Search

Ischemic osteonecrosis, particularly glucocorticoid-induced osteonecrosis of the femoral head (GIONFH), is primarily due to the dysfunction of osteogenesis and angiogenesis. miRNA, as a therapeutic system with immense potential, plays a vital role in the treatment of various diseases. However, due to the unique microenvironmental structure of bone tissue, especially in the case of GIONFH, where there is a deficiency in the vascular system, it is challenging to effectively target and deliver to the ischemic osteonecrosis area. A drug delivery system assisted by genetically engineered cell membranes holds promise in addressing the challenge of targeted miRNA delivery. Herein, we leverage the potential of miR-21 in modulating osteogenesis and angiogenesis to design an innovative biomimetic nanoplatform system. First, we employed metal-organic frameworks (MOFs) as the core structure to load miR-21-m (miR-21-m@MOF). The nanoparticles were further coated with the membrane of bone marrow mesenchymal stem cells overexpressing CXCR4 (CM-miR-21-m@MOF), enhancing their ability to target ischemic bone areas via the CXCR4-SDF1 axis. These biomimetic nanocomposites possess both bone-targeting and ischemia-guiding capabilities, actively targeting GIONFH lesions to release miR-21-m into target cells, thereby silencing PTEN gene and activating the PI3K-AKT signaling pathway to regulate osteogenesis and angiogenesis. This innovative miRNA delivery system provides a promising therapeutic avenue for GIONFH and potentially other related ischemic bone diseases. STATEMENT OF SIGNIFICANCE., Competing Interests: Declaration competing of interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Osteonecrosis (ON) of the femoral head (ONFH) is a devastating bone disease affecting over 20 million people worldwide. ONFH is caused by a disruption of the blood supply, leading to necrotic cell death and increased inflammation. Macrophages are the key cells mediating the inflammatory responses in ON. It is unclear what the dynamic phenotypes of macrophages are and what mechanisms may affect macrophage polarization and, therefore, the healing process. In our preliminary study, we found that there is an invasion of macrophages into the repair tissue during ON healing. Interestingly, in both ONFH patients and a mouse ON model, fat was co-labeled within macrophages using immunofluorescence staining, indicating the phagocytosis of fat by macrophages. To study the effects of fat phagocytosis on the macrophage phenotype, we set up an in vitro macrophage and fat co-culture system. We found that fat phagocytosis significantly decreased M1 marker expression, such as IL1β and iNOS, in macrophages, whereas the expression of the M2 marker Arg1 was significantly increased with fat phagocytosis. To investigate whether the polarization change is indeed mediated by phagocytosis, we treated the cells with Latrunculin A (LA, which inhibits actin polymerization and phagocytosis). LA supplementation significantly reversed the polarization marker gene changes induced by fat phagocytosis. To provide an unbiased transcriptional gene analysis, we submitted the RNA for bulk RNA sequencing. Differential gene expression (DGE) analysis revealed that the top upregulated genes were related to anti-inflammatory responses, while proinflammatory genes were significantly downregulated. Additionally, using pathway enrichment and network analyses (Metascape), we confirmed that gene-enriched categories related to proinflammatory responses were significantly downregulated in macrophages with fat phagocytosis. Finally, we validated the similar macrophage phenotype changes in vivo. To summarize, we discovered that fat phagocytosis occurs in both ONFH patients and an ON mouse model, which inhibits proinflammatory responses with increased anabolic gene expression in macrophages. This fat-phagocytosis-induced macrophage phenotype is consistent with the in vivo changes shown in the ON mouse model. Our study reveals a novel phagocytosis-mediated macrophage polarization mechanism in ON, which fills in our knowledge gaps of macrophage functions and provides new concepts in macrophage immunomodulation as a promising treatment for ON.

Background: Osteonecrosis of the femoral head caused by glucocorticoids (GIONFH) is a significant issue resulting from prolonged or excessive clinical glucocorticoid use. Astaxanthin, an orange-red carotenoid present in marine organisms, has been the focus of this study to explore its impact and mechanism on osteoblast apoptosis induced by dexamethasone (Dex) and GIONFH., Methods: In this experiment, bioinformatic prediction, molecular docking and dynamics simulation, cytotoxicity assay, osteogenic differentiation, qRT-PCR analysis, terminal uridine nickend labeling (TUNEL) assay, determination of intracellular ROS, mitochondrial function assay, immunofluorescence, GIONFH rat model construction, micro-computed tomography (micro-CT) scans were performed., Results: Our research demonstrated that a low dose of astaxanthin was non-toxic to healthy osteoblasts and restored the osteogenic function of Dex-treated osteoblasts by reducing oxidative stress, mitochondrial dysfunction, and apoptosis. Furthermore, astaxanthin rescued the dysfunction in poor bone quality, bone metabolism and angiogenesis of GIONFH rats. The mechanism behind this involves astaxanthin counteracting Dex-induced osteogenic damage by activating the Nrf2 pathway., Conclusion: Astaxanthin shields osteoblasts from glucocorticoid-induced oxidative stress and mitochondrial dysfunction via Nrf2 pathway activation, making it a potential therapeutic agent for GIONFH treatment., (© 2024. The Author(s).)

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., (© 2024 The Author(s). Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

In this comprehensive case report, we examine a 29-year-old male who suffered a high-energy vehicular accident, resulting in a type III Hawkins fracture of the talus. This specific fracture type is critically associated with a greater than 90% risk of progressing to avascular necrosis (AVN) of the talus, a severe and debilitating condition. Alongside this, the patient sustained fractures of the medial and lateral malleolus. Due to extensive swelling and severe circulatory disorders, an immediate emergency surgical procedure was necessitated, employing nail fixation as a stabilizing intervention. Over the course of 12 months following the surgery, despite routine post-operative imaging including X-rays and computed tomography (CT) scans, the patient continued to experience significant pain and impairment. This condition led to further investigations, culminating in a magnetic resonance imaging (MRI) that revealed an area of 19.8∕20.9 mm of AVN on the talus dome's upper-lateral facet. Interestingly, earlier CT scans had indicated multiple osteitic lesions, but these findings lacked a clear clinical correspondence, presenting a diagnostic challenge. To resolve this ambiguity and to definitively distinguish between necrosis and infection, a targeted histopathological analysis was deemed necessary. This analysis was conducted on a bone fragment extracted during a follow-up surgical procedure for nail removal. The results from this analysis present an area of bone and myeloid tissue necrosis unequivocally confirming the presence of AVN, effectively ruling out osteitis as a potential diagnosis. This critical diagnostic clarification allowed for a shift in therapeutic strategy, enabling the initiation of a more focused and potentially curative treatment regimen.

Glucocorticoid-induced osteonecrosis of the femoral head (GONFH) is a common refractory joint disease characterized by bone damage and the collapse of femoral head structure. However, the exact pathological mechanisms of GONFH remain unknown. Here, we observed abnormal osteogenesis and adipogenesis associated with decreased β-catenin in the necrotic femoral head of GONFH patients. In vivo and in vitro studies further revealed that glucocorticoid exposure disrupted osteogenic/adipogenic differentiation of bone marrow mesenchymal cells (BMSCs) by inhibiting β-catenin signaling in glucocorticoid-induced GONFH rats. Col2 + lineage largely contributes to BMSCs and was found an osteogenic commitment in the femoral head through 9 mo of lineage trace. Specific deletion of β-catenin gene ( Ctnnb1 ) in Col2 + cells shifted their commitment from osteoblasts to adipocytes, leading to a full spectrum of disease phenotype of GONFH in adult mice. Overall, we uncover that β-catenin inhibition disrupting the homeostasis of osteogenic/adipogenic differentiation contributes to the development of GONFH and identify an ideal genetic-modified mouse model of GONFH., Competing Interests: CX, HX, LF, JC, WY, DF, XW, BH, LX, CW, PT, DC, PW, HJ No competing interests declared, (© 2023, Xia, Xu et al.)

Osteonecrosis of the femoral head (ONFH), a progressive pathological process of femoral head ischemia and osteocyte necrosis, is a refractory orthopedic disease caused by multiple etiologies and there is no complete cure at present. With the extension of ONFH duration, osteocyte apoptosis and trabecular bone loss can decrease the load-bearing capacity of the femoral head, which leads to the collapse of the articular cartilage and subchondral bone. Therefore, an urgent clinical need exists to develop effective treatment strategies of early-stage ONFH for maintaining the hip joint function and preventing femoral head collapse. In recent years, extensive attention has been paid to the application of diverse biomaterials in treating early ONFH for sustaining the normal morphology and function of the autologous femoral head, and slowing disease progression. Herein, we review the research progress of bone grafts, metallic materials, bioceramics, bioglasses and polymer materials for early ONFH treatment, and discuss the biological mechanisms of bone repair and regeneration in the femoral-head necrotic area. We propose suggestions for future research directions, from a special perspective of improving the local microenvironment in femoral head by facilitating vessel-associated osteoclasts (VAOs) generation and coupling of bone-specific angiogenesis and osteogenesis, as well as inhibiting bone-associated osteoclasts (BAOs) and BAO-mediated bone resorption. This review can provide ideas for the research, development, and clinical application of biomaterials for treating early ONFH. STATEMENT OF SIGNIFICANCE: We believe that at least three aspects of this manuscript make it interesting to readers of the Acta Biomaterialia. First, we briefly summarize the incidence, pathogenesis, risk factors, classification criteria and treatment of early osteonecrosis of the femoral head (ONFH). Second, we review the research progress in biomaterials for early ONFH treatment and the biological mechanisms of bone repair and regeneration in femoral-head necrotic area. Third, we propose future research progress on improving the local microenvironment in femoral head by facilitating vessel-associated osteoclasts generation and coupling of bone-specific angiogenesis and osteogenesis, as well as inhibiting bone-associated osteoclasts and bone resorption. We hope this review can provide ideas for the research, development, and clinical application of biomaterials for treating early ONFH., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Glucocorticoid (GC)-induced osteonecrosis of the femoral head (ONFH) is a serious complication of glucocorticoid treatment and is characterized by dysfunctional bone reconstruction at necrotic sites. Our previous study confirmed the protective potential of necrostatin-1, a selective blocker of necroptosis, in glucocorticoid-induced osteoporosis. In this study, rat models of GC-induced ONFH were established to evaluate the effects of necrostatin-1 on osteonecrotic changes and repair processes. Osteonecrosis was verified by histopathological staining. An analysis of trabecular bone architecture was performed to evaluate osteogenesis in the osteonecrotic zone. Then, necroptotic signaling molecules such as RIP1 and RIP3 were examined by immunohistochemistry. Histopathological observations indicated that necrostatin-1 administration reduced the incidence of osteonecrosis and the osteogenic response in subchondral areas. Additionally, bone histomorphometry demonstrated that necrostatin-1 intervention could restore bone reconstruction in the necrotic zone. The protective mechanism of necrostatin-1 was related to the inhibition of RIP1 and RIP3. Necrostatin-1 administration alleviated GC-induced ONFH in rats by attenuating the formation of necrotic lesions, recovering the function of osteogenesis, and suppressing glucocorticoid-induced osteocytic necroptosis by inhibiting the expression of RIP1 and RIP3., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

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., (© 2023. The Author(s).)

Aim: The purpose of this study was to investigate the functions of exosomal miR-150 derived from bone marrow mesenchymal stem cells in osteonecrosis of the femoral head (ONFH). Materials & methods: Cell viability and apoptosis were detected using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and flow cytometry. Alizarin red staining was performed to detect calcium deposits. A rat model was established to assess the effects of exosomal miR-150 on ONFH in vivo . Results: Exosomes or exosomal miR-150 derived from bone marrow mesenchymal stem cells inhibited TNF-α-induced osteoblast apoptosis and promoted osteogenic differentiation and autophagy. Exosomal miR-150 suppressed apoptosis and induced autophagy in TNF-α-treated osteoblasts by regulating the GREM1/NF-κB axis. Exosomal miR-150 also improved the pathological features of ONFH in vivo . Conclusion: Exosomal miR-150 alleviates ONFH by mediating the GREM1/NF-κB axis. This study provides a potential therapeutic strategy for ONFH.

Alcohol-induced osteonecrosis of the femoral head (ONFH) is a disabling disease with a high incidence and elusive pathogenesis. Here, we used single-cell RNA sequencing to explore the transcriptomic landscape of mid- and advanced-stage alcohol-induced ONFH. Cells derived from age-matched hip osteoarthritis and femoral neck fracture samples were used as control. Our bioinformatics analysis revealed the disorder of osteogenic-adipogenic differentiation of stromal cells in ONFH and altered regulons such as MEF2C and JUND. In addition, we reported that one of the endothelial cell clusters with ACKR1 expression exhibited strong chemotaxis and a weak angiogenic ability and expanded with disease progression. Furthermore, ligand-receptor-based cell-cell interaction analysis indicated that ACKR1+ endothelial cells might specifically communicate with stromal cells through the VISFATIN and SELE pathways, thus influencing stromal cell differentiation in ONFH. Overall, our data revealed single cell transcriptome characteristics in alcohol-induced ONFH, which may contribute to the further investigation of ONFH pathogenesis., (© 2022. The Author(s).)

Osteonecrosis of the femoral head (ONFH) is a debilitating disease that is closely associated with the clinical application of high-dose glucocorticoids. Elevated oxidative stress contributes to the pathophysiological changes observed in ONFH. The lack of effective treatments besides surgical intervention highlights the importance of finding novel therapeutics. Our previous studies demonstrated that D7, a cyclic polypeptide, enhances the adhesion, expansion, and proliferation of bone marrow mesenchymal stem cells (BMSCs). Therefore, in this study, we investigated the therapeutic effects of D7 against ONFH in BMSCs and evaluated the underlying mechanisms. First, we screened for ONFH risk factors. Then, we applied D7 treatment to steroid-induced ONFH (SONFH) in an in vitro model produced by dexamethasone (DEX) to further elucidate the underlying mechanisms. We found negative correlations among oxidative stress marker expression, growth differentiation factor 15 (GDF15) levels, and ONFH. Furthermore, we demonstrated that DEX inhibited the proliferation and induced apoptosis of BMSCs by suppressing GDF15/AKT/mammalian target of rapamycin (mTOR) signaling. D7 alleviated DEX-induced BMSCs injury and restored the chondrogenic function of BMSCs by activating GDF15/AKT/mTOR signaling. In addition, DEX-induced excessive reactive oxygen species (ROS) generation was an upstream trigger of GDF15-mediated signaling, and D7 ameliorated this DEX-induced redox imbalance by restoring the expression of antioxidants, including superoxide dismutase (SOD) 1, SOD2, and catalase, via regulation of GDF15 expression. In conclusion, our findings revealed the potential therapeutic effects of D7 in SONFH and showed that this protective function may be mediated via inhibition of DEX-induced ROS and activation of GDF15/AKT/mTOR signaling, thereby providing insights into the potential applications of D7 in SONFH treatment., Competing Interests: The authors declare that they have no competing interests., (Copyright © 2022 Jiazheng Chen et al.)

Osteonecrosis of the jaws (ONJ) usually has a clear etiology. Local infection or trauma, radiotherapy and drugs that disrupt the vascular supply or bone turnover in the jaws are its major contributors. The thrombotic occlusion of the bone's venous outflow that occurs in individuals with hereditary thrombophilia and/or hypofibrinolysis has a less known impact on jaw health and healing capability. Our research provides the most comprehensive, up-to-date and systematized information on the prevalence and significance of hereditary thrombophilia and/or hypofibrinolysis states in ONJ. We found that hereditary prothrombotic abnormalities are common in patients with ONJ refractory to conventional medical and dental treatments. Thrombophilia traits usually coexist with hypofibrinolysis traits. We also found that frequently acquired prothrombotic abnormalities coexist with hereditary ones and enhance their negative effect on the bone. Therefore, we recommend a personalized therapeutic approach that addresses, in particular, the modifiable risk factors of ONJ. Patients will have clear benefits, as they will be relieved of persistent pain and repeated dental procedures.

MicroRNAs (miRNAs) are a class of small (20-24 nucleotides), highly conserved, non-coding RNA molecules whose main function is the post-transcriptional regulation of gene expression through sequence-specific manners, such as mRNA degradation or translational repression. Since these key regulatory molecules are implicated in several biological processes, their altered expression affects the preservation of cellular homeostasis and leads to the development of a wide range of pathologies. Over the last few years, relevant investigations have elucidated that miRNAs participate in different stages of bone growth and development. Moreover, the abnormal expression of these RNA molecules in bone cells and tissues has been significantly associated with the progression of numerous bone diseases, including osteoporosis, osteosarcoma, osteonecrosis and bone metastasis, among others. In fact, miRNAs regulate multiple pathological mechanisms, including altering either osteogenic or osteoblast differentiation, metastasis, osteosarcoma cell proliferation, and bone loss. Therefore, in this present review, aiming to impulse the research arena of the biological implications of miRNA transcriptome in bone diseases and to explore their potentiality as a theragnostic target, we summarize the recent findings associated with the clinical significance of miRNAs in these ailments.

An important objective of vascularized tissue regeneration is to develop agents for osteonecrosis. We aimed to identify the pro-angiogenic and osteogenic efficacy of adipose tissue-derived (AD) pericytes combined with Nel-like protein-1 (NELL-1) to investigate the therapeutic effects on osteonecrosis. Tube formation and cell migration were assessed to determine the pro-angiogenic efficacy. Vessel formation was evaluated in vivo using the chorioallantoic membrane assay. A mouse model with a 2.5 mm necrotic bone fragment in the femoral shaft was used as a substitute for osteonecrosis in humans. Bone formation was assessed radiographically (plain radiographs, three-dimensional images, and quantitative analyses), and histomorphometric analyses were performed. To identify factors related to the effects of NELL-1, analysis using microarrays, qRT-PCR, and Western blotting was performed. The results for pro-angiogenic efficacy evaluation identified synergistic effects of pericytes and NELL-1 on tube formation, cell migration, and vessel formation. For osteogenic efficacy analysis, the mouse model for osteonecrosis was treated in combination with pericytes and NELL-1, and the results showed maximum bone formation using radiographic images and quantitative analyses, compared with other treatment groups and showed robust bone and vessel formation using histomorphometric analysis. We identified an association between FGF2 and the effects of NELL-1 using array-based analysis. Thus, combinatorial therapy using AD pericytes and NELL-1 may have potential as a novel treatment for osteonecrosis.

Background: The number of articles of clinical and basic research for osteonecrosis of the femoral head (ONFH) is increasing, yet, to our knowledge, there is still a lack of bibliometric analysis on ONFH articles. The purpose of this study was to identify the top 100 cited (T100) articles related to ONFH research and to analyze the characteristics and qualities of these articles., Methods: The T100 articles on ONFH were retrieved from the Web of Science database. The information about each article including citations, titles, authors, journals, countries, institutions, and keywords was recorded for bibliometric analysis., Results: The T100 articles related to ONFH were mainly published from 1991 to 2010 ( n = 70) and were originated from 24 countries. The USA, China, and Japan were the most productive countries in this regard. The most prolific institution was the University of Pennsylvania from the USA with 6 publications and 742 citations. The most cited article was published in 1995 by Professor Steinberg ME. The five most frequently occurring keywords were "femoral head," "osteonecrosis," "core decompression," "total hip arthroplasty," and "follow up." The keywords like "bone tissue engineering" and "extracorporeal shock wave" have emerged in recent years., Conclusions: The USA, China, and Japan contributed greatly in terms of the T100 articles. The outcomes of core decompression and total hip arthroplasty gathered the most research interests. In recent years, bone tissue engineering and extracorporeal shock wave have become new trends. However, the mechanism of ONFH is still unclear., Competing Interests: The authors declare that there is no conflict of interest regarding the publication of this article., (Copyright © 2021 Yumin Zhang et al.)

This study aimed to evaluate the efficacy and safety of bone cement-augmented pedicle screw fixation for stage III Kümmell disease. Twenty-five patients with stage III Kümmell disease who received bone cement-augmented pedicle screw fixation at the First Affiliated Hospital of Guangzhou University of Chinese Medicine between June 2009 and December 2015 were enrolled. All patients were females with a history of osteoporosis. The vertebral Cobb angle (V-Cobb angle), the fixed segment Cobb Angle (S-Cobb angle), pelvic parameters, visual Analogue Scale (VAS) score, and Oswestry Disability Index (ODI) were assessed preoperatively, postoperatively and at the final follow-up. Complications, loosening rate, operation time, and intraoperative bleeding were recorded. The average lumbar vertebral density T-value was - 3.68 ± 0.71 SD, and the average age was 71.84 ± 5.39. The V-Cobb angle, S-Cobb angle, and Sagittal Vertical Axis (SVA) were significantly smaller postoperatively compared to the preoperative values. The VAS and ODI at 1 month after surgery were 3.60 ± 1.00 and 36.04 ± 6.12%, respectively, which were both significantly lower than before surgery (VAS: 8.56 ± 1.04, ODI: 77.80 ± 6.57%). Bone cement-augmented pedicle screw fixation is a safe and effective treatment for stage III Kümmell disease. It can effectively correct kyphosis, restore and maintain sagittal balance, and maintain spinal stability.

Non-traumatic osteonecrosis of the femoral head (ONFH) usually affects adults younger than 50 years and frequently leads to femoral head collapse and subsequent arthritis of the hip. It is becoming more prevalent along with increasing use of corticosteroids for the adjuvant therapy of leukemia and other myelogenous diseases as well as management of organ transplantation. This review updated knowledge on the pathogenesis, classification criteria, staging system, and treatment of ONFH., Competing Interests: The authors have no potential conflicts of interest to disclose., (© 2021 The Korean Academy of Medical Sciences.)

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., (© 2021 The Authors. Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

Glucocorticoids (GCs) are used in treating viral infections, acute spinal cord injury, autoimmune diseases, and shock. Several patients develop GC-induced osteonecrosis of the femoral head (ONFH). However, the pathogenic mechanisms underlying GC-induced ONFH remain poorly understood. GC-directed bone marrow mesenchymal stem cells (BMSCs) fate is an important factor that determines GC-induced ONFH. At high concentrations, GCs induce BMSC apoptosis by promoting oxidative stress. In the present study, we aimed to elucidate the molecular mechanisms that relieve GC-induced oxidative stress in BMSCs, which would be vital for treating ONFH. The endocannabinoid system regulates oxidative stress in multiple organs. Here, we found that monoacylglycerol lipase (MAGL), a key molecule in the endocannabinoid system, was significantly upregulated during GC treatment in osteoblasts both in vitro and in vivo. MAGL expression was positively correlated with expression of the NADPH oxidase family and apoptosis-related proteins. Functional analysis showed that MAGL inhibition markedly reduced oxidative stress and partially rescued BMSC apoptosis. Additionally, in vivo studies indicated that MAGL inhibition effectively attenuated GC-induced ONFH. Pathway analysis showed that MAGL inhibition regulated oxidative stress in BMSCs via the Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. The expression of Nrf2, a major regulator of intracellular antioxidants, was upregulated by inhibiting MAGL. Nrf2 activation can mimic the effect of MAGL inhibition and significantly reduce GC-induced oxidative damage in BMSCs. The beneficial effects of MAGL inhibition were attenuated after the blockade of the Keap1/Nrf2 antioxidant signaling pathway. Notably, pharmacological blockade of MAGL conferred femoral head protection in GC-induced ONFH, even after oxidative stress responses were initiated. Therefore, MAGL may represent a novel target for the prevention and treatment of GC-induced ONFH., (© 2021 The Authors. Clinical and Translational Medicine published by John Wiley & Sons Australia, Ltd on behalf of Shanghai Institute of Clinical Bioinformatics.)

Purpose: To evaluate the osseous anatomy of the proximal femur extracted from a 3D-MRI volumetric interpolated breath-hold (VIBE) sequence using either a Dixon or water excitation (WE) fat suppression method, and to measure the overall difference using CT as a reference standard., Material and Methods: This retrospective study reviewed imaging of adult patients with hip pain who underwent 3D hip MRI and CT. A semi-automatically segmented CT model served as the reference standard, and MRI segmentation was performed manually for each unilateral hip joint. The differences between Dixon-VIBE-3D-MRI vs. CT, and WE-VIBE-3D-MRI vs. CT, were measured. Equivalence tests between Dixon-VIBE and WE-VIBE models were performed with a threshold of 0.1 mm. Bland-Altman plots and Lin's concordance-correlation coefficient were used to analyze the agreement between WE and Dixon sequences. Subgroup analyses were performed for the femoral head/neck, intertrochanteric, and femoral shaft areas., Results: The mean and maximum differences between Dixon-VIBE-3D-MRI vs. CT were 0.2917 and 3.4908 mm, respectively, whereas for WE-VIBE-3D-MRI vs. CT they were 0.3162 and 3.1599 mm. The mean differences of the WE and Dixon methods were equivalent (P = 0.0292). However, the maximum difference was not equivalent between the two methods and it was higher in WE method. Lin's concordance-correlation coefficient showed poor agreement between Dixon and WE methods. The mean differences between the CT and 3D-MRI models were significantly higher in the femoral shaft area (P = 0.0004 for WE and P = 0.0015 for Dixon) than in the other areas. The maximum difference was greatest in the intertrochanteric area for both techniques., Conclusion: The difference between 3D-MR and CT models were acceptable with a maximal difference below 3.5mm. WE and Dixon fat suppression methods were equivalent. The mean difference was highest at the femoral shaft area, which was off-center from the magnetization field., Competing Interests: There are no relative declarations relating to employment, consultancy, patents, products in development, or marketed products. The commercial affiliation, ANYMEDI, does not alter our adherence to PLOS ONE policies on sharing data and materials.

Background: Osteonecrosis of the femoral head (ONFH) seriously affects the quality of life and labor ability of patients. It is urgent and vital to find the methods for necrosis clinical treatment., Objective: This study aims to study the potential protective effects of Alendronate in the early stage of femur head necrosis., Methods: Ten clinal ONFH tissue samples were employed. H&E staining was employed for the observation of the pathological characteristics of ONFH. The rat model (n=12) was established by the treatment of liquid nitrogen and then treated with Alendronate. The protein expression of BMP2, EIF2AK3, EIF2A and ATF4 were detected via Western blotting and IHC., Results: Fibrin and necrotizing granulation tissue were observed in ONFH tissues with lymphocytes and plasma cells infiltrating in the necrotic area, exhibiting the inflammatory muscle with abnormal shape and color. In the Model group, the BMP2 and ATF4 were mainly distributed in the cell boundaries. The relative protein expression of BMP2, EIF2AK3, EIF2A, ATF4 was decreased in the Model group, compared to the NC group, which was partially recovered by the Alendronate application., Conclusion: Alendronate application partially reversed the suppression of expression of BMP2, EIF2AK3, EIF2A, ATF4 caused by liquid nitrogen. Alendronate could be a promising strategy of curing ONFH via targeting BMP2/EIF2AK3/EIF2A/ATF4 pathway., Competing Interests: All authors declare no conflicts of interest., (© 2021 Rong et al.)

Although various studies have proposed vascular and mechanical factors, the etiology of Kienböck disease is unknown. Kienböck theorized that lunatomalacia resulted from traumatic disruption of blood supply and bony nutrition to the lunate. Extraosseous supply to the lunate, as far as volar or dorsal vessels are concerned, is still controversial. This study evaluated the extraosseous nutrient foramina from the dorsal and volar aspects of lunate specimens. A total of 913 specimens from the Hamann-Todd Osteological Collection in Cleveland, Ohio, were examined. The nutrient artery foramina on left and right lunate specimens were examined from dorsal and volar aspects. The number of nutrient artery foramen was tabulated. Age, sex, and race data were collected. Specimens were divided into groups according to the number of nutrient artery foramina, and the dorsal and volar foramina were compared. The average number of foramina on the dorsal aspect of the lunate (1.71) was greater than the volar aspect (1.64), except in specimens younger than 35 years. A greater number of specimens had 3 or more foramina on the dorsal side compared with the volar aspect. Based on this study, there was significant contribution of dorsal arterial vessels to the blood supply of lunate specimens older than 35 years, which contrasts with findings in earlier studies. The disruption of dorsal intercarpal and radiocarpal ligaments leading to the disruption of the dorsal arterial arches may contribute to vascular insufficiency of the lunate and should be evaluated further in the etiopathogenesis of Kienböck disease. [ Orthopedics . 2021;44(2):e243-e247.].

Medication-related osteonecrosis of the jaw (MRONJ) is a rare but serious adverse drug effect. There are multiple hypotheses to explain the development of MRONJ. Reduced bone remodeling and infection or inflammation are considered central to the pathogenesis of MRONJ. In recent years, increasing evidence has shown that bisphosphonates (BPs)-mediated immunity dysfunction is associated with the pathophysiology of MRONJ. In a healthy state, mucosal immunity provides the first line of protection against pathogens and oral mucosal immune cells defense against potentially invading pathogens by mediating the generation of protective immunoinflammatory responses. In addition, the immune system takes part in the process of bone remodeling and tissue repair. However, the treatment of BPs disturbs the mucosal and osteo immune homeostasis and thus impairs the body's ability to resist infection and repair from injury, thereby adding to the development of MRONJ. Here, we present the current knowledge about immunity dysfunction to shed light on the role of local immune disorder in the development of MRONJ., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Zhang, Gao, Ren, Li, Zheng, Li, Jiang, Yang and Zhi.)

Introduction: Recently, the efficacy of mesenchymal stem cells (MSCs) mediated by their tissue repair and anti-inflammatory actions in the prevention and therapy of various disorders has been reported. In this research, our attention was focused specifically on the prevention and therapy of glucocorticoid-induced osteonecrosis. We investigated the stress resistance of MSC against glucocorticoid administration and hypoxic stress, which are factors known to induce osteocytic cell death. Materials and Methods: Mouse bone cells (MLO-Y4) and bone-marrow derived mouse MSCs were exposed to dexamethasone (Dex), hypoxia of 1% oxygen or both in vitro . Mitochondrial membrane potentials were estimated by mitochondria labeling with a cell-permeant probe (Mito tracker red); expression of these apoptosis-inducing molecules, oxidative stress marker (8-hydroxy-2'-deoxyguanosine), caspase-3, -9, and two apoptosis-inhibiting molecules, energy-producing ATP synthase (ATP5A) and X-linked inhibitor of apoptosis protein (XIAP), were analyzed by both immunofluorescence and western blot. Results: With exposure to either dexamethasone or hypoxia, MLO-Y4 showed reduced mitochondrial membrane potential, ATP5A and upregulation of 8-OHdG, cleaved caspases and XIAP. Those changes were significantly enhanced by treatment with dexamethasone plus hypoxia. In MSCs, however, mitochondrial membrane potentials were preserved, while no significant changes in the pro-apoptosis or anti-apoptosis molecules analyzed were found even with exposure to both dexamethasone and hypoxia. No such effects induced by treatment with dexamethasone, hypoxia, or both were demonstrated in MSCs at all. Discussion: In osteocyte cells subjected to the double stresses of glucocorticoid administration and a hypoxic environment osteocytic cell death was mediated via mitochondria. In contrast, MSC subjected to the same stressors showed preservation of mitochondrial function and reduced oxidative stress. Accordingly, even under conditions sufficiently stressful to cause the osteocytic cell death in vivo , it was thought that the function of MSC could be preserved, suggesting that in the case of osteonecrosis preventative and therapeutic strategies incorporating their intraosseous implantation may be promising., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Rationale: Osteonecrosis (ON) is a devastating illness that leads to bone ischemia and potential joint destruction. Systemic lupus erythematosus (SLE) is a chronic, autoimmune disease, with multi-system involvement which is closely associated with occurrence of ON. Multifocal ON, with an estimated morbidity of 3% in SLE patients, is extremely rare in juvenile subjects., Patient Concerns: A 13.3-year-old female SLE patient was admitted to hospital 20 months following the SLE diagnosis because of a sudden aggravation of sore knees. She suffered from double knee joint pain and her left knee joint showed typical signs of inflammation including redness, swelling, heat, and pain., Diagnoses: The SLE patient was diagnosed with multifocal ON of her knee joint based on magnetic resonance imaging findings of bone destruction and osteoproliferation at the bilateral distal femur and proximal tibia., Interventions: The patient received high-dose methylprednisolone and intravenous cyclophosphamide pulse therapies for controlling active lupus and nephritis. Oral calcitriol and dipyridamole were administered to alleviate knee pain and inhibit thrombi formation, thereby suppressing ON progress., Outcomes: Three weeks following the treatment, the swelling in patient's left knee subsided. Her self-reporting pain score decreased from 9 to 4 and walking time increased from 45minutes to 90minutes per day. Nearly 5 weeks later, the pain in bilateral knee joints disappeared and the patient could walk without difficulties., Lessons: This patient is the youngest SLE patient who developed multifocal ON based on the reported literature. It suggests that ON can occur in young SLE patients. A combination of internal and external risk factors can promote the development of ON. The balanced approach to the application of corticosteroids and immunosuppressors in the treatment of SLE and prevention of ON is a challenging problem that deserves further exploration., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Rationale: Osteonecrosis of the femoral head is a common orthopedic disease. Some studies have shown that osteonecrosis of the femoral head is related to susceptibility genes, but there are few reports of familial osteonecrosis of the femoral head. Here, we reported two first-degree relatives with osteonecrosis of the femoral head., Patient Concerns: A 27-year-old man with bilateral hip pain was diagnosed with osteonecrosis of the femoral head. The patient's mother also had a history of this disease., Diagnoses: Whole exome sequencing revealed the same mutation (c.15+3G>A) in the insulin-like growth factor 1 (IGF1) gene of the proband and his mother but not in his elder sister., Interventions: The patient underwent bilateral total hip arthroplast., Outcomes: The patient recovered well, and was discharged., Lessons: We found a heterozygous mutation (c.15+3G>A) in IGF1 in this family, which could be related to osteonecrosis of the femoral head. Early genetic counseling and gene locus detection could, thus, prove helpful for early diagnosis of osteonecrosis of the femoral head., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Although corticosteroids and alcohol are two major risk factors for nontraumatic osteonecrosis of the femoral head (NONFH), the effects of other factors have rarely been studied, thereby making early diagnosis and treatment of NONFH difficult. This study aimed to develop and validate a nomogram to NONFH, but patients with alcohol- and steroid-related NONFH are not at all taken into account in this study. A training cohort of 790 patients (n = 434, NONFH; n = 356, femoral neck fractures [non-NONFH]) diagnosed in our hospital from January 2011 to December 2016 was used for model development. A least absolute shrinkage and selection operator (lasso) regression model was used for date dimension reduction and optimal predictor selection. A predictive model was developed from univariate and multivariate logistic regression analyses. Performance characterisation of the resulting nomogram included calibration, discriminatory ability, and clinical usefulness. After internal validation, the nomogram was further evaluated in a separate cohort of 300 consecutive patients included between January 2017 and December 2018. The simple prediction nomogram included five predictors from univariate and multivariate analyses, including gender, total cholesterol levels, triglyceride levels, white blood cell count, and platelet count. Internal validation showed that the model had good discrimination [area under the receiver operating characteristic curve (AUC) = 0.80] and calibration. Good discrimination (AUC = 0.81) and calibration were preserved in the validation cohort. Decision curve analysis showed that the predictive nomogram was clinically useful. The simple diagnostic nomogram, which combines demographic data and laboratory blood test results, was able to quantify the probability of NONFH in cases of early screening and diagnosis.

Long non‑coding RNAs (lncRNAs) are crucial for the occurrence and development of numerous diseases. Although lncRNAs are involved in the biological activities of stem cells and play crucial roles in stem cell differentiation, the expression of specific lncRNAs during human bone marrow‑derived mesenchymal stem cell (hBMSC) osteogenic differentiation in osteonecrosis of the femoral head (ONFH) and their regulatory roles have not yet been fully elucidated. To the best of our knowledge, the present study is the first to characterize lncRNA expression profiles during hBMSC osteogenic differentiation in ONFH using microarray analysis and RT‑qPCR to confirm the microarray data. A total of 24 downregulated and 24 upregulated lncRNAs were identified and the results of RT‑qPCR were found to be consistent with those of microarray analysis. Bioinformatics analyses, using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, were conducted to explore the possible mechanisms and identify the signaling pathways that the lncRNAs are involved in. GO analysis revealed significant changes in the intracellular organelle, Ras protein signal transduction and transferase activity. KEGG pathway analysis revealed that the lncRNAs were closely associated with fatty acid metabolism, apoptosis and the TGF‑β signaling pathway. The overexpression of MAPT antisense RNA 1 (MAPT‑AS1) was found to promote osteogenesis and inhibit the adipogenesis of hBMSCs at the cellular and mRNA levels. On the whole, the findings of the present study identified the lncRNAs and their roles in hBMSCs undergoing osteogenic differentiation in ONFH and provide a new perspective for the pathogenesis of ONFH.

Childhood-onset systemic lupus erythematosus (SLE) is associated with greater disease activity, more aggressive course, and high rates of organ damage. The prolonged use of corticosteroids in childhood SLE contributes to increased morbidity, including avascular necrosis (AVN). We conducted this retrospective study using claims data from the Taiwan National Health Insurance Research Database, enrolling 1,472 children with newly-diagnosed SLE between 2005 and 2013. The mean age at the diagnosis of SLE was 15.5 ± 3.3 years, and the female to male ratio was 6.2:1. Thirty-nine patients (2.6%) developed symptomatic AVN during a mean follow-up of 4.6 ± 2.5 years. In multivariate analysis, the risk of AVN was higher in the patients with a daily prednisolone dose between 7.5 mg and 30 mg (HR 7.435, 95% CI 2.882-19.178, p < 0.001) and over 30 mg (HR 9.366, 95% CI 2.225-39.418, p = 0.002) than in those with a dose ≤ 7.5 mg/day. In addition, AVN was inversely correlated with the use of hydroxychloroquine > 627 days (HR 0.335, 95% CI 0.162-0.694, p = 0.003). In conclusion, high daily doses of prednisolone were associated with a significant risk of AVN, whereas the use of hydroxychloroquine > 627 days conferred an advantage. We suggest that the judicious use of corticosteroids combined with hydroxychloroquine might be a promising preventive strategy for AVN.

Mitochondrial injury has recently been implicated in the pathogenesis of glucocorticoid-induced osteonecrosis. Using cultured osteocytes and a rabbit model, we investigated the possibility that taurine (TAU), which is known to play a role in the preservation of mitochondrial function, might also prevent the development of osteonecrosis. To reduplicate the intraosseous environment seen in glucocorticoid-induced osteonecrosis, dexamethasone (Dex) was added to MLO-Y4 cultured in 1% hypoxia (H-D stress environment). An in vitro study was conducted in which changes in mitochondrial transcription factor A (TFAM), a marker of mitochondrial function, and ATP5A produced by mitochondria, induced by the presence/absence of taurine addition were measured. To confirm the effect of taurine in vivo, 15 Japanese White rabbits were administered methylprednisolone (MP) 20 mg/kg as a single injection into the gluteus muscle (MP+/TAU- group), while for 5 consecutive days from the day of MP administration, taurine 100 mg/kg was administered to 15 animals (MP+/TAU+ group). As a control 15 untreated rabbits were also studied. The rabbits in each of the groups were sacrificed on the 14th day after glucocorticoid administration, and the bilateral femora were harvested. Histopathologically, the incidence of osteonecrosis was quantified immunohistochemically by quantifying TFAM and ATP5A expression. In the rabbits exposed to an H-D stress environment and in MP+/TAU- group, TFAM and ATP5A expression markedly decreased. With addition of taurine in the in vitro and in vivo studies, the expression of TFAM and ATP5A was somewhat decreased as compared with Dex-/hypoxia- or MP-/TAU- group, while improvement was noted as compared with Dex+/hypoxia+ or MP+/TAU- group. In rabbits, the incidence of osteonecrosis was 80% in MP+/TAU- group, in contrast to 20% in the taurine administered group (MP+/TAU+), representing a significant decrease. Since taurine was documented to exert a protective effect on mitochondrial function by inhibiting the mitochondrial dysfunction associated with glucocorticoid administration, we speculated that it might also indirectly help to prevent the development of osteonecrosis in this context. Since taurine is already being used clinically, we considered that its clinical application would also likely be smooth.

Objective: This study aimed to use quantitative values, calculated from bone single photon emission computed tomography (SPECT) imaging, to estimate the reliability of progression evaluation for anti-resorptive agent-related osteonecrosis of the jaw (ARONJ)., Methods: The study population consisted of 21 patients (23 lesions), clinically diagnosed with mandibular ARONJ, who underwent SPECT/CT scanning. Diagnosis and staging of ARONJ were performed according to the American Association of Oral and Maxillofacial Surgeons (AAOMS) definition and the recommendations of the International Task Force on ONJ. Hybrid SPECT/CT imaging quantitative analyses were performed on a workstation. Each volume of interest (VOI) was semi-automatically placed over a lesion with areas of high tracer accumulation, using the GI-BONE ® software default threshold method settings. Additionally, control VOI was manually set over an unaffected area. Measured parameters included standardized uptake values (SUV)-maximum (SUV max ) and mean (SUV mean ), metabolic bone volume (MBV)-the total volume above the threshold, and total bone uptake (TBU) as calculated by MBV × SUV mean . We also calculated the SUV ratio (rSUV) between the lesion and control area, factoring for differences in individual bone metabolism; the ratios were termed rSUV max and rSUV mean , accordingly. The product of multiplying the rSUV mean by MBV of a lesion was defined as the ratio of TBU (rTBU). Quantitative values were compared between clinical stages by the Kruskal-Wallis test and subsequent post hoc analysis., Results: MBVs (cm 3 ) were: median, [IQR] Stage 1, 8.28 [5.62-9.49]; Stage 2, 15.28 [10.64-24.78]; and Stage 3, 34.61 [29.50-40.78]. MBV tended to increase with stage increase. Furthermore, only MBV showed a significant difference between clinical stages (p < 0.01). Subsequent post hoc analysis showed no significant difference between stages 1 and 2 (p = 0.12) but a significant difference between stages 2 and 3 (p = 0.048). rSUVmax and rTBU tended to increase with stage increase, but the differences between the stages were not significant (p = 0.10 and p = 0.055, respectively)., Conclusion: MBV, which includes the concept of volume, showed significant differences between clinical stages and tended to increase with the stage increase. As an objective and reliable indicator, MBV might be an adjunct diagnostic method for staging ARONJ.

Objectives: Osteonecrosis of the femoral head (ONFH), largely caused by alcohol abuse, is a refractory bone disease characterized by the impaired capacity of osteogenic differentiation of bone mesenchymal stem cells (BMSCs), as well as the disordered adipocyte accumulation. Chrysophanic acid (CPA) is a natural anthraquinone which has lipid regulation and bone protection capacity. The aim of this study was to reveal the potential function of CPA and the underlying mechanisms for the alcohol-induced ONFH., Materials and Methods: The effects of alcohol and CPA on BMSCs were investigated by cell proliferation, induced differentiation assays and immunofluorescent staining. Meanwhile, the function of PI3K/AKT and AMPK pathway was investigated in the process of osteogenic and adipogenic differentiation, respectively. Furthermore, we established the rat model of alcohol-induced ONFH to reveal the pharmacotherapeutic effect of CPA in vivo using radiographical and histopathological methods., Results: In vitro, alcohol significantly inhibited the proliferation and osteogenic differentiation of BMSCs but stimulated the adipogenic differentiation. However, CPA could counteract the anti-osteogenesis of alcohol partly via PI3K/AKT pathway and retard the promotion of alcohol-induced adipogenesis via AMPK pathway. In vivo, radiographical and histopathological findings showed that CPA could alleviate alcohol-induced ONFH and substantially restore the bone volume., Conclusions: We demonstrated that CPA ameliorated alcohol-induced ONFH possibly via regulating the differentiation tendency of BMSCs. Hence, CPA may become a beneficial herb extract to alleviate alcohol-induced ONFH., (© 2020 The Authors. Cell Proliferation Published by John Wiley & Sons Ltd.)

Context.—: Decisions to perform hip arthroplasty rely on both radiographic and clinical findings. Radiologists estimate degree of osteoarthritis (OA) and document other findings. Arthroplasty specimens are sometimes evaluated by pathology., Objective.—: To determine the frequency of pathologic changes not recognized clinically., Design.—: Nine hundred fifty-three consecutive femoral head resections performed between January 2015 and June 2018, with recent radiologic and histologic study, were reviewed. We compared severity of OA reported by radiology and pathology. Findings unrecognized radiographically but recorded pathologically, and discrepancies between clinical diagnosis and pathology diagnosis, were tabulated., Results.—: Twenty-one cases of osteomyelitis were diagnosed radiographically or pathologically. Eight discrepancies were present. Fourteen osteomyelitis cases were recognized clinically. Pathology recognized 2 neoplasms missed radiographically. Avascular necrosis was diagnosed on pathology but not radiology in 25 cases, and 35 cases of avascular necrosis were seen radiographically but not pathologically. Osteoarthritis was graded both radiographically and pathologically from 0 to 3. Five hundred ninety-one of 953 cases (62%) were grade 3. Pathologists and radiologists had perfect agreement in 696 of 953 cases (73%). When grade of OA seen at pathology was correlated with surgeon, 2 groups of surgeons were detected: one with a low threshold for performance of hip arthroplasty (23%-28% low-severity OA) and the second with a high threshold (2%-5% low-severity OA)., Conclusions.—: Correlation between radiology and pathology diagnoses is high. Degree of OA present varies significantly between surgeons. Pathology discloses findings not recognized clinically.

Background: Femoral head collapse is the key to the progress of osteonecrosis of the femoral head (ONFH), but the causes of collapse are not completely clear. The better understanding of the progress of femoral head collapse will guide the treatment strategy for ONFH patients. The purpose of this study was to evaluate the biomechanical influence of necrosis area on the collapse of the femoral head by finite element analysis., Methods: CT and MRI data from the hip joint of a healthy volunteer were collected to establish a finite element (FE) model of a normal hip. Subsequently, five categories of osteonecrosis FE models were established by using the normal model and computer software according to China-Japan Friendship Hospital (CJFH) classification for ONFH. The CJFH system includes five types based on the size and location of necrosis lesions in the femoral head (type M, C, L1, L2, and L3) and the stage of ONFH. The collapse indices of each model were analyzed by FE method, including the displacement, peak von Mises stress and stress index of the simulated necrotic area as well as the lateral pillar contact area of the femoral head to acetabular., Results: (1) The displacement increments in the simulated necrotic areas of type M, C, L1, L2, and L3 models were 3.75 μm, 8.24 μm, 8.47 μm, 18.42 μm, and 20.44 μm respectively; the peak von Mises stress decrements were 1.50 MPa, 3.74 MPa, 3.73 MPa, 4.91 MPa, and 4.92 MPa respectively; and the stress indices were 0.04, 0.08, 0.08, 0.27, and 0.27 respectively. (2) The displacement increments in the lateral pillar contact areas of five type models were significantly different (P < 0.001) and increased in sequence as follows: 1.93 ± 0.15 μm, 5.74 ± 0.92 μm, 5.84 ± 1.42 μm, 14.50 ± 3.00 μm, and 16.43 ± 3.05 μm. The peak von Mises stress decrements were also significantly different (P < 0.001) and increased in sequence as follows: 0.52 ± 0.30 MPa, 0.55 ± 0.12 MPa, 0.67 ± 0.33 MPa, 4.17 ± 0.59 MPa, and 4.19 ± 0.60 MPa. (3) The collapse indices including the displacement increments and peak von Mises stress decrements of type L2 and L3 models were markedly higher than those of type M, C, and L1 models (P < 0.001)., Conclusions: The collapse indices of the femoral heads of type L2 and L3 FE models were significantly higher than those of type M, C, and L1. Different areas of necrosis result in varied impact on the femoral head collapse.

Characteristic pathological changes in osteonecrosis of the femoral head (ONFH) include reduced osteogenic differentiation of bone mesenchymal stem cells (BMSCs), impaired osseous circulation and increased intramedullary adipocytes deposition. Osthole is a bioactive derivative from coumarin with a wide range of pharmacotherapeutic effects. The aim of this study was to unveil the potential protective role of osthole in alcohol-induced ONFH. In vitro, ethanol (50 mmol/L) remarkably decreased the proliferation and osteogenic differentiation of BMSCs and impaired the proliferation and tube formation capacity of human umbilical vein endothelial cell (HUVECs), whereas it substantially promoted the adipogenic differentiation of BMSCs. However, osthole could reverse the effects of ethanol on osteogenesis via modulating Wnt/β-catenin pathway, stimulate vasculogenesis and counteract adipogenesis. In vivo, the protective role of osthole was confirmed in the well-constructed rat model of ethanol-induced ONFH, demonstrated by a cascade of radiographical and pathological investigations including micro-CT scanning, haematoxylin-eosin staining, TdT-mediated dUTP nick end labelling, immunohistochemical staining and fluorochrome labelling. Taken together, for the first time, osthole was demonstrated to rescue the ethanol-induced ONFH via promoting bone formation, driving vascularization and retarding adipogenesis., (© 2020 The Authors. Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

Recently, the role of microRNAs (miRs) in human diseases has been verified. This study was determined to explore the protective effects of microRNA-26a (miR-26a) in steroid-induced osteonecrosis of the femoral head (SONFH) with the involvement of enhancer of zeste homologue 2 (EZH2).Femoral head (FH) samples from SONFH patients and patients with femoral neck fracture were collected, and rat SONFH models were established by Escherichia coli endotoxin combining with large dose steroid pulse assay. The hemorheology, blood lipid, inflammatory factors, and pathologic changes were measured by a series of experiments. Moreover, the detection of osteoblasts, osteoclasts, miR-26a expression, EZH2 expression, osteoprotegerin (OPG) and osteoprotegerin ligand (OPGL), and the apoptosis of osteocytes were conducted. The target relation between miR-26a and EZH2 was clarified by bioinformatics and dual-luciferase reporter gene assay.MiR-26a was poorly expressed, while EZH2 was highly expressed in SONFH, and the elevation of miR-26a could repress EZH2 expression. Elevated miR-26a and reduced EZH2 were able to decelerate the apoptosis of osteocytes, increase osteoblasts, and decrease osteoclasts, resulting in a repression of SONFH progression. Additionally, EZH2 was a target gene of miR-26a. Furthermore, the elevation of EZH2 could reverse the repression of SONFH progression that is induced by elevated miR-26a.We found that up-regulation of miR-26a and knockdown of EZH2 could suppress the development of SONFH, which would contribute to the therapy of SONFH.

Aseptic loosening caused by wear particles is a common complication after total hip arthroplasty. We investigated the effect of the quercetin on wear particle-mediated macrophage polarization, inflammatory response and osteolysis. In vitro, we verified that Ti particles promoted the differentiation of RAW264.7 cells into M1 macrophages through p-38α/β signalling pathway by using flow cytometry, immunofluorescence assay and small interfering p-38α/β RNA. We used enzyme-linked immunosorbent assays to confirm that the protein expression of M1 macrophages increased in the presence of Ti particles and that these pro-inflammatory factors further regulated the imbalance of OPG/RANKL and promoted the differentiation of osteoclasts. However, this could be suppressed, and the protein expression of M2 macrophages was increased by the presence of the quercetin. In vivo, we revealed similar results in the mouse skull by μ-CT, H&E staining, immunohistochemistry and immunofluorescence assay. We obtained samples from patients with osteolytic tissue. Immunofluorescence analysis indicated that most of the macrophages surrounding the wear particles were M1 macrophages and that pro-inflammatory factors were released. Titanium particle-mediated M1 macrophage polarization, which caused the release of pro-inflammatory factors through the p-38α/β signalling pathway, regulated OPG/RANKL balance. Macrophage polarization is expected to become a new clinical drug therapeutic target., (© 2020 The Authors. Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

Rationale: Shoulder pain is a common complaint among patients, and rotator cuff disorders are the most common diagnoses. Humeral head osteonecrosis is easily masked by other more common diagnoses and concomitant conditions., Patient Concerns: This challenging diagnostic report consists of 2 cases. Case 1 was that of a 59-year-old man who presented with right shoulder pain that had lasted for >1 year. Case 2 was that of a 52-year-old man who complained of right shoulder pain lasting for 6 months. They both presented with chronic right shoulder pain without relevant trauma history, and the physical examination showed a tenderness point over the right greater tuberosity., Diagnosis: These 2 patients were diagnosed with osteonecrosis involving the right greater tuberosity region via magnetic resonance imaging., Interventions: In case 1, the patient underwent cord decompression and artificial bone grafting with C-arm guidance. In case 2, the patient refused surgical intervention and decided to continue receiving physical therapy for symptom control., Outcomes: In case 1, the patient responded well to cord decompression and artificial bone grafting. After the surgery, the active range of motion was restored and the pain in the right shoulder diminished further. In case 2, conservative treatment helped alleviate the patient's shoulder pain but did not entirely eliminate it., Lessons: Physicians should always have a high index of suspicion for osteonecrosis, especially when treating chronic shoulder pain, regardless of whether there are typical symptoms/known risk factors or not.

Bone diseases represent an increasing health burden worldwide, and basic research remains necessary to better understand the complexity of these pathologies and to improve and expand existing prevention and treatment approaches. In the present study, 216 bone samples from the caput femoris and collum femoris of 108 patients with degenerative or dysplastic coxarthrosis, hip fracture, or osteonecrosis were evaluated for the proportion of trabecular bone (TB) and expression of parathyroid hormone (PTH) type 1 receptor (PTH1R), osteoprotegerin (OPG), and receptor activator of nuclear factor kappa-B ligand (RANKL). Serum levels of PTH, OPG, soluble RANKL (sRANKL), alkaline phosphatase (AP), osteocalcin, total procollagen type-1 intact N-terminal propeptide (TP1NP), tartrate-resistant acid phosphatase type 5b (TRAP5b), sclerostin, and C-telopeptide of type-1 collagen (ICTP) were also determined. Age was positively correlated with serum levels of PTH, OPG, and sclerostin but negatively associated with TB and sRANKL. Women exhibited less TB, lower sclerostin and ICTP, and higher TRAP5b. Impaired kidney function was associated with shorter bone decalcification time, less TB, lower sRANKL, and higher serum PTH, OPG, and sclerostin. Furthermore, correlations were observed between bone PTH1R and OPG expression and between serum PTH, OPG, and AP. There were also positive correlations between serum OPG and TP1NP; serum OPG and sclerostin; serum AP, osteocalcin, and TRAP5b; and serum sclerostin and ICTP. Serum OPG was negatively associated with sRANKL. In summary, clear relationships between specific bone metabolism markers were observed, and distinct influences of age, sex, and kidney function, thus underscoring their suitability as diagnostic or prognostic markers., Competing Interests: The authors have declared that no competing interests exist.

Steroid-induced osteonecrosis of the femoral head (ONFH) is a severe orthopedic disease caused by the long-term administration of glucocorticoids. The main pathological feature of ONFH is the gradually progressive necrosis of bone cells and the bone marrow, ultimately resulting in structural changes or even complete collapse of the femoral head. However, the exact pathogenic mechanism of ONFH remains unknown. Noncoding RNAs (ncRNAs) have emerged as very powerful regulators of gene expression, functioning at both transcriptional and posttranscriptional levels in the pathogenesis of ONFH. Here, we review the current knowledge of the role of ncRNAs, including microRNAs, long noncoding RNAs, and circular RNAs, in the pathogenesis of steroid-induced ONFH. Further focus and validation of these associations can provide new insight into the pathogenic mechanisms at the molecular level to suggest targets for treatment and prevention., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2019 Xinjie Wu et al.)

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., Competing Interests: The authors declare they have no competing interests., (Copyright © 2019 Zhongxin Zhu et al.)

Aim: To evaluate top-ranking genes identified through genome-wide association studies for an association with corticosteroid-related osteonecrosis in children with acute lymphoblastic leukemia (ALL) who received Dana-Farber Cancer Institute treatment protocols. Patients & methods: Lead SNPs from these studies, as well as other variants in the same genes, pooled from whole exome sequencing data, were analyzed for an association with osteonecrosis in childhood ALL patients from Quebec cohort. Top-ranking variants were verified in the replication patient group. Results: The analyses of variants in the ACP1-SH3YL1 locus derived from whole exome sequencing data showed an association of several correlated SNPs (rs11553746, rs2290911, rs7595075, rs2306060 and rs79716074). The rs79716074 defines *B haplotype of the APC1 gene, which is well known for its functional role. Conclusion: This study confirms implication of the ACP1 gene in the treatment-related osteonecrosis in childhood ALL and identifies novel, potentially causal variant of this complication.

Bone marrow mesenchymal stem cells (BMSCs) play an important role in the process of bone repair. The present study investigated the effect of 5-azacytidine (AZA) and trichostatin A (TSA) on BMSC behaviors in vitro. The role of WNT family member 5A (WNT5A)/WNT family member 5A (WNT7A)/beta-catenin signaling was also investigated. BMSCs were isolated from a steroid-induced avascular necrosis of the femoral head (SANFH) rabbit model. The third-generation of BMSCs was used after identification. The results revealed obvious degeneration and necrosis in the SANFH rabbit model. AZA, TSA and TSA + AZA increased BMSC proliferation in a time-dependent fashion. AZA, TSA and TSA + AZA induced the cell cycle release from the G0/G1 phase and inhibited apoptosis in BMSCs. AZA, TSA and TSA + AZA treatment significantly decreased caspase-3 and caspase-9 activities. The treatment obviously increased the activity and relative mRNA expression of alkaline phosphatase. The treatment also significantly up-regulated the proteins associated with osteogenic differentiation, including osteocalcin and runt-related transcription factor 2 (RUNX2), and Wnt/beta-catenin signal transduction pathway-related proteins beta-catenin, WNT5A and WNT7A. The relative levels of Dickkopf-related protein 1 (an inhibitor of the canonical Wnt pathway) decreased remarkably. Notably, TSA + AZA treatment exhibited a stronger adjustment ability than either single treatment. Collectively, the present studies suggest that AZA, TSA and TSA + AZA promote cell proliferation and osteogenic differentiation in BMSCs, and these effects are potentially achieved via upregulation of WNT5A/WNT7A/b-catenin signaling.

Background: Familial digital arthropathy-brachydactyly (FDAB) and Thiemann disease are non-inflammatory digital arthropathies with many phenotypic similarities. Thirty-three cases of Thiemann disease have been described so far (Mangat et al, Ann Rheum Dis 64:11-2, 2005; Ha et al, Thiemann's disease: a case Report, 2017) but no gene variants have been identified as causative to date. FDAB is reported in only a few patients and has been associated with three heterozygous missense variants in the Transient receptor potential vanilloid 4 (TRPV4) gene. We report a TRPV4 variant in a father and son referred with a diagnosis of Thiemann disease and compare the clinical and radiological features of Thiemann disease with Familial digital arthropathy-brachydactyly (FDAB). We hypothesize that these two entities may be one and the same., Methods: We describe a father and son referred with a diagnosis of Thiemann disease who were subsequently identified with a heterozygous variant (c.809G > T) in TRPV4. The identical genetic variant was previously reported to cause FDAB. A PUBMED® database search was conducted to retrieve articles related to Thiemann disease and FDAB. We were able to review the clinical and radiological findings of nineteen individuals affected by Thiemann disease and compare them with three families affected by FDAB., Results: Thiemann disease initially affects the proximal interphalangeal joints and primarily the middle phalangeal bases. In FDAB, the distal phalangeal joints are first affected with the middle phalangeal heads being the primary site of changes. Radial deviation has only been described in FDAB. Our analysis determined that 5 of 20 individuals affected by Thiemann disease have clinical and radiological findings that also fit well with FDAB., Conclusion: FDAB and Thiemann disease are non-inflammatory digital arthropathies with phenotypic overlap. Although more extensive joint involvement, a distal hand joint preponderance and brachydactyly are expected in FDAB, there are striking clinical and radiological similarities between the two entities. Our analysis suggests that these two phenotypes may represent phenotypic variability of the same entity. Despite many attempts to identify other reported patients affected by Thiemann disease, we were not able to procure DNA from any of the cases to verify our findings. Genetic testing of an affected individual will be crucial in order to provide accurate reproductive genetic counselling about the autosomal dominant nature of this condition.

The dysregulated expression of LSINCT5 (long stress-induced non-coding transcript 5) has been found in various human tumors, and was generally related to cancer progression and unfavorable prognosis. Although the role of LSINCT5 in osteosarcoma was reported not long ago, the sample size of that study was limited. Our study presented more evidence about the clinical significance and biological function of LSINCT5 in osteosarcoma. In our results, we found LSINCT5 expression was increased in osteosarcoma tissue samples and cell lines, and high LSINCT5 expression was associated with advanced Enneking stage, large tumor size, high histological grade and present distant metastasis. Meanwhile, we observed high LSINCT5 expression was correlated with worse overall survival, and high LSINCT5 expression could be an independent poor predictor for overall survival in osteosarcoma cases. Moreover, we found inhibition of LSINCT5 expression suppressed cell proliferation, migration and invasion in vitro , and LSINCT5 overexpression dramatically facilitated cell proliferation, migration and invasion in vitro In conclusion, our study suggests that LSINCT5 exerts oncogenic function in osteosarcoma cells, and may be a potential predictor for clinical outcome in osteosarcoma patients., (© 2019 The Author(s).)

Background: Microvascular problems like increased intraosseous pressure or venous congestion may influence the development of Kienböck's disease. We examined if wrist position modifies the blood flow in the nutrient vessels., Methods: Retrospective analysis of 17 patients with Kienböck's disease who had a superselective microangiography of the radial, ulnar and interosseous artery in different wrist positions under general anaesthesia. We analysed the data with Fisher's exact and Wilcoxon-test., Results: We found vessels that entered the bone, that ended at the bone edge, and that supplied a vascular plexus. The origins were the anterior interosseous artery in 10 of 17 cases, the radial artery in seven cases, and the ulnar artery in five cases. Movement of the wrist could reduce or stop the blood flow. Type of lunate configuration showed no significant influence on the blood supply in neutral position., Conclusion: The radial, ulnar, and anterior interosseous artery contribute to the vascular supply of the lunate bone in different combinations. Wrist movement can reduce blood flow to the lunate bone.

The association of the high blood pressure D variant of the angiotensin-converting enzyme (ACE) gene with medication-related jaw osteonecrosis (MRONJ) is described in two Greek patients. The first patient, a 73-year-old man, took zolendronate, 4 mg/100 ml IV once per month for two years for prostate cancer and bone metastases. Three months after drug discontinuation, extraction of the first premolar was performed. After the intervention, he suffered from osteonecrosis of the mandible. He presented with hypertension and genetic testing revealed that he was homozygous for the high blood pressure D variant of the ACE gene. The second patient, a 65 years old woman, took denosumab, 120 mg subcutaneously once per month for 6 months for possible bone metastases from breast cancer. Three months after extraction of the first molar, she suffered from MRONJ. He also presented with hypertension and genetic testing revealed that she had the high blood pressure D variant of the ACE gene in a heterozygous state, which moderately predisposes to hypertension. To our knowledge, this is the first report indicating that genetic predisposition to hypertension may increase risk for MRONJ., (Copyright© 2019, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)