Serum interleukin 6 is a major predictor of bone loss in women specific to the first decade past menopause

Association between osteoporosis and the rate of telomere shortening

A shorter leukocyte telomere length (LTL) is reported to be associated with age-related diseases, including osteoporosis. Many studies have tried identifying the association between LTL and osteoporosis, although it remains controversial. This study aimed to determine whether osteoporosis is independently associated with LTL shortening in a prospective longitudinal cohort. The KBASE study is an independent multicenter prospective cohort in South Korea, which began in 2014. We compared the LTL values for each participant at baseline and over a 2-year follow-up period. Boxplots were used to demonstrate the differences in the change in LTL over a 2-year follow-up according to osteoporosis. Multivariable linear regression was conducted to identify whether osteoporosis is independently associated with the rate of telomere shortening. A total of 233 subjects (from 55 to 88 years) from the KBASE cohort were finally enrolled in the study. We observed that the LTL decreased by approximately 1.2 kbp over 2 years. While the LTL decreased as age increased, the rate of LTL shortening did not increase with age. Multivariable linear regression analysis indicated that only osteoporosis was independently associated with rapid LTL shortening over 2 years (B, -8.08; p = 0.038). We sought to identify an association between osteoporosis and LTL shortening in an independent prospective cohort. We found that participants with osteoporosis had significantly faster LTL shortening over 2 years than those without osteoporosis. We hope this study will help elucidate the underlying mechanisms in the relationship between LTL and osteoporosis in the future.

Anxiety disorders are associated with reduced bone mineral density in men: Findings from the Geelong Osteoporosis Study

OBJECTIVE

Certain psychiatric disorders, including depression, appear to impact adversely on bone health. Anxiety disorders are highly prevalent but few studies have examined their effects on bone tissue. This study investigated the effect of anxiety disorders on bone mineral density (BMD).

METHODS

This prospective cohort study used data from the Geelong Osteoporosis Study. Participants were women and men aged ≥20 years randomly selected from the electoral roll and followed up for a mean of 14.7 and 11.0 years, respectively. Participants were assessed for a lifetime history of an anxiety disorder using the Structured Clinical Interview for DSM-IV-TR. BMD in the lumbar spine and femoral neck was measured using dual-energy x-ray absorptiometry.

RESULTS

Eight hundred and ninety women and 785 men participated in the study. Adjusting for sociodemographic, biometric and lifestyle factors, medical comorbidities and medication use, anxiety disorders were associated with reduced BMD at the lumbar spine (partial η2  = 0.006; p = 0.018) and femoral neck (partial η2  = 0.006; p = 0.003) in men. These associations became non-significant when men with a history of comorbid mood disorders were excluded from the analysis. There was no significant association between anxiety disorders and BMD in women (p ≥ 0.168).

CONCLUSIONS

Anxiety disorders are associated with reduced BMD in men. This effect may be mediated by comorbid depression.

Menopause-Related Changes in Body Composition Are Associated With Subsequent Bone Mineral Density and Fractures: Study of Women's Health Across the Nation

During the menopause transition (MT), lean mass decreases and fat mass increases. We examined the associations of these body composition changes during the MT (2 years before to 2 years after the final menstrual period) with bone mineral density (BMD) at the end of the MT and fracture after the MT. We included 539 participants from the Study of Women's Health Across the Nation who were not taking bone-beneficial or bone-detrimental medications before or during the MT. Using multivariable linear regression, we assessed the independent associations of % lean mass loss and % fat mass gain during the MT (mutually adjusted) with femoral neck (FN) and lumbar spine (LS) BMD at the end of the MT, adjusted for pre-MT BMD, pre-MT lean and fat mass, race/ethnicity, Study of Women's Health Across the Nation (SWAN) study site, age, and cigarette use. We used Cox proportional hazards regression to quantify the relations of % lean loss and % fat gain during the MT with fracture after the MT. The Cox model was adjusted for the covariates above plus post-MT use of bone-detrimental medications, and censored at the first use of bone-beneficial medications; we further controlled for FN or LS BMD at the end of the MT. Adjusted for covariates, each standard deviation (SD) (6.9%) increment in lean mass loss was associated with 0.010 g/cm2 lower FN BMD (p < 0.0001); each SD (19.9%) increment in fat mass gain was related to 0.026 g/cm2 greater FN (p = 0.009) and LS (p = 0.03) BMD. Each SD increment in lean mass loss and fat mass gain was associated with 63% (p = 0.001) and 28% (p = 0.05) greater fracture hazard after the MT; associations were essentially unchanged by BMD adjustment. MT-related lean mass loss and fat mass gain were associated differentially with BMD; both were independently related to more fractures. Mitigating MT-related body composition changes may reduce fracture risk. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Overview on postmenopausal osteoporosis and periodontitis: The therapeutic potential of phytoestrogens against alveolar bone loss

Osteoporosis and periodontitis are two major chronic diseases of postmenopausal women. The association between these two diseases are evident through systemic bone loss and alveolar bone loss. Both postmenopausal osteoporosis and periodontitis impose a considerable personal and socioeconomic burden. Biphosphonate and hormone replacement therapy are effective in preventing bone loss in postmenopausal osteoporosis and periodontitis, but they are coupled with severe adverse effects. Phytoestrogens are plant-based estrogen-like compounds, which have been used for the treatment of menopause-related symptoms. In the last decades, numerous preclinical and clinical studies have been carried out to evaluate the therapeutic effects of phytoestrogens including bone health. The aim of this article is to give an overview of the bidirectional interrelationship between postmenopausal osteoporosis and periodontitis, summarize the skeletal effects of phytoestrogens and report the most studied phytoestrogens with promising alveolar bone protective effect in postmenopausal osteoporosis model, with and without experimental periodontitis. To date, there are limited studies on the effects of phytoestrogens on alveolar bone in postmenopausal osteoporosis. Phytoestrogens may have exerted their bone protective effect by inhibiting bone resorption and enhancing bone formation. With the reported findings on the protective effects of phytoestrogens on bone, well-designed trials are needed to better investigate their therapeutic effects. The compilation of outcomes presented in this review may provide an overview of the recent research findings in this field and direct further in vivo and clinical studies in the future.

IL-6 and Leptin Are Potential Biomarkers for Osteoporotic Fracture Risk Assessment and Prediction of Postmenopausal Women with Low Bone Mass: A Follow-Up Study Using a Regional Sample Cohort

Osteoporotic fracture, a major complication which is known as the outcome postmenopausal osteoporosis, seriously threatens the health of postmenopausal women. At present, the traditional osteoporotic fracture prediction methods are characterized by inconvenient application and time-consuming statistical results, while predictive serum biomarkers can make up for this shortcoming. Accurate and advanced risk prediction of osteoporotic fracture is meaningful to early prevention and intervention, effectively avoiding the risk of this disease and the secondary fracture in the surgical treatment. In this study, based on the BEYOND cohort, a 2-year follow-up study was conducted after subjects participated to survey if OF occurred. Independent sample t-test and Mann–Whitney U-test were used to analyze the differences of bone metabolism biomarkers between the OF and non-OF group. Cox proportional hazard model was used to screen the potential biomarkers might be used to predict OF risk. ROC curves and AUCs were used to analyze the predictive accuracy, and the Delong's test was used to compare the differences between the AUCs. 15 postmenopausal women with low bone mass and OF were found, and other 60 subjects without OF were matched with 1 : 4, age, and BMI classification as control group. The serum IL-6 (OR = 1.139, 95%CI = 1.058 − 1.226) and leptin (OR = 0.921, 95%CI = 0.848 − 1.000) were found as OF risk predictive biomarkers for postmenopausal women with low bone mass with high accuracy (IL − 6 = 0.871) (leptin = 0.813) and accuracy enhanced when they were combined (AUC = 0.898). The results of Delong's test showed that the difference of AUC between leptin and IL-6&Leptin was meaningful (P = 0.024) but meaningless between IL-6 and leptin (P = 0.436), IL-6 and IL-6&Leptin (P = 0.606). To sum up, IL-6 and leptin are the predictive biomarkers of OF for postmenopausal women with low bone mass. The IL-6 can improve the prediction accuracy of leptin (P = 0.024), but not vice versa (P = 0.606). Trial Information. Registered on the Chinese Clinical Trial Registry already. (Registration Number: ChiCTR-SOC-17013090).

Osteoporosis and the long-term risk of peripheral artery disease: a population-based longitudinal follow-up study in Taiwan

INTRODUCTION

Osteoporosis has been linked to atherosclerotic diseases such as coronary heart disease and ischemic stroke. However, the relationship between osteoporosis and peripheral artery disease (PAD) has not been investigated. This study aims to evaluate the risk of PAD in patients with osteoporosis and the impact of sex on this association.

METHODS

This population-based study used the Longitudinal Health Insurance Database 2005, a subset of Taiwan's National Health Insurance research database. A total of 54,324 individuals between 40 and 79 years old were included in this study. The osteoporosis group (n = 27,162) consisted of patients with a diagnosis of osteoporosis between January 1, 2002, and December 31, 2006, while the non-osteoporosis group were patients without osteoporosis selected by stratified random sampling (n = 27,162). The primary outcome was the occurrence of newly diagnosed PAD. Cox proportional hazard regression modeling was used to evaluate the association between osteoporosis and the risk of PAD, with adjustment for the baseline characteristics.

RESULTS

The risk of PAD for the osteoporosis group was 28% higher than for the non-osteoporosis group (adjusted hazard ratio (HR) 1.28, 95% confidence interval [CI] 1.20-1.36, p < 0.001), and the PAD-free survival rate was lower in the osteoporosis group (p < 0.001). Sex-stratified analysis revealed a similar HR magnitude between osteoporotic men (HR 1.36; 95% CI 1.19-1.57) and women (HR 1.25; 95% CI 1.17-1.35), compared with their non-osteoporotic counterparts.

CONCLUSION

This study found an increased long-term risk of PAD in both men and women with osteoporosis. Osteoporosis has been associated with increased risks of atherosclerotic diseases. However, the relationship between osteoporosis and peripheral artery disease remains uncertain. The present population-based longitudinal follow-up study showed that patients with osteoporosis are at an increased risk of developing peripheral artery disease.

Aging versus youth: Endocrine aspects of vulnerability for COVID-19

Coronavirus Disease 2019 (COVID-19) is characterized with a wide range of clinical presentations from asymptomatic to severe disease. In patients with severe disease, the main causes of mortality have been acute respiratory distress syndrome, cytokine storm and thrombotic events. Although all factors that may be associated with disease severity are not yet clear, older age remains a leading risk factor. While age-related immune changes may be at the bottom of severe course of COVID-19, age-related hormonal changes have considerable importance due to their interactions with these immune alterations, and also with endothelial dysfunction and comorbid cardiometabolic disorders. This review aims to provide the current scientific evidence on the pathogenetic mechanisms underlying the pathway to severe COVID-19, from a collaborative perspective of age-related immune and hormonal changes together, in accordance with the clinical knowledge acquired thus far.

The cross-talk between matrix metalloproteinase-9, RANKL/OPG system and cardiovascular risk factors in ovariectomized rat model of postmenopausal osteoporosis

Epidemiology and pathogenesis of cardiovascular diseases (CVD) and osteoporosis are strikingly overlapping. This study presents matrix metalloproteinase-9 (MMP-9), as a simple molecular link more consistently associated with the pathophysiology of both osteoporosis and CVD risk factors. 40 adult female rats were randomly distributed into 4 groups [control sham-operated, untreated osteoporosis, carvedilol-treated osteoporosis and alendronate-treated osteoporosis]. After 8 weeks, blood samples were collected to estimate Lipid profile (Total cholesterol, HDL, Triglycerides), inflammatory markers (IL-6, TNF alpha, CRP and NO), and Bone turnover markers (BTM) (Alkaline phosphatase, osteocalcin and pyridinoline). The tibias were dissected to estimate MMP-9 and NF-kB gene expression, OPG, RANKL levels and for histological examination. Induction of osteoporosis resulted in a significant elevation in BTM, inflammatory markers and dyslipidemia. MMP-9 was significantly elevated and positively correlated with BTM, inflammation and dyslipidemia markers. Carvedilol and alendronate exerted a bone preservative role and attenuated dyslipidaemia and inflammation in accordance with their respective effect on MMP-9.

High-Throughput Absolute Quantification Sequencing Revealed Osteoporosis-Related Gut Microbiota Alterations in Han Chinese Elderly

Objective

Accumulative evidence suggests that gut microbiota play an important role in bone remodeling and hence bone health maintenance. This study aimed to explore the association of gut microbiota with the risk of osteoporosis and to identify potential disease-related taxa, which may be promising targets in osteoporosis prevention and treatment in the future.

Methods

Absolute quantification 16S ribosomal RNA gene sequencing was used to detect absolute and relative abundances of gut microbiota in 44 patients with osteoporosis and 64 controls. In combination with one of our previous studies, a total of 175 samples were involved in the relative abundance analysis.

Results

Compared with the controls, the patients with osteoporosis had higher absolute and relative abundances of Bacteroidetes phylum, and Bacteroides and Eisenbergiella genera. The absolute abundances of Clostridium_XlVa, Coprococcus, Lactobacillus, and Eggerthella genera increased, and that of the Veillonella genus decreased in the osteoporosis group. As for relative abundance, that of the Parabacteroides and Flavonifractor genera increased, whereas that of the Raoultella genus decreased in the osteoporosis group. Controlling for potential confounders, the associations of Clostridium_XlVa, Coprococcus, and Veillonella genera with the risk of osteoporosis did not maintain significance. Ridge regression analysis suggested that Bacteroides is associated with reduced bone mineral density (BMD) and T-score at lumbar spines, and Anaerovorax is associated with increased BMD at the femoral neck. Functional predictions revealed that 10 Kyoto Encyclopedia of Genes and Genomes pathways were enriched in the osteoporosis group.

Conclusions

Gut microbiota compositions may contribute to the risk of osteoporosis. Several specific taxa and functional pathways are identified to associate with reduced bone density, thus providing epidemiologic evidence for the potential role of aberrant gut microbiota in osteoporosis pathogenesis.

The Effects of Calcium, Magnesium, Phosphorus, Fluoride, and Lead on Bone Tissue

Bones are metabolically active organs. Their reconstruction is crucial for the proper functioning of the skeletal system during bone growth and remodeling, fracture healing, and maintaining calcium-phosphorus homeostasis. The bone metabolism and tissue properties are influenced by trace elements that may act either indirectly through the regulation of macromineral metabolism, or directly by affecting osteoblast and osteoclast proliferation or activity, or through becoming part of the bone mineral matrix. This study analyzes the skeletal impact of macroelements (calcium, magnesium, phosphorus), microelements (fluorine), and heavy metals (lead), and discusses the concentration of each of these elements in the various bone tissues.

Identification of Potential Therapeutic Targets and Molecular Regulatory Mechanisms for Osteoporosis by Bioinformatics Methods

BACKGROUND

Osteoporosis is characterized by low bone mass, deterioration of bone tissue structure, and susceptibility to fracture. New and more suitable therapeutic targets need to be discovered.

METHODS

We collected osteoporosis-related datasets (GSE56815, GSE99624, and GSE63446). The methylation markers were obtained by differential analysis. Degree, DMNC, MCC, and MNC plug-ins were used to screen the important methylation markers in PPI network, then enrichment analysis was performed. ROC curve was used to evaluate the diagnostic effect of osteoporosis. In addition, we evaluated the difference in immune cell infiltration between osteoporotic patients and control by ssGSEA. Finally, differential miRNAs in osteoporosis were used to predict the regulators of key methylation markers.

RESULTS

A total of 2351 differentially expressed genes and 5246 differentially methylated positions were obtained between osteoporotic patients and controls. We identified 19 methylation markers by PPI network. They were mainly involved in biological functions and signaling pathways such as apoptosis and immune inflammation. HIST1H3G, MAP3K5, NOP2, OXA1L, and ZFPM2 with higher AUC values were considered key methylation markers. There were significant differences in immune cell infiltration between osteoporotic patients and controls, especially dendritic cells and natural killer cells. The correlation between MAP3K5 and immune cells was high, and its differential expression was also validated by other two datasets. In addition, NOP2 was predicted to be regulated by differentially expressed hsa-miR-3130-5p.

CONCLUSION

Our efforts aim to provide new methylation markers as therapeutic targets for osteoporosis to better treat osteoporosis in the future.

Transgenic inhibition of interleukin-6 trans-signaling does not prevent skeletal pathologies in mucolipidosis type II mice

Severe skeletal alterations are common symptoms in patients with mucolipidosis type II (MLII), a rare lysosomal storage disorder of childhood. We have previously reported that progressive bone loss in a mouse model for MLII is caused by an increased number of bone-resorbing osteoclasts, which is accompanied by elevated expression of the cytokine interleukin-6 (IL-6) in the bone microenvironment. In the present study we addressed the question, if pharmacological blockade of IL-6 can prevent the low bone mass phenotype of MLII mice. Since the cellular IL-6 response can be mediated by either the membrane-bound (classic signaling) or the soluble IL-6 receptor (trans-signaling), we first performed cell culture assays and found that both pathways can increase osteoclastogenesis. We then crossed MLII mice with transgenic mice expressing the recombinant soluble fusion protein sgp130Fc, which represents a natural inhibitor of IL-6 trans-signaling. By undecalcified histology and bone-specific histomorphometry we found that high circulating sgp130Fc levels do not affect skeletal growth or remodeling in wild-type mice. Most importantly, blockade of IL-6 trans-signaling did neither reduce osteoclastogenesis, nor increase bone mass in MLII mice. Therefore, our data clearly demonstrate that the bone phenotype of MLII mice cannot be corrected by blocking the IL-6 trans-signaling.

Role of sirtuins in bone biology: Potential implications for novel therapeutic strategies for osteoporosis

The decline in bone mass and bone strength and musculoskeletal problems associated with aging constitute a major challenge for affected individuals and the healthcare system globally. Sirtuins 1-7 (SIRT1-SIRT7) are a family of nicotinamide adenine dinucleotide-dependent deacetylases with remarkable abilities to promote longevity and counteract age-related diseases. Sirtuin knockout and transgenic models have provided novel insights into the function and signaling of these proteins in bone homeostasis. Studies have revealed that sirtuins play a critical role in normal skeletal development and homeostasis through their direct action on bone cells and that their dysregulation might contribute to different bone diseases. Preclinical studies have demonstrated that mice treated with sirtuin agonists show protection against age-related, postmenopausal, and immobilization-induced osteoporosis. These findings suggest that sirtuins could be potential targets for the modulation of the imbalance in bone remodeling and treatment of osteoporosis and other bone disorders. The aim of this review was to provide a comprehensive updated review of the current knowledge on sirtuin biology, focusing specifically on their roles in bone homeostasis and osteoporosis, and potential pharmacological interventions targeting sirtuins for the treatment of osteoporosis.

Macrophage Polarization and Osteoporosis: A Review

Over 200 million people suffer from osteoporosis worldwide. Individuals with osteoporosis have increased rates of bone resorption while simultaneously having impaired osteogenesis. Most current treatments for osteoporosis focus on anti-resorptive methods to prevent further bone loss. However, it is important to identify safe and cost-efficient treatments that not only inhibit bone resorption, but also stimulate anabolic mechanisms to upregulate osteogenesis. Recent data suggest that macrophage polarization may contribute to osteoblast differentiation and increased osteogenesis as well as bone mineralization. Macrophages exist in two major polarization states, classically activated macrophages (M1) and alternatively activated macrophage (M2) macrophages. The polarization state of macrophages is dependent on molecules in the microenvironment including several cytokines and chemokines. Mechanistically, M2 macrophages secrete osteogenic factors that stimulate the differentiation and activation of pre-osteoblastic cells, such as mesenchymal stem cells (MSC’s), and subsequently increase bone mineralization. In this review, we cover the mechanisms by which M2 macrophages contribute to osteogenesis and postulate the hypothesis that regulating macrophage polarization states may be a potential treatment for the treatment of osteoporosis.

Interleukin-6 May Not Affect Bone Resorption Marker CTX or Bone Formation Marker P1NP in Humans

Context

Interleukin 6 (IL-6) contributes to bone remodeling in preclinical studies. Clinical trials investigating the role of IL-6 in bone remodeling are limited.

Objective

To investigate if IL-6 regulates bone remodeling in humans.

Design

Plasma concentrations of the bone resorption marker carboxy-terminal type I collagen crosslinks (CTX) and of the bone formation marker procollagen type 1 N-terminal propeptide (P1NP) were measured during a mixed-meal tolerance test (MMTT) in 3 placebo-controlled human studies.

Participants

Five healthy individuals participated in study 1; 52 obese individuals, in study 2; and 10 healthy individuals, in study 3.

Interventions

Study 1 was a single-blinded crossover study consisting of a 1-h infusion of saline (placebo) or the IL-6 receptor antibody tocilizumab followed by an exercise bout. Study 2 was a randomized, double-blinded 12-week exercise training intervention study. Participants received infusions of saline or tocilizumab. Study 3 was a randomized, double-blinded, crossover study consisting of 30 min infusion of saline or IL-6.

Main outcomes measures

Effect of IL-6 on CTX levels.

Results

CTX was significantly (P < 0.01) decreased during MMTTs in all 3 studies. Treatment with tocilizumab did not affect exercise or meal induced changes in plasma CTX or P1NP concentrations acutely (study 1) or after a 12-week treatment period (study 2). Exogenous IL-6 had no effect on CTX or P1NP plasma concentrations (study 3).

Conclusions

IL-6 may not regulate bone remodeling in humans.

Endogenous estradiol and inflammation biomarkers: potential interacting mechanisms of obesity-related disease

PURPOSE

Disentangling the effects of endogenous estrogens and inflammation on obesity-related diseases requires a clearer understanding of how the two biological mechanisms relate to each other.

METHODS

We studied 155 healthy postmenopausal women not taking menopausal hormone therapy enrolled in the Prostate Lung Colorectal and Ovarian (PLCO) screening cancer trial. From a baseline blood draw, we measured endogenous estradiol and 69 inflammation biomarkers: cytokines, chemokines, adipokines, angiogenic factors, growth factors, acute phase proteins, and soluble receptors. We evaluated the estradiol-inflammation relationship by assessing associations across different models (linear, ordinal logistic, and binary logistic) using a variety of estradiol classifications. We additionally investigated the estradiol-inflammation relationship stratified by baseline obesity status (BMI < 30 stratum and BMI > 30 stratum).

RESULTS

Associations of estradiol with 7 inflammation biomarkers met p < 0.05 statistical significance in linear and ordinal models: C-reactive protein (CRP), adiponectin, chemokine (C-X-C motif) ligand-6, thymus activation-regulated chemokine, eosinophil chemotactic protein, plasminogen activator inhibitor-1, and serum amyloid A. The positive association between estradiol and CRP was robust to model changes. Each standard deviation increase in endogenous estradiol doubled a woman's odds of having CRP levels higher than the study median (odds ratio 2.29; 95% confidence interval 1.28, 4.09). Estradiol was consistently inversely associated with adiponectin. Other estradiol-inflammation biomarker associations were not robust to model changes.

CONCLUSIONS

Endogenous estradiol appears to be associated with CRP and adiponectin; the evidence is limited for other inflammation biomarkers.

IL-33/IL-31 Axis in Osteoporosis

The study of the immunoskeletal interface has led to the discovery of numerous cytokines involved in the regulation of bone remodeling, providing valuable information on the pathogenesis of osteoporosis. The role of inflammatory cytokines of the Th1 and Th17 profile in osteoporosis is well known. Here we focus on two newly discovered Th2 cytokines, IL-31 and IL-33, whose implications in osteoporosis are recently emerging. Clinical and experimental observations suggest an important role of the IL-33/IL-31 axis in osteoporosis. IL-33 induces IL-31 secretion by Th2 cells and inhibits RANKL-dependent osteoclastogenesis, thus counteracting bone loss. IL-31 influences Th1/Th17 osteoclastogenetic inflammation and limits Th2 osteoprotective processes, thus favoring osteoporosis. Better knowledge of the role of IL-31 and IL-33 and their receptor complexes in osteoporosis could provide an interesting perspective for the development of new and more effective therapies, possibly with less side effects.

Cytokines in Inflammatory Disease

This review aims to briefly discuss a short list of a broad variety of inflammatory cytokines. Numerous studies have implicated that inflammatory cytokines exert important effects with regard to various inflammatory diseases, yet the reports on their specific roles are not always consistent. They can be used as biomarkers to indicate or monitor disease or its progress, and also may serve as clinically applicable parameters for therapies. Yet, their precise role is not always clearly defined. Thus, in this review, we focus on the existing literature dealing with the biology of cytokines interleukin (IL)-6, IL-1, IL-33, tumor necrosis factor-alpha (TNF-α), IL-10, and IL-8. We will briefly focus on the correlations and role of these inflammatory mediators in the genesis of inflammatory impacts (e.g., shock, trauma, immune dysregulation, osteoporosis, and/or critical illness).

Bench-to-bedside strategies for osteoporotic fracture: From osteoimmunology to mechanosensation

Osteoporosis is characterized by a decrease in bone mass and strength, rendering people prone to osteoporotic fractures caused by low-energy forces. The primary treatment strategy for osteoporotic fractures is surgery; however, the compromised and comminuted bones in osteoporotic fracture sites are not conducive to optimum reduction and rigid fixation. In addition, these patients always exhibit accompanying aging-related disorders, including high inflammatory status, decreased mechanical loading and abnormal skeletal metabolism, which are disadvantages for fracture healing around sites that have undergone orthopedic procedures. Since the incidence of osteoporosis is expected to increase worldwide, orthopedic surgeons should pay more attention to comprehensive strategies for improving the poor prognosis of osteoporotic fractures. Herein, we highlight the molecular basis of osteoimmunology and bone mechanosensation in different healing phases of elderly osteoporotic fractures, guiding perioperative management to alleviate the unfavorable effects of insufficient mechanical loading, high inflammatory levels and pathogen infection. The well-informed pharmacologic and surgical intervention, including treatment with anti-inflammatory drugs and sufficient application of antibiotics, as well as bench-to-bedside strategies for bone augmentation and hardware selection, should be made according to a comprehensive understanding of bone biomechanical properties in addition to the remodeling status of osteoporotic bones, which is necessary for creating proper biological and mechanical environments for bone union and remodeling. Multidisciplinary collaboration will facilitate the improvement of overall osteoporotic care and reduction of secondary fracture incidence.

Association between dietary inflammatory index and bone density in lactating women at 6 months postpartum: a longitudinal study

BACKGROUND

Chronic inflammation contributes to the risk of osteoporosis and fracture. Dietary Inflammatory Index (DII), a novel method appraising the inflammatory potential of diet, has been utilized to examine the association between diet and bone health among postmenopausal women or the elderly. However, its relationship with bone density (BD) in lactating women has not been studied.

METHODS

The prospective study was conducted to assess the possible association between DII and maternal BD during lactation. We enrolled 150 lactating women in the cohort. Participants were measured ultrasonic BD as baseline values at 1 month postpartum. After five-month follow up, the participants' BD were measured again. DII scores were calculated from semi-quantitative food frequency questionnaires (FFQ) and divided into tertiles. We compared the differences in the changes of BD at 6 months postpartum without or with adjustment for potential covariates across the tertiles.

RESULTS

The women in Q1 of DII scores had less bone mass loss than those in Q2 and Q3 without adjustment for any covariates (p < 0.01); after adjusting demographic characteristics such as BMI (kg/m2) at 6 months postpartum, educational level, metabolic equivalent (MET), daily energy intake (kcal/d), we found that participants in the highest tertile of DII scores had much more bone loss than those in the lowest tertile (p = 0.038). However, in the test for trend, no significant association between DII and the changes of maternal BD at 6 months postpartum was observed.

CONCLUSIONS

Chinese lactating women with higher DII scores have more bone mass loss; however significant differences and trends are attenuated and/or disappear depending on covariates and confounders that are taken into account in statistical analysis. The further study should be conducted in larger population to explore whether the significant association between DII and BD exists in Chinese lactating women.

Impact of interleukin-6 gene polymorphisms and its interaction with obesity on osteoporosis risk in Chinese postmenopausal women

AIMS

To investigate the association of four single-nucleotide polymorphisms (SNPs) of the IL-6 gene with osteoporosis (OST) susceptibility.

METHODS

PCR restriction fragment length polymorphism (PCR-RFLP) was carried out for SNPs detection. Generalized multifactor dimensionality reduction (GMDR) model and logistic regression model were used to examine the interaction between SNP and obesity on OST.

RESULTS

Logistic regression model revealed that G allele of rs1800796 and the T allele of rs2069849 were associated with increased OST risk, compared to those with wild genotype. However, no significant correlations were found when analyzing the association of rs1800795 and rs1554606 with OST risk. GMDR analysis suggested that the interaction model composed of the rs1800796 and obesity was the best model with statistical significance (P value from sign test [Psign] = 0.012), indicating a potential gene-environment interaction between rs1800796 and obesity. Overall, the two-locus models had a cross-validation consistency of 10/10 and had the testing accuracy of 0.641. We also conducted stratified analysis for rs1800796 genotype and obesity, and found that obese subjects with CG or GG genotype have the highest OST risk, compared to subjects with CC genotype, and normal BMI OR (95% CI) = 2.21 (1.52-3.49), after adjustment for age, smoke, and alcohol consumption status.

CONCLUSIONS

Our results suggested that the C allele of rs1800796 and the C allele of rs2069849 of IL-6 gene interaction between rs1800796 and abdominal obesity were all associated with increased OST risk.

The Impact of Thyme and Rosemary on Prevention of Osteoporosis in Rats

Osteoporosis poses an important public health problem which affects millions of people worldwide. There is a direct link between calcium deficiency in diet and induction of osteoporosis and bone loss. The current study was conducted to evaluate the protective effect of thyme (Thymus vulgaris L.) and rosemary (Rosmarinus officinalis L.) against osteoporosis in rats with low calcium intake. Essential oils of rosemary and thyme were analyzed. The experiment was carried out on growing male Sprague-Dawley rats; the experimental animals were divided into 5 groups: 1, control negative was fed standard balanced diet; 2, control positive was fed balanced diet with low calcium level (L Ca) (Ca 0.1% w/w); 3, (L Ca) + thyme powder (5% w/w); 4, (L Ca) + rosemary powder (5% w/w); 5, (L Ca) + orally administration with CaCO3 (27 mg/kg body weight). Blood samples were collected for different biochemical analyses in plasma (calcium (Ca), phosphorus (P), magnesium (Mg), tumor necrosis factor-alpha (TNF-α), C-reactive protein (CRP), malondialdehyde (MDA), parathyroid hormone (PTH), C-terminal telopeptide (CTX), and 1,25-(OH)2-vitamin D3). Femur mass, length, and bone mineral density (BMD) were recorded, and histopathological studies for femurs were examined. Low-calcium diet induced osteoporotic changes in positive control rats (decrease in Ca, vitamin D3, and BMD and increase in CTX, PTH, TNF-α, CRP, and MDA). Supplementation with thyme and rosemary inhibited significantly the development of bone loss, increased Ca and vitamin D3 in plasma, improved BMD, and also prevented the inflammation and oxidative stress (improved TNF-α, CRP and MDA) compared to the positive control. The histopathological examination of treated groups showed an improvement in bone histology and protection against bone loss. However, thyme powder showed more effective impact than rosemary. Our study demonstrates that thyme and rosemary effectively mitigated calcium deficiency-induced bone loss and maybe considered as promising candidates for preventing bone resorption and osteoporosis.

Anti-inflammatory effects of a novel compound, MPQP, through the inhibition of IRAK1 signaling pathways in LPS-stimulated RAW 264.7 macrophages

Small-molecule inhibitors are widely used to treat a variety of inflammatory diseases. In this study, we found a novel anti-inflammatory compound, 1-[(2R,4S)-2-methyl-4-(phenylamino)-1,2,3,4-tetrahydroquinolin-1-yl]prop-2-en-1-one (MPQP). It showed strong anti-inflammatory effects in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. These effects were exerted through the inhibition of the production of NO and pro-inflammatory cytokines, such as interleukin (IL)-6, IL-1β, and tumor necrosis factor-α (TNF-α). Furthermore, MPQP decreased the expression levels of inducible NO synthase (iNOS) and cyclooxygenase 2 (COX-2). Additionally, it mediated the inhibition of the phosphorylation of p38, c-Jun N-terminal kinase (JNK), the inhibitor of κBα (IκBα), and their upstream kinases, IκB kinase (IKK) α/β, mitogen-activated protein kinase kinase (MKK) 3/6, and MKK4. Furthermore, the expression of IL-1 receptor-associated kinase 1 (IRAK1) that regulates NF-κB, p38, and the JNK signaling pathways, was also increased by MPQP. These results indicate that MPQP regulates the IRAK1-mediated inflammatory signaling pathways by targeting IRAK1 or its upstream factors.

Relationships between markers of inflammation and bone density: findings from the Hertfordshire Cohort Study

Among 365 Hertfordshire Cohort Study participants (aged 59-71 years at baseline), higher adiponectin and adiponectin to leptin ratios were associated with lower baseline lumbar spine and femoral neck bone mineral density (BMD). Lower IL-10 was associated with accelerated decline in lumbar spine BMD. This suggests that bone health can be influenced by changes in immune phenotype and alterations in adipokine homeostasis.

INTRODUCTION

The aim of this study was to examine the association between indices of inflammation and BMD in a population-based cohort of older adults in the UK.

METHODS

Analyses were based on a sample of 194 men and 171 women of the Hertfordshire Cohort Study (community-living, older adults). Dual energy X-ray absorptiometry (DXA) was performed at the lumbar spine and proximal femur at baseline and repeated at a median of 4.5 years (inter-quartile range 3.6 to 5.2). Inflammatory markers (CRP, TNF, IL-1β, IL-6, IL-8, IL-10, adiponectin and leptin) were ascertained at baseline using enzyme-linked immunosorbent assay (ELISA) techniques and Bio-Plex Pro Assays. Gender-adjusted linear regression was used to examine the associations between markers of inflammation and outcomes with and without adjustment for anthropometric and lifestyle factors.

RESULTS

The mean (SD) ages at baseline were 64.4 (2.5) and 66.5 (2.7) years for men and women respectively. Higher levels of adiponectin and adiponectin to leptin ratios were each associated with lower baseline lumbar spine and femoral neck BMD in gender-adjusted (p < 0.01) and fully adjusted (p < 0.05) analyses. Lower levels of IL-10 and TNF were each associated with accelerated decline in lumbar spine BMD in both gender-adjusted (p ≤ 0.05) and fully adjusted (p < 0.05) analyses.

CONCLUSIONS

In a cohort of older adults, high levels of adiponectin and adiponectin to leptin ratios were both associated with lower BMD at the lumbar spine and femoral neck at baseline, and lower IL-10 was associated with accelerated decline in BMD at the lumbar spine. This adds weight to the theory that bone health can be influenced by changes in immune phenotype and alterations in adipokine homeostasis.

Effects of vitamin B12, folate, uric acid, and serum biomarkers of inflammation on bone mineral density in postmenopausal women

Introduction

Despite the accumulating evidence suggesting a possible relationship between femur and lumbar bone mineral density (BMD) and serum uric acid (UA), it is unclear whether alterations in UA levels reflect any underlying subclinical inflammatory conditions in postmenopausal osteoporosis. In addition, the mechanistic link between osteoporosis and dietary factors including vitamin B₁₂ and folate in postmenopausal women is still obscure. The aim of the present study is to investigate the association between serum vitamin B₁₂, folate, UA, and subclinical inflammatory markers and BMD measurements in postmenopausal women.

Material and methods

One hundred and eighty-four postmenopausal women were recruited for the present study. Clinical data, as well as serum vitamin B₁₂, folate, UA, conventional inflammatory markers, and other related biochemical markers, were assessed for each subject. Bone mineral density measurements of proximal femur and lumbar spine were taken using dual-energy X-ray absorptiometry. Correlation analysis was performed between serum vitamin B₁₂, folate, UA and other biochemical and metabolic parameters.

Results

Although no association was found between serum inflammatory markers, vitamin B₁₂ and folate levels with femur neck and lumbar spine BMD measurements, elevated UA levels were observed in subjects with normal BMD values. Higher BMD values were obtained in higher UA tertiles. UA (p < 0.001) and BMI (p = 0.003) were found to be correlated with femur neck BMD measurements.

Conclusions

The femoral and lumbar BMD measurements were associated with serum UA levels. Higher serum UA levels were found to have a protective effect on postmenopausal osteoporosis irrespective of inflammation and dietary factors.

Association between Bone Mineral Density and Albuminuria: Cross-Sectional Analysis of Data from the 2011 Korea National Health and Nutrition Examination Survey V-2

BACKGROUND

Albuminuria is known to be independently associated with progression of renal and cardiovascular disease. However, little is known regarding the exact relationship between albuminuria and bone mineral density (BMD). The aim of this population-based study conducted in Korea was to identify the association between albuminuria and BMD.

METHODS

We performed a cross-sectional analysis of data from the Korea National Health and Nutrition Examination Survey (KNHANES V-2) 2011. BMD was measured for total hip (TH), femur neck (FN), and lumbar spine (LS). Analysis of covariance was used to compare BMD levels between the groups at the TH, FN, and LS sites, after adjusting for age. Separate analyses were performed according to sex; women were divided into two groups according to menopausal status and each group was subdivided into three according to urine albumin-to-creatinine ratio (level 1, <30 mg/g; level 2, 30 to 299 mg/g; level 3, ≥300 mg/g).

RESULTS

Data on a total of 1,831 adults (857 men and 974 women) were analyzed. In postmenopausal women, after adjusting for age, BMD of TH tended to decrease as levels of albuminuria increased (0.767±0.117, 0.757±0.129, 0.752±0.118, respectively; P=0.040). However, there was no significant difference in BMD according to albuminuria level in premenopausal women and men.

CONCLUSION

Level of albuminuria was closely related with BMD of TH in postmenopausal women, after adjusting for age, but there was no significant relationship between albuminuria and BMD in premenopausal women and men.

Cross-talk between primary osteocytes and bone marrow macrophages for osteoclastogenesis upon collagen treatment

Homeostasis of osteoclast formation from bone marrow macrophages (BMM) is regulated by paracrine signals of the neighbourhood bone cells particularly mesenchymal stem cells (MSC), osteoblasts and osteocytes (OC). Besides paracrine cues, collagen and glycosaminoglycan are involved in controlling bone homeostasis. Towards this approach, different molecular weight collagens were reacted with MSC, OC and BMM to understand the bone homeostasis activity of collagen. The up-regulating effect of collagens on osteogenic cell growth was confirmed by the presence of mineralized nodules in the osteoblastogenic lineage cells and increased osteogenic stimulatory gene expression. The decreased BMM-derived TRAP+ osteoclasts number and osteoclastogenic regulatory gene expression of OC could demonstrate the exploitive osteoclastogenic activity of collagens. Osteoclastogenesis from BMM was triggered by paracrine cues of OC in some extend, but it was down-regulated by collagen. Overall, the effect of collagen on osteoclastogenesis and osteoblastogenesis may depend on the molecular weight of collagens, and collagen suppresses osteoclastogenesis, at least in part by downregulating the secretion of cytokines in OC.

Aerobic but not Resistance Exercise Can Induce Inflammatory Pathways via Toll-Like 2 and 4: a Systematic Review

BACKGROUND

Only a few studies have addressed the relationship between toll-like receptors 2 and 4 (TLR2 and TLR4) and the production of local and systemic cytokines in response to physical exercise, and they have produced conflicting results. We aimed to determine whether acute and chronic exercise outcomes are associated with changes in TLR2 and TLR4 expression and signaling and if so, the mechanisms that connect them.

METHODS

PubMed database were consulted. This systematic review selected 39 articles, 26 involving humans and 13 based on rodents.

RESULTS

In acute resistance exercise studies, 75% reported a decrease in TLR4 or TLR2 expression and 25% did not find differences. For chronic resistance exercise studies, 67% reported a reduction of expression and 33% did not find differences. Studies of both types reported reductions in pro-inflammatory cytokines. In acute aerobic exercise studies, 40% revealed a decline in the expression of the receptors, 7% reported no significant difference, 40% showed an increase, and 13% did not evaluate their expression. Fifty-eight percent of studies of chronic aerobic exercise revealed a reduction in expression, 17% did not find a difference, and 25% reported increases; they also suggested that the expression of the receptors might be correlated with that of inflammatory cytokines. In studies on combined exercise, 50% reported a decline in receptors expression and 50% did not find a difference.

CONCLUSIONS

The majority of the articles (54%) link different types of exercise to a decline in TLR4 and TLR2 expression. However, aerobic exercise may induce inflammations through its influence on these receptor pathways. Higher levels of inflammation were seen in acute sessions (40%) than regular sessions (25%).

Inflammation and bone mineral density: A Mendelian randomization study

Osteoporosis is a common age-related disorder leading to an increase in osteoporotic fractures and resulting in significant suffering and disability. Inflammation may contribute to osteoporosis, as it does to many other chronic diseases. We examined whether inflammation is etiologically relevant to osteoporosis, assessed from bone mineral density (BMD), as a new potential target of intervention, or whether it is a symptom/biomarker of osteoporosis. We obtained genetic predictors of inflammatory markers from genome-wide association studies and applied them to a large genome wide association study of BMD. Using two-sample Mendelian randomization, we obtained unconfounded estimates of the effect of high-sensitivity C-reactive protein (hsCRP) on BMD at the forearm, femoral neck, and lumbar spine. After removing potentially pleiotropic single nucleotide polymorphisms (SNPs) possibly acting via obesity-related traits, hsCRP, based on 16 SNPs from genes including CRP, was not associated with BMD. A causal relation of hsCRP with lower BMD was not evident in this study.

Bone Density Loss Is Associated With Blood Cell Counts

Hematopoiesis depends on a supportive microenvironment. Preclinical studies in mice have demonstrated that osteoblasts influence the development of blood cells, particularly erythrocytes, B lymphocytes, and neutrophils. However, it is unknown whether osteoblast numbers or function impact blood cell counts in humans. We tested the hypothesis that men with low BMD or greater BMD loss have decreased circulating erythrocytes and lymphocytes and increased myeloid cells. We performed a cross-sectional analysis and prospective analysis in the Osteoporotic Fractures in Men (MrOS) study, a multisite longitudinal cohort study. A total of 2571 community-dwelling men (≥65 years) who were able to walk without assistance, did not have a hip replacement or fracture, and had complete blood counts (CBCs) at the third study visit were analyzed. Multivariable (MV)-adjusted logistic regression estimated odds of white blood cell (WBC) subtypes (highest and lowest quintile versus middle), and anemia (clinically defined) associated with BMD by DXA scan (at visit 3), annualized percent BMD change (baseline to visit 3), and high BMD loss (>0.5%/year, from baseline to visit 3) at the femoral neck (FN) and total hip (TH). MV-adjusted models included age, BMI, cancer history, smoking status, alcohol intake, corticosteroid use, self-reported health, thiazide use, and physical activity. At visit 3 greater TH BMD loss (per 1 SD) was associated with increased odds of anemia, high neutrophils, and low lymphocytes. Annualized BMD loss of >0.5% was associated with increased odds of anemia, high neutrophils, and low lymphocytes. Similar results were observed for FN BMD regarding anemia and lymphocytes. We conclude that community-dwelling older men with declining hip BMD over about 7 years had increased risks of anemia, lower lymphocyte count, and higher neutrophil count, consistent with preclinical studies. Bone health and hematopoiesis may have greater interdependency than previously recognized. © 2016 American Society for Bone and Mineral Research.

Inflammation as a contributing factor among postmenopausal Saudi women with osteoporosis

Postmenopausal osteoporosis is an important metabolic bone disease characterized by rapid bone loss occurring in the postmenopausal period. Recently, the most prevalent form of clinically significant osteopenia and osteoporosis involves various inflammatory conditions. The aim of the study is to evaluate the association between proinflammatory markers (interleukin [IL]-1β, IL-6, TNF-α) with bone turnover markers (BTMs) in postmenopausal Saudi women with and without osteoporosis. A total of 200 postmenopausal Saudi women ≥50 years old, 100 with osteoporosis and 100 without osteoporosis (control) were recruited under the supervision of qualified physicians in King Salman Hospital and King Fahd Medical City, Riyadh, Saudi Arabia. Serum tumor necrosis factor alpha (TNF-α), IL-1, IL-4, IL-6, and parathyroid hormone (PTH) were determined using Luminex xMAP technology. N-telopeptides of collagen type I (NTx) was assessed using ELISA, 25(OH) vitamin D and osteocalcin were determined using electrochemiluminescence, serum calcium and inorganic phosphate (Pi) were measured by a chemical analyzer. Serum IL-1β, IL-6, NTx, and PTH levels in women with osteoporosis were significantly higher than controls. Although IL-4 and osteocalcin were significantly lower than controls. IL-1β and TNF-α were positively associated with NTx in osteoporosis women. TNF-α, IL-6, and TNF-α were positively correlated with IL-lβ in both groups. A significant negative correlation between osteocalcin and IL-1β in healthy women and women with osteoporosis were observed. Findings of the present study implicate a role for cytokine pattern-mediated inflammation in patients with osteoporosis.

Osteoporosis and Periodontitis

Osteoporosis and periodontitis are both diseases characterized by bone resorption. Osteoporosis features systemic degenerative bone loss that leads to loss of skeletal cancellous microstructure and subsequent fracture, whereas periodontitis involves local inflammatory bone loss, following an infectious breach of the alveolar cortical bone, and it may result in tooth loss. Most cross-sectional studies have confirmed the association of osteoporosis and periodontitis primarily on radiographic measurements and to a lesser degree on clinical parameters. Multiple shared risk factors include age, genetics, hormonal change, smoking, as well as calcium and vitamin D deficiency. Both diseases could also be risk factors for each other and have a mutual impact that requires concomitant management. Suggested mechanisms underlying the linkage are disruption of the homeostasis concerning bone remodeling, hormonal balance, and inflammation resolution. A mutual interventional approach is emerging with complex treatment interactions. Prevention and management of both diseases require interdisciplinary approaches and warrants future well-controlled longitudinal and interventional studies for evidence-based clinical guidelines.

Inflammatory Markers and the Risk of Hip and Vertebral Fractures in Men: the Osteoporotic Fractures in Men (MrOS)

Cytokines play major roles in regulating bone remodeling, but their relationship to incident fractures in older men is uncertain. We tested the hypothesis that men with higher concentrations of pro-inflammatory markers have a higher risk of fracture. We used a case-cohort design and measured inflammatory markers in a random sample of 961 men and in men with incident fractures including 120 clinical vertebral, 117 hip, and 577 non-spine fractures; average follow-up 6.13 years (7.88 years for vertebral fractures). We measured interleukin (IL)-6, C-reactive protein (CRP), tumor necrosis factor alpha (TNFα), soluble receptors (SR) of IL-6 (IL-6SR) and TNF (TNFαSR1 and TNFαSR2), and IL-10. The risk of non-spine, hip, and clinical vertebral fracture was compared across quartiles (Q) of inflammatory markers using Cox proportional hazard models with tests for linear trend. In multivariable-adjusted models, men with the highest (Q4) TNFa cytokine concentrations and their receptors had a 2.0-4.2-fold higher risk of hip and clinical vertebral fracture than men with the lowest (Q1). Results were similar for all non-spine fractures, but associations were smaller. There was no association between CRP and IL-6SR and fracture. Men in the highest Q of IL-10 had a 49% lower risk of vertebral fracture compared with men in Q1. Among men with ≥3 inflammatory markers in the highest Q, the hazard ratio (HR) for hip fractures was 2.03 (95% confidence interval [CI] 1.11-3.71) and for vertebral fracture 3.06 (1.66-5.63). The HRs for hip fracture were attenuated by 27%, 27%, and 15%, respectively, after adjusting for appendicular lean mass (ALM), disability, and bone density, suggesting mediating roles. ALM also attenuated the HR for vertebral fractures by 10%. There was no association between inflammation and rate of hip BMD loss. We conclude that inflammation may play an important role in the etiology of fractures in older men. © 2016 American Society for Bone and Mineral Research.

The association between interleukin 6 -174 G/C gene polymorphism and the risk of osteoporosis: A meta-analysis

Objectives

This study aimed to investigate the association between the IL6 −174 G/C gene polymorphism and the risk of osteoporosis by performing a meta-analysis.

Methods

Published literature from PubMed and Embase databases was searched for eligible publications. The following information was extracted from each study: Name of first author, year of publication, country of origin, sample size of cases and controls, and size of each allele. The combined odds ratio (ORs) and 95% confidence intervals (95%CIs) for the association between the IL6 −174 G/C gene polymorphism and the risk of osteoporosis were assessed using a random or fixed effects model. A comprehensive meta-analysis (CMA) 2.0 was used to analyse the data.

Results

Twelve studies (4923 cases/3431 controls) were included in this meta-analysis. The results indicated that IL6 −174 G/C gene polymorphism was associated with an increased (G vs C, OR 95%CI = 1.29 [1.03–1.62], p = 0.029) and decreased risk of osteoporosis (C vs G, OR 95%CI = 0.77 [0.62–0.97], p = 0.029; CC vs GG + GC, OR 95%CI = 0.58 [0.39–0.88], p = 0.010).

Conclusion

The IL6 −174 G/C gene polymorphism was shown to be positively correlated with osteoporosis risk.

IL-6 Contributes to the Defective Osteogenesis of Bone Marrow Stromal Cells from the Vertebral Body of the Glucocorticoid-Induced Osteoporotic Mouse

Osteoporosis is one of the most prevalent skeletal system diseases. It is characterized by a decrease in bone mass and microarchitectural changes in bone tissue that lead to an attenuation of bone resistance and susceptibility to fracture. Vertebral fracture is by far the most prevalent osteoporotic fracture. In the musculoskeletal system, osteoblasts, originated from bone marrow stromal cells (BMSC), are responsible for osteoid synthesis and mineralization. In osteoporosis, BMSC osteogenic differentiation is defective. However, to date, what leads to the defective BMSC osteogenesis in osteoporosis remains an open question. In the current study, we made attempts to answer this question. A mouse model of glucocorticoid-induced osteoporosis (GIO) was established and BMSC were isolated from vertebral body. The impairment of osteogenesis was observed in BMSC of osteoporotic vertebral body. The expression profiles of thirty-six factors, which play important roles in bone metabolisms, were compared through antibody array between normal and osteoporotic BMSC. Significantly higher secretion level of IL-6 was observed in osteoporotic BMSCs compared with normal control. We provided evidences that IL-6 over-secretion impaired osteogenesis of osteoporotic BMSC. Further, it was observed that β-catenin activity was inhibited in response to IL-6 over-secretion. More importantly, in vivo administration of IL-6 neutralizing antibody was found to be helpful to rescue the osteoporotic phenotype of mouse vertebral body. Our study provides a deeper insight into the pathophysiology of osteoporosis and identifies IL-6 as a promising target for osteoporosis therapy.

Relationship between Serum Inflammatory Marker and Bone Mineral Density in Healthy Adults

Background

Inflammatory markers have been shown to play an important role in bone remodeling. The purpose of this study was to investigate the relationship among serum C-reactive protein (CRP), adiponectin, tumor necrosis factor-alpha (TNF-α) and bone health in healthy adults.

Methods

We measured serum levels of CRP, adiponectin, TNF-α as well as lumbar spine and femoral neck bone mineral density (BMD) in 76 adults. Anthropometric measurements and nutrient intake survey of participants were carried out. The participants were divided into two groups (normal BMD group=40; 52.6%, decreased BMD group=36; 47.4%).

Results

The CRP concentration was significantly higher in the decreased BMD group. The adiponectin concentration was lower in the decreased BMD group but the difference was not significant. The TNF-α concentration was higher in the decreased BMD group, the difference was not significant. The participants in the decreased BMD group were found to have lower calcium intakes. The sodium intake of the decreased BMD group was significantly higher. The BMD in the decreased BMD group showed inverse correlations with CRP and dietary sodium intake.

Conclusions

Serum CRP and dietary sodium intake is associated with BMD. Further research is needed to confirm the potential role of inflammatory marker to modulate the effects on bone.

Changes in Bone Mineral Density After Initiation of Antiretroviral Treatment With Tenofovir Disoproxil Fumarate/Emtricitabine Plus Atazanavir/Ritonavir, Darunavir/Ritonavir, or Raltegravir

BACKGROUND

Specific antiretroviral therapy (ART) medications and the severity of human immunodeficiency virus (HIV) disease before treatment contribute to bone mineral density (BMD) loss after ART initiation.

METHODS

We compared the percentage change in BMD over 96 weeks in 328 HIV-infected, treatment-naive individuals randomized equally to tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) plus atazanavir/ritonavir (ATV/r), darunavir/ritonavir (DRV/r), or raltegravir (RAL). We also determined whether baseline levels of inflammation markers and immune activation were independently associated with BMD loss.

RESULTS

At week 96, the mean percentage changes from baseline in spine and hip BMDs were similar in the protease inhibitor (PI) arms (spine: -4.0% in the ATV/r group vs -3.6% in the DRV/r [P = .42]; hip: -3.9% in the ATV/r group vs -3.4% in the DRV/r group [P = .36]) but were greater in the combined PI arms than in the RAL arm (spine: -3.8% vs -1.8% [P < .001]; hip: -3.7% vs -2.4% [P = .005]). In multivariable analyses, higher baseline concentrations of high-sensitivity C-reactive protein, interleukin 6, and soluble CD14 were associated with greater total hip BMD loss, whereas markers of CD4(+) T-cell senescence and exhaustion (CD4(+)CD28(-)CD57(+)PD1(+)) and CD4(+) T-cell activation (CD4(+)CD38(+)HLA-DR(+)) were associated with lumbar spine BMD loss.

CONCLUSIONS

BMD losses 96 weeks after ART initiation were similar in magnitude among patients receiving PIs, ATV/r, or DRV/r but lowest among those receiving RAL. Inflammation and immune activation/senescence before ART initiation independently predicted subsequent BMD loss.

Inflammatory co-morbidities in HIV+ individuals: learning lessons from healthy ageing

Increased life expectancy due to improved efficacy of cART has uncovered an increased risk of age-related morbidities in HIV+ individuals and catalyzed significant research into mechanisms driving these diseases. HIV infection increases the risk of non-communicable diseases common in the aged, including cardiovascular disease, neurocognitive decline, non-AIDS malignancies, osteoporosis, and frailty. These observations suggest that HIV accelerates immunological ageing, and there are many immunological similarities with the aged, including shortened telomeres, accumulation of senescent T cells and altered monocyte phenotype/function. However, the most critical similarity between HIV+ individuals and the elderly, which most likely underpins the heightened risk of non-communicable diseases, is chronic inflammation and associated immune activation. Here, we review the similarities between HIV+ individuals and the aged regarding the pathogenesis of inflammatory diseases, the current evidence for mechanisms driving these processes and discuss current and potential therapeutic strategies for addressing inflammatory co-morbidity in HIV+ infection.

Association between inflammatory biomarkers and bone mineral density in a community-based cohort of men and women

OBJECTIVE

Based upon evidence in animal and in vitro studies, we tested the hypothesis that higher serum concentrations of the cytokines interleukin-6 (IL-6) and tumor necrosis factor α (TNFα) and the inflammatory marker C-reactive protein (CRP) would be inversely associated with bone mineral density (BMD) in a community-based cohort of men and women, with the strongest associations among postmenopausal women not receiving menopause hormonal therapy (MHT).

METHODS

We ascertained fasting serum concentrations of IL-6, TNFα, and CRP and measured BMD at the femoral neck, trochanter, total femur, and spine (L2-L4) using dual x-ray absorptiometry in 2,915 members of the Framingham Offspring Study (1996-2001). We used multivariable linear regression to estimate the difference (β) in BMD at each bone site associated with a 1-unit increase in log-transformed serum concentrations of IL-6, TNFα, and CRP separately for men (n = 1,293), premenopausal women (n = 231), postmenopausal women receiving MHT (n = 498), and postmenopausal women not receiving MHT (n = 893).

RESULTS

Inflammatory biomarkers were not associated with BMD in men. Among premenopausal women, there were statistically significant, modest inverse associations between IL-6 and trochanter BMD (β = -0.030, P < 0.01) and between CRP and femoral neck (β = -0.015, P = 0.05) and trochanter BMD (β = -0.014, P = 0.04). TNFα was positively associated with spine BMD (β = 0.043, P = 0.01). In postmenopausal women receiving MHT, CRP was positively associated with femoral neck BMD (β = 0.011, P = 0.04). There were no associations among postmenopausal women not receiving MHT.

CONCLUSION

The lack of consistency in our results suggests that elevated circulating concentrations of inflammatory biomarkers may not be a risk factor for low BMD.

Inflammatory markers and risk of hip fracture in older white women: the study of osteoporotic fractures

Hip fractures are the most devastating consequence of osteoporosis and impact 1 in 6 white women leading to a two- to threefold increased mortality risk in the first year. Despite evidence of inflammatory markers in the pathogenesis of osteoporosis, few studies have examined their effect on hip fracture. To determine if high levels of inflammation increase hip fracture risk and to explore mediation pathways, a case-cohort design nested in a cohort of 4709 white women from the Study of Osteoporotic Fractures was used. A random sample of 1171 women was selected as the subcohort (mean age 80.1 ± 4.2 years) plus the first 300 women with incident hip fracture. Inflammatory markers interleukin-6 (IL-6) and soluble receptors (SR) for IL-6 (IL-6 SR) and tumor necrosis factor (TNF SR1 and TNF SR2) were measured, and participants were followed for a median (interquartile range) of 6.3 (3.7, 6.9) years. In multivariable models, the hazard ratio (HR) of hip fracture for women in the highest inflammatory marker level (quartile 4) was 1.64 (95% confidence interval [CI], 1.09-2.48, p trend = 0.03) for IL-6 and 2.05 (95% CI, 1.35-3.12, p trend <0.01) for TNF SR1 when compared with women in the lowest level (quartile 1). Among women with 2 and 3-4 inflammatory markers in the highest quartile, the HR of hip fracture was 1.51 (95% CI, 1.07-2.14) and 1.42 (95% CI, 0.87-2.31) compared with women with zero to one marker(s) in the highest quartile (p trend = 0.03). After individually adjusting for seven potential mediators, cystatin-C (a biomarker of renal function) and bone mineral density (BMD) attenuated HRs among women with the highest inflammatory burden by 64% and 50%, respectively, suggesting a potential mediating role. Older white women with high inflammatory burden are at increased risk of hip fracture in part due to poor renal function and low BMD.

Association of IL-6 G-174C polymorphism with bone mineral density

Functional polymorphisms in the promoter region of interleukin-6 (IL-6) are known to be involved in bone mineral density (BMD) and the development of osteoporosis, but the reported results have been inconsistent. Using the meta-analysis approach, the present study is designed to provide a relatively comprehensive picture of the relationship between bone mineral density (BMD) or osteoporosis and polymorphisms in the promoter region of IL-6 (rs1800795 and rs1800796). The difference of bone mineral density (BMD) values between genotypes was examined by mean difference and 95 % confidence intervals (CIs). Association between IL-6 polymorphism and clinical osteoporosis was evaluated by pooled odds ratios (ORs) and 95 % CIs. A total of 13 articles with 11,499 subjects were included in the present study. For -174 (rs1800795), we found that individuals with the G/G genotype had a significantly lower BMD value than those with C/C genotype at femoral neck (0.02 g/cm(2), 95 % CI 0.00-0.03) (p = 0.04) and distal radius (0.01 g/cm(2), 95 %CI 0.01-0.01) (p < 0.0001). However, we did not find a statistically significant difference of BMD at the spine. When analysis was limited to postmenopausal women, similar results were obtained. We further found that the C/C genotype was associated with a reduced risk of osteoporosis compared to G/G genotype, and the pooled OR was 0.72 (95 % CI 0.54-0.95, p = 0.02). In addition, a significant relationship was found between G-634C (rs1800796) polymorphism and distal radius BMD (CC vs. GG: 0.02 g/cm(2), 95 % CI 0.01-0.03; GC vs. GG: 0.02 g/cm(2), 95 % CI 0.00-0.03) in the Asian population. These findings suggest that the CC genotype of IL-6 G-174C polymorphism may be associated with high BMD at femoral neck and distal radius and decreased risk of osteoporosis in the Caucasian population whereas G-634C polymorphism was associated with distal radius BMD in Asians.

Regional molecular and cellular differences in the female rabbit Achilles tendon complex: potential implications for understanding responses to loading

The aim of this study was: (i) to analyze the morphology and expression of extracellular matrix genes in six different regions of the Achilles tendon complex of intact normal rabbits; and (ii) to assess the effect of ovariohysterectomy (OVH) on the regional expression of these genes. Female New Zealand White rabbits were separated into two groups: (i) intact normal rabbits (n = 4); and (ii) OVH rabbits (n = 8). For each rabbit, the Achilles tendon complex was dissected into six regions: distal gastrocnemius (DG); distal flexor digitorum superficialis; proximal lateral gastrocnemius (PLG); proximal medial gastrocnemius; proximal flexor digitorum superficialis; and paratenon. For each of the regions, hematoxylin and eosin staining was performed for histological evaluation of intact normal rabbit tissues and mRNA levels for proteoglycans, collagens and genes associated with collagen regulation were assessed by real-time reverse transcription-quantitative polymerase chain reaction for both the intact normal and OVH rabbit tissues. The distal regions displayed a more fibrocartilaginous phenotype. For intact normal rabbits, aggrecan mRNA expression was higher in the distal regions of the Achilles tendon complex compared with the proximal regions. Collagen Type I and matrix metalloproteinase-2 expression levels were increased in the PLG compared to the DG in the intact normal rabbit tissues. The tendons from OVH rabbits had lower gene expressions for the proteoglycans aggrecan, biglycan, decorin and versican compared with the intact normal rabbits, although the regional differences of increased aggrecan expression in distal regions compared with proximal regions persisted. The tensile and compressive forces experienced in the examined regions may be related to the regional differences found in gene expression. The lower mRNA expression of the genes examined in the OVH group confirms a potential effect of systemic estrogen on tendon.

Body composition, soluble markers of inflammation, and bone mineral density in antiretroviral therapy-naive HIV-1-infected individuals

OBJECTIVE

To determine the association among bone mineral density (BMD), inflammatory markers, and alterations in fat and lean mass in untreated HIV-infected individuals.

DESIGN

Cross-sectional analysis of antiretroviral therapy-naive persons enrolled into a randomized clinical trial.

METHODS

Dual-energy x-ray absorptiometry for BMD and lean and fat mass and a laboratory assessment were performed. Soluble biomarkers included adipocytokines (leptin and adiponectin), inflammatory markers (high-sensitivity C-reactive protein and interleukin 6), and markers related to bone metabolism [osteoprotegerin (OPG)], receptor activator of nuclear factor κB ligand. BMD at the lumbar spine, total hip, and femoral neck was expressed as a Z score (number of standard deviations away from age-, race-, and sex-matched reference population).

RESULTS

Three hundred thirty-one subjects had a median (Q1, Q3) age of 36 (28, 45) years, were 89% men, and 44% white. The prevalence of low BMD (Z score ≤ -2 at any of the 3 sites) was 10%. No associations were detected between Z scores and high-sensitivity C-reactive protein, interleukin 6, or receptor activator of nuclear factor κB ligand (P ≥ 0.1). In a linear model adjusting for age, gender, race, and total fat mass, lower lumbar spine Z scores were associated with lower total lean mass, higher serum adiponectin, and lower OPG. Results at the total hip or femoral neck were similar.

CONCLUSIONS

Among antiretroviral therapy-naive HIV-infected individuals, lower BMD was associated with lower lean mass, higher adiponectin, and lower OPG, but not HIV disease variables or any of the inflammatory markers. These findings may have implications for bone metabolism in untreated HIV, in which hypoadiponectinemia and higher OPG may mitigate bone loss.

Osteoimmunology and the influence of pro-inflammatory cytokines on osteoclasts

Bone and immune system are functionally interconnected. Immune and bone cells derive from same progenitors in the bone marrow, they share a common microenvironment and are being influenced by similar mediators. The evidence on increased bone resorption associated with inappropriate activation of T cells such as during inflammation, is well established. However, the molecular mechanisms beyond this clinical observation have begun to be intensively studied with the advancement of osteoimmunology. Now days, we have firm evidence on the influence of numerous proinflammatory cytokines on bone cells, with the majority of data focused on osteoclasts, the bone resorbing cells. It has been shown that some proinflammatory cytokines could possess osteoclastogenic and/or anti-osteoclastogenic properties and can target osteoclasts directly or via receptor activator of nuclear factor κB (RANK)/RANK ligand(RANKL)/osteoprotegerin (OPG) system. Several studies have reported opposing data regarding (anti)osteoclastogenic properties of these cytokines.

Therefore, the first part of this review is summarizing current evidence on the influence of pro-inflammatory cytokines on osteoclasts and thus on bone resorption. In the second part, the evidence on the role of pro-inflammatory cytokines in osteoporosis and osteoarthritis is reviewed to show that unravelling the mechanisms beyond such complex bone diseases, is almost impossible without considering skeletal and immune systems as an indivisible integrated system.

Surface properties and ion release from fluoride-containing bioactive glasses promote osteoblast differentiation and mineralization in vitro

Bioactive glasses (BG) are suitable for bone regeneration applications as they bond with bone and can be tailored to release therapeutic ions. Fluoride, which is widely recognized to prevent dental caries, is efficacious in promoting bone formation and preventing osteoporosis-related fractures when administered at appropriate doses. To take advantage of these properties, we created BG incorporating increasing levels of fluoride whilst holding their silicate structure constant, and tested their effects on human osteoblasts in vitro. Our results demonstrate that, whilst cell proliferation was highest on low-fluoride-containing BG, markers for differentiation and mineralization were highest on BG with the highest fluoride contents, a likely effect of a combination of surface effects and ion release. Furthermore, osteoblasts exposed to the dissolution products of fluoride-containing BG or early doses of sodium fluoride showed increased alkaline phosphatase activity, a marker for bone mineralization, suggesting that fluoride can direct osteoblast differentiation. Taken together, these results suggest that BG that can release therapeutic levels of fluoride may find use in a range of bone regeneration applications.

Inflammatory markers and the risk of hip fracture: the Women's Health Initiative

Cytokines play a major role in bone remodeling in vitro and in animal models, with evidence supporting the involvement of inflammatory markers in the pathogenesis of osteoporosis. However, less is known about the longitudinal association of inflammatory markers with hip fracture. We tested whether high receptor levels of proinflammatory cytokines are associated with an increased risk of hip fracture in older women. We used a nested case-control study design from the Women's Health Initiative Observational Study (WHI-OS) and selected 400 cases with physician-adjudicated incident hip fractures and 400 controls matched on age, race, and date of blood draw. Participants were chosen from 39,795 postmenopausal women without previous hip fractures, not using estrogens or other bone-active therapies. Incident hip fractures (median follow-up 7.1 years) were verified by review of radiographs and confirmed by blinded central adjudicators. Hip fractures with a pathological cause were excluded. In multivariable models, the risk of hip fracture for subjects with the highest levels of inflammatory markers (quartile 4) compared with those with lower levels (quartiles 1, 2, and 3) was 1.43 (95% confidence interval [CI], 0.98-2.07) for interleukin-6 (IL-6) soluble receptor (SR), 1.40 (95% CI, 0.97-2.03) for tumor necrosis factor (TNF) SR1, and 1.56 (95% CI, 1.09-2.22) for TNF SR2. In subjects with all three markers in the highest quartile, the risk ratio of fracture was 2.76 (95% CI, 1.22-6.25) in comparison with subjects with 0 or 1 elevated marker(s) (p trend = 0.018). Elevated levels of inflammatory markers for all three cytokine-soluble receptors were associated with an increased risk of hip fractures in older women. Future clinical trials should test whether interventions to decrease inflammatory marker levels reduces hip fractures.

Modifiable risk factors associated with bone deficits in childhood cancer survivors

BACKGROUND

To determine the prevalence and severity of bone deficits in a cohort of childhood cancer survivors (CCS) compared to a healthy sibling control group, and the modifiable factors associated with bone deficits in CCS.

METHODS

Cross-sectional study of bone health in 319 CCS and 208 healthy sibling controls. Bone mineral density (BMD) was measured by dual-energy x-ray absorptiometry (DXA). Generalized estimating equations were used to compare measures between CCS and controls. Among CCS, multivariable logistic regression was used to evaluate odds ratios for BMD Z-score ≤ -1.

RESULTS

All subjects were younger than 18 years of age. Average time since treatment was 10.1 years (range 4.3 - 17.8 years). CCS were 3.3 times more likely to have whole body BMD Z-score ≤ -1 than controls (95% CI: 1.4-7.8; p = 0.007) and 1.7 times more likely to have lumbar spine BMD Z-score ≤ -1 than controls (95% CI: 1.0-2.7; p = 0.03). Among CCS, hypogonadism, lower lean body mass, higher daily television/computer screen time, lower physical activity, and higher inflammatory marker IL-6, increased the odds of having a BMD Z-score ≤ -1.

CONCLUSIONS

CCS, less than 18 years of age, have bone deficits compared to a healthy control group. Sedentary lifestyle and inflammation may play a role in bone deficits in CCS. Counseling CCS and their caretakers on decreasing television/computer screen time and increasing activity may improve bone health.

The relationship between osteoclastogenic and anti-osteoclastogenic pro-inflammatory cytokines differs in human osteoporotic and osteoarthritic bone tissues

Background

Pro-inflammatory cytokines possess osteoclastogenic or anti-osteoclastogenic activities. They influence osteoclasts directly or via the receptor activator of nuclear factor κB (RANK), RANK ligand (RANKL) and osteoprotegerin (OPG) system. Recent evidence suggests that inflammation may play a role in osteoporosis (OP) and osteoarthritis (OA). We aimed therefore to determine whether there is a difference between both groups: first, in the expression of the osteoclastogenic and anti-osteoclastogenic cytokines, second, in correlation of these cytokines with bone mineral density (BMD) and levels of bone turnover markers (BTM) and third, in correlation between the expression of these cytokines and osteoclast specific genes and RANK/RANKL/OPG genes.

Methods

Human bone samples from 54 age and sex matched patients with OP or OA were collected during hip arthroplasty surgery. The expression of 25 genes encoding pro-inflammatory cytokines, their receptors, osteoclast specific genes and RANK/RANKL/OPG genes was measured using quantitative real-time PCR. Total hip, femoral neck and lumbar spine BMD and BTM in blood samples were measured. The comparison between OP and OA was assessed using Student's t-test or Mann-Whitney U test and correlations between gene expression, BMD and BTM were determined using nonparametric correlation.

Results

The results demonstrated a higher expression of interleukin (IL)-6 and IL-1α in OP, and interferon (IFN)-γ in OA (p < 0.0005). Negative correlations of total hip BMD with tumor necrosis factor-α (TNF-α) in OA and with RANKL/RANK in OP were found (p < 0.05). Significant correlations with BTM were shown for IL-1α and IFN-γ in OP (rho = 0.608 and -0.634) and for TNF-α, IL-6 and transforming growth factor-β1 (TGF-β1) in OA (rho = 0.591, -0.521 and 0.636). Results showed OP specific negative correlations (IFN-γ with ITGB3, IFN-β1 with CTSK, tartrate resistant acid phosphatase (TRAP), CALCR, RANK, RANKL, IL-1α with CTSK, OPG, IL-17A with CALCR) and positive (TGF-β1 with CTSK, TRAP, RANK), and OA specific negative (IL-1α with osteoclast associated immunoglobulin-like receptor (OSCAR), TNF-α with RANK, RANKL, OPG) and positive (IL-6 with RANK, RANKL, OPG) correlations.

Conclusions

Our results demonstrate that the relationship between osteoclastogenic and anti-osteoclastogenic pro-inflammatory cytokines differs in human OP and OA bone and could present an important factor for characteristics of OP and OA bone phenotypes.

Long-term aerobic exercise and omega-3 supplementation modulate osteoporosis through inflammatory mechanisms in post-menopausal women: a randomized, repeated measures study

BACKGROUND

Evidence indicates that dietary fats and physical activity influence bone health. The purpose of this study was to examine the effects of long-term aerobic exercise and omega-3 (N-3) supplementation on serum inflammatory markers, bone mineral density (BMD), and bone biomarkers in post-menopausal women.

METHODS

Seventy-nine healthy sedentary post-menopausal women aged 58-78 years participated in this study. Subjects were randomized to one of 4 groups: exercise + supplement (E+S, n = 21), exercise (E, n = 20), supplement (S, n = 20), and control (Con, n = 18) groups. The subjects in the E+S and E groups performed aerobic exercise training (walking and jogging) up to 65% of HRmax, three times a week for 24 weeks. Subjects in the E+S and S groups consumed 1000 mg/d N-3 for 24 weeks. The lumbar spine (L2-L4) and femoral neck BMD, serum tumor necrosis factor (TNF) α, interleukin (IL) 6, prostaglandin (PG) E2, estrogen, osteocalcin, 1, 25-dihydroxyvitamin D3 (1, 25 Vit D), C-telopeptide (CTX), parathyroid hormone (PTH) and calcitonin (CT) were measured at baseline, the end of week 12 and 24.

RESULTS

Serum estrogen, osteocalcin, 1, 25 Vit D, CT, L2-L4 and femoral neck BMD measures increased (P < 0.05) and the serum CTX, PTH, TNF-α, IL-6, and PGE2 decreased (P < 0.05) in E + S group after the 24 wk intervention but not in the E or S intervention groups. L2-L4 and femoral neck BMD, estrogen, osteocalcin, and CT were negatively (P < 0.05) correlated with TNF-α and PGE2. PTH and CT were correlated positively and negatively with IL-6, respectively (P < 0.05).

CONCLUSIONS

The present study demonstrates that long-term aerobic exercise training plus N-3 supplementation have a synergistic effect in attenuating inflammation and augmenting BMD in post-menopausal osteoporosis.