Vanadium Compounds as Pro-Inflammatory Agents: Effects on Cyclooxygenases

Effects of exposure to multiple metallic elements in the first trimester of pregnancy on the risk of preterm birth

Exposure to certain heavy metals has been demonstrated to be associated with a higher risk of preterm birth (PTB). However, studies focused on the effects of other metal mixtures were limited. A nested case‒control study enrolling 94 PTB cases and 282 controls was conducted. Metallic elements were detected in maternal plasma collected in the first trimester using inductively coupled plasma‒mass spectrometry. The effect of maternal exposure on the risk of PTB was investigated using logistic regression, least absolute shrinkage and selection operator, restricted cubic spline (RCS), quantile g computation (QGC) and Bayesian kernel machine regression (BKMR). Vanadium (V) and arsenic (As) were positively associated with PTB risk in the logistic model, and V remains positively associated in the multi-exposure logistic model. QGC analysis determined V (69.42%) and nickel (Ni) (70.30%) as the maximum positive and negative contributors to the PTB risk, respectively. BKMR models further demonstrated a positive relationship between the exposure levels of the mixtures and PTB risk, and V was identified as the most important independent variable among the elements. RCS analysis showed an inverted U-shape effect of V and gestational age, and plasma V more than 2.18 μg/L was considered a risk factor for shortened gestation length. Exposure to metallic elements mixtures consisting of V, As, cobalt, Ni, chromium and manganese in the first trimester was associated with an increased risk of PTB, and V was considered the most important factor in the mixtures in promoting the incidence of PTB.

Prosthetic Metals: Release, Metabolism and Toxicity

The development of metallic joint prostheses has been ongoing for more than a century alongside advancements in hip and knee arthroplasty. Among the materials utilized, the Cobalt-Chromium-Molybdenum (Co-Cr-Mo) and Titanium-Aluminum-Vanadium (Ti-Al-V) alloys are predominant in joint prosthesis construction, predominantly due to their commendable biocompatibility, mechanical strength, and corrosion resistance. Nonetheless, over time, the physical wear, electrochemical corrosion, and inflammation induced by these alloys that occur post-implantation can cause the release of various metallic components. The released metals can then flow and metabolize in vivo, subsequently causing potential local or systemic harm. This review first details joint prosthesis development and acknowledges the release of prosthetic metals. Second, we outline the metallic concentration, biodistribution, and elimination pathways of the released prosthetic metals. Lastly, we discuss the possible organ, cellular, critical biomolecules, and significant signaling pathway toxicities and adverse effects that arise from exposure to these metals.

Histological and Memory Alterations in an Innovative Alzheimer's Disease Animal Model by Vanadium Pentoxide Inhalation

Background

Previous work from our group has shown that chronic exposure to Vanadium pentoxide (V2O5) causes cytoskeletal alterations suggesting that V2O5 can interact with cytoskeletal proteins through polymerization and tyrosine phosphatases inhibition, causing Alzheimer's disease (AD)-like hippocampal cell death.

Objective

This work aims to characterize an innovative AD experimental model through chronic V2O5 inhalation, analyzing the spatial memory alterations and the presence of neurofibrillary tangles (NFTs), amyloid-β (Aβ) senile plaques, cerebral amyloid angiopathy, and dendritic spine loss in AD-related brain structures.

Methods

20 male Wistar rats were divided into control (deionized water) and experimental (0.02 M V2O5 1 h, 3/week for 6 months) groups (n = 10). The T-maze test was used to assess spatial memory once a month. After 6 months, histological alterations of the frontal and entorhinal cortices, CA1, subiculum, and amygdala were analyzed by performing Congo red, Bielschowsky, and Golgi impregnation.

Results

Cognitive results in the T-maze showed memory impairment from the third month of V2O5 inhalation. We also noted NFTs, Aβ plaque accumulation in the vascular endothelium and pyramidal neurons, dendritic spine, and neuronal loss in all the analyzed structures, CA1 being the most affected.

Conclusions

This model characterizes neurodegenerative changes specific to AD. Our model is compatible with Braak AD stage IV, which represents a moment where it is feasible to propose therapies that have a positive impact on stopping neuronal damage.

Interaction of Vanadium Complexes with Proteins: Revisiting the Reported Structures in the Protein Data Bank (PDB) since 2015

The structural determination and characterization of molecules, namely proteins and enzymes, is crucial to gaining a better understanding of their role in different chemical and biological processes. The continuous technical developments in the experimental and computational resources of X-ray diffraction (XRD) and, more recently, cryogenic Electron Microscopy (cryo-EM) led to an enormous growth in the number of structures deposited in the Protein Data Bank (PDB). Bioinorganic chemistry arose as a relevant discipline in biology and therapeutics, with a massive number of studies reporting the effects of metal complexes on biological systems, with vanadium complexes being one of the relevant systems addressed. In this review, we focus on the interactions of vanadium compounds (VCs) with proteins. Several types of binding are established between VCs and proteins/enzymes. Considering that the V-species that bind may differ from those initially added, the mentioned structural techniques are pivotal to clarifying the nature and variety of interactions of VCs with proteins and to proposing the mechanisms involved either in enzymatic inhibition or catalysis. As such, we provide an account of the available structural information of VCs bound to proteins obtained by both XRD and/or cryo-EM, mainly exploring the more recent structures, particularly those containing organic-based vanadium complexes.

Regulation of COX-2 expression by selected trace elements and heavy metals: Health implications, and changes in neuronal plasticity. A review

Trace elements or trace metals are essential components of enzymes, proteins, hormones and play a key role in biochemical processes, cell growth and differentiation, as well as in neurotransmission, affecting human physiology. In nature there are also heavy metals that exhibit toxic effects on the human body, including the brain. The importance of trace elements has been established in neurodegenerative disorders, schizophrenia, depression among others. In parallel, an important regulatory element in the above diseases is cyclooxygenase-2 (COX-2), a modulator of the arachidonic acid (AA) pathway, and a cause of neuroinflammation, and glutamate (Glu) dysregulation, affecting calcium (Ca) metabolism in cells. This review presents the effects of major trace elements and heavy metals on COX-2 expression. Calcium (Ca), zinc (Zn), cadmium (Cd), vanadium (V), nickel (Ni), copper (Cu), and iron (Fe) can potentially increase COX-2 expression, inducing neuroinflammation and Glu excitotoxicity; while magnesium (Mg), lithium (Li), and selenium (Se) can potentially decrease COX-2 expression. The associated mechanisms are described in the article.

CNS-Related Effects Caused by Vanadium at Realistic Exposure Levels in Humans: A Comprehensive Overview Supplemented with Selected Animal Studies

Neurodegenerative disorders, which are currently incurable diseases of the nervous system, are a constantly growing social concern. They are progressive and lead to gradual degeneration and/or death of nerve cells, resulting in cognitive deterioration or impaired motor functions. New therapies that would ensure better treatment results and contribute to a significant slowdown in the progression of neurodegenerative syndromes are constantly being sought. Vanadium (V), which is an element with a wide range of impacts on the mammalian organism, is at the forefront among the different metals studied for their potential therapeutic use. On the other hand, it is a well-known environmental and occupational pollutant and can exert adverse effects on human health. As a strong pro-oxidant, it can generate oxidative stress involved in neurodegeneration. Although the detrimental effects of vanadium on the CNS are relatively well recognized, the role of this metal in the pathophysiology of various neurological disorders, at realistic exposure levels in humans, is not yet well characterized. Hence, the main goal of this review is to summarize data on the neurological side effects/neurobehavioral alterations in humans, in relation to vanadium exposure, with the focus on the levels of this metal in biological fluids/brain tissues of subjects with some neurodegenerative syndromes. Data collected in the present review indicate that vanadium cannot be excluded as a factor playing a pivotal role in the etiopathogenesis of neurodegenerative illnesses, and point to the need for additional extensive epidemiological studies that will provide more evidence supporting the relationship between vanadium exposure and neurodegeneration in humans. Simultaneously, the reviewed data, clearly showing the environmental impact of vanadium on health, suggest that more attention should be paid to chronic diseases related to vanadium and to the assessment of the dose-response relationship.

In Vitro and In Vivo Studies of Antibacterial Coatings on Titanium Alloy Implants for Veterinary Application

The aim of this work was the evaluation of biological properties of hybrid coatings modified with Ag, Cu, and Zn nanoparticles (NPs) applied on TPLO medical implants by the sol-gel process. The implant coatings enriched with various concentrations of metallic NPs were investigated in the in vitro bactericidal efficacy tests against Gram+ and Gram- bacteria and pathogenic yeast. Next, the designed materials were tested on human osteosarcoma cell lines. The cells adhesion, proliferation, viability, and differentiation were investigated. The cell growth wasevaluated using SEM, and the metallic ion release was measured. The results revealed that the NPs concentration in the hybrid layers decreased with the incubation time. In the last stage, the implants were tested in vivo on six canine patients. Three months after the operation, the radiological evaluation of the performed anastomosis was carried out as well as the histopathological evaluation of tissue regeneration. The strongest bactericidal efficacy was observed for the layers containing AgNPs. Along with an increased concentration of metallic additives, a growing toxic effect was clearly observed. The most pronounced toxic effect was especially evident with the AgNPs concentration exceeding 1 mol %. In all the operated patients, no deviations were found during the follow-up examinations in the postoperative period. The low dose of AgNPs in the hybrid layer facilitated the tissue healing process. It was proven that silver nanoparticles may accelerate the bone healing process. The correct tissue reparation was observed.

Modification of TiAlV Alloys with Hybrid Layers Containing Metallic Nanoparticles Obtained by the Sol-Gel Method: Surface and Structural Properties

The aim of the work was to obtain hybrid coatings containing silver, copper, and zinc nanoparticles on the TiAlV medical alloy via a sol–gel process. The developed layers were designed to bring about a bactericidal and fungicidal effect, as well as for protection against surgical scratches during the implantation of implants used in veterinary medicine. In this work, the authors focused on evaluating the microstructure (SEM + EDS); the structure (XRD, FTIR); and the surface properties, such as wettability, free surface energy, and roughness of layers with various concentrations of metallic nanoparticles (2 and 5 mol %). Our results confirmed that the sol–gel method enables the easy manufacturing of hybrid layers endowed with different porosity values as well as various shapes and sizes of metallic nanoparticles. A higher concentration of nanoparticles was observed on the surface containing 5 mol % of metallic salts. The highest degree of homogeneity was obtained for the layers containing silver nanoparticles. In addition, the silver nanoparticles were round and had the smallest dimensions, even below 20 nm. The FTIR and XRD structural studies confirmed the presence of an organosilicon matrix containing all three types of the metallic particles. We conclude that the higher concentration of nanoparticles influenced the alloy surface parameters.

Vanadium as potential therapeutic agent for COVID-19: A focus on its antiviral, antiinflamatory, and antihyperglycemic effects

An increasing evidence suggests that vanadium compounds are novel potential drugs in the treatment of diabetes, atherosclerosis, and cancer. Vanadium has also demonstrated activities against RNA viruses and is a promising candidate for treating acute respiratory diseases. The antidiabetic, antihypertensive, lipid-lowering, cardioprotective, antineoplastic, antiviral, and other potential effects of vanadium are summarized here. Given the beneficial antihyperglycemic and antiinflammatory effects as well as the potential mechanistic link between the COVID-19 and diabetes, vanadium compounds could be considered as a complement to the prescribed treatment of COVID-19. Thus, further clinical trials are warranted to confirm these favorable effects of vanadium treatment in COVID-19 patients, which appear not to be studied yet.

LncRNA XIST Prevents Tendon Adhesion and Promotes Tendon Repair Through the miR-26a-5p/COX2 Pathway

Tendon adhesion is the biggest obstacle to repair of tendon injury. Long-chain non-coding RNA X-inactive specific transcript (lncRNA XIST) is highly expressed in populations at high risk of tendon injury. However, whether XIST participates in tendon injury and the specific mechanism remain unknown. Here, we aimed to explore the effects and underlying mechanism of XIST in tendon injury. A mouse model of tendon injury was constructed by the transection method in vivo. XIST and COX2 were highly expressed in tendon tissues of mice with tendon injury, while miR-26a-5p was lowly expressed. Fibroblasts were isolated from tendon injury mice. Overexpression of XIST promoted fibroblast proliferation and upregulated α-SMA and Collagen I protein expression, while silencing XIST indicated the opposite effects. Further dual-luciferase reporter gene assay and RIP assay verified a targeting relationship between XIST and miR-26a-5p, as well as miR-26a-5p and COX2, and XIST targeted miR-26a-5p to act on COX2 expression. miR-26a-5p inhibition and COX2 overexpression reversed the decrease in fibroblast proliferation and the downregulation of α-SMA and Collagen I expression caused by XIST silencing, while interference with si-COX2 eliminated the effects of miR-26a-5p inhibitor. This study revealed that XIST promoted fibroblast proliferation and the formation of tendon adhesion through miR-26a-5p/COX2 pathway, suggesting that XIST/miR-26a-5p/COX2 may be a potential target for the treatment of tendon injury.

Alzheimer-like cell death after vanadium pentoxide inhalation

Vanadium (V) toxicity depends on its oxidation state; it seems that vanadium pentoxide (V₂O₅) is the most toxic to the living cells. It has been reported that oral administration induces changes in motor activity and learning; in rats, I.P. administration increases lipid peroxidation levels in the cerebellum and the concentration of free radicals in the hippocampus and cerebellum. Mice that inhaled V₂O₅ presented a reduced number of tubulin+ in Leydig and Sertoli cells; it has also been reported that inhaled V₂O₅ induces loss of dendritic spines, necrosis, and hippocampus neuropil alterations; considering the direct consequence of the interaction of V with cytoskeletal components, makes us believe that V₂O₅ exposure could cause neuronal death in the hippocampus similar to that seen in Alzheimer disease. This work aimed to determine pyramidal hippocampal CA1 cytoskeletal alterations with Bielschowsky stain in rats exposed to V2O5. Male Wistar rats inhaled 0.02 M of V2O5 one h two times a week for two and six months. We found that rats, which inhaled V2O5 reached 56,57% of dead neurons after six months of inhalation; we recognize strong argyrophilic and collapsed somas and typical flame-shaped in all V-exposed rats hippocampus CA1 compared to controls. We also observe somatodendritic distortions. Axons and dendrites displayed thick dark bands replaced by noticeable thickening and nodosities and the cytoskeleton fibrillary proteins' linear traces. Our findings suggest that V2O5 inhalation induces Alzheimer-like cell death with evident cytoskeletal alterations.

Vanadium-based nanomaterials for cancer diagnosis and treatment

In the past few decades, various vanadium compounds have displayed potential in cancer treatment. However, fast clearness in the body and possible toxicity of vanadium compounds has hindered their further development. Vanadium-based nanomaterials not only overcome these limitations, but take advantage of the internal properties of vanadium in photics and magnetics, which enable them as a multimodal platform for cancer diagnosis and treatment. In this paper, we first introduced the basic biological and pharmacological functions of vanadium compounds in treating cancer. Then, the synthesis routes of three vanadium-based nanomaterials were discussed, including vanadium oxides, 2D vanadium sulfides, carbides and nitrides: V_mX_n (X = S, C, N) and water-insoluble vanadium salts. Finally, we highlighted the applications of these vanadium-based nanomaterials as tumor therapeutic and diagnostic agents.

Vanadium(IV)-diamine complex with hypoglycemic activity and a reduction in testicular atrophy

The insulin enhancing activity, histological analysis and, testicular degeneration by a V^IVO-complex containing the 2,2'-(ethane-1,2-diylbis(azanediyl))diethanolate ligand, VO^IV(C₆H₁₄N₂O₂-κ²N,κ²O), abbreviated V^IVO(BHED), were investigated in diabetic male Wistar rats. The complex was administered by oral gavage of freshly prepared solutions of vanadium complex. Biological studies demonstrated that the vanadium complex normalized the elevated glucose levels in male Wistar rats with streptozotocin-induced diabetes and these compounds also avoided common responses in diabetic animals such as weight loss and reduction in the size of the epididymis, prostate, testis and seminal gland. The ⁵¹V NMR and EPR studies showed the formation of V^IVO(BHED) and the oxidation product [V^VO₂BHED]^- with two possible decomposition pathways. In summary, these studies demonstrate that the V^IVO(BHED) complex or its decomposition products show similar effects as insulin in decreasing elevated blood glucose levels.

Mini review-vanadium-induced neurotoxicity and possible targets

Vanadium, a transition metal, ubiquitous in nature is known to have therapeutic effect as well as toxic effect. It is known to possess antidiabetic, antitumor and antiparasitic activity. However, on long term exposure, it produces neurotoxicity which may result in memory impairment. The possible mechanism known to cause neurotoxicity suggested is oxidative stress and inflammation of neuronal cells. The present review has focused on discussing the role of protein P38 mitogen-activated protein kinase and oxidative stress as possible targets to treat vanadium-induced neurotoxicity.

Maternal Heavy Metal Exposure, Thyroid Hormones, and Birth Outcomes: A Prospective Cohort Study

CONTEXT

Maternal thyroid hormones during pregnancy play a critical role in fetal development. However, whether maternal heavy metal exposure affects their thyroid hormones and the effects on fetal growth are still unclear.

OBJECTIVE

To explore the effect of heavy metal exposure on maternal thyroid hormones and the potential mediation role of thyroid hormones on birth outcomes.

METHODS

Concentrations of heavy metals in urine samples and thyroid hormones in blood samples of 675 pregnant women were measured during early pregnancy in a cohort study conducted in China. Multivariable linear regressions were applied to explore the associations of maternal urinary heavy metal levels with both maternal thyroid hormones and birth outcomes. Mediation analyses were performed to assess the mediation role of thyroid hormones in these associations.

RESULTS

Maternal urinary vanadium (V) exhibited an inverse association with free T3 (FT3) and FT3/free T4 (FT4) ratio levels. Urinary arsenic (As) and lead (Pb) had inverse relationships with FT3. We also observed the positive associations of maternal FT3 and FT3/FT4 ratio with birthweight. The mediation analyses suggested that 5.33% to 30.57% of the associations among V, As, and Pb levels and birth size might be mediated by maternal FT3 or FT3/FT4 ratio.

CONCLUSIONS

We have shown that maternal exposures to V, As, and Pb at early pregnancy were associated with decreased maternal FT3 or FT3/FT4 ratio, which might contribute to reduced birthweight. Mediation analyses indicated that maternal thyroid hormone was a possible mediator of the association between urinary heavy metals and birth size.

Vanadium Compounds as Enzyme Inhibitors with a Focus on Anticancer Effects

Vanadium salts and coordination compounds have desirable cellular anticancer effects, and although they have been investigated in detail as a potential treatment for diabetes, less attention has been given to the anticancer effects. The inhibition of some signal transduction enzymes is known, and studies of the metabolism and activation pathways both in vitro and in vivo are important for future investigations and development of vanadium's role as a new potential drug. In addition, a new approach has demonstrated that the enhancement of oncolytic viruses using vanadium salts and coordination complexes for immunotherapy is very promising. Some differences exist between this approach and current antidiabetic and anticancer studies because vanadium(iv) complexes have been found to be most potent in the latter approach, but the few compounds investigated with oncolytic viruses show that vanadium(v) systems are more effective. We conclude that recent studies demonstrate effects on signal transduction enzymes and anticancer pathways, thus suggesting potential applications of vanadium as anticancer agents in the future both as standalone treatments as well as combination therapies.

Vanadate oxidative and apoptotic effects are mediated by the MAPK-Nrf2 pathway in layer oviduct magnum epithelial cells

Vanadium is a metal of high physiological, environmental and industrial importance. However, vanadium-induced oxidative stress can reduce the egg quality of poultry, and be potentially harmful to humans, and the underlying mechanism is not clear. In this study, we investigated the underlying relationship between the oxidant-sensitive mitogen-activated protein kinase (MAPK) signaling pathway and vanadium-induced oxidative stress in oviduct magnum epithelial (OME) cells. Cultured OME cells were treated with 100 μmol L^-1 vanadium and/or MAPK inhibitors [P38 MAPK inhibitor, SB203580; extracellular regulated protein kinase 1 and 2 (ERK1/2) inhibitor, U0126; c-JUN N-terminal kinases (JNK) inhibitor, SP600125]. Cell viability, apoptosis, and generation of reactive oxygen species (ROS) were assessed using flow cytometry. The expression of oxidative stress-related genes and their proteins was measured by reverse transcription-polymerase chain reaction and western blotting. Vanadium treatment reduced cell viability, whereas pretreated OME cells with SB203580 and U0126 prevented the reducing effect of vanadium on cell viability (P < 0.05). Likewise, MAPK inhibitors effectively suppressed vanadium-induced apoptosis and ROS generation (P < 0.05). In the OME cells treated with vanadium, SB203580 (P < 0.05) and SP600125 (P = 0.08) increased catalase activity by 89.3% and 55.3%; SB203580 and U0126 increased (P < 0.05) glutathione peroxidase activity by 44.9% and 51.1%, respectively. Incubation of OME cells with MAPK inhibitors also prevents malondialdehyde concentration increase and lactic dehydrogenase activity decrease in response to vanadium (P < 0.05). Vanadium downregulated P38, ERK1/2, JNK, Nrf2, sMaf, GCLC, NQO1 and HO-1 mRNA expression (P < 0.05). In contrast, inhibition of JNK with SP600125 upregulated P38, ERK1/2, JNK, Nrf2, GCLC and HO-1 mRNA expression (P < 0.05); inhibition of P38 with SB203580 upregulated JNK, NQO1 and HO-1 mRNA expression (P < 0.05); and inhibition of ERK1/2 with U0126 upregulated ERK1/2, GCLC and HO-1 mRNA expression (P < 0.05). Moreover, phosphorylation of P38, ERK1/2, JNK, and Nrf2 proteins was enhanced by V incubation; however, SP600125 blocked the phosphorylation of these proteins, whereas SB203580 blocked the phosphorylation of P38 and Nrf2. These results indicate that vanadium inducing oxidative stress in OME cells might be, at least, associated with the phosphorylation of the P38MAPK/JNK-Nrf2 pathway, which reduces the expression of phase II detoxifying enzymes.

Effects of sodium tungstate and vanadyl sulphate on the liberation of prostanoids of the mesenteric vascular bed in diabetic rats

The loss of the modulator role of the endothelium could be involved in the pathogenesis of diabetic vascular complications. Transition metal compounds, such as tungsten and vanadium, have been proposed as possible agents in the treatment of diabetes by simulating the effects of insulin. The mesenteric vascular bed intervenes in vascular resistance and is a source of vasoactive compounds, such as prostanoids. The aim of this work was to study the effects of sodium tungstate and vanadyl sulphate treatments on the metabolic parameters and the release of prostanoids of the mesenteric vascular bed in an experimental model of Streptozotocin-induced diabetes. In diabetic rats, a significant increase was observed in plasma levels of glucose, triglycerides and total cholesterol. On the other hand, there was a significant reduction in the release of vasodilator prostanoids, such as prostacyclin and prostaglandin E₂ and vasoconstrictor thromboxane A₂ through the mesenteric vascular bed. Both sodium tungstate and vanadyl sulphate normalised glycaemia, triglyceridaemia and cholesterolaemia in rats diabetics. On the other hand, only treatment with sodium tungstate reversed the reduction in the release of vasodilator prostanoids, improving in diabetic animals the prostacyclin/thromboxane ratio, an indicator of vascular dysfunction. In conclusion, unlike vanadyl sulphate, sodium tungstate is shown to be more effective in controlling metabolic changes and the production of vasodilator prostanoids observed in experimental diabetes induced by streptozotocin.

Trends in vanadium neurotoxicity

Vanadium, atomic number 23, is a transition metal widely distributed in nature. It is a major contaminant of fossil fuels and is widely used in industry as catalysts, in welding, and making steel alloys. Over the years, vanadium compounds have been generating interests due to their use as therapeutic agents in the control of diabetes, tuberculosis, and some neoplasms. However, the toxicity of vanadium compounds is well documented in literature with occupational exposure of workers in vanadium allied industries, environmental pollution from combustion of fossil fuels and industrial exhausts receiving concerns as major sources of toxicity and a likely predisposing factor in the aetiopathogenesis of neurodegenerative diseases. A lot has been done to understand the neurotoxic effects of vanadium, its mechanisms of action and possible antidotes. Sequel to our review of the subject in 2011, this present review is to detail the recent insights gained in vanadium neurotoxicity.

Primary study on the toxic mechanism of vanadyl trehalose in Kunming mice

It has been shown that vanadyl trehalose could lower blood glucose but show mild toxicity to the stomach and intestine in diabetic Kunming mice. We analysed antioxidant levels, pro-inflammatory cytokine expression, apoptosis factors and intestinal microflora alteration to explore the mechanism of vanadyl trehalose toxicity in Kunming mice. The results revealed that oral administration of vanadyl trehalose at tested dose caused significant changes in oxidative stress factor (MDA levels elevated but SOD and T-AOC decreased), expression of inflammatory factor (IL-1β, COX-2, TNF-α and iNOS increased), and apoptosis factor (Bcl-2/Bax decreased and caspase-3 increased), and intestinal microflora dysbiosis (the number of Enterobacteriaceae and Enterococcus increased and Lactobacillus and Bifidobacterium decreased) relative to the control of Kunming mice. These results suggest that the toxic mechanisms of vanadyl trehalose on the stomach and intestine likely involve activation of the oxidative stress system, increased inflammatory response, promotion of apoptosis and the disruption of the normal intestinal microflora.

Vanadium Compounds as PTP Inhibitors

Phosphotyrosine signaling is regulated by the opposing actions of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). Here we discuss the potential of vanadium derivatives as PTP enzyme inhibitors and metallotherapeutics. We describe how vanadate in the V oxidized state is thought to inhibit PTPs, thus acting as a pan-inhibitor of this enzyme superfamily. We discuss recent developments in the biological and biochemical actions of more complex vanadium derivatives, including decavanadate and in particular the growing number of oxidovanadium compounds with organic ligands. Pre-clinical studies involving these compounds are discussed in the anti-diabetic and anti-cancer contexts. Although in many cases PTP inhibition has been implicated, it is also clear that many such compounds have further biochemical effects in cells. There also remain concerns surrounding off-target toxicities and long-term use of vanadium compounds in vivo in humans, hindering their progress through clinical trials. Despite these current misgivings, interest in these chemicals continues and many believe they could still have therapeutic potential. If so, we argue that this field would benefit from greater focus on improving the delivery and tissue targeting of vanadium compounds in order to minimize off-target toxicities. This may then harness their full therapeutic potential.

Oxidative Stress as a Mechanism Involved in Kidney Damage After Subchronic Exposure to Vanadium Inhalation and Oral Sweetened Beverages in a Mouse Model

Kidney diseases have notably increased in the last few years. This is partially explained by the increase in metabolic syndrome, diabetes, and systemic blood hypertension. However, there is a segment of the population that has neither of the previous risk factors, yet suffers kidney damage. Exposure to atmospheric pollutants has been suggested as a possible risk factor. Air-suspended particles carry on their surface a variety of fuel combustion-related residues such as metals, and vanadium is one of these. Vanadium might produce oxidative stress resulting in the damage of some organs such as the kidney. Additionally, in countries like Mexico, the ingestion of sweetened beverages is a major issue; whether these beverages alone are responsible for direct kidney damage or whether their ingestion promotes the progression of an existing renal damage generates controversy. In this study, we report the combined effect of vanadium inhalation and sweetened beverages ingestion in a mouse model. Forty CD-1 male mice were distributed in 4 groups: control, vanadium inhalation, 30% sucrose in drinking water, and vanadium inhalation plus sucrose 30% in drinking water. Our results support that vanadium inhalation and the ingestion of 30% sucrose induce functional and histological kidney damage and an increase in oxidative stress biomarkers, which were higher in the combined effect of vanadium plus 30% sucrose. The results also support that the ingestion of 30% sucrose alone without hyperglycemia also produces kidney damage.

Resveratrol Ameliorates Tau Hyperphosphorylation at Ser396 Site and Oxidative Damage in Rat Hippocampal Slices Exposed to Vanadate: Implication of ERK1/2 and GSK-3β Signaling Cascades

The objective of this study was to investigate the effect of resveratrol (a natural polyphenolic phytostilbene) on tau hyperphosphorylation and oxidative damage induced by sodium orthovanadate (Na₃VO₄), the prevalent species of vanadium (vanadate), in rat hippocampal slices. Our results showed that resveratrol significantly inhibited Na₃VO₄-induced hyperphosphorylation of tau at the Ser396 (p-S396-tau) site, which is upregulated in the hippocampus of Alzheimer's disease (AD) brains and principally linked to AD-associated cognitive dysfunction. Subsequent mechanistic studies revealed that reduction of ERK1/2 activation was involved in the inhibitory effect of resveratrol by inhibiting the ERK1/2 pathway with SL327 mimicking the aforementioned effect of resveratrol. Moreover, resveratrol potently induced GSK-3β Ser9 phosphorylation and reduced Na₃VO₄-induced p-S396-tau levels, which were markedly replicated by pharmacologic inhibition of GSK-3β with LiCl. These results indicate that resveratrol could suppress Na₃VO₄-induced p-S396-tau levels via downregulating ERK1/2 and GSK-3β signaling cascades in rat hippocampal slices. In addition, resveratrol diminished the increased extracellular reactive oxygen species generation and hippocampal toxicity upon long-term exposure to Na₃VO₄ or FeCl₂. Our findings strongly support the notion that resveratrol may serve as a potential nutraceutical agent for AD.

Association of adverse birth outcomes with prenatal exposure to vanadium: a population-based cohort study

BACKGROUND

Vanadium, an important pollutant produced from anthropogenic activities, has been suggested to be embryotoxic and fetotoxic in animal studies. However, little is known about its effects on humans. We aimed to assess the association of prenatal exposure to vanadium with the risk of adverse birth outcomes in babies born to women in China.

METHODS

For this population-based cohort study, the Healthy Baby Cohort, women were recruited from three cities in Hubei Province, China. Women included in this analysis were recruited from Wuhan Women and Children Medical Care Center, Wuhan. We measured urinary concentrations of vanadium and other metals simultaneously using inductively coupled plasma mass spectrometry. We used multivariable logistic regressions, with adjustment for potential confounders, to estimate the associations of natural logarithm transformed creatinine-corrected urinary vanadium (Ln-vanadium) concentrations as continuous variables and categorised into quartiles (Q; Q1: ≤0·84 μg/g creatinine, Q2: 0·84-1·40 μg/g creatinine, Q3: 1·40-2·96 μg/g creatinine, Q4: >2·96 μg/g creatinine, with the lowest quartile set as reference) with preterm delivery, early-term delivery, low birthweight, and being small for gestational age. We applied restricted cubic spline models to evaluate the dose-response relationships.

FINDINGS

Data from 7297 women recruited between Sept 22, 2012, and Oct 22, 2014, were included in this study. Urinary Ln-vanadium concentrations showed non-linear dose-response relationships with risk of preterm delivery (S-shaped, p<0·0001) and low birthweight (J-shaped, p=0·0001); the adjusted odds ratios (ORs) for increasing quartiles of urinary vanadium were 1·76 (95% CI 1·05-2·95) for Q2, 3·17 (1·96-5·14) for Q3, and 8·86 (5·66-13·86) for Q4 for preterm delivery, and 2·29 (95% CI 1·08-4·84) for Q2, 3·22 (1·58-6·58) for Q3, and 3·56 (1·79-7·10) for Q4 for low birthweight. Ln-vanadium concentrations were linearly associated with the risk of early-term delivery (linear, p<0·0001) and being small for gestational age (linear, p=0·0027), with adjusted ORs of 1·15 (95% CI 1·10-1·21) for early-term delivery and 1·12 (1·04-1·21) for being small for gestational age per unit increase in Ln-vanadium concentrations.

INTERPRETATION

Our findings reveal a relationship between prenatal exposure to higher levels of vanadium and increased risk of adverse birth outcomes, suggesting that vanadium might be a potential toxic metal for human beings. Further studies are needed to replicate the observed associations and investigate the interaction effects of prenatal exposure to different metals on adverse birth outcomes.

FUNDING

National Key R&D Plan of China, National Natural Science Foundation of China, and Fundamental Research Funds for the Central Universities, Key Laboratory of Environment and Health.

Sodium orthovanadate suppresses palmitate-induced cardiomyocyte apoptosis by regulation of the JAK2/STAT3 signaling pathway

Elevated circulatory free fatty acids (FFAs) especially saturated FFAs, such as palmitate (PA), are detrimental to the heart. However, mechanisms responsible for this phenomenon remain unknown. Here, the role of JAK2/STAT3 in PA-induced cytotoxicity was investigated in cardiomyocytes. We demonstrate that PA suppressed the JAK2/STAT3 pathway by dephosphorylation of JAK2 (Y1007/1008) and STAT3 (Y705), and thus blocked the translocation of STAT3 into the nucleus. Conversely, phosphorylation of S727, another phosphorylated site of STAT3, was increased in response to PA treatment. Pretreatment of JNK inhibitor, but not p38 MAPK inhibitor, inhibited STAT3 (S727) activation induced by PA and rescued the phosphorylation of STAT3 (Y705). The data suggested that JNK may be another upstream factor regulating STAT3, and verified the important function of P-STAT3 (Y705) in PA-induced cardiomyocyte apoptosis. Sodium orthovanadate (SOV), a protein tyrosine phosphatase inhibitor, obviously inhibited PA-induced apoptosis by restoring JAK2/STAT3 pathways. This effect was diminished by STAT3 inhibitor Stattic. Collectively, our data suggested a novel mechanism that the inhibition of JAK2/STAT3 activation was responsible for palmitic lipotoxicity and SOV may act as a potential therapeutic agent by targeting JAK2/STAT3 in lipotoxic cardiomyopathy treatment.

Vanadium toxicity in the thymic development

The purpose of this study was to define the toxic effects of vanadium on thymic development in broilers fed on diets supplemented with 0, 5, 15, 30, 45 and 60 mg/kg of vanadium for 42 days. We examined the changes of relative weigh, cell cycle phase, apoptotic cells, and protein expression of Bcl-2, Bax, and caspase-3 in the thymus by the methods of flow cytometry, TUNEL (terminal-deoxynucleotidyl transferase mediated nick end labeling) and immunohistochemistry. The results showed that dietary high vanadium (30 mg/kg, 45 mg/kg and 60 mg/kg) caused the toxic effects on thymic development, which was characterized by decreasing relative weigh, increasing G0/G1 phase (a prolonged nondividing state), reducing S phase (DNA replication) and proliferating index (PI), and increasing percentages of apoptotic thymocytes. Concurrently, the protein expression levels of Bax and caspase-3 were increased, and protein expression levels of Bcl-2 were decreased. The thymic development suppression caused by dietary high vanadium further leads to inhibitive effects on T lymphocyte maturity and activity, and cellular immune function. The above-mentioned results provide new evidences for further understanding the vanadium immunotoxicity. In contrast, dietary 5 mg/kg vanadium promoted the thymic development by increasing relative weigh, decreasing G0/G1 phase, increasing S phase and PI, and reducing percentages of apoptotic thymocytes when compared to the control group and high vanadium groups.