The effect of copper nanoparticles and copper (II) salt on redox reactions and epigenetic changes in a rat model

Copper Materials for Caries Management: A Scoping Review

This study comprehensively reviewed the types, properties and potential applications of copper materials for caries management. Two researchers independently searched English publications using PubMed, Scopus and Web of Science. They screened the titles and abstracts of publications presenting original studies for review. They included 34 publications on copper materials, which were categorized as copper and copper alloy materials (13/34, 38%), copper salt materials (13/34, 38%) and copper oxide materials (8/34, 24%). All reported copper materials inhibited the growth of cariogenic bacteria such as Streptococcus mutans and Candida albicans. The materials could be doped into topical agents, restorative fillers, dental adhesives, drinking water, dental implants, orthodontic appliances, mouthwash and sugar. Most publications (29/34, 83%) were laboratory studies, five (5/34, 14%) were animal studies and only one paper (1/34, 3%) was clinical research. In conclusion, copper and copper alloy materials, copper salt materials and copper oxide materials have an antimicrobial property that inhibits cariogenic bacteria and Candida albicans. These copper materials may be incorporated into dental materials and even drinking water and sugar for caries prevention. Most publications are laboratory studies. Further clinical studies are essential to validate the effectiveness of copper materials in caries prevention.

Association between Cu/Zn/Iron/Ca/Mg levels and cerebral palsy: a pooled-analysis

It was well documented that macro/trace elements were associated with the neurodevelopment. We aimed to investigate the relationship between copper (Cu)/zinc (Zn)/iron/calcium (Ca)/magnesium (Mg) levels and cerebral palsy (CP) by performing a meta-analysis. We searched the PubMed, Embase, Cochrane and Chinese WanFang databases from January 1985 to June 2022 to yield studies that met our predefined criteria. Standard mean differences (SMDs) of Cu/Zn/Iron/Ca/Mg levels between CP cases and healthy controls were calculated using the fixed-effects model or the random-effects model, in the presence of heterogeneity. 95% confidence intervals (CI) were also computed. Sensitivity analysis was performed by omitting each study in turn. A total of 19 studies were involved in our investigation. CP cases showed markedly lower Cu, Zn, iron and Ca levels than those in controls among overall populations (SMD =  - 2.156, 95% CI - 3.013 to - 1.299, P < 10-4; SMD =  - 2.223, 95% CI - 2.966 to - 1.480, P < 10-4; SMD =  - 1.092, 95% CI - 1.513 to - 0.672, P < 10-4; SMD =  - 0.757, 95% CI - 1.475 to - 0.040, P = 0.038) and Asians (SMD =  - 2.893, 95% CI - 3.977 to - 1.809, P < 10-4; SMD =  - 2.559, 95% CI - 3.436 to - 1.683, P < 10-4; SMD =  - 1.336, 95% CI - 1.807 to - 0.865, P < 10-4; SMD =  - 1.000, 95% CI - 1.950 to - 0.051, P = 0.039). CP cases showed markedly lower Zn level than that in controls among Caucasians (SMD =  - 0.462, 95% CI - 0.650 to - 0.274, P < 10-4). No significant differences of Cu, iron and Ca levels between CP cases and controls among Caucasians (SMD =  - 0.188, 95% CI - 0.412 to 0.037, P = 0.101; SMD =  - 0.004, 95% CI - 0.190 to 0.182, P = 0.968; SMD = 0.070, 95% CI - 0.116 to 0.257, P = 0.459) were observed. No marked difference of Mg level between CP cases and controls was noted among overall populations (SMD =  - 0.139, 95% CI - 0.504 to 0.226, P = 0.455), Asians (SMD =  - 0.131, 95% CI - 0.663 to 0.401, P = 0.629), and Caucasians (SMD =  - 0.074, 95% CI - 0.361 to 0.213, P = 0.614). Sensitivity analysis did not change the overall results significantly for Cu, Zn, iron and Mg. CP cases demonstrated significantly lower levels of Cu/Zn/iron/Ca than those in healthy controls, particularly in Asians. Decreasing trend of Cu/Zn/iron/Ca levels merit attention, particularly in the population with high susceptibility to CP. Frequent monitoring and early intervention may be needed.

Genome-wide DNA methylome and transcriptome changes induced by inorganic nanoparticles in human kidney cells after chronic exposure

The unique physicochemical properties make inorganic nanoparticles (INPs) an exciting tool in diagnosis and disease management. However, as INPs are relatively difficult to fully degrade and excrete, their unintended accumulation in the tissue might result in adverse health effects. Herein, we provide a methylome-transcriptome framework for chronic effects of INPs, commonly used in biomedical applications, in human kidney TH-1 cells. Renal clearance is one of the most important routes of nanoparticle excretion; therefore, a detailed evaluation of nanoparticle-mediated nephrotoxicity is an important task. Integrated analysis of methylome and transcriptome changes induced by INPs (PEG-AuNPs, Fe3O4NPs, SiO2NPs, and TiO2NPs) revealed significantly deregulated genes with functional classification in immune response, DNA damage, and cancer-related pathways. Although most deregulated genes were unique to individual INPs, a relatively high proportion of them encoded the transcription factors. Interestingly, FOS hypermethylation inversely correlating with gene expression was associated with all INPs exposures. Our study emphasizes the need for a more comprehensive investigation of INPs' biological safety, especially after chronic exposure.

The Influence of Copper Nanoparticles on Neurometabolism Marker Levels in the Brain and Intestine in a Rat Model

The aim of this study is to assess the effect of different forms and dosages of copper on the levels of markers depicting the neurodegenerative changes in the brain and the jejunum. The experiment was performed using 40 male Wistar rats fed a typical rat diet with two dosages of Cu used as CuCO₃ (6.5 and 13 mg/kg diet) and dietary addition of two CuNP dosages (standard 6.5 and enhanced 13 mg/kg diet), randomly divided into four groups. The levels of neurodegenerative markers were evaluated. Nanoparticles caused a reduction in the level of glycosylated acetylcholinesterase (GAChE), an increase the level of acetylcholinesterase (AChE) and lipoprotein receptor-related protein 1 (LRP1), a reduction in β-amyloid (βAP) in the brain and in the intestine of rats and a reduction in Tau protein in the brain of rats. The highest levels of AChE, the ATP-binding cassette transporters (ABC) and LRP1 and lower levels of toxic GAChE, β-amyloid, Tau, hyper-phosphorylated Tau protein (p-Tau) and the complex of calmodulin and Ca²⁺ (CAMK2a) were recorded in the tissues of rats receiving a standard dose of Cu. The neuroprotective effect of Cu can be increased by replacing the carbonate form with nanoparticles and there is no need to increase the dose of copper.

The Effect of Nanomaterials on DNA Methylation: A Review

DNA methylation is an epigenetic mechanism that involves the addition of a methyl group to a cytosine residue in CpG dinucleotides, which are particularly abundant in gene promoter regions. Several studies have highlighted the role that modifications of DNA methylation may have on the adverse health effects caused by exposure to environmental toxicants. One group of xenobiotics that is increasingly present in our daily lives are nanomaterials, whose unique physicochemical properties make them interesting for a large number of industrial and biomedical applications. Their widespread use has raised concerns about human exposure, and several toxicological studies have been performed, although the studies focusing on nanomaterials' effect on DNA methylation are still limited. The aim of this review is to investigate the possible impact of nanomaterials on DNA methylation. From the 70 studies found eligible for data analysis, the majority were in vitro, with about half using cell models related to the lungs. Among the in vivo studies, several animal models were used, but most were mice models. Only two studies were performed on human exposed populations. Global DNA methylation analyses was the most frequently applied approach. Although no trend towards hypo- or hyper-methylation could be observed, the importance of this epigenetic mechanism in the molecular response to nanomaterials is evident. Furthermore, methylation analysis of target genes and, particularly, the application of comprehensive DNA methylation analysis techniques, such as genome-wide sequencing, allowed identifying differentially methylated genes after nanomaterial exposure and affected molecular pathways, contributing to the understanding of their possible adverse health effects.

The Effect of Copper Nanoparticles and a Different Source of Dietary Fibre in the Diet on the Integrity of the Small Intestine in the Rat

The aim of the study was to verify the hypothesis regarding the effect of recommended (6.5 mg/kg) or enhanced (13 mg/kg) level of CuNPs in the diet in combination with different types of dietary fibre—cellulose (control), inulin, pectin or psyllium—on selected biological parameters of intestinal integrity in rats. Rats were randomly divided into 10 groups. The first two groups were fed a control diet that contained cellulose, and a mineral mixture with standard or enhanced content of CuCO3. Experimental groups were fed a diet supplemented with CuNPs (6.5 or 13 mg/kg) and combined with different types of fibre (cellulose, pectin, inulin or psyllium). After the feeding period, blood and small intestine samples were collected for further analysis. Replacing CuCO3 by CuNPs in the diet positively reduced the level of lactic acid and apoptosis markers in the small intestine; however, it also resulted in the intensification of DNA oxidation. The most beneficial effect on DNA repair mechanisms is related to inulin, while pectin has the greatest ability to inhibit inflammatory processes that induce the apoptotic death of cells in the small intestine. Our results suggest that dietary fibre supplementation protects the small intestine against potentially harmful, oxidative effects of CuNPs by intensifying the intestinal barrier.

Dietary Copper Deficiency Leads to Changes in Gene Expression Indicating an Increased Demand for NADH in the Prefrontal Cortex of the Rat's Brain

Copper is an essential element to brain cells as it is a cofactor and a structural component of various enzymes involved in energy metabolism pathways. Accumulating evidence points to the pivotal role of copper deficiency in neurodegeneration resulting from impaired copper homeostasis. Despite the indisputable role of copper in mitochondrial respiration, its homeostasis regulation in the brain tissue remains unclear. The assessment of changes in the expression of genes encoding key pathways of energy metabolism can greatly benefit further studies exploring copper’s role in neurodegeneration. Using a rat model, we investigate whether the replacement of the inorganic form of copper with metallic nanoparticles containing copper or complete deprivation of copper from the diet have an impact on the expression of genes involved in energy metabolism in the prefrontal cortex of the rats’ brain. Herein, we indicate that removing inorganic copper from the normal standard diet or the replacement with copper nanoparticles can lead to programmed energy metabolism changes. It can be recognized that some of these changes indicate an increased demand for NADH in the prefrontal cortex of the rat’s brain, probably as a result of adaptation effect.

Effect of Copper Nanoparticles in the Diet of WKY and SHR Rats on the Redox Profile and Histology of the Heart, Liver, Kidney, and Small Intestine

The aim of this experiment was to test the effect of the partial or complete replacement of traditional CuCO₃ in the diet of rats with copper nanoparticles (CuNPs) on the biochemical parameters, redox status, and histomorphometry of their tissues. Normotensive male Wistar–Kyoto rats (WKY) were allocated to three groups. Three analogous groups of spontaneously hypertensive rats (SHR) were also formed. The WKY and SHR rats received copper in a standard daily dose—6.5 mg/kg CuCO₃ or CuNPs (100% replacement) or 3.25 mg/kg CuCO₃ plus 3.25 mg/kg CuNPs (50% replacement)—for 8 weeks. Next, blood, heart, small intestine, liver, and kidney samples were collected. The activity of alanine aminotransferase, aspartate aminotransferase, creatine kinase, and gamma-glutamyl transferase and the content of creatinine and urea acid were measured in the plasma. The collected tissues were subjected to a histological evaluation, and redox status parameters (catalase and superoxide dismutase activity, malondialdehyde and glutathione content) were determined. The replacement of CuCO₃ with CuNPs in the diet may exacerbate the negative changes induced by hypertension in the heart, liver, and intestines. However, it seems that it is only in the case of the liver where the observed changes may be due to an increase in oxidative reactions resulting from the inclusion of CuNPs.

The Role of 20-HETE, COX, Thromboxane Receptors, and Blood Plasma Antioxidant Status in Vascular Relaxation of Copper-Nanoparticle-Fed WKY Rats

Recently, the addition of copper nanoparticles (NPs) in a daily diet (6.5 mg/kg) was studied in different animal models as a possible alternative to ionic forms. Male Wistar-Kyoto rats (24-week-old, n = 11) were fed with copper, either in the form of carbonate salt (Cu_6.5) or metal-based copper NPs (NP_6.5), for 8 weeks. The third group was fed with a half dose of each (NP_3.25 + Cu_3.25). The thoracic aorta and blood plasma was studied. Supplementation with NP_6.5 decreased the Cu (×0.7), Cu/Zn-ratio (×0.6) and catalase (CAT, ×0.7), and increased Zn (×1.2) and superoxide dismutase (SOD, ×1.4). Meanwhile, NP_3.25 + Cu_3.25 decreased the Cu/Zn-ratio (×0.7), and CAT (×0.7), and increased the daily feed intake (×1.06). Preincubation with either the selective cyclooxygenase (COX)-2 inhibitor, or the non-selective COX-1/2 inhibitor attenuated vasodilation of rat thoracic aorta in the NP_6.5 group exclusively. However, an increased vasodilator response was observed in the NP_6.5 and NP_3.25 + Cu_3.25 group of rats after preincubation with an inhibitor of 20-hydroxyeicosatetraenoic acid (20-HETE) formation, and the thromboxane receptor (TP) antagonist. Significant differences were observed between the NP_6.5 and NP_3.25 + Cu_3.25 groups of rats in: dietary intake, acetylcholine-induced vasodilation, and response to COX-inhibitors. Copper NPs in a standard daily dose had more significant effects on the mechanism(s) responsible for the utilization of reactive oxygen species in the blood plasma with the participation of prostanoids derived from COX-2 in the vascular relaxation. Dietary copper NPs in both doses modified vasodilation through the vasoconstrictor 20-HETE and the TP receptors.

The effect of the use of copper carbonate and copper nanoparticles in the diet of rats on the level of β-amyloid and acetylcholinesterase in selected organs

BACKGROUND

Copper has an important role in nervous system function, as a cofactor of many enzymes and in the synthesis of neurotransmitters. Both the dose and the chemical form of copper can determine the impact of this element on metabolism, the neurological system and the immune system.

AIMS

The aim of the study was to determine whether and in what form the addition of copper changes the level of amyloid beta and acetylcholinesterase level in selected rat tissues.

METHODS

Thirty, healthy, male, albino Wistar rats aged 7 weeks were randomly divided into 3 groups. Three experimental treatments were used to evaluate the effects of different levels and sources of Cu (6.5 mg kg of diet) in the diet: Cu₀ - rats fed a diet without Cu supplementation; Cu_salt - rats fed a diet with CuCO₃ (6.5 mg kg of diet) during two months of feeding; Cu_NPs - rats fed a diet with Cu nanoparticles (6.5 mg kg of diet) during two months of feeding. In blood serum and tissue homogenates there rated the indicators proving the potential neurodegenerative effect and epigenetic DNA damage induced by chemical form of copper or lack of additional copper supplementation in diet were determined. There were analysed: level of acetylcholinesterase, β-amyloid, low-density lipoprotein receptor-related protein 1, apyrimidinic endonuclease, thymidine glycosidase, alkylpurine-DNA-N-glycosylase and glycosylated acetylcholinesterase.

RESULTS

Irrespective of the form of copper added, it was found to increase acetylcholinesterase level in the brain, spleen and liver, as well as in the blood plasma of the rats. Copper in the form of CuCO₃ was found to increase acetylcholinesterase level in the kidneys. The addition of both forms of copper caused a marked increase in the plasma concentration of β-amyloid in comparison with the diet with no added Cu. The addition of both forms of copper caused a marked increase in the plasma concentration of β-amyloid in comparison with the diet with no added Cu.

CONCLUSIONS

A lack of added Cu in the diet of rats reduces the concentration of amyloid-β in the blood, whereas administration of copper, in the form of either CuNPs or CuCO₃, increases the level of this peptide in the blood. The use of copper in the form of CuNPs in the diet of rats does not increase the level of β-amyloid more than the use of the carbonate form of this element. The use of CuNPs or CuCO₃ in the diet of rats increases acetylcholinesterase level in the brain, spleen, liver, and blood. CuNPs in the diet of rats were not found to increase acetylcholinesterase level to a greater extent than Cu⁺² carbonate.

Strawberry phenolic extracts effectively mitigated metabolic disturbances associated with high-fat ingestion in rats depending on the ellagitannin polymerization degree

In the present experiment it was hypothesised that dietary strawberry ellagitannin-rich extracts would mitigate negative consequences associated with consumption. Therefore, two extracts rich in dimeric (D-ET) or monomeric (M-ET) ellagitannins (ETs) were added to a standard or high-fat diet fed to rats for four weeks. The D-ET-rich extract contained 82.3% polyphenols, and the M-ET/D-ET ratio was 40 : 60, while the M-ET-rich extract contained 88.0% and 96 : 4, respectively. The experimental feeding with high-fat diets containing extracts resulted in beneficial mitigating effects in the lipid profile, redox status of the rat's liver and blood plasma. According to the accepted hypothesis, the obtained results pointed at increased desired hepatic and plasma modifications when the extract was rich in M-ET, as indicated by favourable changes in the hepatic fat content, GSH and GSSG concentrations and GSH/GSSG ratio as well as blood plasma FRAP, ACL, HDL-cholesterol, and atherogenic coefficient values. These changes were partly connected to the fact that M-ET was more prone vs. D-ET to intestinal microbial conversion into respective metabolites. The urinary daily excretion of ET metabolites and their blood plasma concentrations were higher in rats fed with M-ET vs. D-ET-rich diets. To conclude, the metabolic action of the M-ET-rich extract in the normalization of high-fat-induced disturbances was more pronounced.

Micronutrients and Breast Cancer Progression: A Systematic Review

Epidemiological studies on micronutrient consumption have reported protective associations in the incidence and/or progression of various cancer types. Supplementation with some of these micronutrients has been analyzed, showing chemoprotection, low toxicity, antiproliferation, and the ability to modify epigenetic signatures in various cancer models. This review investigates the reported effects of micronutrient intake or supplementation in breast cancer progression. A PubMed search was conducted with the keywords "micronutrients breast cancer progression", and the results were analyzed. The selected micronutrients were vitamins (C, D, and E), folic acid, metals (Cu, Fe, Se, and Zn), fatty acids, polyphenols, and iodine. The majority of in vitro models showed antiproliferative, cell-cycle arrest, and antimetastatic effects for almost all the micronutrients analyzed, but these effects do not reflect animal or human studies. Only one clinical trial with vitamin D and one pilot study with molecular iodine showed favorable overall survival and disease-free interval.

Effect of Different Levels of Copper Nanoparticles and Copper Sulfate on Morphometric Indices, Antioxidant Status and Mineral Digestibility in the Small Intestine of Turkeys

It was hypothesized that dietary copper (Cu) nanoparticles, as a substitute for the commonly used copper sulfate, could contribute to lowering the dietary inclusion levels of Cu without compromising growth performance or reducing Cu digestibility and utilization in turkeys. An experiment was carried out on 648 one-day-old Hybrid Converter turkeys divided into 6 groups with 6 replicates per group in a two-factorial design with 3 dietary inclusion levels of Cu (20, 10 and 2 mg kg−1) and 2 dietary sources of Cu, copper sulfate and Cu nanoparticles (Cu-SUL and Cu-NPs, respectively). The apparent digestibility coefficients of minerals were determined after 6 weeks, and tissue samples were collected after 14 weeks of experimental feeding. A decrease in the dietary inclusion levels of Cu from 20 to 10 and 2 mg kg−1 did not reduce the body weights of turkeys at 42 and 98 days of age. In comparison with the remaining treatments, the lowest dietary inclusion level of Cu significantly decreased MDA concentrations in small intestinal tissue (P=0.002) and in the bursa of Fabricius (P=0.001). The replacement of Cu-SUL with Cu-NPs differentially modulated the redox status of selected tissues, i.e., enhanced SOD activity in small intestinal tissue (P=0.001) and decreased total glutathione levels in the bursa of Fabricius (P=0.005). In general, neither the different levels nor sources of additional dietary Cu (main factors) exerted negative effects on the histological structure of the duodenum and jejunum in turkeys. The intestinal digestibility of Cu increased with decreasing dietary Cu levels, and as a consequence, the highest apparent digestibility coefficient of Cu (and zinc) was noted in turkeys fed diets with the addition of 2 mg kg−1 Cu-NPs. Therefore, the environmental burden of excreted Cu was substantially reduced along with decreasing dietary Cu levels but it did not depend on the Cu source.

The Effect of a Rat Diet Without Added Cu on Redox Status in Tissues and Epigenetic Changes in the Brain

The aim of the study was to determine whether feeding rats a diet without added Cu increases oxidation of macromolecules in tissues, as well as epigenetic changes in the brain. The rats were divided into two groups: the Cu-6.5 group which was fed a diet with a standard content of Cu in mineral mixture – 6.5 mg Cu from CuCO3 per kg of diet; and the Cu-0 group which was fed a diet with a mineral mix without Cu supplementation. At the end of the experiment the rats were weighed and blood samples were collected. Finally, the rats were euthanized and then the liver, small intestine, spleen, kidneys, heart, brain, lung, testes and leg muscles were removed and weighed. In the blood of Cu-0 rats the lower Cp activity and greater GPx and CAT activity than in Cu-6.5 rats were noticed. In the liver, lungs, heart and testes of Cu-0 rats, a decreased content of Cu were noticed. Application of Cu-0 diets resulted in increased LOOH level in the small intestine, liver, and heart, as well as increased MDA content in the liver, spleen, lungs, brain and testes. The Cu-0 treatment caused a decrease in SOD activity in the heart, lungs and testes of the rats and a decrease in CAT activity in the small intestine. In the brain and testes of rats from the Cu-0 treatment, lower content of GSH + GSSG was observed. The brain of rats from the Cu-0 treatment showed an increase in the level of PCs, 8-OHdG, Casp 8 and DNA methylation. The research has shown that a deficiency of Cu in the diet impairs the body’s antioxidant defences, which in turn leads to increased lipid oxidation in the liver, small intestinal wall, heart, spleen, lungs, brain and testes, as well as to oxidation of proteins and DNA in the brain. A deficiency of Cu in the diet also increases methylation of cytosine in the brain.

The effect of different dietary ratios of lysine and arginine in diets with high or low methionine levels on oxidative and epigenetic DNA damage, the gene expression of tight junction proteins and selected metabolic parameters in Clostridium perfringens-challenged turkeys

Two experiments were performed to investigate the effect of different ratios of arginine (Arg) to lysine (Lys) in diets with low (30% Lys; Experiment 1) and high (45% Lys; Experiment 2) methionine (Met) levels on selected metabolic parameters, oxidative and epigenetic DNA damage, and the mechanisms underlying intestinal barrier integrity in turkeys challenged with Clostridium perfringens. In each experiment, 108 one-day-old Hybrid Converter female turkeys were placed in 6 pens (18 birds per pen) and reared for 42 days. At 34, 36 and 37 days of age, half of the birds were subjected to C. perfringens challenge. A 3 × 2 factorial design with three levels of Arg relative to Lys (90, 100 and 110%; Arg₉₀, Arg₁₀₀ and Arg₁₁₀, respectively) and C. perfringens infection (-, +) was employed. Challenging birds with C. perfringens increased lipid oxidation and the oxidation and methylation of DNA of intestinal mucosa, and down-regulated the activities of DNA-repairing enzymes. Neither the dietary treatment nor the challenge affected the markers of liver function or metabolism. Arg₁₁₀ diets with the high Met level induced DNA oxidation and methylation whereas these processes were downregulated in birds fed Arg₉₀ diets. The results indicate that Arg₉₀ diets with high Met levels have a beneficial influence on the indicators of intestinal barrier integrity in turkeys with necrotic enteritis (NE). Despite the analyzed amino acid ratios interacted with the systems responsible for the maintenance of gut integrity in the host organism, this dietary intervention probably enabled birds to cope with NE.

DNA Methylation Profiles in a Group of Workers Occupationally Exposed to Nanoparticles

The risk of exposure to nanoparticles (NPs) has rapidly increased during the last decade due to the vast use of nanomaterials (NMs) in many areas of human life. Despite this fact, human biomonitoring studies focused on the effect of NP exposure on DNA alterations are still rare. Furthermore, there are virtually no epigenetic data available. In this study, we investigated global and gene-specific DNA methylation profiles in a group of 20 long-term (mean 14.5 years) exposed, nanocomposite, research workers and in 20 controls. Both groups were sampled twice/day (pre-shift and post-shift) in September 2018. We applied Infinium Methylation Assay, using the Infinium MethylationEPIC BeadChips with more than 850,000 CpG loci, for identification of the DNA methylation pattern in the studied groups. Aerosol exposure monitoring, including two nanosized fractions, was also performed as proof of acute NP exposure. The obtained array data showed significant differences in methylation between the exposed and control groups related to long-term exposure, specifically 341 CpG loci were hypomethylated and 364 hypermethylated. The most significant CpG differences were mainly detected in genes involved in lipid metabolism, the immune system, lung functions, signaling pathways, cancer development and xenobiotic detoxification. In contrast, short-term acute NP exposure was not accompanied by DNA methylation changes. In summary, long-term (years) exposure to NP is associated with DNA epigenetic alterations.

Dietary supplementation with copper nanoparticles influences the markers of oxidative stress and modulates vasodilation of thoracic arteries in young Wistar rats

We aimed to study the physiological effects of diet supplemented with copper (Cu) nanoparticles (NPs). During the eight weeks of the experiment, young Wistar rats (at seven weeks of age, n = 9) were supplemented with 6.5 mg of Cu either as NPs or carbonate salt (Cu6.5). A diet that was not supplemented with Cu served as a negative control (Cu0). The impact of nano Cu supplementation on lipid (reflected as thiobarbituric acid reactive substances-TBARS) and protein peroxidation (thiol and carbonyl groups) in blood plasma as well as the influence on the vasodilatory mechanism(s) of isolated rat thoracic arteries were studied. Supplementation with Cu enhanced lipid peroxidation (TBARS) in NP6.5 (x2.4) and in Cu6.5 (x1.9) compared to the negative control. Significant increase in TBARS was also observed in NP6.5 (x1.3) compared to the Cu6.5 group. The level of thiol groups increased in NP6.5 (x1.6) compared to Cu6.5. Meanwhile, significant (x0.6) decrease was observed in the Cu6.5 group compared to the negative control. Another marker of protein oxidation, carbonyl groups increased in NP6.5 (x1.4) and Cu6.5 (x2.3) compared to the negative control. However significant difference (x0.6) was observed between NP6.5 and Cu6.5. Arteries from Cu supplemented rats exhibited an enhanced vasodilation to gasotransmitters: nitric oxide (NO) and carbon monoxide (CO). An enhanced vasodilation to NO was reflected in the increased response to acetylcholine (ACh) and calcium ionophore A23187. The observed responses to ACh and CO releasing molecule (CORM-2) were more pronounced in NP6.5. The activator of cGMP-dependent protein kinases (8-bromo-cGMP) induced similar vasodilation of thoracic arteries in NP6.5 and Cu0 groups, while an increased response was observed in the Cu6.5 group. Preincubation with the inducible nitric oxide (iNOS) synthase inhibitor- 1400W, decreased the ACh-induced vasodilation in NP6.5, exclusively. Meanwhile the eicosanoid metabolite of arachidonic acid (20-HETE) synthesis inhibitor-HET0016, enhanced vasodilation of arteries from Cu0 group. In conclusion, this study demonstrates that supplementation with nano Cu influences oxidative stress, which further has modified the vascular response.

The interaction between resveratrol and two forms of copper as carbonate and nanoparticles on antioxidant mechanisms and vascular function in Wistar rats

BACKGROUND

Experimental studies have emphasized that cardiovascular alterations can be improved by the long-term use of resveratrol (trans-3,5,4'-trihydroxystilbene; RSV) as well as dietary copper (Cu) intake.

METHODS

Male Wistar rats were supplemented for 8 weeks with Cu (6.5 mg/kg diet) as either nanoparticles (40 nm, CuNPs) or carbonate (CuCO3). Half of the studied animals were supplemented with RSV (500 mg/kg diet). Vascular function and blood plasma antioxidant status, expressed as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), lipid hydroperoxides (LOOH) and malondialdehyde (MDA) were analyzed. The activity of ceruloplasmin (Cp), lipid profile, fasting glucose, and concentrations of Cu and zinc (Zn) were analyzed.

RESULTS

RSV supplementation resulted in the elevated activity of SOD and decreased CAT, GPx and LDL-cholesterol in both groups. RSV supplementation on CuNPs increased the participation of vasoconstrictor prostanoids and decreased ACh-induced vasodilation, while the participation of hyperpolarizing mechanism(s) was restored by activating KATP channels. Blood plasma glucose was decreased. RSV supplementation on CuCO3 enhanced ACh- and SNP-induced vasodilation and decreased NA-induced vasoconstriction. The lipid profile was improved, as well as Zn concentration. Meanwhile, Cu and Cp, and the markers of lipid peroxidation, reflected as LOOH and MDA, were decreased.

CONCLUSION

The use of RSV during CuCO3 intake improves vascular responses, the lipid profile and the antioxidant mechanism(s). The beneficial role of RSV was not observed in the CuNP group and decreased ACh-induced vasodilation and increased participation of vasoconstrictor prostanoids in the vascular regulation were noticed.

Epigenetic Aspects of Engineered Nanomaterials: Is the Collateral Damage Inevitable?

The extensive application of engineered nanomaterial (ENM) in various fields increases the possibilities of human exposure, thus imposing a huge risk of nanotoxicity. Hence, there is an urgent need for a detailed risk assessment of these ENMs in response to their toxicological profiling, predominantly in biomedical and biosensor settings. Numerous "toxico-omics" studies have been conducted on ENMs, however, a specific "risk assessment paradigm" dealing with the epigenetic modulations in humans owing to the exposure of these modern-day toxicants has not been defined yet. This review aims to address the critical aspects that are currently preventing the formation of a suitable risk assessment approach for/against ENM exposure and pointing out those researches, which may help to develop and implement effective guidance for nano-risk assessment. Literature relating to physicochemical characterization and toxicological behavior of ENMs were analyzed, and exposure assessment strategies were explored in order to extrapolate opportunities, challenges, and criticisms in the establishment of a baseline for the risk assessment paradigm of ENMs exposure. Various challenges, such as uncertainty in the relation of the physicochemical properties and ENM toxicity, the complexity of the dose-response relationships resulting in difficulty in its extrapolation and measurement of ENM exposure levels emerged as issues in the establishment of a traditional risk assessment. Such an appropriate risk assessment approach will provide adequate estimates of ENM exposure risks and will serve as a guideline for appropriate risk communication and management strategies aiming for the protection and the safety of humans.

The effect of the source and dosage of dietary Cu on redox status in rat tissues

The aim of this experiment was to investigate whether the amount of Cu added to the diet of rats can be reduced without adversely affecting the antioxidant status of tissues and growth, and whether copper nanoparticles can be used for this purpose. For four weeks, four experimental groups of rats were fed diets with two dosages of added Cu (standard-6.5 or 3.25 mg/kg) in two forms (standard-CuCO₃ or copper nanoparticles). Replacing the CuCO₃ supplement with CuNPs resulted in a decreased lung weight and an increased Cu content in brain, kidney and lung, intensification of lipid peroxidation processes, and weakened antioxidant defence in the lungs and kidneys. This treatment also reduced the Cu content in heart, level of lipid oxidation in the liver and testes and improved antioxidant defence in the brain. Reducing the addition of Cu to the diet from 6.5 to 3.25 mg/kg reduced lung weight and increased lipid peroxidation in the liver, heart and lungs, and also weakened antioxidant defence in the lungs and testes. This treatment also weakened the lipid peroxidation process in the spleen, small intestine and brain and strengthened the antioxidant defence of the brain and kidneys. In conclusion, replacing CuCO₃ with CuNPs and reducing the level of Cu in the diet of rats has a particularly unfavourable effect on the respiratory system, causing adverse changes in the lungs. However, these treatments have a clearly positive effect on the redox status of the liver and brain.