Endothelial Dysfunction in Systemic Sclerosis

Exploring endothelial dysfunction in major rheumatic diseases: current trends and future directions

The relationship between rheumatic diseases (RDs) and endothelial dysfunction (ED) is intricate and multifaceted, with chronic inflammation and immune system dysregulation playing key roles. RDs, including Osteoarthritis (OA), Rheumatoid arthritis (RA), Systemic Lupus erythematosus (SLE), Ankylosing spondylitis (AS), Psoriatic arthritis (PsA), Sjogren's syndrome (SS), Systemic sclerosis (SSc), Polymyalgia rheumatica (PMR) are characterized by chronic inflammation and immune dysregulation, leading to ED. ED is marked by reduced nitric oxide (NO) production, increased oxidative stress, and heightened pro-inflammatory and prothrombotic activities, which are crucial in the development of cardiovascular disease (CVD) and systemic inflammation. This association persists even in RD patients without conventional cardiovascular risk factors, suggesting a direct impact of RD-related inflammation on endothelial function. Studies also show that ED significantly contributes to atherosclerosis, thereby elevating cardiovascular risk in RD patients. This review synthesizes the molecular mechanisms connecting major RDs and ED, highlighting potential biomarkers and therapeutic targets. Ultimately, the review aims to enhance understanding of the complex interactions leading to ED in rheumatic patients and inform strategies to mitigate cardiovascular risks and improve patient outcomes.

Differential risk of autoimmune disorders in non-traumatic osteonecrosis: clue to pathogenesis

INTRODUCTION

Non-traumatic osteonecrosis is a frequent complication in patients with autoimmune disorders, though its prevalence varies markedly depending upon the type of disorder. Understanding the causes of this difference can help uncover the underlying pathophysiology of osteonecrosis and guide the development of effective preventive and therapeutic strategies.

AREAS COVERED

In this perspective study, we reviewed available databases, including PubMed, Cochrane Library, Scopus, and Web of Science, to explore why the risk of osteonecrosis varies among different autoimmune disorders. Is this variation primarily due to the disease's pathophysiology, the use of medications such as corticosteroids, or a combination of both? If both factors are involved, what is the extent of each contribution in this context?

EXPERT OPINION

Non-traumatic osteonecrosis is often induced by an interaction between disease pathophysiology and corticosteroid use. In patients with different autoimmune disorders but an identical history of corticosteroid use, the risk of osteonecrosis is influenced by how the underlying pathophysiology compromises bone health. In autoimmune disorders with multiple adverse effects on bone, such as SLE (systemic lupus erythematosus), there is a much higher risk of osteonecrosis compared to disorders with minimal impact on bone health, such as celiac disease and MS (multiple sclerosis).

Characterization of Circulating Vesicles of Complicated and Uncomplicated Systemic Sclerosis Patients and Their Role in Vascular Dysfunction

Extracellular vesicles (EVs) could be involved in the onset of systemic sclerosis (SSc) through the modulation of vascular function. Anyway, available data are contradictory, and further investigation would be necessary to clarify this aspect. Here, we characterized circulating EVs isolated from SSc patients and evaluated their effects on human vascular endothelial cells (HUVECs) and smooth muscle cells. In EVs from 13 complicated and 27 uncomplicated SSc patients and five healthy controls (HCs), we analyzed the size, concentration, and surface marker expression. In addition, EVs were used to stimulate HUVECs, and we evaluated cell viability, mitochondrial membrane potential, and nitric oxide (NO) and mitochondrial reactive oxygen species (MitoROS) release. In smooth muscle cells, the effects of EVs on calcium movement were examined. The results showed that the EVs of SSc patients expressed markers of T-lymphocyte/platelet/endothelial cell origin and were larger and more concentrated than those from HCs. In addition, the EVs of SSc patients reduced cell viability and mitochondrial membrane potential and increased NO and MitoROS release in HUVECs and intracellular calcium in smooth muscle cells. In conclusion, we found a specific pattern for EVs isolated from SSc patients, which could have a pathogenic role through direct actions on endothelial and smooth muscle cells.

Retinal microvascular dysfunction in systemic sclerosis

BACKGROUND AND AIMS

Systemic sclerosis (SSc) is a systemic autoimmune disease, characterized by widespread microvasculopathy and fibrosis. Vascular and endothelial cell changes appear to precede other features of SSc. Retinal vascular analysis is a new, easy-to-use tool for the assessment of retinal microvascular function. The primary aim of this study was to investigate whether retinal microcirculation is affected in patients with SSc compared to healthy controls.

METHODS

Microvascular function was assessed non-invasively measuring flicker-light induced vasodilation of retinal arterioles (FIDart%). In addition, FID of retinal venules (FIDven%), central retinal arteriolar and venular equivalents (CRAE and CRVE), and measurements of flow-mediated vasodilation (FMD) of the brachial artery, pulse wave velocity (PWV) and pulse wave analysis were obtained. Patients with SSc were prospectively enrolled in the study (n = 40, mean age 56 ± 11 years, females 73 %) and compared with age- and sex-matched healthy controls (HC, n = 40; mean age 59 ± 15 years, females 73 %).

RESULTS

Patients with SSc showed significant impairment of retinal microvascular function compared to age- and gender-matched HC (FIDart%: 2.23 ± 2.0 % vs. 3.1 ± 1.9 %, respectively, p = 0.04). FMD and PWV were not significantly different between the groups. Impaired retinal microvascular function was associated with SSc disease duration.

CONCLUSION

Our study shows a significant impairment of retinal microvascular function in patients with SSc. Because this association seems to be independent of CV risk and dependent on disease duration, retinal vessel analysis may have the potential to serve as a tool for risk assessment and prognosis.

Endothelin-1 as a Candidate Biomarker of Systemic Sclerosis: A GRADE-Assessed Systematic Review and Meta-Analysis With Meta-Regression

Background

There is an ongoing search for novel biomarkers of vascular dysfunction, extent of fibrosis and organ involvement in systemic sclerosis (SSc).

Objectives

We critically appraised the studies investigating the circulating concentrations of endothelin-1 in SSc patients and healthy controls.

Design

This was a systematic review with meta-analysis.

Data sources and methods

We searched electronic databases (PubMed, Scopus, and Web of Science) from inception to 15 June 2024. We assessed the risk of bias and the certainty of evidence using the JBI Critical Appraisal Checklist and GRADE, respectively.

Results

Endothelin-1 concentrations were significantly higher in SSc patients than in controls (26 studies; standardised mean difference, SMD = 0.98, 95% CI 0.73-1.23, P < .001; moderate certainty of evidence). In SSc patients, there were no significant differences in endothelin-1 concentrations between those with limited and diffuse cutaneous SSc (10 studies; SMD = 0.32, 95% CI -0.07 to 0.71 P = .11; very low certainty), and with and without digital ulcers (5 studies; SMD = 0.82, 95% CI -0.06 to 1.69, P = .066; very low certainty), pulmonary arterial hypertension (7 studies; SMD = 0.22, 95% CI -0.01 to 0.45, P = .066; very low certainty) or interstitial lung disease (3 studies; SMD = 0.09, 95% CI -0.18 to 0.35, P = .51; very low certainty). There was limited evidence in SSc patients with different video capillaroscopy pattern and telangiectasias. Subgroup and meta-regression analyses showed significant associations between the effect size and geographical location (studies investigating SSc patients and controls), year of publication (studies investigating SSc patients with limited and diffuse cutaneous SSc), and biological matrix assessed (studies investigating SSc patients with and without digital ulcers).

Conclusion

The results of this systematic review and meta-analysis highlight the potential role of endothelin-1 as a candidate biomarker of SSc. Further research is warranted to determine the utility of measuring endothelin-1 in SSc subgroups with different extent of fibrosis and organ involvement.

Registration

PROSPERO registration number - CRD42024566461.

Vascular endothelial growth factor as a potential biomarker in systemic sclerosis: a systematic review and meta-analysis

Introduction

Systemic sclerosis (SSc), a chronic autoimmune condition, is characterized by microvascular dysfunction, ineffective angiogenesis, and fibrosis. The identification of robust biomarkers reflecting these processes may assist in clinical management and lead to the discovery of new therapies. We sought to address this issue by conducting a systematic review and meta-analysis of studies investigating one such biomarker, vascular endothelial growth factor (VEGF), in SSc patients and healthy controls and in SSc patients with localized or diffuse disease, different video capillaroscopy patterns (early, active, or late), and presence or absence of complications.

Methods

We searched PubMed, Scopus, and Web of Science from inception to 15 May 2024. We assessed the risk of bias and the certainty of evidence using the JBI checklist for analytical studies and GRADE, respectively.

Results

In 42 eligible studies, compared to controls, patients with SSc had significantly higher plasma or serum VEGF concentrations (standard mean difference, SMD=0.93, 95% CI 0.71 to 1.15, p<0.001; moderate certainty). In further analyses, VEGF concentrations were significantly higher in SSc patients with diffused disease than those with localized disease (SMD=0.30, 95% CI 0.01 to 0.59, p=0.046; very low certainty), in patients with late vs. active video capillaroscopy pattern (SMD=0.35, 95% CI 0.09 to 0.61, p=0.008; very low certainty), and in patients with pulmonary hypertension than those without (SMD=0.93, 95% CI 0.34 to 1.53, p=0.002; very low certainty). By contrast, no significant differences were observed between SSc patients with and without digital ulcers, interstitial lung disease, and telangiectasias, whereas limited evidence was available for alveolitis. Meta-regression and subgroup analysis of studies investigating VEGF in SSc patients and controls showed no significant associations between the effects size and various patient and study characteristics, including SSc duration and use of corticosteroids, immunosuppressors and vasodilators. By contrast, significant associations were observed with the geographical location where the study was conducted.

Discussion

The results of this systematic review and meta-analysis suggest that VEGF can be useful in the assessment and management of SSc and in the identification of novel therapeutic strategies in this patient group.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero, identifier CRD42024552925.

Progression, Management, and Outcome of Aortic Valve Stenosis in Systemic Sclerosis: A Case Series

BACKGROUND

In systemic sclerosis (SSc), cardiac involvement is frequent, heterogeneous, and related to a poor prognosis. Due to a longer life expectancy, the development of degenerative aortic stenosis (AS) is not uncommon. The aim of this article is to report the characteristics of AS in SSc, analyzing the rate of progression, the management, and the outcome.

METHODS

This is a case series conducted at the Department of Cardiology of Monaldi Hospital, Naples, Italy.

RESULTS

From January 2007 to December 2022, we analyzed 234 patients with SSc. Ten/234 patients (4.3%) showed severe AS and were included in the analysis (age 75.5 years [IQR 58-84], nine females). Nine had limited and one diffuse SSc. Two patients were in NHYA/WHO II and eight in NYHA/WHO III. All had degenerative three-leaflet AS. Two patients showed severe AS at the first evaluation, and eight developed severe AS during the follow-up, with a time progression from moderate to severe AS of 3.2 ± 1.1 years (progression rate -0.190 ± 0.012 cm2/year for aortic valve area, 8.6 ± 6.1 mmHg/year for mean aortic gradient, 16 ± 7 mmHg/year for peak aortic gradient, and 0.5 ± 0.3 m/s/year for aortic peak velocity). Seven out of 10 patients underwent transcatheter aortic valve implantation (TAVI), one underwent surgical aortic valve replacement (SAVR), one was left untreated, and one was on a waiting list for TAVI. No major complications after TAVI or SAVR occurred. At a mean follow-up of 5.9 ± 3.9 years, eight patients are alive and two died.

CONCLUSION

Severe AS is a relevant cardiac complication of SSc and must be considered in the screening and during the follow-up. Its rapid progression rate may tentatively be due to autoimmunity, degenerative burden, and chronic inflammation.

Circulating cell adhesion molecules in systemic sclerosis: a systematic review and meta-analysis

Introduction

Patients with systemic sclerosis (SSc) have an increased risk of endothelial dysfunction, atherosclerosis, and cardiovascular events compared to the general population. Therefore, the availability of robust circulating biomarkers of endothelial dysfunction and atherogenesis may facilitate early recognition and management of cardiovascular risk in SSc. We sought to address this issue by conducting a systematic review and meta-analysis of studies investigating various types of circulating cell adhesion molecules involved in endothelial dysfunction and atherogenesis (i.e., immunoglobulin-like vascular cell, VCAM-1, intercellular, ICAM-1, platelet endothelial cell, PECAM-1, neural cell, NCAM, Down syndrome cell, DSCAM, and endothelial cell-selective, ESAM, adhesion molecules, E-, L-, and P-selectin, integrins, and cadherins) in SSc patients and healthy controls.

Methods

We searched PubMed, Scopus, and Web of Science from inception to 1 May 2024. Risk of bias and certainty of evidence were assessed using validated tools.

Results

In 43 eligible studies, compared to controls, patients with SSc had significantly higher plasma or serum concentrations of ICAM-1 (standard mean difference, SMD=1.16, 95% CI 0.88 to 1.44, p<0.001; moderate certainty), VCAM-1 (SMD=1.09, 95% CI 0.72 to 1.46, p<0.001; moderate certainty), PECAM-1 (SMD=1.65, 95% CI 0.33 to 2.98, p=0.014; very low certainty), E-selectin (SMD=1.17, 95% CI 0.72 to 1.62, p<0.001; moderate certainty), and P-selectin (SMD=1.10, 95% CI 0.31 to 1.90, p=0.007; low certainty). There were no significant between-group differences in L-selectin concentrations (SMD=-0.35, 95% CI -1.03 to 0.32, p=0.31; very low certainty), whereas minimal/no evidence was available for cadherins, NCAM, DSCAM, ESAM, or integrins. Overall, no significant associations were observed between the effect size and various patient and study characteristics in meta-regression and subgroup analyses.

Discussion

The results of this systematic review and meta-analysis suggest that specific circulating cell adhesion molecules, i.e., ICAM-1, VCAM-1, PECAM-1, E-selectin, and P-selectin, can be helpful as biomarkers of endothelial dysfunction and atherogenesis in the assessment of cardiovascular risk in SSc patients.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42024549710.

Silica's silent threat: Contributing to skin fibrosis in systemic sclerosis by targeting the HDAC4/Smad2/3 pathway

Nowadays, silica products are widely used in daily life, especially in skin applications, which inevitably increases the risk of silica exposure in general population. However, inadequate awareness of silica's potential hazards and lack of self-protection are of concern. Systemic sclerosis (SSc) is characterized by progressive tissue fibrosis under environmental and genetic interactions. Silica exposure is considered an important causative factor for SSc, but its pathogenesis remains unclear. Within this study, we showed that lower doses of silica significantly promoted the proliferation, migration, and activation of human skin fibroblasts (HSFs) within 24 h. Silica injected subcutaneously into mice induced and exacerbated skin fibrosis. Notably, silica increased histone deacetylase-4 (HDAC4) expression by inducing its DNA hypomethylation in normal HSFs. The elevated HDAC4 expression was also confirmed in SSc HSFs. Furthermore, HDAC4 was positively correlated with Smad2/3 phosphorylation and COL1, α-SMA, and CTGF expression. The HDAC4 inhibitor LMK235 mitigated silica-induced upregulation of these factors and alleviated skin fibrosis in SSc mice. Taken together, silica induces and exacerbates skin fibrosis in SSc patients by targeting the HDAC4/Smad2/3 pathway. Our findings provide new insights for evaluating the health hazards of silica exposure and identify HDAC4 as a potential interventional target for silica-induced SSc skin fibrosis.

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.

What have we learned on pre, very early, and early systemic sclerosis microcirculatory pathophysiology? A scoping review

OBJECTIVE

Microvascular dysfunction is an early event in the pathogenesis of systemic sclerosis (SSc). The objective of this scoping review is to update the current information and the level of knowledge about the mechanisms of microvascular dysfunction in pre-SSc, very early diagnosis of SSc (VEDOSS) and early SSc.

METHODS

A PubMed® database search allowed us to include original data from full-length articles in English in which the main topic was microvascular dysfunction in pre-SSC, VEDOSS or early SSc. Data was extracted using a customized form.

RESULTS

In the present review 437 articles were identified, and 42 studies included, reporting data from a total of 1069 patients with pre-SSc, VEDOSS or early-SSc. Distinct mechanisms of microvascular injury were identified comprising, angiogenesis and vasculogenesis, cell surface proteins and adhesion, molecules expression, cytokines profile, inflammatory and oxidation pathways, and skin perfusion determinants. Most of the studies were conducted in early SSc, with a reduced number in pre-disease stages, in which the prompt recognition of specific mechanisms and biomarkers may allow targeted treatment to prevent disease progression.

CONCLUSIONS

Although different molecular expression patterns and signaling pathways related to microvascular dysfunction in pre-SSc, VEDOSS, and early SSc were identified, additional prospective longitudinal studies and combined work with functional evaluation of peripheral skin perfusion are needed.

Systemic Sclerosis-Associated Pulmonary Arterial Hypertension: From Bedside to Bench and Back Again

Systemic sclerosis (SSc) is a heterogeneous disease characterized by autoimmunity, vasculopathy, and fibrosis which affects the skin and internal organs. One key aspect of SSc vasculopathy is pulmonary arterial hypertension (SSc-PAH) which represents a leading cause of morbidity and mortality in patients with SSc. The pathogenesis of pulmonary hypertension is complex, with multiple vascular cell types, inflammation, and intracellular signaling pathways contributing to vascular pathology and remodeling. In this review, we focus on shared molecular features of pulmonary hypertension and those which make SSc-PAH a unique entity. We highlight advances in the understanding of the clinical and translational science pertinent to this disease. We first review clinical presentations and phenotypes, pathology, and novel biomarkers, and then highlight relevant animal models, key cellular and molecular pathways in pathogenesis, and explore emerging treatment strategies in SSc-PAH.

Association between systemic sclerosis and risk of cerebrovascular and cardiovascular disease: a meta-analysis

We aimed to evaluate the association between systemic sclerosis (SSc) and major cerebrovascular/cardiovascular risks through a systematic approach. Databases were systematically searched from their inception to October 10, 2023 for studies comparing cerebrovascular/cardiovascular event rates between patients with SSc and controls. The primary outcome was the stroke risk in patients with SSc. Secondary outcomes included risk of myocardial infarction (MI), cardiovascular disease (CVD), peripheral vascular disease (PVD), and venous thromboembolism (VTE). Seventeen studies with 6,642,297 participants were included. SSc was associated with a significantly increased risk of stroke (HR, 1.64; 95% confidence interval [CI], 1.35-2.01), CVD (HR, 2.12; 95% CI, 1.36-3.3), MI (HR, 2.15; 95% CI, 1.23-3.77), VTE (HR, 2.75; 95% CI, 1.77-4.28), and PVD (HR, 5.23; 95% CI, 4.25-6.45). Subgroup analysis revealed a significantly increased stroke risk in the non-Asian group (HR, 1.55; 95% CI, 1.26-1.9), while the Asian group displayed a higher but not statistically significant risk (HR, 1.86; 95% CI, 0.97-3.55). The study found that SSc is associated with a significantly increased risk of cerebrovascular/cardiovascular events. These findings highlight the importance of vasculopathy in SSc and suggest the need for enhanced clinical monitoring and preventive measures in this high-risk population.

Fibroblasts and Endothelial Cells in Three-Dimensional Models: A New Tool for Addressing the Pathogenesis of Systemic Sclerosis as a Prototype of Fibrotic Vasculopathies

Two-dimensional in vitro cultures have represented a milestone in biomedical and pharmacological research. However, they cannot replicate the architecture and interactions of in vivo tissues. Moreover, ethical issues regarding the use of animals have triggered strategies alternative to animal models. The development of three-dimensional (3D) models offers a relevant tool to investigate disease pathogenesis and treatment, modeling in vitro the in vivo environment. We aimed to develop a dynamic 3D in vitro model for culturing human endothelial cells (ECs) and skin fibroblasts, simulating the structure of the tissues mainly affected in systemic sclerosis (SSc), a prototypical autoimmune fibrotic vasculopathy. Dermal fibroblasts and umbilical vein ECs grown in scaffold or hydrogel, respectively, were housed in bioreactors under flow. Fibroblasts formed a tissue-like texture with the deposition of a new extracellular matrix (ECM) and ECs assembled tube-shaped structures with cell polarization. The fine-tuned dynamic modular system allowing 3D fibroblast/EC culture connection represents a valuable model of the in vivo interplay between the main players in fibrotic vasculopathy as SSc. This model can lead to a more accurate study of the disease's pathogenesis, avoiding the use of animals, and to the development of novel therapies, possibly resulting in improved patient management.