FA Exposure Research Articles

Abstract 17126: Role of Aldehydes, Transient Receptor Potential Ankyrin 1, and Catecholamines in Electronic Cigarette-Induced Endothelial Dysfunction in Mice

Although Electronic Nicotine Delivery Systems (ENDS)-derived aerosols induce endothelial dysfunction (ED), the mechanisms and constituents responsible for ED are unknown. Because ENDS use propylene glycol and vegetable glycerin (PG:VG) that thermally decompose into aldehydes, we hypothesized that acrolein and formaldehyde stimulate ED via the sensory transient receptor potential ankyrin-1 (TRPA1) receptor and the autonomic nervous system (ANS). To test this, female wild-type (WT) and TRPA1-null mice were exposed to either filtered air, PG:VG-derived aerosol, acrolein (AC; 1 ppm), or formaldehyde (FA, 5 ppm). Biomarkers of exposure (AC: 3HPMA; FA: 4TCA) and of harm (aortic ED; urinary catecholamines) were measured. The PG:VG and AC exposures significantly increased urinary 3HPMA levels; and the PG:VG and FA exposures significantly increased urinary 4TCA levels vs air controls. Both PG:VG and FA exposures (6h/d x 4d) in WT mice led to aortic ED (-64.6±3.8; –66.7±5.5 % ACh, respectively) vs air control (-81.5±1.5 % ACh); yet AC exposure did not induce ED (-76±2.9 % ACh). Exposures in TRPA1-null mice to PG:VG, AC, or FA did not lead to ED (-93.0±3.6; –82.8±3.1; -86.6±2.8 % ACh; respectively). As an index of ANS activation and a potential mediator of ED, urinary catecholamines (dopamine, DA; norepinephrine, NE; epinephrine, EPI; serotonin, 5HT) and metabolites were measured by UPLC-MS/MS in early (0-3h) and late (3-18h) post-exposure (PE) samples. In WT mice, PG:VG significantly increased early PE urine levels of NE (and two NE metabolites; +1.5-2.5x), DA metabolite (+1.5x), but not EPI nor 5HT; FA exposure increased DA (+3x), EPI (+2.5x), NE and NE metabolites (+1.2-2.5x), 5HT and 5HT metabolite (+2.5x) only in late PE; while AC exposure decreased early PE DA (-73%) and 5HT (-42%) levels. In TRPA1-null mice, PG:VG and AC exposures increased early PE levels of NE (+2x) and depressed EPI and 5HT levels (-40%); whereas FA exposure increased NE (+2x), EPI (+4x), and 5HT (+1.5) levels in late PE. Aldehydes induce ED through time-dependent mechanisms mediated in part by TRPA1 activation and ANS stimulation. These data indicate that ENDS use may increase cardiovascular disease risk via aldehydes generated by PG:VG independent of nicotine and flavorants.

Ferulic Acid Mitigates Growth and Invasion of Esophageal Squamous Cell Carcinoma through Inducing Ferroptotic Cell Death.

Objective Ferroptosis is an iron- and ROS-dependent form of cell death initiated by lipid peroxidation. The rapidly developing study of ferroptosis has facilitated its application in cancer therapeutics. The current study is aimed at investigating the functional property of ferulic acid (FA, a phenolic acid substance) on inducing ferroptosis in antiesophageal squamous cell carcinoma (ESCC). Methods ESCC cells were administrated with gradient doses of FA or with ferroptosis inhibitor deferoxamine. Cellular growth was measured with CCK-8 and colony formation experiments. LDH, caspase-3, MDA, SOD, GSH, and iron were assayed with corresponding kits. Apoptotic level was evaluated through Annexin V-FITC apoptosis staining, with migration and invasion utilizing Transwell assays. Through quantitative RT-PCR, angiogenesis-relevant genes VEGFA and PDGFB were detected. ROS generation was measured via DCFH-DA probe. Immunoblotting was conducted for monitoring ACSL4, SLC7A11, HO-1, and GPX4. Results FA administration observably mitigated cellular viability and colony formation capacity and motivated LDH release, caspase-3 activity, and apoptosis in EC-1 and TE-4 cells. In addition, migration and invasion together with angiogenesis of ESCC cells were restraint by FA. FA exposure led to the increase of MDA content, ROS production, and iron load as well as the reduction of SOD activity and GSH content. Also, FA augmented the activities of ACSL4 and HO-1, with lessening SLC7A11 and GPX4. Nonetheless, deferoxamine restrained the effect of FA on ESCC ferroptosis. Conclusion Altogether, FA may act as a ferroptosis inducer and thus attenuates cell growth and invasion of ESCC, which boosts the clinical application of FA in ESCC therapeutics.

Toxic effects of formaldehyde and the protective effect of docosahexaenoic acid in Drosophila

Formaldehyde (FA) is a commercially important chemical applied in industry and scientific research. However, FA has a distinct impact on learning and memory. Although the mechanisms of FA toxicity have been well studied, additional research is required to establish the mechanisms of neuroprotection in cases of FA exposure. Docosahexaenoic acid (DHA) is a polyunsaturated fatty acid with a variety of health benefits, including the enhancement of learning and memory. In this study, we investigated the neuroprotective effects of DHA in Drosophila melanogaster that had ingested FA. Our data suggested that DHA enhanced reproductive processes, leading to an increase in the number of eggs, larvae, and adults. Surprisingly, we found that DHA had a mild protective effect against FA-induced impairments in learning and memory.

Cytogenetic effects among workers exposed to formaldehyde. The possible role of some polymorphisms

Abstract Background Formaldehyde (FA) is a human carcinogen. It is commonly used in diluted form as formalin. The purpose of this work was to evaluate the frequencies of chromosomal aberrations (CAs) and sister chromatid exchanges (SCEs) as a consequence of the exposure to FA in a hospital setting, taking into account the role of some polymorphisms in developing genotoxic damage. Methods CAs and SCEs assays were performed on peripheral blood lymphocytes of 57 pathologists enrolled in Turin hospitals (Italy) and 48 unexposed enrolled as controls. All subjects were genotyped for CYP1A1 exon 7 (A>G), CYP1A1*2A (T>C), CYP2C19*2 (G>A), GSTT1 (Positive/Null), GSTM1 (Positive/null), GSTP1 (A>G), XRCC1 (G399A), XRCC1 (C194T), XRCC1 (A280G), XPD (A751C), XPC exon 15 (A939C), XPC exon 9 (C499T), TNFα -308 (G>A), IL10 -1082 (G>A), IL10 -819 (C>T) and IL6 -174 (G>C) gene polymorphisms. Due to the little number of recessive homozygotes, we compared the dominant genotype with the combined group of heterozygotes and recessive homozygotes. Results Among pathologists, the mean value of personal air-FA was 64.2 µg/m3, mean significantly higher (p = 0.000) than controls (19.1 µg/m3). Similarly, pathologists showed significantly higher values of SCEs (p = 0.009) and CAs (p = 0.000) with respect to controls. In the same group, CYP2C19*2 (p = 0.011), XRCC1 (G399A) (p = 0.007), and IL10 (-1082) (p = 0.042) gene polymorphisms influenced the CAS levels, as well as those of CYP1A1 exon 7 (p = 0.010), XPD A751C (p = 0.002), XPC C499T (p = 0.040), and IL10 (-819) (p = 0.005) the levels of SCEs. In control group, CAs resulted significantly lower in CYP1A1 exon 7 dominant homozygotes (p = 0.001). Conclusions Our study confirms the role of FA as an inductor of genotoxicity, even when, daily, workers are exposed to low FA levels. Some genetic polymorphisms seem to have an influence in modulating the effect of FA exposure, highlighting, in occupational health studies, the role of the individual susceptibility. Key messages FA exposure is confirmed to be a genotoxicity inductor even at low concentrations. Some genetic polymorphisms seem to have a role in the modulation of FA exposure-related damage.

Four weeks of environmentally relevant second hand smoke exposure decreased neuronal excitability of cardiac vagal neurons in the dorsal motor nucleus of vagus

BACKGROUNDSecond hand smoke (SHS), a main indoor air pollutant, is a significant risk factor for cardiovascular morbidity and mortality. We previously showed that exposure to SHS, for as short as four weeks, significantly reduced heart rate variability (HRV), suggesting a decreased vagal regulation of the heart. We further showed that, in cardiac vagal neurons in the nucleus ambiguus (NA), SHS exposure significantly reduced spiking response to depolarizing current injections and increased current‐ and voltage‐threshold for action potential generation. However, we have no information on the effects of SHS exposure on cardiac vagal neurons in the dorsal motor nucleus of vagus (DMNV). Here, we sought to test the hypothesis that SHS exposure decreases neuronal excitability of cardiac vagal neurons in the DMNV.METHODSSeven‐week old male C57BL/6J mice underwent surgeries to retrograde label cardiac vagal neurons by applying a fluorescent dye (DiI) to the sinoatrial node. Two weeks after surgery, mice were randomly assigned to either filtered air‐ (FA, n = 14) or SHS‐exposed (n = 16) group. The SHS exposure (6 hr/d, 5 d/wk) was set at a level that is similar to that of a smoky bar (3 mg/m3). After four weeks of FA or SHS exposure, whole‐cell current clamp recordings in brainstem slices were performed on anatomically identified cardiac vagal neurons in the DMNV with fluorescent labeling.RESULTSDMNV cardiac vagal neurons from the SHS‐exposed group were significantly more hyperpolarized than the FA control group (−53.3 ± 0.9 mV vs. −55.7 ± 0.7 mV, FA vs. SHS respectively, p < 0.05). Four weeks of SHS exposure also significantly decreased neuronal spontaneous spiking activity at a holding potential of −45 mV (1.6 ± 0.4 Hz vs. 0.8 ± 0.2 Hz, FA vs. SHS respectively, p < 0.05). The decreased spontaneous activity was not associated with the spiking response to depolarizing current injections from a holding potential of −60 mV, current and voltage threshold for action potential generation, action potential peak and afterhyperpolarization. Furthermore, there was no significant difference in the neuronal input‐output relationship of DMNV cardiac vagal neurons between FA control and SHS‐exposed groups, suggesting an unchanged dynamic responsiveness to stimuli.CONCLUSIONSFour weeks exposure to environmentally relevant level of SHS decreased neuronal excitability of cardiac vagal neurons in a region‐dependent manner – reduced resting membrane potential and spontaneous spiking activity in the DMNV and reduced spiking response to depolarizing current injections and increased threshold for action potential generation in the NA.Support or Funding InformationFunding: R01 ES025229

Learning and memory impairment of mice caused by gaseous formaldehyde

In order to study the e of formaldehyde exposure on learning and memory ability of mice. We used Kun Ming (KM) mice to demonstrate the neurotoxic effects of FA, and Balb/c mice to explore the neurobiological mechanism. The Morris water maze (MWM) test showed that the exposure of gaseous formaldehyde could cause spatial learning and memory impairment in mice. H & E staining showed that in the 3.0 mg/m3 formaldehyde exposed group, the arrangement of pyramidal cells in CA1 area of mouse hippocampus was loose and disordered, the cell morphology was swollen and deformed, and the apical dendrites were shortened or even disappeared. Biochemical indicators revealed high doses of FA exposure could cause oxidative damage in brain. Compared with the control group, there were significant differences in the levels of ROS, MDA, GSH and 8-OHDG in the 3.0 mg/m3 group (P < 0.01), also the monoamine neurotransmitters content and the content of TNF-α, IL-1β and Caspase-3 (P < 0.01). Furthermore, the concentrations of cAMP, cGMP, NO and the activity of NOS in the cerebral cortex, hippocampus and brain stem after high doses of FA exposure were significantly different from those in the control group, indicating that FA exposure could interfere with the transduction of NO/cGMP signaling pathway. The results showed that FA could induce cognitive deficits and this extended investigation found that the toxicity of FA to the mouse nervous system is related to the NO/cGMP and cAMP signaling pathways.

Differential Expression of miRNAs in the Hippocampi of Offspring Rats Exposed to Fluorine Combined with Aluminum during the Embryonic Stage and into Adulthood.

A previous study from our team found that continuous exposure to fluorine combined with aluminum (FA) impaired the neurobehavioral reflexes, spatial learning, and memory of offspring rats. To date, the specific mechanisms for these changes are unclear. Here, high-throughput sequencing was utilized to analyze the microRNA (miRNA) profile of the hippocampi in the offspring of rats exposed to FA during the embryonic stage and into adulthood through tap water supplemented with NaF and AlCl3 at concentrations of (0, 0); (60, 600); (120, 600); and (240, 600)mg/L, respectively. qRT-PCR was performed to validate the reliability of the sequence data. Twenty differentially expressed miRNAs were selected for further analysis using bioinformatics tools. Several genes related to neuromodulation were found to be regulated by miR-10a-5p, miR-34b-5p, and miR-182, which might be harmful to normal nerve function. The protein levels of brain-derived neurotrophic factor (BDNF) and tyrosine receptor kinase B (TrkB) in hippocampus were markedly downregulated. These data suggest that miR-10a-5p, miR-34b-5p, and miR-182 and BDNF-TrkB signaling pathway are involved in mechanisms of hippocampal damage in the offspring of rats exposed to FA. HIGHLIGHTS: • Multiple miRNAs were significantly differentially expressed in offspring rat hippocampus after fluorine combined with aluminum (FA) exposure. • Twenty differentially expressed miRNAs might mediate FA-induced developmental neurotoxicity. • MiR-10a-5p, miR-34b-5p, and miR-182 were closely related to neurotoxic signaling of FA. • The BDNF-TrkB learning and memory-associated pathway was downregulated in the hippocampus after FA exposure.

Improving Tumor Specificity and Anticancer Activity of Dasatinib by Dual-Targeted Polymeric Micelles.

To improve tumor targetability and drug efficacy and decrease drug resistance of dasatinib (DSB), the multifunctional micellar nanoparticles that combined the matrix metalloproteinase 2 (MMP2)-sensitive tumor (site) targeting with folate receptor-mediated tumor (cell) targeting were developed. Two major functional polymers, polyethylene glycol (5000 Da)-MMP2-sensitive peptide-phosphoethanolamine (PEG5k-pp-PE) and folic acid-polyethylene glycol (2000 Da)-phosphoethanolamine (FA-PEG2k-PE), were synthesized to construct the dual-targeted micellar nanoparticles (MMP/FR micelles). In the absence of MMP2, the FA was shielded by PEG5k and the MMP/FR micelles showed low bioactivity. In the presence of MMP2, the nanoparticulate structure, stability, and cargo release profile of the MMP/FR micelles were not significantly affected, however, the MMP2-mediated PEG5k deshielding and FA exposure remarkably increased the cellular uptake and anticancer activity of the micelles in the MMP2 and FR expressing (MMP2+/FR+) cells, including multidrug resistant (MDR) cancer cells, rather than the MMP2- and FR- cells. In the 3D MDR tumor spheroids, the significant MMP2-dependent tissue penetration, uptake and cytotoxicity of the MMP/FR micelles were also observed. Furthermore, in the in vivo biodistribution study, the MMP2 and FR dual targeting strategy could significantly prolong the systemic circulation, decrease the nonspecific distribution in nontumor tissues, and increase the tumor accumulation of the polymeric micelles in a melanoma xenograft mouse model. The MMP2-sensitive FR-targeted micelles might have great potential as a tumor-targeted platform for delivery of molecular targeted therapeutics.

Photobiomodulation Therapy Decreases Oxidative Stress in the Lung Tissue after Formaldehyde Exposure: Role of Oxidant/Antioxidant Enzymes.

Formaldehyde is ubiquitous pollutant that induces oxidative stress in the lung. Several lung diseases have been associated with oxidative stress and their control is necessary. Photobiomodulation therapy (PBMT) has been highlighted as a promissory treatment, but its mechanisms need to be better investigated. Our objective was to evaluate the effects of PBMT on the oxidative stress generated by FA exposure. Male Wistar rats were submitted to FA exposure of 1% or vehicle (3 days) and treated or not with PBMT (1 and 5 h after each FA exposure). Rats treated only with laser were used as control. Twenty-four hours after the last FA exposure, we analyzed the effects of PBMT on the generation of nitrites and hydrogen peroxide, oxidative burst, glutathione reductase, peroxidase, S-transferase enzyme activities, the gene expression of nitric oxide, cyclooxygenase, superoxide dismutase, the catalase enzyme, and heme oxygenase-1. PBMT reduced the generation of nitrites and hydrogen peroxide and increased oxidative burst in the lung cells. A decreased level of oxidant enzymes was observed which were concomitantly related to an increased level of antioxidants. This study provides new information about the antioxidant mechanisms of PBMT in the lung and might constitute an important tool for lung disease treatment.

High dose of formaldehyde exposure during pregnancy increases neutrophils lung influx evoked by ovalbumin in the offspring

Considering that asthma might have their onset in the intrauterine life and the exposure to FA during pregnancy interferes in the immune system of offspring, here we hypothesized that high dose of FA exposure during pregnancy could to contribute for development and severity of asthma in the offspring. Pregnant Wistar rats were submitted to FA inhalation (6.13 mg/m(3), 1 h/day, 5 days/week, for 21 days) or vehicle (distillated water). After 30 days of birth, the offspring was sensitized with ovalbumin (OVA)-alum and challenged with aerosolized OVA (1%, 15 min, 3 days). After 24 h the OVA challenge, the analyses were performed. Non-manipulated rats were used as basal parameters. Our data show that the exposure to high dose of FA during pregnancy predisposes the development of neutrophilic lung inflammation in the offspring, as observed by the profile of cells and cytokines in the lung. This study contributes to the understanding of effects of pollution on the development of lung diseases.

Associations between occupation exposure to Formaldehyde and semen quality, a primary study.

Formaldehyde (FA), a ubiquitous environmental pollutant, has long been suspected of having male reproductive toxicity. However, FA male reproductive toxicity was inconclusive due to dearth of human studies. Therefore, we sought to investigate whether occupational exposure to FA affects semen quality. Semen quality including five conventional parameters and seven kinematics parameters were compared between 114 male workers occupationally exposed to FA and 76 referents. FA exposure index (FEI) was measured and calculated. Our results showed that sperm progressive motility, total sperm motility, VCL, VSL and VAP were statistically significant decreased in FA exposure workers compared with the referents. Moreover, FEI was significantly negative associated with sperm progressive motility (β = −0.19, P = 0.01) and total sperm motility (β = −0.23, P = 0.004). In addition, a significant elevated risk of abnormal sperm progressive motility were observed in both low- (OR = 2.58; 95% CI: 1.11–5.97) and high-FA-exposed group (OR = 3.41; 95% CI: 1.45–7.92) respectively. Furthermore, a significant increased risk was also estimated for abnormal total sperm motility in both low- (OR = 3.21; 95% CI: 1.24–8.28) and high-FA-exposed group (OR = 4.84; 95% CI: 1.83–12.81) respectively. In conclusion, our study revealed the adverse effects of FA occupation exposure on semen quality, especially on sperm motion parameters.

Effect of carnosine supplementation on apoptosis and irisin, total oxidant and antioxidants levels in the serum, liver and lung tissues in rats exposed to formaldehyde inhalation

The main objective of the study has been to show whether carnosine has positive effects on liver and lung tissues of rats exposed to a range of formaldehyde concentrations, and to explore how irisin expression and antioxidant capacity are altered in these tissues by carnosine supplementation. Sprague-Dawley type male rats were divided into 8 groups with 6 animals in each: (I) Control; no chemical supplementation); (II) sham (100mg/kg/day carnosine); (III) low dose formaldehyde (LDFA) for 5 days/week; (IV) LDFA for 5 days/week and carnosine); (V) moderate dose formaldehyde (MDFA) for 5 days/week); (VI) MDFA for 5 days/week and carnosine; (VII) high dose formaldehyde (HDFA) for 5 days/week; (VIII) and HDFA for 5 days/week and carnosine. Sham and control groups were exposed to normal air. Irisin levels of the serum, liver and lung tissue supernatants were analyzed by ELISA, while the REL method was used to determine total oxidant/antioxidant capacity. Irisin production by the tissues was detected immunohistochemically. Increasing doses of FA decreased serum/tissue irisin and total antioxidant levels relative to the controls, as also to increases in TUNEL expressions, total oxidant level, oxidant and apoptosis index. Irisin expression was detected in hepatocyte and sinusoidal cells of the liver and parenchymal cells of the lung. In conclusion, while FA exposure reduces irisin and total oxidant in the serum, liver and lung tissues in a dose-dependent manner and increases the total antioxidant capacity, carnosine supplementation reduces the oxidative stress and restores the histopathological and biochemical signs.

Fusaric acid induced cell death and changes in oxidative metabolism of Solanum lycopersicum L.

BackgroundFusaric acid (FA) has been shown to stimulate the rapid development of disease symptoms, such as necrosis and foliar desiccation. In this study, we have evaluated the phytotoxicity of FA on tomato plants (Solanum lycopersicum L.). FA induced necrotic lesions in detached leaves, which are reminiscent of hypersensitive response (HR) lesions induced by plant-pathogen interactions and other abiotic stress factors.ResultsFA-treated tomato leaves exhibited visible necrotic lesion as a result of cell death which was evident by Evans blue staining, enhanced reactive oxygen species (ROS) levels and DNA degradation. Changes in the generation of O2.- and H2O2 as well as the activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were examined in FA-treated tomato leaves. It was observed that FA exposure stimulated oxidative burst in the leaves, resulting in a lasting activation of O2.- and H2O2 production. After first day of FA application, the H2O2 scavenging enzymes CAT and APX showed a strong activity decrease followed by gradual recovery to the control level after 2 and 3 days.ConclusionA concomitant increase in ROS production, the down regulation of antioxidative enzymes activities and upregulation of lipid peroxidation were crucial for the onset of cell death. These results suggested that FA-induced damage might result from ROS pathways. Thus, our experiments provide a useful model plant system for research on FA-induced plant cell death.Electronic supplementary materialThe online version of this article (doi:10.1186/s40529-014-0066-2) contains supplementary material, which is available to authorized users.

Effects of Ozone and Particulate Matter on Cardiac Mechanics: Role of the Atrial Natriuretic Peptide Gene

A positive association between air pollution exposure and increased human risk of chronic heart disease progression is well established. In the current study, we test two hypotheses: (1) the cardiac compensatory changes in response to air pollution are dependent on its composition and (2) specific cardiac adaptations are regulated by atrial natriuretic peptide (ANP). We address these hypotheses by initially examining the exposure effects of ozone (O(3)) and/or particulate matter (PM) on cardiac function in C57Bl/6J (B6) mice. Subsequently, the results are compared with cardiac functional changes to the same exposures in Nppa (the precursor gene for ANP) knockout (KO) mice. Separate groups of mice underwent 3 consecutive days of the same exposure sequence for 3h each consisting of the following: (1) 6h of filtered air (FAFA), (2) O(3) then FA (O(3)FA), (3) FA then carbon black (FACB), or (4) O(3) then CB. Cardiac function was assessed using a conductance catheter to generate cardiac pressure-volume loops 8-10h following each exposure sequence. As compared with FAFA, each sequence led to a substantial drop (as much as 33%) in stroke volume and cardiac output. However, these losses of cardiac function occurred by different compensatory mechanisms dependent on the pollutant composition. For example, O(3)FA exposure led to reductions in both end-systolic and end-diastolic left ventricular (LV) volumes, whereas FACB exposure led an increase in end-diastolic LV volume. These same cardiac compensatory changes were largely abolished in Nppa KO mice following O(3)FA or FACB exposure. These results suggest that cardiac functional changes in response to air pollution exposure are strongly dependent on the pollutant constituents, especially related to O(3) and/or PM. Furthermore, ANP regulation appears to be crucial to these cardiac compensatory mechanisms induced by air pollution.

Genetic polymorphisms in the formaldehyde dehydrogenase gene and their biological significance

The GSH-dependent formaldehyde dehydrogenase (FDH) is the most important enzyme for the metabolic inactivation of formaldehyde. We studied three polymorphisms of this gene with the intention to elucidate their relevance for inter-individual differences in the protection against the (geno-)toxicity of FA. The first polymorphism (rs11568816) was investigated using real-time PCR and restriction fragment analysis in 150 subjects. However, we did not find the polymorphic sequence in any of the subjects. We studied a second polymorphism (rs17028487), representing a base exchange (c.*114A>G) in exon 9 of the FDH gene. We analyzed 70 subjects with the SNaPshot Primer Extension method and subsequent analysis in a ABI PRISM 3100, but no variant allele was identified. A third polymorphism, rs13832 in exon 9 (c.*493G>T), was studied in a group of 105 subjects by the SNaPshot Primer Extension method. 43 of the subjects were heterozygous for the polymorphism (G/T), 46 homozygous for the T allele, and 16 were homozygous for the G-allele. Real-time RT-PCR measurements of FDH mRNA did not indicate a significant difference in transcript levels between the heterozygous and the homozygous groups. The in vitro comet assay after FA exposure of blood samples obtained from 5 homozygous GG and 3 homozygous TT subjects did not lead to a significant difference between these two groups. Altogether, our study did not identify biologically relevant polymorphisms in transcribed regions of the FDH gene, which may lead to inter-individual differences in the metabolic inactivation of FA.

Sequential air–liquid exposure of human respiratory cells to chemical and biological pollutants

Although indoor air has wide ranging effects on human health, the effects of environmental, chemical, and biological pollutants on the respiratory system are not fully understood. In order to clarify the health effects of airborne pollutant exposure, it would appear that toxicological evidence is needed to complement epidemiological observations to support by providing biological plausibility. The aim of this study is to manage air–liquid successive exposures to different pollutants such as a chemical pollutant (formaldehyde – FA), and a biological contaminant ( Aspergillus fumigatus – Asp) using our in vitro model. Human alveolar cells (A549) were exposed at the air–liquid interface in an exposure module, firstly to an environmental level of FA (50 μg/m 3) (or air) for 30 min, and 14 h later to Asp (7 × 10 8 spores/m 3) (or air) for 30 min. After 10 h post-incubation, cellular viability was assessed. Inflammation biomarkers (IL-8, MCP-1) were assayed by ELISA and by RT-PCR. Whatever the conditions, no cytotoxic effect was observed. FA followed by air exposure did not induce modification of production and expression of cytokines, confirming results with a unique FA exposure. Air followed by Asp exposure tended to induce IL-8 expression whereas IL-8 production tended to increase after FA and Asp exposure compared to FA and air exposure. The reaction of cells to sequential exposure to FA and Asp was moderate. These results show the feasibility of our model for sequential exposures to different types of environmental pollutants, allowing using it for preliminary assessment of cellular activity modification induced by airborne contaminants.

Relationship between susceptibility of formaldehyde metabolism and genetic polymorphisms of ALDH2 and cytochrome P4502E1

To study the relationship between occupational hazard susceptibility of formaldehyde and genetic polymorphisms of ALDH2 and CYP2E1. Genotypes of ALDH2 and CYP2E1 (Rsa I/Pst I site) of 107 subjects exposed to formaldehyde were determined with PCR-RFLP through testing peripheral blood lymphocytes, and the concentration of air formaldehyde in workplace and urine formic acid of the subjects were measured with HPLC. The relationship between genotypes and the urine formic acid increment was analyzed with nonparametric rank sum testing. The concentration of urine formic acid increment was related with ALDH2 genotypes (chi2 = 9.241, P < 0.05), and the means of urinary formic acid of subjects with GG, GA, AA genotype were (15.84 +/- 6.86), (12.06 +/- 7.94) and (7.31 +/- 5.37) mg/g creatinine, respectively. Mann-Whitney U test showed the formic acid increment between allele G homozygotes and allele A homozygotes was significantly different (U=26, P= 0.033). Our data indicated that the formaldehyde metabolism of ALDH2 GG homozygotic genotype was more active than ALDH2 AA homozygotic genotype(the difference of the two mean rank was 13.30). But the polymorphism of Rsa I / Pst I site of CYP2E1 5'-franking region was not correlated with the concentration of urine formic acid (chi2 = 4.285, P=0.117), and the urinary formic acid means of subjects with C1/C1, C1/C2, C2/C2 genotype were (11.14 +/- 7.91), (12.13 +/- 8.16) and (16.51 -/+ 3.78) mg/g creatinine, respectively. By Stepwise Multiple Regression Analysis, it showed that the urinary formic acid increment might be influenced by FA exposure concentration and ALDH2 genotype, and the model's R2 was 0.196. The metabolism of formaldehyde in human body was related with the genotypes of ALDH2, but not with the CYP2E1 (Rsa I/Pst I) polymorphisms.

Identification of Gene Markers for Formaldehyde Exposure in Humans

BackgroundFormaldehyde (FA) is classified as a human carcinogen and has been linked to increased leukemia rates in some epidemiologic studies. Inhalation of FA induces sensory irritation at relatively low concentrations. However, little is known concerning the cellular alterations observed after FA exposure in humans.ObjectivesOur aim was to profile global gene expression in Hs 680.Tr human tracheal fibroblasts exposed to FA and to develop biomarkers for the evaluation of FA exposure in humans.Methods and ResultsWe used gene expression analysis, and identified 54 genes designated as FA responsive. On the basis of these data, we conducted an exploratory analysis of the expression of these genes in human subjects exposed to high or low levels of FA. We monitored FA exposure by measuring the urinary concentration of thiazolidine-4-carboxylate (TZCA), a stable and quantitative cysteinyl adduct of FA. Nine genes were selected for real-time PCR analysis; of these, BHLHB2, CCNL1, SE20-4, C8FW, PLK2, and SGK showed elevated expression in subjects with high concentrations of TZCA.ConclusionThe identification of gene marker candidates in vitro using microarray analysis and their validation using human samples obtained from exposed subjects is a good tool for discovering genes of potential mechanistic interest and biomarkers of exposure. Thus, these genes are differentially expressed in response to FA and are potential effect biomarkers of FA exposure.

Effects of low-level formaldehyde exposure on synaptic plasticity-related gene expression in the hippocampus of immunized mice

We examined the effects of inhalative exposure to formaldehyde (FA, 400 ppb) on N-methyl- D-aspartate (NMDA) receptor subunits (NR2A and NR2B), dopamine receptor subtypes (D1 and D2), cyclic AMP responsive element-binding protein (CREB)-1, CREB-2, FosB/ΔFosB, and transient receptor potential vanilloid receptor (TRPV1) in the hippocampus of ovalbumin-immunized mice using quantitative real-time PCR. Western blot analyses for pCREB were performed. The mRNA levels of NR2A, D1 and D2 receptors, and CREB-1 were significantly increased by FA, but NR2B, CREB-2, FosB/ΔFosB, and TRPV1 mRNA levels remained unchanged. Treatment with MK-801 normalized the mRNA levels induced by FA. There was no significant effect of FA exposure and MK-801 treatment on the protein level of pCREB. These results indicate that FA exposure selectively up-regulates hippocampal gene expression in immunologically sensitized mice. The FA effects are presumably mediated by glutamatergic neurotransmission through NMDA receptors.

Subjective Symptoms of Medical Students Exposed to Formaldehyde during a Gross Anatomy Dissection Course

The purpose of this study is to investigate the safety of and to try to find the best plan to cope with exposure to FA for students during a gross anatomy dissection course. The FA exposure level and subjective symptoms was estimated. The relationship between exposure to FA and subjective symptoms of irritation were discussed for times; before, in the beginning period, in the middle period, and upon completion of the Anatomy Dissection Course. The geometric means of FA concentration were 32.7 micrograms/m3 (before), 891.3 micrograms/m3 (beginning), 763.3 micrograms/m3 (middle), and 238.9 micrograms/m3 (completion), respectively. Among them, FA-related symptoms were observed in 61.1 percent; 28.0 percent fell strong stress during the course, and 27.4 percent complained that their normal life situation was affected. Our results indicate that such subjective symptoms during the anatomy dissection course were related to the period spent in the anatomy dissection room. Our study suggests that shortening the time of each anatomy dissection practical class and reduction of the number of cadaver tables could help to reduce symptoms.