Decreased angiogenic and increased apoptotic activities of bone microvascular endothelial cells in patients with glucocorticoid-induced osteonecrosis of the femoral head

CHRDL2 activates the PI3K/AKT pathway to ameliorate glucocorticoid-induced damages to bone microvascular endothelial cells (BMECs)

Steroid-induced avascular necrosis of the femoral head (ANFH) is characterized by the death of bone tissues, leading to the impairment of normal reparative processes within micro-fractures in the femoral head. Glucocorticoid (GCs)-induced bone microvascular endothelial cell (BMEC) damage has been reported to contribute to ANFH development. In this study, differentially expressed genes (DEGs) between necrosis of the femoral head (NFH) and normal samples were analyzed based on two sets of online expression profiles, GSE74089 and GSE26316. Chordin-like 2 (CHRDL2) was found to be dramatically downregulated in NFH samples. In GCs-stimulated BMECs, cellular damages were observed alongside CHRDL2 down-regulation. GCs-caused cell viability suppression, cell apoptosis promotion, tubule formation suppression, and cell migration suppression were partially abolished by CHRDL2 overexpression but amplified by CHRDL2 knockdown; consistent trends were observed in GCs-caused alterations in the protein levels of VEGFA, VEGFR2, and BMP-9 levels, and the ratios of Bax/Bcl-2 and cleaved-caspase3/Caspase3. GC stimulation significantly inhibited PI3K and Akt phosphorylation in BMECs, whereas the inhibitor effects of GCs on PI3K and Akt phosphorylation were partially attenuated by CHRDL2 overexpression but further amplified by CHRDL2 knockdown. Moreover, CHRDL2 overexpression caused improvement in GCs-induced damages to BMECs that were partially eliminated by PI3K inhibitor LY294002. In conclusion, CHRDL2 is down-regulated in NFH samples and GCs-stimulated BMECs. CHRDL2 overexpression could improve GCs-caused BMEC apoptosis and dysfunctions, possibly via the PI3K/Akt pathway.

Research progress in the pathogenesis of hormone-induced femoral head necrosis based on microvessels: a systematic review

Hormonal necrosis of the femoral head is caused by long-term use of glucocorticoids and other causes of abnormal bone metabolism, lipid metabolism imbalance and blood microcirculation disorders in the femoral head, resulting in bone trabecular fracture, bone tissue necrosis collapse, and hip dysfunction. It is the most common type of non-traumatic necrosis of the femoral head, and its pathogenesis is complex, while impaired blood circulation is considered to be the key to its occurrence. There are a large number of microvessels in the femoral head, among which H-type vessels play a decisive role in the "angiogenesis and osteogenesis coupling", and thus have an important impact on the occurrence and development of femoral head necrosis. Glucocorticoids can cause blood flow injury of the femoral head mainly through coagulation dysfunction, endothelial dysfunction and impaired angiogenesis. Glucocorticoids may inhibit the formation of H-type vessels by reducing the expression of HIF-1α, PDGF-BB, VGEF and other factors, thus causing damage to the "angiogenesis-osteogenesis coupling" and reducing the ability of necrosis reconstruction and repair of the femoral head. Leads to the occurrence of hormonal femoral head necrosis. Therefore, this paper reviewed the progress in the study of the mechanism of hormone-induced femoral head necrosis based on microvascular blood flow at home and abroad, hoping to provide new ideas for the study of the mechanism of femoral head necrosis and provide references for clinical treatment of femoral head necrosis.

[α2-macroglobulin alleviates glucocorticoid-induced avascular necrosis of the femoral head in mice by promoting proliferation, migration and angiogenesis of vascular endothelial cells]

OBJECTIVE

To explore the mechanism underlying the protective effect of α2-macroglobulin (A2M) against glucocorticoid-induced femoral head necrosis.

METHODS

In a human umbilical vein endothelial cell (HUVEC) model with injuries induced by gradient concentrations of dexamethasone (DEX; 10-8-10-5 mol/L), the protective effects of A2M at 0.05 and 0.1 mg/mL were assessed by examining the changes in cell viability, migration, and capacity of angiogenesis using CCK-8 assay, Transwell and scratch healing assays and angiogenesis assay. The expressions of CD31 and VEGF-A proteins in the treated cells were detected using Western blotting. In BALB/c mouse models of avascular necrosis of the femoral head induced by intramuscular injections of methylprednisolone, the effects of intervention with A2M on femoral trabecular structure, histopathological characteristics, and CD31 expression were examined with Micro-CT, HE staining and immunohistochemical staining.

RESULTS

In cultured HUVECs, DEX treatment significantly reduced cell viability, migration and angiogenic ability in a concentration- and time-dependent manner (P<0.05), and these changes were obviously reversed by treatment with A2M in positive correlation with A2M concentration (P<0.05). DEX significantly reduced the expression of CD31 and VEGF-A proteins in HUVECs, while treatment with A2M restored CD31 and VEGF-A expressions in the cells (P<0.05). The mouse models of femoral head necrosis showed obvious trabecular damages in the femoral head, where a large number of empty lacunae and hypertrophic fat cells could be seen and CD31 expression was significantly decreased (P<0.05). A2M treatment of the mouse models significantly improved trabecular damages, maintained normal bone tissue structures, and increased CD31 expression in the femoral head (P<0.05).

CONCLUSION

A2M promotes proliferation, migration, and angiogenesis of DEX-treated HUVECs and alleviates methylprednisolone-induced femoral head necrosis by improving microcirculation damages and maintaining microcirculation stability in the femoral head.

Analysis of the Potential Angiogenic Mechanisms of BuShenHuoXue Decoction against Osteonecrosis of the Femoral Head Based on Network Pharmacology and Experimental Validation

OBJECTIVE

Osteonecrosis of the femoral head (ONFH) is a common orthopedic disease with a high disability rate. The clinical effect of BuShenHuoXue decoction (BSHX) for ONFH is satisfactory. We aimed to elucidate the potential angiogenic mechanisms of BSHX in a rat femoral osteonecrosis model and bone marrow mesenchymal stem cells (BMSCs).

METHODS

With in vivo experiments, we established the steroid-induced osteonecrosis of the femoral head (SONFH) model using Sprague-Dawley (SD) rats (8-week-old). The rats were randomly divided into five group of 12 rats each and given the corresponding interventions: control, model (gavaged with 0.9% saline), BSHX low-, medium- and high-dose groups (0.132 3, 0.264 6, and 0.529 2 g/mL BSHX solution by gavage). After 12 weeks, haematoxylin and eosin (H&E) staining was preformed to evaluate rat osteonecrosis. the expression of angiogenic factors (CD31, VEGFA, KDR, VWF) in rat femoral head was detected by immunohistochemistry, qPCR and western blotting. In cell experiment, BMSCs were isolated and cultured in the femoral bone marrow cavity of 4-week-old SD rats. BMSCs were randomly divided into eight groups and intervened with different doses of BSHX-containing serum and glucocorticoids: control group (CG); BSHX low-, medium-, and high-dose groups (CG + 0.661 5, 1.323, and 2.646 g/kg BSHX gavage rat serum); dexamethasone (Dex) group; and Dex + BSHX low-, medium-, and high-dose groups (Dex + 0.661 5, 1.323, and 2.646 g/kg BSHX gavaged rat serum), the effects of BSHX-containing serum on the angiogenic capacity of BMSCs were examined by qPCR and Western blotting. A co-culture system of rat aortic endothelial cells (RAOECs) and BMSCs was then established. Migration and angiogenesis of RAOECs were observed using angiogenesis and transwell assay. Identification of potential targets of BSHX against ONFH was obtained using network pharmacology.

RESULTS

BSHX upregulated the expression of CD31, VEGFA, KDR, and VWF in rat femoral head samples and BMSCs (p < 0.05, vs. control group or model group). Different concentrations of BSHX-containing serum significantly ameliorated the inhibition of CD31, VEGFA, KDR and VWF expression by high concentrations of Dex. BSHX-containing serum-induced BMSCs promoted the migration and angiogenesis of RAOECs, reversed to some extent the adverse effect of Dex on microangiogenesis in RAOECs, and increased the number of microangiogenic vessels. Furthermore, we identified VEGFA, COL1A1, COL3A1, and SPP1 as important targets of BSHX against ONFH.

CONCLUSION

BSHX upregulated the expression of angiogenic factors in the femoral head tissue of ONFH model rats and promoted the angiogenic capacity of rat RAOECs and BMSCs. This study provides an important basis for the use of BSHX for ONFH prevention and treatment.

Identification and analysis of mitochondria-related central genes in steroid-induced osteonecrosis of the femoral head, along with drug prediction

Purpose

Steroid-induced osteonecrosis of the femoral head (SONFH) is a refractory orthopedic hip joint disease that primarily affects middle-aged and young individuals. SONFH may be caused by ischemia and hypoxia of the femoral head, where mitochondria play a crucial role in oxidative reactions. Currently, there is limited literature on whether mitochondria are involved in the progression of SONFH. Here, we aim to identify and validate key potential mitochondrial-related genes in SONFH through bioinformatics analysis. This study aims to provide initial evidence that mitochondria play a role in the progression of SONFH and further elucidate the mechanisms of mitochondria in SONFH.

Methods

The GSE123568 mRNA expression profile dataset includes 10 non-SONFH (non-steroid-induced osteonecrosis of the femoral head) samples and 30 SONFH samples. The GSE74089 mRNA expression profile dataset includes 4 healthy samples and 4 samples with ischemic necrosis of the femoral head. Both datasets were downloaded from the Gene Expression Omnibus (GEO) database. The mitochondrial-related genes are derived from MitoCarta3.0, which includes data for all 1136 human genes with high confidence in mitochondrial localization based on integrated proteomics, computational, and microscopy approaches. By intersecting the GSE123568 and GSE74089 datasets with a set of mitochondrial-related genes, we screened for mitochondrial-related genes involved in SONFH. Subsequently, we used the good Samples Genes method in R language to remove outlier genes and samples in the GSE123568 dataset. We further used WGCNA to construct a scale-free co-expression network and selected the hub gene set with the highest connectivity. We then intersected this gene set with the previously identified mitochondrial-related genes to select the genes with the highest correlation. A total of 7 mitochondrial-related genes were selected. Next, we performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis on the selected mitochondrial-related genes using R software. Furthermore, we performed protein network analysis on the differentially expressed proteins encoded by the mitochondrial genes using STRING. We used the GSEA software to group the genes within the gene set in the GSE123568 dataset based on their coordinated changes and evaluate their impact on phenotype changes. Subsequently, we grouped the samples based on the 7 selected mitochondrial-related genes using R software and observed the differences in immune cell infiltration between the groups. Finally, we evaluated the prognostic significance of these features in the two datasets, consisting of a total of 48 samples, by integrating disease status and the 7 gene features using the cox method in the survival R package. We performed ROC analysis using the roc function in the pROC package and evaluated the AUC and confidence intervals using the ci function to obtain the final AUC results.

Results

Identification and analysis of 7 intersecting DEGs (differentially expressed genes) were obtained among peripheral blood, cartilage samples, hub genes, and mitochondrial-related genes. These 7 DEGs include FTH1, LACTB, PDK3, RAB5IF, SOD2, and SQOR, all of which are upregulated genes with no intersection in the downregulated gene set. Subsequently, GO and KEGG pathway enrichment analysis revealed that the upregulated DEGs are primarily involved in processes such as oxidative stress, release of cytochrome C from mitochondria, negative regulation of intrinsic apoptotic signaling pathway, cell apoptosis, mitochondrial metabolism, p53 signaling pathway, and NK cell-mediated cytotoxicity. GSEA also revealed enriched pathways associated with hub genes. Finally, the diagnostic value of these key genes for hormone-related ischemic necrosis of the femoral head (SONFH) was confirmed using ROC curves.

Conclusion

BID, FTH1, LACTB, PDK3, RAB5IF, SOD2, and SQOR may serve as potential diagnostic mitochondrial-related biomarkers for SONFH. Additionally, they hold research value in investigating the involvement of mitochondria in the pathogenesis of ischemic necrosis of the femoral head.

Exosomes from bone marrow mesenchymal stem cells ameliorate glucocorticoid-induced osteonecrosis of femoral head by transferring microRNA-210 into bone microvascular endothelial cells

OBJECTIVES

Bone microvascular endothelial cells (BMECs) played an important role in the pathogenesis of glucocorticoid-induced osteonecrosis of femoral head (GCS-ONFH), and exosomes derived from bone marrow mesenchymal stem cells (BMSC-Exos) may provide an effective treatment. This study aimed to evaluate the effects of BMSC-Exos and internal microRNA-210-3p (miRNA-210) on GCS-ONFH in an in vitro hydrocortisone-induced BMECs injury model and an in vivo rat GCS-ONFH model.

METHODS

BMECs, BMSCs and BMSC-Exos were isolated and validated. BMECs after the treatment of hydrocortisone were cocultured with different concentrations of BMSC-Exos, then proliferation, migration, apoptosis and angiogenesis of BMECs were evaluated by CCK-8, Annexin V-FITC/PI, cell scratch and tube formation assays. BMSCs were transfected with miRNA-210 mimics and miRNA-210 inhibitors, then BMSC-ExosmiRNA-210 mimic and BMSC-ExosmiRNA-210 inhibitor secreted from such cells were collected. The differences between BMSC-Exos, BMSC-ExosmiRNA-210 mimic and BMSC-ExosmiRNA-210 inhibitor in protecting BMECs against GCS treatment were analyzed by methods mentioned above. Intramuscular injections of methylprednisolone were performed on Sprague-Dawley rats to establish an animal model of GCS-ONFH, then tail intravenous injections of BMSC-Exos, BMSC-ExosmiRNA-210 mimic or BMSC-ExosmiRNA-210 inhibitor were conducted after methylprednisolone injection. Histological and immunofluorescence staining and micro-CT were performed to evaluate the effects of BMSC-Exos and internal miRNA-210 on the in vivo GCS-ONFH model.

RESULTS

Different concentrations of BMSC-Exos, especially high concentration of BMSC-Exos, could enhance the proliferation, migration and angiogenesis ability and reduce the apoptosis rates of BMECs treated with GCS. Compared with BMSC-Exos, BMSC-ExosmiRNA-210 mimic could further enhance the proliferation, migration and angiogenesis ability and reduce the apoptosis rates of BMECs, while BMECs in the GCS + BMSC-ExosmiRNA-210 inhibitor group showed reduced proliferation, migration and angiogenesis ability and higher apoptosis rates. In the rat GCS-ONFH model, BMSC-Exos, especially BMSC-ExosmiRNA-210 mimic, could increase microvascular density and enhance bone remodeling of femoral heads.

CONCLUSIONS

BMSC-Exos containing miRNA-210 could serve as potential therapeutics for protecting BMECs and ameliorating the progression of GCS-ONFH.

Erythropoietin suppresses osteoblast apoptosis and ameliorates steroid-induced necrosis of the femoral head in rats by inhibition of STAT1-caspase 3 signaling pathway

BACKGROUND

Steroid-induced avascular necrosis of the femoral head (SANFH) is characterized by osteoblast apoptosis, leading to a loss of bone structure and impaired hip joint function. It has been demonstrated that erythropoietin (EPO) performs a number of biological roles.

OBJECTIVE

We examined the effects of EPO on SANFH and its regulation of the STAT1-caspase 3 signaling pathway.

METHOD

In vitro, osteoblasts were treated with dexamethasone (Dex) or EPO. We identified the cytotoxicity of EPO by CCK-8, the protein expression of P-STAT1, cleaved-caspase9, cleaved-caspase3, Bcl-2, BAX, and cytochrome c by Western blotting, and evaluated the apoptosis of osteoblasts by flow cytometry. In vivo, we analyzed the protective effect of EPO against SANFH by hematoxylin and eosin (H&E), Immunohistochemical staining, and Micro-computed tomography (CT).

RESULTS

In vitro, EPO had no apparent toxic effect on osteoblasts. In Dex-stimulated cells, EPO therapy lowered the protein expression of BAX, cytochrome c, p-STAT1, cleaved-caspase9, and cleaved-caspase3 while increasing the expression of Bcl-2. EPO can alleviate the apoptosis induced by Dex. In vivo, EPO can lower the percentage of empty bone lacunae in SANFH rats.

CONCLUSION

The present study shows that EPO conferred beneficial effects in rats with SANFH by inhibiting STAT1-caspase 3 signaling, suggesting that EPO may be developed as a treatment for SANFH.

Establishment of the multi-component bone-on-a-chip: to explore therapeutic potential of DNA aptamers on endothelial cells

Background: Despite great efforts to develop microvascular bone chips in previous studies, current bone chips still lacked multi-component of human-derived cells close to human bone tissue. Bone microvascular endothelial cells (BMECs) were demonstrated to be closely related to the glucocorticoid (GC)-induced osteonecrosis of the femoral head (ONFH). Tumor necrosis factor-alpha (TNF-α) aptamer has been proved to bind to its receptor and block cascade activities. Objective: There are two main objectives in this study: 1) to establish a multi-component bone-on-a-chip within the microfluidic system in vitro, 2) to explore the therapeutic potential of TNF-α aptamer on BMECs in the GC-induced ONFH model. Methods: Histological features of clinical samples were analyzed before BMECs isolation. The functional bone-on-a-chip consists of the vascular channel, stromal channel and structure channel. GC-induced ONFH model was established based on the multi-component of human-derived cells. Truncation and dimerization were performed on a previously reported DNA aptamer (VR11). BMECs apoptosis, cytoskeleton and angiogenesis status in the ONFH model were observed by the TUNEL staining and confocal microscope. Results: The multi-component of BMECs, human embryonic lung fibroblasts and hydroxyapatite were cultured within the microfluidic bone-on-a-chip. TNF-α was found up-regulated in the necrotic regions of femoral heads in clinical samples and similar results were re-confirmed in the ONFH model established in the microfluidic platform by detecting cell metabolites. Molecular docking simulations indicated that the truncated TNF-α aptamer could improve the aptamer-protein interactions. Further results from the TUNEL staining and confocal microscopy showed that the truncated aptamer could protect BMECs from apoptosis and alleviate GC-induced damages to cytoskeleton and vascularization. Conclusion: In summary, a microfluidic multi-component bone-on-a-chip was established with 'off-chip' analysis of cell metabolism. GC-induced ONFH model was achieved based on the platform. Our findings provided initial evidence on the possible potentials of TNF-α aptamer as a new type of TNF-α inhibitor for patients with ONFH.

Connexin43 overexpression promotes bone regeneration by osteogenesis and angiogenesis in rat glucocorticoid-induced osteonecrosis of the femoral head

Glucocorticoids induced osteonecrosis of the femoral head (GIONFH) is a devastating orthopedic disease. Previous studies suggested that connexin43 is involved in the process of osteogenesis and angiogenesis. However, the role of Cx43 potentiates in the osteogenesis and angiogenesis of bone marrow-derived stromal stem cells (BMSCs) in GIONFH is still not investigated. In this study, BMSCs were isolated and transfected with green fluorescent protein or the fusion gene encoding GFP and Cx43. The osteogenic differentiation of BMSCs were detected after transfected with Cx43. In addition, the migration abilities and angiogenesis of human umbilical vein endothelial cells (HUVECs) were been detected after induced by transfected BMSCs supernatants in vitro. Finally, we established GC-ONFH rat model, then, a certain amount of transfected or controlled BMSCs were injected into the tibia of the rats. Immunohistological staining and micro-CT scanning results showed that the transplanted experiment group had significantly promoted more bone regeneration and vessel volume when compared with the effects of the negative or control groups. This study demonstrated for the first time that the Cx43 overexpression in BMSCs could promote bone regeneration as seen in the osteogenesis and angiogenesis process, suggesting that Cx43 may serve as a therapeutic gene target for GIONFH treatment.

Glucocorticoid-induced thrombotic microangiopathy in paroxysmal nocturnal hemoglobinuria: A case report and review of literature

BACKGROUND

Thrombotic microangiopathy (TMA) is a group of disorders that converge on excessive platelet aggregation in the microvasculature, leading to consumptive thrombocytopenia, microangiopathic hemolysis and ischemic end-organ dysfunction. In predisposed patients, TMA can be triggered by many environmental factors. Glucocorticoids (GCs) can compromise the vascular endothelium. However, GC-associated TMA has rarely been reported, which may be due to the lack of awareness of clinicians. Given the high frequency of thrombocytopenia during GC treatment, particular attention should be given to this potentially fatal complication.

CASE SUMMARY

An elderly Chinese man had a 12-year history of aplastic anemia (AA) and a 3-year history of paroxysmal nocturnal hemoglobinuria (PNH). Three months earlier, methylprednisolone treatment was initiated at 8 mg/d and increased to 20 mg/d to alleviate complement-mediated hemolysis. Following GC treatment, his platelet counts and hemoglobin levels rapidly decreased. After admission to our hospital, the dose of methylprednisolone was increased to 60 mg/d in an attempt to enhance the suppressive effect. However, increasing the GC dose did not alleviate hemolysis, and his cytopenia worsened. Morphological evaluation of the marrow smears revealed increased cellularity with an increased percentage of erythroid progenitors without evident dysplasia. Cluster of differentiation (CD)55 and CD59 expression was significantly decreased on erythrocytes and granulocytes. In the following days, platelet transfusion was required due to severe thrombocytopenia. Observation of platelet transfusion refractoriness indicated that the exacerbated cytopenia may have been caused by the development of TMA due to GC treatment because the transfused platelet concentrates had no defects in glycosylphosphatidylinositol-anchored proteins. We examined blood smears and found a small number of schistocytes, dacryocytes, acanthocytes and target cells. Discontinuation of GC treatment resulted in rapidly increased platelet counts and steady increases in hemoglobin levels. The patient’s platelet counts and hemoglobin levels returned to the levels prior to GC treatment 4 weeks after GC discontinuation.

CONCLUSION

GCs can drive TMA episodes. When thrombocytopenia occurs during GC treatment, TMA should be considered, and GCs should be discontinued.

Emerging role of mesenchymal stem/stromal cells (MSCs) and MSCs-derived exosomes in bone- and joint-associated musculoskeletal disorders: a new frontier

Exosomes are membranous vesicles with a 30 to 150 nm diameter secreted by mesenchymal stem/stromal cells (MSCs) and other cells, such as immune cells and cancer cells. Exosomes convey proteins, bioactive lipids, and genetic components to recipient cells, such as microRNAs (miRNAs). Consequently, they have been implicated in regulating intercellular communication mediators under physiological and pathological circumstances. Exosomes therapy as a cell-free approach bypasses many concerns regarding the therapeutic application of stem/stromal cells, including undesirable proliferation, heterogeneity, and immunogenic effects. Indeed, exosomes have become a promising strategy to treat human diseases, particularly bone- and joint-associated musculoskeletal disorders, because of their characteristics, such as potentiated stability in circulation, biocompatibility, low immunogenicity, and toxicity. In this light, a diversity of studies have indicated that inhibiting inflammation, inducing angiogenesis, provoking osteoblast and chondrocyte proliferation and migration, and negative regulation of matrix-degrading enzymes result in bone and cartilage recovery upon administration of MSCs-derived exosomes. Notwithstanding, insufficient quantity of isolated exosomes, lack of reliable potency test, and exosomes heterogeneity hurdle their application in clinics. Herein, we will deliver an outline respecting the advantages of MSCs-derived exosomes-based therapy in common bone- and joint-associated musculoskeletal disorders. Moreover, we will have a glimpse the underlying mechanism behind the MSCs-elicited therapeutic merits in these conditions.

Advances in experimental models of osteonecrosis of the femoral head

Background

Osteonecrosis of the femoral head (ONFH) is a devastating disease affecting young adults, resulting in significant pain, articular surface collapse, and disabling dysfunction. ONFH can be divided into two broad categories: traumatic and non-traumatic. It has been established that ONFH results from an inadequate blood supply that causes the death of osteocytes and bone marrow cells. Nonetheless, the precise mechanism of ONFH remains to be elucidated. In this regard, preclinical animal and cell models to study ONFH have been established to assess the efficacy of various modalities for preventing and treating ONFH. Nevertheless, it should be borne in mind that many models do not share the same physiologic and metabolic characteristics as humans. Therefore, it is necessary to establish a reproducible model that better mimics human disease.

Methods

We systematically reviewed the literatures in regard to ONFH experimental models over the past 30 years. The search was performed in PubMed and Web of Science. Original animal, cell studies with available full-text were included. This review summarizes different methods for developing animal and cell experimental models of ONFH. The advantages, disadvantages and success rates of ONFH models are also discussed. Finally, we provide experimental ONFH model schemes as a reference.

Results

According to the recent literatures, animal models of ONFH include traumatic, non-traumatic and traumatic combined with non-traumatic models. Most researchers prefer to use small animals to establish non-traumatic ONFH models. Indeed, small animal-based non-traumatic ONFH modeling can more easily meet ethical requirements with large samples. Otherwise, gradient concentration or a particular concentration of steroids to induce MSCs or EPCs, through which researchers can develop cell models to study ONFH.

Conclusions

Glucocorticoids in combination with LPS to induce ONFH animal models, which can guarantee a success rate of more than 60% in large samples. Traumatic vascular deprivation combines with non-traumatic steroids to induce ONFH, obtaining success rates ranging from 80% to 100%. However, animals that undergo vascular deprivation surgery may not survive the glucocorticoid induction process. As for cell models, 10-6mol/L Dexamethasone (Dex) to treat bone marrow stem cells, which is optimal for establishing cell models to study ONFH.

The translational potential of this article

This review aims to summarize recent development in experimental models of ONFH and recommended the modeling schemes to verify new models, mechanisms, drugs, surgeries, and biomaterials of ONFH to contribute to the prevention and treatment of ONFH.

Glucocorticoid induced bone disorders in children: Research progress in treatment mechanisms

Long-term or supra-physiological dose of glucocorticoid (GC) application in clinic can lead to impaired bone growth and osteoporosis. The side effects of GC on the skeletal system are particularly serious in growing children, potentially causing growth retardation or even osteoporotic fractures. Children's bone growth is dependent on endochondral ossification of growth plate chondrocytes, and excessive GC can hinder the development of growth plate and longitudinal bone growth. Despite the availability of drugs for treating osteoporosis, they have failed to effectively prevent or treat longitudinal bone growth and development disorders caused by GCs. As of now, there is no specific drug to mitigate these severe side effects. Traditional Chinese Medicine shows potential as an alternative to the current treatments by eliminating the side effects of GC. In summary, this article comprehensively reviews the research frontiers concerning growth and development disorders resulting from supra-physiological levels of GC and discusses the future research and treatment directions for optimizing steroid therapy. This article may also provide theoretical and experimental insight into the research and development of novel drugs to prevent GC-related side effects.

[Protective effect of Kaempferol on endothelial cell injury in glucocorticoid induced osteonecrosis of the femoral head]

Objective

To explore the effect of Kaempferol on bone microvascular endothelial cells (BMECs) in glucocorticoid induced osteonecrosis of the femoral head (GIONFH) in vitro.

Methods

BMECs were isolated from cancellous bone of femoral head or femoral neck donated voluntarily by patients with femoral neck fracture. BMECs were identified by von Willebrand factor and CD31 immunofluorescence staining and tube formation assay. The cell counting kit 8 (CCK-8) assay was used to screen the optimal concentration and the time point of dexamethasone (Dex) to inhibit the cell activity and the optimal concentration of Kaempferol to improve the inhibition of Dex. Then the BMECs were divided into 4 groups, namely, the cell group (group A), the cells treated with optimal concentration of Dex group (group B), the cells treated with optimal concentration of Dex+1 μmol/L Kaempferol group (group C), and the cells treated with optimal concentration of Dex+5 μmol/L Kaempferol group (group D). EdU assay, in vitro tube formation assay, TUNEL staining assay, Annexin Ⅴ/propidium iodide (PI) staining assay, Transwell migration assay, scratch healing assay, and Western blot assay were used to detect the effect of Kaempferol on the proliferation, tube formation, apoptosis, migration, and protein expression of BMECs treated with Dex.

Results

The cultured cells were identified as BMECs. CCK-8 assay showed that the optimal concentration and the time point of Dex to inhibit cell activity was 300 μmol/L for 24 hours, and the optimal concentration of Kaempferol to improve the inhibitory activity of Dex was 1 μmol/L. EdU and tube formation assays showed that the cell proliferation rate, tube length, and number of branch points were significantly lower in groups B-D than in group A, and in groups B and D than in group C ( P<0.05). TUNEL and Annexin V/PI staining assays showed that the rates of TUNEL positive cells and apoptotic cells were significantly higher in groups B-D than in group A, and in groups B and D than in group C ( P<0.05). Scratch healing assay and Transwell migration assay showed that the scratch healing rate and the number of migration cells were significantly lower in groups B-D than in group A, and in groups B and D than in group C ( P<0.05). Western blot assay demonstrated that the relative expressions of Cleaved Caspase-3 and Bax proteins were significantly higher in groups B-D than in group A, and in groups B and D than in group C ( P<0.05); the relative expressions of matrix metalloproteinase 2, Cyclin D1, Cyclin E1, VEGFA, and Bcl2 proteins were significantly lower in groups B-D than in group A, and in groups B and D than in group C ( P<0.05).

Conclusion

Kaempferol can alleviate the damage and dysfunction of BMECs in GIONFH.

Ginkgo biloba L. extract prevents steroid-induced necrosis of the femoral head by rescuing apoptosis and dysfunction in vascular endothelial cells via the PI3K/AKT/eNOS pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Ginkgo biloba L. extract (EGb) is one of the world's most extensively used herbal medicines. Due to the diverse pharmacological properties of EGb, it has been used in the treatment of neurological illnesses, as well as cardiovascular and cerebrovascular ailments. However, the effect and pharmacological mechanism of EGb on steroid-induced necrosis of the femoral head (SINFH) are still unclear.

AIM OF THE STUDY

SINFH remains a challenging problem in orthopedics. Previous investigations have shown that EGb has the potential to reduce the occurrence of SINFH. The goal was to determine the effect and mechanism of EGb in preventing SINFH by inhibiting apoptosis and improving vascular endothelial cells (VECs) functions.

MATERIALS AND METHODS

CCK-8, nitric oxide (NO) production and flow cytometry were used to determine the cell apoptosis and function. The scratch and angiogenesis tests assessed migration and tube formation. Western blot analysis detected the expressions of apoptosis-related proteins and PI3K/AKT/eNOS pathway-related proteins. Apoptosis and angiogenesis were also detected treated with the inhibitors. A mouse model of SINFH was established. Paraffin section was used to determine the necrotic pathology and apoptosis. Vessels in the femoral heads were assessed by immunofluorescence staining.

RESULTS

When stimulated by methylprednisolone (MPS), cell viability, NO generation and tube formation were decreased, the apoptotic rate increased. Simultaneously, MPS decreased the expression levels of p-PI3K, p-AKT, and p-eNOS. EGb increased the expression levels of these proteins, restrained apoptosis, and restored cell functions. The addition of the inhibitors decreased anti-apoptotic effect and angiogenesis. In addition, when compared to the model mice, there were fewer empty lacunae and normal trabecular arrangement after taking different doses of EGb. The protective effect was also confirmed by the vascular quantitative analysis in vivo.

CONCLUSION

This study established that EGb increased endothelial cell activity and inhibited apoptosis and function loss induced by MPS, elucidating the effect and molecular mechanism of EGb on early SINFH.

Huogu injection alleviates SONFH by regulating adipogenic differentiation of BMSCs via targeting the miR-34c-5p/MDM4 pathway

Although the precise pathogenesis of steroid-induced osteonecrosis of femoral head (SONFH) is not yet fully understood, evidence shows miRNAs-mediated posttranscription control directs the adipogenesis of bone marrow mesenchymal stem cells (BMSCs) and plays a pivotal role in the SONFH processes. Huogu injection formulated according to traditional Chinese medicine (TCM) theory has been used to treat SONFH by intra-articular injection. In this study, we asked whether the therapeutic effects of Huogu injection might depend on the inhibition of adipogenic differentiation of BMSCs, and if so, the pathway might be a therapeutic target to promote bone repair. Consequently, miR-34c-5p was upregulated in the dexamethasone (DEX)-treated BMSCs and might participate in the adipogenesis of BMSCs. TargetScan database and the luciferase reporter assay showed miR-34c-5p targeted on the MDM4 and negatively regulated its expression. Huogu injection in vitro inhibited the adipogenesis in the DEX-treated BMSCs by inhibiting the expression levels of PPARγ and C/EBPα, as well as reducing miR-34c-5p to prevent the degradation of MDM4. Moreover, miR-34c-5p mimic or MDM4 knockdown using shRNA neutralized the anti-adipogenesis of Huogu injection in BMSCs. In vivo, the results of X-ray imaging confirmed that Huogu injection alleviated the bone loss in rat SONFH. Consistent with results in vitro, Huogu injection reduced the lipid accumulation, removed the suppression of MDM4 by downregulating the expression of miR-34c-5p, and inhibited the expression of C/EBPα and PPARγ in bone tissues. When the lentivirus encoding miR-34c-5p was conducted by intra-articular injection, the overexpression of miR-34c-5p antagonized the therapeutic effects of Huogu injection. Our results underline the critical importance of the miR-34c-5p/MDM4 pathway in regulating the adipogenic outcome of BMSCs, suggesting the miR-34c-5p as a potentially effective therapeutic target in SONFH. These results further reinforce the potential of Huogu injection as an alternative approach in SONFH.

Research Progress on Exosomes in Osteonecrosis of the Femoral Head

Osteonecrosis of the femoral head (ONFH) is a progressive disease that often necessitates hip replacement if hip preservation therapy fails. ONFH places a heavy economic burden and severe psychological pressure on patients. At present, ONFH is treated by either surgical or non‐surgical methods. In clinical practice, stem cells combined with surgery has achieved some positive results, but many problems remain to be resolved. Exosomes are small vesicles of 30–150 nm, which are rich in various nucleic acids, proteins, and small molecules depending on the cells from which they are derived. A growing number of studies have found that exosomes play an important role in tissue damage repair. In comparison with stem cells, exosomes have lower immunogenicity. Also, exosomes can promote cell proliferation and inhibit tumor growth. In addition, exosomes can also be used as natural carriers of drugs. Many studies have shown that exosomes have therapeutic effects in hormone‐induced ONFH. Exosomes have the effect of promoting vascular regeneration and show good application prospects in ONFH. Here, we present a review of studies on the application of exosomes in ONFH to provide a reference for future research.

Vitamin B2 Prevents Glucocorticoid-Caused Damage of Blood Vessels in Osteonecrosis of the Femoral Head

Osteonecrosis of the femoral head (ONFH) is a disorder that can cause collapse of the femoral head. The damage and dysfunction of femoral head microvascular endothelial cells are related to the pathogenesis of glucocorticoid-induced ONFH. Reports suggest that vitamin B₂ can promote osteoblast differentiation and prevent low bone mineral density and prevent reperfusion oxidative injury. To explore the effect and possible molecular mechanism of vitamin B₂ on the ONFH and Human Umbilical Vein Endothelial Cells (HUVECs), we performed a rat model of ONFH by dexamethasone. The rats were randomly divided into four groups: control group, vitamin B₂ group, dexamethasone group, and dexamethasone combined with vitamin B₂ treatment group. HUVECs were used to further prove the role and mechanism of vitamin B₂ in vitro. In patients, according to immunohistochemical and qRT-PCR of the femoral head, the angiogenic capacity of the ONFH femoral head is compromised. In vivo, it showed that vitamin B₂ could inhibit glucocorticoid-induced ONFH-like changes in rats by suppressing cell apoptosis, promoting the regeneration of blood vessels, and increasing bone mass. According to in vitro results, vitamin B₂ could induce the migration of HUVECs, enhance the expression of angiogenesis-related factors, and inhibit glucocorticoid-induced apoptosis. The underlying mechanism may be that vitamin B₂ activates the PI3K signaling pathway. Vitamin B₂ alleviated dexamethasone-induced ONFH, and vitamin B₂ could promote the proliferation and migration of HUVECs and inhibit their apoptosis by activating the PI3K/Akt signaling pathway. Vitamin B₂ may be a potentially effective treatment for ONFH.

Steroid-Induced Osteonecrosis of the Femoral Head: Novel Insight Into the Roles of Bone Endothelial Cells in Pathogenesis and Treatment

Steroid-induced osteonecrosis of the femoral head (SONFH) is a disease characterized by the collapse of the femoral head. SONFH occurs due to the overuse of glucocorticoids (GCs) in patients with immune-related diseases. Among various pathogenesis proposed, the mechanism related to impaired blood vessels is gradually becoming the most convincing hypothesis. Bone endothelial cells including bone microvascular endothelial cells (BMECs) and endothelial progenitor cells (EPCs) play a crucial role in the maintenance of vascular homeostasis. Therefore, bone endothelial cells are key regulators in the occurrence and progression of SONFH. Impaired angiogenesis, abnormal apoptosis, thrombosis and fat embolism caused by the dysfunctions of bone endothelial cells are considered to be the pathogenesis of SONFH. In addition, even with high disability rates, SONFH lacks effective therapeutic approach. Icariin (ICA, a flavonoid extracted from Epimedii Herba), pravastatin, and VO-OHpic (a potent inhibitor of PTEN) are candidate reagents to prevent and treat SONFH through improving above pathological processes. However, these reagents are still in the preclinical stage and will not be widely used temporarily. In this case, bone tissue engineering represented by co-transplantation of bone endothelial cells and bone marrow mesenchymal stem cells (BMSCs) may be another feasible therapeutic strategy.

Cell therapy for osteonecrosis of femoral head and joint preservation

Osteonecrosis of femoral head (ONFH) is a disease of the femoral head and can cause femoral head collapse and arthritis. This can lead to pain and gait disorders. ONFH has various risk factors, it is often progressive, and if untreated results in secondary osteo-arthritis. Biological therapy makes use of bone marrow concentrate, cultured osteoblast and mesenchymal stem cell (MSC) obtained from various sources. These are often used in conjunction with core decompression surgery. In this review article, we discuss the current status of cell therapy and its limitations. We also present the future development of biological approach to treat ONFH.

A Network Pharmacology and Molecular Docking Strategy to Explore Potential Targets and Mechanisms Underlying the Effect of Curcumin on Osteonecrosis of the Femoral Head in Systemic Lupus Erythematosus

Background

Systemic lupus erythematosus (SLE) is a refractory immune disease, which is often complicated with osteonecrosis of the femoral head (ONFH). Curcumin, the most active ingredient of Curcuma longa with a variety of biological activities, has wide effects on the body system. The study is aimed at exploring the potential therapeutic targets underlying the effect of curcumin on SLE-ONFH by utilizing a network pharmacology approach and molecular docking strategy.

Methods

Curcumin and its drug targets were identified using network analysis. First, the Swiss target prediction, GeneCards, and OMIM databases were mined for information relevant to the prediction of curcumin targets and SLE-ONFH-related targets. Second, the curcumin target gene, SLE-ONFH shared gene, and curcumin-SLE-ONFH target gene networks were created in Cytoscape software followed by collecting the candidate targets of each component by R software. Third, the targets and enriched pathways were examined by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Eventually, a gene-pathway network was constructed and visualized by Cytoscape software; key potential central targets were verified and checked by molecular docking and literature review.

Results

201 potential targets of curcumin and 170 related targets involved in SLE-ONFH were subjected to network analysis, and the 36 intersection targets indicated the potential targets of curcumin for the treatment of SLE-ONFH. Additionally, for getting more comprehensive and accurate candidate genes, the 36 potential targets were determined to be analyzed by network topology and 285 candidate genes were obtained finally. The top 20 biological processes, cellular components, and molecular functions were identified, when corrected by a P value ≤ 0.05. 20 related signaling pathways were identified by KEGG analysis, when corrected according to a Bonferroni P value ≤ 0.05. Molecular docking showed that the top three genes (TP53, IL6, VEGFA) have good binding force with curcumin; combined with literature review, some other genes such as TNF, CCND1, CASP3, and MMP9 were also identified.

Conclusion

The present study explored the potential targets and signaling pathways of curcumin against SLE-ONFH, which could provide a better understanding of its effects in terms of regulating cell cycle, angiogenesis, immunosuppression, inflammation, and bone destruction.

CircCDR1as Suppresses Bone Microvascular Endothelial Cell Activity and Angiogenesis Through Targeting miR-135b/ FIH-1 Axis

Objective

The current study investigated the role of CircCDR1as on angiogenesis of bone microvascular endothelial cells (BMECs) isolated from non‐traumatic ONFH.

Methods

Forty corticosteroid‐induced ONFH patients received THA were enrolled in our study. Expressions of CircCDR1as, miR‐135b, and FIH‐1 were detected by qRT‐PCR in affected necrosis tissue and non‐affected normal tissue. Bone microvascular endothelial cells (BMEC) were isolated from six patients and treated with 0.1 mg/mL hydrocortisone to establish a GC‐damaged model of BMECs. Circ CDR1as plasmid and miR‐135b mimic were transfected into BMECs. BMEC proliferation was assessed using MTT assays. The migration ability of cells was detected by scratch‐wound assays. Matrigel assay was performed to detect angiogenesis in vitro. Western blot assay was used to detect HIF‐1α, VEGF, and FIH‐1 expressions. FISH, RNA pull down, RIP, and luciferase assay were carried out to determine the interaction of CircCDR1as, miR‐135b, and FIH‐1.

Results

CircCDR1as was upregulated(2.02 ± 0.30 vs. 1.00 ± 0.10,P < 0.001) whereas miR‐135b was downregulated (0.55 ± 0.12 vs. 1.00 ± 0.10,P < 0.001) in affected tissues than in non‐affected tissues. Expression of CircCDR1as and FIH‐1 were negatively associated with miR‐135b in affected tissues (CircCDR1as with miR‐135b: r = −0.506, P < 0.001; FIH‐1 with miR‐135b r = −0.510, P < 0.001). Total blood tubule density was increased when CircCDR1as was silenced compared with NC (P < 0.01 vs. NC). The number of migrated BMECs were significantly increased in CircCDR1as silencing group compared with NC group (P < 0.05 vs. NC). In addition, CircCDR1as plasmids transfection increased the protein expressions of FIH‐1 (P < 0.05 vs. NC) and reduced the HIF‐1α as well as VEGF expression compared with NC group (P < 0.05 vs. NC). FISH, RNA pull down, RIP, and luciferase assay identified that FIH‐1 was a target of miR‐135b and could be modulated by CircCDR1as.

Conclusion

CircCDR1as decreases angiogenesis and proliferation of BMECs by sponging miR‐135b and upregulate FIH‐1.

Percutaneous autologous impaction bone graft for advanced femoral head osteonecrosis: a retrospective observational study of unsatisfactory short-term outcomes

Background

Half of osteonecrosis of the femoral head (ONFH) patients suffer femoral head collapse at initial diagnosis, and more than half are bilaterally affected. This study developed a percutaneous autologous impaction bone graft (IBG) technique as a modification of core decompression (CD). We also summarized the short-term results and treatment efficacy of percutaneous autologous IBG in advanced ONFH.

Methods

Twenty patients (12 males, 8 females) with nontraumatic, postcollapse ONFH except one case underwent CD (10-mm core diameter) and reverse IBG. Radiological changes of the ONFH stage and type were analyzed. Survival analysis using Kaplan–Meier estimates was performed with conversion to total hip arthroplasty (THA) as the endpoint. In addition, the Harris hip score (HHS) and University of California, Los Angeles (UCLA) activity rating scale were evaluated.

Results

Percutaneous autologous IBG was performed successfully, with an average operation time of < 1 h and small blood loss, and 7 patients (35%) needed conversion to THA at an average of 17 months postoperatively. We observed radiological progressive change in 60% of the patients during a mean observation period of 3 years. The mean clinical scores, except data recorded, after THA significantly improved (before vs. after 3 years: UCLA activity score, 3.7 vs. 5.2 [P = 0.014]; HHS, 57.6 vs. 76.5 points [P = 0.005]). In addition, 6 patients showed radiological progression but no clinical deterioration.

Conclusions

Percutaneous autologous IBG was technically simple and minimally invasive, but short-term results were unsatisfactory for advanced ONFH. Indications for this procedure should be carefully examined to improve it in order to enable bone formation.