Objective. A role of microRNA, which are ϳ22-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-1␤ (IL-1␤) 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-1␤ 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-1␤. Thus, miR-146 might play a role in OA cartilage pathogenesis.Osteoarthritis (OA) is a highly prevalent disease that is characterized by progressive degeneration of articular cartilage (1-4). Although little is known about the pathogenesis of OA, an imbalance between anabolic and catabolic factors that maintain the homeostasis of cartilage is thought to lead to cartilage degradation. While there is a delicate balance between anabolism and catabolism in the strict regulation of matrix turnover in normal cartilage, catabolism becomes dominant over anabolism in OA cartilage, leading to the degradation of cartilage. Several studies have demonstrated an interaction between anabolic factors, such as transforming growth factor ␤, and catabolic factors, such as matrix metalloproteinases (MMPs) and aggrecanases, in chondrocytes; however, the molecular mechanisms involved in OA remain unclear (5).MicroRNA (miRNA) are a family of ϳ22-nucleotide noncoding RNAs identified in organisms ranging from nematodes to humans (6-8). Many miRNA are evolutionarily conserved across phyla, regulating gene expression by posttranscriptional gene repression. The miRNA regulate gene expression by binding the 3Ј-untranslated region of...

The management of patellar dislocation syndrome has traditionally been difficult. There are no golden standard methods for patellar dislocations probably due to the many etiologies. However, it is known that medial patellofemoral ligament (MPFL) is damaged when the patella is dislocated. The purpose of this study is to examine whether our method of MPFL reconstruction is useful for the treatment of dislocated patellae and unstable patellae. Forty-six knees (43 patients) of 68 knees (65 patients) that were operated on using our surgical procedure for MPFL reconstruction with the advancement of the vastus medialis or the MPFL reconstruction with Insall's procedure were followed up for at least 5 years. The patient age ranged from 6 to 43 years. These knees consisted of six habitual dislocation patellae, twenty-six recurrent dislocation patellae, ten traumatic dislocation patellae, and four unstable patellae. The patients were evaluated pre-operatively and more than three times post-operatively at 6, 12, 36, 60, or 120 months. No patient experienced patellar dislocation after surgery. Their post-operative Kujala's scores were significantly improved. On conventional X-ray and on stress X-ray evaluations, the mean values for congruence angle, tilting angle, lateral shift ratio, medial stress shift ratio, and lateral stress shift ratio at the final follow-up (60 or 120 months) were demonstrated to be within the normal range. We conclude that our MPFL reconstruction method with the advancement of the vastus medialis or with Insall's procedure might be recommended for the treatment of habitual, recurrent, and indeed any other type of patellar dislocation, as well as for unstable patellae.

BackgroundInterleukin (IL)-17 is an important factor in rheumatoid arthritis (RA) pathogenesis. MicroRNA (miRNA)s are a family of non coding RNAs and associated with human diseases including RA. The purpose of this study is to identify the miRNAs in the differentiation of IL-17 producing cells, and analyze their expression pattern in the peripheral blood mononuclear cells (PBMC) and synovium from RA patients.MethodsIL-17 producing cells were expanded from CD4+T cell. MiRNA microarray was performed to identify the miRNAs in the differentiation of IL-17 producing cells. Quantitative polymerase chain reaction was performed to examine the expression patterns of the identified miRNAs in the PBMC and synovium from RA and osteoarthritis (OA) patients. Double staining combining in situ hybridization and immunohistochemistry of IL-17 was performed to analyze the expression pattern of identified miRNA in the synovium.ResultsSix miRNAs, let-7a, miR-26, miR-146a/b, miR-150, and miR-155 were significantly up regulated in the IL-17 producing T cells. The expression of miR-146a and IL-17 was higher than in PBMC in the patients with low score of Larsen grade and short disease duration. MiR-146a intensely expressed in RA synovium in comparison to OA. MiR-146a expressed intensely in the synovium with hyperplasia and high expression of IL-17 from the patients with high disease activity. Double staining revealed that miR-146a expressed in IL-17 expressing cells.ConclusionThese results indicated that miR-146a was associated with IL-17 expression in the PBMC and synovium in RA patients. There is the possibility that miR-146a participates in the IL-17 expression.

The purpose of present study was to evaluate active mobilization effect of mesenchymal stem cells (MSCs) into injured tissues after intraarticular injection of MSCs, and to evaluate their contribution to tissue regeneration. MSCs, which were obtained from green fluorescent protein (GFP) transgenic Sprague-Dawley (SD) rat and cultivated, were injected into normal SD rats in which multiple tissues had been injured including anterior cruciate ligament (ACL), medial meniscus, and articular cartilage of the femoral condyles. At 4 weeks after injection of MSCs, fluorescent microscopic observation, immunohistochemical or histological examinations were performed to evaluate mobilization of MSCs into injured tissue and their contribution to tissue regeneration. In the group of 1 x 10(6) MSCs injection, GFP positive cells could mobilize into the injured ACL alone in all 8 knees. In the group of 1 x 10(7) MSCs injection, GFP positive cells were observed in the injured site of ACL in all 8 knees and in the injured site of medial meniscus and cartilage of femoral condyles in 6 of 8 knees. More interestingly, extracellular matrix stained by toluidine blue was present around GFP positive cells in the injured femoral condyles cartilage and medial meniscus, indicating tissue regeneration. Intraarticularly injected MSCs could mobilize into the injured tissues, and probably contributed to tissue regeneration. This study demonstrated the possibility of intraarticular injection of MSCs for the treatment of intraarticular tissue injuries including ACL, meniscus, or cartilage. If this treatment option is established, it can be minimally invasive compared to conventional surgeries for these tissues.

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We present a new surgical technique of anterior cruciate ligament (ACL) augmentation using autogenous hamstring tendons or allogenic fascia lata under arthroscopy for patients in whom considerable ACL remnants with mechanoreceptors are preserved. We review the clinical results of 40 patients who underwent this ACL augmentation, as assessed by manual instability tests, KT-2000 knee arthrometer, Lysholm and Gillquist score, joint position sense and magnetic resonance imaging (MRI), and compare them with those of ACL reconstruction. The side-to-side differences of anterior displacement measured by the KT-2000 knee arthrometer at 30 lbs, an average of 5.3 +/- 2.6 mm preoperatively, was significantly improved to an average of 0.7 +/- 1.8 mm in the augmentation group, while an average of 6.0 +/- 2.4 mm was improved to 1.8 +/- 2.1 mm in the reconstruction group. There was no statistically significant difference between the preoperative values in the two groups, but the postoperative values of the augmentation group were significantly less than those of the reconstruction group. The ratio of anterior terminal stiffness of the augmentation group was 1.2 +/- 1.8, and that of the ACL reconstruction group was 0.7 +/- 0.4. This was a statistically significant difference (P < 0.05). Thus, as for the KT-2000 knee arthrometer, the ACL augmentation group showed significantly better anteroposterior stability and terminal stiffness than the ACL reconstruction group. The final inaccuracy of joint position sense of the augmentation group was 0.7 degrees +/- 0.7 degrees, while that of the reconstruction group was 1.7 degrees +/- 1.2 degrees indicating a significant difference (P < 0.05). This study demonstrates that ACL augmentation, which can preserve ACL remnants with mechanoreceptors, is superior to ACL reconstruction from the viewpoint of position sense and joint stability.

Skeletal muscle is able to repair itself through regeneration. However, an injured muscle often does not fully recover its strength because complete muscle regeneration is hindered by the development of fibrosis. Biological approaches to improve muscle healing by enhancing muscle regeneration and reducing the formation of fibrosis are being investigated. Previously, we have determined that insulin-like growth factor-1 (IGF-1) can improve muscle regeneration in injured muscle. We also have investigated the use of an antifibrotic agent, decorin, to reduce muscle fibrosis following injury. The aim of this study was to combine these two therapeutic methods in an attempt to develop a new biological approach to promote efficient healing and recovery of strength after muscle injuries. Our findings indicate that further improvement in the healing of muscle lacerations is attained histologically by the combined administration of IGF-1 to enhance muscle regeneration and decorin to reduce the formation of fibrosis. This improvement was not associated with improved responses to physiological testing, at least at the time-points tested in this study. There are various types of muscle injury, including those that occur through direct trauma (e.g., laceration and contusion) and those attributable to indirect damage (e.g., ischemia, denervation, and strain), but the general process of muscle damage and repair is similar in most cases. 2,10,12,19 -21,24 -26 Muscle fibers have the ability to regenerate following injury through the activation of satellite cells, 13 but the healing process is very slow and often results in incomplete recovery of strength due to the development of scar tissue. 12,24,25 The muscle healing process comprises several phases, including degeneration and inflammation, regeneration, and scar formation (after severe muscle injury). 12,24 Muscle regeneration occurs early in this process; it begins about 1 week after injury, peaks during the 2nd week, and then rapidly declines. 3,12,16,20,24,25 We have shown previously that growth factors, including insulin-like growth factor-1 (IGF-1), basic-fibroblast growth factor (bFGF), and nerve growth factor (NGF), can improve muscle regeneration during this preliminary phase of healing. 19 -21,26 Of these growth factors, IGF-1 was found to have the greatest effect on the healing of the injured muscle by increasing both the efficiency of muscle regeneration and muscle strength. However, none of the growth factors that have been investigated appears able to completely heal injured muscle, possibly due to the development of muscle fibrosis.The development of fibrosis begins 2 weeks after muscle injury and continues over time. This process hinders muscle regeneration and prevents full strength recovery in the injured skeletal muscle. 2,3,12,24,25 We have reported that myogenic cells can differentiate into myofibroblasts upon muscle Abbreviations: ECM, extracellular matrix; bFGF, basic-fibroblast growth factor; GM, gastrocnemius muscle; H&E, hematoxylin and eo...

MicroRNA (miRNA)s are a class of non-coding RNAs that regulate gene expression post-transcriptionally. Muscle-specific miRNA, miRNA (miR)-1, miR-133 and miR-206 play a crucial role in the regulation of muscle development and homeostasis. Muscle injuries are a common muscloskeletal disorder, and the most effective treatment has not been established yet. The purpose of this study was to demonstrate that a local injection of double-stranded (ds) miR-1, miR-133 and 206 can accelerate muscle regeneration in a rat skeletal muscle injury model. After the laceration of the rat tibialis anterior muscle, ds miR-1, 133 and 206 mixture mediated atelocollagen was injected into the injured site. The control group was injected with control siRNA. At 1 week after injury, an injection of miRNAs could enhance muscle regeneration morphologically and physiologically, and prevent fibrosis effectively compared to the control siRNA. Administration of exogenous miR-1, 133 and 206 can induce expression of myogenic markers, MyoD1, myogenin and Pax7 in mRNA and expression in the protein level at 3 and 7 days after injury. The combination of miR-1, 133 and 206 can promote myotube differentiation, and the expression of MyoD1, myogenin and Pax7 were up-regulated in C2C12 cells in vitro. Local injection of miR-1, 133 and 206 could be a novel therapeutic strategy in the treatment of skeletal muscle injury.