Premature chromatid separation and altered proliferation of human leukocytes treated with vanadium (III) oxide

Oxidative damage and cell cycle delay induced by vanadium(III) in human peripheral blood cells

Vanadium (V) is a metal that can enter the environment through natural routes or anthropogenic activity. In the atmosphere, V is present as V oxides, among which vanadium(III) oxide (V2O3) stands out. Cytogenetic studies have shown that V2O3 is genotoxic and cytostatic and induces DNA damage; however, the molecular mechanisms leading to these effects have not been fully explored. Therefore, we treated human peripheral blood lymphocytes in vitro, evaluated the effects of V2O3 on the phases of the cell cycle and the expression of molecules that control the cell cycle and examined DNA damage and the induction of oxidative stress. The results revealed that V2O3 did not affect cell viability at the different concentrations (2, 4, 8 or 16 μg/mL) or exposure times (24 h) used. However, V2O3 affected the percentage of G1- and S-phase cells in the cell cycle, decreased the expression of mRNAs encoding related proteins (cyclin D, cyclin E, CDK2 and CDK4) and increased the expression of γH2AX and the levels of reactive oxygen species. The ability of V2O3 to cause a cell cycle delay in G1-S phase may be associated with a decrease in the mRNA and protein expression of the cyclins/CDKs and with intracellular oxidative stress, which may cause DNA double-strand damage and H2AX phosphorylation.

Cytogenetic damage by vanadium(IV) and vanadium(III) on the bone marrow of mice

Vanadium is a strategic metal that has many important industrial applications and is generated by the use of burning fossil fuels, which inevitably leads to their release into the environment, mainly in the form of oxides. The wastes generated by their use represent a major health hazard. Furthermore, it has attracted attention because several genotoxicity studies have shown that some vanadium compounds can affect DNA; among the most studied compounds is vanadium pentoxide, but studies in vivo with oxidation states IV and III are scarce and controversial. In this study, the genotoxic and cytotoxic potential of vanadium oxides was investigated in mouse bone marrow cells using structural chromosomal aberration (SCA) and mitotic index (MI) test systems. Three groups were administered vanadium(IV) tetraoxide (V2O4) intraperitoneally at 4.7, 9.4 or 18.8 mg/kg, and three groups were administered vanadium(III) trioxide (V2O3) at 4.22, 8.46 or 16.93 mg/kg body weight. The control group was treated with sterile water, and the positive control group was treated with cadmium(II) chloride (CdCl2). After 24 h, all doses of vanadium compounds increased the percentage of cells with SCA and decreased the MI. Our results demonstrated that under the present experimental conditions and doses, treatment with V2O4 and V2O3 induces chromosomal aberrations and alters cell division in the bone marrow of mice.

The Effect of Vanadium Inhalation on the Tumor Progression of Urethane-Induced Lung Adenomas in a Mice Model

Lung cancer has the highest death rates. Aerosol drug delivery has been used for other lung diseases. The use of inhaled vanadium (V) as an option for lung cancer treatment is explored. Four groups of mice were studied: (1) Saline inhalation alone, (2) Single intraperitoneal (i.p.) dose of urethane, (3) V nebulization twice a week (Wk) for 8 Wk, and (4) A single dose of urethane and V nebulization for 8 Wk. Mice were sacrificed at the end of the experiment. Number and size of tumors, PCNA (proliferating cell nuclear antigen) and TUNEL (terminal deoxynucleotidyl tranferase dUTP nick-end labeling) immunohistochemistry were evaluated and compared within groups. Results: The size and number of tumors decreased in mice exposed to V-urethane and the TUNEL increased in this group; differences in the PCNA were not observed. Conclusions: Aerosol V delivery increased apoptosis and possibly the growth arrest of the tumors with no respiratory clinical changes in the mice.

Vanadium oxides modify the expression levels of the p21, p53, and Cdc25C proteins in human lymphocytes treated in vitro

In vitro assays have demonstrated that vanadium compounds interact with biological molecules similar to protein kinases and phosphatases and have also shown that vanadium oxides decrease the proliferation of cells, including human lymphocytes; however, the mechanism, the phase in which the cell cycle is delayed and the proteins involved in this process are unknown. Therefore, we evaluated the effects of vanadium oxides (V₂ O₃ , V₂ O₄ and V₂ O₅ ) in human lymphocyte cultures (concentrations of 2, 4, 8, or 16 μg/ml) on cellular proliferation and the levels of the p53, p21 and Cdc25C proteins. After 24 h of treatment with the different concentrations of vanadium oxides, the cell cycle phases were determined by evaluating the DNA content using flow cytometry, and the levels of the p21, p53 and Cdc25C proteins were assessed by Western blot analysis. The results revealed that the DNA content remained unchanged in every phase of the cell cycle; however, only at high concentrations did protein levels increase. Although, according to previous reports, vanadium oxides induce a delay in proliferation, DNA analysis did not show this occurring in a specific cell cycle phase. Nevertheless, the increases in p53 protein levels may cause this delay.

Genotoxic properties of materials used for endoprostheses: Experimental and human data

Approximately 2 million endoprostheses are implanted annually and metal ions as well as particles are released into the body from the materials which are used. This review describes the results of studies concerning genotoxic damage caused by artificial joints. DNA damage leads to various adverse long-term health effects in humans including cancer. Experiments with mammalian cells showed that metal ions and particles from orthopedic materials cause DNA damage. Induction of chromosomal aberrations (CA) was found in several in vitro experiments and in studies with rodents with metals from orthopedic materials. Human studies focused mainly on induction of CA (7 studies). Only few investigations (4) concerned sister chromatid exchanges, oxidative DNA damage (2) and micronucleus formation (1). CA are a reliable biomarker for increased cancer risks in humans) and were increased in all studies in patients with artificial joints. No firm conclusion can be drawn at present if the effects in humans are due to oxidative stress and if dissolved metal ions or release particles play a role. Our findings indicate that patients with artificial joints may have increased cancer risks due to damage of the genetic material. Future studies should be performed to identify safe materials and to study the molecular mechanisms in detail.

Review of the nature of some geophagic materials and their potential health effects on pregnant women: some examples from Africa

The voluntary human consumption of soil known as geophagy is a global practice and deep-rooted in many African cultures. The nature of geophagic material varies widely from the types to the composition. Generally, clay and termite mound soils are the main materials consumed by geophagists. Several studies revealed that gestating women across the world consume more soil than other groups for numerous motives. These motivations are related to medicinal, cultural and nutrients supplementation. Although geophagy in pregnancy (GiP) is a universal dynamic habit, the highest prevalence has been reported in African countries such as Kenya, Ghana, Rwanda, Nigeria, Tanzania, and South Africa. Geophagy can be both beneficial and detrimental. Its health effects depend on the amount and composition of the ingested soils, which is subjective to the geology and soil formation processes. In most cases, the negative health effects concomitant with the practice of geophagy eclipse the positive effects. Therefore, knowledge about the nature of geophagic material and the health effects that might arise from their consumption is important.