Overactivated autophagy contributes to steroid-induced avascular necrosis of the femoral head

Palliative effect of rotating magnetic field on glucocorticoid-induced osteonecrosis of the femoral head in rats by regulating osteoblast differentiation

With the substantial increase in the overuse of glucocorticoids (GCs) in clinical medicine, the prevalence of glucocorticoid-induced osteonecrosis of the femoral head (GC-ONFH) continues to rise in recent years. However, the optimal treatment for GC-ONFH remains elusive. Rotating magnetic field (RMF), considered as a non-invasive, safe and effective approach, has been proved to have multiple beneficial biological effects including improving bone diseases. To verify the effects of RMF on GC-ONFH, a lipopolysaccharide (LPS) and methylprednisolone (MPS)-induced invivo rat model, and an MPS-induced invitro cell model have been employed. The results demonstrate that RMF alleviated bone mineral loss and femoral head collapse in GC-ONFH rats. Meanwhile, RMF reduced serum lipid levels, attenuated cystic lesions, raised the expression of anti-apoptotic proteins and osteoprotegerin (OPG), while suppressed the expression of pro-apoptotic proteins and nuclear factor receptor activator-κB (RANK) in GC-ONFH rats. Besides, RMF also facilitated the generation of ALP, attenuated apoptosis and inhibits the expression of pro-apoptotic proteins, facilitated the expression of OPG, and inhibited the expression of RANK in MPS-stimulated MC3T3-E1 cells. Thus, this study indicates that RMF can improve GC-ONFH in rat and cell models, suggesting that RMF have the potential in the treatment of clinical GC-ONFH.

A Comprehensive Review on the Importance of Sustainable Synthesized Coinage Metal Nanomaterials and Their Diverse Biomedical Applications

From a historical perspective, coinage metals (CMNMs) are most renowned for their monetary, ornamental, and metallurgical merits; nevertheless, as nanotechnology's potential has only just come to light, their metal nanostructures and uses may be viewed as products of modern science. Notable characteristics of CMNMs include visual, electrical, chemical, and catalytic qualities that depend on shape and size. Due diligence on the creation and synthesis of CMNMs and their possible uses has been greatly promoted by these characteristics. This review focuses on solution-based methods and provides an overview of the latest developments in CMNMs and their bimetallic nanostructures. It discusses a range of synthetic techniques, including conventional procedures and more modern approaches used to enhance functionality by successfully manipulating the CMNMs nanostructure's size, shape, and composition. To help with the design of new nanostructures with improved capabilities in the future, this study offers a brief assessment of the difficulties and potential future directions of these intriguing metal nanostructures. This review focuses on mechanisms and factors influencing the synthesis process, green synthesis, and sustainable synthesis methods. It also discusses the wide range of biological domains in which CMNMs are applied, including antibacterial, antifungal, and anticancer. Researchers will therefore find the appropriateness of both synthesizing and using CMNMS keeping in mind the different levels of environmental effects.

Clinical Characteristics, Current Treatment Options, Potential Mechanisms, Biomarkers, and Therapeutic Targets in Avascular Necrosis of Femoral Head

Avascular necrosis of femoral head (AVNFH) is a debilitating disease of the young, affecting the quality of life significantly and eventually leading to total hip replacement surgery. The disease is diagnosed clinico-radiologically and MRI is the investigation of choice to diagnose the early stages of the disease. There is neither an early biomarker for detection nor is there a permanent cure for the disease and most of the patients are managed with various combinations of surgical and medical management protocols. In this review, we comprehensively address the etiopathogenesis, clinical characteristics, therapeutic procedures, bone characteristics, histopathology, multi-omic studies, finite element modeling, and systems analysis that has been performed in AVNFH. The etiology includes various factors that compromise the blood supply to the femoral head which also includes contributions by environmental and genetic factors. Multi-omic analysis has shown an association of deregulated pathways with the disease. The cell types involved include mesenchymal stem cells, osteoblasts, osteoclasts, endothelial and immune cells. Biochemical, hematological, histopathology, IHC, and other bone remodeling and degradation marker studies have been performed. A systems analysis using multi-omic data sets from published literature was carried out, the relevance of which is discussed to delineate potential mechanisms in etiopathogenesis, diagnosis, and effective management of this debilitating disease.

Lithium prevents glucocorticoid-induced osteonecrosis of the femoral head by regulating autophagy

Autophagy may play an important role in the occurrence and development of glucocorticoid-induced osteonecrosis of the femoral head (GC-ONFH). Lithium is a classical autophagy regulator, and lithium can also activate osteogenic pathways, making it a highly promising therapeutic agent for GC-ONFH. We aimed to evaluate the potential therapeutic effect of lithium on GC-ONFH. For in vitro experiments, primary osteoblasts of rats were used for investigating the underlying mechanism of lithium's protective effect on GC-induced autophagy levels and osteogenic activity dysfunction. For in vivo experiments, a rat model of GC-ONFH was used for evaluating the therapeutic effect of oral lithium on GC-ONFH and underlying mechanism. Findings demonstrated that GC over-activated the autophagy of osteoblasts and reduced their osteogenic activity. Lithium reduced the over-activated autophagy of GC-treated osteoblasts through PI3K/AKT/mTOR signalling pathway and increased their osteogenic activity. Oral lithium reduced the osteonecrosis rates in a rat model of GC-ONFH, and restrained the increased expression of autophagy related proteins in bone tissues through PI3K/AKT/mTOR signalling pathway. In conclusion, lithium can restrain over-activated autophagy by activating PI3K/AKT/mTOR signalling pathway and up-regulate the expression of genes for bone formation both in GC induced osteoblasts and in a rat model of GC-ONFH. Lithium may be a promising therapeutic agent for GC-ONFH. However, the role of autophagy in the pathogenesis of GC-ONFH remains controversial. Studies are still needed to further explore the role of autophagy in the pathogenesis of GC-ONFH, and the efficacy of lithium in the treatment of GC-ONFH and its underlying mechanisms.

Screening and identification of potential key biomarkers for glucocorticoid-induced osteonecrosis of the femoral head

BACKGROUND

Glucocorticoid-induced osteonecrosis of the femoral head (GIONFH) is a common disease in osteoarticular surgery, with a high disability rate, which brings great physical and mental pain and economic burden to patients. Its specific pathogenesis has not been fully demonstrated, and there is a lack of recognized effective biomarkers for earlier detection and prompt treatment. This has become an urgent clinical problem for orthopedic scholars.

MATERIALS AND METHODS

We downloaded the gene expression profile dataset GSE123568 from the Gene Expression Omnibus database, used STRING and Cytoscape to carry out module analysis and built a gene interaction network. The four core genes most related to GIONFH in this network were ultimately found out by precise analysis and animal experiment were then conducted for verification. In this verification process, thirty-six New Zealand white rabbits were randomly divided into blank control group, model group and drug group. Except for the blank control group, the animal model of GIONFH was established by lipopolysaccharide and methylprednisolone, while the drug group was given the lipid-lowering drugs for intervention as planned. The rabbits were taken for magnetic resonance imaging at different stages, and their femoral head specimens were taken for pathological examination, then the expression of target genes in the femoral head specimens of corresponding groups was detected. Validation methods included RT-PCR and pathological examination.

RESULTS

A total of 679 differential genes were selected at first, including 276 up-regulated genes and 403 down-regulated genes. Finally, four genes with the highest degree of correlation were screened. Animal experiment results showed that ASXL1 and BNIP3L were in low expression, while FCGR2A and TYROBP were highly expressed.

CONCLUSION

Through animal experiments, it was confirmed that ASXL1, BNIP3L, FCGR2A and TYROBP screened from the comparative analysis of multiple genes in the database were closely related to GIONFH, which is important for early diagnosis of Glucocorticoid-induced osteonecrosis of the femoral head.

Methylprednisolone Inhibits Autophagy of Vascular Endothelial Cells in Rat Femoral Head Via PI3K/Akt/mTOR Pathway

Objective

To study the relationship between vascular endothelial cells (VEC) and autophagy, and its regulatory mechanism in steroid‐induced avascular necrosis of the femoral head (SANFH).

Methods

In cell experiment, VEC were isolated and cultured from the femoral head of Sprague–Dawley rats and divided into three groups: blank control group (Ctrl), methylprednisolone group (MP), and methylprednisolone+mTOR‐shRNA group (MP + shmTOR). The autophagy formation was observed by transmission electron microscope. The mRNA expression of PI3K, Akt, mTOR, Beclin1 and MAP1LC3 was detected by RT‐PCR and the protein expression was detected by Western blot and immunofluorescence. Expression of the damage marker 6‐keto‐PGF1α was detected by the ELISA method. In vivo experiment, after establishing the model, the grouping method was the same as cell experiment. Autophagosomes were observed by same method, and the expression of related factors was detected by the same method in cell experiment.

Results

In the cell experiment, autophagosomes in the MP group were significantly lower than in the Ctrl group, and the autophagosomes in the MP + shmTOR group were intermediate between two groups (P < 0.05). The mRNA expression levels of PI3K, Akt and mTOR in the MP group were significantly higher than in the Ctrl group, while the MP+ shmTOR group presented intermediate levels between these groups (average gray value were 3837.90, 2996.30, 3005.60, F = 428.64, P < 0.05). MRNA expression levels of Beclin1 and MAP1LC3 in the MP group were significantly lower than that in Ctrl group (P < 0.05). The content of 6‐keto‐PGF1α in the MP + shmTOR group was higher than in the Ctrl group and lower than in the MP group at the evaluated time intervals (average absorbance value were 104.98, 206.83, 145.91, F = 352.83, P < 0.01). In vivo experiment, the content of 6‐Keto‐PGF1α in the hormone group increased as time went on; the mTOR‐si group was higher than that in control group, but lower than that in the hormone group (P < 0.01). The mRNA expressions of Beclin1 and MAP1LC3 in the control group were higher than those in the hormone group, while the mRNA expressions of PI3K, Akt and mTOR were lower than those in the mTOR‐si group (P < 0.05).

Conclusion

The steroid inhibited the physiological protective effect of autophagy on SANFH by increasing the expression of PI3K/Akt/mTOR signaling pathway related factors and decreasing the expression of Beclin1 and MAP1LC3 in the femoral head VEC.

Autophagy in Femoral Head Necrosis of Broilers Bone Metabolism Parameters and Autophagy-Related Gene Expression in Femoral Head Necrosis Induced by Glucocorticoid in Broilers

Objectives: In this study, the influence of methylprednisolone (MP) and 3-methyladenine (3-MA) on chondrocyte autophagy and bone quality were determined to investigate the mechanisms of femoral head necrosis in broilers.

Methods: Chickens were divided into four groups: control, MP, 3-MA, and 3-MA+MP groups. Blood and bone samples were collected for biochemistry assay and bone quality determination. Cartilage was separated from the femoral head for histopathological analysis and gene expression detection.

Results: The results indicated that MP treatment significantly affected blood levels of alkaline phosphatase, high-density lipoprotein, calcium, phosphorus, bone alkaline phosphatase, and osteocalcin in broilers. Additionally, MP treatment significantly increased blood levels of cholesterol, low-density lipoprotein, triglyceride, carboxy-terminal telopeptide of type-I collagen, and tartrate-resistant acid phosphatase 5. MP treatment also significantly decreased the levels of bone parameters compared with these values in controls, inhibited the expression of collagen-2, aggrecan, and mammalian target of rapamycin, and increased the expression of beclin1 and microtubule-associated protein 1 light chain 3, hypoxia-inducible factor 1 alpha, phosphoinositide 3-kinase, protein kinase B and autophagy-related gene 5 of the femoral head. Furthermore, following co-treatment with 3-MA and MP, 3-MA mitigated the effects of MP.

Conclusions: Our findings demonstrated that autophagy may be involved in the pathogenesis of femoral head necrosis induced by MP in broilers, and this study provides new treatment and prevention ideas for femoral head necrosis caused by glucocorticoids.

Gujiansan Ameliorates Avascular Necrosis of the Femoral Head by Regulating Autophagy via the HIF-1α/BNIP3 Pathway

Background

Clinically, the traditional Chinese medicine compound Gujiansan has been widely used in the treatment of steroid-induced avascular necrosis of the femoral head (SANFH). The present study aimed to investigate the mechanisms underlying the therapeutic effect of Gujiansan.

Methods

A rat model of SANFH was established by the injection of dexamethasone (DEX) at a high dosage of 25 mg/kg/d. Then, Gujiansan was intragastrically administered for 2 weeks, 4 weeks, and 8 weeks, and histological examination of the femoral head was performed. The expression levels of related mRNAs and proteins were analyzed by qRT-PCR, Western blotting, and immunohistochemistry, and the levels of bone biochemical markers and cytokines were detected with ELISA kits.

Results

Gujiansan administration ameliorated SANFH and induced the expression of hypoxia-inducible factor-1α (HIF-1α), Bcl-2/adenovirus E1B 19 kDa interacting protein 3 (BNIP3), LC3, and Beclin-1 in the rat model in a dose- and time-dependent manner, and Gujiansan promoted osteocalcin secretion at the femoral head. In addition, Gujiansan increased the levels of bone formation- and bone resorption-specific markers (osteocalcin (OC), bone-specific alkaline phosphatase (BAP), tartrate resistant acid phosphatase-5b (TRACP-5b), N-terminal telopeptides of type I collagen (NTX-1), and C-terminal telopeptide of type I collagen (CTX-1)) and decreased the levels of proinflammatory cytokines (TNF-α, IL-6, and CRP) in a dose- and time-dependent manner.

Conclusions

Gujiansan accelerates the formation of a new bone, promotes the absorption of the damaged bone, inhibits the inflammatory response, induces autophagy of the femoral head via the HIF-1α/BNIP3 pathway, and ultimately ameliorates SANFH.

Effectiveness and safety of traditional Chinese medicine in the treatment of steroid-osteonecrosis of femoral head: A protocol for systematic review and meta-analysis

BACKGROUND

Osteonecrosis of the femoral head (ONFH) is a common refractory disease in orthopedics. Overdose glucocorticoid application is a common trigger for ONFH. Traditional Chinese medicine (TCM), as a treatment for ONFH, has been shown to be effective in treating steroid-induced ONFH (SONFH). However, a systematic review and meta-analysis of them is lacking. We aim to systematically review the effectiveness and safety of TCM in the treatment of SONFH.

METHODS

We will search the following databases: PubMed, Embase, the Cochrane Library, MEDLINE, the Chinese Biomedical Literature Database, China Science and Technology Journal Database, China National Knowledge Infrastructure, and Wanfang Data (since the inception of the databases to the present). In addition, we will look for clinical trial registrations, prospective grey literature, relevant conference papers, and established study reference lists. We will use Review Manager 5.3 software for meta-analysis and heterogeneity assessment. We will evaluate the quality of the evidence using a hierarchy of recommendation assessment, development, and evaluation.

RESULTS

This study will systematically evaluate the efficacy and safety of TCM in the treatment of SONFH.

CONCLUSION

This systematic review to evaluate the effectiveness and safety of TCM in the treatment of SONFH will provide updated evidence for clinical application.

INPLASY REGISTRATION NUMBER

INPLASY202170015.

Effects of osteoblast autophagy on glucocorticoid-induced femoral head necrosis

Objectives

This study aims to explore the mechanism by which osteoblast autophagy participated in glucocorticoid-induced femoral head necrosis (FHN).

Materials and methods

Thirty male specific-pathogen-free C57 mice (age, one month; weighing 20-25 g) were randomly divided into blank control, dexamethasone and rapamycin-dexamethasone groups (n=10). After six weeks of intervention, right femoral head was obtained to observe morphology and to calculate percentage of empty lacunae. MC3T3-E1 cells were randomly divided into normal, dexamethasone, rapamycin and dexamethasone-rapamycin groups, and cultured for 24 h. Microtubule-associated protein 1 light chain 3 (LC3)-I, LC3-II, mammalian target of rapamycin (mTOR) and Beclin-1 protein expressions were detected by Western blot.

Results

In rapamycin-dexamethasone group, some bone trabeculae in medullary cavity ruptured and atrophied, and subchondral bone underwent local necrosis. The total apoptosis rates of dexamethasone and rapamycin-dexamethasone groups surpassed that of blank control group, and the former two groups had significantly different rates (p<0.001). LC3-II/LC3-I of dexamethasone group was lower than those of rapamycin and dexamethasone-rapamycin groups (p<0.001), and the ratio of rapamycin group surpassed that of dexamethasone-rapamycin group (p<0.001). Dexamethasone group had higher mTOR protein expression than those of rapamycin and dexamethasone- rapamycin groups (p<0.001), and the expression of rapamycin group was lower than that of dexamethasone-rapamycin group (p<0.001). The Beclin-1 protein expression of dexamethasone group was lower than those of rapamycin and dexamethasone- rapamycin groups (p<0.001), and the expression of rapamycin group exceeded that of dexamethasone-rapamycin group (p<0.05).

Conclusion

Osteoblast autophagy may play a crucial protective role in dexamethasone-induced FHN. The attenuation of autophagy may be related to the affected expressions of key autophagy regulators mTOR and Beclin-1.

Untargeted metabolomics reveals the effect of lovastatin on steroid-induced necrosis of the femoral head in rabbits

Purpose

Lovastatin is an important medicine and it shows a significant effect against glucocorticoid-induced necrosis of the femoral head. This study aimed to investigate the effect of lovastatin on preventing necrosis of the femoral head of by serum metabolomics strategy.

Methods

Adult healthy adult Japanese white rabbits were divided into three groups: control group, model group, and drug group. The pathologic changes of femoral head were assessed with magnetic resonance imaging and microscope. Metabolomics based on ultra-high performance liquid chromatography tandem mass spectrometry analysis was used to analyze the collected serum sample. Data were analyzed using principal component analysis, partial least squares-discriminate analysis, and orthogonal partial least squares-discriminant analysis. All potential metabolites were identified by comparing with human metabolome database, Metlin database, lipid maps, and chemspider database.

Results

Eleven potential biomarkers were noted and identified as potential biomarkers. The change of biomarkers suggested that lovastatin on preventing necrosis of the femoral head may affect glycerophospholipid metabolism, linoleic acid metabolism, sphingolipid metabolism, alpha-linolenic acid metabolism, pyrimidine metabolism, and arachidonic acid metabolism.

Conclusion

The study suggested that lovastatin could prevent the glucocorticoid-induced necrosis of the femoral head of rabbits. The possible reasons were closely associated with adjusting the lipid metabolism, inhibiting adipogenesis, and delaying the osteocyte apoptosis.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s13018-020-02026-5.

A metabolomic study on early detection of steroid-induced avascular necrosis of the femoral head

The early and accurate diagnosis of steroid-induced avascular necrosis of the femoral head (SANFH) is appealing considering its irreversible progression and serious consequence for the patients. The purpose of this study was to investigate the metabolic change of SANFH for its early detection. Two stages were designed in this study, namely discovery and verification. Except the biochemical index anomaly and the accidental death, 30 adult healthy adult Japanese white rabbits were used for screening out the potential metabolites in discovery experiment and 13 rabbits were used in verification experiment. The femoral heads were assessed with magnetic resonance imaging and transmission electron microscopy. The metabolomic profiling of serum samples were analysis by UHPLC-MS/MS. Metabolomic cluster analysis enable us to differentiate the rabbits without and with injection of the glucocorticoid in 1 week even when there is no obvious abnormal symptom in behaviors or imaging diagnosis. The majority of differential metabolites were identified as phospholipids which were observed significant change after injection of glucocorticoid in 1, 2, 3 weeks. And the results obtained in verification experiment of 6 weeks showed that these differential metabolites exhibited consistent trends in late progression with that in early-stage. At the end of 6 weeks the damage of SANFH could be verified by pathological imaging. Therefore the finding of serum metabolite profile links to the progression of SANFH and provides the potential of early detection of SANFH.