Inhalation Toxicology最新文献

Background: Lysosomal ion channels are proposed therapeutic targets for a number of diseases, including those driven by NLRP3 inflammasome-mediated inflammation. Here, the specific role of the lysosomal big conductance Ca²⁺-activated K⁺ (BK) channel was evaluated in a silica model of inflammation in murine macrophages. A specific-inhibitor of BK channel function, paxilline (PAX), and activators NS11021 and NS1619 were utilized to evaluate the role of lysosomal BK channel activity in silica-induced lysosomal membrane permeabilization (LMP) and NLRP3 inflammasome activation resulting in IL-1β release.

Methods: Murine macrophages were exposed in vitro to crystalline silica following pretreatment with BK channel inhibitors or activators and LMP, cell death, and IL-1β release were assessed. In addition, the effect of PAX treatment on silica-induced cytosolic K⁺ decrease was measured. Finally, the effects of BK channel modifiers on lysosomal pH, proteolytic activity, and cholesterol transport were also evaluated.

Results: PAX pretreatment significantly attenuated silica-induced cell death and IL-1β release. PAX caused an increase in lysosomal pH and decrease in lysosomal proteolytic activity. PAX also caused a significant accumulation of lysosomal cholesterol. BK channel activators NS11021 and NS1619 increased silica-induced cell death and IL-1β release. BK channel activation also caused a decrease in lysosomal pH and increase in lysosomal proteolytic function as well as a decrease in cholesterol accumulation.

Conclusion: Taken together, these results demonstrate that inhibiting lysosomal BK channel activity with PAX effectively reduced silica-induced cell death and IL-1β release. Blocking cytosolic K⁺ entry into the lysosome prevented LMP through the decrease of lysosomal acidification and proteolytic function and increase in lysosomal cholesterol.

Objective: In 1988, the Iraqi government used a range of chemical weapons (CWs) against the Iraqi Kurds of Halabja. Here, we aim to investigate the long-term health consequences in exposed survivors as they are not sufficiently studied.

Materials and methods: This was a retrospective study conducted from November 2019 to May 2020 assessing the health status of all exposed Halabja chemical attack survivors compared to non-exposed people from the same area.

Results and discussion: Two hundred thirty survivors and 240 non-exposed participants were enrolled in this study, with control participants matched to age, gender, and occupation. Among the survivors, females were more prevalent. The respiratory system was the most common single exposure route (83, 36.1%), with 138 (60%) of the survivors being exposed by multiple routes. The vast majority (88.7%) of survivors had activities of daily living (ADL) impairment. There was female predominance in mild and moderate cases, with more males in severe cases (p < 0.01). Respiratory and cardiac diseases were significantly more common in the survivors compared to the controls (p < 0.001). Survivors with multiple CW exposure routes had significantly higher rates of ADL impairment (p < 0.001) and cardiac disease, respiratory diseases, and miscarriage (p < 0.01), than those with a single exposure route.

Conclusion: In this study comparing CW survivors with a local control population, a single, high-dose exposure to CWs was associated with significant increases in chronic respiratory and cardiac conditions, in addition to high rates of ADL impairment. Similar studies are needed in other, more recent CW survivor cohorts.

Background: Paraquat (PQ) plays an important role in agricultural production due to its highly effective herbicidal effect. However, it has led to multiple organ failure in those who have been poisoned, with damage most notable in the lungs and ultimately leading to death. Because of little research has been performed at the genetic level, and therefore, the specific genetic changes caused by PQ exposure are unclear.Methods: Paraquat poisoning model was constructed in Sprague Dawley (SD) rats, and SD rats were randomly divided into Control group, paraquat (PQ) poisoning group and Anthrahydroquinone-2,6-disulfonate (AH₂QDS) treatment group. Then, the data was screened and quality controlled, compared with reference genes, optimized gene structure, enriched at the gene expression level, and finally, signal pathways with significantly different gene enrichment were screened.Results: This review reports on lung tissues from paraquat-intoxicated Sprague Dawley (SD) rats that were subjected to RNA-seq, the differentially expressed genes were mainly enriched in PI3K-AKT, cGMP-PKG, MAPK, Focal adhesion and other signaling pathways.Conclusion: The signaling pathways enriched with these differentially expressed genes are summarized, and the important mechanisms mediated through these pathways in acute lung injury during paraquat poisoning are outlined to identify important targets for AH₂QDS treatment of acute lung injury due to paraquat exposure, information that will be used to support a subsequent in-depth study on the mechanism of PQ action.

Sensory irritation is a health endpoint that serves as the critical effect basis for many occupational exposure limits (OELs). Schaper 1993 described a significant relationship with high correlation between the measured exposure concentration producing a 50% respiratory rate decrease (RD₅₀) in a standard rodent assay and the American Conference of Governmental Industrial Hygienists (ACGIH®) Threshold Limit Values (TLVs®) as time-weighted averages (TWAs) for airborne chemical irritants. The results demonstrated the potential use of the RD₅₀ values for deriving full-shift TWA OELs protective of irritant responses. However, there remains a need to develop a similar predictive model for deriving workplace short-term exposure limits (STELs) for sensory irritants. The aim of our study was to establish a model capable of correlating the relationship between RD₅₀ values and published STELs to prospectively derive short-term exposure OELs for sensory irritants. A National Toxicology Program (NTP) database that included chemicals with both an RD₅₀ and established STELs was used to fit several linear regression models. A strong correlation between RD₅₀s and STELs was identified, with a predictive equation of ln (STEL) (ppm) = 0.86 * ln (RD₅₀) (ppm) - 2.42 and an R² value of 0.75. This model supports the use of RD₅₀s to derive STELs for chemicals without existing exposure recommendations. Further, for data-poor sensory irritants, predicted RD₅₀ values from in silico quantitative structure activity relationship (QSAR) models can be used to derive STELs. Hence, in silico methods and statistical modeling can present a path forward for establishing reliable OELs and improving worker safety and health.

Objective: Due to recent increases in the use of vaping devices, there is a high demand for research addressing the respiratory health effects of vaping products. Given the constantly changing nature of the vaping market with new devices, flavors, metals, and other chemicals rapidly emerging, there is a need for inexpensive and highly adaptable vaping device exposure systems. Here, we describe the design and validation of a novel in vitro aerosol exposure system for toxicity testing of vaping devices.

Materials and methods: We developed an inexpensive, open-source in vitro vaping device exposure system that produces even deposition, can be adapted for different vaping devices, and allows for experiments to be performed under physiological conditions. The system was then validated with deposition testing and a representative exposure with human bronchial epithelial cells (hBECs).

Results: The Vaping Product Exposure System (VaPES) produced sufficient and uniform deposition for dose-response studies and was precise enough to observe biological responses to vaping exposures. VaPES was adapted to work with both pod and cartridge-based vaping devices.

Conclusion: We have designed and validated a novel vaping device exposure system that will eliminate the need to use high-cost commercial exposure systems, lowering the barrier to entry of physiologically relevant vaping studies.

The dominant road traffic particle sources are wear particles from the road and tire interface, and from vehicle brake pads. The aim of this work was to investigate the effect of road and brake wear particles on pulmonary function and biomarkers in isolated perfused rat lungs. Particles were sampled from the studded tire wear of three road pavements containing different rock materials in a road simulator; and from the wear of two brake pad materials using a pin-on-disk machine. Isolated rat lungs inhaled the coarse and fine fractions of the sampled particles resulting in an estimated total particle lung dose of 50 μg. The tidal volume (TV) was measured during the particle exposure and the following 50 min. Perfusate and BALF were analyzed for the cytokines TNF, CXCL1 and CCL3. The TV of lungs exposed to rock materials was significantly reduced after 25 min of exposure compared to the controls, for quartzite already after 4 min. The particles of the heavy-duty brake pads had no effect on the TV. Brake particles resulted in a significant elevation of CXCL1 in the perfusate. Brake particles showed significant elevations of all three measured cytokines, and quartzite showed a significant elevation of TNF in BALF. The study shows that the toxic effect on lungs exposed to airborne particles can be investigated using measurements of tidal volume. Furthermore, the study shows that the choice of rock material in road pavements has the potential to affect the toxicity of road wear PM10.

Objectives: An integrated in vitro inhalation approach was outlined to estimate potential adverse acute inhalation effects of aerosols from commercial nebulizer applications used for purposeful room conditioning such as disinfection, scenting or others. Aerosol characterization, exposure estimation and evaluation of acute biological effects by in vitro inhalation were included to generate dose-response data, allowing for determination of in vitro lowest observable adverse effect levels (LOAELs). Correlation of these to estimates of human lung deposition was included for quantitative in vitro to in vivo extrapolation approach (QIVIVE) for acute effects during human exposure.

Methods: To test the proposed approach, a case study was undertaken using two realistic test materials. An acute in vitro inhalation setup with air-liquid interface A549-cells in an optimized exposure situation (P.R.I.T.^® ExpoCube^®) was used to expose cells and analysis of relevant biological effects (viability, mitochondrial membrane potential, stress, IL-8 release) was carried out.

Results: The observed dose-responsive effects in a sub-toxic dose-range could be attributed to the main component of one test material and its presence in the aerosol phase of the nebulized material. QIVIVE resulted in a factor of at least 256 between the in vitro LOAEL and the estimated acute human lung exposure for this test material.

Conclusions: The case-study shows the value of the non-target in vitro inhalation testing approach especially in case of a lack of knowledge on complex product composition. It is expected that approaches like this will be of high value for product safety and environmental health in the future.