Activity of nitric oxide synthase isoforms in acute brain oxidative damage induced by ozone exposure

Pre-pregnancy ozone and ultrafine particulate matter exposure during second year of life associated with decreased cognitive and adaptive functioning at aged 2-5 years

BACKGROUND

This study sought to investigate the association of prenatal and early life exposure to a mixture of air pollutants on cognitive and adaptive outcomes separately in children with or without autism spectrum disorder (ASD).

METHODS

Utilizing data from the CHARGE case-control study (birth years: 2000-2016), we predicted daily air concentrations of NO2, O3, and particulate matter <0.1 μm (PM0.1), between 0.1 and 2.5 μm (PM0.1-2.5), and between 2.5 and 10 μm (PM2.5-10) using chemical transport models with ground-based monitor adjustments. Exposures were evaluated for pre-pregnancy, each trimester, and the first two years of life. Individual and combined effects of pollutants were assessed with Vineland Adaptive Behavior Scales (VABS) and Mullen Scales of Early Learning (MSEL), separately for children with ASD (n = 660) and children without ASD (typically developing (TD) and developmentally delayed (DD) combined; n = 753) using hierarchical Bayesian Kernel Machine Regression (BKMR) models with three groups: PM size fractions (PM0.1, PM0.1-2.5, PM2.5-10), NO2, and O3.

RESULTS

Pre-pregnancy Ozone was strongly negatively associated with all scores in the non-ASD group (group posterior inclusion probability (gPIP) = 0.83-1.00). The PM group during year 2 was also strongly negatively associated with all scores in the non-ASD group (gPIP = 0.59-0.93), with PM0.1 driving the group association (conditional PIP (cPIP) = 0.73-0.96). Weaker and less consistent associations were observed between PM0.1-2.5 during pre-pregnancy and ozone during year 1 and VABS scores in the ASD group.

CONCLUSIONS

These findings prompt further investigation into ozone and ultrafine PM as potential environmental risk factors for neurodevelopment.

Ozone-induced neurotoxicity: In vitro and in vivo evidence

Together with cities in higher-income nations, it is anticipated that the real global ozone is rising in densely populated areas of Asia and Africa. This review aims to discuss the possible neurotoxic pollutants and ozone-induced neurotoxicity: in vitro and in vivo, along with possible biomarkers to assess ozone-related oxidative stress. As a methodical and scientific strategy for hazard identification and risk characterization of human chemical exposures, toxicological risk assessment is increasingly being implemented. While traditional methods are followed by in vitro toxicology, cell culture techniques are being investigated in modern toxicology. In both human and rodent models, aging makes the olfactory circuitry vulnerable to spreading immunological responses from the periphery to the brain because it lacks the blood-brain barrier. The ozone toxicity is elusive as it shows ventral and dorsal root injury cases even in the milder dose. Its potential toxicity should be disclosed to understand further the clear mechanism insights of how it acts in cellular aspects. Human epidemiological research has confirmed the conclusions that prenatal and postnatal exposure to high levels of air pollution are linked to behavioral alterations in offspring. O3 also enhances blood circulation. It has antibacterial action, which may have an impact on the gut microbiota. It also activates immunological, anti-inflammatory, proteasome, and growth factor signaling Prolonged O3 exposure causes oxidative damage to plasma proteins and lipids and damages the structural and functional integrity of the mitochondria. Finally, various studies need to be conducted to identify the potential biomarkers associated with ozone and the brain.

Long-term exposure to ambient air pollutants and their interaction with physical activity on insomnia: A prospective cohort study

Exposure to air pollution or lack of physical activity (PA) increases the risk of insomnia. However, evidence on joint exposure to air pollutants is limited, and the interaction of joint air pollutants and PA on insomnia is unknown. This prospective cohort study included 40,315 participants with related data from the UK Biobank, which recruited participants from 2006 to 2010. Insomnia was assessed by self-reported symptoms. The annual average air pollutant concentrations of particulate matter (PM_2.5, PM₁₀), nitrogen oxides (NO₂, NO_X), sulfur dioxide (SO₂) and carbon monoxide (CO) were calculated based on participants' addresses. We applied a weighted Cox regression model to evaluate the correlation between air pollutants and insomnia and newly proposed an air pollution score to assess joint air pollutants effect using a weighted concentration summation after obtaining the weights of each pollutant in the Weighted-quantile sum regression. With a median follow-up of 8.7 years, 8511 participants developed insomnia. For each 10 μg/m³ increase in NO₂, NO_X, PM₁₀, SO₂, the average hazard ratios (AHRs) and 95% confidence interval (CI) of insomnia were 1.10 (1.06, 1.14), 1.06 (1.04, 1.08), 1.35 (1.25, 1.45) and 2.58 (2.31, 2.89), respectively; For each 5 μg/m³ increase in PM_2.5 and each 1 mg/m³ increase in CO, the corresponding AHRs (95%CI) were 1.27 (1.21, 1.34) and 1.83 (1.10, 3.04), respectively. The AHR (95%CI) for insomnia associated with per interquartile range (IQR) increase in air pollution scores were 1.20 (1.15, 1.23). In addition, potential interactions were examined by setting cross-product terms of air pollution score with PA in the models. We observed an interaction between air pollution scores and PA (P = 0.032). The associations between joint air pollutants and insomnia were attenuated among participants with higher PA. Our study provides evidence on developing strategies for improving healthy sleep by promoting PA and reducing air pollution.

Prenatal Exposure to Air Pollution and Autism Spectrum Disorder: Sensitive Windows of Exposure and Sex Differences

BACKGROUND

Studies have shown that air pollution exposures during pregnancy are associated with an increased risk of autism spectrum disorder (ASD) in children, and the risk appears to be greater for boys. However, studies assessing gestational windows of susceptibility have been mostly limited by trimesters.

OBJECTIVE

We identified sensitive windows of exposure to regional air pollution and risk of ASD and examined sex differences in a large birth cohort.

METHODS

This population-based retrospective cohort study included 294,937 mother-child pairs with singleton deliveries in Kaiser Permanente Southern California (KPSC) hospitals from 2001 to 2014. Children were followed using electronic medical records until clinical ASD diagnosis, non-KPSC membership, death, or 31 December 2019, whichever came first. Weekly mean fine particulate matter [PM with an aerodynamic diameter of ≤2.5μm (PM2.5)], nitrogen dioxide (NO2), and ozone (O3) pregnancy exposures were estimated using spatiotemporal prediction models. Cox proportional hazard models with distributed lags were used to estimate weekly pollutant exposure associations with ASD risk for the entire cohort, and separately for boys and for girls. Models were adjusted for child sex (for full cohort), maternal race/ethnicity, maternal age at delivery, parity, maternal education, maternal comorbidities, medical center, census tract median household income, birth year, and season.

RESULTS

There were 5,694 ASD diagnoses (4,636 boys, 1,058 girls). Sensitive PM2.5 exposure windows associated with ASD were found early in pregnancy, statistically significant throughout the first two trimesters [1-27 wk of gestation, cumulative hazard ratio (HR)=1.14 [95% confidence interval (CI): 1.06, 1.23] per interquartile range (IQR) (7.4-μg/m3) increase]. O3 exposure during 34-37 wk of gestation was associated with increased risk [HR=1.06 (95% CI: 1.01, 1.11) per IQR (17.4 ppb) increase] but with reduced risk during 20-28 wk of gestation [HR=0.93 (95% CI: 0.89, 0.98)]. No associations were observed with NO2. Sex-stratified early gestational PM2.5 associations were stronger among boys [boys HR=1.16 (95% CI: 1.08, 1.26); girls HR=1.06 (95% CI: 0.89, 1.26)]. O3 associations in later gestation were observed only in boys [boys HR=1.10 (95% CI: 1.04, 1.16); girls HR=0.94 (95% CI: 0.84, 1.05)].

CONCLUSIONS

Exposures to PM2.5 in the first two gestational trimesters were associated with increased ASD risk in children, with stronger associations observed for boys. The role of O3 exposure on ASD risk merits further investigation. https://doi.org/10.1289/EHP9509.

Ozone-Based Eye Drops Activity on Ocular Epithelial Cells and Potential Pathogens Infecting the Front of the Eye

Confirmation of the biological effectiveness of new ophthalmic preparations introduced in the market is an important element in maintaining the safety of using this type of medications. This study aimed to investigate the activity of Ozodrop^® on human corneal and conjunctival epithelial cells, as well as its antibacterial and antifungal activity. Cytotoxicity analyses of ocular surface epithelial cells were performed in vitro by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) and Neutral Red uptake assays. The level of nitric oxide released by the cells was assessed by the Griess method. The reduction of the DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical by the tested formulation was analyzed. Microbiological tests were also performed. It was found that the Ozodrop^® preparation exhibited biological activity, but was less active than the reference antibiotics and the anti-yeast agent. The cytotoxic activity of the Ozodrop^® formulation was dependent on the time of cell exposure to it. No toxic effect was observed in the short-term, for up to 3 h. It appeared after 24 h of exposure of the cells to the preparation. The drops showed antioxidant activity in the specified concentration range. They also stimulated the release of nitric oxide, mainly by corneal epithelial cells. The Ozodrop^® formulation exhibits biological activity that can be considered useful in the treatment of infections in the front part of the eye.

The role of brain gaseous neurotransmitters in anxiety

Although anxiety is perhaps one of the most significant current medical and social problems, the neurochemical mechanistic background of this common condition remains to be fully understood. Multifunctional regulatory gasotransmitters are novel, atypical inorganic factors of the brain that are involved in the mechanisms of anxiety responses. Nitric oxide (NO) signaling shows ambiguous action in animal models of anxiety, while NO donors exert anxiogenic or anxiolytic effect depending on their chemical structure, dose, treatment schedule and gas release rapidity. The majority of NO synthase inhibitors act as a relatively potent axiolytic agents, while hydrogen sulfide (H₂S) and carbon monoxide (CO) delivered experimentally in the form of "slow" or "fast" releasing donors have recently been considered as anxiolytic neurotransmitters. In this comprehensive review we critically summarize the literature regarding the intriguing roles of NO, H₂S and CO in the neuromolecular mechanisms of anxiety in the context of their putative, yet promising therapeutic application. A possible mechanism of gasotransmitter action at the level of anxiety-related synaptic transmission is also presented. Brain gasesous neuromediators urgently require further wide ranging studies to clarify their potential value for the current neuropharmacology of anxiety disorders.

The association of short-term effects of air pollution and sleep disorders among elderly residents in China

Sleep disorders, oftentimes co-occurring with other mental and neurological disorders in the elderly, have been previously linked to short-term exposures to air pollution. Here we assessed such associations among 395,651 elderly Chinese in Ningbo, China where air pollution exposures are high and the proportion of elderly in the population is growing. We utilized a regional health information database in China (2008-2017) that collected information on hospital visits for sleep disorders among the elderly (age 60+). Measures of daily air pollution concentrations including nitrogen dioxide (NO₂), sulfur dioxide (SO₂), ozone (O₃), inhalable particles (PM₁₀), and ambient fine particulate matter (PM_2.5) were generated from seven environmental air quality monitoring sites in the study area. We used a generalized additive model to evaluate the associations between hospital visits for sleep disorders and short-term air pollution exposures for up to 7 days prior to a hospital visit. Short-term exposure to multiple air pollutants was associated with hospital visits for sleep disorders in an elderly population; with the strongest associations during 2-3 days prior to a clinic visits for traffic-related pollutants including air quality index (AQI), PM_2.5, PM₁₀, and NO₂ and for SO₂ and O₃ for 5 days prior to the visits. Our study based on large health care record system suggested that short-term air pollution exposures are associated with sleep disorders in the elderly. Considering the individual covariates that could not be adjusted in time-series analyses, future studies with individual level data and an ability to evaluate the severity of sleep disorders and their relation to mental and physical health in general and air pollution are needed. An aging population with increasing health problems and the frequency of high and very high air pollution events in China make our findings very health policy relevant.

Prenatal Ozone Exposure Induces Memory Deficiencies in Newborns Rats

Air pollution is fully acknowledged to represent a major public health issue. Toxic environmental substances, such as ozone, interfere with prenatal development. Animals exposed to ozone (O₃) in utero develop biochemical and morphological alterations. This gas has been proven to decrease cognitive capacity in different species. In the present study, we assessed the possible alterations in memory and spatial learning in the offspring of female rats who were exposed to 1.0 ppm of O₃ embryonic development. Two instruments were used to evaluate possible alterations: the T-maze and a Skinner box. MAPK, ERK, p-ERK, and NR2B proteins, which are widely regarded as responsible for the learning process in the hippocampus and cortex, were also assessed by immunohistochemistry. We found that male rats exposed to O₃in utero displayed a significant delay to reach the correct response using the spatial learning test as compared to the control group. The female rats exposed to O₃ showed a significant delay to reach the correct response as compared to the female control group in the Skinner box. We also found that while the male rats showed decrease in significant differences in the expression of NR2B, ERK and increase in MAPK. Females only showed increase in MAPK, p-ERK and decrease in ERK, when compared to their respective control group. It is possible that the deficits are associated to hormonal expression, inflammation and oxidative stress alterations. In summary, these results suggest that exposure to O₃ can interfere with prenatal development, resulting in learning and memory deficiencies in rats.

Curcumin Exerted Neuroprotection against Ozone-Induced Oxidative Damage and Decreased NF-κB Activation in Rat Hippocampus and Serum Levels of Inflammatory Cytokines

Ozone is a harmful tropospheric pollutant, causing the formation of reactive oxygen and nitrogen species that lead to oxidative damage in living beings. NF-κB can be activated in response to oxidative damage, inducing an inflammatory response. Nowadays, there are no reliable results that consolidate the use of antioxidants to protect from damage caused by ozone, particularly in highly polluted cities. Curcumin has a strong antioxidant activity and is a potent inhibitor of NF-κB activation with no side effects. The aim of this study is to evaluate the effect of curcumin in preventive and therapeutic approaches against oxidative damage, NF-κB activation, and the rise in serum levels of IL-1β and TNF-α induced by acute and chronic exposure to ozone in rat hippocampus. One hundred male Wistar rats were distributed into five groups; the intact control, curcumin-fed control, the ozone-exposed group, and the preventive and therapeutic groups. These last two groups were exposed to ozone and received food supplemented with curcumin. Lipid peroxidation was determined by spectrophotometry, and protein oxidation was evaluated by immunodetection of carbonylated proteins and densitometry analysis. Activation of NF-κB was assessed by electrophoretic mobility shift assay (EMSA), and inflammatory cytokines (IL-1β and TNF-α) were determined by ELISA. Curcumin decreased NF-κB activation and serum levels of inflammatory cytokines as well as protein and lipid oxidation, in both therapeutic and preventive approaches. Curcumin has proven to be a phytodrug against the damage caused by the environmental exposure to ozone.