Cytotoxicity and genotoxicity in liver cells induced by cobalt nanoparticles and ions

Transition metals in angiogenesis - A narrative review

The aim of this paper is to offer a narrative review of the literature regarding the influence of transition metals on angiogenesis, excluding lanthanides and actinides. To our knowledge there are not any reviews up to date offering such a summary, which inclined us to write this paper. Angiogenesis describes the process of blood vessel formation, which is an essential requirement for human growth and development. When the complex interplay between pro- and antiangiogenic mediators falls out of balance, angiogenesis can quickly become harmful. As it is so fundamental, both its inhibition and enhancement take part in various diseases, making it a target for therapeutic treatments. Current methods come with limitations, therefore, novel agents are constantly being researched, with metal agents offering promising results. Various transition metals have already been investigated in-depth, with studies indicating both pro- and antiangiogenic properties, respectively. The transition metals are being applied in various formulations, such as nanoparticles, complexes, or scaffold materials. Albeit the increasing attention this field is receiving, there remain many unanswered questions, mostly regarding the molecular mechanisms behind the observed effects. Notably, approximately half of all the transition metals have not yet been investigated regarding potential angiogenic effects. Considering the promising results which have already been established, it should be of great interest to begin investigating the remaining elements whilst also further analyzing the established effects.

Systemic toxicity eliciting metal ion levels from metallic implants and orthopedic devices - A mini review

The metal/metal alloy-based implants and prostheses are in use for over a century, and the rejections, revisions, and metal particle-based toxicities were reported concurrently. Complications developed due to metal ions, metal debris, and organo-metallic particles in orthopedic patients have been a growing concern in recent years. It was reported that local and systemic toxicity caused by such released products from the implants is one of the major reasons for implant rejection and revision. Even though the description of environmental metal toxicants and safety limits for their exposure to humans were well established in the literature, an effort was not adequately performed in the case of implant-based metal toxicology. Since the metal ion concentration in serum acts as a possible indicator of the systemic toxicity, this review summarizes the reported human serum safe limits, toxic limits, and concentration range (μg/L, ppb, etc.) for mild to severe symptoms of six (cardiac, hepatic, neuro, nephron, dermal and endocrine) systemic toxicities for twelve most commonly used metallic implants. It also covers the widely used metal ion quantification techniques and systemic toxicity treatments reported.

Selenomethionine protects hematopoietic stem/progenitor cells against cobalt nanoparticles by stimulating antioxidant actions and DNA repair functions

Hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) can differentiate into all blood lineages to maintain hematopoiesis, wound healing, and immune functions. Recently, cobalt-chromium alloy casting implants have been used extensively in total hip replacements; however, cobalt nanoparticles (CoNPs) released from the alloy were toxic to HSCs and HPCs. We aimed to investigate the mechanism underlying the toxic effect of CoNPs on HSCs/HPCs and to determine the protective effect of selenomethionine (SeMet) against CoNPs in vitro and in vivo. Human and rat CD34+ HSCs/HPCs were isolated from cord blood and bone marrow, respectively. CoNPs decreased the viability of CD34+ HSCs/HPCs and increased apoptosis. SeMet attenuated the toxicity of CoNPs by enhancing the antioxidant ability of cells. The protective effect of SeMet was not completely abolished after adding H2O2 to abrogate the improvement of the antioxidant capacity by SeMet. SeMet and CoNPs stimulated ATM/ATR DNA damage response signals and inhibited cell proliferation. Unlike CoNPs, SeMet did not damage the DNA, and cell proliferation recovered after removing SeMet. SeMet inhibited the CoNP-induced upregulation of hypoxia inducible factor (HIF)-1α, thereby disrupting the inhibitory effect of HIF-1α on breast cancer type 1 susceptibility protein (BRCA1). Moreover, SeMet promoted BRCA1-mediated ubiquitination of cyclin B by upregulating UBE2K. Thus, SeMet enhanced cell cycle arrest and DNA repair post-CoNP exposure. Overall, SeMet protected CD34+ HSCs/HPCs against CoNPs by stimulating antioxidant activity and DNA repair.

A paradox: Fe2+-containing agents decreased ROS and apoptosis induced by CoNPs in vascular endothelial cells by inhibiting HIF-1α

Cobalt nanoparticles (CoNPs) released from hip joint implants are known to have a toxic effect on several organs probably through increasing reactive oxygen species (ROS). Ferrous ion (Fe²⁺) is well-known to enhance oxidative stress by catalysing the production of ROS. However, in our pilot study, we found that Fe²⁺ conversely inhibited the ROS production induced by CoNPs. To elucidate the underlying mechanism, the present study treated vascular endothelial HUVEC and HMEC-1 cells with CoNPs alone or in combination with ferrous lactate [Fe(CH₃CHOHCOO)₂], ferrous succinate [Fe(CH₂COO)₂], and ferrous chloride (FeCl₂). CoNP toxicity was evaluated by measuring cell viability, rate of apoptosis and lactose dehydrogenase (LDH) release, and intracellular ROS levels. Treatment with CoNPs decreased cell viability, LDH release, and ROS production and increased apoptosis. CoNPs increased hypoxia-inducible factor-1α (HIF-1α) protein level and mRNA levels of vascular endothelial growth factor (VEGF) and glucose transporter 1 (GLUT1) downstream of HIF-1α signalling. Silencing HIF-1α attenuated CoNP toxicity, as seen by recovery of cell viability, LDH release, and ROS levels and reduced apoptosis. CoNPs caused a pronounced reduction of Fe²⁺ in cells, but supplementation with Fe(CH₃CHOHCOO)₂, Fe(CH₂COO)₂, and FeCl₂ restored Fe²⁺ levels and inhibited HIF-1α activation. Moreover, all three Fe²⁺-containing agents conferred protection from CoNPs; Fe(CH₃CHOHCOO)₂ and Fe(CH₂COO)₂ more effectively than FeCl₂. In summary, the present study revealed that CoNPs exert their toxicity on human vascular endothelial cells by depleting intracellular Fe²⁺ level, which causes activation of HIF-1α signalling. Supplements of Fe²⁺, especially in the form of Fe(CH3CHOHCOO)₂ and Fe(CH₂COO)₂, mitigated CoNP toxicity.

Perinatal and early-life cobalt exposure impairs essential metal metabolism in immature ICR mice

The objective of the present study was to assess the impact of cobalt (Co) exposure on tissue distribution of iron (Fe), copper (Cu), manganese (Mn), and zinc (Zn), as well as serum hepcidin levels in immature mice (18, 25, 30 days). Pregnant mice were exposed to 75 mg/kg b.w. cobalt chloride (CoCl₂ × 6H2O) with drinking water starting from 3 days before delivery and during lactation. At weaning (day 25) the offspring were separated and housed in individual cages with subsequent exposure to 75 mg/kg b.w. CoCl₂ until 30 days postnatally. Evaluation of tissue metal levels was performed by an inductively coupled plasma-mass spectrometry (ICP-MS). Serum hepcidin level was assayed by enzyme linked immunosorbent assay (ELISA). Cobalt exposure resulted in a time- and tissue-dependent increase in Co levels in kidney, spleen, liver, muscle, erythrocytes, and serum on days 18, 25, and 30. In parallel with increasing Co levels, CoCl₂ exposure resulted in a significant accumulation of Cu, Fe, Mn, and Zn in the studied tissues, with the effect being most pronounced in 25-day-old mice. Cobalt exposure significantly increased serum hepcidin levels only in day18 mice. The obtained data demonstrate that Co exposure may alter essential metal metabolism in vivo.

Alpha lipoic acid antagonizes cytotoxicity of cobalt nanoparticles by inhibiting ferroptosis-like cell death

As a main element in the hard metal industry, cobalt is one of the major components of human metal implants. Cobalt-containing implants, especially joint prostheses used for artificial joint replacement, can be corroded due to the complex physiological environment in vivo, producing a large number of nanoscale cobalt particles (Cobalt Nanoparticles, CoNPs). These CoNPs can be first accumulated around the implant to cause adverse local reactions and then enter into the blood vessels followed by reaching the liver, heart, brain, kidney, and other organs through systematic circulation, which leads to multi-system toxicity symptoms. To ensure the long-term existence of cobalt-containing implants in the body, it is urgently required to find out a safe and effective detoxification drug. Herein, we have demonstrated that CoNPs could induce the ferroptosis-like cell death through the enhancement of intracellular reactive oxygen species (ROS) level, cytoplasmic Fe²⁺ level, lipid peroxidation, and consumption of reduced glutathione (GSH) as well as inhibition of glutathione peroxidase 4 (GPX4) activity. Importantly, α-lipoic acid (ALA), a natural antioxidant with the capability to scavenge free radicals and chelate toxic metals, was found to efficiently alleviate the adverse effects of CoNPs. The present study illustrates a new mechanism of CoNPs mediated by ferroptosis-like cytotoxicity and discloses an effective method for the detoxification of CoNPs by employing the natural antioxidant of ALA, providing a basis for further in vivo detoxification study.

In vitro effects of cobalt nanoparticles on aspartate aminotransferase and alanine aminotransferase activities of wistar rats

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The effect of Co-NPs was evaluated for biochemical enzymatic toxicity.

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Aspartate aminotransferase (ASAT) and Alanine aminotransferase (ALAT) enzymes in serum, liver, and kidney of rats were used.

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The levels of enzymes were increased significantly after being exposed to Co-NPs.

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The elevated level of these enzymes can be useful in the diagnosis of any toxic injury.

Cobalt nanoparticles (Co-NPs) have been extensively used in clinical practices and medical diagnosis. In this study, the potential toxicity effects of Co-NPs with special emphasis over the biochemical enzyme activities, such as aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) in serum, liver, and kidney of Wistar rats were investigated. This toxicity measurement of nanomaterials can support the toxicological data. The biochemical enzymatic variations are powerful tools for the assessment of toxicity. ASAT and ALAT enzymes have been widely used to predict tissue-specific toxicities associated with xenobiotic. The biochemical changes induced by Co-NPs have significance in their toxicological studies because the alterations in biochemical parameters before clinical symptoms indicate either their toxicant safety or detrimental effect. Herein, Co-NPs with particle size <50 nm significantly activated ASAT and ALAT enzymes in the serum, liver, and kidney of rats at concentration-dependent order.

MTH1 is involved in the toxic and carcinogenic long-term effects induced by zinc oxide and cobalt nanoparticles

The nanoparticles (NPs) exposure-related oxidative stress is considered among the main causes of the toxic effects induced by these materials. However, the importance of this mechanism has been mostly explored at short term. Previous experience with cells chronically exposed to ZnO and Co NPs hinted to the existence of an adaptative mechanism contributing to the development of oncogenic features. MTH1 is a well-described enzyme expressed exclusively in cancer cells and required to avoid the detrimental consequences of its high prooxidant microenvironment. In the present work, a significantly marked overexpression was found when MTH1 levels were monitored in long-term ZnO and Co NP-exposed cells, a fact that correlates with acquired 2.5-fold and 3.75-fold resistance to the ZnO and Co NPs treatment, respectively. The forced stable inhibition of Mth1 expression by shRNA, followed by 6 additional weeks of exposure, significantly reduced this acquired resistance and sensitized cells to the oxidizing agents H₂O₂ and KBrO₃. When the oncogenic phenotype of Mth1 knock-down cells was evaluated, we found a decrease in several oncogenic markers, including proliferation, anchorage-independent cell growth, and migration and invasion potential. Thus, MTH1 elicits here as a relevant player in the NPs-induced toxicity and carcinogenicity. This study is the first to give a mechanistic explanation for long-term NPs exposure-derived effects. We propose MTH1 as a candidate biomarker to unravel NPs potential genotoxic and carcinogenic effects, as its expression is expected to be elevated only under exposure conditions able to induce DNA damage and the acquisition of an oncogenic phenotype.

Influence of nanoparticles on liver tissue and hepatic functions: A review

Due to the increasing interest in nanotechnology in very large application fields, including biotechnology, electronics and food industries, humans are increasingly exposed to nanoparticles (NPs). Consequently, the question about the safety of these nanomaterials and their impact on human health is a legitimate concern. The liver is the primary organ of detoxification and is one of the tissues that is most exposed to NPs. When they reach the bloodstream, NPs are mainly internalized by liver cells. This review focuses on recent in vitro and in vivo studies addressing the effects of organic and inorganic NPs on the liver. Specifically, the impact of the NPs on hepatic enzyme activities, the inflammatory response and genotoxicity processes will be described. Depending on the physicochemical parameters of the NPs and the conditions of exposure, NPs could lead to global liver injury.

Redox interactions and genotoxicity of metal-based nanoparticles: A comprehensive review

Nanotechnology is a growing science that may provide several new applications for medicine, food preservation, diagnostic technologies, and sanitation. Despite its beneficial applications, there are several questions related to the safety of nanomaterials for human use. The development of nanotechnology is associated with some concerns because of the increased risk of carcinogenesis following exposure to nanomaterials. The increased levels of reactive oxygen species (ROS) that are due to exposure to nanoparticles (NPs) are primarily responsible for the genotoxicity of metal NPs. Not all, but most metal NPs are able to directly produce free radicals through the release of metal ions and through interactions with water molecules. Furthermore, the increased production of free radicals and the cell death caused by metal NPs can stimulate reduction/oxidation (redox) reactions, leading to the continuous endogenous production of ROS in a positive feedback loop. The overexpression of inflammatory mediators, such as NF-kB and STATs, the mitochondrial malfunction and the increased intracellular calcium levels mediate the chronic oxidative stress that occurs after exposure to metal NPs. In this paper, we review the genotoxicity of different types of metal NPs and the redox mechanisms that amplify the toxicity of these NPs.

In vitro evaluation of the antitumor effect of bismuth lipophilic nanoparticles (BisBAL NPs) on breast cancer cells

Aim

The objective of this study was to evaluate the antitumor activity of lipophilic bismuth nanoparticles (BisBAL NPs) on breast cancer cells.

Materials and methods

The effect of varying concentrations of BisBAL NPs was evaluated on human MCF-7 breast cancer cells and on MCF-10A fibrocystic mammary epitheliocytes as noncancer control cells. Cell viability was evaluated with the MTT assay, plasma membrane integrity was analyzed with the calcein AM assay, genotoxicity with the comet assay, and apoptosis with the Annexin V/7-AAD assay.

Results

BisBAL NPs were spherical in shape (average diameter, 28 nm) and agglomerated into dense electronic clusters. BisBAL NP induced a dose-dependent growth inhibition. Most importantly, growth inhibition was higher for MCF-7 cells than for MCF-10A cells. At 1 µM BisBAL NP, MCF-7 growth inhibition was 51%, while it was 11% for MCF-10A; at 25 µM BisBAL NP, the growth inhibition was 81% for MCF-7 and 24% for MCF-10A. With respect to mechanisms of action, a 24-hour exposure of 10 and 100 µM BisBAL NP caused loss of cell membrane integrity and fragmentation of tumor cell DNA. BisBAL NPs at 10 µM were genotoxic to and caused apoptosis of breast cancer cells.

Conclusion

BisBAL NP-induced growth inhibition is dose dependent, and breast cancer cells are more vulnerable than noncancer breast cells. The mechanism of action of BisBAL NPs may include loss of plasma membrane integrity and a genotoxic effect on the genomic DNA of breast cancer cells.

Ionic cobalt but not metal particles induces ROS generation in immune cells in vitro

Total joint replacement is one of the most successful procedures in orthopedic surgery today. However, metal implant materials undergo wear and corrosion processes. Generated particles and ions can cause a variety of cellular reactions. Cobalt-containing alloys are used frequently in implant materials. Some studies suggest that cobalt exhibits potential cytotoxic effects, for example, via generation of reactive oxygen species (ROS). To further elucidate the effects of cobalt on human cells, we determined cell viability and cytosolic and mitochondrial superoxide formation after incubation of either ions or particles with different cells. MM-6 and Jurkat cell lines were treated for 24, 48 and 72 h with either CoCrMo particles or cobalt ions (supplied as CoCl₂ ). A total of 24 h exposure of both forms of cobalt did not induce cell death using terminal deoxynucleotidyl transferase (TUNEL) and trypan blue assay. Interestingly, the formation of superoxide (O₂ ^.- ) is evoked mainly by ionic CoCl₂ but not cobalt particles. Cobalt alloy particles are likely to even suppress O₂ ^.- formation in mitochondria in both used cell lines. Furthermore, we did not observe any effect of cobalt particles on O₂ ^.- formation in peripheral blood mononuclear cells (PBMCs) from healthy donors. We also found that the O₂ ^- formation by CoCl₂ within mitochondria is a generalized effect for all cell types used, while the formation of superoxide in cytosolic compartment is cell-type dependent. In summary, our data suggest that cobalt ions specifically induce the formation of O₂ ^.- , whereas the cobalt particles were better tolerated. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1246-1253, 2019.

Toxicological Profiling of Metal Oxide Nanoparticles in Liver Context Reveals Pyroptosis in Kupffer Cells and Macrophages versus Apoptosis in Hepatocytes

The liver and the mononuclear phagocyte system are a frequent target for engineered nanomaterials, either as a result of particle uptake and spread from primary exposure sites or systemic administration of therapeutic and imaging nanoparticles. In this study, we performed a comparative analysis of the toxicological impact of 29 metal oxide nanoparticles (NPs), some commonly used in consumer products, in transformed or primary Kupffer cells (KCs) and hepatocytes. We not only observed differences between KCs and hepatocytes, but also differences in the toxicological profiles of transition-metal oxides (TMOs, e. g., Co₃O₄) versus rare-earth oxide (REO) NPs ( e. g., Gd₂O₃). While pro-oxidative TMOs induced the activation of caspases 3 and 7, resulting in apoptotic cell death in both cell types, REOs induced lysosomal damage, NLRP3 inflammasome activation, caspase 1 activation, and pyroptosis in KCs. Pyroptosis was accompanied by cell swelling, membrane blebbing, IL-1β release, and increased membrane permeability, which could be reversed by knockdown of the pore forming protein, gasdermin D. Though similar features were not seen in hepatocytes, the investigation of the cytotoxic effects of REO NPs could also be seen to affect macrophage cell lines such as J774A.1 and RAW 264.7 cells as well as bone marrow-derived macrophages. These phagocytic cell types also demonstrated features of pyroptosis and increased IL-1β production. Collectively, these findings demonstrate important mechanistic considerations that can be used for safety evaluation of metal oxides, including commercial products that are developed from these materials.