Metal Overload Research Articles

Rapid method for screening of both calcium and magnesium chelation with comparison of 21 known metal chelators.

Chelation is the rational treatment modality in metal overload conditions, but chelators are often non-selective and can, hence, cause an imbalance in the homeostasis of physiological metals including calcium and magnesium. The aim of this study was to develop an affordable, rapid but sensitive and precise method for determining the degree of chelation of calcium and magnesium ions and to employ this method for comparison on a panel of known metal chelators. Spectrophotometric method using o-cresolphthalein complexone (o-CC) was developed and its biological relevance was confirmed in human platelets by impedance aggregometry. The lowest detectable concentration of calcium and magnesium ions by o-CC was 2.5μM and 2μM, respectively. The indicator was stable for at least 110days. Four and seven out of twenty-one chelators strongly chelated calcium and magnesium ions, respectively. Importantly, the chelation effect of clinically used chelators was not negligible. Structure-activity relationships for eight quinolin-8-ols showed improvements in chelation particularly in the cases of dihalogen substitution, and a negative linear relationship between pKa and magnesium chelation was observed. Calcium chelation led to inhibition of platelet aggregation in concentrations corresponding to the complex formation. A novel method for screening of efficacy and safety of calcium and magnesium ion chelation was developed and validated.

Copper mediated follicular atresia: Implications for granulosa cell death

3-nitropropanoic acid is a potent oxidative stress inducer that is conventionally regarded as a regulator of follicular atresia by regulating granulosa cells (GCs) death through the apoptosis pathway. There has been no research investigating the impact of copper metal overload induced Cuproptosis in ovarian GCs as a factor contributing to hindered follicular development.To elucidate whether 3-NP-induced oxidative stress plays a contributory role in promoting Cuproptosis, and discuss the role of Cuproptosis in the development of ovarian follicles.We conducted an analysis of cuproptosis occurrence in murine GCs and C57BL/6 J mice under the influence of 3-NP and 3-NP with added exogenous copper.The results revealed that 3-NP serving as a robust facilitator of exogenous copper uptake by upregulating the expression of copper transporter 1 (CTR1). In turn, culminated in the accumulation of intracellular copper within mouse granulosa cells (mGCs). Furthermore, 3-NP promoted mitochondrial permeability transition pore opening and concurrently reduced the stability of lipoic acid proteins. These actions collectively induced the oligomerization of Dihydrolipoamide S-Acetyltransferase (DLAT), ultimately leading to cuproptosis in GCs and consequent follicular atresia. Heavy metal copper and fungal decomposition product 3-NP, induce ovarian atresia via cuproptosis, modulating the reproductive performance of female animals.

Polyimidazole ligands: Copper(II) complexes and antiproliferative activity in cancer cells

The design of novel chelators for therapeutic applications has been the subject of extensive research to address various diseases. Many chelators can manipulate the levels of metal ions within cells and effectively modulate the metal excess. In some cases, chelators show significant toxicity to cells.We investigated polyimidazole ligands by potentiometry and UV–Vis spectroscopy for their ability to form copper(II) complexes. We also compared the antiproliferative activity of the polyimidazole ligands and their copper(II) complexes with polypyridine ligands in CaCo-2 (colorectal adenocarcinoma), SH-SY5Y (neuroblastoma) and K562 (chronic myelogenous leukemia) cells and normal HaCaT (keratinocyte) cells.Polyimidazole ligands are less cytotoxic than their analogous polypyridine ligands. All polyimidazole ligands, except the tetraimidazole ligand for K562 cells, did not show any significant effect on the viability of cancer and normal cells. In contrast, the cytotoxic activity of polypiridine ligands was also observed in normal cells with IC50 values similar to those of cancer cells.Tetraimidazole ligand, the only ligand active on the leukemic K562 cell line, induced caspase-dependent apoptosis and increased intracellular reactive oxygen species production with mitochondrial damage.The low cytotoxicity of the polyimidazole ligands, even if it limits their use as anticancer agents, could make them useful in other medical applications, such as in the treatment of metal overload, microbial infections, inflammation or neurodegenerative disorders.

Metabolic Derangement of Essential Transition Metals and Potential Antioxidant Therapies.

Essential transition metals have key roles in oxygen transport, neurotransmitter synthesis, nucleic acid repair, cellular structure maintenance and stability, oxidative phosphorylation, and metabolism. The balance between metal deficiency and excess is typically ensured by several extracellular and intracellular mechanisms involved in uptake, distribution, and excretion. However, provoked by either intrinsic or extrinsic factors, excess iron, zinc, copper, or manganese can lead to cellular damage upon chronic or acute exposure, frequently attributed to oxidative stress. Intracellularly, mitochondria are the organelles that require the tightest control concerning reactive oxygen species production, which inevitably leaves them to be one of the most vulnerable targets of metal toxicity. Current therapies to counteract metal overload are focused on chelators, which often cause secondary effects decreasing patients' quality of life. New therapeutic options based on synthetic or natural antioxidants have proven positive effects against metal intoxication. In this review, we briefly address the cellular metabolism of transition metals, consequences of their overload, and current therapies, followed by their potential role in inducing oxidative stress and remedies thereof.

Potential for Novel Therapeutic Uses of Alpha Lipoic Acid.

Alpha-lipoic acid (ALA) is a potent antioxidant used in the management of diabetic neuropathy due to its ability to prevent neuronal lipid peroxidation. ALA also chelates transition metals, which can be beneficial in some diseases related to metal overload. Due to its unique antioxidant properties, ALA has potential novel applications in other diseases related to oxidative stress and inflammation. This review summarizes aspects of recent clinical trials and describes the uses of ALA in managing neuropathies. The unique pharmacological actions of ALA, coupled with relatively low toxicity, have led to several trials on the potential therapeutic uses of ALA in the management of diseases associated with increased oxidative stress, inflammation, and metal overload.

High-resolution structures with bound Mn2+ and Cd2+ map the metal import pathway in an Nramp transporter.

Transporters of the Nramp (Natural resistance-associated macrophage protein) family import divalent transition metal ions into cells of most organisms. By supporting metal homeostasis, Nramps prevent diseases and disorders related to metal insufficiency or overload. Previous studies revealed that Nramps take on a LeuT fold and identified the metal-binding site. We present high-resolution structures of Deinococcus radiodurans (Dra)Nramp in three stable conformations of the transport cycle revealing that global conformational changes are supported by distinct coordination geometries of its physiological substrate, Mn2+, across conformations, and by conserved networks of polar residues lining the inner and outer gates. In addition, a high-resolution Cd2+-bound structure highlights differences in how Cd2+ and Mn2+ are coordinated by DraNramp. Complementary metal binding studies using isothermal titration calorimetry with a series of mutated DraNramp proteins indicate that the thermodynamic landscape for binding and transporting physiological metals like Mn2+ is different and more robust to perturbation than for transporting the toxic Cd2+ metal. Overall, the affinity measurements and high-resolution structural information on metal substrate binding provide a foundation for understanding the substrate selectivity of essential metal ion transporters like Nramps.

Evaluation of Toxicity Induced by Engineered CuO Nanoparticles in Freshwater Fish, Labeo rohita

With the fast development of industries relevant to nanotechnology, the inappropriate disposal of nanoproducts may initiate a new source of pollution in aquatic ecosystems, thus posing a possible danger to aquatic life. This study evaluated the eco-toxicological effects of waterborne copper oxide nanoparticles (CuO-NPs) having a 32.84nm size and rod shape on a freshwater fish, Labeo rohita. 96-h LC50 of CuO-NPs was 353.98mg/L. Two sub-lethal concentrations equivalent to 1/3rd and 1/5th LC50/96h (70.79 and 117.99 mg/L) of CuO-NPs were selected for 15, 30, and 45-day exposure tests. Bioaccumulation for the 1/3rd 96h LC50 was significantly higher compared to 1/5th of 96-h LC50 of CuO-NPs. There was a sharp decrease in the CAT activity and this decline ultimately increased the TBARS contents. The highest percentage of damaged nuclei and genetic damage index in fish erythrocytes was recorded at the highest concentration and after 45 days of treatment. The adverse effects of CuO-NPs were examined to be dose and duration dependent with increasing extent during all studied time intervals. Summarizing, exposure to sublethal concentrations of CuO-NPs is sufficient to cause alterations in ecotoxicological endpoints such as metal overload, oxidative stress and genotoxicity after chronic exposure.

Structural basis of metal import by Nramp family transporters.

Transition metal ions like Mn2+ and Fe2+ play a crucial role in various metabolic processes in all living cells. Excess or deficiency of these essential nutrients leads to diseases including cancer, anemia etc. Cellular levels of these metals are thus tightly controlled and regulated. Nramps (natural resistance-associated macrophage proteins), a class of transition metal transporters present in all domains of life, regulate the levels of these divalent metal ions within cells and prevent disorders related to metal insufficiency or overload. In humans, there exists two Nramps: Nramp2 is indispensable for Fe2+ and Mn2+ homeostasis, while Nramp1 provides resistance against intracellular pathogens by competing with the pathogen's metal transporters (including Nramp homologs) for acquisition of essential metal ions. Nramp-mediated metal ion transport typically involves co-transported protons. A few structures of Nramps are reported to date which reveal their overall LeuT-fold and provide a preliminary understanding of metal binding and proton co-transport. To better understand the metal import mechanism, we resolved high-resolution structures of Deinococcus radiodurans Nramp (DraNramp) in three conformations in both Mn2+-bound and metal-free states, providing the first molecular map of the entire Mn2+ transport cycle. The structures reveal that global conformational changes during transport are supported by distinct coordination geometries of its physiological substrate, Mn2+, across conformations and conserved networks of polar residues lining the inner and outer gates. A Cd2+-bound structure highlights differences in coordination geometry for Mn2+ and Cd2+. Binding studies using isothermal titration calorimetry along with transport and mutational analyses reveal that the thermodynamic landscape for binding and transporting physiological metals is different and more robust to perturbation than for transporting the toxic Cd2+ metal. Overall, our results lay a foundation for understanding how metal ion transporters like Nramps evolve their substrate selectivity to different ecological niches.

Unscrambling the Role of Redox-Active Biometals in Dopaminergic Neuronal Death and Promising Metal Chelation-Based Therapy for Parkinson's Disease.

Biometals are all metal ions that are essential for all living organisms. About 40% of all enzymes with known structures require biometals to function correctly. The main target of damage by biometals is the central nervous system (CNS). Biometal dysregulation (metal deficiency or overload) is related to pathological processes. Chronic occupational and environmental exposure to biometals, including iron and copper, is related to an increased risk of developing Parkinson's disease (PD). Indeed, biometals have been shown to induce a dopaminergic neuronal loss in the substantia nigra. Although the etiology of PD is still unknown, oxidative stress dysregulation, mitochondrial dysfunction, and inhibition of both the ubiquitin-proteasome system (UPS) and autophagy are related to dopaminergic neuronal death. Herein, we addressed the involvement of redox-active biometals, iron, and copper, as oxidative stress and neuronal death inducers, as well as the current metal chelation-based therapy in PD.

Manganese Stress Tolerance Depends on Yap1 and Stress-Activated MAP Kinases

Understanding which intracellular signaling pathways are activated by manganese stress is crucial to decipher how metal overload compromise cellular integrity. Here, we unveil a role for oxidative and cell wall stress signaling in the response to manganese stress in yeast. We find that the oxidative stress transcription factor Yap1 protects cells against manganese toxicity. Conversely, extracellular manganese addition causes a rapid decay in Yap1 protein levels. In addition, manganese stress activates the MAPKs Hog1 and Slt2 (Mpk1) and leads to an up-regulation of the Slt2 downstream transcription factor target Rlm1. Importantly, Yap1 and Slt2 are both required to protect cells from oxidative stress in mutants impaired in manganese detoxification. Under such circumstances, Slt2 activation is enhanced upon Yap1 depletion suggesting an interplay between different stress signaling nodes to optimize cellular stress responses and manganese tolerance.

Birth, life and death of the Arabidopsis IRT1 iron transporter: the role of close friends and foes.

IRT1 intracellular dynamics and function are finely controlled through protein-protein interactions. In plants, iron uptake from the soil is tightly regulated to allow optimal growth and development. Iron acquisition in Arabidopsis root epidermal cells requires the IRT1 transporter, which also mediates the entry of non-iron metals. In this mini-review, we describe how protein-protein interactions regulate IRT1 intracellular dynamics and IRT1-mediated metal uptake to maintain iron homeostasis. Recent interactomic data provided interesting clues on IRT1 secretion and the putative involvement of COPI- and COPII-mediated pathways. Once delivered to the plasma membrane, IRT1 can interact with other components of the iron uptake machinery to form an iron acquisition complex that likely optimizes iron entrance in root epidermal cells. Then, IRT1 may be internalized from the plasma membrane. In the past decade, IRT1 endocytosis emerged as an essential mechanism to control IRT1 subcellular localization and thus to tune iron uptake. Interestingly, IRT1 endocytosis and degradation are regulated by its non-iron metal substrates in an ubiquitin-dependent manner, which requires a set of interacting-proteins including kinases, E3 ubiquitin ligases and ESCRT complex subunits. This mechanism is essential to avoid non-iron metal overload in Arabidopsis when the iron is scarce.

Influence of zeolite on heavy metal immobilization in municipal solid waste compost contaminated soil

The application of Municipal solid waste as compost (MSWC) in agricultural fields has become one of the most common practices. Besides its benefits, it poses some harmful effects on soil, as it increases the heavy metal content in MSWC of the soil. It is necessary to find a way to reduce the bioavailability of heavy metals in MSWC before its application into the soil. This study aimed at exploring the efficiency of zeolite as an immobilizer to dwindle heavy metal bioavailability. An incubation experiment was conducted wherein the soil samples were artificially spiked with different rates of MSWC (0, 5, and 10 t ha-1). The zeolite was added to the spiked soil at 5 different levels, namely 0, 5, 10, 15, and 20 %, and their effect on bioavailable heavy metal status was observed during different incubation intervals (0, 15. 30, 60, 90, and 120 days). Results unveiled that applying 10% zeolite significantly (P<0.05) reduced the bioavailability of lead (Pb) and nickel (Ni) to Below the detectable limit (Bdl) in all soil samples. Furthermore, the organic carbon status of soil was also enriched by MSWC and 10% zeolite application. The soil pH slightly increased (7.39) with applying 10% zeolite resulting in the immobilization of heavy metals. Hence, 10% zeolite application was one of the most effective immobilizers in eliminating the bioavailability of heavy metals. Therefore, it can be concluded that mixing zeolite with MSWC before applying it to crop fields can reduce the heavy metal overload in soil. Hence, this study highlights the potential of zeolite as an effective choice in dwindling the soil's bioavailability of heavy metal content.

Tetrahydrocurcumin-Related Vascular Protection: An Overview of the Findings from Animal Disease Models.

Tetrahydrocurcumin (THC), one of the major metabolites of CUR, possesses several CUR-like pharmacological effects; however, its mechanisms of action are largely unknown. This manuscript aims to summarize the literature on the preventive role of THC on vascular dysfunction and the development of hypertension by exploring the effects of THC on hemodynamic status, aortic elasticity, and oxidative stress in vasculature in different animal models. We review the protective effects of THC against hypertension induced by heavy metals (cadmium and iron), as well as its impact on arterial stiffness and vascular remodeling. The effects of THC on angiogenesis in CaSki xenografted mice and the expression of vascular endothelial growth factor (VEGF) are well documented. On the other hand, as an anti-inflammatory and antioxidant compound, THC is involved in enhancing homocysteine-induced mitochondrial remodeling in brain endothelial cells. The experimental evidence regarding the mechanism of mitochondrial dysfunction during cerebral ischemic/reperfusion injury and the therapeutic potential of THC to alleviate mitochondrial cerebral dysmorphic dysfunction patterns is also scrutinized and explored. Overall, the studies on different animal models of disease suggest that THC can be used as a dietary supplement to protect against cardiovascular changes caused by various factors (such as heavy metal overload, oxidative stress, and carcinogenesis). Additionally, the reviewed literature data seem to confirm THC’s potential to improve mitochondrial dysfunction in cerebral vasculature during ischemic stroke through epigenetic mechanisms. We suggest that further preclinical studies should be implemented to demonstrate THC’s vascular-protective, antiangiogenic, and anti-tumorigenic effects in humans. Applying the methods used in the presently reviewed studies would be useful and will help define the doses and methods of THC administration in various disease settings.

Heavy metal accumulation in marine water: An assessment of ONGC’s blocks in Krishna-Godavari Basin, Bay of Bengal

Heavy metal pollution, in the aquatic ecosystem, has become an area of concern garnering increasing attention since the past few decades. These metals are introduced into the marine ecosystem mainly due to anthropogenic activities including offshore Oil and Gas exploration and production activities Though rich in aliphatic and aromatic hydrocarbons, crude oil also contains some trace element like vanadium, nickel, iron, aluminium, copper and some heavy metals like lead and cadmium. Poisonous or hazardous components of crude oil are mainly benzene and heavy metals which vary depending on the source of the crude oil. Elements like copper, mercury, lead, cadmium, zinc and chromium are very toxic. Except copper and zinc, others are nonessential and toxic. In fact, all metals are toxic at high concentrations. The heavy metal overload has inhibitory effects on the development of aquatic organisms such as phytoplankton, zooplankton, and fish. The metallic compounds could disturb the oxygen level and mollusc’s development, byssus formation, as well as reproductive processes. Hence, monitoring the heavy metal concentrations in sea water over a period of time is of great help in checking the pollution level and identifying the trend, which in turn will be instrumental in formulating sustainable practices. The paper mainly focuses on the study of the concentration of non-essential heavy metals in sea water around the operational areas of ONGC in western offshore area. The distribution of heavy metals in the seawater of ONGC’s exploratory blocks in Krishna-Godavari Basin, Bay of Bengal was investigated. Fifty four sea water samples collected as per OSPAR guidelines from each blocks (Vasihta G1 PML-65, Yaman PML, Godavari PML-46, DWN M-3, KG OS DW III 62, and KG DWN 98/2-1) of Krishna-Godavari Basin, Bay of Bengal and processed samples were analyzed by ICP-MS for Pb, Cr, As, and Cd. Comparison of average results in studied 6 blocks with various seawater quality guidelines is discussed to assess the present contamination. It reveals that seawater in study area are not contaminated with respect to perceived heavy metals. Generated data will assist in future for proactive measures and minimize the impact of anthropogenic sources.

Role of Manganese Forms on Black Gram (Vigna mungo) Seedling Growth

The impact of concentration of manganese (Mn2+) forms on early seedling growth and some physiological attributes of black gram (Vigna mungo L.) have been reported in the current study. An adequate amount of 22.32 μg/mL (as in control solution) of Mn2+ was found to be crucial for proper growth and it also greatly impacts the process of photosynthesis and the amount of chlorophyll in the growing seedling. Reduced growth was observed as the concentration of Mn2+ was increased from 50 ppm up to 250 ppm. Reduced growth is due to various non-enzymatic coping mechanisms invoked by the plant to ease the metal stress which has several side effects on key plant growth attributes. One such defense strategy to reduce metal overload is the production of proline that can dilute the excess metal content. Chlorophyll content with respect to the age of the seedling is also studied and it brought interesting results.

Mechanisms of Metal-Induced Mitochondrial Dysfunction in Neurological Disorders.

Metals are actively involved in multiple catalytic physiological activities. However, metal overload may result in neurotoxicity as it increases formation of reactive oxygen species (ROS) and elevates oxidative stress in the nervous system. Mitochondria are a key target of metal-induced toxicity, given their role in energy production. As the brain consumes a large amount of energy, mitochondrial dysfunction and the subsequent decrease in levels of ATP may significantly disrupt brain function, resulting in neuronal cell death and ensuing neurological disorders. Here, we address contemporary studies on metal-induced mitochondrial dysfunction and its impact on the nervous system.

Sirtuins as molecular targets, mediators, and protective agents in metal-induced toxicity.

Metal dyshomeostasis, and especially overexposure, is known to cause adverse health effects due to modulation of a variety of metabolic pathways. An increasing body of literature has demonstrated that metal exposure may affect SIRT signaling, although the existing data are insufficient. Therefore, in this review we discuss the available data (PubMed-Medline, Google Scholar) on the influence of metal overload on sirtuin (SIRT) signaling and its association with other mechanisms involved in metal-induced toxicity. The existing data demonstrate that cadmium (Cd), mercury (Hg), arsenic (As), lead (Pb), aluminium (Al), hexavalent chromium (CrVI), manganese (Mn), iron (Fe), and copper (Cu) can inhibit SIRT1 activity. In addition, an inhibitory effect of Cd, Pb, As, and Fe on SIRT3 has been demonstrated. In turn, metal-induced inhibition of SIRT was shown to affect deacetylation of target proteins including FOXO, PGC1α, p53 and NF-kB. Increased acetylation downregulates PGC1α signaling pathway, resulting in cellular altered redox status and increased susceptibility to oxidative stress, as well as decreased mitochondrial biogenesis. Lower rates of LKB1 deacetylation may be responsible for metal-induced decreases in AMPK activity and subsequent metabolic disturbances. A shift to the acetylated FOXO results in increased expression of pro-apoptotic genes which upregulates apoptosis together with increased p53 signaling. Correspondingly, decreased NF-kB deacetylation results in upregulation of target genes of proinflammatory cytokines, enzymes, and cellular adhesion molecules thus promoting inflammation. Therefore, alterations in sirtuin activity may at least partially mediate metal-induced metabolic disturbances that have been implicated in neurotoxicity, nephrotoxicity, cardiotoxicity, and other toxic effects of heavy metals.

An overview of Salmonella enterica metal homeostasis pathways during infection.

ABSTRACTNutritional immunity is a powerful strategy at the core of the battlefield between host survival and pathogen proliferation. A host can prevent pathogens from accessing biological metals such as Mg, Fe, Zn, Mn, Cu, Co or Ni, or actively intoxicate them with metal overload. While the importance of metal homeostasis for the enteric pathogen Salmonella enterica Typhimurium was demonstrated many decades ago, inconsistent results across various mouse models, diverse Salmonella genotypes, and differing infection routes challenge aspects of our understanding of this phenomenon. With expanding access to CRISPR-Cas9 for host genome manipulation, it is now pertinent to re-visit past results in the context of specific mouse models, identify gaps and incongruities in current knowledge landscape of Salmonella homeostasis, and recommend a straight path forward towards a more universal understanding of this historic host–microbe relationship.

Triapine Derivatives Act as Copper Delivery Vehicles to Induce Deadly Metal Overload in Cancer Cells

Thiosemicarbazones continue to attract the interest of researchers as potential anticancer drugs. For example, 3-aminopyridine-2-carboxaldehyde thiosemicarbazone, or triapine, is the most well-known representative of this class of compounds that has entered multiple phase I and II clinical trials. Two new triapine derivatives HL1 and HL2 were prepared by condensation reactions of 2-pyridinamidrazone and S-methylisothiosemicarbazidium chloride with 3-N-(tert-butyloxycarbonyl) amino-pyridine-2-carboxaldehyde, followed by a Boc-deprotection procedure. Subsequent reaction of HL1 and HL2 with CuCl2·2H2O in 1:1 molar ratio in methanol produced the complexes [CuII(HL1)Cl2]·H2O (1·H2O) and [CuII(HL2)Cl2] (2). The reaction of HL2 with Fe(NO3)3∙9H2O in 2:1 molar ratio in the presence of triethylamine afforded the complex [FeIII(L2)2]NO3∙0.75H2O (3∙0.75H2O), in which the isothiosemicarbazone acts as a tridentate monoanionic ligand. The crystal structures of HL1, HL2 and metal complexes 1 and 2 were determined by single crystal X-ray diffraction. The UV-Vis and EPR spectroelectrochemical measurements revealed that complexes 1 and 2 underwent irreversible reduction of Cu(II) with subsequent ligand release, while 3 showed an almost reversible electrochemical reduction in dimethyl sulfoxide (DMSO). Aqueous solution behaviour of HL1 and 1, as well as of HL2 and its complex 2, was monitored as well. Complexes 1−3 were tested against ovarian carcinoma cells, as well as noncancerous embryonic kidney cells, in comparison to respective free ligands, triapine and cisplatin. While the free ligands HL1 and HL2 were devoid of antiproliferative activity, their respective metal complexes showed remarkable antiproliferative activity in a micromolar concentration range. The activity was not related to the inhibition of ribonucleotide reductase (RNR) R2 protein, but rather to cancer cell homeostasis disturbance—leading to the disruption of cancer cell signalling.

Specific patterns of hair content of toxic metal in foreign students of the peoples’ friendship university of Russia (RUDN university)

The aim of the study was to perform a comparative analysis of hair content of toxic metal in foreign students originating from different regions.Material and methods. An examination of first-year students of the RUDN University originating from Russia, Asia, the Middle East, Africa, and Latin America was performed in the study. Assessment of hair aluminum (Al), arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb) and tin (Sn) content was undertaken using inductively-coupled plasma mass spectrometry.Results. The obtained data demonstrate that the highest levels of Al, Cd, and Pb were observed in students originating from Africa and Latin America. The most prominent mercury accumulation was detected in subjects from Latin America. In turn, hair As content in foreign students from all regions exceeded the respective Russian values by a factor of more than two. No significant group difference in hair tin content was observed. In regression models, prior habitation in Asia, Africa, and Latin America is considered as a significant predictor of elevated hair Hg content. African origin was also associated with higher Pb levels in hair. In the case of cadmium, a direct relationship between prior habitation in Latin America tended to be significant.Conclusion. The obtained data revealed increased accumulation of toxic metals, especially, Hg, Pb, and Cd in the hair of foreign first-year students originating from Africa and Latin America, that may have a significant adverse effect on health and educational performance. At the same time, further studies aimed at investigating the particular contribution of toxic metal overload to health effects in RUDN University students are required.