Vanadium: Risks and possible benefits in the light of a comprehensive overview of its pharmacotoxicological mechanisms and multi-applications with a summary of further research trends

Influence of temperature on the equilibria of oxidovanadium(IV) complexes in solution

The equilibria in the solution of three different oxidovanadium(IV) complexes, VO(dhp)₂ (dhp = 1,2-dimethyl-3-hydroxy-4(1H)-pyridinonato), VO(ma)₂ (ma = maltolato) and VO(pic)₂(H₂O) (pic = picolinato), were examined in the temperature range of 120-352 K through a combination of instrumental (EPR spectroscopy) and computational techniques (DFT methods). The results revealed that a general equilibrium exists: VOL₂ + H₂O ⇄ cis-VOL₂(H₂O) ⇄ trans-VOL₂(H₂O), where cis and trans refer to the relative position of H₂O and the oxido ligand. The equilibrium is more or less shifted to the right depending on the ligand, the temperature, the ionic strength and the coordinating properties of the solvent. With VO(dhp)₂, only the square pyramidal species exists at 298 K in aqueous solution, while at 120 K the cis- and trans-VO(dhp)₂(H₂O) species are also present. The complex of maltol exists almost exclusively in the form cis-VO(ma)₂(H₂O) in aqueous solution at 298 K, while the trans species can be revealed only at higher temperatures, where the EPR linewidth significantly decreases. The equilibria involving 1-methylimidazole (MeIm), a model for the side chain His coordination, are also influenced by temperature, with its coordination being favored by decreasing the temperature. The implications of these results in the study of the (vanadium complex)-protein systems are discussed and the interaction with myoglobin (Mb) is examined as a representative example.

Alzheimer's Disease and Diabetes Mellitus in Comparison: The Therapeutic Efficacy of the Vanadium Compound

Alzheimer’s disease (AD) is an intractable neurodegenerative disease that leads to dementia, primarily in elderly people. The neurotoxicity of amyloid-beta (Aβ) and tau protein has been demonstrated over the last two decades. In line with these findings, several etiological hypotheses of AD have been proposed, including the amyloid cascade hypothesis, the oxidative stress hypothesis, the inflammatory hypothesis, the cholinergic hypothesis, et al. In the meantime, great efforts had been made in developing effective drugs for AD. However, the clinical efficacy of the drugs that were approved by the US Food and Drug Association (FDA) to date were determined only mild/moderate. We recently adopted a vanadium compound bis(ethylmaltolato)-oxidovanadium (IV) (BEOV), which was originally used for curing diabetes mellitus (DM), to treat AD in a mouse model. It was shown that BEOV effectively reduced the Aβ level, ameliorated the inflammation in brains of the AD mice, and improved the spatial learning and memory activities of the AD mice. These finding encouraged us to further examine the mechanisms underlying the therapeutic effects of BEOV in AD. In this review, we summarized the achievement of vanadium compounds in medical studies and investigated the prospect of BEOV in AD and DM treatment.

Immunological Mechanisms of Metal Allergies and the Nickel-Specific TCR-pMHC Interface

Besides having physiological functions and general toxic effects, many metal ions can cause allergic reactions in humans. We here review the immune events involved in the mediation of metal allergies. We focus on nickel (Ni), cobalt (Co) and palladium (Pd), because these allergens are among the most prevalent sensitizers (Ni, Co) and immediate neighbors in the periodic table of the chemical elements. Co-sensitization between Ni and the other two metals is frequent while the knowledge on a possible immunological cross-reactivity using in vivo and in vitro approaches remains limited. At the center of an allergic reaction lies the capability of a metal allergen to form T cell epitopes that are recognized by specific T cell receptors (TCR). Technological advances such as activation-induced marker assays and TCR high-throughput sequencing recently provided new insights into the interaction of Ni2+ with the αβ TCR-peptide-major histocompatibility complex (pMHC) interface. Ni2+ functionally binds to the TCR gene segment TRAV9-2 or a histidine in the complementarity determining region 3 (CDR3), the main antigen binding region. Thus, we overview known, newly identified and hypothesized mechanisms of metal-specific T cell activation and discuss current knowledge on cross-reactivity.

Thermodynamic Study of Oxidovanadium(IV) with Kojic Acid Derivatives: A Multi-Technique Approach

The good chelating properties of hydroxypyrone (HPO) derivatives towards oxidovanadium(IV) cation, VIVO2+, constitute the precondition for the development of new insulin-mimetic and anticancer compounds. In the present work, we examined the VIVO2+ complex formation equilibria of two kojic acid (KA) derivatives, L4 and L9, structurally constituted by two kojic acid units linked in position 6 through methylene diamine and diethyl-ethylenediamine, respectively. These chemical systems have been characterized in solution by the combined use of various complementary techniques, as UV-vis spectrophotometry, potentiometry, NMR and EPR spectroscopy, ESI-MS spectrometry, and DFT calculations. The thermodynamic approach allowed proposing a chemical coordination model and the calculation of the complex formation constants. Both ligands L4 and L9 form 1:1 binuclear complexes at acidic and physiological pHs, with various protonation degrees in which two KA units coordinate each VIVO2+ ion. The joined use of different techniques allowed reaching a coherent vision of the complexation models of the two ligands toward oxidovanadium(IV) ion in aqueous solution. The high stability of the formed species and the binuclear structure may favor their biological action, and represent a good starting point toward the design of new pharmacologically active vanadium species.

Albumin-EDTA-Vanadium Is a Powerful Anti-Proliferative Agent, Following Entrance into Glioma Cells via Caveolae-Mediated Endocytosis

Human serum albumin (HSA) is efficiently taken up by cancer cells as a source of carbon and energy. In this study, we prepared a monomodified derivative of HSA covalently linked to an EDTA derivative and investigated its efficacy to shuttle weakly anti-proliferative EDTA associating ligands such as vanadium, into a cancer cell line. HSA-S-MAL-(CH₂)₂-NH-CO-EDTA was found to associate both with the vanadium anion (+5) and the vanadium cation (+4) with more than thrice the associating affinity of those ligands toward EDTA. Both conjugates internalized into glioma tumor cell line via caveolae-mediated endocytosis pathway and showed potent anti-proliferative capacities. IC₅₀ values were in the range of 0.2 to 0.3 µM, potentiating the anti-proliferative efficacies of vanadium (+4) and vanadium (+5) twenty to thirty fold, respectively. HSA-EDTA-VO⁺⁺ in particular is a cancer permeable prodrug conjugate. The associated vanadium (+4) is not released, nor is it active anti-proliferatively prior to its engagement with the cancerous cells. The bound vanadium (+4) dissociates from the conjugate under acidic conditions with half maximal value at pH 5.8. In conclusion, the anti-proliferative activity feature of vanadium can be amplified and directed toward a cancer cell line. This is accomplished using a specially designed HSA-EDTA-shuttling vehicle, enabling vanadium to be anti-proliferatively active at the low micromolar range of concentration.

Prenatal and postnatal exposure to vanadium and the immune function of children

BACKGROUND

The immunotoxicity induced by vanadium exposure have been reported in some toxicology researches. However, evidence from population-based epidemiological studies was lacking.

METHODS

This study was conducted to assess the associations between prenatal and postnatal exposure to vanadium and immune function of children. A total of 407 pre-school aged children were followed, whose peripheral blood was collected for T lymphocyte subsets and inflammatory cytokines analysis, as well as vanadium concentration measurement. Maternal urine samples were also collected to measure vanadium concentration. We used generalized linear models to evaluate the associations of maternal and children vanadium concentration with children's immune function. Stratification analysis was further conducted to explore the potential gender-specific effects.

RESULTS

The geometric means of vanadium concentration in maternal urine and children plasma were 0.85 and 1.12 μg/L, respectively. Maternal urinary vanadium was inversely associated with the percentage of CD3⁺CD4⁺ cells [-5.53 % (-10.38 %, -0.41 %)] and absolute counts of CD3⁺ cells [-2.43 % (-5.05 %, 0.25 %)], and we only observed significant negative associations in males when stratifying by fetal gender. Children plasma vanadium was also associated with reduced absolute counts of CD3⁺ cells [-5.25 % (-9.57 %, -0.73 %)], but gender-specific effects were not observed. No significant associations of vanadium exposure with cytokines were found.

CONCLUSIONS

Prenatal and postnatal exposure to vanadium had suppressive impacts on childhood cellular immune. Further studies are needed to confirm our findings.

Performance and mechanisms for V(v) bio-reduction by straw: key influencing factors

A high concentration of vanadium [V(v)] in groundwater is extremely harmful for humans. Weak movability and low toxicity after microbial V(v) reduction have attracted remarkable attention, especially for using solid carbon sources. However, the influencing factors remain unclear. In this study, the initial V(v) concentration, inocula amount and straw dosage were examined to ascertain the mechanisms behind them. Increasing the initial V(v) concentration led to the decrease of the V(v) removal efficiency, which was also positively correlated with the straw dosage within a certain range. The initial sludge amount was not a main factor affecting microbial V(v) removal in this study. With the initial amount of 10 mg L-1 V(v), 25 mL initial inocula and 5 g straw, 88.2% of V(v) was removed. According to the dissolved organic matter (DOM) analysis results, microbial activity prevailed in groups with higher V(v) removal efficiency, indicating that the V(v) bio-reduction was attributed to the microbial activity, which was considered a major factor. Functional species as unclassified_f_Enterobacteriaceae presumably contributed to the V(v) bioreduction, with upregulated ABC transporter genes and enzymes.

Development, Validation and Application of an ICP-SFMS Method for the Determination of Metals in Protein Powder Samples, Sourced in Ireland, with Risk Assessment for Irish Consumers

A method has been developed, optimised and validated to analyse protein powder supplements on an inductively coupled plasma-sector field mass spectrometer (ICP-SFMS), with reference to ICH Guideline Q2 Validation of Analytical Procedures: Text and Methodology. This method was used in the assessment of twenty-one (n = 21) elements (Al, Au, Ba, Be, Bi, Cd, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Pb, Pt, Sn, Ti, Tl, V) to evaluate the safety of thirty-six (n = 36) protein powder samples that were commercially available in the Irish marketplace in 2016/2017. Using the determined concentrations of elements in samples (µg·kg-1), a human health risk assessment was carried out to evaluate the potential carcinogenic and other risks to consumers of these products. While the concentrations of potentially toxic elements were found to be at acceptable levels, the results suggest that excessive and prolonged use of some of these products may place consumers at a slightly elevated risk for developing cancer or other negative health impacts throughout their lifetimes. Thus, the excessive use of these products is to be cautioned, and consumers are encouraged to follow manufacturer serving recommendations.

Cytotoxicity and genotoxicity of low-dose vanadium dioxide nanoparticles to lung cells following long-term exposure

Vanadium dioxide nanoparticles (VO₂ NPs) have been massively produced and widely applied due to their excellent metal-insulator transition property, making it extremely urgent to evaluate their safety, especially for low-dose long-term respiratory occupational exposure. Here, we report a comprehensive cytotoxicity and genotoxicity study on VO₂ NPs to lung cell lines A549 and BEAS-2B following a long-term exposure. A commercial VO₂ NP, S-VO₂, was used to treat BEAS-2B (0.15-0.6 μg/mL) and A549 (0.3-1.2 μg/mL) cells for four exposure cycles, and each exposure cycle lasted for 4 consecutive days; then various bioassays were performed after each cycle. Significant proliferation inhibition was observed in both cell lines after long-term exposure of S-VO₂ at low doses that did not cause apparent acute cytotoxicity; however, the genotoxicity of S-VO₂, characterized by DNA damage and micronuclei, was only observed in A549 cells. These adverse effects of S-VO₂ were exposure time-, dose- and cell-dependent, and closely related to the solubility of S-VO₂. The oxidative stress in cells, i.e., enhanced reactive oxygen species (ROS) generation and suppressed reduced glutathione, was the main toxicity mechanism of S-VO₂. The ROS-associated mitochondrial damage and DNA damage led to the genotoxicity, and cell proliferation retard, resulting in the cellular viability loss. Our results highlight the importance and urgent necessity of the investigation on the long-term toxicity of VO₂ NPs.

Bis(ethylmaltolato)oxidovanadium (IV) alleviates neuronal apoptosis through regulating peroxisome proliferator-activated receptor γ in a triple transgenic animal model of Alzheimer's disease

Endoplasmic reticulum stress (ER stress) plays a critical role in neuronal apoptosis along with the aggravation of Alzheimer's disease (AD). Nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) is a ligand-activated transcription factor that is involved in regulating ER stress in Alzheimer's disease (AD), therefore, this protein could be a promising therapeutic target for AD. Vanadium compounds, such as vanadyl acetylacetonate, sodium metavanadate and bis(maltolato)oxovanadium, are well-known as puissant PPARγ modulators. Thus, we are curious whether bis(ethylmaltolato)oxidovanadium (IV) (BEOV) can ameliorate ER stress and subsequent neuronal apoptosis by regulating PPARγ in AD models. To this end, we determined the effect of BEOV on behavioral performance, ER stress and neuronal apoptosis in the triple transgenic mouse AD model (3×Tg-AD). Our results showed that BEOV improved cognitive abilities and reduced the ER stress- and apoptosis-associated proteins in the brains of 3×Tg-AD mice. In vitro administration of BEOV in primary hippocampal neurons and N2asw cells achieved similar results in repressing ER stress. In addition, cotreatment with GW9662 (an antagonist of PPARγ) effectively blocked these neuroprotective effects of BEOV, which provided strong evidence that PPARγ-dependent signaling plays a key role in protecting against ER stress and neuronal apoptosis in AD. In conclusion, our data demonstrated that BEOV alleviated neuronal apoptosis triggered by ER stress by regulating PPARγ in a 3×Tg-AD model.

Bis(ethylmaltolato)oxidovanadium (IV) attenuates amyloid-beta-mediated neuroinflammation by inhibiting NF-κB signaling pathway via a PPARγ-dependent mechanism

Neuroinflammation plays a pivotal role in the pathophysiology of neurodegenerative diseases, such as Parkinson's disease and Alzheimer's disease. During brain neuroinflammation, activated microglial cells resulting from amyloid-beta (Aβ) overload trigger toxic proinflammatory responses. Bis(ethylmaltolato)oxidovanadium (BEOV) (IV), an important vanadium compound, has been reported to have anti-diabetic, anti-cancer, and neuroprotective effects, but its anti-inflammatory property has rarely been investigated. In the present study, the inhibitory effects of BEOV on neuroinflammation were revealed in both Aβ-stimulated BV2 microglial cell line and APPswe/PS1E9 transgenic mouse brain. BEOV administration significantly decreased the levels of tumor necrosis factor-α, interleukin-6, interleukin-1β, inducible nitric oxide synthase, and cyclooxygenase-2 both in the hippocampus of APPswe/PS1E9 mice and in the Aβ-stimulated BV2 microglia. Furthermore, BEOV suppressed the Aβ-induced activation of nuclear factor-κB (NF-κB) signaling and upregulated the protein expression level of peroxisome proliferator-activated receptor gamma (PPARγ) in a dose-dependent manner. PPARγ inhibitor GW9662 could eliminate the effect of BEOV on Aβ-induced NF-κB activation and proinflammatory mediator production. Taken altogether, these findings suggested that BEOV ameliorates Aβ-stimulated neuroinflammation by inhibiting NF-κB signaling pathway through a PPARγ-dependent mechanism.

Challenge of diabetes mellitus and researchers’ contributions to its control

The aim of this review study was to assess the past significant events on diabetes mellitus, transformations that took place over the years in the medical records of treatment, countries involved, and the researchers who brought about the revolutions. This study used the content analysis to report the existence of diabetes mellitus and the treatments provided by researchers to control it. The focus was mainly on three main types of diabetes (type 1, type 2, and type 3 diabetes). Ethical consideration has also helped to boost diabetic studies globally. The research has a history path from pharmaceuticals of organic-based drugs to metal-based drugs with their nanoparticles in addition to the impacts of nanomedicine, biosensors, and telemedicine. Ongoing and future studies in alternative medicine such as vanadium nanoparticles (metal nanoparticles) are promising.

Acute Toxicity Evaluation of Non-Innocent Oxidovanadium(V) Schiff Base Complex

The vanadium(V) complexes have been investigated as potential anticancer agents which makes it essential to evaluate their toxicity for safe use in the clinic. The large-scale synthesis and the acute oral toxicity in mice of the oxidovanadium(V) Schiff base catecholate complex, abbreviated as [VO(HSHED)dtb] containing a redox-active ligand with tridentate Schiff base (HSHED = N-(salicylideneaminato)-N’-(2-hydroxyethyl)-1,2-ethylenediamine) and dtb = 3,5-di-(t-butyl)catechol ligands were carried out. The body weight, food consumption, water intake as well biomarkers of liver and kidney toxicity of the [VO(HSHED)dtb] were compared to the precursors, sodium orthovanadate, and free ligand. The 10-fold scale-up synthesis of the oxidovanadium(V) complex resulting in the preparation of material in improved yield leading to 2–3 g (79%) material suitable for investigating the toxicity of vanadium complex. No evidence of toxicity was observed in animals when acutely exposed to a single dose of 300 mg/kg for 14 days. The toxicological results obtained with biochemical and hematological analyses did not show significant changes in kidney and liver parameters when compared with reference values. The low oral acute toxicity of the [VO(HSHED)dtb] is attributed to redox chemistry taking place under biological conditions combined with the hydrolytic stability of the oxidovanadium(V) complex. These results document the design of oxidovanadium(V) complexes that have low toxicity but still are antioxidant and anticancer agents.

Vanadium and Melanoma: A Systematic Review

The application of metals in biological systems has been a rapidly growing branch of science. Vanadium has been investigated and reported as an anticancer agent. Melanoma is the most aggressive type of skin cancer, the incidence of which has been increasing annually worldwide. It is of paramount importance to identify novel pharmacological agents for melanoma treatment. Herein, a systematic review of publications including “Melanoma and Vanadium” was performed. Nine vanadium articles in several melanoma cells lines such as human A375, human CN-mel and murine B16F10, as well as in vivo studies, are described. Vanadium-based compounds with anticancer activity against melanoma include: (1) oxidovanadium(IV); (2) XMenes; (3) vanadium pentoxide, (4) oxidovanadium(IV) pyridinonate compounds; (5) vanadate; (6) polysaccharides vanadium(IV/V) complexes; (7) mixed-metal binuclear ruthenium(II)–vanadium(IV) complexes; (8) pyridoxal-based oxidovanadium(IV) complexes and (9) functionalized nanoparticles of yttrium vanadate doped with europium. Vanadium compounds and/or vanadium materials show potential anticancer activities that may be used as a useful approach to treat melanoma.

Synthesis and Characterization of Novel Chickpea Protein Hydrolysate-Vanadium Complexes Having Cell Inhibitory Effects on Lung Cancer A549 Cells Lines

Designing new types of drugs with preferred properties against cancer is a great issue for scientists dealing with synthesis and study of biological activity. Several organometallic compounds used in chemotherapy reveal side effects. Peptides from edible sources having no side effects may play a transport role in the delivery of anticancer metal ions into targeted tumor cells. For the last two decades, peptide-metal complexes have been considered as potential anticancer agents. In this work, oxovanadium complexes of peptides from Chickpea (Cicer arietinum L.) seeds' protein hydrolysate were investigated. The albumin fraction of Chickpea seeds protein was hydrolyzed with a combination of enzymes papain, trypsin, and alcalase. The hydrolysate was combined with vanadyl ions and obtained oxovanadium complexes were studied by FTIR, SEM-EDX, and TG-DSC analyses, and cell inhibition activity against A549 cells was detected by MTT Assay. In a result, activity of the complexes (IC₅₀ = 14.39 µg/mL) increased 1.7-fold compared to the activity of inorganic salt of vanadium (IC₅₀ = 24.75 µg/mL) against A549 cells. The complexes (CPH-V) were fractionated through Sephadex G-15, and the second active fraction, named CPH-V G15-II was studied by nano-Q-TOF LC/MS. Nine peptides with a molecular mass range of 437-1864 Da were identified. Seven of them were theoretically considered as cell-penetrating peptides. These results could serve first steps for deeper fundamental research on food-derived peptide-vanadium complexes.

Exploring the Potential of Metallodrugs as Chemotherapeutics for Triple Negative Breast Cancer

This review focuses on studies of coordination and organometallic compounds as potential chemotherapeutics against triple negative breast cancer (TNBC) which has one of the poorest prognoses and worst survival rates from all breast cancer types. At present, chemotherapy is still the standard of care for TNBC since only one type of targeted therapy has been recently developed. References for metal-based compounds studied in TNBC cell lines will be listed, and those of metal-specific reviews, but a detailed overview will also be provided on compounds studied in vivo (mostly in mice models) and those compounds for which some preliminary mechanistic data was obtained (in TNBC cell lines and tumors) and/or for which bioactive ligands have been used. The main goal of this review is to highlight the most promising metal-based compounds with potential as chemotherapeutic agents in TNBC.

Vanadium Decreases Hepcidin mRNA Gene Expression in STZ-Induced Diabetic Rats, Improving the Anemic State

Diabetes is a disease with an inflammatory component that courses with an anemic state. Vanadium (V) is an antidiabetic agent that acts by stimulating insulin signaling. Hepcidin blocks the intestinal absorption of iron and the release of iron from its deposits. We aim to investigate the effect of V on hepcidin mRNA expression and its consequences on the hematological parameters in streptozotocin-induced diabetic Wistar rats. Control healthy rats, diabetic rats, and diabetic rats treated with 1 mgV/day were examined for five weeks. The mineral levels were measured in diet and serum samples. Hepcidin expression was quantified in liver samples. Inflammatory and hematological parameters were determined in serum or whole blood samples. The inflammatory status was higher in diabetic than in control rats, whereas the hematological parameters were lower in the diabetic rats than in the control rats. Hepcidin mRNA expression was significantly lower in the V-treated diabetic rats than in control and untreated diabetic rats. The inflammatory status remained at a similar level as the untreated diabetic group. However, the hematological profile improved after the V-treatment, reaching similar levels to those found in the control group. Serum iron level was higher in V-treated than in untreated diabetic rats. We conclude that V reduces gene expression of hepcidin in diabetic rats, improving the anemic state caused by diabetes.

Stability in solution and chemoprotection by octadecavanadates(IV/V) in E. coli cultures

Two mixed-valence octadecavanadates, (NH₄)₂(Me₄N)₅[V^IV₁₂V^V₆O₄₂I]·Me₄NI·5H₂O (V₁₈I) and [{K₆(OH₂)₁₂V^IV₁₁V^V₇O₄₁(PO₄)·4H₂O}_n] (V₁₈P), were synthesized and characterized by single-crystal X-ray diffraction analysis and FTIR, Raman, ⁵¹V NMR, EPR and UV/Vis/NIR spectroscopies. The chemoprotective activity of V₁₈I and V₁₈P towards the alkylating agent diethyl sulfate was assessed in E. coli cultures. The complex V₁₈I was nontoxic in concentrations up to 5.0 mmol L^-1, while V₁₈P presented moderate toxicity in the concentration range 0.10 - 10 mmol L^-1. Conversely, a ca. 35% enhancement in culture growth as compared to cells treated only with diethyl sulfate was observed upon addition of V₁₈I (0.10 to 2.5 mmol L^-1), while the combination of diethyl sulfate with V₁₈P increased the cytotoxicity presented by diethyl sulfate alone. ⁵¹V NMR and EPR speciation studies showed that V₁₈I is stable in solution, while V₁₈P suffers partial breakage to give low nuclearity oxidometalates of vanadium(V) and (IV). According to the results, the chemoprotective effect depends strongly on the direct reactivity of the polyoxidovanadates (POV) towards the alkylating agent. The reaction of diethyl sulfate with V₁₈I apparently produces a new, rearranged POV instead of poorly-reactive breakage products, while V₁₈P shows the formation and subsequent consumption of low-nuclearity species. The correlation of this chemistry with that of other mixed-valence polyoxidovanadates, [H₆V^IV₂V^V₁₂O₃₈PO₄]^5- (V₁₄) and [V^IV₈V^V₇O₃₆Cl]^6- (V₁₅), suggests a relationship between stability in solution and chemoprotective performance.

Spatiotemporal variations, sources, water quality and health risk assessment of trace elements in the Fen River

As the largest river in Shanxi Province, the Fen River is the main water source for regional economic and ecological development. Water deficiency and industrialization have led to serious water pollution in the Fen River. The major and trace elements of seasonal river waters were measured to determine the spatiotemporal variations and assess the water quality as well as its controlling factors in the Fen River. Trace elements are divided into high abundance elements (B, Ba, Li, and Mn) and low abundance elements (As, Cu, Fe, Ni, Rb, Se, U, and V). The spatial variation of trace elements is obvious, with low values upstream, intermediate values downstream, and very high values midstream. The average values of the trace elements showed different seasonal variations, with high values of As, B, Ba, Mn, and Rb in the wet season, high Cu, V, and Li values in the dry season, and minor seasonal variations of Fe, Ni, Se, and U concentrations. Principal component analysis (PCA) and correlation analysis (CA) showed natural origins of Ba, Mn, Ni, and U, anthropogenic input of As, B, Cu, Li, Rb, Se, and V. According to the results of absolute principal component sore-multivariate linear regression (APCS-MLR), the major pollution sources in the Fen River basin were related to human activities. The land use type significantly influenced the concentrations of trace elements, with high values in the cropland and low values in the forest. The water quality index (WQI) values were higher in the midstream and wet season. In comparison with other rivers in the world, the pollution of the Fen River is at a moderate level. Health risk assessment showed that As, Ba, Mn, Ni, V, and Se were the potential pollutants damaging in the Fen River, especially for children. This study highlights the importance of seasonal sample analysis and can provide vital data for water quality conservation in the Fen River basin.

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.

Evaluation of the genotoxicity, cytotoxicity and antimalarial effect of sodium metavanadate po in a Plasmodium yoelii yoelii infected murine model

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Oral administration of sodium metavanadate 10 mg/kg decreased parasitemia and increased survival in the Pyy mice model.

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Oral administration of 10 mg/kg of sodium metavanadate was neither genotoxic nor cytotoxic in the Pyy mice model.

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Sodium metavanadate is proposed as a potential antimalaric agent.

Malaria is a parasitic disease with the highest morbidity and mortality worldwide and antimalarial drug resistance has increased in last two decades. Chloroquine and artemisinin which were usedfor the treatment of malaria are also reported with resistances. Recently, some metallic compounds of ruthenium and iridium have been used as possible therapeutic agents against other parasites such as Leishmania and Trypanosoma cruzi. Organic and inorganic compounds of vanadium such as metavanadate, have been used lately because its therapeutic properties as antineoplastic and hypoglycemic agents. In this study we evaluated the genotoxicity and cytotoxicity of metavanadate per os and its working dose, as a previous step for the future use of metavanadate as anti-parasitic agent in a Plasmodium yoelii yoelii malarial lethal model. Our findings suggest that 10 mg/kg is a safe dose that decreases parasitemia and increases the survival of the Plasmodium yoelii yoelii infected mice with no evidence of genotoxicity, cytotoxicity with the dose selected.

Evaluation of the level of selected iron-related proteins/receptors in the liver of rats during separate/combined vanadium and magnesium administration

BACKGROUND

The current knowledge about the effects of vanadium (V) on iron (Fe)-related proteins and Fe homeostasis (which is regulated at the systemic, organelle, and cellular levels) is still insufficient.

OBJECTIVE

This fact and our earlier results prompted us to conduct studies with the aim to explain the mechanism of anemia accompanied by a rise in hepatic and splenic Fe deposition in rats receiving sodium metavanadate (SMV) separately and in combination with magnesium sulfate (MS).

RESULTS

We demonstrated for the first time that SMV (0.125 mg V/mL) administered to rats individually and in conjunction with MS (0.06 mg Mg/mL) for 12 weeks did not cause significant differences in the hepatic hepcidin (Hepc) and hemojuvelin (HJV) concentrations, compared to the control. In comparison with the control, there were no significant changes in the concentration of transferrin receptor 1 (TfR1) in the liver of rats treated with SMV and MS alone (in both cases only a downward trend of 14% and 15% was observed). However, a significant reduction in the hepatic TfR1 level was found in rats receiving SMV and MS simultaneously. In turn, the concentration of transferrin receptor 2 (TfR2) showed an increasing trend in the liver of rats treated with SMV and/or MS.

CONCLUSIONS

The experimental data suggest that the pathomechanism of the SMV-induced anemia is not associated with the effect of V on the concentration of Hepc in the liver, as confirmed by the unaltered hepatic HJV and TfR1 levels. Therefore, further studies are needed in order to check whether anemia that developed in the rats at the SMV administration (a) results from the inhibitory effect of V on erythropoietin (EPO) production, (b) is related to the effect of V on the induction of matriptase-2 (TMPRSS6) expression, or (c) is associated with the influence of this metal on haem synthesis.

Synthesis and Experimental-Computational Characterization of a Copper/Vanadium Compound with Potential Anticancer Activity

Cancer represents a major worldwide public health problem. While significant advances in different fronts are being made to combat the disease, the development of new metal-based drugs with cytotoxic capabilities is of high relevance. This work presents a heterobimetallic molecule comprising two moieties with a structure similar to Casiopeina II-gly. One of them has a cyclotetravanadate anion that functions as an inorganic bridge coordinating two Cu (II) atoms resulting in a hexanuclear [Cu(phen)(Gly)-µ2-V4O12-Cu(phen)(Gly)]2− complex, which is counterbalanced by two isolated [Cu(phen)(Gly)(H2O)]1+ cations. Ten water molecules arranged in two sets of five-member chains also play an essential role in the 3D supramolecular structure of the compound. The molecule was designed to provide Cu and V, two metals with proven anticancer capabilities in the same molecular structure. The compound was synthesized and characterized by elemental analysis; visible, FTIR, and Raman spectroscopies; 51V Nuclear Magnetic Resonance; cyclic voltammetry; and monocrystalline X-ray diffraction. The structural, spectroscopic, and electronic properties of the compound were calculated through the density functional theory (DFT) using the Minnesota functional M06-2X and the Def2TZVP/LANL2TZ(f) basis sets with an effective core potential (ECP) for metals. Noncovalent interactions were analyzed using a natural population analysis (NPA) and Hirshfeld surfaces. The compound upon dissociation provides two metals that can interact with important biological targets in a variety of cancer cell models.