The transcriptomic signature of respiratory sensitizers using an alveolar model.

Environmental contaminants are ubiquitous in the air we breathe and can potentially cause adverse immunological outcomes such as respiratory sensitization, a type of immune-driven allergic response in the lungs. Wood dust, latex, pet dander, oils, fragrances, paints, and glues have all been implicated as possible respiratory sensitizers. With the increased incidence of exposure to chemical mixtures and the rapid production of novel materials, it is paramount that testing regimes accounting for sensitization are incorporated into development cycles. However, no validated assay exists that is universally accepted to measure a substance's respiratory sensitizing potential. The lungs comprise various cell types and regions where sensitization can occur, with the gas-exchange interface being especially important due to implications for overall lung function. As such, an assay that can mimic the alveolar compartment and assess sensitization would be an important advance for inhalation toxicology. Some such models are under development, but in-depth transcriptomic analyses have yet to be reported. Understanding the transcriptome after sensitizer exposure would greatly advance hazard assessment and sustainability. We tested two known sensitizers (i.e., isophorone diisocyanate and ethylenediamine) and two known non-sensitizers (i.e., chlorobenzene and dimethylformamide). RNA sequencing was performed in our in vitro alveolar model, consisting of a 3D co-culture of epithelial, macrophage, and dendritic cells. Sensitizers were readily distinguishable from non-sensitizers by principal component analysis. However, few differentially regulated genes were common across all pair-wise comparisons (i.e., upregulation of genes SOX9, UACA, CCDC88A, FOSL1, KIF20B). While the model utilized in this study can differentiate the sensitizers from the non-sensitizers tested, further studies will be required to robustly identify critical pathways inducing respiratory sensitization.

Health burden of sugarcane burning on agricultural workers and nearby communities.

Sugarcane is the most widely cultivated crop in the world, with equatorial developing nations performing most of this agriculture. Burning sugarcane is a common practice to facilitate harvest, producing extremely high volumes of respirable particulate matter in the process. These emissions are known to have deleterious effects on agricultural workers and nearby communities, but the extent of this exposure and potential toxicity remain poorly characterized. As the epidemicof chronic kidney disease of an unknown etiology (CKDu) and its associated mortality continue to increase along with respiratory distress, there is an urgent need to investigate the causes, determine viable interventions to mitigate disease andimprove outcomes for groups experiencing disproportionate impact. The goal of this review is to establish the state of available literature, summarize what is known in terms of human health risk, and provide recommendations for what areas should be prioritized in research.

Peripheral (lung-to-brain) exposure to diesel particulate matter induces oxidative stress and increased markers for systemic inflammation.

Combustion-derived air pollution is a complex environmental toxicant that has become a global health concern due to urbanization. Air pollution contains pro-inflammatory stimulants such as fine and ultrafine particulate matter, gases, volatile organic compounds, and metals. This study is focused on the particulate phase, which has been shown to induce systemic inflammation after chronic exposure due to its ability to travel to the lower airway, resulting in the activation of local immune cell populations, releasing acute phase reactants to mitigate ongoing inflammation. The systemic response is a potential mechanism for the co-morbidity associated with regions with high pollution and neuropathology. We exposed diesel particulate matter (DPM) to a pulmonary cell-derived in vitro model where macrophages mimic the diffusion of cytokines into the peripheral circulation to microglia. Alveolar macrophages (transformed U937) were inoculated with resuspended DPM in an acute exposure (24-h incubation) and analyzed for MCP-1 expression and acute phase reactants (IL-1ß, IL-6, IL-8, and TNF-α). Post-exposure serum was collected and filtered from cultured alveolar macrophages, introduced to a healthy culture of microglial cells (HMC3), and measured for neurotoxic cytokines, oxidative stress, and pattern recognition receptors. After DPM exposure, the macrophages significantly upregulated all measured acute phase reactants, increased H2O2 production, and increased MCP-1 expression. After collection and filtration to remove excess particulates, microglia cells were incubated with the collected serum for 48 h to allow for cytokine diffusion between the periphery of microglia. Microglia significantly upregulated IL-6, IL-8, and oxidative stress with a moderate increase in IL-1ß and TNF-α. As a marker required for signaling tissue damage, CD14 indicated that compared to direct inoculation of DPM, peripheral exposure resulted in the potent activation of microglia cells. The specificity and potency of the response have implications for neuropathology through lung-to-brain mechanisms after inhalation of environmental pollutants.

Freedom and loneliness: dementia caregiver experiences of the nursing home transition.

BACKGROUND: the transition to nursing home care has previously been linked to negative outcomes for spousal caregivers of persons with dementia (PwD). However, little is known about the experience or trajectory of loneliness in spousal caregivers during this time. OBJECTIVES: to explore experiences of loneliness in caregivers during the nursing home admission of their spouse or partner with dementia. METHODS: semi-structured interviews were conducted with 11 individuals living in Ireland between Oct 2020 and June 2021, who were married to/partnered with a PwD who had, in the past 7 years, moved to full-time nursing home care. Data were collected and analysed using a deductive qualitative analytic strategy in the grounded theory tradition. RESULTS: data were interpreted in the context of Weiss' typology of social and emotional loneliness and indicated that social loneliness increased for many at the point of diagnosis, decreasing somewhat after the transition, while emotional loneliness increased across the transition. Data were used to refine an existing synthesised model of loneliness, providing an updated model of the causes and contexts of loneliness. CONCLUSIONS: the transition to nursing home care differentially affects loneliness subtypes. Results have implications for other transitions, which should be assessed in terms of various subtypes of loneliness. Our refined theoretical synthesis model of loneliness also warrants further evaluation.

An In Vitro Alveolar Model Allows for the Rapid Assessment of Particles for Respiratory Sensitization Potential.

Dust, both industrial and household, contains particulates that can reach the most distal aspects of the lung. Silica and nickel compounds are two such particulates and have known profiles of poor health outcomes. While silica is well-characterized, nickel compounds still need to be fully understood for their potential to cause long-term immune responses in the lungs. To assess these hazards and decrease animal numbers used in testing, investigations that lead to verifiable in vitro methods are needed. To understand the implications of these two compounds reaching the distal aspect of the lungs, the alveoli, an architecturally relevant alveolar model consisting of epithelial cells, macrophages, and dendritic cells in a maintained submerged system, was utilized for high throughput testing. Exposures include crystalline silica (SiO2) and nickel oxide (NiO). The endpoints measured included mitochondrial reactive oxygen species and cytostructural changes assessed via confocal laser scanning microscopy; cell morphology evaluated via scanning electron microscopy; biochemical reactions assessed via protein arrays; transcriptome assessed via gene arrays, and cell surface activation markers evaluated via flow cytometry. The results showed that, compared to untreated cultures, NiO increased markers for dendritic cell activation, trafficking, and antigen presentation; oxidative stress and cytoskeletal changes, and gene and cytokine expression of neutrophil and other leukocyte chemoattractants. The chemokines and cytokines CCL3, CCL7, CXCL5, IL-6, and IL-8 were identified as potential biomarkers of respiratory sensitization.

The impact of an occupational therapy group cognitive rehabilitation program for people with dementia.

INTRODUCTION: This study was conducted to examine the impact of a group cognitive rehabilitation program for people with dementia on everyday memory function and quality of life. METHODS: Participants included in the study were community-dwelling adults with a diagnosis of dementia. The intervention was a 5-week occupational therapy lead group cognitive rehabilitation program delivered once a week for 1.5 h. Outcome measures included standardised memory tests, subjective everyday memory function and quality of life ratings. The measures were completed at baseline, post-intervention and 3-month post-intervention. RESULTS: Outcome measures were completed with 58 participants. Statistically significant improvements in standardised memory scores were noted following the intervention. Similarly, self-rated everyday memory function and quality of life scores significantly improved following the intervention. All standardised scores and subjective ratings were maintained at 3-month follow-up. CONCLUSION: Group-based cognitive rehabilitation programs can positively impact the quality of life and everyday memory function among people with dementia.

Encouraging lifestyle behaviour change in mild cognitive impairment patients: development of appropriate educational material.

OBJECTIVES: A healthy lifestyle may help maintain cognitive function and reduce the risk of developing dementia. This study employed a focus group approach in order to gain insight into opinions of mild cognitive impairment (MCI) patients, caregivers (CG) and health professionals (HP) regarding lifestyle and its relationship with cognition. The qualitative data were used to design, develop and pilot test educational material (EM) to help encourage lifestyle behaviour change. METHOD: Data gathering phase: structured interviews were conducted with HP (n = 10), and focus groups with MCI patients (n = 24) and CG (n = 12). EM was developed and pilot tested with a new group of MCI patients (n = 21) and CG (n = 6). RESULTS: HP alluded to the lack of clinical trial evidence for a lifestyle and MCI risk link. Although they felt that lifestyle modifications should be recommended to MCI patients, they appeared hesitant in communicating this information and discussions were often patient-driven. MCI patients lacked awareness of the lifestyle cognition link. Participants preferred EM to be concise, eye-catching and in written format, with personal delivery of information favoured. Most pilot testers approved of the EM but were heterogeneous in terms of lifestyle, willingness to change and support needed to change. CONCLUSION: MCI patients need to be made more aware of the importance of lifestyle for cognition. EM such as those developed here, which are specifically tailored for this population would be valuable for HP who, currently, appear reticent in initiating lifestyle-related discussions. Following further evaluation, the EM could be used in health promotion activities targeting MCI patients.

Human lung cell models to study aerosol delivery - considerations for model design and development.

Human lung tissue models range from simple monolayer cultures to more advanced three-dimensional co-cultures. Each model system can address the interactions of different types of aerosols and the choice of the model and the mode of aerosol exposure depends on the relevant scenario, such as adverse outcomes and endpoints of interest. This review focuses on the functional, as well as structural, aspects of lung tissue from the upper airway to the distal alveolar compartments as this information is relevant for the design of a model as well as how the aerosol properties determine the interfacial properties with the respiratory wall. The most important aspects on how to design lung models are summarized with a focus on (i) choice of appropriate scaffold, (ii) selection of cell types for healthy and diseased lung models, (iii) use of culture condition and assembly, (iv) aerosol exposure methods, and (v) endpoints and verification process. Finally, remaining challenges and future directions in this field are discussed.

An in vitro alveolar model allows for the rapid assessment of chemical respiratory sensitization with modifiable biomarker endpoints.

Diisocyanates are commonly used in polyurethanes where use includes industrial, commercial, and residential applications and can exist as respirable contaminants. These respirable contaminants exist in the air we breathe. Yet, there is no rapid assay available to test for potential respiratory sensitizers. To assess these hazards, as well as to decrease animal numbers used in testing, investigations that lead to verifiable in vitro methods are needed. We describe an easy, reliable, verified cell culture model that can be adopted by any lab capable of performing molecular toxicology. The architecturally relevant alveolar model consists of epithelial cells, macrophage cells, and dendritic cells in a simply maintained submerged system ideal for high-throughput testing. Exposures to contaminants that verify biomarker identification include a known pulmonary sensitizer (isophorone diisocyanate) and a positive control for cellular activation (phorbol 12-myristate 13-acetate/ionomycin). The mitochondrial reactive oxygen species generation and cytostructural changes were assessed with confocal laser scanning microscopy; cell morphology was assessed with scanning electron microscopy; biochemical reactions were assessed via protein arrays; genetic alterations were assessed via gene arrays; and cell surface activation markers were assessed via flow cytometry. Results showed that compared to untreated cultures, isophorone diisocyanate increased markers for dendritic cell activation, trafficking, and antigen presentation; number and length of dendritic protrusions; oxidative stress; and genetic and cytokine expression of neutrophil chemoattractants. The chemokines and cytokines CCL7, CXCL5, IL-6, and IL-8 were identified as biomarkers indicative of respiratory sensitization. By including multiple methods to assess endpoints, the in vitro model described can serve as a high-throughput assay to identify substances which may lead to respiratory sensitization.

Synergistic cytotoxicity of bromoacetic acid and three emerging bromophenolic disinfection byproducts against human intestinal and neuronal cells.

Halogenated disinfection byproducts (halo-DBPs) are drinking water contaminants of great public health concern. Nine haloaliphatic DBPs have been regulated by the U.S. Environmental Protection Agency and various halophenolic compounds have been identified as emerging DBPs. In this study, we evaluated the cytotoxic interactions of the regulated bromoacetic acid and three emerging bromophenolic DBPs, i.e., 2,4,6-tribromophenol, 3,5-dibromo-4-hydroxybenzoic acid, and 3,5-dibromo-4-hydroxybenzaldehyde. Cytotoxicity was measured for each DBP individually as well as each of their mixtures using in vitro human epithelial colorectal adenocarcinoma (Caco-2) and neuroblastoma (SH-SY5Y) cells. Concentration addition (CA) model and isobolographic analysis were employed to characterize the interactions among the DBPs. Our results show that the cytotoxicity of four bromo-DBPs against both cell-types followed the descending rank order of bromoacetic acid > 2,4,6-tribromophenol > 3,5-dibromo-4-hydroxybenzaldehyde > 3,5-dibromo-4-hydroxybenzoic acid. Compared with the toxicity data in literature, our finding that bromoacetic acid showed higher cytotoxicity than bromophenolic DBPs was consistent with the results from Chinese hamster ovary cells (a commonly used in vitro model of DBP toxicological studies); but different from the results obtained from in vivo biological models. Significantly, with CA model prediction, we found that mixtures of four bromo-DBPs exhibited synergistic cytotoxic effects on both human cell types. Isobolographic analysis of binary DBP mixtures revealed that, for Caco-2 cells, bromoacetic acid, 2,4,6-tribromophenol, and 3,5-dibromo-4-hydroxybenzoic acid induced synergism; for SH-SY5Y cells, bromoacetic acid induced synergism with all three bromophenolic DBPs. The production of reactive oxidative species (ROS) induced by DBP mixtures could be an important reason for the synergistic cytotoxicity.