Use of permethrin and other pyrethroids and mortality in the Agricultural Health Study

Chiral pesticide permethrin promotes the antibiotic resistance genes dissemination by transformation: Different chiral isomers engage in distinct regulatory pathways

The global dissemination of antibiotic resistance genes (ARGs) poses an increasingly urgent threat to both environmental and human health. The extensive use of chiral permethrin (PM), the most popular synthetic type I pyrethroid insecticide worldwide, has led to its increased detection in aquatic environments. However, our understanding of PM's role in spreading ARGs is still limited. Here, we systematically assessed the effects of two chiral isomers of 1R-cis-PM (CPM) and 1R-trans-PM (TPM) on the dissemination of ARGs in the aquatic environments by using a natural transformation (NT) model comprising plasmid pWH1274 and Acinetobacter baylyi ADP1. It was found that reactive oxygen species (ROS) was the main factor facilitating the NT of ARGs mediated by CPM and TPM, although their respective production mechanisms exhibited distinct pathways: CPM generates ROS primarily through the primary electron transport chain (ETC), whereas TPM does so via a secondary ETC. Furthermore, CPM enhanced NT by improving the bacterial competent state, while TPM promotes it by enhancing recombination. It was confirmed that both CPM and TPM have the potential to accelerate the spread of ARGs through distinct mechanisms. These findings will help us understand that different chiral isomers may pose risks through distinct mechanisms.

Exposure to pesticides in Chile and its relationship with carcinogenic potential: a review

Background

The widespread application of pesticides in agriculture and the consequent heightened human exposure to these potentially harmful substances present considerable environmental and health risks. The potential link to cancer is particularly concerning, underscoring the urgent need for more sustainable and health-conscious agricultural practices. Pesticides are pervasive global contaminants, with exposure occurring through various routes. Improper use is associated with genotoxicity, neurobehavioral problems, thyroid dysfunction, reproductive issues, and cancer, among other deleterious damages. While pesticide exposure is evident in Chile, a direct link to cancer remains uncertain.

Objective

To examine the scientific evidence on pesticides exposure in the environment and human populations, and its relationship with cancer in Chilean territory.

Methods

The search for original articles was performed in international peer-reviewed scientific databases, including Scopus, Web of Science (WoS), and PubMed Advanced Search Builder. Following the PRISMA extension for review guidelines, the search included studies on environmental pesticide exposure, human biomarker assessments, experimental investigations, and the potential pesticide-cancer associations in Chile. Foreign studies, systematic reviews, and meta-analyses were excluded.

Results

Among the 83 qualifying studies conducted between 1996 and 2024, elevated pesticide exposure risks were documented, with 71% indicating high concentrations that may pose health risk. Additionally, 20% of studies reported significant chlorinated compounds, including organochlorines (OCs) and polychlorinated biphenyls (PCBs), while 79.5% identified carcinogenic to humans classified by the International Agency for Research on Cancer. The review emphasizes the urgent need to update pesticide-related regulations in Chile, including implementing bans or restrictions on carcinogenic pesticides and establishing stricter standards for allowable pesticide residue levels in food.

Conclusion

Long-term epidemiological studies are essential to establishing concrete links between pesticide exposure and specific types of cancer. Additionally, investigating epigenetic markers associated with pesticide exposure, especially in occupational settings, is critical. Furthermore, allocating resources and prioritizing further research is fundamental, particularly in regions with substantial agricultural exposure.

Impact of pesticides exposure and type 2 diabetes risk: a systematic review and meta-analysis

OBJECTIVE

We conducted a systematic review and meta-analysis of observational studies that assessed the relationship between pesticides exposure and type 2 diabetes. We also examined the presence of heterogeneity and biases across the available studies.

METHODS

We conducted a comprehensive literature search of peer-reviewed studies published from 2011 to 2023, without language limitations. A random-effects model was employed to calculate the overall odds ratio (OR) and its corresponding 95% confidence interval (CI).

RESULTS

We included 19 studies (n = 12 case-control and n = 7 cross-sectional) for a total of 45,813 participants in our analysis. Our findings revealed a notable correlation between pesticide exposure and type 2 diabetes (non-specific definition) when not limiting pesticide types (OR: 1.19, 95% CI: 1.11-1.28). Subgroup analysis identified associations between pyrethroid (OR: 1.17, 95% CI: 1.05-1.30) and type 2 diabetes, as well as between organochlorine (OR: 1.26, 95% CI: 1.11-1.43) and type 2 diabetes. However, no statistically significant association was observed between herbicide exposure and the onset of type 2 diabetes (OR: 1.26, 95% CI: 0.91-1.75). In the elderly group, pesticide exposure significantly heightened the risk of type 2 diabetes (OR: 1.25, 95% CI: 1.14-1.38), with no statistically significant heterogeneity among studies (I2 = 14.2%, p = 0.323).

CONCLUSIONS

Pesticide (organochlorine and pyrethroid) exposure constitutes a risk factor for type 2 diabetes.

GPR39-mediated ERK1/2 signaling reduces permethrin-induced proliferation of estrogen receptor α-negative cells

Certain insecticides are known to have estrogenic effects by activating estrogen receptors through genomic transcription. This has led researchers to associate specific insecticide use with an increased breast cancer risk. However, it is unclear if estrogen receptor-dependent pathways are the only way in which these compounds induce carcinogenic effects. The objective of this study was to determine the impact of the pyrethroid insecticide permethrin on the growth of estrogen receptor negative breast cancer cells MDA-MB-231. Using tandem mass spectrometric techniques, the effect of permethrin on cellular protein expression was investigated, and gene ontology and pathway function enrichment analyses were performed on the deregulated proteins. Finally, molecular docking simulations of permethrin with the candidate target protein was performed and the functionality of the protein was confirmed through gene knockdown experiments. Our findings demonstrate that exposure to 10-40 μM permethrin for 48 h enhanced cell proliferation and cell cycle progression in MDA-MB-231. We observed deregulated expression in 83 upregulated proteins and 34 downregulated proteins due to permethrin exposure. These deregulated proteins are primarily linked to transmembrane signaling and chemical carcinogenesis. Molecular docking simulations revealed that the overexpressed transmembrane signaling protein, G protein-coupled receptor 39 (GPR39), has the potential to bind to permethrin. Knockdown of GPR39 partially impeded permethrin-induced cellular proliferation and altered the expression of proliferation marker protein PCNA and cell cycle-associated protein cyclin D1 via the ERK1/2 signaling pathway. These findings offer novel evidence for permethrin as an environmental breast cancer risk factor, displaying its potential to impact breast cancer cell proliferation via an estrogen receptor-independent pathway.

Is a Good Sleep on Mosquito-Free Nights Worth the Risk of Lymphoma Associated with the Use of Household Insecticides? A Case-Control Study of Lymphoma Subtypes in Adults

BACKGROUND

The evidence linking the use of household pesticides and the risk of lymphoma is scanty.

METHODS

We explored the hypothesis in a population-based case-control study on lymphoma conducted in Sardinia, Italy, in 1998-2004, including 325 cases and 465 population controls and data on lifetime frequency, seasonality, and years of use of household insecticides and potential confounders. We calculated the risk of lymphoma (all subtypes) and its major subtypes associated with using household insecticides in three time windows (up to 1978, from 1979-2001, and 2002 onwards) with unconditional logistic regression adjusting by age, sex, education, and occupational exposure to pesticides.

RESULTS

Household insecticides did not increase risk of lymphoma (all subtypes), Hodgkin's lymphoma, B-cell lymphoma, and the major B-cell lymphoma subtypes. The risk of multiple myeloma (MM) but not the other subtypes showed a non-significant upward trend (p = 0.203) with increasing quartiles of days of use in the time window when propoxur was the most popular household insecticide.

CONCLUSIONS

Our results suggest no association between the household use of insecticides and the risk of lymphoma. Further studies are warranted to confirm or discard an association between MM risk and the use of propoxur.

Maternal and Paternal Household Pesticide Exposure During Pregnancy and Risk of Childhood Acute Lymphoblastic Leukemia

OBJECTIVE

The aim of this study was to investigate whether risk estimates for childhood acute lymphoblastic leukemia change when restricting model comparison groups to "nonpesticide exposure" (NPE10) households.

METHODS

Cases ( n = 1810) 15 years or younger were identified through Children's Cancer Group institutions between 1989 and 1993 and age-/sex-matched to controls ( n = 1951). Household pesticide use during pregnancy/month prior was collected via telephone. NPE10 comparison group reporting no parental exposure to 10 pesticide classes was identified.

RESULTS

Adjusted odds ratios increased from 15% to 49% when limiting the comparison to NPE10. Maternal termite insecticide exposure was associated with greatest risk (adjusted odds ratio, 4.21; 95% confidence interval, 2.00-8.88). There was minimal evidence of interaction by child sex or occupational pesticide exposure, and no monotonic dose-response pattern with frequency of use (times per year).

CONCLUSIONS

Elevated risks are consistent with published pooled-/meta-analyses and DNA damage. The consistency and magnitude of these associations warrant product labeling, exposure reduction interventions, or both.