Systemic sclerosis and exposure to heavy metals

Mercury Exposure and Health Effects: What Do We Really Know?

Mercury is widely used in medicine, agriculture, and industry. Meanwhile, according to the World Health Organization, it has been ranked as one of the ten most hazardous substances in the world, with the Agency for Toxic Substances and Disease Registry ranking it third. It has no known positive functionality in the human body, and even at low concentrations, it can have harmful long-term health effects, seriously affecting the healthcare system as well as posing a serious public health threat. This review focuses on the health effects of mercury and its major sources in the environment. We highlight its major toxic role in almost every possible aspect. Mercury and its forms, even in the smallest doses, cause numerous disorders to the body, including to the nervous system, the respiratory system, and the cardiovascular system. It can cause disorders such as various cancers; endothelial dysfunction; gastric and vascular disorders; liver, kidney, and brain damage; hormonal imbalances, miscarriages, and reproductive disorders; skin lesions; vision damage; and even death. The fact of such widespread use as well as its toxicity to the human body prompts further and in-depth research in populations of both low and moderate exposure. The constant controlling and monitoring of mercury use is a serious public health problem, requiring urgent attention and attentiveness from the governments of all countries and, in the long run, a rapid and concerted response. Thus, it is important to analyze in depth the impact of this highly toxic metal on the human body and to prepare the most precisely targeted public health interventions among all decision- and policy-makers.

External and internal exposome as triggers of biological signalling in systemic sclerosis - A narrative synthesis

Systemic sclerosis (SSc) is an autoimmune chronic connective tissue disorder with a complex pathogenesis and a strong gene-environment interaction. Despite the low prevalence of SSc, with around 100-250 cases per million, the morbidity and mortality are high and disproportionately affecting women. In this context, we review the influence of the external and internal exposome on the "immunome" in SSc. While several studies have addressed aspects of exposure-induced autoimmunity in general, very few have focused on SSc-specific phenotypes. In epidemiological studies, targeted characterization of the external exposome component in relation to SSc has often been limited to a single exposure. Despite the selective characterization of exposure, such studies play an important role in providing evidence that can be used towards reduction of exposure of modifiable factors, and can lead to proper management and prevention of SSc. Additionally, there is an effort towards integration of external exposome data with health data (health records, medical imaging, diagnostic results, etc.), to significantly improve our understanding of the environmental and occupational causes of SSc. A limited number of studies have identified biological processes related to the vascular homeostasis, fibrotic processes and the immune system. The key findings of the current review show advances in our understanding of the SSc disease phenotype and associated biomarkers in relation to specific pathophysiological features, however most often such studies are not supplemented with external exposome data.

Anthropogenic-induced environmental and ecological changes in the Nile Delta over the past half-century

Anthropogenic activities over the past half-century have had a negative impact on the wetland ecosystem in the Nile Delta, which provides essential provisioning and regulating services. Therefore, it is crucial to systematically investigate pollution levels and their ecological consequences at both spatial and temporal scales in order to promote sustainable development. In this study, data on metal pollution in the Manzala Lake were compiled through a systematic review of all published literature from 1968 to 2020. Additionally, agricultural data (including land use, pesticide and fertilizer usage, and discharge) and economic data for the same time period were collected to identify the main drivers of pollution. The results indicated an overall increasing trend in heavy metal concentrations during the study period. The average concentrations of metals, arranged in descending order, were as follows: Fe (15,115.5 μg/g) > Mn (722 μg/g) > Zn (115.4 μg/g) > Cu (65.9 μg/g) > Ni (62.5 μg/g) > Cr (58.1 μg/g) > Pb (54.1 μg/g) > Cd (4.7 μg/g) > Hg (0.1 μg/g). A linear regression model revealed that wastewater discharge, water reuse, and the use of pesticides and fertilizers are the main sources of heavy metal pollution in the Manzala Lake. Consequently, there has been a dramatic decrease in the biodiversity of fish and molluscan communities. The study also found a correlation between heavy metal pollution and socio-economic development, highlighting the urgent need for attention to the conservation, management, and sustainable development of the lake.

Immunogenetics of Systemic Sclerosis

Systemic sclerosis (SSc) is a rare autoimmune connective tissue disorder characterized by massive fibrosis, vascular damage, and immune imbalance. Advances in rheumatology and immunology over the past two decades have led to a redefinition of systemic sclerosis, shifting from its initial perception as primarily a "hyperfibrotic" state towards a recognition of systemic sclerosis as an immune-mediated disease. Consequently, the search for genetic markers has transitioned from focusing on fibrotic mechanisms to exploring immune regulatory pathways. Immunogenetics, an emerging field at the intersection of immunology, molecular biology, and genetics has provided valuable insights into inherited factors that influence immunity. Data from genetic studies conducted thus far indicate that alterations in genetic messages can significantly impact disease risk and progression. While certain genetic variations may confer protective effects, others may exacerbate disease susceptibility. This paper presents a comprehensive review of the most relevant genetic changes that influence both the risk and course of systemic sclerosis. Special emphasis is placed on factors regulating the immune response, recognizing their pivotal role in the pathogenesis of the disease.

A Narrative Review of Pathogenetic and Histopathologic Aspects, Epidemiology, Classification Systems, and Disease Outcome Measures in Systemic Sclerosis

Systemic sclerosis (SSc) is a rare systemic autoimmune disease, characterized by the presence of three main actors: vasculopathy, immune activation, and fibrosis. This pathologic process is then translated in a clinical picture with great variability among different patients in terms of type of organ involvement, disease severity and prognosis. This heterogeneity is a main feature of SSc, which, in addition to the presence of early phases of the disease characterized by mild symptoms, can explain the high difficulty in establishing classification criteria, and in defining patients' subsets and disease outcomes. The definition of disease outcomes is particularly relevant in the setting of clinical trials, where the aim is to provide reliable endpoints, able to measure the magnitude of the efficacy of a certain drug or intervention. For this reason, in the last years, increasing efforts have been done to design measures of disease activity, damage, severity, and response to treatment, often in the context of composite indexes. When considering disease outcomes, the experience of the patient represents a relevant and complementary aspect. The tools able to capture this experience, the patient-reported outcomes, have been increasingly used in the last years in clinical practice and in clinical trials, both as primary and secondary endpoints. This comprehensive narrative review on SSc will therefore cover pathogenetic and histopathologic aspects, epidemiology, classification systems, and disease outcome measures, in order to focus on issues that are relevant for clinical research and design of clinical trials.

Serum autoantibodies and exploratory molecular pathways in rural miners: A pilot study

Introduction

The Southwestern United States (SWUS) has an extensive history of coal and metal mining, including uranium (U) mining. Lung diseases, including but not limited to, lung cancer and pulmonary fibrosis, have been studied extensively in miners due to occupational, dust-related exposures. However, high-throughput autoimmune biomarkers are largely understudied in miners, despite the fact that ore miners, such as U-miners, are at an increased risk for the development of autoimmune diseases such as systemic sclerosis and systemic lupus erythematosus (SLE). Additionally, there are current gaps in knowledge regarding which signaling pathways may play a role in occupational exposure-associated autoimmunity.

Methods

Most current and former miners in the SWUS live close to their previous workplaces, in remote areas, with limited access to healthcare. In this pilot study, by leveraging a mobile clinical platform for patient care and clinical outreach, we recruited 44 miners who self-identified as either U (n = 10) or non-U miners (n = 34) and received health screenings. Serum IgG and IgM autoantibodies against 128 antigens were assessed using a high-throughput molecular technique, as a preliminary health screening opportunity.

Results

Even when adjusting for age as a covariate, there was a significant (p < 0.05) association between self-reported U-mining exposure and biomarkers including IgM alpha-actinin, histones H2B, and H4, myeloperoxidase (MPO) and myelin basic protein. However, adjusting for age did not result in significant associations for IgG autoantibody production in U-miners. Bioinformatic pathway analysis revealed several altered signaling pathways between IgM and IgG autoantibodies among both U and non-U miners.

Conclusions

Further research is warranted regarding the mechanistic connection between U-exposure and autoantibody development, especially regarding histone-related alterations and IgM autoantibody production.

Cadmium contributes to atherosclerosis by affecting macrophage polarization

Chronic cadmium (Cd) exposure contributes to the progression of atherosclerosis, but the direct role of Cd and its mechanisms in atherosclerosis remains incompletely understood. Atherosclerosis is a chronic inflammatory disease promoting macrophage polarization to M1 phenotype and producing pro-inflammations that are vital in regulating the inflammatory response. Herein, through a case-control study, we found that Cd exposure may promote the occurrence of carotid plaque via inflammation, where interleukin-6 (IL-6) may play an important role. We also combined in vivo and in vitro experiments to explore the underlying mechanism of Cd-promoted plaque formation and the production of IL-6. With or without cadmium chloride (CdCl₂) fed ApoE^-/- mouse and treated RAW264.7 cells, we found Cd accumulated in the aortas which significantly increased the plaque area in atherosclerotic mice, macrophage accumulation, and lipid accumulation, and Cd promoted M1 phenotype macrophage polarization reflected by the increased expression of CD86 which produced tumor necrosis factor-α (TNF-α) and IL-6. However, the influences on M2 phenotype and anti-inflammatory cytokines interleukin-4 (IL-4) and interferon-γ (IFN-γ) were non-significant. Moreover, we found that JAK2/STAT3 pathway was greatly activated in the plaques and CdCl₂-treated macrophages. The inhibition of JAK2/STAT3 substantially reversed the Cd-stimulated macrophage M1 phenotype macrophage polarization and the expression of pro-inflammatory cytokines including TNF-α and IL-6. Altogether, Cd intensifies atherosclerosis by modulating macrophage polarization via JAK2/STAT3 to up-regulated the expression of IL-6.

Environmental Risks for Systemic Sclerosis

There is an increasing body of literature suggesting a relationship between environmental factors and the development of systemic sclerosis (SSc). These include occupational exposures, chemical materials, medications, alterations in the microbiome, and dysbiosis. Environmental exposures may impact epigenetic regulation thereby triggering an aberrant immune response resulting in the clinical and serologic phenotype that we diagnose as SSc. Screening and studying putative triggers will not only improve our understanding of the pathogenesis of SSc but also inform the institution for protective measures.

Animal Models of Systemic Sclerosis: Using Nailfold Capillaroscopy as a Potential Tool to Evaluate Microcirculation and Microangiopathy: A Narrative Review

Systemic sclerosis (SSc) is an autoimmune disease with three pathogenic hallmarks, i.e., inflammation, vasculopathy, and fibrosis. A wide plethora of animal models have been developed to address the complex pathophysiology and for the development of possible anti-fibrotic treatments. However, no current model comprises all three pathological mechanisms of the disease. To highlight the lack of a complete model, a review of some of the most widely used animal models for SSc was performed. In addition, to date, no model has accomplished the recreation of primary or secondary Raynaud’s phenomenon, a key feature in SSc. In humans, nailfold capillaroscopy (NFC) has been used to evaluate secondary Raynaud’s phenomenon and microvasculature changes in SSc. Being a non-invasive technique, it is widely used both in clinical studies and as a tool for clinical evaluation. Because of this, its potential use in animal models has been neglected. We evaluated NFC in guinea pigs to investigate the possibility of applying this technique to study microcirculation in the nailfold of animal models and in the future, development of an animal model for Raynaud’s phenomenon. The applications are not only to elucidate the pathophysiological mechanisms of vasculopathy but can also be used in the development of novel treatment options.

Molecular Basis of Accelerated Aging with Immune Dysfunction-Mediated Inflammation (Inflamm-Aging) in Patients with Systemic Sclerosis

Systemic sclerosis (SSc) is a chronic connective tissue disorder characterized by immune dysregulation, chronic inflammation, vascular endothelial cell dysfunction, and progressive tissue fibrosis of the skin and internal organs. Moreover, increased cancer incidence and accelerated aging are also found. The increased cancer incidence is believed to be a result of chromosome instability. Accelerated cellular senescence has been confirmed by the shortening of telomere length due to increased DNA breakage, abnormal DNA repair response, and telomerase deficiency mediated by enhanced oxidative/nitrative stresses. The immune dysfunctions of SSc patients are manifested by excessive production of proinflammatory cytokines IL-1, IL-6, IL-17, IFN-α, and TNF-α, which can elicit potent tissue inflammation followed by tissue fibrosis. Furthermore, a number of autoantibodies including anti-topoisomerase 1 (anti-TOPO-1), anti-centromere (ACA or anti-CENP-B), anti-RNA polymerase enzyme (anti-RNAP III), anti-ribonuclear proteins (anti-U1, U2, and U11/U12 RNP), anti-nucleolar antigens (anti-Th/T0, anti-NOR90, anti-Ku, anti-RuvBL1/2, and anti-PM/Scl), and anti-telomere-associated proteins were also found. Based on these data, inflamm-aging caused by immune dysfunction-mediated inflammation exists in patients with SSc. Hence, increased cellular senescence is elicited by the interactions among excessive oxidative stress, pro-inflammatory cytokines, and autoantibodies. In the present review, we will discuss in detail the molecular basis of chromosome instability, increased oxidative stress, and functional adaptation by deranged immunome, which are related to inflamm-aging in patients with SSc.

A review and roadmap of the skin, lung and gut microbiota in systemic sclerosis

As our understanding of the genetic underpinnings of SSc increases, questions regarding the environmental trigger(s) that induce and propagate SSc in the genetically predisposed individual emerge. The interplay between the environment, the immune system, and the microbial species that inhabit the patient's skin and gastrointestinal tract is a pathobiological frontier that is largely unexplored in SSc. The purpose of this review is to provide an overview of the methodologies, experimental study results and future roadmap for elucidating the relationship between the SSc host and his/her microbiome.

Immunomodulation by heavy metals as a contributing factor to inflammatory diseases and autoimmune reactions: Cadmium as an example

Cadmium (Cd) represents a unique hazard because of the long biological half-life in humans (20-30 years). This metal accumulates in organs causing a continuum of responses, with organ disease/failure as extreme outcome. Some of the cellular and molecular alterations in target tissues can be related to immune-modulating potential of Cd. This metal may cause adverse responses in which components of the immune system function as both mediators and effectors of Cd tissue toxicity, which, in combination with Cd-induced alterations in homeostatic reparative activities may contribute to tissue dysfunction. In this work, current knowledge concerning inflammatory/autoimmune disease manifestations found to be related with cadmium exposure are summarized. Along with epidemiological evidence, animal and in vitro data are presented, with focus on cellular and molecular immune mechanisms potentially relevant for the disease susceptibility, disease promotion, or facilitating development of pre-existing pathologies.

Current Concepts on the Pathogenesis of Systemic Sclerosis

From the clinical standpoint, systemic sclerosis (SSc) is characterized by skin and internal organ fibrosis, diffuse fibroproliferative vascular modifications, and autoimmunity. Clinical presentation and course are highly heterogenous and life expectancy variably affected mostly dependent on lung and heart involvement. SSc touches more women than men with differences in disease severity and environmental exposure. Pathogenetic events originate from altered homeostasis favored by genetic predisposition, environmental cues and a variety of endogenous and exogenous triggers. Epigenetic modifications modulate SSc pathogenesis which strikingly associate profound immune-inflammatory dysregulation, abnormal endothelial cell behavior, and cell trans-differentiation into myofibroblasts. SSc myofibroblasts show enhanced survival and enhanced extracellular matrix deposition presenting altered structure and altered physicochemical properties. Additional cell types of likely pathogenic importance are pericytes, platelets, and keratinocytes in conjunction with their relationship with vessel wall cells and fibroblasts. In SSc, the profibrotic milieu is favored by cell signaling initiated in the one hand by transforming growth factor-beta and related cytokines and in the other hand by innate and adaptive type 2 immune responses. Radical oxygen species and invariant receptors sensing danger participate to altered cell behavior. Conventional and SSc-specific T cell subsets modulate both fibroblasts as well as endothelial cell dysfunction. Beside autoantibodies directed against ubiquitous antigens important for enhanced clinical classification, antigen-specific agonistic autoantibodies may have a pathogenic role. Recent studies based on single-cell RNAseq and multi-omics approaches are revealing unforeseen heterogeneity in SSc cell differentiation and functional states. Advances in system biology applied to the wealth of data generated by unbiased screening are allowing to subgroup patients based on distinct pathogenic mechanisms. Deciphering heterogeneity in pathogenic mechanisms will pave the way to highly needed personalized therapeutic approaches.

Autoimmunity in 2019

Based on the PubMed data, we have been performing a yearly evaluation of the publications related to autoimmune diseases and immunology to ascertain the relative weight of the former in the scientific literature. It is particularly intriguing to observe that despite the numerous new avenues of immune-related mechanisms, such as cancer immunotherapy, the proportion of immunology manuscripts related to autoimmunity continues to increase and has been approaching 20% in 2019. As in the previous 13 years, we performed an arbitrary selection of the peer-reviewed articles published by the major dedicated Journals and discussed the common themes which continue to outnumber peculiarites in autoimmune diseases. The investigated areas included systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), psoriatic arthritis (PsA), autoantibodies (autoAbs), and common therapeutic avenues and novel pathogenic mechanisms for autoimmune conditions. Some examples include new pathogenetic evidence which is well represented by IL21 or P2X7 receptor (P2X7R) in SLE or the application of single-cell RNA sequencing (scRNA-seq), mass cytometry, bulk RNA sequencing (RNA-seq), and flow cytometry for the analysis of different cellular populations in RA. Cumulatively and of interest to the clinicians, a large number of findings continue to underline the importance of a strict relationship between basic and clinical science to define new pathogenetic and therapeutic developments. The therapeutic pipeline in autoimmunity continues to grow and maintain a constant flow of new molecules, as well illustrated in RA and PsA, and this is most certainly derived from the new basic evidence and the high-throughput tools applied to autoimmune diseases.

Scleroderma epidemiology update

PURPOSE OF REVIEW

Systemic sclerosis (scleroderma, SSc) is a rare multisystem autoimmune disease characterized by autoantibodies, vasculopathy, and fibrosis of the skin and internal organs. This review aims to provide an overview and summary of the recent epidemiological studies in systemic sclerosis.

RECENT FINDINGS

Global trends of scleroderma demonstrate greater prevalence of SSc in European, North, and South American patients compared with East Asian patients. However, the greatest prevalence (47 in 100 000), was found among the indigenous peoples in Canada. Phenotypical differences exist depending on the age of presentation with greater internal organ involvement and disease acceleration present in older patients. Sex differences include greater severity of disease expression, relative prevalence of diffuse cutaneous SSc, and organ involvement in males versus females. New studies conflict with previous data reporting greater proportion of pulmonary arterial hypertension in females. Furthermore, the effect of low median household income is demonstrated as a factor increasing risk of death in SSc patients.

SUMMARY

Understanding the epidemiological factors in SSc enables patient care through patient classification, prognostication, and monitoring. Future research may emphasize enrichment of SSc patients in randomized trials who are more likely to progress or be treatment responsive, focused screening, and personalized patient care through the creation and validation of new SSc criteria and subsets.

Chemical exposure-induced systemic fibrosing disorders: Novel insights into systemic sclerosis etiology and pathogenesis

Numerous drugs and chemical substances are capable of inducing exaggerated tissue fibrotic responses. The vast majority of these agents cause localized fibrotic tissue reactions or fibrosis confined to specific organs. Although much less frequent, chemically-induced systemic fibrotic disorders have been described, sometimes occurring as temporally confined outbreaks. These include the Toxic Oil Syndrome (TOS), the Eosinophilia-Myalgia Syndrome (EMS), and Nephrogenic Systemic Fibrosis (NSF). Although each of these disorders displays some unique characteristics, they all share crucial features with Systemic Sclerosis (SSc), the prototypic idiopathic systemic fibrotic disease, including vasculopathy, chronic inflammatory cell infiltration of affected tissues, and cutaneous and visceral tissue fibrosis. The study of the mechanisms and molecular alterations involved in the development of the chemically-induced systemic fibrotic disorders has provided valuable clues that may allow elucidation of SSc etiology and pathogenesis. Here, we review relevant aspects of the TOS, EMS, and NSF epidemic outbreaks of chemically-induced systemic fibrosing disorders that provide strong support to the hypothesis that SSc is caused by a toxic or biological agent that following its internalization by endothelial cells induces in genetically predisposed individuals a series of molecular alterations that result in the development of SSc clinical and pathological alterations.

Association between systemic sclerosis and risk of lung cancer: results from a pool of cohort studies and Mendelian randomization analysis

BACKGROUND

Population-based cohort studies have indicated that systemic sclerosis (SSc) may be associated with an increased risk of lung cancer. However, there are few studies that comprehensively investigate their correlation and the causal effect remains unknown.

METHODS

A systematic search of PubMed, Web of Science, Cochrane Library and Embase from the inception dates to December 1, 2019 was carried out. Meta-analysis was performed to calculate odds ratio (OR) and corresponding 95% confidence interval (CI) using random-effects models. Subgroup analyses were performed regarding gender. Two-sample Mendelian randomization (MR) was carried out with summary data from published genome-wide association studies of SSc (Neale Lab, 3871 individuals; UK Biobank, 463,315 individuals) and lung cancer (International Lung Cancer Consortium, 27,209 individuals; UK Biobank, 508,977 individuals). Study-specific estimates were summarized using inverse variance-weighted, weighted median, and MR-Egger method.

RESULTS

Through meta-analysis of 10 population-based cohort studies involving 12,218 patients, we observed a significantly increased risk of lung cancer among patients with SSc (OR 2.80, 95% CI 1.55-5.03). In accordance with subgroup analysis, male patients (OR 4.11, 95% CI 1.92-8.79) had a 1.5-fold higher lung cancer risk compared with female patients (OR 2.73, 95% CI 1.41-5.27). However, using a score of 11 SSc-related single nucleotide polymorphisms (p < 5*10^-8) as instrumental variables, the MR study did not support a causality between SSc and lung cancer (OR 1.001, 95% CI 0.929-1.100, p = 0.800). Specifically, subgroup MR analyses indicated that SSc was not associated with increased risks of non-small-cell lung cancer (OR 1.000, 95% CI 0.999-1.000, p = 0.974), including lung adenocarcinoma (OR 0.996, 95% CI 0.906-1.094, p = 0.927), squamous cell lung carcinoma (OR 1.034, 95% CI 0.937-1.140, p = 0.507), nor small-cell lung cancer (OR 1.000, 95% CI 0.999-1.000, p = 0.837).

CONCLUSIONS

This study indicated an increased risk of lung cancer among patients with SSc by meta-analysis, whereas the MR study did not support a causality between the two diseases. Further studies are warranted to investigate the factors underlying the attribution of SSc to lung cancer risk.

Was Paul Klee's scleroderma an occupational disease? A series of historical and clinical vignettes, part III

Paul Klee (1879-1940), one of the most influential artists of the 20th century, died at 60 years of age from complications of systemic sclerosis (scleroderma). The precipitating event(s) of Klee's scleroderma, as in most cases, will never be known. Among various potential factors, exposure to heavy metals, crystalline silica, and organic solvents-acting alone or in combination-can now be considered potential factors in the onset of Klee's disease. By altering and modulating epigenetic determinants in a genetically susceptible host, these and other environmental factors may have led to perturbations of self-tolerance and inflammation culminating in Klee's scleroderma.

Pathogenic Roles of Autoantibodies and Aberrant Epigenetic Regulation of Immune and Connective Tissue Cells in the Tissue Fibrosis of Patients with Systemic Sclerosis

Systemic sclerosis (SSc) is a multi-system autoimmune disease with tissue fibrosis prominent in the skin and lung. In this review, we briefly describe the autoimmune features (mainly autoantibody production and cytokine profiles) and the potential pathogenic contributors including genetic/epigenetic predisposition, and environmental factors. We look in detail at the cellular and molecular bases underlying tissue-fibrosis which include trans-differentiation of fibroblasts (FBs) to myofibroblasts (MFBs). We also state comprehensively the pro-inflammatory and pro-fibrotic cytokines relevant to MFB trans-differentiation, vasculopathy-associated autoantibodies, and fibrosis-regulating microRNAs in SSc. It is conceivable that tissue fibrosis is mainly mediated by an excessive production of TGF-β, the master regulator, from the skewed Th2 cells, macrophages, fibroblasts, myofibroblasts, and keratinocytes. After binding with TGF-β receptors on MFB, the downstream Wnt/β-catenin triggers canonical Smad 2/3 and non-canonical Smad 4 signaling pathways to transcribe collagen genes. Subsequently, excessive collagen fiber synthesis and accumulation as well as tissue fibrosis ensue. In the later part of this review, we discuss limited data relevant to the role of long non-coding RNAs (lncRNAs) in tissue-fibrosis in SSc. It is expected that these lncRNAs may become the useful biomarkers and therapeutic targets for SSc in the future. The prospective investigations in the development of novel epigenetic modifiers are also suggested.

Gender-related differences in systemic sclerosis

Systemic sclerosis (SSc) is a complex autoimmune connective tissue disease which is characterised by autoimmunity, widespread tissue fibrosis of the skin and internal organs, and vasculopathic alterations. SSc is more common in women but has a more severe expression of disease including internal organ-based complications and higher mortality in men. The extant literature shows that although important pathophysiological sex differences are present in SSc, behavioural differences (e.g. higher smoking rates in men) and occupational exposures may contribute to poorer outcomes in men with SSc. The higher death male death rate in the general population and greater prevalence of lung fibrosis are likely the key factors responsible for excess mortality found in men. Other important factors include (but are not limited to) a greater prevalence of the disease subset, delayed time to diagnosis, and higher disease activity in early disease in men. SSc carries a significant burden of disease-related morbidity; however, no qualitative studies to date have focussed on gender differences in SSc. The purpose of this review is to provide a comprehensive overview of gender differences in SSc including (but not limited to) epidemiology, pathophysiology, clinical expression of disease, mortality, SSc in transgender individuals, and psychosocial aspects of disease.

Interaction between food antigens and the immune system: Association with autoimmune disorders

It has been shown that environmental factors such as infections, chemicals, and diet play a major role in autoimmune diseases; however, relatively little attention has been given to food components as the most prevalent modifiers of these afflictions. This review summarizes the current body of knowledge related to different mechanisms and associations between food proteins/peptides and autoimmune disorders. The primary factor controlling food-related immune reactions is the oral tolerance mechanism. The failure of oral tolerance triggers immune reactivity against dietary antigens, which may initiate or exacerbate autoimmune disease when the food antigen shares homology with human tissue antigens. Because the conformational fit between food antigens and a host's self-determinants has been determined for only a few food proteins, we examined evidence related to the reaction of affinity-purified disease-specific antibody with different food antigens. We also studied the reaction of monoclonal or polyclonal tissue-specific antibodies with various food antigens and the reaction of food-specific antibodies with human tissue antigens. Examining the assembled information, we postulated that chemical modification of food proteins by different toxicants in food may result in immune reaction against modified food proteins that cross-react with tissue antigens, resulting in autoimmune reactivity. Because we are what our microbiome eats, food can change the gut commensals, and toxins can breach the gut barrier, penetrating into different organs where they can initiate autoimmune response. Conversely, there are also foods and supplements that help maintain oral tolerance and microbiome homeostasis. Understanding the potential link between specific food consumption and autoimmunity in humans may lay the foundation for further research about the proper diet in the prevention of autoimmune diseases.

Epigenetics of scleroderma: Integrating genetic, ethnic, age, and environmental effects

Scleroderma or systemic sclerosis is thought to result from the interplay between environmental or non-genetic factors in a genetically susceptible individual. Epigenetic modifications are influenced by genetic variation and environmental exposures, and change with chronological age and between populations. Despite progress in identifying genetic, epigenetic, and environmental risk factors, the underlying mechanism of systemic sclerosis remains unclear. Since epigenetics provides the regulatory mechanism linking genetic and non-genetic factors to gene expression, understanding the role of epigenetic regulation in systemic sclerosis will elucidate how these factors interact to cause systemic sclerosis. Among the cell types under tight epigenetic control and susceptible to epigenetic dysregulation, immune cells are critically involved in early pathogenic events in the progression of fibrosis and systemic sclerosis. This review starts by summarizing the changes in DNA methylation, histone modification, and non-coding RNAs associated with systemic sclerosis. It then discusses the role of genetic, ethnic, age, and environmental effects on epigenetic regulation, with a focus on immune system dysregulation. Given the potential of epigenome editing technologies for cell reprogramming and as a therapeutic approach for durable gene regulation, this review concludes with a prospect on epigenetic editing. Although epigenomics in systemic sclerosis is in its infancy, future studies will help elucidate the regulatory mechanisms underpinning systemic sclerosis and inform the design of targeted epigenetic therapies to control its dysregulation.

Mercury Is Taken Up Selectively by Cells Involved in Joint, Bone, and Connective Tissue Disorders

Background: The causes of most arthropathies, osteoarthritis, and connective tissue disorders remain unknown, but exposure to toxic metals could play a part in their pathogenesis. Human exposure to mercury is common, so to determine whether mercury could be affecting joints, bones, and connective tissues we used a histochemical method to determine the cellular uptake of mercury in mice. Whole neonatal mice were examined since this allowed histological assessment of mercury in joint, bone, and connective tissue cells. Materials and Methods: Pregnant mice were exposed to a non-toxic dose of 0.5 mg/m3 of mercury vapor for 4 h a day on gestational days 14-18. Neonates were sacrificed at postnatal day 1, fixed in formalin, and transverse blocks of the body were processed for paraffin embedding. Seven micrometer sections were stained for inorganic mercury using silver nitrate autometallography, either alone or combined with CD44 immunostaining to detect progenitor cells. Control neonates were not exposed to mercury during gestation. Results: Uptake of mercury was marked in synovial cells, articular chondrocytes, and periosteal and tracheal cartilage cells. Mercury was seen in fibroblasts in the dermis, aorta, esophagus and striated muscle, some of which were CD44-positive progenitor cells, and in the endothelial cells of small blood vessels. Mercury was also present in renal tubules and liver periportal cells. Conclusions: Mercury is taken up selectively by cells that are predominantly affected in rheumatoid arthritis and osteoarthritis. In addition, fibroblasts in several organs often involved in multisystem connective tissue disorders take up mercury. Mercury provokes the autoimmune, inflammatory, genetic, and epigenetic changes that have been described in a range of arthropathies and bone and connective tissue disorders. These findings support the hypothesis that mercury exposure could trigger some of these disorders, particularly in people with a genetic susceptibility to autoimmunity.

Emerging role of air pollution in autoimmune diseases

Autoimmune diseases (ADs) are a broad spectrum of disorders featured by the body's immune responses being directed against its own tissues, resulting in prolonged inflammation and subsequent tissue damage. Recently, the exposure to ambient air pollution has been implicated in the occurrence and development of ADs. Mechanisms linking air pollution exposures and ADs mainly include systemic inflammation, increased oxidative stress, epigenetic modifications induced by exposures and immune response caused by airway damage. The lung may be an autoimmunity initiation site in autoimmune diseases (ADs). Air pollutants can bind to the Aryl hydrocarbon receptor (AHR) to regulate Th17 and Treg cells. Oxidative stress and inducible bronchus associated lymphoid tissue caused by the pollutants can influence T, B cells, resulting in the production of proinflammatory cytokines. These cytokines stimulate B cell and dendritic cells, resulting in a lot of antibodies and self-reactive T lymphocytes. Moreover, air pollutants may induce epigenetic changes to contribute to ADs. In this review, we will concern the associations between air pollution and immune-inflammatory responses, as well as mechanisms linking air pollution exposure and autoimmunity. In addition, we focus on the potential roles of air pollution in major autoimmune diseases including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), multiple sclerosis (MS), and type 1 diabetes mellitus (T1DM).