Exosomes Secreted from Hypoxia-Preconditioned Mesenchymal Stem Cells Prevent Steroid-Induced Osteonecrosis of the Femoral Head by Promoting Angiogenesis in Rats.

Recent studies have suggested that exosomes exert similar therapeutic effects to those of mesenchymal stem cells (MSCs) in regenerative medicine and MSCs-derived exosomes exhibit therapeutic effects on steroid-induced osteonecrosis of the femoral head (ONFH). Furthermore, reparative functions of exosomes from MSCs are enhanced by hypoxia treatment of the cells. However, there are no related reports about whether exosomes derived from hypoxia-preconditioned MSCs could show better therapeutic effects on steroid-induced ONFH. In vitro, we investigated the effects of hypoxia precondition on exosomes derived from bone marrow mesenchymal stem cells (BMMSCs) from rats and the proangiogenic ability of exosomes derived from hypoxia-preconditioned BMMSCs. In vivo, we investigated the role of exosomes from hypoxia-preconditioned BMMSCs on angiogenesis and protecting osteonecrosis in a rat ONFH model. We found that the potential of the proangiogenic ability of exosomes derived from hypoxia-preconditioned BMMSCs was higher than exosomes derived from BMMSCs cultured under normoxia. Exosomes derived from hypoxia-preconditioned BMMSCs significantly promoted proliferation, migration, vascular endothelial growth factor (VEGF) expression, and tube formation of human umbilical vein endothelial cells (HUVECs) compared with exosomes derived from BMMSCs cultured under normoxia. Administration of exosomes derived from hypoxia-preconditioned BMMSCs significantly prevented bone loss and increased vessel volume in the femoral head compared with exosomes derived from BMMSCs cultured under normoxia. Taken together, our data suggest that exosomes derived from hypoxia-preconditioned BMMSCs exert better therapeutic effects on steroid-induced ONFH by promoting angiogenesis and preventing bone loss.

The Proosteogenic and Proangiogenic Effects of Small Extracellular Vesicles Derived from Bone Marrow Mesenchymal Stem Cells Are Attenuated in Steroid-Induced Osteonecrosis of the Femoral Head.

Small extracellular vesicles (sEVs) derived from bone marrow mesenchymal stem cells (BMMSCs) from individuals with steroid-induced osteonecrosis of the femoral head (ONFH) have not been studied. The objective of the present study was to compare the proosteogenic and proangiogenic effects of sEVs derived from BMMSCs from rats with steroid-induced ONFH (oBMMSCs-sEVs) and sEVs derived from BMMSCs from normal rats (nBMMSCs-sEVs). BMMSCs were isolated from steroid-induced ONFH rats and healthy rats. sEVs were isolated and characterized by Western blotting analysis of exosomal surface biomarkers and by transmission electron microscopy. The impacts of nBMMSCs-sEVs and oBMMSCs-sEVs on the proliferation and osteogenic differentiation of BMMSCs were determined via cell proliferation assay, alizarin red staining, and alkaline phosphatase activity assay. Enzyme-linked immunosorbent assay and tube formation assay were conducted to investigate the effect of nBMMSCs-sEVs and oBMMSCs-sEVs on the angiogenic potential of human umbilical vein endothelial cells (HUVECs). The expression of relevant genes was detected by quantitative real-time polymerase chain reaction analysis, and the expression of ß-catenin was detected by immunofluorescence. Both nBMMSCs-sEVs and oBMMSCs-sEVs promoted proliferation, osteogenic differentiation, and ß-catenin expression of BMMSCs and enhanced angiogenesis of HUVECs. However, compared with nBMMSCs-sEVs, oBMMSCs-sEVs exhibited attenuated effects. Our findings indicated that the proosteogenic and proangiogenic effects of sEVs were partially attenuated in steroid-induced ONFH. Therefore, this study might offer guidance for the selection of source cells for sEV therapy in the future.

Relationship of common variants in MPP7, TIMP2 and CASP8 genes with the risk of chronic achilles tendinopathy.

Previous etiologic studies have indicated that both environmental and genetic factors play important roles in the occurrence and development of chronic Achilles tendinopathy (AT). A recent study documented the results of the largest genome-wide association study for chronic AT to date, indicating that MPP7, TIMP2 and CASP8 may be involved in the occurrence and development of chronic AT. In this study, we aimed to investigate whether MPP7, TIMP2 and CASP8 were associated with susceptibility to chronic AP in a Han Chinese population. A total of 3,680 study subjects comprised 1,288 chronic AT cases, and 2,392 healthy controls were recruited. Forty-four tag SNPs (7 from CASP8, 20 from MPP7, and 17 from TIMP2) were genotyped in the study. Genetic association analyses were performed at both single marker and haplotype levels. Functional consequences of significant SNPs were examined in the RegulomeDB and GTEx databases. Two SNPs, SNP rs1937810 (OR [95%CI] = 1.20 [1.09-1.32], χ2 = 13.50, P = 0.0002) in MPP7 and rs4789932 (OR [95%CI] = 1.24 [1.12-1.37], χ2 = 17.98, P = 2.23 × 10-5) in TIMP2, were significantly associated with chronic AT. Significant eQTL signals for SNP rs4789932 on TIMP2 were identified in human heart and artery tissues. Our results provide further supportive evidence for the association of the TIMP2 and MPP7 genes with chronic AT, which supports important roles for TIMP2 and MPP7 in the etiology of chronic AT, adding to the current understanding of the susceptibility of chronic AT.

BADGE, a synthetic antagonist for PPARγ, prevents steroid-related osteonecrosis in a rabbit model.

BACKGROUND: It was indicated that inhibition of PPARγ probably represents a novel therapy for steroid-related osteonecrosis. In this study, we investigated the preventive effects of PPARγ inhibition on steroid-related osteonecrosis in a rabbit model. METHODS: Rabbits were randomly divided into three groups (normal group, model group and BADGE group). Osteonecrosis was induced in rabbits in the model group and the BADGE group. The BADGE group also received bisphenol a diglycidyl ether(BADGE), a PPARγ antagonist, for 6 weeks. RESULTS: Histopathological results indicated that rabbits treated with BADGE exhibited significantly reduced osteonecrotic changes, incidence of osteonecrosis and bone marrow adiposity. Furthermore, BADGE-treated rabbits exhibited reduced intraosseous pressure and increased femoral blood perfusion. Micro-computed tomography and bone histomorphometry indicated that the BADGE group exhibited significantly improved bone quality and mineral appositional rate compared with the model group. Furthermore, the BADGE group showed a significant increase in circulating levels of the bone formation marker osteocalcin and reduced levels of the bone resorption marker TRACP. Overall, BADGE-treated rabbits exhibited reduced marrow adiposity concomitant with improved bone formation. CONCLUSIONS: In conclusion, these observations demonstrated that pharmacological inhibition of PPARγ might represent an effective therapy for steroid-related osteonecrosis in the near future.

Protective effects of molecular hydrogen on steroid-induced osteonecrosis in rabbits via reducing oxidative stress and apoptosis.

BACKGROUND: The objective of this study was to investigate the protective effects of molecular hydrogen, a novel and selective antioxidant, on steroid-induced osteonecrosis (ON) in a rabbit model. METHODS: Sixty rabbits were randomly divided into two groups (model group and hydrogen group). Osteonecrosis was induced according to an established protocol of steroid-induced ON. Rabbits in the hydrogen group were treated with intraperitoneal injections of molecular hydrogen at 10 ml/kg body weight for seven consecutive days. Plasma levels of total cholesterol, triglycerides, soluble thrombomodulin(sTM), glutathione(GSH) and malondialdehyde(MDA) were measured before and after steroid administration. The presence or absence of ON was examined histopathologically. Oxidative injury and vascular injury were assessed in vivo by immunohistochemical staining of 8-hydoxy-2-deoxyguanosine(8-OHdG) and MDA, and ink artery infusion angiography. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assays were performed to measure apoptosis. RESULTS: The incidence of steroid-induced ON was significantly lower in hydrogen group (28.6%) than that in model group (68.0%). No statistically differences were observed on the levels of total cholesterol and triglycerides. Oxidative injury, vascular injury and apoptosis were attenuated in the hydrogen group compared with those in the model group in vivo. CONCLUSIONS: These results suggested that molecular hydrogen prevents steroid-induced osteonecrosis in rabbits by suppressing oxidative injury, vascular injury and apoptosis.

Lithium prevents rat steroid-related osteonecrosis of the femoral head by ß-catenin activation.

This study explored the use of lithium to prevent rat steroid-related osteonecrosis of the femoral head (ONFH) through the modulation of the ß-catenin pathway. ONFH was induced by methylprednisolone combined with lipopolysaccharide, and serum lipids were analyzed. ONFH was detected by hematoxylin-eosin staining. Micro-CT-based angiography and bone scanning were performed to analyze vessels and bone structure, respectively. Immunohistochemical staining for peroxisome proliferator-activated receptor gamma (PPARγ), bone morphogenetic protein-2 (BMP-2), and vascular endothelial growth factor (VEGF) was analyzed. Protein levels of phospho-glycogen synthase kinase-3ß at Tyr-216 (p-Tyr(216) GSK-3ß), total glycogen synthase kinase-3ß (GSK-3ß) and ß-catenin, as well as mRNA levels of GSK-3ß and ß-catenin in femoral heads, were assessed. The rate of empty bone lacunae in the femoral heads was lower in the lithium and control groups than in the model group. The lithium group showed preventive effects against steroid-related vessel loss by micro-CT-based angiography and VEGF staining. Lithium treatment improved hyperlipidemia and reduced PPARγ expression. Moreover, lithium improved steroid-related bone loss in micro-CT bone scans and BMP-2 staining analyses. Furthermore, local ß-catenin was reduced in steroid-related ONFH, and lithium treatment increased ß-catenin expression while reducing p-Tyr(216) GSK-3ß levels. The local ß-catenin pathway was inhibited during steroid-related ONFH. Lithium may enhance angiogenesis and stabilize osteogenic/adipogenic homeostasis during steroid-related ONFH in rats by activating the ß-catenin pathway.

Lithium chloride attenuates the abnormal osteogenic/adipogenic differentiation of bone marrow-derived mesenchymal stem cells obtained from rats with steroid-related osteonecrosis by activating the ß-catenin pathway.

Steroid-related osteonecrosis of the femoral head (ONFH) may be a disease that results from the abnormal osteogenic/adipogenic differentiation of bone marrow-derived mesenchymal stem cells (BMMSCs). In the present study, we examined the possible use of lithium in an aim to reverse the abnormal osteogenic/adipogenic differentiation of BMMSCs isolated from rats with steroid-related ONFH (termed ONFH-BMMSCs). BMMSCs obtained from steroid­related ONFH rat femurs were cultured with or without lithium chloride (LiCl). BMMSCs obtained from normal rat femurs were cultured as controls. LiCl significantly increased the expression of osteocalcin and Runx2 in the ONFH-BMMSCs during osteogenic induction. The mineralization of ONFH-BMMSCs following osteogenic induction was also enhanced. Furthermore, LiCl exerted anti-adipogenic effects on the ONFH-BMMSCs by inhibiting the expression of peroxisome proliferator-activated receptor γ (PPARγ) and fatty acid binding protein 4 (Fabp4) during adipogenic induction, and decreasing lipid droplet formation at the end of adipogenic induction. These effects of LiCl on the ONFH-BMMSCs were associated with an increased expression of ß-catenin and a decreased expression of phosphorylated GSK-3ß at Tyr-216, and these effects were abolished by treatment with quercetin, an antagonist of the ß-catenin pathway. The normal osteogenic/adipogenic activity of BMMSCs may be impaired in steroid-related ONFH. However, as demonstrated by our findings, LiCl reduces abnormal adipogenic activity and simultaneously increases the osteogenic differentiation of ONFH-BMMSCs by activating the ß-catenin pathway.

Circumferential electrocautery of the patella in primary total knee replacement without patellar replacement: a meta-analysis and systematic review.

The purpose of this meta-analysis and systematic review was to identify and assess whether circumferential electrocautery is useful for improving outcomes after primary total knee replacement(TKR). We searched MEDLINE, EMBASE, PubMed, SpringerLink, Web of Knowledge, OVID CINAHL, OVID EBM and Google Scholar and included articles published through January 2014. A total of 6 articles met the inclusion criteria. Of the 776 cases included in the analysis, 388 cases involved patellar denervation, and 388 cases were designated as the control group. The meta-analysis revealed no significant difference in the incidence of anterior knee pain (AKP, p = 0.18) or in the visual analogue scale score (VAS, p = 0.23) between the two groups. In addition, AKSS Function Score indicated no significant difference between the two groups (p = 0.28). However, the OKS (p = 0.02), patellar score (p = 0.01), AKSS-Knee Score (p = 0.004), range of motion (ROM, p < 0.0001) and WOMAC Score (p = 0.0003) indicated that circumpatellarelectrocautery improved clinical outcomes compared with non-electrocautery. The results indicate that circumferential electrocautery of the patella does not significantly improve AKP compared with non-electrocautery techniques but that circumferential electrocautery significantly improves patients' knee function after surgery. Therefore, we believe that circumferential electrocautery is beneficial to the outcome of primary TKR surgery without patellar replacement.