Is osteoporosis an autoimmune mediated disorder?

Bioactive Materials for Bone Regeneration: Biomolecules and Delivery Systems

Novel tissue regeneration strategies are constantly being developed worldwide. Research on bone regeneration is noteworthy, as many promising new approaches have been documented with novel strategies currently under investigation. Innovative biomaterials that allow the coordinated and well-controlled repair of bone fractures and bone loss are being designed to reduce the need for autologous or allogeneic bone grafts eventually. The current engineering technologies permit the construction of synthetic, complex, biomimetic biomaterials with properties nearly as good as those of natural bone with good biocompatibility. To ensure that all these requirements meet, bioactive molecules are coupled to structural scaffolding constituents to form a final product with the desired physical, chemical, and biological properties. Bioactive molecules that have been used to promote bone regeneration include protein growth factors, peptides, amino acids, hormones, lipids, and flavonoids. Various strategies have been adapted to investigate the coupling of bioactive molecules with scaffolding materials to sustain activity and allow controlled release. The current manuscript is a thorough survey of the strategies that have been exploited for the delivery of biomolecules for bone regeneration purposes, from choosing the bioactive molecule to selecting the optimal strategy to synthesize the scaffold and assessing the advantages and disadvantages of various delivery strategies.

The Impact of Long-Term Conditions and Comorbidity Patterns on COVID-19 Infection and Hospitalisation: A Cohort Study

INTRODUCTION

Older adults are more vulnerable to COVID-19 infections; however, little is known about which comorbidity patterns are related to a higher risk of COVID-19 infection. This study investigated the role of long-term conditions or comorbidity patterns on COVID-19 infection and related hospitalisations.

METHODS

This study included 4,428 individuals from Waves 8 (2016-2017) and 9 (2018-2019) of the English Longitudinal Study of Ageing (ELSA) who also participated in the ELSA COVID-19 Substudy in 2020. Comorbidity patterns were identified using an agglomerative hierarchical clustering method. The relationships between comorbidity patterns or long-term conditions and COVID-19-related outcomes were examined using multivariable logistic regression.

RESULTS

Among a representative sample of community-dwelling older adults in England, those with cardiovascular disease (CVD) and complex comorbidities had an almost double risk of COVID-19 infection (OR = 1.87, 95% CI = 1.42-2.46) but not of COVID-19-related hospitalisation. A similar pattern was observed for the heterogeneous comorbidities cluster (OR = 1.56, 95% CI = 1.24-1.96). The individual investigations of long-term conditions with COVID-19 infection highlighted primary associations with CVD (OR = 1.46, 95% CI = 1.23-1.74), lung diseases (OR = 1.40, 95% CI = 1.17-1.69), psychiatric conditions (OR = 1.40, 95% CI = 1.16-1.68), retinopathy/eye diseases (OR = 1.39, 95% CI = 1.18-1.64), and arthritis (OR = 1.27, 95% CI = 1.09-1.48). In contrast, metabolic disorders and diagnosed diabetes were not associated with any COVID-19 outcomes.

CONCLUSION

This study provides novel insights into the comorbidity patterns that are more vulnerable to COVID-19 infections and hospitalisations, highlighting the vulnerability of those with CVD and other complex comorbidities. These findings facilitate crucial new evidence that should be considered for appropriate screening measures and tailored interventions for older adults in the ongoing global outbreak.

Adherence to a healthy sleep pattern is associated with lower risks of incident falls and fractures during aging

Background

Autoimmune diseases are more common among people with unhealthy sleep behaviors, and these conditions have been linked to aging-related bone health. However, there have been few studies that examined the correlation between recently developed sleep patterns based on sleep duration, sleepiness, chronotype, snoring, insomnia, and the incidence of falls and fractures.

Methods

We used a newly developed sleep pattern with components of sleep 7 to 8 h per day, absence of frequent excessive daytime sleepiness, early chronotype, no snoring, and no frequent insomnia as healthy factors to study their relationship with the incidence of falls and fractures. The analysis was conducted among 289,000 participants from the UK Biobank.

Results

The mean follow-up period was 12.3 years (3.5 million person-years of follow-up), and 12,967 cases of falls and 16,121 cases of all fractures were documented. Compared to participants exhibiting an unfavorable sleep pattern, those adhering to a healthy sleep pattern experienced a 17% and 28% reduction in the risks of incident falls (hazard ratio [HR], 0.83; 95% CI, 0.74-0.93) and all fractures (HR, 0.72; 95% CI, 0.66-0.79) during follow-up. In addition, participants exhibiting a healthy sleep pattern, together with a high genetically determined bone mineral density (BMD), showed the lowest risks of falls and fractures.

Conclusion

A healthy sleep pattern was significantly linked to decreased risks of incident falls and fractures. The protective association was not modified by genetically determined BMD.

The impact of long-term conditions and comorbidity patterns on COVID-19 infection and hospitalisation: a cohort study

Introduction

Older adults are usually more vulnerable to COVID-19 infections; however, little is known about which comorbidity patterns are related to a higher probability of COVID-19 infection. This study investigated the role of long-term conditions or comorbidity patterns on COVID-19 infection and related hospitalisations.

Methods

This study included 4,428 individuals from Waves 8 (2016-2017) and 9 (2018-2019) of the English Longitudinal Study of Ageing (ELSA), who also participated in the ELSA COVID-19 Substudy in 2020. Comorbidity patterns of chronic conditions were identified using an agglomerative hierarchical clustering method. The relationships between comorbidity patterns or long-term conditions and COVID-19 related outcomes were examined using multivariable logistic regression.

Results

Among a representative sample of community-dwelling older adults in England, those with cardiovascular disease (CVD) and complex comorbidities had an almost double risk of COVID-19 infection (OR=1.87, 95% CI=1.42-2.46) but not of COVID-19 related hospitalisation. A similar pattern was observed for the heterogeneous comorbidities cluster (OR=1.56, 95% CI=1.24-1.96). The individual investigations of long-term conditions with COVID-19 infection highlighted primary associations with CVD (OR=1.46, 95% CI=1.23-1.74), lung diseases (OR=1.40, 95% CI=1.17-1.69), psychiatric conditions (OR=1.40, 95% CI=1.16-1.68), retinopathy/eye diseases (OR=1.39, 95% CI=1.18-1.64), and arthritis (OR=1.27, 95% CI=1.09-1.48). In contrast, metabolic disorders and diagnosed diabetes were not associated with any COVID-19 outcomes.

Discussion/Conclusion

This study provides novel insights into the comorbidity patterns that are more vulnerable to COVID-19 infections and highlights the importance of CVD and complex comorbidities.These findings facilitate crucial new evidence for appropriate screening measures and tailored interventions for older adults in the ongoing global outbreak.

Oxidative Stress and Inflammation in Osteoporosis: Molecular Mechanisms Involved and the Relationship with microRNAs

Osteoporosis is characterized by the alteration of bone homeostasis due to an imbalance between osteoclastic bone resorption and osteoblastic bone formation. Estrogen deficiency causes bone loss and postmenopausal osteoporosis, the pathogenesis of which also involves oxidative stress, inflammatory processes, and the dysregulation of the expression of microRNAs (miRNAs) that control gene expression at post-transcriptional levels. Oxidative stress, due to an increase in reactive oxygen species (ROS), proinflammatory mediators and altered levels of miRNAs enhance osteoclastogenesis and reduce osteoblastogenesis through mechanisms involving the activation of MAPK and transcription factors. The present review summarizes the principal molecular mechanisms involved in the role of ROS and proinflammatory cytokines on osteoporosis. Moreover, it highlights the interplay among altered miRNA levels, oxidative stress, and an inflammatory state. In fact, ROS, by activating the transcriptional factors, can affect miRNA expression, and miRNAs can regulate ROS production and inflammatory processes. Therefore, the present review should help in identifying targets for the development of new therapeutic approaches to osteoporotic treatment and improve the quality of life of patients.

Dietary inflammatory index and osteoporosis: the National Health and Nutrition Examination Survey, 2017-2018

PURPOSE

The dietary inflammatory index (DII) is a scoring system to quantify the inflammatory effects of nutrients and foods. Inflammation may affect bone health. The purpose of this study was to explore the relationships of DII with bone mineral density (BMD) and osteoporosis.

METHODS

This study involved 1023 women and 1080 men (age ≥ 50) in the US National Health and Nutrition Survey (NHANES), 2017-2018. Multivariable linear regression models were used to estimate the associations between DII and BMD. Association between DII and osteoporosis was tested with multivariable logistic regression models.

RESULTS

In women, DII was negatively associated with total hip and femoral neck BMD after adjusting for covariates (P < 0.05). In men, DII was negatively associated with lumbar spine BMD (P < 0.05). DII was positively associated with osteoporosis in women (P < 0.05). The odds ratios (ORs) (95% CI) for osteoporosis associated with DII quartiles 2, 3 and 4 vs. quartile 1 were 2.95 (1.08, 8.09), 5.63 (2.87, 11.04), and 6.14(2.55, 14.78), respectively. No significant association was observed in men.

CONCLUSIONS

Higher DII scores were associated with increase osteoporosis risk in women, while no association was found in men. Greater pro-inflammatory diets might be associated with lower BMD in both women and men.

Assessment of Metabolic Markers and Osteoporosis in 250 Patients with Superior Semicircular Canal Dehiscence Treated With Middle Fossa Craniotomy

BACKGROUND

Superior semicircular canal dehiscence (SSCD) is caused by bony defects in the osseous shell of the arcuate eminence separating the labyrinth and the intracranial space. This pathologic third window causes hydroacoustic transmission resulting in debilitating symptoms. We examine the pathophysiologic association between metabolic markers, previous medical history, and SSCD symptoms before and after middle fossa craniotomy (MFC) treatment.

METHODS

This study was conducted between March 2011 and September 2020 with patients with SSCD who underwent MFC. We used a Fisher test to compare variables, including bilateral SSCD, second surgery, ear anomaly, osteoporosis, arthritis, vitamin D, and preoperative/postoperative symptoms, and others. Point-biserial correlation analysis was performed to test correlations between continuous variables and categorical variables.

RESULTS

A total of 250 patients with SSCD underwent MFC repair. There was significant postoperative resolution in all symptoms (P < 0.0001). Laboratory 25-hydroxyvitamin D values correlated with preoperative aural fullness (r_pb= 0.29; P = 0.03), and preoperative disequilibrium (r_pb= -0.32; P = 0.02). Serum calcium values correlated with preoperative hearing loss (r_pb= 0.16; P = 0.02). Osteoporosis history (n = 16; 6%) was more prevalent in female patients (P = 0.0001), associated with higher levels of preoperative hearing loss (odds ratio, 4.56; P = 0.02) and higher postoperative hearing loss resolution (odds ratio, 2.89; P = 0.0509).

CONCLUSIONS

Certain metabolic markers may predict SSCD presentation before and after surgery. Previous history of osteoporosis, autoimmune conditions, or arthritis may play a role in SSCD pathophysiology and can help predict clinical outcomes. Future evaluation should take metabolic laboratory values and acquire an exact medical history.

Higher modified dietary inflammatory index is associated with increased risk of osteoporosis in US adults: Data from NHANES

Objective

The aim of this study was to study the relationship between modified dietary inflammatory index (MDII) score with osteoporosis (OP) in adult Americans.

Methods

Data were extracted from the United States National Health and Nutrition Examination Survey (NHANES) (2007–2008, 2009–2010, 2013–2014, and 2017–2018). In this cross-sectional study, 5,446 participants were included and analyzed. Potential dietary inflammatory was assessed by MDII score (24-h recall), a composite method computed according to the relationship between nutrients and systemic pro-inflammatory cytokine level, and was further classified into tertiles. Weighted multivariable logistic regression analysis was employed to examine the associations between OP and MDII scores.

Results

In weighted multivariable-adjusted logistic regression models, the highest tertile of MDII score was associated with an increased risk of OP [odds ratio (OR): 1.73, 95% confidence interval (95 CI%): 1.14–2.63]. In participants aged above 59 years, a higher MDII score showed a higher risk of OP (OR: 1.92; 95 CI%: 1.16–3.15). In the sex-stratified models, the results remained significant only among women (OR: 1.80; 95% CI: 1.02–3.17). In the menopausal status stratified model, after adjusting potential confounding variables, the association between the MDII score, either as a categorical (OR: 1.88; 95% CI: 1.07–3.13) or continuous variables (OR: 1.19; 95%CI: 1.02–1.38), and OP risk was significant among postmenopausal women.

Conclusion

Our study indicates that a higher MDII score (pro-inflammatory effect) is significantly associated with an increased risk of OP in US adults, especially among those postmenopausal women more than 60 years. This study further supports that those dietary changes have the potential to prevent OP.

The Rising Era of “Immunoporosis”: Role of Immune System in the Pathophysiology of Osteoporosis

Discoveries in the last few years have emphasized the existence of an enormous breadth of communication between bone and the immune system in maintaining skeletal homeostasis. Originally, the discovery of various factors was assigned to the immune system viz. interleukin (IL)-6, IL-10, IL-17, tumor necrosis factor (TNF)-α, receptor activator of nuclear factor kappa B ligand (RANKL), nuclear factor of activated T cells (NFATc1), etc., but now these factors have also been shown to have a significant impact on osteoblasts (OBs) and osteoclasts (OCs) biology. These discoveries led to an alteration in the approach for the treatment of several bone pathologies including osteoporosis. Osteoporosis is an inflammatory bone anomaly affecting more than 500 million people globally. In 2018, to highlight the importance of the immune system in the pathophysiology of osteoporosis, our group coined the term “immunoporosis”. In the present review, we exhaustively revisit the characteristics, mechanism of action, and function of both innate and adaptive immune cells with the goal of understanding the potential of immune cells in osteoporosis. We also highlight the Immunoporotic role of gut microbiota (GM) for the treatment and management of osteoporosis. Importantly, we further discuss whether an immune cell-based strategy to treat and manage osteoporosis is feasible and relevant in clinical settings.

TRAP5b and RANKL/OPG Predict Bone Pathology in Patients with Gaucher Disease

Background and objective: Bone involvement occurs in 75% of patients with Gaucher disease (GD), and comprises structural changes, debilitating pain, and bone density abnormalities. Osteoporosis is a silent manifestation of GD until a pathologic fracture occurs. Thus, early diagnosis is crucial for identifying high-risk patients in order to prevent irreversible complications. Methods: Thirty-three patients with GD were assessed prospectively to identify predictive markers associated with bone density abnormalities, osteopenia (OSN), and osteoporosis (OSR). Subjects were categorized into three cohorts based on T- or Z-scores of bone mineral density (BMD). The first GD cohort consisted of those with no bone complications (Z-score ≥ −0.9; T-scores ≥ −1), the second was the OSN group (−1.8 ≥ Z-score ≥ −1; −2.5 ≥ T-score ≥ −1), and the third was the OSR group (Z-score ≤ −1.9; T-scores ≤ −2.5). Serum levels of TRAP5b, RANKL, OPG, and RANK were quantified by enzyme-linked immunosorbent assays. Results: TRAP5b levels were increased in GD patients, and showed a positive correlation with GD biomarkers, including plasma glucosylsphingosine (lyso-Gb1) and macrophage activation markers CCL18 and chitotriosidase. The highest level of TRAP5b was measured in patients with osteoporosis. The elevation of RANKL and RANKL/OPG ratio correlated with osteopenia in GD. Conclusion: TRAP5b, RANKL, and RANKL/OPG elevation indicate osteoclast activation in GD. TRAP5b is a potential bone biomarker for GD with the ability to predict the progression of bone density abnormalities.

Role of OSCAR Signaling in Osteoclastogenesis and Bone Disease

Formation of mature bone-resorbing cells through osteoclastogenesis is required for the continuous remodeling and repair of bone tissue. In aging and disease this process may become aberrant, resulting in excessive bone degradation and fragility fractures. Interaction of receptor-activator of nuclear factor-κB (RANK) with its ligand RANKL activates the main signaling pathway for osteoclastogenesis. However, compelling evidence indicates that this pathway may not be sufficient for the production of mature osteoclast cells and that co-stimulatory signals may be required for both the expression of osteoclast-specific genes and the activation of osteoclasts. Osteoclast-associated receptor (OSCAR), a regulator of osteoclast differentiation, provides one such co-stimulatory pathway. This review summarizes our present knowledge of osteoclastogenesis signaling and the role of OSCAR in the normal production of bone-resorbing cells and in bone disease. Understanding the signaling mechanism through this receptor and how it contributes to the production of mature osteoclasts may offer a more specific and targeted approach for pharmacological intervention against pathological bone resorption.

Inflammation, Oxidative Stress, and Bone in Chronic Kidney Disease in the Osteoimmunology Era

Bone is not only a mineralized and apparently non-vital structure that provides support for locomotion and protection to inner organs. An increasing number of studies are unveiling new biologic functions and connections to other systems, giving the rise to new fields of research, such as osteoimmunology. The bone marrow niche, a new entity in bone physiology, seems to represent the site where a complex crosstalk between bone and immune/inflammatory responses takes place. An impressive interplay with the immune system is realized in bone marrow, with reciprocal influences between bone cells and haematopoietic cells. In this way, systemic chronic inflammatory diseases realize a crosstalk with bone, resulting in bone disease. Thus, pathogenetic links between chronic kidney disease-mineral bone disorders and osteoporosis, cardiovascular disease, and ageing are common. The aim of this narrative review is to provide a general view of the progresses in the field of bone research and their potential clinical implications, with emphasis on the links with inflammation and the connections to osteoimmunology and chemokines.

Autoimmunological serum parameters and bone mass density in premature ovarian insufficiency: a retrospective cohort study

Purpose

It is still not clear whether to screen women with primary premature ovarian insufficiency for autoimmunity. Moreover, a possible association of autoimmunity with decreased bone mass density in premature ovarian insufficiency patients has not been evaluated. Thus, the objectives of this study were to review our experience with the use of an autoimmune screening panel in premature ovarian insufficiency women and to focus on bone mass density.

Methods

In a retrospective cohort study, 76 chromosomally normal women with primary premature ovarian insufficiency were included. The main outcome parameters were the results of an autoimmune screening panel and of dual-energy X-ray absorptiometry.

Results

Median age was 33 years. Sixty percent of premature ovarian insufficiency patients revealed abnormal dual-energy X-ray absorptiometry results (minimal T-score < −1.0). Any signs of autoimmunity were found in 21 women (36.2%). The most frequent abnormal results were increased thyroperoxidase antibodies (24.1%) and thyroglobulin antibodies (20.7%). A longer duration of amenorrhea (β = −0.015; p = 0.007), any abnormality during autoimmune screening (β = −0.940; p = 0.010), and a lower body mass index (β = −0.057; p = 0.036) were associated with a lower minimal T-score.

Conclusion

In chromosomally normal women with primary premature ovarian insufficiency, the prevalence of autoimmunity and decreased bone mass density seem high. Our data highlight the association between autoimmune abnormalities and decreased dual-energy X-ray absorptiometry results.

Identification of osteoporosis markers through bioinformatic functional analysis of serum proteome

Osteoporosis is a severe chronic skeletal disorder that increases the risks of disability and mortality; however, the mechanism of this disease and the protein markers for prognosis of osteoporosis have not been well characterized. This study aims to characterize the imbalanced serum proteostasis, the disturbed pathways, and potential serum markers in osteoporosis by using a set of bioinformatic analyses. In the present study, the large-scale proteomics datasets (PXD006464) were adopted from the Proteome Xchange database and processed with MaxQuant. The differentially expressed serum proteins were identified. The biological process and molecular function were analyzed. The protein-protein interactions and subnetwork modules were constructed. The signaling pathways were enriched. We identified 209 upregulated and 230 downregulated serum proteins. The bioinformatic analyses revealed a highly overlapped functional protein classification and the gene ontology terms between the upregulated and downregulated protein groups. Protein-protein interactions and pathway analyses showed a high enrichment in protein synthesis, inflammation, and immune response in the upregulated proteins, and cell adhesion and cytoskeleton regulation in the downregulated proteins. Our findings greatly expand the current view of the roles of serum proteins in osteoporosis and shed light on the understanding of its underlying mechanisms and the discovery of serum proteins as potential markers for the prognosis of osteoporosis.

lncRNA SNHG1 attenuates osteogenic differentiation via the miR‑101/DKK1 axis in bone marrow mesenchymal stem cells

The imbalance induced by inhibition of bone mesenchymal stem cell (BMSC) osteogenic differentiation results in osteoporosis (OP); however, the underlying regulatory mechanism is not completely understood. Long non-coding RNAs (lncRNAs) serve crucial roles in osteogenic differentiation; therefore, investigating their regulatory role in the process of osteogenic differentiation may identify a promising therapeutic target for OP. The expression of small nucleolar RNA host gene 1 (SNHG1), Dickkopf 1 (DKK1), microRNA (miR)-101, RUNX family transcription factor 2 (RUNX2), osteopontin (OPN) and osteocalin (OCN) were detected via reverse transcription-quantitative PCR. The protein expression levels of DKK1, β-catenin, RUNX2, OPN, OCN, osterix and collagen type I α1 chain were analyzed by performing western blotting. The osteoblastic phenotype was assessed by conducting alkaline phosphatase activity detection and Alizarin Red staining. The interaction between SNHG1 and miR-101 was validated by bioinformatics and luciferase assays. The regulatory role of SNHG1 in BMSC osteogenic differentiation was assessed. SNHG1 expression was downregulated in a time-dependent manner during the process of osteogenic differentiation. SNHG1 overexpression inhibited osteogenic differentiation compared with the pcDNA group. The results indicated that SNHG1 and DKK1 directly interacted with miR-101. Moreover, SNHG1 regulated the Wnt/β-catenin signaling pathway to inhibit osteogenic differentiation via the miR-101/DKK1 axis. The present study indicated that lncRNA SNHG1 could attenuate BMSC osteogenic differentiation via the miR-101/DKK1 axis as a competitive endogenous RNA. Therefore, the present study furthered the current understanding of the potential mechanism underlying lncRNAs in in osteogenic differentiation.

Osteocalcin and regulatory cytokine imbalance in children with congenital cleft lip and palate

The aim of the work was a comprehensive assessment of the cytokine system and peripheral blood osteocalcin with the establishment of features of their interconnections in children with congenital cleft lip and palate (CCLP) in comparison with corresponding controls at different age periods. Levels of IL17, IL4, IL6, IL1β, IFNγ and osteocalcin were analyzed by enzyme immunoassay in the peripheral blood of 80 children (0-12 months, 1-3 years, 4-9 years, 10-15 years) with CCLP and age-appropriate control of healthy individuals (40 people). An analysis of the obtained data shows that in children with CCLP we revealed significant differences between pro-inflammatory (IL1β, IL6, IL17), regulatory (IFNγ), anti-inflammatory (IL4) cytokines and osteocalcin compared with controls. Differences were found in the content of IL17, IFNγ, IL4 and osteocalcin in healthy children and in children with CCLP in postnatal ontogenesis. Cytokine deregulation of immunosteogenesis in CCLP, leading to a significant deficit of osteocalcin in the first year of life due to imbalance of the cytokine profile: discordant IL17, IFNγ and IL4 were detected. Obtained data are undoubtedly important in the future for developing new strategies for targeted therapy aimed at normalizing osteocalcin levels at different age periods in children with CCLP.

Linking skeletal muscle aging with osteoporosis by lamin A/C deficiency

The nuclear lamina protein lamin A/C is a key component of the nuclear envelope. Mutations in the lamin A/C gene (LMNA) are identified in patients with various types of laminopathy-containing diseases, which have features of accelerated aging and osteoporosis. However, the underlying mechanisms for laminopathy-associated osteoporosis remain largely unclear. Here, we provide evidence that loss of lamin A/C in skeletal muscles, but not osteoblast (OB)-lineage cells, results in not only muscle aging-like deficit but also trabecular bone loss, a feature of osteoporosis. The latter is due in large part to elevated bone resorption. Further cellular studies show an increase of osteoclast (OC) differentiation in cocultures of bone marrow macrophages/monocytes (BMMs) and OBs after treatment with the conditioned medium (CM) from lamin A/C-deficient muscle cells. Antibody array screening analysis of the CM proteins identifies interleukin (IL)-6, whose expression is markedly increased in lamin A/C-deficient muscles. Inhibition of IL-6 by its blocking antibody in BMM-OB cocultures diminishes the increase of osteoclastogenesis. Knockout (KO) of IL-6 in muscle lamin A/C-KO mice diminishes the deficits in trabecular bone mass but not muscle. Further mechanistic studies reveal an elevation of cellular senescence marked by senescence-associated beta-galactosidase (SA-β-gal), p16Ink4a, and p53 in lamin A/C-deficient muscles and C2C12 muscle cells, and the p16Ink4a may induce senescence-associated secretory phenotype (SASP) and IL-6 expression. Taken together, these results suggest a critical role for skeletal muscle lamin A/C to prevent cellular senescence, IL-6 expression, hyperosteoclastogenesis, and trabecular bone loss, uncovering a pathological mechanism underlying the link between muscle aging/senescence and osteoporosis.

Bone, inflammation and chronic kidney disease

Increasing knowledge on inflammatory mediators and bone metabolism highlights the relationship between inflammation and bone disease. During acute illness, inflammatory cells and cytokines modulate bone cells activity so as to mobilize calcium seemingly to supply the metabolic requirements for immune response. In case of long lasting, chronic inflammatory states a condition of maladaptive, smouldering inflammation is realized and negatively affects calcium bone balance. Aging, now nicknamed inflammaging, is regarded as a chronic inflammatory condition, characterized by increased circulating inflammatory cytokines, that contributes to the development of osteoporosis, cardiovascular diseases and chronic kidney disease. In patients with renal insufficiency, the development of bone and mineral disorders (so called CKD-MBD "syndrome") is now a recognized pathogenic factor for the seemingly accelerated process of aging and for the increased risk of cardiovascular death in these patients. The adaptive changes in mineral and bone metabolism developing in the early stages of chronic kidney disease could represent a hypothetical model of accelerated aging, osteoporosis and cardiovascular disease.

IDO and Kynurenine Metabolites in Peripheral and CNS Disorders

The importance of the kynurenine pathway in normal immune system function has led to an appreciation of its possible contribution to autoimmune disorders such as rheumatoid arthritis. Indoleamine-2,3-dioxygenase (IDO) activity exerts a protective function, limiting the severity of experimental arthritis, whereas deletion or inhibition exacerbates the symptoms. Other chronic disorder with an inflammatory component, such as atherosclerosis, are also suppressed by IDO activity. It is suggested that this overall anti-inflammatory activity is mediated by a change in the relative production or activity of Th17 and regulatory T cell populations. Kynurenines may play an anti-inflammatory role also in CNS disorders such as Huntington's disease, Alzheimer's disease and multiple sclerosis, in which signs of inflammation and neurodegeneration are involved. The possibility is discussed that in Huntington's disease kynurenines interact with other anti-inflammatory molecules such as Human Lymphocyte Antigen-G which may be relevant in other disorders. Kynurenine involvement may account for the protection afforded to animals with cerebral malaria and trypanosomiasis when they are treated with an inhibitor of kynurenine-3-monoxygenase (KMO). There is some evidence that changes in IL-10 may contribute to this protection and the relationship between kynurenines and IL-10 in arthritis and other inflammatory conditions should be explored. In addition, metabolites of kynurenine downstream of KMO, such as anthranilic acid and 3-hydroxy-anthranilic acid can influence inflammation, and the ratio of these compounds is a valuable biomarker of inflammatory status although the underlying molecular mechanisms of the changes require clarification. Hence it is essential that more effort be expended to identify their sites of action as potential targets for drug development. Finally, we discuss increasing awareness of the epigenetic regulation of IDO, for example by DNA methylation, a phenomenon which may explain differences between individuals in their susceptibility to arthritis and other inflammatory disorders.

[The impact of disbalance of regulatory cytokines and osteocalcin on osteogenesis in children with congenital cleft lip and palate in postnatal ontogenesis]

The aim of the work was a comprehensive assessment of the system of cytokines and peripheral blood osteocalcin with the establishment of features of their interconnections in children with congenital cleft lip and palate (CCLP) in comparison with the corresponding controls at different age periods. In the peripheral blood of 80 children (0-12 months, 1-3 years, 4-9 years, 10-15 years) with osteocalcin and IL17, IL4, congenital cleft lip and palate and age-appropriate control of healthy individuals (40 people) IL6, IL1β, IFNγ by enzyme immunoassay. An analysis of the data obtained with CCLP revealed significant differences in the dynamics of the relationship between pro-inflammatory (IL1β, IL6, IL17), regulatory (IFNγ), anti-inflammatory (IL4) cytokines and osteocalcin compared with controls. The patterns of changes and effects of IL17, IFNγ, IL4 and osteocalcin in healthy children and in children with congenital cleft lip and palate in postnatal ontogenesis were established. Cytokine dysregulation of immunosteogenesis in CCLP, leading to a significant deficit of osteocalcin in the first year of life due to an imbalance of the cytokine profile: discordant IL17, IFNγ and IL4 were detected. Thus, the data obtained are undoubtedly important in the future for developing new strategies for targeted therapy aimed at normalizing osteocalcin levels at different age periods in children with congenital cleft lip and palate.

Melatonin Reverses the Loss of Stemness Induced by TNF-α in Human Bone Marrow Mesenchymal Stem Cells through Upregulation of YAP Expression

Mesenchymal stem cells (MSCs) are promising candidates for tissue regeneration and disease treatment. However, long-term in vitro culture results in loss of MSC stemness. The inflammation that occurs at stem cell transplant sites (such as that resulting from TNF-α) is a contributing factor for stem cell treatment failure. Currently, there is little evidence regarding the protective role of melatonin with regard to the negative effects of TNF-α on the stemness of MSCs. In this study, we report a melatonin-based method to reduce the inflammatory effects on the stemness of bone marrow mesenchymal stem cells (BMMSCs). The results of colony formation assays, Alizarin red staining, western blotting, and reverse transcription-polymerase chain reactions suggest that melatonin can reverse the inflammatory damage caused by TNF-α treatment in the third, seventh, and tenth generations of primary BMMSCs (vs. control and the TNF-α-treated group). Meanwhile, a detailed analysis of the molecular mechanisms showed that the melatonin receptor and YAP signaling pathway are closely related to the role that melatonin plays in negative inflammatory effects against BMMSCs. In addition, in vivo experiments showed that melatonin could reverse the damage caused by TNF-α on bone regeneration by BMMSCs in nude mice. Overall, our results suggest that melatonin can reverse the loss of stemness caused by inflammatory factor TNF-α in BMMSCs. Our results also provide a practical strategy for the application of BMMSCs in tissue engineering and cell therapy.

IDO activation, inflammation and musculoskeletal disease

The IDO/kynurenine pathway is now established as a major regulator of immune system function. The initial enzyme, indoleamine 2,3-dioxygenase (IDO1) is induced by IFNγ, while tryptophan-2,3-dioxygenase (TDO) is induced by corticosteroids. The pathway is therefore positioned to mediate the effects of systemic inflammation or stress-induced steroids on tissue function and its expression increases with age. Disorders of the musculoskeletal system are a common feature of ageing and many of these conditions are characterized by an inflammatory state. In inflammatory arthritis and related disorders, kynurenine protects against the development of disease, while inhibition or deletion of IDO1 increases its severity. The long-term regulation of autoimmune disorders may be influenced by the epigenetic modulation of kynurenine pathway genes, with recent data suggesting that methylation of IDO may be involved. Osteoporosis is also associated with abnormalities of the kynurenine pathway, reflected in an inversion of the ratio between blood levels of the metabolites anthranilic acid and 3-hydroxy-anthranilic acid. This review discusses evidence to date on the role of the IDO/kynurenine pathway and the highly prevalent age-related disorders of osteoporosis and rheumatoid arthritis and identifies key areas that require further research.

Determinants of low bone mineral density in people with multiple sclerosis: Role of physical activity

BACKGROUND

People with multiple sclerosis (PwMS) have reduced bone mineral density (BMD), but the causes are unclear. Some factors that may cause reduced BMD in PwMS have been understudied, including physical activity, inflammation, cortisol, symptomatic fatigue, and depression. The aim of this study was to investigate factors that may uniquely contribute to reduced BMD in PwMS as compared to people without MS. We hypothesized that physical activity would be the primary determinant of low BMD in PwMS, with additional contributions from inflammation and sympathetic nervous system activation.

METHODS

We tested 23 PwMS (16 women; median EDSS: 2) and 22 control participants (16 women). BMD was measured from the femoral neck and lumbar spine with dual x-ray absorptiometry. Disability was measured with the Expanded Disability Status Scale, and functional capacity was measured with the Multiple Sclerosis Functional Composite. Questionnaires measured symptomatic fatigue and depression. A blood draw was used to measure calcium, phosphate, vitamin D, N-terminal telopeptide, osteopontin, and cytokine markers of inflammation. Physical activity was measured with accelerometry. Salivary cortisol and cardiac heart rate variability also were obtained. All outcome variables were compared between groups with independent samples t-tests. Variables that were different between groups and significantly correlated (Pearson product-moment) with femoral neck BMD, were included in a theoretical model to explain femoral neck BMD. The expected direction of relations in the theoretical model were developed based upon the results of previous research. A Bayesian path analysis was used to test the relations of predictive variables with femoral neck BMD and interrelations among predictive variables, as detailed in the theoretical model.

RESULTS

PwMS had lower BMD at the femoral neck than controls (p = =0.04; mean difference: -0.09; 95% CI: -0.2, -0.004; Cohen's d = =0.65), and there was a smaller, statistically non-significant difference in BMD at the lumbar spine (p = =0.07; mean difference: -0.08; 95% CI: -0.17, 0.007; Cohen's d = =0.59). PwMS also had lower functional capacity (p ≤ 0.001; Cohen's d = =1.50), greater fatigue (p<0.001; Cohen's d = =1.88), greater depression (p<0.001; d = =1.31), and decreased physical activity (p = =0.03; Cohen's d = =0.62). Using path analysis to test our theoretical model, we found that disability (standardized estimate= -0.17), physical activity (standardized estimate=0.39), symptomatic fatigue (standardized estimate= -0.36), depression (standardized estimate= -0.30), and inflammatory markers (standardized estimate=0.27) explained 51% of the variance in femoral neck BMD. Inflammatory markers were also predictive of disability (standardized estimate=0.44) and physical activity (standardized estimate= -0.40). Symptomatic fatigue and depression were correlated (r = =0.64).

CONCLUSION

Physical activity, symptomatic fatigue, depression, disability, and inflammation all contributed independently to decreased femoral neck BMD in PWMS. Bone metabolism in PwMS is complex. Efforts to increase physical activity and address symptomatic fatigue and depression may improve bone mineral density in PwMS. Future research should investigate the mechanisms through which symptomatic fatigue and depression contribute to reduced BMD in PwMS.

Circulating Serum Amyloid A, hs-CRP and Vitamin D Levels in Postmenopausal Osteoporosis

Background:

Both vitamin D and inflammation were investigated as important players in the pathogenesis of postmenopausal osteoporosis. This study compared vitamin D, inflammatory the biomarkers serum levels and their association with bone mineral density (BMD) in case and control groups to evaluate the possible immune-regulatory effect of vitamin D in this population.

Materials and Methods:

Participants in post-menopausal age, were categorized to 44 osteoporotic vs. 44 healthy aged-matched women according to WHO criteria. Total BMD, T- scores, Z-scores as well as fracture risk were measured in both groups, using Hologic system Dual-energy X-ray absorptiometry (DEXA). Serum 25-OH vitamin D, high sensitive CRP (hs-CRP) and serum amyloid A (SAA) were compared between groups. The association between serum biomarkers level and BMD were also investigated. The same evaluations were performed for vitamin D deficient (<20 ng/mL) and non-deficient (≥20 ng/mL) subgroups.

Results:

Vitamin D deficiency was higher in the osteoporotic group (32.6%) in comparison with the control group (25.6%), but the differences were not significant (P=0.47). There were no significant differences in serum levels of hs-CRP and SAA (P=0.83 and P=0.39) as well. No significant association between serum inflammatory biomarkers, vitamin D, and BMD were detected (P≥0.05). The results were the same for vitamin D deficient and non-deficient subgroups (P≥0.05).

Conclusion:

In the current study, the beneficial effects of vitamin D as a result of its immune-regulatory mechanisms was not reached. Larger scale studies might pave the way to define vitamin D benefits in postmenopausal osteoporosis.

Increased risk of osteoporotic fractures in Swedish patients with rheumatoid arthritis despite early treatment with potent disease-modifying anti-rheumatic drugs: a prospective general population-matched cohort study

Objective: To study the difference in incidence and risk of fragility fractures between rheumatoid arthritis (RA) patients followed up early in the disease and the general population in Sweden; and the fracture risk changes in RA patients diagnosed in the 1990s and 2000s because of earlier, more potent pharmacological treatment in the later period.Method: Patients with early RA were recruited from the BARFOT cohort, a Swedish multicentre observational study of early RA patients (n = 2557). All patients fulfilled 1987 American College of Rheumatology criteria and were included between 1992 and 2006. Each patient was matched by gender, age, and residential area with four controls from the general population (n = 10 228). Fractures of forearm, upper arm, and hip were identified by ICD-9 and ICD-10 codes through Swedish national medical registries.Results: During follow-up of 12.9 ± 4.7 years (mean ± sd), 14% (n = 470) of RA patients and 11% (n = 1418) of controls experienced a fracture (p < 0.001). When dividing the patients and controls into two groups according to inclusion period, an 8 year follow-up time was used. RA patients included in the 1990s had a higher incidence rate (IR) of hip and other fractures. RA patients included in the 2000s had a higher IR of all fracture sites. The hazard ratio of fractures was 1.4 in the total RA cohort, and the risk was increased in both the 1990s and 2000s.Conclusion: We observed an increased risk of fragility fractures in RA patients diagnosed in both the 1990s and 2000s, despite patients in the 2000s obtaining potent pharmacological treatment early in the disease.

Serum C-C Motif Ligand 11/eotaxin-1 May Serve as a Candidate Biomarker for Postmenopausal Osteoporosis

Background

The chemokine C-C motif ligand 11, also known as eotaxin-1, has been identified as a novel mediator of inflammatory bone resorption. However, little is known regarding a potential role for CCL11/Eotaxin-1 in postmenopausal osteoporosis.

Objective

The scope of this study was to explore the relationship between serum CCL11/Eotaxin-1 concentrations and disease progression of postmenopausal females with osteoporosis.

Methods

A total of 83 postmenopausal women diagnosed with osteoporosis were enrolled. Meanwhile, 82 postmenopausal women with normal bone mineral density (BMD) and 85 healthy controls inner child-bearing age were enrolled as control. The Dual-energy X-ray absorptiometry was used to examine the BMDs at the femoral neck, lumbar spine 1-4 and total hip of all participants. Serum CCL11/Eotaxin-1 levels were examined by enzyme-linked immunosorbent assay. We also included inflammation marker interleukin-6 (IL-6) as well as a serum marker of bone resorption C-telopeptide cross-linked collagen type 1 (CTX-1). The Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) were recorded to evaluate the clinical severity in POMP females.

Results

Serum CCL11/Eotaxin-1 levels were significantly elevated in postmenopausal osteoporotic patients PMOP patients compared with PMNOP and healthy controls. We observed a significant negative correlation of serum CCL11/Eotaxin-1 levels with lumbar spine, femoral neck and total hip BMD. Furthermore, serum CCL11/ Eotaxin-1 concentrations were also positively related to the VAS and ODI scores. Last, serum CCL11/ Eotaxin-1 concentrations were positively associated with IL-6 and CTX-1 levels. These correlations remain significant after adjusting for age and BMI. Multivariate linear regression analysis demonstrated that CCL11/Eotaxin-1 could serve as an independent marker.

Conclusions

Serum CCL 11/Eotaxin-1 may serve as a candidate biomarker for postmenopausal osteoporosis. Therapeutics targeting CCL11/Eotaxin-1 and its related signalling way to prevent and slow progression of PMOP deserve further study.

Orexins Facilitates Osteogenic Differentiation of MC3T3-E1 Cells

Dysfunction of osteoblastic bone formation and matrix mineralization plays a key role in the pathological development of osteoporosis. The orexin peptide orexin-A, a highly excitatory neuropeptide hormone, possesses various biological functions by activating its specific G protein-coupled receptors, orexin-1 receptor (OX1R) and orexin-2 receptor (OX2R). Here, we report that OX1R but not OX2R was expressed in MC3T3-E1 cells. Importantly, we found that orexin-A accelerated osteoblast differentiation and matrix mineralization in MC3T3-E1 cells, as manifested by elevation of physiological markers of osteoblastic differentiation [alkaline phosphatase (ALP) and osteogenic genes] and Alizarin Red staining, respectively. Importantly, our findings indicated that orexin-A significantly increased the expression of runt-related transcription factor 2 (Runx-2), which is the central transcriptional factor. Orexin-A treatment phosphorylated the kinase p38 mitogen-activated protein kinase (MAPK) in a dose- and time-dependent manner. Also, orexin-induced increase in gene expression (Runx-2, ALP, osteocalcin, and osterix) and matrix mineralization were prevented by the p38 MAPK specific inhibitor SB203580. Additionally, we also revealed that protein kinase D (PKD) is involved in the effects of Orexin-A on p38 MAPK activation and Runx-2 expression. Finally, we found that Orexin-A-induced osteoblastic formation and matrix mineralization and the activation of the PKD/p38 MAPK pathway are mediated by OX1R. Based on these findings, we concluded that activation of OX1R by orexin-A might possess a therapeutic strategy for bone disease. © 2018 IUBMB Life, 70(7):633-641, 2018.

Positive Association between Dietary Inflammatory Index and the Risk of Osteoporosis: Results from the KoGES_Health Examinee (HEXA) Cohort Study

Previous studies have found that diet’s inflammatory potential is related to various diseases. However, little is known about its relationship with osteoporosis. The aim of this study was to investigate the association between the dietary inflammatory index (DII^®) and osteoporosis risk in a large-scale prospective cohort study in Korea. This prospective cohort study included 159,846 participants (men 57,740; women 102,106) from South Korea with a mean follow-up of 7.9 years. The DII was calculated through a validated semi-quantitative FFQ (SQFFQ), and information on osteoporosis was self-reported by the participants. Analyses were performed by using a multivariable Cox proportional hazard model. Higher DII scores were associated with higher osteoporosis risk (HR 1.33; 95% CI 1.12–1.58). In women, a higher DII score indicated a higher risk of osteoporosis (HR 1.33; 95% CI 1.11–1.59). However, a hazards ratio of similar magnitude in men was not significant (HR 1.32; 95% CI 0.64–2.71). Post-menopausal women had higher risks of osteoporosis for higher DII scores (HR 1.33; 95% CI 1.09–1.63), whereas among pre-menopausal women, the relationship was not statistically significant (HR 1.39; 95% CI 0.87–2.21). Also, there was an increase in osteoporosis risk when the DII increased among women participants with irregular physical activity (HR 1.53; 95% CI 1.17–2.01); however, there was no statistically significant increase in osteoporosis risk among women participants with regular physical activity (HR 1.19; 95% CI 0.93–1.52). A more pro-inflammatory diet was significantly associated with higher osteoporosis risk in women. Given the similar magnitude of the hazards ratio, studies with sufficient numbers of men are warranted.

Targeting the Muscle-Bone Unit: Filling Two Needs with One Deed in the Treatment of Duchenne Muscular Dystrophy

PURPOSE OF REVIEW

In Duchenne muscular dystrophy (DMD), the progressive skeletal and cardiac muscle dysfunction and degeneration is accompanied by low bone mineral density and bone fragility. Glucocorticoids, which remain the standard of care for patients with DMD, increase the risk of developing osteoporosis. The scope of this review emphasizes the mutual cohesion and common signaling pathways between bone and skeletal muscle in DMD.

RECENT FINDINGS

The muscle-bone interactions involve bone-derived osteokines, muscle-derived myokines, and dual-origin cytokines that trigger common signaling pathways leading to fibrosis, inflammation, or protein synthesis/degradation. In particular, the triad RANK/RANKL/OPG including receptor activator of NF-kB (RANK), its ligand (RANKL), along with osteoprotegerin (OPG), regulates bone matrix modeling and remodeling pathways and contributes to muscle pathophysiology in DMD. This review discusses the importance of the muscle-bone unit in DMD and covers recent research aimed at determining the muscle-bone interactions that may eventually lead to the development of multifunctional and effective drugs for treating muscle and bone disorders regardless of the underlying genetic mutations in DMD.

The influence of thyroid disorders on bone density and biochemical markers of bone metabolism

Background Thyroid dysfunction, predominantly hyperthyroidism, has been previously linked to impaired bone mass density (BMD) and increased risk of fractures. On the other hand, data in the field of hypothyroidism (HT) are missing. The purpose of the present study was to investigate the impact of thyroid disorders on bone density serum and urine calcium (Ca) and phosphate (P) as well as serum osteocalcin and alkaline phosphatase and urine hydroxyproline in a series of post-menopausal women. Materials and methods The study was conducted in the Reproductive Endocrinology Outpatient Clinic of our hospital. A consecutive series of post-menopausal women was included, after excluding patients under hormone treatment (including levothyroxine supplementation) and those who received raloxifene, tamoxifen or tibolone during the study period as well as those who received treatment during the previous 12 months were excluded from the present study. Results Overall, 188 women were included in the present study. Among them, 143 women had normal thyroid function, 32 women had hyperthyroidism and 13 women had HT. Correlation of thyroid function indices with osteoporosis indices revealed statistically significant correlations between thyroxine (T4) and free triiodothyronine (T3) with T-, Z-scores and BMD. Logistic regression analysis concerning the impact of HT and hyperthyroidism on T-score, Z-score and bone mass density revealed that both pathological entities negatively affect bone health (p < 0.05). Conclusion The findings of our study suggest that not only hyperthyroidism, but also HT negatively affects BMD. Future studies should investigate this association and corroborate our findings.

Inflammageing: chronic inflammation in ageing, cardiovascular disease, and frailty

Most older individuals develop inflammageing, a condition characterized by elevated levels of blood inflammatory markers that carries high susceptibility to chronic morbidity, disability, frailty, and premature death. Potential mechanisms of inflammageing include genetic susceptibility, central obesity, increased gut permeability, changes to microbiota composition, cellular senescence, NLRP3 inflammasome activation, oxidative stress caused by dysfunctional mitochondria, immune cell dysregulation, and chronic infections. Inflammageing is a risk factor for cardiovascular diseases (CVDs), and clinical trials suggest that this association is causal. Inflammageing is also a risk factor for chronic kidney disease, diabetes mellitus, cancer, depression, dementia, and sarcopenia, but whether modulating inflammation beneficially affects the clinical course of non-CVD health problems is controversial. This uncertainty is an important issue to address because older patients with CVD are often affected by multimorbidity and frailty - which affect clinical manifestations, prognosis, and response to treatment - and are associated with inflammation by mechanisms similar to those in CVD. The hypothesis that inflammation affects CVD, multimorbidity, and frailty by inhibiting growth factors, increasing catabolism, and interfering with homeostatic signalling is supported by mechanistic studies but requires confirmation in humans. Whether early modulation of inflammageing prevents or delays the onset of cardiovascular frailty should be tested in clinical trials.

Interferon-Gamma-Mediated Osteoimmunology

Osteoimmunology is the interdiscipline that focuses on the relationship between the skeletal and immune systems. They are interconnected by shared signal pathways and cytokines. Interferon-gamma (IFN-γ) plays important roles in immune responses and bone metabolism. IFN-γ enhances macrophage activation and antigen presentation. It regulates antiviral and antibacterial immunity as well as signal transduction. IFN-γ can promote osteoblast differentiation and inhibit bone marrow adipocyte formation. IFN-γ plays dual role in osteoclasts depending on its stage. Furthermore, IFN-γ is an important pathogenetic factor in some immune-mediated bone diseases including rheumatoid arthritis, postmenopausal osteoporosis, and acquired immunodeficiency syndrome. This review will discuss the contradictory findings of IFN-γ in osteoimmunology and its clinical application potential.

Protective Effects of Selected Botanical Agents on Bone

Osteoporosis is a serious health problem affecting more than 200 million elderly people worldwide. The early symptoms of this disease are hardly detectable. It causes progressive bone loss, which ultimately renders the patients susceptible to fractures. Osteoporosis must be prevented because the associated fragility fractures result in high morbidity, mortality, and healthcare costs. Many plants used in herbal medicine contain bioactive compounds possessing skeletal protective effects. This paper explores the anti-osteoporotic properties of selected herbal plants, including their actions on osteoblasts (bone forming cells), osteoclasts (bone resorbing cells), and bone remodelling. Some of the herbal plant families included in this review are Berberidaceae, Fabaceae, Arecaceae, Labiatae, Simaroubaceaea, and Myrsinaceae. Their active constituents, mechanisms of action, and pharmaceutical applications were discussed. The literature shows that very few herbal plants have undergone human clinical trials to evaluate their pharmacological effects on bone to date. Therefore, more intensive research should be performed on these plants to validate their anti-osteoporotic properties so that they can complement the currently available conventional drugs in the battle against osteoporosis.

A Cross-Sectional Study of the Association between Autoantibodies and Qualitative Ultrasound Index of Bone in an Elderly Sample without Clinical Autoimmune Disease

Bone loss is characteristic of the ageing process and a common complication of many autoimmune diseases. Research has highlighted a potential role of autoantibodies in pathologic bone loss. The confounding effects of immunomodulatory drugs make it difficult to establish the contribution of autoantibodies amongst autoimmune disease sufferers. We attempted to examine the relationship between autoantibodies and bone mass in a population of 2812 elderly participants without clinical autoimmune disease. Serum samples were assayed for a panel of autoantibodies (anti-nuclear, extractable nuclear antigen, anti-neutrophil cytoplasmic, thyroid peroxidase, tissue transglutaminase, anti-cardiolipin, rheumatoid factor, and cyclic citrullinated peptide). Bone mass was measured using quantitative ultrasound (QUS) of the calcaneus. The relationship between each autoantibody and bone mass was determined using linear regression models. Anti-nuclear autoantibodies were the most prevalent, positive in approximately 11%, and borderline in roughly 23% of our sample. They were also the only autoantibody observed to be significantly associated with QUS index in the univariate analysis (n = 1628; r = -0.20; 95% CI: -0.40-0.00; p = 0.046). However, statistical significance was lost after adjustment for various other potential confounders. None of the other autoantibodies was associated with QUS index in either univariate or multivariate analysis. We are limited by the cross-sectional nature of the study and the low prevalence of autoantibodies in our nonclinical sample.

Lamins and bone disorders: current understanding and perspectives

Lamin A/C is a major constituent of the nuclear lamina implicated in a number of genetic diseases, collectively known as laminopathies. The most severe forms of laminopathies feature, among other symptoms, congenital scoliosis, osteoporosis, osteolysis or delayed cranial ossification.

Importantly, specific bone districts are typically affected in laminopathies. Spine is severely affected in LMNA-linked congenital muscular dystrophy. Mandible, terminal phalanges and clavicles undergo osteolytic processes in progeroid laminopathies and Restrictive Dermopathy, a lethal developmental laminopathy. This specificity suggests that lamin A/C regulates fine mechanisms of bone turnover, as supported by data showing that lamin A/C mutations activate non-canonical pathways of osteoclastogenesis, as the one dependent on TGF beta 2.

Here, we review current knowledge on laminopathies affecting bone and LMNA involvement in bone turnover and highlight lamin-dependent mechanisms causing bone disorders. This knowledge can be exploited to identify new therapeutic approaches not only for laminopathies, but also for other rare diseases featuring bone abnormalities.

The guiding role of bone metabolism test in osteoporosis treatment

Osteoporosis (OP) and osteoporotic fractures are becoming a serious health care issue in the world. Calcium and vitamin D are the basic treatment for osteoporosis. Nonetheless, they do not effectively reduce the incidences of fracture. Currently approved treatments for osteoporosis include selective estrogen receptor modulators (SERMs), bisphosphonates, denosumab, teriparatide, calcitonin and others. However, the appearance of some adverse effects including atypical fracture and breast cancer has limited long-term treatments above mentioned. Therefore, treatment decision should be made on an individual basis, taking into account the relative benefits and risks in different patients. Bone metabolism test helps to assess the patient's condition, which may ultimately lead to therapeutic options and better clinical outcomes.

Osteoporosis as an initial manifestation in a patient with Crohn's disease: A case report

The present case report details a rare case of osteoporosis as the initial manifestation of Crohn's disease (CD). A 43-year-old male was referred to the Second Xiangya Hospital of Central South University (Changsha, China) for further examination of low back pain (LBP) without digestive symptoms. Bone mineral density (BMD) analysis indicated osteoporosis, particularly in the lumbar spine. Endoscopy revealed an inflamed and strictured ileocecal valve with less inflammation in the ascending, transverse colon, sigmoid colon and rectum, compatible with CD, which was in accordance with the appearance of an abdominal computed tomography scan. Duodenal-balloon enteroscopy indicated segmental ulceration and stricture in the jejunum, in accordance with CD. The patient was diagnosed with CD following examination. It was suspected that osteoporosis may be an extra-intestinal manifestation of CD. Steroids and biological agents were prescribed in sequence. LBP and BMD rapidly improved following treatment, and inflammatory markers returned to normal after 1.5 years of treatment. According to this case, osteoporosis with unknown causes should be considered as a possible sign of small intestinal CD.