Limited extension after linked total elbow arthroplasty in patients with rheumatoid arthritis

<p><i>Objective</i>: Total elbow arthroplasty (TEA) has become an established procedure to relieve pain and to increase the range of motion of the destructed elbow in patients with rheumatoid arthritis (RA). However, some patients still have limited extension after TEA, and the causes of limited extension after TEA have yet to be elucidated.</p> <p><i>Methods</i>: To examine whether widening of the joint space can cause such limited extension, we retrospectively analyzed 55 cases of linked TEA in patients with RA. There were seven male and 40 female with a mean age of 63.8 years (range, 30–80 years) and a mean follow-up of 7.5 ± 4.2 years (range, 2.5–15.6 years). The Mayo Elbow Performance Score (MEPS) and radiological measurements were recorded. Widening of the joint space was calculated by subtracting the length measured on postoperative radiograph from preoperative radiograph.</p> <p><i>Results</i>: MEPS and range of motion were significantly improved after surgery except for extension. The degree of extension was significantly correlated with radiological widening of the joint space in the limited extension group. Correlation analyses showed that postoperative limited extension was correlated with lower MEPS daily function.</p> <p><i>Conclusions</i>: Limited extension after linked TEA is partly derived from perioperative widening of the joint space and potentially limits daily function in patients with RA.</p

Plasma sLOX-1 is a potent biomarker of clinical remission and disease activity in patients with seropositive RA

<p><i>Objectives</i>: Soluble lectin-like oxidized low-density lipoprotein receptor 1 (sLOX-1) is present in the circulation and synovial fluid in patients with rheumatoid arthritis (RA). The aim of this study was to assess whether sLOX-1 level is associated with clinical remission and disease activity in patients with RA.</p> <p><i>Methods</i>: Clinical and laboratory data were analyzed for 282 patients with RA. Plasma sLOX-1 level was measured by enzyme-linked immunosorbent assay (ELISA). The remission status and sLOX-1 levels were compared between four groups of patients based on the positivity of rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPAs). Relationships between sLOX-1 level and the 28-joint Disease Activity Score with erythrocyte sedimentation rate (DAS28-ESR) were analyzed by multivariate logistic regression.</p> <p><i>Results</i>: The patients in the RF + ACPA + group tended to exhibit higher sLOX-1 levels when compared to the other three groups. In the RF + ACPA + group, the sLOX-1 level was significantly higher in the non-remission group than in the remission group, irrespective of treatment. Multivariate logistic regression showed significant correlations between sLOX-1 level and DAS28-ESR.</p> <p><i>Conclusions</i>: sLOX-1 level might be a useful biomarker for assessing clinical remission and disease activity in double-positive RA patients.</p

TNFα, PDGF, and TGFβ synergistically induce synovial lining hyperplasia via inducible PI3Kδ

<p><i>Objectives.</i> To determine the mechanism underlying hypertrophic synovium in rheumatoid arthritis (RA).</p> <p><i>Methods.</i> We examined micromass cultures of fibroblast-like synoviocytes (FLSs) stimulated with tumor necrosis factor α (TNFα), platelet-derived growth factor (PDGF), and/or transforming growth factor β (TGFβ). The hypertrophic architecture of the micromasses, expression of phosphoinositide 3 kinase (PI3K) isoforms, and persistent activation of PI3K-Akt pathways were investigated. FLSs transfected with siRNA were also examined in the micromass cultures.</p> <p><i>Results.</i> The combination of TNFα, PDGF, and TGFβ (TPT condition) induced obvious hypertrophic architecture of the intimal lining layer in FLSs in micromass cultures, and was accompanied by upregulated expression of matrix metalloproteinase-3 (MMP3), Cadherin-11, and PI3Kδ. In monolayer FLSs, the TPT condition enhanced the expression of PI3Kδ and persistent activation of the PI3K-Akt pathway. Knockdown of PI3Kδ significantly inhibited the formation of the hypertrophic synovial lining in the TPT condition.</p> <p><i>Conclusions.</i> These results collectively indicate that inducible PI3Kδ plays a crucial role in persistent activation of PI3K-Akt in FLSs, and in the formation of a hypertrophic synovial lining. PI3Kδ may be an alternative treatment target for the regulation of proliferative synovium in RA.</p

MCP/CCR2 Signaling Is Essential for Recruitment of Mesenchymal Progenitor Cells during the Early Phase of Fracture Healing

<div><p>Objective</p><p>The purpose of this study was to investigate chemokine profiles and their functional roles in the early phase of fracture healing in mouse models.</p><p>Methods</p><p>The expression profiles of chemokines were examined during fracture healing in wild-type (WT) mice using a polymerase chain reaction array and histological staining. The functional effect of monocyte chemotactic protein-1 (MCP-1) on primary mouse bone marrow stromal cells (mBMSCs) was evaluated using an <i>in vitro</i> migration assay. MCP-1^−/− and C-C chemokine receptor 2 (CCR2)^−/− mice were fractured and evaluated by histological staining and micro-computed tomography (micro-CT). RS102895, an antagonist of CCR2, was continuously administered in WT mice before or after rib fracture and evaluated by histological staining and micro-CT. Bone graft exchange models were created in WT and MCP-1^−/− mice and were evaluated by histological staining and micro-CT.</p><p>Results</p><p><i>MCP-1</i> and <i>MCP-3</i> expression in the early phase of fracture healing were up-regulated, and high levels of MCP-1 and MCP-3 protein expression observed in the periosteum and endosteum in the same period. MCP-1, but not MCP-3, increased migration of mBMSCs in a dose-dependent manner. Fracture healing in MCP-1^−/− and CCR2^−/− mice was delayed compared with WT mice on day 21. Administration of RS102895 in the early, but not in the late phase, caused delayed fracture healing. Transplantation of WT-derived graft into host MCP-1^−/− mice significantly increased new bone formation in the bone graft exchange models. Furthermore, marked induction of MCP-1 expression in the periosteum and endosteum was observed around the WT-derived graft in the host MCP-1^−/− mouse. Conversely, transplantation of MCP-1^−/− mouse-derived grafts into host WT mice markedly decreased new bone formation.</p><p>Conclusions</p><p>MCP-1/CCR2 signaling in the periosteum and endosteum is essential for the recruitment of mesenchymal progenitor cells in the early phase of fracture healing.</p></div

Immunohistochemical analysis of WT rib fracture on day 3.

<p>A, B, Protein expression levels of MCP-1 (<b>A</b>) and MCP-3 (<b>B</b>) were identified at the periosteum and endosteum on day 3. <b>C</b>, CCR2-positive cells were predominantly found within the bone marrow and surrounding tissues on day 3. Original magnification, 40×. Middle panel, high-magnification views (original magnification, 200×). The result is representative of three separate experiments.</p

MCP-1^−/− and CCR2^−/− mice displayed delayed fracture healing <i>in vivo</i>.

<p><b>A</b>: Histology of the fracture callus stained by hematoxylin-eosin/alcian-blue staining on day 21. <b>B</b>: Representative 3D micro-CT image of a fractured rib on day 21. <b>C</b>: Newly formed callus volume in the MCP-1^−/− and CCR2^−/− mice on day 21 was quantified using micro-CT.</p

Comprehensive microRNA Analysis Identifies miR-24 and miR-125a-5p as Plasma Biomarkers for Rheumatoid Arthritis

<div><p>MicroRNAs (miRNAs) are present in human plasma and known as a non-invasive biomarker for cancer detection. Our study was designed to identify plasma miRNAs specific for rheumatoid arthritis (RA) by a comprehensive array approach. We performed a systematic, array-based miRNA analysis on plasma samples from three RA patients and three healthy controls (HCs). Plasma miRNAs with more than four times change or with significant (<i>P</i><0.05) change in expression, or detectable only in RA plasma, were confirmed with plasma from eight RA patients and eight HCs using real-time quantitative PCR. Consistently detectable miRNAs that were significantly different between RA patients and HCs were chosen for further validation with 102 RA patients and 104 HCs. The area under curves (AUC) were calculated after plotting the receiver operating characteristic (ROC) curves. To determine if these miRNAs are specific for RA, the concentrations of these miRNAs were analyzed in 24 patients with osteoarthritis (OA), and 11 patients with systemic lupus erythematosus (SLE). The array analysis and the subsequent confirmation in larger patient cohort identified significant alterations in plasma levels of seven miRNAs. The highest AUC was found for miR-125a-5p, followed in order by miR-24 and miR-26a. Multivariable logistic regression analysis showed that miR-24, miR-30a-5p, and miR-125a-5p were crucial factors for making detection model of RA and provided a formula for <i>E</i>stimated <i>P</i>robability of <i>RA</i> by plasma <i>M</i>iRNA (ePRAM), employing miR-24, miR-30a-5p and miR-125a-5p, which showed increased diagnostic accuracy (AUC: 0.89). The level of miR-24, miR-125a-5p, and ePRAM in OA and SLE patients were lower than that in RA. There was no significant difference in detection for anti-citrullinated protein antibody (ACPA)-positive and ACPA-negative RA patients. These results suggest that the plasma concentrations of miR-24 and miR-125a-5p, and ePRAM are potential diagnostic markers of RA even if patients were ACPA-negative.</p></div

Blockade of CCR2 in the early phase displayed delayed fracture healing <i>in vivo</i>.

<p><b>A</b>: WT mice received continuous administration of CCR2 antagonist, RS102895, or DMSO (controls) until day 12, beginning 2 days before or 4 days after rib fracture. In the control group, DMSO was administered as a control for 14 days. Representative micro-CT image of a fractured rib on day 21. <b>B</b>: Newly formed callus volume on day 21 in the pre-treatment or post-treatment group was quantified using micro-CT. <b>C</b>: Histology of the fracture callus stained by hematoxylin-eosin/alcian-blue staining on day 7.</p

A flowchart illustrates how we analyzed plasma miRNAs.

<p>We performed a systematic, array-based miRNA analysis on plasma samples from three rheumatoid arthritis (RA) patients and three healthy controls (HCs). Plasma miRNAs with more than four times change or with significant (P<0.05) change in expression, or detectable only in RA plasma, were confirmed with plasma from eight RA patients and eight HCs using real-time quantitative PCR (qRT-PCR). Eleven differently expressed miRNAs and one normalizer miRNA (miR-30a-5p) were chosen for further validation with 102 RA patients and 104 HCs. The concentrations of two specific miRNAs and one normalizer miRNA were measured in 24 patients with osteoarthritis (OA), and 11 patients with systemic lupus erythematosus (SLE). We also tried to find out miRNA that could be used for normalizer with geNorm and NormFinder using the results of microarray. miR-30a-5p was a candidate normalizer.</p

Evaluation of candidate miRNAs.

<p><b>A:</b> Clinical features of patients with OA and SLE who contributed plasma. <b>B:</b> Plasma concentrations of miR-24, miR-125a-5p, and ePRAM in patients with osteoarthritis (OA) and systemic lupus arthritis (SLE). The green areas indicate the ranges in which patients are diagnosed as RA positive. <b>C:</b> Histogram of plasma concentrations of each miRNA in anti-citrullinated protein antibody (ACPA)-negative RA patients, ACPA-positive RA patients, and HCs. The green panels indicate the cutoff value. <b>D:</b> Sensitivity of each miRNA test in ACPA-positive and ACPA-negative RA patients. Data are shown as mean ± standard deviation. SLEDAI = SLE Disease Activity Index.</p