The apoptosis of osteoblasts and osteocytes in femoral head osteonecrosis: its specificity and its distribution

Microstructural and transcriptomic characterization of trabecular bone in idiopathic osteonecrosis of the femoral head

This study aimed to investigate whether idiopathic osteonecrosis of the femoral head (ONFH) is associated with alterations in the microstructure, histological characteristics, and transcriptomic signature in the trabecular region of the femoral head. For this purpose, we obtained trabecular bone explants from the femoral head and the intertrochanteric region of patients with idiopathic ONFH and age- matched patients with primary osteoarthritis (OA). Trabecular bone from the femoral head of ONFH patients showed lower trabecular thickness, bone volume fraction and degree of anisotropy, and a higher percentage of empty lacunae than bone samples from the intertrochanteric region of the same patients and from the femoral head of the OA group. The transcriptome analysis identified a substantial number of genes exclusively regulated in the femoral head of ONFH patients. Among these genes, we found that those highly expressed around the necrotic lesion were involved in cell division and immune response. By contrast, downregulated genes were mainly involved in cell adhesion, angiogenesis and bone formation, such as those encoding collagen type I, bone sialoprotein and several bone morphogenetic proteins. These data add new insights into mechanisms involved in the pathophysiology of idiopathic ONFH.

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

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

Zoledronic Acid and Enriched Autologous Bone Marrow Stem Cell Implantation for Femoral Head Osteonecrosis

Purpose

This study evaluated the clinical results of zoledronic acid in the treatment of early osteonecrosis of the femoral head (ONFH).

Materials and Methods

Study retrospectively analyzed 60 patients with zoledronic acid with bone marrow stem cell (BMSC) implantation (The study group) and 64 patients with BMSC implantation (The control group). The primary evaluation index included VAS, HHS, collapsed rate, and total hip replacement arthroplasty (THA) conversion rate.

Results

The study group had a lower VAS (1.12 ± 0.22 vs 1.44 ± 0.32) and higher HHS (75.07 ± 3.66 vs 68.78 ± 2.24) compared to the control group in 6 months after surgery (P < 0.05). In the study group, 12 hips (20%) collapsed, and 7 of 60 hips (11.67%) required THA surgery at the last follow-up. However, 25 hips (38.8%) collapsed in the control group, and 19 hips (29.69%) required THA surgery. The study group had a lower collapsed rate (P = 0.029) and THA conversion rate (P = 0.016) in survival analysis.

Conclusion

Zoledronic acid and BMSC implantation in the treatment of early ONFH is safe and effective, reduces pain shortens recovery time, and reduces collapsed rate and THA conversion rate in ONFH patients.

TRIM21 silencing inhibits the apoptosis and expedites the osteogenic differentiation of dexamethasone‑induced MC3T3‑E1 cells by activating the Keap1/Nrf2 pathway

Steroid-induced osteonecrosis of the femoral head (ONFH) is a serious complication caused by long-term or excessive use of glucocorticoids. The present study aimed to ascertain the effects of tripartite motif-containing protein 21 (TRIM21) on the process of steroid-induced ONFH and its hidden action mechanism. TRIM21 expression in dexamethasone (Dex)-treated mouse MC3T3-E1 preosteoblast cells was examined using reverse transcription-quantitative PCR and western blotting. The Cell Counting Kit-8 (CCK-8) method and lactate dehydrogenase release assay were used to respectively measure cell viability and injury. Flow cytometry analysis was used to assay cell apoptosis. Caspase 3 activity was evaluated using a specific assay, while alkaline phosphatase and Alizarin red S staining were used to evaluate osteogenesis. 2,7-dichloro-dihydrofluorescein diacetate fluorescence probe was used to estimate reactive oxygen species generation. Specific assay kits were used to appraise oxidative stress levels. In addition, the expression of apoptosis-, osteogenic differentiation- and Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2) signaling-associated proteins was assessed using western blotting. In Nrf2 inhibitor (ML385)-pretreated MC3T3-E1 cells exposed to Dex, cell apoptosis, osteogenesis and oxidative stress were detected again as aforementioned. Results revealed that TRIM21 expression was raised in Dex-induced MC3T3-E1 cells and TRIM21 deletion improved the viability and osteogenic differentiation, whereas it hampered the oxidative stress and apoptosis in MC3T3-E1 cells with Dex induction. In addition, silencing of TRIM21 activated Keap1/Nrf2 signaling. Moreover, ML385 partially abrogated the effects of TRIM21 depletion on the oxidative stress, apoptosis and osteogenic differentiation in MC3T3-E1 cells exposed to Dex. In conclusion, TRIM21 silencing might activate Keap1/Nrf2 signaling to protect against steroid-induced ONFH.

Knowledge mapping of programmed cell death in osteonecrosis of femoral head: a bibliometric analysis (2000-2022)

BACKGROUND

Osteonecrosis of the femoral head (ONFH) is a common, refractory and disabling disease of orthopedic department, which is one of the common causes of hip pain and dysfunction. Recent studies have shown that much progress has been made in the research of programmed cell death (PCD) in ONFH. However, there is no bibliometric analysis in this research field. This study aims to provide a comprehensive overview of the knowledge structure and research hot spots of PCD in ONFH through bibliometrics.

METHOD

The literature search related to ONFH and PCD was conducted on the Web of Science Core Collection (WoSCC) database from 2002 to 2021. The VOSviewers, "bibliometrix" R package and CiteSpace were used to conduct this bibliometric analysis.

RESULTS

In total, 346 articles from 27 countries led by China and USA and Japan were included. The number of publications related to PCD in ONFH is increasing year by year. Shanghai Jiao Tong University, Xi An Jiao Tong University, Wuhan University and Huazhong University of Science and Technology are the main research institutions. Molecular Medicine Reports is the most popular journal in the field of PCD in ONFH, and Clinical Orthopaedics and Related Research is the most cocited journal. These publications come from 1882 authors among which Peng Hao, Sun Wei, Zhang Chang-Qing, Zhang Jian and Wang Kun-zheng had published the most papers and Ronald S Weinstein was cocited most often. Apoptosis, osteonecrosis, osteonecrosis of the femoral head, glucocorticoid and femoral head appeared are the main topics the field of PCD in ONFH. Autophagy was most likely to be the current research hot spot for PCD in ONFH.

CONCLUSION

This is the first bibliometric study that comprehensively summarizes the research trends and developments of PCD in ONFH. This information identified recent research frontiers and hot directions, which will provide a reference for scholars studying PCD in ONFH.

Injectable heat-sensitive nanocomposite hydrogel for regulating gene expression in the treatment of alcohol-induced osteonecrosis of the femoral head

For repairing lesions, it is important to recover physiological and cellular activities. Gene therapy can restore these activities by regulating the expression of genes in lesion cells; however, in chronic diseases, such as alcohol-induced osteonecrosis of the femoral head (ONFH), gene therapy has failed to provide long-term effects. In this study, we developed a heat-sensitive nanocomposite hydrogel system with a secondary nanostructure that can regulate gene expression and achieve long-term gene regulation in lesion cells. This nanocomposite hydrogel exists in a liquid state at 25 °C and is injectable. Once injected into the body, the hydrogel can undergo solidification induced by body heat, thereby gaining the ability to be retained in the body for a prolonged time period. With the gradual degradation of the hydrogel in vivo, the internal secondary nanostructures are continuously released. These nanoparticles carry plasmids and siRNA into lesion stem cells to promote the expression of B-cell lymphoma 2 (inhibiting the apoptosis of stem cells) and inhibit the secretion of peroxisome proliferators-activated receptors γ (PPARγ, inhibiting the adipogenic differentiation of stem cells). Finally, the physiological activity of the stem cells in the ONFH area was restored and ONFH repair was promoted. In vivo experiments demonstrated that this nanocomposite hydrogel can be indwelled for a long time, thereby providing long-term treatment effects. As a result, bone reconstruction occurs in the ONFH area, thus enabling the treatment of alcohol-induced ONFH. Our nanocomposite hydrogel provides a novel treatment option for alcohol-related diseases and may serve as a useful biomaterial for other gene therapy applications.

Serum β-catenin changes vary among different stages of osteonecrosis of the femoral head: an exploratory biomarker study

BACKGROUND

Wnt/β-catenin signaling pathway is closely related to the pathogenesis Osteonecrosis of the femoral head (ONFH). β-catenin, as a major component of Wnt signaling pathway, plays a vital role in the proliferation of osteoblasts. But the effect of altering β-catenin level on the early diagnosis and staging of ONFH has not been studied. Our purpose is to investigate the role of β-catenin level in the progress of ONFH.

METHOD

One hundred and one patients with three stages of ONFH and fifty healthy controls were recruited between May 2016 and November 2016. We divided the patients into 32 cases of stage II, 41 cases of stage III and 28 cases of stage IV according to the Association Research Circulation Osseous (ARCO) classification. We evaluated the clinical bone histomorphology, expression position and level of β-catenin as well as the plasma β-catenin level. We investigated the level of β-catenin from the serum and tissue samples using ELISA and Western Blot assay. We also evaluated the expression of β-catenin in bone tissue by immunohistochemistry. Data were analyzed by independent t-test and ANOVA.

RESULTS

We found that the mean (± SD) serum level of β-catenin was 66.99 ± 3.032 ng/ml in the ONFH patients, which was higher than 20.14 ± 1.715 ng/ml observed in the control group (P < 0.001). Moreover, the β-catenin levels were 49.30 ± 4.649 ng/ml, 72.54 ± 4.864 ng/ml and 79.10 ± 4.773 ng/ml in the ONFH patients with ARCO stage II, stage III and stage IV respectively, showing significant difference among them (P < 0.001). We also found that the area under the curve (AUC) calculated by ROC curve analysis to determine the values for β-catenin levels in ONFH compared with those in the control group was 0.9358 (P < 0.001), where the sensitivity was 77.23% and specificity was 98.00%.

CONCLUSION

Our results indicate that the increased β-catenin may play a vital role in the progress of ONFH and the level of β-catenin is correlated with ARCO stages. The cut-off concentration may be used as one of the sensitive marks to assess the disease process of ONFH.

Revision indications for medial unicompartmental knee arthroplasty: a systematic review

INTRODUCTION

Unicompartmental knee arthroplasty (UKA) has advantages over total knee arthroplasty including fewer complications and faster recovery; however, UKAs also have higher revision rates. Understanding reasons for UKA failure may, therefore, allow for optimized clinical outcomes. We aimed to identify failure modes for medial UKAs, and to examine differences by implant bearing, cement use and time.

MATERIALS AND METHODS

A systematic review was conducted by searching MedLine, EMBASE, CINAHL and Cochrane databases from 2000 to 2020. Studies were selected if they included ≥ 250 participants, ≥ 10 failures and reported all failure modes of medial UKA performed for osteoarthritis (OA).

RESULTS

A total of 24 cohort and 2 registry-based studies (levels II and III) were selected. The most common failure modes were aseptic loosening (24%) and OA progression (30%). Earliest failures (< 6 months) were due to infection (40%), bearing dislocation (20%), and fracture (20%); mid-term failures (> 2 years to 5 years) were due to OA progression (33%), aseptic loosening (17%) and pain (21%); and late-term (> 10 years) failures were mostly due to OA progression (56%). Rates of failure from wear were higher with fixed-bearing prostheses (5% cf. 0.3%), whereas rates of bearing dislocations were higher with mobile-bearing prostheses (14% cf. 0%). With cemented components, there was a high rate of failure due to aseptic loosening (27%), which was reduced with uncemented components (4%).

CONCLUSIONS

UKA failure modes differ depending on implant design, cement use and time from surgery. There should be careful consideration of implant options and patient selection for UKA.

Osteonecrosis in systemic lupus erythematosus: Systematic insight from the epidemiology, pathogenesis, diagnosis and management

Osteonecrosis (ON) is one of the serious and well recognized complicationscausing severe pain and disability in patients with systemic lupus erythematosus (SLE), and its manifestation and pathogenesis are only partially understood. This review provide an update of the recent progress in etiology, pathogenesis, diagnosis, and treatment of systemic lupus erythematosus related osteonecrosis (SLE-ON). Despite the concomitant use of corticosteroids, alcohol and obesity, the dysregulated immune micro-environment and the complex pathogenesis of SLE synergistically play important roles in the development of ON. Osteonecrosis of femoral head (ONFH) is the most often involved joint in SLE. The current classification and staging system of ONFH is based on imaging techniques, particularly relating to MRI and CT, for the identification and quantification of necrotic lesions. For SLE-ONFH patients, both SLE specific clinical symptoms and ONFH imaging findings should be comprehensively evaluated. Even though advances concerning bone grafting and arthroplasty procedures have resulted in improved clinical outcomes, early pharmacological treatment at the pre-collapse stage may prevent joint collapse and reduce the joint arthroplasty rate, and this needs to be accounted. Although some progress has been made, considerably more research is needed before we fully understand SLE-ONFH. Future treatments of SLE-ONFH may involve genetic or cell-based therapies that target potential biomarkers, and this will lead to effective measures for saving thefunction of hip joint and preventing osteonecrosis.

Overexpression of HIF-1α enhances the protective effect of mitophagy on steroid-induced osteocytes apoptosis

Glucocorticoid (GC; dexamethasone, DEX) -induced osteonecrosis of the femoral head (GIOFH) is a challenging orthopedic disease, and its underlying mechanism remains not clear. This study exposed murine long bone osteocyte-Y4 (MLO-Y4) cells to DEX below normoxic or hypoxic circumstances and found that cell autophagy have been reduced. At the same time, flow cytometry analysis showed increased apoptosis, which was more pronounced in hypoxic environments. Recent research also claimed that GC induces osteoporosis after osteocyte apoptosis, and subsequent microfractures lead to ischemia and hypoxia of the femoral head, resulted in GIOFH. Presently, we found that both mitophagy-related protein hypoxia-inducible factor-1α (HIF-1α) and BNIP3 were up-regulated in the hypoxic environment, and their expression was down-regulated when exposed to DEX. Besides, we demonstrated that overexpressing HIF-1α resisted DEX-induced apoptosis in a hypoxic environment. Here, we demonstrated that overexpression of HIF-1α, through its downstream marker BNIP3, reduced the suppression of DEX on mitophagy induced by hypoxia and protected bone cells from apoptosis. Also, these findings may provide a direction of the promising application for better GIOFH treatment shortly.

Glucocorticoid-induced osteonecrosis in systemic lupus erythematosus patients

Osteonecrosis (ON) is a complex and multifactorial complication of systemic lupus erythematosus (SLE). ON is a devastating condition that causes severe pain and compromises the quality of life. The prevalence of ON in SLE patients is variable, ranging from 1.7% to 52%. However, the pathophysiology and risk factors for ON in patients with SLE have not yet been fully determined. Several mechanisms for SLE patients' propensity to develop ON have been proposed. Glucocorticoid is a widely used therapeutic option for SLE patients and high-dose glucocorticoid therapy in SLE patients is strongly associated with the development of ON. Although the hips and knees are the most commonly affected areas, it may be present at multiple anatomical locations. Clinically, ON often remains undetected until patients feel discomfort and pain at specific sites at which point the process of bone death is already advanced. However, strategies for prevention and options for treatment are limited. Here, we review the epidemiology, risk factors, diagnosis, and treatment options for glucocorticoid-induced ON, with a specific focus on patients with SLE.

Osteoblast function in patients with idiopathic osteonecrosis of the femoral head : implications for a possible novel therapy

Aims

To investigate whether idiopathic osteonecrosis of the femoral head (ONFH) is related to impaired osteoblast activities.

Methods

We cultured osteoblasts isolated from trabecular bone explants taken from the femoral head and the intertrochanteric region of patients with idiopathic ONFH, or from the intertrochanteric region of patients with osteoarthritis (OA), and compared their viability, mineralization capacity, and secretion of paracrine factors.

Results

Osteoblasts from the intertrochanteric region of patients with ONFH showed lower alkaline phosphatase (ALP) activity and mineralization capacity than osteoblasts from the same skeletal site in age-matched patients with OA, as well as lower messenger RNA (mRNA) levels of genes encoding osteocalcin and bone sialoprotein and higher osteopontin expression. In addition, osteoblasts from patients with ONFH secreted lower osteoprotegerin (OPG) levels than those from patients with OA, resulting in a higher receptor activator of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) ligand (RANKL)-to-OPG ratio. In patients with ONFH, osteoblasts from the femoral head showed reduced viability and mineralized nodule formation compared with osteoblasts from the intertrochanteric region. Notably, the secretion of the pro-resorptive factors interleukin-6 and prostaglandin E₂ as well as the RANKL-to-OPG ratio were markedly higher in osteoblast cultures from the femoral head than in those from the intertrochanteric region.

Conclusion

Idiopathic ONFH is associated with a reduced mineralization capacity of osteoblasts and increased secretion of pro-resorptive factors.

Cite this article: Bone Joint Res 2021;10(9):619–628.

LRRC17 regulates the bone metabolism of human bone marrow mesenchymal stem cells from patients with idiopathic necrosis of femoral head through Wnt signaling pathways: A preliminary report

Idiopathic necrosis of the femoral head (INFH) is a common disease with unknown cause. Its successful treatment relies on the repair of the necrotic bone. The application of autologous mesenchymal stem cells (MSCs) has shown great promise in saving the patients from undergoing total hip arthroplasty. Leucine-rich repeat-containing 17 (LRRC17) is less expressed in patients with femoral head necrosis and LRRC17 can inhibit bone degradation. However, it remains unknown whether LRRC17 plays a role in the pathogenesis of INFH. The present study aimed to investigate the potential role and mechanism of LRRC17 in the pathogenesis and treatment of INFH. It was found that despite the similar cell morphology and MSC surface marker expressions of human bone marrow MSCs (BMSCs) isolated from patients with INFH (INFH-hBMSC) and femoral neck fracture (FNF) (FNF-hBMSC), INFH-hBMSC had higher percentage of apoptosis (P<0.05), as well as lower osteogenic potential and higher adipogenic potential (both P<0.05). However, there was no difference in cell proliferation between FNF-hBMSC and INFH-hBMSC (P>0.05). It was also confirmed that the expression of LRRC17 was lower in the bone tissue and hBMSCs from patients with INFH compared with patients with FNF (P<0.05). Overexpression of LRRC17 promoted osteogenesis and inhibited the adipogenesis in hBMSCs, accompanied with the increase of Wnt3a and β-catenin expressions, and the decrease of Wnt5a and receptor activator of nuclear factor κ-B ligand (Rankl) expressions (all, P<0.05). Furthermore, knockout of LRRC17 in hBMSCs inhibited the expression levels of osteogenic and promoted adipogenic markers, while decreasing Wnt3a and β-catenin expressions, and increasing Wnt5a and Rankl expressions (all, P<0.05). The present preliminary study suggested that imbalanced bone metabolism may be involved in the pathogenesis of INFH. The modulation of the LRRC17 gene may delay or even restore the balance of osteogenic and adipogenic differentiation in autologous BMSCs derived from patients with INFH, providing a new target for the treatment of INFH.

Necrosis of the femoral head, X-ray microtomography (microCT) and histology of retrieved human femoral heads

Aseptic osteonecrosis of the hip (AON) is a rare, but well-known pathology in rheumatology and orthopedic surgery that is a necrosis of the articular cartilage secondary to a necrosis of the subchondral bone. The microscopic aspect is well known, but the microCT aspect has never been reported or correlated with histopathological findings. The objective of this study was to improve the knowledge of the pathophysiology of AON using histochemistry and microCT. One hundred and sixty femoral heads with stage 3 or 4 AON were analyzed: one half of the head was sent for microCT analysis after impregnation with phosphotungstic acid (PTA) and the other half was used for histological analysis without decalcification. The microCT analysis provides relevant information on the cracked articular cartilage and the relationship with the necrotic subchondral trabecular bone well illustrated on three videos. In histology, Goldner's trichrome showed that the articular cartilage remains well preserved for a long time. In addition, toluidine blue staining reveals a modeling process, i.e. the apposition of new bone without prior resorption by osteoclasts. Rhodamine B staining (fluorescence analysis) reveals that the osteonecrotic trabeculae and subchondral bone were devoid of osteocytes. Areas of peri-necrotic osteosclerosis are due to direct bone formation on the surface of pre-existing necrotic trabeculae.

Early detection of steroid-induced femoral head necrosis using 99mTc-Cys-Annexin V-based apoptosis imaging in a rabbit model

Background

At present, the early diagnosis of femoral head necrosis mainly relies on Magnetic resonance imaging (MRI), and most early patients are difficult to make an accurate diagnosis. Therefore, to investigate the early diagnostic value of ^99mTc-Cys-Annexin V Single-photon emission computed tomography (SPECT) imaging were compared with MRI in rabbit models of steroid-induced femoral head necrosis.

Methods

The animal model of steroid-induced femoral head necrosis (SIFHN) was established in 5-month-old healthy New Zealand white rabbits by injecting horse serum into ear vein and methylprednisolone into gluteal muscle, the purpose of modeling is to simulate the actual clinical situation of SIFNH. ^99mTc-Cys-Annexin V SPECT imaging and MRI were performed at 2nd week, 4th week, and 6th week after modeling. After that, histopathology was used to verify the success of modeling. Apoptosis was detected by transmission electron microscopy (TEM) and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL).

Results

At 2 weeks after the injection of hormone, ^99mTc-Cys-Annexin V SPECT image showed abnormal radioactive uptake in the bilateral femoral head. And over time, the radioactivity concentration was more obvious, and the ratio of T/NT (target tissue/non-target tissues, which is the ratio of femoral head and the ipsilateral femoral shaft) was gradually increased. In the ^99mTc-Cys-Annexin V SPECT imaging at each time point, T/NT ratio of the model group was significantly higher than that of the control group (P < 0.01); at 4 weeks after the injection of hormone, MRI showed an abnormal signal of osteonecrosis. At 2, 4, and 6 weeks after hormone injection, apoptosis was observed by TUNEL and TEM.

Conclusions

^99mTc-Cys-Annexin V SPECT imaging can diagnose steroid-induced femoral head necrosis earlier than MRI, and has potential application value for non-invasively detecting early and even ultra-early stage of femoral head necrosis.

Administration of mircoRNA-135b-reinforced exosomes derived from MSCs ameliorates glucocorticoid-induced osteonecrosis of femoral head (ONFH) in rats

Exosomes were found to exert a therapeutic effect in the treatment of osteonecrosis of the femoral head (ONFH), while miR-135b was shown to play an important role in the development of ONFH. In this study, we investigated the effects of concomitant administration of exosomes and miR-135b on the treatment of ONFH. A rat mode of ONFH was established. TEM, Western blotting and nanoparticle analysis were used to characterize the exosomes collected from human-induced pluripotent stem cell-derived mesenchymal stem cells (hiPS-MSC-Exos). Micro-CT was used to observe the trabecular bone structure of the femoral head. Real-time PCR, Western blot analysis, IHC assay, TUNEL assay, MTT assay and flow cytometry were performed to detect the effect of hiPS-MSC-Exos and miR-135b on cell apoptosis and the expression of PDCD4/caspase-3/OCN. Moreover, computational analysis and luciferase assay were conducted to identify the regulatory relationship between PDCD4 mRNA and miR-135b. The hiPS-MSC-Exos collected in this study displayed a spheroidal morphology with sizes ranging from 20 to 100 nm and a mean concentration of 1 × 1012 particles/mL. During the treatment of ONFH, the administration of hiPS-MSC-Exos and miR-135b alleviated the magnitude of bone loss. Furthermore, the treatment of MG-63 and U-2 cells with hiPS-MSC-Exos and miR-135b could promote cell proliferation and inhibit cell apoptosis. Moreover, PDCD4 mRNA was identified as a virtual target gene of miR-135b. HiPS-MSC-Exos exerted positive effects during the treatment of ONFH, and the administration of miR-135b could reinforce the effect of hiPS-MSC-Exos by inhibiting the expression of PDCD4.

Changes of lipid and bone metabolism in broilers with spontaneous femoral head necrosis

Blood biochemistry and bone metabolism were evaluated to investigate the etiology and mechanism of spontaneous femoral head necrosis (FHN) in broilers. According to the femoral head score of the fourth, fifth, and sixth week old FHN-affected broilers, they were divided into 3 groups, namely Normal group, femoral head separation group, and femoral head separation with growth plate lacerations group, and then carried out a comparative study. The results showed that the liver function (alanine aminotransferase and aspartate aminotransferase) and lipid metabolism (high-density lipoprotein and triglyceride) levels of broilers with spontaneous FHN were significant changed compared with the normal group. At the same time, accumulation of lipid droplets appeared in the liver, which illustrated that the occurrence of FHN may be related to lipid metabolism disorders. Tibia and femur parameters showed significant changes in bone mineral density and bone strength. The distribution of chondrocytes in the articular cartilage of broilers with FHN was irregular and vacuoles appeared, which indicated that cartilage homeostasis was destroyed. TUNEL staining showed that the apoptosis rate of articular chondrocytes in broilers with FHN in 6-week-old was significantly higher than that of normal broilers. Meanwhile, the bone markers (bone glaprotein and bone-specific alkaline phosphatase) changed significantly, indicating that the articular chondrocyte apoptosis and bone metabolism disorder may occur in FHN-affected birds. Therefore, FHN in broilers may be caused by dyslipidemia and abnormal bone metabolism.

cAMP regulates 11β-hydroxysteroid dehydrogenase-2 and Sp1 expression in MLO-Y4/MC3T3-E1 cells

11β-hydroxysteroid dehydrogenase-2 (11β-HSD2) is one of the key enzymes in glucocorticoid metabolism, which can inactivate local corticosterone and regulate the level of active glucocorticoid in tissues. The expression of 11β-HSD2 and its regulatory pathway serve an important role in the apoptosis of steroid induced osteonecrosis of the femoral head (SANFH). The present study aimed to identify the regulatory effects of cAMP on the expression of Sp1 transcription factor (Sp1) and 11β-HSD2 in osteocytes at the cellular level. Murine long bone osteocyte Y4 (MLO-Y4) clone cells and mouse embryo osteoblast-like (MC3T3-E1) cells were cultured in vitro with adenylate cyclase activator or inhibitor (forskolin and SQ22536, respectively) to investigate the effects of alterations to intracellular cAMP levels. mRNA and protein expression levels of Sp1 and 11β-HSD2 were detected by reverse transcription-quantitative PCR and western blotting, respectively. Compared with the negative control group, the mRNA and protein expression levels of Sp1 were significantly increased in the activation group, whereas Sp1 expression levels were significantly decreased in the inhibition group. Similarly, compared with the negative control group, the mRNA and protein expression levels of 11β-HSD2 were significantly increased in the activator group, but significantly decreased in the inhibitor group. The aforementioned results indicated that intracellular cAMP levels significantly regulated the expression of Sp1 and 11β-HSD2 in mouse osteocytes and osteoblasts. Therefore, the present study suggested a potential therapeutic strategy for the prevention of osteonecrosis of the femoral head.

Efficacy of orthobiologic adjuvants to core decompression for hip preservation in avascular necrosis hip

Head preserving modalities in avascular necrosis (AVN) hip are variably effective in early stages, and further options that could prevent head distortion and osteoarthritis are needed. Core decompression (CD) is the most commonly used surgery in the early stages of osteonecrosis with variable rates of success. The present review aimed to determine the effectiveness of bone marrow aspirate concentrate (BMAC), platelet-rich plasma (PRP), bone morphogenetic proteins (BMP) or their combination with CD in early stages of AVN hip, prior to collapse of femoral head. Additionally, any newer unexplored modalities were also searched for and ascertained. PubMed and SCOPUS databases were searched for relevant articles in English language describing CD with aforementioned orthobiologics. We analysed a total of 20 studies published between 2011 and 2020. There were 6 retrospective and 14 prospective studies. PRP showed improved survival and functional outcomes; however, with only three studies, there is inconclusive evidence for its routine utilization. BMAC enhances the efficacy of CD which can further be increased by culture and expansion of cells or combining it with PRP to stimulate growth. In conclusion, CD with BMAC works more efficiently than CD alone prior to collapse of femoral head in AVN. However, PRP needs more evidence for extensive application. Addition of PRP to BMAC or culturing the latter could further enhance the potency of CD + BMAC combination. Very limited data is available for the efficacy of BMP-7 and the role of intraosseous bisphosphonates should be evaluated for a cheaper and potential alternative.

Did Osteoblastic Cell Therapy Improve the Prognosis of Pre-fracture Osteonecrosis of the Femoral Head? A Randomized, Controlled Trial

BACKGROUND

In patients with nontraumatic osteonecrosis of the femoral head (ONFH), implantation of bone marrow aspirate concentrate (BMAC) could delay the progression of osteonecrosis and improve symptoms in pre-fracture ONFH. However, the BMAC content, especially in osteoblastic stem cells, could have an important individual variability. An autologous osteoblastic cell product could improve the effect of such cell-based therapy.

QUESTIONS/PURPOSES

(1) Does autologous osteoblastic cell therapy decrease the likelihood of progression to subchondral fracture with or without early collapse corresponding to Association Research Circulation Osseous (ARCO) classification Stage III or higher, and provide a clinically important pain improvement compared with BMAC treatment alone? (2) Were patients treated with osteoblastic cell therapy less likely to undergo subsequent THA? (3) What proportion of patients in the treatment and control groups experienced adverse events after surgery?

METHODS

Between 2004 and 2011, we treated 279 patients for Stage I to II hip osteonecrosis (ON) with surgery. During that time, our general indications for surgery in this setting included non-fracture ON lesions. To be eligible for this randomized, single-blind trial, patients needed to have an ONFH Stage I or II; we excluded those with traumatic ONFH, hemoglobinopathies and positive serology for hepatitis B, C or HIV. Of those treated surgically for this diagnosis during the study period, 24% (67) agreed to participate in this randomized trial. Hips with pre-fracture ONFH were randomly treated with a core decompression procedure associated with either implantation of a BMAC (BMAC group; n = 26) or osteoblastic cell (osteoblastic cell group; n = 30). The groups were not different in terms of clinical and imaging characteristics. The primary study outcome was treatment response, defined as the absence of progression to subchondral fracture stage (ARCO stage III or higher) plus a clinically important pain improvement defined as 1 cm on a 10-cm VAS. The secondary endpoint of interest was the frequency in each group of subsequent THA and the frequency of adverse events. The follow-up duration was 36 months. We used an as-treated analysis (rather than intention-to-treat) for our efficacy endpoint, and an intention-to-treat analysis for adverse events. Overall, 26 of 26 patients in the BMAC group and 27 of 30 in the osteoblastic cell group completed the trial.

RESULTS

At 36 months, no clinically important differences were found in any study endpoint. There was no difference in the proportion of patients who had progressed to fracture (ARCO stage III or higher; 46% of the BMAC hips [12 of 26] versus 22% in the hips with osteoblastic cells [six of 27], hazard ratio, 0.47 [95% CI 0.17 to 1.31]; p = 0.15). There was no clinically important difference in VAS pain scores. No differences were found for either the WOMAC or the Lequesne indexes. With the numbers available, there was no difference in the proportion of patients in the groups who underwent THA at 36 months 15% (four of 27) with osteoblastic cells versus 35% (nine of 26) with BMAC; p = 0.09 With the numbers available, we found no differences between the treatment and control groups in terms of the frequencies of major adverse events.

CONCLUSIONS

We found no benefit to osteoblastic cells over BMAC in patients with pre-collapse ONFH; side effects were uncommon and generally mild in both groups. This study could be used as pilot data to help determine sample sizes for larger (presumably multicenter) randomized controlled trials. However, this novel treatment cannot be recommended in routine practice until future, larger studies demonstrate efficacy.

LEVEL OF EVIDENCE

Level II, therapeutic study.

Magnetic Targeting of HU-MSCs in the Treatment of Glucocorticoid-Associated Osteonecrosis of the Femoral Head Through Akt/Bcl2/Bad/Caspase-3 Pathway

Purpose

Osteonecrosis of the femoral head (ONFH) is a chronic and irreversible disease that eventually develops into a joint collapse and results in joint dysfunction. Early intervention and treatment are essential for preserving the joints and avoiding hip replacement. In this study, a system of human umbilical mesenchymal stem cells-supermagnetic iron oxide nanoparticles (NPs) @polydopamine (SCIOPs) was constructed. The magnetic targeting system gathers in the lesion area, inhibits the apoptosis of bone cells, enhances osteogenic effect, and effectively treats ONFH under external magnetic field.

Materials and Methods

The supermagnetic iron oxide NPs @polydopamine (SPION@PDA NPs) were characterized by transmission electron microscopy and zeta potential, respectively. The effects of SPION@PDA NPs on the viability, proliferation, and differentiation of stem cells were detected by the CCK8 method, flow cytometry, and staining, respectively. The serum inflammatory indicators were detected by Luminex method. The bone mass of the femoral head was analyzed by micro computed tomography. The expression of apoptosis and osteoblast-related cytokines was detected by Western blotting. The osteogenesis of the femoral head was detected by histological and immunohistochemical sections.

Results

The SCIOPs decreased the pro-inflammatory factors, and the micro CT showed that the bone repair of the femoral head was enhanced after treatment. The hematoxylin and eosin sections also showed an increase in the osteogenesis in the femoral head. Western blotting results showed and increased expression of anti-apoptotic proteins Akt and Bcl-2, decreased expression of apoptotic proteins caspase-3 and Bad, and increased expression of osteogenic proteins Runx-2 and Osterix in the femoral head.

Conclusion

Under the effect of magnetic field and homing ability of stem cells, SCIOPs inhibited the apoptosis of osteoblasts, improved the proliferation ability of osteoblasts, and promoted bone repair in the femoral head through the Akt/Bcl-2/Bad/caspase-3 signaling pathway, thereby optimizing the tissue repair ability.

Correlation between the efficacy of stem cell therapy for osteonecrosis of the femoral head and cell viability

Background

Osteonecrosis of the femoral head (ONFH) is a common disease that greatly affects the quality of life of patients. Repair of the necrotic area is key to successful treatment. Currently, the combination of stem cell transplantation and decompression is used clinically to promote the repair of necrotic areas based on the characteristics of stem cells. However, a considerable number of patients do not achieve a satisfactory outcome in terms of repair of the femoral head necrotic area, and it is very important to determine the reasons for the poor curative effect. The aim of this study was to investigate the correlation between stem cell viability and the repair efficacy of stem cell therapy combined with core decompression for early-stage ONFH.

Methods

A total of 30 patients with idiopathic ONFH underwent core decompression combined with autologous stem cell transplantation. The Harris hip score (HHS) and difference in necrosis area before and after surgery were measured. The mean repair ratio was set as the threshold to divide the patients into group A (ratio above the mean) and group B (ratio below the mean). The ultrastructure, proliferative capacity, and multidirectional differentiation ability were compared between the groups.

Results

At 9 months after surgery, the HHS and magnetic resonance imaging (MRI) findings improved by varying degrees. Based on the mean repair ratio of (62.2 ± 27.0)%, the threshold for dividing the patients into groups A and B was set to 62.2%. Better repair (group A) was associated with more rapid proliferation and a healthier ultrastructure. The cells in group A showed stronger specific staining signifying osteogenic and chondrogenic differentiation; alkaline phosphatase (ALP) activity, an indicator of osteogenic differentiation, was higher in group A than in group B (OD, 2.39 ± 0.44 and 1.85 ± 0.52; p <  0.05).

Conclusions

The quality of implanted stem cells is closely related to treatment efficacy and determines whether the defective self-repair in the necrotic area can be corrected to enhance repair and thus achieve the desired therapeutic outcome.

Trial registration

The trial registration number: ChiCTR-ORC-17011698 (retrospectively registered at 2017-06-19).

Inhibition of PERK Signaling Prevents Against Glucocorticoid-induced Endotheliocyte Apoptosis and Osteonecrosis of the Femoral Head

Vascular injury is considered an important pathological process during glucocorticoid (GC)-induced osteonecrosis of the femoral head (ONFH). In this study, we tried to investigate whether the endoplasmic reticulum (ER) stress is triggered in the GC-induced endotheliocyte (EC) apoptosis and ONFH. The results showed that a GC upregulated the expression of ER stress-related proteins, and PERK-CHOP signaling played an important role and induced EC apoptosis. The inhibition of PERK by GSK2656157 significantly decreased the GC-induced EC apoptosis in vitro and in vivo, thus protecting a rat model from vascular injury and significantly preventing GC-induced ONFH.

Study of Osteocyte Behavior by High-Resolution Intravital Imaging Following Photo-Induced Ischemia

Ischemic injuries and local hypoxia can result in osteocytes dysfunction and play a key role in the pathogenesis of avascular osteonecrosis. Conventional imaging techniques including magnetic resonance imaging (MRI) and computed tomography (CT) can reveal structural and functional changes within bony anatomy; however, characterization of osteocyte behavioral dynamics in the setting of osteonecrosis at the single cell resolution is limited. Here, we demonstrate an optical approach to study real-time osteocyte functions in vivo. Using nicotinamide adenine dinucleotide (NADH) as a biomarker for metabolic dynamics in osteocytes, we showed that NADH level within osteocytes transiently increase significantly after local ischemia through non-invasive photo-induced thrombosis of afferent arterioles followed by a steady decline. Our study presents a non-invasive optical approach to study osteocyte behavior through the modulation of local environmental conditions. Thus it provides a powerful toolkit to study cellular processes involved in bone pathologies in vivo.

Clinical efficiency of bone marrow mesenchymal stem cell implantation for osteonecrosis of the femoral head: a matched pair control study with simple core decompression

Background

To date, several trials have reported the use of mesenchymal stem cell (MSC) implantation for osteonecrosis of the femoral head (ONFH). However, the clinical outcomes have not been conclusive. This study compared the clinical and radiological results of bone marrow mesenchymal stem cell (BMMSC) implantation with traditional simple core decompression (CD) using a matched pair case–control design.

Methods

We retrospectively reviewed 100 patients with ONFH (106 hips) who had been treated by CD alone (50 patients, 53 hips) and CD + BMMSC implantation (50 patients, 53 hips) between February 2004 and October 2014. We assessed the total hip replacement arthroplasty (THA) conversion rate and ARCO (Association Research Circulation Osseous) stage progression. Survivor rate analysis was performed using the Kaplan–Meier method, and an additional THA was defined as the primary endpoints.

Results

The mean follow-up period was 4.28 years. There was a difference in the THA conversion rate between the CD (49%) and CD + BMMSC groups (28.3%) (p = 0.028). ARCO stage progression was noted in 20 of 53 hips (37.7%) in the CD group and 19 of 53 hips (35.8%) in the CD + BMMSC group. Among collapsed cases (ARCO stages III and IV), there was no difference in clinical failure rate between the two groups. Conversely, in the pre-collapse cases (ARCO stages I and II), only 6 of 30 hips (20%) progressed to clinical failure in the CD + BMMSC group, whereas 15 of 30 hips (50%) progressed to clinical failure in the CD group (p = 0.014). Kaplan–Meier survival analysis showed a significant difference in the time to failure between the two groups up to 10-year follow-up (log-rank test p = 0.031). There was no significant difference in terms of age (p = 0.87) and gender (p = 0.51) when comparing THA conversion rates between groups. No complication was noted.

Conclusions

These results suggest that implantation of MSCs into the femoral head at an early stage of ONFH lowers the THA conversion rate. However, ARCO stage progression is not affected by this treatment.

Trial registration

Retrospectively registered

Microbubble-Mediated Ultrasound Outweighs Low-Intensity Pulsed Ultrasound on Osteogenesis and Neovascularization in a Rabbit Model of Steroid-Associated Osteonecrosis

Microbubbles magnify the acoustic pressure of low-intensity pulsed ultrasound (LIPUS) and may enhance its bioeffect for diagnostic and therapeutic purposes. This study compared the effect of this novel microbubble-mediated ultrasound (MUS) with that of the traditional LIPUS on osteogenesis and neovascularization in a rabbit model of steroid-associated osteonecrosis. We hypothesized that MUS might outweigh LIPUS on promoting osteogenesis and neovascularization in steroid-associated osteonecrosis. The bilateral femoral head necrosis was induced by lipopolysaccharide and methylprednisolone in the rabbits. The indices of bone mineral density (BMD), trabecular number, maximal loading strength, and mineral apposition rate were analyzed, demonstrating that the animal model of steroid-associated osteonecrosis was successfully established. Both the MUS group (G_M) and the LIPUS group (G_L) were insonated 20 min daily for six weeks. G_M received an extra intracapsular injection of microbubbles before insonation every other day. Fluorescence bone labeling, Micro-CT Analysis, biomechanical test, quantitative real-time PCR, Western blot analysis, and histological evaluation were performed for comparing G_M with G_L. The results demonstrated a 39% higher mineral apposition rate in G_M compared with G_L. The BMD and the maximal loading strength of femoral head of G_M increased by 4.3% and 27.8% compared to those of G_L, respectively. The mRNA and protein expression of BMP-2 and VEGF were also significantly higher in G_M. The number of blood vessels of G_M was 65% greater than that of G_L. MUS is more potent than LIPUS in enhancing osteogenesis, neovascularization, and biomechanical strength of femoral head in the animal model of steroid-associated osteonecrosis. Without increasing the intensity of insonation or the risk of tissue damage, MUS is better for inhibiting the process of steroid-associated osteonecrosis.

Effects of erythropoietin for precaution of steroid-induced femoral head necrosis in rats

BACKGROUND

Steroids such as glucocorticoid have been widely used for their excellent anti-inflammatory, anti-immune, and anti-shock properties. However, the long-term use in high doses has been found to cause necrosis of femoral head and other serious adverse reactions. Thus, it is of great importance to safely use these medications on patients without inducing bone necrosis.

METHODS

In this preclinical study, we examined the effects of erythropoietin (EPO) to attenuate the induction of steroid-induced femoral bone necrosis using rats to build up the in-vivo models. Rats were randomly divided into three groups: negative control group (group A), disease group (group B), and EPO group (group C). 20 mg/kg methylprednisolone was administrated into group B and group C for 6 weeks with two intramuscular injections per week per rat. Group C was further given daily intraperitoneal injections of rHuEPO during this period. Group A received only injection of saline at the same schedule. 12 weeks after the initial drug administration, the rats' femoral tissues were harvested for HE staining, immunohistochemistry studies for PECAM-1(also CD31) expression and Western Blotting for VEGF expression.

RESULTS

Histology studies showed that compared with the disease group, EPO group had significant improvement and bone morphology being much closer to the negative control group. Immunohistochemical studies revealed that EPO group had statistically much more expression of PECAM-1 than the other groups did. Western Blot demonstrated that the EPO group had significantly higher VEGF expression than the disease group.

CONCLUSION

Results suggested that simultaneous injection of EPO could partially prevent steroid-induced ANFH.

Association of reduced sclerostin expression with collapse process in patients with osteonecrosis of the femoral head

PURPOSE

Sclerostin is an osteocyte-derived protein that has a potent inhibitory effect on osteoblast activity. The osteocyte apoptosis induced by various causes of osteonecrosis of the femoral head (ONFH) plays a key role in the promotion of femoral head collapse. But the effect of altering sclerostin level on the collapse of ONFH has not been studied. Our aim was to assess the role of sclerostin level in the collapse of ONFH.

METHODS

Between May 2016 and November 2016, 236 subjects were enrolled in the present study. The patients were classified according to the Association Research Circulation Osseous (ARCO) classification. The clinical bone histomorphology, the expression position, and level of sclerostin as well as the plasma sclerostin level were evaluated.

RESULTS

The sclerostin level was significantly lower in the non-traumatic ONFH group than those in the healthy control group (P = 0.002). The sclerostin level was negatively associated with ARCO stages (r = - 0.239, P = 0.009) and significantly lower in the postcollapse group (P = 0.025).

CONCLUSIONS

The reduced expression of sclerostin may play a key role in the collapse process of ONFH and be predictive of the disease progression of ONFH.

Lenalidomide regulates osteocytes fate and related osteoclastogenesis via IL-1β/NF-κB/RANKL signaling

Osteolytic diseases are closely associated with osteocyte fate, indicating a more efficient and crucial role of osteocyte-targeting strategy in inhibiting osteoclastogenesis. Here, we investigated the effects of lenalidomide (Lena) on osteocyte fate in order to regulate osteoclastogenesis via effective cascade-controlling response. Our data revealed that lenalidomide treatment notably rescued IL-1β induced loss of osteocyte viability by inhibiting osteocyte apoptosis with decreased osteoclast-related factors, RANKL and Sclerostin, as demonstrated by the restricted osteoclast formation and reduced bone resorption. Additionally, iTRAQ assay revealed that IL-1β induced activation of NF-κB inhibitor α/β were remarkably downregulated by lenalidomide, showing that lenalidomide impaired NF-κB signaling in osteocytes for inhibiting the expression of osteoclast specific genes in osteoclasts, which was further confirmed by KEGG pathway analysis and Western blot. More interestingly, the in vivo analysis of osteocyte apoptosis and osteoclastogenesis in osteoarthritis mice model indicated a role of lenalidomide in the regulation of osteocyte fate and the consequent inhibition of RANKL-induced osteoclastogenesis. Together, these results suggest that lenalidomide regulates osteocyte fate by attenuating IL-1β/NF-κB signaling, thereby inhibiting RANKL expression for the attenuated osteoclastogenesis both in vitro and vivo, indicating a more efficient remedy among future anti-osteoclastogenesis approaches.

Non traumatic osteonecrosis of the femoral head is associated with low bone mass

OBJECTIVE

Osteoporosis (OP) and osteonecrosis of the femoral head (ONFH) share common clinical and pathophysiological features we sought to determine whether ONFH was associated with an increased prevalence of OP and whether the increased prevalence of OP was related to the stage of ONFH at diagnosis.

METHODS

We included 243 patients with ONFH and 399 age and sex-matched healthy controls. Data was gathered including demography, risk factors, ARCO staging of ONFH and bone mineral density (BMD).

RESULTS

Overall, BMD (defined by the T-score) was significantly lower in the ONFH group at both the femoral head (-0.96±1.11) and the lumbar spine (-1.22±1.47) compared to the control group (-0.55±0.97 and -0.73±1.31) (p<0.01). The ONFH group depicted a significantly higher proportion of osteopenia (50.39% vs 40.87%, p=0.027) and of OP (18.78% vs 7.33%, p<0.001) relative to the control group. Stage 1 and 2 ONFH patients (53.86%, p=0.0203; OR=1.54 (95% CI: [1.04; 2.29])) were at a higher risk of osteopenia than the control group (40.88%), but not stages 3 or 4 (48.47%, p=0.2569; OR=1.27 (95% CI: [0.78; 2.06]). Patients with stage 3 or 4 ONFH (25.31%, p<0.001; OR=3.93 (95% CI: [1.63; 10.96])) were at a higher risk of osteoporosis than patients in the stage 1 and 2 ONFH (7.24%), and compared to the control group (7.33%, adj. p-value<0.001; OR=4.89 (95% CI: [2.77; 8.76]).

CONCLUSIONS

Non-traumatic osteonecrosis of the femoral heads is associated with low bone mineral density. This study showed that fractural stages ONFH were associated with a 5-fold risk of osteoporosis.

[The role of glutathione in steroid induced bone marrow mesenchymal stem cells dysfunction]

Objective

To investigate the protective effect of the antioxidant glutathione (GSH) on the steroid-induced imbalance between osteogenesis and adipogenesis in human bone marrow mesenchymal stem cells (BMSCs).

Methods

The BMSCs were isolated from the proximal femur bone marrow from 3 patients of femoral neck fracture and were separated, cultured, and purificated by density gradient centrifugation and adherent wall method in vitro. The third generation BMSCs were divided into 5 groups: group A, BMSCs (1×10 ⁵ cells/mL); group B, BMSCs (1×10 ⁵ cells/mL)+10 μmol/L dexamethasone; group C, BMSCs (1×10 ⁵ cells/mL)+10 μmol/L dexamethasone+5 μmol/L GSH; group D, BMSCs (1×10 ⁵ cells/mL)+10 μmol/L dexamethasone+10 μmol/L GSH; group E, BMSCs (1×10 ⁵ cells/mL)+10 μmol/L dexamethasone+50 μmol/L GSH. After cultured for 7 days, the reactive oxygen species expression was detected by flow cytometry; the superoxide dismutase (SOD) and Catalase mRNA expressions were determined by RT-PCR; the peroxisome proliferator-activated receptors γ (PPAR-γ), CCAAT/enhancer-binding family of proteins (C/EBP), Runx2, and alkaline phosphatase (ALP) mRNA expressions were evaluated by real-time fluorescence quantitative PCR. After cultured for 21 days, Oil red O staining was used to observe the adipogenesis differentiation of cells, and the expressions of related proteins were detected by Western blot.

Results

The reactive oxygen species expression in group B was obviously higher than in the other groups, in group C than in groups A, D, and E, and in groups D, E than in group A, all showing significant differences between groups ( P<0.05); but there was no significant difference between groups D and E ( P>0.05). The oil red O staining positive cells in group B were obviously more than the other groups, and groups C, D, E, and A decreased sequentially, the absorbance ( A) values had significant differences between groups ( P<0.05). RT-PCR detection showed that the relative expressions of SOD and Catalase mRNA in group B were significantly lower than those in the other groups, while in group C than in groups A, D, and E ( P<0.05), but there was no significant difference among groups A, D, and E ( P>0.05). Real-time fluorescence quantitative PCR detection showed that the relative expressions of PPAR-γ and C/EBP mRNA in group B were significantly higher than those in the other groups, while in group C than in groups A, D, and E, and in groups D, E than in group A ( P<0.05); but there was no significant difference between groups D and E ( P>0.05). The relative expressions of Runx2 and ALP mRNA in group B were significantly lower than those in the other groups, while in group C than in groups A, D, and E, and in groups D, E than in group A ( P<0.05); but there was no significant difference between groups D and E ( P>0.05). Western blot detection showed that the relative expression of PPAR-γ and C/EBP protein in group B was significantly higher than those in the other groups, and groups C, D, E, and A decreased sequentially, all showing significant differences between groups ( P<0.05). The relative expression of Runx2 and ALP protein in group B was significantly lower than those in the other groups, and groups C, D, E, and A increased sequentially, all showing significant differences between groups ( P<0.05).

Conclusions

GSH can inhibit the adipogenesis differentiation and enhance the osteogenic differentiation of human BMSCs by reducing the intracellular reactive oxygen species level; and in a certain range, the higher the concentration of GSH, the more obvious the effect is.

Aging and osteoarthritis: Central role of the extracellular matrix

Osteoarthritis (OA), is a major cause of severe joint pain, physical disability and quality of life impairment in the aging population across the developed and developing world. Increased catabolism in the extracellular matrix (ECM) of the articular cartilage is a key factor in the development and progression of OA. The molecular mechanisms leading to an impaired matrix turnover have not been fully clarified, however cellular senescence, increased expression of inflammatory mediators as well as oxidative stress in association with an inherently limited regenerative potential of the tissue, are all important contributors to OA development. All these factors are linked to and tend to be maximized by aging. Nonetheless the role of aging in compromising joint stability and function in OA has not been completely clarified yet. This review will systematically analyze cellular and structural changes taking place in the articular cartilage and bone in the pathogenesis of OA which are linked to aging. A particular emphasis will be placed on age-related changes in the phenotype of the articular chondrocytes.

Inefficacy of autologous bone marrow concentrate in stage three osteonecrosis: a randomized controlled double-blind trial

PURPOSE

The fracture stage of non-traumatic osteonecrosis (ON stage 3) of the femoral head (ONFH) has an unfavourable prognosis frequently requiring total hip replacement (THR). The percentage could be lowered after core decompression. In earlier non-fracture ON stages, implantation of autologous bone marrow aspirate concentrate (BMAC) improved the effect of core decompression. The purpose was to evaluate the effect of BMAC in addition to core decompression in stage 3 ONFH.

METHODS

A double blind RCT was conducted comparing two groups: core decompression plus saline injection or core decompression plus BMAC implantation. Both patients and assessors were blinded to the treatment assignments. Evaluations were done at baseline, three, six, 12, and 24 months, including pain (VAS), WOMAC, side-effects, radiological evolution including ARCO subclassifications, together with possible THR requirement. The primary endpoint was the need for THR. The second endpoints included the clinical symptoms such as pain and functional ability and the progression of the ON lesions as well as the appearance of osteoarthritis features (ARCO stage 4). Both groups included 23 hips (19 patients).

RESULTS

No differences were found between the groups for THR requirements, clinical tests, and radiological evolution. In both groups, 15/23 hips needed THR. The radiological evolution of the ONFH lesions in term of location, extension, surface collapse, and dome depression was moderate in both groups and was not correlated with the need of THR.

CONCLUSIONS

Implantation of BMAC after core decompression did not produce any improvement of the evolution of ONFH stage 3. Level of evidence I.

Association of ABCB1 C3435T polymorphism with the susceptibility to osteonecrosis of the femoral head: A meta-analysis

BACKGROUND AND OBJECTIVE

The exploration for the etiology of osteonecrosis of the femoral head (ONFH) has got some promising findings, but the morbidity of ONFH is still not under control. The C3435T polymorphism of ATP-binding cassette subfamily B member 1 (ABCB1) gene has been reported to possess significant influence on ONFH onset, but relevant outcomes remain conflicting rather than conclusive. Therefore, a meta-analysis was useful to pool these results together for a more reliable conclusion.

METHODS

The association of ABCB1 C3435T polymorphism with ONFH susceptibility was estimated through calculated odds ratios (ORs) with their 95% confidence intervals (95% CIs). The Q-test was applied for detecting inter-study heterogeneity, whereas sensitivity analysis for identifying any study owning substantial influence on pooled results. Begg's funnel plot and Egger's test were employed to examine publication bias across included studies.

RESULTS

ABCB1 C3435T polymorphism significantly decreased the risk of ONFH under TT vs CC (OR = 0.26, 95% CI = 0.13-0.50), TT+CT vs CC (OR = 0.72, 95% CI = 0.52-0.99), TT vs CC+CT (OR = 0.28, 95% CI = 0.15-0.52), and T vs C (OR = 0.64, 95% CI = 0.50-0.81) contrasts.

CONCLUSION

The variant C3435T in the ABCB1 gene may offer protection against the attack of ONFH, and more studies with larger sample sizes should be conducted to certify this issue.

Feasibility and Efficacy of Autologous Bone Marrow Aspirate Transplantation Combined with Human Parathyroid Hormone 1-34 Administration to Treat Osteonecrosis in a Rabbit Model

No studies have examined the transplantation of a bone marrow aspirate (BMA) containing mesenchymal stem cells (MSCs) combined with human parathyroid hormone 1-34 (hPTH1-34) administration. Therefore, we evaluated the feasibility and efficacy of autologous BMA transplantation combined with hPHT1-34 administration in a bone necrosis model. The metatarsal bones of rabbits were necrotized using liquid nitrogen, and the rabbits received a BMA transplantation or saline injection followed by hPTH1-34 (30 μg/kg) or saline administration three times per week (n = 3-4 per group). The rabbits were euthanized at 12 weeks after the initiation of treatment. No systemic adverse effects or local neoplastic lesions were observed. Importantly, the rabbits in the BMA transplantation plus hPTH1-34 group showed the highest bone volumes and histological scores of new bone. These data confirmed the feasibility of BMA transplantation combined with hPTH1-34, at least during the experimental period. The observed efficacy may be explained by a synergistic effect from the stimulation of MSC differentiation to osteoblasts with hPTH1-34-mediated suppression of apoptosis in osteoblasts. These results indicate the promising potential for BMA transplantation combined with hPTH1-34 administration in bone necrosis treatment. Longer term experiments are needed to confirm the safety of this therapeutic strategy.

Region specific Raman spectroscopy analysis of the femoral head reveals that trabecular bone is unlikely to contribute to non-traumatic osteonecrosis

Non-traumatic osteonecrosis (ON) of the femoral head is a common disease affecting a young population as the peak age of diagnosis is in the 40 s. The natural history of non-traumatic ON leads to a collapse of the femoral head requiring prosthetic replacement in a 60% of cases. Although trabecular bone involvement in the collapse is suspected, the underlying modifications induced at a molecular level have not been explored in humans. Here, we examine changes in the molecular composition and structure of bone as evaluated by Raman spectroscopy in human end-stage ON. Comparing samples from femoral heads harvested from 11 patients and 11 cadaveric controls, we show that the mineral and organic chemical composition of trabecular bone in ON is not modified apart from age-related differences. We also show that the molecular composition in the necrotic part of the femoral head is not different from the composition of the remaining ‘healthy’ trabecular bone of the femoral head. These findings support that quality of trabecular bone is not modified during ON despite extensive bone marrow necrosis and osteocyte death observed even in the ‘healthy’ zones on histological examination.

Levodopa attenuates cellular apoptosis in steroid-associated necrosis of the femoral head

The present study aimed to investigate the effects of levodopa (LEV) on cellular apoptosis in a rabbit model of steroid-associated necrosis of the femoral head (SANFH). A total of 44 healthy adult Chinese rabbits were randomly divided into three groups: Group A (n=15), administered a combination of lipopolysaccharide and hormone to establish the SANFH animal model; group B (n=15), SANFH animal model as in group A orally administered LEV (0.4 g/kg/day) on the day of injection; and group C (n=14), the control group. On the 6th and 8th week of modeling, seven rabbits from each group were sacrificed to harvest bilateral femoral head specimens for hematoxylin and eosin staining and apoptosis detection by terminal deoxynucleotidyl transferase dUTP nick-end labeling assay analysis, as well as for observing pathological changes and analyzing cellular apoptosis. Eight weeks after modeling, the serum insulin-like growth factor (IGF)-1 levels of the three groups were measured. The empty lacunae rate and apoptosis index of bone cells in the treatment group were significantly lower than that of the model group (P<0.01). Eight weeks after treatment, the serum levels of IGF-1 were significantly higher than that of the model group (P<0.01). These findings suggested that LEV was able to reduce steroid-induced bone cellular apoptosis, reduce the occurrence of necrosis of the femoral head and, through in vivo metabolism, it may promote the synthesis and release of IGF-1, which could be one of its biological pathways to prevent and treat SANFH.

Differential expression of miR-672-5p and miR-146a-5p in osteoblasts in rats after steroid intervention

BACKGROUND

Apoptosis of osteoblasts and osteocytes is one cause of steroid-induced osteonecrosis of the femoral head; however, the molecular mechanism of steroid affecting osteoblasts at the genetic level is unclear. The aim of the present work is to examine differential expression of osteoblasts in rats after steroid intervention and to verify expression by real-time polymerase chain reaction (RT-PCR).

METHODS

Primary culture, passaging and identification of osteoblasts of SD neonatal rats were conducted; osteoblasts were divided into two groups, the control group, and the steroid group. Total RNA was extracted separately, and quality control was performed; by means of RNA labeling and microarray hybridization, data were collected and then standardized to ascertain differences in miRNA expression between the two groups. The gene expression spectrum was analyzed. Obvious differential expression of miR-672-5p and miR-146a-5p was verified by RT-PCR. Miranda, microcosm and mirdb bioinformatics software were used to predict target genes.

RESULTS

Compared with the control group, morphologically, the osteoblasts in the steroid group were more irregular and showed various shapes. The number of miRNAs (fold change >2) in the steroid group was six. Four miRNAs were upregulated and two miRNAs were downregulated. In particular, upregulated miR-672-5p expression and downregulated miR-146a-5p expression were significant. RT-PCR results showed that the 2(-△△) CT value of miR-672-5p in the steroid group was 3.743-fold of that in the control group, and the 2(-△△) CT value of miR-146a-5p in the steroid group was 0.322-fold of that in the control group. Angptl4, Ccdc51, Ssbp3 and RGD1306991 were predicted as the target gene of miR-672-5p, while Hrp12 was that of miR-146a-5p.

CONCLUSION

Expression profiles of miR-672-5p and miR-146a-5p had the most significant changes in the osteoblasts of rats with steroid intervention, which may provide a new viewpoint to pathogenesis of osteonecrosis of the femoral head.

IL-4 administration exerts preventive effects via suppression of underlying inflammation and TNF-α-induced apoptosis in steroid-induced osteonecrosis

Macrophages play an important role during the development of steroid-induced osteonecrosis. Interleukin (IL)-4 administration helped reduce the infiltration of M1 phenotypic macrophages and maintain the activation of M2 phenotypic macrophages, resulting in restriction of inflammation and decrease in osteocyte apoptosis. The results indicated the therapeutic potential of IL-4 in prevention of steroid-induced osteonecrosis.

INTRODUCTION

Steroid-induced osteonecrosis (ON) is a debilitating disease characterized by the activation and infiltration of macrophages into the necrotic site. This study aimed to investigate the effects of IL-4 administration on macrophage polarization and the involved signaling pathways.

METHODS

Fifty-six BALB/c mice were randomly divided into two groups, group M (model group) and group MI (treatment group), each containing 28 mice. ON model was induced by the injection of methylprednisolone (MPS). The mice in group MI received intra-abdominal injections of 2 μg/100 g/day of rIL-4 for five consecutive days, following the administration of MPS. Osteonecrosis was verified by histopathological staining. The expression of tumor necrosis factor-alpha (TNF-α) was analyzed by ELISA and immunohistochemistry. The infiltration of M1/M2 macrophages was examined by the expression of specific makers of F4/80, CD11c, and CD206 protein. Cell apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay, and the apoptotic signal molecules such as STAT1 and caspase-3 were examined.

RESULTS

Histopathological observations indicated that IL-4 administration reduced the incidence of ON and the accumulation of osteoclasts. IL-4 administration inhibited the expression of TNF-α and reduced the infiltration of M1 phenotypic macrophages and maintained relatively high level of M2 phenotypic macrophages. Additionally, TUNEL assay suggested that IL-4 intervention could reduce the number of apoptotic cells in the necrotic zone. The anti-apoptotic mechanisms were related to STAT1 phosphorylation and the activation of caspase-3.

CONCLUSIONS

Il-4 administration could alleviate steroid associated ON in mice by inhibiting the inflammatory response, the infiltration of M1 phenotypic macrophages, and suppressing TNF-a-induced osteocytic apoptosis by inhibiting the STAT1-caspase-3 signal pathway.

iNOS expression and osteocyte apoptosis in idiopathic, non-traumatic osteonecrosis

BACKGROUND AND PURPOSE

Non-traumatic osteonecrosis is a progressive disease with multiple etiologies. It affects younger individuals more and more, often leading to total hip arthroplasty. We investigated whether there is a correlation between inducible nitric oxide synthase (iNOS) expression and osteocyte apoptosis in non-traumatic osteonecrosis.

PATIENTS AND METHODS

We collected and studied 20 human idiopathic, non-traumatic osteonecrosis femoral heads. Subchondral bone samples in the non-sclerotic region (n = 30), collected from osteoarthritis patients, were used as controls. Spontaneously hypertensive rats were used as a model for osteonecrosis in the study. We used scanning electron microscopy, TUNEL assay, and immunohistochemical staining to study osteocyte changes and apoptosis.

RESULTS

The morphology of osteocytes in the areas close to the necrotic region changed and the number of apoptotic osteocytes increased in comparison with the same region in control groups. The expression of iNOS and cytochrome C in osteocytes increased while Bax expression was not detectable in osteonecrosis samples. Using spontaneously hypertensive rats, we found a positive correlation between iNOS expression and osteocyte apoptosis in the osteonecrotic region. iNOS inhibitor (aminoguanidine) added to the drinking water for 5 weeks reduced the production of iNOS and osteonecrosis compared to a control group without aminoguanidine.

INTERPRETATION

Our findings show that increased iNOS expression can lead to osteocyte apopotosis in idiopathic, non-traumatic osteonecrosis and that an iNOS inhibitor may prevent the progression of the disease.