Early diagnosis and treatment of steroid-induced osteonecrosis of the femoral head

The Multiplicative Effects of Individual Risk Factors in the Development of Osteonecrosis of the Femoral Head

BACKGROUND

While individual risk factors, including chronic corticosteroid use, alcohol abuse, and smoking, are implicated in osteonecrosis of the femoral head (ONFH), the degree to which multiple risk factors increase risk is unknown. This study aimed to: (1) identify the demographic characteristics of patients who have ONFH; (2) quantify the effects of individual risk factors on ONFH development; (3) quantify the effects of combined risk factors on ONFH development; and (4) determine the prognostic implications of combined risk factors on ONFH development.

METHODS

This was a retrospective cohort study. A national insurance database was used to study a population of 2,612,383 adult patients who had a 10-year follow-up period. There were 10,233 patients identified who had a diagnosis of ONFH. We identified patients who had chronic corticosteroid use, tobacco use, and/or alcohol abuse and assessed the risk of developing ONFH over a 10-year period. Patients who had individual and multiple risk factors were grouped for comparison, and Chi-square analyses were performed.

RESULTS

Higher proportions of patients who had each individual risk factor developed ONFH compared to proportions of patients who did not have risk factors. Patients who had combined risk factors were at greater risk of developing ONFH compared to patients who had no risk factors and those who had single risk factors. Combined risk factors demonstrated multiplicative effects on the development of ONFH: tobacco-alcohol risk ratio (RR) 5.25, corticosteroid-alcohol RR 10.20, tobacco-corticosteroid RR 8.69, and corticosteroid-tobacco-alcohol RR 12.54. Patients who had combined risk factors developed ONFH at younger ages than those who had single risk factors. Kaplan-Meier curve analyses demonstrated worse 10-year hip survival in the setting of combined risk factors.

CONCLUSIONS

Combined risk factors have a multiplicative effect on the risk of developing of atraumatic ONFH. Orthopaedic surgeons may care for at-risk individuals through modulation of risk factors.

LEVEL OF EVIDENCE

Retrospective Cohort Study, Level III.

HIF-1α in cartilage homeostasis, apoptosis, and glycolysis in mice with steroid-induced osteonecrosis of the femoral head

With the prevalence of coronavirus disease 2019, the administration of glucocorticoids (GCs) has become more widespread. Treatment with high-dose GCs leads to a variety of problems, of which steroid-induced osteonecrosis of the femoral head (SONFH) is the most concerning. Since hypoxia-inducible factor 1α (HIF-1α) is a key factor in cartilage development and homeostasis, it may play an important role in the development of SONFH. In this study, SONFH models were established using methylprednisolone (MPS) in mouse and its proliferating chondrocytes to investigate the role of HIF-1α in cartilage differentiation, extracellular matrix (ECM) homeostasis, apoptosis and glycolysis in SONFH mice. The results showed that MPS successfully induced SONFH in vivo and vitro, and MPS-treated cartilage and chondrocytes demonstrated disturbed ECM homeostasis, significantly increased chondrocyte apoptosis rate and glycolysis level. However, compared with normal mice, not only the expression of genes related to collagens and glycolysis, but also chondrocyte apoptosis did not demonstrate significant differences in mice co-treated with MPS and HIF-1α inhibitor. And the effects observed in HIF-1α activator-treated chondrocytes were similar to those induced by MPS. And HIF-1α degraded collagens in cartilage by upregulating its downstream target genes matrix metalloproteinases. The results of activator/inhibitor of endoplasmic reticulum stress (ERS) pathway revealed that the high apoptosis rate induced by MPS was related to the ERS pathway, which was also affected by HIF-1α. Furthermore, HIF-1α affected glucose metabolism in cartilage by increasing the expression of glycolysis-related genes. In conclusion, HIF-1α plays a vital role in the pathogenesis of SONFH by regulating ECM homeostasis, chondrocyte apoptosis, and glycolysis.

Selenium nanoparticles/carboxymethyl chitosan/alginate antioxidant hydrogel for treating steroid-induced osteonecrosis of the femoral head

Oxidative stress plays a crucial role in steroid-induced osteonecrosis of the femoral head (SONFH). Although several antioxidant strategies have been investigated for treating SONFH, their antioxidant efficiencies and therapeutic effects remain unsatisfactory. Here, we developed a selenium nanoparticles/carboxymethyl chitosan/alginate (SeNPs/CMC/Alg) antioxidant hydrogel and evaluated its ability to treat SONFH. In vitro assays indicated that the SeNPs/CMC/Alg hydrogel exhibited excellent properties, such as low cytotoxicity, sustained SeNPs release, and favorable antioxidant activity. Under oxidative stress, the SeNPs/CMC/Alg hydrogel promoted reactive oxygen species (ROS) elimination and enhanced the osteogenic and proangiogenic abilities of bone marrow mesenchymal stem cells (BMSCs). After establishing a rabbit model of SONFH, the SeNPs/CMC/Alg hydrogel was transplanted into the femoral head after core decompression (CD) surgery. Radiographic and histological analyses revealed that the hydrogel treatment alleviated SONFH by eliminating ROS and promoting osteogenesis and angiogenesis compared to those in the CD and CMC/Alg groups. In vitro and in vivo studies indicated that the Wnt/β-catenin signaling pathway was activated by the SeNPs/CMC/Alg hydrogel in both hydrogen peroxide-conditioned BMSCs and necrotic femoral heads. These findings indicate that local transplantation of the SeNPs/CMC/Alg hydrogel is beneficial for treating SONFH, as it promotes ROS elimination and activation of the Wnt/β-catenin signaling pathway.

X-ray, digital tomographic fusion, CT, and MRI in early ischemic necrosis of the femoral head

To investigate the imaging performance of radiography, digital tomographic fusion (DTS), computed tomography (CT), and magnetic resonance imaging (MRI) in the diagnosis of early avascular necrosis of the femoral head (ANFH). A total of 220 patients with ANFH who visited our hospital from January 2020 to January 2022 were included in the study. X-ray, DTS, CT, and MRI examinations of both hips were performed for all patients. The trabecular structure, bone density changes, femoral head morphology, and joint space changes were observed using the aforementioned imaging modalities. The staging was performed according to the Association Research Circulation Osseous (ARCO) criteria. The diagnostic detection rate of each imaging modality, and the sensitivity, specificity, positive predictive value, and negative predictive value of each examination for diagnosing early ANFH were calculated and compared. Patients were diagnosed with stage I (n = 65), stage II (n = 85), stage III (n = 32), and stage IV (n = 38) ANFH. For MRI, the detection rate (97.7%), sensitivity (94.7%), specificity (88.6%), positive predictive value (95.9%), and negative predictive value (92.5%), for diagnosing early ANFH, were significantly higher than those of other imaging methods (P < .05). MRI is the most accurate and sensitive imaging method for diagnosing early ANFH and has important clinical applications.

Preclinical models for studying corticosteroid-induced osteonecrosis of the femoral head

Nontraumatic osteonecrosis of the femoral head (ONFH) is a refractory condition that commonly results in femoral head collapse and degenerative arthritis of the hip. In the early stages, surgical procedures for hip preservation, including core decompression (CD), have been developed to prevent progressive collapse of the femoral head. Optimization of bone regeneration and biological augmentation may further enhance the therapeutic efficacy of CD for ONFH. Thus, combining CD with cell-based therapy has recently been proposed. In fact, patients treated with cell-based therapy using autologous bone marrow concentrate demonstrate improved survivorship of the femoral head, compared with conventional CD alone. Preclinical research studies to investigate adjunctive therapies for CD often utilize the rabbit model of corticosteroid-induced ONFH. Mesenchymal stem cells (MSCs) are known to promote osteogenesis and angiogenesis, and decrease inflammation in bone. Local drug delivery systems have the potential to achieve targeted therapeutic effects by precisely controlling the drug release rate. Scaffolds can provide an osteoconductive structural framework to facilitate the repair of osteonecrotic bone tissue. We focused on the combination of both cell-based and scaffold-based therapies for bone tissue regeneration in ONFH. We hypothesized that combining CD and osteoconductive scaffolds would provide mechanical strength and structural cell guidance; and that combining CD and genetically modified (GM) MSCs to express relevant cytokines, chemokines, and growth factors would promote bone tissue repair. We developed GM MSCs that overexpress the anti-inflammatory, pro-reconstructive cytokines platelet-derived growth factor-BB to provide MSCs with additional benefits and investigated the efficacy of combinations of these GM MSCs and scaffolds for treatment of ONFH in skeletally mature male New Zealand white rabbits. In the future, the long-term safety, efficacy, durability, and cost-effectiveness of these and other biological and mechanical treatments must be demonstrated for the patients affected by ONFH.

No evidence of genetic causality between diabetes and osteonecrosis: a bidirectional two-sample Mendelian randomization analysis

OBJECTIVE

This study aimed to examine whether diabetes mellitus is causally associated with osteonecrosis.

METHOD

Using publicly accessible genome-wide association study statistics, a bidirectional two-sample Mendelian randomization analysis was carried out. In order to determine whether diabetes has a causal effect on osteonecrosis and whether osteonecrosis has a causal effect on diabetes, we extracted six date on diabetes in Europeans from IEU OpenGWAS and GWAS Catalogue and osteonecrosis in Europeans from FinnGen. We then evaluated the data using inverse variance weighting, MR-Egger regression, weighted median, weighted mode, and simple mode. The results' stability and dependability were then evaluated using sensitivity analysis and heterogeneity analysis. Finally, meta-analysis is used to further confirm if there is a relationship between diabetes and osteonecrosis.

RESULTS

When diabetes was used as an exposure factor, MR-Egger regression showed that directional fold product was unlikely to bias the results. Cochran's Q test showed only minor heterogeneity in a few data sets. Multidirectional tests Egger-intercept, MR-PRESSO and funnel plots for most data did not show multidirectional and asymmetry at the gene level. Most of the IVW results showed no causal relationship between diabetes mellitus and osteonecrosis. The results of meta-analysis of IVW methods further confirmed the absence of a causal relationship. Inverse MR analysis also showed no causal relationship between osteonecrosis and diabetes.

CONCLUSION

Results of bidirectional MR analysis show no evidence of causal relationship between diabetes and osteonecrosis.

Core decompression combined with local DFO administration loaded on polylactic glycolic acid scaffolds for the treatment of osteonecrosis of the femoral head: a pilot study

BACKGROUND

Deferoxamine (DFO) angiogenesis induction potential has been demonstrated in earlier studies, but not in the osteonecrosis of the femoral head (ONFH). In this study, we evaluated the outcome of ONFH treated with combined core decompression and local DFO administration loaded on Polylactic Glycolic Acid (PLGA).

PATIENTS AND METHODS

In a pilot experimental study, six patients (10 hips) with early-stage non-traumatic ONFH were treated by core decompression, and concurrent injection of local DFO loaded on PLGA scaffold into the subchondral femoral head. Outcome measures were evaluated before the surgery and 12 and 24 months after the surgery and included visual analog scale (VAS) for pain, modified Merle d'Aubigné-Postel (MAP) score for hip function by MRI, and rate of osteonecrosis assessed by the modified.

RESULTS

The mean MPA score was 14.7 ± 1.16 before the surgery and 16.7 ± 1.41 one year after the surgery (P = 0.004). The mean VAS for pain was 4.7 ± 1.25 before the surgery and 1.8 ± 1.03 one year after the surgery (P = 0.005). The mean Kerboul angle was 219 ± 58.64 before the operation and 164.6 ± 41.82 one year after the operation (P < 0.001). Osteonecrosis progression or collapse was not seen in any of the patients at the final follow-up. No postoperative side effect attributed to the DFO was noticed, as well.

CONCLUSION

In short-term follow-up, combined core decompression and local DFO administration not only prevent the progression of ONFH but also reduces the rate of osteonecrosis significantly. However, future controlled studies are required to confirm the present results.

TRIAL REGISTRATION

IRCT20161121031003N3, 16/04/2019.

FAR591 promotes the pathogenesis and progression of SONFH by regulating Fos expression to mediate the apoptosis of bone microvascular endothelial cells

The specific pathogenesis of steroid-induced osteonecrosis of the femoral head (SONFH) is still not fully understood, and there is currently no effective early cure. Understanding the role and mechanism of long noncoding RNAs (lncRNAs) in the pathogenesis of SONFH will help reveal the pathogenesis of SONFH and provide new targets for its early prevention and treatment. In this study, we first confirmed that glucocorticoid (GC)-induced apoptosis of bone microvascular endothelial cells (BMECs) is a pre-event in the pathogenesis and progression of SONFH. Then, we identified a new lncRNA in BMECs via lncRNA/mRNA microarray, termed Fos-associated lincRNA ENSRNOT00000088059.1 (FAR591). FAR591 is highly expressed during GC-induced BMEC apoptosis and femoral head necrosis. Knockout of FAR591 effectively blocked the GC-induced apoptosis of BMECs, which then alleviated the damage of GCs to the femoral head microcirculation and inhibited the pathogenesis and progression of SONFH. In contrast, overexpression of FAR591 significantly promoted the GC-induced apoptosis of BMECs, which then aggravated the damage of GCs to the femoral head microcirculation and promoted the pathogenesis and progression of SONFH. Mechanistically, GCs activate the glucocorticoid receptor, which translocates to the nucleus and directly acts on the FAR591 gene promoter to induce FAR591 gene overexpression. Subsequently, FAR591 binds to the Fos gene promoter (-245∼-51) to form a stable RNA:DNA triplet structure and then recruits TATA-box binding protein associated factor 15 and RNA polymerase II to promote Fos expression through transcriptional activation. Fos activates the mitochondrial apoptotic pathway by regulating the expression of Bcl-2 interacting mediator of cell death (Bim) and P53 upregulated modulator of apoptosis (Puma) to mediate GC-induced apoptosis of BMECs, which leads to femoral head microcirculation dysfunction and femoral head necrosis. In conclusion, these results confirm the mechanistic link between lncRNAs and the pathogenesis of SONFH, which helps reveal the pathogenesis of SONFH and provides a new target for the early prevention and treatment of SONFH.

Astragalus polysaccharide ameliorates steroid-induced osteonecrosis of the femoral head by regulating miR-200b-3p-mediated Wnt/β-catenin signaling pathway via inhibiting SP1 expression : Astragalus polysaccharide regulates SONFH via SP1

BACKGROUND

Steroid-induced osteonecrosis of the femoral head (SONFH) is the necrosis of the femur bone caused by prolonged and massive use of corticosteroids. The present study probed into the significance of Astragalus polysaccharide (APS) in SONFH progression.

METHODS

SONFH cell model was constructed using murine long bone osteocyte Y4 (MLO-Y4) cells and then treated with APS. mRNA microarray analysis selected differentially expressed genes between control group and SONFH group. RT-qPCR determined SP1 and miR-200b-3p expression. Levels of SP1, β-catenin, autophagy-related proteins (LC3II/LC3I, Beclin1, p62) and apoptosis-related proteins (Bax, C-caspase3, C-caspase9, Bcl-2) were tested by Western blot. ChIP and luciferase reporter assays confirmed relationship between SP1 and miR-200b-3p. Fluorescence intensity of LC3 in cells was detected by immunofluorescence. Flow cytometry assessed cell apoptosis. Osteonecrosis tissues from SONFH mice were examined by HE and TRAP staining.

RESULTS

APS induced autophagy and suppressed apoptosis in SONFH cell model. APS inhibited SP1 expression and SP1 overexpression reversed effects of APS on SONFH cell model. Mechanistically, SP1 targeted miR-200b-3p to inhibit Wnt/β-catenin pathway. MiR-200b-3p depletion rescued the promoting effect of SP1 on SONFH cell model by activating Wnt/β-catenin pathway. HE staining showed that APS treatment reduced the empty lacunae and alleviated inflammation in trabecular bone of SONFH mice. TRAP staining revealed decreased osteoclasts number in SONFH mice after APS treatment.

CONCLUSION

APS regulated osteocyte autophagy and apoptosis via SP1/miR-200b-3p axis and activated Wnt/β-catenin signaling, thereby alleviating SONFH, shedding new insights for therapy of SONFH.

The indications for core decompression surgery in patients with ARCO stage I-II osteonecrosis of the femoral head: a new, comprehensive prediction system

BACKGROUND

Core decompression (CD) is considered the most popular treatment method for patients with Association Research Circulation Osseous (ARCO) stage I-II osteonecrosis of the femoral head (ONFH). However, the definitive indication for CD is currently not well established.

METHODS

This was a retrospective cohort study. Patients who were diagnosed with ARCO stage I-II ONFH and who underwent CD were included. According to the prognosis, the patients were divided into two groups: collapse of the femoral head after CD and noncollapse of the femoral head. Independent risk factors for the failure of CD treatment were identified. Subsequently, a new scoring system that included all these risk factors was built to help estimate the individual risk of CD failure in patients who were planning to undergo CD.

RESULTS

The study included 1537 hips after decompression surgery. The overall failure rate of CD surgery was 52.44%. Seven independent prognostic factors for failed CD surgery were identified, such as male sex (HR = 75.449; 95% confidence interval (CI), 42.863-132.807), Aetiology (Idiopathic HR = 2.762; 95% CI, 2.016-3.788, Steroid-induced HR = 2.543; 95% CI, 1.852-3.685), if the patient had a seated occupation (HR = 3.937; 95% CI, 2.712-5.716), age (HR = 1.045; 95% CI, 1.032-1.058), haemoglobin level (HR = 0.909; 95% CI, 0.897-0.922), disease duration (HR = 1.217; 95% CI, 1.169-1.267) and the combined necrosis angle (HR = 1.025; 95% CI, 1.022-1.028). The final scoring system included these seven risk factors, and the area under the curve of this scoring system was 0.935 (95% confidential interval = 0.922-0.948).

CONCLUSION

This new scoring system might provide evidence-based medical proof for determining whether a patient with ARCO stage I - II ONFH might benefit from CD surgery. This scoring system is crucial for making clinical decisions. Consequently, this scoring system is recommended before CD surgery, which could help determine the potential prognosis of patients.

PDGF-BB prevents destructive repair and promotes reparative osteogenesis of steroid-associated osteonecrosis of the femoral head in rabbits

Destructive repair characterized by inadequate angiogenesis and osteogenesis is the main pathological progression in steroid-associated osteonecrosis of the femoral head (SONFH). Platelet-derived growth factor-BB (PDGF-BB) is an "angiogenesis and osteogenesis coupling" factor that has been used for the treatment of bone defects in clinic. This study was designed to analyze the ability of PDGF-BB for preventing destructive repair and promoting reparative osteogenesis in SONFH. Steroid-associated osteonecrosis (SAON) was induced and triggered destructive repair of the femoral head by repeated lipopolysaccharide (LPS) and methylprednisolone (MPS) injections in rabbits. At 2, 4, and 6 weeks after induction, recombinant human PDGF-BB, neutralizing PDGF-BB antibody, or saline was intramedullary injected into the proximal femora. At week 6 after SAON induction, the proximal femora were dissected for bone architecture and histological analysis. C3H10T1/2 cells and HUVECs were used for further mechanistic investigation. After PDGF-BB treatment, type H vessels and leptin receptor-positive (LepR+) mesenchymal stem cells (MSCs) increased in the affected femoral head, and more osteoblastic osteogenesis along the bone surfaces but scattered adipocytes in bone marrow tissue than that in the SAON group. PDGF-BB treatment prevented destructive repair progression and led to 50-70 % of osteonecrotic femoral heads undergoing reparative osteogenesis. In particular, we found that PDGF-BB could mediate MSC self-renewal and maintain their osteogenic potency by activating PDGFR/Akt/GSK3β/CERB signaling in the presence of steroids. Moreover, PDGF-BB also stabled the newly formed vascular tubes by recruiting MSCs for improving intraosseous vascular integration. PDGF-BB may be a candidate for the promotion of reparative osteogenesis in SONFH.

IRF8 and its related molecules as potential diagnostic biomarkers or therapeutic candidates and immune cell infiltration characteristics in steroid-induced osteonecrosis of the femoral head

PURPOSE

Steroid-induced osteonecrosis of the femoral head (SONFH) was a refractory orthopedic hip joint disease in the young and middle-aged people, but the pathogenesis of SONFH remained unclear. We aimed to identify the potential genes and screen potential therapeutic compounds for SONFH.

METHODS

The microarray was obtained for blood tissue from the GEO database, and then it identifies differentially expressed genes (DEGs). The DEGs were analyzed to obtain the differences in immune cell infiltration. The gene functional enrichment analysis of SONFH was analyzed. The PPI of DEGs was identified through the STRING database, and the cluster modules and hub genes were ascertained using MCODE and CytoHubba, and the ROC curve of hub genes was analyzed, and the tissues distribution of hub genes was understood by the HPA, Bgee and BioGPS databases. The hub genes and target miRNAs and corresponding upstream lncRNAs were predicted by TargetScan, miRDB and ENCORI database. Subsequently, we used CMap, DGIdb and L1000FWD databases to identify several potential therapeutic molecular compounds for SONFH. Finally, the AutoDockTools Vina, PyMOL and Discovery Studio were employed for molecular docking analyses between compounds and hub genes.

RESULTS

The microarray dataset GSE123568 was obtained related to SONFH. There were 372 DEGs including 197 upregulated genes and 175 downregulated genes by adjusted P value < 0.01 and |log₂FC|> 1. Several significant GSEA enrichment analysis and biological processes and KEGG pathway associated with SONFH were identified, which were significantly related to cytoskeleton organization, nucleobase-containing compound catabolic process, NOD-like receptor signaling pathway, MAPK signaling pathway, FoxO signaling pathway, neutrophil-mediated immunity, neutrophil degranulation and neutrophil activation involved in immune response. Activated T cells CD4 memory, B cells naïve, B cells memory, T cells CD8 and T cells gamma delta might be involved in the occurrence and development of SONFH. Three cluster modules were identified in the PPI network, and eleven hub genes including FPR2, LILRB2, MNDA, CCR1, IRF8, TYROBP, TLR1, HCK, TLR8, TLR2 and CCR2 were identified by Cytohubba, which were differed in bone marrow, adipose tissue and blood, and which had good diagnostic performance in SONFH. We identified IRF8 and 10 target miRNAs that was utilized including Targetsan, miRDB and ENCORI databases and 8 corresponding upstream lncRNAs that was revealed by ENCORI database. IRF8 was detected with consistent expression by qRT-PCR. Based on the CMap, DGIdb and L1000FWD databases, the 11 small molecular compounds that were most strongly therapeutic correlated with SONFH were estradiol, genistein, domperidone, lovastatin, myricetin, fenbufen, rosiglitazone, sirolimus, phenformin, vorinostat and vinblastine. All of 11 small molecules had good binding affinity with the IRF8 in molecular docking.

CONCLUSION

The occurrence of SONFH was associated with a "multi-target" and "multi-pathway" pattern, especially related to immunity, and IRF8 and its noncoding RNA were closely related to the development of SONFH. The CMap, DGIdb and L1000FWD databases could be effectively used in a systematic manner to predict potential drugs for the prevention and treatment of SONFH. However, additional clinical and experimental research is warranted.

Effects of Simvastatin on Cartilage Homeostasis in Steroid-Induced Osteonecrosis of Femoral Head by Inhibiting Glucocorticoid Receptor

Steroid-induced osteonecrosis of femoral head (SONFH) is one of the most common bone disorders in humans. Statin treatment is beneficial in preventing the development of SONFH through anti-inflammation effects and inhibition of the glucocorticoid receptor (GR). However, potential mechanisms of statin action remain to be determined. In this study, pulse methylprednisolone (MP) treatment was used to induce SONFH in broilers, and then MP-treated birds were administrated with simvastatin simultaneously to investigate the changes in cartilage homeostasis. Meanwhile, chondrocytes were isolated, cultured, and treated with MP, simvastatin, or GR inhibitor in vitro. The changes in serum homeostasis factors, cell viability, and expression of GR were analyzed. The results showed that the morbidity of SONFH in the MP-treated group increased significantly compared with the simvastatin-treated and control group. Furthermore, MP treatment induced apoptosis and high-level catabolism and low-level anabolism in vitro and vivo, while simvastatin significantly decreased catabolism and slightly recovered anabolism via inhibiting GR and the hypoxia-inducible factor (HIF) pathway. The GR inhibitor or its siRNA mainly affected the catabolism of cartilage homeostasis in vitro. In conclusion, the occurrence of SONFH in broilers was related to the activation of GR and HIF pathway, and imbalance of cartilage homeostasis. Simvastatin and GR inhibitor maintained cartilage homeostasis via GR and the HIF pathway.

Molecular Imaging of Steroid-Induced Osteonecrosis of the Femoral Head through iRGD-Targeted Microbubbles

Osteonecrosis of the femoral head (ONFH) is a disease that is commonly seen in the clinic, but its detection rate remains limited, especially at the early stage. We developed an ultrasound molecular imaging (UMI) approach for early diagnosis of ONFH by detecting the expression of integrin αvβ3 during the pathological changes in steroid-induced osteonecrosis of the femoral head (SIONFH) in rat models. The integrin αvβ3-targeted PLGA or lipid microbubbles modified with iRGD peptides were fabricated and characterized. Their adhesion efficiency to mouse brain microvascular endothelial cells in vitro was examined, and the better LIPOiRGD was used for further in vivo molecular imaging of SIONFH rats at 1, 3 and 5 weeks; revealing significantly higher UMI signals could be observed in the 3-week and 5-week SIONFH rats but not in the 1-week SIONFH rats in comparison with the non-targeted microbubbles (32.75 ± 0.95 vs. 0.17 ± 0.09 for 5 weeks, p < 0.05; 5.60 ± 1.31 dB vs. 0.94 ± 0.81 dB for 3 weeks, p < 0.01; 1.13 ± 0.13 dB vs. 0.73 ± 0.31 dB for 1 week, p > 0.05). These results were consistent with magnetic resonance imaging data and confirmed by immunofluorescence staining experiments. In conclusion, our study provides an alternative UMI approach to the early evaluation of ONFH.

Steroid-induced osteonecrosis

Osteonecrosis associated with the use of glucocorticoids is a severe, potentially debilitating complication. In broader terms, it commonly involves the femoral head with secondary hip osteoarthritis. Osteonecrosis can also be caused by trauma and other non-traumatic factors besides steroid treatment. Nonetheless, glucocorticoid use is frequently observed in clinical settings in which this represents a common therapeutic option, including general practice, rheumatology and clinical immunology, among others. The pathogenesis involves genetic components, vascular impairment, adipocyte hypertrophy, and increased intraosseous pressure, ultimately leading to marrow and bone ischemia and necrosis and the process rapidly becomes irreversible. Osteonecrosis manifests with pain and impaired motility while the diagnosis is usually made with magnetic resonance imaging allowing early detection and potentially (dependent on the patient's needs for steroids and stage) timely management with conservative options, followed by joint replacement at late stages. In this review we discuss the pathogenesis, risk factors, diagnosis, staging, and management of this complication associated with glucocorticoid treatment.

Biomechanical analysis of the drilling parameters for early osteonecrosis of the femoral head

BACKGROUND AND OBJECTIVE

Core decompression is a surgical procedure commonly used to treat the early osteonecrosis of the femoral head. However, It is not known whether different drilling parameters affect postoperative biomechanical strength. This study aimed to analyze the mechanical stability of different drilling locations and diameters of core decompression using finite element analysis.

METHODS

Finite element models were established based on computed tomography images obtained from five healthy participants, including the different drilling locations (Lesser trochanter: Above, Parallel, and Below) and diameters. Biomechanical parameters including stiffness and stress were evaluated under slow running loads.

RESULTS

At the same drilling diameter, the femoral stiffness was highest (p < 0.05) in the Above group and lowest in the Below group, while the maximum equivalent stress of the entry area and the necrotic area was highest (p < 0.05) in the Below group and lowest in the Above group. With the increase of drilling diameters, the stiffness decreased and its decreased percentage comparing the preoperative: Above (1.06-8.82%), Parallel (2.51-13.61%), and Below (3.99-15.06%). The maximum equivalent stress of the entry area and necrotic area increased as the drilling diameter increased, and its increased percentage comparing the preoperative, for the entry area: Above (14.11-219.58%), Parallel (35.91-306.37%), and Below (46.12-240.98%); for the necrotic area: Above (13.64-114.69%), Parallel (29.37-187.76%), and Below (44.76-202.10%). The range of safety drilling parameters (SDP) was obtained (Below<9 mm, Parallel<11 mm, and Above<13 mm) by comparing the maximum equivalent stress of two areas and its yield strength. For patients of different sizes and normal bone mineral density (BMD), the maximum equivalent stress of the two areas did not exceed its yield strength using the range of SDP, except for the patients with abnormal BMD (Osteoporosis) or high body mass index (BMI≥28 kg/m²).

CONCLUSIONS

The biomechanical properties of early osteonecrosis of the femoral head deceased with increasing drilling diameters parameters, especially at the location below the lesser trochanter. The SDP (Below<9 mm, Parallel<11 mm, and Above<13 mm) is a suitable reference for most patients to perform slow running postoperatively, while it may be not suitable for patients with osteoporosis or obesity.

Impact of Femoral Neck Cortical Bone Defect Induced by Core Decompression on Postoperative Stability: A Finite Element Analysis

Objective

To analyze the impact of femoral neck cortical bone defect induced by core decompression on postoperative biomechanical stability using the finite element method.

Methods

Five finite element models (FEMs) were established, including the standard operating model and four models of cortical bone defects at different portions of the femoral neck (anterior, posterior, superior, and inferior). The maximum stress of the proximal femur was evaluated during normal walking and walking downstairs.

Results

Under both weight-bearing conditions, the maximum stress values of the five models were as follows: femoral neck (inferior) > femoral neck (superior) > femoral neck (posterior) > femoral neck (anterior) > standard operation. Stress concentration occurred in the areas of femoral neck cortical bone defect. Under normal walking, the maximum stress of four bone defect models and its increased percentage comparing the standard operation were as follows: anterior (17.17%), posterior (39.02%), superior (57.48%), and inferior (76.42%). The maximum stress was less than the cortical bone yield strength under normal walking conditions. Under walking downstairs, the maximum stress of four bone defect models and its increased percentage comparing the standard operation under normal walking were as follows: anterior (36.75%), posterior (67.82%), superior (83.31%), and inferior (103.65%). Under walking downstairs conditions, the maximum stress of bone defect models (anterior, posterior, and superior) was less than the yield strength of cortical bone, while the maximum stress of bone defect model (inferior) excessed yield strength value.

Conclusions

The femoral neck cortical bone defect induced by core decompression can carry out normal walking after surgery. To avoid an increased risk of fracture after surgery, walking downstairs should be avoided when the cortical bone defect is inferior to the femoral neck except for the other three positions (anterior, posterior, and superior).

Animal Models of Femur Head Necrosis for Tissue Engineering and Biomaterials Research

Femur head necrosis, also known as osteonecrosis of the femoral head (ONFH), is a widespread disabling pathology mostly affecting young and middle-aged population and one of the major causes of total hip arthroplasty in the elderly. Currently, there are limited number of different clinical or medication options for the treatment or the reversal of progressive ONFH, but their clinical outcomes are neither satisfactory nor consistent. In pursuit of more reliable therapeutic strategies for ONFH, including recently emerged tissue engineering and biomaterials approaches, in vivo animal models are extremely important for therapeutic efficacy evaluation and mechanistic exploration. Based on the better understanding of pathogenesis of ONFH, animal modeling method has evolved into three major routes, including steroid-, alcohol-, and injury/trauma-induced osteonecrosis, respectively. There is no consensus yet on a standardized ONFH animal model for tissue engineering and biomaterial research; therefore, appropriate animal modeling method should be carefully selected depending on research purposes and scientific hypotheses. In this work, mainstream types of ONFH animal model and their modeling techniques are summarized, showing both merits and demerits for each. In addition, current studies and experimental techniques of evaluating therapeutic efficacy on the treatment of ONFH using animal models are also summarized, along with discussions on future directions related to tissue engineering and biomaterial research. Impact statement Exploration of tissue engineering and biomaterial-based therapeutic strategy for the treatment of femur head necrosis is important since there are limited options available with satisfactory clinical outcomes. To promote the translation of these technologies from benchwork to bedside, animal model should be carefully selected to provide reliable results and clinical outcome prediction. Therefore, osteonecrosis of the femoral head animal modeling methods as well as associated tissue engineering and biomaterial research are overviewed and discussed in this work, as an attempt to provide guidance for model selection and optimization in tissue engineering and biomaterial translational studies.

The Role of Structural Deterioration and Biomechanical Changes of the Necrotic Lesion in Collapse Mechanism of Osteonecrosis of the Femoral Head

Osteonecrosis of the femoral head (ONFH) is a crippling disease which is due to a lack of effective therapeutic measures. Its natural progression is rapid, the internal bone structure of the femoral head changes dramatically, and the subsequent fractures and collapse cause severe hip pain and loss of hip function. Femoral head collapse is a critical turning point in the development of ONFH and is related to the prognosis of patients. Early prevention and intervention help to preserve the hip joint and delay femoral head collapse. However, the mechanism of collapse still needs to be further studied because it is affected by different complex factors. This review discusses the underlying causes of femoral head collapse from two aspects: structural degradation and regional changes of biomechanical properties in the necrotic femoral head.

Relationship Between Blood Flow and Collapse of Nontraumatic Osteonecrosis of the Femoral Head

BACKGROUND

To investigate the collapse mechanism in osteonecrosis of the femoral head (ONFH), we studied the relationship between the femoral head (FH) blood circulation changes and the collapse area histomorphometry characteristics.

METHODS

A technique involving microvascular perfusion of the FH in vitro to reconstruct the vessels in the FH at different stages of nontraumatic ONFH (40 cases). In addition, we also examined the histomorphometry characteristics in the collapse area during ONFH at different stages using the hard tissue section technique. To investigate the blood supply changes in the FH on pathological involved in the FH collapse process.

RESULTS

The results showed that in all FHs, the collapse area always involved the margin of the necrotic lesion of the lateral column. Histologically, the fracture occurred between the thickened and necrotic trabeculae at the junction. We found that the collapse started at the lateral column of the FH in the necrotic lesion and that the lateral column was ischemic, which caused the FH to begin to collapse.

CONCLUSIONS

Based on the above findings, the relationship between associations of the blood circulation to the collapse showed that if a portion of the blood supply of the lateral column (the superior retinacular artery) was preserved, the prognosis of the natural progression of the diseases was improved, the collapse rate was low and collapse occurred later. The blood circulation of artery in the lateral column was good, and the FH maintained an intact shape even if the internal region was ischemic. Therefore, we can predict the collapse of the FH by measuring the blood flow in the lateral area of the FH, thus providing guidance for the selection of FH-preserving clinical therapy in young and middle-aged patients.

CLINICAL RELEVANCE

This work provides a proof of how to predict the collapse of the FH by measuring the blood flow, providing guidance for FH-preserving clinical therapy in young and middle-aged patients.

Osteogenesis-Related Long Noncoding RNA GAS5 as a Novel Biomarker for Osteonecrosis of Femoral Head

Background: The lack of effective biomarkers makes it difficult to achieve early diagnosis and intervention for osteonecrosis of the femoral head (ONFH). Hence, we aimed to identify novel long noncoding RNA (lncRNA) biomarkers for ONFH.

Methods: High-throughput RNA sequencing was performed to detect lncRNA and mRNA expression levels in subchondral bone samples from three patients with ONFH and three patients with femoral neck fractures. Integrated bioinformatics analyses were conducted to identify lncRNAs associated with ONFH development and their potential functions and signaling pathways. A co-expression network was constructed based on the gene time-series expression data in GSE113253. After selecting lncRNA GAS5 as a novel biomarker for ONFH, bone marrow mesenchymal stem cell (BMSC) osteogenic differentiation assays were performed to verify the association between lncRNA GAS5 and osteogenic differentiation. Alkaline phosphatase (ALP) staining and quantitative reverse transcription polymerase chain reaction (RT-qPCR) were used to measure the osteogenic phenotype and lncRNA GAS5 expression. Finally, for further validation, ONFH rat models were established, and lncRNA GAS5 expression in subchondral bone was detected by RT-qPCR.

Results: We identified 126 and 959 differentially expressed lncRNAs and genes, respectively. lncRNA GAS5 expression level was significantly downregulated in patients with ONFH compared to the control group patients. The BMSC osteogenic differentiation assays showed that ALP activity increased gradually from days 3 to 7, while the lncRNA GAS5 expression level was significantly upregulated in the osteogenic differentiation induction groups. Furthermore, in vivo experiments suggested that the bone volume/tissue volume value and trabecular thickness significantly decreased in the ONFH rat model group compared to the control group, whereas the trabecular space significantly increased in the ONFH group compared to the control group. In addition, the lncRNA GAS5 expression level significantly decreased in the ONFH rat model group.

Conclusion: The lncRNA GAS5 expression level was highly associated with BMSC osteogenic differentiation and was significantly downregulated in both the subchondral trabecular bone tissue of ONFH patients and ONFH rat models. Therefore, lncRNA GAS5 can serve as an ONFH osteogenic biomarker to provide an effective target for early diagnosis and molecular therapy of ONFH.

Screening of Potential Biomarkers in the Peripheral Serum for Steroid-Induced Osteonecrosis of the Femoral Head Based on WGCNA and Machine Learning Algorithms

Background. Steroid-induced osteonecrosis of the femoral head (SONFH) has produced a substantial burden of medical and social experience. However, the current diagnosis is still limited. Thus, this study is aimed at identifying potential biomarkers in the peripheral serum of patients with SONFH. Methods. The expression profile data of SONFH (number: GSE123568) was acquired from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) in SONFH were identified and used for weighted gene coexpression network analysis (WGCNA). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to investigate the biological functions. The protein-protein interaction (PPI) network and machine learning algorithms were employed to screen for potential biomarkers. Gene set enrichment analysis (GSEA), transcription factor (TF) enrichment analysis, and competing endogenous RNA (ceRNA) network were used to determine the biological functions and regulatory mechanisms of the potential biomarkers. Results. A total of 562 DEGs, including 318 upregulated and 244 downregulated genes, were identified between SONFH and control samples, and 94 target genes were screened based on WGCNA. Moreover, biological function analysis suggested that target genes were mainly involved in erythrocyte differentiation, homeostasis and development, and myeloid cell homeostasis and development. Furthermore, GYPA, TMCC2, and BPGM were identified as potential biomarkers in the peripheral serum of patients with SONFH based on machine learning algorithms and showed good diagnostic values. GSEA revealed that GYPA, TMCC2, and BPGM were mainly involved in immune-related biological processes (BPs) and signaling pathways. Finally, we found that GYPA might be regulated by hsa-miR-3137 and that BPGM might be regulated by hsa-miR-340-3p. Conclusion. GYPA, TMCC2, and BPGM are potential biomarkers in the peripheral serum of patients with SONFH and might affect SONFH by regulating erythrocytes and immunity.

Double Trouble-COVID-19 and the Widespread Use of Corticosteroids: Are We Staring at an Osteonecrosis Epidemic?

Background

A combination of immune-mediated vascular damage and routine use of systemic corticosteroid (CS) therapy in COVID-19 may significantly increase the risk and burden of osteonecrosis (ON) after COVID-19. This narrative review explores the pathogenesis, risk factors, and possible preventive and early treatment measures for ON in COVID-19.

Methods

For this narrative review, an extensive literature search was performed using the PubMed, Medline, and Science Direct databases from January 2000 to August 2021 for relevant articles on etiopathogenesis, epidemiology, clinical manifestations, and treatment of severe acute respiratory syndrome coronavirus (SARS-CoV) infection and steroid-induced ON (SION).

Results

Pathogenesis of COVID-19, utility of corticosteroids in the treatment of COVID-19, pathogenesis of SION vis-a-vis SARS-CoV infection, associated risk factors, and early diagnosis and treatment of ON following CS therapy of SARS-CoV infection were discussed.

Conclusion

Preliminary data of COVID-19 and similar trends from the SARS 2003 epidemic indicate that the "angiocentric" pathogenesis of SARS-CoV-2 and treatment with high-dose CS may increase the risk of ON in COVID-19 patients. Risk stratification based on CS intake during COVID-19 treatment can help identify subjects at moderate to high-risk for ON where early preventive and follow-up plans can be initiated.

Whole-body magnetic resonance imaging (WBMRI) versus whole-body computed tomography (WBCT) for myeloma imaging and staging

Myeloma-associated bone disease (MBD) develops in about 80-90% of patients and severely affects their quality of life, as it accounts for the majority of mortality and morbidity. Imaging in multiple myeloma (MM) and MBD is of utmost importance in order to detect bone and bone marrow lesions as well as extraosseous soft-tissue masses and complications before the initiation of treatment. It is required for determination of the stage of disease and aids in the assessment of treatment response. Whole-body low-dose computed tomography (WBLDCT) is the key modality to establish the initial diagnosis of MM and is now recommended as reference standard procedure for the detection of lytic destruction in MBD. In contrast, whole-body magnetic resonance imaging (WBMRI) has higher sensitivity for the detection of focal and diffuse plasma cell infiltration patterns of the bone marrow and identifies them prior to osteolytic destruction. It is recommended for the evaluation of spinal and vertebral lesions, while functional, diffusion-weighted MRI (DWI-MRI) is a promising tool for the assessment of treatment response. This review addresses the current improvements and limitations of WBCT and WBMRI for diagnosis and staging in MM, underlining the fact that both modalities offer complementary information. It further summarizes the corresponding radiological findings and novel technological aspects of both modalities.

Neohesperidin promotes the osteogenic differentiation of human bone marrow stromal cells by inhibiting the histone modifications of lncRNA SNHG1

Neohesperidin (NH) was reported to regulate osteoclastic differentiation, while LncRNA SNHG1 could inhibit osteogenic differentiation of bone marrow stromal cells (BMSCs). In this study, we aimed to explore whether SNHG1-mediated osteogenic differentiation could be regulated by NH. Osteonecrosis and adjacent tissues, as well as normal bone marrow samples were gathered. BMSCs were isolated from normal bone marrow samples by Ficoll density gradient and identified by flow cytometry. Histopathological changes of tissues were detected by hematoxylin-eosin staining. After the treatment with NH or transfection, cell viability, osteogenic differentiation, and the activity of alkaline phosphatase (ALP) in BMSCs were detected by MTT, alizarin red staining, and microplate method, respectively. The histone modification and expressions of SNHG1 and osteogenic marker genes in tissues or BMSCs were detected by q-PCR and Chromatin Immunoprecipitation (ChIp). SNHG1 was highly expressed in osteonecrosis tissues, and typical signs of empty lacunae appeared in the necrotic tissues zone. NH increased viability and osteogenic differentiation of BMSCs, activity of ALP, and expressions of RUNX2, OCN and ALP. NH decreased both SNHG1 expression and H3K4me3 (activating histone modification) occupancies and increased H3K27me3 (inhibiting histone modification) occupancies of SNHG1. Furthermore, siSNHG1 enhanced osteogenic differentiation of BMSCs and expressions of RUNX2, OCN and ALP, while SNHG1 overexpression did the opposite and reversed the effects of NH on the osteogenic differentiation of BMSCs. In a word, NH promotes the osteogenic differentiation of human BMSCs by inhibiting the histone modifications of lncRNA SNHG1.

ARG2, MAP4K5 and TSTA3 as Diagnostic Markers of Steroid-Induced Osteonecrosis of the Femoral Head and Their Correlation With Immune Infiltration

Background

The diagnosis for steroid-induced osteonecrosis of the femoral head (SONFH) is hard to achieve at the early stage, which results in patients receiving ineffective treatment options and a poor prognosis for most cases. The present study aimed to find potential diagnostic markers of SONFH and analyze the effect exerted by infiltration of immune cells in this pathology.

Materials and Methods

R software was adopted for identifying differentially expressed genes (DEGs) and conducting functional investigation based on the microarray dataset. Then we combined SVM-RFE, WGCNA, LASSO logistic regression, and random forest (RF) algorithms for screening the diagnostic markers of SONFH and further verification by qRT-PCR. The diagnostic values were assessed through receiver operating characteristic (ROC) curves. CIBERSORT was then adopted for assessing the infiltration of immune cells and the relationship of infiltration-related immune cells and diagnostic markers.

Results

We identified 383 DEGs overall. This study found ARG2, MAP4K5, and TSTA3 (AUC = 0.980) to be diagnostic markers of SONFH. The results of qRT-PCR showed a statistically significant difference in all markers. Analysis of infiltration of immune cells indicated that neutrophils, activated dendritic cells and memory B cells were likely to show the relationship with SONFH occurrence and progress. Additionally, all diagnostic markers had different degrees of correlation with T cell follicular helper, neutrophils, memory B cells, and activated dendritic cells.

Conclusion

ARG2, MAP4K5, and TSTA3 are potential diagnostic genes for SONFH, and infiltration of immune cells may critically impact SONFH occurrence and progression.

The role of biomechanical forces and MALAT1/miR-329-5p/PRIP signalling on glucocorticoid-induced osteonecrosis of the femoral head

Glucocorticoid‐induced osteonecrosis of the femoral head (GIONFH) is a common orthopaedic disease. GIONFH primarily manifests clinically as hip pain in the early stages, followed by the collapse of the femoral head, narrowing of the hip joint space and damage to the acetabulum, resulting in severely impaired mobility. However, the pathogenesis of GIONFH is not clearly understood. Recently, biomechanical forces and non‐coding RNAs have been suggested to play important roles in the pathogenesis of GIONFH. This study aimed to evaluate the role of biomechanical forced and non‐coding RNAs in GIONFH. We utilized an in vivo, rat model of GIONFH and used MRI, μCT, GIONFH‐TST (tail suspension test), GIONFH‐treadmill, haematoxylin and eosin staining, qRT‐PCR and Western blot analysis to analyse the roles of biomechanical forces and non‐coding RNAs in GIONFH. We used RAW264.7 cells and MC3T3E1 cells to verify the role of MALAT1/miR‐329‐5p/PRIP signalling using a dual luciferase reporter assay, qRT‐PCR and Western blot analysis. The results demonstrated that MALAT1 and PRIP were up‐regulated in the femoral head tissues of GIONFH rats, RAW264.7 cells, and MC3T3E1 cells exposed to dexamethasone (Dex). Knockdown of MALAT1 decreased PRIP expression in rats and cultured cells and rescued glucocorticoid‐induced osteonecrosis of femoral head in rats. The dual luciferase reporter gene assay revealed a targeting relationship for MALAT1/miR‐329‐5p and miR‐329‐5p/PRIP in MC3T3E1 and RAW264.7 cells. In conclusion, MALAT1 played a vital role in the pathogenesis of GIONFH by binding to (‘sponging’) miR‐329‐5p to up‐regulate PRIP. Also, biomechanical forces aggravated the pathogenesis of GIONFH through MALAT1/miR‐329‐5p/PRIP signalling.

Correlation between continuation of glucocorticoid treatment and risk of femoral head collapse : A retrospective cohort study of patients with glucocorticoid-induced osteonecrosis of femoral head after hip-preserving interventions

OBJECTIVE

To evaluate the correlation between continuation of glucocorticoid (GC) treatment and risk of femoral head collapse in patients with glucocorticoid-induced osteonecrosis of the femoral head (GIONFH) after hip-preserving interventions.

METHODS

The cohort included patients with GIONFH who had received a hip-preserving intervention between 1 January 2014 and 1 April 2016. All hips were at the non-collapse stage. The independent variable and the dependent variable were postoperative GC use and femoral head collapse (≥3 mm), respectively. Multivariate Cox proportional hazards regression were performed to estimate the association of the variables after adjusting for other covariates.

RESULTS

A total of 27 hips (24 patients) were included for the final data analysis of which 6 hips out of 18 developed femoral head collapse (≥3 mm) in patients who discontinued taking GC postoperatively and 6 hips out of 9 developed collapse (≥3 mm) in those requiring GC treatment postoperatively. In the fully adjusted Cox proportional hazards model, the risk of femoral head collapse (≥3 mm) was higher in participants requiring postoperative GC use than those not requiring GC (hazard ratio, HR 3.7, 95% confidence interval, CI 1.1-13.0).

CONCLUSION

The results of this study demonstrated that patients with GIONFH who continued GC treatment postoperatively had a significantly increased risk of femoral head collapse (≥3 mm) compared to those who discontinued use of GC.

Neohesperidin Ameliorates Steroid-Induced Osteonecrosis of the Femoral Head by Inhibiting the Histone Modification of lncRNA HOTAIR

Background

Neohesperidin (NH) and lncRNA HOTAIR (HOTAIR) could regulate osteoclastic and osteogenic differentiation. This study aimed to explore whether HOTAIR-mediated osteogenic differentiation was regulated by NH.

Methods

Steroid-induced osteonecrosis of the femoral head (SONFH) mice model was established. Histopathological changes in mouse osteonecrosis tissues were detected by hematoxylin-eosin staining. Bone marrow stromal cells (BMSCs) were isolated from healthy mice bone marrow samples by Ficoll density gradient and identified by flow cytometry. After treating the BMSCs with NH and dexamethasone or transfecting with HOTAIR overexpression plasmids and siHOTAIR, histone modification of HOTAIR, the cell viability, osteogenic differentiation, and adipogenic differentiation were detected by chromatin immunoprecipitation, MTT, Alizarin Red and Oil Red O staining, respectively. The expressions of HOTAIR and differentiation-related factors in the BMSCs were detected by RT-qPCR and Western blot.

Results

HOTAIR was highly expressed in SONFH model mice. NH ameliorated histopathological changes in the model mice, but the effect was reversed by overexpressed HOTAIR. NH increased viability of BMSCs and the H3K27me3 occupancy of HOTAIR, but decreased the expression and the H3K4me3 occupancy of HOTAIR. HOTAIR expression was down-regulated in BMSCs after osteogenic differentiation but was up-regulated after adipogenic differentiation. HOTAIR overexpression inhibited osteogenic differentiation and the expressions of RUNX2, OCN, and ALP, but increased adipogenic differentiation and the expressions of LPL and PPARr in BMSCs; moreover, the opposite results were observed in siHOTAIR.

Conclusion

NH ameliorated SONFH by inhibiting the histone modifications of HOTAIR.

Osteogenic Effect of tsRNA-10277-Loaded Exosome Derived from Bone Mesenchymal Stem Cells on Steroid-Induced Osteonecrosis of the Femoral Head

Purpose

Steroids are known to inhibit osteogenic differentiation and subsequent bone formation in bone mesenchymal stem cells (BMSCs). However, little is known about the role of BMSC exosomes (Exos) and tRNA-derived small RNAs (tsRNAs) in steroid-induced osteonecrosis of the femoral head (SONFH). The objective of this study was to characterize the tsRNA expression profiles of plasma Exos collected from SONFH patients and healthy individuals using small RNA sequencing and further explore the effect of BMSC Exos carrying specific tsRNAs on osteogenic differentiation.

Materials and Methods

Based on insights from small RNA sequencing, five differentially expressed (DE) tsRNAs were selected for quantitative real-time polymerase chain reaction (qRT-PCR). The regulatory networks associated with interactions of the tsRNAs-mRNA-pathways were reconstructed. The osteogenesis and adipogenesis in BMSCs were detected via ALP and oil red O staining methods, respectively.

Results

A total of 345 DE small RNAs were screened, including 223 DE tsRNAs. The DE tsRNAs were enriched in Wnt signaling pathway and osteogenic differentiation. We identified five DE tsRNAs, among which tsRNA-10277 was significantly downregulated in plasma Exos of SONFH patients compared to that in healthy individuals. Dexamethasone-induced BMSCs were associated with an increased fraction of lipid droplets and decreased osteogenic differentiation, whereas BMSC Exos restored the osteogenic differentiation of that. After treatment of tsRNA-10277-loaded BMSC Exos, the lipid droplets and osteogenic differentiation ability were found to be decreased and enhanced in dexamethasone-induced BMSCs, respectively.

Conclusion

An altered tsRNA profile might be involved in the pathophysiology of SONFH. tsRNA-10277-loaded BMSC Exos enhanced osteogenic differentiation ability of dexamethasone-induced BMSCs. Our results provide novel insights into the osteogenic effect of BMSC Exos carrying specific tsRNAs on SONFH.

Combined Pharmacotherapy with Alendronate and Desferoxamine Regulate the Bone Resorption and Bone Regeneration for Preventing Glucocorticoids-Induced Osteonecrosis of the Femoral Head

Background

Osteonecrosis of the femoral head (ONFH) is a challenge for surgeons and is still without effective treatment method. This study is aimed at evaluating the combined pharmacotherapy with alendronate and desferoxamine for preventing glucocorticoid-induced osteonecrosis of the femoral head (GIOFH) and evaluating the efficacy of the combined medicine in regulating the bone resorption and bone regeneration.

Materials and Methods

Thirty-six rats were randomly assigned to three groups: group A received alendronate and desferoxamine (n = 12), group B received alendronate only (n = 12), and group C acted as the control group received placebo (n = 12). All rats induced the GIOFH using methylprednisolone combined with lipopolysaccharide. Eight weeks later, all rats were killed and their tissues were subjected to radiographic and histological analyses.

Results

According to the results, alendronate administration improved the trabecular thickness and separation in micro-CT analysis but had no significant evidence in increasing the bone area and decreasing the ratio of osteocyte lacunae in histological analysis when compared with the control group. Meanwhile, the alendronate group had more OCs, but less OCN and VEGF levels along with decreased p-AKT, HIF-1α, RANKL, and NFATc1 expressions than the control group. For comparison, alendronate combined with DFO further improved the bone volume, trabecular number, trabecular separation, and trabecular thickness with lower ratio of osteocyte lacunae and OC number, higher expression of OCN and VEGF and upregulated signal factors of HIF-1α and β-catenin, and decreased RANKL and NFATc1.

Conclusion

Combined pharmacotherapy with alendronate and desferoxamine provide significant effects in regulating the bone resorption and bone regeneration for preventing GIOFN.

Digital Subtraction Angiography and Magnetic Resonance Imaging-Based Staging of Circulatory Obstruction in the Femoral Head During Osteonecrosis of the Femoral Head Development

INTRODUCTION

Nontraumatic osteonecrosis of the femoral head (NONFH) is a common and difficult disease in orthopedics. Magnetic resonance imaging (MRI) assessment of NONFH and bone marrow edema was combined with digital subtraction angiography (DSA) to evaluate the circulatory status of NONFH in different Association Research Circulation Osseous stages. Based on the circulatory obstruction status (venous stasis, arterial ischemia, and arterial occlusion), appropriate perioperative management was adopted to achieve hip joint preservation and effectively delay the time for total hip arthroplasty in young patients.

METHODS

From January 2013 to March 2019, 41 orthopedic patients were evaluated for medical imaging. Sixty-one ONFH cases were enrolled. The inclusion criteria include: (1) Clear diagnosis of osteonecrosis of the femoral head. (2) No history of infection in the affected hip, no history of hip surgery, and no congenital hip diseases. The patients enrolled in this study were 8 women and 33 men between the ages of 19 and 64 years (mean, 39.25 ± 8.90 years). Preoperative X-ray, computed tomography, MRI, DSA, and histological data were taken.

RESULTS

The combination of DSA and MRI can efficiently show blood supply changes in the femoral head of NONFH patients at different Association Research Circulation Osseous stages; and also can possibly reveal the causes and development of NONFH. Different stages of circulatory obstruction of the femoral head can be clearly distinguished and used to determine the required perioperative management, thus yielding successful surgical outcomes.

CONCLUSIONS

The existing classification systems do not fully reflect the progression of circulatory obstruction in ONFH. Each stage of NONFH development has its own characteristics circulatory obstruction. Early-stage NONFH displays characteristic venous stasis of the femoral head, whereas advanced stage NONFH is characterized by insufficient arterial blood supply to the femoral head. Corresponding NONFH treatment strategies should be considered based on their specific circulatory status. This work also provides guidance and recommendations for adopting corresponding femoral head preserving strategies for young patients in different NONFH circulatory status.

Expression Profile Analysis of Differentially Expressed Circular RNAs in Steroid-Induced Osteonecrosis of the Femoral Head

Background

A growing number of studies have suggested that circular RNAs (circRNAs) serve as potential diagnostic biomarkers in many diseases. However, the role of circRNAs in steroid-induced osteonecrosis of the femoral head (SONFH) has not been reported.

Methods

Secondary sequencing was performed to profile circRNA expression in peripheral blood samples from three SONFH patients and three healthy individuals. We confirmed our preliminary findings by qRT-PCR. Bioinformatics analysis was conducted to predict their functions.

Results

The result showed 345 dysregulated circRNAs. qRT-PCR of eight selected circRNAs preliminarily confirmed the results, which were consistent with RNA sequencing. Bioinformatics analyses were performed to predict the functions of circRNAs to target the genes of miRNAs and the networks of circRNA-miRNA-mRNA interactions.

Conclusions

This study provides a new and fundamental circRNA profile of SONFH and a theoretical basis for further studies on the functions of circRNAs in SONFH.

Guidelines for Acquisition, Interpretation, and Reporting of Whole-Body MRI in Myeloma: Myeloma Response Assessment and Diagnosis System (MY-RADS)

Acknowledging the increasingly important role of whole-body MRI for directing patient care in myeloma, a multidisciplinary, international, and expert panel of radiologists, medical physicists, and hematologists with specific expertise in whole-body MRI in myeloma convened to discuss the technical performance standards, merits, and limitations of currently available imaging methods. Following guidance from the International Myeloma Working Group and the National Institute for Clinical Excellence in the United Kingdom, the Myeloma Response Assessment and Diagnosis System (or MY-RADS) imaging recommendations are designed to promote standardization and diminish variations in the acquisition, interpretation, and reporting of whole-body MRI in myeloma and allow response assessment. This consensus proposes a core clinical protocol for whole-body MRI and an extended protocol for advanced assessments. Published under a CC BY 4.0 license. Online supplemental material is available for this article.

Unusual indication of Cell therapy for hip osteonecrosis after pregnancy

PURPOSE

Osteonecrosis is a rare event during or after pregnancy. Due to the low number of cases, there is no report of long-term results after conservative surgery in this population.

METHOD

From 1992 to 2010, 145 consecutive female patients with unilateral symptomatic (94 stage I and 51 stage II) left hip osteonecrosis (ON) related to pregnancy were treated between 4 and 16 months after delivery with percutaneous mesenchymal stem cell (MSC) injection obtained from bone marrow concentration. The average total number of MSCs (counted as number of colonies forming units-fibroblast) injected in the hip was 185 000 ± 65 000 cells (range 95 000-240 000 cells).

RESULTS

At the most recent follow-up (average 15 years after hip surgery, range 8-25 years), among the 145 hips included in the study, 4 hips (2.7%) had collapsed and were treated with total hip arthroplasty (THA). Thirty-two of the 94 stage I had progressed to stage II; and 4 of the 51 stage II had progressed to stage III and collapse. The other 141 hips (97.3%) were without collapse and pain free. On MRI, as percentage of the volume of the femoral head, the osteonecrosis had decreased from 34.5% pre-operatively to 6% at the most recent follow-up. For women who had other children after treatment, a subsequent pregnancy was not associated with osteonecrosis.

CONCLUSION

Patients with hip osteonecrosis following pregnancy had a low conversion rate to THA when treated early with cell therapy.