MicroRNA-497 elevation or LRG1 knockdown promotes osteoblast proliferation and collagen synthesis in osteoporosis via TGF-ß1/Smads signalling pathway.

MicroRNAs (miRNAs) have been corroborated to engage in the process of cellular activities in osteoporosis. However, few researches have been conducted to expose the integrated role of miR-497, leucine-rich alpha-2-glycoprotein-1 (LRG1) and transforming growth factor beta 1 (TGF-ß1)/Smads signalling pathway in osteoporosis. Thereafter, the study is set out to delve into miR-497/LRG1/TGF-ß1/Smads signalling pathway axis in osteoporosis. Osteoporosis bone tissues and normal bone tissues were collected. Rat osteoporosis models were constructed via ovariectomy. Model rats were injected with restored miR-497 or depleted LRG1 to explore their roles in osteoporosis. Rat osteoblasts were extracted from osteoporosis rats and transfected with restored miR-497 or depleted LRG1 for further verification. MiR-497 and LRG1 expression in femoral head tissues and osteoblasts of osteoporosis rats were detected. TGF-ß1/Smads signalling pathway-related factors were detected. MiR-497 was poorly expressed while LRG1 was highly expressed and TGF-ß1/Smads signalling pathway activation was inhibited in osteoporosis. MiR-497 up-regulation or LRG1 down-regulation activated TGF-ß1/Smads signalling pathway, promoted collagen type 1 synthesis and suppressed oxidative stress in femoral head tissues in osteoporosis. MiR-497 restoration or LRG1 knockdown activated TGF-ß1/Smads signalling pathway, promoted viability and suppressed apoptosis of osteoblasts in osteoporosis. Our study suggests that miR-497 up-regulation or LRG1 down-regulation promotes osteoblast viability and collagen synthesis via activating TGF-ß1/Smads signalling pathway, which may provide a novel reference for osteoporosis treatment.

Blocking PI3K/AKT signaling inhibits bone sclerosis in subchondral bone and attenuates post-traumatic osteoarthritis.

PI3K/AKT signaling is essential in regulating pathophysiology of osteoarthritis (OA). However, its potential modulatory role in early OA progression has not been investigated yet. Here, a mouse destabilization OA model in the tibia was used to investigate roles of PI3K/AKT signaling in the early subchondral bone changes and OA pathological process. We revealed a significant increase in PI3K/AKT signaling activation which was associated with aberrant bone formation in tibial subchondral bone following destabilizing the medial meniscus (DMM), which was effectively prevented by treatment with PI3K/AKT signaling inhibitor LY294002. PI3K/AKT signaling inhibition attenuated articular cartilage degeneration. Serum and bone biochemical analyses revealed increased levels of MMP-13, which was found expressed mainly by osteoblastic cells in subchondral bone. However, this MMP-13 induction was attenuated by LY294002 treatment. Furthermore, PI3K/AKT signaling was found to enhance preosteoblast proliferation, differentiation, and expression of MMP-13 by activating NF-κB pathway. In conclusion, inhibition of PI3K/AKT/NF-κB axis was able to prevent aberrant bone formation and attenuate cartilage degeneration in OA mice.

Quercetin reduces neural tissue damage and promotes astrocyte activation after spinal cord injury in rats.

Spinal cord injury (SCI) is lead to locomotor impairment because of neurological damage after following trauma. Quercetin (Que) has been confirmed to have a neuro-protective effect during nerve damage processes. The purpose of this study was to determine the roles of Que in functional recovery, cavity formation, astrocyte activation, and nerve regeneration following SCI. Sprague-Dawley rats were randomly divided into three groups: Sham group, SCI group, and Que + SCI group. A rat model of SCI was made at T10 using the modified Allen's method. In the Que + SCI group, animals underwent laminectomy and were then intraperitoneally injected with 20 mg/kg Que for 7 days. Locomotor function was determined with the Basso, Beattie, Bresnahan (BBB) scores at 1, 3, 5, and 7 days post-injury. At 7 days post-injury, somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) were recorded. Hematoxylin-Eosin (HE) staining was used to investigate cavity formation. Astrocyte activation was assayed by immunohistochemistry staining with an antibody specific for glial fibrillary acidic protein (GFAP), as well as the expression of GFAP and S100ß. Axons were stained using an antibody specific for neurofilament 200 (NF200) and 5-hydroxytryptamine (5-HT). In addition, the protein level of BDNF, p-JNK2, and p-STAT3 was detected using Western blot. Que promoted locomotor function and electrophysiological recovery, reduced cavity formation, contributed to astrocyte activation and axonal regeneration after acute SCI. Moreover, Que up-regulated the expression of BDNF, but reduced p-JNK2 and p-STAT3 expression after acute SCI. Taken together, Que promoted locomotor and electrophysiological functional recovery, astrocyte activation and axonal regeneration after acute SCI, possibly through BDNF and JAK2/STAT3 signaling pathways.

Synovial macrophage M1 polarisation exacerbates experimental osteoarthritis partially through R-spondin-2.

OBJECTIVES: To investigate the roles and regulatory mechanisms of synovial macrophages and their polarisation in the development of osteoarthritis (OA). METHODS: Synovial tissues from normal patients and patients with OA were collected. M1 or M2-polarised macrophages in synovial tissues of patients with OA and OA mice were analysed by immunofluorescence and immunohistochemical staining. Mice with tuberous sclerosis complex 1 (TSC1) or Rheb deletion specifically in the myeloid lineage were generated and subjected to intra-articular injection of collagenase (collagenase-induced osteoarthritis, CIOA) and destabilisation of the medial meniscus (DMM) surgery to induce OA. Cartilage damage and osteophyte size were measured by Osteoarthritis Research Society International score and micro-CT, respectively. mRNA sequencing was performed in M1 and control macrophages. Mice and ATDC5 cells were treated with R-spondin-2 (Rspo2) or anti-Rspo2 to investigate the role of Rspo2 in OA. RESULTS: M1 but not M2-polarised macrophages accumulated in human and mouse OA synovial tissue. TSC1 deletion in the myeloid lineage constitutively activated mechanistic target of rapamycin complex 1 (mTORC1), increased M1 polarisation in synovial macrophages and exacerbated experimental OA in both CIOA and DMM models, while Rheb deletion inhibited mTORC1, enhanced M2 polarisation and alleviated CIOA in mice. The results show that promoting the macrophage M1 polarisation leads to exacerbation of experimental OA partially through secretion of Rspo2 and activation of ß-catenin signalling in chondrocytes. CONCLUSIONS: Synovial macrophage M1 polarisation exacerbates experimental CIOA partially through Rspo2. M1 macrophages and Rspo2 are potential therapeutic targets for OA treatment.

Designation and Validation of a Posterior Anatomical Plate for the Anterior Column of the Acetabulum.

BACKGROUND Surgical treatment of acetabular fractures is one of the greatest challenges for orthopedic surgeons. Fixation of most displaced fractures requires extensive exposure, which may lead to complications, including blood loss, neural or vascular injury, postoperative infection, wound healing problems, and heterotopic bone formation. MATERIAL AND METHODS This study was conducted to certify an anatomic plate with an anterior column lag screw guiding device to repair the posterior acetabulum. Complete pelvic spiral computed tomography (CT) scan data were collected from 56 patients. The posterior column of the acetabulum was simulated with a lag screw. The guiding device for the plate was designed by measuring the position of the screw point and the direction and maximum diameter of the screw. RESULTS The distance from the screw point to the apex of the greater sciatic notch was farther in women than in men. The distance from the screw point to the ischial spine was also farther in women than in men. The q angle (front inclination angle) of the screw was lower in women than in men. The j angle (camber screw angle) was greater in women than in men. The success rate when using the guided device was significantly higher than when using traditional pedicle screws. CONCLUSIONS The guided device was very useful for improving placement success and accuracy rates of the acetabular posterior anatomical anterior column plate using antegrade lag screws, and for reducing surgical risk and injury.

Myostatin serum concentrations are correlated with the severity of knee osteoarthritis.

OBJECTIVE: Myostatin, a member of the transforming growth factor-ß family, contributes to joint deterioration in mice. Thus, we aimed to assess the correlation of myostatin concentrations with the presence and severity of knee osteoarthritis (OA). MATERIAL AND METHODS: We determined serum and synovial fluid (SF) myostatin concentrations in a population of 184 patients with knee OA and 109 healthy controls. RESULTS: The knee OA group presented with higher serum myostatin concentrations than the controls. Knee OA patients with KL grade 4 showed higher serum and SF myostatin concentrations compared with those with KL grade 2 and 3. Knee OA patients with KL grade 3 had higher serum and SF myostatin concentrations compared with those with KL grade 2. Serum and SF myostatin concentrations were significantly correlated with KL grading. CONCLUSION: Serum and SF myostatin concentrations were correlated with the presence and severity of knee OA.

Forsythiaside A Exhibits Anti-inflammatory Effects in LPS-Stimulated BV2 Microglia Cells Through Activation of Nrf2/HO-1 Signaling Pathway.

Inflammation and oxidative stress have been reported to play critical roles in the pathogenesis of neurodegenerative disease. Forsythiaside A, a phenylethanoside product isolated from air-dried fruits of Forsythia suspensa, has been reported to have anti-inflammatory and antioxidant effects. In this study, the anti-inflammatory effects of forsythiaside A on LPS-stimulated BV2 microglia cells and primary microglia cells were investigated. The production of inflammatory mediators TNF-α, IL-1ß, NO and PGE2 were detected in this study. NF-κB, nuclear factor-erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) expression were detected by western blot analysis. Our results showed that forsythiaside A significantly inhibited LPS-induced inflammatory mediators TNF-α, IL-1ß, NO and PGE2 production. LPS-induced NF-κB activation was suppressed by forsythiaside A. Furthermore, forsythiaside A was found to up-regulate the expression of Nrf2 and HO-1. In conclusion, this study demonstrates that forsythiaside A inhibits LPS-induced inflammatory responses in BV2 microglia cells and primary microglia cells through inhibition of NF-κB activation and activation of Nrf2/HO-1 signaling pathway.

Anterograde Fixation Module for Posterior Acetabular Column Fracture: Computer-Assisted Determination of Optimal Entry Point, Angle, and Length for Screw Insertion.

BACKGROUND The aim of this study was to provide valid data for a plate-screw fixation model for fractured posterior-anterior columns of the acetabulum. MATERIAL AND METHODS Nineteen cadaveric bony hemi-pelvis specimens were obtained and 50 healthy adults were enrolled. The modified Stoppa approach and computed tomography (CT) imaging were used to collect the measured parameter data of the module. RESULTS The measured parameter data were as follows: OP, 0.96±0.32 cm in females and 0.92±0.16 cm in males (P>0.05); PI, 0.98±0.28 cm in females, and 0.75±0.23 cm in males (P>0.05); ÐÏ´, 59.68°±6.28° in females and 56.75°±3.22° in males (P>0.05); and Ðφ, 41.27°±2.76° in females and 34.31°±2.78° in males (P<0.05). The corresponding CT image data were as follows: PI, 1.08±0.22 cm in females and 0.85±0.27 cm in males (P>0.05); OP, 1.06±0.29 cm in females and 1.12±0.24 cm in males (P>0.05); ÐÏ´, 55.33°±4.00° in females and 55. 50°±3.43° in males (P>0.05); and Ðφ was 39.21°±2.45°in females and 35.58°±2.31°in males (P<0.05). No significant difference with respect to sex and side existed between specimens and healthy adults (P>0.05). CONCLUSIONS The measured parameter data obtained in healthy adults and cadaveric specimens provided an anatomic basis for the designation of the guide module, and thus confirmed the accuracy and safety of screw placement in fractured columns of the acetabulum.

Determination of Phenolic Compounds in Environmental Water by HPLC Combination with On-Line Solid-Phase Extraction Using Molecularly Imprinted Polymers.

A novel molecularly imprinted polymer (MIP) was synthesized using halloysite nanotubes (HNT) as matrix, ß-cyclodextrin (ß-CD) and methyl propyl acid (MAA) as functional monomers, and 2,4,6-TCP as template molecule by graft copolymerization. Infrared spectroscopy and transmission electron microscopy (TEM) were used to characterize the as-synthesized imprinted polymer. The selective recognizability of the MIP towards four phenolic analogs were determined and the recognition coefficients for 2,4,6-TCP, 2,6-DCP, 4-CP and phenol were found to be 2.17, 1.85, 2.02 and 1.36, respectively. Using as the packing material of solid-phase extraction, the imprinted polymer has been applied to on-line extraction of the four phenolic compounds in environmental water. The corresponding analytical methods to determine these four phenolic compounds have been developed. Good linear relationships were obtained over the range of 0.05-5.0 mg x L(-1). The average recoveries for spiked samples were in the range of 74.8-97.2%, and the detection limits for 2,4,6-TCP, 2,6-DCP, p-chlorophenol, phenol were 0.19, 0.20, 0.75, 0.73 mg x L(-1), respectively. The method is rapid, accurate and high selectivity. It was feasible for the determination of trace level phenolic compounds in environmental samples.

Rspo2 exacerbates rheumatoid arthritis by targeting aggressive phenotype of fibroblast-like synoviocytes and disrupting chondrocyte homeostasis via Wnt/ß-catenin pathway.

BACKGROUND: The aggressive phenotype of fibroblast-like synoviocytes (FLS) has been identified as a contributing factor to the exacerbation of rheumatoid arthritis (RA) through the promotion of synovitis and cartilage damage. Regrettably, there is currently no effective therapeutic intervention available to address this issue. Recent research has shed light on the crucial regulatory role of R-spondin-2 (Rspo2) in cellular proliferation, cartilage degradation, and tumorigenesis. However, the specific impact of Rspo2 on RA remains poorly understood. We aim to investigate the function and mechanism of Rspo2 in regulating the aggressive phenotype of FLS and maintaining chondrocyte homeostasis in the context of RA. METHODS: The expression of Rspo2 in knee joint synovium and cartilage were detected in RA mice with antigen-induced arthritis (AIA) and RA patients. Recombinant mouse Rspo2 (rmRspo2), Rspo2 neutralizing antibody (Rspo2-NAb), and recombinant mouse DKK1 (rmDKK1, a potent inhibitor of Wnt signaling pathway) were used to explore the role and mechanism of Rspo2 in the progression of RA, specifically in relation to the aggressive phenotype of FLS and chondrocyte homeostasis, both in vivo and in vitro. RESULTS: We indicated that Rspo2 expression was upregulated both in synovium and articular cartilage as RA progressed in RA mice and RA patients. Increased Rspo2 upregulated the expression of leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5), as the ligand for Rspo2, and ß-catenin in FLS and chondrocytes. Subsequent investigations revealed that intra-articular administration of rmRspo2 caused striking progressive synovitis and articular cartilage destruction to exacerbate RA progress in mice. Conversely, neutralization of Rspo2 or inhibition of the Wnt/ß-catenin pathway effectively alleviated experimental RA development. Moreover, Rspo2 facilitated FLS aggressive phenotype and disrupted chondrocyte homeostasis primarily through activating Wnt/ß-catenin pathway, which were effectively alleviated by Rspo2-NAb or rmDKK1. CONCLUSIONS: Our data confirmed a critical role of Rspo2 in enhancing the aggressive phenotype of FLS and disrupting chondrocyte homeostasis through the Wnt/ß-catenin pathway in the context of RA. Furthermore, the results indicated that intra-articular administration of Rspo2 neutralizing antibody or recombinant DKK1 might represent a promising therapeutic strategy for the treatment of RA.

A Rapid Antimicrobial Resistance Diagnostic Platform for Staphylococcus aureus Using Recombinase Polymerase Amplification.

Antimicrobial resistance (AMR) has posed a global threat to public health. The Staphylococcus aureus strains have especially developed AMR to practically all antimicrobial medications. There is an unmet need for rapid and accurate detection of the S. aureus AMR. In this study, we developed two versions of recombinase polymerase amplification (RPA), the fluorescent signal monitoring and lateral flow dipstick, for detecting the clinically relevant AMR genes retained by S. aureus isolates and simultaneously identifying such isolates at the species level. The sensitivity and specificity were validated with clinical samples. Our results showed that this RPA tool was able to detect antibiotic resistance for all the 54 collected S. aureus isolates with high sensitivity, specificity, and accuracy (all higher than 92%). Moreover, results of the RPA tool are 100% consistent with that of PCR. In sum, we successfully developed a rapid and accurate AMR diagnostic platform for S. aureus. The RPA might be used as an effective diagnostic test in clinical microbiology laboratories to improve the design and application of antibiotic therapy. IMPORTANCE Staphylococcus aureus is a species of Staphylococcus and belongs to Gram-positive. Meanwhile, S. aureus remains one of the most common nosocomial and community-acquired infections, causing blood flow, skin, soft tissue, and lower respiratory tract infections. The identification of the particular nuc gene and the other eight genes of drug-resistant S. aureus can reliably and quickly diagnose the illness, allowing doctors to prescribe treatment regimens sooner. The detection target in this work is a particular gene of S. aureus, and a POCT is built to simultaneously recognize S. aureus and analyze genes representing four common antibiotic families. We developed and assessed a rapid and on-site diagnostic platform for the specific and sensitive detection of S. aureus. This method allows the determination of S. aureus infection and 10 different AMR genes representing four different families of antibiotics within 40 min. It was easily adaptable in low-resource circumstances and professional-lacking circumstances. It should be supported in overcoming the continuous difficulty of drug-resistant S. aureus infections, which is a shortage of diagnostic tools that can swiftly detect infectious bacteria and numerous antibiotic resistance indicators.

Increased expression of osteopontin in subchondral bone promotes bone turnover and remodeling, and accelerates the progression of OA in a mouse model.

Osteopontin (OPN) has been proved to be closely related to the pathogenesis of osteoarthritis (OA), but the role of OPN in the pathogenesis of OA has not been fully clarified. Current studies on OPN in OA mostly focus on articular cartilage, synovial membrane and articular fluid, while ignoring its role in OA subchondral bone turnover and remodeling. In this study, we used a destabilization OA mouse model to investigate the role of OPN in OA subchondral bone changes. Our results indicate that increased expression of OPN accelerates the turnover and remodeling of OA subchondral bone, promotes the formation of h-type vessels in subchondral bone, and mediates articular cartilage degeneration induced by subchondral bone metabolism. In addition, our results confirmed that inhibition of PI3K/AKT signaling pathway inhibits OPN-mediated OA subchondral bone remodeling and cartilage degeneration. This study revealed the role and mechanism of OPN in OA subchondral bone, which is of great significance for exploring specific biological indicators for early diagnosis of OA and monitoring disease progression, as well as for developing drugs to regulate the metabolism and turnover of subchondral bone and alleviate the subchondral bone sclerosis of OA.

LncRNA Neat1 promotes the macrophage inflammatory response and acts as a therapeutic target in titanium particle-induced osteolysis.

Aseptic loosening (AL), secondary to particle-caused periprosthetic osteolysis, is one of the main reasons of artificial joint failure. Suppressing the macrophage inflammatory response caused by wear particles extends the life of prosthesis, and the long noncoding RNAs (lncRNAs) may play a predominant part in it. Here, titanium particles' (TiPs') stimulation increases both the cytoplasmic and nuclear levels of lncRNA Neat1 in bone marrow derived macrophages (BMDMs), which further induces the inflammatory response. Mechanically, Neat1 facilitates Bruton's tyrosine kinase (BTK) transcription by reducing the transcriptional factor KLF4, which further activates the NF-κB pathway, NLRP3 inflammation, and M1 polarization in BMDMs. Cytoplasmic Neat1 also works as an miRNA sponge in miR-188-5p-regulated BTK expression in the post-transcriptional stage. In vivo, Neat1 downregulation can reduce the TiP-induced pro-inflammatory factors and reverse the osteolysis induced by BTK overexpression. In addition, the PLGA-based microparticles loaded with si-Neat1 are developed for the treatment of the mouse calvarial osteolysis model via local injection, presenting satisfactory anti-osteolysis efficacy. These findings indicate that Neat1 is a key regulator of AL. STATEMENT OF SIGNIFICANCE: Due to released particles, aseptic loosening (AL) is the most common reason for prosthesis failure and surgical revision and represents a substantial economic burden worldwide. Herein, we reported that lncRNA Neat1 is a key regulator in regulating wear particles-induced osteolysis by activating NF-κB pathway, NLRP3 inflammation and M1 polarization via BTK, and the underlying mechanisms of Neat1-BTK interaction were further portrayed. For potential clinical application, the microparticles are developed for effective si-Neat1 delivery, leading to a dramatically enhanced effect for the treatment of osteolysis, which might be a novel strategy to extend the life of the implant.

FABP4 secreted by M1-polarized macrophages promotes synovitis and angiogenesis to exacerbate rheumatoid arthritis.

Increasing evidence shows that adipokines play a vital role in the development of rheumatoid arthritis (RA). Fatty acid-binding protein 4 (FABP4), a novel adipokine that regulates inflammation and angiogenesis, has been extensively studied in a variety of organs and diseases. However, the effect of FABP4 on RA remains unclear. Here, we found that FABP4 expression was upregulated in synovial M1-polarized macrophages in RA. The increase in FABP4 promoted synovitis, angiogenesis, and cartilage degradation to exacerbate RA progression in vivo and in vitro, whereas BMS309403 (a FABP4 inhibitor) and anagliptin (dipeptidyl peptidase 4 inhibitor) inhibited FABP4 expression in serum and synovial M1-polarized macrophages in mice to alleviate RA progression. Further studies showed that constitutive activation of mammalian target of rapamycin complex 1 (mTORC1) by TSC1 deletion specifically in the myeloid lineage regulated FABP4 expression in macrophages to exacerbate RA progression in mice. In contrast, inhibition of mTORC1 by ras homolog enriched in brain (Rheb1) disruption specifically in the myeloid lineage reduced FABP4 expression in macrophages to attenuate RA development in mice. Our findings established an essential role of FABP4 that is secreted by M1-polarized macrophages in synovitis, angiogenesis, and cartilage degradation in RA. BMS309403 and anagliptin inhibited FABP4 expression in synovial M1-polarized macrophages to alleviate RA development. Hence, FABP4 may represent a potential target for RA therapy.

Spermidine activates RIP1 deubiquitination to inhibit TNF-α-induced NF-κB/p65 signaling pathway in osteoarthritis.

Spermidine has been known to inhibit the production of pro-inflammatory cytokines. However, there are no reports about anti-inflammatory effects of spermidine on osteoarthritis (OA). Herein, we examined whether OA progression could be delayed by intraperitoneal injection (i.p.) of spermidine in the anterior cruciate ligament transection (ACLT) and TNF-α induced arthritis (TIA) mouse models. During the process, human FLS cells (H-FLS) were used to investigate the potential ubiquitination mechanism of spermidine-mediated RIP1 in TNF-α-induced NF-κB/p65 signaling. We found that spermidine attenuated synovitis, cartilage degeneration and osteophyte formation, resulting in substantially lower OARSI scores and TNF-α scores in spermidine-treated ACLT and TIA mice. In terms of the mechanism, 9 µM spermidine did not affect the viability, proliferation, cell cycle and apoptosis of H-FLS, and exerted inhibitory effects by activating CYLD-mediated RIP1 deubiquitination on TNF-α-induced NF-κB/p65 signaling in H-FLS. From these data, we can conclude that spermidine attenuates OA progression by the inhibition of TNF-α-induced NF-κB pathway via the deubiquitination of RIP1 in FLS. Therefore, intake of spermidine could be a potential therapy for preventing OA.

Activation of mTORC1 in subchondral bone preosteoblasts promotes osteoarthritis by stimulating bone sclerosis and secretion of CXCL12.

Increasing evidences show that aberrant subchondral bone remodeling plays an important role in the development of osteoarthritis (OA). However, how subchondral bone formation is activated and the mechanism by which increased subchondral bone turnover promotes cartilage degeneration during OA remains unclear. Here, we show that the mechanistic target of rapamycin complex 1 (mTORC1) pathway is activated in subchondral bone preosteoblasts (Osterix+) from OA patients and mice. Constitutive activation of mTORC1 in preosteoblasts by deletion of the mTORC1 upstream inhibitor, tuberous sclerosis 1, induced aberrant subchondral bone formation, and sclerosis with little-to-no effects on articular cartilage integrity, but accelerated post-traumatic OA development in mice. In contrast, inhibition of mTORC1 in preosteoblasts by disruption of Raptor (mTORC1-specific component) reduced subchondral bone formation and cartilage degeneration, and attenuated post-traumatic OA in mice. Mechanistically, mTORC1 activation promoted preosteoblast expansion and Cxcl12 secretion, which induced subchondral bone remodeling and cartilage degeneration during OA. A Cxcl12-neutralizing antibody reduced cartilage degeneration and alleviated OA in mice. Altogether, these findings demonstrate that mTORC1 activation in subchondral preosteoblasts is not sufficient to induce OA, but can induce aberrant subchondral bone formation and secrete of Cxcl12 to accelerate disease progression following surgical destabilization of the joint. Pharmaceutical inhibition of the pathway presents a promising therapeutic approach for OA treatment.

Correction to: Activation of mTORC1 in subchondral bone preosteoblasts promotes osteoarthritis by stimulating bone sclerosis and secretion of CXCL12.

[This corrects the article DOI: 10.1038/s41413-018-0041-8.].

Hesperidin inhibits synovial cell inflammation and macrophage polarization through suppression of the PI3K/AKT pathway in complete Freund's adjuvant-induced arthritis in mice.

Rheumatoid arthritis (RA) is an autoimmune disease characterized by synovitis. Synovitis can cause joint injury by releasing inflammatory factors and metalloproteinases (MMPs). Therefore, it is necessary to find drugs that can control synovitis in the process of RA. Herein, we investigate the anti-inflammatory effect of Hesperidin (HSN) on fibroblast-like synovial (FLS) cells induced by lipopolysaccharide (LPS) and the protective action of M1 polarization level of synovial macrophages on antigen-induced arthritis (AIA) in order to elucidate the reduction of inflammatory cytokines and MMPs and the inhibition of macrophage activation. The functional effect of HSN on LPS-induced mRNA and protein expressions of inflammatory cytokines and MMPs in FLS cells as well as on LPS-induced macrophage M1 and M2 polarization markers was determined by quantitative real-time PCR (qPCR) or Western blot analyses, respectively. AIA in 2-month-old mice was generated using intraperitoneal injection with HSN (20 mg/kg/day) or LY294002 (20 mg/kg/day). The results show HSN significantly inhibited the LPS-induced gene expression of the inflammatory mediators. Furthermore, treatment with HSN relieved the antigen-induced arthritis and reduced the protein levels of MMP3, MMP9, and MMP13 in FLS and inhibited the polarization of macrophages to M1. Based on the results of our analyses, we concluded that HSN has significant anti-inflammatory activities and reduces the potential of MMPs in rheumatoid arthritis and the degree of polarization of macrophages to M1. Through the study of signaling pathways, we established that the inhibition of the PI3K/AKT signaling pathway by HSN may show therapeutic effects in the progression of rheumatoid arthritis.

Masquelet technique versus Ilizarov bone transport for reconstruction of lower extremity bone defects following posttraumatic osteomyelitis.

OBJECTIVE: This study was to compare the effectiveness of Masquelet technique versus Ilizarov bone transport in the treatment of lower extremity bone defects following posttraumatic osteomyelitis. PATIENTS AND METHODS: We retrospectively reviewed 39 patients who had been treated at our department for lower extremity bone defects following posttraumatic osteomyelitis. They were 30 males and 9 females with a mean age of 39.18 (range, 12-63 years). The infected bone defects involved 26 tibias and 13 femurs. The mean length of the bone defects after radical debridement was 6.76cm (range, 2.7-15.7cm). Masquelet technique (MT, group A) was used in 20 patients and Ilizarov bone transport (IBT, group B) in 19 ones. The measurements were bone outcomes (union, deformity, infection and leg-length discrepancy) and functional outcomes (significant limping, joint contracture, soft tissue dystrophy, pain and inactivity). RESULTS: The mean follow-up after removal of the apparatus was 25.26 months (range, 14-51 months). The mean finite fixator time was 10.15 months (range, 8-14 months) in group A versus 17.21 months (range, 11-24 months) in group B. The bone outcomes were similar between groups A and B [excellent (5 vs. 7), good (10 vs.9), fair (4 vs. 2) and poor (1 vs. 1)]; group A showed better functional outcomes than group B [excellent (8 vs. 3), good (9 vs. 6), fair (3 vs. 8) and poor (0 vs. 2)]. CONCLUSIONS: In the treatment of segmental lower extremity bone defects following posttraumatic osteomyelitis, both IBT and MT can lead to satisfactory bone results while MT had better functional results, especially in femoral cases. IBT should be preferred in cases of limb deformity and MT may be a better choice in cases of periarticular bone defects.