TNF-α regulates the early development of avascular necrosis of the femoral head by mediating osteoblast autophagy and apoptosis via the p38 MAPK/NF-κB signaling pathway.

Previous studies have shown that the tumor necrosis factor-α (TNF-α) levels in serum and bone tissues formed in avascular necrosis of femoral head (ANFH) patients were higher than those of normal individuals, indicating TNF-α might play a role in the pathogenesis of ANFH. However, the underlying mechanisms remain unclear. Hematoxylin and eosin staining was performed to show the pathological changes of ANFH bone tissues. TNF-α expression in normal and ANFH tissues was examined by quantitative real-time polymerase chain reaction and western blot analyses. Osteoblast autophagy and apoptosis, as well as signaling pathways activation, were measured by their corresponding marker proteins. Osteoblast proliferation, autophagy, and apoptosis were evaluated using cell counting kit-8, transmission electron microscopy, and flow cytometry. The structures of bone tissues of ANFH were obviously damaged. TNF-α expression was significantly upregulated in ANFH bone tissues compared to normal tissues. Autophagy and apoptosis were remarkably promoted, and p38 mitogen-activated protein kinase (MAPK)/nuclear factor-κB (NF-κB) signaling pathways were markedly activated in ANFH. Suppression of the p38 MAPK/NF-κB pathway significantly attenuated the TNF-α-induced autophagy, however, enhanced the TNF-α-induced apoptosis in osteoblasts. Increased TNF-α in ANFH regulated osteoblast autophagy and apoptosis by p38 MAPK/NF-κB signaling pathways, blocking the pathway by inhibitors exacerbated TNF-α-induced apoptosis through impairing autophagy flux.

Association of global DNA hypomethylation with post-operative cognitive dysfunction in elderly patients undergoing hip surgery.

BACKGROUND: Post-operative cognitive dysfunction (POCD) is a decline of cognitive status that commonly occurs after surgery in elderly patients. Whether DNA methylation is associated with the development of POCD remains unclear. METHODS: Subjects (N = 124) older than 65 years-of-age undergoing hip replacement surgery were enrolled. A battery of neuropsychiatric tests was used to examine the perioperative cognitive function of the patients. Early POCD was analyzed using the reliable change index (RCI), and subjects were diagnosed with POCD if RCI < -1.96. Peripheral leukocyte DNA was isolated, and DNA methylation was measured via 5-methylcytosine (mC) using Elisa. RESULTS: Twenty-four patients (19.4%) developed early POCD. There was no difference in baseline 5-mC levels by POCD status. The 5-mC levels significantly decreased on day 7 after surgery in patients who developed early POCD (P = .004), but did not change in non-POCD patients. Moreover, post-operative 5-mC levels were significantly lower in POCD patients than those in non-POCD patients (P = .003). Bivariate logistic models adjusted for age, gender, BMI, duration of anesthesia, and education level clearly demonstrated an independent association between post-operative 5-mC level and early POCD. CONCLUSIONS: Post-operative global hypomethylation of leukocyte DNA was associated with the development of early POCD. TRIAL REGISTRATION: ClinicalTrial, NCT02965235. Registered 16 November 2016, https://www.clinicaltrials.gov/ct2/results?term=NCT02965235&rank=1#rowId0.

MicroRNA-29a suppresses the invasion and migration of osteosarcoma cells by regulating the SOCS1/NF-κB signalling pathway through negatively targeting DNMT3B.

The present study aimed to investigate the roles of the microRNA­29a/DNA methyltransferase 3B/suppressor of cytokine signalling 1 (miR­29a/DNMT3B/SOCS1) axis in the invasion and the migration of osteosarcoma (OS). The expression levels of miR­29a, DNMT3B and SOCS1 were determined in tissue samples and OS cell lines by reverse transcription­quantitative polymerase chain reaction (PCR). Apoptosis was measured using flow cytometry analysis. Transwell and wound healing assays were conducted to measure the invasion and migration abilities of OS cells, respectively. A dual­luciferase reporter assay was also conducted to determine the interaction between DNMT3B and miR­29a, while methylation­specific PCR was used to detect the methylation of SOCS1. Western blotting was performed to determine the protein levels of DNMT3B and SOCS1, as well as the levels of proteins associated with epithelial­mesenchymal transition (EMT), apoptosis and the nuclear factor (NF)­κB signalling pathway. The results demonstrated that miR­29a and SOCS1 were downregulated, and DNMT3B was upregulated in both OS tissues and cell lines. The expression of miR­29a and SOCS1 was found to be associated with advanced clinical stage and distant metastasis. In addition, the dual­luciferase reporter assay revealed that DNMT3B was a direct target of miR­29a. Overexpression using miR­29a mimics decreased DNMT3B expression and the methylation level of SOCS1, which resulted in the upregulation of SOCS1 in U2OS and MG­63 cells, while miR­29a inhibition led to the opposite results. Transfection with miR­29a mimics also promoted the apoptosis, and inhibited the invasion, migration and EMT process of OS cells, while it markedly reduced the nuclear translocation of p65 and IκB­α degradation. Treatment with 5­aza­2'­deoxycytidine worked together with miR­29a mimics to synergistically enhance the aforementioned effects. By contrast, the effects induced by miR­29a were partly reversed upon co­transfection with SOCS1 siRNA. In conclusion, miR­29a promoted the apoptosis, and inhibited the invasion, migration and EMT process of OS cells via inhibition of the SOCS1/NF­κB signalling pathway by directly targeting DNMT3B.

[Evaluation and treatment of hemorrhage after hip and knee arthroplasty in the aged].

OBJECTIVE: To analyze the evaluation and treatment of blood loss during total hip arthroplasty (THA) and total knee arthroplasty (TKA) in the aged . METHODS: We retrospectively surveyed the blood loss and the rehabilitation of 46 cases of TKA and 146 cases of THA older than 60. RESULTS: In the group younger than 70, the mean total blood loss of THA was 1425 mL and the hidden hemorrhage 729 mL (51%); following the TKA, the mean total loss was 1386 mL and the hidden hemorrhage was 890 mL (64%). In the group 70 and older, the mean total blood loss of THA was 1435 mL and the hidden hemorrhage was 769 mL (53%)û following the TKA, the mean total loss was 1380 mL and the hidden hemorrhage was 910 mL (65%). The difference of hidden hemorrhage between the THA and the TKA was both significant by different (p< 0.05). Age played an important part in the THA group (p< 0.05), but not in the TKA group (> 0.05). CONCLUSION: The aged have poor resistance to blood loss. Hidden hemorrhage in the TKA or THA perhaps is the primary part of the blood loss. Prompt treatment is helpful for the rehabilitation.

Effects of Alendronate Sodium Content on the Interface Strengths of Composite Acrylic Bone Cement.

Objective. Aim to study how the content of alendronate affected shear strengths at bone-bone cement-metal interfaces. Methods. All samples were divided into 6 groups, G0-G5. On the 1st and 60th day after surgery, bone-bone cement interface shear strengths and bone densities were examined. Interface strengths of metal-bone cement specimens were studied before immersion and 4 weeks after immersion. Results. On the 60th day, bone-bone cement interface shear strengths and bone densities showed significant differences (P < 0.05), and compared with G0, G2-G5 values increased significantly (P < 0.05), and the peak value was met in G3. Compared with the 1st day, on the 60th postoperative day both factors decreased significantly in G0 and G1 (P < 0.05). Four weeks after immersion, with the increasing dose of alendronate, the shear strengths decreased gradually and in G5 decreased significantly (P < 0.05). Compared with before immersion, the metal-bone cement interface strengths decreased significantly 4 weeks after immersion (P < 0.05). Conclusions. 50-500 mg alendronate in 50 g cement powders could prevent the decrease of shear strengths at bone-bone cement interfaces and had no effect on metal-bone cement interface strengths. While the addition dose was 100 mg, bone cement showed the best strengths.

Hydroxyapatite/tricalcium phosphate matrix scaffold as cell carriers in vitro.

OBJECTIVE: To explore the possibility of hydroxyapatite/tricalcium phosphate (HA/TCP) matrix scaffold as cell carriers in tissue engineering, and to provide a direct evidence for the resurfacing of matrix scaffold. METHODS: Human bone marrow stromal cells (hBMSCs) and umbilical vein endothelial cells (UVECs) were co-cultured on the surface of matrix scaffold. The morphologic characters during culture on HA/TCP matrix scaffold's surfaces were checked by light microscope, fluorescence microscope, and scanning electronic microscope. RESULTS: Both human bone marrow stromal cells and human umbilical vein endothelial cells showed good biocompatibility with HA/TCP matrix scaffold. The cell growth into the micropore of HA/TCP matrix scaffold could be seen under both fluorescence microscopy and scaning electron microscopy. CONCLUSION: HA/TCP matrix scaffold can be used as a vehicle for the cell transplantation.

Expression of NF-κB and osteopontin of synovial fluid of patients with knee osteoarthritis.

OBJECTIVE: To explore the significance of osteopontin and nuclear factor κB (NF-κB) expression in patients with knee osteoarthritis. METHODS: RT-PCR and enzyme-linked immunosorbent assay were used to measure the Osteopontin (OPN) and NF-κB concentration of knee joint synovial fluid of patients with knee osteoarthritis and trauma fractures, and analyze the relationship between the expressiones of them. RESULTS: OPN and NF-κB expression at the mRNA and protein levels of patients with knee osteoarthritis were significantly higher than the control group. the result showed statistical significance (P<0.05). There was a positive correlation between the OPN levels in synovial fluid of patients with knee osteoarthritis and NF-κB expression levels (P<0.05). CONCLUSIONS: The high expression of OPN and NF-κB are closely related to occurrence and development of knee osteoarthritis.

Advances in bone repair with nanobiomaterials: mini-review.

Nanotechnology has emerged to be one of the most powerful engineering approaches in the past half a century. Nanotechnology brought nanomaterials for biomedical use with diverse applications. In the present manuscript we summarize the recent progress in adopting nanobiomaterials for bone healing and repair approaches. We first discuss the use of nanophase surface modification in manipulating metals and ceramics for bone implantation, and then the use of polymers as nanofiber scaffolds in bone repair. Finally we briefly present the potential use of the nanoparticle delivery system as adjunct system in promoting bone regeneration following fracture.

Could insertion of the particles that induce osteolysis be a new treatment option in heterotopic ossification?

Heterotopic ossification (HO) is the formation of the bone outside the skeletal system, it is a common complication of surgery or trauma. The abnormal deposition or precipitation of calcium phosphate in tissues may be massive and clinically significant sometimes. Severe ossification often reduce joint function and induce pain. Unfortunately, to date, there is no satisfactory treatment available yet. Nowadays, periprosthetic osteolysis induced by wear debris is the most widely accepted cause of aseptic loosening after total joint replacement. A large number of researches have identified metal particles can stimulate bone resorption by targeting osteoclasts. So it is hypothesized that the insertion of metal particles in the region surrounding heterotopic bone could be a new treatment option in HO.