SpotLink enables sensitive and precise identification of site nonspecific cross-links at the proteome scale.

Nonspecific cross-linker can provide distance restraints between surface residues of any type, which could be used to investigate protein structure construction and protein-protein interaction (PPI). However, the vast number of potential combinations of cross-linked residues or sites obtained with such a cross-linker makes the data challenging to analyze, especially for the proteome-wide applications. Here, we developed SpotLink software for identifying site nonspecific cross-links at the proteome scale. Contributed by the dual pointer dynamic pruning algorithm and the quality control of cross-linking sites, SpotLink identified > 3000 cross-links from human cell samples within a short period of days. We demonstrated that SpotLink outperformed other approaches in terms of sensitivity and precision on the datasets of the simulated succinimidyl 4,4'-azipentanoate dataset and the condensin complexes with known structures. In addition, some valuable PPI were discovered in the datasets of the condensin complexes and the HeLa dataset, indicating the unique identification advantages of site nonspecific cross-linking. These findings reinforce the importance of SpotLink as a fundamental characteristic of site nonspecific cross-linking technologies.

Comprehensive Evaluation and Optimization of the Data-Dependent LC-MS/MS Workflow for Deep Proteome Profiling.

Data-dependent liquid chromatography-tandem mass spectrometry (LC-MS/MS) is widely used in proteomic analyses. A well-performed LC-MS/MS workflow, which involves multiple procedures and interdependent metrics, is a prerequisite for deep proteome profiling. Researchers have previously evaluated LC-MS/MS performance mainly based on the number of identified peptides and proteins. However, this is not a comprehensive approach. This motivates us to develop MSRefine, which aims to evaluate and optimize the performance of the LC-MS/MS workflow for data-dependent acquisition (DDA) proteomics. It extracts 47 kinds of metrics, scores the metrics, and reports visual results, assisting users in evaluating the workflow, locating problems, and providing optimizing strategies. In this study, we compared and analyzed multiple pairs of datasets spanning different samples, methods, and instruments and demonstrated that the comprehensive visual metrics and scores in MSRefine enable us to evaluate the performance of the various experiments and provide optimal strategies for the identification of more peptides and proteins.

miR-126 mitigates the osteogenic differentiation of human bone marrow-derived mesenchymal stem cells by targeting the ERK1/2 and Bcl-2 pathways.

Human bone marrow mesenchymal stem cells (hBMMSCs) are a promising cell source for bone engineering owing to their high potential to differentiate into osteoblasts. The objective of the present study is to assess microRNA-126 (miR-126) and examine its effects on the osteogenic differentiation of hBMMSCs. In this study, we investigate the role of miR-126 in the progression of osteogenic differentiation (OD) as well as the apoptosis and inflammation of hBMMSCs during OD induction. OD is induced in hBMMSCs, and matrix mineralization along with other OD-associated markers are evaluated by Alizarin Red S (AR) staining and quantitative PCR (qPCR). Gain- and loss-of-function studies are performed to demonstrate the role of miR-126 in the OD of hBMMSCs. Flow cytometry and qPCR-based cytokine expression studies are performed to investigate the effect of miR-126 on the apoptosis and inflammation of hBMMSCs. The results indicate that miR-126 expression is downregulated during the OD of hBMMSCs. Gain- and loss-of function assays reveal that miR-126 upregulation inhibits the differentiation of hBMMSCs into osteoblasts, whereas the downregulation of miR-126 promotes hBMMSC differentiation, as assessed by the determination of osteogenic genes and alkaline phosphatase activity. Furthermore, the miR-126 level is positively correlated with the production of inflammatory cytokines and apoptotic cell death. Additionally, our results suggest that miR-126 negatively regulates not only B-cell lymphoma 2 (Bcl-2) expression but also the phosphorylation of extracellular signal­regulated protein kinase (ERK) 1/2. Moreover, restoring ERK1/2 activity and upregulating Bcl-2 expression counteract the miR-126-mediated suppression of OD in hBMMSCs by promoting inflammation and apoptosis, respectively. Overall, our findings suggest a novel molecular mechanism relevant to the differentiation of hBMMSCs into osteoblasts, which can potentially facilitate bone formation by counteracting miR-126-mediated suppression of ERK1/2 activity and Bcl-2 expression.

Plasma 8-OHdG act as a biomarker for steroid-induced osteonecrosis of the femoral head.

BACKGROUND: Oxidative stress was closely related to the occurrence and development of Steroid-induced osteonecrosis of the femoral head (SIONFH). 8-hydroxy-2'-deoxyguanosine (8-OHdG) is a important index of oxidative stress. The aim of this study is to investigate the role of 8-OHdG in the development of SIONFH. METHODS: From May 2021 and November 2021, 33 patients diagnosed with SIONFH and 26 healthy controls were recruited in this study. Assessment included the radiography and pathology evaluation of clinical bone tissue, expression position and level of 8-OHdG, level of plasma 8-OHdG, as well as the receiver operating characteristic (ROC) curve. RESULTS: We observed that expression levels of 8-OHdG in bone samples decreased with Association Research Circulation Osseous (ARCO) stages. Plasma 8-OHdG levels were significantly increased in the SIONFH group compared to the healthy control group. Plasma 8-OHdG level of pre-collapse patients was higher than that of post-collapse patients, the decreased plasma 8-OHdG level was related to higher ARCO stages. CONCLUSION: Plasma 8-OHdG may represent potential biomarkers during SIONFH at different stages. Higher plasma 8-OHdG levels indicated early stage of SIONFH. The current study provided new clues for early diagnosis and treatment for SIONFH.

Lateral classification system predicts the collapse of JIC type C1 nontraumatic osteonecrosis of the femoral head: a retrospective study.

PURPOSES: The aim of this study was to construct a lateral classification system for nontraumatic osteonecrosis of femoral head (NONFH) through three-dimensional reconstruction of the necrotic area to assist in evaluating the prognosis of patients with JIC type C1. METHODS: Retrospective analysis of patients with JIC type C1 NONFH from January 2018 to December 2020. All patients were followed up for more than 3.5 years. The patients were divided into collapse group and non-collapse group according to whether the femoral head collapsed during the follow-up.Lateral classification system for femoral head necrosis is constructed through three-dimensional reconstruction of the necrotic area.Comparison of lateral classification system,midsagittal necrosis angle(MNA)and general data between the two groups.Furthermore, ROC curve analysis and survival analysis were performed. RESULTS: 318 patients were included in this study.There was a significant difference between the two groups in the lateral classification system (P < 0.05). In addition, the MNA in the collapsed group was significantly greater than that in the non-collapse group(P < 0.05). As revealed by the results of ROC analysis, the cutoff point of MNA was 104.5° (P < 0.05).According to the survivorship analysis, the mean survival time of the hips of patients with MNA less than 104.5°was greater than that of patients with MNA over 104.5° (P < 0.05). The survival rates of 3.5 years femoral head were 45.8%, 33.7%, 14.8%, 93.0%, and 100% for lateral classification system 1, 2, 3, 4, and 5, respectively. CONCLUSION: Necrosis involving the anterior aspect of the femoral head is an important risk factor for collapse. The Lateral classification system can effectively predict the femoral head collapse in JIC C1 type NONFH patients, supplementing the deficiency of JIC classification in evaluating the front of the femoral head.

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

BACKGROUND: Wnt/ß-catenin signaling pathway is closely related to the pathogenesis Osteonecrosis of the femoral head (ONFH). ß-catenin, as a major component of Wnt signaling pathway, plays a vital role in the proliferation of osteoblasts. But the effect of altering ß-catenin level on the early diagnosis and staging of ONFH has not been studied. Our purpose is to investigate the role of ß-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 ß-catenin as well as the plasma ß-catenin level. We investigated the level of ß-catenin from the serum and tissue samples using ELISA and Western Blot assay. We also evaluated the expression of ß-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 ß-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 ß-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 ß-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 ß-catenin may play a vital role in the progress of ONFH and the level of ß-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.

Outcomes of surgical hip dislocation combined with bone graft for adolescents and younger adults with osteonecrosis of the femoral head: a case series and literature review.

BACKGROUND: Osteonecrosis of the femoral head (ONFH) may occur in the adolescent and younger adults (AYAs). Total hip arthroplasty (THA) is not the best treatment option for younger patients. Surgical hip dislocation (SHD) combined with bone graft can be used in patients at different stages to reconstruct the bone structure in the head and delay the replacement time. The purpose of this study was to evaluate the effect and potential influencing factors of this surgery for ONFH in AYA patients.  METHODS: We conducted a literature review and a retrospective research of our own cases. The Pubmed, Cochrane Library, EMBASE and CNKI databases were searched from 1 January 2001 to 1 October 2021, for clinical studies. A retrospective case series study of 34 patients (38 hips) treated with SHD combined with bone graft was performed. RESULTS: A total of 13 studies were included and the results showed that SHD combined with bone grafts had better clinical results for patients with pre- or early post-collapse. In the case series study, we retrospectively analyzed 34 patients (38 hips), and the mean follow-up time was 40.77 ± 15.87 months. One patient died and three patients were converted to THA finally. The post-collapse degree and post-lesion size were better than those before the operation (P < 0.05). The iHOT-12 at the last follow-up was significantly higher than that before the operation (P < 0.05). There were significant differences in the results of hip Harris score (HHS), visual analogue scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) before the operation, 2 years after the operation and at the last follow-up, but the difference was not related to the follow-up time (P < 0.05). There were no significant differences in the final clinical score and arthritic changes among different Japanese Investigation Committee (JIC) classification, the degree of collapse and the size of the necrotic (P > 0.05). CONCLUSIONS: In AYA patients, SHD combined with bone grafting is a potentially good option for hip preservation in ONFH. The differences in JIC classification, collapse degree and lesion size did not affect the final clinical function and the risk of osteoarthritis. Even for very severe cases at collapsed stage, good short-term clinical effects can still be achieved by SHD combined with bone graft. TRIAL REGISTRATION: ChiCTR2100055079 .retrospectively registered.

Composite indices of femoral neck strength predicts the collapse of steroid-associated osteonecrosis of the femoral head: a retrospective study.

PURPOSES: The purpose of this study was to investigate the predictive effect exerted by composite indices of femoral neck strength (compressive strength index (CSI), bending strength index (BSI) and impact strength index (ISI) on the femoral head collapse in steroid-associated ONFH patients. METHODS: Nonoperative steroid-associated osteonecrosis of the femoral head (ONFH) patients from 2017 to 2019 were selected. The patients fell into the collapsed group and the non-collapsed group according to whether the femoral head collapsed. CSI, BSI and ISI were calculated. Moreover, bone turnover markers were measured. The statistical analysis was conducted on the predictive effects of composite indices of femoral neck strength and bone turnover index on ONFH collapse. RESULTS: A total of 62 patients were included. The mean CSI, BSI and ISI were significantly lower in the collapsed group than those in the non-collapsed group (P < 0.05). CSI, ISI,t-P1NP and ß-CTx were suggested as the protective risk factors for the femoral head collapse in ONFH patients. The ISI area under the curve values was 0. 878.The mean survival time of the hips of patients with ISI greater than 0.435 was greater (P < 0.05) than that of patients with ISI less than 0.435. CONCLUSION: The composite indices of femoral neck strength can predict steroid-associated ONFH femoral head collapse more effectively than the bone turnover markers. The ISI value of 0.435 is a potential cut-off value, lower than this value can predict the early collapse of steroid-associated ONFH.

Osteoporosis is associated with varus deformity in postmenopausal women with knee osteoarthritis: a cross-sectional study.

BACKGROUND: Varus deformity of the knee is a common pathological characteristic in knee osteoarthritis (KOA), and not enough attention has been given to the relationship between knee varus deformity and the state of systemic bone mass. The purpose of this study was to evaluate the potential relationship between bone mineral density (BMD) and varus deformity in postmenopausal women with KOA. METHODS: A total of 202 postmenopausal women with KOA(KL grade ≥ 2)in our department from January 2018 to June 2020 were reviewed in this cross-sectional study. The hip-knee-ankle angle of the lower extremity (HKA), medial distal femoral angle (MDFA), medial proximal tibial angle (MPTA), and the angle of the joint line (JLCA) were measured in all patients. According to the HKA Angle, these participants were divided into the varus deformity group (HKA < 175.3°) and the normal limb alignment group (175.3°≤ HKA ≤ 180.3°). The BMD of the lumbar (L1-L4), left femoral neck, and left hip were measured by dual-energy X-ray absorptiometry in all patients. The difference in BMD between the knee varus deformity group and the normal limb alignment group was compared, and the relationship between the different angles of limb alignment and the BMD values at different sites was evaluated. RESULTS: There were 144 cases (71.3 %) in the varus deformity group and 58 cases (28.7 %) in the normal limb alignment group. BMD at different joint sites within the knee varus deformity group was lower than of the normal limb alignment group, and the prevalence of osteoporosis was higher. After adjusting for confounding factors such as age, BMI, pain duration, and affected side, binary logistic regression showed that osteoporosis was an independent risk factor for varus deformity of KOA, and multiple linear regression showed that the BMD of spine, femoral neck, and hip was significantly associated with varus deformity of KOA. Pearson correlation analysis showed that BMD of the lumbar spine (L1-L4), left femoral neck and left hip joint were positively correlated with the HKA, but negatively correlated with JLCA. MPTA was positively correlated with the left femoral neck and left hip joint BMD, but not correlated with lumbar bone density. Furthermore, in the normal limb alignment group, the HKA was only negatively correlated with JLCA, but not significantly correlated with MDFA and MPTA. In the varus deformity group, the HKA was not only negatively correlated with JLCA but also positively correlated with MDFA and MPTA. CONCLUSIONS: Osteoporosis should be a major risk factor for varus deformity in postmenopausal women with KOA. The progression of varus deformity of the knee should be concerned in postmenopausal women who simultaneously has KOA and osteoporosis.

Avascular necrosis after femoral neck fracture in children and adolescents: poor prognosis and risk factors.

INTRODUCTION: Avascular necrosis (AVN) after femoral neck fracture (FNF) is a rare and severe paediatric condition, but only few studies described its prognosis and risk factors. The present study aimed to evaluate the outcomes and independent factors for poor prognosis of AVN after FNF in children and adolescents. METHOD: This retrospective study included children and adolescents with AVN after FNF who received conservative treatment (CT group) or non-vascularized bone grafting (NVBG group) between 2000 and 2018. The primary outcomes were the risk of hip arthritis (Tönnis grade) and hip deformity risk (Stulberg classification). All patients were followed for at least two years to assess AVN progression. RESULTS: Study included 81 patients. In the CT group, 23/43 patients (53.4%) developed hip arthritis, and 24/43 patients (55.8%) showed hip deformity. In the NVBG group, 23/38 patients (60.5%) developed hip arthritis, and 34/38 patients (89.5%) had a hip deformity. The multivariable analysis indicated that NVBG surgery had no significant effect on the outcomes. Post-treatment femoral head collapse (P = 0.05, OR = 3.80, 95% CI = 1.01-14.29) and post-treatment hip subluxation (P = 0.01, OR = 2.85, 95% CI = 2.31-129.56) were independent risk factors for severe hip arthritis. Post-treatment femoral head collapse (P < 0.01, OR = 7.64, 95% CI = 3.23-18.04) and pre-treatment hip subluxation (P = 0.02, OR = 7.33, 95% CI = 1.44-37.41) were independent risk factors for severe hip deformity. CONCLUSION: Neither CT nor NVBG have demonstrated superiority regarding long-term outcomes in patients with AVN after FNF. Upon the disease progression to severe collapse with subluxation and severe arthritis, further hip preservation attempts could be futile.

Porous tantalum rod implantation is associated with low survival rates in patients with type C2 osteonecrosis of the femoral head but has no effect on the clinical outcome of conversion total hip arthroplasty: a retrospective study with an average 8-year follow-up.

BACKGROUND: Our study aimed to investigate the clinical outcomes and survival rates following porous tantalum rod surgery (PTRS) and conversion total hip arthroplasty (THA) subsequent to failed PTRS. METHODS: A total of 38 subjects (40 hips) with osteonecrosis of the femoral head (ONFH) were included in this retrospective study between January 2008 and December 2011. All subjects were evaluated before surgery by using the Association Research Circulation Osseous (ARCO) classification system, the Japan Investigation Committee (JIC) classification and the Harris hip score (HHS). The endpoint of this study was set as final follow-up (including the survival time of PTRS and conversion THA). The rates of radiological progression were also evaluated. Patients who received conversion THA were further followed and compared to a control group of 58 patients with ONFH who underwent primary THA. RESULTS: The mean follow-up time was 120.7 ± 9.2 (range, 104-143) months, and the overall survival rate was 75% at 96 months (ARCO stage II: 81.5%; stage III: 38.5%; JIC type C1: 83.3%; C2: 30%). The HHS before surgery was 59 (55-61), in contrast to 94 (91-96) at 96 months follow-up (P < 0.01). HHS in stage III show a significant poorer result compared to stage II at 24 months. HHS in Type C2 group show no significant difference compared to HHS before surgery at 24 and 60 months follow up (P = 0.91, P = 0.30). Twelve hips requiring secondary THA were followed for 66.9 ± 31.7 months, and control hips that underwent primary THA was followed for 75.4 ± 14.9 months. The HHS in the conversion group was 89 (86-93) and that in the primary THA group was 92 (79-95, P = 0.09) at the 5-year follow-up. CONCLUSION: In the mid-term follow-up, porous tantalum implants showed an encouraging survival rate in symptomatic patients in early stages (ARCO stage II) or with limited necrotic lesions (JIC type C1). In addition, our results did not demonstrated any difference between primary THA and conversion THA.

EGFL7: Master regulator of cancer pathogenesis, angiogenesis and an emerging mediator of bone homeostasis.

Epidermal growth factor-like domain-containing protein 7 (EGFL7), a member of the epidermal growth factor (EGF)-like protein family, is a potent angiogenic factor expressed in many different cell types. EGFL7 plays a vital role in controlling vascular angiogenesis during embryogenesis, organogenesis, and maintaining skeletal homeostasis. It regulates cellular functions by mediating the main signaling pathways (Notch, integrin) and EGF receptor cascades. Accumulating evidence suggests that Egfl7 plays a crucial role in cancer biology by modulating tumor angiogenesis, metastasis, and invasion. Dysregulation of Egfl7 has been frequently found in several types of cancers, such as malignant glioma, colorectal carcinoma, oral and oesophageal cancers, gastric cancer, hepatocellular carcinoma, pancreatic cancer, breast cancer, lung cancer, osteosarcoma, and acute myeloid leukemia. In addition, altered expression of miR-126, a microRNA associated with Egfl7, was found to play an important role in oncogenesis. More recently, our study has shown that EGFL7 is expressed in both the osteoclast and osteoblast lineages and promotes endothelial cell activities via extracellular signal-regulated kinase (ERK), signal transducer and activator of transcription 3 (STAT3), and integrin signaling cascades, indicative of its angiogenic regulation in the bone microenvironment. Thus, understanding the role of EGFL7 may provide novel insights into the development of improved diagnostics and therapeutic treatment for cancers and skeletal pathological disorders, such as ischemic osteonecrosis and bone fracture healing.

Conductive Tungsten Oxide Nanosheets for Highly Efficient Hydrogen Evolution.

Exploring efficient and economical electrocatalysts for hydrogen evolution reaction is of great significance for water splitting on an industrial scale. Tungsten oxide, WO3, has been long expected to be a promising non-precious-metal electrocatalyst for hydrogen production. However, the poor intrinsic activity of this material hampers its development. Herein, we design a highly efficient hydrogen evolution electrocatalyst via introducing oxygen vacancies into WO3 nanosheets. Our first-principles calculations demonstrate that the gap states introduced by O vacancies make WO3 act as a degenerate semiconductor with high conductivity and desirable hydrogen adsorption free energy. Experimentally, we prepared WO3 nanosheets rich in oxygen vacancies via a liquid exfoliation, which indeed exhibits the typical character of a degenerate semiconductor. When evaluated by hydrogen evolution, the nanosheets display superior performance with a small overpotential of 38 mV at 10 mA cm-2 and a low Tafel slope of 38 mV dec-1. This work opens an effective route to develop conductive tungsten oxide as a potential alternative to the state-of-the-art platinum for hydrogen evolution.

Prognostic analysis of different morphology of the necrotic-viable interface in osteonecrosis of the femoral head.

PURPOSE: The purpose of this study was to investigate the collapse progression in different morphologies of the necrotic-viable interface in osteonecrosis of the femoral head (ONFH). METHODS: A total of 168 patients (202 hips) with Association Research Circulation Osseous (ARCO) stage II ONFH were included. Ending with the collapse of the femoral head, all patients received conservative treatment but without surgical intervention and were followed for three to 91 months. Bilateral hip-joint radiographs and magnetic resonance imaging (MRI) were examined, and the largest layer of necrosis within the coronal section of MRI images was selected together with its anteroposterior radiograph to observe the morphology of the necrotic-viable interface. The morphology was divided into four types: I, type transverse; II, type "V"; III, type zigzag; IV, type closed. The collapse rate and the time to collapse in different morphologies were assessed. RESULTS: A total of 120 hips collapsed in two years or less, 61 were type-I, 51 were type-II, and 8 were type-III. Non-collapse occurred in all 17 hips with type-IV ONFH during long-term follow-up. In 202 hips with ARCO stage-II ONFH, the collapse rate in type-I ONFH was significantly higher than that of type-II and type-III ONFH (P < 0.01 for both). The time to collapse was markedly shortened. CONCLUSIONS: The risk of ONFH-induced collapse is influenced by the morphology of the necrotic-viable interface. Effective mechanical support for preventing the collapse of the femoral head is necessary when the morphology of the necrotic-viable interface is type transverse.

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.

Serum serotonin concentration associated with bone mineral density in Chinese postmenopausal women.

Recent studies have shown that circulating serotonin plays a potential role in bone metabolism. However, conflicting results have been reported for the relationship between serum serotonin concentrations and bone mineral density (BMD). We investigated whether the serum serotonin concentrations related to BMD in Chinese postmenopausal women. Serum serotonin and bone turnover concentrations of 117 premenopausal women and 262 asymptomatic postmenopausal women were analyzed by enzyme-linked immunosorbent assay. BMD at the lumbar spine and femoral neck was measured by dual energy X-ray absorptiometry. The relationship between serotonin and BMD was investigated. The postmenopausal women had lower mean serum serotonin concentrations compared to the premenopausal women. Serotonin concentrations were negatively associated with age, weight, BMI, fat mass, and ß-CTX concentrations in postmenopausal women. No significant correlations were found between serotonin and these parameters in premenopausal women. In postmenopausal women, age- and BMI-adjusted serotonin concentrations were positively correlated with BMD of the lumbar spine and femoral neck. Multiple regression analyses showed serum serotonin and ß-CTX were the predictors for lumbar spine BMD. Only serum serotonin was the determinant for femoral neck BMD. In conclusion, lower serum serotonin concentrations are linked to low lumbar spine and femoral neck BMD in postmenopausal women.

Bajijiasu Abrogates Osteoclast Differentiation via the Suppression of RANKL Signaling Pathways through NF-κB and NFAT.

Pathological osteolysis is commonly associated with osteoporosis, bone tumors, osteonecrosis, and chronic inflammation. It involves excessive resorption of bone matrix by activated osteoclasts. Suppressing receptor activator of NF-κB ligand (RANKL) signaling pathways has been proposed to be a good target for inhibiting osteoclast differentiation and bone resorption. Bajijiasu-a natural compound derived from Morinda officinalis F. C. How-has previously been shown to have anti-oxidative stress property; however, its effect and molecular mechanism of action on osteoclastogenesis and bone resorption remains unclear. In the present study, we found that Bajijiasu dose-dependently inhibited RANKL-induced osteoclast formation and bone resorption from 0.1 mM, and reached half maximal inhibitory effects (IC50) at 0.4 mM without toxicity. Expression of RANKL-induced osteoclast specific marker genes including cathepsin K (Ctsk), nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), tartrate resistant acid phosphatase (TRAcP), vacuolar-type H⁺-ATPase V0 subunit D2 (V-ATPase d2), and (matrix metalloproteinase-2 (MMP2) was inhibited by Bajijiasu treatment. Luciferase reporter gene studies showed that Bajijiasu could significantly reduce the expression and transcriptional activity of NFAT as well as RANKL-induced NF-κB activation in a dose-dependent manner. Further, Bajijiasu was found to decrease the RANKL-induced phosphorylation of extracellular signal-regulated kinases (ERK), inhibitor of κB-α (IκB-α), NFAT, and V-ATPase d2. Taken together, this study revealed Bajijiasu could attenuate osteoclast formation and bone resorption by mediating RANKL signaling pathways, indicative of a potential effect of Bajijiasu on osteolytic bone diseases.

Effect of glucocorticoid withdrawal on glucocorticoid inducing bone impairment.

Glucocorticoid (GC) withdrawal after a short-term use was common in clinical practice like immediate post-transplant period. However, previous studies without setting age-control group failed to determine whether the BMD recovery was sufficient and whether it is necessary to accept anti-osteoporosis therapy after GC withdrawal. The aim of this study was to investigate the effect of GC withdrawal on bone impairment in glucocorticoid-induced osteoporosis (GIOP) rats. Twenty-four female Sprague-Dawley rats (3 months' old) were randomly divided into two treatment groups: an untreated age-control group (Con, n = 12); another group receiving a dexamethasone injection (DEXA, n = 12). Animals in the Con group were euthanized at 3rd month (M3) and 6th month (M6), respectively. Six rats in the DEXA group were euthanized at 3rd month (M3), whereas GC intervention was withdrew in the remaining animals of DEXA group, which were euthanized at the end of 6th month (M6). Bone mass, bone microarchitecture, biomechanical properties of vertebrae, morphology, serum levels of PINP and ß-CTX were evaluated. Compared with the Con(M3) group, the Con(M6) group showed significantly better bone quantity, morphology and quality. Compared with the Con(M3) group, the DEXA (M3) group showed significantly lower BMC, BMD, BS/TV, BV/TV, Tb.N, Tb.Th, vBMD, bone strength, compressive displacement, energy absorption capacity, PINP levels, ß-CTX levels, and damaged trabecular morphology. And the same change trend was observed in the comparison between the Con(M6) group and DEXA (M6) group. Compared with the DEXA (M3) group, the DEXA (M6) group showed significantly higher BMC, BMD and AREA, but no significant difference in BS/TV, BV/TV, SMI, Tb.N, Tb.Th, Tb.Sp, vBMD, bone strength, bone stiffness, compressive displacement, energy absorption capacity, PINP levels, ß-CTX levels, and improvement in trabecular morphology was observed. These results indicate that the reverse effect of GC withdrawal for 3 months on bone impairment in GIOP rats was insufficient, which implied that related anti-osteoporosis treatment might be still necessitated after GC withdrawal in clinical setting.

Serum osteopontin levels in relation to bone mineral density and bone turnover markers in postmenopausal women.

Osteopontin (OPN) is an extracellular matrix protein that is expressed in bone cells such as osteoblast and osteocytes and associated with bone turnover and bone mineral density (BMD) in postmenopausal women. Here, we aimed to investigate the relationship between circulating OPN levels and BMD in postmenopausal women in Southern China. A total of 362 postmenopausal women were consecutively recruited into this study from 2011-2013. Serum levels of OPN, receptor activator of nuclear factor kappa B (NF-κB) ligand (RANKL), and bone turnover markers were analyzed. BMD was measured by dual energy X-ray absorptiometry. Osteoporosis and osteopenia were diagnosed according to the World Health Organization criteria. Serum OPN levels were remarkably higher in the osteoporotic group than those in the osteopenic and normal groups (all p < 0.001). The cut-off value of OPN for diagnosing postmenopausal osteoporosis was 10.1 ng/mL, which had a sensitivity of 89.5%, a specificity of 70.8%, and an area under curve of 0.953. Serum OPN was negatively correlated with parathyroid hormone (PTH), lumbar spine BMD, and femoral neck BMD (r = -0.25, p = 0.004; r = -0.66, p < 0.001; r = -0.28, p = 0.001; respectively) and positively associated with type I procollagen amino-terminal propeptide (PINP), carboxy-terminal cross-linking telopeptide of type I collagen (CTX), and RANKL (r = 0.20, p = 0.020; r = 0.17, p = 0.036; r = 0.19, p = 0.028, respectively) in the osteoporotic group. In multiple regression analyses, lumbar spine BMD, PTH and RANKL were the predictors for serum OPN levels. In conclusion, OPN serum levels are negatively related to BMD and positively correlated with bone turnover levels in this group of Chinese postmenopausal women.

Relation of serum 25 hydroxyvitamin D levels to bone mineral density in southern Chinese postmenopausal women: A preliminary study.

BACKGROUND & OBJECTIVES: Vitamin D insufficiency is prevalent in postmenopausal women and has been related to low bone mineral density (BMD). However, controversial results have been reported for the relationship between serum 25-hydroxyvitamin D [25(OH)D] levels and BMD. This study was done to investigate whether serum 25(OH)D levels were associated with BMD in postmenopausal women living in Guangzhou in southern China. METHODS: This cross-sectional study involved 119 asymptomatic postmenopausal women, aged 48-85 yr, who were consecutively selected from Guangzhou city. BMD was measured at the lumbar spine and femoral neck. The correlation between serum 25(OH)D levels and BMD wes investigated. RESULTS: With increasing serum 25(OH)D levels categorized as <20, 20-30, and ≥ 30ng/ml, the PTH levels decreased gradually ( P=0.031). Bivariate correlation analyses showed an inverse relationship between serum 25(OH)D and PTH levels after controlling for age and BMI (r=-0.209, P=0.023). Although subjects with vitamin D<30 ng/ml had significantly lower BMD, age- and BMI-adjusted serum 25(OH)D was weakly correlated with BMD at femoral neck (r=0.185, P0.045), and not at lumbar spine (r=0.172, p =0 0.063). In multiple regression analyses, serum 25(OH)D was a predictor for BMD at femoral neck (R 2= 0.424). However, serum ß-CTX was a determinant for BMD at lumbar spine (R 2= 0.361). INTERPRETATION & CONCLUSIONS: Serum 25(OH)D levels showed a positive correlation with BMD at femoral neck and serum ß-CTX levels were inversely correlated with BMD at lumbar spine in postmenopausal women. Further studies are needed to elucidate the clinical impact of these findings.