The Role of Di(2-Ethylhexyl) Phthalate as an Exacerbating Factor in Chronic Spontaneous Urticaria

Relationship between the use of plastics in refrigerator food storage and urine phthalate metabolites: the Korean National Environmental Health Survey (KoNEHS) cycle 3

Background

Plastics are high-molecular-weight materials composed of long carbon chains. They are prevalent in daily life, present in various items such as food containers and microwavable packaging. Phthalates, an additive used to enhance their flexibility, are endocrine-disrupting chemicals. We utilized the data from the Korean National Environmental Health Survey (KoNEHS) cycle 3, representing the general South Korean population, to investigate the relationship between the use of plastics in refrigerator food storage and phthalate exposure.

Methods

We assessed 3,333 adult participants (aged ≥ 19 years) including 1,526 men and 1,807 women, using data from KoNEHS cycle 3. Using the 75th percentile concentration, urine phthalate metabolites were categorized into high and low-concentration groups. χ2 test was conducted to analyze variations in the distribution of each variable, considering sociodemographic factors, health-related factors, food intake, the use of plastics, and the concentration of urine phthalate metabolites as the variables. To calculate odds ratios (ORs) for the high-concentration group of urine phthalate metabolites based on the use of plastics in refrigerator food storage, logistic regression analysis was conducted.

Results

In men, the use of plastics in refrigerator food storage had significantly higher adjusted ORs compared to those using the others. The adjusted ORs were calculated as follows: mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) had an OR of 1.35 (95% confidence interval [CI]: 1.05-1.72), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) had an OR of 1.48 (95% CI: 1.16-1.88), mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP) had an OR of 1.32 (95% CI: 1.04-1.66), ∑di(2-ethylhexyl) phthalate (∑DEHP) had an OR of 1.37 (95% CI: 1.08-1.74) and mono-n-butyl phthalate (MnBP) had an OR of 1.44 (95% CI: 1.13-1.84).

Conclusion

The concentrations of urine phthalate metabolites (MEHHP, MEOHP, MECPP, ∑DEHP, and MnBP) were significantly higher in men who used plastics in refrigerator food storage compared to those using the others.

The effect of apigenin, an aryl hydrocarbon receptor antagonist, in Phthalate-Exacerbated eosinophilic asthma model

Endocrine disrupting chemicals have been known to contribute to the aggravation of inflammatory diseases including asthma. We aimed to investigate the effects of mono-n-butyl phthalate (MnBP) which is one of the representing phthalates, and its antagonist in an eosinophilic asthma mouse model. BALB/c mice were sensitized by intraperitoneal injection of ovalbumin (OVA) with alum and followed by three nebulized OVA challenges. MnBP was administered through drinking water administration throughout the study period, and its antagonist, apigenin, was orally treated for 14 days before OVA challenges. Mice were assessed for airway hyperresponsiveness (AHR), differential cell count and type 2 cytokines in bronchoalveolar lavage fluid were measured in vivo. The expression of the aryl hydrocarbon receptor was markedly increased when MnBP was administered. MnBP treatment increased AHR, airway inflammatory cells (including eosinophils), and type 2 cytokines following OVA challenge compared to vehicle-treated mice. However, apigenin treatment reduced all asthma features, such as AHR, airway inflammation, type 2 cytokines, and the expression of the aryl hydrocarbon receptor in MnBP-augmented eosinophilic asthma. Our study suggests that MnBP exposure may increase the risk of eosinophilic inflammation, and apigenin treatment may be a potential therapy for asthma exacerbated by endocrine-disrupting chemicals.

Endocrine-disrupting chemical exposure augments neutrophilic inflammation in severe asthma through the autophagy pathway

Corticosteroid resistance, progressive lung function decline, and frequent asthma exacerbations are the hallmarks of neutrophilic asthma (NA). However, the potential contributors and their mechanisms of NA aggravation have not yet been fully clarified. This study was conducted to assess the precise mechanism and inflammatory effects of endocrine-disrupting chemicals using mono-n-butyl phthalate (MnBP) on an NA model. BALB/c mice from normal control and LPS/OVA-induced NA groups were treated with or without MnBP. The effects of MnBP on the airway epithelial cells (AECs), macrophages (Mφ), and neutrophils were investigated in vitro and in vivo. NA mice exposed to MnBP had significantly increased airway hyperresponsiveness, total and neutrophil cell counts in the bronchoalveolar lavage fluid, and the percentage of M1Mφ in the lung tissues compared to those non-exposed to MnBP. In in vitro study, MnBP induced the human neutrophil activation to release neutrophil DNA extracellular traps, Mφ polarizing toward M1Mφ, and AEC damage. Treatment with hydroxychloroquine (an autophagy inhibitor) reduced the effects of MnBP in vivo and in vitro. The results of our study suggest that MnBP exposure may increase the risk of neutrophilic inflammation in severe asthma and autophagy pathway-targeted therapeutics can help control MnBP-induced harmful effects in asthma.