Causal relationships between genetically predicted particulate air pollutants and neurodegenerative diseases: A two-sample Mendelian randomization study

Accumulating observational studies have linked particulate air pollutants to neurodegenerative diseases (NDDs). However, the causal links and the direction of their associations remain unclear. Therefore, we adopted a two-sample Mendelian randomization (TSMR) design using the GWAS-based genetic instruments of particulate air pollutants (PM2.5 and PM10) from the UK Biobank to explore their causal influence on four common neurodegenerative diseases. Estimates of causative relationships were generated by the Inverse variance weighted (IVW) method with multiple sensitive analyses. The heterogeneity and pleiotropy tests were additionally performed to verify whether our findings were robust. Genetically predicted PM2.5 and PM10 could elevate the occurrence of AD (odds ratio [OR] = 2.22, 95 % confidence interval [CI] 1.53-3.22, PIVW = 2.85×10-5, PFalsediscovery rate[FDR]= 2.85×10-4 and OR = 2.41, 95 % CI: 1.26-4.60, PIVW = 0.008, PFDR=0.039, respectively). The results were robust in sensitive analysis. However, no evidence of causality was found for other NDDs. Our present study suggests that PM2.5 and PM10 have a detrimental effect on AD, which indicates that improving air quality to prevent AD may have pivotal public health implications.

Telehealth Feasibility, Interest, and Satisfaction of Patients with Multiple Sclerosis Living in the Veneto Region, Italy, During the COVID-19 Pandemic

Introduction: Synchronous telehealth (ST) consists of the remote real-time delivery of health services. COVID-19 pandemic has pressed the use of ST and forced neurologists to deliver telehealth services. The aim of this study was to obtain the actual picture of ST accessibility/interest and to evaluate the user satisfaction in patients with multiple sclerosis (MS) during the COVID-19 pandemic. Methods: The study consisted of two phases. First, a hard-copy questionnaire ("Telehealth Identity Card" [TIC]), including only yes/no questions, filled in the presence of a neurologist, and investigating the technical/practical access and the willingness/interest of MS patients to the telehealth services, was obtained from 600 consecutive outpatients, with no time limit for answering. Second, a fully filled "Televisit Satisfaction Questionnaire" (TSQ) was obtained from 100 consecutive patients that underwent a televisit. Statistical analysis applied the t test for normally distributed variables and the Mann-Whitney U test for ordinal. Logistic univariate and multivariate regressions were applied to predict televisit availability on the base of demographic variables. Results: Statistical analysis was performed on 552/600 consecutive TIC (92%). Of them, 464/552 (84%) of the MS patients declared to possess the tools and to be interested in telehealth services. Compared with noninterested patients, they were younger (mean age: 44.0 vs. 49.8, p < 0.001) and with lower disability (mean Expanded Disability Status Scale: 2.5 vs. 3.3, p < 0.01). From TSQ, it emerged that 95% agree or strongly agree that televisit respected timelines, saved time and money, was conducted with respect to privacy, can be a useful tool for monitoring disease and therapy, and expressed their availability for further televisits. Discussion: A great majority of MS patients living in Padua Province were interested in telehealth. High satisfaction and the willingness for further televist were expressed. Telehealth services can help neurologists to manage the increasing number of MS patients and their complex therapeutic monitoring.

The lung-brain axis in multiple sclerosis: Mechanistic insights and future directions

Multiple sclerosis is a chronic inflammatory demyelinating disease of the central nervous system with progressive lifelong disability. Current treatments are particularly effective at the early inflammatory stage of the disease but associate with safety concerns such as increased risk of infection. While clinical and epidemiological evidence strongly support the role of a bidirectional communication between the lung and the brain in MS in influencing disease risk and severity, the exact processes underlying such relationship appear complex and not fully understood. This short review aims to summarize key findings and future perspectives that might provide new insights into the mechanisms underpinning the lung-brain axis in MS.

Particulate matter exposure and neurodegenerative diseases: A comprehensive update on toxicity and mechanisms

Exposure to particulate matter (PM) has been associated with a range of health impacts, including neurological abnormalities that affect neurodevelopment, neuroplasticity, and behavior. Recently, there has been growing interest in investigating the possible relationship between PM exposure and the onset and progression of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and multiple sclerosis. However, the precise mechanism by which PM affects neurodegeneration is still unclear, even though several epidemiological and animal model studies have provided mechanistic insights. This article presents a review of the current research on the neurotoxicity of PM and its impact on neurodegenerative diseases. This review summarizes findings from epidemiological and animal model studies collected through searches in Google Scholar, PubMed, Web of Science, and Scopus. This review paper also discusses the reported effects of PM exposure on the central nervous system and highlights research gaps and future directions. The information presented in this review may inform public health policies aimed at reducing PM exposure and may contribute to the development of new treatments for neurodegenerative diseases. Further mechanistic and therapeutic research will be needed to fully understand the relationship between PM exposure and neurodegenerative diseases.

Air Pollution and Its Adverse Effects on the Central Nervous System

Air pollution is recognized as a significant public health problem and is associated with illnesses of the central nervous system (CNS) as well as neuroinflammation and neuropathology. Air pollution may cause chronic brain inflammation, white matter abnormalities, and microglia activation, which increases the risk of autism spectrum disorders, neurodegenerative disorders, stroke, and multiple sclerosis (MS). Methods: A literature review was done on "PubMed, EMBASE and Web of Science" on the relationship of air pollution with MS and stroke, using the keywords "air pollution" OR "pollution"; "ambient air pollution," "particulate matter, ozone, black carbon" AND "stroke" OR "cerebrovascular diseases," "multiple sclerosis," "neuroinflammation," or "neurodegeneration." Results: We first identified 128 articles and their related websites, of which 44 articles were further selected for analysis mainly based on study relevance, study quality and reliability, and date of publication. Further studies on air pollution and its adverse effects on the CNS are needed. The findings of such studies will support the development of appropriate preventive measures in the future.

Air Pollution-Related Neurotoxicity Across the Life Span

Air pollution is a complex mixture of gases and particulate matter, with adsorbed organic and inorganic contaminants, to which exposure is lifelong. Epidemiological studies increasingly associate air pollution with multiple neurodevelopmental disorders and neurodegenerative diseases, findings supported by experimental animal models. This breadth of neurotoxicity across these central nervous system diseases and disorders likely reflects shared vulnerability of their inflammatory and oxidative stress-based mechanisms and a corresponding ability to produce brain metal dyshomeo-stasis. Future research to define the responsible contaminants of air pollution underlying this neurotoxicity is critical to understanding mechanisms of these diseases and disorders and protecting public health.

The pathophysiological and molecular mechanisms of atmospheric PM2.5 affecting cardiovascular health: A review

BACKGROUND

Exposure to ambient fine particulate matter (PM2.5, with aerodynamic diameter less than 2.5 µm) is a leading environmental risk factor for global cardiovascular health concern.

OBJECTIVE

To provide a roadmap for those new to this field, we reviewed the new insights into the pathophysiological and cellular/molecular mechanisms of PM2.5 responsible for cardiovascular health.

MAIN FINDINGS

PM2.5 is able to disrupt multiple physiological barriers integrity and translocate into the systemic circulation and get access to a range of secondary target organs. An ever-growing body of epidemiological and controlled exposure studies has evidenced a causal relationship between PM2.5 exposure and cardiovascular morbidity and mortality. A variety of cellular and molecular biology mechanisms responsible for the detrimental cardiovascular outcomes attributable to PM2.5 exposure have been described, including metabolic activation, oxidative stress, genotoxicity, inflammation, dysregulation of Ca2+ signaling, disturbance of autophagy, and induction of apoptosis, by which PM2.5 exposure impacts the functions and fates of multiple target cells in cardiovascular system or related organs and further alters a series of pathophysiological processes, such as cardiac autonomic nervous system imbalance, increasing blood pressure, metabolic disorder, accelerated atherosclerosis and plaque vulnerability, platelet aggregation and thrombosis, and disruption in cardiac structure and function, ultimately leading to cardiovascular events and death. Therein, oxidative stress and inflammation were suggested to play pivotal roles in those pathophysiological processes.

CONCLUSION

Those biology mechanisms have deepen insights into the etiology, course, prevention and treatment of this public health concern, although the underlying mechanisms have not yet been entirely clarified.

The impact of PM2.5, PM10 and NO2 on Covid-19 severity in a sample of patients with multiple sclerosis: A case-control study

BACKGROUND

Many studies investigated the association between air pollution and Covid-19 severity but the only study focusing on patients with Multiple Sclerosis (MS) exclusively evaluated exposure to PM2.5. We aim to study, in a sample of MS patients, the impact of long-term exposure to PM2.5, PM10 and NO2 on Covid-19 severity, described as occurrence of pneumonia.

METHODS

A 1:2 ratio case-control study was designed, differentiating cases and controls based on Covid-19 pneumonia. Associations between pollutants and outcome were studied using logistic regression. Weighted quantile sum (WQS) logistic regression was used to identify the individual contribution of each pollutant within the mixture; Least Absolute Shrinkage and Selection Operator (LASSO) penalized regression was performed to confirm the variable selection from WQS. All the analyses were adjusted for confounders selected a priori.

RESULTS

Of the 615 eligible patients, 491 patients provided detailed place of exposure and were included in the principal analysis. Higher concentrations of air pollutants were associated with increased odds of developing Covid-19 pneumonia (PM2.5: 3rd vs 1st tercile OR(95% CI)=2.26(1.29;3.96); PM10: 3rd vs 1st tercile OR(95% CI)=2.12(1.22;3.68); NO2: 3rd vs 1st tercile OR(95% CI)=2.12(1.21;3.69)). Pollutants were highly correlated with each other; WQS index was associated to an increased risk of pneumonia (β=0.44; p-value=0.004) and the main contributors to this association were NO2 (41%) and PM2.5 (34%). Consistently, Lasso method selected PM2.5 and NO2.

CONCLUSIONS

Higher long-term exposure to PM2.5, PM10 and NO2 increased the odds of Covid-19 pneumonia among MS patients and the most dangerous pollutants were NO2 and PM2.5.

Different components of air pollutants and neurological disorders

The harmful effects of air pollution can cause various diseases. Most research on the hazards of air pollution focuses on lung and cardiovascular diseases. In contrast, the impact of air pollution on neurological disorders is not widely recognized. Air pollution can cause various neurological conditions and diseases, such as neural inflammation, neurodegeneration, and cerebrovascular barrier disorder; however, the mechanisms underlying the neurological diseases induced by various components of air pollutants remain unclear. The present paper summarizes the effects of different components of air pollutants, including particulate matter, ozone, sulfur oxides, carbon oxides, nitrogen oxides, and heavy metals, on the nervous system and describes the impact of various air pollutants on neurological disorders, providing ideas for follow-up research.

Toxic Air Pollutants and Their Effect on Multiple Sclerosis: A Review Study

Toxic air pollutants are one of the main factors that have the effect of synergism to increase the incidence of multiple sclerosis (MS). This review aims to investigate the effects of toxic air pollutants on the occurrence of multiple sclerosis (MS). A narrative review of the literature was done from 2000 to 2022 based on various databases such as Google Scholar, Web of Science, Springer, PubMed, and Science Direct. In this study, according to the databases, three hundred and sixty articles were retrieved. Of these, 28 studies were screened after review and 14 full-text articles entered into the analysis process. Finally, 9 articles were selected in this study. According to the finding of this study, toxic air pollutants including polycyclic aromatic hydrocarbons (PAHs), heavy metals (HM), volatile organic compounds (VOCs), particulate matter (PM), and gases are the main agents that cause the development and spread of chronic diseases such as respiratory and cardiovascular diseases, chronic obstructive pulmonary disease (COPD), and multiple sclerosis. The result of this study showed that the main sources of emission of toxic air pollutants include industries, cars, power plants, and the excessive consumption of fossil fuels. In general, the inhalation of high concentration of toxic air pollutants can increase the risk of chronic diseases and multiple sclerosis.

Ultrafine Diesel Exhaust Particles Induce Apoptosis of Oligodendrocytes by Increasing Intracellular Reactive Oxygen Species through NADPH Oxidase Activation

Diesel exhaust particles (DEPs) are a main contributor to air pollution. Ultrafine DEPs can cause neurodegenerative diseases by increasing intracellular reactive oxygen species (ROS). Compared with other cells in the brain, oligodendrocytes responsible for myelination are more susceptible to oxidative stress. However, the mechanisms underlying ROS generation in oligodendrocytes and the susceptibility of oligodendrocytes to ROS by ultrafine DEPs remain unclear. Herein, we examined the effects of excessive ROS generated by NOX2, an isoform of the NADPH oxidase family, after exposure to ultrafine DEPs (200 μg/mL) on the survival of two types of oligodendrocytes—oligodendrocyte precursor cells (OPCs) and mature oligodendrocytes (mOLs)––isolated from the brain of neonatal rats. In addition, mice were exposed to ultrafine DEP suspension (20 μL, 0.4 mg/mL) via the nasal route for 1 week, after which the expression of NOX2 and cleaved caspase-3 was examined in the white matter of the cerebellum. Exposure to DEPs significantly increased NOX2 expression and ROS generation in OPCs and mOLs. OPCs and mOLs clearly exhibited viability reduction, and a significant change in p53, Bax, Bcl-2, and cleaved caspase-3 expression, after DEP exposure. In contrast, treatment with berberine (BBR), an NOX2 inhibitor, significantly mitigated these effects. In mice exposed to DEP, the presence of NOX2-positive and cleaved caspase-3-positive oligodendrocytes was demonstrated in the cerebellar white matter; NOX2 and cleaved caspase-3 expression in the cerebellum lysates was significantly increased. BBR treatment returned expression of these proteins to control levels. These results demonstrate that the susceptibility of OPCs and mOLs to ultrafine DEPs is, at least in part, caused by excessive ROS produced by NOX2 and the sequential changes in the expression of p53, Bax, Bcl-2, and cleaved caspase-3. Overall, NOX2 inhibitor enhances the survival of two types of oligodendrocytes.

Atmospheric particulate matter aggravates CNS demyelination through involvement of TLR-4/NF-kB signaling and microglial activation

Atmospheric Particulate Matter (PM) is one of the leading environmental risk factors for the global burden of disease. Increasing epidemiological studies demonstrated that PM plays a significant role in CNS demyelinating disorders; however, there is no direct testimony of this, and yet the molecular mechanism by which the occurrence remains unclear. Using multiple in vivo and in vitro strategies, in the present study we demonstrate that PM exposure aggravates neuroinflammation, myelin injury, and dysfunction of movement coordination ability via boosting microglial pro-inflammatory activities, in both the pathological demyelination and physiological myelinogenesis animal models. Indeed, pharmacological disturbance combined with RNA-seq and ChIP-seq suggests that TLR-4/NF-kB signaling mediated a core network of genes that control PM-triggered microglia pathogenicity. In summary, our study defines a novel atmospheric environmental mechanism that mediates PM-aggravated microglia pathogenic activities, and establishes a systematic approach for the investigation of the effects of environmental exposure in neurologic disorders.

The effects of air pollution, meteorological parameters, and climate change on COVID-19 comorbidity and health disparities: A systematic review

Air pollutants, especially particulate matter, and other meteorological factors serve as important carriers of infectious microbes and play a critical role in the spread of disease. However, there remains uncertainty about the relationship among particulate matter, other air pollutants, meteorological conditions and climate change and the spread of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), hereafter referred to as COVID-19. A systematic review was conducted using PRISMA guidelines to identify the relationship between air quality, meteorological conditions and climate change, and COVID-19 risk and outcomes, host related factors, co-morbidities and disparities. Out of a total of 170,296 scientific publications screened, 63 studies were identified that focused on the relationship between air pollutants and COVID-19. Additionally, the contribution of host related-factors, co-morbidities, and health disparities was discussed. This review found a preponderance of evidence of a positive relationship between PM_2.5, other air pollutants, and meteorological conditions and climate change on COVID-19 risk and outcomes. The effects of PM_2.5, air pollutants, and meteorological conditions on COVID-19 mortalities were most commonly experienced by socially disadvantaged and vulnerable populations. Results however, were not entirely consistent, and varied by geographic region and study. Opportunities for using data to guide local response to COVID-19 are identified.

Ambient air pollution and multiple sclerosis: a systematic review

OBJECTIVES

Some studies have shown that environmental risk factors, including air pollution, might be related to the incidence or recurrence of multiple sclerosis (MS). This systematic review was conducted to investigate the relation between air pollution and MS.

METHODS

A systematic search was conducted in PubMed, Scopus, Science Direct, Embase, and Web of Science; until January 2020 with no restrictions. The search strategy was conducted with air pollution key words such as CO, PM_2.5, PM₁₀, SO₂, and NO₂, for exposure and the key word "Multiple sclerosis" as the outcome.

RESULTS

Eventually, after applying the inclusion and exclusion criteria, 17 articles were included. The methodologies and outcomes reported were heterogeneous and different metrics had been used in the results; therefore conducting a meta-analysis was not possible. Eight studies had analyzed the relation between particulate matter (PM) and the prevalence or relapse of MS and had observed a significant relation. NO₂ and NOx were associated with recurrence or prevalence of MS in three studies. But, in three cohort studies, no association was observed between air pollution and recurrence or occurrence of MS.

CONCLUSIONS

The results of this systematic review show that outdoor air pollution, especially PM and nitrogen oxides might be related to the prevalence or relapse of MS.

The effect of air pollution on COVID-19 severity in a sample of patients with multiple sclerosis

Background and purpose

Some studies have shown that air pollution, often assessed by thin particulate matter with diameter below 2.5 µg/m³ (PM2.5), may contribute to severe COVID‐19 courses, as well as play a role in the onset and evolution of multiple sclerosis (MS). However, the impact of air pollution on COVID‐19 has never been explored specifically amongst patients with MS (PwMS). This retrospective observational study aims to explore associations between PM2.5 and COVID‐19 severity amongst PwMS.

Methods

Data were retrieved from an Italian web‐based platform (MuSC‐19) which includes PwMS with COVID‐19. PM2.5 2016–2018 average concentrations were provided by the Copernicus Atmospheric Monitoring Service. Italian patients inserted in the platform from 15 January 2020 to 9 April 2021 with a COVID‐19 positive test were included. Ordered logistic regression models were used to study associations between PM2.5 and COVID‐19 severity.

Results

In all, 1087 patients, of whom 13% required hospitalization and 2% were admitted to an intensive care unit or died, were included. Based on the multivariate analysis, higher concentrations of PM2.5 increased the risk of worse COVID‐19 course (odds ratio 1.90; p = 0.009).

Conclusions

Even if several other factors explain the unfavourable course of COVID‐19 in PwMS, the role of air pollutants must be considered and further investigated.

Genetic, Environmental and Lifestyle Determinants of Accelerated Telomere Attrition as Contributors to Risk and Severity of Multiple Sclerosis

Telomeres are protective structures at the ends of linear chromosomes. Shortened telomere lengths (TL) are an indicator of premature biological aging and have been associated with a wide spectrum of disorders, including multiple sclerosis (MS). MS is a chronic inflammatory, demyelinating and neurodegenerative disease of the central nervous system. The exact cause of MS is still unclear. Here, we provide an overview of genetic, environmental and lifestyle factors that have been described to influence TL and to contribute to susceptibility to MS and possibly disease severity. We show that several early-life factors are linked to both reduced TL and higher risk of MS, e.g., adolescent obesity, lack of physical activity, smoking and vitamin D deficiency. This suggests that the mechanisms underlying the disease are connected to cellular aging and senescence promoted by increased inflammation and oxidative stress. Additional prospective research is needed to clearly define the extent to which lifestyle changes can slow down disease progression and prevent accelerated telomere loss in individual patients. It is also important to further elucidate the interactions between shared determinants of TL and MS. In future, cell type-specific studies and advanced TL measurement methods could help to better understand how telomeres may be causally involved in disease processes and to uncover novel opportunities for improved biomarkers and therapeutic interventions in MS.

Multiple sclerosis epidemiological trends in Italy highlight the environmental risk factors

Italy is definitely a high-risk country for multiple sclerosis (MS). Over the last 50 years, several epidemiological studies, including longitudinal surveys, have disclosed that MS incidence and prevalence in Italy mainland and Islands (Sardinia and Sicily) have progressively increased, picturing a semi-parabolic curve. Based on the comprehensive scrutiny of 58 papers, we conclude that the latitude risk gradient does not fit to the Italian map of MS. The genetic heterogeneity of the Italian ethnicities, that likely forms the basis of MS predisposition, does not account for the dramatic increase of MS incidence and prevalence observed in Italy over the last half century that, rather, seems better explained by the effect of environmental factors.

Role of environmental factors in multiple sclerosis

INTRODUCTION

Environmental factors play a significant role in the pathogenesis and progression of multiple sclerosis (MS), either acting alone or by interacting with other environmental or genetic factors. This cumulative exposure to external risk factors is highly complex and highly variable between individuals.

AREAS COVERED

We narratively review the current evidence on the role of environment-specific risk factors in MS onset and progression, as well as the effect of gene-environment interactions and the timing of exposure We have reviewed the latest literature, by Ovid Medline, retrieving the most recently published systematic reviews and/or meta-analyses and more recent studies not previously included in meta-analyses or systematic reviews.

EXPERT OPINION

There is some good evidence supporting the impact of some environmental risk factors in increasing the risk of developing MS. Tobacco smoking, low vitamin D levels and/or low sun exposure, Epstein Barr Virus (EBV) seropositivity and a history of infectious mononucleosis may increase the risk of developing MS. Additionally, there is some evidence that gene-smoking, gene-EBV, and smoking-EBV interactions additively affect the risk of MS onset. However, the evidence for a role of other environmental factors in MS progression is limited. Finally, there is some evidence that tobacco smoking, insufficient vitamin D levels and/or sun exposure have impacts on MS phenotypes and various markers of disease activity including relapse, disability progression and MRI findings. Clearly the effect of environmental factors on MS disease course is an area that requires significantly more research.

Air pollution and multiple sclerosis: a comprehensive review

Multiple sclerosis (MS) is an inflammatory, autoimmune demyelinating disorder of the central nervous system (CNS), leading to progressive functional impairments, and many intrinsic and acquired factors are believed to be associated with its development and relapse. In terms of environmental factors, air pollution has gained much attention during recent decades, as chronic exposure to ambient air pollution seems to increase the level of some pro-inflammatory markers in the human brain, which can lead to neuroinflammation, neurodegeneration, and blood-brain barrier (BBB) breakdown. These events may also be associated with the risk of MS development and relapse. In this review, we aimed to summarize recent findings around the impact of air pollutants, including particulate matter (PM10, PM2.5, and ultra-fine particles), gaseous pollutants (carbon monoxide [CO], nitrogen oxides [NO_x], sulfur dioxide [SO₂], and ozone [O₃]), and heavy metals, on MS development and relapse.

Fine Particulate Matter Related to Multiple Sclerosis Relapse in Young Patients

Objective: Particulate matter (PM) of aerodynamic diameter smaller than 10 μm (PM₁₀) has been associated with multiple sclerosis (MS) relapse. However, the impact of smaller PM with a greater ability to penetrate human organism has never been assessed. We evaluated the impact of PM smaller than 2.5 μm (PM_2.5) on the risk of MS relapse.

Material and Methods: In a case-crossover study, we included 2,109 consecutive hospitalizations likely due to MS relapse in day hospital in 5 MS centers in the Paris area from January 2009 to December 2013. For each hospitalization, the natural logarithm of the average weekly PM_2.5 concentrations (μg/m³) at the patient's residence address during each of the 6 weeks (week[0] to week[−5]) preceding admission was compared with the concentration during the previous week, using a conditional logistic regression adjusted on temperature, flu-like syndrome rate, pollen count, and holiday period.

Results: PM_2.5 average concentration during week[−3] was significantly associated with the risk of hospitalization for MS relapse [OR = 1.21 (CI 1.01;1.46)]. The association was stronger in patients younger than 30 years [OR=1.77 (CI 1.10; 2.83)].

Conclusion: Our study demonstrates an association between exposure to PM_2.5 and MS relapse, particularly in young people.

Association between air pollution and Multiple Sclerosis: A systematic review

Air pollution is a major public health threat. The present study is the first systematic review (SR) to determine the association of exposure to air pollution and Multiple Sclerosis (MS) Progression. A Literature search was carried out using relevant keywords within several international databases. A comprehensive literature search was carried out systematically and yielded 24 eligible studies concerning the relationship of exposure to air pollution including criteria air pollutants such as particulate matter, NOx and SOx, CO₂, traffic noise, etc. and MS disease. The results of the included studies reveal that there was a significant relationship between exposure to air pollution and MS development and progression. Although the effect of air pollution in the pathogenesis of MS is notfully known, according to the results of the included studies exposure to polluted air can stimulate several mechanisms that act as risk factors for developing MS and for having disease relapses or neurological disability. The major potential mechanism is Dysimmune inflammatory responses subsequent oxidative stress (OS), which leads to neuroinflammation and breakdown of the normal balance between immunity and self-tolerance. Air pollutants induce and sustain chemical reactions that produce reactive oxygen species (ROSs) and nitrogen reactive species (RNSs) which can initiate inflammatory cascades via the redox-sensitive mitogen-activated protein kinase (MAPK) and NF-κB that recruit and activate neutrophils, monocytes, and dendritic cells that stimulate the adaptive immune responses such as Th1 and Th17 inflammatory responses. The uncontrolled inflammatory responses following these events cause cell death and the release of self-antigens capable of stimulating the production of auto-aggressive T-cells via enhancing antigen presentation and facilitate entry of these cells to the central nervous system. Thus, oxidative stress is the culprit in the systemic inflammation and immune imbalance development and progression, powerful risk factors in MS.

Validation of an Algorithm to Detect Multiple Sclerosis Cases in Administrative Health Databases in Piedmont (Italy): An Application to the Estimate of Prevalence by Age and Urbanization Level

INTRODUCTION

Italy is considered a high-risk country for multiple sclerosis (MS). Exploiting electronic health archives (EHAs) is highly useful to continuously monitoring the prevalence of the disease, as well as the care delivered to patients and its outcomes. The aim of this study was to validate an EHA-based algorithm to identify MS patients, suitable for epidemiological purposes, and to estimate MS prevalence in Piedmont (North Italy).

METHODS

MS cases were identified, in the period between January 1, 2012 and December 31, 2017, linking data from 4 different sources: hospital discharges, drug prescriptions, exemptions from co-payment to health care, and long-term care facilities. Sensitivity of the algorithm was tested through record linkage with a cohort of 656 neurologist-confirmed MS cases; specificity was tested with a cohort of 2,966,293 residents presumably not affected by MS. Undercount was estimated by a capture-recapture method. We calculated crude, and age- and gender-specific prevalence. We also calculated age-adjusted prevalence by level of urbanization of the municipality of residence.

RESULTS

On December 31, 2017, the algorithm identified 8,850 MS cases. Sensitivity was 95.9%, specificity was 99.97%, and the estimated completeness of ascertainment was 91.9%. The overall prevalence, adjusted for undercount, was 152 per 100,000 among men and 286 among women; it increased with increasing age and reached its peak value in the 45- to 54-year class, followed by a progressive reduction. The age-adjusted prevalence of residents in cities was 15% higher than in those living in the countryside.

DISCUSSION/CONCLUSION

We validated an algorithm based on EHAs to identify cases of MS for epidemiological use. The prevalence of MS, adjusted for undercount, was among the highest in Italy. We also found that the prevalence was higher in highly urbanized areas.

Can particulate matter be identified as the primary cause of the rapid spread of CoViD-19 in some areas of Northern Italy?

Northern Italy was the most affected by CoViD-19 compared to other Italian areas and comprises zones where air pollutants concentration was higher than in the rest of Italy. The aim of the research is to determine if particulate matter (PM) has been the primary cause of the high CoViD-19 spread rapidity in some areas of Northern Italy. Data of PM for all the 41 studied cities were collected from the local environmental protection agencies. To compare air quality data with epidemiological data, a statistical analysis was conducted identifying the correlation matrices of Pearson and Spearman, considering also the possible incubation period of the disease. Moreover, a model for the evaluation of the epidemic risk, already proposed in literature, was used to evaluate a possible influence of PM on CoViD-19 spread rapidity. The results exclude that PM alone was the primary cause of the high CoVid-19 spread rapidity in some areas of Northern Italy. Further developments are necessary for a better comprehension of the influence of atmospheric pollution parameters on the rapidity of spread of the virus SARS-CoV-2, since a synergistic action with other factors (such as meteorological, socio-economic and cultural factors) could not be excluded by the present study.

Exposure to fine particulate matter (PM2.5) hampers myelin repair in a mouse model of white matter demyelination

Epidemiological studies show a strong association between exposure to air pollution - and particularly to particulate matter (PM) -, increased prevalence of Multiple Sclerosis (MS) and higher rates of hospital admissions for MS and MS relapses. Besides having immunomodulatory effects and sustaining a systemic oxidative-inflammatory response, PM may participate in MS pathogenesis by targeting also Central Nervous System (CNS)-specific processes, such as myelin repair. Here we show that, in a mouse model of lysolecithin-induced demyelination of the subcortical white matter, post-injury exposure to fine PM hampers remyelination, disturbs oligodendroglia differentiation dynamics and promotes astroglia and microglia reactivity. These findings support the view that exposure to fine PM can contribute to demyelinating pathologies by targeting the endogenous regenerative capability of the CNS tissue.

PM2.5 exposure as a risk factor for multiple sclerosis. An ecological study with a Bayesian mapping approach

Some environmental factors are associated with an increased risk of multiple sclerosis (MS). Air pollution could be a main one. This study was conducted to investigate the association of particulate matter 2.5 (PM_2.5) concentrations with MS prevalence in the province of Pavia, Italy. The overall MS prevalence in the province of Pavia is 169.4 per 100,000 inhabitants. Spatial ground-level PM_2.5 gridded data were analysed, by municipality, for the period 2010-2016. Municipalities were grouped by tertiles according to PM_2.5 concentration. Ecological regression and Bayesian statistics were used to analyse the association between PM_2.5 concentrations, degree of urbanization, deprivation index and MS risk. MS risk was higher among persons living in areas with an average winter PM_2.5 concentration above the European annual limit value (25 μg/m³). The Bayesian map revealed sizeable MS high-risk clusters. The study found a relationship between low MS risk and lower PM_2.5 levels, strengthening the suggestion that air pollution may be one of the environmental risk factors for MS.

Air Pollution and Central Nervous System Disease: A Review of the Impact of Fine Particulate Matter on Neurological Disorders

Background: It is widely known that the harmful effects of fine dust can cause various diseases. Research on the correlation between fine dust and health has been mainly focused on lung and cardiovascular diseases. By contrast, the effects of air pollution on the central nervous system (CNS) are not broadly recognized.

Findings: Air pollution can cause diverse neurological disorders as the result of inflammation of the nervous system, oxidative stress, activation of microglial cells, protein condensation, and cerebral vascular-barrier disorders, but uncertainty remains concerning the biological mechanisms by which air pollution produces neurological disease. Neuronal cell damage caused by fine dust, especially in fetuses and infants, can cause permanent brain damage or lead to neurological disease in adulthood.

Conclusion: It is necessary to study the air pollution–CNS disease connection with particular care and commitment. Moreover, the epidemiological and experimental study of the association between exposure to air pollution and CNS damage is critical to public health and quality of life. Here, we summarize the correlations between fine dust exposure and neurological disorders reported so far and make suggestions on the direction future research should take.

Geospatial Analysis of Environmental Atmospheric Risk Factors in Neurodegenerative Diseases: A Systematic Review

Despite the vast evidence on the environmental influence in neurodegenerative diseases, those considering a geospatial approach are scarce. We conducted a systematic review to identify studies concerning environmental atmospheric risk factors for neurodegenerative diseases that have used geospatial analysis/tools. PubMed, Web of Science, and Scopus were searched for all scientific studies that included a neurodegenerative disease, an environmental atmospheric factor, and a geographical analysis. Of the 34 included papers, approximately 60% were related to multiple sclerosis (MS), hence being the most studied neurodegenerative disease in the context of this study. Sun exposure (n = 13) followed by the most common exhaustion gases (n = 10 for nitrogen dioxide (NO₂) and n = 5 for carbon monoxide (CO)) were the most studied atmospheric factors. Only one study used a geospatial interpolation model, although 13 studies used remote sensing data to compute atmospheric factors. In 20% of papers, we found an inverse correlation between sun exposure and multiple sclerosis. No consensus was reached in the analysis of nitrogen dioxide and Parkinson’s disease, but it was related to dementia and amyotrophic lateral sclerosis. This systematic review (number CRD42020196188 in PROSPERO’s database) provides an insight into the available evidence regarding the geospatial influence of environmental factors on neurodegenerative diseases.

Air pollution as a contributor to the inflammatory activity of multiple sclerosis

OBJECTIVE

Air pollution has been recently identified as a risk factor for multiple sclerosis. Aim of this study was to investigate the immunological mechanism underlying the clinical association between air pollution, namely exposure to particulate matter 10 (PM10), and inflammatory activity of multiple sclerosis (MS) METHODS: Daily recording of PM10 was obtained by monitors depending on the residence of subjects. Expression of molecules involved in activation, adhesion, and migration of T lymphocytes were tested by flow cytometry in 57 MS patients and 19 healthy controls. We next assessed in vitro the effect of PM10 on expression of C-C chemokine receptors 6 (CCR6) by peripheral blood mononuclear cells (PBMCs), on cytokine production by monocyte-derived dendritic cells (mdDC), and on T cell polarization in PBMC/mdDC mixed cultures.

RESULTS

We identified a significant correlation between mean PM10 levels and expression of CCR6 CD4+ T circulating cells in MS patients. This was paralleled by the observation in vitro of a higher level of CCR6 expression on PBMC following treatment with increased doses of particulate matter. Moreover, in mdDC cultures, particulate matter induced the secretion by mdDC of Th17 polarizing IL1 beta, IL6, and IL23 and, in mdDC/PBMC mixed cultures, enhanced generation of IL17-producing T cells.

CONCLUSIONS

Ex vivo and in vitro studies support the pro-inflammatory role of PM in MS, by upregulating expression of CCR6 on circulating CD4+ T cells and inducing in innate immune cells the production of Th17 polarizing cytokines. Therefore, we speculate that in MS respiratory exposure to PM10 may induce the production in the lung of autoreactive Th17 lymphocytes and boost their migratory properties through the blood-brain barrier.

Air Pollution-Related Brain Metal Dyshomeostasis as a Potential Risk Factor for Neurodevelopmental Disorders and Neurodegenerative Diseases

Increasing evidence links air pollution (AP) exposure to effects on the central nervous system structure and function. Particulate matter AP, especially the ultrafine (nanoparticle) components, can carry numerous metal and trace element contaminants that can reach the brain in utero and after birth. Excess brain exposure to either essential or non-essential elements can result in brain dyshomeostasis, which has been implicated in both neurodevelopmental disorders (NDDs; autism spectrum disorder, schizophrenia, and attention deficit hyperactivity disorder) and neurodegenerative diseases (NDGDs; Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and amyotrophic lateral sclerosis). This review summarizes the current understanding of the extent to which the inhalational or intranasal instillation of metals reproduces in vivo the shared features of NDDs and NDGDs, including enlarged lateral ventricles, alterations in myelination, glutamatergic dysfunction, neuronal cell death, inflammation, microglial activation, oxidative stress, mitochondrial dysfunction, altered social behaviors, cognitive dysfunction, and impulsivity. Although evidence is limited to date, neuronal cell death, oxidative stress, and mitochondrial dysfunction are reproduced by numerous metals. Understanding the specific contribution of metals/trace elements to this neurotoxicity can guide the development of more realistic animal exposure models of human AP exposure and consequently lead to a more meaningful approach to mechanistic studies, potential intervention strategies, and regulatory requirements.