Ozone-induced enhancement of airway hyperreactivity in rhesus macaques: Effects of antioxidant treatment

Associations of ambient ozone exposure and CD4+ T cell levels with mortality among people living with HIV: An eight-year longitudinal study

There has been a consistent upward trend in ground-level ozone (O3) concentration in China. People living with HIV (PLWH) may be more vulnerable to the health impacts of O3 exposure due to their immunosuppressed state. This study aims to investigate the association between ambient O3 exposure and mortality among PLWH, as well as the potential exacerbating effects of a decreased CD4+ T cell level. Daily maximum 8-hour O3 concentrations were assigned to 7270 PLWH at a county level in Guangxi, China. Every 10-unit increase in ambient O3 concentration was associated with a significant rise in all-cause mortality ranging from 7.3 % to 28.7 % and a significant rise in AIDS-related mortality ranging from 8.4 % to 14.5 %. When PLWH had a higher CD4+ count (≥350 cells/μL), elevated O3 concentration was associated with increased blood CD4+ count at lag0 [percent change with 95 % confidence interval, 0.20(0.00, 0.40)], lag1 [0.26(0.06, 0.47)], and lag2 [0.23(0.03, 0.44)]; however, an opposite association was observed when CD4+ count was <350 cells/μL for half-year average [-2.45(-4.71, -0.14)] and yearly average [-3.42(-5.51, -1.29)] of O3 exposure. The association of O3 exposure with all-cause and AIDS-related mortality was more prominent among those with higher CD4+ count. Exploratory analysis revealed possible associations between O3 exposure and respiratory infections and clinical symptoms. These findings suggest potential synergistic effects between a compromised immune status and elevated O3 exposure levels on mortality risk among PLWH. Ambient O3 exposure should be considered as an emerging mortality risk factor for PLWH in the era of antiretroviral therapy, requiring further attention from researchers and healthcare professionals.

Air pollutants contribute to epithelial barrier dysfunction and allergic diseases

Air pollution is a global problem associated with various health conditions, causing elevated rates of morbidity and mortality. Major sources of air pollutants include industrial emissions, traffic-related pollutants, and household biomass combustion, in addition to indoor pollutants from chemicals and tobacco. Various types of air pollutants originate from both human activities and natural sources. These include particulate matter, pollen, greenhouse gases, and other harmful gases. Air pollution is linked to allergic diseases, including atopic dermatitis, allergic rhinitis, allergic conjunctivitis, food allergy, and bronchial asthma. These pollutants lead to epithelial barrier dysfunction, dysbiosis, and immune dysregulation. In addition, climate change and global warming may contribute to the exacerbation and the development of allergic diseases related to air pollutants. Epigenetic changes associated with air pollutants have also been connected to the onset of allergic diseases. Furthermore, these changes can be passed down through subsequent generations, causing a higher prevalence of allergic diseases in offspring. Modulation of the aryl hydrocarbon receptor could be a valuable strategy for alleviating air pollutant-induced epidermal barrier dysfunction and atopic dermatitis. A more effective approach to preventing allergic diseases triggered by air pollutants is to reduce exposure to them. Implementing public policies aimed at safeguarding individuals from air pollutant exposure may prove to be the most efficient solution. A pressing need exists for global policy initiatives that prioritize efforts to reduce the production of air pollutants.

"Air That Once Was Breath" Part 1: Wildfire-Smoke-Induced Mechanisms of Airway Inflammation - "Climate Change, Allergy and Immunology" Special IAAI Article Collection: Collegium Internationale Allergologicum Update 2023

BACKGROUND

Wildfires are a global concern due to their wide-ranging environmental, economic, and public health impacts. Climate change contributes to an increase in the frequency and intensity of wildfires making smoke exposure a more significant and recurring health concern for individuals with airway diseases. Some of the most prominent effects of wildfire smoke exposure are asthma exacerbations and allergic airway sensitization. Likely due to the delayed recognition of its health impacts in comparison with cigarette smoke and industrial or traffic-related air pollution, research on the composition, the mechanisms of toxicity, and the cellular/molecular pathways involved is poor or non-existent.

SUMMARY

This review discusses potential underlying pathological mechanisms of wildfire-smoke-related allergic airway disease and asthma. We focused on major gaps in understanding the role of wildfire smoke composition in the development of airway disease and the known and potential mechanisms involving cellular and molecular players of oxidative injury at the epithelial barrier in airway inflammation. We examine how PM2.5, VOCs, O3, endotoxin, microbes, and toxic gases may affect oxidative stress and inflammation in the respiratory mucosal barrier. We discuss the role of AhR in mediating smoke's effects in alarmin release and IL-17A production and how glucocorticoid responsiveness may be impaired by IL-17A-induced signaling and epigenetic changes leading to steroid-resistant severe airway inflammation.

KEY MESSAGE

Effective mitigation of wildfire-smoke-related respiratory health effects would require comprehensive research efforts aimed at a better understanding of the immune regulatory effects of wildfire smoke in respiratory health and disease.

Variation in infant rhesus monkeys' (Macaca mulatta) neutrophil-to-lymphocyte ratio is associated with environmental conditions, emotionality, and cortisol concentrations, and predicts disease-related outcomes

The neutrophil-to-lymphocyte ratio (NLR) is a predictor of morbidity for a variety of medical conditions, but little is known about how variation in NLR arises. We examined variation in this measure in a sample of 4577 infant rhesus monkeys (54.8 % female), who participated in the BioBehavioral Assessment program at the California National Primate Research Center at 3-4 months of age. Lower values for NLR were seen for animals reared indoors, for animals that were raised to be free of specific pathogens, and for males. In addition lower NLR was associated with higher stress values of cortisol and with greater emotionality in response to an acute stressor. Finally, lower NLR in infancy was associated with greater risk for developing airways hyperresponsiveness (a hallmark of asthma); with display of diarrhea up to 3.97 years later; and with greater viral load when infected with the simian immunodeficiency virus at a mean of 6.1 years of age. Infant NLR was a better predictor of viral load than was a contemporaneously obtained measure of NLR. Infant and adult values of NLR were only modestly correlated; one reason may be that the infant measure was obtained during stressful conditions and the adult measure was obtained under baseline conditions. We propose that NLR is an integrated outcome measure reflecting organization and interaction of stress-response and immune systems. As such, assessment of NLR under conditions of stress may be a particularly useful marker of individual differences in morbidity, especially for conditions in which stress plays an important role, as in asthma, diarrhea/colitis, and AIDS.

Causal effect of PM1 on morbidity of cause-specific respiratory diseases based on a negative control exposure

BACKGROUND

Extensive studies have linked PM_2.5 and PM₁₀ with respiratory diseases (RD). However, few is known about causal association between PM₁ and morbidity of RD. We aimed to assess the causal effects of PM₁ on cause-specific RD.

METHODS

Hospital admission data were obtained for RD during 2014 and 2019 in Beijing, China. Negative control exposure and extreme gradient boosting with SHapley Additive exPlanation was used to explore the causality and contribution between PM₁ and RD. Stratified analysis by gender, age, and season was conducted.

RESULTS

A total of 1,183,591 admissions for RD were recorded. Per interquartile range (28 μg/m³) uptick in concentration of PM₁ corresponded to a 3.08% [95% confidence interval (CI): 1.66%-4.52%] increment in morbidity of total RD. And that was 4.47% (95% CI: 2.46%-6.52%) and 0.15% (95% CI: 1.44%-1.78%), for COPD and asthma, respectively. Significantly positive causal associations were observed for PM₁ with total RD and COPD. Females and the elderly had higher effects on total RD, COPD, and asthma only in the warm months (Z = 3.03, P = 0.002; Z = 4.01, P < 0.001; Z = 3.92, P < 0.001; Z = 2.11, P = 0.035; Z = 2.44, P = 0.015). Contribution of PM₁ ranked first, second and second for total RD, COPD, and asthma among air pollutants.

CONCLUSION

PM₁ was causally associated with increased morbidity of total RD and COPD, but not causally associated with asthma. Females and the elderly were more vulnerable to PM₁-associated effects on RD.

Ambient ozone, and urban PM2.5 co-exposure, aggravate allergic asthma via transient receptor potential vanilloid 1-mediated neurogenic inflammation

Allergic asthma is the most common pulmonary inflammatory disease, and epidemiological studies have revealed that PM_2.5 or ambient ozone (O₃) exposure contribute to the higher prevalence of allergic asthma. Current experimental evidence focus principally on the pathogenic effect of exposure to a single air pollutant, ignoring the possible synergistic effect of combined exposure to a mix of these pollutants, which is a more realistic scenario. In this study, allergic mice and a nociceptor antagonist were used to explore the mechanisms of co-exposure to these two important air pollutants. Compared with exposure to either PM_2.5 or O₃, combined exposure to both greatly aggravated allergic asthma in a dose dependent manner, including increased airway hyperresponsiveness, goblet cell metaplasia, more severe airway inflammation and higher oxidative stress levels. In addition, co-exposure in the allergic mice resulted in elevation of the expression of transient receptor potential vanilloid 1 (TRPV1), and of the production of substance P (SP), which exacerbated lung inflammation by neurogenic inflammation. TRPV1 antagonist (capsazepine, CPZ) treatment for the co-exposed allergic mice, markedly attenuated TRPV1 expression and SP release, and reduced airway inflammation and oxidative damage, further alleviating airway hyperresponsiveness. We conclude that neuro-immune interactions might be involved in PM_2.5 and O₃ co-exposure aggravated allergic asthma.

Sea spray aerosols intervening phospholipids ozonolysis at the air-water interface

With more than half of the world's population lives along the coast and in its vicinity, the sea spray aerosols (SSAs) with respect to respiratory system impact has attracted increasing attention. In this paper, ozonolysis of model lung phospholipids intervened by salt cations in SSAs at air-water interface was investigated using acoustic levitation-nano-electrospray ionization-mass spectrometry (AL-nano-ESI-MS). The cation species facilitated the interfacial ozonolysis of phospholipids, and this increased ozonolysis showed a dependence on the concentration of salt cations. The charge number and ion radius of salt cations were also investigated, and the times of increased efficiency for phospholipids ozonolysis at the air-water interface were higher with more charge numbers or lower ion radius. The mechanism study revealed that the electrostatic interaction between the electronegative headgroup of phospholipids and the cations disturbed the packing of phospholipids, and resulted in oleyl chains more vulnerable with ozone. Finally, aerosolization of the salt-dominated artificial seawater and real seawater revealed a significant increase on ozonolysis of phospholipid intervened by salt cations. These results reveal SSAs intervening phospholipids interfacial reaction at the molecule level, which will be beneficial to gain the knowledge of the negative health effect concerning the components involved in SSAs.

A Novel Nonhuman Primate Model of Nonatopic Asthma

Nonhuman primate models have an essential role in understanding progressive respiratory disease pathogenesis. Immune and physiologic parameters in the nonhuman primate closely reflect the complexity of human systems and provide an exceptional translational impact for the investigation of the mucosal immune changes in response to environmental exposures. This potential warrants the development of novel models that will clarify the interaction of respiratory disease and the inhalable environment and the potential of novel therapies to alleviate the untoward results of these interactions. Nonhuman primate models of asthma can be spontaneous, induced, or experimentally manipulated by various exposures. Here we describe a model of exacerbation of airway hyperreactivity induced by exposure to an air pollutant, ozone, in a cohort of young adult asthmatic rhesus macaques.

Knowledge of Biobehavioral Organization Can Facilitate Better Science: A Review of the BioBehavioral Assessment Program at the California National Primate Research Center

Animals vary on intrinsic characteristics such as temperament and stress responsiveness, and this information can be useful to experimentalists for identifying more homogeneous subsets of animals that show consistency in risk for a particular research outcome. Such information can also be useful for balancing experimental groups, ensuring animals within an experiment have similar characteristics. In this review, we describe the BioBehavioral Assessment Program at the California National Primate Research Center, which, since its inception in 2001, has been providing quantitative information on intrinsic characteristics to scientists for subject selection and balancing, and to colony management staff for management purposes. We describe the program and review studies relating to asthma, autism, behavioral inhibition, etc., where the BBA Program was used to select animals. We also review our work, showing that factors such as rearing, ketamine exposure, and prenatal experience can affect biobehavioral organization in ways that some investigators might want to control for in their studies. Attention to intrinsic characteristics of subject populations is consistent with the growing interest in precision medicine and can lead to a reduction in animal numbers, savings in time and money for investigators, and reduced distress for the animals.

Assessment of a Small Molecule Synthetic Lignan in Enhancing Oxidative Balance and Decreasing Lipid Accumulation in Human Retinal Pigment Epithelia

Visual function depends on the intimate structural, functional and metabolic interactions between the retinal pigment epithelium (RPE) and the neural retina. The daily phagocytosis of the photoreceptor outer segment tips by the overlaying RPE provides essential nutrients for the RPE itself and photoreceptors through intricate metabolic synergy. Age-related retinal changes are often characterized by metabolic dysregulation contributing to increased lipid accumulation and peroxidation as well as the release of proinflammatory cytokines. LGM2605 is a synthetic lignan secoisolariciresinol diglucoside (SDG) with free radical scavenging, antioxidant and anti-inflammatory properties demonstrated in diverse in vitro and in vivo inflammatory disease models. In these studies, we tested the hypothesis that LGM2605 may be an attractive small-scale therapeutic that protects RPE against inflammation and restores its metabolic capacity under lipid overload. Using an in vitro model in which loss of the autophagy protein, LC3B, results in defective phagosome degradation and metabolic dysregulation, we show that lipid overload results in increased gasdermin cleavage, IL-1 β release, lipid accumulation and decreased oxidative capacity. The addition of LGM2605 resulted in enhanced mitochondrial capacity, decreased lipid accumulation and amelioration of IL-1 β release in a model of defective lipid homeostasis. Collectively, these studies suggest that lipid overload decreases mitochondrial function and increases the inflammatory response, with LGM2605 acting as a protective agent.

Ozone-Induced Oxidative Stress, Neutrophilic Airway Inflammation, and Glucocorticoid Resistance in Asthma

Despite recent advances in using biologicals that target Th2 pathways, glucocorticoids form the mainstay of asthma treatment. Asthma morbidity and mortality remain high due to the wide variability of treatment responsiveness and complex clinical phenotypes driven by distinct underlying mechanisms. Emerging evidence suggests that inhalation of the toxic air pollutant, ozone, worsens asthma by impairing glucocorticoid responsiveness. This review discusses the role of oxidative stress in glucocorticoid resistance in asthma. The underlying mechanisms point to a central role of oxidative stress pathways. The primary data source for this review consisted of peer-reviewed publications on the impact of ozone on airway inflammation and glucocorticoid responsiveness indexed in PubMed. Our main search strategy focused on cross-referencing "asthma and glucocorticoid resistance" against "ozone, oxidative stress, alarmins, innate lymphoid, NK and γδ T cells, dendritic cells and alveolar type II epithelial cells, glucocorticoid receptor and transcription factors". Recent work was placed in the context from articles in the last 10 years and older seminal research papers and comprehensive reviews. We excluded papers that did not focus on respiratory injury in the setting of oxidative stress. The pathways discussed here have however wide clinical implications to pathologies associated with inflammation and oxidative stress and in which glucocorticoid treatment is essential.

Air pollutants and development of interstitial lung disease in patients with connective tissue disease: a population-based case-control study in Taiwan

OBJECTIVE

The aim of this study was to assess the association between air pollutant exposure and interstitial lung disease (ILD) in patients with connective tissue diseases (CTDs).

SETTING

A nationwide, population-based, matched case-control study in Taiwan.

PARTICIPANTS

Using the 1997-2013 Taiwanese National Health Insurance Research Database, we identified patients with newly diagnosed CTD during 2001-2013, including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), systemic sclerosis (SSc), dermatomyositis (DMtis)/polymyositis (PM) and primary Sjögren's syndrome (pSS).

PRIMARY AND SECONDARY OUTCOME MEASURES

Patients with newly diagnosed ILD during 2012-2013 were identified as ILD cases, and selected patients with CTD without ILD matching (1:4) the CTD cases for CTD diagnosis, age, gender, disease duration and year of ILD diagnosis date were identified as non-ILD controls. Data of hourly level of air pollutants 1 year before the index date were obtained from the Taiwan Environmental Protection Agency. The association between ILD and air pollutant exposure was evaluated using logistic regression analysis shown as adjusted ORs (aORs) with 95% CIs after adjusting for potential confounders.

RESULTS

We identified 505 newly diagnosed CTD-ILD patients, including 82 with SLE, 210 with RA, 47 with SSc, 44 with DMtis/PM and 122 with pSS. Ozone (O₃) exposure (per 10 ppb) was associated with a decreased ILD risk in patients with CTD (aOR, 0.51; 95% CI, 0.33 to 0.79) after adjusting for potential confounders.

CONCLUSIONS

A previously unrecognised inverse correlation was found between O₃ exposure and ILD in patients with RA and SSc. Further studies are warranted to explore the underlying mechanisms.

Synthetic Secoisolariciresinol Diglucoside Attenuates Established Pain, Oxidative Stress and Neuroinflammation in a Rodent Model of Painful Radiculopathy

Painful cervical radiculopathy is characterized by chronic neuroinflammation that lowers endogenous antioxidant responses leading to the development of oxidative stress and pain after neural trauma. Therefore, antioxidants such as secoisolariciresinol diglucoside (SDG), that promote antioxidant signaling and reduce oxidative damage may also provide pain relief. This study investigated if repeated systemic administration of synthetic SDG after a painful root compression reduces the established pain, oxidative stress and spinal glial activation that are typically evident. SDG was administered on days 1-3 after compression and the extent of oxidative damage in the dorsal root ganglia (DRG) and spinal cord was measured at day 7 using the oxidative stress markers 8-hydroxguanosine (8-OHG) and nitrotyrosine. Spinal microglial and astrocytic activation were also separately evaluated at day 7 after compression. In addition to reducing pain, SDG treatment reduced both spinal 8-OHG and nitrotyrosine, as well as peripheral 8-OHG in the DRG. Moreover, SDG selectively reduced glial activation by decreasing the extent of astrocytic but not microglial activation. These findings suggest that synthetic SDG may attenuate existing radicular pain by suppressing the oxidative stress and astrocytic activation that develop after painful injury, possibly identifying it as a potent therapeutic for painful radiculopathies.

L. Migliaccio C, Buford M, Ballou S, Migliaccio CT. Sustained Effects on Lung Function in Community Members Following Exposure to Hazardous PM2.5 Levels from Wildfire Smoke

Extreme wildfire events are becoming more common and while the immediate risks of particulate exposures to susceptible populations (i.e., elderly, asthmatics) are appreciated, the long-term health effects are not known. In 2017, the Seeley Lake (SL), MT area experienced unprecedented levels of wildfire smoke from July 31 to September 18, with a daily average of 220.9 μg/m³. The aim of this study was to conduct health assessments in the community and evaluate potential adverse health effects. The study resulted in the recruitment of a cohort (n = 95, average age: 63 years), for a rapid response screening activity following the wildland fire event, and two follow-up visits in 2018 and 2019. Analysis of spirometry data found a significant decrease in lung function (FEV₁/FVC ratio: forced expiratory volume in first second/forced vital capacity) and a more than doubling of participants that fell below the lower limit of normal (10.2% in 2017 to 45.9% in 2018) one year following the wildfire event, and remained decreased two years (33.9%) post exposure. In addition, observed FEV₁ was significantly lower than predicted values. These findings suggest that wildfire smoke can have long-lasting effects on human health. As wildfires continue to increase both here and globally, understanding the health implications is vital to understanding the respiratory impacts of these events as well as developing public health strategies to mitigate the effects.