Nickel and human health

The interplay of transition metals in ferroptosis and pyroptosis

Cell death is one of the most important mechanisms of maintaining homeostasis in our body. Ferroptosis and pyroptosis are forms of necrosis-like cell death. These cell death modalities play key roles in the pathophysiology of cancer, cardiovascular, neurological diseases, and other pathologies. Transition metals are abundant group of elements in all living organisms. This paper presents a summary of ferroptosis and pyroptosis pathways and their connection to significant transition metals, namely zinc (Zn), copper (Cu), molybdenum (Mo), lead (Pb), cobalt (Co), iron (Fe), cadmium (Cd), nickel (Ni), mercury (Hg), uranium (U), platinum (Pt), and one crucial element, selenium (Se). Authors aim to summarize the up-to-date knowledge of this topic.In this review, there are categorized and highlighted the most common patterns in the alterations of ferroptosis and pyroptosis by transition metals. Special attention is given to zinc since collected data support its dual nature of action in both ferroptosis and pyroptosis. All findings are presented together with a brief description of major biochemical pathways involving mentioned metals and are visualized in attached comprehensive figures.This work concludes that the majority of disruptions in the studied metals' homeostasis impacts cell fate, influencing both death and survival of cells in the complex system of altered pathways. Therefore, this summary opens up the space for further research.

Use of Hair as Matrix for Trace Elements Biomonitoring in Cattle and Roe Deer Sharing Pastures in Northern Italy

Intensive cattle breeding's environmental challenges are prompting shifts to extensive, pasture-based systems, influencing nutrient and pollutant uptake. PTEs are essential and non-essential elements, regularly found in the environment and organisms, and in which unbalances lead to health issues. Hair analysis, a non-invasive method, provides retrospective PTE exposure evaluation. This study aims to understand exposure and species-specific accumulation patterns of PTEs in cattle and roe deer sharing pastures in Northern Italy using the hair analysis. Aluminum, As, Cd, Cr, Ni, Pb, Cu, Mg, Fe, and Zn were quantified through the use of ICP-OES. Findings show As levels significantly higher in roe deer due to their selective feeding, while Cd and Pb levels align with other studies. Essential elements like Cu, Fe, and Zn are lower in cattle, possibly due to diet differences. Higher Cr and Ni levels in cattle suggest contamination or physiological differences in accumulation patterns. In conclusion, hair analysis is valuable for monitoring environmental PTE exposure, highlighting significant interspecies differences and the potential of both animals as bioindicators in shared grazing areas.

Small-Molecule Fluorescent Probes for Binding- and Activity-Based Sensing of Redox-Active Biological Metals

Although transition metals constitute less than 0.1% of the total mass within a human body, they have a substantial impact on fundamental biological processes across all kingdoms of life. Indeed, these nutrients play crucial roles in the physiological functions of enzymes, with the redox properties of many of these metals being essential to their activity. At the same time, imbalances in transition metal pools can be detrimental to health. Modern analytical techniques are helping to illuminate the workings of metal homeostasis at a molecular and atomic level, their spatial localization in real time, and the implications of metal dysregulation in disease pathogenesis. Fluorescence microscopy has proven to be one of the most promising non-invasive methods for studying metal pools in biological samples. The accuracy and sensitivity of bioimaging experiments are predominantly determined by the fluorescent metal-responsive sensor, highlighting the importance of rational probe design for such measurements. This review covers activity- and binding-based fluorescent metal sensors that have been applied to cellular studies. We focus on the essential redox-active metals: iron, copper, manganese, cobalt, chromium, and nickel. We aim to encourage further targeted efforts in developing innovative approaches to understanding the biological chemistry of redox-active metals.

The association between blood nickel level and handgrip strength in patients undergoing maintenance hemodialysis

BACKGROUND

Progressive loss of peripheral muscle strength is highly pronounced in patients receiving maintenance hemodialysis (MHD), of which the pathological mechanism tends to be multifactorial. Plasma nickel was reportedly correlated with muscular strength in non-dialysis patients. However, scarce is known regarding the association between blood nickel level and handgrip strength among the patients undergoing MHD.

METHODS

This cross-sectional study included patients undergoing MHD at our center in October 2021. Blood samples were collected before the hemodialysis sessions. Nickel level was measured using inductively coupled plasma mass spectrometry. Eligible patients were stratified into three groups by the blood nickel level: tertile 1 (≥ 5.2 ug/L); tertile 2 (< 5.2 ug/L and ≥ 4.5 ug/L); and tertile 3 (< 4.5 ug/L). Handgrip strength measurement was used to evaluate the muscle status. Spearman's analyses and multivariable linear regression analyses were performed to study the relationship between blood nickel level and handgrip strength.

RESULTS

A total of 236 patients were enrolled, with an average age of 55.51 ± 14.27 years and a median dialysis vintage of 83 (IQR: 48-125) months. Patients in group with a higher blood nickel level (tertile 1) tended to be female, had longer dialysis vintage and higher Kt/V, but lower BMI, serum creatinine, hemoglobin, and handgrip strength level (all p < 0.05). After adjustment for confounding factors in multivariable models, for every 1ug/L increase in nickel level, the patient's handgrip strength decreases by 2.81 kg (β: - 2.810, 95% confidence interval: - 5.036 to - 0.584, p = 0.014). Restricted cubic spline confirmed the relationship was nearly linear.

CONCLUSIONS

Our study highlighted that blood nickel level was related to handgrip strength in patients undergoing MHD. Prospective studies with larger sample sizes are still needed to confirm the result.

Nickel as a modifier of calcium oxalate: an in situ liquid cell TEM investigation of nucleation and growth

Despite extensive research on the nucleation and growth of calcium oxalate (CaOx) crystals, there are still several challenges and unknowns that remain. In particular, the role of trace metal elements in the promotion or inhibition of CaOx crystals is not well understood. In the present study, in situ graphene liquid cell transmission electron microscopy (in situ GLC TEM) was used to observe real-time, nanoscale transformations of CaOx crystals in the presence of nickel ions (Ni2+). The results showed that Ni2+ form Ni-water complexes, acting as a shape-directing species, generating a unique morphology and altering growth kinetics. Transient adsorption of Ni-water complexes resulted in a metastable phase formation of calcium oxalate trihydrate. Atomistic molecular dynamics simulations confirmed that Ni2+ acts as a weak inhibitor which slows down the CaOx crystallization, elucidating that Ni2+ impacts small-sized CaOx clusters by bringing more water into the clusters. This work highlighted the intricacies behind the effect of Ni2+ on CaOx biomineralization that were made possible to discern using in situ GLC TEM.

Associations between metal(loid) exposure with overweight and obesity and abdominal obesity in the general population: A cross-sectional study in China

Previous studies have revealed links between metal(loid)s and health problems; however, the link between metal(loid)s and obesity remains controversial. We evaluated the cross-sectional association between metal(loid) exposure in whole blood and obesity among the general population. Vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), molybdenum (Mo), cadmium (Cd), antimony (Sb), thallium (T1), and lead (Pb) were measured in 3029 subjects in Guangdong Province (China) using ICP-MS. The prevalence of overweight and obesity (OWO) and abdominal obesity (AOB) was calculated according to body mass index (BMI) and waist circumference (WC), respectively. Multivariate analysis showed that elevated blood Cu, Cd, and Pb levels were inversely associated with the risk of OWO, and these associations were confirmed by a linear dose-response relationship. Elevated blood Co concentration was associated with a decreased risk of AOB. A quantile g-computation approach showed a significantly negative mixture-effect of 13 metal(loid)s on OWO (OR: 0.96; 95% CI: 0.92, 0.99). Two metals-Ni and Mo-were inversely associated with the risk of OWO but positively associated with AOB. We cross-grouped the two obesity measurement types and found that the extremes of metal content were present in people with AOB only. In conclusion, blood Cu, Mo, Ni, Cd, and Pb were inversely associated with the risk of OWO. The presence of blood Co may be protective, while Ni and Mo exposure might increase the risk of AOB. The association between metal(loid) exposure and obesity warrants further investigation in longitudinal cohort studies.

A Comprehensive Review on Shilajit: What We Know about Its Chemical Composition

Shilajit, a natural material known for thousands of years, is primarily famous because it was the main constituent used for the mummification of bodies by dynastic Egyptians. However, for millennia, it has also been an important drug and supplement in traditional and modern medicine. A full search of Shilajit in the literature, reveals that its chemical composition is not known with certainty. That's due to the fact that surprisingly, no comprehensive chemical analysis has ever been performed to find all the chemicals and species present in it. Moreover, its source is not known; some believe that it is formed from dead plant residues or animal excrements, and some others believe it is a mineral secreted from rocks gradually. In this review article, it is tried to gather chemical property information available regarding this soft, mysterious black material to clarify what it is composed of and what formulation commercial supplements and drugs based on Shilajit may have. While there are many differences in the chemical compositions of Shilajit from various regions, it has been discovered that more than 80% of weight of Shilajit is mainly composed of humic substances and almost 20% of its weight consists of calcium, potassium, and magnesium. It also contains amino acids (mainly glycine) and proteins, fatty acids, bioactive compounds such as caffeic acid and gallic acid, and heavy metals including chromium, selenium, and cobalt.

Countenance and implication of Β-sitosterol, Β-amyrin and epiafzelechin in nickel exposed Rat: in-silico and in-vivo approach

The detrimental impact of reactive oxygen species on D.N.A. repair processes is one of the contributing factors to colon cancer. The idea that oxidative stress may be a significant etiological element for carcinogenesis is currently receiving more and more support. The goal of the current study is to evaluate the anti-inflammatory and anticancer activity of three powerful phytocompounds-sitosterol, amyrin, and epiafzelechin-alone and in various therapeutic combinations against colon cancer to identify the critical mechanisms that mitigate nickel's carcinogenic effect. To evaluate the ligand-protein interaction of four selected components against Vascular endothelial growth factor (VEGF), Matrix metalloproteinase-9 (MMP9) inhibitor and Interleukin-10 (IL-10) molecular docking approach was applied using PyRx bioinformatics tool. For in vivo analysis, hundred albino rats were included, divided into ten groups, each containing ten rats of weight 160-200 g. All the groups were injected with 1 ml/kg nickel intraperitoneally per week for three months, excluding the negative control group. Three of the ten groups were treated with β-sitosterol (100 mg/kg b wt), β-amyrin (100 mg/kg b wt), and epiafzelechin (200 mg/kg b wt), respectively, for one month. The later four groups were fed with combinatorial treatments of the three phyto compounds for one month. The last group was administered with commercial drug Nalgin (500 mg/kg b wt). The biochemical parameters Creatinine, Protein carbonyl, 8-hydroxydeoxyguanosine (8-OHdG), VEGF, MMP-9 Inhibitor, and IL-10 were estimated using ELISA kits and Glutathione (G.S.H.), Superoxide dismutase (S.O.D.), Catalase (C.A.T.) and Nitric Oxide (NO) were analyzed manually. The correlation was analyzed through Pearson's correlation matrix. All the parameters were significantly raised in the positive control group, indicating significant inflammation. At the same time, the levels of the foresaid biomarkers were decreased in the serum in all the other groups treated with the three phytocompounds in different dose patterns. However, the best recovery was observed in the group where the three active compounds were administered concomitantly. The correlation matrix indicated a significant positive correlation of IL-10 vs VEGF (r = 0.749**, p = 0.009), MMP-9 inhibitor vs SOD (r = 0.748**, p = 0.0 21). The study concluded that the three phytocompounds β-sitosterol, β-amyrin, and epiafzelechin are important anticancer agents which can target the cancerous biomarkers and might be used as a better therapeutic approach against colon cancer soon.

Fluorescent and chromogenic organic probes to detect group 10 metal ions: design strategies and sensing applications

Group 10 metals including Ni, Pd and Pt have been extensively applied in various essential aspects of human social life, material science, industrial manufactures, medicines and biology. The ionic forms of these metals are involved in several biologically important processes due to their strong binding capability towards different biomolecules. However, the mishandling or overuse of such metals has been linked to serious contamination of our ecological system, more specifically in soil and water bodies with acute consequences. Therefore, the detection of group 10 metal ions in biological as well as environmental samples is of huge significance from the human health point of view. Related to this, considerable efforts are underway to develop adequately efficient and facile methods to achieve their selective detection. Optical sensing of metal ions has gained increasing attention of researchers, particularly in the environmental and biological settings. Innovatively designed optical probes (fluorescent or colorimetric) are usually comprised of three basic components: an explicitly tailored receptor unit, a signalling unit and a clearly defined reporter unit. This review deals with the recent progress in the design and fabrication of fluorescent or colorimetric organic sensors for the detection of group 10 metal ions (Ni(II), Pd(II) and Pt(II)), with attention to the general aspects for design of such sensors.

Trace Elements Levels in Major Depressive Disorder-Evaluation of Potential Threats and Possible Therapeutic Approaches

The multifactorial etiology of major depressive disorder (MDD) includes biological, environmental, genetic, and psychological aspects. Recently, there has been an increasing interest in metallomic studies in psychiatry, aiming to evaluate the role of chosen trace elements in the MDD etiology as well as the progression of symptoms. This narrative review aims to summarize the available literature on the relationship between the concentration of chosen elements in the serum of patients with MDD and the onset and progression of this psychiatric condition. The authors reviewed PubMed, Web of Science, and Scopus databases searching for elements that had been investigated so far and further evaluated them in this paper. Ultimately, 15 elements were evaluated, namely, zinc, magnesium, selenium, iron, copper, aluminium, cadmium, lead, mercury, arsenic, calcium, manganese, chromium, nickel, and phosphorus. The association between metallomic studies and psychiatry has been developing dynamically recently. According to the results of current research, metallomics might act as a potential screening tool for patients with MDD while at the same time providing an assessment of the severity of symptoms. Either deficiencies or excessive amounts of chosen elements might be associated with the progression of depressive symptoms or even the onset of the disease among people predisposed to MDD.

Insights into enterovirus a-71 antiviral development: from natural sources to synthetic nanoparticles

Enteroviruses are pathogens responsible for several diseases, being enterovirus A71 (EVA71) the second leading cause of hand, foot, and mouth disease (HFMD), especially in Asia-Pacific countries. HFMD is mostly common in infants and children, with mild symptoms. However, the disease can result in severe nervous system disorders in children as well as in immunosuppressed adults. The virus is highly contagious, and its transmission occurs via fecal-oral, oropharyngeal secretions, and fomites. The EVA71 burdens the healthy systems and economies around the world, however, up to date, there is no antiviral approved to treat infected individuals and the existent vaccines are not available or approved to be used worldwide. In this context, an extensive literature research was conducted to describe and summarize the recent advances in natural and/or synthetic compounds with antiviral activity against EVA71. The summarized data presented here might simply encourage the future studies in EVA71 antiviral development, by encouraging further research encompassing these compounds or even the application of the techniques and technologies to improve or produce new antiviral molecules.

A State-of-the-Science Review on Metal Biomarkers

PURPOSE OF REVIEW

Biomarkers are commonly used in epidemiological studies to assess metals and metalloid exposure and estimate internal dose, as they integrate multiple sources and routes of exposure. Researchers are increasingly using multi-metal panels and innovative statistical methods to understand how exposure to real-world metal mixtures affects human health. Metals have both common and unique sources and routes of exposure, as well as biotransformation and elimination pathways. The development of multi-element analytical technology allows researchers to examine a broad spectrum of metals in their studies; however, their interpretation is complex as they can reflect different windows of exposure and several biomarkers have critical limitations. This review elaborates on more than 500 scientific publications to discuss major sources of exposure, biotransformation and elimination, and biomarkers of exposure and internal dose for 12 metals/metalloids, including 8 non-essential elements (arsenic, barium, cadmium, lead, mercury, nickel, tin, uranium) and 4 essential elements (manganese, molybdenum, selenium, and zinc) commonly used in multi-element analyses.

RECENT FINDINGS

We conclude that not all metal biomarkers are adequate measures of exposure and that understanding the metabolic biotransformation and elimination of metals is key to metal biomarker interpretation. For example, whole blood is a good biomarker of exposure to arsenic, cadmium, lead, mercury, and tin, but it is not a good indicator for barium, nickel, and uranium. For some essential metals, the interpretation of whole blood biomarkers is unclear. Urine is the most commonly used biomarker of exposure across metals but it should not be used to assess lead exposure. Essential metals such as zinc and manganese are tightly regulated by homeostatic processes; thus, elevated levels in urine may reflect body loss and metabolic processes rather than excess exposure. Total urinary arsenic may reflect exposure to both organic and inorganic arsenic, thus, arsenic speciation and adjustment for arsebonetaine are needed in populations with dietary seafood consumption. Hair and nails primarily reflect exposure to organic mercury, except in populations exposed to high levels of inorganic mercury such as in occupational and environmental settings. When selecting biomarkers, it is also critical to consider the exposure window of interest. Most populations are chronically exposed to metals in the low-to-moderate range, yet many biomarkers reflect recent exposures. Toenails are emerging biomarkers in this regard. They are reliable biomarkers of long-term exposure for arsenic, mercury, manganese, and selenium. However, more research is needed to understand the role of nails as a biomarker of exposure to other metals. Similarly, teeth are increasingly used to assess lifelong exposures to several essential and non-essential metals such as lead, including during the prenatal window. As metals epidemiology moves towards embracing a multi-metal/mixtures approach and expanding metal panels to include less commonly studied metals, it is important for researchers to have a strong knowledge base about the metal biomarkers included in their research. This review aims to aid metals researchers in their analysis planning, facilitate sound analytical decision-making, as well as appropriate understanding and interpretation of results.

Nickel Nanoparticles Induced Hepatotoxicity in Mice via Lipid-Metabolism-Dysfunction-Regulated Inflammatory Injury

Nickel nanoparticles (NiNPs) have wide applications in industry and biomedicine due to their unique characteristics. The liver is the major organ responsible for nutrient metabolism, exogenous substance detoxification and biotransformation of medicines containing nanoparticles. Hence, it is urgent to further understand the principles and potential mechanisms of hepatic effects on NiNPs administration. In this study, we explored the liver impacts in male C57/BL6 mice through intraperitoneal injection with NiNPs at doses of 10, 20 and 40 mg/kg/day for 7 and 28 days. The results showed that NiNPs treatment increased serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and induced pathological changes in liver tissues. Moreover, hepatic triglyceride (TG) content and lipid droplet deposition identified via de novo lipogenesis (DNL) progression were enhanced after NiNPs injection. Additionally, sustained NiNPs exposure induced a remarkable hepatic inflammatory response, significantly promoted endoplasmic reticulum stress (ER stress) sensors Ire1α, Perk and Atf6, and activated the occurrence of liver cell apoptosis. Overall, the research indicated that NiNPs exposure induced liver injury and disturbance of lipid metabolism. These findings revealed the public hazard from extreme exposure to NiNPs and provided new information on biological toxicity and biosafety evaluation.

Carcinogenic and human health risk assessment of children's and adults' exposure to toxic metal(oid)s from air PM10 in critical sites of the Republic of Serbia

With global urbanization and industrialization, air pollution has become an inevitable problem. Among air pollutants, toxic metals bound to particulate matter (PM) have a high hazardous potential, contributing to the development of several diseases, including various types of cancer. Due to PM pollution, Serbia is considered to be among the most polluted countries in Europe. Therefore, the objective of the study was to assess and characterize the non-carcinogenic and carcinogenic risks of children's and adults' exposure to metal(oid)s (Pb, Cd, Ni, and As) bound to PM₁₀ in five of the most polluted areas in the Republic of Serbia (Subotica, Smederevo, Bor, Valjevo, and Kraljevo). Non-carcinogenic (HQ and HI) and carcinogenic risk (CR) were calculated using USEPA methodology. Our results show that PM₁₀ concentrations exceeded the annual limit of 40 μg/m³ at four out of five monitoring sites (ranging from 44.33 to 63.25 μg/m³). Results obtained from Bor monitoring station show that safe limits were exceeded for both children and adults, indicating an unacceptable risk (> 1) obtained for inhalation exposure to the As (HQ = 6.14) and Cd (HQ = 1.17), while total HI was 7.43, which characterized the risk as unacceptable. For the same station, the CR value was 1.44E^-04 (> 1 × 10^-4). In other sites, the risks were acceptable. The characterized risk from exposure to the toxic elements via PM₁₀ in critical locations in Serbia contributes to improving air quality by requiring regulatory organs to take new actions and adopt new measures to reduce air pollution.

MTM1 displays a new function in the regulation of nickel resistance in Saccharomyces cerevisiae

Nickel (Ni) is an essential yet toxic trace element. Although a cofactor for many metalloenzymes, nickel function and metabolism is not fully explored in eukaryotes. Molecular biology and metallomic methods were utilized to explore the new physiological functions of nickel in Saccharomyces cerevisiae. Here we showed that MTM1 knockout cells displayed much stronger nickel tolerance than wild-type cells and mitochondrial accumulations of Ni and Fe of mtm1Δ cells dramatically decreased compared to wild-type cells when exposed to excess nickel. Superoxide dismutase 2 (Sod2p) activity in mtm1Δ cells was severely attenuated and restored through Ni supplementation in media or total protein. SOD2 mRNA level of mtm1Δ cells was significantly higher than that in the wild-type strain but was decreased by Ni supplementation. MTM1 knockout afforded resistance to excess nickel mediated through reactive oxygen species levels. Meanwhile, additional Ni showed no significant effect on the localization of Mtm1p. Our study reveals the MTM1 gene plays an important role in nickel homeostasis and identifies a novel function of nickel in promoting Sod2p activity in yeast cells.

Mechanism of effects of nickel or nickel compounds on intestinal mucosal barrier

As an important metal in industry, national defense, and production, nickel widely exists in nature and is also a necessary trace element for human beings and animals. Nickel deficiency will affect the growth and development of animals, the contents of related active substances, enzymes and other essential elements in vivo. However, excessive nickel or longer nickel exposure can induce excessive free radicals (reactive oxygen species and reactive nitrogen) in the body, which can lead to a variety of cell damage, apoptosis and canceration, and ultimately pose negative effects on the health of the body. Among them, the intestinal tract, as the largest interface between the body and the external environment, greatly increases the contact probability between nickel or nickel compounds and the intestinal mucosal barrier, thus, the intestinal structure and function are also more vulnerable to nickel damage, leading to a series of related diseases such as enteritis. Therefore, this paper briefly analyzed the damage mechanism of nickel or its compounds to the intestinal tract from the perspective of four intestinal mucosal barriers: mechanical barrier, immune barrier, microbial barrier and chemical barrier, we hope to make a certain theoretical contribution to the further research and the prevention and treatment of nickel related diseases.

Effects of Nickel at Environmentally Relevant Concentrations on Human Corneal Epithelial Cells: Oxidative Damage and Cellular Apoptosis

Nickel (Ni) is ubiquitous in the environment and evidence has suggested that Ni can cause ocular surface inflammation, especially in fine particulate matter and personal products. Continuous daily exposure to Ni-containing dust may adversely impact the human cornea, whereas the underlying mechanism of this phenomenon remains not fully understood. Here, human corneal epithelial cells (HCEC) were employed to analyze the toxicity of Ni via detections of cell morphology, cell viability, reactive oxygen species production, cell apoptosis rate, and apoptotic gene expression levels after exposure for 24 h to uncover the damage of Ni to the cornea. A concentration-dependent inhibition of HCECs’ viability and growth was observed. In particular, Ni at 100 μM significantly decreased cell viability to 76%, and many cells displayed an abnormal shape and even induced oxidative damage of HCEC by increasing ROS to 1.2 times, and further led to higher apoptosis (24%), evidenced by up-regulation of apoptotic genes Caspase-8, Caspase-9, NF-κB, IL-1β, and Caspase-3, posing a risk of dry eye. Our study suggested that Ni induces apoptosis of HCEC through oxidative damage. Therefore, Ni pollution should be comprehensively considered in health risks or toxic effects on the ocular surface.

The Ni(II)-Binding Activity of the Intrinsically Disordered Region of Human NDRG1, a Protein Involved in Cancer Development

Nickel exposure is associated with tumors of the respiratory tract such as lung and nasal cancers, acting through still-uncharacterized mechanisms. Understanding the molecular basis of nickel-induced carcinogenesis requires unraveling the mode and the effects of Ni(II) binding to its intracellular targets. A possible Ni(II)-binding protein and a potential focus for cancer treatment is hNDRG1, a protein induced by Ni(II) through the hypoxia response pathway, whose expression correlates with higher cancer aggressiveness and resistance to chemotherapy in lung tissue. The protein sequence contains a unique C-terminal sequence of 83 residues (hNDRG1*C), featuring a three-times-repeated decapeptide, involved in metal binding, lipid interaction and post-translational phosphorylation. In the present work, the biochemical and biophysical characterization of unmodified hNDRG1*C was performed. Bioinformatic analysis assigned it to the family of the intrinsically disordered regions and the absence of secondary and tertiary structure was experimentally proven by circular dichroism and NMR. Isothermal titration calorimetry revealed the occurrence of a Ni(II)-binding event with micromolar affinity. Detailed information on the Ni(II)-binding site and on the residues involved was obtained in an extensive NMR study, revealing an octahedral paramagnetic metal coordination that does not cause any major change of the protein backbone, which is coherent with CD analysis. hNDRG1*C was found in a monomeric form by light-scattering experiments, while the full-length hNDRG1 monomer was found in equilibrium between the dimer and tetramer, both in solution and in human cell lines. The results are the first essential step for understanding the cellular function of hNDRG1*C at the molecular level, with potential future applications to clarify its role and the role of Ni(II) in cancer development.

Air Quality Assessment by the Determination of Trace Elements in Lichens (Xanthoria calcicola) in an Industrial Area (Sicily, Italy)

This study provides data on variation in the content of metals and metalloids measured in the lichens (Xanthoria calcicola Oxner) collected in the Syracusan petrochemical complex (Sicily, Italy) which is considered one of the largest in Europe. Concentrations of eighteen trace elements measured in the lichens that were collected from 49 different points were analyzed using an inductively coupled plasma (ICP-MS) device. The concentrations of the typical elements of industrial emissions (As, Cr, Ni, and V) highlight the environmental criticality that exists in the study area. The interpretation of the data in terms of multi-element statistical analysis (FA) and enrichment factor (EFs) proved to be particularly useful in identifying several sources that contribute to the presence of trace elements in the atmospheric particulate between anthropogenic emissions and geogenic emissions. The results of this study reveal the versatility of the lichen species Xanthoria calcicola Oxner in the search for trace elements in highly anthropized environments, so the approach followed in this study can also be applied to other industrial contexts.

A comprehensive review on the sources, essentiality and toxicological profile of nickel

This review contains up-to-date knowledge and recent advancements on the essentiality, sources, and toxicological profile of nickel and its different compounds. Nickel is a recognized essential element for several important biological processes like the healthy growth of plants, animals, and soil/water microbes; though an excess amount of nickel intoxicates flora and fauna. Nickel is found to affect the photosynthetic function of higher plants; it can severely degrade soil fertility and causes many chronic diseases in humans. Due to the huge growth in the nickel industry and consumption of nickel-containing products, environmental pollution has become inevitable by the element nickel and also varieties of its by-products through all the phases of making, utilization and dumping. We have focused on the importance of agenda 2030 (UN 17 SDGs) during the preparation of the write-up and have highlighted goals 3, 6, 8, 9, 11, 12, 13, 14, and 15 by elaborately discussing associated points. The plausible molecular mechanism of nickel toxicity is presented in simple diagrams. The article elaborates on possible methods for remediation of nickel toxicity and the treatment of nickel dermatitis and nickel cancer. Recent advancements in the understanding of the dual aspects of nickel as beneficial and a carcinogen are the key subject of this article.

This review contains up-to-date knowledge and recent advancements on the essentiality, sources, and toxicological profile of nickel and its different compounds.

Comparison of the Content of Several Elements in Seawater, Sea Cucumber Eupentacta fraudatrix and Its High-Molecular-Mass Multiprotein Complex

Metal ions and other elements play many different critical roles in all biological processes. They can be especially important in high concentrations for the functioning of organisms living in seawater. It is important to understand how much the concentrations of different trace elements in such organisms can be higher than in seawater. Some marine organisms capable of rapid recovery after different injuries are fascinating in this regard. Sea cucumbers Eupentacta fraudatrix can completely restore all organs and the whole body within several weeks after their division into two parts. Here, for the first time, a comparison of the content of different elements in seawater, sea cucumber, and its very stable multiprotein complex (2000 kDa) was performed using two-jet plasma atomic emission spectrometry. Among the 18 elements we found in sea cucumbers, seawater contained only six elements in detectable amounts, and their content decreased in the following order: Mg > Ca > B > Sr ≈ Si > Cr (0.13−930 µg/g of seawater). The content of these elements in sea cucumbers was higher compared with seawater (-fold): Ca (714) > Sr (459) > Cr (75) > Si (42)> B (12) > Mg (6.9). Only four of them had a higher concentration in the protein complex than in seawater (-fold): Si (120.0) > Cr (31.5) > Ca (9.1) > Sr (8.8). The contents of Mg and B were lower in the protein complex than in seawater. The content of elements additionally found in sea cucumbers decreased in the order (µg/g of powder) of P (1100) > Fe (47) > Mn (26) > Ba (15) > Zn (13) > Al (9.3) > Mo (2.8) > Cu (1.4) > Cd (0.3), and in the protein complex, in the order of P (290) > Zn (51) > Fe (23) > Al (14) ≈ Ni (13) > Cu (7.5) > Ba (2.5) ≈ Co (2.0) ≈ Mn (1.6) > Cd (0.7) >Ag (0.2). Thus, sea cucumbers accumulate various elements, including those contained in very low concentrations in seawater. The possible biological roles of these elements are discussed here.

Comparative Study of Potentially Toxic Nickel and Their Potential Human Health Risks in Seafood (Fish and Mollusks) from Peninsular Malaysia

Human exposure to highly nickel (Ni)-polluted environments through oral ingestion pathways may cause various pathological effects. This biomonitoring study aimed to assess the human health risk of potentially toxic Ni in 19 species of marine fishes from Setiu (Terengganu) and two popular seafood molluscs (mangrove snail Cerithidea obtusa and cockle Anadara granosa) from the coastal area of Peninsular Malaysia. The Ni levels of the three seafood types were found below the maximum permissible limit for Ni. The Ni target hazard quotient values of all seafood were lower than 1.00 for average and high-level (AHL) Malaysian consumers, indicating no Ni's non-carcinogenic risk of seafood consumption. It was also found that the calculated values of estimated weekly intake were below than established provisional tolerable weekly intake of Ni for both AHL consumers. It can be concluded that both the AHL consumption of seafood would not pose adverse effects of Ni to the consumers. This study provided a scientific basis for the food safety assessment of Ni and suggestions for risk management of potentially toxic Ni of seafood consumption in Malaysia.

Chlorogenic Acid-Loaded Mesoporous Silica Nanoparticles Modified with Hexa-Histidine Peptides Reduce Skin Allergies by Capturing Nickel

Nickel-induced contact dermatitis is a severe allergic reaction to objects or environments that contain nickel. Many nanomaterials have been developed to reduce skin allergies by capturing nickel, but few agents are effective and safe. In this work, mesoporous silica nanoparticles (MSN) were synthesized and decorated with hexa-histidine peptides (denoted as MSN-His⁶), making it a strong nickel chelator. Subsequently, a dietary polyphenol, chlorogenic acid, was loaded into the mesopores of MSN (denoted as MSN-His⁶@CGA), realizing the potential of its anti-inflammatory properties. In vitro and in vivo experiments revealed that the synthesized MSN-His⁶@CGA nanoparticles exhibited more stable and stronger chelation, better biocompatibility, and ideal allergy-relieving ability, whether for environmental metal contamination or for allergic contact dermatitis caused by prolonged nickel exposure. Thus, the application of mesoporous silica-based nanoparticles may represent an ideal approach to alleviate skin allergies by capturing nickel, which would benefit people who suffer from metal-induced contact dermatitis.

Involvement of Ca2+ and ROS signals in nickel-impaired human sperm function

As one of the main environmental pollutants and occupational hazards, nickel has been reported to have mutagenic, carcinogenic, and teratogenic properties, as well as reproductive toxicity. However, how nickel affects human reproduction is still unclear. In this study, the toxicity of nickel on human sperm and the underlying mechanisms were evaluated in vitro. We found that NiCl₂ (10, 50, and 250 μM) impaired sperm total motility and progressive motility in a dose- and time-dependent manner. In addition, sperm hyperactivation and the ability of human sperm to penetrate a viscous medium were found to be compromised after nickel exposure. Mechanically, NiCl₂ significantly inhibited the basal intracellular Ca²⁺ signaling. Besides, reactive oxygen species (ROS), superoxide, and malondialdehyde levels were increased in human sperm after exposure to different concentrations of NiCl₂. Consistently, eliminating excess ROS by N-acetyl-L-cysteine or tocopherol significantly alleviated nickel-impaired sperm motility. Taken together, these results revealed that nickel could compromise sperm functions by interfering with Ca²⁺ signaling and inducing excessive oxidative stress. These findings suggest that, in the high and occupational nickel exposure environments, the contribution of nickel toxicity to the males who wish to preserve their fertility is worthy of careful evaluation.

Heavy metal ion concentration in the amniotic fluid of preterm and term pregnancies from two cities with different industrial output

The growth and development of the fetus is a complex phenomenon that can be influenced by several variables. High quantities of heavy metal ions in the amniotic fluid have been linked to poor health, especially in industrial, polluted and poor areas. The aim of the present study was to assess the differences in the concentration of these ions between preterm (weeks 15-37) and term pregnancies (starting at week 37). Another objective was to compare pregnancies from two cities with different industry levels. Two sample lots from two Romanian cities were analyzed. A total of 100 patients from Timisoara were compared with 60 from Petrosani, a heavy industry city in Romania. Demographic data were collected, and amniocentesis was performed on all women. Lead (Pb), copper (Cu), nickel (Ni), cadmium (Cd), arsenic (As), iron (Fe) and zinc (Zn) concentrations were assessed. Descriptive and analytical statistics were performed using the Mann-Whitney U test for non-parametric data and the Fisher's exact test for categorical data. In addition, categorical data was represented graphically. In the Timisoara cohort, the differences in heavy metal concentrations between preterm and term pregnancies were not statistically significant. In the Petrosani cohort, however, the concentrations of Zn (P=0.02606) and Cd (P=0.01512) were higher in preterm than in term pregnancies. When comparing the two cohorts as a whole, the concentration of Pb (P=0.04513), Cd (P=0.00002), As (P=0.03027) and Zn (P<0.00001) were higher in the patients from Petrosani than in those from Timisoara. Only Cu concentrations were higher in the Timisoara cohort (P<0.00001). The concentrations of Ni (P=0.78150) and Fe (P=0.44540) did not differ statistically. Thus, amniocentesis is an important diagnostic and exploratory tool in determining differences in the concentrations of elements such as heavy metal ions. Research over a longer period of time should be carried out to examine the relation between heavy metal ions concentration and possible postnatal health outcomes.

Nickel sulfate exposure induces ovarian inflammation and fibrosis and decreases oocyte quality in mice

Nickel is a heavy metal element extensively distributed in the environment and widely used in modern life. Divalent nickel is one of the most widespread forms of nickel and has been reported as toxic to various tissues. However, whether exposure to divalent nickel negatively affects ovarian homeostasis and oocyte quality remains unclear. In this study, we found that 3 weeks of nickel sulfate exposure affected body growth and decreased the weight and coefficient of the ovary, and increased atretic follicles exhibiting enhanced apoptosis in granulosa cells. Further studies have found that nickel sulfate triggered ovarian fibrosis and inflammation via transforming growth factor-β1 and nuclear factor-κB pathways, and reduced oocyte development ability. In addition, nickel sulfate increased the level of reactive oxygen species, which induced DNA damage and early apoptosis. Moreover, it was found that nickel sulfate caused damage to the mitochondria showing aberrant morphology, distribution and membrane potential while decreased levels of histone methylation. To summarize, our results indicated that nickel sulfate exposure triggered ovarian fibrosis and inflammation and caused structural and functional disorders of mitochondria in oocytes, which consequently disturbed ovarian homeostasis and follicle development and decreased oocyte quality.

Kinetic mechanisms by which nickel alters the calcium (Ca2+) transport in intact rat liver

In the present work, the multiple-indicator dilution (MID) technique was used to investigate the kinetic mechanisms by which nickel (Ni²⁺) affects the calcium (Ca²⁺) transport in intact rat liver. ⁴⁵Ca²⁺ and extra- and intracellular space indicators were injected in livers perfused with 1 mM Ni²⁺, and the outflow profiles were analyzed by a mathematical model. For comparative purposes, the effects of norepinephrine were measured. The influence of Ni²⁺ on the cytosolic Ca²⁺ concentration ([Ca²⁺]_c) in human hepatoma Huh7 cells and on liver glycogen catabolism, a biological response sensitive to cellular Ca²⁺, was also evaluated. The estimated transfer coefficients of ⁴⁵Ca²⁺ transport indicated two mechanisms by which Ni²⁺ increases the [Ca²⁺]_c in liver under steady-state conditions: (1) an increase in the net efflux of Ca²⁺ from intracellular Ca²⁺ stores due to a stimulus of Ca²⁺ efflux to the cytosolic space along with a diminution of Ca²⁺ re-entry into the cellular Ca²⁺ stores; (2) a decrease in Ca²⁺ efflux from the cytosolic space to vascular space, minimizing Ca²⁺ loss. Glycogen catabolism activated by Ni²⁺ was transient contrasting with the sustained activation induced by norepinephrine. Ni²⁺ caused a partial reduction in the norepinephrine-induced stimulation in the [Ca²⁺]_c in Huh7 cells. Our data revealed that the kinetic parameters of Ca²⁺ transport modified by Ni²⁺ in intact liver are similar to those modified by norepinephrine in its first minutes of action, but the membrane receptors or Ca²⁺ transporters affected by Ni²⁺ seem to be distinct from those known to be modulated by norepinephrine.

High Concentration of Heavy Metal and Metalloid Levels in Edible Campomanesia adamantium Pulp from Anthropic Areas

This study aimed to quantify the extent of heavy metal, non-metal and metalloid levels in the Campomanesia adamantium pulp obtained from an area crossed by road experiencing high large vehicle traffic and intensive agriculture modern farming, to monitor the health risks associated with pulp consumption by humans. For this purpose, in three spots located within this area, ripe fruits were collected on the roadside, bush and farm-margin. Pulp samples were digested by microwave-assisted equipment, and chemical elements were quantified by ICP OES. The concentrations of K, Pb, Se, Fe, Mo, Zn, Co, Ni and Mn in the pulp collected in roadside/bush points showed statistical differences (p < 0.05). The heavy metals and metalloid concentrations that exceeded FAO/WHO standards were ordered Pb > As > Mo > Co > Ni > Mn > Cr. Therefore, among these metalloid and heavy metals, As, Pb and Cr were found to be higher in farm-margin > roadside > bush (1.5 × 10⁻³, 1.1 × 10⁻³ and 6.2 × 10⁻⁴), respectively. Therefore, As is the most important metalloid with higher levels in farm-margin, roadside and bush (1.5 × 10⁻³, 1.0 × 10⁻³ and 6.0 × 10⁻⁴ > 10⁻⁶–10⁻⁴ and 3.33, 2.30 and 1.34 > 1), respectively, to total cancer risk and hazard quotient, if 10 g daily of pulp are consumed.

Parental Occupation and Risk of Childhood Retinoblastoma in Denmark

OBJECTIVE

Retinoblastoma is the most common primary intraocular tumor affecting children. We examine the role of parental occupational exposures and risk of retinoblastoma among offspring.

METHODS

Our population-based case-control study linked data from four nationwide Danish registries and included all cases of retinoblastoma diagnosed in Danish children (<5 y, n = 144) between 1975 and 2014. We focused on two biologically relevant time periods: 90 days preconception to conception for fathers; conception to birth for mothers. Parents were grouped into major industry headings created from Danish industry codes.

RESULTS

We observed increased risk of all retinoblastoma for children of fathers in the food and drink industry and iron and metal industry. Bilateral disease was associated with paternal work in manufacturing and land transportation.

CONCLUSION

Our results suggest that some occupational exposures may increase the risk of childhood sporadic retinoblastoma.

Nickel carcinogenesis mechanism: cell cycle dysregulation

Nickel (Ni) is a widely distributed metal in the environment and an important pollutant due to its widespread industrial applications. Ni has various toxicity in humans and experimental animals, including carcinogenicity. However, the carcinogenic effects of Ni remain troublesome. Cell cycle dysregulation may be an important carcinogenic mechanism and is also a potential molecular mechanism for Ni complexes anti-cancerous effects. Therefore, we conducted a literature review to summarize the effects of Ni on cell cycle. Up to now, there were three different reports on Ni-induced cell cycle arrest: (i) Ni can induce cell cycle arrest in G0/G1 phase, phosphorylation and degradation of IkappaB kinase-alpha (IKKα)-dependent cyclin D1 and phosphoinositide-3-kinase (PI3K)/serine-threonine kinase (Akt) pathway-mediated down-regulation of expressions of cyclin-dependent kinases 4 (CDK4) play important role in it; (ii) Ni can induce cell cycle arrest in S phase, but the molecular mechanism is not known; (iii) G2/M phase is the target of Ni toxicity, and Ni compounds cause G2/M cell cycle phase arrest by reducing cyclinB1/Cdc2 interaction through the activation of the ataxia telangiectasia mutated (ATM)-p53-p21 and ATM-checkpoint kinase inhibitor 1 (Chk1)/Chk2-cell division cycle 25 (Cdc25) pathways. Revealing the mechanisms of cell cycle dysregulation associated with Ni exposure may help in the prevention and treatment of Ni-related carcinogenicity and toxicology.

Beyond the Mind-Serum Trace Element Levels in Schizophrenic Patients: A Systematic Review

The alterations in serum trace element levels are common phenomena observed in patients with different psychiatric conditions such as schizophrenia, autism spectrum disorder, or major depressive disorder. The fluctuations in the trace element concentrations might act as potential diagnostic and prognostic biomarkers of many psychiatric and neurological disorders. This paper aimed to assess the alterations in serum trace element concentrations in patients with a diagnosed schizophrenia. The authors made a systematic review, extracting papers from the PubMed, Web of Science, and Scopus databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Among 5009 articles identified through database searching, 59 of them were assessed for eligibility. Ultimately, 33 articles were included in the qualitative synthesis. This review includes the analysis of serum levels of the following trace elements: iron, nickel, molybdenum, phosphorus, lead, chromium, antimony, uranium, magnesium, aluminum, zinc, copper, selenium, calcium, and manganese. Currently, there is no consistency regarding serum trace element levels in schizophrenic patients. Thus, it cannot be considered as a reliable prognostic or diagnostic marker of schizophrenia. However, it can be assumed that altered concentrations of those elements are crucial regarding the onset and exaggeration of either psychotic or negative symptoms or cognitive dysfunctions.

Physicochemical, in-vitro therapeutic activity and biomolecular interaction studies of Mn(II), Ni(II) and Cu(II) complexes tethered with O2N2 ligand backbone

Two major health crisis of today's world are antimicrobial drug resistance and type II diabetes. To tackle them, there is an immediate requirement for the development of new and safer drugs and the present work is one such quest for novel and efficient drug candidates. We have developed three trace metal coordination compounds tethered with a reduced salen ligand {H₂(hpdbal)₂-an} (L), namely, a manganese-salan complex, [Mn^II(H₂O)₂{(hpdbal)₂-an}] (1), a nickel-salan complex, [Ni^II{(hpdbal)₂-an}] (2) and a copper-salan complex, [Cu^II{(hpdbal)₂-an}] (3). The compounds were characterized by elemental analysis, vibrational spectroscopy, electronic spectroscopy, thermogravimetric analysis, nuclear magnetic resonance and electron-paramagnetic resonance techniques. The compounds were evaluated for antimicrobial activity against seven pathogens (Escherichia coli, Klebsiella pneumonia, Acinetobacter baumannii, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans and Cryptococcus neoformans) and antidiabetic activity by mimicking diabetic environment on the immortal human liver cancer cells, HepG2. Complexes 1 and 2 were additionally tested for their reactivity and stability in biological media mimic conditions. The nickel(II) salan complex (2) exhibited noteworthy antifungal activity against Candida albicans and the manganese(II) salan complex (1) induced increased glucose uptake by the insulin resistant cells. Both compounds were found to be stable when solution pH conditions were varied from 3 to 9. They exhibited strong affinity of binding towards a carrier protein, bovine serum albumin which was evaluated with the aid of multi-spectroscopic techniques.

Immunotoxicity of nickel: Pathological and toxicological effects

Nickel (Ni) is a widely distributed metal in the environment and an important pollutant because of its many industrial applications. With increasing incidences of Ni contamination, Ni toxicity has become a global public health concern and recent evidence suggests that Ni adversely affects the immune system. Hence, this paper reviews the literature on immune-related effects of Ni exposure, the immunotoxicological effects of Ni, and the underlying mechanism of Ni immunotoxicity. The main focus was on the effect of Ni on the development of organs of immune system, lymphocyte subpopulations, cytokines, immunoglobulins, natural killer (NK) cells, and macrophages. Moreover, Ni toxicity also induces inflammation and several studies demonstrated that Ni could induce immunotoxicity. Excessive Ni exposure can inhibit the development of immune organs by excessively inducing apoptosis and inhibiting proliferation. Furthermore, Ni can decrease T and B lymphocytes, the specific mechanism of which requires further research. The effects of Ni on immunoglobulin A (IgA), IgG, and IgM remain unknown and while Ni inhibited IgA, IgG, and IgM levels in an animal experiment, the opposite result was found in research on humans. Ni inhibits the production of cytokines in non-inflammatory responses. Cytokine levels increased in Ni-induced inflammation responses, and Ni activates inflammation through toll like (TL)4-mediated nuclear factor-κB (NF-κB) and signal transduction cascades mitogen-activated protein kinase (MAPK) pathways. Ni has been indicated to inactivate NK cells and macrophages both in vitro and in vivo. Identifying the mechanisms underlying the Ni-induced immunotoxicity may help to explain the growing risk of infections and cancers in human populations that have been exposed to Ni for a long time. Such knowledge may also help to prevent and treat Ni-related carcinogenicity and toxicology.

Associations of Heavy Metals with Metabolic Syndrome and Anthropometric Indices

Previous studies have revealed associations between heavy metals and extensive health problems. However, the association between heavy metals and metabolic problems remains poorly defined. This study aims to investigate relationships between heavy metals and metabolic syndrome (MetS), lipid accumulation product (LAP), visceral adiposity index (VAI), and anthropometric indices, including body roundness index (BRI), conicity index (CI), body adiposity index (BAI), and abdominal volume index (AVI). We conducted a health survey of people living in southern Taiwan. Six heavy metals were measured: lead (Pb) in blood and nickel (Ni), chromium (Cr), manganese (Mn), arsenic (As), and copper (Cu) in urine. A total of 2444 participants (976 men and 1468 women) were enrolled. MetS was defined according to the Adult Treatment Panel III for Asians. Multivariable analysis showed that participants with high urine Ni (log per 1 μg/L; odds ratio (OR): 1.193; 95% confidence interval (CI): 1.019 to 1.397; p = 0.028) and high urine Cu (log per 1 μg/dL; OR: 3.317; 95% CI: 2.254 to 4.883; p < 0.001) concentrations were significantly associated with MetS. There was a significant trend of a stepwise increase in blood Pb and urine Ni, As, and Cu according to the number of MetS components (from 0 to 5, a linear p ≤ 0.002 for trend). For the determinants of indices, urine Cu was positively correlated with LAP, BRI, CI, and VAI; blood Pb was positively correlated with BRI, BAI, and AVI; urine Ni was positively correlated with LAP. High urine Cu and urine Ni levels were significantly associated with MetS, and there was a significant trend for stepwise increases in blood Pb and urine Ni, As, and Cu, accompanied by an increasing number of MetS components. Furthermore, several indices were positively correlated with urine Cu, urine Ni, and blood Pb.

Chemical elements and preeclampsia - An overview of current problems, challenges and significance of recent research

OBJECTIVES

Data on the elemental status, redistribution of the elements, role of occupational exposure and dietary assessment in preeclampsia (PE) are scarce. There are many disparities in the findings of essential and non-essential elements' role in PE. In this article we overview the changes in the content of selected elements in pregnancy complicated with the disorder of complex and not fully understood etiology. We have focused on important limitations and highlighted shortcomings in research from the last ten years period.

METHODS

The Scopus and PubMed electronic databases have been searched for English-language articles published within the time interval 2008-2018, with full text available and with the key words "preeclampsia" and "chemical element" (i.e. separately: Cd, Pb, As, Ni, Mo, Co, Cr, Mn, Se, I, Fe, Sr, Cu, Zn, Mg, K and Na) appearing in the title, abstract or keywords.

RESULTS

A total of 48 publications were eligible for this overview. Surprisingly only 4% of papers considered environmental exposure, 8%- diet and 2 %- comorbid diseases. In most published papers, occupational exposure was neglected. Meta-analysis was possible for seven elements in serum (Ca, Cu, Fe, Mg, Mn, Se, Zn), and two elements (Se, Zn) in plasma. It showed negative shift for most elements, however only several were statistically significant.

CONLUSIONS

The overview of the published data on PE and chemical elements yields varied results. Some of the reasons may be the difference in not duly validated method of determination, and huge discrepancies in study designs. The lack of detailed description of studied and control population and small number of samples constitute the most common limitations of such studies. Many of them describe the use of a single analytical procedure, therefore the quality of research may be insufficient to obtain reliable results. A history of elements' status and intake before and during pregnancy is usually not examined. Dietary assessment should be done at different stages of pregnancy, and whenever possible in the periconceptional period as well. It still needs to be established whether the deficiency of certain elements or their excess may be an etiopathogenic factor and a developmental cause of PE, and if it may serve as a target of actions in the causal treatment or even prevention of the occurrence of this disease.

Metal pollution and human health risk assessment of soils and edible plants in farmlands around Enyigba lead-zinc mining site, Ebonyi State, Nigeria

This study evaluated the level of metals in edible plants, their chemical forms in the soil, and the associated health risk in Enyigba lead-zinc mining vicinity in Ebonyi State, Nigeria. Soil sample, Telfairia occidentalis and Amaranthus hybridus were collected from mining sites (Ishiagu-Enyigba and Elinwobvu-Enyigba) and non-mining site (Ekawoke-control) and analyzed using standard protocols. The results showed that a high percentage of Cd, Pb, Fe, and Zn were associated with non-residual fraction, while Cu, Cr, and Ni were bounded with residual fraction. The order of mobility and bioavailability of the metals was as follows: Pb > Cd > Fe > Zn > Cr > Ni > Cu. Geoaccumulation index (I_geo) indicated moderate to strong pollution of the mining sites with Cd Cu, Pb, and Zn. The most significant contributor to hazard index (HI) was ingestion of edible plants; followed by ingestion, dermal-contact, and then inhalation of soil particles. HI values for Cd (1.32), Cr (1.05), and Pb (1.97-2.04) for children in the sites exceeded United States Environmental Protection Agency (USEPA) safe limit (HI > 1). Total cancer risk (TCR) for adults and children via soil inhalation or soil ingestion were below USEPA safe limit (TCR < 1.0 × 10^-4). TCR for adults and children via consumption of T. occidentalis or A. hybridus exceeded USEPA safe limit (TCR > 1.0 × 10^-4). These results strongly indicated associated noncarcinogenic and carcinogenic health risk of these metals from the soil and the edible plants around Enyigba mining sites vicinity to humans especially children, this calls for concern.

Gene expression in mouse muscle over time after nickel pellet implantation

The transition metal nickel is used in a wide variety of alloys and medical devices. Nickel can cause a range of toxicities from allergy in humans to tumors when implanted in animals. Several microarray studies have examined nickel toxicity, but so far none have comprehensively profiled expression over an extended period. In this work, male mice were implanted with a single nickel pellet in the muscle of the right leg with the left leg used as a control. At 3 week intervals up to 12 months, nickel concentrations in bioflulids and microarrays of surrounding tissue were used to track gene expression patterns. Pellet biocorrosion resulted in varying levels of systemic nickel over time, with peaks of 600 μg L-1 in serum, while global gene expression was cyclical in nature with immune related genes topping the list of overexpressed genes. IPA and KEGG pathway analyses was used to attribute overall biological function to changes in gene expression levels, supported by GO enrichment analysis. IPA pathways identified sirtuin, mitochondria, and oxidative phosphorylation as top pathways, based predominantly on downregulated genes, whereas immune processes were associated with upregulated genes. Top KEGG pathways identified were lysosome, osteoclast differentiation, and phasgosome. Both pathway approaches identified common immune responses, as well as hypoxia, toll like receptor, and matrix metalloproteinases. Overall, pathway analysis identified a negative impact on energy metabolism, and a positive impact on immune function, in particular the acute phase response. Inside the cell the impacts were on mitochondria and lysosome. New pathways and genes responsive to nickel were identified from the large dataset in this study which represents the first long-term analysis of the effects of chronic nickel exposure on global gene expression.

Nickel: Human Health and Environmental Toxicology

Nickel is a transition element extensively distributed in the environment, air, water, and soil. It may derive from natural sources and anthropogenic activity. Although nickel is ubiquitous in the environment, its functional role as a trace element for animals and human beings has not been yet recognized. Environmental pollution from nickel may be due to industry, the use of liquid and solid fuels, as well as municipal and industrial waste. Nickel contact can cause a variety of side effects on human health, such as allergy, cardiovascular and kidney diseases, lung fibrosis, lung and nasal cancer. Although the molecular mechanisms of nickel-induced toxicity are not yet clear, mitochondrial dysfunctions and oxidative stress are thought to have a primary and crucial role in the toxicity of this metal. Recently, researchers, trying to characterize the capability of nickel to induce cancer, have found out that epigenetic alterations induced by nickel exposure can perturb the genome. The purpose of this review is to describe the chemical features of nickel in human beings and the mechanisms of its toxicity. Furthermore, the attention is focused on strategies to remove nickel from the environment, such as phytoremediation and phytomining.

Alteration of Metal Elements in Radiation Injury: Radiation-Induced Copper Accumulation Aggravates Intestinal Damage

Ionizing radiation causes damage to a variety of tissues, especially radiation-sensitive tissues, such as the small intestine. Radiation-induced damage is caused primarily by increased oxidative stress in the body. Studies have shown that trace metal elements play an irreplaceable role in oxidative stress in humans, which may be associated with radiation-induced tissue damage. However, the alteration and functional significance of trace metal elements in radiation-induced injury is not clear. In this study, we explored the association between radiation-induced damage and 7 trace metal elements in mouse models. We found that the concentration of zinc and copper in mice serum was decreased significantly after irradiation, whereas that of nickel, manganese, vanadium, cobalt, and stannum was not changed by inductively coupled plasma mass spectrometry. The role of copper in radiation-induced intestines was characterized in detail. The concentration of copper was increased in irradiated intestine but reduced in irradiated heart. Immunohistochemistry staining showed that copper transporter protein copper transport 1 expression was upregulated in irradiated mouse intestine, suggesting its potential involvement in radiation-induced copper accumulation. At the cellular level, the addition of CuCl2potentiated radiation-induced reactive oxygen species in intestine-derived human intestinal epithelial cell and IEC-6 cells. Moreover, the level of copper in damaged cells may be related to the severity of radiation-induced damage as evidenced by a cell viability assay. These results indicate that copper may be involved in the progression of radiation-induced tissue damage and may be a potential therapeutic target.

The concentration of potentially toxic elements (PTEs) in muscle tissue of farmed Iranian rainbow trout (Oncorhynchus mykiss), feed, and water samples collected from the west of Iran: a risk assessment study

The pollution of the environment by potentially toxic elements (PTEs) is one of the most important raised concerns. Therefore, the current investigation was devoted to measuring the concentration of lead (Pb), cadmium (Cd), elemental mercury (Hg), nickel (Ni), iron (Fe), zinc (Zn), and copper (Cu) in muscle tissue of farmed rainbow trout (n = 30) as well as their feed (n = 15) and water (n = 15) samples collected from farms (Hamadan Province, Iran) by the aid of an inductively coupled plasma atomic emission spectrometer (ICP-OES). Also, the associated risk for human and biomagnification factor (BMF) and bioconcentration factor (BCF) for PTEs in the fish muscle through feed and water were calculated. The mean concentration of Pb, Cd, Hg, Ni, Fe, Zn, and Cu in rainbow trout muscle was reported as 0.056 ± 0.040 μg g^-1 wet weight, <LOD, 0.014 ± 0.016 μg g^-1 wet weight, 0.140 ± 0.188 μg g^-1 wet weight, 1.051 ± 0.909 μg g^-1 wet weight, 0.635 ± 0.725 μg g^-1 wet weight, and 0.275 ± 0.325 μg g^-1 wet weight, respectively, while all of the samples were contaminated in the concentrations below the permitted limits by regulatory bodies such as EC, Food and Agriculture Organization (FAO), and WHO/FAO. No significant difference between the amounts of PTEs among the collected feed and water samples was noted, while the corresponded values for PTE concentrations also were lower than the allowable limits. The values of BMF and BCF for all analyzed PTEs through water and feed were lower than 1000, demonstrating that the rainbow trout muscle could not be considered as a bioaccumulative tissue for PTEs. Additionally, no health risk due to ingestions of investigated PTEs via consumption of this rainbow trout fish was noted.

Nickel Carcinogenesis Mechanism: DNA Damage

Nickel (Ni) is known to be a major carcinogenic heavy metal. Occupational and environmental exposure to Ni has been implicated in human lung and nasal cancers. Currently, the molecular mechanisms of Ni carcinogenicity remain unclear, but studies have shown that Ni-caused DNA damage is an important carcinogenic mechanism. Therefore, we conducted a literature search of DNA damage associated with Ni exposure and summarized known Ni-caused DNA damage effects. In vitro and vivo studies demonstrated that Ni can induce DNA damage through direct DNA binding and reactive oxygen species (ROS) stimulation. Ni can also repress the DNA damage repair systems, including direct reversal, nucleotide repair (NER), base excision repair (BER), mismatch repair (MMR), homologous-recombination repair (HR), and nonhomologous end-joining (NHEJ) repair pathways. The repression of DNA repair is through direct enzyme inhibition and the downregulation of DNA repair molecule expression. Up to now, the exact mechanisms of DNA damage caused by Ni and Ni compounds remain unclear. Revealing the mechanisms of DNA damage from Ni exposure may contribute to the development of preventive strategies in Ni carcinogenicity.

The bio-relevant metals of the periodic table of the elements

The bio-relevant metals (and derived compounds) of the Periodic Table of the Elements (PTE) are in the focus. The bulk elements sodium (Na), potassium (K), magnesium (Mg), and calcium (Ca) from the s-block, which are essential for all kingdoms of life, and some of their bio-activities are discussed. The trace elements of the d-block of the PTE as far as they are essential for humans (Mn, Fe, Co, Cu, Zn, Mo) are emphasized, but V, Ni, Cd, and W, which are essential only for some forms of life, are also considered. Chromium is no longer classified as being essential. From the p-block metals only the metalloid (half-metal) selenium (Se) is essential for all forms of life. Two other metalloids, silicon and arsenic, are briefly mentioned, but they have not been proven as being essential for humans. All metals of the PTE and a plethora of their compounds are used in industry and many of them are highly toxic, like lead (Pb), which is discussed as a prime example. Several metals of the PTE, that is, their ions and complexes, are employed in medicine and we discuss the role of lithium, gallium, strontium, technetium, silver, gadolinium (the only f-block element), platinum, and gold.

Structure and dynamics of Helicobacter pylori nickel-chaperone HypA: an integrated approach using NMR spectroscopy, functional assays and computational tools

Helicobacter pylori HypA (HpHypA) is a metallochaperone necessary for maturation of [Ni,Fe]-hydrogenase and urease, the enzymes required for colonization and survival of H. pylori in the gastric mucosa. HpHypA contains a structural Zn(II) site and a unique Ni(II) binding site at the N-terminus. X-ray absorption spectra suggested that the Zn(II) coordination depends on pH and on the presence of Ni(II). This study was performed to investigate the structural properties of HpHypA as a function of pH and Ni(II) binding, using NMR spectroscopy combined with DFT and molecular dynamics calculations. The solution structure of apo,Zn-HpHypA, containing Zn(II) but devoid of Ni(II), was determined using 2D, 3D and 4D NMR spectroscopy. The structure suggests that a Ni-binding and a Zn-binding domain, joined through a short linker, could undergo mutual reorientation. This flexibility has no physiological effect on acid viability or urease maturation in H. pylori. Atomistic molecular dynamics simulations suggest that Ni(II) binding is important for the conformational stability of the N-terminal helix. NMR chemical shift perturbation analysis indicates that no structural changes occur in the Zn-binding domain upon addition of Ni(II) in the pH 6.3-7.2 range. The structure of the Ni(II) binding site was probed using ¹H NMR spectroscopy experiments tailored to reveal hyperfine-shifted signals around the paramagnetic metal ion. On this basis, two possible models were derived using quantum-mechanical DFT calculations. The results provide a comprehensive picture of the Ni(II) mode to HpHypA, important to rationalize, at the molecular level, the functional interactions of this chaperone with its protein partners.

Synthesis, characterization and application of polypyrrole-cellulose nanocomposite for efficient Ni(II) removal from aqueous solution: Box-Behnken design optimization

The role of polypyrrole-cellulose (PPy-Ce) nanocomposite for the removal of Ni(II) from aqueous solution was investigated by batch experiments. The PPy-Ce nanocomposite was prepared by chemical oxidate polymerization of pyrrole monomer with cellulose. Transmission electron micrography (TEM) showed the size of the particles varied from 80 to 95 nm. The characteristic C-O, O-H, C-N and C-C vibrations in the Fourier transform infrared (FTIR) spectra indicate that the cellulose successfully integrated with the pyrrole. Influence of experimental variables such as pH, contact time, adsorbent dose and initial Ni(II) concentration were optimized using the response surface methodology (RSM) based Box-Behnken design (BBD). The optimal conditions for maximum removal of Ni(II) were pH 8, time 65 min, adsorbent dose 0.3 mg/l and Ni(II) concentration 50 mg/l. The maximum removal efficiency under optimized conditions was >94%. The results indicate that BBD could be used to optimize experimental conditions for metal removal from aqueous solution.

Targeting Helicobacter pylori urease activity and maturation: In-cell high-throughput approach for drug discovery

BACKGROUND

Helicobacter pylori is a bacterium strongly associated with gastric cancer. It thrives in the acidic environment of the gastric niche of large portions of the human population using a unique adaptive mechanism that involves the catalytic activity of the nickel-dependent enzyme urease. Targeting urease represents a key strategy for drug design and H. pylori eradication.

METHOD

Here, we describe a novel method to screen, directly in the cellular environment, urease inhibitors. A ureolytic Escherichia coli strain was engineered by cloning the entire urease operon in an expression plasmid and used to test in-cell urease inhibition with a high-throughput colorimetric assay. A two-plasmid system was further developed to evaluate the ability of small peptides to block the protein interactions that lead to urease maturation.

RESULTS

The developed assay is a robust cellular model to test, directly in the cell environment, urease inhibitors. The efficacy of a co-expressed peptide to affect the interaction between UreF and UreD, two accessory proteins necessary for urease activation, was observed. This event involves a process that occurs through folding upon binding, pointing to the importance of intrinsically disordered hot spots in protein interfaces.

CONCLUSIONS

The developed system allows the concomitant screening of a large number of drug candidates that interfere with the urease activity both at the level of the enzyme catalysis and maturation.

GENERAL SIGNIFICANCE

As inhibition of urease has the potential of being a global antibacterial strategy for a large number of infections, this work paves the way for the development of new candidates for antibacterial drugs.