Multiple sclerosis incidence associated with the soil lead and arsenic concentrations in Taiwan

Gut microbiota in multiple sclerosis and animal models

Multiple sclerosis (MS) is a chronic central nervous system (CNS) neurodegenerative and neuroinflammatory disease marked by a host immune reaction that targets and destroys the neuronal myelin sheath. MS and correlating animal disease models show comorbidities, including intestinal barrier disruption and alterations of the commensal microbiome. It is accepted that diet plays a crucial role in shaping the microbiota composition and overall gastrointestinal (GI) tract health, suggesting an interplay between nutrition and neuroinflammation via the gut-brain axis. Unfortunately, poor host health and diet lead to microbiota modifications that could lead to significant responses in the host, including inflammation and neurobehavioral changes. Beneficial microbial metabolites are essential for host homeostasis and inflammation control. This review will highlight the importance of the gut microbiota in the context of host inflammatory responses in MS and MS animal models. Additionally, microbial community restoration and how it affects MS and GI barrier integrity will be discussed.

A genome-wide association study provides insights into the genetic etiology of 57 essential and non-essential trace elements in humans

Trace elements are important for human health but may exert toxic or adverse effects. Mechanisms of uptake, distribution, metabolism, and excretion are partly under genetic control but have not yet been extensively mapped. Here we report a comprehensive multi-element genome-wide association study of 57 essential and non-essential trace elements. We perform genome-wide association meta-analyses of 14 trace elements in up to 6564 Scandinavian whole blood samples, and genome-wide association studies of 43 trace elements in up to 2819 samples measured only in the Trøndelag Health Study (HUNT). We identify 11 novel genetic loci associated with blood concentrations of arsenic, cadmium, manganese, selenium, and zinc in genome-wide association meta-analyses. In HUNT, several genome-wide significant loci are also indicated for other trace elements. Using two-sample Mendelian randomization, we find several indications of weak to moderate effects on health outcomes, the most precise being a weak harmful effect of increased zinc on prostate cancer. However, independent validation is needed. Our current understanding of trace element-associated genetic variants may help establish consequences of trace elements on human health.

Appraisal of groundwater arsenic on opposite banks of River Ganges, West Bengal, India, and quantification of cancer risk using Monte Carlo simulations

This study was conducted to inspect the spatial distribution, source identification, and risk assessment of groundwater arsenic (As) in different blocks that lie on the opposite banks of river Bhagirathi (a distributary of river Ganges), Murshidabad, West Bengal, India. It has been observed that the blocks that lie towards the eastern bank of river Bhagirathi have elevated arsenic and comparatively more reducing groundwater (lower oxidation-reduction potential and high iron). About 66% of groundwater samples across the district have arsenic concentration higher than the World Health Organization (WHO) permissible limit. Speciation of groundwater arsenic reveals that about 90% of arsenic species were present as arsenic (III). Further, principal component analysis (PCA) was employed to identify the controlling factors that favor the release of arsenic. PC1 comprises EC, TDS, As, Fe, TOC, and HCO₃^- with moderate loadings, which suggests microbially mediated degradation of organic matter (OM), helps in reductive dissolution of arsenic-bearing Fe-Mn oxyhydroxides. Results pointed out severe groundwater arsenic poisoning; hence, a health risk assessment was performed for the exposure of arsenic in groundwater, using incremental lifetime cancer risk (ILCR) models coupled with Monte Carlo simulations. On the eastern bank of river Bhagirathi, incremental lifetime cancer risk (ILCR) due to oral exposure (5th to 95th percentile values) ranged from 1.30538E - 04 to 9.31398E - 03 with a mean of 2.84194E - 03 for adults, which is 2841 times higher than the USEPA high safety risk guidelines of one in 1 million. The outcomes of the results will be useful for the policymakers and regulatory boards in defining the actual impact and deciding the pre-remediation goals.

Searching for the Relationship between the Concentration of Heavy Metals in the Blood and the Clinical Course of Multiple Sclerosis: A Cross-Sectional Study in Poland

(1) Background: Of all environmental pollutants, heavy metals have the most detrimental effect on public health because they remain in the ecosystem and are not biodegradable. The neurotoxicity of heavy metals, including cadmium and lead, has been well documented, and blood levels of heavy metals serve as a biomarker of exposure, reflecting their content in soft tissues. Multiple sclerosis (MS) is one of the most common chronic neurodegenerative diseases. The pathogenesis of MS is complex and relies on the interaction between genetic and environmental factors. The aim of this study was to search for the relationship between the values of cadmium and lead concentration in the blood and the health history and functional status of patients with MS. (2) Methods: The study group consisted of 151 patients with a clinical diagnosis of MS. Determination of the presence of tested elements in serum was performed using an ELAN DRC-e ICP mass spectrometer. (3) Results: Statistical analysis demonstrated that an increase in the level of cadmium was accompanied by an increase in the level of lead. There was no significant correlation between the blood lead concentration and the functional status assessed by EDSS among patients with MS in Poland. However, a tendency towards worse functional status of patients with higher blood lead concentration (p = 0.07) was demonstrated. Patients who experienced first MS symptoms at older age had higher blood levels of the tested metals. (4) Conclusions: The concentrations of cadmium and lead in the blood of MS patients in Poland were not factors differentiating their functional status and the course of the disease.

Changes in DNA methylation in APOE and ACKR3 genes in multiple sclerosis patients and the relationship with their heavy metal blood levels

Multiple sclerosis (MS) is a chronic inflammatory disease with demyelinated lesions in the central nervous system caused by genetic and environmental factors. DNA methylation as an epigenetic change influenced by environmental factors, including heavy metals has been implemented in MS disease. We investigated the correlation of DNA methylation changes in APOE and ACKR3 genes in MS patients and the possible association with blood concentration of arsenic (As), cadmium (Cd) and lead (Pb) as major heavy metal pollutants. This study included 69 relapsing-remitting multiple sclerosis (RR-MS) patients and 69 age/gender-matched healthy subjects. The HRM real-time PCR method was used to investigate the changes in DNA methylation and heavy metal concentrations were measured by electrothermal atomic absorption spectrometry. Our results showed that the methylation pattern in the ACKR3 gene of the patient group was more hypomethylated, while in the case of the APOE gene, this pattern was more towards hypermethylation compared to healthy subjects. Moreover, the blood levels of As and Cd metals, but not Pb, were significantly higher in the patient group compare to the control group (p ≤ 0.05). The data indicate that the increase in expression of ACKR3 gene by hypomethylation and the decrease in expression of APOE gene via hypermethylation are possibly involved in the onset and progression of inflammatory processes in MS patients. The level of As can also lead to hypomethylation by disrupting the methylation patterns of the ACKR3 gene, resulting in increased expression in MS patients. Finally, we have shown that epigenetic changes can be an important factor in increasing and decreasing the expression of genes involved in the onset and/or progression of inflammatory processes in MS. Furthermore, exposure to heavy metals, especially As, by changing the natural patterns of DNA methylation can be effective in this disease.

Use of geographical information systems in multiple sclerosis research: A systematic scoping review

INTRODUCTION

Geographical information system (GIS) and spatial analysis have an emerging role in the understanding and management of health-related outcomes. However, there is a knowledge gap about the extent to which GIS has supported multiple Sclerosis (MS) research. Therefore, this review aimed to explore the types of GIS applications and the complexity of their visualisation in MS research.

METHODS

A systematic scoping review was conducted based on York's five-stage framework. PubMed, Scopus and Web of Science were searched for relevant studies published between 2000 and 2020 using a comprehensive search strategy based on the main concepts related to GIS and MS. Grounded, inductive analysis was conducted to organize studies into meaningful application areas. Further, we developed a tool to assess the visualisation complexity of the selected papers.

RESULTS

Of 3,723 identified unique citations, 42 papers met our inclusion criteria for the final review. One or more of the following types of GIS applications were reported by these studies: (a) thematic mapping (37 papers); (b) spatial cluster detection (16 papers); (c) risk factors detection (16 papers); and (d) health access and planning (two papers). In the majority of studies (88%), the score of visualisation complexity was relatively low: three or less from the range of zero to six.

CONCLUSIONS

Although the number of studies using GIS techniques has dramatically increased in the last decade, the use of GIS in the areas of MS access and planning is still under-researched. Additionally, the capacity of GIS in visualising complex nature of MS care system is not yet fully investigated.

Multiple sclerosis in Iran: An epidemiological update with focus on air pollution debate

BACKGROUND

Multiple sclerosis (MS), as the most common neurologic disorder of the central nervous system, with growing incidence and prevalence worldwide and in the Middle East. This article aimed to find out the potential relationship between MS and air pollution in Iran.

METHODS

By assessing the published articles on MS and air pollution in Iran, the situation of MS as well as air/soil pollution in Iran was clarified. Then, studies on air pollution and its potential effect on Iranian MS patients were checked until 2020.

RESULTS

The MS prevalence is distributed across Iran Provinces with highest rates in Isfahan, located in the center of Iran. The higher rates of MS in Isfahan and Tehran (the Metropolitan) might be due to industrial pollution of these cities, but this hypothesis is not true for non-industrial provinces. Based on the published atlas of MS in Iran, it seems that there is a high-risk "belt" from northwest to southeast.

CONCLUSION

There are many risk factors of MS in Iran including age, gender, Vitamin D deficiency, smoking, and air pollution. The potential main risk factor of MS might be air pollution considering Isfahan and Tehran provinces. However, Chahar Mahal and Bakhtiary Province, with non-industrial nature, has the second highest MS rates which does not follow this hypothesis.

RELEVANCE FOR PATIENTS

By finding the air pollution as the main potential risk factor of MS in big provinces including Isfahan and Tehran, its effect of this factor can also be considered during diagnosis and treatment.

Concentrations of toxic metals and essential trace elements vary among individual neurons in the human locus ceruleus

Objective

Damage to locus ceruleus neurons could play a part in the pathogenesis of neurodegenerative disorders such as Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis because of impairment of the blood-brain barrier and enhanced neuroinflammation. The locus ceruleus has connections throughout the brain and spinal cord, so the characteristic widespread multifocal pathology in these disorders could be due to damage to different subsets of locus ceruleus neurons. Previous studies have shown that only certain locus ceruleus neurons accumulate the neurotoxic metal mercury. To find out if concentrations of other toxic metals or of essential trace elements also vary between individual locus ceruleus neurons, we used synchrotron X-ray fluorescence microscopy on frozen sections of locus ceruleus neurons taken from people with multiple sclerosis, in whom the locus ceruleus is structurally intact.

Materials and methods

Paraffin embedded sections containing the locus ceruleus from seven people with multiple sclerosis were stained with autometallography that demonstrates accumulations of mercury, silver and bismuth. These were compared to maps of multiple elements obtained from frozen sections of locus ceruleus neurons from the same people using X-ray fluorescence microscopy. Neurons in the anterior pons from three of these donors were used as internal controls.

Results

Autometallography staining was observed in scattered locus ceruleus neurons from three of the seven donors. X-ray fluorescence microscopy showed variations among individual locus ceruleus neurons in levels of mercury, selenium, iron, copper, lead, bromine, and rubidium. Variations between donors of locus ceruleus neuronal average levels of mercury, iron, copper, and bromine were also detected. Anterior pons neurons contained no mercury, had varied levels of iron, and had lower copper levels than locus ceruleus neurons.

Conclusions

Individual human locus ceruleus neurons contain varying levels of toxic metals and essential trace elements. In contrast, most toxic metals are absent or at low levels in nearby anterior pons neurons. The locus ceruleus plays a role in numerous central nervous system functions, including maintaining the blood-brain-barrier and limiting neuroinflammation. Toxic metals, or alterations in essential trace metals within individual locus ceruleus neurons, could be one factor determining the non-random destruction of locus ceruleus neurons in normal aging and neurodegenerative diseases, and subsequently the sites of the widespread multifocal central nervous system pathology in these disorders.

Arsenic trioxide ameliorates experimental autoimmune encephalomyelitis in C57BL/6 mice by inducing CD4+ T cell apoptosis

BACKGROUND

Multiple sclerosis (MS) is an immune-mediated disease of the central nervous system characterized by severe white matter demyelination. Because of its complex pathogenesis, there is no definite cure for MS. Experimental autoimmune encephalomyelitis (EAE) is an ideal animal model for the study of MS. Arsenic trioxide (ATO) is an ancient Chinese medicine used for its therapeutic properties with several autoimmune diseases. It is also used to inhibit acute immune rejection due to its anti-inflammatory and immunosuppressive properties. However, it is unclear whether ATO has a therapeutic effect on EAE, and the underlying mechanisms have not yet been clearly elucidated. In this study, we attempted to assess whether ATO could be used to ameliorate EAE in mice.

METHODS

ATO (0.5 mg/kg/day) was administered intraperitoneally to EAE mice 10 days post-immunization for 8 days. On day 22 post-immunization, the spinal cord, spleen, and blood were collected to analyze demyelination, inflammation, microglia activation, and the proportion of CD4+ T cells. In vitro, for mechanistic studies, CD4+ T cells were sorted from the spleen of naïve C57BL/6 mice and treated with ATO and then used for an apoptosis assay, JC-1 staining, imaging under a transmission electron microscope, and western blotting.

RESULTS

ATO delayed the onset of EAE and alleviated the severity of EAE in mice. Treatment with ATO also attenuated demyelination, alleviated inflammation, reduced microglia activation, and decreased the expression levels of IL-2, IFN-γ, IL-1β, IL-6, and TNF-α in EAE mice. Moreover, the number and proportion of CD4+ T cells in the spinal cord, spleen, and peripheral blood were reduced in ATO-treated EAE mice. Finally, ATO induced CD4+ T cell apoptosis via the mitochondrial pathway both in vitro and in vivo. Additionally, the administration of ATO had no adverse effect on the heart, liver, or kidney function, nor did it induce apoptosis in the spinal cord.

CONCLUSIONS

Overall, our findings indicated that ATO plays a protective role in the initiation and progression of EAE and has the potential to be a novel drug in the treatment of MS.

Incidence of multiple sclerosis in the province of Catania. A geo-epidemiological study

BACKGROUND

An increasing incidence of MS in the city of Catania was reported during 1975-2004, with a higher incidence along the south-eastern flank of the Mt.Etna. We evaluated the incidence of MS in the entire province of Catania during 2005-2015 and the spatial distribution of MS-cases using a cluster analysis.

METHODS

Patients were considered as incident MS-cases if they fulfilled the revised McDonald criteria for MS during 2005-2015 and were residents in the province of Catania at the time of disease onset. Cluster analysis was performed using both LISA and Kulldorff's spatial scan statistic. Residence address at disease onset was considered for each case. Communalities were assessed considering the centroid of their inhabited area.

RESULTS

A total of 973 MS-cases were identified. Mean annual incidence risk was 8.2/100,000 person-years (95%CI 7.7-8.7), significantly higher among women (10.5/100,000 versus 5.7/100,000). LISA identified a spatial aggregation of MS-cases in the eastern side of the province of Catania and Kulldorff's statistics confirmed the existence of a statistically significant spatial cluster in this area (SIR 1.23,95%CI 1.08-1.23, p-value 0.04).

CONCLUSIONS

Our study confirms a high incidence of MS in the province of Catania and the presence of a spatial cluster along the eastern side of the province. This area is considered the most exposed to volcanogenic ashes due to the prevailing westerly to north-westerly trade winds. Even if such distribution could be related with a greater exposure to volcanogenic metals, further studies are needed to explore possible alternative hypotheses.

The Beneficial and Debilitating Effects of Environmental and Microbial Toxins, Drugs, Organic Solvents and Heavy Metals on the Onset and Progression of Multiple Sclerosis

Multiple sclerosis (MS), a chronic inflammatory disease of the central nervous system is common amongst young adults, leading to major personal and socioeconomic burdens. However, it is still considered complex and challenging to understand and treat, in spite of the efforts made to explain its etiopathology. Despite the discovery of many genetic and environmental factors that might be related to its etiology, no clear answer was found about the causes of the illness and neither about the detailed mechanism of these environmental triggers that make individuals susceptible to MS. In this review, we will attempt to explore the major contributors to MS autoimmunity including genetic, epigenetic and ecological factors with a particular focus on toxins, chemicals or drugs that may trigger, modify or prevent MS disease.

Blood lead levels and multiple sclerosis: A case-control study

BACKGROUND

Multiple sclerosis (MS) is a debilitating disease of the central nervous system, with disseminating demyelination of nerve fibers and spinal cord. Exposure to heavy metals seems to be associated with a higher incidence of MS. Few studies have assessed the correlation of the incidence of MS with heavy metal concentrations. The present study aimed to assess the relationship between blood lead levels and MS.

METHODS

This case-control study was conducted on 29 MS patients and 29 healthy control persons. The controls were age, gender and occupation matched at the time of blood sampling. Blood lead levels were measured using the atomic absorption spectrometry method. Data were analyzed using Student t-test, Mann-Whitney U, and multiple logistic regression, using a significance level of p ˂ 0.05.

RESULTS

According to the result of this study, the mean blood lead level (BLL) was 75.6 ± 9.35and33.8 ± 28.8 µg/L in patients with MS and control group, respectively. Median blood lead levels were significantly higher in MS patients (38 µg/L, range: 27-67), compared to the controls (30 µg/L, range: 11-49) (p = 0.03). The risk of MS increased 1.17 times per one µg/L increment of blood lead level, using the multiple logistic regression analysis on the present results.

CONCLUSION

In conclusion, based on our results, BLL was higher in MS patients, compared with healthy individuals. The risk of MS increased 1.17 times per one µg/L increment of blood lead level.

Smoking under hypoxic conditions: a potent environmental risk factor for inflammatory and autoimmune diseases

Autoimmune disease management presents a significant challenge to medical science. Environmental factors potentially increase the risk of developing inflammatory and autoimmune diseases, such as multiple sclerosis, rheumatoid arthritis, and lupus. Among various environmental stresses, cigarette smoke and hypoxia have both been reported to lead to an enhanced risk of inflammatory and autoimmune diseases.In this review, we shed light on all reported mechanisms whereby cigarette smoke and a hypoxic environment can induce inflammatory and autoimmune diseases and discuss how hypoxic conditions influence the cigarette smoke-induced threat of inflammatory and autoimmune disease development.Cigarette smoke and hypoxia both lead to increased oxidative stress and production of reactive oxygen species and other free radicals, which have various effects including the generation of autoreactive pro-inflammatory T cells and autoantibodies, reductions in T regulatory (Treg) cell activity, and enhanced expression of pro-inflammatory mediators [e.g., interleukin-6 (IL-6), interleukin-4 (IL-4) and interleukin-8 (IL-8)]. Accordingly, smoking and hypoxic environments may synergistically act as potent environmental risk factors for inflammatory and autoimmune diseases. To our knowledge, no studies have reported the direct association of cigarette smoke and hypoxic environments with the risk of developing inflammatory and autoimmune diseases.Future studies exploring the risk of autoimmune disease development in smokers at high altitudes, particularly military personnel and mountaineers who are not acclimatized to high-altitude regions, are required to obtain a better understanding of disease risk as well as its management.

Evaluation of serum arsenic and its effects on antioxidant alterations in relapsing-remitting multiple sclerosis patients

BACKGROUND

Environmental factors that are involved in the development of autoimmune diseases include bacteria, viruses, and xenobiotics such as chemicals, drugs, and metals. Regarding the metals, a number of studies have demonstrated that oxidative stress is one of the well-directed pathways of arsenic-induced tissue damages. This study was designed to explore the serum concentrations of arsenic and its correlation with markers associated with oxidative stress in relapsing-remitting MS (RRMS) patients.

METHODS

This case-controlled study comprised 50 patients with RRMS and 50 healthy subjects. Serum arsenic levels, total antioxidant potential, malondialdehyde (MDA), and lactate levels were measured.

RESULTS

The arsenic value, MDA, and lactate levels were elevated meaningfully while FRAP level significantly was decreased in RRMS patients with respect to healthy subjects (P <0.05). Furthermore, arsenic serum levels were positively correlated with serum concentrations of MDA and lactate. In contrast, serum levels were negatively correlated to FRAP values in RRMS patients.

CONCLUSION

Taken together, the association between arsenic level and oxidative stress parameters supports the hypothesis that high serum arsenic levels may play a critical role in the pathogenesis of MS progression.

Assessment of Heavy Metal Pollution and Health Risks in the Soil-Plant-Human System in the Yangtze River Delta, China

Heavy metal (HM) contamination and accumulation is a serious problem around the world due to the toxicity, abundant sources, non-biodegradable properties, and accumulative behaviour of HMs. The degree of soil HM contamination in China, especially in the Yangtze River Delta, is prominent. In this study, 1822 pairs of soil and crop samples at corresponding locations were collected from the southern Yangtze River Delta of China, and the contents of Ni, Cr, Zn, Cd, As, Cu, Hg, and Pb were measured. The single pollution index in soil (SPI) and Nemerow composite pollution index (NCPI) were used to assess the degree of HM pollution in soil, and the crop pollution index (CPI) was used to explore the degree of HM accumulation in crops. The bioaccumulation factor (BAF) was used to investigate the translocation of heavy metals in the soil-crop system. The health risks caused by HMs were calculated based on the model released by the U.S. Environmental Protection Agency. The SPIs of all elements were at the unpolluted level. The mean NCPI was at the alert level. The mean CPIs were in the following decreasing order: Ni (1.007) > Cr (0.483) > Zn (0.335) > Cd (0.314) > As (0.232) > Cu (0.187) > Hg (0.118) > Pb (0.105). Only the mean content of Ni in the crops exceeded the national standard value. The standard exceeding rates were used to represent the percentage of samples whose heavy metal content is higher than the corresponding national standard values. The standard exceeding rates of Cu, Hg, and Cd in soil were significantly higher than corresponding values in crops. Meanwhile, the standard exceeding rates of Ni, As, and Cr in crops were significantly higher than corresponding values in soil. The chronic daily intake (CDI) of children (13.8 × 10^-3) was the largest among three age groups, followed by adults (6.998 × 10^-4) and seniors (5.488 × 10^-4). The bioaccumulation factors (BAFs) of all crops followed the order Cd (0.249) > Zn (0.133) > As (0.076) > Cu (0.064) > Ni (0.018) > Hg (0.011) > Cr (0.010) > Pb (0.001). Therefore, Cd was most easily absorbed by crops, and different crops had different capacities to absorb HMs. The hazard quotient (HQ) represents the potential non-carcinogenic risk for an individual HM and it is an estimation of daily exposure to the human population that is not likely to represent an appreciable risk of deleterious effects during a lifetime. All the HQs of the HMs for the different age groups were significantly less than the alert value of 1.0 and were at a safe level. This indicated that citizens in the study area face low potential non-carcinogenic risk caused by HMs. The total carcinogens risks (TCRs) for children, adults, and seniors were 5.24 × 10^-5, 2.65 × 10^-5, and 2.08 × 10^-5, respectively, all of which were less than the guideline value but at the alert level. Ingestion was the main pathway of carcinogen risk to human health.

Assessment of the potential health risks of heavy metals in soils in a coastal industrial region of the Yangtze River Delta

Soil heavy metal contamination is a serious environmental problem. Human beings may be directly exposed to heavy metals in soils through the inhalation of soil particles, dermal contact, and oral ingestion, which can seriously threaten health. This study assesses the health risks associated with heavy metals in soils by determining the concentrations of eight heavy metals (Cr, Pb, Cd, Hg, As, Cu, Zn, and Ni) based on 2051 surface-soil samples collected from the southern Yangtze River Delta of China. The mean concentrations were higher than the corresponding background values in Zhejiang Province and China as a whole, indicating an accumulation of heavy metals. The health risk assessment suggests that the non-carcinogenic and carcinogenic risks in the study area were not significant. The non-carcinogenic risk for children was the highest, followed by those for adults and seniors; the non-carcinogenic risk for the entire population was less than 1.0, the predetermined threshold. Carcinogenic risk for adults was the highest, followed by those for seniors and children; a few sample points had a value larger than the threshold of 1.0E-04. Arsenic represented the greatest contribution to non-carcinogenic and carcinogenic risk. Meanwhile, ingestion of heavy metals in soil was the main exposure pathway for carcinogenic risk, followed by inhalation and dermal exposure. The spatial method of Getis-Ord was used to identify hot spots of health risk. Hot spots with high hazard index (HI) and total carcinogenic risk (TCR) for children, adults, and seniors were mainly distributed in core urban areas, such as Jiangbei, Haishu, Yinzhou, Jiangdong, and the urban areas of some other counties, which coincided with industrial, mining, and urban areas of the study area and were strongly influenced by anthropogenic activities. These results provide a basis for heavy metal control in soil, source identification, and environment management in the Yangtze River Delta and other rapidly developing industrial regions in China.

Type 1 diabetes in Sardinia: facts and hypotheses in the context of worldwide epidemiological data

Type 1 diabetes (T1D) results from an autoimmune destruction of insulin-producing beta cells that requires lifelong insulin treatment. While significant advances have been achieved in treatment, prevention of complications and quality of life in diabetic people, the identification of environmental triggers of the disease is far more complex. The island of Sardinia has the second highest incidence of T1D in the world (45/100,000), right after Finland (64.2/100,000). The genetic background as well as the environment of the island's inhabitants makes it an ideal region for investigating environmental, immunological and genetic factors related to the etiopathogenesis of T1D. Several epidemiological studies, conducted over the years, have shown that exposures to important known environmental risk factors have changed over time, including nutritional factors, pollution, chemicals, toxins and infectious diseases in early life. These environmental risk factors might be involved in T1D pathogenesis, as they might initiate autoimmunity or accelerate and precipitate an already ongoing beta cell destruction. In terms of environmental factors, Sardinia is also particular in terms of the incidence of infection with Mycobacterium avium paratuberculosis (MAP) that recent studies have linked to T1D in the Sardinian population. Furthermore, the unique geochemical profile of Sardinia, with its particular density of heavy metals, leads to the assumption that exposure of the Sardinian population to heavy metals could also affect T1D incidence. These factors lead us to hypothesize that T1D incidence in Sardinia may be affected by the exposure to multifactorial agents, such as MAP, common viruses and heavy metals.

The hypothetical roles of arsenic in multiple sclerosis by induction of inflammation and aggregation of tau protein: A commentary

Multiple sclerosis (MS) is a disease which manifests demyelination of neuronal cells in the brain. Despite extensive research on the mechanisms of disease development and progression, the exact mechanism is not elucidated yet, which has hampered drug development and subsequent treatment of the disease. We have recently shown that the serum levels of arsenic and malondialdehyde, a lipid peroxidation marker, are high in MS patients. In this article, we would like to formulate the hypothesis that arsenic may cause MS by induction of inflammation, degeneration, and apoptosis in neuronal cells. The induction of ROS generation in cells upon exposure to arsenic as a heavy metal may be involved in the pathogenesis of MS. Tau protein, a member of the family of microtubule-associated proteins, is mainly expressed in neurons and contribute to the assembly of neuronal microtubules network. Arsenic may affect the hyperphosphorylation and aggregation of tau proteins and may be involved in the cascade leading to deregulation of tau function associated with neurodegeneration. For validation of this hypothesis, studies might be conducted to evaluate the association of arsenic levels and tau protein levels in MS patients. Further studies might also focus on the trafficking along microtubules in neurons of MS patient with regard to hyperphosphorylation of tau protein. This hypothesis may add a new dimension to the understanding of MS etiology and help to design novel therapeutic agents against potential targets that might be discovered. If this hypothesis proves to be true, tau phosphorylation inhibitors can be potential candidates for MS drug development.

Soil heavy metals are associated with the distribution of multiple sclerosis in Isfahan, Iran

BACKGROUND

Few epidemiological studies have explored the effects of soil pollution on multiple sclerosis (MS) risk in Asia.

METHOD

Based on catchment areas, Isfahan province is divided into five regions (Central, North, East, West, and South), and Soil sampling performed in catchment area with the highest range of MS prevalence and incidence. Samples were analyzed for cobalt (Co), lead (Pb), cadmium (Cd), copper (Cu), zinc (Zn), and absorbable forms of Pb, Cd, and Co. Linear regression is used to examine the association of soil heavy metals with prevalence of MS in central part of Isfahan province.

RESULT

Multiple sclerosis prevalence ranged from 5.62 to 156.65 in different townships. Based on regression analysis, in case of considering fixed amounts for the rest of elements, a one (SD) increase of absorbable Pb and absorbable Cd are associated with 0.385 (SD) (P < 0.0001) increase and 0.209 (SD) (P < 0.007) decrease in MS prevalence, respectively.

CONCLUSION

This study documented a significant association between exposure to absorbable Pb and Cd in soil with prevalence of MS in Isfahan. Further work is warranted to confirm this association and if validated, to understand the mechanisms behind the association.

Is Geo-Environmental Exposure a Risk Factor for Multiple Sclerosis? A Population-Based Cross-Sectional Study in South-Western Sardinia

Background

South-Western Sardinia (SWS) is a high risk area for Multiple Sclerosis (MS) with high prevalence and spatial clustering; its population is genetically representative of Sardinians and presents a peculiar environment. We evaluated the MS environmental risk of specific heavy metals (HM) and geographical factors such as solar UV exposure and urbanization by undertaking a population-based cross-sectional study in SWS.

Methods

Geochemical data on HM, UV exposure, urbanization and epidemiological MS data were available for all SWS municipalities. Principal Component Analysis (PCA) was applied to the geochemical data to reduce multicollinearity and confounding criticalities. Generalized Linear Mixed Models (GLMM) were applied to evaluate the causal effects of the potential risk factors, and a model selection was performed using Akaike Information Criterion.

Results

The PCA revealed that copper (Cu) does not cluster, while two component scores were extracted: 'basic rocks', including cobalt, chromium and nickel, and 'ore deposits', including lead and zinc. The selected multivariable GLMM highlighted Cu and sex as MS risk factors, adjusting for age and 'ore deposits'. When the Cu concentration increases by 50 ppm, the MS odds are 2.827 (95% CI: 1.645; 5.07) times higher; females have a MS odds 2.04 times (95% CI: 1.59; 2.60) higher than males.

Conclusions

The high frequency of MS in industrialized countries, where pollution by HM and CO poisoning is widespread, suggests a relationship between environmental exposure to metals and MS. Hence, we suggested a role of Cu homeostasis in MS. This is a preliminary study aimed at generating hypotheses that will need to be confirmed further.

Heavy metals and neurodegenerative diseases: an observational study

In this study, we evaluated the levels of some of the most investigated metals (Cu, Se, Zn, Pb, and Hg) in the blood of patients affected by the most common chronic neurodegenerative diseases like Alzheimer's disease (AD) and multiple sclerosis (MS), in order to better clarify their involvement. For the first time, we investigated a Sicilian population living in an area exposed to a potentially contaminated environment from dust and fumes of volcano Etna and consumer of a considerable quantity of fish in their diet, so that this represents a good cohort to demonstrate a possible link between metals levels and development of neurodegenerative disorders. More specifically, 15 patients affected by AD, 41 patients affected by MS, 23 healthy controls, and 10 healthy elderly controls were recruited and subjected to a venous blood sampling. Quantification of heavy metals was performed by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). This technique has allowed us to establish that there is a concomitance of heavy metal unbalance associated with AD more than in other neurodegenerative pathologies, such as MS. Also, we can assess that the concentration of these elements is independent from the diet, especially from occasional or habitual consumption of fruits and vegetables, prevalence in the diet of meat or fish, possible exposure to contaminated environment due both to the occupation and place of residence.

Beta2-adrenergic agonist use and the risk of multiple sclerosis: a total population-based case-control study

OBJECTIVE

The aim of this study was to investigate whether the use of fenoterol, a beta2-adrenergic agonist, was associated with multiple sclerosis (MS) risk by conducting a total population-based case-control study in Taiwan.

METHODS

A total of 578 patients with newly diagnosed MS who had a severely disabling disease (SDD) certificate between January 1, 2002 and December 1, 2008 comprised the case group. These cases were compared with 2890 gender-, age-, residence-, and insurance premium-matched controls. Fenoterol use was analyzed using a conditional logistic regression model that controlled for asthma, chronic obstructive pulmonary disease (COPD), salbutamol and steroid use.

RESULTS

Compared with the group of people who did not use fenoterol, the adjusted odds ratios were 0.67 (95% confidence interval (CI) = 0.48-0.93, p = 0.016) for the group prescribed fenoterol below 2.25 cumulative defined daily dose (cDDD) and 0.49 (95% CI = 0.33-0.71, p < 0.001) for the group with a cumulative fenoterol use of more than 2.25 cDDD. The dose-response relationship was similar within the non-asthma patients. The associations were similar between males and females, but differences between age groups were observed.

CONCLUSIONS

The results of this study suggest that fenoterol use may reduce the risk of MS.