Mechanisms of vascular damage in systemic sclerosis

Could Gas6/TAM Axis Provide Valuable Insights into the Pathogenesis of Systemic Sclerosis?

Systemic sclerosis (SSc) is a connective tissue disorder characterized by microvascular injury, extracellular matrix deposition, autoimmunity, inflammation, and fibrosis. The clinical complexity and high heterogeneity of the disease make the discovery of potential therapeutic targets difficult. However, the recent progress in the comprehension of its pathogenesis is encouraging. Growth Arrest-Specific 6 (Gas6) and Tyro3, Axl, and MerTK (TAM) receptors are involved in multiple biological processes, including modulation of the immune response, phagocytosis, apoptosis, fibrosis, inflammation, cancer development, and autoimmune disorders. In the present manuscript, we review the current evidence regarding SSc pathogenesis and the role of the Gas6/TAM system in several human diseases, suggesting its likely contribution in SSc and highlighting areas where further research is necessary to fully comprehend the role of TAM receptors in this condition. Indeed, understanding the involvement of TAM receptors in SSc, which is currently unknown, could provide valuable insights for novel potential therapeutic targets.

Hypoxia-Inducible Factor-1α (HIF-1α) as a Biomarker for Changes in Microcirculation in Individuals with Systemic Sclerosis

INTRODUCTION

Systemic sclerosis is an autoimmune disease characterized by tissue fibrosis and microangiopathy. Vascular changes such as a decrease in capillary density diminish blood flow and impair tissue oxygenation. Reliable ways to monitor disease activity and predict disease progression are desired in the process of patient selection for clinical trials and to optimize individual patient outcomes. Hypoxia-inducible factor-1 (HIF-1) is a dimeric protein complex that plays an integral role in the body's response to hypoxia. Our study aimed to investigate the potential abnormalities of HIF-1α plasma concentration and its possible association with disease activity and vascular abnormalities in patients with systemic sclerosis.

METHODS

Blood plasma levels of HIF-1α were measured in patients with systemic sclerosis (n = 50) and in healthy individuals (n = 30) using commercially available ELISA test kits.

RESULTS

The results showed a marked increase in HIF-1α levels in patients with systemic sclerosis (3.042 ng/ml [2.295-7.749]) compared to the control group (1.969 ng/ml [1.531-2.903] p < 0.01). Patients with diffuse cutaneous SSc (2.803 ng/ml, IQR 2.221-8.799) and limited cutaneous SSc (3.231 ng/ml, IQR 2.566-5.502) exhibited elevated serum HIF-1α levels compared to the control group (p < 0.01). We found a notable increase in HIF-1α plasma concentration in patients with an "active" pattern (6.625 ng/ml, IQR 2.488-11.480) compared to those with either an "early" pattern (2.739, IQR 2.165-3.282, p < 0.05) or a "late" pattern (2.983 ng/ml, IQR 2.229-3.386, p < 0.05). Patients with no history of digital ulcers had significantly higher levels of HIF-1α (4.367 ng/ml, IQR 2.488-9.462) compared to patients with either active digital ulcers (2.832 ng/ml, IQR 2.630-3.094, p < 0.05) or healed digital ulcers (2.668 ng/ml, IQR 2.074-2.983, p < 0.05).

CONCLUSIONS

Our results indicate that HIF-1α may serve as a biomarker in assessing microcirculatory changes in individuals with systemic sclerosis.

Effect of season on clinical outcomes of Thai systemic sclerosis: Analysis of the Thai national healthcare database

Objectives: We aimed to determine rate of admission, mortality rate, and causes of death in systemic sclerosis (SSc) patients after stratifying by season.Method: A cross-sectional analysis was performed of patients over 15 in the national database with a primary diagnosis of SSc (ICD-10:M34) covered by the National Health Security Office hospitalized between 2014 and 2018. The seasons were stratified into hot, rainy, and Cool dry seasons.Results: Included were 2480 SSc patients with 3684 admissions: most (64.3%) were female. The respective mean age and median length of stay was 56.9 ± 12.3 years and 3 days (IQR 2-6). The admission rate was highest during the rainy season (1574 visits, 42.7%), followed by the cool dry season (1183 visits, 32.1%) then the hot season (927 visits, 25.2%). During the 13,180 person-days, 1660 SSc patients died resulting in a mortality rate of 12.1 per 100 person-days. The proportion of SSc patients who died in the Cool dry season was significantly higher than in the hot or rainy season (p = .04). Pulmonary involvement in SSc was the most common cause of death in the hot season, which is greater than in the other seasons (p = .004). By comparison, death due to cardiac involvement in SSc was common during the rainy season and cool dry seasons (p = .04).Conclusion: The admission rate among Thai SSc patients was greatest during the rainy season, while mortality was highest during the cool dry season. The most common causes of death were SSc-related irrespective of season, particularly cardiopulmonary involvement.

The effects of a single carbon dioxide and hot water hand bath on acral perfusion in systemic sclerosis: A randomized, clinical study

Secondary Raynaud's phenomenon is the most common manifestation of systemic sclerosis, affecting more than 99% of systemic sclerosis patients, and a major cause of morbidity. Frequent and prolonged secondary Raynaud's phenomenon attacks not only cause severe discomfort and pain but also ischemic acral tissue damage. In addition to vasoactive drugs, carbon dioxide (CO2) hand bath and hot water bath are potential non-pharmacological treatment options which can be self-administered by affected patients at any time. In order to compare the efficacy of these two physical measures, this randomized, clinical study evaluated the effects of a single CO2 hand bath in patients with systemic sclerosis and secondary Raynaud's phenomenon and a healthy control group versus a single hot water hand bath on acral perfusion in systemic sclerosis by Doppler ultrasonography. None of the patients had currently digital ulcers, a vasoactive medication or a concomitant vascular disease. CO2 immersion induced an acute hemodynamic response, whereas hot water immersion had no significant effect on acral perfusion in systemic sclerosis.

Bone mineral density and microarchitecture linkages with micro- and macro-vascular impairments at the hand in systemic sclerosis: an HRpQCT study

Objective

To investigate the link between bone alteration and micro- and macro-vascular disease in patients with systemic sclerosis (SSc).

Results

33 SSc patients were included. In univariate analysis, low values of cortical vBMD were significantly associated with a low DBI at the 2nd finger (p = 0.004) and at the 4th (p = 0.002) and with severe capillaroscopic score (p = 0.008). In multivariate analyses, low cortical vBMD was associated with a low DBI at the 4th finger, age and severe capillaroscopic score (adjusted R² = 0.58; p = < 0.001). Low cortical thickness was associated with a low DBI at the 4th finger, severe capillaroscopic score and age (adjusted R² = 0.49, p = < 0.001).

Conclusion

Our study findings showed an association between micro- and macro-vessel damage and altered microarchitectural indices at the radius in SSc.

Methods

We performed a pilot study in female patients with SSc. Microvascular disease was assessed by the capillaroscopic score of Cutolo. Macrovascular involvement was measured by digito-brachial pressure index (DBI) on laser-Doppler at the 2nd and 4th finger. Volumetric bone mineral density (vBMD) and bone microarchitecture involvement were analysed by High-Resolution peripheral Quantitative Computed Tomography (HRpQCT) at the distal radius.

Short course of simvastatin has no effect on markers of endothelial activation in normolipidemic patients with systemic sclerosis

Objective

Statins, a class of 3-hydroxy-3 methyl-glutaryl-coenzyme A reductase inhibitors, are widely used for the treatment of atherosclerosis. Less is known about the role of statins in the treatment of vascular complication in systemic sclerosis (SSc). We therefore performed a short-term interventional study with simvastatin in patients with the diffuse variant of SSc and normal lipid profiles.

Methods

Twenty-five patients with diffuse SSc were enrolled and received simvastatin at a daily dose of 20 mg for 28 days. Soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1) and soluble P-, E- and L-selectins were assessed by ELISA prior to treatment and at day 28.

Results

No statistically significant changes in the levels of adhesion molecules were observed: sICAM-1 1011 vs. 1032 ng/mL, sVCAM-1 1225 vs. 1570 ng/mL, sP-selectin 66.7 vs. 66.0 ng/mL, sE-selectin 276 vs. 253 ng/mL and sL-selectin 887 vs. 927 ng/mL prior to treatment and at day 28, respectively.

Conclusions

Markers characterizing vascular activation were not affected by short treatment with low-dose simvastatin in SSc patients, indicating that the endothelial-protective effect of statins may be related to treatment duration and dose.

Review of local wound management for scleroderma-associated digital ulcers

Digital ulcers (DU) are a common clinical problem in systemic sclerosis (SSc); however, there is no standardization of local wound care protocols for management of these lesions. There is a well-recognized need to develop and standardize non-pharmacological management of DU in patients with SSc, and to adopt these protocols in future clinical trials that focus on DU healing. The purpose of this review is to outline the types of DU that occur in SSc, and provide an update on the principles of wound management for these lesions based on the current literature and expert opinion.

Systemic Sclerosis and the Gastrointestinal Tract-Clinical Approach

Systemic sclerosis (SSc) is a multisystem disease characterized by functional and structural abnormalities of small blood vessels, fibrosis of the skin and internal organs, immune system activation, and autoimmunity. The gastrointestinal tract is involved in nearly all patients and is a source of significant morbidity and even mortality. The aim of this review is to summarize the pathogenesis and to provide a clinical approach to these patients.

Contribution of CD8+ T cells to inflammatory cytokine production in systemic sclerosis (SSc)

Only limited attention has been paid to the role of CD8 + T cells in the etiopathogenesis and progression of systemic sclerosis (SSc). CD8 + T cells may have autoantigen-specific and pro-inflammatory but also immunomodulatory properties. To investigate the differentiation of CD8 + T cells, staining of cell surface factors and of chemokine receptors were performed. In addition, the cytokine-producing ability of circulating CD8 + T cells and their sensitivity to suppression by regulatory T cells (Tregs) were compared between patients with diffuse (dcSSc) or limited cutaneous SSc (lcSSc) and healthy individuals. We identified CD8 + T cells as producers of pro-inflammatory type-2 cytokines with a significant contribution of memory CD8 + T cells. Memory CD8 + T cells of SSc patients stayed unaltered after suppression with autologous Tregs. Expression of chemokine receptors was significantly correlated with intracellular cytokine production in CD8 + T cells with a clear dichotomy of type 1 and type 2 cytokines. High levels of intracellular cytokines, such as interleukin-(IL)-4, IL-13 and tumor-necrosis-factor-alpha (TNFalpha) were positively associated with the presence of Scl-70 or anti-centromere antibodies and negatively with the administration of glucocorticoids. Administration of glucocorticoids was positively associated with higher IFNgamma production. Lack of anti-centromere antibodies and therapy with methotrexate were positively associated with higher intracellular IL-10 production. CD8 + T cells may significantly contribute to inflammation in SSc. Our findings suggest to not only focus on T helper cells in the development of therapeutic strategies but also to consider the role of CD8 + T cells in the etiopathogenesis and perpetuation of SSc.

Early Endothelial Progenitor Cells (eEPCs) in systemic sclerosis (SSc) - dynamics of cellular regeneration and mesenchymal transdifferentiation

BACKGROUND

Patients with systemic sclerosis (SSc) are endagered by tissue fibrosis and by microvasculopathy, with the latter caused by endothelial cell expansion/proliferation. SSc-associated fibrosis potentially results from mesenchymal transdifferentiation of endothelial cells. Early Endothelial Progenitor Cells (eEPCs) act proangiogenic under diverse conditions. Aim of the study was to analyze eEPC regeneration and mesenchymal transdifferentiation in patients with limited and diffuse SSs (lSSc and dSSc).

METHODS

Patients with both, lSSc and dSSc were included into the study. The following parameters were evaluated: eEPC numbers and regeneration, concentrations of vasomodulatory mediators, mesenchymal properties of blood-derived eEPC. Serum samples of healthy subjects and SS patients were used for stimulation of cultured human eEPC, subsequently followed by analysis of mesenchymal cell characteristics and mobility.

RESULTS

Twenty-nine patients were included into the study. Regenerative activity of blood-derived eEPCs did not differ between Controls and patients. Circulating eEPC were significantly lower in all patients with SSc, and in limited and diffuse SSc (lSSc/dSSc). Serum concentrations of promesenchymal TGF-b was elevated in all patients with SSc. Cultured mononuclear cells from SS patients displayed higher abundances of CD31 and of CD31 and aSMA combined. Finally, serum from SSc patients inhibited migration of cultured eEPCs and the cells showed lower sensitivity towards the endothelin antagonist Bosentan.

CONCLUSIONS

The eEPC system, which represents an essential element of the endogenous vascular repair machinery is affected in SSc. The increased appearance of mesenchymal properties in eEPC may indicate that alterations of the cells potentially contribute to the accumulation of connective tissue and to vascular malfunction.

Secondary vasculitis in autoimmune connective tissue diseases

PURPOSE OF REVIEW

The current review of the vasculitis associated with autoimmune connective tissue diseases is very appropriate and timely, in view of the recently acquired expanding knowledge, over the last decade, on the clinical epidemiology, pathophysiology, and the innovative therapeutic strategies. This review will specifically focus on the clinical presentations of secondary vasculitides, pathophysiology, and their management.

RECENT FINDINGS

New knowledge on the immunological triggers and pathophysiology of these conditions, in relation to various infections and airborne substances are discussed apart from the novel targeted immunotherapy, which has a direct effect on the outcome and reduction of iatrogenic complications.

IN SUMMARY

The review will inform the classical nature and pattern of vasculitis secondary to autoimmune diseases with specific reference to targeted immunotherapy.

Systemic sclerosis: The need for structured care

Autoimmune connective tissue diseases (CTDs) have a propensity to affect multiple organ systems as well as physical function, quality of life, and survival. Their clinical heterogeneity, multisystem involvement, and low worldwide prevalence present challenges for researchers to establish a study design to help better understand the course and outcomes of CTDs. Systemic sclerosis (SSc) is a notable example of a CTD, wherein longitudinal cohort studies (LCS) have enabled us to elucidate disease manifestations, disease course, and risk and prognostic factors for clinically important outcomes, by embedding research in clinical practice. Nevertheless, further efforts are needed to better understand SSc especially with regard to recognizing organ involvement early, developing new therapies, optimizing the use of existing therapies, and defining treatment targets. The heterogeneous multi-organ nature of SSc would lend itself well to a structured model of care, wherein step-up treatment algorithms are used with the goal of attaining a prespecified treatment target. In this chapter, we discuss the rationale for a structured treatment approach in SSc and propose possible treatment algorithms for three of the more common disease manifestations, namely skin involvement, digital ulcers and gastrointestinal tract involvement. We discuss possible strategies for evaluating and implementing these algorithms in the setting of LCS. We conclude by presenting a research agenda for the development of structured models of care in SSc.

A review of the effects of statins in systemic sclerosis

OBJECTIVES

We performed a literature review assessing possible benefits of statins in systemic sclerosis (SSc).

METHODS

PubMed, Embase, Cochrane Databases, and Medline were searched. Full-text English publications were identified in which the effects of statins in SSc were examined. Letters, review articles, and studies on morphea were excluded.

RESULTS

In all, 18 of 404 studies were relevant. In vitro, statins decreased transcription and translation of IL-6 and collagen, with reversal via mevalonate. Animal studies demonstrated reduced production of Ras (a protein superfamily of GTPases), Rho (part of the Ras superfamily), and extracellular signal-regulated kinases (ERK), less fibrosis and myofibroblast transdifferentiation, and improved macrovasculature. In human studies, IL-6, an inflammatory cytokine, was reduced. Usually endothelial progenitor cell concentrations increased, and flow-mediated dilatation improved. Raynaud's phenomenon, digital ulcers, and physician global assessments improved in the majority of studies of statin treatment in SSc. None of the 256 patients receiving statins experienced transaminitis or myopathy.

CONCLUSIONS

Not all findings were consistent. However, in general, in vitro, animal, and human studies demonstrated benefit in SSc pathophysiology, likely mediated through inhibition of lipid intermediate synthesis. Clinical improvement in SSc circulatory complications was observed. Statins seemed safe and well tolerated in SSc. Larger longer-term multi-site randomized trials are needed to further determine the role of statins as adjunctive treatment of this complex, heterogeneous connective tissue disease.

The right ventricle in scleroderma (2013 Grover Conference Series)

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

Update on etiopathogenesis of systemic sclerosis

Systemic Sclerosis (SSc) is an autoimmune disease of multifactorial etiology, triggered by a combination of genetic and environmental factors. Its varied clinical expression results from the complex physiopathogenic interaction of three main elements: proliferative vasculopathy, immune dysregulation and abnormal deposition and remodeling of the extracellular matrix (ECM), of which the characteristic disease fibrosis is the result. Early physiopathogenic events appear to be endothelial injury and imbalance in vascular repair with the activation of endothelial cells, the immune system and platelets, with the release of multiple mediators such as TH2 proinflammatory cytokines and growth factors, triggering a sequence of simultaneous or cascading events that involve several intracellular signaling pathways. The most important result of these events is the hyperactivation of fibroblasts, the main effector cells of fibrosis, which will then produce large amounts of ECM constituents and secrete multiple growth factors and cytokines that perpetuate the process. In this article we review the main factors potentially involved in the etiology of SSc and reexamine the current knowledge about the most important mechanisms involved in the development of lesions that are characteristic of the disease. A better understanding of these physiopathogenic mechanisms will help identify potential therapeutic targets, which may result in advances in the management of this complex and debilitating disease.

MicroRNA-29a induces apoptosis via increasing the Bax:Bcl-2 ratio in dermal fibroblasts of patients with systemic sclerosis

The most prominent feature of systemic sclerosis (SSc) and other diseases associated with fibrosis is the prolonged activation of fibroblasts not eliminated by apoptosis, hence characterized by accumulation of more extra cellular matrix (ECM). We tend to verify if microRNA-29a (miR-29a) as an anti-fibrotic factor could induce apoptosis in SSc fibroblasts. We did not detect apoptosis in SSc fibroblasts. We found that Bcl-2 expression was upregulated in SSc fibroblasts and the ratio of Bax:Bcl-2 in these cells was significantly lower (p = 0.02) compared to normal fibroblasts. Transfection of both SSc and transforming growth factor-β (TGF-β) stimulated fibroblasts by miR-29a mimic, significantly decreased the expression of two anti-apoptotic members of the Bcl-2 family, Bcl-2 (p = 0.0005, p = 0.01) and Bcl-XL (p = 0.0001, p = 0.006), resulted in enhanced Bax:Bcl-2 ratio and induced a high rate of apoptosis. Recently, miR-29 has been introduced as an anti-fibrotic factor with potential therapeutic effect on SSc. Until now, it has not been proposed whether there is a relationship between miR-29a and apoptosis in SSc. According to our results, it seems that miR-29a is a potent inducer of apoptosis in SSc fibroblasts and an attenuator of ECM production in these cells. MiR-29a disrupted the expression profiling of Bcl-2 family proteins (Bax, Bcl-2 and Bcl-XL) which is the central point of dynamic life-death rheostat in many apoptotic pathways. Furthermore, dermal fibroblasts from patients with SSc showed elevation in TNF-α mRNA levels, while restoration of miR-29a decreases TNF-α production in these cells. Although further molecular studies are necessary to investigate the underlying apoptotic pathways, the present findings suggest that anti-fibrotic and pro-apoptotic properties of miR-29a could provide novel benefits toward the development of fibroblast-specific anti-fibrotic therapies.

Serum levels of soluble carbonic anhydrase IX are decreased in patients with diffuse cutaneous systemic sclerosis compared to those with limited cutaneous systemic sclerosis

Hypoxia may play an important role in the pathogenesis of systemic sclerosis (SSc). Carbonic anhydrase IX (CA IX) is one of the hypoxia markers and its extracellular domain can be released into the serum. However, the clinical significance of serum CA IX levels in SSc is still unknown. The aim of this study is to evaluate the possibility that serum CA IX levels can be a specific disease marker of SSc. Serum samples were obtained from SSc patients and healthy controls. Patients diagnosed as scleroderma spectrum disorder (SSD), who did not fulfill the ACR criteria of SSc but were thought that they might develop SSc in the future, were also included in this study. Serum CA IX levels were measured with specific enzyme-linked immunosorbent assays. SSD patients had significantly lower CA IX levels than diffuse cutaneous SSc (dcSSc), limited cuntaneous SSc (lcSSc) and healthy control groups. Also, we found a significant decrease in the values in dcSSc patients compared to those of lcSSc patients. Serum levels of CA IX may be useful for the differentiation of lcSSc from SSD. Decreased serum CA IX levels in spite of the presence of hypoxia in SSc may indicate an impaired response to hypoxia, which leads to the persistent hypoxic condition. Our results suggest that the abnormal response to hypoxia may already exist in SSD patients, and may be involved in its pathogenesis.

The local complement activation on vascular bed of patients with systemic sclerosis: a hypothesis-generating study

Objective

The role of complement system in the pathogenesis of systemic sclerosis (SSc) has been debated during the last decade but an evident implication in this disease has never been found. We carried out an explorative study on SSc patients to evaluate the expression of soluble and local C5b-9 complement complex and its relation with a complement regulator, the Membrane Cofactor Protein (MCP, CD46) on skin vascular bed as target distinctive of SSc disease. We also analyzed two polymorphic variants in the complement activation gene cluster involving the MCP region.

Methods

C5b-9 plasma levels of SSc patients and healthy subjects were analyzed by ELISA assay. Archival skin biopsies of SSc patients and controls were subjected to immunofluorescence analysis to detect C5b-9 and MCP on vascular endothelial cells. The expression of MCP was validated by immunoblot analysis with specific antibody. Polymorphic variants in the MCP gene promoter were tested by a quantitative PCR technique-based allelic discrimination method.

Results

Even though circulating levels of C5b-9 did not differ between SSc and controls, C5b-9 deposition was detected in skin biopsies of SSc patients but not in healthy subjects. MCP was significantly lower in skin vessels of SSc patients than in healthy controls and was associated with the over-expression of two polymorphic variants in the MCP gene promoter, which has been related to more aggressive phenotypes in other immune-mediated diseases.

Conclusions

Our results firsty document the local complement activation with an abnormal expression of MCP in skin vessels of SSc patients, suggesting that a subset of SSc patients might be exposed to more severe organ complications and clinical evolution due to abnormal local complement activation.

The role of botulinum toxin in vasospastic disorders of the hand

Raynaud phenomenon may be a primary disorder or associated with a variety of other autoimmune processes. Raynaud phenomenon produces digital vasospasm, which can lead to ischemia and ulceration. The treatment of Raynaud phenomenon has been difficult because multiple medical treatments have not provided uniform resolution of symptoms. Many patients have turned to surgery and sympathectomies for the treatment of unrelenting vasospasm. Botulinum toxin has been shown to be an effective alternative to surgery, with a single treatment being capable of resolving pain and healing ulcer. This article reviews the use of botulinum toxin for the treatment of Raynaud phenomenon.

The association between vibration and vascular injury in rheumatic diseases: a review of the literature

Vascular manifestations can be seen early in the pathogenesis of inflammatory rheumatic diseases. Animal experiments, laboratory and clinical findings indicated that acute or long-term vibration exposure can induce vascular abnormalities. Recent years, in addition to Raynaud's phenomenon (RP), vibration as a risk factor for other rheumatic diseases has also received corresponding considered. This review is concentrated upon the role of vibration in the disease of systemic sclerosis (SSc). In this review, we are going to discuss the main mechanisms which are thought to be important in pathophysiology of vascular injury under the three broad headings of "vascular", "neural" and "intravascular". Aspects on the vibration and vascular inflammation are briefly discussed. And the epidemiological studies related to vibration studies in SSc and other rheumatic diseases are taken into account.

[Assessment of endothelial function in autoimmune diseases]

Numerous autoimmune-inflammatory rheumatic diseases have been associated with accelerated atherosclerosis or other types of vasculopathy leading to an increase in cardiovascular disease incidence. In addition to traditional cardiovascular risk factors, endothelial dysfunction is an important early event in the pathogenesis of atherosclerosis, contributing to plaque initiation and progression. Endothelial dysfunction is characterized by a shift of the actions of the endothelium toward reduced vasodilation, a proinflammatory and a proadhesive state, and prothrombic properties. Therefore, assessment of endothelial dysfunction targets this vascular phenotype using several biological markers as indicators of endothelial dysfunction. Measurements of soluble adhesion molecules (ICAM-1, VCAM-1, E-selectin), pro-thrombotic factors (thrombomodulin, von Willebrand factor, plasminogen activator inhibitor-1) and inflammatory cytokines are most often performed. Regarding the functional assessment of the endothelium, the flow-mediated dilatation of conduit arteries is a non-invasive method widely used in pathophysiological and interventional studies. In this review, we will briefly review the most relevant information upon endothelial dysfunction mechanisms and explorations. We will summarize the similarities and differences in the biological and functional assessments of the endothelium in different autoimmune diseases.

Long-term survival of Japanese patients with pulmonary arterial hypertension treated with beraprost sodium, an oral prostacyclin analogue

OBJECTIVE

Beraprost was developed as the first oral prostacyclin analog to treat patients with pulmonary arterial hypertension (PAH). Although this drug demonstrates improvements in the patient's exercise capacity and symptoms, it carries a weak recommendation in the PAH evidence-based treatment algorithm due to a lack of durability of effects. However, this therapy remains a major treatment method in Japan due to its availability and inexpensive cost. The purpose of this study was to elucidate whether this drug exhibits durable effects on sustained overall survival.

METHODS

A comparison of survival benefits was completed among patients undergoing treatment with beraprost (n=35) or conventional therapy (n=44). In addition, the estimated survival calculated using the equation developed by the National Institutes of Health Registry was used for the analysis.

RESULTS

Although no significant differences were observed between the two groups using the Kaplan-Meier survival curve, a statistical difference was observed between the patients receiving high-dose beraprost therapy (>120 μg) and those receiving conventional therapy (5- and 10-year survival: 71.1% and 49.4% vs. 37.7% and 21.2%, respectively; p=0.0466). Moreover, the cumulative survival rates in the patients receiving beraprost were slightly better than the estimated survival rates. In the PAH patients with connective tissue diseases, a tendency towards better survival outcomes was observed in the group treated with beraprost.

CONCLUSION

This study suggests the survival benefits of high-dose beraprost therapy for patients with PAH. The retrospective nature of this study, however, makes it difficult to conclude definitively that beraprost exerts significant beneficial effects on survival.

Morphometric evaluation of nitric oxide synthase isoforms and their cytokine regulators predict pulmonary dysfunction and survival in systemic sclerosis

Because histopathological changes in the lungs of patients with systemic sclerosis (SSc) are consistent with alveolar and vessel cell damage, we presume that this interaction can be characterized by analyzing the expression of proteins regulating nitric oxide (NO) and plasminogen activator inhibitor-1 (PAI-1) synthesis. To validate the importance of alveolar-vascular interactions and to explore the quantitative relationship between these factors and other clinical data, we studied these markers in 23 cases of SSc nonspecific interstitial pneumonia (SSc-NSIP). We used immunohistochemistry and morphometry to evaluate the amount of cells in alveolar septa and vessels staining for NO synthase (NOS) and PAI-1, and the outcomes of our study were cellular and fibrotic NSIP, pulmonary function tests, and survival time until death. General linear model analysis demonstrated that staining for septal inducible NOS (iNOS) related significantly to staining of septal cells for interleukin (IL)-4 and to septal IL-13. In univariate analysis, higher levels of septal and vascular cells staining for iNOS were associated with a smaller percentage of septal and vascular cells expressing fibroblast growth factor and myofibroblast proliferation, respectively. Multivariate Cox model analysis demonstrated that, after controlling for SSc-NSIP histological patterns, just three variables were significantly associated with survival time: septal iNOS (P=0.04), septal IL-13 (P=0.03), and septal basic fibroblast growth factor (bFGF; P=0.02). Augmented NOS, IL-13, and bFGF in SSc-NSIP histological patterns suggest a possible functional role for iNOS in SSc. In addition, the extent of iNOS, PAI-1, and IL-4 staining in alveolar septa and vessels provides a possible independent diagnostic measure for the degree of pulmonary dysfunction and fibrosis with an impact on the survival of patients with SSc.

Role of endothelial to mesenchymal transition in the pathogenesis of the vascular alterations in systemic sclerosis

The pathogenesis of Systemic Sclerosis (SSc) is extremely complex, and despite extensive studies, the exact mechanisms involved are not well understood. Numerous recent studies of early events in SSc pathogenesis have suggested that unknown etiologic factors in a genetically receptive host trigger structural and functional microvascular endothelial cell abnormalities. These alterations result in the attraction, transmigration, and accumulation of immune and inflammatory cells in the perivascular tissues, which in turn induce the phenotypic conversion of endothelial cells and quiescent fibroblasts into activated myofibroblasts, a process known as endothelial to mesenchymal transition or EndoMT. The activated myofibroblasts are the effector cells responsible for the severe and frequently progressive fibrotic process and the fibroproliferative vasculopathy that are the hallmarks of SSc. Thus, according to this hypothesis the endothelial and vascular alterations, which include the phenotypic conversion of endothelial cells into activated myofibroblasts, play a crucial role in the development of the progressive fibrotic process affecting skin and multiple internal organs. The role of endothelial cell and vascular alterations, the potential contribution of endothelial to mesenchymal cell transition in the pathogenesis of the tissue fibrosis, and fibroproliferative vasculopathy in SSc will be reviewed here.

Acute retinal artery occlusion in systemic sclerosis: a rare manifestation of systemic sclerosis fibroproliferative vasculopathy

OBJECTIVES

To describe three patients with systemic sclerosis (SSc) who developed acute unilateral blindness in the absence of any common etiologic factor for blindness. In one patient, the affected eye required enucleation and was examined histopathologically.

METHODS

Following identification of the first patient with retinal artery occlusion at the Scleroderma Center of Thomas Jefferson University, every patient evaluated at the Center from May 2001 to December 2010 was prospectively assessed for the development of acute unilateral blindness. Two additional cases were identified. Here, we describe the clinical features, laboratory and ancillary examinations of the three patients with SSc who developed acute unilateral blindness and present the histopathological examination of one eye enucleated from one of the patients.

RESULTS

Clinical and angiographic studies were consistent with acute retinal artery occlusion. The histopathological studies showed severe retinal ischemic atrophy and concentric narrowing and fibrosis of small retinal vessels.

CONCLUSIONS

These findings suggest that acute retinal artery occlusion in these patients is a manifestation of the fibroproliferative vasculopathy characteristic of SSc.

Antiendothelial cells antibodies in patients with systemic sclerosis in relation to pulmonary hypertension and lung fibrosis

Although scleroderma is generally considered a fibrosing disease, it is now recognized that the underlying vascular pathology is playing a fundamental role in its pathogenesis. The present study was aimed at testing the prevalence of anti-endothelial cell antibodies (AECA) in systemic scleroderma (SSc) patients with and without pulmonary hypertension (PH) and in relation to the presence of pulmonary fibrosis. Fifty four SSc patients (50 females and 4 male, mean age 55.7 ± 16.3 years) were prospectively screened. All patients underwent transthoracic echocardiography with the estimation of pulmonary artery pressure (PAP) and tricuspid regurgitant peak gradient (TRPG). All patients suspected to have pulmonary hypertension were referred for right heart catheterization. Restrictive lung disease was confirmed by HRCT. A healthy control group included (n = 27; 7 men and 20 women, mean age 49.8 ± 12.1 years). The study of AECA was performed using the indirect immunofluorescence method on commercially available human umbilical vein endothelial cells. The HRCT scans in patients with suspected interstitial lung disease revealed signs of lung fibrosis in 15 (out of the 36 examined patients). TRPG at rest of 31 mmHg was demonstrated in 14 (21%) patients. During cardiac catheterization, arterial PH was found in two patients. Resting venous PH was found in one patient and an excessive post capillary PAP elevation at rest was demonstrated in 11 patients. At the baseline, 14/54 patients (26%) were positive for AECA. In the control group, the frequency of the antibodies was 3/27 (11%). No statistical correlation between antibody titter and the presentation of the disease existed. AECA were highly prevalent in a subgroup of patients suffering from interstitial pulmonary fibrosis. Out of the 15 patients suffering from lung fibrosis, 7 were AECA positive. The presence of AECA correlated very well with antinuclear antibodies (ANA), but was not related to the profile of ANA. Our findings support evidence that endothelial cell damage is involved in SSc, as there was increased prevalence of circulating AECA of the IgG isotype in SSc patients. AECA may also be related to the complications of SSc, like pulmonary fibrosis.

Cardiovascular risk in autoimmune disorders: role of asymmetric dimethylarginine

Mounting evidence indicates that cardiovascular events are a main cause of excessive mortality of autoimmune disorders like type I diabetes mellitus and rheumatic diseases. Inflammation and endothelial dysfunction, independent predictors to cardiovascular disease, are hallmarks of autoimmunity. Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, can cause or contribute to the inflammatory syndrome and endothelial dysfunction. Recently, elevated ADMA levels have been demonstrated in many autoimmune diseases, suggesting that ADMA might play an important role for the associated manifestations of cardiovascular disease. In the review, we discuss the role of ADMA in the excessive cardiovascular morbidity and mortality associated with autoimmune diseases.

Clinical trials with endothelin receptor antagonists: what went wrong and where can we improve?

In the early 1990s, within three years of cloning of endothelin receptors, orally active endothelin receptor antagonists (ERAs) were tested in humans and the first clinical trial of ERA therapy in humans was published in 1995. ERAs were subsequently tested in clinical trials involving heart failure, pulmonary arterial hypertension, resistant arterial hypertension, stroke/subarachnoid hemorrhage and various forms of cancer. The results of most of these trials - except those for pulmonary arterial hypertension and scleroderma-related digital ulcers - were either negative or neutral. Problems with study design, patient selection, drug toxicity, and drug dosing have been used to explain or excuse failures. Currently, a number of pharmaceutical companies who had developed ERAs as drug candidates have discontinued clinical trials or further drug development. Given the problems with using ERAs in clinical medicine, at the Twelfth International Conference on Endothelin in Cambridge, UK, a panel discussion was held by clinicians actively involved in clinical development of ERA therapy in renal disease, systemic and pulmonary arterial hypertension, heart failure, and cancer. This article provides summaries from the panel discussion as well as personal perspectives of the panelists on how to proceed with further clinical testing of ERAs and guidance for researchers and decision makers in clinical drug development on where future research efforts might best be focused.

Progressive capillary loss over a decade in patients with systemic sclerosis, in particular in patients with early digital ischaemic manifestations

OBJECTIVE

Characteristic capillary abnormalities occur early in systemic sclerosis (SSc). Our aim was to study the longitudinal development of capillary density in SSc patients.

METHODS

Forty-eight consecutive patients with SSc fulfilling a follow-up of at least 8 years were retrospectively analysed for capillary loss over the observation period. Eleven had diffuse cutaneous SSc (dcSSc) and 37 limited cutaneous SSc (lcSSc). The median disease duration at first assessment was 2.5 years. Capillary density was determined by direct counting of capillaries in the distal row on eight fingers in a stereo-zoom microscope at 20× magnification.

RESULTS

Capillary density decreased over the observation period in dcSSc (from median 5.1 to 4.4 loops/mm, p < 0.05) and in lcSSc (from 5.1 to 4.2 loops/mm, p < 0.001). No significant difference was found between the two forms at start or at follow-up. Digital ischaemic manifestations had already been found at the first assessment in 19 patients. They did not differ in capillary density from those without ischaemic manifestations at the first assessment (5.0 and 5.3 loops/mm), but did differ at follow-up (3.6 and 4.7 loops/mm, p < 0.001). Capillary loss was more pronounced in patients who already had digital ischaemic manifestations at the first assessment compared to those without (p < 0.02).

CONCLUSION

In SSc, early digital ischaemic manifestations may precede a subsequent progressive capillary loss. The association between capillary loss and serious internal vascular complications remains to be studied.

The pathogenesis of systemic sclerosis revisited

Although infectiological stimuli, environmental factors and genotypic features are known to contribute to the initiation and perpetuation of systemic sclerosis (SSc), its etiology still remains to be enigmatic, and less elusive insights are to be achieved by ongoing and future investigations. Being characterized, however, as chronic autoimmune disease with excessive collagen accumulation in skin, synovia and visceral organs such as lung, heart, and digestive tract along with obliterating angiopathy, the pathophysiology of SSc can be summarized as being based on imbalances of the cellular and humoral immune system, vascular dysfunction and activation of resident connective tissue cells. A complex interplay between these major components manages to establish and maintain the inability of the vasculature to adequately react to the need for dilatation, constriction and growth of new vessels, to cause the increased deposition of extracellular matrix constituents as well as to facilitate immunological disarrangement. Despite parallels to the chicken and egg causality dilemma, all of these account for what later clinicians observe in patients suffering from Raynaud's phenomenon, digital ulcers, sclerodactyly, rigidity of the face, microstomia, sicca syndrome, dyspnea, dry cough, pulmonary hypertension, palpitations, syncopes, renal insufficiency, dysphagia, gastroesophageal reflux, dyspepsia, generalized arthralgias, but also dyspareunia, or erectile dysfunction.

Early Identification of Vascular Damage in Patients With Systemic Sclerosis

Vascular involvement in systemic sclerosis (SSc) plays a key role in the pathogenesis of fibrosis. We assessed arterial stiffness using a new echo-tracking technique in patients with SSc asymptomatic for cardiovascular diseases. We enrolled 22 patients (21 female, 63 ± 14 years) and 20 controls (12 female, 62 ± 3 years). Carotid intima-media thickness (IMT) was comparable between the 2 groups (1.1 ± 0.3 vs 1.0 ± 0.4 mm, P = ns), whereas the stiffness parameters were significantly increased in patients (β: 9.5 ± 4.2 vs 5.8 ± 1.1, P = .001; pulse wave velocity [PWV]: 6.5 ± 1.5 vs 5.2 ± 0.6 m/sec, P = .003). A correlation between stiffness parameters, anti-Scl-70 antibodies (β: r = .46, P = .03; PWV: r = .50, P = .02), and anticentromere antibodies (β: r = -.54, P = .020; PWV: r = -.53, P = .023) was found. Echo-tracking technique may be valuable in early identification of vascular involvement in patients with SSc.

Pulmonary arterial hypertension associated with systemic sclerosis

Systemic sclerosis (SSc) is commonly complicated by pulmonary arterial hypertension (PAH), which is a leading cause of death in the SSc patient population. Owing to the fact that the risk of developing pulmonary hypertension is high, screening is important, although the optimal modality remains to be defined. Furthermore, despite recent advances in therapy for PAH, the response to these interventions in patients with PAH with SSc has been discouraging. The lack of clinical response to these therapies may merely reflect the limitations of traditionally employed PAH outcome measures in SSc-PAH patients or highlight the heterogeneity of the disease manifestations within SSc. Importantly, since extrapulmonary involvement of the GI tract and kidneys by SSc limit candidacy for lung transplantation, new therapies that target abnormal cellular proliferation in the pulmonary vasculature are currently under investigation and may be particularly relevant to SSc-PAH.

Comparative assessment of vascular function in autoimmune rheumatic diseases: considerations of prevention and treatment

Numerous autoimmune-inflammatory rheumatic diseases have been associated with accelerated atherosclerosis or other types of vasculopathy leading to increased cardio- and cerebrovascular disease risk. Traditional risk factors, as well as the role of systemic inflammation including cytokines, chemokines, proteases, autoantibodies, adhesion receptors and others have been implicated in the development of these vascular pathologies. The characteristics of vasculopathies may significantly differ depending on the underlying disease. While classical accelerated atherosclerosis has been associated with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) or spondyloarthropathies (SpA), obliterative vasculopathy may rather be characteristic for systemic sclerosis (SSc) or mixed connective tissue disease (MCTD). Antiphospholipid antibodies have been implicated in vasculopathies underlying SLE, antiphospholipid syndrome (APS), RA and MCTD. There is also heterogeneity with respect to inflammatory risk factors. Cytokines, such as tumor necrosis factor-α (TNF-α) or interleukin 6 (IL-6) and immune complexes are primarily involved in arthritides, such as RA, SpA, as well as in SLE. On the other hand, autoantibodies including anti-oxLDL anti-cardiolipin and anti-β2GPI are rather involved in SLE- and APS-associated vasculopathies. Regarding the non-invasive assessment of vascular function, endothelial dysfunction, overt atherosclerosis and vascular stiffness may be indicated by brachial artery flow-mediated vasodilation (FMD), common carotid intima-media thickness (ccIMT) and aortic pulse-wave velocity (PWV), respectively. These abnormalities have been described in most inflammatory rheumatic diseases. While ccIMT and stiffness are relatively stable, FMD may be influenced by many confounding factors. In addition to traditional vasculoprotection, immunosuppressive agents including corticosteroids, traditional and biologic DMARDs may have significant vascular and metabolic effects. The official EULAR recommendations on the assessment and management of cardiovascular disease in arthritides have just been published, and similar recommendations in connective tissue diseases are to be developed soon.

Vasculitis in systemic sclerosis

Systemic sclerosis (SSc) is a multiorgan connective tissue disease characterized by autoantibody production and fibroproliferative stenosis of the microvasculature. The vascoluopathy associated with SSc is considered to be noninflammatory, yet frank vasculitis can complicate SSc, posing diagnostic and therapeutic challenges. Here, we have reviewed the literature for reports of small-, medium-, and large-vessel vasculitis occurring in SSc. Amongst 88 reported cases of vasculitis in SSc, patients with ANCA-associated vasculitis appear to present a unique subclass in that they combined typical features of SSc with the renal manifestation of ANCA-associated glomerulonephritis. Other vasculitic syndromes, including large-vessel vasculitis, Behcet's disease, cryoglobulinemia, and polyarteritis nodosa, are rarely encountered in SSc patients. ANCA-associated vasculitis needs to be considered as a differential diagnosis in SSc patients presenting with renal insufficiency, as renal manifestations may result from distinct disease processes and require appropriate diagnostic testing and treatment.

Do infections facilitate the emergence of systemic sclerosis?

Systemic sclerosis (SSc) is an autoimmune disease characterized by vascular obliteration, excessive extracellular matrix deposition, and fibrosis of the connective tissues of the skin, lungs, gastrointestinal tract, heart, and kidneys. Infections are believed to play a role in the immunopathogenesis of SSc. A number of infectious agents have been proposed as possible triggering factors in SSc. Homology between viruses and autoantibody targets suggests that molecular mimicry may play a role in the initiation of antibody response in disorders characterized by diffuse vascular disease, mainly SSc. Four pathogenic hypotheses have been proposed: molecular mimicry, endothelial cell damage, super-antigens, and microchimerism. Although several studies have provided important information linking infectious agents to SSc, a clear, direct association is still missing. It is very likely that the infectious agents are cofactors in a specific hormonal and environmental setting that mounts an immune reaction, which leads to the emergence of the disorder.

The vascular microenvironment and systemic sclerosis

The role of the vascular microenvironment in the pathogenesis Systemic Sclerosis (SSc) is appreciated clinically as Raynaud's syndrome with capillary nail bed change. This manifestation of vasculopathy is used diagnostically in both limited and diffuse cutaneous subsets of SSc, and is thought to precede fibrosis. The degree of subsequent fibrosis may also be determined by the vascular microenvironment. This paper describes why the vascular microenvironment might determine the degree of end-organ damage that occurs in SSc, with a focus on vascular cell senescence, endothelial progenitor cells (EPC) including multipotential mesenchymal stem cells (MSC), pericytes, and angiogenic monocytes. An explanation of the role of EPC, pericytes, and angiogenic monocytes is important to an understanding of SSc pathogenesis. An evolving understanding of the vascular microenvironment in SSc may allow directed treatment.