Miroslava Kuricova

Coating-dependent induction of cytotoxicity and genotoxicity of iron oxide nanoparticles

Abstract Surface coatings of nanoparticles (NPs) are known to influence advantageous features of NPs as well as potential toxicity. Iron oxide (Fe3O4) NPs are applied for both medical diagnostics and targeted drug delivery. We investigated the potential cytotoxicity and genotoxicity of uncoated iron oxide (U-Fe3O4) NPs in comparison with oleate-coated iron oxide (OC-Fe3O4) NPs. Testing was performed in vitro in human lymphoblastoid TK6 cells and in primary human blood cells. For cytotoxicity testing, relative growth activity, trypan blue exclusion, 3H-thymidine incorporation and cytokinesis-block proliferation index were assessed. Genotoxicity was evaluated by the alkaline comet assay for detection of strand breaks and oxidized purines. Particle characterization was performed in the culture medium. Cellular uptake, morphology and pathology were evaluated by electron microscopy. U-Fe3O4 NPs were found not to be cytotoxic (considering interference of NPs with proliferation test) or genotoxic under our experimental conditions. In contrast, OC-Fe3O4 NPs were cytotoxic in a dose-dependent manner, and also induced DNA damage, indicating genotoxic potential. Intrinsic properties of sodium oleate were excluded as a cause of the toxic effect. Electron microscopy data were consistent with the cytotoxicity results. Coating clearly changed the behaviour and cellular uptake of the NPs, inducing pathological morphological changes in the cells.

Towards an alternative testing strategy for nanomaterials used in nanomedicine: Lessons from NanoTEST

Abstract In spite of recent advances in describing the health outcomes of exposure to nanoparticles (NPs), it still remains unclear how exactly NPs interact with their cellular targets. Size, surface, mass, geometry, and composition may all play a beneficial role as well as causing toxicity. Concerns of scientists, politicians and the public about potential health hazards associated with NPs need to be answered. With the variety of exposure routes available, there is potential for NPs to reach every organ in the body but we know little about the impact this might have. The main objective of the FP7 NanoTEST project (www.nanotest-fp7.eu) was a better understanding of mechanisms of interactions of NPs employed in nanomedicine with cells, tissues and organs and to address critical issues relating to toxicity testing especially with respect to alternatives to tests on animals. Here we describe an approach towards alternative testing strategies for hazard and risk assessment of nanomaterials, highlighting the adaptation of standard methods demanded by the special physicochemical features of nanomaterials and bioavailability studies. The work has assessed a broad range of toxicity tests, cell models and NP types and concentrations taking into account the inherent impact of NP properties and the effects of changes in experimental conditions using well-characterized NPs. The results of the studies have been used to generate recommendations for a suitable and robust testing strategy which can be applied to new medical NPs as they are developed.

Immunotoxicity and genotoxicity testing of PLGA-PEO nanoparticles in human blood cell model

Abstract A human blood cell model for immunotoxicity and genotoxicity testing was used to measure the response to polylactic-co-glycolic acid (PLGA-PEO) nanoparticle (NP) (0.12, 3, 15 and 75 μg/cm2 exposure in fresh peripheral whole blood cultures/isolated peripheral blood mononuclear cell cultures from human volunteers (n = 9–13). PLGA-PEO NPs were not toxic up to dose 3 μg/cm2; dose of 75 μg/cm2 displays significant decrease in [3H]-thymidine incorporation into DNA of proliferating cells after 4 h (70% of control) and 48 h (84%) exposure to NPs. In non-cytotoxic concentrations, in vitro assessment of the immunotoxic effects displayed moderate but significant suppression of proliferative activity of T-lymphocytes and T-dependent B-cell response in cultures stimulated with PWM > CON A, and no changes in PHA cultures. Decrease in proliferative function was the most significant in T-cells stimulated with CD3 antigen (up to 84%). Cytotoxicity of natural killer cells was suppressed moderately (92%) but significantly in middle-dosed cultures (4 h exposure). On the other hand, in low PLGA-PEO NPs dosed cultures, significant stimulation of phagocytic activity of granulocytes (119%) > monocytes (117%) and respiratory burst of phagocytes (122%) was recorded. Genotoxicity assessment revealed no increase in the number of micronucleated binucleated cells and no induction of SBs or oxidised DNA bases in PLGA-PEO-treated cells. To conclude on immuno- and genotoxicity of PLGA-PEO NPs, more experiments with various particle size, charge and composition need to be done.

Modulation of DNA repair capacity and mRNA expression levels of XRCC1, hOGG1 and XPC genes in styrene-exposed workers

Decreased levels of single-strand breaks in DNA (SSBs), reflecting DNA damage, have previously been observed with increased styrene exposure in contrast to a dose-dependent increase in the base-excision repair capacity. To clarify further the above aspects, we have investigated the associations between SSBs, micronuclei, DNA repair capacity and mRNA expression in XRCC1, hOGG1 and XPC genes on 71 styrene-exposed and 51 control individuals. Styrene concentrations at workplace and in blood characterized occupational exposure. The workers were divided into low (below 50 mg/m³) and high (above 50 mg/m³)) styrene exposure groups. DNA damage and DNA repair capacity were analyzed in peripheral blood lymphocytes by Comet assay. The mRNA expression levels were determined by qPCR. A significant negative correlation was observed between SSBs and styrene concentration at workplace (R=-0.38, p=0.001); SSBs were also significantly higher in men (p=0.001). The capacity to repair irradiation-induced DNA damage was the highest in the low exposure group (1.34±1.00 SSB/10⁹ Da), followed by high exposure group (0.72±0.81 SSB/10⁹ Da) and controls (0.65±0.82 SSB/10⁹ Da). The mRNA expression levels of XRCC1, hOGG1 and XPC negatively correlated with styrene concentrations in blood and at workplace (p<0.001) and positively with SSBs (p<0.001). Micronuclei were not affected by styrene exposure, but were higher in older persons and in women (p<0.001). In this study, we did not confirm previous findings on an increased DNA repair response to styrene-induced genotoxicity. However, negative correlations of SSBs and mRNA expression levels of XRCC1, hOGG1 and XPC with styrene exposure warrant further highly-targeted study.

Hydrophobic sodium fluoride-based nanocrystals doped with lanthanide ions: assessment of in vitro toxicity to human blood lymphocytes and phagocytes.

In vitro immunotoxicity of hydrophobic sodium fluoride‐based nanocrystals (NCs) doped with lanthanide ions was examined in this study. Although there is already a significant amount of optical and structural data on NaYF4 NCs, data on safety assessment are missing. Therefore, peripheral whole blood from human volunteers was used to evaluate the effect of 25 and 30 nm hydrophobic NaYF4 NCs dissolved in cyclohexane (CH) on lymphocytes, and of 10 nm NaYF4 NCs on phagocytes. In the concentration range 0.12–75 µg cm−2 (0.17–106 µg ml−1), both 25 and 30nm NaYF4 NCs did not induce cytotoxicity when measured as incorporation of [3H]‐thymidine into DNA. Assessment of lymphocyte function showed significant suppression of the proliferative activity of T‐lymphocytes and T‐dependent B‐cell response in peripheral blood cultures (n = 7) stimulated in vitro with mitogens phytohemagglutinin (PHA) and pokeweed (PWM) (PHA > PWM). No clear dose–response effect was observed. Phagocytic activity and respiratory burst of leukocytes (n = 5–8) were generally less affected. A dose‐dependent suppression of phagocytic activity of granulocytes in cultures treated with 25 nm NCs was observed (vs. medium control). A decrease in phagocytic activity of monocytes was found in cells exposed to higher doses of 10 and 30 nm NCs. The respiratory burst of phagocytes was significantly decreased by exposure to the middle dose of 30 nm NCs only. In conclusion, our results demonstrate immunotoxic effects of hydrophobic NaYF4 NCs doped with lanthanide ions to lymphocytes and to lesser extent to phagocytes. Further research needs to be done, particularly faze transfer of hydrophobic NCs to hydrophilic ones, to eliminate the solvent effect. Copyright

Functionalized porous silica&maghemite core-shell nanoparticles for applications in medicine: design, synthesis, and immunotoxicity

Aim To determine cytotoxicity and effect of silica-coated magnetic nanoparticles (MNPs) on immune response, in particular lymphocyte proliferative activity, phagocytic activity, and leukocyte respiratory burst and in vitro production of interleukin-6 (IL-6) and 8 (IL-8), interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), and granulocyte macrophage colony stimulating factor (GM-CSF). Methods Maghemite was prepared by coprecipitation of iron salts with ammonia, oxidation with NaOCl and modified by tetramethyl orthosilicate and aminosilanes. Particles were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier-transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). Cytotoxicity and lymphocyte proliferative activity were assessed using [3H]-thymidine incorporation into DNA of proliferating human peripheral blood cells. Phagocytic activity and leukocyte respiratory burst were measured by flow cytometry; cytokine levels in cell supernatants were determined by ELISA. Results γ-Fe2O3&SiO2-NH2 MNPs were 13 nm in size. According to TEM, they were localized in the cell cytoplasm and extracellular space. Neither cytotoxic effect nor significant differences in T-lymphocyte and T-dependent B-cell proliferative response were found at particle concentrations 0.12-75 μg/cm2 after 24, 48, and 72 h incubation. Significantly increased production of IL-6 and 8, and GM-CSF cytokines was observed in the cells treated with 3, 15, and 75 µg of particles/cm2 for 48 h and stimulated with pokeweed mitogen (PHA). No significant changes in TNF-α and IFN-γ production were observed. MNPs did not affect phagocytic activity of monocytes and granulocytes when added to cells for 24 and 48 h. Phagocytic respiratory burst was significantly enhanced in the cultures exposed to 75 µg MNPs/cm2 for 48 h. Conclusions The cytotoxicity and in vitro immunotoxicity were found to be minimal in the newly developed porous core-shell γ-Fe2O3&SiO2-NH2 magnetic nanoparticles.

Immunotoxic and cancerostatic effects of ethyl-4-isothiocyanatobutanoate in female Lewis rats with implanted fibrosarcoma

Isothiocyanates (ITCs) have been isolated from plants. Naturally occurring and synthetic ITCs are known as effective chemopreventive agents. Ethyl 4-isothiocyanatobutanoate (E-41B) is a derivative of gamma-aminobutyric acid. Immunotoxic and canocerostatic effects of E-41B in female inbred Lewis rats implanted with experimental fibrosarcoma BP6-TU2 was evaluated in this study. On day 5 after subcutaneous application of tumor cells, animals started to be treated intraperitoneally three times a week with two different doses of E-41B: 28 and 35 mg/kg/day during 28 days. High dose of E-41B was close to maximum tolerated dose (MTD). Control groups of rats with or without tumors injected intraperitoneally only saline or 70% dimethylsulphoxide were added. Administrating of E-41B resulted in suppression of thymus, popliteal lymph node, spleen weight and spleen cellularity. Hematologic evaluation displayed decreased erythrocyte (ERY) count and level of hemoglobin (HB) in rats treated withE-41B. Immune assays--the phagocytic activity of polymorphonuclear leukocytes (PMN) and monocytes, primary antibody response and in vitro proliferative activity of spleen lymphocytes (LY) to mitogens were not significantly affected by E-41B treatment E-41B moderately decreased tumor weights, but this decrease was not statistically significant in comparison with DMSO-exposed rats with tumors. The fibrosarcoma implantation itself increased significantly spleen weight and changed hematological parameters (decreased HB, increased mean cell volume of ERY, increased leukocyte count, increased % PMN, decreased % LY, decreased % EO). Moreover, moderate decreased percentage of CD161+ positive cells (NK cells) were found in peripheral blood. Immune assays showed decline in proliferation of lymphocytes and phagocytic activity of leukocytes. Our findings indicate that administration of E-41B displayed hematoxic effect in rats implanted with fibrosarcoma. Immunotoxic effect was shown as decreased lymphoid organ weight and spleen cytotoxicity although function of immune cells was not impaired.

Impact of IL13 Genetic Polymorphism Arg130Gln on Total Serum IgE Levels and IFN-γ Gene Expression.

This cross‐sectional study was designed to investigate the extent of genetic susceptibility by targeting variants in interleukin (IL)−4/IL‐13 signalling pathways leading to atopic disease in early childhood. We evaluated involvement of five single nucleotide polymorphisms IL4 C‐590T, IL13 C‐1055T, IL13 Arg130Gln, IL4RA Ile50Val and IL4RA Gln576Arg, in the control of serum total and antigen‐specific immunoglobulin (Ig)E levels. Furthermore, we analysed their association with changes in gene expression of five cytokines having key roles in inflammatory and anti‐inflammatory immune response [IL‐4, IL‐13, interferon (IFN)‐γ, IL‐8 and IL‐10]. Total and antigen‐specific IgE levels in serum and gene expression of selected cytokines in peripheral blood were measured in 386 children aged 1–8 years. TaqMan allelic discrimination, amplification refractory mutation system–polymerase chain reaction (ARMS–PCR) and restriction fragment length polymorphisms (RFLP) methods validated by sequencing were used for genotyping. All genotypes for children with total and antigen‐specific IgE levels in the normal range were in Hardy–Weinberg equilibrium. Gene expression analyses were carried out using TaqMan gene expression assays. We found elevated total IgE levels in carriers of IL13 Arg130Gln variant allele [odds ratio (OR) = 1·84; 95% confidence interval (CI) = 1·16‐2·93]. This effect was more apparent for boys (OR = 2·31; 95% CI = 1·25‐4·28). However, no significant association was observed for the other four variants examined. We found up‐regulation of IFN‐γ in children with elevated serum total IgE levels carrying the Arg130 allele (P = 0·005). No differences were found for IL4, IL8 or IL10, while IL13 gene expression was under the detection limit. IL13 Arg130Gln genotypes can play a role in genetic susceptibility to allergy via regulation of serum total IgE levels and affecting IFN‐γ gene expression.

Impact of interleukin 13 (IL13) genetic polymorphism Arg130Gln on total serum immunoglobulin (IgE) levels and interferon (IFN)‐γ gene expression

This cross‐sectional study was designed to investigate the extent of genetic susceptibility by targeting variants in interleukin (IL)−4/IL‐13 signalling pathways leading to atopic disease in early childhood. We evaluated involvement of five single nucleotide polymorphisms IL4 C‐590T, IL13 C‐1055T, IL13 Arg130Gln, IL4RA Ile50Val and IL4RA Gln576Arg, in the control of serum total and antigen‐specific immunoglobulin (Ig)E levels. Furthermore, we analysed their association with changes in gene expression of five cytokines having key roles in inflammatory and anti‐inflammatory immune response [IL‐4, IL‐13, interferon (IFN)‐γ, IL‐8 and IL‐10]. Total and antigen‐specific IgE levels in serum and gene expression of selected cytokines in peripheral blood were measured in 386 children aged 1–8 years. TaqMan allelic discrimination, amplification refractory mutation system–polymerase chain reaction (ARMS–PCR) and restriction fragment length polymorphisms (RFLP) methods validated by sequencing were used for genotyping. All genotypes for children with total and antigen‐specific IgE levels in the normal range were in Hardy–Weinberg equilibrium. Gene expression analyses were carried out using TaqMan gene expression assays. We found elevated total IgE levels in carriers of IL13 Arg130Gln variant allele [odds ratio (OR) = 1·84; 95% confidence interval (CI) = 1·16‐2·93]. This effect was more apparent for boys (OR = 2·31; 95% CI = 1·25‐4·28). However, no significant association was observed for the other four variants examined. We found up‐regulation of IFN‐γ in children with elevated serum total IgE levels carrying the Arg130 allele (P = 0·005). No differences were found for IL4, IL8 or IL10, while IL13 gene expression was under the detection limit. IL13 Arg130Gln genotypes can play a role in genetic susceptibility to allergy via regulation of serum total IgE levels and affecting IFN‐γ gene expression.

In Vitro Toxicity Of Indoor Fungi From DwellingsIn Slovakia: Testing On The Isolated Lung Cells

The lung is the target organ of multiple aggressions due to environmental noxious substances, indoor pollution, occupational hazards and personal risk such as cigarette smoke. Metabolites produced by different fungus species can also be present the inhaled air. Their effects are not frequently studied in the lung or in the lung cells. Our study focused on the effects of metabolites (both exoand endometabolites) produced by Aspergillus ustus, Aspergillus versicolor, Penicillium chrysogenum and Stachybotrys chartarum isolated from dwellings in Slovakia. Their effects were studied in vitro on alveolar macrophages and epithelial type II cells isolated from Wistar rats and Clara cells isolated from mice. Alveolar macrophages represent a free living population in the alveolar spaces and play an important role in maintaining clean and sterile alveoli; they contribute also to the production of proinflammatory cytokines. Epithelial type II cells play a critical role in preserving the functional integrity of the alveolar surface and they also produce cytokines. The effects of metabolites were evaluated by estimating their cytotoxicity, the activity of lysosomal enzyme acid phosphatase in alveolar macrophages. Lectins were used for studying the changes on cell surface. The production of cytokines (Monocyte Chemoatractant Protein 1MCP-1 and Tumor Necrosis Factor α – TNF-α) was also measured. The effects of metabolites were dose dependent, the highest toxicity was evoked by Stachybotrys chartarum metabolites.