Livestock farm particulate matter enhances airway inflammation in mice with or without allergic airway disease

Particulate matter in poultry house on poultry respiratory disease: a systematic review

Particulate matter (PM) is one of the essential environmental stressors for the poultry industry in the world. Given its large specific surface area, PM can adsorb and carry a variety of pollutants, including heavy metal ions, ammonia, and persistent organic pollutants such as pathogenic microorganisms. High concentrations of PM induce poultry respiratory inflammation and trigger various diseases. However, the pathogenic mechanism of PM in poultry houses on respiratory diseases has not been clarified due to its complexity and lack of accurate assays. In terms of pathogenesis, there are 3 ways to explain this phenomenon: Inhaled PM irritates the respiratory tract, decreases immune resistance, and causes a respiratory disease; respiratory tract irritation by compounds presents in PM; infections with pathogenic and non-pathogenic microorganisms attached to PM. The latter 2 modes of influence are more harmful. Specifically, PM can induce the respiratory disease through several toxic mechanisms, including ammonia ingestion and bioaccumulation, lung flora dysbiosis, oxidative stress, and metabolic disorders. Therefore, this review summarizes the characteristics of PM in the poultry house and the impact of poultry PM on respiratory disease and proposes potential pathogenic mechanisms.

Association of distance to swine concentrated animal feeding operations with immune-mediated diseases: An exploratory gene-environment study

BACKGROUND

Concentrated animal feeding operations (CAFOs) are a source of environmental pollution and have been associated with a variety of health outcomes. Immune-mediated diseases (IMD) are characterized by dysregulation of the normal immune response and, while they may be affected by gene and environmental factors, their association with living in proximity to a CAFO is unknown.

OBJECTIVES

We explored gene, environment, and gene-environment (GxE) relationships between IMD, CAFOs, and single nucleotide polymorphisms (SNPs) of prototypical xenobiotic response genes AHR, ARNT, and AHRR and prototypical immune response gene PTPN22.

METHODS

The exposure analysis cohort consisted of 6,464 participants who completed the Personalized Environment and Genes Study Health and Exposure Survey and a subset of 1,541 participants who were genotyped. We assessed the association between participants' residential proximity to a CAFO in gene, environment, and GxE models. We recombined individual associations in a transethnic model using METAL meta-analysis.

RESULTS

In White participants, ARNT SNP rs11204735 was associated with autoimmune diseases and rheumatoid arthritis (RA), and ARNT SNP rs1889740 was associated with RA. In a transethnic genetic analysis, ARNT SNPs rs11204735 and rs1889740 and PTPN22 SNP rs2476601 were associated with autoimmune diseases and RA. In participants living closer than one mile to a CAFO, the log-distance to a CAFO was associated with autoimmune diseases and RA. In a GxE interaction model, White participants with ARNT SNPs rs11204735 and rs1889740 living closer than eight miles to a CAFO had increased odds of RA and autoimmune diseases, respectively. The transethnic model revealed similar GxE interactions.

CONCLUSIONS

Our results suggest increased risk of autoimmune diseases and RA in those living in proximity to a CAFO and a potential role of the AHR-ARNT pathway in conferring risk. We also report the first association of ARNT SNPs rs11204735 and rs1889740 with RA. Our findings, if confirmed, could allow for novel genetically-targeted or other preventive approaches for certain IMD.

Characteristics of PM2.5 and Its Correlation with Feed, Manure and NH3 in a Pig-Fattening House

Fine particulate matter (PM), including PM_2.5 in pig houses, has received increasing attention due to the potential health risks associated with PM. At present, most studies have analyzed PM_2.5 in Chinese pig houses utilizing natural ventilation. These results, however, are strongly affected by the internal structure and regional environment, thus limiting their applicability to non-mechanically ventilated pig houses. This experiment was carried out in an environmentally controlled pig house. The animal feeding operation and manure management in the house were typical for Southwest China. To reduce the influence of various environmental factors on PM_2.5, the temperature and humidity in the house were maintained in a relatively stable state by using an environmental control system. The concentration of PM_2.5 in the pig house was monitored, while the biological contents and chemical composition of PM_2.5 were analyzed, and feed, manure, and dust particles were scanned using an electron microscope. Moreover, bacterial and fungal contents and some water-soluble ions in PM_2.5 were identified. The results showed that the concentration of PM_2.5 in the pig house was strongly affected by pig activity, and a phenomenon of forming secondary particles in the pig house was found, although the transformation intensity was low. The concentration of PM_2.5 had negative correlations of 0.27 and 0.18 with ammonia and hydrogen sulfide, respectively. Interestingly, a stronger correlation was observed between ammonia and hydrogen sulfide and ammonia and carbon dioxide concentrations (the concentration of ammonia had stronger positive correlations with hydrogen sulfide and carbon dioxide concentrations at +0.44 and +0.59, respectively). The main potential sources of PM_2.5 production were feed and manure. We speculate that manure could contribute to the broken, rough, and angular particles that formed the pig house PM_2.5 that easily adhered to other components.

Size-segregated physicochemical properties of inhalable particulate matter in a tunnel-ventilated layer house in China

This study investigated the physicochemical properties of the particles in a typical commercial laying hen barn in Southeast China. Mass concentrations and size distributions of the particulate matter (PM) and the key components (incl. organic carbon (OC), element carbon (EC), and the water-soluble inorganic ions (WSIIs)) were analyzed. The result shows that the mass concentrations of PM accumulated along with the airflow inside the house, with the total mass of the sampling particles increasing from 843.66 ± 160.74 μg/m³ at the center of the house to 1264.93 ± 285.70 μg/m³ at the place close to exhaust fans. The particles with the aerodynamic equivalent diameter, Dp > 9 μm, coarse particles (2.1 μm < Dp ≤ 9 μm), fine particles (Dp ≤ 2.1 μm) accounted for around 50%, 40%, and 10% of the total mass of the sampling particles, respectively. Mass closure analysis shows secondary inorganic ions (NH₄⁺, SO₄^2- and NO₃^-) were abundant in the fine-mode fraction and OC accounted for more than 40% of the coarse particles. Size distribution analysis shows that the three secondary inorganic ions were bimodally distributed, and the rest tested components were unimodally distributed. The ratios of OC/EC in fine particles were smaller than those in the coarse particles. The equivalent concentration of WSIIs indicated that fine particles were slightly acidic, and the large size particles were slightly alkaline. Knowledge gained from this study will lead to a better understanding of physicochemical properties, sources, and formation of PM.

Toxicological and microbiological characterization of cow stable dust

Exposure to farm environment has been shown to both protect from allergic diseases and increase the risk of respiratory syndromes. Mechanisms have been previously investigated by using farm dust extracts or specific components of dust. The use of authentic farm dust would better reflect the natural exposure. The aim of our study was to highlight the importance of proper assessment of the cow stable dust characteristics before conducting further investigations. For this purpose, we characterized microbiome and size distribution of unprocessed cow stable dust and its toxicological properties, as they have been often overlooked in search of protective factors. Stable dust samples from four Finnish dairy farms were collected by utilizing two different collection methods. Toxicological potential was analysed by stimulating co-cultures of lung epithelial and macrophage-like cells with dust. Size and mass distributions of airborne particles in the stables and bacterial and fungal microbiota of the dust were analysed. Stimulation with dust did not affect viability, but heightened oxidative stress responses and cytokine secretion, and slightly reduced the metabolic activity. There were a few differences in responses between farms, however, the differences were mainly in the intensity and not in the direction of the response. Cellular responses induced by dusts collected by different sampling methods did not differ substantially. Unprocessed stable dust samples showed relatively low direct toxicity but were able to trigger immune responses in studied cell model. This suggest that these dust collection methods could be utilized when investigating e.g. asthma-protective mechanisms.

Ex vivo innate responses to particulate matter from livestock farms in asthma patients and healthy individuals

BACKGROUND

Asthma patients suffer from periodic acute worsening of symptoms (i.e. loss of asthma control or exacerbations), triggered by a variety of exogenous stimuli. With the growing awareness that air pollutants impact respiratory diseases, we investigated whether particulate matter (PM) derived from various livestock farms (BioPM) differentially affected innate and oxidative stress responses in asthma and health.

METHODS

Peripheral blood mononuclear cells (PBMCs), collected from patients sequentially before and during loss of asthma control and from healthy individuals, were exposed to BioPM collected from chicken, goat and pig farms (1 and 5 μg/ml), with or without pre-treatment with antioxidants. Cytokine release and oxidative stress were assessed.

RESULTS

PBMCs produced IFNγ, IL-1β, IL-10 and TNFα upon stimulation with BioPM, with that from pig farms inducing the highest cytokine levels. Overall, cytokine production was irrespective of the presence or state of disease. However, PBMCs from stable asthma patients upon exposure to the three BioPM showed more extreme TNFα responses than those from healthy subjects. Furthermore, PBMCs obtained during loss of asthma control that were exposed to BioPM from pig farms showed enhanced IFNγ release as well as decreased oxidative stress levels upon pre-treatment with N-acetylcysteine (NAC) compared to stable disease. NAC, but not superoxide dismutase and catalase, also counteracted BioPM-induced cytokine release, indicating the importance of intracellular reactive oxygen species in the production of cytokines.

CONCLUSIONS

BioPM triggered enhanced pro-inflammatory responses by PBMCs from both healthy subjects and asthma patients, with those from patients during loss of asthma control showing increased susceptibility to BioPM from pig farms in particular.

Airborne particulate matter from goat farm increases acute allergic airway responses in mice

Background: Inhalation exposure to biological particulate matter (BioPM) from livestock farms may provoke exacerbations in subjects suffering from allergy and asthma. The aim of this study was to use a murine model of allergic asthma to determine the effect of BioPM derived from goat farm on airway allergic responses.Methods: Fine (<2.5 μm) BioPM was collected from an indoor goat stable. Female BALB/c mice were ovalbumin (OVA) sensitized and challenged with OVA or saline as control. The OVA and saline groups were divided in sub-groups and exposed intranasally to different concentrations (0, 0.9, 3, or 9 μg) of goat farm BioPM. Bronchoalveolar lavage fluid (BALF), blood and lung tissues were collected.Results: In saline-challenged mice, goat farm BioPM induced 1) a dose-dependent increase in neutrophils in BALF and 2) production of macrophage inflammatory protein-3a. In OVA-challenged mice, BioPM induced 1) inflammatory cells in BALF, 2) OVA-specific Immunoglobulin (Ig)G1, 3) airway mucus secretion-specific gene expression. RNAseq analysis of lungs indicates that neutrophil chemotaxis and oxidation-reduction processes were the representative genomic pathways in saline and OVA-challenged mice, respectively.Conclusions: A single exposure to goat farm BioPM enhanced airway inflammation in both saline and OVA-challenged allergic mice, with neutrophilic response as Th17 disorder and eosinophilic response as Th2 disorder indicative of the severity of allergic responses. Identification of the mode of action by which farm PM interacts with airway allergic pathways will be useful to design potential therapeutic approaches.