Identification of potential miRNA biomarkers for traumatic osteonecrosis of femoral head

Traumatic osteonecrosis of femoral head (TONFH) is a common orthopedic disease caused by physical injury in hip. However, the unclear pathogenesis mechanism of TONFH and lacking of simple noninvasive early diagnosis method cause the necessity of hip replacement for most patients with TONFH. In this study, we aimed to identify circulating microRNAs (miRNAs) by integrated bioinformatics analyses as potential biomarker of TONFH. mRNA expression profiles were downloaded from the Gene Expression Omnibus database. Then we combined two miRNA screen methods: Weighted gene co-expression network analysis and fold change based differentially expressed miRNAs analysis. As a result, we identified 14 key miRNAs as potential biomarkers for TONFH. Besides, 302 target genes of these miRNAs were obtained and the miRNA–mRNA interaction network was constructed. Furthermore, the results of Kyoto Encyclopedia of Gene and Genome pathway analysis, Gene Ontology function analysis, protein–protein interaction (PPI) network analysis and PPI network module analysis showed close correlation between these 14 key miRNAs and TONFH. Then we established receiver operating characteristic curves and identified 6-miRNA signature with highly diagnosis value including miR-93-5p (area under the curve [AUC] = 0.93), miR-1324 (AUC = 0.92), miR-4666a-3p (AUC = 0.92), miR-5011-3p (AUC = 0.92), and miR-320a (AUC = 0.89), miR-185-5p (AUC = 0.89). Finally, the results of quantitative real-time polymerase chain reaction confirmed the significantly higher expression of miR-93-5p and miR-320a in the serum of patients with ONFH. These circulating miRNAs could serve as candidate early diagnosis markers and potential treatment targets of TONFH.     

Prediction of femoral head collapse in osteonecrosis

The femoral head deteriorates in osteonecrosis. As a consequence of that, the cortical shell of the femoral head can buckle into the cancellous bone supporting it. In order to examine the buckling scenario we performed numerical analysis of a realistic femoral head model. The analysis included a solution of the hip contact problem, which provided the contact pressure distribution, and subsequent buckling simulation based on the given contact pressure. The contact problem was solved iteratively by approximating the cartilage by a discrete set of unilateral linear springs. The buckling calculations were based on a finite element mesh with brick elements for the cancellous bone and shell elements for the cortical shell. Results of 144 simulations for a variety of geometrical, material, and loading parameters strengthen the buckling scenario. They, particularly, show that the normal cancellous bone serves as a strong supporting foundation for the cortical shell and prevents it from buckling. However, under the development of osteonecrosis the deteriorating cancellous bone is unable to prevent the cortical shell from buckling and the critical pressure decreases with the decreasing Young modulus of the cancellous bone. The local buckling of the cortical shell seems to be the driving force of the progressive fracturing of the femoral head leading to its entire collapse. The buckling analysis provides an additional criterion of the femoral head collapse, the critical contact pressure. The buckling scenario also suggests a new argument in speculating on the femoral head reinforcement. If the entire collapse of the femoral head starts with the buckling of the cortical shell then it is reasonable to place the reinforcement as close to the cortical shell as possible.     

Biomaterial-loaded allograft threaded cage for the treatment of femoral head osteonecrosis in a goat model

The purpose of this study was to evaluate the efficacy of core decompression with a biomaterial-loaded allograft threaded cage (ATC) for the treatment of femoral head osteonecrosis in an established goat model. First, bilateral early-stage osteonecrosis was induced. After core decompression, the remaining goats were randomly divided into three groups: Group A, the goats were left without any treatment; Group B, the goats were treated with implanting a composite of autologous bone and decalcified bone matrix (DBM); Group C, the goats were treated using insertion of ATC loaded with DBM and autogenous bone graft. Then radiographic, histological and biomechanical analysis were taken in each group at 5, 10, and 20 weeks postoperation. In Group A, the classical signs of osteonecrosis of the femoral head were identified 10 weeks after the induction. Twenty weeks later, the density, surface and biomechanical stability of the femoral head were normal in Group C, while an irregular surface and an inhomogeneous microstructure or variation of density/hardness were identified in Group B. The specimens revealed a continuous trabaecular bone structure throughout the cage and extensive bone ingrowth and remodeling in Group C, while fibrous tissue was evident in Group B. Core decompression with a biomaterial loaded ATC almost uniformly delays or arrests the progression of the disease before articular collapse, and it could help to get the balance between bone resorption and new bone formation, strengthen structural mechanics of the femoral head, provide structure support of articular cartilage.     

Circulating microRNA signature of steroid‐induced osteonecrosis of the femoral head

Objectives

Steroid‐induced osteonecrosis of the femoral head (ONFH) is a common orthopaedic disease of which early detection remains clinically challenging. Accumulating evidences indicated that circulating microRNAs (miRNAs) plays vital roles in the development of several bone diseases. However, the association between circulating miRNAs and steroid‐induced ONFH remains elusive.

Materials and methods

miRNA microarray was performed to identify the differentially abundant miRNAs in the serums of systemic lupus erythematosus (SLE) patients with steroid‐induced ONFH as compared with SLE control and healthy control group. We predicted the potential functions of these differentially abundant miRNAs using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses and reconstructed the regulatory networks of miRNA‐mRNA interactions.

Results

Our data indicated that there were 11 differentially abundant miRNAs (2 upregulated and 9 downregulated) between SLE‐ONFH group and healthy control group and 42 differentially abundant miRNAs (14 upregulated and 28 downregulated) between SLE‐ONFH group and SLE control group. We also predicted the potential functions of these differentially abundant miRNAs using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses and reconstructed the regulatory networks of miRNA‐mRNA interactions.

Conclusions

These findings corroborated the idea that circulating miRNAs play significant roles in the development of ONFH and may serve as diagnostic markers and therapeutic targets.     

Identification of candidate biomarkers of brain damage in a mouse model of closed head injury: a metabolomic pilot study

We aim to identify candidate brain biomarkers for, and to elucidate the pathophysiology of closed traumatic brain injury (TBI). Nuclear magnetic resonance (NMR) based metabolomic analysis was performed on the whole brain of mice undergoing TBI using a validated technique. There were 10 TBI mice compared to 8 sham operated controls. A total of 45 metabolites were evaluated. There was a statistically significant alteration in concentrations of 29 metabolites in TBI brains as compared to controls (FDR <0.05). Profound disturbances of several metabolic pathways (FDR <1E-07), including pathways associated with purine, alanine, aspartate and glutamine and glutathione metabolism were observed. Also, a significant elevation in glutamate (the main excitatory neurotransmitter) and depression of GABA (the main inhibitory neurotransmitter) was observed. Four metabolites, ADP, AMP, NAD+, and IMP were the most important indicators of TBI, relative to normal controls. All were elevated in the TBI mice. A combination of these 4 biomarkers produced a perfect predictor of TBI status, AUC (95 % CI) = 1.0 (1.0, 1.0). We also detected significant disturbances in mitochondrial function, energy metabolism, neurotransmitter metabolism and other important biochemical pathways in TBI mouse brains. Further studies to assess the utility of metabolomics to detect and classify the severity of and assess the prognosis of TBI is warranted.     

骨源性细胞因子在激素性股骨头坏死发生发展中的研究进展

股骨头坏死是骨外科常见的难治性疾病,其机制仍有待研究.目前为止,医源性糖皮质激素是非创伤性股骨头坏死的主要原因.激素的长期使用可导致股骨头骨细胞凋亡、血液循环障碍所致缺血缺氧,最终导致股骨头塌陷.激素性股骨头坏死的发生发展与骨组织中细胞直接接触和其间接分泌的细胞因子调控相关.本文综述了骨组织中成骨细胞分泌的核因子κB受...     

Osteocyte-based image analysis for quantitation of histologically apparent femoral head osteonecrosis: application to an emu model

Femoral head osteonecrosis is often characterized histologically by the presence of empty lacunae in the affected bony regions. The shape, size and location of a necrotic lesion influences prognosis, and can, in principle, be quantified by mapping the distribution of empty lacunae within a femoral head. An algorithm is here described that automatically identifies the locations of osteocyte-filled vs. empty lacunae. The algorithm is applied to necrotic lesions surgically induced in the emu, a large bipedal animal model in which osteonecrosis progresses to collapse, as occurs in humans. The animals' femoral heads were harvested at sacrifice, and hematoxylin and eosin-stained histological preparations of the coronal midsections were digitized and image-analyzed. The algorithm's performance in detecting empty lacunae was validated by comparing its results to corresponding assessments by six trained histologists. The percentage of osteocyte-filled lacunae identified by the algorithm vs. by the human readers was statistically indistinguishable.     

Association between MTHFR C677T polymorphism and osteonecrosis of the femoral head: a meta-analysis

The results of studies on association between the C677T polymorphism of the 5,10-methylene-tetrahydrofolate reductase (MTHFR) gene and osteonecrosis of the femoral head (ONFH) are controversial. To derive a more precise estimation of the relationship between the MTHFR C677T polymorphism and ONFH, a meta-analysis was performed. Eight studies on MTHFR C677T association with ONFH were searched up to April 2011, and the genotype frequencies in control group were consistent with Hardy–Weinberg equilibrium. The effect summary odds ratio (OR) and 95% confidence intervals were obtained. Publication bias was tested by funnel plot, Egger’s regression test, and heterogeneity was assessed. Eight studies containing 778 cases and 1,162 controls were included. Heterogeneity was observed (χ ² = 18.58, P = 0.01). Under the random effects model, the common OR was 1.38 (95% CI: 0.92–2.08; P = 0.12). In the subgroup meta-analysis, there was an association between MTHFR C677T polymorphism and ONFH in non-Asian population for CT + TT vs. CC (OR = 1.72; 95% CI: 1.21–2.43; P = 0.002; I ²  = 37.9%, P = 0.17), but not for Asian population (OR = 0.88; 95% CI: 0.66–1.66; P = 0.35; I ²  = 45.4%, P = 0.16). There was heterogeneity between studies and no clear evidence of an association on a worldwide population. When stratifying for the race, this meta-analysis did not provide an evidence of confirming association between MTHFR C677T polymorphism and ONFH. The large sample and well-designed study based on different ethnic groups should be considered in future associated studies to clarify the association of MTHFR C677T polymorphism with ONFH susceptibility.     

Peroxisome proliferator-activated receptor-gamma gene polymorphisms are not associated with osteonecrosis of the femoral head in the Korean population

Osteonecrosis of the femoral head (ONFH) is a multifactorial disease to which certain individuals are more at risk. Altered lipid metabolism is one of the major risk factors for osteonecrosis, especially corticosteroid therapy and alcoholism. Peroxisome Proliferator-Activated Receptor-gamma (PPARgamma) plays a crucial role in differentiation of mesenchymal cells to adipocytes, lipid homeostasis, and bone metabolism. To investigate the possible association between PPARgamma gene variants and susceptibility to ONFH, we genotyped three common polymorphisms (-796A > G, +34C > G[Pro12Ala], and +82466C > T[His477His]) in 448 ONFH patients and 336 control subjects. Genotypes, allele frequencies, and haplotypes of the polymorphisms in the complete set of patients as well as in subgroups by sex or etiology were not significantly different from those in the control group. This suggests that the examined polymorphisms and haplotypes of the PPARgamma gene are unlikely to be associated with susceptibility to ONFH.     

Genetic association of the P-glycoprotein gene ABCB1 polymorphisms with the risk for steroid-induced osteonecrosis of the femoral head in Chinese population

Steroid administration, which is commonly performed for the treatment of autoimmune inflammatory diseases, cancers or organ transplantation, has been a leading cause of nontraumatic osteonecrosis of the femoral head (ONFH). Single nucleotide polymorphisms (SNPs) of the adenosine triphosphate-binding cassette B1 (ABCB1) gene have been demonstrated to be related to steroid-induced ONFH in small sample sizes of Japanese kidney failure and Chinese systemic lupus erythematosus patients. However, there are obvious controversial results in the relationship of ABCB1 gene polymorphisms with steroid-induced ONFH. The aim of this study was to validate the genetic association of ABCB1 polymorphisms with the risk for steroid-induced ONFH in a large cohort of Chinese population. A case–control study was conducted, which included 94 and 106 unrelated patients after steroid administration recruited from 14 provinces in China, respectively. Two SNPs (rs1045642 and rs2032582) within ABCB1 were genotyped using Sequenom MassARRAY system. Multivariate analyses based on clinical information were performed to determine the associations between the SNPs and risk of steroid-induced ONFH. rs1045642 SNP was significantly associated with steroid-induced ONFH group in codominant (P = 0.02), recessive (P = 0.006) and overdominant (P = 0.03) models. However, there were no differences found in genotype frequencies of rs2032582 SNP between controls and patients with steroid-induced ONFH (all P > 0.05). These findings suggested that rs1045642 SNP of ABCB1 may be associated with the risk of steroid-induced ONFH. Thus, it is useful to analyze this polymorphism for identifying high-risk individuals before the administration of steroids.     

Serum metabolomic profiling for patients with adenocarcinoma of the esophagogastric junction

Metabolomics - Through the systematic large-scale profiling of metabolites, metabolomics provides a tool for biomarker discovery and improving disease monitoring, diagnosis, prognosis, and...     

Activation of aldehyde dehydrogenase 2 protects ethanol‐induced osteonecrosis of the femoral head in rat model

ObjectivesOsteonecrosis of the femoral head (ONFH) is a devastating disease characterized by destructive bone structures, enlarged adipocyte accumulation and impaired vascularization. The aldehyde dehydrogenase 2 (ALDH 2) is the limiting enzyme for ethanol metabolism with many physiological functions. The aim was investigated the potential protective role of activated ALDH 2 by Alda‐1 for ethanol‐induced ONFH.Materials and MethodsThe ethanol‐induced ONFH in rat was performed to explore the protective of Alda‐1 by various experimental methods. Subsequently, the effect of Alda‐1 and ethanol on the osteogenic and adipogenic differentiation was investigated via multiple cellular and molecular methods. Finally, the effect of Alda‐1 and ethanol on the neo‐vascularization was detected in Human umbilical vein endothelial cells (HUVECs) and ONFH model.ResultsFirstly, radiographical and pathological measurements indicated that alda‐1 protected ethanol‐induced ONFH. Moreover, ethanol significantly inhibited the proliferation and osteogenic differentiation of BMSCs, whereas Alda‐1 could distinctly rescue it by PI3K/AKT signalling. Secondly, ethanol remarkably promoted the lipid vacuoles formation of BMSCs, while Alda‐1 significantly retarded it on BMSCs by AMPK signalling pathway. Finally, ethanol significantly inhibited proliferation and growth factor level resulting in reduced angiogenesis, whereas Alda‐1 could rescue the effect of ethanol. Additionally, Alda‐1 significantly reduced the occurrence of ONFH and promoted vessel number and distribution in alcoholic ONFH.ConclusionsAlda‐1 activation of ALDH 2 was highly demonstrated to protect ethanol‐induced ONFH by triggering new bone formation, reducing adipogenesis and stimulating vascularization.

Alda‐1 activation of ALDH 2 was highly demonstrated to protect ethanol‐induced ONFH by triggering new bone formation, reducing adipogenesis and stimulating vascularization. Therefore, ALDH 2 may be a potential therapeutic target and small molecule Alda‐1 may be promising pharmacotherapeutic for ONFH in the future.     

Mesenchymal stem cells‐derived and siRNAs‐encapsulated exosomes inhibit osteonecrosis of the femoral head

Osteonecrosis of the femoral head (ONFH) is a progressive, obstinate and disabling disease. At present, the treatment of ONFH is still a global medical problem. We aim to explore the role of bone mesenchymal stem cells (BMSCs)‐derived and siRNAs‐encapsulated exosomes (siRNAs‐encapsulated BMSCexos) in ONFH. We first isolated BMSCexos and screened siRNAs of 6 ONFH‐related genes for siRNAs‐encapsulated BMSCexo. The expression of these 6 ONFH‐related genes in dexamethasone (DXM)‐treated MC3T3‐E1 cell, cell model of ONFH, was detected by RT‐qPCR and Western blot analysis. And then, we performed CCK‐8 assay, angiogenesis assay and HE staining analysis to test the promotion role of the siRNAs‐encapsulated BMSCexo for angiogenesis during ONFH repair. The results suggest that the obtained particles were BMSCexos. The screened effective siRNAs could effectively knock down their expression in VECs. Moreover, siRNAs‐encapsulated BMSCexo could effectively knock down the expression of these genes in VECs. In addition, siRNAs‐encapsulated BMSCexo promote angiogenesis during ONFH repair. In conclusion, we found siRNAs‐encapsulated BMSCexos could promote ONFH repair by angiogenesis, and indicated exosome as the new siRNA carrier is of great significance to improve the efficiency of RNAi.     

Lack of association of MTHFR gene polymorphisms with the risk of osteonecrosis of the femoral head in a Korean population

Some studies have suggested that coagulation disorders may be implicated in osteonecrosis of the femoral head (ONFH). The C677T polymorphism of the 5, 10-methylenetetrahydrofolate reductase (MTHFR) gene has been postulated to be a genetic risk factor for venous thromboembolism and osteonecrosis in Caucasians, but this relationship has not been established in other populations. In this study, we conducted case-control analysis of whether MTHFR polymorphisms are associated with ONFH in Korean patients. Fifteen single nucleotide polymorphisms (SNPs) were selected and genotyped in 443 ONFH patients and 273 control subjects using the TaqMan 5′ allelic discrimination assay. Comparison of ONFH and control subjects using logistic regression models revealed no statistically significant differences in the frequencies of the MTHFR polymorphisms and haplotypes. Further analysis stratified by etiology also showed no association. These results suggest that MTHFR polymorphisms play no significant role in susceptibility to ONFH in the Korean population.     

Association analysis of tissue factor pathway inhibitor polymorphisms and haplotypes with osteonecrosis of the femoral head in the Korean population

Thrombophilia and hypofibrinolysis have been implicated in the pathogenesis of osteonecrosis of the femoral head (ONFH). Tissue factor pathway inhibitor (TFPI), a multivalent protease inhibitor, is an important regulator of the tissue factor-mediated blood coagulation pathway. Mutations of the TFPI gene can increase the risk of thrombin generation and venous thrombosis. The aim of this study was to evaluate the association of TFPI gene polymorphisms with ONFH. All exons and their boundaries of the TFPI gene, including the -1500 bp promoter region, were directly sequenced in 24 Korean individuals and four sequence variants were identified. These four polymorphisms [-51096 G > A (C-399T), -50984A > G (T-287C), + 24999A > G (Int7 -33T > C), + 37339T > A] were genotyped in 474 ONFH patients and 349 control subjects. The association of genotyped SNPs with ONFH was not found in the present study. The haplotype AAAT of TFPI was significantly associated with total, alcohol-induced, and idiopathic ONFH (p = 0.003, 0.021, and 0.007, respectively), and the haplotype GAAT was significantly associated with total and alcohol ONFH (p = 0.022 and 0.009, respectively). In addition, a new SNP + 37339 T > A in the 3'-UTR of the TFPI gene, was found in the Korean population. To date, this study is the first to show that haplotypes of the TFPI gene are associated with an increased susceptibility for ONFH. The results suggest that genetic variations in TFPI may play an important role in the pathogenesis and risk factors of ONFH.