Chronic fluorosis: The disease and its anaesthetic implications

An overview of magnesium-based implants in orthopaedics and a prospect of its application in spine fusion

Due to matching biomechanical properties and significant biological activity, Mg-based implants present great potential in orthopedic applications. In recent years, the biocompatibility and therapeutic effect of magnesium-based implants have been widely investigated in trauma repair. In contrast, the R&D work of Mg-based implants in spinal fusion is still limited. This review firstly introduced the general background for Mg-based implants. Secondly, the mechanical properties and degradation behaviors of Mg and its traditional and novel alloys were reviewed. Then, different surface modification techniques of Mg-based implants were described. Thirdly, this review comprehensively summarized the biological pathways of Mg degradation to promote bone formation in neuro-musculoskeletal circuit, angiogenesis with H-type vessel formation, osteogenesis with osteoblasts activation and chondrocyte ossification as an integrated system. Fourthly, this review followed the translation process of Mg-based implants via updating the preclinical studies in fracture fixation, sports trauma repair and reconstruction, and bone distraction for large bone defect. Furthermore, the pilot clinical studies were involved to demonstrate the reliable clinical safety and satisfactory bioactive effects of Mg-based implants in bone formation. Finally, this review introduced the background of spine fusion surgeryand the challenges of biological matching cage development. At last, this review prospected the translation potential of a hybrid Mg-PEEK spine fusion cage design.

Proteomics Sequencing Reveals the Role of TGF-β Signaling Pathway in the Peripheral Blood of Offspring Rats Exposed to Fluoride

The underlying mechanism of fluorosis has not been fully elucidated. The purpose of this study was to explore the mechanism of fluorosis induced by sodium fluoride (NaF) using proteomics. Six offspring rats exposed to fluoride without dental fluorosis were defined as group A, 8 offspring rats without fluoride exposure were defined as control group B, and 6 offspring rats exposed to fluoride with dental fluorosis were defined as group C. Total proteins from the peripheral blood were extracted and then separated using liquid chromatography-tandem mass spectrometry. The identified criteria for differentially expressed proteins were fold change > 1.2 or < 0.83 and P < 0.05. Gene Ontology function annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed using the oeCloud tool. The 177 upregulated and 22 downregulated proteins were identified in the A + C vs. B group. KEGG pathway enrichment analysis revealed that transforming growth factor-β (TGF-β) signaling pathway significantly enriched. PPI network constructed using Cytoscape confirmed RhoA may play a crucial role. The KEGG results of genes associated with fluoride and genes associated with both fluoride and inflammation in the GeneCards database also showed that TGF-β signaling pathway was significantly enriched. The immunofluorescence in HPA database showed that the main expression sites of RhoA are plasma membrane and cytosol, while the main expression site of Fbn1 is the Golgi apparatus. In conclusion, long-term NaF intake may cause inflammatory response in the peripheral blood of rats by upregulating TGF-β signaling pathway, in which RhoA may play a key role.

Development of magnetic La doped Al2O3 core-shell nanoparticle loaded hydrogel for selective recovery of fluoride from aquatic medium

The selective removal of pollutants from water bodies is regarded as a conciliation between the rapid expansion of industrial activities and need of clean water for sustainability. Fluoride is one such geogenic pollutant, and various materials have already been reported. Developing an efficient field employable material is however a challenge. Herein, we report the synthesis and competencies of strategically designed magnetic La-doped Al2O3 core-shell nanoparticle loaded polymeric nanohybrid as a benchmark fluoride sorbent. A facile synthesis strategy involved fabrication of Fe3O4 magnetic core followed by growth of La doped Al2O3 shell using sol-gel method. Doping of La2O3 into Al2O3 structure was optimised (6%), resulting in Fe3O4-Al0.94 La0.06O1.5 core-shell particles which provided exceptional fluoride affinity. The obtained magnetic Fe3O4-Al0.94La0.06O1.5 core-shell nanoparticles were then loaded (22%) into alginate to form cross-linked hydrogel beads (Fe3O4-Al0.94 La0.06 O1.5-Ca-ALG). These prepared hydrogel beads were characterised and utilized for selective recovery of fluoride under different ambient conditions. Driving forces for enhanced fluoride uptake by La doped Al2O3 were investigated and explained with the help of both experimental observation and theoretical simulation. Density functional theory calculations indicated significant expansion in the cell volume of Al2O3 due to La doping which favoured the fluoride sorption. The calculated defect formation energy for the incorporation of F into Al2O3 was found to decrease in the presence of La. XPS analysis suggested direct interaction of fluoride with Al, forming Al-F bond and breaking Al-O bond. Different vital parameters for uptake were optimised. Also, kinetics, isotherm and diffusion models were evaluated. Developed hydrogel beads attained record sorption capacity of 132.3 mgg-1 for fluoride. Overall, excellent stability, no leaching of constituents, effectiveness for selective fluoride recovery from groundwater, brand it a perfect epitome of sustainable water treatment application.

The fluorosis conundrum: bridging the gap between science and public health

Fluorosis, a chronic condition brought on by excessive fluoride ingestion which, has drawn much scientific attention and public health concern. It is a complex and multifaceted issue that affects millions of people worldwide. Despite decades of scientific research elucidating the causes, mechanisms, and prevention strategies for fluorosis, there remains a significant gap between scientific understanding and public health implementation. While the scientific community has made significant strides in understanding the etiology and prevention of fluorosis, effectively translating this knowledge into public health policies and practices remains challenging. This review explores the gap between scientific research on fluorosis and its practical implementation in public health initiatives. It suggests developing evidence-based guidelines for fluoride exposure and recommends comprehensive educational campaigns targeting the public and healthcare providers. Furthermore, it emphasizes the need for further research to fill the existing knowledge gaps and promote evidence-based decision-making. By fostering collaboration, communication, and evidence-based practices, policymakers, healthcare professionals, and the public can work together to implement preventive measures and mitigate the burden of fluorosis on affected communities. This review highlighted several vital strategies to bridge the gap between science and public health in the context of fluorosis. It emphasizes the importance of translating scientific evidence into actionable guidelines, raising public awareness about fluoride consumption, and promoting preventive measures at individual and community levels.

Microstructural Analysis of Cancellous Bone in Fluorosis Rats

Skeletal fluorosis likely alters bone structural properties on the cortical and cancellous tissue levels in view that fluorine ion replaces bone mineral composition. Our previous study showed high bone turnover occurred in cortical bone of skeletal fluorosis. Therefore, this study further analyzed the microstructure of cancellous bone in fluorosis rats. Rats were randomly assigned into three groups: the control, low-dose fluoride group (10 mgF-/kg·day), and high-dose fluoride group (20 mgF-/kg·day). Rats were orally administered with fluoride for 1, 2, and 3 months of periods. The trabecular bone parameters of tibia were detected with micro CT and analyzed with software. The activities of glutathione peroxidase (GPX), superoxide dismutase (SOD), and the content of malondialdehyde (MDA) in serum were measured. Results showed that severity of dental fluorosis rose with the increase of dose and prolongation of fluoride exposure. Meantime, the poorer connectivity and less trabecular bone network were observed in cancellous bone of rats treated with fluoride. Data analysis indicated that fluoride treatment significantly decreased bone volume and connectivity degree, but amplified trabecular space in 1 and 2 months of periods. Intriguingly, trabecular thickness significantly decreased in 1-month high-dose fluoride group, but returned to the control in 3 months of period. Fluoride treatment mainly inhibited the GPX activity and increased the MDA level to activate oxidative stress. This study confirmed that excessive fluoride impaired cancellous bone and caused redox imbalance.

Clinical and Forensic Signs Resulting from Exposure to Heavy Metals and Other Chemical Elements of the Periodic Table

Several heavy metals and other chemical elements are natural components of the Earth’s crust and their properties and toxicity have been recognized for thousands of years. Moreover, their use in industries presents a major source of environmental and occupational pollution. Therefore, this ubiquity in daily life may result in several potential exposures coming from natural sources (e.g., through food and water contamination), industrial processes, and commercial products, among others. The toxicity of most chemical elements of the periodic table accrues from their highly reactive nature, resulting in the formation of complexes with intracellular compounds that impair cellular pathways, leading to dysfunction, necrosis, and apoptosis. Nervous, gastrointestinal, hematopoietic, renal, and dermatological systems are the main targets. This manuscript aims to collect the clinical and forensic signs related to poisoning from heavy metals, such as thallium, lead, copper, mercury, iron, cadmium, and bismuth, as well as other chemical elements such as arsenic, selenium, and fluorine. Furthermore, their main sources of occupational and environmental exposure are highlighted in this review. The importance of rapid recognition is related to the fact that, through a high degree of suspicion, the clinician could rapidly initiate treatment even before the toxicological results are available, which can make a huge difference in these patients’ outcomes.

A Systematic Review and Meta-Analysis of the Relationship Between the Severity of Dental Fluorosis and Fluoride Biomarkers in Endemic Areas

The intake of high concentrations of fluoride, mainly through drinking water, diet and fluoridated dentifrices, produces fluorosis, which in its early stages is manifested as dental fluorosis (DF). To recognize exposure to fluoride in endemic areas and to evaluate the risk of developing health impairment, the WHO has established several biomarkers that are used to determine systemic fluorine (F^-) exposure. Thus, the aim of this study was to conduct a systematic review and meta-analysis of the relationship between the severity of DF and fluoride biomarkers in endemic areas. The protocol of this study was previously registered as CRD42021244974. A digital search was carried out in PubMed/Medline, SpringerLink, Scopus, Cochrane and Google Scholar by employing the keywords "urine", "nails", "hair", "plasma", "saliva" and "dental fluorosis" for the original studies with content associated with F^- for the biomarkers and DF. The mean difference was established as the effect measure for the meta-analysis. Seven studies fulfilled the eligibility criteria, among which five assessed urine and two employed nails as fluoride biomarkers. A positive significant difference was found between the biomarkers and the severity of DF (0.27, p < 0.001) and individually for each biomarker (urine: 0.14, p = 0.001; nails: 0.88, p < 0.05). The F^- concentration in urine and nails is correlated with the severity of DF, with the most evident differences between healthy individuals and those with mild severity. Both biomarkers are adequate to assess this relationship in endemic areas of fluoride and DF.

As and [Formula: see text] cooccurrence in drinking water: critical review of the international scenario, physicochemical behavior, removal technologies, health effects, and future trends

Drinking water contaminated with As and [Formula: see text] is increasingly prevalent worldwide. Their coexistence can have negative effects due to antagonistic or synergistic mechanisms, ranging from cosmetic problems, such as skin lesions and teeth staining, to more severe abnormalities, such as cancer and neurotoxicity. Available technologies for concurrent removal include electrocoagulation ~ adsorption > membranes > chemical coagulation > , and among others, all of which have limitations despite their advantages. Nevertheless, the existence of competing ions such as silicon > phosphate > calcium ~ magnesium > sulfate > and nitrate affects the elimination efficiency. Mexico is one of the countries that is affected by As and [Formula: see text] contamination. Because only 10 of the 32 states have adequate removal technologies, more than 65% of the country is impacted by co-presence problems. Numerous reviews have been published concerning the elimination of As or [Formula: see text]. However, only a few studies have focused on the simultaneous removal. This critical review analyzes the new sources of contamination, simultaneous physicochemical behaviors, available technologies for the elimination of both species, and future trends. This highlights the need to implement technologies that work with actual contaminated water instead of aqueous solutions (55% of the works reviewed correspond to aqueous solutions). Similarly, it is necessary to migrate to the creation of pilot, pre-pilot, or prototype scale projects, because 77% of the existing studies correspond to lab-scale research.

Study of Chitosan Ingestion Remitting the Bone Damage on Fluorosis Mice with Micro-CT

Chronic excessive fluoride exposure may lead to fluorosis, which causes health problems like a decrease in bone mechanical strength. It was speculated that chitosan may combine with fluorine to form in vivo organic fluorine, and may reduce the damage caused by fluorine. Hence, it is necessary to conduct a study to investigate the influence of chitosan on fluorosis mice. To investigate this problem, forty-four 4-week-old male Kunming mice were randomly divided into four groups, the control group, the fluoride group, the fluoride plus chitosan group, and the chitosan group. After 100 days of feeding, the femurs were collected to scan the Micro-CT image. The ultimate load of the femur in the fluoride group was significantly lower than control group. The trabecular separation was increased in the fluoride group compared with the fluoride plus chitosan group and the chitosan group. The level of trabecular thickness was increased in the fluoride plus chitosan group compared with the fluoride group. Our findings suggest that chitosan ingestion can improve the condition of cancellous bone and cortical bone affected by fluorine.

Antioxidant Phytochemicals for the Prevention of Fluoride-Induced Oxidative Stress and Apoptosis: a Review

Fluorosis is a major public health problem globally. The non-availability of specific treatment and the irreversible nature of dental and skeletal lesions poses a challenge in the management of fluorosis. Oxidative stress is known to be one of the most important mechanisms of fluoride toxicity. Fluoride promotes the accumulation of reactive oxygen species by inhibiting the activity of antioxidant enzymes, resulting in the excessive production of reactive oxygen species at the cellular level which further leads to activation of cell death processes such as apoptosis. Phytochemicals that act as antioxidants have the potential to protect cells from oxidative stress. Evidence confirms that clinical symptoms of fluorosis can be mitigated to some extent or prevented by long-term intake of antioxidants and plant products. The primary purpose of this review is to examine recent findings that focus on the amelioration of fluoride-induced oxidative stress and apoptosis by natural and synthetic phytochemicals and their molecular mechanisms of action.

Biphasic Functions of Sodium Fluoride (NaF) in Soft and in Hard Periodontal Tissues

Sodium fluoride (NaF) is widely used in clinical dentistry. However, the administration of high or low concentrations of NaF has various functions in different tissues. Understanding the mechanisms of the different effects of NaF will help to optimize its use in clinical applications. Studies of NaF and epithelial cells, osteoblasts, osteoclasts, and periodontal cells have suggested the significant roles of fluoride treatment. In this review, we summarize recent studies on the biphasic functions of NaF that are related to both soft and hard periodontal tissues, multiple diseases, and clinical dentistry.

Skeletal Fluorosis: A Case of Inhalant Abuse Leading to a Diagnosis of Colon Cancer

Skeletal fluorosis is a long-term bone disease that develops when prolonged fluoride toxicity leads to osteosclerosis and bone deformities that result in crippling pain and debility. The disease is endemic to many countries due to environmental or industrial exposures. However, rare cases in the United States have been reported from various causes including heavy toothpaste ingestion, excessive tea consumption, voriconazole use, and inhalant abuse. Here, we present a case of a 41-year-old man who presented for weight loss and severe joint pains due to bony sclerotic lesions found on X-rays. Social history revealed that he had been recreationally inhaling compressed air dusters used for cleaning electronics. Owing to concern for malignancy, he underwent an extensive work-up which led to a diagnosis of colon cancer, but positron emission tomography/computed tomography (PET/CT) and bone biopsy were unexpectedly negative for metastatic bone disease. Further characterization of his lesions by skeletal survey led to a diagnosis of skeletal fluorosis secondary to inhalant abuse. As in this patient, the disease can be difficult for clinicians to recognize as it can be mistaken for various boney diseases such as metastatic cancer. However, once there is clinical suspicion for skeletal fluorosis, various tests to help confirm the diagnosis can include serum and urine fluoride levels, skeletal survey, and bone ash fluoride concentration. Treatment of skeletal fluorosis primarily involves cessation of fluoride exposure, and recovery can take years. Ultimately, further study is required to develop recommendations and guidelines for diagnosis, management, and prognosis of the disease in the United States.

Effects of Fluoride on Oxidative Stress Markers of Lipid, Gene, and Protein in Rats

Endemic fluorosis is a systemic chronic disease caused by excessive intake of fluoride. It is widely accepted that oxidative stress is closely related to fluorosis; however, molecular mechanism of oxidative stress in fluorosis remains unclear. This study investigated the effects of fluoride (F) on oxidative stress markers of lipid, gene, and protein in rats for revealing molecular mechanism of oxidative stress in fluorosis. The results showed concentration and exposure time of fluoride both had a significant effect on MDA and 8-OHdG. Fluoride concentration significantly impacted AGEs level, but exposure time did not. AOPP was not statistically different among the groups. AGEs decreased with the increase of fluoride in the rats with 3 months of fluoride treatment. The correlation analysis showed the degree of dental fluorosis was significantly negatively correlated with 8-OHdG at 1 month and 3 months, and negatively correlated with AGEs at 3 months. In the rats with 100 mg/L of fluoride treatment, MDA was significant positively correlated with 8-OHdG, and negatively correlated with AGEs. 8-OHdG was significantly negatively correlated with AGEs in the control group and 100 mg/L fluoride group. Taken together, fluoride had different effects on oxidative stress markers of lipid, gene, and protein. Excessive fluoride could increase MDA content, and decrease 8-OHdG and AGEs. These findings suggest that oxidative stress involved in molecular pathogenesis of fluorosis is complicated, and needs to furtherly study in the future.

Sclerotic bone lesions caused by non-infectious and non-neoplastic diseases: a review of the imaging and clinicopathologic findings

Bone sclerosis is a focal, multifocal, or diffuse increase in the density of the bone matrix on radiographs or computed tomography (CT) imaging. This radiological finding can be caused by a broad spectrum of diseases, such as congenital and developmental disorders, depositional disorders, and metabolic diseases. The differential diagnosis can be effectively narrowed by an astute radiologist in the light of the clinical picture and typical findings on imaging. Some of these lesions are rare and have been described as case reports and series in the literature. This article aims to collate the clinical-radiologic findings of non-infectious and non-neoplastic causes of bone sclerosis with relevant imaging illustrations.

Skeletal Fluorosis With Thoracic Myelopathy: A Report of 2 Cases

BACKGROUND

To report 2 different presentations of thoracic myelopathy with ossification of ligamantum flavum (OLF) due to fluorosis.

METHODS

Two females presented with thoracic myelopathy secondary to spinal stenosis with OLF due to fluorosis. On examination, the first patient had a grade 4 power in both lower limbs with altered sensation below L1 dermatome. She had segmental OLF on magnetic resonance imaging and computed tomography and was treated with posterior thoracic laminectomy and recovered well. The second patient had a history of a prior thoracic laminectomy at another institution and presented with paraplegia with bladder involvement. Radiological investigations revealed a 3-column injury at the level of D8/D9. This patient was treated with decompression and stabilization.

RESULTS

The first patient recovered neurologically and regained independent ambulation while the second patient had a reduction in spasticity but no recovery of power or bladder function.

CONCLUSION

Different presentations and causes of myelopathy due to OLF should be recognized and treated. An unstable injury is very rare and should not be missed.

miR-122-5p Mediates Fluoride-Induced Osteoblast Activation by Targeting CDK4

Chronic intake of fluoride, existing in the environment, may cause endemic fluorosis, which is characterized by the occurrence of skeletal and dental fluorosis. However, the pathogenesis of fluorosis has not yet been elucidated. Abnormal osteoblast proliferation and activation have a pivotal role in bone turnover disorders which are linked to skeletal fluorosis. MicroRNAs are involved in fundamental cellular processes, including cell proliferation. Based on our previous study, population study and in vitro experiments were designed to understand the effect of miR-122-5p on osteoblast activation in skeletal fluorosis through targeting cyclin-dependent kinase 4 (CDK4). In human populations with coal-burning type fluoride exposure, the results showed that miR-122-5p was downregulated but CDK4 expression was upregulated and miR-122-5p was negatively correlated with CDK4 expression. Furthermore, in human osteoblasts treated with sodium fluoride, we demonstrated that miR-122-5p mediated osteoblast activation of skeletal fluorosis via upregulation of the CDK4 protein. In support of this, dual-luciferase reporter assay showed that miR-122-5p modulated CDK4 protein levels by targeting its 3'-untranslated region. These findings show, for the first time, that miR-122-5p may be involved in the cause and development of skeletal fluorosis by targeting CDK4.

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

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

Fluoride in Drinking Water and Skeletal Fluorosis: a Review of the Global Impact

When safe and adequate exposure of an essential trace element is exceeded it becomes potentially toxic. Fluoride is one classic example of such a double edged sword which both plays a fundamental role in the normal growth and development of the body for example the consumption of levels between 0.5-1.0 ppm via drinking water is beneficial for prevention of dental caries but its excessive consumption leads to development of fluorosis. PURPOSE OF REVIEW: The abundance of fluorine in the environment as well as in drinking water sources are the major contributors to fluorosis. It is a serious public health concern as it is a noteworthy medical problem in 24 nations including India yet the threat of fluorosis has not been rooted out. The review focuses on recent findings related to skeletal fluorosis and role of oxidative stress in its development. The fluoride mitigation strategies adopted in recent years are also discussed. RECENT FINDINGS BASED ON CASE STUDIES: Recent findings revealed that consumption of fluoride at concentrations of 1.5 ppm is majorly responsible for skeletal fluorosis. The sampling from rural areas showed that 80% villages are having fluoride concentrations more than the WHO permissible limits and people residing in such areas are affected by the skeletal fluorosis and also in the regions of Africa and Asia endemic fluorosis have been accounted in the majority of the region affecting approximately 100 million people. Various mitigation programmes and strategies have been conducted all over the world using defluoridation. Fluorosis is a slow and progressive malady affecting our body and a serious concern to be taken into consideration and to be dealt with effectively. The fluoride toxicity although reversible, is a slow process and the side effects lack treatment options. The treatment options available are either not approachable or affordable in the rural areas commonly suffering from the fluoride toxicity. No specific treatments are available to date to treat skeletal fluorosis affectively; therefore, prevention is one of most safest and best approach to fight fluorosis. The current review lays emphasis on the skeletal fluorosis and its prevalence in recent years. It also includes the recent findings as well as the current strategies related to combat skeletal fluorosis and provides findings that might be helpful to promote the research in the field of effective treatment for fluorosis as well as development of easy and affordable methods of fluoride removal from water.

Recent Biomarkers for Monitoring the Systemic Fluoride Levels in Exposed Populations: A Systematic Review

Fluorides are compounds that can be found in the minerals of soil with volcanic rocks. Different populations are exposed to high levels of fluorides through drinking water that, due to their chronic intake, cause several types of damage to health. Nails and hair, denominated as recent biomarkers, have been employed for monitoring systemic fluoride from long-term exposure to fluorides. The aim of this study was to perform a systematic review of the use of recent biomarkers for monitoring systemic fluoride levels in exposed populations and verify their validity in the measurement of the fluorine (F^-) concentration within the body. A digital search was performed in the databases PubMed/Medline, Springer Link, Cochrane, and Scopus of original articles that employed recent biomarkers for monitoring systemic F^-. Seventeen articles were included in this analysis; the recorded variables were the F^- amount in each assessed biomarker, source of exposure, and total daily fluoride intake (TDFI). TDFI was associated with F^- in nails and hair, as well as the exposure through drinking water. In conclusion, recent biomarkers are adequate for monitoring the systemic fluoride levels by evaluating the chronic/subchronic exposure through different sources, mainly drinking water, considering nails better than hair for this purpose.

Upregulation of miR-200c-3p induced by NaF promotes endothelial apoptosis by activating Fas pathway

Fluoride has been considered as a risk factor of cardiovascular disease due to its endothelial toxicology. However, the mechanism underlying the endothelial toxicity of fluoride has not been clearly illustrated. MiR-200c-3p was strongly linked with endothelial function and its level is increased in serum of fluorosis patients, but it is unclear the role of miR-200c-3p in the fluoride induced endothelial dysfunction. In this study, we confirmed that fluoride exposure induced the apoptosis of endothelial cells both in established rats model and cultured human umbilical vein endothelial cells (HUVECs). And miR-200c-3p was found to be upregulated in NaF treated HUVECs. Fluoride stimulation increased caspase-dependent apoptosis through miR-200c-3p upregulation, with repressing expression of its target gene Fas-associated phosphatase 1 (Fap-1), which functioned as Fas inhibitor. This resulted in activation of Fas-associated extrinsic apoptosis via interaction with increased Fas, Fadd, Cleaved Caspase-8 and Cleaved Caspase-3. The activation of Fas-associated extrinsic apoptosis was abrogated by miR-200c-3p inhibitor. Furthermore, the antiapoptotic effect of downregulated miR-200c-3p was restored by Fap-1 siRNA. These results suggested a determinant role of the miR-200c-3p/Fap-1 axis in fluoride induced endothelial apoptosis.

Diagnosis and management of pediatric metabolic bone diseases associated with skeletal fragility

PURPOSE OF REVIEW

The goal of this review is to give an overview of diagnosis and up-to-date management of major pediatric metabolic bone diseases that are associated with bone fragility, including nutritional rickets, hypophosphatemic rickets, osteogenesis imperfecta, Ehlers--Danlos syndrome, Marfan's syndrome, hypophosphatasia, osteopetrosis and skeletal fluorosis.

RECENT FINDINGS

During the past decade, a number of advanced treatment options have been introduced and shown to be an effective treatment in many metabolic bone disorders, such as burosumab for hypophosphatemic rickets and asfotase alfa for hypophosphatasia. On the other hand, other disorders, such as nutritional rickets and skeletal fluorosis continue to be underrecognized in many regions of the world. Genetic disorders of collagen-elastin, such as osteogenesis imperfecta, Ehlers--Danlos syndrome and Marfan's syndrome are also associated with skeletal fragility, which can be misdiagnosed as caused by non-accidental trauma/child abuse.

SUMMARY

It is essential to provide early and accurate diagnosis and treatment for pediatric patients with metabolic bone disorders in order to maintain growth and development as well as prevent fractures and metabolic complications.

Effect of excess Fluoride consumption on Urine-Serum Fluorides, Dental state and Thyroid Hormones among children in “Talab Sarai” Punjab Pakistan

190 children aged 7-18 years from an endemic fluorotic village “Talab Sarai (n = 130) and a non-fluorotic, control, village “Ottawa” (n = 60) were selected for comparison. Children were examined for fluoride (F-) concentration in drinking water, urine, and serum as well as Dental fluorosis (DF) and thyroid hormone levels. The mean concentration of water fluoride (WF) in the sample group was 6.23 mg/L, urine fluoride (UF) 3.38 mg/L, and serum fluoride (SF) 0.21 mg/L, while DF was 93.07%. Significant elevations (P = 0.000) in the concentration of all these four variables were observed in sample group children as compared to control. Mean Free Tetra-iodothyronine (FT4), Free Tri-iodothyronine (FT3) and Thyroid Stimulating Hormone (TSH) concentrations in the sample group were 16.64pmol/L, 5.57 pmol /L and 4.41 mlU/L, respectively. No marked difference in FT4 (P = 0.1) was noted, while significant elevations in FT3 and TSH (P = 0.000) were found in the sample relative to the control group. 80% of the children displayed clear thyroid hormonal derangements, with 36.92% having high TSH and 43.07% with FT3 and FT4 disorders. A moderate to strong correlation among WF, UF, SF and DF (r = 0.94, 0.60, 0.60, 0.72) and a very strong correlation between WF and TSH (r = 0.9) were observed. Our results suggest that excess F- level that is four times greater than the “safe limit” is not only increasing fluoride concentration in body fluids but is also affecting thyroid hormones in 4 out of 5 children which could lead to abnormal physical and mental growth in later developmental stages.

Skeletal fluorosis: don't miss the diagnosis!

Skeletal fluorosis is a rare toxic osteopathy characterized by massive bone fixation of fluoride. The disease occurs as an endemic problem in some parts of the world and is the result of prolonged ingestion or rarely by inhalation of high amounts of fluoride. Radiographic presentation is mainly characterized by bone changes with osteocondensation and later ossification of many ligaments and interosseous membranes. Skeletal fluorosis is not clinically obvious and can be confused with other rheumatologic disorders. Its severity lies in the development of skeletal deformities and neurological complications. Management of fluorosis generally focuses on symptom treatment.

A hydrazide organogelator for fluoride sensing with hyperchromicity and gel-to-sol transition

Sensing of fluoride in a solvent is highly required in healthcare and environmental rehabilitation. Among the various sensing methods, optical sensing has attracted significant research interest because it can conveniently recognize fluoride. Herein, a low molecular weight organogelator, N′1,N′6-bis(3-(1-pyrrolyl)propanoyl) hexanedihydrazide (DPH), containing a central butyl chain conjugated to two pyrrole rings through hydrazide groups, was used for optical sensing of fluoride in the forms of both solution and organogel. Association of fluoride with the –NH moiety of the hydrazide group endowed the DPH solution in dimethylformamide with a hyperchromicity under 350 nm. Exploiting the UV absorptivity, the DPH solution was examined as a chemosensor, displaying good selectivity toward fluoride among various anions and moderate sensitivity with a detection limit of 0.49 μM. The practical use of the DPH solution was demonstrated for fluoride sensing in toothpaste. Binding of fluoride also changed the molecular interactions of the DPH organogel, resulting in a phase transition from gel to sol. This gel-to-sol transition enabled the sensing of fluoride by the naked eye.

A low-molecular-weight organogelator containing hydrazide groups, DPH, exhibited considerable selectivity and sensitivity for fluoride. The optical sensing of fluoride was demonstrated with the systematic study on the sensing mechanism.

Fluoride regulates the expression of extracellular matrix HSPG and related signaling pathways FGFR3 and Ihh/PTHrP feedback loop during endochondral ossification

Skeletal fluorosis causes growth plate impairment and growth retardation during bone development. Longitudinal bone development is accomplished by endochondral ossification in growth plate. However, the mechanism of fluoride impairs growth plate is unclear. To explore the effect of fluoride on various glycosaminoglycans (GAGs) and related signaling pathways in growth plate during endochondral ossification, SD rats and ATDC5 cells were treated with fluoride and carried out a series of experiments. We found that the expression of heparan sulfate (HS), a kind of GAGs in extracellular matrix, was significantly increased in the growth plate of fluoride-treated rats compared with control rats. Furthermore, the expression of HS synthetic enzyme exostosin 1 (EXT1) and glypican 6 (GPC6), a core protein of HS proteoglycan (HSPG), were significantly increased in fluoride-treated ATDC5 cells compared with control cells (P < 0.05). The expression of related molecules including fibroblast growth factor receptor-3 (FGFR3), signal transducer and activator of transcription 1 (STAT1) and parathyroid hormone-related protein (PTHrP) were significantly increased in the fluoride-treated groups compared with control groups (P < 0.05), and there was significantly decreased in the expression of Indian hedgehog (Ihh) in fluoride-treated groups compared with control groups (P < 0.05). Our data suggested that fluoride increased the content of HSPG in extracellular matrix by promoting the expression of EXT1 and GPC6. Fluoride also activated FGFR3 signaling pathway, inhibited Ihh/PTHrP feedback loop and inhibited endochondral ossification. Nevertheless, the regulation of fluoride on HSPG and related pathways FGFR3 and Ihh/PTHrP feedback loop during endochondral ossification needs to be further studied.

Osseointegration of titanium dental implant under fluoride exposure in rabbits: Micro-CT and histomorphometry study

OBJECTIVE

This study aims to investigate the influence of fluoride exposure on implant osseointegration.

METHODS

A total of 24 male New Zealand white rabbits were randomly divided into the control group and the fluoride exposure group. Rabbits in the control group were fed with tap water, while those in the fluoride exposure group were given 200 mg/L sodium fluoride solution. After 2-month feeding, implants were inserted into the extraction socket immediately after extraction of rabbit mandibular anterior teeth. Four rabbits in each group were sacrificed to collect the implants samples at 1, 2, and 3 months post-implantation, respectively. Radiographic and histomorphometry examinations were performed to evaluate the condition of implant osseointegration.

RESULTS

Bone volume around the implants increased in a time-dependent manner in both groups. Micro-CT images illustrated that the bone mineral density (BMD) in the fluoride exposure group was significantly lower than that in the control group after implantation for 2 and 3 months. The bone-implant contact ratio (BIC) in the fluoride exposure group was much lower than that of the control group at 3 months post-implantation according to histomorphometry examination.

CONCLUSIONS

In rabbit animal model, high fluoride exposure affected the quality of bone surrounding the implant and significantly reduced bone integration of the implant, especially in the late stage of osseointegration.

Matrix metalloproteinase-9 and p53 involved in chronic fluorosis induced blood-brain barrier damage and neurocyte changes

INTRODUCTION

A large number of basic and clinical studies have confirmed that fluoride produces toxic effects on multiple organ systems in the body including the nervous system.

MATERIAL AND METHODS

One hundred twenty Wistar rats were randomly divided into 4 groups with 30 in each group: a high fluoride group (drinking 200 mg/l fluoridated water, 24 weeks); a high fluoride control group (drinking distilled water, 24 weeks); a fluoride removal group (drinking fluoridated water, 12 W; then distilled water, 12 W) and a defluorination control group (drinking distilled water, 24 weeks).

RESULTS

The high fluoride and fluoride removal groups had spinal cord astrocyte edema. The apoptosis rate of spinal nerve cells in the high fluoride group and fluoride removal group were significantly higher (p < 0.01) than in the fluoride control and defluorination control group. The Evans blue (EB) content, matrix metalloproteinase-9 (MMP-9) and p53 expression in the high fluoride group and fluoride removal group were higher (p < 0.01) than in the fluoride control and defluorination control group.

CONCLUSIONS

The apoptosis of spinal cord nerve cells is obviously higher in rats with chronic fluoride exposure. Chronic fluoride exposure leads to high expression of MMP-9, and results in increased damage of the blood-spinal cord barrier. Increased p53 may be one of the factors causing damage. Short-term removal of fluoride has no obvious recovery in apoptosis of spinal cord nerve cells; highly expressed MMP-9 and p53 may be one of the reasons for unrecovered function.

The toxic effect of sodium fluoride on Spodoptera frugiperda 9 cells and differential protein analysis following NaF treatment of cells

Accumulation of excess fluoride has a destructive effect on the environment, endangering human health, affecting organism growth and development, and leading to damage to the biological chain, thereby affecting ecological environment balance. In recent years, numerous studies focused on the molecular mechanisms associated with fluoride toxicity; however, fluoride-toxicity mechanisms in insect cells remain unclear. This study explored the toxic impact of sodium fluoride (NaF) on Spodoptera frugiperda 9 (Sf9) insect cells. High concentrations of NaF (10^-4 M, 10^-3 M and 10^-2 M) resulted in cell enlargement, cell membrane blurring and breakage, and release of cellular contents. Dose-response curves indicated that NaF-specific inhibition rates on Sf9-cell activity increased along with increases in NaF concentration, with a half-inhibitory concentration (IC₅₀) for NaF of 5.919 × 10^-3 M at 72 h. Compared with controls, the percentages of early and late apoptotic and necrotic cells clearly increased based on observed increases in NaF concentrations. Two-dimensional gel electrophoresis combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used to detect differentially expressed proteins in Sf9 cells treated with IC₅₀ NaF, identifying 17 proteins, seven of which were upregulated and 10 downregulated. These results demonstrated that Sf9 cells showed signs of NaF-mediated toxicity through alterations in cell morphology, apoptosis rates, and protein expression.

Curse of Fluorosis

Fluoride was identified to have caries preventive properties and was widely used for fluoridation of water since 1940, especially in developed countries. After this there was sudden increase in the use of fluorides in food items and in oral medicinal products like toothpastes and mouth washes. Inadvertent use of above has lead to increase in fluorosis as a public health problem. In many places high fluorides are naturally present in earth crust leading to high water fluoride content increasing the risk of fluorosis. Maintaining a fine balance of fluorides in the body is mandatory for exploiting its advantages. World Health Organization (WHO) has fixed permissible limit of fluorides in water to 1.5 mg/L as a preventive step to contain fluorosis. Fluorosis has three clinical components: Dental, Skeletal and Non-Skeletal Fluorosis. It occurs with increasing level of fluorides in the body. Acute toxicity due to fluorides is also known and occurs as a result of sudden exposure to high levels of fluorides, usually by ingestion. Once fluorosis occurs it is irreversible without any cure. Only symptomatic and supportive management is possible. Hence prevention is the mainstay of management. Prevention is by using alternative sources of water or its de-fluoridation. National Program for Prevention and Control of Fluorosis (NPPCF) was launched in 2008-9 to identify areas with high fluoride content of water, manage the water bodies, screen schools and community for fluorosis and comprehensive management of cases. Improving quality of drinking water as per standards and improving nutritional status of children are also important components of prevention of fluorosis.

Preliminary Analysis of MicroRNAs Expression Profiling in MC3T3-E1 Cells Exposed to Fluoride

Overexposure to fluoride from environmental sources can cause serious public health problems. Disrupted osteoblast function and impaired bone formation were found to be associated with excessive fluoride exposure. A massive analysis of microRNAs (miRNAs) was used to figure out the possible pathways in which fluoride affects osteoblast function. MC3T3-E1 cells were treated with 8 mg/L of fluorine for 7 days. Total RNA of cells was extracted, and their integrity and purity were tested. RNA samples were analyzed by using miRNA array, including miRNA labeling, hybridization, scanning, and expression data analysis to compare the profiling of miRNA expression between control and fluoride-treated group. Transcriptome analysis console and enrichment analysis calculated by miRSystem were used to predict target genes and collect miRNAs pathway maps. Forty-five upregulated and 31 downregulated miRNAs expression were found in the fluoride-treated group, and most of the verified miRNAs were mature. The KEGG pathway enrichment analysis searched out 36 pathways that scored more than 0.1. These pathways mainly included intracellular signaling, cytokines, metabolism, and cytoskeleton-related pathways. Among them, the Wnt, insulin, TGF-beta, hedgehog, VEGF, and notch pathways in osteoblasts were those mainly affected by fluoride treatment. These results have shown a number of higher level systemic pathways activated by overexposure of fluoride in osteoblastic cells and verified that fluoride affected the molecular crosstalk in the osteoblasts.

iTRAQ-Based Proteomics Analysis of Serum Proteins in Wistar Rats Treated with Sodium Fluoride: Insight into the Potential Mechanism and Candidate Biomarkers of Fluorosis

Fluorosis induced by exposure to high level fluoride is quite widespread in the world. The manifestations of fluorosis include dental mottling, bone damage, and impaired malfunction of soft tissues. However, the molecular mechanism of fluorosis has not been clarified until now. To explore the underlying mechanisms of fluorosis and screen out serum biomarkers, we carried out a quantitative proteomics study to identify differentially expressed serum proteins in Wistar rats treated with sodium fluoride (NaF) by using a proteomics approach of isobaric tagging for relative and absolute quantitation (iTRAQ). We fed Wistar rats drinking water that had 50, 150, and 250 mg/L of dissolved NaF for 24 weeks. For the experimental duration, each rat was given an examination of the lower incisors to check for the condition of dental fluorosis (DF). By the end of the treatment, fluoride ion concentration in serum and lower incisors were detected. The results showed that NaF treatment can induce rat fluorosis. By iTRAQ analysis, a total of 37 differentially expressed serum proteins were identified between NaF-treated and control rats. These proteins were further analyzed by bioinformatics, out of which two proteins were validated by enzyme-linked immunoadsorbent assays (ELISA). The major proteins were involved in complement and coagulation cascade, inflammatory response, complement activation, defense response, and wound response, suggesting that inflammation and immune reactions may play a key role in fluorosis pathogenesis. These proteins may contribute to the understanding of the mechanism of fluoride toxicity, and may serve as potential biomarkers for fluorosis.