthritis (RA), we histologically assessed synovial tissue from ten methotrexate-treated RA patients and 12 infliximab-treated RA patients after arthroscopic synovectomy. The synovium was observed using hematoxylin and eosin (H&E) stain and analyzed immunohistochemically for expression of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), matrix metalloproteinase-3 (MMP-3), B-cell transmembrane protein, cluster of differentiation 20 (CD20), nuclear factor kappa B (NFkB), bromodeoxyuridine (BrdU), and vascular endothelial growth factor (VEGF). H&E staining showed significant vascular proliferation in the synovium of the RA patients in the infliximab group (p < 0.05). Immunohistochemical examinations showed that TNF-α was completely blocked in patients with effect attenuation who received infliximab (p < 0.05). IL-6 was more strongly expressed in the interstitial cells of synovium of patients who received infliximab than in the cells of patients in the control group (p < 0.05). MMP-3 was expressed on the surface of synovium, and CD20 and BrdU were strongly expressed in the infliximab group compared with the control group (p < 0.05). NFkB was expressed in both groups. VEGF was decreased in the infliximab group compared with control. These findings indicate that the expression pattern of immunohistochemical findings in synovium was changed in effect attenuation cases among RA patients treated with infliximab.

Multiple functions of the von Willebrand Factor A domain in matrilins: secretion, assembly, and proteolysis.

The von Willebrand Factor A (vWF A) domain is one of the most widely distributed structural modules in cell-matrix adhesive molecules such as intergrins and extracellular matrix proteins. Mutations in the vWF A domain of matrilin-3 cause multiple epiphyseal dysplasia (MED), however the pathological mechanism remains to be determined. Previously we showed that the vWF A domain in matrilin-1 mediates formation of a filamentous matrix network through metal-ion dependent adhesion sites in the domain. Here we show two new functions of the vWF A domain in cartilage-specific matrilins (1 and 3). First, vWF A domain regulates oligomerization of matrilins. Insertion of a vWF A domain into matrilin-3 converts the formation of a mixture of matrilin-3 tetramer, trimer, and dimer into a tetramer only, while deletion of a vWF A domain from matrilin-1 converts the formation of the native matrilin-1 trimer into a mixture of trimer and dimer. Second, the vWF A domain protects matrilin-1 from proteolysis. We identified a latent proteolytic site next to the vWF A2 domain in matrilin-1, which is sensitive to the inhibitors of matrix proteases. Deletion of the abutting vWF A domain results in degradation of matrilin-1, presumably by exposing the adjacent proteolytic site. In addition, we also confirmed the vWF A domain is vital for the secretion of matrilin-3. Secretion of the mutant matrilin-3 harbouring a point mutation within the vWF A domain, as occurred in MED patients, is markedly reduced and delayed, resulting from intracellular retention of the mutant matrilin-3. Taken together, our data suggest that different mutations/deletions of the vWF A domain in matrilins may lead to distinct pathological mechanisms due to the multiple functions of the vWF A domain.

Decrease of CD68 and MMP-3 expression in synovium by treatment of adalimumab for rheumatoid arthritis

Aims:  In order to investigate the histological change in the secondary non‐responder cases of adalimumab compared with methotrexate (MTX) treatment, we performed immunohistochemical examination of synovial tissue by seven different molecules to detect expression patterns of cytokines.