Relationship of α2-Macroglobulin with Steroid-Induced Femoral Head Necrosis: A Chinese Population-Based Association Study in Southeast China

[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.

Glucocorticoids promote steroid-induced osteonecrosis of the femoral head by down-regulating serum alpha-2-macroglobulin to induce oxidative stress and facilitate SIRT2-mediated BMP2 deacetylation

Our study investigated the possible molecular mechanism of glucocorticoid in steroid-induced osteonecrosis of the femoral head (SINFH) through regulating serum alpha-2-macroglobulin and SIRT2-mediated BMP2 deacetylation. Essential genes involved in glucocorticoid-induced SINFH were screened by transcriptome sequencing and analyzed by bioinformatics, followed by identifying downstream regulatory targets. Rat bone marrow mesenchymal stem cells were isolated and treated with methylprednisolone (MP) for in vitro cell experiments. Besides, a glucocorticoid-induced rat ONFH was established using the treatment of MP and LPS. ChIP-PCR detected the enrichment of SIRT2 in the promoter region of BMP2, and the deacetylation modification of SIRT2 on BMP2 was determined. Bioinformatics analysis revealed that glucocorticoids may induce ONFH through the SIRT2/BMP2 axis. In vitro cell experiments showed that glucocorticoids up-regulated SIRT2 expression in BMSCs by inducing oxidative stress, thereby promoting cell apoptosis. The up-regulation of SIRT2 expression may be due to the decreased ability of α2 macroglobulin to inhibit oxidative stress, and the addition of NOX protein inhibitor DPI could significantly inhibit SIRT2 expression. SIRT2 could promote histone deacetylation of the BMP2 promoter and inhibit its expression. In vitro cell experiments further indicated that knocking down SIRT2 could protect BMSC from oxidative stress and cell apoptosis induced by glucocorticoids by promoting BMP2 expression. In addition, animal experiments conducted also demonstrated that the knockdown of SIRT2 could improve glucocorticoid-induced ONFH through up-regulating BMP2 expression. Glucocorticoids could induce oxidative stress by down-regulating serum α2M to promote SIRT2-mediated BMP2 deacetylation, leading to ONFH.

Germline VWF/MPRIP and somatoplasm FGA variants synergically confer susceptibility to non-traumatic osteonecrosis of the femoral head

Non-traumatic osteonecrosis of the femoral head (ONFH) relies on multiple pathogenic factors, including intravascular coagulation, osteoporosis and lipid metabolism disorders. Despite extensively explored from various aspects, genetic mechanism underlying non-traumatic ONFH has not been fully elucidated. We randomly collected blood and necrotic tissue samples from 32 patients with non-traumatic ONFH as well as blood samples from 30 healthy individuals for whole exome sequencing (WES). Germline mutation and somatic mutation were analyzed to identify new potential pathogenic genes responsible for non-traumatic ONFH. Three genes might correlate with non-traumatic ONFH: VWF, MPRIP (germline mutations) and FGA (somatic mutations). Germline or somatic mutations in VWF, MPRIP and FGA correlate with intravascular coagulation, thrombosis, and consequently, ischemic necrosis of the femoral head.

Icariin regulates miR-23a-3p-mediated osteogenic differentiation of BMSCs via BMP-2/Smad5/Runx2 and WNT/β-catenin pathways in osteonecrosis of the femoral head

Icariin is commonly used for the clinical treatment of osteonecrosis of the femoral head (ONFH). miR-23a-3p plays a vital role in regulating the osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). The present study aimed to investigate the roles of icariin and miR-23a-3p in the osteogenic differentiation of BMSCs and an ONFH model. BMSCs were isolated and cultured in vitro using icariin-containing serum at various concentrations, and BMSCs were also transfected with a miR-23a inhibitor. The alkaline phosphatase (ALP) activity and cell viability as well as BMP-2/Smad5/Runx2 and WNT/β-catenin pathway-related mRNA and protein expression were measured in BMSCs. Additionally, a dual-luciferase reporter assay and pathway inhibitors were used to verify the relationship of icariin treatment/miR-23a and the above pathways. An ONFH rat model was established in vivo, and a 28-day gavage treatment and lentivirus transfection of miR-23a-3p inhibitor were performed. Then, bone biochemical markers (ELISA kits) in serum, femoral head (HE staining and Digital Radiography, DR) and the above pathway-related proteins were detected. Our results revealed that icariin treatment/miR-23a knockdown promoted BMSC viability and osteogenic differentiation as well as increased the mRNA and protein expression of BMP-2, BMP-4, Runx2, p-Smad5, Wnt1 and β-catenin in BMSCs and ONFH model rats. In addition, icariin treatment/miR-23a knockdown increased bone biochemical markers (ACP-5, BAP, NTXI, CTXI and OC) and improved ONFH in ONFH model rats. In addition, a dual-luciferase reporter assay verified that Runx2 was a direct target of miR-23a-3p. These data indicated that icariin promotes BMSC viability and osteogenic differentiation as well as improves ONFH by decreasing miR-23a-3p levels and regulating the BMP-2/Smad5/Runx2 and WNT/β-catenin pathways.

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.

Beware of Steroid-Induced Avascular Necrosis of the Femoral Head in the Treatment of COVID-19-Experience and Lessons from the SARS Epidemic

Summary

The recent outbreak of coronavirus disease 2019 (COVID-19) has become a global epidemic. Corticosteroids have been widely used in the treatment of severe acute respiratory syndrome (SARS), and the pathological findings seen in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are very similar to those observed in severe acute respiratory syndrome-related coronavirus (SARS-CoV) infection. However, the long-term use of corticosteroids (especially at high doses) is associated with potentially serious adverse events, particularly steroid-induced avascular necrosis of the femoral head (SANFH). In today’s global outbreak, whether corticosteroid therapy should be used, the dosage and duration of treatment, and ways for the prevention, early detection, and timely intervention of SANFH are some important issues that need to be addressed. This review aims to provide a reference for health care providers in COVID-19 endemic countries and regions.

Article Focus

Hormones are a double-edged sword. This review aims to provide a reference for health care providers in coronavirus disease 2019 (COVID-19) endemic countries and regions, especially with respect to the pros and cons of corticosteroid use in the treatment of patients with COVID-19.

Key Messages

In today’s global outbreak, whether corticosteroid therapy should be used, the dosage and duration of treatment, and ways for the prevention, early detection, and timely intervention of SANFH are some important issues that need to be addressed.

Strengths and Limitations

Since SARS was mainly prevalent in China at that time, many evidences in this paper came from the reports of Chinese scholars. There is a bias in the selection of data, which may ignore the differences in environment, race, living habits, medical level and so on. SANFH may be the result of multiple factors. Whether the virus itself is an independent risk factor for SANFH has not been confirmed. In this paper, through literature retrieval, some reference opinions on glucocorticoid usage, diagnosis and treatment of SANFH are given. However, due to the lack of large-scale research data support, it can not be used as the gold standard for the above problems.

Nontraumatic Osteonecrosis of the Femoral Head: Where Do We Stand Today?: A 5-Year Update

➢. Clinicians should exercise a high level of suspicion in at-risk patients (those who use corticosteroids, consume excessive alcohol, have sickle cell disease, etc.) in order to diagnose osteonecrosis of the femoral head in its earliest stage. ➢. Nonoperative treatment modalities have generally been ineffective at halting progression. Thus, nonoperative treatment is not appropriate in early stages when one is attempting to preserve the native joint, except potentially on rare occasions for small-sized, medially located lesions, which may heal without surgery. ➢. Joint-preserving procedures should be attempted in early-stage lesions to save the femoral head. ➢. Cell-based augmentation of joint-preserving procedures continues to show promising results, and thus should be considered as an ancillary treatment method that may improve clinical outcomes. ➢. The outcomes of total hip arthroplasty in the setting of osteonecrosis are excellent, with results similar to those in patients who have an underlying diagnosis of osteoarthritis.