The effect of intra-articular injection of microRNA-210 on ligament healing in a rat model.

BACKGROUND: It is known from clinical and experimental studies that the healing potential of the anterior cruciate ligament (ACL) is extremely poor and that early phases of ligament healing require an augmented blood supply. MicroRNA (miRNA) is a type of small, noncoding RNA that negatively regulates gene expression, and miRNA (miR)-210 is reported to be crucial for cell response to hypoxia, vascular endothelial growth factor (VEGF)-driven endothelial cell migration, and formation of capillary-like structures. PURPOSE: The purpose of this study was to examine the effect of intra-articular injection of miRNA miR-210 on acceleration of ACL healing. STUDY DESIGN: Controlled laboratory study. METHODS: Two experiments were performed in this study. The ACLs of 12-week-old male LEW/CrlCrlj rats were partially transected. First, the temporal expression change of miR-210 after ACL injury was analyzed using real-time polymerase chain reaction (PCR) on day zero, and 1, 2, and 4 weeks after injury (n = 5 at each time point). Next, intra-articular injection of double-stranded (ds) miR-210 with atelocollagen was performed soon after injury. The control group was injected with control small interfering RNA (siRNA). Four weeks after injection, biomechanical and histological assessments of samples stained with H&E as well as Masson trichrome, and immunohistochemistry for VEGF, fibroblast growth factor 2 (FGF2), isolectin B4, and collagen type I, were performed. Real-time PCR analysis was also performed for quantitative evaluation of miR-210, VEGF-A, and collagen type I. RESULTS: Real-time PCR analysis revealed that miR-210 expression was decreased soon after injury but gradually increased thereafter. Histological analysis confirmed that the transected area was covered with healing tissue in the miR-210 group but remained devoid of any tissue in the control group 4 weeks after injury. Biomechanical analysis confirmed the improvement of biomechanical properties in the miR-210 group; the ultimate failure loads 4 weeks after injection were 30.5 ± 3.1 N in the miR-210 group and 22.8 ± 3.1 N in the control group (P < .05). Real-time PCR analysis showed that endogenous miR-210, VEGF, and collagen type I were highly expressed compared with controls, and immunohistochemistry for VEGF, FGF2, isolectin B4, and collagen type I showed that VEGF and FGF2 were highly upregulated, and there were abundant blood vessels and fibrotic deposition in the miR-210 group. CONCLUSION: Injection of ds miR-210 was effective in promoting the healing of partially torn ACLs through enhancement of angiogenesis via upregulation of VEGF and FGF2. CLINICAL RELEVANCE: It might represent a potential therapeutic approach for treatment of ACL injury.

Angiogenic microRNA-210 is present in cells surrounding osteonecrosis.

A role of microRNAs (miRNAs), which are ≈ 22-nucleotide non-coding RNAs, has recently been recognized in human diseases. The objective of this study was to identify the expression pattern of miRNA (miR)-210, known to be associated with angiogenesis, in bone from patients with osteonecrosis (ON) of the femoral head. The expression of miR-210 in bone from 10 patients with osteoarthritis (OA) of the hip and ten with ON was analyzed by quantitative reverse transcription-polymerase chain reaction (RT-PCR) and by in situ hybridization. In addition, immunohistochemical staining for von Willebrand factor (vWF) and vascular endothelial growth factor (VEGF) was performed to identify the miR-210 expressing cells. We found that in ON samples, the expression of mature, primary miR-210, VEGF, matrix metalloproteinase (MMP)-2, and MMP-7 was significantly higher than that of OA samples. Section in situ hybridization of mature miR-210 revealed that mature miR-210 is expressed around the necrotic area. vWF and VEGF were also strongly expressed in the miR-210 expressing cells. This study shows that miR-210 is intensely expressed in ON, and might play a role in ON pathogenesis. The present study provides a solid basis for further functional analyses of miRNAs in ON.

Mid-term results of acetabular reconstruction using a Kerboull-type acetabular reinforcement device.

PURPOSE: The purpose of this study was to investigate the mid-term results of 32 acetabular reconstructions performed using a Kerboull-type acetabular reinforcement device and bone graft between June 1997 and January 2009. METHODS: The mean age of the patients at the time of surgery was 71.4 years (range 55-85). Patients were followed-up for a mean of 7.5 years (range 2.1-13.7). The acetabular bone defects according to the American Academy of Orthopaedic Surgeons system was type III for 29 hips and type IV for three hips. Bulk allografts were performed in 30 hips and morselised autografts (iliac bone) were performed in two hips. Clinical evaluations were made according to the criteria of Postel/Merle d'Aubigné. RESULTS: The mean pre-operative Postel/Merle d'Aubigné hip score was 7.0 ± 2.9, and the final follow-up hip score was 12.6 ± 2.8. Six hips showed radiographic loosening, and two hips required further revision. A Kaplan-Meier analysis showed that the five-year and ten-year survival rates were 96.9% and 92.3%, respectively, using further revision of the acetabular device as an end point. CONCLUSION: Acetabular reconstruction using a Kerboull-type acetabular reinforcement device and bone graft gives satisfactory mid-term results.

Clinical and radiographical results of 179 thrust plate hip prostheses: 5-14 years follow-up study.

INTRODUCTION: The thrust plate hip prosthesis (TPP) is a bone-reserving prosthesis for cementless fixation at the metaphysis of the proximal femur. We retrospectively evaluated the results of 162 patients (179 hips) who underwent hip arthroplasty using TPP. PATIENTS AND METHODS: Eighty-three patients (87 hips) suffered from osteoarthritis of the hip joint (OA group), 79 patients (92 hips) from osteonecrosis of the femoral head (ON group). The mean age at surgery was 55 years in the OA group and 47.4 years in the ON group. The mean follow-up period was 97 months in the OA group and 104 months in the ON group. For these patients, we evaluated the results clinically and radiographically. RESULTS: The mean Merle d'Aubigne's score improved from 8.2 to 16.9 in the OA group and from 9.1 to 16.6 in the ON group at the final follow-up. Early mechanical loosening of TPP was observed in two hips of OA and one hip of ON. In one patient of ON, bilateral TPPs had to be removed 5 years postoperatively because of infection. Two female patients with ON suffered from a spontaneous femoral fracture below the tip of the lateral plate. Kaplan-Meier survivorship using TPP removed for any reason as the end point was 97.7% in the OA group and 90.3% in the ON group after 13 years. CONCLUSION: The middle-term results of the TPP were satisfactory if the indication for the TPP and the operative procedure were appropriate. The TPP is a useful and safe prosthesis for relatively young patients with not only osteoarthritis of the hip but also osteonecrosis of the femoral head.

A mini-review: microRNA in arthritis.

MicroRNA (miRNA) is a class of noncoding RNA that exhibits tissue- or developmental stage-specific expression patterns and negatively regulates gene expression. MiRNAs play an important role in human diseases, including osteoarthritis (OA) and rheumatoid arthritis (RA). OA is characterized by the progressive destruction of articular cartilage, and several miRNAs exhibit altered expression, playing a role in regulating gene expression in OA pathogenesis, especially in catabolic factors such as matrix metalloproteinases (MMP) and aggrecanases. RA is an autoimmune disease that is characterized by irreversible joint destruction due to chronic synovial inflammation. MiRNAs play an important role in inflammatory response, synovial cell proliferation, and production of MMPs in RA synovial tissues. The expression level of several miRNAs in peripheral blood mononuclear cells correlates with RA disease activity. Recently, therapeutic trials aimed at targeting miRNA in vivo have been conducted. Targeting miRNA will enable a new advanced strategy toward arthritis treatment.

MicroRNA-223 expression in neutrophils in the early phase of secondary damage after spinal cord injury.

MicroRNA (miR)s are short non-coding RNAs that suppress the translation of target genes, and play an important role in gene regulation. Despite this prominence, there are few reports that refer to the expression of miRs after spinal cord injury (SCI). Previously, we reported on miR-223 expression after SCI in mice. The purpose of this study is to reveal the distribution of miR-223 and identify the cells that express miR-223 in the injured spinal cord. Quantitative polymerase chain reaction analysis revealed high expression of miR-223 at 12h after SCI. Double staining of in situ hybridization and immunohistochemistry showed that the signals of miR-223 merged with Gr-1 positive neutrophils. Our data indicate that miR-223 might regulate neutrophils in the early phase after SCI.

Induction of apoptosis in the synovium of mice with autoantibody-mediated arthritis by the intraarticular injection of double-stranded MicroRNA-15a.

OBJECTIVE: MicroRNA is a family of noncoding RNAs that exhibit tissue-specific or developmental stage-specific expression patterns and are associated with human diseases. MicroRNA-15a (miR-15a) is reported to induce cell apoptosis by negatively regulating the expression of Bcl-2, which suppresses the apoptotic processes. The purpose of this study was to investigate whether double-stranded miR-15a administered by intraarticular injection could be taken up by cells and could induce Bcl-2 dysfunction and cell apoptosis in the synovium of arthritic mice in vivo. METHODS: Autoantibody-mediated arthritis was induced in male DBA/1J mice. In the experimental group, double-stranded miR-15a labeled with FAM-atelocollagen complex was injected into the knee joint. In the control group, control small interfering RNA-atelocollagen complex was injected into the knee joint. Synovial expression of miR-15a was analyzed by quantitative polymerase chain reaction, FAM by fluorescence microscopy, Bcl-2 by Western blotting, and Bcl-2 and caspase 3 by immunohistochemistry. RESULTS: The expression of miR-15a in the synovium of the experimental group was significantly higher than that in the control group. Green fluorescence emission of FAM was observed in the synovium of the experimental group. Bcl-2 protein was down-regulated and the expression of caspase 3 was increased as compared with that in the control group. CONCLUSION: These results indicate that the induction of cell apoptosis after intraarticular injection of double-stranded miR-15a occurs through inhibition of the translation of Bcl-2 protein in arthritic synovium.

Expression of MicroRNA-146a in osteoarthritis cartilage.

OBJECTIVE: A role of microRNA, which are approximately 22-nucleotide noncoding RNAs, has recently been recognized in human diseases. The objective of this study was to identify the expression pattern of microRNA-146a (miR-146a) in cartilage from patients with osteoarthritis (OA). METHODS: The expression of miR-146a in cartilage from 15 patients with OA was analyzed by quantitative reverse transcription-polymerase chain reaction (RT-PCR) and by in situ hybridization. Induction of the expression of miR-146a by cultures of normal human articular chondrocytes following stimulation with interleukin-1beta (IL-1beta) was examined by quantitative RT-PCR. RESULTS: All cartilage samples were divided into 3 groups according to a modification of the Mankin score (grade I = mild OA scored 0-5, grade II = moderate OA scored 6-10, and grade III = severe OA scored 11-14). In grade I OA cartilage samples, the expression of miR-146a and COL2A1 was significantly higher than that in the other groups (P < 0.05). In grades II and III OA cartilage, the expression of miR-146a and COL2A1 was decreased, whereas the expression of matrix metalloproteinase 13 (MMP-13) was elevated in grade II OA cartilage. These data showed that miR-146a is expressed intensely in cartilage with a low Mankin grade and that miR-146a expression decreases in parallel with the level of MMP-13 expression. Tissue section in situ hybridization of primary miR-146a (pri-miR-146a) revealed that pri-miR-146a was expressed in chondrocytes residing in all tissue layers, especially in the superficial layer, where it was intensely expressed. The expression of miR-146 was markedly elevated by IL-1beta stimulation in human chondrocytes in vitro. CONCLUSION: This study shows that miR-146 is intensely expressed in low-grade OA cartilage and that its expression is induced by stimulation of IL-1beta. Thus, miR-146 might play a role in OA cartilage pathogenesis.