Titanium Dioxide Nanoparticles Modulate Systemic Immune Response and Increase Levels of Reduced Glutathione in Mice after Seven-Week Inhalation

Titanium dioxide nanoparticles (TiO₂ NPs) are used in a wide range of applications. Although inhalation of NPs is one of the most important toxicologically relevant routes, experimental studies on potential harmful effects of TiO₂ NPs using a whole-body inhalation chamber model are rare. In this study, the profile of lymphocyte markers, functional immunoassays, and antioxidant defense markers were analyzed to evaluate the potential adverse effects of seven-week inhalation exposure to two different concentrations of TiO₂ NPs (0.00167 and 0.1308 mg TiO₂/m³) in mice. A dose-dependent effect of TiO₂ NPs on innate immunity was evident in the form of stimulated phagocytic activity of monocytes in low-dose mice and suppressed secretory function of monocytes (IL-18) in high-dose animals. The effect of TiO₂ NPs on adaptive immunity, manifested in the spleen by a decrease in the percentage of T-cells, a reduction in T-helper cells, and a dose-dependent decrease in lymphocyte cytokine production, may indicate immunosuppression in exposed mice. The dose-dependent increase in GSH concentration and GSH/GSSG ratio in whole blood demonstrated stimulated antioxidant defense against oxidative stress induced by TiO₂ NP exposure.

Copper Oxide Nanoparticles Stimulate the Immune Response and Decrease Antioxidant Defense in Mice After Six-Week Inhalation

Copper oxide nanoparticles (CuO NPs) are increasingly used in various industry sectors. Moreover, medical application of CuO NPs as antimicrobials also contributes to human exposure. Their toxicity, including toxicity to the immune system and blood, raises concerns, while information on their immunotoxicity is still very limited. The aim of our work was to evaluate the effects of CuO NPs (number concentration 1.40×106 particles/cm3, geometric mean diameter 20.4 nm) on immune/inflammatory response and antioxidant defense in mice exposed to 32.5 µg CuO/m3 continuously for 6 weeks. After six weeks of CuO NP inhalation, the content of copper in lungs and liver was significantly increased, while in kidneys, spleen, brain, and blood it was similar in exposed and control mice. Inhalation of CuO NPs caused a significant increase in proliferative response of T-lymphocytes after mitogenic stimulation and basal proliferative activity of splenocytes. CuO NPs significantly induced the production of IL-12p70, Th1-cytokine IFN-γ and Th2-cytokines IL-4, IL-5. Levels of TNF-α and IL-6 remained unchanged. Immune assays showed significantly suppressed phagocytic activity of granulocytes and slightly decreased respiratory burst. No significant differences in phagocytosis of monocytes were recorded. The percentage of CD3+, CD3+CD4+, CD3+CD8+, and CD3-CD19+ cell subsets in spleen, thymus, and lymph nodes did not differ between exposed and control animals. No changes in hematological parameters were found between the CuO NP exposed and control groups. The overall antioxidant protection status of the organism was expressed by evaluation of GSH and GSSG concentrations in blood samples. The experimental group exposed to CuO NPs showed a significant decrease in GSH concentration in comparison to the control group. In summary, our results indicate that sub-chronic inhalation of CuO NPs can cause undesired modulation of the immune response. Stimulation of adaptive immunity was indicated by activation of proliferation and secretion functions of lymphocytes. CuO NPs elicited pro-activation state of Th1 and Th2 lymphocytes in exposed mice. Innate immunity was affected by impaired phagocytic activity of granulocytes. Reduced glutathione was significantly decreased in mice exposed to CuO NPs.

Copper Oxide Nanoparticles Stimulate the Immune Response and Decrease Antioxidant Defense in Mice After Six-Week Inhalation

Copper oxide nanoparticles (CuO NPs) are increasingly used in various industry sectors. Moreover, medical application of CuO NPs as antimicrobials also contributes to human exposure. Their toxicity, including toxicity to the immune system and blood, raises concerns, while information on their immunotoxicity is still very limited. The aim of our work was to evaluate the effects of CuO NPs (number concentration 1.40×10⁶ particles/cm³, geometric mean diameter 20.4 nm) on immune/inflammatory response and antioxidant defense in mice exposed to 32.5 µg CuO/m³ continuously for 6 weeks. After six weeks of CuO NP inhalation, the content of copper in lungs and liver was significantly increased, while in kidneys, spleen, brain, and blood it was similar in exposed and control mice. Inhalation of CuO NPs caused a significant increase in proliferative response of T-lymphocytes after mitogenic stimulation and basal proliferative activity of splenocytes. CuO NPs significantly induced the production of IL-12p70, Th1-cytokine IFN-γ and Th2-cytokines IL-4, IL-5. Levels of TNF-α and IL-6 remained unchanged. Immune assays showed significantly suppressed phagocytic activity of granulocytes and slightly decreased respiratory burst. No significant differences in phagocytosis of monocytes were recorded. The percentage of CD3⁺, CD3⁺CD4⁺, CD3⁺CD8⁺, and CD3^-CD19⁺ cell subsets in spleen, thymus, and lymph nodes did not differ between exposed and control animals. No changes in hematological parameters were found between the CuO NP exposed and control groups. The overall antioxidant protection status of the organism was expressed by evaluation of GSH and GSSG concentrations in blood samples. The experimental group exposed to CuO NPs showed a significant decrease in GSH concentration in comparison to the control group. In summary, our results indicate that sub-chronic inhalation of CuO NPs can cause undesired modulation of the immune response. Stimulation of adaptive immunity was indicated by activation of proliferation and secretion functions of lymphocytes. CuO NPs elicited pro-activation state of Th1 and Th2 lymphocytes in exposed mice. Innate immunity was affected by impaired phagocytic activity of granulocytes. Reduced glutathione was significantly decreased in mice exposed to CuO NPs.

Nontuberculous Mycobacteria Prevalence in Aerosol and Spiders' Webs in Karst Caves: Low Risk for Speleotherapy

A total of 152 aerosol and spider web samples were collected: 96 spider’s webs in karst areas in 4 European countries (Czech Republic, France, Italy, and Slovakia), specifically from the surface environment (n = 44), photic zones of caves (n = 26), and inside (aphotic zones) of caves (n = 26), 56 Particulate Matter (PM) samples from the Sloupsko-Sosuvsky Cave System (speleotherapy facility; n = 21) and from aerosol collected from the nearby city of Brno (n = 35) in the Czech Republic. Nontuberculous mycobacteria (NTM) were isolated from 13 (13.5%) spider’s webs: 5 isolates of saprophytic NTM (Mycobacterium gordonae, M. kumamotonense, M. terrae, and M. terrae complex) and 6 isolates of potentially pathogenic NTM (M. avium ssp. hominissuis, M. fortuitum, M. intracellulare, M. peregrinum and M. triplex). NTM were not isolated from PM collected from cave with the speleotherapy facility although mycobacterial DNA was detected in 8 (14.3%) samples. Temperature (8.2 °C, range 8.0–8.4 °C) and relative humidity (94.7%, range 93.6–96.6%) of air in this cave were relatively constant. The average PM_2.5 and PM₁₀ mass concentration was 5.49 µg m⁻³ and 11.1 µg m⁻³. Analysed anions (i.e., F⁻, Cl⁻, NO₂⁻, SO₄²⁻, PO₄³⁻ and NO₃⁻) originating largely from the burning of wood and coal for residential heating in nearby villages in the surrounding area. The air in the caves with speleotherapy facilities should be monitored with respect to NTM, PM and anions to ensure a safe environment.

Inhalation of ZnO Nanoparticles: Splice Junction Expression and Alternative Splicing in Mice

Despite the wide application of nanomaterials, toxicity studies of nanoparticles (NP) are often limited to in vitro cell models, and the biological impact of NP exposure in mammals has not been thoroughly investigated. Zinc oxide (ZnO) NPs are commonly used in various consumer products. To evaluate the effects of the inhalation of ZnO NP in mice, we studied splice junction expression in the lungs as a proxy to gene expression changes analysis. Female ICR mice were treated with 6.46 × 104 and 1.93 × 106 NP/cm3 for 3 days and 3 months, respectively. An analysis of differential expression and alternative splicing events in 298 targets (splice junctions) of 68 genes involved in the processes relevant to the biological effects of ZnO NP was conducted using next-generation sequencing. Three days of exposure resulted in the upregulation of IL-6 and downregulation of BID, GSR, NF-kB2, PTGS2, SLC11A2, and TXNRD1 splice junction expression; 3 months of exposure increased the expression of splice junctions in ALDH3A1, APAF1, BID, CASP3, DHCR7, GCLC, GCLM, GSR, GSS, EHHADH, FAS, HMOX-1, IFNγ, NF-kB1, NQO-1, PTGS1, PTGS2, RAD51, RIPK2, SRXN1, TRAF6, and TXNRD1. Alternative splicing of TRAF6 and TXNRD1 was induced after 3 days of exposure to 1.93 × 106 NP/cm3. In summary, we observed changes of splice junction expression in genes involved in oxidative stress, apoptosis, immune response, inflammation, and DNA repair, as well as the induction of alternative splicing in genes associated with oxidative stress and inflammation. Our data indicate the potential negative biological effects of ZnO NP inhalation.

Leukocyte telomere length is not affected by long-term occupational exposure to nano metal oxides

The aim of this study was to ascertain whether long-term occupational exposure to nanoparticles would affect relative leukocyte telomere length (LrTL). We analysed occupational exposure to size-resolved aerosol particles, with special emphasis on nanoparticles at two workshops: i/ the production of nanocomposites containing metal oxides; ii/ laboratory to test experimental exposure of nano-CuO to rodents. Thirty five exposed researchers (age 39.5 ± 12.6 yr; exposure duration 6.0 ± 3.7 yr) and 43 controls (40.4 ± 10.5 yr) were examined. LrTL did not significantly (p=0.14) differ between the exposed researchers (0.92 ± 0.13) and controls (0.86 ± 0.15). In addition, no significant correlation (r=-0.22, p=0.22) was detected between the duration of occupational exposure and LrTL. The results remained non-significant after multiple adjustments for age, sex and smoking status. Our pilot results suggest that relative leukocyte telomere length is not affected by occupational exposure to nanoparticles.

A murine model of the effects of inhaled CuO nanoparticles on cells of innate and adaptive immunity - a kinetic study of a continuous three-month exposure

The inhalation or application of nanoparticles (NPs) has serious impacts on immunological reactivity. However, the effects of NPs on the immune system are influenced by numerous factors, which cause a high variability in the results. Here, mice were exposed to a three month continuous inhalation of copper oxide (CuO) NPs, and at different time intervals (3, 14, 42 and 93 days), the composition of cell populations of innate and adaptive immunity was evaluated in the spleen by flow cytometry. The ability of spleen cells from exposed and control mice to respond to stimulation with T- or B-cell mitogens by proliferation and by production of cytokines IL-2, IL-6, IL-10, IL-17 and IFN-γ was characterized. The results showed that the inhalation of CuO NPs predominantly affects the cells of innate immunity (changes in the proportion of eosinophils, neutrophils, macrophages and antigen-presenting cells) with a minimal effect on the percentage of T and B lymphocytes. However, the proliferative and secretory activity of T cells was already significantly enhanced after 3 days from the start of inhalation, decreased on day 14 and normalized at the later time intervals. There was no correlation between the impacts of NPs on the cells of innate and adaptive immunity. The results have shown that the inhalation of CuO NPs significantly alters the composition of cell populations of innate immunity and modulates the proliferation and production of cytokines by cells of the adaptive immune system. However, the immunomodulatory effects of inhaled NPs strongly depend on the time of inhalation.

Inhaled Cadmium Oxide Nanoparticles: Their in Vivo Fate and Effect on Target Organs

The increasing amount of heavy metals used in manufacturing equivalently increases hazards of environmental pollution by industrial products such as cadmium oxide (CdO) nanoparticles. Here, we aimed to unravel the CdO nanoparticle destiny upon their entry into lungs by inhalations, with the main focus on the ultrastructural changes that the nanoparticles may cause to tissues of the primary and secondary target organs. We indeed found the CdO nanoparticles to be transported from the lungs into secondary target organs by blood. In lungs, inhaled CdO nanoparticles caused significant alterations in parenchyma tissue including hyperemia, enlarged pulmonary septa, congested capillaries, alveolar emphysema and small areas of atelectasis. Nanoparticles were observed in the cytoplasm of cells lining bronchioles, in the alveolar spaces as well as inside the membranous pneumocytes and in phagosomes of lung macrophages. Nanoparticles even penetrated through the membrane into some organelles including mitochondria and they also accumulated in the cytoplasmic vesicles. In livers, inhalation caused periportal inflammation and local hepatic necrosis. Only minor changes such as diffusely thickened filtration membrane with intramembranous electron dense deposits were observed in kidney. Taken together, inhaled CdO nanoparticles not only accumulated in lungs but they were also transported to other organs causing serious damage at tissue as well as cellular level.

Aerosol Counterflow Two-Jets Unit for Continuous Measurement of the Soluble Fraction of Atmospheric Aerosols

A new type of aerosol collector employing a liquid at laboratory temperature for continuous sampling of atmospheric particles is described. The collector operates on the principle of a Venturi scrubber. Sampled air flows at high linear velocity through two Venturi nozzles "atomizing" the liquid to form two jets of a polydisperse aerosol of fine droplets situated against each other. Counterflow jets of droplets collide, and within this process, the aerosol particles are captured into dispersed liquid. Under optimum conditions (air flow rate of 5 L/min and water flow rate of 2 mL/min), aerosol particles down to 0.3 microm in diameter are quantitatively collected in the collector into deionized water while the collection efficiency of smaller particles decreases. There is very little loss of fine aerosol within the aerosol counterflow two-jets unit (ACTJU). Coupling of the aerosol collector with an annular diffusion denuder located upstream of the collector ensures an artifact-free sampling of atmospheric aerosols. Operation of the ACTJU in combination with on-line detection devices allows in situ automated analysis of water-soluble aerosol species (e.g., NO2-, NO3-)with high time resolution (as high as 1 s). Under the optimum conditions, the limit of detection for particulate nitrite and nitrate is 28 and 77 ng/m(3), respectively. The instrument is sufficiently rugged for its application at routine monitoring of aerosol composition in the real time.

A continuous-flow instrument for the determination of linear polyacrylamide stability

Alkaline hydrolysis of high-molecular-mass (10 MDa) linear polyacrylamide, a widely used replaceable sieving medium for the capillary electrophoresis of DNA fragments and proteins, was investigated. The release rate of ammonia, a product of amide group hydrolysis, was monitored by a high-sensitivity continuous-flow system. The experimental results show a rapid onset of hydrolysis at a temperature of 70 degrees C. While the degree of 1 h hydrolysis was evaluated to reach about 16% at 70 degrees C and pH 13, it drops to 5% at 50 degrees C and pH 12.5.