Angiogenesis and Vasculopathy in Systemic Sclerosis: Evolving Concepts

Long-term cardiovascular outcomes after percutaneous coronary intervention in patients with systemic sclerosis

Background

Recent data have shown that systemic sclerosis (SSc) is a significant risk factor for coronary artery disease (CAD) and poorer cardiovascular outcomes in the setting of acute coronary syndrome. However, the morphological characteristics of CAD and the long-term cardiovascular outcomes in patients with concurrent SSc and CAD remain unclear.

Methods

We retrospectively investigated 3,300 patients with CAD who underwent percutaneous coronary intervention (PCI) without prior myocardial infarction or coronary artery revascularization. Laboratory, echocardiographic and angiographic characteristics, and clinical outcomes were compared between patients with and without SSc according to a 1:3 propensity score-matching analysis adjusted for patient demographics and comorbidities. The primary outcome was a composite of cardiac death, myocardial infarction, and stroke, and the secondary outcome was a composite of the primary outcome and heart failure hospitalization.

Results

Among all 3,300 patients, 17 (0.5 %) had SSc. The patients were classified into an SSc group (n = 17) and non-SSc group (n = 51) by propensity score matching. There were no significant differences in laboratory or echocardiographic parameters between the two groups. However, CAD tended to be more complex in the SSc group because of the higher proportion of left main trunk lesions (p = 0.100) and higher SYNergy between PCI with TAXUS™ and Cardiac Surgery (SYNTAX) score (p = 0.030). During a median follow-up of 3.1 years, patients with SSc more frequently experienced primary and secondary outcomes than those without SSc (both log-rank p < 0.02).

Conclusions

Among patients with CAD, long-term cardiovascular outcomes after PCI were poorer in those with than without SSc.

Assessment of interocular symmetry of choroidal vascularity index and thickness in patients with systemic sclerosis: a prospective study

Purpose

Systemic sclerosis (SSc) affects blood vessels, internal organs, and skin. In ophthalmology, SSc impacts the choroid. The choroidal vascularity index (CVI) measures the vascular component of the choroid and may serve as a biomarker for the disease staging and prognosis. Studies have reported reduced choroidal thickness and altered CVI in SSc, which supports the theory of vascular damage. This study aimed to examine interocular symmetry in choroidal parameters among SSc patients. It has provided the insight into the disease symmetry and assessed the representativeness of examining one eye.

Methods

This prospective single-center cross-sectional study included 33 patients with SSc and 40 healthy controls. The patients underwent ophthalmological examination (including refraction, visual acuity, IOP, biometry, slit-lamp biomicroscopy, dilated fundus examination, and spectral-domain optical coherence tomography) and rheumatological evaluation. Various parameters of the choroid in the macular and peripapillary regions were analyzed, including choroidal thickness, choroidal volume, and CVI. The interocular asymmetry in the choroidal parameters was quantified using signed and absolute differences. The correlation analysis between the left and right eyes was based on the intraclass correlation coefficient (ICC), Spearman's correlation coefficient, and paired Wilcoxon test.

Results

There were no significant differences in the macular and peripapillary choroidal parameters between fellow eyes in both SSc patients and controls (p > 0.05). The parameter that showed the lowest correlation among those examined was CVI-in both groups, as well as in both examined areas. The interocular correlation of choroidal parameters was stronger in the peripapillary area than in the macular area in both groups. In general, the results were confirmed in subgroup analyses stratified according to sex, SSc subtype, Scl70 antibody positivity and previous and/or active digital ulcers.

Conclusion

There is interocular symmetry of the choroidal parameters in patients with SSc and controls included in our study. The parameters from one eye are representative of the fellow eye of a given patient. This conclusion may contribute to the design and interpretation of future studies. It also broadens our knowledge of SSc pathophysiology.

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

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

Serum levels of AGGF1: Potential association with cutaneous and cardiopulmonary involvements in systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune disease characterized by vasculopathy, aberrant immune activation, and extensive tissue fibrosis of the skin and internal organs. Because of the complicated nature of its pathogenesis, the underlying mechanisms of SSc remain incompletely understood. Angiogenic factor with a G-patch domain and a Forkhead-associated domain 1 (AGGF1) is a critical factor in angiogenesis expressed on vascular endothelial cells, associated with inflammatory and fibrotic responses. To elucidate the possible implication of AGGF1 in SSc pathogenesis, we investigated the association between serum AGGF1 levels and clinical manifestations in SSc patients. We conducted a cross-sectional analysis of AGGF1 levels in sera from 60 SSc patients and 19 healthy controls with enzyme-linked immunosorbent assay. Serum AGGF1 levels in SSc patients were significantly higher than those in healthy individuals. In particular, diffuse cutaneous SSc patients with shorter disease duration had higher levels compared to those with longer disease duration and limited cutaneous SSc patients. Patients with higher serum AGGF1 levels had a higher incidence of digital ulcers, higher modified Rodnan Skin Scores (mRSS), elevated serum Krebs von den Lungen-6 (KL-6) levels, C-reactive protein levels, and right ventricular systolic pressures (RVSP) on the echocardiogram, whereas they had reduced percentage of vital capacity (%VC) and percentage of diffusing capacity of the lungs for carbon monoxide (%DLCO) in pulmonary functional tests. In line, serum AGGF1 levels were significantly correlated with mRSS, serum KL-6 and surfactant protein D levels, RVSP, and %DLCO. These results uncovered notable correlations between serum AGGF1 levels and key cutaneous and vascular involvements in SSc, suggesting potential roles of AGGF1 in SSc pathogenesis.

Molecular Changes Implicate Angiogenesis and Arterial Remodeling in Systemic Sclerosis-Associated and Idiopathic Pulmonary Hypertension

BACKGROUND

Pulmonary hypertension (PH) is a common complication of systemic sclerosis (SSc) and a leading cause of mortality among patients with this disease. PH can also occur as an idiopathic condition (idiopathic pulmonary arterial hypertension). Investigation of transcriptomic alterations in vascular populations is critical to elucidating cellular mechanisms underlying pathobiology of SSc-associated and idiopathic PH.

METHODS

We analyzed single-cell RNA sequencing profiles of endothelial and perivascular mesenchymal populations from explanted lung tissue of patients with SSc-associated PH (n=16), idiopathic pulmonary arterial hypertension (n=3), and healthy controls (n=15). Findings were validated by immunofluorescence staining of explanted human lung tissue.

RESULTS

Three disease-associated endothelial populations emerged. Two angiogenic endothelial cell (EC) subtypes markedly expanded in SSc-associated PH lungs: tip ECs expressing canonical tip markers PGF and APLN and phalanx ECs expressing genes associated with vascular development, endothelial barrier integrity, and Notch signaling. Gene regulatory network analysis suggested enrichment of Smad1 (SMAD family member 1) and PPAR-γ (peroxisome proliferator-activated receptor-γ) regulon activities in these 2 populations, respectively. Mapping of potential ligand-receptor interactions highlighted Notch, apelin-APJ (apelin receptor), and angiopoietin-Tie (tyrosine kinase with immunoglobulin-like and EGF-like domains 1) signaling pathways between angiogenic ECs and perivascular cells. Transitional cells, expressing both endothelial and pericyte/smooth muscle cell markers, provided evidence for the presence of endothelial-to-mesenchymal transition. Transcriptional programs associated with arterial endothelial dysfunction implicated VEGF-A (vascular endothelial growth factor-A), TGF-β1 (transforming growth factor beta-1), angiotensin, and TNFSF12 (tumor necrosis factor ligand superfamily member 12)/TWEAK (TNF-related weak inducer of apoptosis) in the injury/remodeling phenotype of PH arterial ECs.

CONCLUSIONS

These data provide high-resolution insights into the complexity and plasticity of the pulmonary endothelium in SSc-associated PH and idiopathic pulmonary arterial hypertension and provide direct molecular insights into soluble mediators and transcription factors driving PH vasculopathy.

Recent Insights into Cellular and Molecular Mechanisms of Defective Angiogenesis in Systemic Sclerosis

In systemic sclerosis (SSc, or scleroderma), defective angiogenesis, clinically manifesting with abnormal capillary architecture and severe capillary reduction, represents a hallmark of early-stage disease, usually preceding the onset of tissue fibrosis, and is caused by several cellular and molecular mechanisms affecting microvascular endothelial cells with different outcomes. Indeed, once damaged, endothelial cells can be dysfunctionally activated, thus becoming unable to undergo angiogenesis and promoting perivascular inflammation. They can also undergo apoptosis, transdifferentiate into profibrotic myofibroblasts, or acquire a senescence-associated secretory phenotype characterized by the release of exosomes and several profibrotic and proinflammatory mediators. In this narrative review, we aimed to give a comprehensive overview of recent studies dealing with the cellular and molecular mechanisms underlying SSc defective angiogenesis and the related endothelial cell dysfunctions, mainly the endothelial-to-mesenchymal transition process. We also discussed potential novel vascular treatment strategies able to restore the angiogenic process and reduce the endothelial-to-mesenchymal transition in this complex disease.

Neurological, cardiac, musculoskeletal, and renal manifestations of scleroderma along with insights into its genetics, pathophysiology, diagnostic, and therapeutic updates

Background

Scleroderma, also referred to as systemic sclerosis, is a multifaceted autoimmune condition characterized by abnormal fibrosis and impaired vascular function. Pathologically, it encompasses the persistent presence of inflammation, abnormal collagen buildup, and restructuring of blood vessels in various organs, resulting in a wide range of clinical symptoms. This review incorporates the most recent scientific literature on scleroderma, with a particular emphasis on its pathophysiology, clinical manifestations, diagnostic approaches, and treatment options.

Methodology

A comprehensive investigation was carried out on numerous databases, such as PubMed, MEDLINE, Scopus, Web of Science, and Google Scholar, to collect pertinent studies covering diverse facets of scleroderma research.

Results

Scleroderma presents with a range of systemic manifestations, such as interstitial lung disease, gastrointestinal dysmotility, Raynaud's phenomenon, pulmonary arterial hypertension, renal complications, neurological symptoms, and cardiac abnormalities. Serological markers, such as antinuclear antibodies, anti-centromere antibodies, and anti-topoisomerase antibodies, are important for classifying diseases and predicting their outcomes.

Discussion

The precise identification of scleroderma is crucial for promptly and correctly implementing effective treatment plans. Treatment approaches aim to improve symptoms, reduce complications, and slow down the progression of the disease. An integrated approach that combines pharmacological agents, including immunosuppressants, endothelin receptor antagonists, and prostanoids, with nonpharmacological interventions such as physical and occupational therapy is essential for maximizing patient care.

Conclusion

Through the clarification of existing gaps in knowledge and identification of emerging trends, our goal is to improve the accuracy of diagnosis, enhance the effectiveness of therapeutic interventions, and ultimately enhance the overall quality of life for individuals suffering from scleroderma. Ongoing cooperation and creative research are necessary to advance the field and achieve improved patient outcomes and new therapeutic discoveries.

Endothelial Dysfunction in Systemic Sclerosis

Systemic sclerosis, commonly known as scleroderma, is an autoimmune disorder characterized by vascular abnormalities, autoimmunity, and multiorgan fibrosis. The exact etiology is not known but believed to be triggered by environmental agents in a genetically susceptible host. Vascular symptoms such as the Raynaud phenomenon often precede other fibrotic manifestations such as skin thickening indicating that vascular dysfunction is the primary event. Endothelial damage and activation occur early, possibly triggered by various infectious agents and autoantibodies. Endothelial dysfunction, along with defects in endothelial progenitor cells, leads to defective angiogenesis and vasculogenesis. Endothelial to mesenchymal cell transformation is another seminal event during pathogenesis that progresses to tissue fibrosis. The goal of the review is to discuss the molecular aspect of the endothelial dysfunction that leads to the development of systemic sclerosis.

The interplay of inflammation and remodeling in the pathogenesis of chronic rhinosinusitis: current understanding and future directions

Chronic rhinosinusitis (CRS), a common clinical condition characterized by persistent mucosal inflammation and tissue remodeling, has a complex pathogenesis that is intricately linked to innate and adaptive immunity. A number of studies have demonstrated that a variety of immune cells and cytokines that play a vital role in mediating inflammation in CRS are also involved in remodeling of the nasal mucosa and the cells as well as different cytokines involved in remodeling in CRS are also able to exert some influence on inflammation, even though the exact relationship between inflammation and remodeling in CRS has not yet been fully elucidated. In this review, the potential role of immune cells and cytokines in regulating inflammation and remodeling of CRS mucosa has been described, starting with the immune cells and cytokines that act together in inflammation and remodeling. The goal is to aid researchers in understanding intimate connection between inflammation and remodeling of CRS and to offer novel ideas for future research.

Evaluation of choroidal vascularity index in systemic sclerosis patients

OBJECTIVE

To investigate the comparison of choroidal vascularity index (CVI) between patients with systemic sclerosis and healthy individuals.

METHODS

This study was designed prospective non-randomized cross-sectional study. Eighty-six eyes (43 patients) with limited cutaneous systemic sclerosis (lcSSc), 60 eyes (30 patients) with diffuse cutaneous systemic sclerosis (dcSSc) and 60 eyes (30 subjects) of age-and sex-matched healthy individuals were recruited. Subfoveal choroidal thickness, CVI and modified Rodnan skin score (mRSS) were evaluated. Enhanced depth imaging- optical coherence tomography scans were binarized using Niblack's autolocal threshold and CVI was determined as the luminal choroidal area/total choroidal area ratio.

RESULTS

The mean CCT values were 268.00±68.59 µm, 286.90±70.88 µm, 321.73±94.13 µm in lcSSc group, dcSSc group and control group, respectively. The mean CVI was 61.84±2.84% in lcSSc group, 54.62±5.84% in dcSSc group and 62.41±4.13% in control group (p=0.001). The mean CVI of the SSc patients was 58.91±5.58 and there was significant difference between control group (p<0.001). The mean mRSS was 3.84±2.50 in lcSSc group and 14.07±6.81 in dcSSc group (p<0.001). There was a statistically significant negative correlation between mRSS and CVI (r=-0.448, p<0.001) CONCLUSION: Choroidal vascularity index provides valuable information to monitor the disease progression and lower CVI values seem to be related to the disease severity in patients with systemic sclerosis.

Soluble markers of B cell activation suggest a role of B cells in the pathogenesis of systemic sclerosis-associated pulmonary arterial hypertension

Introduction

Soluble markers of B cell activation are interesting diagnostic and prognostic tools in autoimmune diseases. Data in systemic sclerosis (SSc) are scarce and few studies focused on their association with disease characteristics.

Methods

1. Serum levels of 14 B cell biomarkers (β2-microglobulin, rheumatoid factor (RF), immunoglobulins (Ig) G, IgA, IgM, BAFF, APRIL, soluble (s)TACI, sBCMA sCD21, sCD23, sCD25, sCD27, CXCL13) were measured in SSc patients and healthy controls (HC). 2. Associations between these biomarkers and SSc characteristics were assessed. 3. The pathophysiological relevance of identified associations was explored by studying protein production in B cell culture supernatant.

Results

In a discovery panel of 80 SSc patients encompassing the broad spectrum of disease manifestations, we observed a higher frequency of RF positivity, and increased levels of β2-microglobulin, IgG and CXCL13 compared with HC. We found significant associations between several biomarkers and SSc characteristics related to disease phenotype, activity and severity. Especially, serum IgG levels were associated with pulmonary hypertension (PH); β2-microglobulin with Nt-pro-BNP and DLCO; and BAFF with peak tricuspid regurgitation velocity (TRV). In a validation cohort of limited cutaneous SSc patients without extensive ILD, we observed lower serum IgG levels, and higher β2-microglobulin, sBCMA, sCD23 and sCD27 levels in patients with pulmonary arterial hypertension (PAH). BAFF levels strongly correlated with Nt-pro-BNP levels, FVC/DLCO ratio and peak TRV in SSc-PAH patients. Cultured SSc B cells showed increased production of various angiogenic factors (angiogenin, angiopoietin-1, VEGFR-1, PDGF-AA, MMP-8, TIMP-1, L-selectin) and decreased production of angiopoietin-2 compared to HC.

Conclusion

Soluble markers of B cell activation could be relevant tools to assess organ involvements, activity and severity in SSc. Their associations with PAH could plead for a role of B cell activation in the pathogenesis of pulmonary microangiopathy. B cells may contribute to SSc vasculopathy through production of angiogenic mediators.

Management of Endothelial Dysfunction in Systemic Sclerosis: Current and Developing Strategies

Systemic Sclerosis (SSc) is an autoimmune disease marked by dysregulation of the immune system, tissue fibrosis and dysfunction of the vasculature. Vascular damage, remodeling and inadequate endothelial repair are hallmarks of the disease. Since early stages of SSc, damage and apoptosis of endothelial cells (ECs) can lead to perivascular inflammation, oxidative stress and tissue hypoxia, resulting in multiple clinical manifestations. Raynaud's phenomenon, edematous puffy hands, digital ulcers, pulmonary artery hypertension, erectile dysfunction, scleroderma renal crisis and heart involvement severely affect quality of life and survival. Understanding pathogenic aspects and biomarkers that reflect endothelial damage in SSc is essential to guide therapeutic interventions. Treatment approaches described for SSc-associated vasculopathy include pharmacological options to improve blood flow and tissue perfusion and, more recently, cellular therapy to enhance endothelial repair, promote angiogenesis and heal injuries. This mini-review examines the current knowledge on cellular and molecular aspects of SSc vasculopathy, as well as established and developing therapeutic approaches for improving the vascular compartment.

Contribution to the peripheral vasculopathy and endothelial cell dysfunction by CXCL4 in Systemic Sclerosis

BACKGROUND

CXCL4, a chemokine with anti-angiogenic property, is involved in systemic sclerosis (SSc) related pulmonary arterial hypertension (PAH).

OBJECTIVE

To investigated the contribution of CXCL4 to SSc development by focusing on the correlation of circulatory CXCL4 levels with their peripheral vasculopathy, and the effect of CXCL4 on endothelial cell dysfunction and the potential signaling.

METHODS

We measured the plasma CXCL4 levels in 58 patients with SSc, 10 patients with the very early diagnosis of SSc (VEDOSS), and 80 healthy controls (HCs). Then, CXCL4 concentrations were correlated with clinical features, especially the peripheral vasculopathy. These observations were further validated in an additional cohort. Moreover, we studied the anti-angiogenic effects of CXCL4 and the underlying downstream signaling in human umbilical vein endothelial cells (HUVECs) in vitro.

RESULTS

Circulating CXCL4 levels were 103.62 % higher in patients with SSc and 201.51 % higher in patients with VEDOSS than matched HCs, which were confirmed in two independent cohorts. CXCL4 levels were associated with digital ulcers (DU) and nailfold videocapillaroscopy (NVC) abnormalities in SSc. The proliferation, migration, and tube formation of HUVECs were inhibited by CXCL4 or SSc derived plasma, which reversed by CXCL4 neutralizing antibody, but failed by CXCR3 inhibitor. CXCL4 downregulated the transcription factor Friend leukaemia integration factor-1 (Fli-1) via c-Abl signaling. Furthermore, CXCL4 blocked the transforming growth factor (TGF) -β or platelet-derived growth factor (PDGF) induced cell proliferation of HUVECs.

CONCLUSIONS

CXCL4 may contribute to peripheral vasculopathy in SSc by downregulating Fli-1 via c-Abl signaling in endothelial cells and interfering angiogenesis.

Endocan and Circulating Progenitor Cells in Women with Systemic Sclerosis: Association with Inflammation and Pulmonary Hypertension

BACKGROUND

Systemic sclerosis (SSc) is characterized by early vasculopathy and fibrosis in the skin, lungs, and other tissues. Vascular manifestations of SSc include Raynaud's phenomenon, digital ulcers, and pulmonary artery hypertension (PAH). PAH is the second most common cause of mortality in SSc. Circulating CD34+ cells associated with cardiovascular health status in several conditions, including chronic immune-inflammatory disease. CD34+ cell numbers have been found inconstantly reduced in SSc. Endocan, a proteoglycan expressed by endothelial cells, was recently suggested as a marker of vascular stress. We tested the relationships among CD34+ cells, endocan, inflammatory markers, vitamin D levels, and clinical parameters in SSc patients with PAH.

METHODS

Standard echocardiography was performed. Vitamin D levels, CD34+ cells, inflammatory markers, endocan plasma levels were determined in 36 female SSc patients (24 diffuse/12 limited) and 36 matched controls (HC).

RESULTS

We found no difference in CD34+ and vitamin D levels in SSc as compared to controls; ESR, CRP, fibrinogen, endocan, sPAP were higher in SSc with respect to controls. We found a correlation between endocan and: CD34+ cells (r: -0.540, p = 0.002), pulmonary arterial pressure (sPAP) (r: 0.565, p < 0.001), tricuspid annular plane excursion (TAPSE) (r: -0.311, p < 0.01), and E/A ratio (r: -0.487, p < 0.001), but not with ejection fraction (r: -0.057, p = 0.785) in SSc. CD34+ cells correlate with fibrinogen (r: -0.619, p < 0.001), sPAP (r: -0.404, p = 0.011), E/A (r: 0.470, p < 0.005 in SSc.

CONCLUSION

CD34+ cell number was significantly correlated with endocan levels and with sPAP in SSc; endocan and CD34+ progenitor cells might be suggested as a potential marker of disease status.

Evaluation of the direct effects on retinal and choroidal microvascularity of systemic scleroderma

OBJECTIVE

Ocular involvement in systemic sclerosis (SSc) has been documented; however it cannot be distinguished from secondary changes due to concomitant hypertension.Therefore, the aim of this prospective cross-sectional study was to demonstrate the direct effects of Ssc on retinal and choroidal microvasculature in patients without hypertension.

METHODS

47 SSc patients and 44 age- and sex-matched healthy control subjects were enrolled in this study. In fundus examination: Increased vascular tortitis, focal or general arteriolar narrowing, arteriovenous notch, severe exudation, microhemorrhage, and pigment epithelial changes in the retina of SSc patients without hypertension were investigated. Patients with at least two of the above findings were considered to have retinopathy After that, patients were divided into two groups according to the presence of retinopathy in this study. Retinal and choroidal microvasculature were evaluated using optical coherence tomography angiography.

RESULTS

There was a significant decrease in SSc patients with retinopathy in both superficial capillary plexus vessel density (SCP VD) and deep capillary plexus vessel density (DCP VD) compared to the control group. Full avascular zone (FAZ) evaluation tool variables (FAZ area, FAZ perimeter, foveal density) were significantly lower in all Ssc patients than in the healthy control group. It was found that the flow in the 1 mm and 3 mm circular area (Outer Retina 1-3 mm Flow Area) increased significantly in Ssc patients with retinopathy. Choroidal flow (Choriocapillaries 1 mm Flow Area) was statistically lower in Ssc patients with retinopathy.

CONCLUSIONS

We have showed an increase in the outer retina 1-3 mm flow area (circular area of the outer retina fold covering the fovea) despite the decrease in vascular density and choroidal thickness in scleroderma patients with retinopathy. Hence, we first demonstrated that Ssc itself may have an effect on retinal and choroidal microvasculature, independent of hypertension.

Correlation of retinal and choroidal microvascular impairment in systemic sclerosis

Purpose

To investigate the correlation between retinal and choroidal microperfusion in patients with systemic sclerosis (SSc) using optical coherence tomography angiography (OCTA).

Methods

In this cross-sectional study SSc patients without clinical evidence of ocular involvement and healthy, age- and sex-matched volunteers were recruited. Participants underwent specific rheumatological and ophthalmological examinations, including optical coherence tomography (OCT) and OCTA. Retinal and choroidal thicknesses as well as perfusion of the retina and the choroidal sublayers were evaluated.

Results

A total of 15 SSc patients (30 eyes) with a median disease duration of 60 months and 15 matched, healthy controls (30 eyes) were recruited. OCT data revealed a significantly lower macular volume, as well as Sattler’s layer and Haller’s layer thickness in SSc patients compared to controls. In OCTA analysis, the perfusion of both retinal plexus as well as Sattler’s and Haller’s layer were significantly reduced in the SSc group. Patients with a disease duration of more than 60 months showed a statistically significant positive correlation between retinal and choroidal malperfusion, while those with a shorter disease duration did not.

Conclusion

OCTA analysis confirmed impairment of retinal and choroidal microperfusion in SSc patients, supporting the hypothesis of wide spreading vascular injury. In early stages, either the retinal or the choroidal perfusion seems to be involved, while later on, vascular impairment affects both tissues alike. Both, retinal and choroidal examinations should be considered as soon as the diagnosis of SSc is made, to avoid missing out on early alterations.

Endothelial cells and endothelial progenitor cells in the pathogenesis of systemic sclerosis

Systemic sclerosis (SSc) is a connective tissue disease characterized by excessive fibrosis, microvasculopathy, and autoimmunity. Endothelial cell (EC) injury and subsequent endothelial cell dysfunction is believed to be an initial event that eventually leads to a vicious pathogenic cycle. This process is further enhanced by defective angiogenesis and vasculogenesis, as the vascular repair machinery does not work properly. Endothelial progenitor cells (EPCs) are functionally and quantitatively insufficient to recover the endothelium in SSc patients. The dysfunctional ECs and EPCs not only trigger the formation of typical vascular lesions, such as progressive intimal fibrosis in small arteries and the loss of capillaries, but also promote a series of inflammatory and profibrotic processes, such as endothelial-mesenchymal transition and recruitment and accumulation of monocytic EPCs with profibrotic properties. These processes together contribute to the accumulation of extracellular matrix in the affected tissue. This review features current insights into the roles of ECs and EPCs in the pathogenesis of SSc.

Choroidal and retinal thickness in systemic autoimmune and inflammatory diseases: A review

To identify the risk of relapse and subclinical inflammatory stages of systemic autoimmune diseases, new tools are needed. In the recent years, choroidal thickness and retinal thickness measured with ocular coherence tomography (OCT) have been proposed as an inflammatory marker for different systemic diseases, especially for conditions with a vascular component. Our aim in this article is to review the literature regarding the role of choroidal and retinal thickness as a potential inflammatory marker in systemic autoimmune and inflammatory diseases measured by OCT. Current literature suggests that the choroid of patients thickens in active phases of inflammatory diseases with vascular involvement. This pattern is observed in lupus, systemic sclerosis, Behçet disease, spondylitis, and familial Mediterranean fever. Choroidal thickness may decrease with biological treatments, along with systemic inflammation. Repeated flares and long-term disease, however, may thin the choroid, as a result of prolonged insult to the microvasculature and subsequent atrophy. Less is known about the effect of these diseases on retinal thickness. In summary, choroidal and retinal thickness measured by OCT may be promising markers for inflammation in systemic autoimmune and inflammatory diseases; however, more studies are warranted before generalizing choroidal thickness measurements by OCT as a marker for disease activity. The role of retinal thickness is more unclear due to a lack of studies in this field.

Role of Semaphorins in Immunopathologies and Rheumatic Diseases

Rheumatic diseases are disorders characterized by joint inflammation, in which other organs are also affected. There are more than two hundred rheumatic diseases, the most studied so far are rheumatoid arthritis, osteoarthritis, spondyloarthritis, systemic lupus erythematosus, and systemic sclerosis. The semaphorin family is a large group of proteins initially described as axon guidance molecules involved in nervous system development. Studies have demonstrated that semaphorins play a role in other processes such as the regulation of immunity, angiogenesis, bone remodeling, apoptosis, and cell migration and invasion. Moreover, semaphorins have been related to the pathogenesis of multiple sclerosis, asthma, Alzheimer, myocarditis, atherosclerosis, fibrotic diseases, osteopetrosis, and cancer. The aim of this review is to summarize current knowledge regarding the role of semaphorins in rheumatic diseases, and discuss their potential applications as therapeutic targets to treat these disorders.

A randomised placebo-controlled double-blind trial to assess the safety of intramuscular administration of allogeneic mesenchymal stromal cells for digital ulcers in systemic sclerosis: the MANUS Trial protocol

INTRODUCTION

Systemic sclerosis (SSc) is an autoimmune disease characterised by inflammation, fibrosis and vasculopathy. Digital ulcers (DUs) are a frequent manifestation of vasculopathy in patients with SSc. Despite recent advances in pharmacological treatments, DU still have major health and economic implications. As there is currently no proven therapeutic strategy to promote DU healing, new treatments are urgently needed. Mesenchymal stem or stromal cells (MSCs) may provide a novel therapy for DU in SSc, because of their immunomodulatory and vasculoregenerative properties. Allogeneic MSC therapy involves functionally competent MSCs from healthy donors and may be used as 'off-the-shelf' available treatment. This study will evaluate whether allogeneic MSC therapy is a safe and potentially efficacious treatment for DU of SSc.

METHODS AND ANALYSIS

The MANUS (Mesenchymal stromal cells for Angiogenesis and Neovascularization in digital Ulcers of Systemic Sclerosis) Trial is a double-blind randomised placebo-controlled trial. 20 patients with SSc with refractory DU will be randomised to receive eight intramuscular injections with either placebo or 50*10⁶ MSCs. The primary outcome is the toxicity of the treatment at 12 weeks after administration. Secondary outcomes include (serious) adverse events, number and time to healing of DU, pain, reported hand function, quality of life and SSc disease activity. We will also evaluate changes in nailfold capillaroscopy pattern, as well as biochemical parameters and biomarkers in peripheral blood and skin biopsies. Follow-up visits will be scheduled at 48 hours and 2, 4, 8, 12, 24 and 52 weeks post-treatment. If the results confirm safety, feasibility and potential efficacy, a large multicentre randomised controlled trial with longer follow-up will be initiated focusing on efficacy.

ETHICS AND DISSEMINATION

The study has been approved by the Dutch Central Committee on Research Concerning Human Subjects (protocol no: NL51705.000.15). The results will be disseminated through patient associations and conventional scientific channels.

TRIAL REGISTRATION NUMBER

NCT03211793; Pre-results.

The Role of Endothelial Progenitors in the Repair of Vascular Damage in Systemic Sclerosis

Systemic sclerosis (SSc) is a connective tissue disease characterized by a complex pathological process where the main scenario is represented by progressive loss of microvascular bed, with the consequent progressive fibrotic changes in involved organ and tissues. Although most aspects of vascular injury in scleroderma are poorly understood, recent data suggest that the scleroderma impairment of neovascularization could be related to both angiogenesis and vasculogenesis failure. Particularly, compensatory angiogenesis does not occur normally in spite of an important increase in many angiogenic factors either in SSc skin or serum. Besides insufficient angiogenesis, the contribution of defective vasculogenesis to SSc vasculopathy has been extensively studied. Over the last decades, our understanding of the processes responsible for the formation of new vessels after tissue ischemia has increased. In the past, adult neovascularization was thought to depend mainly on angiogenesis (a process by which new vessels are formed by the proliferation and migration of mature endothelial cells). More recently, increased evidence suggests that stem cells mobilize from the bone marrow into the peripheral blood (PB), differentiate in circulating endothelial progenitors (EPCs), and home to site of ischemia to contribute to de novo vessel formation. Significant advances have been made in understanding the biology of EPCs, and molecular mechanisms regulating EPC function. Autologous EPCs now are becoming a novel treatment option for therapeutic vascularization and vascular repair, mainly in ischemic diseases. However, different diseases, such as cardiovascular diseases, diabetes, and peripheral artery ischemia are related to EPC dysfunction. Several studies have shown that EPCs can be detected in the PB of patients with SSc and are impaired in their function. Based on an online literature search (PubMed, EMBASE, and Web of Science, last updated December 2017) using keywords related to “endothelial progenitor cells” and “Systemic Sclerosis,” “scleroderma vasculopathy,” “angiogenesis,” “vasculogenesis,” this review gives an overview on the large body of data of current research in this issue, including controversies over the identity and functions of EPCs, their meaning as biomarker of SSc microangiopathy and their clinical potency.

A normal diffusing capacity of the lungs for carbon monoxide is rare in incidental pulmonary arterial hypertension in systemic sclerosis: Data from the Pulmonary Hypertension Assessment and Recognition of Outcomes in Scleroderma cohort

Objective:

Our purpose was to determine the frequency of normal diffusing capacity for carbon monoxide defined as ⩾70% predicted, in those diagnosed with pulmonary arterial hypertension in the Pulmonary Hypertension Assessment and Recognition of Outcomes in Scleroderma cohort. We compared those with normal diffusing capacity for carbon monoxide to those with reduced diffusing capacity for carbon monoxide <70% in order to better clarify the role of pulmonary function testing as a screening test for pulmonary arterial hypertension and to better understand this population.

Methods:

Entry criteria included a right heart catheterization with mean pulmonary artery pressure ⩾25 mm Hg and pulmonary capillary wedge pressure ⩽15 mm Hg. Demographics, echocardiogram variables, B-type natriuretic peptide levels, right heart catheterization findings, and survival were described for both groups.

Results:

Of (n = 202), 11 (5.4%) had a diffusing capacity for carbon monoxide of ⩾70% versus 191 (94.6%) who had a diffusing capacity for carbon monoxide <70%. There were no identified statistical differences between the groups. Left atrium size was 4.1 cm in the normal diffusing capacity for carbon monoxide patients compared to 3.7 cm in the low diffusing capacity for carbon monoxide group but did not reach statistical significance. There were no statistically significant differences in survival. On repeat testing, seven patients subsequently developed a diffusing capacity for carbon monoxide <70%.

Conclusion:

Pulmonary Hypertension Assessment and Recognition of Outcomes in Scleroderma data suggest that it is very rare for a patient to develop pulmonary arterial hypertension with a preserved diffusing capacity for carbon monoxide. The data support the importance of obtaining diffusing capacity for carbon monoxide and that a patient with a normal diffusing capacity for carbon monoxide while suspected to have systemic sclerosis-pulmonary arterial hypertension should be considered critically. Diffusing capacity for carbon monoxide >70% was present in too few patients to find significant differences in B-type natriuretic peptide and atrium size. Future research should seek to confirm abnormal B-type natriuretic peptide, increased left atrium size, and other evidence of myocardial involvement on diffusing capacity for carbon monoxide.

The Convergence of Vasculopathy and Vasculitis: Computer Mapping Analysis of 2 Renal Biopsies in a Patient with both Systemic Sclerosis and ANCA-Related Vasculitis

Scleroderma vasculopathy and ANCA (antineutrophil cytoplasmic antibodies)-associated glomerulonephritis have rarely been reported to occur simultaneously in one patient. Herein, we report a patient who presented with a classic constellation of clinical and laboratory findings of systemic scleroderma and was subsequently found to be positive for p-ANCA. Two renal biopsies, performed 5 months apart, demonstrated typical changes of the two entities in both acute and "healed" phases, which were analyzed by computer mapping techniques. The two renal biopsies were serially sectioned and stained routinely, and with CD31 and CD34 as endothelial markers. The slides were digitized, aligned and analyzed. Each glomerular tuft was sequentially studied in terms of total area (µm²) and each biopsy was individually profiled. All arterial vessels were sequentially studied with whole vessel and luminal areas delineated and ratios calculated. The initial biopsy contained 32 glomeruli almost all with extensive fibrinoid necrosis and destruction of the capillary network. The arterial vessels (interlobular and arcuate) showed intimal edema with luminal occlusion. CD31/CD34 stains showed variable endothelial intactness but demonstrated the luminal size shifts. The second biopsy had 37 glomeruli that were either segmentally or globally sclerotic with no active changes. The vessels were now normally patent. Each glomerular tuft and arterial vessel in both biopsies was analyzed as a serial section histogram documenting these changes. These studies depict the rare occurrence of two entities together, the scleroderma kidney vasculopathy and the glomerulonephritis of ANCA-associated vasculitis syndrome both in an acute and healing phase, profiled by computer mapping techniques.

Angiogenesis Dysregulation in the Pathogenesis of Systemic Sclerosis

Systemic sclerosis is a chronic autoimmune connective tissue disease characterized by vascular injury and fibrosis and by an impaired angiogenesis which cannot ensure an efficient vascular recovery. Vascular injury is responsible for hypoxia and tissual ischemia which are the primary triggers for angiogenesis and are not able to induce a compensatory angiogenesis. This review article is focused on current knowledge on the mechanisms responsible for angiogenesis dysregulation in systemic sclerosis.

Histone Deacetylase 5 Is Overexpressed in Scleroderma Endothelial Cells and Impairs Angiogenesis via Repression of Proangiogenic Factors

OBJECTIVE

Vascular dysfunction represents a disease-initiating event in systemic sclerosis (SSc; scleroderma). Results of recent studies suggest that epigenetic dysregulation impairs normal angiogenesis and can result in abnormal patterns of blood vessel growth. Histone deacetylases (HDACs) control endothelial cell (EC) proliferation and regulate EC migration. Specifically, HDAC-5 appears to be antiangiogenic. This study was undertaken to test whether HDAC-5 contributes to impaired angiogenesis in SSc by repressing proangiogenic factors in ECs.

METHODS

Dermal ECs were isolated from patients with diffuse cutaneous SSc and healthy controls. Angiogenesis was assessed using an in vitro Matrigel tube formation assay. An assay for transposase-accessible chromatin using sequencing (ATAC-seq) was performed to assess and localize the genome-wide effects of HDAC5 knockdown on chromatin accessibility.

RESULTS

The expression of HDAC5 was significantly increased in ECs from patients with SSc compared to healthy control ECs. Silencing of HDAC5 in SSc ECs restored normal angiogenesis. HDAC5 knockdown followed by ATAC-seq assay in SSc ECs identified key HDAC5-regulated genes involved in angiogenesis and fibrosis, such as CYR61, PVRL2, and FSTL1. Simultaneous knockdown of HDAC5 in conjunction with either CYR61, PVRL2, or FSTL1 inhibited angiogenesis in SSc ECs. Conversely, overexpression of these genes individually led to an increase in tube formation as assessed by Matrigel assay, suggesting that these genes play functional roles in the impairment of angiogenesis in SSc.

CONCLUSION

Several novel HDAC5-regulated target genes associated with impaired angiogenesis were identified in SSc ECs by ATAC-seq. The results of this study provide a potential link between epigenetic regulation and impaired angiogenesis in SSc, and identify a novel mechanism for the dysregulated angiogenesis that characterizes this disease.

The impact of transcription factor Fli1 deficiency on the regulation of angiogenesis

The insufficiency of Friend leukaemia virus integration 1 (Fli1), a member of the Ets family transcription factors, is implicated in the pathogenesis of vasculopathy associated with systemic sclerosis (SSc). Fli1 deficiency accelerates early steps of angiogenesis, including detachment of pre-existing pericytes and extracellular matrix degradation by endothelial proteinases, but the impact of Fli1 deficiency on the other steps of angiogenesis has not been investigated. Therefore, we evaluated the effect of Fli1 deficiency on migration, proliferation, cell survival and tube formation of human dermal microvascular endothelial cells (HDMECs). HDMECs transfected with FLI1 siRNA exhibited a greater migratory property in scratch assay and transwell migration assay and a higher proliferation rate in BrdU assay than HDMECs transfected with non-silencing scrambled RNA. In flow cytometry-based apoptosis assay, FLI1 siRNA-transduced HDMECs revealed the decreased number of annexin and propidium iodide-double-positive apoptotic cells compared with control cells, reflecting the promotion of cell survival. On the other hand, tubulogenic activity on Matrigel was remarkably suppressed in Fli1-deficient HDMECs relative to control cells. These results indicate that Fli1 deficiency promotes migration, proliferation and cell survival, while abating tube formation of endothelial cells, suggesting that Fli1 deficiency is potentially attributable to the development of both proliferative obliterative vasculopathy (occlusion of arterioles and small arteries) and destructive vasculopathy (loss of small vessels) characteristic of SSc vasculopathy.

The "myth" of loss of angiogenesis in systemic sclerosis: a pivotal early pathogenetic process or just a late unavoidable event?

Systemic sclerosis is considered a disease dominated by a "loss of angiogenesis", although in its early phases evidence indicates a disturbed angiogenic response only. In fact, microvascular changes are primarily due to endothelial cell injury, triggering downstream significant enlargement of the capillary in an inflammatory environment, followed by capillary rupture (microhemorrhages). Subsequent pro-angiogenic efforts lead to an aberrant angiogenesis and, eventually, to a total loss of vessel repair and regeneration (loss of angiogenesis). This clearly suggests that the pathogenetic process has a steady progression: from an early excessive pro-angiogenesis, to an aberrant microvascular regeneration, then ending with a late loss of angiogenesis. Herein, we suggest the loss of angiogenesis should not be considered as an overall "myth" characterizing systemic sclerosis but as a very late event of the vascular pathogenesis. Future research should be oriented essentially on the earlier phases dominated by excessive pro-angiogenesis and microvascular aberration.

Recent updates in experimental protocols for endothelial cells

Scleroderma (systemic sclerosis, SSc) is a multisystem autoimmune disease of unknown etiology. The disease is characterized by vascular disorder, activation of the immune system, and excessive deposition of matrix proteins in the skin and involved organs. The vascular disorder is believed to play a crucial role in disease pathogenesis. Endothelial injury and dysfunction, subsequent capillary loss and arteriolar wall thickness, are well documented in all involved organs. The resulting tissue hypoxia and ischemia fail to initiate new vessel formation leading to progressive loss of vasculature with no apparent replenishment. Issues related to endothelial injury/activation, dysfunction and failure of angio/vasculogenesis are central to the understanding of SSc vasculopathy. Isolation of endothelial cells and cells involved in the genesis of new vessels is enormously important in the investigation of mechanisms involved in SSc vasculopathy. Nevertheless, this goal has been difficult to achieve in view of the charac­teristic slow growth of endothelial cells, the high demand for growth factors and rapid growth of contaminating cells and the scarcity of circulating cells involved in angio/vasculogenesis hampered this line of investigation. Nonetheless, recent technologic progress in the last decade provided us with the tools to isolate vascular cells with an acceptable purity based on unique cell surface markers using immunoselection methods. The purpose of this review is to update the readers on current technical state-of-the-art methods of isolation and propagation of vascular cells. We wish that this review will spark interest in more investigations of this crucial phase of SSc pathogenesis.

Decreased expression of neuropilin-1 as a novel key factor contributing to peripheral microvasculopathy and defective angiogenesis in systemic sclerosis

OBJECTIVES

In systemic sclerosis (SSc), vascular involvement is characterised by vascular endothelial growth factor (VEGF)-A/VEGF receptor (VEGFR) system disturbances. Neuropilin-1 (NRP1), a receptor for both class-3 semaphorins (Sema3s) and VEGF-A, is required for optimal VEGF-A/VEGFR-2 signalling. Here, we investigated the possible involvement of Sema3A/NRP1 axis in SSc.

METHODS

Circulating Sema3A and soluble NRP1 (sNRP1) were measured in patients with SSc and controls. NRP1 and Sema3A expression in skin biopsies was evaluated by immunofluorescence and western blotting. NRP1 expression was assessed in SSc and healthy dermal microvascular endothelial cells (SSc-MVECs and H-MVECs), and in SSc and control endothelial progenitor cell (EPC)-derived endothelial cells (ECs). The possible impact of transcription factor Friend leukaemia integration 1 (Fli1) deficiency on endothelial NRP1 expression was investigated by gene silencing. The binding of Fli1 to NRP1 gene promoter was evaluated using chromatin immunoprecipitation. Capillary morphogenesis was performed on Matrigel.

RESULTS

Decreased sNRP1 levels in SSc were associated with active and late nailfold videocapillaroscopy patterns and digital ulcers. No difference in Sema3A was found between patients and controls. NRP1 was significantly decreased in SSc-MVECs both ex vivo and in vitro. NRP1 and Fli1 significantly decreased in H-MVECs challenged with SSc sera, while they were not different in SSc and control EPC-derived ECs. Fli1 occupied the NRP1 gene promoter and Fli1 gene silencing reduced NRP1 expression in H-MVECs. NRP1 gene silencing in H-MVECs resulted in a significantly impaired angiogenic capacity comparable to that of cells treated with SSc sera.

CONCLUSION

In SSc, NRP1 deficiency may be an additional factor in the perturbed VEGF-A/VEGFR-2 system contributing to peripheral microvasculopathy and defective angiogenesis.

Impaired angiogenesis as a feature of digital ulcers in systemic sclerosis

Impaired angiogenesis in systemic sclerosis has a major role in tissue injury pathogenesis. Our objective was to determine whether angiogenic biomarkers (vascular endothelial growth factor (VEGF), endoglin, and endostatin) are related to microvascular damage and to determine their predictive value for new digital ulcers (DU). The main outcome of the study was the occurrence of a new digital ulcer during 3-year follow-up. This prospective longitudinal study was performed between October 2011 and December 2014. Seventy-seven patients definitely diagnosed with systemic sclerosis where divided into two groups: those with active DU at baseline and those with no DU until enrollment. Patients were matched by sex and age with healthy controls. Serum levels of VEGF, endoglin, and endostatin were measured at enrollment, and several nailfold videocapillaroscopies were performed during the 3-year follow-up. Serum levels of VEGF were lower (245.06, 158.68-347.33; p < 0.001) and those of endoglin were higher (3.013, 1.463-7.023; p < 0.001) in patients with active DU than those with no DU history (339.49, 202.00-730.93/1.879, 0.840-3.280), and they were higher than those found in controls (178.030, 101.267-222.102)/0.277, 0.154-0.713), respectively. No differences in endostatin levels were found between groups (p = 0.450). Endoglin was the only biomarker significantly different (p = 0.031) between patients with diffuse versus limited systemic sclerosis and between early, active, and late patterns (p = 0.020). VEGF was identified as an independent predictor for the development of new DU. Our study confirmed the relationship between angiogenic vascular biomarkers and the occurrence of DU. Endoglin and VEGF serum levels are potential risk factors, and VEGF has a predictive value for the occurrence of new DU.

Simvastatin prevents vascular complications in the chronic reactive oxygen species murine model of systemic sclerosis

Aims Systemic sclerosis (SSc) is characterized by vasculopathy and organ fibrosis. Although microvascular alterations are very well characterized, structural and functional abnormalities of large vessels are not well defined. Therefore, we evaluated the effect of simvastatin administration on aortic and small renal arteries thickening, and on myofibroblasts differentiation in a murine model of SSc. Methods and results SSc was induced in BALB/c mice by daily subcutaneous injections of hypochlorous acid (HOCl, 100 μl) for 6 weeks. Mice (n = 23) were randomized to receive: HOCl (n = 10); HOCl plus simvastatin (40 mg/kg; n = 8); or vehicle (n = 5). Simvastatin administration started 30 min after HOCl injection, and up to week 6. Aortic and small renal arteries intima-media thickness was evaluated by histological analysis. Immunostaining for α-smooth muscle actin (SMA), vascular endothelial growth factor receptor 2 (VEGFR2), and CD31 in aortic tissues was performed to evaluate myofibroblast differentiation and endothelial markers.In HOCl-treated mice, intima-media thickening with reduced lumen diameter was observed in the aorta and in small renal arteries and simvastatin administration prevented this increase. Aortic and renal myofibroblasts count, as expressed by α-SMA + density, was lower in the group of mice treated with simvastatin compared to HOCl-treated mice. Simvastatin prevented the reduction in VEGFR2 and CD31 expression induced by HOCl. Conclusions The administration of simvastatin regulates collagen deposition in the aortic tissues and in the small renal arteries by modulating myofibroblasts differentiation and vascular markers. Further studies are needed to better address the effect of statins in the macrovascular component of SSc.

Evaluation of choroidal thickness in patients with scleroderma

PURPOSE

To investigate the choroidal thickness in patients with scleroderma and to compare them with healthy control subjects.

METHODS

Forty-six patients with scleroderma (3 male and 43 female) and 31 healthy controls (6 male and 25 female) were included in the study. Twenty-five patients had limited-type and 21 patients had diffuse-type scleroderma. Only left eyes of the patients and control subjects were used in the analysis. Demographic features of all the patients and control subjects were recorded. Each subject underwent ophthalmological examinations including refraction, visual acuity, intraocular pressure, axial length (AXL) measurement, slit-lamp biomicroscopy, and fundus examination. Body mass index (BMI) was estimated for all participants.

RESULTS

There were no significant differences between the patients with scleroderma and the control subjects in terms of age, gender, BMI, mean AXL, and mean spherical equivalent refractive error (SE) (P=0.1, P=0.086, P=0.37, P=0.55, and P=0.072 respectively). The patients with scleroderma had significantly thinner nasal, temporal, and subfoveal choroid than the healthy control subjects (P1=0.012, P2=0.046, and P3<0.001, respectively). There were no significant differences between the patients with limited-type and diffuse-type scleroderma in terms of age, gender, BMI, mean AXL, mean SE, nasal, temporal, and subfoveal choroidal thicknesses (all P>0.05).

CONCLUSIONS

Choroidal thickness in patients with scleroderma was significantly less than healthy control subjects. Vasculopathy in scleroderma is characterized by obliteration of arterioles and reduced capillary density may cause atrophy of choroid in patients with scleroderma.

Scleroderma dermal microvascular endothelial cells exhibit defective response to pro-angiogenic chemokines

OBJECTIVES

Angiogenesis plays a critical role in SSc (scleroderma). The aim of this study was to examine the expression of growth-regulated protein-γ (Gro-γ/CXCL3), granulocyte chemotactic protein 2 (GCP-2/CXCL6) and their receptor CXCR2 in endothelial cells (ECs) isolated from SSc skin and determine whether these cells mount an angiogenic response towards pro-angiogenic chemokines. The downstream signalling pathways as well as the pro-angiogenic transcription factor inhibitor of DNA-binding protein 1 (Id-1) were also examined.

METHODS

Skin biopsies were obtained from patients with dcSSc. ECs were isolated via magnetic positive selection. Angiogenesis was measured by EC chemotaxis assay.

RESULTS

Gro-γ/CXCL3 and GCP-2/CXCL6 were minimally expressed in both skin types but elevated in SSc serum. Pro-angiogenic chemokine mRNA was greater in SSc ECs than in normal ECs. SSc ECs did not migrate to vascular endothelial growth factor (VEGF), Gro-γ/CXCL3, GCP-2/CXCL6 or CXCL16. The signalling pathways stimulated by these chemokines were also dysregulated. Id-1 mRNA in SSc ECs was lower compared with normal ECs, and overexpression of Id-1 in SSc ECs increased their ability to migrate towards VEGF and CXCL16.

CONCLUSION

Our results show that SSc ECs are unable to respond to pro-angiogenic chemokines despite their increased expression in serum and ECs. This might be due to the differences in the signalling pathways activated by these chemokines in normal vs SSc ECs. In addition, the lower expression of Id-1 also decreases the angiogenic response. The inability of pro-angiogenic chemokines to promote EC migration provides an additional mechanism for the impaired angiogenesis that characterizes SSc.

Vasculopathy in scleroderma

Systemic sclerosis (SSc) is a multisystem connective tissue disorder featured by vascular injury and fibrosis of the skin and various internal organs with autoimmune background. Although the pathogenesis of SSc still remains elusive, it is generally accepted that initial vascular injury due to autoimmunity and/or environmental factors causes structural and functional abnormalities of vasculature which eventually result in the constitutive activation of fibroblasts in various organs. Structural alterations consist of destructive vasculopathy (loss of small vessels) and proliferative obliterative vasculopathy (occlusion of arterioles and small arteries with fibro-proliferative change) caused by impaired compensatory vasculogenesis and angiogenesis. Impaired function of SSc vasculature includes the altered expression of cell adhesion molecules predominantly inducing Th2 and Th17 cell infiltration, endothelial dysfunction primarily due to the low availability of nitric oxide, the activated endothelial-to-mesenchymal transition leading to fibro-proliferative vascular change and tissue fibrosis, and the impaired coagulation/fibrinolysis system promoting the formation of intravascular fibrin deposits. Recent new insights into the therapeutic mechanisms of intravenous cyclophosphamide pulse and bosentan and the establishment of a new SSc animal model (Klf5 (+/-);Fli1 (+/-) mice) provide us useful clues to further understand the development of vascular alterations characteristic of SSc. This article overviewed the present understanding of the pathogenesis of SSc vasculopathy.

Endothelin receptor blockade ameliorates vascular fragility in endothelial cell-specific Fli-1-knockout mice by increasing Fli-1 DNA binding ability

OBJECTIVE

It is generally accepted that blockade of endothelin receptors has potentially beneficial effects on vasculopathy associated with systemic sclerosis (SSc). The aim of this study was to clarify the molecular mechanism underlying these effects using endothelial cell-specific Fli-1-knockout (Fli-1 ECKO) mice, an animal model of SSc vasculopathy.

METHODS

Levels of messenger RNA for target genes and the expression and phosphorylation levels of target proteins were determined in human and murine dermal microvascular endothelial cells by real-time quantitative reverse transcription-polymerase chain reaction and immunoblotting, respectively. The binding of Fli-1 to the target gene promoters was evaluated using chromatin immunoprecipitation. Expression levels of Fli-1 and α-smooth muscle actin in murine skin were evaluated using immunohistochemistry. Vascular structure and permeability were evaluated in mice injected with fluorescein isothiocyanate-dextran and Evans blue dye, respectively.

RESULTS

In human dermal microvascular endothelial cells, endothelin 1 induced phosphorylation of Fli-1 at Thr(312) through the sequential activation of c-Abl and protein kinase Cδ, leading to a decrease in Fli-1 protein levels as well as a decrease in binding of Fli-1 to the target gene promoters, whereas bosentan treatment reversed those effects. In Fli-1 ECKO mice, 4 weeks of treatment with bosentan increased endothelial Fli-1 expression, resulting in vascular stabilization and the restoration of impaired leaky vessels.

CONCLUSION

The vascular fragility of Fli-1 ECKO mice was improved by bosentan through the normalization of Fli-1 protein levels and activity in endothelial cells, which may explain, in part, the mechanism underlying the beneficial effects of endothelin receptor blockade on SSc vasculopathy.

Involvement of collagen-binding heat shock protein 47 in scleroderma-associated fibrosis

Uncontrolled fibrosis of skin and internal organs is the main characteristic of scleroderma, and collagen is a major extracellular matrix protein that deposits in the fibrotic organs. As the chaperone of collagen, heat shock protein 47 (HSP47) is closely related with the development of fibrosis. To explore the potential function of HSP47 in the pathogenesis of scleroderma, the clinical, in vivo and in vitro studies were performed. In clinical, the increased mRNA level of HSP47 was observed in the skin fibroblasts and PBMC from scleroderma patients, and the enhanced protein level of HSP47 was also detected in the skin biopsy and plasma of the above patients. Unexpectedly, the enhanced levels of HSP47 were positively correlated with the presence of anti-centromere antibody in scleroderma patients. Moreover, a high expression of HSP47 was found in the skin lesion of BLM-induced scleroderma mouse model. Further in vitro studies demonstrated that HSP47 knockdown could block the intracellular and extracellular collagen over-productions induced by exogenous TGF-β. Therefore, the results in this study provide direct evidence that HSP47 is involved in the pathogenesis of scleroderma. The high expression of HSP47 can be detected in the circulatory system of scleroderma patients, indicating that HSP47 may become a pathological marker to assess the progression of scleroderma, and also explain the systemic fibrosis of scleroderma. Meanwhile, collagen over-expression is blocked by HSP47 knockdown, suggesting the possibility that HSP47 can be a potential therapeutic target for scleroderma.

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.

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.

Development of an autoimmune syndrome affecting the skin and internal organs in P-selectin glycoprotein ligand 1 leukocyte receptor-deficient mice

OBJECTIVE

To define and characterize the progression of the spontaneous autoimmune disease that develops in mice in the absence of the leukocyte adhesion receptor P-selectin glycoprotein ligand 1 (PSGL-1).

METHODS

Skin-resident immune cells from PSGL-1-deficient mice and C57BL/6 control mice of different ages were isolated and analyzed by flow cytometry. Biochemical parameters were analyzed in mouse serum and urine, and the presence of serum autoantibodies was investigated. Skin and internal organs were extracted, and their structure was analyzed histologically.

RESULTS

Skin-resident innate and adaptive immune cells from PSGL-1(-/-) mice had a proinflammatory phenotype with an imbalanced T effector cell:Treg cell ratio. Sera from PSGL-1(-/-) mice had circulating autoantibodies commonly detected in connective tissue-related human autoimmune diseases. Biochemical and histologic analysis of skin and internal organs revealed skin fibrosis and structural and functional abnormalities in the lungs and kidneys. Furthermore, PSGL-1(-/-) mice exhibited vascular alterations, showing loss of dermal vessels, small vessel medial layer remodeling in the lungs and kidneys, and ischemic processes in the kidney that promote renal infarcts.

CONCLUSION

Our study demonstrates that immune system overactivation due to PSGL-1 deficiency triggers an autoimmune syndrome with characteristics similar to systemic sclerosis, including skin fibrosis, vascular alterations, and systemic organ involvement. These results suggest that PSGL-1 expression contributes to the maintenance of the homeostasis of the immune system and could act as a barrier for autoimmunity in mice.

Vascular biomarkers and correlation with peripheral vasculopathy in systemic sclerosis

Vascular disease is a hallmark of systemic sclerosis (SSc). It is present in every patient, being responsible both for the earliest clinical manifestations and the major life-threatening complications of the disease, and thus determining important morbidity and mortality. In SSc, progressive vascular injury leads to vascular tone dysfunction and reduced capillary blood flow, with consequent tissue ischemia and chronic hypoxia. These phenomena are often accompanied by abnormal levels of vascular factors. Microangiopathy in SSc may be easily assessed by nailfold videocapillaroscopy. The variety of derangements detected in the nailfold capillaries is accompanied by abnormal levels of different vascular mediators and appears to be the best evaluable predictor of the development of peripheral vascular complications, such as digital ulcers. The purpose of this review is to summarize in SSc the most relevant vascular biomarkers and the main associations between vascular biomarkers and capillaroscopic parameters and/or the presence of digital ulcers. Vascular biomarkers could become useful predictive factors of vascular damage in SSc, allowing an earlier management of vascular complications.

Pro- and antiangiogenic markers in patients with pulmonary complications of systemic scleroderma

Systemic sclerosis (SSc) is an autoimmune disorder characterized by skin and internal organs fibrosis and concomitant vascular abnormalities. Although SSc is considered mainly fibrosing disease, underlying vascular pathology plays a fundamental role in its pathogenesis. We have focused on positive and negative serum markers of angiogenesis and fibrosis (pigment epithelium-derived factor [PEDF], vascular endothelial growth factor [VEGF], and soluble VEGF receptor [sVEGFR]), in progressive SSc patients at baseline and after follow-up in relation to cardiopulmonary complications (systemic hypertension [HT], pulmonary arterial hypertension [PAH] and pulmonary fibrosis [PF]). VEGF and PEDF but not sVEGFR were reciprocally regulated in SSc progression. Moreover, VEGF/PEDF ratio significantly increased during follow up suggesting that it might be used as a biomarker of disease progression. No correlation between the studied markers and cardiopulmonary complications was observed. In conclusion, VEGF and PEDF level, and the VEGF/PEDF ratio are significantly changed in the course of SSc progression and these markers can be used to assess SSc activity.

New radiotracers for imaging of vascular targets in angiogenesis-related diseases

Tremendous advances over the last several decades in positron emission tomography (PET) and single photon emission computed tomography (SPECT) allow for targeted imaging of molecular and cellular events in the living systems. Angiogenesis, a multistep process regulated by the network of different angiogenic factors, has attracted world-wide interests, due to its pivotal role in the formation and progression of different diseases including cancer, cardiovascular diseases (CVD), and inflammation. In this review article, we will summarize the recent progress in PET or SPECT imaging of a wide variety of vascular targets in three major angiogenesis-related diseases: cancer, cardiovascular diseases, and inflammation. Faster drug development and patient stratification for a specific therapy will become possible with the facilitation of PET or SPECT imaging and it will be critical for the maximum benefit of patients.

Animal models of systemic sclerosis: their utility and limitations

Without doubt, animal models have provided significant insights into our understanding of the rheumatological diseases; however, no model has accurately replicated all aspects of any autoimmune disease. Recent years have seen a plethora of knockouts and transgenics that have contributed to our knowledge of the initiating events of systemic sclerosis, an autoimmune disease. In this review, the focus is on models of systemic sclerosis and how they have progressed our understanding of fibrosis and vasculopathy, and whether they are relevant to the pathogenesis of systemic sclerosis.