[Show abstract][Hide abstract] ABSTRACT: Inhalation is the main pathway of ZnO exposure in the occupational environment but only few studies
have addressed toxic effects after pulmonary exposure to ZnO nanoparticles (NP). Here we present results
from three studies of pulmonary exposure and toxicity of ZnO NP in mice. The studies were prematurely
terminated because interim results unexpectedly showed severe pulmonary toxicity. High
bolus doses of ZnO NP (25 up to 100 mg; �1.4 mg/kg) were clearly associated with a dose dependent
mortality in the mice. Lower doses (�6 mg; �0.3 mg/kg) elicited acute toxicity in terms of reduced weight
gain, desquamation of epithelial cells with concomitantly increased barrier permeability of the alveolar/
blood as well as DNA damage. Oxidative stress was shown via a strong increase in lipid peroxidation and
reduced glutathione in the pulmonary tissue. Two months post-exposure revealed no obvious toxicity for
12.5 and 25 mg on a range of parameters. However, mice that survived a dose (50 mg; 2.7 mg/kg) had an
increased pulmonary collagen accumulation (fibrosis) at a similar level as a high bolus dose of crystalline
silica. The recovery from these toxicological effects appeared dose-dependent. The results indicate that
alveolar deposition of ZnO NP may cause significant adverse health effects.
Food and Chemical Toxicology 08/2015; Food Chem. Toxicol.. DOI:10.1016/j.fct.2015.08.008 · 2.90 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Uptake of nanoparticles by endothelial cells is dependent on shear stress adaptation and flow exposure conditions. Adaptation of primary human umbilical vein endothelial cells (HUVECs) to shear stress for 24 h was associated with reduced internalisation of unmodified 80 nm spherical gold nanoparticles (AuNPs) (mean hydrodynamic size of 99 nm in culture medium) after exposure in flow condition compared with cells that were cultured and exposed in static condition. In static condition, targeting of 80 nm AuNPs conjugated with antibodies against the intracellular adhesion molecule 1 (ICAM-1) (mean hydrodynamic size of 109 nm in culture medium) markedly increased the internalisation of AuNPs in HUVECs that were activated with tumour necrosis factor (TNF), a treatment that markedly increased the surface expression of ICAM-1. Shear stress-adapted and TNF-activated HUVECs, which were exposed in flow condition, had higher association with anti-ICAM-1 AuNPs than cells that were not TNF-activated or exposed to particles in static condition. Hence, shear stress adaptation reduces uptake of unmodified AuNPs and increases the association between anti-ICAM-1 AuNPs and TNF-activated HUVECs.
[Show abstract][Hide abstract] ABSTRACT: Engineered nanomaterials (NMs) offer great technological advantages but their risks to human health are still not fully understood. An increasing body of evidence suggests that some NMs are capable of distributing from the site of exposure to a number of secondary organs. The research into the toxicity posed by the NMs in these secondary organs is expanding due to the realisation that some materials may reach and accumulate in these target sites. The translocation to secondary organs includes, but is not limited to, the hepatic, central nervous, cardiovascular and renal systems. Current data indicates that pulmonary exposure is associated with low (inhalation route–0.00001–1% of total applied dose–24 h) translocation of virtually insoluble NMs such as iridium, carbon black, gold and polystyrene, while slightly higher translocation has been observed for NMs with either slow (e.g. silver, cerium dioxide and quantum dots) or fast (e.g. zinc oxide) solubility. The translocation of NMs following intratracheal, intranasal and pharyngeal aspiration is higher (up to 10% of administered dose), however the relevance of these routes for risk assessment is questionable. Uptake of the materials from the gastrointestinal tract seems to follow the same pattern as inhalation translocation, whereas the dermal uptake of NMs is generally reported to be low. The toxicological effects in secondary organs include oxidative stress, inflammation, cytotoxicity and dysfunction of cellular and physiological processes. For toxicological and risk evaluation, further information on the toxicokinetics and persistence of NMs is crucial. The overall aim of this review is to outline the data currently available in the literature on the biokinetics, accumulation, toxicity and eventual fate of NMs in order to assess the potential risks posed by NMs to secondary organs.
Critical Reviews in Toxicology 07/2015; DOI:10.3109/10408444.2015.1058747 · 5.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Free palmitic acid (PA) is a potential pro-atherogenic stimulus that may aggravate particle-mediated cardiovascular health effects. We hypothesized that the presence of PA can aggravate oxidative stress and endothelial activation induced by multi-walled carbon nanotube (MWCNT) exposure in vitro. We investigated the interaction between direct exposure to MWCNTs and PA on THP-1 monocyte adhesion to human umbilical vein endothelial cells (HUVECs), as well as on indirect exposure in an alveolar-endothelial co-culture model with A549 cells and THP-1-derived macrophages exposed in inserts and the effect measured in the lower chamber on HUVECs and THP-1 cells. The exposure to MWCNTs, including a short (NM400) and long (NM402) type of entangled fibers, was associated with elevated levels of reactive oxygen species as well as a decrease in the intracellular glutathione concentration in HUVEC and A549 monocultures. Both effects were found to be independent of the presence of PA. MWCNT exposure significantly increased THP-1 monocyte adhesion to HUVECs, and co-exposure to PA aggravated the NM400-mediated adhesion but decreased the NM402-mediated adhesion. For the co-cultures, the exposure of A549 cells did not promote THP-1 adhesion to HUVECs in the lower chamber. When THP-1 macrophages were present on the cell culture inserts, there was a modest increase in the adhesion and an increase in interleukin-6 and interleukin-8 levels in the lower chamber whereas no tumor necrosis factor was detected. Overall, this study showed that direct exposure of HUVECs to MWCNTs was associated with oxidative stress and monocyte adhesion and the presence of PA increased the adhesion when exposed to NM400.
[Show abstract][Hide abstract] ABSTRACT: Metabolic syndrome is associated with increased risk of cardiovascular disease, which could be related to oxidative stress. Here, we investigated the associations between hepatic oxidative stress and vascular function in pressurized mesenteric arteries from lean and obese Zucker rats at 14, 24 and 37 weeks of age. Obese Zucker rats had more hepatic fat accumulation than their lean counterparts. Nevertheless, the obese rats had unaltered age-related level of hepatic oxidatively damaged DNA in terms of formamidopyrimidine DNA glycosylase (FPG) or human oxoguanine DNA glycosylase (hOGG1) sensitive sites as measured by the comet assay. There were decreasing levels of oxidatively damaged DNA with age in the liver of lean rats, which occurred concurrently with increased expression of Ogg1. The 37 week old lean rats also had higher expression level of Hmox1 and elevated levels of DNA strand breaks in the liver. Still, both strain of rats had increased protein level of HMOX-1 in the liver at 37 weeks. The external and lumen diameters of mesenteric arteries increased with age in obese Zucker rats with no change in media cross-sectional area, indicating outward re-modelling without hypertrophy of the vascular wall. There was increased maximal response to acetylcholine-mediated endothelium-dependent vasodilatation in both strains of rats. Collectively, the results indicate that obese Zucker rats only displayed a modest mesenteric vascular dysfunction, with no increase in hepatic oxidative stress-generated DNA damage despite substantial hepatic steatosis.
PLoS ONE 03/2015; 10(3):e0118773. DOI:10.1371/journal.pone.0118773 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Gold nanoparticles (AuNPs) are relevant in nanomedicine for drug delivery in the vascular system, where endothelial cells are first point of contact. We investigated the uptake of 80 nm AuNPs in primary human umbilical vein endothelial cells (HUVECs) by flow cytometry, 3D confocal microscopy, nano-scale 3D-imaging using focused ion beam - scanning electron microscopy (FIB/SEM), and single particle inductively coupled plasma - mass spectrometry (spICP-MS). HUVECs were cultured for 3 or 24 h in medium with AuNPs in a concentration range of 1.25 – 10 µg/ml. There was a concentration-dependent increase of AuNP inside cells measured by flow cytometry, spICP-MS and 3D confocal microscopy. The latter also showed that AuNPs were located in the cytosol. This was supported by FIB/SEM, showing that AuNPs were located in membrane enclosures in the cytoplasm as single particles or agglomerates of 2-3 or more particles. Pre-treatment with chlorpromazine inhibited the AuNP uptake in HUVECs, indicating that internalisation occurred mainly by clathrin-mediated endocytosis. Cell activation by exposure to tumour necrosis factor or lipopolysaccharide had slight and no effect on the uptake of AuNPs, respectively. The AuNP exposure did not influence cell cytotoxicity, whereas the intracellular reactive oxygen species production was slightly increased. In conclusion, uptake of AuNPs by endothelial cells can be addressed quantitatively by several methods with high throughput and/or high specificity. Uptake of AuNPs in HUVECs occurred by mainly clathrin-mediated endocytosis and trafficking to membrane enclosures in the form of single and agglomerates of 2-3 particles.
Toxicology Research 03/2015; 4(3):655-666. DOI:10.1039/C4TX00061G · 3.98 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To explore associations of exposure to ambient and indoor air particulate and bio-aerosol pollutants with cardiovascular and respiratory disease markers, we utilized seven repeated measurements from 48 elderly subjects participating in a 4-week home air filtration study. Microvascular function (MVF), lung function, blood leukocyte counts, monocyte adhesion molecule expression, C-reactive protein, Clara cell protein (CC16) and surfactant protein-D (SPD) were examined in relation to exposure preceding each measurement. Exposure assessment included 48-h urban background monitoring of PM10, PM2.5 and particle number concentration (PNC), weekly measurements of PM2.5 in living- and bedroom, 24-h measurements of indoor PNC three times, and bio-aerosol components in settled dust on a 2-week basis. Statistically significant inverse associations included: MVF with outdoor PNC; granulocyte counts with PM2.5; CD31 expression with dust fungi; SPD with dust endotoxin. Significant positive associations included: MVF with dust bacteria; monocyte expression of CD11 with PM2.5 in the bedroom and dust bacteria and endotoxin, CD31 expression with dust serine protease; serum CC16 with dust NAGase. Multiple comparisons demand cautious interpretation of results, which suggest that outdoor PNC have adverse effects on MVF, and outdoor and indoor PM2.5 and bio-aerosols are associated with markers of inflammation and lung cell integrity.
International journal of environmental research and public health 02/2015; 12(2):1667-1686. DOI:10.3390/ijerph120201667 · 2.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Blueberries are a rich source of anthocyanins (ACNs) and phenolic acids (PA), which are hypothesized to protect against development of atherosclerosis. The present study examined the effect of an ACN- and PA-rich fractions, obtained from a wild blueberry powder, on the capacity to counteract lipid accumulation in macrophages derived from monocytic THP-1 cells. In addition, we tested the capacity of pure ACNs and their metabolites to alter lipid accumulation.
THP-1-derived macrophages were incubated with fatty acids (500 μM oleic/palmitic acid, 2:1 ratio) and different concentrations (from 0.05 to 10 μg mL(-1)) of ACN- and PA-rich fractions, pure ACN standards (malvidin, delphinidin and cyanidin 3-glucoside), and metabolites (syringic, gallic and protocatechuic acids). Lipid accumulation was quantified with the fluorescent dye Nile red.
Lipid accumulation was reduced at all concentrations of the ACN-rich fraction tested with a maximum reduction at 10 μg mL(-1) (-27.4 %; p < 0.0001). The PA-rich fraction significantly reduced the lipid accumulation only at the low concentrations from 0.05 µg mL(-1) to 0.3 µg mL(-1), with respect to the control with fatty acids. Supplementation with pure ACN compounds (malvidin and delphinidin-3-glucoside and its metabolic products (syringic and gallic acid)) reduced lipid accumulation especially at the low concentrations, while no significant effect was observed after cyanidin-3-glucoside and protocatechuic acid supplementation.
The results demonstrated a potential role of both the ACN- and PA-rich fractions and single compounds in the lipid accumulation also at concentrations close to that achievable in vivo.
European Journal of Nutrition 01/2015; DOI:10.1007/s00394-015-0835-z · 3.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Aging is associated with oxidative stress-generated damage to DNA and this could be related to metabolic disturbances. This study investigated the association between levels of oxidatively damaged DNA in peripheral blood mononuclear cells (PBMCs) and metabolic risk factors in 1,019 subjects, aged 18-93 years. DNA damage was analyzed as strand breaks by the comet assay and levels of formamidopyrimidine (FPG-) and human 8-oxoguanine DNA glycosylase 1 (hOGG1)-sensitive sites There was an association between age and levels of FPG-sensitive sites for women, but not for men. The same tendency was observed for the level of hOGG1-sensitive sites, whereas there was no association with the level of strand breaks. The effect of age on oxidatively damaged DNA in women disappeared in multivariate models, which showed robust positive associations between DNA damage and plasma levels of triglycerides, cholesterol and glycosylated hemoglobin (HbA1c). In the group of men, there were significant positive associations between alcohol intake, HbA1c and FPG-sensitive sites in multivariate analysis. The levels of metabolic risk factors were positively associated with age, yet only few subjects fulfilled all metabolic syndrome criteria. In summary, positive associations between age and levels of oxidatively damaged DNA appeared mediated by age-related increases in metabolic risk factors.
[Show abstract][Hide abstract] ABSTRACT: Exposure to ambient air particulate matter (PM) has been linked to decline in pulmonary function and cardiovascular events possibly through inflammation. Little is known about individual exposure to ultrafine particles (UFP) inside and outside modern homes and associated health-related effects.
Associations between vascular and lung function, inflammation markers and exposure in terms of particle number concentration (PNC; d = 10-300 nm) were studied in a cross-sectional design with personal and home indoor monitoring in the Western Copenhagen Area, Denmark. During 48-h, PNC and PM2.5 were monitored in living rooms of 60 homes with 81 non-smoking subjects (30-75 years old), 59 of whom carried personal monitors both when at home and away from home. We measured lung function in terms of the FEV1/FVC ratio, microvascular function (MVF) and pulse amplitude by digital artery tonometry, blood pressure and biomarkers of inflammation including C-reactive protein, and leukocyte counts with subdivision in neutrophils, eosinophils, monocytes, and lymphocytes in blood.
PNC from personal and stationary home monitoring showed weak correlation (r = 0.15, p = 0.24). Personal UFP exposure away from home was significantly inversely associated with MVF (1.3% decline per interquartile range, 95% confidence interval: 0.1-2.5%) and pulse amplitude and positively associated with leukocyte and neutrophil counts. The leukocyte and neutrophil counts were also positively and pulse amplitude negatively associated with total personal PNC. Indoor PNC and PM2.5 showed positive association with blood pressure and inverse association with eosinophil counts.
The inverse association between personal exposure away from home and MVF is consistent with adverse health effects of UFP from sources outside the home and might be related to increased inflammation indicated by leukocyte counts, whereas UFP from sources in the home could have less effect.
Environmental Health 12/2014; 13(1):112. DOI:10.1186/1476-069X-13-112 · 3.37 Impact Factor