Abnormalities in the regulators of angiogenesis in patients with scleroderma

Nailfold capillaroscopy and candidate-biomarker levels in systemic sclerosis-associated pulmonary hypertension: A cross-sectional study

Objectives

Pulmonary hypertension is one of the leading causes of death in systemic sclerosis. Early detection and treatment of pulmonary hypertension in systemic sclerosis is crucial. Nailfold capillaroscopy microscopy, vascular autoantibodies AT1R and ETAR, and several candidate-biomarkers have the potential to serve as noninvasive tools to identify systemic sclerosis patients at risk for developing pulmonary hypertension. Here, we explore the classifying potential of nailfold capillaroscopy microscopy characteristics and serum levels of selected candidate-biomarkers in a sample of systemic sclerosis patients with and without different forms of pulmonary hypertension.

Methods

A total of 81 consecutive systemic sclerosis patients were included, 40 with systemic sclerosis pulmonary hypertension and 41 with no pulmonary hypertension. In each group, quantitative and qualitative nailfold capillaroscopy microscopy characteristics, vascular autoantibodies AT1R and ETAR, and serum levels of 24 soluble serum factors were determined. For evaluation of the nailfold capillaroscopy microscopy characteristics, linear regression analysis accounting for age, sex, and diffusing capacity of the lungs for carbon monoxide percentage predicted was used. Autoantibodies and soluble serum factor levels were compared using two-sample t test with equal variances.

Results

No statistically significant differences were observed in quantitative or qualitative nailfold capillaroscopy microscopy characteristics, or vascular autoantibody ETAR and AT1R titer between systemic sclerosis-pulmonary hypertension and systemic sclerosis-no pulmonary hypertension. In contrast, several serum levels of soluble factors differed between groups: Endostatin, sVCAM, and VEGFD were increased, and CXCL4, sVEGFR2, and PDGF-AB/BB were decreased in systemic sclerosis-pulmonary hypertension. Random forest classification identified Endostatin and CXCL4 as the most predictive classifiers to distinguish systemic sclerosispulmonary hypertension from systemic sclerosis-no pulmonary hypertension.

Conclusion

This study shows the potential for several soluble serum factors to distinguish systemic sclerosis-pulmonary hypertension from systemic sclerosis-no pulmonary hypertension. We found no classifying potential for qualitative or quantitative nailfold capillaroscopy microscopy characteristics, or vascular autoantibodies.

Current Trends in Vascular Biomarkers for Systemic Sclerosis: A Narrative Review

Systemic sclerosis (SSc, scleroderma) is a multifaceted rare connective tissue disease whose pathogenesis is dominated by immune dysregulation, small vessel vasculopathy, impaired angiogenesis, and both cutaneous and visceral fibrosis. Microvascular impairment represents the initial event of the disease, preceding fibrosis by months or years and accounting for the main disabling and/or life-threatening clinical manifestations, including telangiectasias, pitting scars, periungual microvascular abnormalities (e.g., giant capillaries, hemorrhages, avascular areas, ramified/bushy capillaries) clinically detectable by nailfold videocapillaroscopy, ischemic digital ulcers, pulmonary arterial hypertension, and scleroderma renal crisis. Despite a variety of available treatment options, treatment of SSc-related vascular disease remains problematic, even considering SSc etherogenity and the quite narrow therapeutic window. In this context, plenty of studies have highlighted the great usefulness in clinical practice of vascular biomarkers allowing clinicians to assess the evolution of the pathological process affecting the vessels, as well as to predict the prognosis and the response to therapy. The current narrative review provides an up-to-date overview of the main candidate vascular biomarkers that have been proposed for SSc, focusing on their main reported associations with characteristic clinical vascular features of the disease.

Proteomic aptamer analysis reveals serum markers that characterize preclinical systemic sclerosis (SSc) patients at risk for progression toward definite SSc

BACKGROUND

The study of molecular mechanisms characterizing disease progression may be relevant to get insights into systemic sclerosis (SSc) pathogenesis and to intercept patients at very early stage. We aimed at investigating the proteomic profile of preclinical systemic sclerosis (PreSSc) via a discovery/validation two-step approach.

METHODS

SOMAcan aptamer-based analysis was performed on a serum sample of 13 PreSSc (discovery cohort) according to 2001 LeRoy and Medsger criteria (characterized solely by Raynaud phenomenon plus a positive nailfold capillaroscopy and SSc-specific antibodies without any other sign of definite disease) and 8 healthy controls (HCs) age, gender, and ethnicity matched. Prospective data were available up to 4±0.6 years to determine the progression to definite SSc according to the EULAR/ACR 2013 classification criteria. In proteins with relative fluorescence units (RFU) > |1.5|-fold vs HCs values, univariate analysis was conducted via bootstrap aggregating models to determine the predicting accuracy (progression vs non-progression) of categorized baseline protein values. Gene Ontologies (GO terms) and Reactome terms of significant proteins at the adjusted 0.05 threshold were explored. Significant proteins from the discovery cohort were finally validated via ELISAs in an independent validation cohort of 50 PreSSc with clinical prospective data up to 5 years. Time-to-event analysis for interval-censored data was used to evaluate disease progression.

RESULTS

In the discovery cohort, 286 out of 1306 proteins analyzed via SomaScan, were differentially expressed versus HCs. Ten proteins were significantly associated with disease progression; analysis through GO and Reactome showed differentially enriched pathways involving angiogenesis, endothelial cell chemotaxis, and endothelial cell chemotaxis to fibroblast growth factor (FGF). In the validation cohort, endostatin (HR=10.23, CI95=2.2-47.59, p=0.003) was strongly associated with disease progression, as well as bFGF (HR=0.84, CI95=0.709-0.996, p=0.045) and PAF-AHβ (HR=0.372, CI95=0.171-0.809, p=0.013) CONCLUSIONS: A distinct protein profile characterized PreSSc from HCs and proteins associated with hypoxia, vasculopathy, and fibrosis regulation are linked with the progression from preclinical to definite SSc. These proteins, in particular endostatin, can be regarded both as markers of severity and molecules with pathogenetic significance as well as therapeutic targets.

Targeting integrin pathways: mechanisms and advances in therapy

Integrins are considered the main cell-adhesion transmembrane receptors that play multifaceted roles as extracellular matrix (ECM)-cytoskeletal linkers and transducers in biochemical and mechanical signals between cells and their environment in a wide range of states in health and diseases. Integrin functions are dependable on a delicate balance between active and inactive status via multiple mechanisms, including protein-protein interactions, conformational changes, and trafficking. Due to their exposure on the cell surface and sensitivity to the molecular blockade, integrins have been investigated as pharmacological targets for nearly 40 years, but given the complexity of integrins and sometimes opposite characteristics, targeting integrin therapeutics has been a challenge. To date, only seven drugs targeting integrins have been successfully marketed, including abciximab, eptifibatide, tirofiban, natalizumab, vedolizumab, lifitegrast, and carotegrast. Currently, there are approximately 90 kinds of integrin-based therapeutic drugs or imaging agents in clinical studies, including small molecules, antibodies, synthetic mimic peptides, antibody-drug conjugates (ADCs), chimeric antigen receptor (CAR) T-cell therapy, imaging agents, etc. A serious lesson from past integrin drug discovery and research efforts is that successes rely on both a deep understanding of integrin-regulatory mechanisms and unmet clinical needs. Herein, we provide a systematic and complete review of all integrin family members and integrin-mediated downstream signal transduction to highlight ongoing efforts to develop new therapies/diagnoses from bench to clinic. In addition, we further discuss the trend of drug development, how to improve the success rate of clinical trials targeting integrin therapies, and the key points for clinical research, basic research, and translational research.

Ameliorating Fibrosis in Murine and Human Tissues with END55, an Endostatin-Derived Fusion Protein Made in Plants

Organ fibrosis, particularly of the lungs, causes significant morbidity and mortality. Effective treatments are needed to reduce the health burden. A fragment of the carboxyl-terminal end of collagen XVIII/endostatin reduces skin and lung fibrosis. This fragment was modified to facilitate its production in plants, which resulted in the recombinant fusion protein, END55. We found that expression of END55 had significant anti-fibrotic effects on the treatment and prevention of skin and lung fibrosis in a bleomycin mouse model. We validated these effects in a second mouse model of pulmonary fibrosis involving inducible, lung-targeted expression of transforming growth factor β1. END55 also exerted anti-fibrotic effects in human lung and skin tissues maintained in organ culture in which fibrosis was experimentally induced. The anti-fibrotic effect of END55 was mediated by a decrease in the expression of extracellular matrix genes and an increase in the levels of matrix-degrading enzymes. Finally, END55 reduced fibrosis in the lungs of patients with systemic sclerosis (SSc) and idiopathic pulmonary fibrosis (IPF) who underwent lung transplantation due to the severity of their lung disease, displaying efficacy in human tissues directly relevant to human disease. These findings demonstrate that END55 is an effective anti-fibrotic therapy in different organs.

Multiple variants of soluble CD146 are involved in Systemic Sclerosis: identification of a novel pro-fibrotic factor

OBJECTIVE

Systemic sclerosis (SSc) is an autoimmune disorder characterized by excessive fibrosis, immune dysfunction and vascular damages, in which expression of many growth factors is deregulated. CD146 was recently described as a major actor in SSc. As CD146 also exists as a circulating soluble form (sCD146) acting as a growth factor in numerous angiogenic- and inflammatory-related pathologies, we sought to identify the mechanisms underlying the generation of sCD146 and characterized the regulation and functions of the different identified variants in SSc.

METHODS

To this end, we performed in vitro experiments, including RNA-seq and antibody arrays, and in vivo experiments using animal models of SSc induced by bleomycin and of hindlimb ischemia.

RESULTS

Multiple forms of sCD146, generated by both shedding and alternative splicing of the primary transcript, were discovered. The shed form of sCD146 was generated from the cleavage of both long and short membrane isoforms of membrane CD146 through Adam10 and Tace metalloproteinases, respectively. In addition, two novel sCD146 splice variants, I5-13-sCD146 and I10-sCD146 were identified. Of interest, I5-13-sCD146 was significantly increased in sera of SSc patients, in particular in patients with pulmonary fibrosis, whereas I10-sCD146 was decreased. Further experiments revealed that shed sCD146 and I10-sCD146 displayed pro-angiogenic activity through FAK and PKCε signalling pathways, respectively, whereas I5-13-sCD146 displayed pro-fibrotic effects through wint1/β-catenin/wisp1 pathway.

CONCLUSION

Variants of sCD146, and in particular the novel I5-13-sCD146 splice variant, could thus constitute novel biomarkers and/or molecular targets for the diagnosis and treatment of SSc, but also of other angiogenesis- or fibrosis-related pathologies.

Basement Membrane Extracellular Matrix Proteins in Pulmonary Vascular and Right Ventricular Remodeling in Pulmonary Hypertension

The extracellular matrix (ECM), a highly organized network of structural and nonstructural proteins, plays a pivotal role in cellular and tissue homeostasis. Changes in the ECM are critical for normal tissue repair, whereas dysregulation contributes to aberrant tissue remodeling. Pulmonary arterial hypertension is a severe disorder of the pulmonary vasculature characterized by pathologic remodeling of the pulmonary vasculature and right ventricle, increased production and deposition of structural and nonstructural proteins, and altered expression of ECM growth factors and proteases. Furthermore, ECM remodeling plays a significant role in disease progression, as several dynamic changes in its composition, quantity, and organization are documented in both humans and animal models of disease. These ECM changes impact vascular cell biology and affect proliferation of resident cells. Furthermore, ECM components determine the tissue architecture of the pulmonary and myocardial vasculature as well as the myocardium itself and provide mechanical stability crucial for tissue homeostasis. However, little is known about the basement membrane (BM), a specialized, self-assembled conglomerate of ECM proteins, during remodeling. In the vasculature, the BM is in close physical association with the vascular endothelium and smooth muscle cells. While in the myocardium, each cardiomyocyte is enclosed by a BM that serves as the interface between cardiomyocytes and the surrounding interstitial matrix. In this review, we provide a brief overview on the current state of knowledge of the BM and its ECM composition and their impact on pulmonary vascular remodeling and right ventricle dysfunction and failure in pulmonary arterial hypertension.

Epigenetic down-regulation of microRNA-126 in scleroderma endothelial cells is associated with impaired responses to VEGF and defective angiogenesis

Impaired angiogenesis in scleroderma (SSc) is a critical component of SSc pathology. MicroRNA‐126 (miR‐126) is expressed in endothelial cells (MVECs) where it regulates VEGF responses by repressing the negative regulators of VEGF, including the sprouty‐related protein‐1 (SPRED1), and phosphoinositide‐3 kinase regulatory subunit 2 (PIK3R2). MVECs were isolated from SSc skin and matched subjects (n = 6). MiR‐126 expression was measured by qPCR and in situ hybridization. Matrigel‐based tube assembly was used to test angiogenesis. MiR‐126 expression was inhibited by hsa‐miR‐126 inhibitor and enhanced by hsa‐miR‐126 Mimic. Epigenetic regulation of miR‐126 expression was examined by the addition of epigenetic inhibitors (Aza and TSA) to MVECs and by bisulphite genomic sequencing of DNA methylation of the miR‐126 promoter region. MiR‐126 expression, as well as EGFL7 (miR‐126 host gene), in SSc‐MVECs and skin, was significantly down‐regulated in association with increased expression of SPRED1 and PIK3R2 and diminished response to VEGF. Inhibition of miR‐126 in NL‐MVECs resulted in reduced angiogenic capacity, whereas overexpression of miR‐126 in SSc‐MVECs resulted in enhanced tube assembly. Addition of Aza and TSA normalized miR‐126 and EGFL7 expression levels in SSc‐MVECs. Heavy methylation in miR‐126/EGFL7 gene was noted. In conclusion, these results demonstrate that the down‐regulation of miR‐126 results in impaired VEGF responses.

Association of Circulating Vascular Endothelial Growth Factor Levels With Autoimmune Diseases: A Systematic Review and Meta-Analysis

Background

Autoimmune diseases (ADs) are characterized by immune-mediated tissue damage, in which angiogenesis is a prominent pathogenic mechanism. Vascular endothelial growth factor (VEGF), an angiogenesis modulator, is significantly elevated in several ADs including rheumatoid arthritis (RA), systemic sclerosis (SSc), and systemic lupus erythematosus (SLE). We determined whether circulating VEGF levels were associated with ADs based on pooled evidence.

Methods

The analyses included 165 studies from the PubMed, EMBASE, Cochrane Library, and Web of Science databases and fulfilled the study criteria. Comparisons of circulating VEGF levels between patients with ADs and healthy controls were performed by determining pooled standard mean differences (SMDs) with 95% confidence intervals (CIs) in a random-effect model using STATA 16.0. Subgroup, sensitivity, and meta-regression analyses were performed to determine heterogeneity and to test robustness.

Results

Compared with healthy subjects, circulating VEGF levels were significantly higher in patients with SLE (SMD 0.84, 95% CI 0.25-1.44, P = 0.0056), RA (SMD 1.48, 95% CI 0.82-2.15, P <0.0001), SSc (SMD 0.56, 95% CI 0.36-0.75, P <0.0001), Behcet's disease (SMD 1.65, 95% CI 0.88-2.41, P <0.0001), Kawasaki disease (SMD 2.41, 95% CI 0.10-4.72, P = 0.0406), ankylosing spondylitis (SMD 0.78, 95% CI 0.23-1.33, P = 0.0052), inflammatory bowel disease (SMD 0.57, 95% CI 0.43-0.71, P <0.0001), psoriasis (SMD 0.98, 95% CI 0.62-1.34, P <0.0001), and Graves' disease (SMD 0.69, 95% CI 0.20-1.19, P = 0.0056). Circulating VEGF levels correlated with disease activity and hematological parameters in ADs.

Conclusion

Circulating VEGF levels were associated with ADs and could predict disease manifestations, severity and activity in patients with ADs.

Systematic Review Registration

PROSPERO, identifier CRD42021227843.

Engineering Advanced In Vitro Models of Systemic Sclerosis for Drug Discovery and Development

Systemic sclerosis (SSc) is a complex multisystem disease with the highest case-specific mortality among all autoimmune rheumatic diseases, yet without any available curative therapy. Therefore, the development of novel therapeutic antifibrotic strategies that effectively decrease skin and organ fibrosis is needed. Existing animal models are cost-intensive, laborious and do not recapitulate the full spectrum of the disease and thus commonly fail to predict human efficacy. Advanced in vitro models, which closely mimic critical aspects of the pathology, have emerged as valuable platforms to investigate novel pharmaceutical therapies for the treatment of SSc. This review focuses on recent advancements in the development of SSc in vitro models, sheds light onto biological (e.g., growth factors, cytokines, coculture systems), biochemical (e.g., hypoxia, reactive oxygen species) and biophysical (e.g., stiffness, topography, dimensionality) cues that have been utilized for the in vitro recapitulation of the SSc microenvironment, and highlights future perspectives for effective drug discovery and validation.

Endostatin and Vascular Endothelial Growth Factor-A165b May Contribute to Classification of Pulmonary Hypertension

Background: Pulmonary hypertension (PH) is characterized by dysregulation of small pulmonary arteries. In addition to endostatin (ES), placenta growth factor (PlGF), vascular endothelial growth factor-A (VEGF-A), and the anti-angiogenesis isoform of VEGF-A (VEGF-A₁₆₅b) are associated with PH. However, the usefulness of these biomarkers in PH in unknown. We investigated whether these 4 biomarkers are related to PH classification. Methods and Results: Between July 2015 and August 2017, 33 control patients and 107 PH patients were enrolled in the study. Among the PH patients, 48 had pulmonary arterial hypertension (PAH), 5 had left heart disease-associated PH (LHD-PH), 4 had lung disease-associated PH (LD-PH), and 50 had chronic thromboembolic PH (CTEPH). Among the PAH patients, 16 had idiopathic PAH (IPAH) and 17 had connective tissue disease-associated PAH (CTD-PAH). PlGF, total VEGF-A, and VEGF-A₁₆₅b levels were measured in the control and PH groups. ES was only measured in the PH group. VEGF-A₁₆₅b levels were significantly higher in the LD-PH group than in the PAH, LHD-PH, and CTEPH groups (all P<0.001). PlGF levels were significantly higher in the CTD-PAH group than in the IPAH and control groups. ES levels were significantly correlated with the 6-min walk distance (P<0.001), B-type natriuretic peptide (P<0.001), and pulmonary vascular resistance (P=0.008). Conclusions: ES could detect CTD-PAH in PAH and may be an indicator of PH severity. VEGF-A₁₆₅b was useful in detecting LD-PH.

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.

The Utility of Plasma Vascular Biomarkers in Systemic Sclerosis: A Prospective Longitudinal Analysis

OBJECTIVE

In cross-sectional studies, pulmonary hypertension (PH) and ischemic digital lesions are 2 scleroderma vascular outcomes associated with abnormalities in biomarkers of angiogenesis. The clinical usefulness of these biomarkers is unknown, in part due to lack of data on longitudinal measurement. This prospective longitudinal study was undertaken to evaluate vascular biomarker measurements in patients with systemic sclerosis (SSc) over time.

METHODS

We conducted a prospective cohort study of 300 patients with SSc who were followed up for at least a 5-year period and lacked evidence of PH and/or active ischemic digital lesions at enrollment. Levels of hepatocyte growth factor (HGF), soluble Flt-1 (sFlt-1), soluble endoglin, endostatin, and placental growth factor (PLGF) were obtained at multiple time points and assessed for their ability to predict the development of PH/ischemic digital lesions. Hazard ratios (HRs) with 95% confidence intervals (95% CIs) were calculated.

RESULTS

Forty-six patients (15%) developed PH and 69 patients (23%) developed an ischemic digital lesion. In time-to-event analyses, the following 3 biomarkers measured at cohort entry were found to be significantly associated with the development of PH: HGF (HR 1.99 [95% CI 1.24-3.17], P = 0.004), sFlt-1 (HR 3.04 [95% CI 1.29-7.14], P = 0.011), and PLGF (HR 2.74 [95% CI 1.32-5.69], P = 0.007). As time approaching PH diagnosis decreased, there was no corresponding increase in any biomarker level. Upon converting each continuous vascular biomarker into a binary variable, a dose-response relationship was observed for the number of elevated biomarkers at cohort entry and the risk of developing PH. With each additional elevated biomarker at cohort entry, there was a 78% increase in the risk of developing PH (HR 1.78 [95% CI 1.2-2.6], P = 0.004).

CONCLUSION

These data suggest that molecules involved in angiogenesis reflect vascular perturbation, and that elevations in these biomarkers at first encounter can indicate patients who are at risk of PH development.

Vascular biomarkers and digital ulcerations in systemic sclerosis: results from a randomized controlled trial of oral treprostinil (DISTOL-1)

INTRODUCTION

Although there is abundant evidence of vascular perturbation from studies of peripheral blood in systemic sclerosis (SSc), there are few data about the ability to use biomarkers of vascular injury and growth factors to predict vascular outcomes and response to therapy. We sought to explore the association between candidate vascular biomarkers and digital ulcerations (DU) in a clinical trial context.

METHODS

We examined 19 circulating vascular, angiogenic, and inflammatory biomarkers in 124 patients with scleroderma and DU who participated in a randomized controlled trial of oral treprostinil diolamine (ClinicalTrials.gov identifier NCT00775463). Correlation, regression, and random forest analyses were conducted to assess biomarker relationships in response to drug treatment.

RESULTS

Over the 20-week trial, 82 (66%) patients had their cardinal ulcer completely heal, 54 (44%) developed new ulcers, and 72 (58%) had complete healing of all ulcers; mean change in ulcer burden comparing week 20 with baseline was - 0.36 ± 1.70. Nineteen biomarkers were analyzed for their association and ability to predict clinical DU outcomes. After adjusting for multiple comparisons, no individual biomarker (baseline level, week 20 level, or change over time) was significantly associated with any of the clinical outcomes, suggesting that traditional vascular, angiogenic or inflammatory drivers are not predictive of ulcer fate.

CONCLUSIONS

The lack of strong response to any of the vascular, angiogenic, or inflammatory markers suggest that these pathways are not primary drivers in the development of DU clinical outcomes in a SSc population with prevalent DU.

KEY POINTS

• Currently we lack robust biomarkers to predict vascular outcomes or response to therapy in scleroderma patients with Raynaud's phenomenon.• Longitudinal assessment of vascular biomarkers in a clinical trial setting provides a unique opportunity to define biomarkers that predict vascular outcomes.• In a randomized controlled trial of oral treprostinil diolamine for treatment of scleroderma-associated digital ulcers, biomarkers involved in several vascular, inflammatory, and angiogenic pathways did not predict short-term clinical response to therapy or digital ulcer outcomes.• Further study of these and other biomarkers should be considered in Raynaud's clinical trials in scleroderma patients without prevalent digital ulcers.

Up-regulation of IGF-1, RANTES and VEGF in patients with anti-centromere antibody-positive early/mild systemic sclerosis

OBJECTIVE

Multiple cytokine network may control the pathogenesis of vasculopathy in patients with systemic sclerosis (SSc). We aimed at comparing angiogenic cytokine profile among SSc patients at various clinical stage.

METHODS

We divided nine patients with anti-centromere antibody (ACA) who were suspected of SSc and diagnosed as having SSc into three groups (group1: pre-clinical stage of SSc, group2: mild/early SSc and group3: typical lcSSc) according to the ACR/EULAR2013 classification criteria or ACR1980 preliminary classification, and serum sample were obtained from them. We evaluated the expression levels of 20 cytokines by membrane array.

RESULTS

Average values of EGF, ENA-78, bFGF, IGF-I, IL-8, MCP-1, TGF-β1, thrombopoietin, VEGF and VEGF-D in group2 were increased compared as those of group1 more than twofold. Statistically significant difference was found in serum levels of IGF-1, RANTES and VEGF between group1 and group2. There was also significant difference in the value of VEGF between group1 and group3. There were mild and significant correlations between serum IGF-1 and RANTES levels (r = 0.721, p = .028).

CONCLUSION

IGF-1, RANTES and VEGF are thought to be involved in the disease development from pre-clinical stage of SSc to early/mild SSc. Thus, these cytokines may be utilized as a biomarker for early diagnosis.

Proposition of a novel animal model of systemic sclerosis induced by type V collagen in C57BL/6 mice that reproduces fibrosis, vasculopathy and autoimmunity

BACKGROUND

Type V collagen (Col V) has the potential to become an autoantigen and has been associated with the pathogenesis of systemic sclerosis (SSc). We characterized serological, functional, and histopathological features of the skin and lung in a novel SSc murine model induced by Col V immunization.

METHODS

Female C57BL/6 mice (n = 19, IMU-COLV) were subcutaneously immunized with two doses of Col V (125 μg) emulsified in complete Freund adjuvant, followed by two intramuscular boosters. The control group (n = 19) did not receive Col V. After 120 days, we examined the respiratory mechanics, serum autoantibodies, and vascular manifestations of the mice. The skin and lung inflammatory processes and the collagen gene/protein expressions were analyzed.

RESULTS

Vascular manifestations were characterized by endothelial cell activity and apoptosis, as shown by the increased expression of VEGF, endothelin-1, and caspase-3 in endothelial cells. The IMU-COLV mice presented with increased tissue elastance and a nonspecific interstitial pneumonia (NSIP) histologic pattern in the lung, combined with the thickening of the small and medium intrapulmonary arteries, increased Col V fibers, and increased COL1A1, COL1A2, COL3A1, COL5A1, and COL5A2 gene expression. The skin of the IMU-COLV mice showed thickness, epidermal rectification, decreased papillary dermis, atrophied appendages, and increased collagen, COL5A1, and COL5A2 gene expression. Anti-collagen III and IV and ANA antibodies were detected in the sera of the IMU-COLV mice.

CONCLUSION

We demonstrated that cutaneous, vascular, and pulmonary remodeling are mimicked in the Col V-induced SSc mouse model, which thus represents a suitable preclinical model to study the mechanisms and therapeutic approaches for SSc.

Hot topics in the mechanisms of pulmonary arterial hypertension disease: cancer-like pathobiology, the role of the adventitia, systemic involvement, and right ventricular failure

In order to intervene appropriately and develop disease-modifying therapeutics for pulmonary arterial hypertension, it is crucial to understand the mechanisms of disease pathogenesis and progression. We herein discuss four topics of disease mechanisms that are currently highly debated, yet still unsolved, in the field of pulmonary arterial hypertension. Is pulmonary arterial hypertension a cancer-like disease? Does the adventitia play an important role in the initiation of pulmonary vascular remodeling? Is pulmonary arterial hypertension a systemic disease? Does capillary loss drive right ventricular failure? While pulmonary arterial hypertension does not replicate all features of cancer, anti-proliferative cancer therapeutics might still be beneficial in pulmonary arterial hypertension if monitored for safety and tolerability. It was recognized that the adventitia as a cell-rich compartment is important in the disease pathogenesis of pulmonary arterial hypertension and should be a therapeutic target, albeit the data are inconclusive as to whether the adventitia is involved in the initiation of neointima formation. There was agreement that systemic diseases can lead to pulmonary arterial hypertension and that pulmonary arterial hypertension can have systemic effects related to the advanced lung pathology, yet there was less agreement on whether idiopathic pulmonary arterial hypertension is a systemic disease per se. Despite acknowledging the limitations of exactly assessing vascular density in the right ventricle, it was recognized that the failing right ventricle may show inadequate vascular adaptation resulting in inadequate delivery of oxygen and other metabolites. Although the debate was not meant to result in a definite resolution of the specific arguments, it sparked ideas about how we might resolve the discrepancies by improving our disease modeling (rodent models, large-animal studies, studies of human cells, tissues, and organs) as well as standardization of the models. Novel experimental approaches, such as lineage tracing and better three-dimensional imaging of experimental as well as human lung and heart tissues, might unravel how different cells contribute to the disease pathology.

Microvascular involvement in systemic sclerosis and systemic lupus erythematosus

Microvascular changes play central roles in the pathophysiology of SSc and SLE, and represent major causes of morbidity and mortality in these patients. Therefore, clinical tools that can assess the microvasculature are of great importance both at the time of diagnosis and follow-up of these cases. These tools include capillaroscopy, laser imaging techniques, infrared thermography, and iontophoresis. In this review, we examined the clinical manifestations and pathobiology of microvascular involvement in SSc and SLE as well as the methodologies used to evaluate the microvasculature.

Emerging Roles of Redox-Mediated Angiogenesis and Oxidative Stress in Dermatoses

Angiogenesis is the process of new vessel formation, which sprouts from preexisting vessels. This process is highly complex and primarily involves several key steps, including stimulation of endothelial cells by growth factors, degradation of the extracellular matrix by proteolytic enzymes, migration and proliferation of endothelial cells, and capillary tube formation. Currently, it is considered that multiple cytokines play a vital role in this process, which consist of proangiogenic factors (e.g., vascular endothelial growth factor, fibroblast growth factors, and angiopoietins) and antiangiogenic factors (e.g., endostatin, thrombospondin, and angiostatin). Angiogenesis is essential for most physiological events, such as body growth and development, tissue repair, and wound healing. However, uncontrolled neovascularization may contribute to angiogenic disorders. In physiological conditions, the above promoters and inhibitors function in a coordinated way to induce and sustain angiogenesis within a limited period of time. Conversely, the imbalance between proangiogenic and antiangiogenic factors could cause pathological angiogenesis and trigger several diseases. With insights into the molecular mechanisms of angiogenesis, increasing reports have shown that a close relationship exists between angiogenesis and oxidative stress (OS) in both physiological and pathological conditions. OS, an imbalance between prooxidant and antioxidant systems, is a cause and consequence of many vascular complains and serves as one of the biomarkers for these diseases. Furthermore, emerging evidence supports that OS and angiogenesis play vital roles in many dermatoses, such as psoriasis, atopic dermatitis, and skin tumor. This review summarizes recent findings on the role of OS as a trigger of angiogenesis in skin disorders, highlights newly identified mechanisms, and introduces the antiangiogenic and antioxidant therapeutic strategies.

Recent advances in understanding lymphangiogenesis and metabolism

The blood and lymphatic vasculatures are vital to the maintenance of homeostasis. The interaction between two vascular networks throughout the body is precisely controlled to enable oxygen and nutrient delivery, removal of carbon dioxide and metabolic waste, drainage of interstitial fluid, transport of immune cells, and other key activities. Recent years have seen an explosion of information dealing with the development and function of the lymphatic system. The growth of lymphatic vessels, termed lymphangiogenesis, is a high-energy requirement process that involves sprouting, proliferation, migration, and remodeling of lymphatic endothelial cells and capillaries. Although there has been substantial progress in identifying growth factors and their downstream signaling pathways that control lymphangiogenesis, the role of metabolic processes during lymphangiogenesis and their links to growth factor signaling are poorly understood. In this review, we will discuss recent work that has provided new insights into lymphatic metabolism and its role in lymphangiogenesis.

Serum level of endostatin and digital ulcers in systemic sclerosis patients

Patients with systemic sclerosis (SSc) are at a high risk of the development of ischaemic digital ulcers (DUs) that can be complicated with infections, gangrene, and osteomyelitis. The aim of this study is to evaluate the role of endostatin in scleroderma DUs.In total, 90 SSc patients were enrolled in this study. Serum endostatin levels and DU assessment were determined in all SSc patients. The serum levels of endostatin significantly increased with progression of capillaroscopic damage (P < .01). The serum levels of endostatin are significantly (P < .05) higher in SSc patients with new DUs than in SSc patients without new DUs (127 ± 31.1 ng/mL vs 116.3 ± 39.7 ng/mL). The Receiver Operating Characteristic (ROC) curves demonstrated good accuracy of new DU prediction for the serum level of endostatin (0.70, P < .01 [95% confidence interval (CI) 0.59-0.81]). Using a cut-off value of 116 ng/mL, the odds ratio was 2.609 (CI 1.075-6.330, P < .05). The serum levels of endostatin are significantly (P < .01) higher in SSc patients with infected DUs than in SSc patients without infected DUs (139.2 [114.6-340.91] ng/mL vs 117.5 [64.3-163.9] ng/mL). Serum levels of endostatin are higher in patients with DUs, especially in those with infected DUs.

Antisense Long Non-Coding RNAs Are Deregulated in Skin Tissue of Patients with Systemic Sclerosis

Systemic sclerosis is an autoimmune disease characterized by fibrosis of skin and multiple organs of which the pathogenesis is poorly understood. We studied differentially expressed coding and non-coding genes in relation to systemic sclerosis pathogenesis with a specific focus on antisense non-coding RNAs. Skin biopsy-derived RNAs from 14 early systemic sclerosis patients and six healthy individuals were sequenced with ion-torrent and analyzed using DEseq2. Overall, 4,901 genes with a fold change >1.5 and a false discovery rate <5% were detected in patients versus controls. Upregulated genes clustered in immunologic, cell adhesion, and keratin-related processes. Interestingly, 676 deregulated non-coding genes were detected, 257 of which were classified as antisense genes. Sense genes expressed opposite of these antisense genes were also deregulated in 42% of the observed sense-antisense gene pairs. The majority of the antisense genes had a similar effect sizes in an independent North American dataset with three genes (CTBP1-AS2, OTUD6B-AS1, and AGAP2-AS1) exceeding the study-wide Bonferroni-corrected P-value (P_Bonf < 0.0023, P_combined = 1.1 × 10^-9, 1.4 × 10^-8, 1.7 × 10^-6, respectively). In this study, we highlight that together with coding genes, (antisense) long non-coding RNAs are deregulated in skin tissue of systemic sclerosis patients suggesting a novel class of genes involved in pathogenesis of systemic sclerosis.

PDGF in organ fibrosis

Fibrosis is part of a tissue repair response to injury, defined as increased deposition of extracellular matrix. In some instances, fibrosis is beneficial; however, in the majority of diseases fibrosis is detrimental. Virtually all chronic progressive diseases are associated with fibrosis, representing a huge number of patients worldwide. Fibrosis occurs in all organs and tissues, becomes irreversible with time and further drives loss of tissue function. Various cells types initiate and perpetuate pathological fibrosis by paracrine activation of the principal cellular executors of fibrosis, i.e. stromal mesenchymal cells like fibroblasts, pericytes and myofibroblasts. Multiple pathways are involved in fibrosis, platelet-derived growth factor (PDGF)-signaling being one of the central mediators. Stromal mesenchymal cells express both PDGF receptors (PDGFR) α and β, activation of which drives proliferation, migration and production of extracellular matrix, i.e. the principal processes of fibrosis. Here, we review the role of PDGF signaling in organ fibrosis, with particular focus on the more recently described ligands PDGF-C and -D. We discuss the potential challenges, opportunities and open questions in using PDGF as a potential target for anti-fibrotic therapies.

Measurement of Serum Klotho in Systemic Sclerosis

Background

The aim of our study was to evaluate the serum concentration of klotho in a cohort of systemic sclerosis (SSc) patients compared to that of healthy controls and to correlate its levels with the degree and the kind of organ involvement.

Methods

Blood samples obtained from both patients and controls were collected and analysed by an ELISA test for the determination of human soluble klotho. Scleroderma patients were evaluated for disease activity through clinical, laboratory, and instrumental assessment.

Results

Our cohort consisted of 81 SSc patients (74 females, mean age 63.9 ± 13.1 years) and 136 healthy controls (78 females, mean age 50.5 ± 10.7 years). When matched for age, serum klotho concentration significantly differed between controls and patients (p < 0.001). However, in SSc patients, we did not find any significant association between serum klotho and clinical, laboratory, and instrumental findings. Lower serum levels of klotho were detected in 4 patients who were anticitrullinated peptide antibody (ACPA) positive (p = 0.005).

Conclusions

Our data show a lower concentration of klotho in the serum of SSc patients compared to that of healthy controls, without any significant association with clinical manifestations and laboratory and instrumental findings. The association between serum klotho and ACPA positivity requires further investigation.

Angiogenic T cell expansion correlates with severity of peripheral vascular damage in systemic sclerosis

The mechanisms underlying endothelial cell injury and defective vascular repair in systemic sclerosis (SSc) remain unclear. Since the recently discovered angiogenic T cells (Tang) may have an important role in the repair of damaged endothelium, this study aimed to analyze the Tang population in relation to disease-related peripheral vascular features in SSc patients. Tang (CD3⁺CD31⁺CXCR4⁺) were quantified by flow cytometry in peripheral blood samples from 39 SSc patients and 18 healthy controls (HC). Circulating levels of the CXCR4 ligand stromal cell-derived factor (SDF)-1α and proangiogenic factors were assessed in paired serum samples by immunoassay. Serial skin sections from SSc patients and HC were subjected to CD3/CD31 and CD3/CXCR4 double immunofluorescence. Circulating Tang were significantly increased in SSc patients with digital ulcers (DU) compared either with SSc patients without DU or with HC. Tang levels were significantly higher in SSc patients with late nailfold videocapillaroscopy (NVC) pattern than in those with early/active NVC patterns and in HC. No difference in circulating Tang was found when comparing either SSc patients without DU or patients with early/active NVC patterns and HC. In SSc peripheral blood, Tang percentage was inversely correlated to levels of SDF-1α and CD34⁺CD133⁺VEGFR-2⁺ endothelial progenitor cells (EPC), and positively correlated to levels of vascular endothelial growth factor and matrix metalloproteinase-9. Tang were frequently detected in SSc dermal perivascular inflammatory infiltrates. In summary, our findings demonstrate for the first time that Tang cells are selectively expanded in the circulation of SSc patients displaying severe peripheral vascular complications like DU. In SSc, Tang may represent a potentially useful biomarker reflecting peripheral vascular damage severity. Tang expansion may be an ineffective attempt to compensate the need for increased angiogenesis and EPC function. Further studies are required to clarify the function of Tang cells and investigate the mechanisms responsible for their change in SSc.

Angiogenic and angiostatic factors in renal scleroderma-associated vasculopathy

BACKGROUND

The angiogenesis in systemic sclerosis (SSc) is impaired. An imbalance of pro-angiogenic factors and angiogenesis inhibitors has been implicated in the progression of peripheral microvascular damage, defective vascular repair and fibrosis. Intrarenal resistance index are considered markers of renal vasculopathy. The aim of the study is to evaluate angiogenic and angiostatic factors (VEGF and endostatin) in SSc patients and to correlate with intrarenal hemodynamic parameters.

METHODS

91 SSc patients were enrolled in this study. Serum VEGF and endostatin levels were determined. All patients underwent a renal Doppler ultrasound RESULTS: A significant positive correlation was observed between endostatin and renal Doppler parameters (p<0.0001). A negative correlation was observed between serum levels of endostatin and eGFR (p<0.01). In SSc patients with high resistive index, serum levels of endostatin were significantly (p<0.01) higher than in SSc patients with normal resistive index. The serum levels of endostatin significantly increased with progression of nailfold videocapillaroscopy damage (p<0.01) and were significantly (p<0.05) higher in SSc patients with digital ulcers than in SSc patients without digital ulcers.

CONCLUSION

This is the first study that assess in SSc patients intrarenal hemodynamic parameters and endostatin. In SSc patients, endostatin represents a marker of renal scleroderma-associated vasculopathy.

The role of endothelial cells in the vasculopathy of systemic sclerosis: A systematic review

INTRODUCTION

Systemic sclerosis (SSc) is an autoimmune connective tissue disorder characterized by fibroproliferative vasculopathy, immunological abnormalities and progressive fibrosis of multiple organs including the skin. In this study, all English speaking articles concerning the role of endothelial cells (ECs) in SSc vasculopathy and representing biomarkers are systematically reviewed and categorized according to endothelial cell (EC) (dys)function in SSc.

METHODS

A sensitive search on behalf of the EULAR study group on microcirculation in Rheumatic Diseases was developed in Pubmed, The Cochrane Library and Web of Science to identify articles on SSc vasculopathy and the role of ECs using the following Mesh terms: (systemic sclerosis OR scleroderma) AND pathogenesis AND (endothelial cells OR marker). All selected papers were read and discussed by two independent reviewers. The selection process was based on title, abstract and full text level. Additionally, both reviewers further searched the reference lists of the articles selected for reading on full text level for supplementary papers. These additional articles went through the same selection process.

RESULTS

In total 193 resulting articles were selected and the identified biomarkers were categorized according to description of EC (dys)function in SSc. The most representing and reliable biomarkers described by the selected articles were adhesion molecules for EC activation, anti-endothelial cell antibodies for EC apoptosis, vascular endothelial growth factor (VEGF), its receptor VEGFR-2 and endostatin for disturbed angiogenesis, endothelial progenitors cells for defective vasculogenesis, endothelin-1 for disturbed vascular tone control, Von Willebrand factor for coagulopathy and interleukin (IL)-33 for EC-immune system communication. Emerging, relatively new discovered biomarkers described in the selected articles, are VEGF₁₆₅b, IL-17A and the adipocytokines. Finally, myofibroblasts involved in tissue fibrosis in SSc can derive from ECs or epithelial cells through a process known as endothelial-to-mesenchymal transition.

CONCLUSION

This systematic review emphasizes the growing evidence that SSc is primarily a vascular disease where EC dysfunction is present and prominent in different aspects of cell survival (activation and apoptosis), angiogenesis and vasculogenesis and where disturbed interactions between ECs and various other cells contribute to SSc vasculopathy.

Differential expression of hepatocyte growth factor in patients with systemic sclerosis-associated pulmonary arterial hypertension

Introduction

Non-invasive biomarkers are needed to identify pulmonary arterial hypertension (PAH) in systemic sclerosis (SSc) patients who may benefit from early intervention. We sought to identify novel cytokines that differentiate patients with incident SSc-PAH from those at high risk for PAH.

Methods

The Pulmonary Hypertension Assessment and Recognition of Outcomes in Scleroderma (PHAROS) Registry is a multicenter registry of SSc patients at high risk for PAH (at-risk) or with incident right-heart catheterization-confirmed PAH (definite PAH). Serum from 10 at-risk and 9 definite PAH patients were profiled with Bio-PlexTM bead arrays for 48 cytokines and chemokines. We also evaluated the longitudinal change in cytokine profiles from 3 at-risk patients who subsequently developed definite PAH.

Results

Clinical features of at-risk versus definite PAH patients were not significantly different except for right-ventricular systolic pressure on echocardiogram (34 ± 7 vs. 45 ± 8 mmHg, p = 0.006), left atrial diameter (2.9 ± 0.5 vs. 3.7 ± 0.4 cm, p = 0.02), 6-minute walk distance (508 ± 115 vs. 393 ± 70 m, p = 0.02), mean pulmonary artery pressure (18 ± 4 vs. 32 ± 6 mmHg, p = 0.01), and pulmonary vascular resistance (111 ± 48 vs. 272 ± 109 dyn/s/cm5, p = 0.009). Serum cytokine profiling identified hepatocyte growth factor (HGF) as the only cytokine significantly different between the at-risk and definite PAH groups (225.8 ± 55.0 vs. 361.6 ± 164.5 pg/mL, q<0.1%). Profiling of longitudinal samples of at-risk to definite PAH patients did not identify any significant changes in HGF or other cytokines over time.

Conclusions

Definite PAH patients expressed higher levels of HGF than at-risk patients. Further studies are needed to clarify the utility of HGF as a predictive biomarker for SSc-PAH.

Biomarkers in systemic sclerosis: Their potential to predict clinical courses

The concept of a biomarker was defined as "a characteristic marker that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention" by the National Institutes of Health Biomarkers Definitions Working group in 2001. Clinical features, disease progress, therapeutic response and prognosis are heterogeneous among patients with systemic sclerosis (SSc). Therefore, biomarkers that can predict these matters are required for the progress of clinical practice. At present, SSc-specific autoantibodies are the most useful biomarkers for diagnosis and predicting clinical features. Otherwise, biomarkers specific only for SSc have not been identified yet. The glycoprotein krebs von den Lungen-6, surfactant protein-D and CCL18 are promising serum biomarkers of SSc-related interstitial lung diseases. Serum/plasma levels of brain natriuretic peptide and serum N-terminal pro-brain natriuretic peptide have been used as biomarkers for SSc-related pulmonary arterial hypertension. Other potential serum/plasma biomarkers for fibrosis and vascular involvement of SSc are connective tissue growth factor, interleukin-6, CCL2, CXCL4, intercellular adhesion molecule (ICAM)-1, P-selectin, vascular endothelial growth factor, von Willebrand factor, endostatin, endoglin and endothelin-1. In our multicenter prospective studies of Japanese early SSc, serum ICAM-1 levels were predictive for subsequent respiratory dysfunction and serum levels of CXCL8 and P-selectin were predictive for subsequent physical disability. Further large, multicenter, prospective, longitudinal studies will be needed to identify and validate critical biomarkers of SSc.

Anti-Ephrin Type-B Receptor 2 (EphB2) and Anti-Three Prime Histone mRNA EXonuclease 1 (THEX1) Autoantibodies in Scleroderma and Lupus

In a pilot ProtoArray analysis, we identified 6 proteins out of 9483 recognized by autoantibodies (AAb) from patients with systemic sclerosis (SSc). We further investigated the 6 candidates by ELISA on hundreds of controls and patients, including patients with Systemic Lupus Erythematosus (SLE), known for high sera reactivity and overlapping AAb with SSc. Only 2 of the 6 candidates, Ephrin type-B receptor 2 (EphB2) and Three prime Histone mRNA EXonuclease 1 (THEX1), remained significantly recognized by sera samples from SSc compared to controls (healthy or with rheumatic diseases) with, respectively, 34% versus 14% (P = 2.10⁻⁴) and 60% versus 28% (P = 3.10⁻⁸). Above all, EphB2 and THEX1 revealed to be mainly recognized by SLE sera samples with respectively 56%, (P = 2.10⁻¹⁰) and 82% (P = 5.10⁻¹³). As anti-EphB2 and anti-THEX1 AAb were found in both diseases, an epitope mapping was realized on each protein to refine SSc and SLE diagnosis. A 15-mer peptide from EphB2 allowed to identify 35% of SLE sera samples (N = 48) versus only 5% of any other sera samples (N = 157), including SSc sera samples. AAb titers were significantly higher in SLE sera (P<0.0001) and correlated with disease activity (p<0.02). We could not find an epitope on EphB2 protein for SSc neither on THEX1 for SSc or SLE. We showed that patients with SSc or SLE have AAb against EphB2, a protein involved in angiogenesis, and THEX1, a 3’-5’ exoribonuclease involved in histone mRNA degradation. We have further identified a peptide from EphB2 as a specific and sensitive tool for SLE diagnosis.

Indocyanine green angiographic evidence of choroiditis in scleroderma

PURPOSE

The purpose of this case report was to demonstrate evidence of indocyanine green angiography leakage consistent with choroiditis in a patient with scleroderma.

METHODS

In this case report, the patient underwent a variety of tests and examinations, including systemic evaluation, full ocular examination, skin biopsy, indocyanine green, and fluorescein angiography testing. A 52-year-old man had blurred vision centrally in both eyes. Vision was 20/25 and 20/20. Posterior examination showed cotton-wool spots in both eyes. The patient met European League against Rheumatism (EULAR) criteria for scleroderma.

RESULTS

Fluorescein angiography confirmed the presence of leakage from the retinal vessels. More importantly, indocyanine green angiography revealed choroidal vessel leakage in both eyes. This provided evidence of choroiditis before vessel obliteration. Previous studies have shown evidence of choriocapillaris obliteration. Choroidal vessel leakage, however, has not been reported in patients with scleroderma.

CONCLUSION

The results of this case demonstrate the usefulness of indocyanine green angiography in detecting the presence of choroiditis in scleroderma.

[Large vessels vasculopathy in systemic sclerosis]

Vasculopathy in systemic sclerosis is a severe, in many cases irreversible, manifestation that can lead to amputation. While the classical clinical manifestations of the disease have to do with the involvement of microcirculation, proximal vessels of upper and lower limbs can also be affected. This involvement of large vessels may be related to systemic sclerosis, vasculitis or atherosclerotic, and the differential diagnosis is not easy. To conduct a proper and early diagnosis, it is essential to start prompt appropriate treatment. In this review, we examine the involvement of large vessels in scleroderma, an understudied manifestation with important prognostic and therapeutic implications.

The Circulating Levels of Selenium, Zinc, Midkine, Some Inflammatory Cytokines, and Angiogenic Factors in Mitral Chordae Tendineae Rupture

Chordae tendineae rupture process is associated with increased production of inflammatory and angiogenesis mediators in connective tissues, which contributes to chronic inflammation and pathogenesis of degenerative chordae. A few trace elements are known to possess antioxidant, anti-inflammatory, and antiangiogenic properties. Therefore, the aim of this study was to determine whether zinc, selenium, midkine (MK), interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-alpha (TNF-α), vascular endothelial growth factor-A (VEGF-A), platelet-derived growth factor-BB (PDGF-BB), and reduced glutathione (GSH) levels are associated with inflammation and angiogenesis processes in the context of a potential etiology causing aggravation of mitral regurgitation and/or ruptured chordae tendineae. Seventy-one subjects comprising 34 patients with mitral chordae tendineae rupture (MCTR) and 37 healthy controls diagnosed on the basis of their clinical profile and transthoracic echocardiography were included in this study. The levels of GSH, MK, selenium, and zinc were found to be lower in the patients group when compared to control group. There were no significant difference in plasma TNF-α, IL-1β, IL-6, IL-8, VEGF-A, and PDGF-BB levels between two groups. There were positive significant correlations between MK and GSH, MK, and selenium levels in patients with MCTR. According to our data in which selenium, zinc, MK, and GSH decreased in MCTR patients, inflammatory response, oxidative stress, and trace element levels may contribute to etiopathogenesis of mitral regurgitation and/or ruptured chordae tendineae.

Associations between circulating endostatin levels and vascular organ damage in systemic sclerosis and mixed connective tissue disease: an observational study

Introduction

Systemic sclerosis (SSc) and mixed connective tissue disease (MCTD) are chronic immune-mediated disorders complicated by vascular organ damage. The aim of this study was to examine the serum levels of the markers of neoangiogenesis: endostatin and vascular endothelial growth factor (VEGF), in our unselected cohorts of SSc and MCTD.

Methods

Sera of SSc patients (N = 298) and MCTD patients (N = 162) from two longitudinal Norwegian cohorts were included. Blood donors were included as controls (N = 100). Circulating VEGF and endostatin were analyzed by enzyme immunoassay.

Results

Mean endostatin levels were increased in SSc patients 93.7 (37) ng/ml (P < .001) and MCTD patients 83.2 (25) ng/ml (P < .001) compared to controls 65.1 (12) ng/ml. Median VEGF levels were elevated in SSc patients 209.0 (202) pg/ml compared to MCTD patients 181.3 (175) pg/ml (P = .017) and controls 150.0 (145) pg/ml (P < .001). Multivariable analysis of SSc subsets showed that pulmonary arterial hypertension (coefficient 15.7, 95 % CI: 2.2–29.2, P = .023) and scleroderma renal crisis (coefficient 77.6, 95 % CI: 59.3–100.0, P < .001) were associated with elevated endostatin levels. Multivariable analyses of MCTD subsets showed that digital ulcers were associated with elevated endostatin levels (coefficient 10.5, 95 % CI: 3.2–17.8, P = .005). The risk of death increased by 1.6 per SD endostatin increase (95 % CI: 1.2–2.1, P = .001) in the SSc cohort and by 1.6 per SD endostatin increase (95 % CI: 1.0–2.4, P = .041) in the MCTD cohort after adjustments to known risk factors.

Conclusions

Endostatin levels were elevated in patients with SSc and MCTD, particularly SSc patients with pulmonary arterial hypertension and scleroderma renal crisis, and MCTD patients with digital ulcers. Elevated endostatin levels were also associated with increased all-cause mortality during follow-up in both groups of patients. We propose that endostatin might indicate the degree of vascular injury in SSc and MCTD patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0756-5) contains supplementary material, which is available to authorized users.

Activation of the Thromboxane A2 Receptor by 8-Isoprostane Inhibits the Pro-Angiogenic Effect of Vascular Endothelial Growth Factor in Scleroderma

The pathogenesis of scleroderma (SSc) includes components of autoimmunity, vascular dysfunction, and accumulation of extracellular matrix. 8-isoprostane, an oxidized lipid created by oxidative stress, activates the thromboxane A2 receptor (TXAR) and ROCK pathway. In this study we determined whether the TXAR was activated by 8-isoprostane in SSc endothelial cells (ECs), and whether this pathway inhibited VEGF-induced angiogenesis. Elevated 8-isoprostane was observed in plasma and conditioned media from SSc patients. SSc conditioned media inhibited EC tube formation, while addition of vitamin E, by reducing 8-isoprostane, increased tube formation. VEGF did not induce angiogenesis in SSc ECs, but vitamin E or TXAR inhibition restored its effect. The expression of TXAR, RhoA, and ROCK1/2 were elevated in SSc ECs. ROCK activity and 8-isoprostane-induced ROCK activation were significantly higher in SSc ECs while VEGF had no effect. The hyper-activation of the TXAR leads to inhibition of VEGF-induced angiogenesis, as inhibition of the TXAR pathway results in blockade of 8-isoprostane induced ROCK activation and restoration of VEGF activity. These results suggest that the TXAR pathway plays a crucial role in angiogenesis and that 8-isoprostane is not just a by-product of oxidative stress, but also plays a significant role in the impaired angiogenesis that characterizes SSc.

Biomarkers of pulmonary hypertension in patients with scleroderma: a case-control study

Introduction

Significant pulmonary vascular disease is a leading cause of death in patients with scleroderma, and early detection and early medical intervention are important, as they may delay disease progression and improve survival and quality of life. Although several biomarkers have been proposed, there remains a need to define a reliable biomarker of early pulmonary vascular disease and subsequent development of pulmonary hypertension (PH). The purpose of this study was to define potential biomarkers for clinically significant pulmonary vascular disease in patients with scleroderma.

Methods

The circulating growth factors basic fibroblast growth factor, placental growth factor (PlGF), vascular endothelial growth factor (VEGF), hepatocyte growth factor, and soluble VEGF receptor 1 (sFlt-1), as well as cytokines (interleukin [IL]-1β IL-2, IL-4, IL-5, IL-8, IL-10, IL-12, IL-13, tumor necrosis factor-α, and interferon-γ), were quantified in patients with scleroderma with PH (n = 37) or without PH (n = 40). In non-parametric unadjusted analyses, we examined associations of growth factor and cytokine levels with PH. In a subset of each group, a second set of earlier samples, drawn 3.0±1.6 years earlier, were assessed to determine the changes over time.

Results

sFlt-1 (p = 0.02) and PlGF (p = 0.02) were higher in the PH than in the non-PH group. sFlt-1 (ρ = 0.3245; p = 0.01) positively correlated with right ventricular systolic pressure. Both PlGF (p = 0.03) and sFlt-1 (p = 0.04) positively correlated with the ratio of forced vital capacity to diffusing capacity for carbon monoxide (DLCO), and both inversely correlated with DLCO (p = 0.01). Both PlGF and sFlt-1 levels were stable over time in the control population.

Conclusions

Our study demonstrated clear associations between regulators of angiogenesis (sFlt-1 and PlGF) and measures of PH in scleroderma and that these growth factors are potential biomarkers for PH in patients with scleroderma. Larger longitudinal studies are required for validation of our results.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0712-4) contains supplementary material, which is available to authorized users.

Systemic Sclerosis Sera Impair Angiogenic Performance of Dermal Microvascular Endothelial Cells: Therapeutic Implications of Cyclophosphamide

In systemic sclerosis (SSc), dermal capillaries are progressively lost with consequent chronic tissue hypoxia insufficiently compensated by angiogenesis. Clinical studies reported that intravenous cyclophosphamide (CYC) may improve SSc-related peripheral microvascular damage. Recently, we showed that CYC treatment may normalize SSc sera-induced abnormalities in endothelial cell-matrix interactions. Our objective was to evaluate in vitro the effects of sera from treatment-naïve or CYC-treated SSc patients on dermal blood microvascular endothelial cell (dMVEC) angiogenesis, migration, proliferation and apoptosis. dMVECs were challenged with sera from 21 SSc patients, treatment-naïve (n = 8) or under CYC treatment (n = 13), and 8 healthy controls. Capillary morphogenesis on Geltrex matrix was significantly reduced upon challenge with sera from naïve SSc patients compared with healthy controls. When dMVECs were challenged with sera from CYC-treated SSc patients, their angiogenic capacity was comparable to that of cells treated with healthy sera. Wound healing capacity and chemotaxis in Boyden chamber were both significantly decreased in the presence either of naïve or CYC-treated SSc sera compared with healthy sera. WST-1 assay revealed that cell proliferation was significantly decreased in dMVECs challenged with sera from naïve SSc patients compared with healthy sera. Conversely, dMVEC proliferation was not impaired in the presence of sera from CYC-treated SSc patients. Accordingly, the percentage of TUNEL-positive apoptotic dMVECs was significantly higher in the presence of sera from naïve SSc patients than healthy controls, while CYC-treated SSc sera did not induce dMVEC apoptosis. Levels of the angiostatic mediators endostatin, pentraxin 3, angiostatin and matrix metalloproteinase-12 were all significantly elevated in sera from naïve SSc patients compared with sera from both healthy controls and CYC-treated SSc patients. In SSc, CYC treatment might boost angiogenesis and consequently improve peripheral microangiopathy through the normalization of the endothelial cell-matrix interactions, reduction of endothelial cell apoptosis and rebalance of dysregulated angiostatic factors.

Macro- and microvascular disease in systemic sclerosis

Vasculopathy is common in patients with connective tissue disease and can be directly implicated in the pathogenesis of the disease. Systemic sclerosis is an auto-immune multiorgan connective tissue disorder characterized by fibrosis of the skin and visceral organs and vascular disease. Micro- and macro-vessels are a direct target of the disease. In this review, we present the various clinical manifestations of the vasculopathy that can be present in SSc patients, and then discuss the various aspects of the pathophysiology of the vascular disorders.

The right ventricle in scleroderma (2013 Grover Conference Series)

Pulmonary arterial hypertension (PAH) results from severe remodeling of the distal lung vessels leading irremediably to death through right ventricular (RV) failure. PAH (Group 1 of the World Health Organization classification of pulmonary hypertension) can be idiopathic (IPAH) or associated with other disorders, such as connective tissue diseases. Prominent among the latter is systemic sclerosis (SSc), a heterogeneous disorder characterized by endothelium dysfunction, dysregulation of fibroblasts resulting in excessive collagen production, and immune abnormalities. For as-yet-unknown reasons, SSc-associated PAH (SSc-PAH) carries a significantly worse prognosis compared with any other form of PAH in Group 1, including IPAH. We have previously shown that patients with SSc-PAH have a median survival of only 3 years, compared with 8 years for IPAH, despite modern PAH therapy. Because death is principally due to RV failure, we speculated that RV adaptation to PAH differed between the two entities due to disparate pulmonary artery loading, perhaps from vessel stiffening, or intrinsic RV myocardial disease that might limit function and adaptation to high afterload. In SSc, RV function may also be impaired by inflammatory processes, excess fibrosis of the myocardium, or altered angiogenesis, which may all contribute to impaired contractile reserve exacerbating cardiopulmonary impedance mismatch. This is now suggested by recent findings from our group that demonstrate that, although pulmonary vascular load may be similar between patients with IPAH and those with SSc-PAH, the latter display reduced myocardial contractility as assessed by pressure-volume loop measurements. This review focuses on fundamental hemodynamic, structural, and functional differences in RV from patients with SSc-PAH compared with IPAH, which may account for survival discrepancies between the two populations. Possible underlying basic mechanisms are discussed.

Elevated levels of pentraxin 3 in systemic sclerosis: associations with vascular manifestations and defective vasculogenesis

OBJECTIVE

To clarify the role of pentraxin 3 (PTX3), a multifunctional pattern recognition protein that can suppress fibroblast growth factor 2 (FGF-2), in systemic sclerosis (SSc)-related vasculopathy.

METHODS

We assessed 171 SSc patients and 19 age- and sex-matched healthy control subjects. Circulating PTX3 and FGF-2 levels were measured by enzyme immunoassay, and CD34+CD133+CD309+ endothelial progenitor cells (EPCs) were counted by flow cytometry. Correlations between PTX3 and FGF-2 and the presence or future development of vascular manifestations, including digital ulcers and pulmonary arterial hypertension (PAH), were identified by univariate and multivariate analysis. The effect of PTX3 on EPC differentiation was evaluated in proangiogenic cultures of mouse bone marrow cells in combination with colony formation assay.

RESULTS

Circulating PTX3 and FGF-2 levels were significantly higher in SSc patients than in healthy control subjects. PTX3 was elevated in SSc patients who had digital ulcers or PAH, while FGF-2 was reduced in SSc patients with PAH. Multivariate analysis identified elevated PTX3 as an independent parameter associated with the presence of digital ulcers and PAH, and PTX3 levels were a useful predictor of future occurrences of digital ulcers. Reduced FGF-2 was independently associated with the presence of PAH. EPC counts were significantly lower in patients with digital ulcers or PAH and correlated negatively with circulating PTX3 concentrations. Finally, PTX3 inhibited EPC differentiation in vitro.

CONCLUSION

In SSc patients, exposure to high concentrations of PTX3 may suppress EPC-mediated vasculogenesis and promote vascular manifestations such as digital ulcers and PAH.

Semaphorin 3A: an immunoregulator in systemic sclerosis

ABSTARCT

Semaphorin 3A (sema3A) plays a regulatory role in immune responses, mainly affecting the activation of regulatory T cells. It has been found to correlate with disease activity in rheumatoid arthritis and systemic lupus erythematosus (SLE). To investigate the expression of sema3A in patients with systemic sclerosis (SSc) compared to healthy controls and SLE disease controls and to correlate it with clinical characteristics, 27 SSc patients, 42 SLE patients and 28 healthy controls were enrolled. Serum level of sema3A was measured by ELISA, and expression of sema3A on regulatory T cells was evaluated by FACS analysis. SSc patients were evaluated for demographics, clinical manifestations, routine laboratory results, nailfold videocapillaroscopy, pulmonary function tests, echocardiograms, modified Rodnan skin score, and disease activity and severity scores. Serum levels of semaphorin 3A were lower in SSc compared to healthy controls 14.38 ± 5.7 versus 27.14 ± 8.4 ng/ml, p < 0.0001 and similar to SLE 15.7 ± 4.3 ng/ml. The expression of semaphorin 3A on regulatory T cells was also lower in SSc compared to healthy controls 61.7 ± 15.7 versus 88.7 ± 3. 7 % (p < 0.0001). Semaphorin 3A serum level inversely correlated with the duration of disease: r = -0.4, p = 0.036 and with low C4 level r = 0.66, p = 0.026. SCL-70 antibody positivity was associated with a lower semaphorin 3A level (difference in mean of 3.44, p = 0.06). Sema3A expression is low in SSc serum and more specifically on regulatory T cells. This may help explain the reduced activation of regulatory T cells in SSc.