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

The Pathogenic Role of Expanded CD8⁺CD28null Angiogenic T Cells in ANCA-Associated Vasculitis

Objectives: Angiogenic T cells (Tang) are crucial in promoting angiogenesis, with the loss of CD28 serving as a marker for highly differentiated and senescent T cells. This study aims to investigate the characteristics and potential roles of CD8+CD28null Tang in patients with ANCA-associated vasculitis (AAV). Methods: A cohort of AAV patients and matched healthy controls (HCs) were analyzed. Flow cytometry was used to assess the profiles of circulating CD8+CD28null Tang. In vitro functional assays were performed to evaluate the pathogenic properties of CD8+CD28null Tang. Results: CD8+CD28null Tang levels were significantly higher in the peripheral blood of AAV patients compared to HCs, and their levels were further increased in AAV patients with MPO⁺, p-ANCA⁺, or interstitial lung disease compared to their respective control groups. Additionally, there was a positive correlation between both the percentage and absolute count of CD8+CD28null Tang and the Birmingham Vasculitis Activity Score (BVAS). In patients with a good treatment response, both the percentage and absolute count of CD8+CD28null Tang were significantly reduced, and this reduction was positively correlated with the decrease in BVAS scores. In vitro studies revealed that CD8+CD28null Tang displayed enhanced chemotactic properties, induced apoptosis in human umbilical vein endothelial cells (HUVECs), and inhibited their proliferation, migration, and tube formation. Conclusions: AAV patients exhibit increased levels of circulating CD8+CD28null Tang, which can be reduced following effective treatment. Furthermore, CD8+CD28null Tang may contribute to the pathogenesis of AAV by promoting apoptosis and inhibiting the proliferation, migration, and tube formation of HUVECs.

Advances in the diagnosis of multiorgan involvement in systemic sclerosis: a focus on MRI

PURPOSE OF REVIEW

Systemic sclerosis (SSc) is a rare chronic multisystem autoimmune disease characterized by endothelial dysfunction, tissue hypoxia, and diffuse organ fibrosis. MRI provides a radiation free approach to noninvasively assess the key manifestations of SSc in multiple organs. The purpose of this review is to summarize recent advances in MRI techniques to provide diagnostic and prognostic information in patients with SSc.

RECENT FINDINGS

MRI can probe processes that play a key role in the development of SSc-related complications, including neointima proliferation, fibrosis, and hypoxia. Feature tracking and parametric mapping MRI can detect cardiac involvement at the subclinical level. Contrast-free MRI angiography with Digital Artery Volume Index (DAVIX) assessment allow comprehensive assessment of hand involvement. T1 mapping and BOLD imaging can assess SSc effects on skeletal muscle, and lung MRI is becoming a key method for imaging of interstitial lung disease. As a new exciting application, the sodium content of the skin can be quantified by 23 Na MRI reflective of glycosaminoglycan content.

SUMMARY

Recent advances in MRI provide a unique opportunity to study the key pathophysiologic processes and clinical manifestations of SSc in multiple organs noninvasively, which can pave the way for the development of effective therapies.

Single-cell transcriptomes and chromatin accessibility of endothelial cells unravel transcription factors associated with dysregulated angiogenesis in systemic sclerosis

OBJECTIVES

Vasculopathy emerges early in systemic sclerosis (SSc) and links to endothelial cell (EC) injury and angiogenesis. Understanding EC transcriptomes and epigenomes is crucial for unravelling the mechanisms involved.

METHODS

Transcriptomes and chromatin accessibility were assessed by single-cell RNA sequencing and single-nucleus transposase-accessible chromatin sequencing. Immunofluorescent staining of skin and proteomics assay were employed to confirm the altered SSc EC phenotypes. Gain-of-function assay was used to evaluate the effects of ETS transcription factors on human dermal ECs (hDECs).

RESULTS

Both control and SSc ECs shared transcriptomic signatures of vascular linages (arterial, capillary and venous ECs) and lymphatic ECs. Arterial ECs in SSc showed reduced number and increased expression of genes associated with apoptosis. Two distinct EC subpopulations, tip and proliferating ECs, were markedly upregulated in SSc, indicating enhanced proangiogenic and proliferative activities. Molecular features of aberrant SSc-ECs were associated with disease pathogenesis and clinical traits of SSc, such as skin fibrosis and digital ulcers. Ligand-receptor analysis demonstrated altered intercellular networks of SSc EC subpopulations with perivascular and immune cells. Furthermore, the integration of open chromatin profiles with transcriptomic analysis suggested an increased accessibility of regulatory elements for ETS family transcription factors in SSc ECs. Overexpression of ETS genes in hDECs suggested ELK4, ERF and ETS1 may orchestrate arterial apoptosis and dysregulated angiogenesis in SSc.

CONCLUSIONS

This study unveils transcriptional and chromatin alterations in driving endovascular dysregulation in SSc, proposing ELK4, ERF and ETS1 as novel targets in ECs for addressing vascular complications in the condition.

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.

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.

Epigenetic mechanisms driving the pathogenesis of systemic lupus erythematosus, systemic sclerosis and dermatomyositis

Autoimmune connective tissue disorders, including systemic lupus erythematosus, systemic sclerosis (SSc) and dermatomyositis (DM), often manifest with debilitating cutaneous lesions and can result in systemic organ damage that may be life-threatening. Despite recent therapeutic advancements, many patients still experience low rates of sustained remission and significant treatment toxicity. While genetic predisposition plays a role in these connective tissue disorders, the relatively low concordance rates among monozygotic twins (ranging from approximately 4% for SSc to about 11%-50% for SLE) have prompted increased scrutiny of the epigenetic factors contributing to these diseases. In this review, we explore some seminal studies and key findings to provide a comprehensive understanding of how dysregulated epigenetic mechanisms can contribute to the development of SLE, SSc and DM.

Treatable Traits in Systemic Sclerosis

Systemic sclerosis (SSc) is a chronic systemic disease within the spectrum of connective tissue diseases, specifically characterized by vascular abnormalities and inflammatory and fibrotic involvement of the skin and internal organs resulting in high morbidity and mortality. The clinical phenotype of SSc is heterogeneous, and serum autoantibodies together with the extent of skin involvement have a predictive value in the risk stratification. Current recommendations include an organ-based management according to the predominant involvement with only limited individual factors included in the treatment algorithm. Similar to what has been proposed for other chronic diseases, we hypothesize that a "treatable trait" approach based on relevant phenotypes and endotypes could address the unmet needs in SSc stratification and treatment to maximize the outcomes. We provide herein a comprehensive review and a critical discussion of the literature regarding potential treatable traits in SSc, focusing on established and candidate biomarkers, with the purpose of setting the bases for a precision medicine-based approach. The discussion, structured based on the organ involvement, allows to conjugate the pathogenetic mechanisms of tissue injury with the proposed predictors, particularly autoantibodies and other serum biomarkers. Ultimately, we are convinced that precision medicine is the ideal guide to manage a complex condition such as SSc for which available treatments are largely unsatisfactory.

Copeptin as a Biomarker of Microcirculation Alterations in Systemic Sclerosis

Background

Systemic sclerosis is a connective tissue disease characterized by vasculopathy and progressive fibrosis, leading to multiorgan dysfunction. Given the complex and not fully elucidated pathogenesis, biomarkers of rapid disease progression and therapeutic response are lacking. Copeptin, which reflects vasopressin activity in serum, is used in diagnosing or prognosing different cardiometabolic conditions.

Objective

The aim of study was to investigate the concentration of copeptin in patients with systemic sclerosis and correlate it with specific clinical symptoms.

Patients and Methods

Serum copeptin was measured in patients with systemic sclerosis (34 women and 3 men; mean age 57.6 years) and in healthy individuals (n=30) using commercially available ELISA kits. According to the criteria of LeRoy our systemic sclerosis cohort consisted of 17 patients with limited cutaneous systemic sclerosis (45.9%) and 20 diffuse cutaneous systemic sclerosis patients (54.1%). According to the criteria of LeRoy our systemic sclerosis cohort consisted of 17 patients with limited cutaneous systemic sclerosis (45.9%) and 20 diffuse cutaneous systemic sclerosis patients (54.1%). The median duration of the disease was 10 [4-14] years.

Results

We found significantly higher copeptin concentration in patients with systemic sclerosis (4.21 pmol/L [3.04-5.42]) in comparison to control group (3.40 pmol/L [2.38-3.76], p<0.01). Copeptin significantly correlated with Raynaud's condition score (r=0.801, p<0.05). Patients with "late" capillaroscopic patterns had higher copeptin concentrations (5.37 pmol/L [4.29-8.06]) than patients with "early" (2.43 pmol/L [2.25-3.20], p<0.05) and "active" patterns (3.93 pmol/L [2.92-5.16], p<0.05]). Copeptin was found to be significantly higher in SSc patients with DUs (5.71 pmol/L [IQR 4.85-8.06]) when compared to SSc patients without DUs (3.31 pmol/L, [2.28-4.30], p<0.05). Additionally, copeptin concentration had good diagnostic accuracy in discriminating between patients with and without digital ulcers (AUC=0.863). Alprostadil decreased copeptin concentration from 4.96 [4.02-6.01] to 3.86 pmol/L [3.17-4.63] (p<0.01) after 4-6 cycles of administration.

Conclusion

Our findings suggest that copeptin may be a promising biomarker of microcirculation alterations in systemic sclerosis.

Serum of Post-COVID-19 Syndrome Patients with or without ME/CFS Differentially Affects Endothelial Cell Function In Vitro

A proportion of COVID-19 reconvalescent patients develop post-COVID-19 syndrome (PCS) including a subgroup fulfilling diagnostic criteria of Myalgic encephalomyelitis/Chronic Fatigue Syndrome (PCS/CFS). Recently, endothelial dysfunction (ED) has been demonstrated in these patients, but the mechanisms remain elusive. Therefore, we investigated the effects of patients’ sera on endothelia cells (ECs) in vitro. PCS (n = 17), PCS/CFS (n = 13), and healthy controls (HC, n = 14) were screened for serum anti-endothelial cell autoantibodies (AECAs) and dysregulated cytokines. Serum-treated ECs were analysed for the induction of activation markers and the release of small molecules by flow cytometry. Moreover, the angiogenic potential of sera was measured in a tube formation assay. While only marginal differences between patient groups were observed for serum cytokines, AECA binding to ECs was significantly increased in PCS/CFS patients. Surprisingly, PCS and PCS/CFS sera reduced surface levels of several EC activation markers. PCS sera enhanced the release of molecules associated with vascular remodelling and significantly promoted angiogenesis in vitro compared to the PCS/CFS and HC groups. Additionally, sera from both patient cohorts induced the release of molecules involved in inhibition of nitric oxide-mediated endothelial relaxation. Overall, PCS and PCS/CFS patients′ sera differed in their AECA content and their functional effects on ECs, i.e., secretion profiles and angiogenic potential. We hypothesise a pro-angiogenic effect of PCS sera as a compensatory mechanism to ED which is absent in PCS/CFS patients.

Quantitative assessment of left ventricular myocardial involvement in patients with connective tissue disease: a 3.0T contrast-enhanced cardiovascular magnetic resonance study

The aim of this study was to evaluate left ventricular (LV) myocardial involvement in connective tissue disease (CTD) patients using multiparemetric imaging derived from cardiovascular magnetic resonance (CMR). CMR was performed on 146 CTD patients (comprising of 74 with idiopathic inflammatory myopathy (IIM) and 72 with non-IIM) and 72 healthy controls and included measures of LV global strains [including peak strain (PS), peak systolic (PSSR) and diastolic strain rate (PDSR)], myocardial perfusion [including upslope, max signal intensity (MaxSI), and time to maximum signal intensity (TTM)], and late gadolinium enhancement (LGE) parameters. Univariable and multivariable linear regression analyses were performed to determine the association between LV deformation and microvascular perfusion, as well as LGE. Our results indicated that CTD patients had decreased global longitudinal PS (GLPS), PSSR, PDSR, and myocardial perfusion (all p < 0.017) compared with normal controls. Non-IIM patients exhibited lower LV global strain and longer TTM than IIM patients. The presence of LGE was independently associated with global radial PS (GRPS: β = - 0.165, p = 0.011) and global circumferential PS (GCPS: β =  - 0.122, p = 0.022). TTM was independently correlated with GLPS (β = - 0.156, p = 0.027). GLPS was the best indicator for differentiating CTD patients from normal controls (area under curve of 0.78). This study indicated that CTD patients showed impaired LV global myocardial deformation and microvascular perfusion, and presence of LGE. Cardiac involvement might be more severe in non-IIM patients than in IIM patients. Impaired microvascular perfusion and the presence of LGE were independently associated with LV global deformation.

Rho GTPase signaling in rheumatic diseases

Rho guanosine triphosphatase (GTPases), as molecular switches, have been identified to be dysregulated and involved in the pathogenesis of various rheumatic diseases, mainly including rheumatoid arthritis, osteoarthritis, systemic sclerosis, and systemic lupus erythematosus. Downstream pathways involving multiple types of cells, such as fibroblasts, chondrocytes, synoviocytes, and immunocytes are mediated by activated Rho GTPases to promote pathogenesis. Targeted therapy via inhibitors of Rho GTPases has been implicated in the treatment of rheumatic diseases, demonstrating promising effects. In this review, the effects of Rho GTPases in the pathogenesis of rheumatic diseases are summarized, and the Rho GTPase-mediated pathways are elucidated. Therapeutic strategies using Rho GTPase inhibitors in rheumatic diseases are also discussed to provide insights for further exploration of targeted therapy in preclinical studies and clinical practice. Future directions on studies of Rho GTPases in rheumatic diseases based on current understandings are provided.

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.

Prediction and primary prevention of major vascular complications in systemic sclerosis

OBJECTIVE

In Systemic Sclerosis (SSc), vasculopathy is the background of major vascular complications (MVCs), like digital ulcers (DUs), pulmonary arterial hypertension (PAH) and scleroderma renal crisis (SRC). We aimed to identify the predictors and to test the primary preventive effect of vasoactive/vasodilating drugs (VVD) for the development of MVCs in SSc MVCs-naïve patients.

METHODS

patients fulfilling the ACR/EULAR 2013 classification criteria for SSc without history of MVCs were eligible. Data about clinical manifestations, laboratory and instrumental assessments and treatments were retrospectively collected at baseline and latest available follow-up.

RESULTS

134 SSc patients were enrolled (mean age 56.5 years ± 14.2, females 88.1%, limited subset 61.9%, ACA positivity 60.4%). In a mean of 43 ± 19 months of follow-up 12 (9.0%) patients developed at least 1 MVC (10 DU, 2 PAH and 1 SRC). Dyspnoea and arthritis at baseline were independent predictors for MVCs development (p = 0.012, and p = 0.002 respectively). No primary preventive effect of VVD on MVCs development was found. However, sildenafil reduced the renal resistive index increase (p = 0.042) and alprostadil slowed the DLco decline (p = 0.029). Both iloprost and angiotensin-receptor blockers (ARBs) delayed MVCs development, while angiotensin converting enzyme inhibitors (ACEi) determined an earlier onset of such MCVs.

CONCLUSIONS

in SSc patients, our data confirm the role of arthritis and dyspnea as independent predictors of major vascular complications, in particular in MVCs-naïve patients. Prostanoids, sildenafil and ARBs, even in absence of a primary preventive action, might help in slowing disease progression and postponing the onset of MVCs.

Combining optical coherence tomography with magnetic resonance angiography and Doppler ultrasonography for clinical detection of scleroderma

Scleroderma (SD) is a rare and agnogenic autoimmune disease whose progression can be modified by medical or surgical intervention if detected early. Multimodality imaging makes early detection of SD possible based on the structural and functional findings from different imaging methods. Combining optical coherence tomography (OCT) with magnetic resonance angiography (MRA) and Doppler ultrasonography (DUS) to identify the typical structural and functional features that can exhibit significant differences between SD patients and healthy controls. In this study, six participants (three healthy volunteers and three SD patients) were recruited and clinically examined by a rheumatologist. Participants' fingers were scanned by MRA, DUS, and OCT, respectively. MRA and DSU imaging results showed that SD patients exhibited thicker finger skin, a loss of blood vessels, and lower blood flow, whereas OCT captured the high-resolution morphology changes of the skin, epidermal, dermis, and subcutaneous layers, demonstrating a distinct loss of the dermo-epidermal junction in SD patients. Multimodal imaging techniques offer a more comprehensive characterization of the morphological and functional information of biological tissues, which can assist physicians to achieve a more accurate SD diagnosis.

Quantitative analysis of pulmonary vasculature in systemic sclerosis at spirometry-gated chest CT

OBJECTIVE

To prospectively investigate whether differences in pulmonary vasculature exist in systemic sclerosis (SSc) and how they are distributed in patients with different pulmonary function.

METHODS

Seventy-four patients with SSc undergoing chest CT scan for interstitial lung disease (ILD) screening or follow-up were prospectively enrolled. A thorough clinical, laboratory and functional evaluation was performed the same day. Chest CT was spirometry gated at total lung capacity and images were analysed by two automated software programs to quantify emphysema, ILD patterns (ground-glass, reticular, honeycombing), and pulmonary vascular volume (PVV). Patients were divided in restricted (FVC% <80, DLco%<80), isolated DLco% reduction (iDLco- FVC%≥80, DLco%<80) and normals (FVC%≥80, DLco%≥80). Spearman ρ, Mann-Whitney tests and logistic regressions were used to assess for correlations, differences among groups and relationships between continuous variables.

RESULTS

Absolute and lung volume normalised PVV (PVV/LV) correlated inversely with functional parameters and positively with all ILD patterns (ρ=0.75 with ground glass, ρ=0.68 with reticular). PVV/LV was the only predictor of DLco at multivariate analysis (p=0.007). Meanwhile, the reticular pattern prevailed in peripheral regions and lower lung thirds, PVV/LV prevailed in central regions and middle lung thirds. iDLco group had a significantly higher PVV/LV (2.2%) than normal (1.6%), but lower than restricted ones (3.8%).

CONCLUSIONS

Chest CT in SSc detects a progressive increase in PVV/LV as DLco decreases. Redistribution of perfusion to less affected lung regions rather than angiogenesis nearby fibrotic lung may explain the results. Further studies to ascertain whether the increase in PVV/LV reflects a real increase in blood volume are needed.

The risk of circulating angiogenic T cells and subsets in patients with systemic sclerosis

To ascertain the number and percentage of angiogenic T (Tang) cell subsets by flow cytometry in systemic sclerosis (SSc), and their relation with specific clinical features. Thirty SSc patients and 15 healthy controls (HCs) were included. Luminex was performed to analyze the levels of interleukin (IL)-17A, vascular endothelial growth factor (VEGF), tumor necrosis factor-α, and vascular cell adhesion molecule (VCAM). The ratio of circulating CD3 + CD31 + CXCR4 + T (CD3 + Tang) cells and CD8+ CD31 + CXCR4 + T (CD8+ Tang) cells in SSc patients was enlarger than in HCs, while CD4 + CD31 + CXCR4 + T cells (CD4 + Tang) exhibited no difference between SSc patients and HCs. The number and percentage of Tang cells were higher in SSc patients with pulmonary artery hypertension (PAH) than in non-PAH SSc patients and HCs. The ratios of Tang cell subsets in nucleolar pattern-positive SSc patients were markedly raised as compared with their negative ones and HCs. Additionally, the percentage of circulating CD3 + Tang cells was positively associated with VEGF serum levels in SSc patients. Meanwhile, the rate of CD8+ tang cells might have been emphatically corresponded to VEGF and VCAM serum levels in SSc patients. These results imply that the increase in Tang cells in peripheral blood are associated with immunoregulatory disturbances in SSc patients.

Phase angle could be a marker of microvascular damage in systemic sclerosis

OBJECTIVES

Systemic sclerosis (SSc) is an autoimmune disease characterized by endothelial dysfunction with fibrosis of skin and internal organs. Integrity of the endothelial cell is important to its physiologic function such as production of angiogenetic factors. The aim of this study was to assess whether phase angle (PhA) is altered in patients with SSc and whether its values correlate with vascular endothelial growth factor (VEGF) and digital microvascular damage.

METHODS

Patients with SSc and matched healthy controls underwent VEGF determination and bioimpedentiometry (BIA) for PhA assessment. Clinical assessment, disease activity index (DAI), disease severity scale, and nailfold videocapillaroscopy (NCV) were performed in patients with SSc.

RESULTS

Fifty-five patients (46 women) with a mean age of 53.2 ± 13.7 y were studied. The mean value of VEGF was significantly higher in patients with SSc than in the healthy controls (240.3 ± 149.5 versus 139 ± 87.5; P = 0.035). The mean value of PhA was significantly lower in the patient grouop than in the healthy controls (4.51 ± 0.87 versus 5.22 ± 0.55; P < 0.0001). A significant positive correlation was found between VEGF and PhA (P = 0.009, beta coefficient = 1.48) in SSc patients. A negative correlation between VEGF and DAI (P = 0.048, β coefficient = 0.48) was found. PhA median value was significantly (P = 0.006) lower in patients with late pattern SSc (4.2 [2.5-5.3]). PhA median value was significantly (P < 0,0001) lower in patients with digital ulcers (DUs; 4.2 [2.5-5.3]) than in those without DUs (3.80 [2.50-5] versus 4.75 [2.80-7.3]). These data were confirmed in both female and male patients.

CONCLUSIONS

The evaluation of VEGF with PhA, NVC, and DUs could be useful to estimate cellular and microvascular damage in patients with SSc.

Systemic Sclerosis Serum Significantly Impairs the Multi-Step Lymphangiogenic Process: in Vitro Evidence

In systemic sclerosis (SSc), the possible involvement of lymphatic microcirculation and lymphangiogenesis has traditionally been overshadowed by the greater emphasis placed on dysfunctional blood vascular system and angiogenesis. In the present in vitro study, we explore for the first time whether the SSc microenvironment may interfere with lymphangiogenesis, a complex, multi-step process in which lymphatic microvascular endothelial cells (LMVECs) sprout, migrate, and proliferate to generate new lymphatic capillaries. Normal human adult dermal LMVECs from three donors were treated with serum from SSc patients (n = 8), serum from healthy individuals (n = 8), or recombinant human vascular endothelial growth factor (VEGF)-C as a positive control for lymphangiogenesis. Cell proliferation, Boyden chamber Matrigel chemoinvasion, wound healing capacity, and lymphatic capillary morphogenesis on Geltrex were assayed. VEGF-C serum levels were measured by enzyme-linked immunosorbent assay. Gene and protein expression levels of the lymphangiogenic orchestrators VEGF receptor-3 (VEGFR-3)/Flt-4 and neuropilin-2 (NRP-2) were determined by real-time PCR and Western blotting, respectively. Conditioning with SSc serum significantly inhibited LMVEC proliferation, Matrigel invasion, and wound healing capacity with respect to healthy serum. The ability of LMVECs to form lymphatic tubes on Geltrex was also severely compromised in the presence of SSc serum. VEGF-C levels were comparable in SSc and healthy sera. Treatment with SSc serum resulted in a significant downregulation of both VEGFR-3/Flt-4 and NRP-2 mRNA and protein levels. In SSc, the pathologic environment severely hampers every lymphangiogenesis step, likely through the reduction of pro-lymphangiogenic VEGFR-3/NRP-2 co-receptor signaling. The impairment of the lymphangiogenic process opens a new scenario underlying SSc vascular pathophysiology, which is worth investigating further.

Expression of apoptotic and proliferation factors in gastric mucosa of patients with systemic sclerosis correlates with form of the disease

Despite high prevalence of patients with gastric disease in systemic sclerosis (SSc), its pathogenesis is still poorly understood. We immunohistochemically analysed biopsies of gastric mucosa (GM) in 5 controls and 15 patients with different forms of SSc: limited cutaneous (lc), diffuse cutaneous moderate (sys1) and severe (sys2). The number of positive cells was analysed by a Kruskall-Wallis test, P < 0.05 was considered statistically significant. Percentage of proliferating (Ki-67 positive) cells was highest in sys1 (3% in superficial and 4,6% in deeper parts of GM), which dropped to 1% in sys2. Percentage of α-smooth muscle actin (α-SMA) positive cells was 5% in controls, 9% in superficial GM, while in deeper GM rose from 7% to 19% in sys1 and sys2, thus indicating increased myofibroblast population. Caspase-3 positive apoptotic cells characterized 1,5–2% of controls, 8% of superficial and 6% of deeper GM cells in sys1. In sys2, apoptosis affected 50% of surface epithelial and gland cells and 30% of deeper glands, and correlated with increased fibrosis and decreased syndecan-1 expression. Our data demonstrate that sys1 is the most „active” proliferating form of SSc. Sys2 characterize collagen deposition, surface epithelium defects, extensive apoptosis and low proliferation, GM atrophy and loss of function.

Imbalanced serum levels of Ang1, Ang2 and VEGF in systemic sclerosis: Integrated effects on microvascular reactivity

INTRODUCTION AND AIM

Microangiopathy is a hallmark of systemic sclerosis (SSc). It is a progressive process from an early inflammatory and proangiogenic environment to insufficient microvascular repair with loss of microvessels. The exact underlying mechanisms remain ill-defined. Aim of the study was to investigate whether imbalanced angiopoietins/VEGF serum profile should be related in SSc to the altered microvascular reactivity characterized by aberrant angiogenesis and avascularity.

MATERIALS AND METHODS

Serum levels of Angiopoietin-1 (Ang1), Angiopoietin-2 (Ang2) and VEGF were measured by ELISA in 47 SSc patients and 27 healthy controls. Microvascular alterations were assessed by nailfold videocapillaroscopy (NVC).

RESULTS

Serum concentrations of Ang1 were significantly lower [mean (S.D.): 21516.04 (11,441.035) pg/ml], and Ang2 significantly increased [25,89.55 (934.225) pg/ml] in SSc as compared with the control group [Ang1: 28,457.08 (10,431.905) pg/ml; Ang2: 1556.23 (481.255) pg/ml, p < 0.01, respectively], whereas VEGF did not differ significantly. The ratios of Ang1/Ang2 and Ang1/VEGF were significantly lower in SSc patients (8.346 ± 4.523 and 95.17 ± 75.0, respectively) than in healthy subjects (17.612 ± 6.731 p < 0.000001 and 183.11 ± 137.73; p = 0.004]. Formation of giant capillaries with vascular leakage and collapse was associated with significant increase in VEGF and concomitant Ang1 deficiency. Capillary loss was related to significant increase in VEGF with respect to those with preserved capillary number (395.12 ± 256.27 pg/mL vs. 254.80 ± 213.61 pg/mL) whereas elevated Ang2 levels induced more advanced capillary damage as indicated by the presence of the "Late" NVC pattern.

CONCLUSIONS

We found that serum levels of Ang1, Ang2 and VEGF are differentially expressed in SSc and altered Ang1/Ang2 profile might underlay the aberrant angiogenesis in SSc despite increase in VEGF. For the first time we identified that significant deficiency of Ang1 might be involved in early capillary enlargement, followed by collapse and lack of stable newly-formed vessels in VEGF-enriched environment, whereas Ang2 levels seem to increase later in disease progression and advanced microvascular damage ("Late" NVC pattern).

Perivascular Adventitial Fibroblast Specialization Accompanies T Cell Retention in the Inflamed Human Dermis

Perivascular accumulation of lymphocytes can be a prominent histopathologic feature of various human inflammatory skin diseases. Select examples include systemic sclerosis, spongiotic dermatitis, and cutaneous lupus. Although a large body of work has described various aspects of the endothelial and vascular smooth muscle layers in these diseases, the outer adventitial compartment is poorly explored. The goal of the current study was to characterize perivascular adventitial fibroblast states in inflammatory human skin diseases and relate these states to perivascular lymphocyte accumulation. In normal skin, adventitial fibroblasts are distinguished by CD90 expression, and dense perivascular lymphocytic infiltrates are uncommon. In systemic sclerosis, this compartment expands, but lymphocyte infiltrates remain sparse. In contrast, perivascular adventitial fibroblast expression of VCAM1 is upregulated in spongiotic dermatitis and lupus and is associated with a dense perivascular T cell infiltrate. VCAM1 expression marks transitioned fibroblasts that show some resemblance to the reticular stromal cells in secondary lymphoid organs. Expanded adventitial compartments with perivascular infiltrates similar to the human settings were not seen in the inflamed murine dermis. This species difference may hinder the dissection of aspects of perivascular adventitial pathology. The altered perivascular adventitial compartment and its associated reticular network form a niche for lymphocytes and appear to be fundamental in the development of an inflammatory pattern.

Slit2/Robo4 axis may contribute to endothelial cell dysfunction and angiogenesis disturbance in systemic sclerosis

OBJECTIVE

In systemic sclerosis (SSc), early microvascular injury is followed by impaired angiogenesis and peripheral capillary loss. Here, we investigated the possible contribution of the neurovascular guidance molecule Slit2 and its Roundabout (Robo) receptors to SSc-related endothelial cell dysfunction.

METHODS

Circulating Slit2 levels were measured in patients with SSc and healthy controls. Slit2, Robo1 and Robo4 expression was investigated in SSc and healthy skin biopsies and explanted dermal microvascular endothelial cells (MVECs). Slit2/Robo4 function in MVEC angiogenesis was studied by cell viability, wound healing and capillary-like tube formation assays.

RESULTS

Circulating Slit2 was significantly increased in either SSc or patients with a very early diagnosis of SSc (VEDOSS) compared with controls. Interestingly, serum Slit2 levels were raised in patients with VEDOSS with nailfold videocapillaroscopy (NVC) abnormalities, while they were similar in VEDOSS with normal NVC and controls. In SSc, Slit2 and Robo4 expression was upregulated in clinically affected skin and explanted MVECs in respect to controls. The angiogenic performance of healthy MVECs was significantly reduced after challenge with recombinant human Slit2 or SSc sera. These inhibitory effects were significantly attenuated when SSc sera were preincubated with an anti-Slit2 blocking antibody. In vitro angiogenesis was severely compromised in SSc-MVECs and could be significantly ameliorated by Slit2 neutralisation or ROBO4 gene silencing. Slit2/Robo4 axis interfered with angiogenesis through the inhibition of Src kinase phosphorylation.

CONCLUSIONS

In SSc, increased circulating levels of Slit2 and activation of the Slit2/Robo4 antiangiogenic axis may contribute to peripheral microangiopathy since the very early phase of the disease.

Vascular Leaking, a Pivotal and Early Pathogenetic Event in Systemic Sclerosis: Should the Door Be Closed?

The early phase of systemic sclerosis (SSc) presents edema as one of the main features: this is clinically evident in the digital swelling (puffy fingers) as well as in the edematous skin infiltration of the early active diffuse subset. Other organs could be affected by this same disease process, such as the lung (with the appearance of ground glass opacities) and the heart (with edematous changes on cardiac magnetic resonance imaging). The genesis of tissue edema is tightly linked to pathological changes in the endothelium: various reports demonstrated the effect of transforming growth factor β, vascular endothelial growth factor and hypoxia-reperfusion damage with reactive oxygen species generation in altering vascular permeability and extravasation, in particular in SSc. This condition has an alteration in the glycocalyx thickness, reducing the protection of the vessel wall and causing non-fibrotic interstitial edema, a marker of vascular leak. Moreover, changes in the junctional adhesion molecule family and other adhesion molecules, such as ICAM and VCAM, are associated with an increased myeloid cells' extravasation in the skin and increased myofibroblasts transformation with further vascular leak and cellular migration. This mini-review examines current knowledge on determinants of vascular leak in SSc, shedding light on the role of vascular protection. This could enhance further studies in the light of drug development for early treatment, suggesting that the control of vascular leakage should be considered in the same way that vasodilation and inflammation reduction, as potential therapeutic targets.

N-Formyl Peptide Receptors Induce Radical Oxygen Production in Fibroblasts Derived From Systemic Sclerosis by Interacting With a Cleaved Form of Urokinase Receptor

Systemic sclerosis (SSc) is a chronic autoimmune disease characterized by fibrosis, alteration in the microvasculature and immunologic abnormalities. It has been hypothesized that an abnormal redox state could regulate the persistent fibrotic phenotype in SSc patients. N-Formyl peptide receptors (FPRs) are chemotactic receptors overexpressed in fibroblasts derived from SSc patients. In this study, we demonstrated that stimulation of FPRs promotes the generation of reactive oxygen species (ROS) in skin fibroblasts. In fibroblast cells, ROS production was due to FPRs interaction with the urokinase receptor (uPAR) and to β₁ integrin engagement. FPRs cross-talk with uPAR and integrins led to Rac1 and ERKs activation. FPRs stimulation increased gp91phox and p67phox expression as well as the direct interaction between GTP-Rac1 and p67phox, thus promoting assembly and activation of the NADPH oxidase complex. FPRs functions occur through interaction with a specific domain of uPAR (residues ₈₈SRSRY₉₂) that can be exposed on the cell membrane by protease-mediated receptor cleavage. Immunohistochemistry analysis with a specific anti-SRSRY antibody showed increased expression of uPAR in a cleaved form, which exposes the SRSRY sequence at its N-terminus (DIIDIII-uPAR88–92) in skin biopsies from SSc patients. As expected by the increased expression of both FPRs and DII-DIII-uPAR_88-92, fibroblasts derived from SSc patients showed a significantly increase in ROS generation both at a basal level than after FPRs stimulation, as compared to fibroblasts from normal subjects. C37, a small molecule blocking the interaction between FPRs and uPAR, and selumetinib, a clinically approved MAPKK/ERK inhibitor, significantly inhibited FPRs-mediated ROS production in fibroblasts derived from SSc patients. Thus, FPRs, through the interaction with the uPA/uPAR system, can induce ROS generation in fibroblasts by activating the NADPH oxidase, playing a role in the alteration of the redox state observed in SSc.

Decreased global myocardial perfusion at adenosine stress as a potential new biomarker for microvascular disease in systemic sclerosis: a magnetic resonance study

Background

Patients with systemic sclerosis (SSc) have high cardiovascular mortality even though there is no or little increase in prevalence of epicardial coronary stenosis. First-pass perfusion on cardiovascular magnetic resonance (CMR) have detected perfusion defects indicative of microvascular disease, but the quantitative extent of hypoperfusion is not known. Therefore, we aimed to determine if patients with SSc have lower global myocardial perfusion (MP) at rest or during adenosine stress, compared to healthy controls, quantified with CMR.

Methods

Nineteen SSc patients (17 females, 61 ± 10 years) and 22 controls (10 females, 62 ± 11 years) underwent CMR. Twelve patients had limited cutaneous SSc and 7 patients had diffuse cutaneous SSc. One patient had pulmonary arterial hypertension (PAH). MP was quantified using coronary sinus flow (CSF) measurements at rest and during adenosine stress, divided by left ventricular mass (LVM).

Results

There was no difference in MP at rest between patients and controls (1.1 ± 0.5 vs. 1.1 ± 0.3 ml/min/g, P = 0.85) whereas SSc patients showed statistically significantly lower MP during adenosine stress (3.1 ± 0.9 vs. 4.2 ± 1.3 ml/min/g, P = 0.008). Three out of the 19 SSc patients showed fibrosis in the right ventricle insertion points despite absence of PAH. None had signs of myocardial infarction.

Conclusions

Patients with SSc have decreased MP during adenosine stress compared to healthy controls. Thus hypoperfusion at stress may be a sensitive marker of cardiac disease in SSc patients possibly signifying microvascular myocardial disease.