Heavy metals accumulation affects bone microarchitecture in osteoporotic patients

Association between multiple metal exposure and bone mineral density among Chinese adults

Previous studies about metal exposures and bone mineral density (BMD) have mainly focused on individual metals. The objective of this study was to explore the association of single and multiple metal exposures with BMD among Chinese adults. We recruited 2922 participants from Tongji Hospital in Wuhan, China. The urinary concentrations of 21 metals were measured by the inductively coupled plasma mass spectrometer. BMD was measured using dual-energy X-ray absorptiometry. We applied linear regression and Bayesian kernel machine regression (BKMR) to examine the association of single and multiple metal exposure with BMD, respectively. The linear regression model showed that cadmium (Cd) and strontium (Sr) were associated with lower BMD (all P-trend < 0.05). Compared with the lowest quantiles, the β (95% CI) of BMD in the highest quartile of Cd and Sr was - 0.032 (- 0.049, - 0.016) and - 0.033 (- 0.049, - 0.018), respectively. The BKMR results showed that co-exposure to 21 metals was negatively associated with BMD among the total participants and males. Our study suggested that exposure to multiple metals was negatively associated with BMD, particularly among males. More prospective studies are needed to identify these associations and reveal the underlying mechanisms.

Heavy Metal and Trace Element Status and Dietary Determinants in Children with Phenylketonuria

Background/Objectives: Heavy metals are a group of metals and metalloids that have a relatively high density. They can cause toxicity even at very low levels. Trace elements are required by all living organisms to maintain their normal growth, metabolism, and development. Oral intake is the main route of exposure to both heavy metals and trace elements. Phenylketonuria (PKU) is the most common amino acid metabolic disorder, and the best known treatment for patients requiring treatment is a phenylalanine (Phe)-restricted diet. The objective of the present study was to evaluate the plasma heavy metal levels, sources of exposure, changes in these levels according to dietary regimen, and trace element levels and their correlations with heavy metals in PKU patients. Methods: The study was conducted between July 2022 and January 2024 on 105 patients aged 2-6 years diagnosed with PKU. Results: The percentage of Pb levels in individuals in the upper quartile increased by 3.47 times (95% CI = 1.07-11.29) in those who consumed canned foods and 7.29 times (95% CI = 1.21-44.03) in those who consumed spring water. The percentage of As levels in the upper tertile increased by a factor of 7.26 (95% CI = 2.09-25.28) in individuals under four years of age and 8.17 times (95% CI = 2.13-31.27) in canned food users. The odds of having blood Cd levels in the upper tertile were 0.09 (95% CI = 0.01-0.96) for those being breastfed for 6-11 months compared to 0-5 months. Zn levels were lower (93.0 vs. 83.6 µg/dL, p = 0.008) in patients on a Phe-restricted diet. Conclusions: The present study did not find a relationship between heavy metal exposure and the dietary treatment status of patients with PKU. Our findings indicate that canned food consumption is a significant contributing factor to heavy metal exposure in PKU patients. Furthermore, our findings revealed a relationship between age, perception of economic level, breastfeeding, kitchen equipment, and water usage and the levels of certain heavy metals.

PMA-Zeolite: Chemistry and Diverse Medical Applications

Numerous scientific studies have been conducted in recent decades with the aim to study targeted application of zeolites in various industries, ecology, agronomy and medicine. The biggest advances, however, have been documented in medical and veterinary research of the natural zeolite, clinoptilolite. Although the exact biological mechanisms of action of the zeolite clinoptilolite are not completely elucidated, obtained results point to its antioxidative, immunomodulatory and detoxifying effects, the latter partially based on release of soluble and bioavailable silica forms from the surface material. The studied zeolite clinoptilolite materials have different geographical origins which confer to the physicochemical differences in the material. In addition, the production process of the material for oral applications differs between different producers which also accounts for different properties of the surface upon mechanical activation. Recently, a well-characterized zeolite clinoptilolite material, namely the PMA-zeolite, has been tested in different clinical applications and has shown potential as supportive therapy in inflammatory conditions, osteoporosis as well as during tumor chemotherapy. We accordingly present a comprehensive review of the PMA-zeolite effects in the clinical applications and discuss its probable mechanisms of effect in vivo.

SEC31a-ATG9a Interaction Mediates the Recruitment of COPII Vesicles for Autophagosome Formation

Autophagy plays an important role in determining stem-cell differentiation. During the osteogenic differentiation of mesenchymal stem cells (MSCs), autophagosome formation is upregulated but the reason is unknown. A long-standing quest in the autophagy field is to find the membrane origin of autophagosomes. In this study, cytoplasmic coat protein complex II (COPII) vesicles, endoplasmic reticulum-derived vesicles responsible for the transport of storage proteins to the Golgi, are demonstrated to be a critical source of osteoblastic autophagosomal membrane. A significant correlation between the number of COPII vesicle and the autophagy level is identified in the rat bone tissues. Disruption of COPII vesicles restrained osteogenesis and decreased the number and size of autophagosomes. SEC31a (an outer coat protein of COPII vesicle) is found to be vital to regulate COPII vesicle-dependent autophagosome formation via interacting with ATG9a of autophagosomal seed vesicles. The interference of Sec31a inhibited autophagosome formation and osteogenesis in vitro and in vivo. These results identified a novel mechanism of autophagosome formation in osteogenic differentiation of stem cells and identified SEC31a as a critical protein that mediates the interplay between COPII and ATG9a vesicles. These findings broaden the understanding of the regulatory mechanism in the osteogenic differentiation of MSCs.

The influence of adult urine lead exposure on bone mineral densit: NHANES 2015-2018

Introduction

Previous studies have indicated that exposure to heavy metals related to bone health is primarily limited to some common harmful metals, and the impact of lead has not been fully understood. This study aims to explore the relationship between urine lead exposure and bone density.

Methods

1,310 adults were included from the NHANES database (2015-2018), and through generalized linear regression analysis and constrained cubic spline models, the association between lead levels and total bone density as well as lumbar spine bone density was explored. The study also examined the impact of combined exposure to lead and cadmium on bone density.

Results and conclusions

Urinary lead levels were significantly negatively correlated with total bone mineral density (β: -0.015; 95%CI: -0.024, -0.007) and lumbar spine bone mineral density (β: -0.019; 95%CI: -0.031, -0.006). Compared to the lowest three quartiles of lead levels, the adjusted odds ratios for T3 changes in total bone mineral density and lumbar spine bone mineral density were 0.974 (95%CI: 0.959, 0.990) and 0.967 (95%CI: 0.943, 0.991), indicating a significant negative trend. Further analysis with constrained cubic spline models revealed a non-linear decreasing relationship between urinary lead and total bone mineral density as well as lumbar spine bone mineral density. Stratified analyses suggested that the relationship between urinary lead levels and bone mineral density might be significantly influenced by age, while gender showed no significant impact on the relationship. Moreover, combined exposure to lead and cadmium was found to be associated with decreased bone mineral density, emphasizing the potential synergistic effects between lead and cadmium on bone health. However, the specific mechanisms of lead and its effects on different populations require further comprehensive research. This study provides valuable insights for further exploration and development of relevant public health policies.

Impact of the environmental pollution on cardiovascular diseases: From epidemiological to molecular evidence

Environmental pollution poses a significant threat to human health, particularly concerning its impact on cardiovascular diseases (CVDs). This review synthesizes epidemiological and molecular evidence to elucidate the intricate relationship between environmental pollutants and CVDs. Epidemiological studies highlight the association between exposure to air, water, and soil pollutants and increased CVD risk, including hypertension, coronary artery disease, and stroke. Furthermore, molecular investigations unravel the underlying mechanisms linking pollutant exposure to CVD pathogenesis, such as oxidative stress, inflammation, endothelial dysfunction, and autonomic imbalance. Understanding these molecular pathways is crucial for developing targeted interventions and policy strategies to mitigate the adverse effects of environmental pollution on cardiovascular health. By integrating epidemiological and molecular evidence, this review provides insights into the complex interplay between environmental factors and CVDs, emphasizing the urgent need for comprehensive preventive measures and environmental policies to safeguard public health.

Metals accumulation affects bone and muscle in osteoporotic patients: A pilot study

Osteoporosis is the most common bone disease, characterized by decreased bone mineral density (BMD) and often associated to decreased muscle mass and function. Metal exposure plays a role in the pathophysiology of osteoporosis and affects also muscle quality. The aim of this study was to assess the association between metal levels in bone and muscle samples and the degeneration of these tissues. A total of 58 subjects (30 male and 28 female) was enrolled and classified in osteoporotic (OP, n = 8), osteopenic (Ope, n = 30) and healthy (CTR, n = 20) subjects, according to BMD measures. Femoral head bone samples and vastus lateralis muscle samples were collected during hip arthroplasty surgeries. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis showed increased levels of Al, Cd and Pb in OP and Ope bone tissue compared to CTR subjects (p = 0.04, p = 0.005 and p = 0.01, respectively). Whereas, increased levels of Co, Cd and Pb were measured in OP and Ope muscle tissues, compared to CTRs (p < 0.001, p = 0.02 and p = 0.01, respectively). In addition, Al, Cd and Pb levels in bone and Cd and Co levels in muscle were negatively correlated with BMD. A negative association among Co, Cd, Cr and Hg levels and muscle fibers diameter was also observed in muscle tissues. This study assessed that metal exposure can affects bone and muscle tissue quality and may contribute to the onset and progression of musculoskeletal diseases such as osteoporosis. Therefore, it is important to implement metal exposure assessment and their impact on disease development, in order to manage and prevent metal accumulation effects on bone and muscle quality.

The impact of toxic metal bioaccumulation on colorectal cancer: Unravelling the unexplored connection

Colorectal cancer is a major public health concern, with increasing incidence and mortality rates worldwide. Environmental factors, including exposure to toxic metals, such as lead, chromium, cadmium, aluminium, copper, arsenic and mercury, have been suggested to play a significant role in the development and progression of this neoplasia. In particular, the bioaccumulation of toxic metals can play a significant role in colorectal cancer by regulating biological phenomenon associated to both cancer occurrence and progression, such as cell death and proliferation. Also, frequently these metals can induce DNA mutations in well-known oncogenes. This review provides a critical analysis of the current evidence, highlighting the need for further research to fully grasp the complex interplay between toxic metal bioaccumulation and colorectal cancer. Understanding the contribution of toxic metals to colorectal cancer occurrence and progression is essential for the development of targeted preventive strategies and social interventions, with the ultimate goal of reducing the burden of this disease.

A comprehensive review on environmental pollutants and osteoporosis: Insights into molecular pathways

A significant problem that has an impact on community wellbeing is environmental pollution. Environmental pollution due to air, water, or soil pollutants might pose a severe risk to global health, necessitating intense scientific effort. Osteoporosis is a common chronic condition with substantial clinical implications on mortality, morbidity, and quality of life. It is closely linked to bone fractures. Worldwide, osteoporosis affects around 200 million people, and every year, there are almost 9 million fractures. There is evidence that certain environmental factors may increase the risk of osteoporosis in addition to traditional risk factors. It is crucial to understand the molecular mechanisms at play because there is a connection between osteoporosis and exposure to environmental pollutants such as heavy metals, air pollutants, endocrine disruptors, metal ions and trace elements. Hence, in this scoping review, we explore potential explanations for the link between pollutants and bone deterioration through deep insights into molecular pathways. Understanding and recognizing these pollutants as modifiable risk factors for osteoporosis would possibly help to enhance environmental policy thereby aiding in the improvement of bone health and improving patient quality of life.

Use of scanning electron microscopy and energy dispersive X-ray for urine analysis: A preliminary investigation

Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) are powerful tools to study the ultrastructure of numerous specimens and to determine their elemental composition, respectively. However, results have not yet been reported on their application to urine samples in routine clinical laboratory practice. Herein we investigate urine sediment by using SEM and EDX to detect and identify different urine components. A total of 206 urine samples from patients with and without urinary tract infections were analyzed using SEM and EDX. Microorganisms, crystals, epithelial cells, leukocytes, and erythrocytes were targeted in urine sediment samples. The identification of urine components was based on their morphology, size, contrast, and elemental composition. SEM-analysis allowed us to identify and classify microorganisms in urine sediments into the categories of gram-negative bacilli, cluster cocci, chain cocci, gram-negative bacilli, gram-positive bacilli, and yeasts. In addition, various types of epithelial cells such as renal, transitional, and squamous epithelial cells were found. Furthermore, leukocytes and erythrocytes were well identified, with the detection of various morphological forms of erythrocytes, such as dysmorphic and isomorphic erythrocytes. Using SEM-EDX analysis, calcium oxalate was the most frequently-identified crystal (92.0%), with prominent peaks of C, O, and Ca elements, followed by struvite (6%), with peaks of Mg, P, O, and N. These preliminary data suggest that the two complementary SEM-EDX analyses can be used to detect and identify microorganisms and crystals in urine samples. Further studies are still needed to apply SEM-EDX to urine sediment analysis. SEM-EDX analyses provided comparative results with the routine results, with accurate identification, high resolution and deep focus compared to the routine urinalysis SEM-analysis allowed us to identify and classify microorganisms in urine sediments into the categories of gram-negative bacilli, cluster cocci, chain cocci, gram-negative bacilli, gram-positive bacilli and yeasts. SEM-EDX analysis enabled the accurate identification of crystals based on both morphology and elemental composition.

Metallosis after Hip Arthroplasty Damages Skeletal Muscle: A Case Report

Good musculoskeletal quality dramatically influences the outcome of an arthroplasty operation in geriatric patients, as well as is a key element for optimal osseointegration. In this context, metallosis is a complication associated with the type of prosthesis used, as implants with a chromium-cobalt interface are known to alter the bone microarchitecture and reduce the ratio of muscle to fat, resulting in lipid accumulation. Therefore, the aim of our study was to investigate possible muscle changes by histological, morphometric, and immunohistochemical analyses in a patient undergoing hip replacement revision with elevated blood and urinary concentrations of chromium and cobalt. Interestingly, the muscle tissue showed significant structural changes and a massive infiltration of adipose tissue between muscle fibers in association with an altered expression pattern of important biomarkers of musculoskeletal health and oxidative stress, such as myostatin and NADPH Oxidase 4. Overall, our results confirm the very serious impact of metallosis on musculoskeletal health, suggesting the need for further studies to adopt a diagnostic approach to identify the cause of metallosis early and eliminate it as part of the prosthesis revision surgery.

METTL14 represses osteoclast formation to ameliorate osteoporosis via enhancing GPX4 mRNA stability

Excessive bone resorption by osteoclasts results in the development of multiple bone disorders including osteoporosis. This study aimed to explore the biological function of methyltransferase-like14 (METTL14) in osteoclast formation, as well as its related mechanisms. Expression levels of METTL14, GPX4 and osteoclast-related proteins TRAP, NFATc1, c-Fos were detected by qRT-PCR and Western blotting. The osteoporosis model was established in mice by bilateral ovariectomy (OVX). Bone histomorphology was determined by micro-CT and H&E staining. NFATc1 expression in bone tissues was determined by immunohistochemical staining. Proliferation of primary bone marrow macrophages cells (BMMs) was assessed by MTT assay. Osteoclast formation was observed by TRAP staining. The regulatory mechanism was evaluated by RNA methylation quantification assay, MeRIP-qPCR, dual luciferase reporter assay, and RIP, respectively. METTL14 was down-regulated in the serum samples of postmenopausal osteoporotic women, which was positively associated with bone mineral density (BMD). Osteoclast formation was promoted in OVX-treated METTL14+/- mice as compared with wild-type littermates. Conversely, METTL14 overexpression repressed RANKL-induced osteoclast differentiation of BMMs. Mechanistically, METTL14-mediated m6A modification post-transcriptionally stabilized glutathione peroxidase 4 (GPX4), with the assistance of Hu-Antigen R (HuR). Finally, GPX4 depletion-mediated osteoclast formation in BMMs could be counteracted by METTL14 or HuR overexpression. Collectively, METTL14 inhibits osteoclastogenesis and bone resorption via enhancing GPX4 stability through an m6A-HuR dependent mechanism. Therefore, targeting METTL14 might be a novel promising treatment strategy for osteoporosis.

Ascorbic acid reduces Ropivacaine-induced myotoxicity in cultured human osteoporotic skeletal muscle cells

BACKGROUND

Osteoporosis is a worldwide health issue. Loss of bone mass is a potential risk factor for fragility fractures, and osteoporotic fractures place a considerable burden on society. Bone and muscle represent a functional unit in which the two tissues are intimately interconnected. Ropivacaine is a potent local anesthetic used in clinical practice for intraoperative anesthesia and postoperative pain management, in particular for hip surgery. When injected, Ropivacaine can diffuse locally through, in particular in surrounding skeletal muscle tissue, causing dose-dependent cytotoxicity, oxidative stress and myogenesis impairment. Based on those evidences, we focused our attention on Ropivacaine-induced cytotoxicity on cultured human myoblasts.

METHODS

Primary human myoblasts and myotubes from healthy subjects, osteoarthritic and osteoporotic patients (OP) were cultured in the presence of Ropivacaine. In some experiments, ascorbic acid (AsA) was added as a potent antioxidant agent. Cell viability and ROS levels were evaluated to investigate the myotoxic activity and Real-Time PCR and Western blot analysis carried out to investigate the expression of proliferation and myogenic markers.

RESULTS

A dose-dependent decrease of cell viability was observed after Ropivacaine exposure in both OP myoblasts and myotubes cultures, whereas those effects were not observed in the presence of Propofol, a general anesthetic. The adding of AsA reduced Ropivacaine negative effects in OP myoblast cultures. In addition, Ropivacaine exposure also increased ROS levels and upregulated Nox4 expression, an enzyme primarily implicated in skeletal muscle ROS generation. AsA treatment counteracted the oxidant activity of Ropivacaine and partially restored the basal condition in cultures. Positive myogenic markers, such as MyoD and Myf5, were downregulated by Ropivacaine exposure, whereas myostatin, a negative regulator of muscle growth and differentiation, was upregulated. The phenotypic deregulation of myogenic controllers in the presence of Ropivacaine was counteracted by AsA treatment.

CONCLUSIONS

Our findings highlight the oxidative stress-mediated myotoxic effect of Ropivacaine on human skeletal muscle tissue cell cultures, and suggest treatment with AsA as valid strategy to mitigate its negative effects and allowing an ameliorated functional skeletal muscle recovery in patients undergoing hip replacement surgery for osteoporotic bone fracture.

Plasma heavy metal levels correlate with deregulated gene expression of detoxifying enzymes in osteoporotic patients

Heavy metal levels appear to be associated with low bone mineral density (BMD) and the consequent osteoporosis risk, but the relationship with the disease has not been clearly defined. The altered expression pattern of numerous genes, including detoxifying genes, seems to play a pivotal role in this context, leading to increased susceptibility to several diseases, including osteoporosis. The purpose of this study is to analyse circulating heavy metals levels and the expression of detoxifying genes in osteoporotic patients (OPs, n = 31), compared with healthy subjects (CTRs, n = 32). Heavy metals concentration in plasma samples was determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), and the subsequent expression analysis of NAD(P)H quinone dehydrogenase 1 (NQO1), Catalase (CAT), and Metallothionein 1E (MT1E) genes in Peripheral Blood Mononuclear Cells (PBMCs) was assessed by real-time polymerase chain reaction (qRT-PCR). Copper (Cu), mercury (Hg), molybdenum (Mo) and lead (Pb) were found to be significantly higher in the plasma of OPs compared to CTRs. Analysis of the expression levels of detoxifying genes showed a significant decrease in CAT and MT1E in OP group. In addition, Cu correlated positively with the expression levels of both CAT and MT1E in CTRs group and MT1E in OPs. This study shows an increased circulating concentration of certain metals combined with an altered expression pattern of detoxifying genes in OPs, highlighting a novel aspect to be investigated in order to better characterize the role of metals in the pathogenesis of osteoporosis.

Nutraceuticals as Alternative Approach against Cadmium-Induced Kidney Damage: A Narrative Review

Cadmium (Cd) represents a public health risk due to its non-biodegradability and long biological half-life. The main target of Cd is the kidney, where it accumulates. In the present narrative review, we assessed experimental and clinical data dealing with the mechanisms of kidney morphological and functional damage caused by Cd and the state of the art about possible therapeutic managements. Intriguingly, skeleton fragility related to Cd exposure has been demonstrated to be induced both by a direct Cd toxic effect on bone mineralization and by renal failure. Our team and other research groups studied the possible pathophysiological molecular pathways induced by Cd, such as lipid peroxidation, inflammation, programmed cell death, and hormonal kidney discrepancy, that, through further molecular crosstalk, trigger serious glomerular and tubular injury, leading to chronic kidney disease (CKD). Moreover, CKD is associated with the presence of dysbiosis, and the results of recent studies have confirmed the altered composition and functions of the gut microbial communities in CKD. Therefore, as recent knowledge demonstrates a strong connection between diet, food components, and CKD management, and also taking into account that gut microbiota are very sensitive to these biological factors and environmental pollutants, nutraceuticals, mainly present in foods typical of the Mediterranean diet, can be considered a safe therapeutic strategy in Cd-induced kidney damage and, accordingly, could help in the prevention and treatment of CKD.

Association between dietary intake of α-tocopherol and cadmium related osteoporosis in population ≥ 50 years

INTRODUCTION

To analyze the association between α-tocopherol intake and cadmium (Cd) exposure and osteoporosis in population ≥ 50 years.

MATERIALS AND METHODS

Sociodemographic data, physical examination, and laboratory indicators including serum Cd level and dietary α-tocopherol intake of 8459 participants were extracted from the National Health and Nutrition Examination Survey (NHANES) database in this cross-sectional study. The associations between α-tocopherol intake, serum Cd levels and osteoporosis were evaluated using univariate and multivariate logistic regression analyses, with the estimated value (β), odds ratios (ORs) and 95% confidence intervals (CIs). We further explored the impact of α-tocopherol intake on Cd exposure and the bone mineral density (BMD) in total femur and femur neck.

RESULTS

A total of 543 old adults suffered from osteoporosis. The serum Cd level (0.52 μg/L vs. 0.37 μg/L) and α-tocopherol intake (5.28 mg vs. 6.50 mg) were statistical different in osteoporosis group and non-osteoporosis group, respectively. High level of Cd exposure was related to the increased risk of osteoporosis [OR = 1.60, 95% CI (1.15-2.21)]. In the total femur, α-tocopherol intake may improve the loss of BMD that associated with Cd exposure [β = - 0.047, P = 0.037]. Moreover, high α-tocopherol intake combined with low Cd exposure [OR = 0.54, 95% CI (0.36-0.81)] was linked to the decreased risk of osteoporosis comparing with low α-tocopherol intake combined with high Cd exposure.

CONCLUSION

High α-tocopherol intake may improve the Cd-related osteoporosis and loss of BMD that could provide some dietary reference for prevention of osteoporosis in population ≥ 50 years old.

Regulatory mechanisms of microRNAs in endocrine disorders and their therapeutic potential

MicroRNAs (miRNAs) are small endogenous non-coding RNA molecules capable of regulating gene expression at the post-transcriptional level either by translational inhibition or mRNA degradation and have recently been importantly related to the diagnosis and prognosis of the most relevant endocrine disorders. The endocrine system comprises various highly vascularized ductless organs regulating metabolism, growth and development, and sexual function. Endocrine disorders constitute the fifth principal cause of death worldwide, and they are considered a significant public health problem due to their long-term effects and negative impact on the patient's quality of life. Over the last few years, miRNAs have been discovered to regulate various biological processes associated with endocrine disorders, which could be advantageous in developing new diagnostic and therapeutic tools. The present review aims to provide an overview of the most recent and significant information regarding the regulatory mechanism of miRNAs during the development of the most relevant endocrine disorders, including diabetes mellitus, thyroid diseases, osteoporosis, pituitary tumors, Cushing's syndrome, adrenal insufficiency and multiple endocrine neoplasia, and their potential implications as disease biomarkers.

Recent advances in the application of ionomics in metabolic diseases

Trace elements and minerals play a significant role in human health and diseases. In recent years, ionomics has been rapidly and widely applied to explore the distribution, regulation, and crosstalk of different elements in various physiological and pathological processes. On the basis of multi-elemental analytical techniques and bioinformatics methods, it is possible to elucidate the relationship between the metabolism and homeostasis of diverse elements and common diseases. The current review aims to provide an overview of recent advances in the application of ionomics in metabolic disease research. We mainly focuses on the studies about ionomic or multi-elemental profiling of different biological samples for several major types of metabolic diseases, such as diabetes mellitus, obesity, and metabolic syndrome, which reveal distinct and dynamic patterns of ion contents and their potential benefits in the detection and prognosis of these illnesses. Accumulation of copper, selenium, and environmental toxic metals as well as deficiency of zinc and magnesium appear to be the most significant risk factors for the majority of metabolic diseases, suggesting that imbalance of these elements may be involved in the pathogenesis of these diseases. Moreover, each type of metabolic diseases has shown a relatively unique distribution of ions in biofluids and hair/nails from patients, which might serve as potential indicators for the respective disease. Overall, ionomics not only improves our understanding of the association between elemental dyshomeostasis and the development of metabolic disease but also assists in the identification of new potential diagnostic and prognostic markers in translational medicine.

Using Peromyscus leucopus as a biomonitor to determine the impact of heavy metal exposure on the kidney and bone mineral density: results from the Tar Creek Superfund Site

Background

Human population growth and industrialization contribute to increased pollution of wildlife habitats. Heavy metal exposure from industrial and environmental sources is still a threat to public health, increasing disease susceptibility. In this study, I investigated the effects of heavy metals (cadmium (Cd), lead (Pb), and zinc (Zn)) on kidney and bone density.

Objective

This study aims to determine the concentrations of Cd, Pb, and Zn in soil and compare them to the levels of the same metals in Peromyscus leucopus kidney tissue. Furthermore, the study seeks to investigate the impact of heavy metals on bone density and fragility using the fourth lumbar vertebra (L4) of P. leucopus.

Methods

Cd, Pb, and Zn concentrations in soil specimens collected from Tar Creek Superfund Site (TCSFS), Beaver Creek (BC), and two reference sites (Oologah Wildlife Management Area (OWMA) and Sequoyah National Wildlife Refuge (SNWR)). Heavy metal concentrations were analyzed using inductively coupled plasma-mass spectroscopy (ICP-MS). Micro-computed tomography (µCT) was used to assess the influence of heavy metals on bone fragility and density.

Results

On the one hand, soil samples revealed that Pb is the most common pollutant in the sediment at all of the investigated sites (the highest contaminated site with Pb was TCSFS). Pb levels in the soil of TCSFS, BC, OWMA, and SNWR were found to be 1,132 ± 278, 6.4 ± 1.1, and 2.3 ± 0.3 mg/kg in the soil of TCSFS, BC and OWMA and SNWR, respectively. This is consistent with the fact that Pb is one of the less mobile heavy metals, causing its compounds to persist in soils and sediments and being barely influenced by microbial decomposition. On the other hand, the kidney samples revealed greater Cd levels, even higher than those found in the soil samples from the OWMA and SNWR sites. Cd concentrations in the kidney specimens were found to be 4.62 ± 0.71, 0.53 ± 0.08, and 0.53 ± 0.06 µg/kg, respectively. In addition, micro-CT analysis of L4 from TCSFS showed significant Pearson's correlation coefficients between Cd concentrations and trabecular bone number (-0.67, P ≤ 0.05) and trabecular separation (0.72, P ≤ 0.05). The results showed no correlation between bone parameters and metal concentrations at reference sites. This study is one of the few that aims to employ bone architecture as an endpoint in the field of biomonitoring. Furthermore, this study confirmed some earlier research by demonstrating substantial levels of heavy metal contamination in soil samples, kidney samples, and P. leucopus L4 trabecular bone separations from TCSFS. Moreover, this is the first study to record information regarding bone microarchitecture parameters in P. leucopus in North America.

In utero and lactational exposure to methylmercury elicits physical-chemical and morphological damages in the alveolar bone of offspring rats: The first toxicological findings

Methylmercury (MeHg) is the most common organic form of mercury (Hg) that humans are exposed and is considered an environmental pollutant. Several populations that live in endemic regions of MeHg exposure are subject to the toxicant for long periods, including pregnant women and children, causing damage to several organs during early periods of development. Alveolar bone is an essential structure for the oral cavity, responsible for supporting teeth and masticatory forces. However, evidence on the effects of MeHg on alveolar bone and the intrauterine and lactation period is lacking. Thus, this study aimed to investigate the effects of MeHg exposure during gestation and lactation on the developing alveolar bone of offspring rats after maternal exposure. Dams were exposed during 41 days of pregnancy and lactation, and the mandibles of the offspring were collected. The alveolar bone was analyzed by Fourier Transform Infrared Spectroscopy to evaluate the physicochemical composition; by Scanning Electron Microscopy for ultrastructural evaluation; by histopathological, histochemical, and morphometric for tissue analyses. In addition, bone quality was assessed by X-ray microtomography. MeHg exposure altered the mineral composition and caused histological damage associated with a lower quantity and thickness of bone trabeculae, as well as reduced osteocyte density and collagen fiber content. A reduction in trabecular thickness and bone volume and an increase in trabecular spaces were observed and were associated with anatomical compromise of the vertical bone dimensions. Thus, the results suggest that the developing alveolar bone is susceptible to the toxic effects of MeHg when organisms are exposed during intrauterine and lactation periods. From a translational perspective, these changes in the alveolar bone can help us understand possible abnormalities induced by toxic metals and highlight the need for care for structures other than those already seen as targets for damage triggered by environmental MeHg exposure.

Proximity to major roads and the incidence of osteoporotic fractures in elderly women: The BONE study in Beijing

Background

There is growing evidence to suggest that living near major roads (and suffering from the air pollution of urban streets) can have an adverse effect on bone health. However, little is known about its relationship to fractures caused by osteoporosis.

Objective

This study was designed to investigate the relationship between residents living near major roads and the incidence of osteoporotic fractures.

Methods

A retrospective cohort of 529 subjects was established based on community populations in older women aged 65-91. All participants lived in Beijing between September 27, 2007 and September 26, 2017. The distance between the residential sites of the subjects and the main roads was determined by the authors. Osteoporotic fracture diagnosis was based on medical histories and imaging examinations (DXA and X-rays). The Cox proportional hazard model was used to assess the association between traffic proximity and osteoporotic fractures, with suitable adjustments for individual and background factors.

Results

The age range of all participants was 65-91 years, with an average age of 75.8 years (and a standard deviation 6.8 years). Of these, 19 (3.59%) suffered from diabetes, and 48 (9%) had hypertension; 85 (14%) families had annual incomes below US $30,000 and 402 (76%) had received a secondary school education or higher. Nearly 25% of people lived within 50 m of a main road, while 50% lived within 300 m. Between 2007 and 2017, a total of 96 osteoporotic fractures were observed. For people living <50 m from a main road, the adjusted hazard ratio (HR) for osteoporotic fractures was 2.509 (95% CI 1.345-4.680), while it was 1.830 (95% CI 1.029-3.255) for those living at a distance of 50-300 m from a main road vs. those living further than 300 m away.

Conclusion

In this community-based cohort, living near a major road was associated with a higher incidence of osteoporotic fractures.

Concentration of Selected Macronutrients and Toxic Elements in the Blood in Relation to Pain Severity and Hydrogen Magnetic Resonance Spectroscopy in People with Osteoarthritis of the Spine

Macronutrients and toxic elements may play an important role in the pathogenesis of osteoarthritis of the spine. The objective of this study was to evaluate the relationship between the concentrations of Ca, Mg, Pb, Cd and Hg in blood with the results of hydrogen magnetic resonance spectroscopy and the severity of pain. Patients with osteoarthritis of the spine (n = 90) and control subjects (n = 40) were studied. The concentrations of mineral components in blood were determined by atomic absorption spectrometry (ASA). Spinal pain severity was assessed using the Visual Analog Scale (VAS). Hydrogen magnetic resonance spectroscopy (¹H-MRS) was used to determine the fat/water ratio in the bodies of L1, L5 and the L4/5 intervertebral disc. The median concentration of Mg in the serum of subjects with spinal degenerative disease was significantly lower (p < 0.001) than that in healthy subjects. The median concentration of Cd in the blood of subjects with osteoarthritis of the spine was significantly higher (p < 0.05) than that in the control group. Significantly lower (p < 0.05) median molar ratios of Ca to Cd and Pb as well as Mg to Pb and Cd were observed among patients with osteoarthritis of the spine. Significant differences (p < 0.05) were observed in the value of the fat/water ratio in selected spinal structures, depending on normal or abnormal serum Ca and Mg concentrations. The study showed some abnormal macronutrient concentrations, as well as disturbed ratios of beneficial elements to toxic elements in the blood of people with osteoarthritis of the spine.

Effect of cadmium on Rho GTPases signal transduction during osteoclast differentiation

Osteoclasts are the key target cells for cadmium (Cd)-induced bone metabolism diseases, while Rho GTPases play an important role in osteoclast differentiation and bone resorption. To identify new therapeutic targets of Cd-induced bone diseases; we evaluated signal transduction through Rho GTPases during osteoclast differentiation under the influence of Cd. In osteoclastic precursor cells, 10 nM Cd induced pseudopodia stretching, promoted cell migration, upregulated the levels of Cdc42, and RhoQ mRNAs and downstream Rho-associated coiled-coil kinase 1 (ROCK1) and ROCK2 proteins, and downregulated the actin-related protein 2/3 (ARP2/3) levels. Cd at 2 and 5 μM shortened the pseudopodia, inhibited cell migration, and decreased ROCK1, ROCK2, and ARP2/3 protein levels; Cd at 5 μM also reduced the mRNA expression levels of Rac1, Rac2, and RhoU mRNAs and decreased the level of phosphorylated (p)-cofilin. In osteoclasts, 10 nM Cd induced the formation of sealing zones, slightly upregulated Cdc42 mRNA levels and ROCK2 and ARP2/3 protein levels and significantly reduced p-cofilin levels. Cd at 2 μM and 5 μM Cd blocked the fusion of precursor cells; and 5 μM Cd downregulated the expression levels of RhoB, Rac1, Rac3, and RhoU mRNAs, and ROCK1, p-cofilin and ARP2/3 protein levels, significantly. In vivo, Cd (at 5 or 25 mg/L) increased the levels of key proteins RhoA, Rac1/2/3, Cdc42, and RhoU and their mRNAs in bone marrow cells. In summary, the results suggested that Cd affected the differentiation process of osteoclast and altered the expression of several Rho GTPases, which might be crucial targets of Cd during the differentiation of osteoclasts.

Aluminum intake in the neonatal phase disrupts endochondral ossification in rodents

OBJECTIVE

This study evaluated the effects of aluminum (Al) intake on endochondral ossification during the neonatal phase.

METHOD

Twelve male newborn Gerbils (Meriones unguiculatus) were randomly divided into control (C) and aluminum (Al) groups (n = 6 animals/group). From the 1st to 15th day of life, gerbils received an AlCl₃ solution (10 mg/kg/day) via gavage. The control group received only the saline solution. On the 16th day, their tibias were processed for paraffin embedding and were submitted to histomorphometric, histochemical, and immunohistochemical analyses.

RESULTS

In the epiphyseal cartilage Al did not affect the proteoglycan content or cell proliferation; however, it increased matrix metalloprotease-2 (MMP-2) immunostaining and the hypertrophic layer thickness. In bone, Al decreased trabeculae number, trabecular width, cortical bone width, and proliferation. Furthermore, the relative frequency of bone matrix and fibrillar collagen decreased 3.9% and 16.2%, respectively. The number of osteoclasts and osteocalcin digital optical density (D.O.D) remained the same.

CONCLUSION

The results suggest that Al intake during the neonatal period impairs endochondral ossification by affecting epiphyseal cartilage and bone architecture.

Biological aging mediates the associations between urinary metals and osteoarthritis among U.S. adults

BACKGROUND

Osteoarthritis (OA) is a worldwide public health concern, mainly afflicting older adults. Although the etiology of OA remains unclear, environmental factors are increasingly considered as non-negligible risk factors. This study aims to evaluate the associations of urinary metals with OA risk and the mediated effect of biological aging.

METHODS

Nine urinary metal concentrations were detected among 12,584 U.S. adults based on the National Health and Nutrition Examination Survey (NHANES), including barium (Ba), cadmium (Cd), cobalt (Co), cesium (Cs), molybdenum (Mo), lead (Pb), antimony (Sb), thallium (Tl), and uranium (Tu). Multivariable logistic regression and weighted quantile sum (WQS) regression were used to explore the associations of single metal and mixed metals with OA risk, respectively. Furthermore, biological aging was measured from different perspectives, including cell senescence (telomere length) and whole-body aging (phenotypic age and biological age). Mediation analyses were conducted to investigate the mediated effects of aging on the associations of metals with OA risk.

RESULTS

In the single-exposure model, Cd, Co, and Cs were identified to be positively associated with OA risk, with odds ratios (OR) ranging from 1.48 to 1.64 (all P < 0.05). Mixed-exposure analyses showed consistent associations (OR 1.23, 95%CI 1.10 to 1.37) and highlighted that Cd, Co, and Cs were responsible for the outcomes. Additionally, Cd, Co, Cs, Pb, and Tl were positively associated with biological aging markers, while all biological aging markers had significant associations with OA risk. Further mediation analyses showed that the associations of single metal (mainly Cd and Cs) and mixed metals with OA risk parallelly mediated by the above biological aging markers, with the proportion of mediation ranging from 16.89 to 69.39% (all P < 0.05). Moreover, such associations were also serially mediated through telomere length-biological age path and telomere length-phenotypic age path (the proportion of mediation: 4.17-11.67%), indicating that metals accelerated cell senescence to lead to whole-body aging and finally aggravated OA progress.

CONCLUSIONS

These findings suggested that exposure to metals increased OA risk, which was possibly and partly mediated by biological aging.

Associations between Plasma Folate and Vitamin B12, Blood Lead, and Bone Mineral Density among Adults and Elderly Who Received a Health Examination

This study hypothesized that plasma folate and vitamin B₁₂ levels modified the association between blood lead and cadmium and total urinary arsenic levels and bone loss. A total of 447 study subjects who received a physical examination at the Wanfang Hospital Medical Center were recruited. Bone loss was defined as a calcaneus bone mineral density T-score less than -1. Blood cadmium and lead concentrations were measured by ICP-MS. Urinary arsenic species were determined using HPLC-HG-AAS. A SimulTRAC-SNB radioassay was used to measure plasma folate, vitamin B₁₂, and homocysteine levels. Total urinary arsenic and blood lead concentration were positively correlated with the odds ratio (OR) for bone loss in a dose-response manner. The OR and 95% confidence interval (CI) for bone loss in participants with blood lead concentrations > 56.14 versus ≤33.82 μg/dL were 1.82 and 1.10-3.01. No correlation between plasma folate and vitamin B₁₂ levels alone and bone loss was observed. However, this study is the first observational study to find that blood lead concentrations tend to increase the OR of bone loss in a low plasma folate and plasma vitamin B₁₂ group with multivariate ORs (95% CI) of 2.44 (0.85-6.96).

Risk Factors Analysis of Bone Mineral Density Based on Lasso and Quantile Regression in America during 2015-2018

This study aimed to explore the risk factors of bone mineral density (BMD) in American residents and further analyse the extent of effects, to provide preventive guidance for maintenance of bone health. A cross-sectional study analysis was carried out in this study, of which data validity was identified and ethics approval was exempted based on the National Health and Nutrition Examination Survey (NHANES) database. Candidates' demographics, physical examination, laboratory indicators and part of questionnaire information were collected and merged from NHANES in 2015-2016 and 2017-2018. The least absolute shrinkage selection operator (lasso) was used to select initial variables with "glmnet" package of R, quantile regression model to analyze influence factors of BMD and their effects in different sites with "qreg" code in Stata. Among 2937 candidates, 17 covariates were selected by lasso regression (λ = 0.00032) in left arm BMD, with 16 covariates in left leg BMD (λ = 0.00052) and 14 covariates in total BMD (λ = 0.00065). Quantile regression results displayed several factors with different coefficients in separate sites and quantiles: gender, age, educational status, race, high-density lipoprotein (HDL), total cholesterol (TC), lead, manganese, ethyl mercury, smoking, alcohol use and body mass index (BMI) (p < 0.05). We constructed robust regression models to conclude that some demographic characteristics, nutritional factors (especially lipid levels, heavy metals) and unhealthy behaviors affected BMD in varying degrees. Gender and race differences, Low-fat food intake and low exposure to heavy metals (mostly lead, manganese and mercury) should be considered by both clinical doctors and people. There is still no consensus on the impact of smoking and alcohol use on bone mineral density in our study.

Immunomodulation by heavy metals as a contributing factor to inflammatory diseases and autoimmune reactions: Cadmium as an example

Cadmium (Cd) represents a unique hazard because of the long biological half-life in humans (20-30 years). This metal accumulates in organs causing a continuum of responses, with organ disease/failure as extreme outcome. Some of the cellular and molecular alterations in target tissues can be related to immune-modulating potential of Cd. This metal may cause adverse responses in which components of the immune system function as both mediators and effectors of Cd tissue toxicity, which, in combination with Cd-induced alterations in homeostatic reparative activities may contribute to tissue dysfunction. In this work, current knowledge concerning inflammatory/autoimmune disease manifestations found to be related with cadmium exposure are summarized. Along with epidemiological evidence, animal and in vitro data are presented, with focus on cellular and molecular immune mechanisms potentially relevant for the disease susceptibility, disease promotion, or facilitating development of pre-existing pathologies.

The endocrine disruptor cadmium: a new player in the pathophysiology of metabolic diseases

Cadmium (Cd), a highly toxic heavy metal, is found in soil, environment and contaminated water and food. Moreover, Cd is used in various industrial activities, such as electroplating, batteries production, fertilizers, while an important non-occupational source is represented by cigarette smoking, as Cd deposits in tobacco leaves. Since many years it is clear a strong correlation between Cd body accumulation and incidence of many diseases. Indeed, acute exposure to Cd can cause inflammation and affect many organs such as kidneys and liver. Furthermore, the attention has focused on its activity as environmental pollutant and endocrine disruptor able to interfere with metabolic and energy balance of living beings. Both in vitro and in vivo experiments have demonstrated that the Cd-exposure is related to metabolic diseases such as obesity, diabetes and osteoporosis even if human studies are still controversial. Recent data show that Cd-exposure is associated with atherosclerosis, hypertension and endothelial damage that are responsible for cardiovascular diseases. Due to the large environmental diffusion of Cd, in this review, we summarize the current knowledge concerning the role of Cd in the incidence of metabolic and cardiovascular diseases.

Blood lead and cadmium levels are negatively associated with bone mineral density in young female adults

Background

The organ toxicities of lead and cadmium have been extensively studied; however, studies of their toxic effects on bone remain limited, especially in young adults. The objective of this study was to examine the associations of blood lead levels (BLL) and blood cadmium levels (BCL) with bone mineral density (BMD) among young adults.

Methods

We performed a cross-sectional study using the National Health and Nutrition Examination Survey 2011–2018 database. Because of the skewed distribution, BLL and BCL were Ln-transformed for analysis. Weighted multivariate regressions were performed to evaluate the associations between LnBLL and LnBCL and lumbar BMD. Subgroup analyses were further performed.

Results

A total of 3234 participants aged 20–35 years were included in this study. No significant association between LnBLL and lumbar BMD was found (β = − 5.6, 95%CI: − 13.5–2.3). However, in the subgroup analysis stratified by sex, this association became negative in women (β = − 18.2, 95%CI: − 29.9– − 6.4). Moreover, this negative association was more prominent in female blacks (β = − 35.5, 95%CI: − 63.4– − 7.6). On the other hand, a negative association between LnBCL and lumbar BMD was found (β = − 7.4, 95%CI: − 14.0– − 0.8). In the subgroup analysis stratified by sex, this negative association only existed in women (β = − 18.7, 95%CI: − 28.0– − 9.5). Moreover, this negative association was more prominent in female whites (β = − 31.1, 95%CI: − 46.2– − 16.1).

Conclusions

Our finding showed that both BLL and BCL were independently and negatively associated with lumbar BMD among young females, but not among young males.

Urine Cadmium as a Risk Factor for Osteoporosis and Osteopenia: A Meta-Analysis

Background: As society ages, the incidence of osteoporosis increases. In several studies, cadmium (Cd) is thought to be related to osteoporosis. However, there are conflicting reports about the relationship between Cd and the risk of osteoporosis and osteopenia. Therefore, the purpose of this meta-analysis was to explore the relationship between Cd and osteoporosis and osteopenia.

Methods: Through a review of the literature, articles published in PubMed as of December 2020 were identified and the references of related publications and reviews were reviewed. Ultimately, 17 eligible articles were selected to determine the relationship between blood and urine Cd concentrations for the risk of osteoporosis or osteopenia. In this study, we performed a classification analysis, heterogeneity test, subgroup analysis, and evaluated publication bias.

Results: A total of 17 studies were included, including seven on blood Cd and 10 on urine Cd. By combining the odds ratio (OR) and 95% confidence interval (CI) for the lowest and highest categories, the odds ratio of blood Cd concentration that increased the risk of osteoporosis or osteopenia was OR 1.21 (95% CI: 0.84–1.58) and that of urine Cd concentration that increased the risk of osteoporosis or osteopenia was OR 1.80 (95% CI: 1.42–2.18), and the results of the subgroup analysis were also consistent.

Conclusions: Our research indicates that while urine cadmium (Cd) concentration may be related to increased risk of osteoporosis and osteopenia, blood Cd concentration may not. Therefore, compared to blood Cd concentration, urine Cd concentration may be more reliable as a risk factor for osteoporosis and osteopenia. This result should be interpreted with caution. Currently. research on the relationship between Cd concentration and osteoporosis and osteopenia is limited, thus, further large, high-quality prospective studies are required to elucidate the relationship between Cd concentration and osteoporosis and osteopenia.

Evaluation of La(XT), a novel lanthanide compound, in an OVX rat model of osteoporosis

Purpose

The purpose of this study was to evaluate the efficacy and toxicity of a novel lanthanum compound, La(XT), in an ovariectomized (OVX) rat model of osteoporosis.

Methods

Twenty-four ovariectomized female Sprague Dawley rats were divided into 3 groups receiving a research diet with/without treatment compounds (alendronate: 3 mg/kg; La(XT) 100 mg/kg) for three months. At the time of sacrifice, the kidney, liver, brain, lung and spleen were collected for histological examination. The trabecular bone structure of the tibiae was evaluated using micro-CT and a three-point metaphyseal mechanical test was used to evaluate bone failure load and stiffness.

Results

No significant differences were noted in plasma levels of calcium, phosphorus, creatinine, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) between the La(XT) treatment compared to the non-treated OVX group. Alendronate-treated animals (positive control) showed higher BV/TV, Tb.N and lower Tb.Th and Tb.Sp when compared to the non-treated OVX group. Mechanical analysis indicated that stiffness was higher in the alendronate (32.88%, p = 0.04) when compared to the non-treated OVX group. Failure load did not differ among the groups.

Conclusions

No kidney or liver toxicities of La(XT) treatments were found during the three-month study. The absence of liver and kidney toxicity with drug treatment for 3 months, as well as the increased trabecular bone stiffness are encouraging for the pursuit of further studies with La(XT) for a longer duration of time.

Long-Term Accumulation of Metals in the Skeleton as Related to Osteoporotic Derangements

The concentrations of metals in the environment are still not within the recommended limits as set by the regulatory authorities in various countries because of human activities. They can enter the food chain and bioaccumulate in soft and hard tissues/organs, often with a long half-life of the metal in the body. Metal exposure has a negative impact on bone health and may result in osteoporosis and increased fracture risk depending on concentration and duration of metal exposure and metal species. Bones are a long-term repository for lead and some other metals, and may approximately contain 90% of the total body burden in birds and mammals. The present review focuses on the most common metals found in contaminated areas (mercury, cadmium, lead, nickel, chromium, iron, and aluminum) and their effects on bone tissue, considering the possibility of the long-term bone accumulation, and also some differences that might exist between different age groups in the whole population.

Cadmium exposure negatively affects the microarchitecture of trabecular bone and decreases the density of a subset of sympathetic nerve fibers innervating the developing rat femur

Cadmium (Cd) is toxic to the skeletal system resulting in bone loss and pain. We aimed at determining the effect of chronic Cd exposure on bone density and microarchitecture along with changes in the density of a subset of sensory and sympathetic nerve fibers innervating the developing rat femur. Newborn male Wistar rats were injected daily for 49 days with CdCl₂ (1 mg/kg i.p.) or saline solution (control group). At the day of sacrifice, levels of Cd in the right femur, liver and kidney were determined by atomic absorption spectrophotometry. Additionally, microCT followed by immunohistochemical analyses were performed in the left femur. Results showed Cd accumulation in trabecular bone neared levels seen in liver and kidney. Cd concentration in cortical bone was significantly lower versus trabecular bone. MicroCT analysis revealed that Cd-exposed rats had a significant decrease in trabecular bone parameters at the distal femoral metaphysis; however, most of the cortical bone parameters were not significantly affected. Cd-exposed rats showed a significant loss of TH⁺ sympathetic nerve fibers, but not of CGRP⁺ sensory nerve fibers, at the level of bone marrow of the femoral diaphysis as compared to control rats. This study shows that Cd negatively affects bone density and microarchitecture of trabecular bone and decreases the density of sympathetic nerve fibers innervating rat femur. Future studies are warranted to determine the toxigenic mechanisms of Cd on sympathetic nerves and how sympathetic denervation influences bone loss in animals exposed to Cd.

Statistical optimization of textile dye effluent adsorption by Gracilaria edulis using Plackett-Burman design and response surface methodology

Statistical optimization models were employed to optimize the adsorption of textile dye effluent onto Gracilaria edulis. Significant factors responsible for adsorption were determined using Plackett-Burman design (PBD) and were time, pH, and dye concentration. Box-Behnken (BB) design was used for further optimization. The predicted and the experimental values were found to be in good agreement, the coefficient of determination value 0.9935 and adjusted coefficient of determination value 0.9818 indicated that the model was significant. The results of predicted response optimization showed that maximum decolorization could be attained with time 131.51 min, pH 7.48, and dye concentration 23.13%. The model was validated experimentally with 92.65% decolorization efficiency. The experiment was confirmed using Fourier transform infrared spectroscopy (FTIR), high-resolution scanning electron microscope coupled with energy dispersive X-ray analysis (HR-SEM-EDX), X-ray diffraction spectrometry (XRD) and Brunauer-Emmett-Teller (BET) surface area and pore size analysis techniques. Desorption studies at various pH (2–14) were performed and a maximum of 23% of the dye was recovered from the adsorbed biomass.

TGF-β-activated kinase 1 (TAK1) mediates cadmium-induced autophagy in osteoblasts via the AMPK / mTORC1 / ULK1 pathway

Cadmium (Cd) is one of worldwide environmental pollutants that causes bone homeostasis, which depends on the resorption of bones by osteoclasts and formation of bones by the osteoblasts (OB). However, the Cd toxicity on OB and its mechanism are unclear. Autophagy is an evolutionarily conserved degradation process in which domestic intracellular components are selectively digested for the recycling of nutrients and energy. This process is indispensable for cell homeostasis maintenance and stress responses. Dysregulation at the level of autophagic activity consequently disturbs the balance between bone formation and bone resorption and mediates the onset and progression of multiple bone diseases, including osteoporosis. TAK1 has been recently emerged as an activator of AMPK and hence an autophagy inducer. AMPK is a key molecule that induces autophagy and regulates cellular metabolism to maintain energy homeostasis. Conversely, autophagy is inhibited by mTORC1. In this study, we found that Cd treatment caused the formation of autophagosomes, LC3-II lipidation and p62 downregulation, and the increased autophagic flux, indicating that Cd treatment induced autophagy in OBs. Cd treatment induced TAK1 activation mediated AMPK phosphorylation, which promoted autophagy via phosphorylation of ULK1 at S317. Meanwhile, Cd treatment dramatically decreased mTORC1, S6K1, 4E-BP1, S6, ULK1^S555 and ULK1^S757 phosphorylation, suggesting that mTORC1 activity was inhibited and inactive mTORC1 prevents ULK1 activation by phosphorylating ULK1 at SerS555 and Ser757. Our data strongly suggest that TAK1 mediates AMPK activation, which activates ULK1 by phosphorylating ULK1^S317 and suppressing mTORC1-mediated ULK1^S555 and ULK1^S757 phosphorylation. Our study has revealed a signaling mechanism for TAK1 in Cd-induced autophagy in OBs.

Nigerian foods of probiotics relevance and chronic metal exposure: a systematic review

Probiotics are functional foods with a wide armamentarium of health benefits in man including metal chelation. Given the unacceptable blood lead levels and the near ignorance or negligence of heavy metals in both diagnoses and management of diseases in Nigeria, it is feared that these metals are involved in the aetiogenesis of several ailments from preeclampsia, metabolic syndrome, cancer, etc. This is an insight on Nigerian fermented foods and their possible role as metal chelators in the management of the chronic heavy metal exposure in Nigeria. One hundred and five articles fulfilled the inclusion criteria. Google scholar, PubMed and SCOPUS were searched for articles reporting fermented foods and probiotics in Nigeria. Only studies published in English Language were included, but there was no limitation in year of study. One hundred and five articles fulfilled the inclusion criteria. Studies from some African countries suggest that fermented foods of probiotics relevance have effectively shown metal chelation properties. Consumption of Nigerian fermented foods may hold a promise in checking the high body burden of heavy metals in Nigeria. Graphic abstract.

Molecular and cellular mechanisms linking air pollution and bone damage

Air pollution is the second most important risk factor associated with noncommunicable diseases after smoking. The effects of pollution on health are commonly attributable to particulate matter (PM), a complex mixture of particles suspended in the air. PM can penetrate the lower respiratory tract and has harmful direct and indirect effects on different organs and tissues. Direct effects are caused by the ability of PM components to cross the respiratory membrane and enter the bloodstream; indirect effects are systemic consequences of the local airway response. Recent work suggests that PM is an independent risk factor for low bone mineral density and osteoporosis-related fractures. Osteoporosis is a common age-related disease closely linked to bone fractures, with severe clinical consequences affecting quality of life, morbidity, and mortality. In this review, we discuss potential mechanisms behind the association between outdoor air pollution, especially PM, and bone damage. The discussion features four main mechanisms: 1) several different atmospheric pollutants can induce low-grade systemic inflammation, which affects bone metabolism through a specific effect of cytokines such as TNFα, IL-1β, IL-6, and IL-17 on osteoblast and osteoclast differentiation and function; 2) some pollutants, particularly certain gas and metal compounds, can cause oxidative damage in the airway and bone cells; 3) different groups of pollutants can act as endocrine disruptors when binding to the receptors in bone cells, changing their functioning; and 4) air pollution can directly and indirectly cause vitamin D deficiency. Characterizing these mechanisms will better define the physiopathology of bone damage, and recognizing air pollution as a modifiable risk factor for osteoporosis will inform environmental policies. Such knowledge will also guide the prevention of fractures due to fragility and help reduce health-related costs.

Biomarkers of exposure and early effect in three contaminated sites of southern Italy: protocols for etiological epidemiological studies

INTRODUCTION

Environmental pollution has been progressively becoming one of the main risk factors to human diseases. In particular, populations living in high-contaminated sites are particularly exposed to environmental toxicants, with consequent increased risks to human health. In Italy, there are currently ongoing three epidemiological etiological studies aimed at evaluating the association between exposure to inorganic and organic chemicals and presence of biological markers of early effects in population living in three National Priority Contaminated Sites (NPCSs). Specifically, the correlations concern preclinical indicators of liver disease in Priolo NPCS, thyroid diseases in Milazzo-Valle del Mela NPCS and cardiovascular risk and kidney damage in Crotone NPCS.

METHODS AND ANALYSIS

Overall, approximately 1300 subjects of both sexes will be enrolled in the three NPCSs according to specific inclusion criteria. For each subject, serum and urine specimens are collected, on which the determination of biological markers of exposure and early effects for the selected outcomes are performed. Individual information on environmental and occupational exposure, medical history, diet and life habits is obtained through questionnaires provided by web platform. In Milazzo-Valle del Mela and Crotone NPCSs, not invasive instrumental and imaging examinations are performed in order to evaluate further risk factors of thyroid carcinoma and cardiovascular disease, respectively.

ETHICS AND DISSEMINATION

The protocol studies have been approved by the Ethics Committees responsible for the three involved NPCSs: the Ethics Committee 'Catania 2' for the NPCS of Priolo (21 July 2017, n. 500/2017/CECT2), the Ethics Committee of the University Hospitals of Messina for the NPCS of Milazzo-Valle del Mela (19 February 2018, n.2/2018); the Ethics Committee of the Region of Calabria for the NPCS of Crotone (20 July 2017, n. 174). Results will be disseminated among policy-makers, citizens, stakeholders and scientific community through the organisation of conferences and events, and the publication on international peer/reviewed journals.

Hormesis Effects of Nano- and Micro-sized Copper Oxide

The concerns about the possible risk of manufactured nanoparticles (NPs) have been raised recently. Nano- and micro-sized copper oxide (CO and CONP) are widely used in many industries. In this regard, in-vitro studies have demonstrated that CONP is a toxic compound in different cell lines. Despite their unique properties, NPs possess unexpected toxicity profiling relative to the bulk materials. This study was designed to examine and compare the toxic effects of CO and CONPs in-vivo and in isolated rat mitochondria. Male Wistar albino rats received 50 to 1000 mg/kg CO or CONP by gavage and several toxicological endpoints including biochemical indices and oxidative stress markers. Then, the pathological parameters in the multiple organs such as liver, brain, spleen, kidney, and intestine were assessed. Mitochondria were isolated from the rat liver and several mitochondrial indices were measured. The results of this study demonstrated that CO and CONP exhibited biphasic dose-response effects. CONPs showed higher toxicity compared with the bulk material. There were no significant changes in the results of CONP and CO in isolated rat liver mitochondria. The present studies provided more information regarding the hormetic effects of CO and CONPs in-vivo and in isolated rat mitochondria.

The associations among lead exposure, bone mineral density, and FRAX score: NHANES, 2013 to 2014

Lead exposure has been suspected as a risk factor for osteoporosis. However, in epidemiological studies, the association between environmental lead exposure and bone health were inconsistent. With the decrease of lead exposure in recent decades, we evaluated the association between lead exposure and bone mineral density (BMD) in the general US population in this study. We analyzed data on 1859 adults (aged ≥40 years) from the National Health and Nutrition Examination Survey (NHANES) conducted in 2013-2014 to determine the relationship among lead exposure measured by both blood and urine lead concentration, BMD of total spine and femur, and FRAX score in a cross-sectional study. In premenopausal women, the results showed a 1-unit increase in natural log-transformed blood and urine lead levels was associated with a decrease in total femur BMD of 0.061 g/cm² (S.E. = 0.015; p = 0.001) and 0.046 g/cm² (S.E. = 0.018; p = 0.020), respectively. Moreover, in premenopausal women, a 1-unit increase in natural log-transformed blood level was associated with a decrease in total spine BMD of 0.054 g/cm² (S.E. = 0.019; p = 0.013). Both FRAX scores were positively correlated with blood and urine lead levels in subjects without fractures, while the 10-year hip fracture risk score was positively associated with lead exposure in subjects with a history of fracture or vertebral fracture. In conclusion, lead exposure was associated with decreased total femur and spine BMD, and FRAX score in the general US population. Further research is needed to elucidate the causal relationship among lead exposure, BMD, and fracture risk.

Osteocyte viability and bone density in cadmium chloride-induced osteoporosis ameliorated with Pilostigma thonningii stem bark-extracted D-3-O-methy-chiroinositol

BACKGROUND

This study examined the ameliorative effect of D-3-O-methyl-chiroinositol, isolated from the stem bark of Piliostigma thonningii, on cadmium chloride-induced osteoporosis in male Wistar rats.

METHODS

Thirty-six rats were assigned to three treatment groups (n = 12). Group A (2 mL distilled water), group B: (2.5 mg/kg b.w. CdCl2) and group C: (2.5 mg/kg b.w. CdCl2 and D-3-O-methyl-chiroinositol 2 mg/kg b.w.). Bone ash, calcium, phosphate, magnesium, and zinc content, as well as bone histological changes were determined at the end of months 1, 2, and 3.

RESULTS

There were significant differences (P ≤ 0.05) in the weight of the cervical, tibia, and femoral bones in all groups. The serum concentration of CdCl2 was significantly different across the three groups with time. There was significant variation (P < 0.005) in the mean bone ash across groups. The concentration of OH-proline was significantly different (P < 0.0001) across groups. There were significant differences (P < 0.0001) in bone calcium, magnesium, zinc, and phosphorus concentrations. Histology revealed high levels of bone mineralisation in the CdCl2-treated group, indicative of osteoporosis with hypertrophied osteocytes, while the femur of Wistar rats treated with D-3-O-methyl-chiroinositol showed bone trabeculae and viable osteocytes.

CONCLUSION

The study concluded that D-3-O-methyl-chiroinositol extract from Piliostigma thionningii stem bark ameliorated cadmium chloride-induced osteoporosis in male Wistar rats.

Anti-Osteogenic Activity of Cadmium in Zebrafish

Among the many anthropogenic chemicals that end up in the aquatic ecosystem, heavy metals, in particular cadmium, are hazardous compounds that have been shown to affect developmental, reproductive, hepatic, hematological, and immunological functions in teleost fish. There is also evidence that cadmium disturbs bone formation and skeletal development, but data is scarce. In this work, zebrafish was used to further characterize the anti-osteogenic/osteotoxic effects of cadmium and gain insights into underlying mechanisms. Upon exposure to cadmium, a reduction of the opercular bone growth was observed in 6-days post-fertilization (dpf) larvae and an increase in the incidence of skeletal deformities was evidenced in 20-dpf post-larvae. The extent and stiffness of newly formed bone was also affected in adult zebrafish exposed to cadmium while regenerating their caudal fin. A pathway reporter assay revealed a possible role of the MTF-1 and cAMP/PKA signaling pathways in mechanisms of cadmium osteotoxicity, while the expression of genes involved in osteoblast differentiation and matrix production was strongly reduced in cadmium-exposed post-larvae. This work not only confirmed cadmium anti-osteogenic activity and identified targeted pathways and genes, but it also suggested that cadmium may affect biomechanical properties of bone.

Suppressing inflammation and enhancing osteogenesis using novel CS-EC@Ca microcapsules

The aim of this study was to investigate the suppression of inflammation and enhancement of osteogenesis using chitosan-coated calcium hydroxide-loaded microcapsules (CS-EC@Ca microcapsules) in vivo. Circular defects were created in the mandibular bones of rabbits and filled with Ca(OH)₂ , Bio-oss, or CS-EC@Ca microcapsules, and rabbits without drug implantation served as the controls. Lipopolysaccharides were injected in situ daily in all groups for 7 days. Mandibular bones were investigated at 4 and 12 weeks after surgery using micro-CT, histological observations, and real-time PCR analysis. At the postoperation, there was more substantial nascent bone in the microcapsule and Bio-oss groups than in the control group. The recovery of the rabbits in the Ca(OH)₂ group was slower than the control group, as determined using micro-CT and histological staining. Osteocalcin and collagen type I production was not significantly different between the microcapsule and Bio-oss groups (p > 0.05), but the expression levels of the two molecules were significantly increased compared to the control and Ca(OH)₂ groups at postoperation (p < 0.05). The mRNA transcript levels of inflammatory factors in the microcapsule group had the most reduced expression of IL-6 and TNF-α (p < 0.05). The microcapsules significantly reduced inflammation and promoted osteogenesis in this rabbit model of inflammatory bone destruction. Our findings indicate that CS-EC@Ca microcapsules hold potential for use in apical periodontitis treatment. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 3222-3230, 2018.

Study on the relationship between age and the concentrations of heavy metal elements in human bone

Background

Excessive amounts of heavy metals such as cadmium, chromium, cobalt, lead, thallium, and manganese are extremely harmful to the human body. These elements can accumulate in bone and impact bone metabolism. In this study, we investigated the relationship between age and the concentrations of these elements in human bone and blood.

Methods

Bone and blood samples were obtained from both older and younger patients. The concentrations of the elements under investigation were measured by inductively coupled plasma mass spectrometry (ICP-MS), and the specific concentrations in the bone and blood were then calculated.

Results

The results showed that with increasing age, the concentrations of chromium, cobalt, and thallium in bone decreased significantly, while the concentration of cadmium in bone markedly increased. However, there was no clear correlation between age and the concentrations of these heavy metals in blood. Notably, there was a close correlation between the concentration of cobalt in bone and the presence of osteopenia.

Conclusions

Senescence of the human body is accompanied by the shifting of cobalt, chromium, and thallium from the bone to the outer- bone. However, the concentration of cadmium in bone increases with age. These changes are very likely to be related to the equilibrium of bone metabolism in senescent individuals. In addition, only cobalt was shown to be significantly related to osteopenia.