Prenatal Particulate Matter Exposure Is Associated with Saliva DNA Methylation at Age 15: Applying Cumulative DNA Methylation Scores as an Exposure Biomarker

Background: Exposure in utero to particulate matter (PM2.5 and PM10) is associated with maladaptive health outcomes. Although exposure to prenatal PM2.5 and PM10 has cord blood DNA methylation signatures at birth, signature persistence into childhood and saliva cross-tissue applicability has not been tested. Methods: In the Fragile Families and Child Wellbeing Study, a United States 20-city birth cohort, average residential PM2.5 and PM10 during the three months prior to birth was estimated using air quality monitors with inverse distance weighting. Saliva DNA methylation at ages 9 (n = 749) and 15 (n = 793) was measured using the Illumina HumanMethylation 450 k BeadArray. Cumulative DNA methylation scores for particulate matter were estimated by weighting participant DNA methylation at each site by independent meta-analysis effect estimates and standardizing the sums. Using a mixed-effects regression analysis, we tested the associations between cumulative DNA methylation scores at ages 9 and 15 and PM exposure during pregnancy, adjusted for child sex, age, race/ethnicity, maternal income-to-needs ratio, nonmartial birth status, and saliva cell-type proportions. Results: Our study sample was 50.5% male, 56.3% non-Hispanic Black, and 19.8% Hispanic, with a median income-to-needs ratio of 1.4. Mean exposure levels for PM2.5 were 27.9 μg/m3/day (standard deviation: 7.0; 23.7% of observations exceeded safety standards) and for PM10 were 15.0 μg/m3/day (standard deviation: 3.1). An interquartile range increase in PM2.5 exposure (10.73 μg/m3/day) was associated with a −0.0287 standard deviation lower cumulative DNA methylation score for PM2.5 (95% CI: −0.0732, 0.0158, p = 0.20) across all participants. An interquartile range increase in PM10 exposure (3.20 μg/m3/day) was associated with a −0.1472 standard deviation lower cumulative DNA methylation score for PM10 (95% CI: −0.3038, 0.0095, p = 0.06) across all participants. The PM10 findings were driven by the age 15 subset where an interquartile range increase in PM10 exposure was associated with a −0.024 standard deviation lower cumulative DNA methylation score for PM10 (95% CI: −0.043, −0.005, p = 0.012). Findings were robust to adjustment for PM exposure at ages 1 and 3. Conclusion: In utero PM10-associated DNA methylation differences were identified at age 15 in saliva. Benchmarking the timing and cell-type generalizability is critical for epigenetic exposure biomarker assessment.

Toxicity Evaluation of Chlorpyrifos Metabolite 3,5,6-trichloro-2-pyridinol to Eisenia fetida in Different Soils

The present study utilized a biomarker response method to evaluate the effect of 3,5,6-trichloro-2-pyridinol (TCP) in artificial and natural soils on Eisenia fetida after 7, 14, 28, 42 and 56 days exposure. Biomarker responses were standardized to calculate the Integrated Biomarker Response (IBR) index. The influence of soil type on TCP toxicity was assessed. Results indicated that TCP induced excessive reactive oxygen species, caused oxidative stress, DNA damage to earthworm, which is similar to its parent chemical chlorpyrifos. The IBR index of three enzymes activities showed that TCP induced the enzymes activities of earthworm in red clay was stronger than the other three soils. Specifically, chlorpyrifos exposure group showed a lower toxicity than TCP exposure group after 28 days exposure but a higher toxicity than TCP exposure group after 56 days exposure. Despite the deficiencies of this study, the above information is of great significance for assessing the risk of chlorpyrifos and its metabolite TCP pollution in soil ecosystems.

Urinary 1-aminopyrene level in Koreans as a biomarker for the amount of exposure to atmospheric 1-nitropyrene

Abstract1-Nitropyrene (1-NP) is a major nitro-polycyclic aromatic hydrocarbon (nitro-PAH), and a common constituent in diesel exhaust particles (DEPs). Absorbed 1-nitropyrene is partly metabolized to 1-aminopyrene and excreted in urine. Recently, the number of diesel cars has been increasing, which could be a major cause of air pollution, resulting elevated levels of traffic-related DEPs around cities. The aim of this study was to investigate the usability of 1-aminopyrene (1-AP) as a biomarker for DEP exposure by examining the association between urinary 1-AP concentration and the amount of exposure to atmospheric 1-NP. The study subjects included 65 individuals who work on vehicular roads or bus terminals. Their 24 h urine samples were collected, and atmospheric air was sampled using a personal air sampler for 24 h. Urinary 1-AP and atmospheric nitro-PAH levels were measured using a high-pressure liquid chromatography-fluorescence detector (HPLC-FD). The average urine 1-AP concentration was 0.334 pg/g creatinine. Urinary 1-AP levels were significantly correlated with 1-NP level exposure (r = 0.385, p = 0.002) but not with the other nitro-PAHs. When the subjects were classified into high-and low-exposure groups, a significant association was only found in the high exposure group (r = 0.357, p = 0.045). In conclusion, there was a significant correlation between 1-NP exposure and urinary 1-AP concentration; therefore, urinary 1-AP level could be used as an exposure biomarker for DEP.

IL-10-producing B cells regulated 1,3-β-glucan induced Th responses in coordinated with Treg

Background: Repeated exposure to fungi contaminated dust can lead to multiple adverse effect on lung, such as hypersensitivity pneumonitis, granuloma even irreversible fibrosis. 1,3-β-glucan, as the major cell wall component of fungi, was considered as its exposure biomarker. Existing studies showed that series of Th response were involved in 1,3-β-glucan induced hypersensitivity pneumonitis, in which macrophages, regulatory T cells (Treg) and IL-10 producing B cells were reported to participate. The reciprocal interaction among those critical immune cells in 1,3-β-glucan induced inflammation were not investigated yet.Results: To clarify the regulatory mechanism of IL-10 producing B cells on Th and Treg, current study set up a primary cell co-culture system. Anti-CD22 antibody was injected intraperitoneally to generate IL-10 producing B cells deficiency mouse model. Cells were isolated and purified from different groups’ mice. Flow cytometry was used to check the phenotype of different cell subtypes. CBA assay and realtime PCR were used to examine the levels of multiple cytokines. Our results indicated that IL-10 producing B cells were involved in modulating 1,3-β-glucan induced inflammatory response. The modulation of IL-10 producing B cells on Th response after 1,3-β-glucan treatment was independent on cell-cell contact. What’s more, the modulation pattern of IL-10 producing B cells might be impaired without Treg response.Conclusions: IL-10-producing B cells regulated 1,3-β-glucan induced Th responses in coordinated with Treg.

Using Evidence Factors to Clarify Exposure Biomarkers

A study has 2 evidence factors if it permits 2 statistically independent inferences about 1 treatment effect such that each factor is immune to some bias that would invalidate the other factor. Because the 2 factors are statistically independent, the evidence they provide can be combined using methods associated with meta-analysis for independent studies, despite using the same data twice in different ways. We illustrate evidence factors, applying them in a new way in investigations that have both an exposure biomarker and a coarse external measure of exposure to a treatment. To illustrate, we consider the possible effects of cigarette smoking on homocysteine levels, with self-reported smoking and a cotinine biomarker. We examine joint sensitivity of 2 factors to bias from confounding, a central aspect of any observational study.

Mycotoxin exposure is associated with increased risk of esophageal squamous cell carcinoma in Huaian area, China

Background Consumption of moldy food has previously been identified as a risk factor for esophageal squamous cell carcinoma (ESCC) in high-risk countries; however, what contributing roles these dietary carcinogenic mycotoxins play in the etiology of ESCC are largely unknown. Methods A mycotoxin biomarker-incorporated, population-based case-control study was performed in Huaian area, Jiangsu Province, one of the two high-risk areas in China. Exposure biomarkers of aflatoxins (AF) and fumonisins (FN) were quantitatively analyzed using HPLC-fluorescence techniques. Results Among the cases (n = 190), the median levels of AF biomarker, serum AFB1-lysine adduct, and FN biomarker, urinary FB1, were 1.77 pg/mg albumin and 176.13 pg/mg creatinine, respectively. Among the controls (n = 380), the median levels of AFB1-lysine adduct and urinary FB1 were 1.49 pg/mg albumin and 56.92 pg/mg creatinine, respectively. These mycotoxin exposure biomarker levels were significantly higher in cases as compared to controls (p < 0.05 and 0.01, respectively). An increased risk to ESCC was associated with exposure to both AFB1 and FB1 (p < 0.001 for both). Conclusions Mycotoxin exposure, especially to AFB1 and FB1, was associated with the risk of ESCC, and a greater-than-additive interaction between co-exposures to these two mycotoxins may contribute to the increased risk of ESCC in Huaian area, China.