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Construction and Evaluation of a Murine Calvarial Osteolysis Model by Exposure to CoCrMo Particles in Aseptic Loosening

Wear particle-induced osteolysis is a major cause of aseptic loosening in arthroplasty failure, but the underlying mechanism remains unclear. Due to long ...

Nanjing University Medical School

                    
The purpose of this study was to investigate the profile of histone deacetylase (HDAC) activity and expression in osteosarcoma cells and tissues from osteosarcoma patients and to examine the mechanism by which a histone deacetylase (HDAC) inhibitor, Trichostatin A (TSA), promotes the apoptosis of osteosarcoma cells.HDAC activity and histone acetyltransferase (HAT) activity were determined in nuclear extracts of MG63 cells, hFOB 1.19 cells and tissues from 6 patients with primary osteosarcoma. The protein expression of Class I HDACs (1, 2, 3 and 8) and the activation of the p53 signaling pathway were examined by Western blot. Cell growth and apoptosis were determined by 3-(4, 5-dimethyl-2-thiazolyl)-2H-tetrazolium bromide (MTT) assay and flow cytometry, respectively.Nuclear HDAC activity and class I HDAC expression were significantly higher in MG63 cells than in hFOB 1.19 cells, and a similar trend was observed in the human osteosarcoma tissues compared with the paired adjacent non-cancerous tissues. TSA significantly inhibited the growth of MG63 cells and promoted apoptosis in a dose-dependent manner through p53 signaling pathway activation.Class I HDACs play a central role in the pathogenesis of osteosarcoma, and HDAC inhibitors may thus have promise as new therapeutic agents against osteosarcoma.

Histone Deacetylase Inhibitor Trichostatin a Promotes the Apoptosis of Osteosarcoma Cells through p53 Signaling Pathway Activation.

We hypothesized that SIRT1 downregulation in osteoblasts induced by wear particles was one of the reasons for particle-induced osteolysis (PIO) in total joint arthroplasty failure. In the present study, the expression of SIRT1 was examined in osteoblasts treated with TiAl6V4 particles (TiPs) and CoCrMo particles (CoPs) from materials used in prosthetics and specimens from PIO animal models. To address whether SIRT1 downregulation triggers inflammatory responses and apoptosis in osteoblasts, the effect of a SIRT1 activator, resveratrol on the expression of inflammatory cytokines and apoptosis in particle-treated osteoblasts was tested. The results demonstrated that SIRT1 expression was significantly downregulated in particle-treated osteoblasts and PIO animal models. Both pharmacological activation and overexpression of SIRT1 dramatically reduced the particle-induced expression of inflammatory cytokines and osteoblast apoptosis through NF-κB and p53 signaling, respectively. Furthermore, in PIO animal models, resveratrol significantly reduced the severity of osteolysis. Collectively, the results of the present study indicated that SIRT1 plays a vital role in the pathogenesis of aseptic loosening, and further treatment targeted at SIRT1 possibly lead to novel approaches for prevention of aseptic prosthesis loosening.

SIRT1 protects osteoblasts against particle-induced inflammatory responses and apoptosis in aseptic prosthesis loosening.

Aseptic loosening is the most common cause of total hip arthroplasty (THA) failure, and osteolysis induced by wear particles plays a major role in aseptic loosening. Various pathways in multiple cell types contribute to the pathogenesis of osteolysis, but the role of Sirtuin 1 (SIRT1), which can regulate inflammatory responses through its deacetylation, has never been investigated. We hypothesized that the downregulation of SIRT1 in macrophages induced by metal nanoparticles was one of the reasons for osteolysis in THA failure. In this study, the expression of SIRT1 was examined in macrophages stimulated with metal nanoparticles from materials used in prosthetics and in specimens from patients suffering from aseptic loosening. To address whether SIRT1 downregulation triggers these inflammatory responses, the effects of the SIRT1 activator resveratrol on the expression of inflammatory cytokines in metal nanoparticle-stimulated macrophages were tested. The results demonstrated that SIRT1 expression was significantly downregulated in metal nanoparticle-stimulated macrophages and clinical specimens of prosthesis loosening. Pharmacological activation of SIRT1 dramatically reduced the particle-induced expression of inflammatory cytokines in vitro and osteolysis in vivo. Furthermore, SIRT1 regulated particle-induced inflammatory responses through nuclear factor kappa B (NF-κB) acetylation. Thus, the results of this study suggest that SIRT1 plays a key role in metal nanoparticle-induced inflammatory responses and that targeting the SIRT1 pathway may lead to novel therapeutic approaches for the treatment of aseptic prosthesis loosening.

The metal nanoparticle-induced inflammatory response is regulated by SIRT1 through NF-κB deacetylation in aseptic loosening.

This study aimed to evaluate the association between cardiovascular autonomic neuropathy (CAN) and left ventricular diastolic dysfunction (LVDD) in type 2 diabetes patients.

Cardiovascular Autonomic Neuropathy Is an Independent Risk Factor for Left Ventricular Diastolic Dysfunction in Patients with Type 2 Diabetes.

                    
Diabetic peripheral neuropathies are the common chronic complications of diabetes, but the diagnosis is insensitive by physical examination in busy outpatients. Here we evaluated the performance of SUDOSCAN in screening diabetic peripheral neuropathies in Chinese type 2 diabetic patients.The study enrolled 180 patients for annually screening. All patients underwent neurological symptoms assessment, clinical examination, nerve conduction studies and cardiovascular autonomic reflex tests. SUDOSCAN was tested and evaluated with electrochemical skin conductance in hands and feet, asymmetry ratio in hands and feet and predicted cardiac neuropathy.Patients enrolled had an average age of 56.1 years, 9.8 years of diabetic duration. Patients with diabetic sensorimotor polyneuropathy showed significantly lower electrochemical skin conductance in feet and higher asymmetry ratio in feet compared with those without. Sensitivity and specificity of asymmetry ratio in feet for diagnosing diabetic sensorimotor polyneuropathy were 88.2% and 46.9% and area under ROC curve was 0.713. Patients with cardiovascular autonomic neuropathy showed significantly lower electrochemical skin conductance in hands and feet, and higher asymmetry ratio in feet and predicted cardiac neuropathy compared with those without. Sensitivity and specificity of electrochemical skin conductance in feet in diagnosing cardiovascular autonomic neuropathy were 85.6% and 76.1% with an area under ROC curve of 0.859.SUDOSCAN is a sensitive test to detect diabetic peripheral neuropathy in China and could be an effective screening tool in in busy outpatients and primary health care.

The Application of SUDOSCAN for Screening Diabetic Peripheral Neuropathy in Chinese Population Screening DPN by SUDOSCAN.

Background: To compare the risk of type 2 diabetes (T2DM) between patients with and without chronic osteomyelitis (COM), both in humans and in mice, and to explore risk factors in COM patients who developed T2DM. Methods: One hundred seven patients with COM and 114 patients without COM were consecutively enrolled and retrospectively analysed. Clinical data concerning the time to develop diabetes, glucose metabolism, lipid metabolism, inflammatory factors, mental health and frequency of specialist visits were collected. A mouse model of osteomyelitis was used to verify the presence of impaired glucose metabolism and depression. All data were processed by SPSS. Results: The incidence of T2DM was 2.37-fold higher in patients with COM than in those without. In COM patients, subjects with T2DM (DDM) had higher BMI, less exercise and more frequent visits to specialists than those without (Con). Glucose and lipid metabolism were worse in patients with DDM. Patients with DDM had higher levels of white blood cells (12.9±2.1×109/L vs. 11.7±2.2×109/L, p=0.027), CRP (28.4±4.5 mg/L vs. 22.0±4.8 mg/L, p<0.001), TNF-α (13.5±5.0 pg/mL vs. 9.4±2.6 pg/mL, p= 0.003) and IL-6 (12.9±3.2 pg/mL vs. 9.2±2.7 pg/mL, p<0.001). Significantly increased fasting blood glucose concentrations and impairment of oral glucose tolerance tests were also observed in mice modelling osteomyelitis, which were accompanied by elevated TNF-α and IL-6 levels. Furthermore, the proportion of depression (63.2% vs. 35.2%, p=0.003) and severe anxiety (31.6% vs. 9.1%, p=0.002) were significantly higher in the DDM group. Osteomyelitis mice showed obvious depressive-like behaviours. The levels of TNF-α, IL-6, CRP, BMI, and LDL; lack of exercise; SAS; HAQ; and SF36 assessment were risk factors for the development of T2DM in COM patients. Conclusions: Chronic osteomyelitis increased the incidence of T2DM in both humans and mice. Inflammation, mental illness and lack of exercise were risk factors for the occurrence of T2DM in osteomyelitis. Comprehensive consideration of patient history, including metabolism and mental health, is needed in planning future treatment.

Jiewen Jin

Center for Translational Medicine,
Jiangsu Key Laboratory for Molecular Medicine

Nanjing University Medical School

Construction and Evaluation of a Murine Calvarial Osteolysis Model by Exposure to CoCrMo Particles in Aseptic Loosening

Jiewen Jin

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Center for Translational Medicine,Jiangsu Key Laboratory for Molecular Medicine

Nanjing University Medical School

Construction and Evaluation of a Murine Calvarial Osteolysis Model by Exposure to CoCrMo Particles in Aseptic Loosening

Center for Translational Medicine,
Jiangsu Key Laboratory for Molecular Medicine