New studies on the in vitro genotoxicity of sodium molybdate and their impact on the overall assessment of the genotoxicity of molybdenum substances

Long term mortality and morbidity of Italian soldiers after deployment in Iraq as related to biomarkers assessment: Results of the SIGNUM study

INTRODUCTION

The health profile of military veterans deployed in foreign operative theatres was assessed by several international studies because of potential exposure to depleted uranium and other pollutants. Here we reported results of 15-year epidemiological surveillance assessing long-term health effects in a cohort of Italian soldiers deployed in Iraq in 2004-2005 and participating in a biomonitoring campaign to identify potential genotoxic exposure to environmental xenobiotics before and after deployment (n = 981, SIGNUM cohort).

METHODS

We evaluated mortality and hospitalization risks of the SIGNUM cohort retrospectively until 2016 and 2018 respectively. A wide cohort of military personnel never deployed abroad (n = 114,260) and the general Italian population were used as control populations in risk assessment. Causes of death and diagnoses of hospitalization were derived through deterministic record linkage with official national databases of mortality and hospital discharge. Standardized Mortality Ratio (SMR) and Standardized Hospitalization Ratio (SHR) were computed adjusting according to sex, age, area of birth, and calendar year. Differential pre-post deployment in xenobiotics concentrations and early effect biomarkers (oxidative DNA alterations and micronuclei) measured in blood serum were analysed in relation to cancer hospitalization.

RESULTS

Mortality risk due to pathologies was more than halved compared to the general population (SMR = 0.41, 95% CI 0.11-1.05) and not significantly different compared to soldiers never deployed abroad (SMR = 0.69, 95% CI 0.19-1.68). Similarly overall hospitalization risk due to pathologies was decreased with respect to the general population (SHR = 0.86, 95% CI 0.80-0.92) and comparable to the control military group (SHR = 0.99, 95% CI: 0.93-1.06). For haematological cancers a decreased hospitalization risk compared to the Italian general population was observed (SHR = 0.38, 95% CI 0-0.92). No statistically significant differences emerged in the patterns of biomarkers in association with cancer hospitalization.

CONCLUSION

The study confirms the so called 'healthy warrior' effect for the SIGNUM veterans and showed no correlation between cancer occurrence and biomonitoring markers measured on field.

Application of land snail Helix lucorum for evaluation of genotoxicity of soil pollution

Application of native species as sentinels allows environmental scientists to determine real genotoxic impact of environmental pollutants. The present study aims at investigating the DNA damage in the land snail Helix lucorum as a biomarker of soil pollution. For this reason, the genotoxic impact of contaminated soil on H. lucorum, collected from different polluted areas, was investigated using the comet assay in haemocytes and digestive gland cells. An increase in DNA damage was found in the snails sampled from polluted sites compared with the reference one. Strong correlations between DNA damage in haemocytes and digestive gland cells with the level of contamination indicate pollution-induced genotoxic effects in both tissues. At the same time, the digestive gland was more sensitive towards pollutants compared with haemolymph. A direct relationship between concentrations of Cu, As and Mo in soil and the number of damaged cells for hаemolymph and digestive gland tissue was found. However, the data obtained reflect the total genotoxicity of all pollutants in the studied areas. Significant correlations between the DNA damage measured by the comet assay and metal contents in soil indicate that it is a suitable biomarker in ecotoxicological studies. Our results indicate the effectiveness of H. lucorum in biomonitoring of environmental pollution.

Pulmonary toxicity, genotoxicity, and carcinogenicity evaluation of molybdenum, lithium, and tungsten: A review

Molybdenum, lithium, and tungsten are constituents of many products, and exposure to these elements potentially occurs at work. Therefore it is important to determine at what levels they are toxic, and thus we set out to review their pulmonary toxicity, genotoxicity, and carcinogenicity. After pulmonary exposure, molybdenum and tungsten are increased in multiple tissues; data on the distribution of lithium are limited. Excretion of all three elements is both via faeces and urine. Molybdenum trioxide exerted pulmonary toxicity in a 2-year inhalation study in rats and mice with a lowest-observed-adverse-effect concentration (LOAEC) of 6.6 mg Mo/m³. Lithium chloride had a LOAEC of 1.9 mg Li/m³ after subacute inhalation in rabbits. Tungsten oxide nanoparticles resulted in a no-observed-adverse-effect concentration (NOAEC) of 5 mg/m³ after inhalation in hamsters. In another study, tungsten blue oxide had a LOAEC of 63 mg W/m³ in rats. Concerning genotoxicity, for molybdenum, the in vivo genotoxicity after inhalation remains unknown; however, there was some evidence of carcinogenicity of molybdenum trioxide. The data on the genotoxicity of lithium are equivocal, and one carcinogenicity study was negative. Tungsten seems to have a genotoxic potential, but the data on carcinogenicity are equivocal. In conclusion, for all three elements, dose descriptors for inhalation toxicity were identified, and the potential for genotoxicity and carcinogenicity was assessed.

Bioaccumulation of heavy metals in fish species of Iran: a review

Accumulation of heavy metals (HMs) in fish tissues is an important factor in monitoring the health and safety of aquatic ecosystems. Furthermore, fish are important parts of aquatic food chains and play a significant role in human health. Considering the significant role of fish in the diet of humans and their ability to transfer and biomagnify HMs, it is necessary to determine and study these contaminants in fish tissues, especially in the edible parts of the fish. In addition to the other ecological and economic services of aquatic ecosystems, water bodies, especially the Persian Gulf in the south and the Caspian Sea in the north of Iran, are the main sources of seafood for people in nearby areas, as well as people living farther away who have gained access to seafood due to the extensive trade of aquatic organisms. This study provides an overview of the health conditions of the aquatic ecosystems in Iran by monitoring HM bioaccumulation in fish species. For this purpose, we reviewed, summarized, and evaluated papers published on HM concentrations in fish species from different aquatic ecosystems, including the Persian Gulf, the Caspian Sea, wetlands, rivers, qanats, water reservoirs, lakes, and dams, with emphasis on species habitats, feeding habits, and target organs in accumulation of HMs. Generally, the highest concentrations of HMs were observed in fishes collected from the Persian Gulf, followed by species from the Caspian Sea. Species inhabiting the lower zone of the water column and carnivorous and/or omnivorous species showed the highest levels of HMs. Moreover, liver was the main accumulator organ for HMs.

A review on alloy design, biological response, and strengthening of β-titanium alloys as biomaterials

From the past few years, developments of β-Ti alloys have been the subject of active research in the medical domain. The current paper highlights significant findings in the area of β-Ti alloy design, biological responses, strengthening mechanisms, and developing low-cost implants with a high degree of biocompatibility. It is evident that an astonishing demand for developing the low modulus-high strength implants can be fulfilled by synchronizing β stabilizer content and incorporating tailored thermo-mechanical techniques. Furthermore, the biological response of the implants is as important as the physical properties that regulate healing response; hence, the optimum selection of alloying elements plays a curial role for clinical success. The paper also presents the evolution of patents in this field from the year 2010 to 2020 showing the relevant innovations that may benefit a wide range of researchers.

Assessment of acute toxicological effects of molybdenum(IV) disulfide nano- and microparticles after single intratracheal administration in rats

Despite growing applications of molybdenum(IV) sulfide (MoS₂) nano- and microparticles in their capacity as lubricants, data available on their safety are scarce. In this study the effect of MoS₂ nano- and microparticles after single intratracheal instillation in rats has been analyzed. MoS₂ suspensions were administered at the dose of 1.5 or 5 mg MoS₂/kg body weight. The analysis after 24 h and 7 days included: blood biochemical parameters, hematological parameters, bronchoalveolar lavage fluid (BALF) parameters with selected cytokines, a comet assay and histopathological examination. In the BALF cells isolated from animals exposed to both forms, numerous macrophages loaded with particles were observed. The hematological and biochemical parameters analyzed 24 h or 7 days after the exposure to both forms did not show any biologically meaningful changes. Comet assay results showed no genotoxic effect. The histopathological analysis of the lungs revealed inflammatory changes in the respiratory system of the treated animals, slightly stronger for the microsized form. The deposits of particles observed in the lung tissue up to 7 days after the instillation indicate their easy penetration through the epithelium and prolonged clearance. Concluding, no meaningful acute systemic effects were observed, however some pathological changes were noted in the lung tissue.

Molybdenum and Nickel Nanoparticles Synthesis by Laser Ablation towards the Preparation of a Hydrodesulfurization Catalyst

A clean straightforward laser ablation method in deionized (DI) water is reported for the synthesis of Molybdenum (Mo) and Nickel (Ni) nanoparticles (NPs). The structural, morphological, and optical properties of the as-synthesized nanoparticles were investigated. Particle size was estimated to be less than 10 nm, the UV–vis spectra of the samples show the formation of H2MoO4 and NiO. The XRD results for the Ni sample show the presence of two phases, cubic nickel oxide, and an fcc metallic nickel phase, indicating the possible formation of Ni/NiO compound. The nanoparticles synthesized were used as precursors in the production of a NiMo/γ-Al2O3 catalyst. The textural and structural properties, chemical composition, and catalytic performance in a hydrodesulfurization (HDS) reaction are reported. The textural and structural properties results show the lack of pore-blocking due to the small sizes and the distribution of the metallic nanoparticles on the support. Chemical composition measured by XPS shows a ratio Ni/Mo of 1.34. Therefore, possibly Ni was deposited on Mo covering part of its active area, occupying active sites of Mo, removing its effective surface and resulting in a relatively low conversion of DBT (17%). A lower Ni/Mo ratio is required to improve the model system, which could be achieved by changing parameters at the production of the nanoparticles. The model system can also be further tuned by changing the size of the nanoparticles.

Safety and efficacy of a molybdenum compound (E7) sodium molybdate dihydrate as feed additive for sheep based on a dossier submitted by Trouw Nutrition International B.V

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on safety and efficacy of sodium molybdate dihydrate for sheep, based on a dossier submitted for the re-evaluation of the additive. The additive is currently authorised in the EU for all animal species as 'Nutritional additive' - 'Compounds of trace elements'. Taking the optimal Cu:Mo ratio of 3-10, and the highest total copper level authorised in complete feeds for sheep (15 mg/kg), the FEEDAP Panel concluded that 2.5 mg total Mo/kg complete feed is safe for sheep. Considering (i) a safe intake of 0.6 mg Mo/day, (ii) the estimate average intake figure from food in Europe (generally less than 100 μg/day), (iii) the contribution of foods of animal origin to the total molybdenum intake (estimated to be up to 22 %), and (iv) that molybdenum would not accumulate in edible tissues/products of sheep fed molybdenum supplemented diets up to the upper safe level, the FEEDAP Panel concluded that the use of sodium molybdate as a additive in sheep at 2.5 mg total Mo/kg complete feed is safe for consumers. The additive under assessment feed poses no risk by inhalation to users; it is a skin and eye irritant, but it is not considered as a skin sensitiser. Sodium molybdate used up to 2.5 mg Mo/kg complete sheep feed poses no concerns for the safety for the environment. The FEEDAP Panel recognises that molybdenum does not need to be added to diets to cover the nutritional needs of molybdenum of sheep. Molybdenum supplementation in sheep feed is considered effective in order to guarantee an adequate balance with copper, when the Cu:Mo ratio in the diet is in the range 3-10.

Cytotoxicity of Iron (III), Molybdenum (III), and their Mixtures in BALB/3T3 and HepG2 Cells

INTRODUCTION

Iron and molybdenum are essential trace elements for cell metabolism. They are involved in maintaining proper functions of enzymes, cell proliferation, and metabolism of DNA.

MATERIAL AND METHODS

BALB/3T3 and HepG2 cells were incubated with iron chloride or molybdenum trioxide at concentrations from 100 to 1,400 μM. The cells were also incubated in mixtures of iron chloride at 200 μM plus molybdenum trioxide at 1,000 μM or iron chloride at 1,000 μM plus molybdenum trioxide at 200 μM. Cell viability was determined with MTT reduction, LHD release, and NRU tests.

RESULTS

A decrease in cell viability was observed after incubating both cell lines with iron chloride or molybdenum trioxide. In cells incubated with mixtures of these trace elements, a decrease in cell viability was observed, assessed by all the used assays.

CONCLUSION

Iron (III) and molybdenum (III) decrease cell viability in normal and cancer cells. A synergistic effect of the mixture of these elements was observed.

Interactions between chromium(III) and iron(III), molybdenum(III) or nickel(II): Cytotoxicity, genotoxicity and mutagenicity studies

The aim of this study was to examine the effect of chromium(III) and iron(III) and molybdenum(III) and nickel(II) and their combinations on cyto-, genotoxicity and mutagenicity in BALB/3T3 and HepG2 cells. The results obtained from cytotoxicity assays indicate that there are differences between BALB/3T3 and HepG2 cell lines in their sensitivity to chromium chloride, iron chloride, molybdenum trioxide and nickel chloride. The statistically significant increase of DNA damage of all used microelements in both cell lines was observed. The micronucleus assay performed with the use of all concentrations shows statistically significant induction of chromosomal aberrations in all tested microelements in both cell lines. Moreover, treated cells display characteristic apoptosis in comparison to control cells. In all tested microelements, the increase of number of reverse mutations was observed with and without metabolic activation. Additions of Cr(III) at 200 μM plus Fe(III) at 1000 μM showed synergistic effect in decrease of cell viability and increase of comets, micronuclei and number of revertants in both cell lines. In case of Cr(III) at 200 μM plus Mo(III) at 1000 μM, a protective effect of chromium against molybdenum at 1000 μM toxicity in both cell lines (assessed by MTT, LDH and NRU, comet, micronucleus and Ames assays) was observed. The protective effect of Cr(III) in decrease of cell viability was observed in pair of Cr(III) at 200 μM and Ni(II) at 1000 μM in BALB/3T3 and HepG2 cell lines assessed by MTT, LDH and NRU, comet, micronucleus and Ames assays.