Pathogenesis Of Systemic Sclerosis Research Articles

Innate Immunity in Systemic Sclerosis Fibrosis: Recent Advances.

Systemic sclerosis (SSc) is a heterogeneous autoimmune disease characterized by three interconnected hallmarks (i) vasculopathy, (ii) aberrant immune activation, and (iii) fibroblast dysfunction leading to extracellular matrix deposition and fibrosis. Blocking or reversing the fibrotic process associated with this devastating disease is still an unmet clinical need. Although various components of innate immunity, including macrophages and type I interferon, have long been implicated in SSc, the precise mechanisms that regulate the global innate immune contribution to SSc pathogenesis remain poorly understood. Recent studies have identified new innate immune players, such as pathogen-recognition receptors, platelet-derived danger-associated molecular patterns, innate lymphoid cells, and plasmacytoid dendritic cells in the pathophysiology of SSc, including vasculopathy and fibrosis. In this review, we describe the evidence demonstrating the importance of innate immune processes during SSc development with particular emphasis on their role in the initiation of pathology. We also discuss potential therapeutic options to modulate innate immune cells or signaling in SSc that are emerging from these recent advances.

International Investigative Dermatology 2018 Meeting: Promoting Global Skin Biology and Skin Disease Research

International Investigative Dermatology 2018 Meeting: Promoting Global Skin Biology and Skin Disease Research

Higher levels of serum interleukin-35 are associated with the severity of pulmonary fibrosis and Th2 responses in patients with systemic sclerosis.

The aim of the study is to investigate the levels of serum interleukin-35 (IL-35) before and after treatment and its relationship with clinical parameters as well as the frequency of different subsets of CD4+ T cells in patients with systemic sclerosis (SSc) to explore the role of IL-35 in the pathogenesis of SSc. The levels of serum IL-35, interferon-γ (IFN-γ), IL-4, IL-17A, and IL-10 in 49 patients with SSc and 50 age- and gender-matched healthy subjects were measured by enzyme-linked immunosorbent assay (ELISA). The percentages of peripheral blood Th1, Th2, Th17 cells and Tregs in 49 SSc patients and 20 healthy controls were characterized by flow cytometry. The relationship between the levels of serum IL-35 and the percentages of different subsets of CD4+ T cells, disease duration, the values of forced vital capacity (FVC), modified Rodnan skin scores (MRSS) or high-resolution computed tomography (HRCT) scores was analyzed in patients with SSc. The levels of serum IL-35 in SSc patients were significantly higher than that of healthy controls (P < 0.001), but significantly reduced after treatment for 3months (P = 0.001). The levels of serum IL-35 were positively correlated with the HRCT scores in SSc patients (P = 0.014) and with disease duration in patients with diffuse cutaneous SSc (P = 0.03), but negatively correlated with the FVC values in SSc patients (P = 0.034). In comparison with that in the healthy controls, significantly decreased percentages of Th1, but increased Th2 and Th17 cells were detected in patients, leading to reduced ratios of Th1/Th2 and increased ratios of Th17/Tregs (P < 0.001). The levels of serum IL-35 were positively correlated with IL-4 (P = 0.036) and tended to be positively associated with the frequency of Tregs in SSc patients (P = 0.054). Higher levels of serum IL-35 may be associated with the development of SSc and severity of pulmonary fibrosis in SSc patients.

Double-blind, Randomized, 8-week Placebo-controlled followed by a 16-week open label extension study, with the LPA1 receptor antagonist SAR100842 for Patients With Diffuse Cutaneous Systemic Sclerosis

BACKGROUND Preclinical studies suggest a role for lysophosphatidic acid (LPA) in the pathogenesis of systemic sclerosis (SSc). OBJECTIVES SAR100842, a potent selective oral antagonist of LPA1 receptor, was assessed for safety, biomarkers and clinical efficacy in patients with diffuse cutaneous SSc (dcSSc). METHODS An 8-week double-blind, randomized, placebo-controlled study followed by a 16-week open label extension with SAR100842 was performed in patients with early dcSSc and a baseline Rodnan skin score (mRSS) of at least 15. The primary endpoint was safety during the double-blind phase of the trial. Exploratory endpoints included the identification of a LPA-induced gene signature in patients 'skin. RESULTS 17 of 32 subjects were randomized to placebo and 15 to SAR100842; 30 patients participated in the extension study. The most frequent adverse events reported for SAR100842 during the blinded phase were headache, diarrhea, nausea and fall and the safety profile was acceptable during the extension part. At Week 8, mean reduction in mRSS was numerically greater in the SAR100842 compared to placebo (mean change [SD]: -3.57 [4.18] versus -2.76 [4.85]; difference [95% CI]: -1.2 [-4.37 to 2.02], p=0.46). A greater reduction of LPA related genes was observed in skin of SAR100842 group at Week 8, indicating LPA target engagement. CONCLUSION SAR100842, a selective orally available LPA receptor antagonist, was well tolerated in patients with dcSSc. MRSS improved during the study although not reaching significance, and additional gene signature analysis suggested target engagement. These results need to be confirmed in a larger controlled trial. This article is protected by copyright. All rights reserved.

Abrogation of transforming growth factor-β-induced tissue fibrosis in TBRIcaCol1a2Cre transgenic mice by the second generation tyrosine kinase inhibitor SKI-606 (Bosutinib).

Transforming growth factor-β (TGF-β) plays a crucial role in the pathogenesis of Systemic Sclerosis (SSc) and other fibrotic disorders. TGF-β-mediated c-Abl and Src kinase activation induces strong profibrotic cascade signaling. The purpose of this study was to test in vivo the antifibrotic activity of Bosutinib (SKI-606), a second generation c-Abl and Src kinase inhibitor, on TGF-β induced cutaneous and pulmonary fibrosis. For this purpose, we employed the TBRIcaCol1a2Cre transgenic mice expressing an inducible constitutively active TGF-β receptor 1 constitutively activated by Col1a promoter-mediated Cre recombinase. The mice were treated parenterally with 2.5, 5.0 or 10.0 mg/kg/day of Bosutinib for 42 days. Skin and lungs from control and Bosutinib-treated mice (n = 6 per group) were assessed by histopathology, measurement of tissue hydroxyproline content, PCR analysis of tissue fibrosis associated gene expression, and evidence of myofibroblast activation. Mice with constitutive TGF-β-1 signaling displayed severe cutaneous and pulmonary fibrosis. Bosutinib administration decreased collagen deposition and hydroxyproline content in the dermis and lungs in a dose-dependent manner. Bosutinib also reversed the marked increase in profibrotic and myofibroblast activation-associated gene expression. These results demonstrate that constitutive TGF-β-1-signaling-induced cutaneous and pulmonary fibrosis were abrogated in a dose-related manner following parenteral administration of the c-Abl and Src tyrosine kinase inhibitor, Bosutinib. These results indicate that Bosutinib may be a potential therapeutic agent for tissue fibrosis in SSc and other fibroproliferative disorders.

Integration of genome-wide transcriptome and DNA methylome uncovered aberrant methylation-regulated genes and pathways in the peripheral blood mononuclear cells of systemic sclerosis

Abstract Objectives To delineate the interaction network between gene transcription and DNA methylation in PBMC of systemic sclerosis (SSc) patients and to identify methylation-regulated genes which are involved in the pathogenesis of SSc. Methods Genome-wide transcriptome and DNA methylome were profiled on PBMC from 30 SSc patients and 30 matched normal controls (NC). Differential expressed genes (DEGs) and differential methylated positions (DMPs) were integratively analyzed to identify methylation-regulated genes and associated molecular pathways. Results Transcriptome profiling distinguished 453 DEGs in SSc. Global DNA methylation analysis identified 925 DMPs located on 618 genes. Integration of DEGs and DMPs revealed 20 DEGs containing inversely associated DMPs. These 20 potential methylation-regulated DEGs (MeDEGs), including 12 up-regulated genes (ELANE, CTSG, LTBR, C3AR1, CSTA, SPI1, ODF3B, SAMD4A, PLAUR, NFE2, ZYX and CTSZ) and 8 down-regulated genes (RUNX3, PRF1, PRKCH, PAG1, RASSF5, FYN, CXCR6 and F2R), are predominantly involved in the migration, proliferation, activation and inflammation of immune cells. Unsupervised cluster analysis of the top MeDEGs distinguished SSc from NC with 90% sensitivity and 87% specificity. 4 MeDEGs, F2R, FYN, PAG1 and PRKCH, exhibited significantly progressive decrease in SSc with interstitial lung disease (ILD) compared with SSc without ILD. Conclusion By integration of genome-wide transcriptome and DNA methylome, we identified differential expressed genes associated with aberrant DNA methylation in the PBMC of SSc. The epigenetically dysregulated genes may lead to the abnormal activation of immune regulatory pathways which may contribute to the pathogenesis of SSc.

Deregulated PSGL-1 Expression in B Cells and Dendritic Cells May Be Implicated in Human Systemic Sclerosis Development.

Systemic sclerosis (SSc) is an autoimmune disorder with high morbidity and mortality, is difficult to diagnose early, and has no curative treatment. PSGL-1 is a leukocyte receptor whose deficiency in mice promotes an SSc-like disease. ADAM8, a metalloprotease that cleaves PSGL-1, is implicated in inflammatory processes. Our goal was to evaluate whether PSGL-1 and ADAM8 contribute to the pathogenesis of human SSc. We found that patients with SSc presented increased PSGL-1 expression on monocytes, dendritic cells, and T cells and decreased expression of PSGL-1 on B cells. PSGL-1 on monocytes from SSc patients failed to induce Syk phosphorylation or IL-10 production after interaction with P-selectin. Up to 60% of the IL-10-producing B cells expressed PSGL-1, pointing to a regulatory role for PSGL-1 in B cells, and PSGL-1+ B cells from SSc patients had decreased IL-10 production. ADAM8 expression was increased on antigen-presenting cells and T lymphocytes of SSc patients. Patients treated with calcium antagonists had lower levels of ADAM8 on APCs and T lymphocytes. Multivariate analysis indicated that the high percentage of ADAM8-expressing plasmacytoid dendritic cells discriminated patients from healthy donors. High PSGL-1 expression on dendritic cells was associated with the presence of interstitial lung disease.

060 The cytokine production of autoantigen-reactive B cells associates with pathogenesis in systemic sclerosis

060 The cytokine production of autoantigen-reactive B cells associates with pathogenesis in systemic sclerosis

Oxidative stress in the pathogenesis of systemic scleroderma: An overview.

Systemic sclerosis (SSc) is a rare disorder of the connective tissue characterized by fibrosis of the skin, skeletal muscles and visceral organs. Additional manifestations include activation of the immune system and vascular injury. SSc causes disability and death as the result of end‐stage organ failure. Two clinical subsets of the SSc are accepted: limited cutaneous SSc (lc‐SSc) and diffuse cutaneous SSc (dc‐SSc). At present, the aetiology and pathogenesis of SSc remain obscure, and consequently, disease outcome is unpredictable. Numerous studies suggest that reactive oxidizing species (ROS) play an important role in the pathogenesis of scleroderma. Over the years, several reports have supported this hypothesis for both lc‐SSc and dc‐SSc, although the specific role of oxidative stress in the pathogenesis of vascular injury and fibrosis remains to be clarified. The aim of the present review was to report and comment the recent findings regarding the involvement and role of oxidative stress in SSc pathogenesis. Biomarkers proving the link between ROS and the main pathological features of SSc have been summarized.

RGC32 Promotes Bleomycin-Induced Systemic Sclerosis in a Murine Disease Model by Modulating Classically Activated Macrophage Function.

Systemic sclerosis (SSc) is a multisystem autoimmune disorder that is characterized by inflammation and fibrosis in the skin and internal organs. Previous studies indicate that inflammatory cells and cytokines play essential roles in the pathogenesis of SSc; however, the mechanisms that underlie the inflammation-driven development of SSc are not fully understood. In this study, we show that response gene to complement 32 (RGC32) is abundantly expressed in mouse macrophages in the early stage of bleomycin-induced SSc. Importantly, RGC32 is required to induce the inflammatory response during the onset of SSc, because RGC32 deficiency in mice significantly ameliorates skin and lung sclerosis and inhibits the expression of inflammatory mediators inducible NO synthase (iNOS) and IL-1β in macrophages. RGC32 appears to be a novel regulator for the differentiation of classically activated macrophages (M1 macrophages). IFN-γ and LPS stimulation induces RGC32 expression in primary peritoneal macrophages and bone marrow-derived macrophages. RGC32 deficiency impairs the polarization of M1 macrophages and attenuates iNOS and IL-1β production. Mechanistically, RGC32 interacts with NF-κB proteins and promotes iNOS and IL-1β expression by binding to their promoters. Collectively, our data reveal that RGC32 promotes the onset of SSc by regulating the inflammatory response of M1 macrophages, and it may serve as a promising therapeutic target for treating SSc.

Asiatic acid prevents the development of interstitial lung disease in a hypochlorous acid-induced mouse model of scleroderma.

Interstitial lung disease is the most common complication of systemic sclerosis (SSc) and is associated with a high rate of mortality. Due to the complex pathogenesis of SSc, the therapies currently available remain limited. In the present study, the effect of asiatic acid (AA) on SSc-associated pulmonary fibrosis (PF) and its association with the transforming growth factor-β1 (TGF-β1)/Smad2/3 signaling pathway were evaluated. A hypochlorous acid (HOCl)-induced model of SSc was used to evaluate the therapeutic effect of AA on PF in SSc, where AA was administered to SSc mice by gavage. PF was alleviated in the AA-treated SSc mice groups when examined under light microscopy. In addition, there was a decrease in histopathological progression and collagen in the lungs. AA significantly reduced expression of type I collagen in the lungs of mice with SSc. It also significantly suppressed α-smooth muscle actin expression, which attenuated the conversion of fibroblasts into muscle fibroblasts. These AA-associated antifibrosis and anti-immune effects were mediated through the significant downregulation of advanced oxidation protein product, E-selectin, and anti-DNA topoisomerase-1 autoantibody levels in the serum. Furthermore, the expression levels of TGF-β1 and the phosphorylated-Smad2/3/Smad2/3 ratios in AA-treated SSc mice were similar to the control. The presence of pulmonary inflammation and fibrosis was confirmed in the HOCl-induced SSc mice and the results demonstrated that selective inhibition of reactive oxygen species prevented PF. By focusing on the classical TGF-β1/Smad2/3 signaling pathway, a mechanism of action of AA was identified to be associated with the inhibition of Smad2/3 activation through negative regulation of Smad2/3 phosphorylation.

Different profile of cytokine production in patients with systemic sclerosis and association with clinical manifestations

Immune dysregulation is a central process in the pathogenesis of systemic sclerosis (SSc). Cytokines produced by lymphocytes and monocytes are important mediators and induce tissue damage, recruit additional inflammatory cells, and promote extracellular matrix production and fibrosis. In the present research, we aimed to study the associations between levels of cytokines in serum and culture supernatants from peripheral blood mononuclear cells (PBMCs) and clinical manifestations in SSc patients. Serum samples were obtained from 56 SSc patients and 56 unrelated age- and gender-matched healthy individuals. Resting and anti-CD3/CD28–stimulated PBMC cultures were obtained from 19 SSc patients and 8 healthy controls. IL-2, IL-4, IL-6, IL-10, IL-17A, TNF, and IFN-γ levels were measured by ELISA or CBA. Serum cytokines, except IL-17A, were below the kit detection limit in most of the patients and controls. In unstimulated PBMC, the production of TNF(p = 0.004), IL-10(p = .048), IL-2(p < 0.001), and IL-6 (p = 0.01) was higher in SSc patients than in healthy controls. After anti-CD3/CD28 stimulation, scleroderma PBMCs had lower concentrations of TNF(p = 0.009), IL-10(p = .018), and IL-2(p = .002) than HC. In unstimulated PBMC, IL-2 concentration was higher in patients with esophageal dysmotility (p = 0.04), and IL-10 levels had a positive correlation with modified Rodnan score (p = 0.03). After anti-CD3/CD28 stimulation, higher levels of IL-2 and IL-4 were observed in SSc patients with lung fibrosis (p = 0.01 and 0.006, respectively), and higher levels of IL-10 (p = 0.04) and IL-4 (p = 0.04) in patients with digital ulcers. In conclusion, SSc patients have a different profile of cytokine production and this was associated with clinical manifestations.

TNFSF14 (LIGHT) Exhibits Inflammatory Activities in Lung Fibroblasts Complementary to IL-13 and TGF-β.

The cytokine TNFSF14 [homologous to Lymphotoxin, exhibits Inducible expression and competes with HSV Glycoprotein D for binding to HVEM, a receptor expressed on T lymphocytes (LIGHT)] has been shown in mouse models to be important for development of lung tissue remodeling that is characteristic of asthma, idiopathic pulmonary fibrosis (IPF), and systemic sclerosis (SSc). However, its cellular targets are not fully delineated. In the present report, we show that LTβR and HVEM, the receptors for LIGHT, are constitutively expressed in primary human lung fibroblasts (HLFs). We asked whether LIGHT could promote inflammatory and remodeling-relevant activity in HLFs and how this was similar to, or distinct from, IL-13 or TGF-β, two cytokines strongly implicated in the pathogenesis of asthma, IPF, and SSc. Accumulation of myofibroblasts expressing alpha smooth muscle actin is a feature of lung inflammatory diseases. LIGHT promoted cell cycle progression and proliferation of HLFs, but not alpha smooth muscle actin expression. In contrast, TGF-β upregulated alpha smooth muscle actin but did not drive their proliferation. LIGHT also increased the gene or protein expression of a number of proinflammatory mediators, including ICAM-1 and VCAM-1, IL-6 and GM-CSF, the chemokines CCL5 and 20, and CXCL5, 11, and 12, and lung remodeling-associated proteinases MMP-9 and ADAM8. These were dependent on LTβR but not HVEM. LIGHT displayed overlapping and synergistic activities with IL-13 for a number of the activities, but LIGHT additionally enhanced the gene expression of several molecules, including the innate cytokines IL-33 and TSLP, which were not upregulated by IL-13. Our results highlight the varied and pleiotropic effects of LIGHT in HLFs. LIGHT might then be a therapeutic target for modulation of inflammation and remodeling associated with asthma and other similar diseases of the lung that involve fibroblasts.

Possible role of adipocytokines in systemic sclerosis-associated small pericardial effusion.

Pericardial effusion is a common manifestation of systemic sclerosis, but its pathogenesis has been poorly investigated. Adipokines and interleukins may play a role in the pathophysiology of pericardial effusion. This study aimed at evaluating serum levels of adipokines and interleukins in systemic sclerosis patients with and without pericardial effusion. A total of 87 systemic sclerosis patients (age 52.6 ± 14 years; disease duration 8.2 ± 6.7 years) were recruited in this study. Demographics, body mass index, and clinical characteristics were recorded in each patient. Pericardial effusion was considered pathologic when ≥50 mL was detected by echocardiography. Serum levels of adiponectin, leptin, resistin, visfatin, tumor necrosis factor-α, interferon-γ, interlueukin-2, interlueukin-10, and interlueukin-17 were measured using Multiplex Immunoassay (Bioplex 200 System). In all, 11 (13%) systemic sclerosis patients had pericardial effusion. Systemic sclerosis patients with and without pericardial effusion did not differ in age, sex, and body mass index. Systemic sclerosis patients with pericardial effusion had significantly higher levels of visfatin (median/interquartile range: 1546 pg/mL (interquartile range: 8590) vs 388 pg/mL (interquartile range: 103), p = 0.03) and interlueukin-17 (1.33 pg/mL (interquartile range: 3.5) vs 0.05 pg/mL (interquartile range: 0.56), p = 0.04), but lower levels of adiponectin (2,845,000 pg/mL (interquartile range: 4,132,900) vs 5,272,100 pg/mL (interquartile range 8,243,600), p = 0.02) than patients without pericardial effusion. Interstitial lung disease, pulmonary arterial hypertension, and "limited" or "diffuse" cutaneous subset did not correlate to adipokines or interleukin levels. Visfatin and adiponectin may play an important role in the pathogenesis of systemic sclerosis-related pericardial effusion. Further longitudinal studies are needed to unravel a possible role of these molecules as biomarkers of pericardial effusion in systemic sclerosis patients.

Blockade of TGF-\u03b2/Smad signaling by the small compound HPH-15 ameliorates experimental skin fibrosis

BackgroundTransforming growth factor-β (TGF-β)/Smad signaling is well known to play a critical role in the pathogenesis of systemic sclerosis (SSc). We previously developed an artificial molecule, the histidine-pyridine-histidine ligand derivative HPH-15, which may have an antifibrotic effect. The purpose of the present study was to clarify the effects of this drug in human skin fibroblasts and in a preclinical model of SSc.MethodsThe effects of HPH-15 on expression of extracellular matrix components and TGF-β signaling in human dermal fibroblasts were analyzed. The antifibrotic properties of HPH-15 and its mechanisms were also examined in a bleomycin-induced skin fibrosis mouse model.ResultsHPH-15 suppressed the TGF-β-induced phosphorylation of Smad3 and inhibited the expression of collagen I, fibronectin 1, connective tissue growth factor, and α-smooth muscle actin induced by TGF-β in cultured human skin fibroblasts. In the bleomycin-induced skin fibrosis model, oral administration of HPH-15 protected against the development of skin fibrosis and ameliorated established skin fibrosis. Additionally, HPH-15 suppressed the phosphorylation of Smad3 in various cells, including macrophages in the bleomycin-injected skin. Further, in the treated mice, dermal infiltration of proinflammatory macrophages (CD11b+Ly6Chi) and M2 profibrotic macrophages (CD11b+CD204+ or CD11b+CD206+) was significantly decreased during the early and late stages, respectively. HPH-15 treatment resulted in decreased messenger RNA (mRNA) expression of the M2 macrophage markers arginase 1 and Ym-1 in the skin, whereas it inversely augmented expression of Friend leukemia integration 1 and Krüppel-like factor 5 mRNAs, the transcription factors that repress collagen synthesis. No apparent adverse effects of HPH-15 were found during the treatment.ConclusionsHPH-15 may inhibit skin fibrosis by inhibiting the phosphorylation of Smad3 in dermal fibroblasts and possibly in macrophages. Our results demonstrate several positive qualities of HPH-15, including oral bioavailability, a good safety profile, and therapeutic effectiveness. Thus, this TGF-β/Smad inhibitor is a potential candidate therapeutic for SSc clinical trials.

Gene Profiling in Patients with Systemic Sclerosis Reveals the Presence of Oncogenic Gene Signatures.

Systemic sclerosis (SSc) is a rare connective tissue disease characterized by three pathogenetic hallmarks: vasculopathy, dysregulation of the immune system, and fibrosis. A particular feature of SSc is the increased frequency of some types of malignancies, namely breast, lung, and hematological malignancies. Moreover, SSc may also be a paraneoplastic disease, again indicating a strong link between cancer and scleroderma. The reason of this association is still unknown; therefore, we aimed at investigating whether particular genetic or epigenetic factors may play a role in promoting cancer development in patients with SSc and whether some features are shared by the two conditions. We therefore performed a gene expression profiling of peripheral blood mononuclear cells (PBMCs) derived from patients with limited and diffuse SSc, showing that the various classes of genes potentially linked to the pathogenesis of SSc (such as apoptosis, endothelial cell activation, extracellular matrix remodeling, immune response, and inflammation) include genes that directly participate in the development of malignancies or that are involved in pathways known to be associated with carcinogenesis. The transcriptional analysis was then complemented by a complex network analysis of modulated genes which further confirmed the presence of signaling pathways associated with carcinogenesis. Since epigenetic mechanisms, such as microRNAs (miRNAs), are believed to play a central role in the pathogenesis of SSc, we also evaluated whether specific cancer-related miRNAs could be deregulated in the serum of SSc patients. We focused our attention on miRNAs already found upregulated in SSc such as miR-21-5p, miR-92a-3p, and on miR-155-5p, miR 126-3p and miR-16-5p known to be deregulated in malignancies associated to SSc, i.e., breast, lung, and hematological malignancies. miR-21-5p, miR-92a-3p, miR-155-5p, and miR-16-5p expression was significantly higher in SSc sera compared to healthy controls. Our findings indicate the presence of modulated genes and miRNAs that can play a predisposing role in the development of malignancies in SSc and are important for a better risk stratification of patients and for the identification of a better individualized precision medicine strategy.

Genetic predictors of systemic sclerosis-associated interstitial lung disease: a review of recent literature.

The interplay between genetic and environmental factors is likely involved in the pathogenesis of systemic sclerosis (SSc). Interstitial lung disease associated in the context of SSc (SSc-ILD) is associated with significant morbidity, and is the leading cause of death in SSc. The spectrum of SSc-ILD severity is wide, ranging from patients with only limited and inherently stable pulmonary involvement, to those with extensive and progressive pulmonary fibrosis. In order to provide accurate prognostic information for patients, and to initiate appropriate monitoring and treatment regimens, the ability to identify patients at risk of developing severe ILD early in the disease course is crucial. Identification of genetic variants involved in disease pathogenesis can not only potentially provide diagnostic/prognostic markers, but can also highlight dysregulated molecular pathways for therapeutic targeting. A number of genetic associations have been established for susceptibility to SSc, but far fewer studies have investigated genetic susceptibility to SSc-ILD specifically. In this review we present a summary of the studies assessing genetic associations with SSc-ILD.

High prevalence of occupational exposure to solvents or silica in male systemic sclerosis patients: a Belgian cohort analysis.

Increasing evidence supports a relation of some occupational exposures to systemic sclerosis pathogenesis. We aimed to evaluate occupational exposure and clinical characteristics in male patients with systemic sclerosis followed in two Belgian academic hospitals. One hundred and three male patients, included in the Belgian Systemic Sclerosis Cohort, were identified. An expert in occupational medicine reviewed the occupational history and allocated the patients to one of the following groups: probable exposure to crystalline silica, probable exposure to solvents, probable exposure to other toxins, or no suspected occupational exposure. Clinical characteristics were extracted from the Belgian Systemic Sclerosis Cohort database. Sufficient data were available for 96/103 patients. Most of these male patients (70/96, 72.9%) had a history of occupational exposure, 55 patients were likely exposed to crystalline silica, 11 patients to solvents, 2 patients to both silica and solvents, and 2 patients to asbestos. Only 26 patients had no suspected occupational exposure (27.1%). We noticed a significant difference in smoking status between exposed and non-exposed patients, with the highest percentage of ever smokers in the group with solvent exposure (p = 0.011). We found no significant differences in disease phenotype between exposed and non-exposed patients. However, we noted a trend to a higher prevalence of anti-Scl70 antibodies, cardiac dysfunction, and higher disease activity score in patients with occupational exposure. We observed a strikingly high prevalence of occupational exposure to both silica and solvents in male systemic sclerosis patients. Occupational exposure to silica or solvents is highly prevalent in male systemic sclerosis patients.

Poly(ADP-ribose) polymerase-1 regulates fibroblast activation in systemic sclerosis

ObjectivesThe enzyme poly(ADP-ribose) polymerase-1 (PARP-1) transfers negatively charged ADP-ribose units to target proteins. This modification can have pronounced regulatory effects on target proteins. Recent studies showed that PARP-1 can poly(ADP-ribosyl)ate...

Soluble CD163 as a Potential Biomarker in Systemic Sclerosis.

Objective To evaluate the performance of serum and urinary sCD163 concentrations as possible biomarker in systemic sclerosis (SSc). Methods Urine and serum samples were obtained from SSc patients and age- and sex-matched controls. Serum and urinary sCD163 concentrations were measured by commercially available ELISA kit. SSc patients were assessed following international guidelines. Cross-sectional analyses were performed. Results Two hundred and three SSc patients were included. The control group consisted of 47 age- and sex-matched patients having noninflammatory diseases, mainly osteoporosis. Serum sCD163 levels were significantly higher in SSc patients compared with controls (mean ± SD: 529 ± 251 versus 385 ± 153 ng/mL; p < 0.001). Urinary sCD163 concentrations were higher in SSc patients than controls, but this did not reach significance (236 ± 498 versus 176 ± 173 ng/mg uCr; p = 0.580). The sCD163 concentrations were not associated with clinical, laboratory, and instrumental characteristics of SSc patients. Conclusion To our knowledge, this is the first evaluation of both serum and urinary sCD163 levels in SSc. Our results show a significant difference for sera values that should be prioritized for further studies as compared to urinary measurements. Our results further support that the M2 macrophages/CD163 signaling system may play a role in the pathogenesis of SSc, although we could not identify a subset of SSc patients with higher concentrations.