Environmentally relevant exposure to cypermethrin aggravates diet-induced diabetic symptoms in mice: The interaction between environmental chemicals and diet

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.

Association between mixed exposure of non-persistent pesticides and liver fibrosis in the general US population: NHANES 2013-2016

People are continually and simultaneously exposed to various non-persistent pesticides as these chemicals are ubiquitously distributed in the environment. Toxicological studies have indicated the associations between non-persistent pesticides and liver fibrosis in vitro and in vivo. However, epidemical study on the deleterious effect of non-persistent pesticides on the risk of liver fibrosis is rather limited. To examine the relationship between mixed non-persistent pesticides exposure and liver fibrosis, and to identify the potential pesticides of significant importance, this study enrolled the representative individuals from the NHANES 2013-2016 survey cycles, in which urinary non-persistent pesticides were measured. Liver fibrosis was determined based on the alternative noninvasive tests Fibrosis-4 index (FIB-4) and Hepamet Fibrosis Score (HFS). Survey-weighted linear/logistic regression and Bayesian kernel machine regression (BKMR) were used to detected the independent and combined associations between non-persistent pesticides and liver fibrosis, respectively. In single exposure analysis, significant and persistent associations were identified for 3,5,6-trichloropyridinol (TCPY), para-nitrophenol (PNP), glyphosate (GLYP) and 2,4-dichlorophenoxyacetic acid (2,4-D) exposure with both continuous and dichotomous liver fibrosis outcomes. Of them, TCPY and GLYP had the highest effect estimates, with the corresponding FIB-4 coefficient (β) being 0.09 (0.05-0.13, model 3) and 0.09 (0.06-0.12, model 3), respectively. In BKMR analysis, positive associations between pesticides mixture and FIB-4 and HFS liver fibrosis were identified. The results of Posterior Inclusion Probability (PIP) further showed that GLYP, TCPY, and PNP were the main contributors to the overall effects of pesticides mixture, and the corresponding PIPs were 1.000 (1.000), 1.000 (0.914) and 0.972 (0.819) for FIB-4 (HFS) liver fibrosis, respectively. This study indicates that exposure to non-persistent pesticides mixture is associated with increased risk of liver fibrosis in humans, and provide new insight into the hepatotoxic potential of non-persistent pesticides.

The pyrethroid insecticide deltamethrin disrupts neuropeptide and monoamine signaling pathways in the gastrointestinal tract

Enteroendocrine cells (EECs) are a rare cell type of the intestinal epithelium. Various subtypes of EECs produce distinct repertoires of monoamines and neuropeptides which modulate intestinal motility and other physiologies. EECs also possess neuron-like properties, suggesting a potential vulnerability to ingested environmental neurotoxicants. One such group of toxicants are pyrethroids, a class of prevalent insecticides used residentially and agriculturally. Pyrethroids agonize voltage-gated sodium channels (VGSCs), inducing neuronal excitotoxicity, and affect the function of monoamine-producing neurons. Given their anatomical location at the interface with the environment and their expression of VGSCs, EECs likely represent a vulnerable cell-type to oral pyrethroid exposure. In this study, we used the EEC cell line, STC-1 cells, to evaluate the effects of the common pyrethroid deltamethrin on the functional status of EECs. We find that deltamethrin impacts both expression of serotonergic pathways and inhibits the adrenergic-evoked release of an EEC hormone, GLP-1, in vitro. In a mouse model of oral exposure, we found that deltamethrin induced an acute, yet transient, loss of intestinal motility, in both fed and fasted conditions. This constipation phenotype was accompanied by a significant decrease in peripheral serotonin production and an inhibition of nutrient-evoked intestinal hormone release. Together, these data demonstrate that deltamethrin alters monoaminergic signaling pathways in EECs and regulates intestinal motility. This work demonstrates a mechanistic link between pyrethroid exposure and intestinal impacts relevant to pyrethroid-associated diseases, including inflammatory bowel disease, neurodegenerative disease, and metabolic disorders.

Parabens promotes invasive properties of multiple human cells: A potential cancer-associated adverse outcome pathway

Parabens are esters of p-hydroxybenzoic acid, which have been used as preservatives and considered safe for nearly a century, until the last two decades when concerns began to be raised about their association with cancers. Knowledge of the mode of action of parabens on the metastatic properties of different cancer cells is still very limited. In the present study, we investigated the effects of methylparaben (MP) and propylparaben (PP) on cell invasion and/or migration in multiple human cancerous and noncancerous cells, including hepatocellular carcinoma cells (HepG2), cervical carcinoma cells (HeLa), breast carcinoma cells (MCF-7), and human placental trophoblasts (HTR-8/SVneo). MP and PP at concentrations in a range of 5-500 μg/L significantly promoted the invasion of four cell lines, with a minimum effective concentration of 5 μg/L. MP and PP up-regulated the expression levels and enzymatic activities of matrix metalloproteinase 2 and 9 (MMP2 and MMP9), as well as altered the expression of the tissue inhibitors of metalloproteinase 1 and 2 (TIMP1 and TIMP2) in four cell lines, suggesting MMPs/TIMPs as potential key events (KEs) for paraben-induced cell invasion. Activation of the p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun N-terminal protein kinases 1/2 (JNK1/2) signaling pathways was required for MP- and PP-promoted invasion of four cell lines, suggesting MAPK signaling pathways as candidates for KEs in cancer or noncancerous cells response to paraben exposure. This study showed for the first time that the two widely used parabens, MP and PP, promoted invasive capacity of multiple human cells through a common mode of action. This study provides evidence for the establishment of a potential cancer-associated AOP for parabens based on pathway-specific mechanism(s), which contributes towards assessing the health risks of these environmental chemicals.

Spatial distribution and risk assessment of pyrethroid insecticides in surface waters of East China Sea estuaries

Pyrethroid insecticides are the most commonly used household insecticides and pose substantial risks to marine aquatic organisms. many studies have detected pyrethroid insecticides in the waters and estuaries of the western United States, but their distributions within western Pacific estuaries have not been reported. Accordingly, we used high-throughput organic analyses combined with high volume solid-phase extraction to comprehensively assess 13 pyrethroid insecticides in East China Sea estuaries and the Huangpu River. The results demonstrated the presence of various ∑13pyrethroid insecticides in East China Sea estuaries (mean and median values of 8.45 ± 5.57 and 7.78 ng L-1, respectively), among which cypermethrin was the primary contaminant. The concentrations of ∑12pyrethroid insecticide detected in the surface waters at the Huangpu River (mean 6.7 ng L-1, outlet 16.4 ng L-1) were higher than those in the Shanghai estuary (4.7 ng L-1), suggesting that runoff from inland areas is a notable source of insecticides. Wetlands reduced the amount of runoff containing pyrethroid insecticides that reached the ocean. Several factors influenced pesticide distributions in East China Sea estuaries, and higher proportions were derived from agricultural sources than from urban sources, with a higher proportion of agricultural sources than urban sources, influenced by anthropogenic use in the region. Permethrin and cypermethrin were the main compounds contributing to the high ecological risk in the estuaries. Consequently, to prevent risks to marine aquatic life, policymakers should aim to reduce insecticide contaminants derived from urban and agricultural sources.

Hepatoprotective and Antioxidant Effects of Nanopiperine against Cypermethrin via Mitigation of Oxidative Stress, Inflammations and Gene Expression Using qRT-PCR

Cypermethrin (Cyp) is a pyrethroid that has been associated with the toxicity of various organs. The aim of our study was to evaluate the hepatoprotective and antioxidant activities of nano-piperine (NP) against Cyp toxicity. Cyp (50 mg/kg) was administered orally in all animals of groups III-VI for 15 days. Groups IV-VI each received three doses of NP (125, 250, and 500 µg/kg/day) for 10 days after receiving the Cyp dosage, which was given after 1 h. A rise in serum biomarkers (ALT, AST, ALP, total protein, and albumin), which are indicators of toxicity alongside anomalous oxidative stress indices (lipid peroxidation (LPO), glutathione (GSH), superoxide dismutase (SOD) and catalase), was detected. After Cyp treatment, we observed upregulated cytokines, caspase expression, and histological analysis that the showed distortion of cell shape. However, the administration of NP dramatically reversed all of the Cyp-induced alterations, inducing reductions in serum marker levels, stress level, the production of cytokines, and caspase expression. Additionally, all of the histopathological alterations were minimized to values that were comparable to normal levels. The present findings suggested that NP exhibits potent antioxidant and anti-inflammatory activities that can protect rats' livers against Cyp-induced liver damage through hepatoprotective activities.