Recent advances in understanding the pathogenesis of scleroderma-interstitial lung disease

Roles of TRIM21/Ro52 in connective tissue disease-associated interstitial lung diseases

Multiple factors contribute to the development of connective tissue diseases (CTD), often alongside a range of interstitial lung diseases (ILD), including Sjögren's syndrome-associated ILD, systemic sclerosis-associated ILD, systemic lupus erythematosus-associated ILD, idiopathic inflammatory myositis-associated ILD. TRIM21(or Ro52), an E3 ubiquitin ligase, plays a vital role in managing innate and adaptive immunity, and maintaining cellular homeostasis, and is a focal target for autoantibodies in various rheumatic autoimmune diseases. However, the effectiveness of anti-TRIM21 antibodies in diagnosing CTD remains a matter of debate because of their non-specific nature. Recent studies indicate that TRIM21 and its autoantibody are involved in the pathogenesis of CTD-ILD and play an important role in diagnosis and prognosis. In this review, we focus on the contribution of TRIM21 in the pathogenesis of CTD-ILD, as well as the potential diagnostic value of its autoantibodies in different types of CTD-ILD for disease progression and potential as a novel therapeutic target.

Therapeutic Approaches for the Treatment of Interstitial Lung Disease: An Exploratory Review on Molecular Mechanisms

BACKGROUND

Interstitial Lung Diseases (ILDs) are characterized by shortness of breath caused by alveolar wall inflammation and/or fibrosis.

OBJECTIVE

Our review aims to study the depth of various variants of ILD, diagnostic procedures, pathophysiology, molecular dysfunction and regulation, subject and objective assessment techniques, pharmacological intervention, exercise training and various modes of delivery for rehabilitation.

METHOD

Articles are reviewed from PubMed and Scopus and search engines.

RESULTS

ILD is a rapidly progressing disease with a high mortality rate. Each variant has its own set of causal agents and expression patterns. Patients often find it challenging to self-manage due to persistent symptoms and a rapid rate of worsening. The present review elaborated on the pathophysiology, risk factors, molecular mechanisms, diagnostics, and therapeutic approaches for ILD will guide future requirements in the quest for innovative and tailored ILD therapies at the molecular and cellular levels.

CONCLUSION

The review highlights the rationale for conventional and novel therapeutic approaches for better management of ILD.

Characteristics and risk factors of mortality in patients with systemic sclerosis-associated interstitial lung disease

BACKGROUND

Systemic sclerosis (SSc) is a heterogeneous autoimmune disease characterized by dysregulation of fibroblast function, which often involves the lungs. Interstitial lung disease (ILD) associated with SSc (SSc-ILD) is a major cause of death among patients with SSc. Our study aimed to identify risk factors for mortality and compare the clinical characteristics of patients with SSc-ILD.

PATIENTS AND METHODS

Patients were retrospectively enrolled between 2010 and 2018 in a tertiary hospital in Korea. Patients with SSc-ILD were classified depending on the first pulmonary function test or radiologic findings: extensive (n = 46, >20% disease extent on computed tomography (CT) or forced vital capacity [FVC] < 70% in indeterminate cases) and limited (n = 60, <20% disease extent on CT or FVC ≥70% in indeterminate cases).

RESULTS

Patients in the extensive group were younger (mean age ± SD 49.3 ± 11.5) than those in the limited group (53.9 ± 12.5, p = .067) at diagnosis. The extensive group showed frequent pulmonary hypertension (43.5% vs. 16.7%, p = .009) and higher erythrocyte sedimentation rate (61.3 ± 33.7 vs. 42.1 ± 26.0, p = .003) and mortality (32.6%, mean duration of follow-up, 100.0 ± 44.7 months vs. 10.0%, 86.0 ± 53.4 months, p = .011). ILD was detected within five years from the first visit (median years 3.5 (1.0, 6.0) vs. 4.5 (0.6, 9.0), survivors vs. non-survivors), and mortality occurred in 19.8% of all patients during a 15-year follow-up. Older age, lower FVC, and initial disease stage (limited or extensive) were associated with mortality, but FVC decline was similar in the limited and extensive groups, such as 15-20% in the first year and 8-10% in the next year, regardless of the initial extent of the disease.

CONCLUSIONS

Approximately 10% of patients with SSc-ILD in the limited and extensive group showed progression. ILD was detected at a median of less than five years from the first visit; therefore, it is necessary to carefully monitor patients' symptoms and signs from an early stage. Long-term surveillance is also required.Key messagesPatients with systemic sclerosis-interstitial lung disease manifested a heterogeneous disease course.Approximately 10% of the patients in the limited group showed progression, which was similar to the proportion of patients in the extensive group.Interstitial lung disease was detected at a median of less than five years from the first visit.

Recent Advances in Cell-Based In Vitro Models to Recreate Human Intestinal Inflammation

Inflammatory bowel disease causes a major burden to patients and healthcare systems, raising the need to develop effective therapies. Technological advances in cell culture, allied with ethical issues, have propelled in vitro models as essential tools to study disease aetiology, its progression, and possible therapies. Several cell-based in vitro models of intestinal inflammation have been used, varying in their complexity and methodology to induce inflammation. Immortalized cell lines are extensively used due to their long-term survival, in contrast to primary cultures that are short-lived but patient-specific. Recently, organoids and organ-chips have demonstrated great potential by being physiologically more relevant. This review aims to shed light on the intricate nature of intestinal inflammation and cover recent works that report cell-based in vitro models of human intestinal inflammation, encompassing diverse approaches and outcomes.

Biomarkers in the Pathogenesis, Diagnosis, and Treatment of Systemic Sclerosis

Systemic sclerosis (SSc) is a complex autoimmune disease characterized by vascular damage, vasoinstability, and decreased perfusion with ischemia, inflammation, and exuberant fibrosis of the skin and internal organs. Biomarkers are analytic indicators of the biological and disease processes within an individual that can be accurately and reproducibly measured. The field of biomarkers in SSc is complex as recent studies have implicated at least 240 pathways and dysregulated proteins in SSc pathogenesis. Anti-nuclear antibodies (ANA) are classical biomarkers with well-described clinical classifications and are present in more than 90% of SSc patients and include anti-centromere, anti-Th/To, anti-RNA polymerase III, and anti-topoisomerase I antibodies. Transforming growth factor-β (TGF-β) is central to the fibrotic process of SSc and is intimately intertwined with other biomarkers. Tyrosine kinases, interferon-1 signaling, IL-6 signaling, endogenous thrombin, peroxisome proliferator-activated receptors (PPARs), lysophosphatidic acid receptors, and amino acid metabolites are new biomarkers with the potential for developing new therapeutic agents. Other biomarkers implicated in SSc-ILD include signal transducer and activator of transcription 4 (STAT4), CD226 (DNAX accessory molecule 1), interferon regulatory factor 5 (IRF5), interleukin-1 receptor-associated kinase-1 (IRAK1), connective tissue growth factor (CTGF), pyrin domain containing 1 (NLRP1), T-cell surface glycoprotein zeta chain (CD3ζ) or CD247, the NLR family, SP-D (surfactant protein), KL-6, leucine-rich α2-glycoprotein-1 (LRG1), CCL19, genetic factors including DRB1 alleles, the interleukins (IL-1, IL-4, IL-6, IL-8, IL-10 IL-13, IL-16, IL-17, IL-18, IL-22, IL-32, and IL-35), the chemokines CCL (2,3,5,13,20,21,23), CXC (8,9,10,11,16), CX3CL1 (fractalkine), and GDF15. Adiponectin (an indicator of PPAR activation) and maresin 1 are reduced in SSc patients. A new trend has been the use of biomarker panels with combined complex multifactor analysis, machine learning, and artificial intelligence to determine disease activity and response to therapy. The present review is an update of the various biomarker molecules, pathways, and receptors involved in the pathology of SSc.

Metabolic fingerprinting of systemic sclerosis: a systematic review

Introduction: Systemic sclerosis (SSc) is a chronic autoimmune disease, marked by an unpredictable course, high morbidity, and increased mortality risk that occurs especially in the diffuse and rapidly progressive forms of the disease, characterized by fibrosis of the skin and internal organs and endothelial dysfunction. Recent studies suggest that the identification of altered metabolic pathways may play a key role in understanding the pathophysiology of the disease. Therefore, metabolomics might be pivotal in a better understanding of these pathogenic mechanisms. Methods: Through a systematic review of the literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Guidelines (PRISMA), searches were done in the PubMed, EMBASE, Web of Science, and Scopus databases from 2000 to September 2022. Three researchers independently reviewed the literature and extracted the data based on predefined inclusion and exclusion criteria. Results: Of the screened studies, 26 fulfilled the inclusion criteria. A total of 151 metabolites were differentially distributed between SSc patients and healthy controls (HC). The main deregulated metabolites were those derived from amino acids, specifically homocysteine (Hcy), proline, alpha-N-phenylacetyl-L-glutamine, glutamine, asymmetric dimethylarginine (ADMA), citrulline and ornithine, kynurenine (Kyn), and tryptophan (Trp), as well as acylcarnitines associated with long-chain fatty acids and tricarboxylic acids such as citrate and succinate. Additionally, differences in metabolic profiling between SSc subtypes were identified. The diffuse cutaneous systemic sclerosis (dcSSc) subtype showed upregulated amino acid-related pathways involved in fibrosis, endothelial dysfunction, and gut dysbiosis. Lastly, potential biomarkers were evaluated for the diagnosis of SSc, the identification of the dcSSc subtype, pulmonary arterial hypertension, and interstitial lung disease. These potential biomarkers are within amino acids, nucleotides, carboxylic acids, and carbohydrate metabolism. Discussion: The altered metabolite mechanisms identified in this study mostly point to perturbations in amino acid-related pathways, fatty acid beta-oxidation, and in the tricarboxylic acid cycle, possibly associated with inflammation, vascular damage, fibrosis, and gut dysbiosis. Further studies in targeted metabolomics are required to evaluate potential biomarkers for diagnosis, prognosis, and treatment response.

Bioinformatics-based investigation on the genetic influence between SARS-CoV-2 infections and idiopathic pulmonary fibrosis (IPF) diseases, and drug repurposing

Some recent studies showed that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and idiopathic pulmonary fibrosis (IPF) disease might stimulate each other through the shared genes. Therefore, in this study, an attempt was made to explore common genomic biomarkers for SARS-CoV-2 infections and IPF disease highlighting their functions, pathways, regulators and associated drug molecules. At first, we identified 32 statistically significant common differentially expressed genes (cDEGs) between disease (SARS-CoV-2 and IPF) and control samples of RNA-Seq profiles by using a statistical r-package (edgeR). Then we detected 10 cDEGs (CXCR4, TNFAIP3, VCAM1, NLRP3, TNFAIP6, SELE, MX2, IRF4, UBD and CH25H) out of 32 as the common hub genes (cHubGs) by the protein-protein interaction (PPI) network analysis. The cHubGs regulatory network analysis detected few key TFs-proteins and miRNAs as the transcriptional and post-transcriptional regulators of cHubGs. The cDEGs-set enrichment analysis identified some crucial SARS-CoV-2 and IPF causing common molecular mechanisms including biological processes, molecular functions, cellular components and signaling pathways. Then, we suggested the cHubGs-guided top-ranked 10 candidate drug molecules (Tegobuvir, Nilotinib, Digoxin, Proscillaridin, Simeprevir, Sorafenib, Torin 2, Rapamycin, Vancomycin and Hesperidin) for the treatment against SARS-CoV-2 infections with IFP diseases as comorbidity. Finally, we investigated the resistance performance of our proposed drug molecules compare to the already published molecules, against the state-of-the-art alternatives publicly available top-ranked independent receptors by molecular docking analysis. Molecular docking results suggested that our proposed drug molecules would be more effective compare to the already published drug molecules. Thus, the findings of this study might be played a vital role for diagnosis and therapies of SARS-CoV-2 infections with IPF disease as comorbidity risk.

Identification of Tregs-Related Genes with Molecular Patterns in Patients with Systemic Sclerosis Related to ILD

Background: Systemic Sclerosis (SSc) is an autoimmune disease that is characterized by vasculopathy, digital ulcers, Raynaud’s phenomenon, renal failure, pulmonary arterial hypertension, and fibrosis. Regulatory T (Treg) cell subsets have recently been found to play crucial roles in SSc with interstitial lung disease (ILD) pathogenesis. This study investigates the molecular mechanism of Treg-related genes in SSc patients through bioinformatic analyses. Methods: The GSE181228 dataset of SSc was used in this study. CIBERSORT was used for assessing the category and proportions of immune cells in SSc. Random forest and least absolute shrinkage and selection operator (LASSO) regression analysis were used to select the hub Treg-related genes. Results: Through bioinformatic analyses, LIPN and CLEC4D were selected as hub Treg-regulated genes. The diagnostic power of the two genes separately for SSc was 0.824 and 0.826. LIPN was associated with the pathway of aminoacyl−tRNA biosynthesis, Primary immunodeficiency, DNA replication, etc. The expression of CLEC4D was associated with the pathway of Neutrophil extracellular trap formation, PPAR signaling pathway, Staphylococcus aureus infection, Systemic lupus erythematosus, TNF signaling pathway, and Toll−like receptor signaling pathway. Conclusion: Through bioinformatic analyses, we identified two Treg-related hub genes (LIPN, CLEC4D) that are mainly involved in the immune response and metabolism of Tregs in SSc with ILD. Moreover, our findings may provide the potential for studying the molecular mechanism of SSc with ILD.

Critical Role of LMCD1 in Promoting Profibrotic Characteristics of Lung Myofibroblasts in Experimental and Scleroderma-Associated Lung Fibrosis

OBJECTIVE

Interstitial lung disease (ILD) is a serious complication and leading cause of mortality in patients with systemic sclerosis (SSc). In this study, we explored the role of LIM and cysteine-rich domains protein 1 (LMCD1) as a novel factor in the pathogenesis of SSc-related ILD (SSc-ILD).

METHODS

The expression and effects of LMCD1 were studied in lung tissue samples and fibroblasts from SSc-ILD patients and control subjects as well as in lung tissue samples from animal models.

RESULTS

LMCD1 was consistently elevated in lung tissue samples and in fibroblasts isolated from SSc-ILD patients as compared to controls. Additionally, LMCD1 was found to be highly expressed in the lung in the fibroblast-specific protein (FSP)-driven, constitutively active transforming growth factor β receptor type I (TGFβR1) transgenic mouse model of ILD and the bleomycin-induced mouse model of ILD. In lung fibroblasts from SSc-ILD patients, LMCD1 is an essential factor for the TGFβ-induced generation of type I collagen, fibronectin, and α-smooth muscle actin (α-SMA). Depletion of LMCD1 by small interfering RNA reduced the expression of extracellular matrix proteins and lowered transcriptional activity and expression of α-SMA, as well as decreased the proliferation and contractile activity of SSc-ILD lung fibroblasts. In dense fibrotic areas of affected lung tissue, lung LMCD1 colocalized with α-SMA. In cultured scleroderma lung fibroblasts, LMCD1 colocalized and interacted with serum response factor which mediates LMCD1-induced contractile activity of lung fibroblasts.

CONCLUSION

Our study identifies LMCD1 as a profibrotic molecule contributing to the activation of myofibroblasts and the persistent fibroproliferation observed in SSc-ILD. Thus, LMCD1 may be a potential novel therapeutic target for patients with SSc-ILD.

First Characterization of the Transcriptome of Lung Fibroblasts of SSc Patients and Healthy Donors of African Ancestry

Systemic sclerosis (SSc) is a connective tissue disorder that results in fibrosis of the skin and visceral organs. SSc-associated pulmonary fibrosis (SSc-PF) is the leading cause of death amongst SSc patients. Racial disparity is noted in SSc as African Americans (AA) have a higher frequency and severity of disease than European Americans (EA). Using RNAseq, we determined differentially expressed genes (DEGs; q < 0.1, log2FC > |0.6|) in primary pulmonary fibroblasts from SSc lungs (SScL) and normal lungs (NL) of AA and EA patients to characterize the unique transcriptomic signatures of AA-NL and AA-SScL fibroblasts using systems-level analysis. We identified 69 DEGs in "AA-NL vs. EA-NL" and 384 DEGs in "AA-SScL vs. EA-SScL" analyses, and a comparison of disease mechanisms revealed that only 7.5% of DEGs were commonly deregulated in AA and EA patients. Surprisingly, we also identified an SSc-like signature in AA-NL fibroblasts. Our data highlight differences in disease mechanisms between AA and EA SScL fibroblasts and suggest that AA-NL fibroblasts are in a "pre-fibrosis" state, poised to respond to potential fibrotic triggers. The DEGs and pathways identified in our study provide a wealth of novel targets to better understand disease mechanisms leading to racial disparity in SSc-PF and develop more effective and personalized therapies.

Comparing clinical characteristics of systemic sclerosis with or without interstitial lung disease: A cross-sectional study from a single center of the Chinese Rheumatism Data Center

Background

We aimed to compare the clinical characteristics of patients with systemic sclerosis (SSc) with or without interstitial lung disease (ILD) to identify relationships with the presence of ILD in SSc at a single center in China.

Methods

A cross-sectional study was conducted using retrospective data from the Chinese Rheumatology Data Center. Patients diagnosed with SSc at the Second Affiliated Hospital of Nanchang University between 2013 and 2022 were included. Demographic and clinical characteristics were compared between patients with SSc with and without ILD. Logistic regression analyses were performed to explore these associations.

Results

A total of 227 patients with SSc were included (male:female ratio = 1:4.82), of which 121 (53.3%) were accompanied with ILD. SSc patients with ILD had a higher percentage of diffuse cutaneous systemic sclerosis (dcSSc), sclerodactyly, loss of finger pad, muscle involvement, left ventricular diastolic dysfunction (LVDD), and pulmonary hypertension (PAH), elevated Krebs von den Lungen-6 (KL-6), and elevated ferritin than those without ILD, and a higher modified Rodnan skin score (mRSS), neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) (all P < 0.05). Antinuclear antibody (ANA) and anti-scleroderma-70 (anti-Scl-70) positivity was presented frequently in SSc patients with ILD, while SSc patients without ILD were more often anti-centromere antibody (ACA) positive (all P < 0.05). On the multivariable analysis, muscle involvement [OR 2.551 (95% CI 1.054-6.175), P = 0.038], LVDD [OR 2.360 (95% CI 1.277-4.361), P = 0.006], PAH [OR 9.134 (95% CI 2.335-35.730), P = 0.001], dcSSc [OR 2.859 (95% CI 1.489-5.487), P = 0.002], PLR [OR 1.005 (95% CI 1.001-1.008), P = 0.020], elevated KL-6 [OR 2.033 (95% CI 1.099-3.763), P = 0.024], and anti-Scl-70 [OR 3.101 (95% CI 1.647-5.840), P < 0.001] were statistically significant associations with SSc patients with ILD.

Conclusion

Systemic sclerosis was found mainly in females. Several important differences in clinical and laboratory characteristics have been demonstrated between SSc patients with or without ILD. Muscle involvement, LVDD, PAH, dcSSc, PLR, elevated KL-6, and Anti-Scl-70 antibody may be associated with SSc in patients with ILD.

Biomarkers in Systemic Sclerosis Associated Interstitial Lung Disease (SSc-ILD)

Purpose of Review

Interstitial lung disease (ILD) is the leading cause of mortality in systemic sclerosis, a rare autoimmune disease characterised by fibrosis and vasculopathy. The variety of phenotypes in SSc-ILD have inspired multiple studies aimed at the identification of biomarkers which can provide disease-specific information but due to the complex pathogenesis of SSc-ILD, it has been challenging to validate such markers. We provide a comprehensive update on those most studied along with emerging biomarkers.

Recent Findings

We review the up-to-date findings with regard to the use of well-studied molecular biomarkers in SSc-ILD along with novel biomarkers offering promise as prognostic markers such as IGFBP-2 and IGFBP-7, the adipokine CTRP9, endothelial progenitor cells, and cellular markers such as CD21lo/neg B cells. Expression profiling data is being used in SSc patients to determine genetic and epigenetic clusters which shed further light on mechanisms involved in the pathogenesis of SSc-ILD and are likely to uncover novel biomarkers.

Summary

With the exception of autoantibodies, there are no routinely measured biomarkers in SSc-ILD and reliable validation of the many potential biomarkers is lacking. Identifying biomarkers which can offer diagnostic and prognostic certainty may help patients to receive preventative treatment as part of a personalised medicine approach.

The role of PET/CT in connective tissue disorders: systemic sclerosis, Sjögren's syndrome and systemic lupus erythematosus

Advanced imaging techniques are needed to help clinicians in the diagnosis, in the choice of the right time for therapeutic interventions or for modifications and monitoring of treatment response in patients with autoimmune connective tissue diseases. Nuclear medicine imaging, especially PET/CT and PET/MRI, may play an important role in detecting disease activity, assessing early treatment response as well as in clarifying the complex mechanisms underlying systemic sclerosis, Sjögren's syndrome or systemic lupus erythematosus. In addition, [¹⁸F]FDG PET/CT may help in excluding or detecting coexisting malignancies. Other more specific radiopharmaceuticals are being developed and investigated, targeting specific cells and molecules involved in connective tissue diseases. Further larger studies with standardized imaging protocol and image interpretation are strongly required before including PET/CT in the diagnostic work-up of subsets of patients with autoimmune connective tissue diseases.

The role of immune response in the pathogenesis of idiopathic pulmonary fibrosis: far beyond the Th1/Th2 imbalance

INTRODUCTION

. Idiopathic pulmonary fibrosis (IPF) is a chronic disease of unknown origin characterized by progressive scarring of the lung leading to irreversible loss of function. Despite the availability of two drugs that are able to slow down disease progression, IPF remains a deadly disease. The pathogenesis of IPF is poorly understood, but a dysregulated wound healing response following recurrent alveolar epithelial injury is thought to be crucial. Areas covered. In the last few years, the role of the immune system in IPF pathobiology has been reconsidered; indeed, recent data suggest that a dysfunctional immune system may promote and unfavorable interplay with pro-fibrotic pathways thus acting as a cofactor in disease development and progression. In this article, we review and critically discuss the role of T cells in the pathogenesis and progression of IPF in the attempt to highlight ways in which further research in this area may enable the development of targeted immunomodulatory therapies for this dreadful disease.

EXPERT OPINION

A better understanding of T cells interactions has the potential to facilitate the development of immune modulators targeting multiple T cell-mediated pathways thus halting disease initiation and progression.

Exploring the common pathophysiological links between IPF, SSc-ILD and post-COVID fibrosis

In coronavirus disease 2019 (COVID-19) patients, dysregulated release of matrix metalloproteinases occurs during the inflammatory phase of acute respiratory distress syndrome (ARDS), resulting in epithelial and endothelial injury with excessive fibroproliferation. COVID-19 resembles idiopathic pulmonary fibrosis (IPF) in several aspects. The fibrotic response in IPF is driven primarily by an abnormally activated alveolar epithelial cells (AECs) which release cytokines to activate fibroblasts. Endoplasmic reticulum (ER) stress is postulated to be one of the early triggers in both diseases. Systemic sclerosis (SSc) is a heterogeneous autoimmune rare connective tissue characterised by fibrosis of the skin and internal organs. Interstitial lung disease (ILD) is a common complication and the leading cause of SSc-related death. Several corollaries have been discussed in this paper for new drug development based on the pathogenic events in these three disorders associated with pulmonary fibrosis. A careful consideration of the similarities and differences in the pathogenic events associated with the development of lung fibrosis in post-COVID patients, IPF patients and patients with SSc-ILD may pave the way for precision medicine. Several questions need to be answered through research, which include the potential role of antifibrotics in managing IPF, SSc-ILD and post-COVID fibrosis. Many trials that are underway will ultimately shed light on their potency and place in therapy.

Spontaneous Pneumo-Mediastinum in a Post-COVID-19 Patient with Systemic Sclerosis

Pulmonary involvement is the most common cause of death among patients with systemic sclerosis (SSc). The current coronavirus disease 2019 (COVID-19) is particularly problematic to manage in SSc patients since they may experience a more severe evolution of COVID-19 due to the pre-existent interstitial lung disease (ILD) and the administration of immunosuppressive treatments. In addition, the remarkable radiological similarities between SSc-ILD and COVID-19 complicate the differential diagnosis between these two entities. Herein, we present the first case of spontaneous pneumo-mediastinum in a post-COVID-19 patient with SSc. In our patient, both smoking and pulmonary fibrosis could lead to cyst formation, which possibly spontaneously broke and caused pneumo-mediastinum. Moreover, megaesophagus perforation due to the smooth muscle atrophy, replacement with fibrosis, and achalasia may extend into the mediastinum or pleural space and has also been described as a rare case of spontaneous pneumo-pericardium. Finally, spontaneous pneumo-mediastinum and pneumothorax have been recently reported as an established complication of severe COVID-19 pneumonia and among COVID-19 long-term complication. This case report underlines that the worsening of respiratory symptoms in SSc patients, especially when recovered from COVID-19, requires further investigations for ruling out other tentative diagnoses besides the evolution of the SSc-ILD.

Persistent eosinophilia and associated organ involvement in Thai patients with systemic sclerosis: Data from the Siriraj scleroderma cohort

Objectives

This study aims to investigate the prevalence of persistent eosinophilia and associated organ complications in Thai patients with systemic sclerosis (SSc).

Patients and methods

This post-hoc study included 107 adult patients (23 males, 84 females; mean age: 50.4±11.6 years; range, 18 to 79 years) diagnosed with SSc between November 2013 and June 2017. Eosinophilia was defined as an absolute eosinophil count of >500/μL or a percentage count of >7%. Eosinophil levels collected at every visit over one year were categorized as persistently high (PH), persistently low (PL), high-to-low (HL), low-to-high (LH), or variable levels (VL). The study compared variables between PH and non-PH (PL+HL+LH+VL) groups. The patients with baseline eosinophilia were also identified and compared with the non-eosinophilia group.

Results

The median disease duration was 3.2 years. Of the patients, 79.4% had diffuse cutaneous SSc and 76.7% had anti-Scl-70 positivity. A total of 11.2%, 66.4%, 1.9%, 8.4%, and 12.1% of the patients were categorized into the PH, PL, HL, LH, and VL groups, respectively. Compared to non-PH groups, the PH group had a higher prevalence of anti-centromere antibody (ACA), higher baseline percent predicted total lung capacity, and lower baseline C-reactive protein and creatine phosphokinase (p<0.05 for all). The ACA positivity (odds ratio [OR]: 18.5; 95% confidence interval [CI]: 1.64-208.46) was associated with PH. The patients with baseline eosinophilia (17.8%) had a higher prevalence of non-specific interstitial pneumonia with periodic eosinophilia at the time of diagnosis (100% vs. 6.5%, p<0.0001; OR: 4.667; 95% CI: 1.712-12.724).

Conclusion

The PH was seldom (11%) in patients with SSc compared to periodic eosinophilia, which was more prevalent (18%). It may be related to ACA positivity and better pulmonary outcomes, whereas periodic eosinophilia may involve interstitial lung disease.

Peripheral Hybrid CB1R and iNOS Antagonist MRI-1867 Displays Anti-Fibrotic Efficacy in Bleomycin-Induced Skin Fibrosis

Scleroderma, or systemic sclerosis, is a multi-organ connective tissue disease resulting in fibrosis of the skin, heart, and lungs with no effective treatment. Endocannabinoids acting via cannabinoid-1 receptors (CB1R) and increased activity of inducible NO synthase (iNOS) promote tissue fibrosis including skin fibrosis, and joint targeting of these pathways may improve therapeutic efficacy. Recently, we showed that in mouse models of liver, lung and kidney fibrosis, treatment with a peripherally restricted hybrid CB1R/iNOS inhibitor (MRI-1867) yields greater anti-fibrotic efficacy than inhibiting either target alone. Here, we evaluated the therapeutic efficacy of MRI-1867 in bleomycin-induced skin fibrosis. Skin fibrosis was induced in C57BL/6J (B6) and Mdr1a/b-Bcrp triple knock-out (KO) mice by daily subcutaneous injections of bleomycin (2 IU/100 µL) for 28 days. Starting on day 15, mice were treated for 2 weeks with daily oral gavage of vehicle or MRI-1867. Skin levels of MRI-1867 and endocannabinoids were measured by mass spectrometry to assess target exposure and engagement by MRI-1867. Fibrosis was characterized histologically by dermal thickening and biochemically by hydroxyproline content. We also evaluated the potential increase of drug-efflux associated ABC transporters by bleomycin in skin fibrosis, which could affect target exposure to test compounds, as reported in bleomycin-induced lung fibrosis. Bleomycin-induced skin fibrosis was comparable in B6 and Mdr1a/b-Bcrp KO mice. However, the skin level of MRI-1867, an MDR1 substrate, was dramatically lower in B6 mice (0.023 µM) than in Mdr1a/b-Bcrp KO mice (8.8 µM) due to a bleomycin-induced increase in efflux activity of MDR1 in fibrotic skin. Furthermore, the endocannabinoids anandamide and 2-arachidonylglycerol were elevated 2-4-fold in the fibrotic vs. control skin in both mouse strains. MRI-1867 treatment attenuated bleomycin-induced established skin fibrosis and the associated increase in endocannabinoids in Mdr1a/b-Bcrp KO mice but not in B6 mice. We conclude that combined inhibition of CB1R and iNOS is an effective anti-fibrotic strategy for scleroderma. As bleomycin induces an artifact in testing antifibrotic drug candidates that are substrates of drug-efflux transporters, using Mdr1a/b-Bcrp KO mice for preclinical testing of such compounds avoids this pitfall.

Autologous stem-cell transplantation in systemic sclerosis-associated interstitial lung disease: early action in selected patients rather than escalation therapy for all

Systemic sclerosis (SSc) is a rare rheumatic disease characterised by inflammation, vasculopathy and fibrosis of skin and internal organs. A common complication and a leading cause of death in SSc is interstitial lung disease (ILD). The current armamentarium of treatments in SSc-ILD mainly includes immunosuppressive therapies and has recently been expanded with anti-fibrotic agent nintedanib. Autologous stem cell transplantation (SCT) is increasingly used in progressive diffuse cutaneous SSc. This intensive treatment has been studied in three randomised trials and demonstrated to improve survival and quality of life. In the subsets of patients with SSc-ILD, SCT resulted in stabilisation and modest improvement of lung volumes and disease extent on high resolution computed tomography, but less impact was seen on diffusion capacity. Comparison of SCT outcomes with results from SSc-ILD trials is difficult though, as lung involvement per se was not an inclusion criterion in all SCT trials. Also, baseline characteristics differed between studies. The risk of severe treatment-related complications from SCT is still considerable and patients with extensive lung disease are particularly at risk of complications during transplantation. Therefore SCT should only be provided by experienced multidisciplinary teams in carefully selected patients. Future research needs to include comprehensive pulmonary evaluation and establish whether SCT early in the disease might prevent irreversible pulmonary damage and reduce treatment-related complications. Also, more insight in mechanisms of action of SCT in the lung and predictors for response will improve the use of this treatment in SSc-ILD. In this review the role of SCT in the treatment of SSc-ILD is summarised.

The rationale for targeting the JAK/STAT pathway in scleroderma-associated interstitial lung disease

The etiopathogenesis of systemic sclerosis (SSc)-associated interstitial lung disease (ILD) is still debated and no therapeutic options have proved fully effective to date. The intracellular Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway is highly conserved among either immune or nonimmune cells and involved in inflammation and fibrosis. Evidence from preclinical studies shows that the JAK/STAT signaling cascade has a crucial role in the differentiation of autoreactive cells as well as in the extracellular matrix remodeling that occurs in SSc. Therefore, it is likely that the use of oral small molecule JAK-inhibitors, especially if prescribed early, may prevent or slow the progression of SSc-associated ILD, but few clinical studies currently support this hypothesis.

Potential Biomarkers in Systemic Sclerosis: A Literature Review and Update

Systemic sclerosis (SSc) is a chronic autoimmune disease characterized by dysregulation of the immune system, vascular damage, and fibrosis of the skin and internal organs. Patients with SSc show a heterogeneous phenotype and a range of clinical courses. Therefore, biomarkers that are helpful for precise diagnosis, prediction of clinical course, and evaluation of the therapeutic responsiveness of disease are required in clinical practice. SSc-specific autoantibodies are currently used for diagnosis and prediction of clinical features, as other biomarkers have not yet been fully vetted. Krebs von den Lungen-6 (KL-6), surfactant protein-D (SP-D), and CCL18 have been considered as serum biomarkers of SSc-related interstitial lung disease. Moreover, levels of circulating brain natriuretic peptide (BNP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) can provide diagnostic information and indicate the severity of pulmonary arterial hypertension. Assessment of several serum/plasma cytokines, chemokines, growth factors, adhesion molecules, and other molecules may also reflect the activity or progression of fibrosis and vascular involvement in affected organs. Recently, microRNAs have also been implicated as possible circulating indicators of SSc. In this review, we focus on several potential SSc biomarkers and discuss their clinical utility.

Interstitial Lung Disease in Patients With Systemic Sclerosis: Toward Personalized-Medicine-Based Prediction and Drug Screening Models of Systemic Sclerosis-Related Interstitial Lung Disease (SSc-ILD)

Systemic sclerosis (SSc) is an autoimmune connective tissue disease, characterized by immune dysregulation and progressive fibrosis. Interstitial lung disease (ILD) is the most common cause of death among SSc patients and there are currently very limited approved disease-modifying treatment options for systemic sclerosis-related interstitial lung disease (SSc-ILD). The mechanisms underlying pulmonary fibrosis in SSc-ILD are not completely unraveled, and knowledge on fibrotic processes has been acquired mostly from studies in idiopathic pulmonary fibrosis (IPF). The incomplete knowledge of SSc-ILD pathogenesis partly explains the limited options for disease-modifying therapy for SSc-ILD. Fibrosis in IPF appears to be related to aberrant repair following injury, but whether this also holds for SSc-ILD is less evident. Furthermore, immune dysregulation appears to contribute to pro-fibrotic responses in SSc-ILD, perhaps more than in IPF. In addition, SSc-ILD patient heterogeneity complicates the understanding of the underlying mechanisms of disease development, and more importantly, limits correct clinical diagnosis and treatment effectivity. Therefore, there is an unmet need for patient-relevant (in vitro) models to examine patient-specific disease pathogenesis, predict disease progression, screen appropriate treatment regimens and identify new targets for treatment. Technological advances in in vitro patient-relevant disease modeling, including (human induced pluripotent stem cell (hiPSC)-derived) lung epithelial cells, organoids and organ-on-chip technology offer a platform that has the potential to contribute to unravel the underlying mechanisms of SSc-ILD development. Combining these models with state-of-the-art analysis platforms, including (single cell) RNA sequencing and (imaging) mass cytometry, may help to delineate pathogenic mechanisms and define new treatment targets of SSc-ILD.

Pulmonary involvement in systemic sclerosis: exploring cellular, genetic and epigenetic mechanisms

Systemic sclerosis (SSc) is a chronic progressive autoimmune disease characterized by immune inflammation, vasculopathy, and fibrosis. There are still numerous uncertainties in the understanding of disease initiation and progression. Pulmonary involvement in SSc, and particularly pulmonary fibrosis, is critical for all organ systems affections in this disease. This review is aimed to describe and analyze new findings in the pathophysiology of SSc-associated pulmonary involvement and to explore perspective diagnostic and therapeutic strategies. A myriad of cellular interactions is explored in the dynamics of progressive interstitial lung disease (ILD) and pulmonary hypertension (PH) in SSc. The role of exosomes, microvesicles, and apoptotic bodies is examined and the impact of micro and long non-coding RNAs, DNA methylation, and histone modification in SSc is discussed.

Emerging Roles of Matricellular Proteins in Systemic Sclerosis

Systemic sclerosis is a rare chronic heterogenous disease that involves inflammation and vasculopathy, and converges in end-stage development of multisystem tissue fibrosis. The loss of tight spatial distribution and temporal expression of proteins in the extracellular matrix (ECM) leads to progressive organ stiffening, which is a hallmark of fibrotic disease. A group of nonstructural matrix proteins, known as matricellular proteins (MCPs) are implicated in dysregulated processes that drive fibrosis such as ECM remodeling and various cellular behaviors. Accordingly, MCPs have been described in the context of fibrosis in sclerosis (SSc) as predictive disease biomarkers and regulators of ECM synthesis, with promising therapeutic potential. In this present review, an informative summary of major MCPs is presented highlighting their clear correlations to SSc- fibrosis.

Etiology, Risk Factors, and Biomarkers in Systemic Sclerosis with Interstitial Lung Disease

Systemic sclerosis (SSc) is a complex, multiorgan, autoimmune disease. Lung fibrosis occurs in ∼80% of patients with SSc; 25% to 30% develop progressive interstitial lung disease (ILD). The pathogenesis of fibrosis in SSc-associated ILD (SSc-ILD) involves cellular injury, activation/differentiation of mesenchymal cells, and morphological/biological changes in epithelial/endothelial cells. Risk factors for progressive SSc-ILD include older age, male sex, degree of lung involvement on baseline high-resolution computed tomography imaging, reduced Dl_CO, and reduced FVC. SSc-ILD does not share the genetic risk architecture observed in idiopathic pulmonary fibrosis (IPF), with key risk factors yet to be identified. Presence of anti-Scl-70 antibodies and absence of anti-centromere antibodies indicate increased likelihood of progressive ILD. Elevated levels of serum Krebs von den Lungen-6 and C-reactive protein are both associated with SSc-ILD severity and predict SSc-ILD progression. A promising prognostic indicator is serum chemokine (C-C motif) ligand 18. SSc-ILD shares similarities with IPF, although clear differences exist. Histologically, a nonspecific interstitial pneumonia pattern is commonly observed in SSc-ILD, whereas IPF is defined by usual interstitial pneumonia. The course of SSc-ILD is variable, ranging from minor, stable disease to a progressive course, whereas all patients with IPF experience progression of disease. Although appropriately treated patients with SSc-ILD have better chances of stabilization and survival, a relentlessly progressive course, akin to IPF, is seen in a minority. Better understanding of cellular and molecular pathogenesis, genetic risk, and distinctive features of SSc-ILD and identification of robust prognostic biomarkers are needed for optimal disease management.

Predictors of progression in systemic sclerosis patients with interstitial lung disease

Systemic sclerosis (SSc) is a systemic autoimmune disease affecting multiple organ systems, including the lungs. Interstitial lung disease (ILD) is the leading cause of death in SSc.

There are no valid biomarkers to predict the occurrence of SSc-ILD, although auto-antibodies against anti-topoisomerase I and several inflammatory markers are candidate biomarkers that need further evaluation. Chest auscultation, presence of shortness of breath and pulmonary function testing are important diagnostic tools, but lack sensitivity to detect early ILD. Baseline screening with high-resolution computed tomography (HRCT) is therefore necessary to confirm an SSc-ILD diagnosis. Once diagnosed with SSc-ILD, patients' clinical courses are variable and difficult to predict, although certain patient characteristics and biomarkers are associated with disease progression. It is important to monitor patients with SSc-ILD for signs of disease progression, although there is no consensus about which diagnostic tools to use or how often monitoring should occur. In this article, we review methods used to define and predict disease progression in SSc-ILD.

There is no valid definition of SSc-ILD disease progression, but we suggest that either a decline in forced vital capacity (FVC) from baseline of ≥10%, or a decline in FVC of 5–9% in association with a decline in diffusing capacity of the lung for carbon monoxide of ≥15% represents progression. An increase in the radiographic extent of ILD on HRCT imaging would also signify progression. A time period of 1–2 years is generally used for this definition, but a decline over a longer time period may also reflect clinically relevant disease progression.

Lung function tests and chest imaging help predict who has SSc-associated ILD and whether it will progress. In the absence of standardised methods for doctors, we recommend a strategy that combines both lung function tests and chest imaging.http://bit.ly/2uK9ZD2

Baicalin alleviates bleomycin‑induced pulmonary fibrosis and fibroblast proliferation in rats via the PI3K/AKT signaling pathway

Baicalin is an important flavonoid compound THAT is isolated from the Scutellaria baicalensis Georgi Chinese herb and plays a critical role in anti‑oxidative, anti‑inflammatory, anti‑infection and anti‑tumor functions. Although baicalin can suppress the proliferation of tumor cells, the underlying mechanisms of baicalin in bleomycin (BLM)‑induced pulmonary fibrosis remain to be elucidated. Thus, the aim of the present study was to determine the role of baicalin in pulmonary fibrosis and fibroblast proliferation in rats. Hematoxylin and eosin (H&E) and Masson staining were used to measure the morphology of pulmonary fibrosis, ELIASA kits were used to test the ROS and inflammation, and western blotting and TUNEL were performed to study the apoptosis proteins. In vitro, MTT assay, flow cytometry, western blotting and immunofluorescence were performed to investigate the effects of baicalin on proliferation of fibroblasts. The most significantly fibrotic changes were identified in the lungs of model rats at day 28. Baicalin (50 mg/kg) attenuated the degree of pulmonary fibrosis, and the hydroxyproline content of the lung tissues was decreased in the baicalin group, compared with the BLM group. Further investigation revealed that baicalin significantly increased glutathione peroxidase (GSH‑px), total‑superoxide dismutase (T‑SOD) and glutathione (GSH) levels, whilst decreasing that of serum malondialdehyde (MDA). TUNEL‑positive cells were significantly decreased in rats treated with baicalin group, compared with the model group. Furthermore, it was found that BLM promoted fibroblasts viability in a dose‑dependent manner in vivo, which was restricted following treatment with different concentrations of baicalin. Moreover, BLM promoted the expression levels of cyclin A, D and E, proliferating cell nuclear antigen, phosphorylated (p)‑AKT and p‑calcium/calmodulin‑dependent protein kinase type. BLM also promoted the transition of cells from the G0/G1 phase to the G2/M and S phases, and increased the intracellular Ca2+ concentration, which was subsequently suppressed by baicalin. Collectively, the results of the present study suggested that baicalin exerted a suppressive effect on BLM‑induced pulmonary fibrosis and fibroblast proliferation.

A Defect in Thymic Tolerance Causes T Cell-Mediated Autoimmunity in a Murine Model of COPA Syndrome

COPA syndrome is a recently described Mendelian autoimmune disorder caused by missense mutations in the coatomer protein complex subunit α (COPA) gene. Patients with COPA syndrome develop arthritis and lung disease that presents as pulmonary hemorrhage or interstitial lung disease (ILD). Immunosuppressive medications can stabilize the disease, but many patients develop progressive pulmonary fibrosis, which requires life-saving measures, such as lung transplantation. Because very little is understood about the pathogenesis of COPA syndrome, it has been difficult to devise effective treatments for patients. To date, it remains unknown which cell types are critical for mediating the disease as well as the mechanisms that lead to autoimmunity. To explore these issues, we generated a Copa^E241K/+ germline knock-in mouse bearing one of the same Copa missense mutations in patients. Mutant mice spontaneously developed ILD that mirrors lung pathology in patients, as well as elevations of activated cytokine-secreting T cells. In this study, we show that mutant Copa in epithelial cells of the thymus impairs the thymic selection of T cells and results in both an increase in autoreactive T cells and decrease in regulatory T cells in peripheral tissues. We demonstrate that T cells from Copa^E241K/+ mice are pathogenic and cause ILD through adoptive transfer experiments. In conclusion, to our knowledge, we establish a new mouse model of COPA syndrome to identify a previously unknown function for Copa in thymocyte selection and demonstrate that a defect in central tolerance is a putative mechanism by which COPA mutations lead to autoimmunity in patients.

Systemic sclerosis-associated interstitial lung disease

Systemic sclerosis is an autoimmune connective tissue disease, which is characterised by immune dysregulation and progressive fibrosis that typically affects the skin, with variable internal organ involvement. It is a rare condition that affects mostly young and middle-aged women, resulting in disproportionate morbidity and mortality. Currently, interstitial lung disease is the most common cause of death among patients with systemic sclerosis, with a prevalence of up to 30% and a 10-year mortality of up to 40%. Interstitial lung disease is more common among African Americans and in people with the diffuse cutaneous form of systemic sclerosis or anti-topoisomerase 1 antibodies. Systemic sclerosis-associated interstitial lung disease most commonly presents with dyspnoea, cough, and a non-specific interstitial pneumonia pattern on CT scan, with a minority of cases fulfilling the criteria for usual interstitial pneumonia. The standard therapy has traditionally been combinations of immunosuppressants, particularly mycophenolate mofetil or cyclophosphamide. These immunosuppressants can be supplemented by targeted biological and antifibrotic therapies, whereas autologous haematopoietic stem-cell transplantation and lung transplantation are reserved for refractory cases.

Mutations of FAM111B gene are not associated with Systemic Sclerosis

Systemic sclerosis (SSc) is a prototypic systemic fibrotic disease with unclearly characterized genetic basis. We have discovered that mutations in family with sequence similarity 111, member B (FAM111B) gene cause hereditary fibrosing poikiloderma with tendon contractures, myopathy, and pulmonary fibrosis, a multisystem fibrotic condition with clinical similarities to SSc. This observation has established FAM111B as a candidate gene for SSc.

PATIENTS AND METHODS

Demographic and clinical characteristics of consenting adults with definite SSc were recorded. Blood DNA analysis was performed using the High-Resolution Melt technique, and samples with abnormal electropherograms were selected for Sanger sequencing to identify mutations. Ethnically-matched controls from the general South African population were used to verify the frequency of variants in FAM111B. Public databases such as 1000 Genomes and ExAC were also used to verify the frequency of variants in FAM111B.

RESULTS

Of 131 patients, 118 (90.1%) were female, and 78 (59.5%) were black Africans. Genetic analysis revealed two FAM111B genetic variants. The c.917 A > G variant (rs200497516) was found in one SSc patients, and one control, and was classified as a missense variant of unknown significance. The c.988 C > T variant (rs35732637) occurred in three SSc patients and 42/243 (17.3%) of healthy controls, and is a known polymorphism.

CONCLUSION

One rare variant was found in a patient with SSc but has no functional or structural impact on the FAM111B gene. In this cohort, FAM111B gene mutations are not associated with SSc.

Treatment of Systemic Sclerosis-related Interstitial Lung Disease: A Review of Existing and Emerging Therapies

Although interstitial lung disease accounts for the majority of deaths of patients with systemic sclerosis, treatment options for this manifestation of the disease are limited. Few high-quality, randomized, controlled trials exist for systemic sclerosis-related interstitial lung disease, and historically, studies have favored the use of cyclophosphamide. However, the benefit of cyclophosphamide for this disease is tempered by its complex adverse event profile. More recent studies have demonstrated the effectiveness of mycophenolate for systemic sclerosis-related interstitial lung disease, including Scleroderma Lung Study II. This review highlights the findings of this study, which was the first randomized controlled trial to compare cyclophosphamide with mycophenolate for the treatment of systemic sclerosis-related interstitial lung disease. The results reported in this trial suggest that there is no difference in treatment efficacy between mycophenolate and cyclophosphamide; however, mycophenolate appears to be safer and more tolerable than cyclophosphamide. In light of the ongoing advances in our understanding of the pathogenic mechanisms underlying interstitial lung disease in systemic sclerosis, this review also summarizes novel treatment approaches, presenting clinical and preclinical evidence for rituximab, tocilizumab, pirfenidone, and nintedanib, as well as hematopoietic stem cell transplantation and lung transplantation. This review further explores how reaching a consensus on appropriate study end points, as well as trial enrichment criteria, is central to improving our ability to judiciously evaluate the safety and efficacy of emerging experimental therapies for systemic sclerosis-related interstitial lung disease.

Role of allograft inflammatory factor-1 in bleomycin-induced lung fibrosis

Allograft inflammatory factor-1 (AIF-1) is a protein expressed by macrophages infiltrating the area around the coronary arteries in a rat ectopic cardiac allograft model. We previously reported that AIF-1 is associated with the pathogenesis of rheumatoid arthritis and skin fibrosis in sclerodermatous graft-versus-host disease mice. Here, we used an animal model of bleomycin-induced lung fibrosis to analyze the expression of AIF-1 and examine its function in lung fibrosis. The results showed that AIF-1 was expressed on lung tissues, specifically macrophages, from mice with bleomycin-induced lung fibrosis. Recombinant AIF-1 increased the production of TGF-β which plays crucial roles in the mechanism of fibrosis by mouse macrophage cell line RAW264.7. Recombinant AIF-1 also increased both the proliferation and migration of lung fibroblasts compared with control group. These results suggest that AIF-1 plays an important role in the mechanism underlying lung fibrosis, and may provide an attractive new therapeutic target.

Clinical and serological features of systemic sclerosis in a multicenter African American cohort: Analysis of the genome research in African American scleroderma patients clinical database

Racial differences exist in the severity of systemic sclerosis (SSc). To enhance our knowledge about SSc in African Americans, we established a comprehensive clinical database from the largest multicenter cohort of African American SSc patients assembled to date (the Genome Research in African American Scleroderma Patients (GRASP) cohort).African American SSc patients were enrolled retrospectively and prospectively over a 30-year period (1987-2016), from 18 academic centers throughout the United States. The cross-sectional prevalence of sociodemographic, clinical, and serological features was evaluated. Factors associated with clinically significant manifestations of SSc were assessed using multivariate logistic regression analyses.The study population included a total of 1009 African American SSc patients, comprised of 84% women. In total, 945 (94%) patients met the 2013 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria for SSc, with the remaining 64 (6%) meeting the 1980 ACR or CREST (calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, telangiectasia) criteria. While 43% were actively employed, 33% required disability support. The majority (57%) had the more severe diffuse subtype and a young age at symptom onset (39.1 ± 13.7 years), in marked contrast to that reported in cohorts of predominantly European ancestry. Also, 1 in 10 patients had a severe Medsger cardiac score of 4. Pulmonary fibrosis evident on computed tomography (CT) chest was present in 43% of patients and was significantly associated with anti-topoisomerase I positivity. 38% of patients with CT evidence of pulmonary fibrosis had a severe restrictive ventilator defect, forced vital capacity (FVC) ≤50% predicted. A significant association was noted between longer disease duration and higher odds of pulmonary hypertension, telangiectasia, and calcinosis. The prevalence of potentially fatal scleroderma renal crisis was 7%, 3.5 times higher than the 2% prevalence reported in the European League Against Rheumatism Scleroderma Trials and Research (EUSTAR) cohort.Our study emphasizes the unique and severe disease burden of SSc in African Americans compared to those of European ancestry.

D1398G Variant of MET Is Associated with Impaired Signaling of Hepatocyte Growth Factor in Alveolar Epithelial Cells and Lung Fibroblasts

Pulmonary fibrosis represents the terminal stage of a diverse group of lung diseases including scleroderma associated interstitial lung disease. The molecular mechanisms underlying the pathogenesis of lung fibrosis are not well understood and there is a great need for more effective treatment for this lethal disease. We recently discovered a small fragment of hepatocyte growth factor (HGF) receptor MET as a peptide designated “M10,” with strong antifibrotic properties. Furthermore, we showed that aspartic acid at position 1398 of MET is essential for M10 generation. The current study was undertaken to investigate the D1398G variant of MET in which aspartic acid at position 1398 was mutated to glycine resulting in loss of M10. We demonstrate that lung fibroblasts, A549, and primary alveolar epithelial cells (AEC) expressing D1398G MET exhibit reduced auto-phosphorylation on tyrosine residues and reduced activation of Ras and MAPK. HGF treatment of scleroderma lung fibroblasts as well as HGF treatment of TGFβ-treated normal lung fibroblasts transfected with wild type MET is associated with decreased collagen, connective tissue growth factor (CTGF, CCN2) and smooth muscle α-actin (SMA). However, HGF has no such effects in cells transfected with MET D1398G. Cisplatin- and FasL-induced apoptosis is significantly reduced in AEC transfected with MET wild type, but not in AEC transfected with MET D1398G. We conclude that the D1398G variant of MET is associated with compromised phosphorylation and impaired HGF signaling in lung fibroblasts and AEC, two cell types implicated in the pathogenesis of pulmonary fibrosis associated with scleroderma. Ongoing studies will explore the frequency of this variant and its relationship to pulmonary outcomes in scleroderma patients.

Association of elevated α-defensin levels with interstitial pneumonia in patients with systemic sclerosis

Background

Interstitial lung disease (ILD) is the leading cause of mortality in patients with systemic sclerosis (SSc). Although the pathogenesis of SSc-ILD is not well understood, neutrophils may play a pivotal role in this process. Neutrophils store azurophil granules that contain defensins, antimicrobial peptides that function in regulating the inflammatory response, and IL-8, a potent chemoattractant for neutrophils. The present study evaluated the levels of defensins and IL-8 in patients with SSc-ILD to determine their roles in disease pathogenesis.

Methods

Defensins (also known as human neutrophil peptides, HNPs) and IL-8 levels were measured in the serum and bronchoalveolar lavage fluid (BALF) of 33 patients with SSc-ILD and in 20 healthy controls by using ELISA.

Results

BALF analysis revealed a significant increase in HNPs in SSc-ILD patients (median; 240.0 pg/mL) than that of healthy controls (79.7 pg/mL). Additionally, IL-8 levels were higher in SSc-ILD patient serum and BALF as compared to healthy controls (16.4 pg/mL vs. 5.8 pg/mL and 15.4 pg/mL vs. 14.5 pg/mL, respectively). However, plasma HNPs levels were relatively unchanged. HNP and IL-8 levels in patient BALF displayed a significant positive correlation significantly correlated (r = 0.774, p <0.01), and which also correlated with clinical disease parameters—such as ILD biomarkers, pulmonary function tests, ratio of neutrophils and eosinophils in BALF, tricuspid regurgitation peak gradient (TRPG), and the extent of high-resolution computed tomography (HRCT) findings in the lung. Levels of plasma HNPs and serum IL-8 did not show a significant correlation with any clinical parameter. SSc-ILD progression was evaluated by pulmonary function tests, but no association was observed between VC change ratios and HNPs or IL-8 levels.

Conclusions

BALF levels of HNPs and IL-8 were higher in SSc-ILD than in healthy controls, and are associated with various clinical disease parameters. Further studies are needed to clarify the role of defensins and IL-8 in SSc-ILD pathogenesis.

Interstitial lung disease in scleroderma

Systemic sclerosis is a heterogeneous disease of unknown etiology with limited effective therapies. It is characterized by autoimmunity, vasculopathy, and fibrosis and is clinically manifested by multiorgan involvement. Interstitial lung disease is a common complication of systemic sclerosis and is associated with significant morbidity and mortality. The diagnosis of interstitial lung disease hinges on careful clinical evaluation and pulmonary function tests and high-resolution computed tomography. Effective therapeutic options are still limited. Several experimental therapies are currently in early-phase clinical trials and show promise.