Andrea Caglieri

The Effect of Inhaled Chromium on Different Exhaled Breath Condensate Biomarkers among Chrome-Plating Workers

Chromium is corrosive, cytotoxic, and carcinogenic for humans and can induce acute and chronic lung tissue toxicity. The aim of this study was to investigate Cr levels in exhaled breath condensate (EBC) of workers exposed to Cr(VI) and to assess their relationship with biochemical changes in the airways by analyzing EBC biomarkers of oxidative stress, namely, hydrogen peroxide (H2O2) and malondialdehyde (MDA). EBC samples were collected from 24 chrome-plating workers employed in a chrome-plating plant both before and after the Friday work shift and before the work shift on the following Monday. Cr-EBC levels increased from the beginning (5.3 μg/L) to the end of Friday (6.4 μg/L) but were considerably lower on Monday morning (2.8 μg/L). A similar trend was observed for H2O2-EBC levels (which increased from 0.36 μM to 0.59 μM on Friday and were 0.19 μM on Monday morning) and MDA-EBC levels (which increased from 8.2 nM to 9.7 nM on Friday and were 6.6 nM on Monday). Cr-EBC levels correlated with those of H2O2-EBC (r = 0.54, p < 0.01) and MDA-EBC (r = 0.59, p < 0.01), as well as with urinary Cr levels (r = 0.25, p < 0.05). The results of this study demonstrate that EBC is a suitable matrix that can be used to investigate both Cr levels and biomarkers of free radical production sampling the epithelial-lining fluid of workers exposed to Cr(VI).

Low concentrations of the brominated flame retardants BDE-47 and BDE-99 induce synergistic oxidative stress-mediated neurotoxicity in human neuroblastoma cells.

Polybrominated diphenyl ether (PBDE) flame retardants have become widespread environmental contaminants. The highest body burden has been found in toddlers and infants, due to their exposure through breast milk and house dust, and the current concern for potential adverse health effects of PBDEs relates to their developmental neurotoxicity. The mechanisms underlying the neurotoxicity of PBDEs are largely not understood, though there is evidence that PBDEs may elicit oxidative stress. In this study, two different mathematical models were used to evaluate the interaction between BDE-47 and BDE-99 on viability of neuronal cells. The combined exposure to these compounds induced synergistic effects at concentrations of BDE-47 below its threshold doses, and in a wide range of BDE-99 concentrations below its IC(50). In contrast, at concentrations of BDE-47 near its IC(50) value, and in a wide range of BDE-99 concentrations, antagonistic effects were observed. The interactions observed on cell viability were confirmed by an assessment of induction of oxidative stress. The finding that co-exposure to BDE-47 and BDE-99 could induce synergistic neurotoxic effects, in particular at low doses of BDE-47, is of much toxicological interest, as humans are exposed to mixtures of PBDEs, most notably tetra- and penta-BDE congeners.

Influence of condensation temperature on selected exhaled breath parameters

BackgroundThe effects of changes in cooling temperature on biomarker levels in exhaled breath condensate have been little investigated. The aim of the study was to test the effect of condensation temperature on the parameters of exhaled breath condensate and the levels of selected biomarkers.MethodsExhaled breath condensate was collected from 24 healthy subjects at temperatures of -10, -5, 0 and +5 C degrees. Selected parameters (condensed volume and conductivity) and biomarkers (hydrogen peroxide, malondialdehyde) were measured.ResultsThere was a progressive increase in hydrogen peroxide and malondialdehyde concentrations, and condensate conductivity as the cooling temperature increased; total condensate volume increased as the cooling temperature decreased.ConclusionThe cooling temperature of exhaled breath condensate collection influenced selected biomarkers and potential normalizing factors (particularly conductivity) in different ways ex vivo. The temperature of exhaled breath condensate collection should be controlled and reported.

Heme oxygenase-1 expression in the left atrial myocardium of patients with chronic atrial fibrillation related to mitral valve disease: its regional relationship with structural remodeling.

Atrial fibrillation becomes a self-perpetuating arrhythmia as a consequence of electrophysiologic and structural remodeling involving the atrium. Oxidative stress may be a link between this rhythm disturbance and electrophysiologic remodeling. The aim of this study was to evaluate whether the heme oxygenase-1 (HO-1) marker of oxidative stress was more expressed in left atrial sites with stronger structural remodeling in patients affected by chronic atrial fibrillation (CAF) and mitral valve disease (MD). Myocardial samples were taken from the left atrial posterior wall (LAPW) and left atrial appendage (LAA) of 24 patients with CAF-MD in addition to 10 autopsy controls. The levels of HO-1 messenger RNA (mRNA) and HO-1 protein in each pathologic LAPW and LAA were quantified using reverse transcriptase polymerase chain reaction and enzyme-linked immunosorbent assay. Furthermore, light microscopy was used to morphometrically evaluate the differential myocyte and interstitial changes in the same CAF-MD LAPW and LAA samples. In controls, HO-1 protein was quantified using enzyme-linked immunosorbent assay. Unlike controls, patients with CAF-MD had higher levels of HO-1 mRNA and its protein product, expressed as LAPW/LAA ratios, in the LAPW (2.18 +/- 1.18, P < .0001, and 1.55 +/- 0.67, P < .005), and their LAPW also showed greater histologic changes in myocytolytic myocytes (15.1% +/- 3.1% versus 6.9% +/- 3.3%, P < .0001), interstitial fibrosis (8.2% +/- 2.2% versus 2.8% +/- 1.2%, P < .0001), and capillary density (816 +/- 120 number/mm(2) versus 1114 +/- 188 number/mm(2); P < .05). In addition, markers of oxidative stress were immunohistochemically studied with antinitrotyrosine and anti-iNOS antibodies. In patients with CAF-MD, the inducible enzyme HO-1 is more expressed in the left atrial areas that show greater structural remodeling. This finding strongly suggests a pathogenetic relationship between oxidative stress and the degree of histologic change.

Models of Neurotoxicity: Extrapolation of Benchmark Doses in Vitro

In risk assessment, no observed exposure level (NOAEL) and benchmark dose (BMD) are usually derived either from epidemiological studies in humans or from animal experiments. In many in vitro studies, concentration-effect/response curves have been analyzed using different mathematical models finalized to the identification of EC50. In the present article, we propose a model to fit dose-response curves in vitro. The BMD approach has been used to compare the cell viability (MIT assay) of different rat (C6 and PC12, glial and neuronal, respectively) and human cell lines (D384 and SK-N-MC, glial and neuronal, respectively) after 24-hour exposure to the following neurotoxic substances: manganese chloride (MnCl2), methyl-mercury (Me-Hg), and the enantiomers of styrene oxide (SO). For all rat and human cell lines, the potency of the examined compounds was: MnCl2 < S-SO < R-SO < Me-Hg. A preliminary comparison with in vivo toxicity data for these substances gave rise to consistent results. Whereas a reasonable agreement between in vitro and in vivo data has been found for Mn and styrene oxide, a wide scatter of LOAEL has been reported for Me-Hg and these appear to be either much higher or lower than the BMD for the MIT assay we observed in vitro.

Synergistic interactions between PBDEs and PCBs in human neuroblastoma cells

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) are ubiquitous environmental pollutants. Exposure to these chemicals has been associated with developmental neurotoxicity, endocrine dysfunction, and reproductive disorders. Humans and wildlife are generally exposed to a mixture of these environmental pollutants, highlighting the need to evaluate the potential effects of combined exposures. In this study, we investigated the cytotoxic effects of the combined exposure to two PBDEs and two PCBs in a human neuronal cell line. 2,2′,4,4′‐Tetrabromodiphenyl ether, 2,2′,4,4′,5‐pentabromodiphenyl ether, PCB‐126 (3,3′,4,4′,5‐pentachlorobiphenyl; a dioxin‐like PCB), and PCB‐153 (2,2′,4,4′,5,5′‐hexachlorobiphenyl; a non‐dioxin‐like PCB) were chosen, because their concentrations are among the highest in human tissues and the environment. The results suggest that the nature of interactions is related to the PCB structure. Mixtures of PCB‐153 and both PBDEs had a prevalently synergistic effect. In contrast, mixtures of each PBDE congener with PCB‐126 showed additive effects at threshold concentrations, and synergistic effects at higher concentrations. These results emphasize the concept that the toxicity of xenobiotics may be affected by possible interactions, which may be of significance given the common coexposures to multiple contaminants.

Single step determination of PCB 126 and 153 in rat tissues by using solid phase microextraction/gas chromatography-mass spectrometry : Comparison with solid phase extraction and liquid/liquid extraction

A simple and reliable solid phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS) method was developed for the single-step determination of PCBs 126 and 153 in rat brain and serum, using liquid/liquid and solid phase extraction (SPE) as reference techniques. The multi-factor categorical experimental design used to study simultaneously the main parameters and their interactions affecting the efficiency of the method, showed that the use of an 85mum PA exposed at 100 degrees C for 40min was the optimum sampling condition for both PCBs. SPME was then validated by studying its linear dynamic (over two orders of magnitude), limits of detection (brain: 2ng/g, serum: 0.2ng/g) and analytical precision that was within 9% for SPME in both brain and serum. Finally, the method was used to determine the brain and blood target dose in mothers and pups after oral exposure of the mothers.

Development and set-up of a portable device to monitor airway exhalation and deposition of particulate matter.

The aim of this study was to assess and monitor airway exhalation and deposition of particulate matter (PM). After standardizing inspiratory/expiratory flow and volumes, a novel device was tested on a group of 20 volunteers and in a field study on workers exposed to cristobalite. Both male and female subjects showed a higher percentage of deposition in the 0.5 μm channel than in the 0.3 μm channel on a laser particle counter, but it was higher in the males because of their higher exhaled lung volumes. The device was tested on a wider range of particles (0.3–0.5–1.0–2.5 μm) in the cristobalite productive division. The device has low intrasubject variability and good reproducibility, with geometric mean of %CV < 5%. Such a measure can be used to assess individual susceptibility to PM, making repeated measures in different environments, and examining the persistence of particles in the airways after a period in polluted environments.

Collecting Exhaled Breath Condensate (EBC) with Two Condensers in Series: A Promising Technique for Studying the Mechanisms of EBC Formation, and the Volatility of Selected Biomarkers

Exhaled breath condensate (EBC) consists mainly of water, but also contains semivolatile and nonvolatile compounds. The aim of this study was to develop a system in which two condensers are simultaneously used in series to clarify the mechanisms of EBC condensation. Two aliquots of EBC (EBC1 and EBC2) were collected from 20 asymptomatic smokers and 20 healthy young nonsmokers using a specifically designed device having two condensers in series in which total volume, hydrogen peroxide (H(2)O(2)), ammonium (NH(4)(+)), and conductivity before and after lyophilization were measured. Water, NH(4)(+) levels and conductivity before lyophilization were significantly lower in the EBC2 than in the EBC1 of smokers and nonsmokers; the contrary was true for H(2)O(2) levels. Almost all nonvolatile salts were collected in the first condenser, because more than 50% of postlyophilization conductivity was below the detection limit in EBC2. The recovery of volatile molecules and their derivatives (water and NH(4)(+)) was partial in the first condenser, but appreciable amounts of both were measured in the second; however, the condenser immediately in contact with exhaled air was more efficient in terms of water, NH(4)(+) and conductivity before lyophilization. On the contrary, nonvolatile ions (conductivity after lyophilization) were mainly collected in the first condenser. Finally, the behavior of H(2)O(2) cannot be explained on the basis of its chemical and physical properties, and the most probable explanation is that some was byproduced by a radical reaction in the gas phase or during the condensation process in water.