Is exposure to environmental factors associated with a characteristic clinical and laboratory profile in systemic sclerosis? A retrospective analysis

Heterogeneity of determining disease severity, clinical course and outcomes in systemic sclerosis-associated interstitial lung disease: a systematic literature review

Objective The course of systemic sclerosis-associated interstitial lung disease (SSc-ILD) is highly variable and different from continuously progressive idiopathic pulmonary fibrosis (IPF). Most proposed definitions of progressive pulmonary fibrosis or SSc-ILD severity are based on the research data from patients with IPF and are not validated for patients with SSc-ILD. Our study aimed to gather the current evidence for severity, progression and outcomes of SSc-ILD.Methods A systematic literature review to search for definitions of severity, progression and outcomes recorded for SSc-ILD was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines in Medline, Embase, Web of Science and Cochrane Library up to 1 August 2023.Results A total of 9054 papers were reviewed and 342 were finally included. The most frequent tools used for the definition of SSc-ILD progression and severity were combined changes of carbon monoxide diffusing capacity (DLCO) and forced vital capacity (FVC), isolated FVC or DLCO changes, high-resolution CT (HRCT) extension and composite algorithms including pulmonary function test, clinical signs and HRCT data. Mortality was the most frequently reported long-term event, both from all causes or ILD related.Conclusions The studies presenting definitions of SSc-ILD 'progression', 'severity' and 'outcome' show a large heterogeneity. These results emphasise the need for developing a standardised, consensus definition of severe SSc-ILD, to link a disease specific definition of progression as a surrogate outcome for clinical trials and clinical practice.PROSPERO registration number CRD42022379254.Cite Now.

Structural and functional characteristics of the pulmonary hemomicrocirculatory bed in induced systemic sclerosis: an experimental study

The objective of this study was to investigate the effects of prolonged exposure to the oxidative agent NaClO on histopathological changes in the lung tissues of laboratory animals. Specifically, the study aimed to examine morphological changes in the pulmonary microcirculation and the level of vascular cell adhesion molecule-1 (VCAM-1) as a functional activity indicator of endothelial cells in animals with induced systemic sclerosis (SSc). A laboratory animal model was used to assess the impact of long-term exposure to NaClO on lung tissues. The animals were divided into three groups: the experimental group (25 rats) was exposed to NaClO, while the control group (20 rats) received an isotonic solution, and the intact group (15 animals) was without any exposure. The concentration of VCAM-1 in the serum of the animals was measured using an enzyme-linked immunosorbent assay. Histopathological analysis of lung tissue specimens was performed using both light and electron microscopy. The concentration of VCAM-1 in the serum of the animals in the experimental group was significantly higher than that of the control group (91.25 [85.63-143.75] vs 19.50 [13.53-22.20], p < 0.05). The histopathological analysis revealed significant abnormalities in the lung tissue specimens from the experimental group, including disruption in the structure of the hemocapillaries of the lungs, narrowing of the microvessel lumen, and perivascular infiltration by polymorphonuclear cells. The electron microscopic analysis showed several ultrastructural changes in the endotheliocytes of the hemocapillaries, including uneven expansion of the perinuclear space, swollen mitochondria, and fragmentation of the membranes of the granular endoplasmic reticulum. Additionally, the basement membrane of hemocapillaries showed uneven thickening with indistinct contours, and the peripheral parts of endotheliocytes were marked by numerous micropinocytotic vesicles and vacuoles. Erythrocyte aggregates and leukocyte adhesion were identified in the lumen of many hemocapillaries, while adhesion and aggregation of platelets were also observed in several hemocapillaries. Long-term exposure to NaClO can cause significant histopathological changes in lung tissues, including damage to the hemocapillaries and disruption in the structure of endotheliocytes.

Patients with inflammatory myopathies overlapping with systemic sclerosis: A Brazilian-Japanese bicentric study

Objectives

This study aims to describe and compare the demographic, clinical, and laboratory characteristics and follow-up of representative samples of patients with myopathies and systemic sclerosis overlap syndromes (Myo-SSc) from two tertiary centers.

Patients and methods

This is a cross-sectional and retrospective study conducted between January 2000 and December 2020. Fourty-five patients were analyzed with Myo-SSc (6 males, 39 females; mean age: 50.2±15.4 years; range, 45 to 65 years) from two tertiary centers (n=30 from Brazil and n=15 from Japan).

Results

The median follow-up was 98 (range, 37 to 168) months. Muscle impairment started simultaneously with the diagnosis of systemic sclerosis in 57.8% (26/45) of cases. Muscle involvement occurred before the onset of systemic sclerosis in 35.5% (16/45) of cases, and after in 6.7% (3/45). Polymyositis was observed in 55.6% (25/45) of cases, followed by dermatomyositis in 24.4% (11/45) and antisynthetase syndrome in 20.0% (9/45). Concerning systemic sclerosis, the diffuse and limited forms occurred in 64.4% (29/45) and 35.6% (16/45) of the cases, respectively. Comparing the subgroups, Myo or SSc onset was earlier in Brazilian patients, and they had a higher frequency of dysphagia (20/45, [66.7%]) and digital ulcers (27/45, [90%]), whereas Japanese patients had higher modified Rodnan skin scores (15 [9 to 23]) and prevalence of positive anti-centromere antibodies (4/15 [23.7%]). The current disease status and mortality were similar in both groups.

Conclusion

In the present study, Myo-SSc affected middle-aged women, and its manifestation spectrum varied according to geographic distribution.

Autoimmune pre-disease

Approximately 5% of the world-wide population is affected by autoimmune diseases. Overall, autoimmune diseases are still difficult to treat, impose a high burden on patients, and have a significant economic impact. Like other complex diseases, e.g., cancer, autoimmune diseases develop over several years. Decisive steps in the development of autoimmune diseases are (i) the development of autoantigen-specific lymphocytes and (often) autoantibodies and (ii) potentially clinical disease manifestation at a later stage. However, not all healthy individuals with autoantibodies develop disease manifestations. Identifying autoantibody-positive healthy individuals and monitoring and inhibiting their switch to inflammatory autoimmune disease conditions are currently in their infancy. The switch from harmless to inflammatory autoantigen-specific T and B-cell and autoantibody responses seems to be the hallmark for the decisive factor in inflammatory autoimmune disease conditions. Accordingly, biomarkers allowing us to predict this progression would have a significant impact. Several factors, such as genetics and the environment, especially diet, smoking, exposure to pollutants, infections, stress, and shift work, might influence the progression from harmless to inflammatory autoimmune conditions. To inspire research directed at defining and ultimately targeting autoimmune predisease, here, we review published evidence underlying the progression from health to autoimmune predisease and ultimately to clinically manifest inflammatory autoimmune disease, addressing the following 3 questions: (i) what is the current status, (ii) what is missing, (iii) and what are the future perspectives for defining and modulating autoimmune predisease.

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.

The Involvement of Smooth Muscle, Striated Muscle, and the Myocardium in Scleroderma: A Review

Systemic sclerosis (SSc) is a complex autoimmune disease characterized by heterogeneous changes involving numerous organs and systems. The currently available data indicate that muscle injury (both smooth and striated muscles) is widespread and leads to significant morbidity, either directly or indirectly. From the consequences of smooth muscle involvement in the tunica media of blood vessels or at the level of the digestive tract, to skeletal myopathy (which may be interpreted strictly in the context of SSc, or as an overlap with idiopathic inflammatory myopathies), muscular injury in scleroderma translates to a number of notable clinical manifestations. Heart involvement in SSc is heterogenous depending on the definition used in the various studies. The majority of SSc patients experience a silent form of cardiac disease. The present review summarizes certain important features of myocardial, as well as smooth and skeletal muscle involvement in SSc. Further research is needed to fully describe and understand the pathogenic pathways and the implications of muscle involvement in scleroderma.

Autoantibodies as Biomarker and Therapeutic Target in Systemic Sclerosis

Systemic sclerosis (SSc) is a rare connective tissue disorder characterized by immune dysregulation evoking the pathophysiological triad of inflammation, fibrosis and vasculopathy. In SSc, several alterations in the B-cell compartment have been described, leading to polyclonal B-cell hyperreactivity, hypergammaglobulinemia and autoantibody production. Autoreactive B cells and autoantibodies promote and maintain pathologic mechanisms. In addition, autoantibodies in SSc are important biomarkers for predicting clinical phenotype and disease progression. Autoreactive B cells and autoantibodies represent potentially promising targets for therapeutic approaches including B-cell-targeting therapies, as well as strategies for unselective and selective removal of autoantibodies. In this review, we present mechanisms of the innate immune system leading to the generation of autoantibodies, alterations of the B-cell compartment in SSc, autoantibodies as biomarkers and autoantibody-mediated pathologies in SSc as well as potential therapeutic approaches to target these.

A broad look into the future of systemic sclerosis

Systemic sclerosis (SSc) is a systemic autoimmune disease with the key features of inflammation, vasculopathy and fibrosis. This article focussed on emerging fields based on the authors’ current work and expertise. The authors provide a hierarchical structure into the studies of the pathogenesis of SSc starting with the contribution of environmental factors. Regulatory autoantibodies (abs) are discussed, which are parts of the human physiology and are specifically dysregulated in SSc. Abs against the angiotensin II receptor subtype 1 (AT1R) and the endothelin receptor type A (ETAR) are discussed in more detail. Extracellular vesicles are another novel player to possess disease processes. Fibroblasts are a key effector cell in SSc. Therefore, the current review will provide an overview about their plasticity in the phenotype and function. Promising nuclear receptors as key regulators of transcriptional programmes will be introduced as well as epigenetic modifications, which are pivotal to maintain the profibrotic fibroblast phenotype independent of external stimuli. Fibroblasts from SSc patients exhibit a specific signalling and reactivate developmental pathways and stem cell maintenance such as by employing hedgehog and WNT, which promote fibroblast-to-myofibroblast transition and extracellular matrix generation. Pharmacological interventions, although for other indications, are already in clinical use to address pathologic signalling.

Independent association between occupational exposure and decline of forced vital capacity in systemic sclerosis (SSc): a multicenter recruitment retrospective cohort study

BACKGROUND

Although male sex is associated with poor prognosis in Systemic Sclerosis (SSc), it is unclear whether this association is independent of confounding factors such as occupational exposure to toxicants.

RESEARCH QUESTION

What is the respective impact of sex and occupational exposure on SSc patients' characteristics with a focus on lung function decline?

STUDY DESIGN AND METHODS

Patients with SSc (n=210, 55 males) underwent standardized quantitative assessment of occupational exposure through a cumulative exposure score (CES) in a multicenter recruitment retrospective cohort. Association of the CES with patients' characteristics was assessed. Mixed linear, logistic and Cox regression models were used to identify predictors of time variation of forced vital capacity (FVC) and the hemoglobin-corrected transfer coefficient for carbon monoxide in the lung (DLCOc).

RESULTS

Male sex was strongly associated with occupational exposure (OR=10.3, p<.0001). The CES was inversely correlated (r= -.20) and independently associated with decline in FVC over time and with occurrence of FVC decline ≥10% from baseline (p<.05). By contrast, the CES was not associated with decline in DLCOc or DLCOc decline ≥15%. There was no independent association between sex and decline in FVC or DLCOc. The prevalence of interstitial lung disease was similar across sex or occupational exposure.

INTERPRETATION

Occupational exposure to toxicants appears to independently predict decline of FVC in SSc patients, regardless of sex. Assessment of occupational exposure may be useful for SSc prognostication.