Dysregulation of immune responses in an allergic mouse model following low-level toluene exposure

Exposure to Volatile Organic Compounds May Contribute to Atopic Dermatitis in Adults

BACKGROUND

Volatile organic compounds (VOC) are major indoor air pollutants. Previous studies reported an association between VOC exposure and allergic diseases. Here, we aimed to explore the relationship between VOC exposure and atopic dermatitis (AD) in adults.

METHODS

We prospectively enrolled 31 adult AD patients and 11 healthy subjects as controls. Urine metabolite levels of VOCs, including 1.3-butadiene, acrylamide, benzene, toluene, and xylene, were all determined with liquid chromatography-mass spectrometry. The relationship between AD and log-transformed urine levels of VOC metabolites were examined using a multivariate linear regression model adjusted for age and sex. We also treated mouse bone marrow-derived cells (BMMCs) with 1,3-butadiene and toluene and measured the release of β-hexosaminidase.

RESULTS

Our results demonstrated that creatinine-corrected urine levels of N-Acetyl-S- (3,4-dihydroxybutyl)-L-cysteine (DHBMA), N-Acetyl-S-(2-carbamoyl-2-hydroxyethyl)-L-cysteine (GAMA), and N-Acetyl-S-(benzyl)-L-cysteine (BMA) were all elevated in AD patients compared with controls. In a multivariate linear regression model, creatinine-corrected urine levels of BMA (a toluene metabolite) and DHBMA (a 1,3-butadiene metabolite) appeared elevated in AD patients, although statistical significance was not reached after correction for multiple comparisons. In addition, 1,3-butadiene and toluene could stimulate BMMCs to degranulate as much as compound 48/80.

CONCLUSIONS

Some VOCs, such as 1,3-butadiene and toluene, might be associated with AD pathogenesis in adults.

Inhalation toxicity of indoor air pollutants in Drosophila melanogaster using integrated transcriptomics and computational behavior analyses

We conducted an inhalation toxicity test on the alternative animal model, Drosophila melanogaster, to investigate potential hazards of indoor air pollution. The inhalation toxicity of toluene and formaldehyde was investigated using comprehensive transcriptomics and computational behavior analyses. The ingenuity pathway analysis (IPA) based on microarray data suggests the involvement of pathways related to immune response, stress response, and metabolism in formaldehyde and toluene exposure based on hub molecules. We conducted a toxicity test using mutants of the representative genes in these pathways to explore the toxicological consequences of alterations of these pathways. Furthermore, extensive computational behavior analysis showed that exposure to either toluene or formaldehyde reduced most of the behavioral parameters of both wild-type and mutants. Interestingly, behavioral alteration caused by toluene or formaldehyde exposure was most severe in the p38b mutant, suggesting that the defects in the p38 pathway underlie behavioral alteration. Overall, the results indicate that exposure to toluene and formaldehyde via inhalation causes severe toxicity in Drosophila, by inducing significant alterations in gene expression and behavior, suggesting that Drosophila can be used as a potential alternative model in inhalation toxicity screening.

Activation of transcription factors in a mouse lung following exposure to environmental chemical and biological agents

Environmental biological and chemical agents can modulate innate and acquired immunity in the lung via the stimulation of Toll-like receptors (TLRs). To investigate the effect of environmental chemical agents on the activation of NF-κB and activator protein (AP)-1 subunits and the role of TLR4 signaling in the lung, C3H/HeN and C3H/HeJ (TLR4-defective) mice were exposed to 0 or 50 ppm of toluene for 6 hr/day, 5 days/week for 6 weeks. Some groups of mice were also stimulated with OVA or LPS as a biological agent. The DNA-binding activities of the NF-κB subunits (p50, p52, p65 and RelB) and AP-1 family members (FosB, c-Fos, +c-Jun, JunD) were compared using TransAM ELISA kits. Exposure to toluene alone produced no significant changes in both mice. Although stimulation with OVA or LPS alone significantly increased the DNA binding activities of p50 and p52 in C3H/HeN mice, there were no interactions between biological factors and toluene. In the C3H/HeJ mice, stimulation with OVA or LPS increased p65 and p52 binding activity and the combination of exposure to toluene and OVA significantly increased the DNA binding activities of the p65 and p52 in the lung. During AP-1 activation, co-exposure to toluene and OVA increased JunD binding activity in C3H/HeJ mice, while co-exposure to toluene and LPS influenced c-Fos binding activity in C3H/HeN mice. These results indicate that TLR4 may play an important role in activation of NF-κB or AP-1 family following exposure to environmental biological and chemical agents.

Perinatal exposure to solvents and wheezing, eczema and food allergies at age 2

OBJECTIVES

The time from the prenatal period through early childhood is an important window of vulnerability for the developing immune and respiratory systems, both sensitive to environmental chemicals such as solvents. This study sought to examine the effects of solvent exposure during the prenatal and postnatal periods on wheezing, eczema and food allergies in early childhood.

METHODS

This study, based on the PELAGIE cohort, included 1505 mother-child pairs with measurements of prenatal and postnatal solvent exposures and data on wheezing, eczema or food allergies. The maternal occupation reported at inclusion, in early pregnancy allowed us to define prenatal occupational solvent exposure (by three specific job-exposure matrices). Data on prenatal and postnatal domestic solvent exposure, that is exposure to products that contain solvents, were obtained from self-administered questionnaires, once at inclusion and again when the child was 2 years old. Outcome data was collected at the 2-year follow-up. Associations between exposures and outcomes were estimated by logistic regression models, after adjustment for potential confounders.

RESULTS

No association was observed between prenatal exposure to solvents and the outcomes studied. Postnatal exposure was associated with an increased risk of wheezing (OR=1.80 (95% CI 1.25 to 2.59)) which persisted after adjustment for prenatal exposure. No significant association was observed with eczema or food allergies.

CONCLUSIONS

Postnatal exposure to solvent-containing products in the home may increase the risk of wheezing in early childhood. Follow-up studies are needed to determine if the health effects observed at age 2 persist at later ages.