Seasonal variation in cortisol biomarkers in Hispanic mothers living in an agricultural region

Alteration of oral microbiome composition in children living with pesticide-exposed farm workers

Our prior work shows that azinphos-methyl pesticide exposure is associated with altered oral microbiomes in exposed farmworkers. Here we extend this analysis to show the same association pattern is also evident in their children. Oral buccal swab samples were analyzed at two time points, the apple thinning season in spring-summer 2005 for 78 children and 101 adults and the non-spray season in winter 2006 for 62 children and 82 adults. The pesticide exposure for the children were defined by the farmworker occupation of the cohabitating household adult and the blood azinphos-methyl detection of the cohabitating adult. Oral buccal swab 16S rRNA sequencing determined taxonomic microbiota proportional composition from concurrent samples from both adults and children. Analysis of the identified bacteria showed significant proportional changes for 12 of 23 common oral microbiome genera in association with azinphos-methyl detection and farmworker occupation. The most common significantly altered genera had reductions in the abundance of Streptococcus, suggesting an anti-microbial effect of the pesticide. Principal component analysis of the microbiome identified two primary clusters, with association of principal component 1 to azinphos-methyl blood detection and farmworker occupational status of the household. The children's buccal microbiota composition clustered with their household adult in ∼95% of the households. Household adult farmworker occupation and household pesticide exposure is associated with significant alterations in their children's oral microbiome composition. This suggests that parental occupational exposure and pesticide take-home exposure pathways elicit alteration of their children's microbiomes.

Depressive Symptoms of Latinx Women in Rural Farmworker and Urban Non-Farmworker Families in North Carolina

BACKGROUND

Mental health among low-income Latinx women in the United States (US), including those in farmworker families, is a health equity concern. This analysis (1) describes the depressive symptoms among Latinx women in rural farmworker families and urban non-farmworker families and (2) delineates immigration and acculturation, family composition and disruption, and financial characteristics associated with depressive symptoms experienced by these women.

METHODS

Data are from a 2019-2020 cross-sectional survey of 66 rural farmworker and 52 urban non-farmworker women with a child participating in a study of pesticide exposure and neurocognitive development. Depressive symptoms were measured with the CES-D Short Form.

RESULTS

The median (25th-75th percentiles) depressive symptom score reported was 2.0 (1.0-4.0), with 10 (8.5%) women having depressive symptom scores of 10 or greater. In bivariate analysis, among immigration and acculturation characteristics, women born in the USA and who spoke English fluently had lower depressive symptom scores. Among family composition and disruption characteristics, married women, and those with two adults in the household had lower depressive symptom scores. No financial status characteristic had statistically significant associations with depressive symptom score. In multivariate analysis, rural farmworker women had an expected median score one point lower than did urban non-farmworker women.

CONCLUSION

Addressing mental health among immigrant women, particularly those in farmworker families, is a complex undertaking. Rural versus urban locality provides a context for mental health. Determining the proximal determinants of locality requires further analysis.

Deregulatory miRNA-BDNF Network Inferred from Dynamic Expression Changes in Schizophrenia

(1) Background: Brain-derived neurotrophic factor (BDNF) is one of the promising risk genes for schizophrenia (SZ), a disease with prominent dysregulation of miRNA networks. Here, we present a study of miRNA-BDNF co-expression changes in peripheral blood of SZ patients. (2) Methods: The expression levels of the BDNF mRNA and three validated binding miRNAs—miR-124-3p, miR-132-3p, and miR-206—were quantified in the blood of 48 healthy controls and 32 SZ patients before and after 12 weeks of treatment. The co-expression patterns were evaluated in the three groups. (3) Results: The expression levels of BDNF were significantly downregulated in SZ patients compared to the controls. After the treatment, the expression levels of BDNF were upregulated, while the expression levels of the three miRNAs were downregulated. Co-expression analyses showed positive correlations of this network in the SZ patients, while weak negative correlations were observed in the healthy controls. After the 12-week treatment, the overall correlation between BDNF and the three miRNAs reached the levels comparable to the healthy controls. (4) Conclusions: Our findings suggest the involvement of the miRNA-BDNF network in the onset and treatment of SZ.

Evaluation of the relationship between residential orchard density and dimethyl organophosphate pesticide residues in house dust

Reducing residential pesticide exposure requires identification of exposure pathways. Compared to the agriculture worker 'take-home' and residential use pathways, evidence of the 'drift' pathway to pesticide exposure has been inconsistent. Questionnaire data from individuals (n = 99) and dust samples (n = 418) from households across three growing seasons in 2011 were from the For Healthy Kids! study. Summed dimethyl organophosphate pesticide (OP) (Azinphos-Methyl, Phosmet, and Malathion) concentrations were quantified from house dust samples. Spatially-weighted orchard densities surrounding households were calculated based on various distances from homes. Regression models tested associations between orchard density, residential pesticide use, agriculture worker residents, and summed dimethyl OP house dust concentrations. Estimated relationships between orchard density and dimethyl OP in house dust were mixed: a 5% increase in orchard density resulted in 0.3 and 0.5% decreases in dimethyl OP house dust concentrations when considering land-cover 750 m or 1250 m away from households, respectively, but null associations with land-cover 60 m or 200 m away. Dimethyl OP house dust concentrations were 400% higher within homes where at least two residents were agriculture workers. Despite inconclusive evidence for the drift pathway due to potential for bias, relationships between number of agriculture workers and dimethyl OP house dust concentration underscores the take-home pathway.

Contact to Nature Benefits Health: Mixed Effectiveness of Different Mechanisms

How can urban nature contribute to the reduction of chronic stress? We twice measured the concentration of the “stress hormone” cortisol in the hair of 85 volunteer gardeners (six months apart), relating cortisol level change to (self-reported) characteristics of their recreational activities. Both time spent in nature and physical activity led to decreases in cortisol, while time spent being idle led to an increase. At high levels of present stressors, however, the relationship for time spent in nature and for idleness was reversed. Time spent with social interaction had no effect on cortisol levels. Our results indicate that physical activity is an effective means of mitigating the negative effects of chronic stress. The results regarding the time spent in nature and time spent being idle are less conclusive, suggesting the need for more research. We conclude that if chronic stress cannot be abolished by eradicating its sources, public health may take to measures to reduce it—providing urban nature being one effective possibility.

Academic stress-induced changes in Th1- and Th2-cytokine response

Psychological stress stimulates physiological responses releasing catecholamines and corticoids, which act via corresponding receptors on immune cells, producing a shift in the cytokine balance. These responses are variable depending on the nature of stressors. The effect of the academic stress on the production of the Th1-cytokines (TNF-α, IFN-γ, IL-1β, IL-2, IL-6 and IL-8) and Th2-cytokines (IL-1ra, IL-4, IL-5 and IL-10) on 35 medical/health sciences students after completing their questionnaires was investigated. Blood samples were taken at three stages; baseline stage at the beginning, midterm and final academic examination stages. Plasma cortisol and cytokines were measured during the three stages. The last two stages were compared with the baseline non-stress period. Results of the stress induced during the final examination stage were the highest with a significant increase in cortisol release, IL-4, IL-5 and IL-1ra release with a shift in Th1:Th2 cytokines balance towards Th2. Whereby, the midterm stage did not show significant reduction in Th1-cytokines except for TNF-α, with an increase in IFN-γ level that was reduced in the third stage. Th2 cytokine, IL-1ra, had positive correlations with Th1 cytokines; IL-2 and IFN-γ in the second stage and IL-6 cytokine in the third stage. Cortisol was positively correlated with IL-8 in the last stage and heart rates had negative correlation with IL-10 in the first and last stages. Findings of this study indicate that exam stress down-regulates Th1 with a selective up-regulation of Th2-cytokines. In conclusion, Cortisol might have a role in suppressing the release of Th1- mediated cellular immune response which could increase the vulnerability among the students to infectious diseases.

Urinary microRNAs as potential biomarkers of pesticide exposure

MicroRNAs (miRNAs) are post-transcriptional regulators that silence messenger RNAs. Because miRNAs are stable at room temperature and long-lived, they have been proposed as molecular biomarkers to monitor disease and exposure status. While urinary miRNAs have been used clinically as potential diagnostic markers for kidney and bladder cancers and other diseases, their utility in non-clinical settings has yet to be fully developed. Our goal was to investigate the potential for urinary miRNAs to act as biomarkers of pesticide exposure and early biological response by identifying the miRNAs present in urine from 27 parent/child, farmworker/non-farmworker pairs (16FW/11NFW) collected during two agricultural seasons (thinning and post-harvest) and characterizing the between- and within-individual variability of these miRNA epigenetic regulators. MiRNAs were isolated from archived urine samples and identified using PCR arrays. Comparisons were made between age, households, season, and occupation. Of 384 miRNAs investigated, 297 (77%) were detectable in at least one sample. Seven miRNAs were detected in at least 50% of the samples, and one miRNA was present in 96% of the samples. Principal components and hierarchical clustering analyses indicate significant differences in miRNA profiles between farmworker and non-farmworker adults as well as between seasons. Six miRNAs were observed to be positively associated with farmworkers status during the post-harvest season. Expression of five of these miRNA trended towards a positive dose response relationship with organophosphate pesticide metabolites in farmworkers. These results suggest that miRNAs may be novel biomarkers of pesticide exposure and early biological response.