Merlin functions as a critical regulator in Staphylococcus aureus-induced osteomyelitis.

Merlin is known as a tumor suppressor, while its role in osteomyelitis remains unclear. This study aimed to investigate the role of Merlin in Staphylococcus aureus-induced osteomyelitis and its underlying mechanisms. S. aureus-induced osteomyelitis mouse model was established in Merlinfl/fl Lyz2cre/+ and Merlinfl/fl Lyz2+/+ mice. Bone marrow-derived macrophages (BMDMs) were isolated and stimulated by lipopolysaccharide (LPS). Bioassays, including quantitative reverse transcription polymerase chain reaction (qRT-PCR), Western blot analysis, and enzyme-linked immunosorbent assays, were conducted to determine the levels of target genes or proteins. Immunoprecipitation was applied to determine the interactions between proteins. DCAF1fl/fl mice were further crossed with Lyz2-Cre mice to establish myeloid cell conditional knockout mice (DCAF1fl/fl Lyz2cre/+ ). It was found that the level of Merlin was elevated in patients with osteomyelitis and S. aureus-infected BMDMs. Merlin deficiency in macrophages suppressed the production of inflammatory cytokines and ameliorated the symptoms of osteomyelitis induced by S. aureus. Merlin deficiency in macrophages also suppressed the production of proinflammatory cytokines in BMDMs induced by LPS. The inhibitory effects of Merlin deficiency on the inflammatory response were associated with DDB1-Cul4-associated factor 1 (DCAF1). In summary, Merlin deficiency ameliorates S. aureus-induced osteomyelitis through the regulation of DCAF1.

Involvement of mechanosensitive ion channels in the effects of mechanical stretch induces osteogenic differentiation in mouse bone marrow mesenchymal stem cells.

Bone marrow mesenchymal stem cells (BMSCs) can be induced to process osteogenic differentiation with appropriate mechanical and/or chemical stimuli. The present study described the successful culture of murine BMSCs under mechanical strain. BMSCs were subjected to 0%, 3%, 8%, 13%, and 18% cyclic tensile strain at 0.5 Hz for 8 hr/day for 3 days. The expression of osteogenic markers and mechanosensitive ion channels was evaluated with real-time reverse transcription-polymerase chain reaction (RT-PCR) and western blot. The expression of alkaline phosphatase (ALP) and matrix mineralization were evaluated with histochemical staining. To investigate the effects of mechanosensitive ion channel expression on cyclic tensile strain-induced osteogenic differentiation, the expression of osteogenic markers was evaluated with real-time RT-PCR in the cells without mechanosensitive ion channel expression. This study revealed a significant augment in osteogenic marker in BMSC strained at 8% compared to other treatments; therefore, an 8% strain was used for further investigations. The ALP expression and matrix mineralization were enhanced in osteogenic induced BMSCs subjected to 8% strain after 7 and 14 days, respectively. Under the same conditions, the osteogenic marker and mechanosensitive ion channel expression were significantly promoted. However, the loss function of mechanosensitive ion channels resulted in the inhibition of osteogenic marker expression. This study demonstrated that strain alone can successfully induce osteogenic differentiation in BMSCs and the expression of mechanosensitive ion channels was involved in the process. The current findings suggest that mechanical stretch could function as efficient stimuli to induce the osteogenic differentiation of BMSCs via the activation of mechanosensitive ion channels.

Treatment of Transverse with or without Posterior Wall Fractures of Acetabulum Using a Modified Smith-Petersen Combined with Kocher-Langenbeck Approach.

BACKGROUND The aim of this study was to explore the surgical treatment of transverse with or without posterior wall fractures of the acetabulum. MATERIAL AND METHODS We surgically treated 21 consecutive cases of pure transverse (7 cases) and with posterior wall (14 cases) fractures of the acetabulum. The anterior column fractures were firstly reduced, temporarily fixed through a modified Smith-Petersen small incision, and finally fixed after the fixation of the posterior column and wall fractures, which were reduced and fixed through a Kocher-Langenbeck approach. The operative time, intra-operative blood loss, quality of reduction (Matta criteria), perioperative complications, osseous union, subsequent complications, and hip function evaluation were recorded. RESULTS The mean operative time was 198.1 min and the mean intra-operative blood loss was 938.1 ml. Anatomic reduction of the anterior column was obtained in 20 cases and was imperfect in 1 case. All posterior column and wall fractures were anatomically reduced. We followed up 18 cases for a mean duration of 16.3 (8-30) months. All the fractures achieved osseous union. The mean Harris score was 85.1 points, with an excellent result in 7 cases, good in 8, fair in 2, and poor in 1. According to modified Merle d' Aubigne and Postel score system, the results were excellent in 2 cases, good in 15, and poor in 1. Avascular necrosis of the femoral head occurred in 1 case, heterotopic ossification in 3 cases, and numbness of the anterolateral thigh in 6 cases. CONCLUSIONS For transverse with or without posterior wall fractures of the acetabulum, reduction and fixation of anterior and posterior column should be done in sequence, and a modified Smith-Petersen small incision might be a good choice in reduction and fixation of the anterior column because it possesses advantages of direct visualization and minimal invasion.

Effects of different surgical techniques on mid-distal humeral shaft vascularity: open reduction and internal fixation versus minimally invasive plate osteosynthesis.

BACKGROUND: Humeral shaft fractures are generally managed with the conventional posterior open reduction and internal fixation (ORIF) or minimally invasive plate osteosynthesis (MIPO). This study was aimed at comparing the outcomes of these surgical techniques in terms of the vascular integrity of the mid-distal humeral shaft. METHODS: Twelve upper limbs were harvested from 6 fresh cadavers. ORIF or MIPO was randomly performed on either side of each pair of limbs. The axillary artery was perfused with a latex-lead tetraoxide red solution to visualize the vascular structures. The vascular integrity of the humerus was examined by plain radiography and dissection. The periosteal filling achieved with each technique was scored and the scores compared. RESULTS: In each limb, one main nutrient artery entering the mid-distal humeral shaft anteromedially (83.3 %) or medially (16.7 %) was first identified. No case of injury to the main nutrient artery was noted for either surgical technique. Injuries to the accessory nutrient arteries entering the mid-distal humeral shaft from the posterior aspect were absent in the MIPO cases, but occurred in 52.9 % of the ORIF cases. In addition, MIPO was also superior to the open plate technique showed superior periosteal filling than. CONCLUSIONS: Our results showed that the MIPO technique is superior to the ORIF in terms of preserving the vascular integrity of the mid-distal humeral shaft.

Ubiquitin-Specific Peptidase 8 Is Critical for the Onset of Infectious Osteomyelitis by Targeting RIPK2 Ubiquitination.

Receptor-interacting serine/threonine kinase (RIPK) is associated with cellular inflammation and immune regulation. The current study explored the role of RIPK2 in osteomyelitis and the potential upstream targets of RIPK2. A Staphylococcus aureus-induced osteomyelitis mouse model was established using wild-type (WT) and ubiquitin-specific peptidase 8 (USP8)-deficient (USP-/-) mice, and the osteomyelitis-related symptoms were evaluated. Bone marrow-derived macrophages (BMDMs) were isolated from the WT and USP-/- mice. Enzyme-linked immunosorbent assays, quantitative polymerase chain reaction, and immunoblot analysis were used to determine the levels of target biomarkers, which were induced by lipopolysaccharide (LPS), CpG, or PAM3CSK4. USP8 promoted RIPK2-mediated NF-κB activation. USP8 is indispensable for RIPK2-mediated LPS-induced NF-κB activation in BMDMs. USP8 is required for the production of inflammatory cytokines induced by LPS, CpG, or PAM3CSK4 in BMDMs. In addition, USP-/- mice exhibited ameliorated symptoms, including less body weight and cortical bone loss, and reduced bacterial load and reactive bone formation in the S. aureus-induced osteomyelitis mouse model. USP8 is critical in the S. aureus-induced osteomyelitis mouse model by targeting RIPK2 ubiquitination.

The Ubiquitination of RIPK2 is Mediated by Peli3 and Negatively Regulates the Onset of Infectious Osteomyelitis.

Osteomyelitis is the infection and destruction of the bone. To date, there is no universal protocol for its treatment. Receptor-interacting serine/threonine-protein kinase 2 (RIPK2) has been implicated in osteomyelitis development. However, the detailed mechanism remains unknown. Here, 6-8w wild-type or Pellino E3 Ubiquitin Protein Ligase Family Member 3 (Peli3)-deficient mice were injected with Staphylococcus aureus to induce osteomyelitis. RAW264.7 cells or bone marrow-derived macrophages isolated from mice were treated with lipopolysaccharide (LPS). Knocking down Peli3 in RAW264.7 cells increased the expression of inflammatory cytokines (interleukin-1ß, interleukin-6, and tumor necrosis factor-α) after LPS stimulation. Inflammation was also activated in S. aureus-induced Peli3-deficient mice. Moreover, S. aureus-infected Peli3-deficient mice also displayed more severe symptoms of osteomyelitis than S. aureus-infected wild-type mice. Moreover, Peli3 targets and degrades RIPK2 through K48-linked ubiquitination, and negatively modulates osteomyelitis by degrading RIPK2. Our data further expands the current understanding of RIPK2 in osteomyelitis, and suggests that RIPK2 might serve as a novel therapeutic target for treating osteomyelitis.

Effects of astragaloside IV on glucocorticoid-induced avascular necrosis of the femoral head via regulating Akt-related pathways.

We investigated the role of astragaloside IV (AS-IV) in preventing glucocorticoid-induced avascular necrosis of the femoral head (ANFH) and the underlying molecular mechanisms. Network pharmacology was used to predict the molecular targets of AS-IV. Molecular dynamic simulations were performed to explore the binding mechanism and interaction mode between AS-IV and Akt. Rat models of glucocorticoid-induced ANFH with AS-IV intervention were established, and osteogenesis, angiogenesis, apoptosis and oxidative stress were evaluated before and after blocking the PI3K/Akt pathway with LY294002. The effects of glucocorticoid and AS-IV on bone marrow mesenchymal stem cells and human umbilical vein endothelial cells incubated with and without LY294002 were determined. Downregulated p-Akt expression could be detected in the femoral heads of glucocorticoid-induced ANFH patients and rats. AS-IV increased trabecular bone integrity and vessel density of the femoral head in the model rats. AS-IV increased Akt phosphorylation and upregulated osteogenesis-, angiogenesis-, apoptosis- and oxidative stress-related proteins and mRNA and downregulated Bax, cleaved caspase-3 and cytochrome c levels. AS-IV promoted human umbilical vein endothelial cell migration, proliferation and tube formation ability; bone marrow mesenchymal stem cell proliferation; and osteogenic differentiation under glucocorticoid influence. AS-IV inhibited apoptosis. LY294002 inhibited these effects. AS-IV prevented glucocorticoid-induced ANFH by promoting osteogenesis and angiogenesis via the Akt/Runx2 and Akt/HIF-1α/VEGF pathways, respectively, and suppressing apoptosis and oxidative stress via the Akt/Bad/Bcl-2 and Akt/Nrf2/HO-1 pathways, respectively.

IL-34 Aggravates Steroid-Induced Osteonecrosis of the Femoral Head via Promoting Osteoclast Differentiation.

IL-34 can promote osteoclast differentiation and activation, which may contribute to steroid-induced osteonecrosis of the femoral head (ONFH). Animal model was constructed in both BALB/c and IL-34 deficient mice to detect the relative expression of inflammation cytokines. Micro-CT was utilized to reveal the internal structure. In vitro differentiated osteoclast was induced by culturing bone marrow-derived macrophages with IL-34 conditioned medium or M-CSF. The relative expression of pro-inflammation cytokines, osteoclast marker genes, and relevant pathways molecules was detected with quantitative real-time RT-PCR, ELISA, and Western blot. Up-regulated IL-34 expression could be detected in the serum of ONFH patients and femoral heads of ONFH mice. IL-34 deficient mice showed the resistance to ONFH induction with the up-regulated trabecular number, trabecular thickness, bone value fraction, and down-regulated trabecular separation. On the other hand, inflammatory cytokines, such as TNF-α, IFN-γ, IL-6, IL-12, IL-2, and IL-17A, showed diminished expression in IL-34 deficient ONFH induced mice. IL-34 alone or works in coordination with M-CSF to promote osteoclastogenesis and activate ERK, STAT3, and non-canonical NF-κB pathways. These data demonstrate that IL-34 can promote the differentiation of osteoclast through ERK, STAT3, and non-canonical NF-κB pathways to aggravate steroid-induced ONFH, and IL-34 can be considered as a treatment target.

miR-146a Protects against Staphylococcus aureus-Induced Osteomyelitis by Regulating Inflammation and Osteogenesis.

Osteomyelitis is a Staphylococcus aureus-caused bone infection. In this study, the effects of miR-146a on osteomyelitis were evaluated. Using the osteoblast cell model and S. aureus-induced osteomyelitis mice model, we monitored the miR-146 expression and explored the effects of miR-146a on cell proliferation of osteoblasts, bone remodeling, osteoclastogenesis, inflammatory cytokine production, and bacterial burden. Upregulated miR-146a was found in mice with S. aureus-induced osteomyelitis. miR-146a attenuated S. aureus-induced cell loss of osteoblasts, rescued the expression of osteogenic markers, altered the bone remodeling, and inhibited inflammatory cytokine production and osteoclastogenesis. miR-146a knockout mice had higher S. aureus burden. In conclusion, miR-146a protects against S. aureus-induced osteomyelitis by regulating inflammation and osteogenesis.

Staphylococcus aureus Infection Initiates Hypoxia-Mediated Transforming Growth Factor-ß1 Upregulation to Trigger Osteomyelitis.

Little is unknown about the regulatory mechanisms underlying the pathogenesis of osteomyelitis induced by Staphylococcus aureus. Hypoxia-inducible factor-1α (HIF-1α) and transforming growth factor ß1 (TGF-ß1) were both upregulated in S. aureus-infected MC3T3-E1 cells and osteomyelitis patients. HIF-1α directly targets the hypoxia-responsive elements (HREs) of TGF-ß1 mRNA to induce its expression. Silencing HIF-1α and TGF-ß1, as well as treatment of hypoxia inhibitor IDF-11774, consistently elevated OPN and RUNX2 expression and alizarin Red S (ARS) and alkaline phosphatase (ALP) staining levels in MC3T3-E1 cells with S. aureus infection. S. aureus infection increased HIF-1α expression and serum TGF-ß1 concentration in a mouse model of osteomyelitis. Hypoxia inhibitor IDF-11774 treatment reduced serum levels of interleukin (IL)-6, IL-1ß, and C-reactive protein. Upon S. aureus infection, hypoxia was activated to trigger TGF-ß1 upregulation through direct targeting of HRE on TGF-ß1 mRNA by HIF-1α, eventually leading to osteomyelitis symptoms in terms of osteogenesis and mineralization deficiencies as well as elevated inflammation. This study hereby suggests a novel signaling cascade involving hypoxia/HIF-1α/TGF-ß1 in osteomyelitis pathogenesis, which could potentially serve as a target for therapeutic measures. IMPORTANCE The pathogenesis of osteomyelitis induced by Staphylococcus aureus remains unclear. To develop therapeutic approaches for osteomyelitis, it is important to understand the molecular mechanisms of its pathogenesis. Our results suggests that hypoxia/HIF-1α/TGF-ß1 signaling is involved in osteomyelitis pathogenesis. Thus, these findings highlight the potential of this signaling components as therapeutic targets for the treatment of osteomyelitis.

Astragaloside IV ameliorates steroid-induced osteonecrosis of the femoral head by repolarizing the phenotype of pro-inflammatory macrophages.

Osteonecrosis of the femoral head (ON-FH) is a common complication of steroid use. Pro-inflammatory macrophages play a crucial role in the apoptosis of osteocytes. The objective of the study was to evaluate a plant extract astragaloside IV (AS-IV) in treating ON-FN. Bone-marrow-derived macrophages (BMDMs) were treated with lipopolysaccharides (LPS), IFN-γ or IL-4 to induce M1 and M2-like phenotypes. Quantitative real-time PCR and Western blot were used to examine M1 and M2 phenotypic markers. Flow cytometry was used to analyze MHC II, CD206, F4/80, and CD11b levels and cell apoptosis. Glucocorticoid was used to induce ON-FN in mice. TNF-α and IL-1ß levels in femoral head were determined using enzyme-linked immunosorbent assay. AS-IV repolarized macrophages from M1 to M2 phenotypes. Culture medium from AS-IV treated M1 macrophages induced less cell apoptosis osteocytes compared to that from untreated M1 macrophages. In ON-FH mice, the ratio of M1 macrophages was decreased in the femoral head by AS-IV, concomitant with a decrease in TNF-α and IL-1ß levels. AS-IV is effective in alleviating ON-FH through its effects in repolarizing macrophages from M1-like phenotype to M2-like phenotype, promoting survival of osteocytes, reducing arthritic symptoms, and decreasing inflammatory cytokines.

Tumor necrosis factor-α promotes Staphylococcus aureus-induced osteomyelitis through downregulating endothelial nitric oxide synthase.

BACKGROUND: Infections of Staphylococcus aureus (S. aureus) often result in osteomyelitis, which is the acute or chronic infections of the bone marrow or bones. TNF-α is long recognized as a key factor contributing to the pathogenesis of osteomyelitis, but little is known about the underlying molecular mechanism. METHODS: Expression levels of TNF-α, and several candidate genes, including endothelial nitric oxide synthase (eNOS), known to be downregulated by TNF-α were analysed in MC3T3-E1 cells with S. aureus infection and osteomyelitis patient blood. MicroRNA(miR)-129-5p was predicted and experimentally verified to target eNOS. Alizarin red sulfate (ARS) and alkaline phosphatase (ALP) staining assays were conducted on MC3T3-E1 cells with S. aureus infection to assess the role of TNF-α/miR-129-5p/eNOS on mineralization defect. RESULTS: TNF-α and miR-129-5p were upregulated while eNOS was downregulated in MC3T3-E1 cells with S. aureus infection and osteomyelitis patients, showing inversely correlated expression profiles. MiR-129-5p directly binds to the 3'-UTR of eNOS mRNA to suppress eNOS expression in MC3T3-E1 cells. TNF-α blocker inhibited miR-129-5p and elevated eNOS expression, likely contributing to rescued mineralization defect in S. aureus-infected MC3T3-E1 cells. During S. aureus infection, upregulated TNF-α increases endogenous miR-129-5p expression, which in turn inhibits eNOS, contributing to osteomyelitis. CONCLUSION: Our study thereby proposes a novel signalling cascade involving TNF-α/miR-129-5p/eNOS in the pathogenesis of osteomyelitis, which may also serve as therapeutic targets.

Bone morphogenetic protein 2 controls steroid-induced osteonecrosis of the femoral head via directly inhibiting interleukin-34 expression.

Increased inflammatory response is one of the major characteristics of osteonecrosis of the femoral head (ONFH). We aimed to investigate the function of bone morphogenetic protein 2 (BMP-2)/interleukin (IL)-34 axis in the inflammatory responses of ONFH. The systemic and local expression of BMPs in ONFH patients was detected by qRT-PCR and ELISA. In vitro osteoclast differentiation and ONFH mouse models, induced by 20 mg/kg methylprednisolone through i.m. injection, were established using WT and BMP-2-/- mice to explore the regulatory role of BMP-2 in pro-inflammatory responses and bone defects of ONFH. IL-34 expression and function were examined in vitro and in vivo through qRT-PCR, tartrate-resistant acid phosphatase (TRAP) staining, and gene knockout. The systemic and local expression of BMPs was elevated in ONFH patients. BMP-2 reduced the production of pro-inflammatory cytokines and inhibited the differentiation of osteoclasts. Mechanistically, BMP-2 inhibited osteoclasts formation through suppressing IL-34 expression and then promoted bone repair and alleviated ONFH. In conclusion, our study reveals that BMP-2 inhibits inflammatory responses and osteoclast formation through downregulating IL-34.

IKKe in osteoclast inhibits the progression of methylprednisolone-induced osteonecrosis.

Previous studies have described that NF-κB signaling mediated by NFκB-inducing kinase (NIK) plays a critical role of the differentiation of osteoclasts. We aim to explore the role of IKKe in methylprednisolone -induced osteonecrosis of the femoral head (ONFH). Methylprednisolone-induced ONFH mice model was successfully established, and subjected to micro computed tomography to detect the femoral head image of the mice. Bone marrow cells from experimental mice were collected and cultured. qPCR and immunoblot were performed to examine the possible signal pathways of IKKe involvement, and osteoclast-related gene expressions in IKKe+/+ and IKKe-/- cells in vitro and in vivo were examined. It was found that the levels of IKKe decreased in ONFH patients, and IKKe interacted with NIK in the NF-κB signal pathway to suppress osteoclasts via inhibiting the transcription of NIK. Furthermore, IKKe knockout promoted the osteoclastogenesis in mice model. Finally, IKKe knockout suppressed methylprednisolone-induced ONFH and pro-inflammatory responses in mice model. Our findings show a mechanism of IKKe inhibition of the progression of methylprednisolone-induced ONFH via the NIK/NF-κB pathway.

Ddb1-Cullin4-Associated-Factor 1 in Macrophages Restricts the Staphylococcus aureus-Induced Osteomyelitis.

INTRODUCTION: Ddb1-cullin4-associated-factor 1 (DCAF1) is known to regulate protein ubiquitination, while the roles of DCAF1 in osteomyelitis remain unknown. This study aims to investigate the effects of DCAF1 deficiency in macrophages on osteomyelitis and elucidate the molecular mechanism. METHODS: Staphylococcus aureus-induced mouse model of osteomyelitis was established on the DCAF1fl/flLyz2cre/+ and DCAF1fl/flLyz2+/+ (control) mice. Flow cytometry was conducted to analyze the populations of adaptive and innate immune cells. Lipopolysaccharides (LPS)-induced bone marrow-derived macrophages (BMDMs) were established. qRT-PCR and immunoblot analysis were used to determine the levels of inflammation-related biomarkers. ELISA was used to determine the release of inflammatory cytokines including IL-1ß, IL-6, and TNF. RESULTS: The populations of immune cells in the bone marrow and spleen were not affected due to DCAF1 deficiency in macrophages. DCAF1 suppressed inflammatory cytokines in LPS-induced BMDMs. Additionally, DCAF1 deficiency in macrophages induced severe symptoms including less bacterial load in the femur, cortical bone loss, and reactive bone formation. Mechanistic study revealed that DCAF1 deficiency induced p38 hyperactivation. DISCUSSION: DCAF1 in macrophages suppressed the Staphylococcus aureus-induced mouse model of osteomyelitis.

MicroRNA-23b-3p participates in steroid-induced osteonecrosis of the femoral head by suppressing ZNF667 expression.

BACKGROUND: Clinical treatment with high-dose of steroid hormone causes steroid-induced osteonecrosis of the femoral head (SONFH), whereas the internal regulation mechanism remains elusive. Numerous studies have reported that microRNAs participated in the development of SONFH through modulating gene expression. The aim of the current study was to clarify the function of microRNA-23b-3p (miR-23b-3p) and ZNF667 in SONFH. EXPERIMENTAL DESIGN: Bioinformatics prediction and luciferase reporter system were utilized to confirm the target relation between miR-23b-3p and ZNF667. To examine the function of miR-23b-3p in vivo, rat SONFH models were established by specific inducers. The morphological changes, plasma viscosity, blood lipid, and inflammatory cytokines were measure by corresponding experiments. RESULTS: MiR-23b-3p and ZNF667 was negatively correlated in SONFH patient tissues, miR-23b-3p was down-regulated, while ZNF667 was up-regulated. MiR-23b-3p targeted ZNF667, the expression level of ZNF667 was suppressed by miR-23b-3p activation whereas strengthened by miR-23b-3p inhibition. SONHF rats with overexpressed miR-23b-3p displayed alleviated symptoms, including reduced plasma viscosity, declined blood lipids, decreased levels of pro-inflammatory cytokines and improved bone integrality. Moreover, elevation of ZNF667 reversed the repression of SONFH induced by miR-23b-3p overexpression. CONCLUSIONS: We found that miR-23b-3p played a protective role in SONFH by targeting ZNF667, which provided a novel reference for SONFH prevention and therapy.

miR-26a Attenuated Bone-Specific Insulin Resistance and Bone Quality in Diabetic Mice.

Diabetes mellitus is a prevalent disease result in several complications, including bone problems. Previous studies have shown that microRNA (miR)-26a regulates glucose metabolism and plays a protective role in diabetes. However, whether miR-26a also affects bone quality in diabetes remains unknown. In the present study, we evaluated the potential effects of miR-26a on bone in diabetic mice. We administrated miR-26a in streptozotocin-induced diabetic mice. The metabolic parameters, bone quality, osteoblast and osteoclast markers, and insulin signaling activation were measured. miR-26a ameliorated insulin resistance and glucose tolerance, improved bone microarchitecture and quality, increased osteoblasts and bone formation, decreased osteoclasts, and promoted the insulin signaling pathway in diabetic mice. These effects were abolished in insulin receptor-compromised Col1a1-Insr+/- mice. In conclusion, miR-26a could ameliorate bone-specific insulin resistance and bone quality in diabetic mice, which depended on the insulin receptors on osteoblasts. Our findings highlight the potential of miR-26a as a therapeutic target for diabetes mellitus-related bone metabolism and diseases.

Open reduction through a posterior incision in the surgical treatment of shoulder posterior dislocation associated with proximal humeral fractures.

BACKGROUND: We explored the surgical technique of reducing the humeral head and repairing the fractures through a combined approach in the treatment of this complex injury. METHODS: Six patients with posterior shoulder dislocations associated with proximal humerus fractures were enrolled in this study. The posteriorly dislocated head was first reduced through a shoulder posterior incision and the ruptured posterior capsular tissues were repaired simultaneously using a suture anchor. The fractures were then reduced and fixed with a PHILOS through a deltopectoral approach. The affected shoulders were immobilized in a neutral position for 6 weeks postoperatively with a customized orthosis and then permitted active shoulder exercises after removal of the orthosis. At the last visit, union of the fractures was evaluated. Degrees of anterior forward of the affected shoulder were recorded. Outcomes were evaluated according to UCLA and Constant criteria. RESULTS: Six patients were followed up for an average of 24.5 ± 7.4 (range 13-35) months. At the last visit, the mean degree of anterior forward was 171.7 ± 7.5 (range 160-180) degrees. An average of 32.9 ± 1.2 (range 31-34) points was obtained according to UCLA criteria, demonstrating excellent and good results in two and four cases, respectively. The mean Constant score was 87.3 ± 4.1 (range 83-92) points. CONCLUSIONS: The dislocated humeral head can be reduced through a posterior approach, while fractures can be reduced and fixed through a deltopectoral approach. This technique has the advantages of simplicity and its minimally invasive approach for reducing the dislocation.

New strategy to rescue the inhibition of osteogenesis of human bone marrow-derived mesenchymal stem cells under oxidative stress: combination of vitamin C and graphene foams.

To rescue the oxidative stress induced inhibition of osteogenesis, vitamin C (VC) was chemically modified onto three-dimensional graphene foams (3D GFs), then their regulation on osteogenesis of human bone marrow-derived mesenchymal stem cells (BM-MSCs) was studied. Combined action of VC + GF significantly decreased H2O2-induced oxidative stress, and rescued H2O2-inhibited cell viability, differentiation and osteogenesis of BM-MSCs in vitro. Further studies revealed that Wnt pathway may be involved in this protection of osteogenesis. Furthermore, an in vivo mouse model of BM-MSCs transplantation showed that VC + GF remarkably rescued oxidative stress inhibited calcium content and bone formation. The combination of VC and GF exhibited more pronounced protective effects against oxidative stress induced inhibition of osteogenesis, compared to monotherapy of VC or GF. Our study proposed a new strategy in stem cell-based therapies for treating bone diseases.

Cordycepin prevents oxidative stress-induced inhibition of osteogenesis.

Oxidative stress is known to be involved in impairment of osteogenesis and age-related osteoporosis. Cordycepin is one of the major bioactive components of Cordyceps militaris that has been shown to exert antioxidant and anti-inflammatory activities. However, there are few reports available regarding the effects of cordycepin on osteogenesis and the underlying mechanism. In this study, we investigated the potential osteoprotective effects of cordycepin and its mechanism systematically using both in vitro model as well as in vivo mouse models. We discovered that hydrogen peroxide (H2O2)-induced inhibition of osteogenesis which was rescued by cordycepin treatment in human bone marrow mesenchymal stem cells (BM-MSCs). Cordycepin exerted its protective effects partially by increasing or decreasing expression of osteogenic and osteoclastogenesis marker genes. Treatment with cordycepin increased Wnt-related genes' expression whereas supplementation of Wnt pathway inhibitor reversed its protective effects. In addition, administration of cordycepin promoted osteogenic differentiation of BM-MSCs by reducing oxidative stress in both ovariectomized and aged animal models. Taken together, these results support the protective effects of cordycepin on oxidative stress induced inhibition of osteogenesis by activation of Wnt pathway.