[Toxic Components of PM2.5 and Their Toxicity Mechanisms-On the Toxicity of Sulfate and Carbon Components]

Source-specific fine particulates emission linked to prevalence of ophthalmic cases in India

Particulate Matter (PM) pollution is a prime component of air pollution and poses a substantial risk to human health, including the eye. This work envisioned to show the impact of PM2·5 pollution on the Ophthalmic disease prevalence in India. This national-level observational-based cross-sectional retrospective study included the hospital-reported ophthalmic outpatients in 2019-20. The sector-wise high-resolution (0·1° × 0·1°) PM2·5 emission data along with the annual average PM2·5 concentration data for 2019 from NASA is adopted for the risk factor analysis. Nearly 32·6 million footfalls are recorded in various hospitals due to ophthalmic morbidity in 2019, out of which surprisingly ~ 80% of cases are registered in rural India. Half of the total ophthalmic disease burden comes from the top 100 districts out of the total 720 districts in India. The inferential analyses depicted a statistically significant positive correlation (r = 0·54, 95% CI 0·48 - 0·59, P < 0·001) between the PM2·5 emission and ophthalmic outpatients. The risk of eye disease in the exposed rural population is 4 times higher than the unexposed population 4·19 (4·19 - 4·2). The PM2·5 emission from household cooking activity shows a greater correlation (r2 = 0·28, 95% CI 0·22 - 0·35, P < 0·001) with the occurrence of ophthalmic cases in India followed by incense stick and mosquito coil burning (r2 = 0·28 (0·22 - 0·34)), and transportation (r2 = 0·24 (0·18 - 0·29)). The meteorological parameters like temperature and humidity show very little association and precipitation shows a negative correlation with the number of ophthalmic outpatients in India. This study suggests that surface emission data could be a potential tool to link prevailing diseases in India.

Effects of particulate air pollution exposure on lung-brain axis and related miRNAs modulation in mouse models

Particulate matter exposure is linked to numerous health issues, including respiratory, cardiovascular, and neurodegenerative diseases. This review focuses on the biological mechanisms through which air pollution influences the lung-brain axis, highlighting the role of miRNAs in regulating gene pathways affected by PM. Some microRNAs (miRNAs) are identified as key modulators of cellular processes, including inflammation, epithelial-to-mesenchymal transition (EMT), and blood-brain barrier integrity. Using mice models to study these effects allows for controlled experimentation on the systemic distribution of PM across biological barriers. Among the imaging technologies, Positron Emission Tomography is the best approach to monitor the distribution and effects of PM in vivo. The research underscores the importance of miRNA profiles as potential markers for the health effects of PM exposure, suggesting that specific miRNAs could serve as early indicators of damage to the lung-brain axis.

Long-Term Exposure to PM2.5 Constituents, Genetic Susceptibility, and Incident Dementia: A Prospective Cohort Study among 0.2 Million Older Adults

Fine particulate matter, known as PM2.5, is recognized as a risk factor for dementia. However, the specific linkage between PM2.5 constituents and dementia is not well understood. We conducted a cohort of 217,336 participants of the UK Biobank to explore the association of long-term exposure to PM2.5 constituents with all-cause dementia, Alzheimer's disease (AD), and vascular dementia. We estimated PM2.5 constituents based on residential addresses by an evaluation model and used time-varying Cox models and Quantile g-computation models to assess the effects of individual constituents and their mixtures. Genetic susceptibility to dementia was assessed using a polygenic risk score, and its multiplicative and additive interactions with PM2.5 constituents were analyzed. Our results showed that black carbon (BC), ammonium (NH4+), organic matter (OM), and sulfate (SO42-) were positively associated with all-cause dementia, while BC and OM were linked to AD, with BC being the most influential. The combined effect of PM2.5 constituents and genetic risk was stronger than their individual effect. This study offers new insights into the association between PM2.5 constituents and dementia, especially those from fuel combustion and automobile exhaust, and highlights the need for effective prevention strategies.

Association between exposure to environmental pollutants and increased oral health risks, a comprehensive review

The burden of disease and death attributable to environmental pollution is a growing public health challenge worldwide, particularly in developing countries. While the adverse effects of environmental pollution on oral health have garnered increasing attention, a comprehensive and systematic assessment remains lacking. This article delves into the intricate relationship between environmental pollution and oral health, highlighting significant impacts on various aspects such as dental caries, periodontal diseases, oral facial clefts, cancer, as well as other oral diseases. Our results suggested that secondhand smoke, particulate matters (PM) and heavy metals are the most important risk factors affecting oral health. Additional contributors, such as radiation pollutants, electronic cigarette, phthalates, gaseous air pollutants, pesticides, solvents, wood dust, formaldehyde and excessive fluoride were investigated, though evidence for their impacts remains limited and often inconclusive. The review also explores potential mechanisms underlying these impacts, including microorganism, inflammation, oxidative stress, genetic influences, and toxicant exposures from heavy metals and other pollutants. For instance, PM2.5 may contribute to dental caries by disrupting oral pH balance and absorbing heavy metals such as lead and cadmium which have been considered as caries promoting elements. It is also associated with adverse inflammatory responses and tissue damage in periodontal tissues by causing oxidative stress, potentially leading to periodontitis. Drawing on current evidence, it provides a comprehensive analysis of these associations, offering critical insights to guide the development of preventive strategies and public health interventions. The findings highlight the pressing need for future research to validate the causal links between environmental pollution and oral diseases and to unravel the underlying biological mechanisms. Ultimately, greater attention must be directed toward addressing the relationship between environmental pollution and oral diseases, with a focus on pollution control and the reduction of preventable environmental risks to safeguard oral health on a broader scale.

Short- and medium-term exposure to ambient air pollution and periodontal status

We investigated the association between ambient air pollutant exposure and periodontal health using data from 17,271 adults in the Korea National Health and Nutrition Examination Survey (2012-2015). Participants' periodontal status was categorized based on their community periodontal index (CPI) scores. Using multiple logistic regression models, we examined the relationship between air pollutant levels and poor periodontal status at various lag periods. After adjusting for potential confounders, PM10 exposure was associated with a poor periodontal status (short-term: 0-1 and 0-2 lag days; medium-term: 0-1 and 0-2 lag months). SO2 exposure showed similar associations (short-term, 0-2 to 0-7 lag days; medium-term, 0-4 to 0-6 lag months). Only increased medium-term O3 exposure (0-2 to 0-6 lag months) was associated with a poor periodontal status. NO2 exposure was inversely associated with poor periodontal status for both short- and medium-term durations.

Neurodevelopmental toxicity induced by PM2.5 Exposure and its possible role in Neurodegenerative and mental disorders

Recent extensive evidence suggests that ambient fine particulate matter (PM2.5, with an aerodynamic diameter ≤2.5 μm) may be neurotoxic to the brain and cause central nervous system damage, contributing to neurodevelopmental disorders, such as autism spectrum disorders, neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease, and mental disorders, such as schizophrenia, depression, and bipolar disorder. PM2.5 can enter the brain via various pathways, including the blood-brain barrier, olfactory system, and gut-brain axis, leading to adverse effects on the CNS. Studies in humans and animals have revealed that PM2.5-mediated mechanisms, including neuroinflammation, oxidative stress, systemic inflammation, and gut flora dysbiosis, play a crucial role in CNS damage. Additionally, PM2.5 exposure can induce epigenetic alterations, such as hypomethylation of DNA, which may contribute to the pathogenesis of some CNS damage. Through literature analysis, we suggest that promising therapeutic targets for alleviating PM2.5-induced neurological damage include inhibiting microglia overactivation, regulating gut microbiota with antibiotics, and targeting signaling pathways, such as PKA/CREB/BDNF and WNT/β-catenin. Additionally, several studies have observed an association between PM2.5 exposure and epigenetic changes in neuropsychiatric disorders. This review summarizes and discusses the association between PM2.5 exposure and CNS damage, including the possible mechanisms by which PM2.5 causes neurotoxicity.

Exposure to fine particulate matter constituents and cognitive function performance, potential mediation by sleep quality: A multicenter study among Chinese adults aged 40-89 years

Although exposure to fine particulate matter (PM_2.5) has been associated with cognitive decline, little is known about which PM_2.5 constituents are more harmful. Recent study on the association between PM_2.5 and sleep quality prompted us to propose that sleep quality may mediate the adverse effects of PM_2.5 components on cognitive decline. Understanding the association between PM_2.5 constituents and cognitive function, as well as the mediating role of sleep quality provides a future intervention target for improving cognitive function. Using data involving 1834 participants from a multicenter cross-sectional study in nine cities of the Beijing-Tianjin-Hebei (BTH) region in China, we undertook multivariable linear regression analyses to quantify the association of annual moving-average PM_2.5 and its chemical constituents with cognitive function and to assess the modifying role of exposure characteristic in this association. Besides, we examined the extent to which this association of PM_2.5 constituents with cognitive function was mediated via sleep quality by a mediation analysis. We observed significantly negative associations between an increase of one interquartile range increase in PM_2.5 [-0.876 (95 % CI: -1.205, -0.548)], organic carbon [-0.481 (95 % CI: -0.744, -0.219)], potassium [-0.344 (95 % CI: -0.530, -0.157)], iron [-0.468 (95 % CI: -0.646, -0.291)], and ammonium ion [-0.125 (95 % CI: -0.197, -0.052)] and cognitive decline. However, we didn't find any individual components more harmful than PM_2.5. Poor sleep quality partially mediated the estimated associations, which were explained ranging from 2.28 % to 11.99 %. Stratification analyses showed that people living in areas with lower greenspace were more susceptible to specific PM_2.5 components. Our study suggests that the adverse effect of suffering from PM_2.5 components is more pronounced among individuals with poor sleep quality, amplifying environmental inequalities in health. Besides reducing environmental pollution, improving sleep quality may be another measure worth considering to improve cognition if our research is confirmed in the future.

Epigenetic Regulation in Exposome-Induced Tumorigenesis: Emerging Roles of ncRNAs

Environmental factors, including pollutants and lifestyle, constitute a significant role in severe, chronic pathologies with an essential societal, economic burden. The measurement of all environmental exposures and assessing their correlation with effects on individual health is defined as the exposome, which interacts with our unique characteristics such as genetics, physiology, and epigenetics. Epigenetics investigates modifications in the expression of genes that do not depend on the underlying DNA sequence. Some studies have confirmed that environmental factors may promote disease in individuals or subsequent progeny through epigenetic alterations. Variations in the epigenetic machinery cause a spectrum of different disorders since these mechanisms are more sensitive to the environment than the genome, due to the inherent reversible nature of the epigenetic landscape. Several epigenetic mechanisms, including modifications in DNA (e.g., methylation), histones, and noncoding RNAs can change genome expression under the exogenous influence. Notably, the role of long noncoding RNAs in epigenetic processes has not been well explored in the context of exposome-induced tumorigenesis. In the present review, our scope is to provide relevant evidence indicating that epigenetic alterations mediate those detrimental effects caused by exposure to environmental toxicants, focusing mainly on a multi-step regulation by diverse noncoding RNAs subtypes.

Trimester-Specific Association of Maternal Exposure to Fine Particulate Matter and its Components With Birth and Placental Weight in Japan

OBJECTIVE

We investigated which trimester of exposure to PM2.5 and its components was associated with birth and placental weight, and the fetoplacental weight ratio.

METHODS

The study included 63,990 women who delivered singleton term births within 23 Tokyo wards between 2013 and 2015. Each day, we collected fine particles on a filter, and analyzed their chemical constituents, including carbons and ions. Trimester-specific exposure to each pollutant was estimated based on the average daily concentrations.

RESULTS

Over the third trimester, sulfate exposure tended to be inversely associated with birth weight, and decreased placental weight (difference for highest vs lowest quintile groups = -6.7 g, 95% confidence interval = -12.5 to -0.9). For fetoplacental weight ratio, there was no relationship.

CONCLUSIONS

Sulfate exposure over the third trimester may reduce birth weight, particularly placental weight.

Effects of PM2.5 exposure on reproductive system and its mechanisms

With the development of human society, haze has become an important form of air pollution. Haze is a mixture of fog and haze, and the main component of haze is fine particulate matter (PM_2.5), which is the most important indicator of composite air pollution. Epidemiological studies proved that PM_2.5 can break through the respiratory mucosal barrier and enter the human body, causing pathological effects on multiple systems of the body. In the past, people put more attention to PM_2.5 in the respiratory system, cardiovascular system, nervous system, etc, and relatively paid less attention to the reproductive system. Recent studies have shown that PM_2.5 will accumulate in the reproductive organs through blood-testis barrier, placental barrier, epithelial barrier and other barriers protecting reproductive tissues. In addition, PM_2.5 can disrupt hormone levels, ultimately affecting fertility. Prior studies have shown that oxidative stress, inflammation, apoptosis, and the breakdown of barrier structures are now considered to contribute to reproductive toxicity and may cause damage at the molecular and genetic levels. However, the exact mechanism remains to be elucidated. Our review aims to provide an understanding of the pathological effects of PM_2.5 on reproductive system and the existing injury mechanism.

Potential effects of noxious chemical-containing fine particulate matter on oral health through reactive oxygen species-mediated oxidative stress: Promising clues

Nowadays, air pollution which is dominated by fine particulate matter with aerodynamic diameter less than or equal to 2.5 µm resulting from rapid industrialization and urbanization combined with population explosion has become more and more severe problem to mankind and the whole planet because of its diversity of deleterious effects. The latest data estimated that exposure to fine particulate matter, or PM2.5, contributes to approximately 4 million deaths worldwide due to cardiopulmonary conditions such as heart disease and stroke, respiratory infections, chronic lung disease and lung cancer. During recent years, there has been growing concern about the adverse effects of this global threat on oral health which is one of key components of general health and quality of life. Although a few studies have reported such possible association, the findings are still far from conclusion. Moreover, the underlying mechanisms remain unclear. To our knowledge, the analysis of literature regarding this scope has yet been published. Thus, current work systematically assesses existing evidences on the potential association between exposure to PM2.5 and the development of various oral diseases as well as figures out the plausible paradigm of PM2.5-induced damages in the oral cavity through its toxic chemical constituents along with its ability to induce oxidative stress via reactive oxygen species production. This might partially provide the clues for new research ideas and progression in the field of oral health.

Potential Protective and Therapeutic Roles of the Nrf2 Pathway in Ocular Diseases: An Update

Nuclear factor- (erythroid-derived 2-) like 2 (Nrf2) is a regulator of many processes of life, and it plays an important role in antioxidant, anti-inflammatory, and antifibrotic responses and in cancer. This review is focused on the potential mechanism of Nrf2 in the occurrence and development of ocular diseases. Also, several Nrf2 inducers, including noncoding RNAs and exogenous compounds, which control the expression of Nrf2 through different pathways, are discussed in ocular disease models and ocular cells, protecting them from dysfunctional changes. Therefore, Nrf2 might be a potential target of protecting ocular cells from various stresses and preventing ocular diseases.