IgG antiendothelial cell autoantibodies from scleroderma patients induce leukocyte adhesion to human vascular endothelial cells in vitro. Induction of adhesion molecule expression and involvement of endothelium-derived cytokines

The Interplay Between Immunity, Inflammation and Endothelial Dysfunction

The endothelium is pivotal in multiple physiological processes, such as maintaining vascular homeostasis, metabolism, platelet function, and oxidative stress. Emerging evidence in the past decade highlighted the immunomodulatory function of endothelium, serving as a link between innate, adaptive immunity and inflammation. This review examines the regulation of the immune-inflammatory axis by the endothelium, discusses physiological immune functions, and explores pathophysiological processes leading to endothelial dysfunction in various metabolic disturbances, including hyperglycemia, obesity, hypertension, and dyslipidaemia. The final section focuses on the novel, repurposed, and emerging therapeutic targets that address the immune-inflammatory axis in endothelial dysfunction.

The Phenotypes and Functions of Neutrophils in Systemic Sclerosis

Systemic sclerosis (SSc) is a chronic disease of the connective tissue characterized by its multifaceted impact on various bodily systems, yet its precise cause remains elusive. Central to its pathology are abnormal immune activation, vasculopathy, and consequent fibrosis affecting both the skin and internal organs. The intricate interplay between the innate and adaptive immune systems significantly influences the pathogenesis of SSc. Despite substantial research, the role of neutrophils, key players in innate immunity, in the context of SSc has remained enigmatic. Emerging evidence suggests that neutrophils not only contribute to the initiation and perpetuation of SSc but also inflict damage on organs and promote fibrosis-a hallmark of the disease in many patients. This review aims to investigate the nuanced involvement of neutrophils in the development of SSc. By shedding light on the intricate mechanisms through which neutrophils influence the pathogenesis of SSc, we can gain deeper insights into the disease process and potentially identify novel therapeutic targets. Understanding the precise role of neutrophils may pave the way for more targeted and effective interventions to alleviate the burden of SSc on affected individuals.

Putative functional pathogenic autoantibodies in systemic sclerosis

Systemic sclerosis (scleroderma, SSc) is a systemic disease characterized by vascular lesions, fibrosis, and circulating autoantibodies. A complex interplay between innate and adaptive immunity, and with regard to the latter, between humoral and cellular immunity, is believed to be involved in SSc pathogenesis. Lately, close attention has been paid to the role of B cells which, once activated, release profibrotic cytokines, promote profibrotic Th2 differentiation, and produce autoantibodies. Several novel interesting autoantibodies, targeting antigens within the extracellular matrix or on the cell surface, rather than the nuclear antigens of canonical SSc-autoantibodies, have been recently described in patients with SSc. As they show stimulatory or inhibitory activity or react with structures involved in the pathogenesis of SSc lesions, they can be considered as potentially pathogenic. In this paper, we will review those which have been better characterized.

Evaluation of cognitive function in systemic sclerosis patients: a pilot study

OBJECTIVE

To investigate cognitive dysfunction in adult patients with systemic sclerosis (SSc) who had no known clinical neurological manifestations and to relate it with other disease severity parameters.

METHODS

In the present study, 20 SSc consecutive female patients, who met the 2013 American College of Rheumatology SSc criteria, were compared with 20 healthy age-, gender-, and educational status-matched volunteer hospital workers. Mean age and duration of illness were 41.8 ± 12.52 and 6.9 ± 5.4 years respectively. Mini-Mental State Examination (MMSE), Wechsler Adult Intelligence scale (WAIS-III), and P300 component of event-related potentials (ERPs) were used to evaluate cognitive function in SS subjectively and objectively respectively.

RESULTS

Sixty-five percent (13 out of 20) of SSc patients had MMSE score < 25, and cognitive impairment. Despite the lack of clinically apparent neurological manifestations, SSc patients had significantly low MMSE score, high Deterioration Index (DI), and prolonged P300 latency compared with that of the control group (P = 0.0001; 0.010 and 0.008 respectively). A significant positive association was found between (DI) and the Medsger severity vascular score (r = 0.518; P = 0.012).There were few differences between limited and diffuse SSc.

CONCLUSIONS

To our knowledge, few studies highlighted that subclinical cognitive impairment can occur in the course of SSc disease. Early diagnosis of cognitive impairment should be investigated either subjectively (using psychometrics tests as MMSE or WAIS-III) or objectively using P300 evoked related potentials. Medsger severity vascular score seems to be closely related to cognitive impairment.Key points• Cognitive impairment can be associated with Medsger Vascular severity score and the duration of illness.• Further larger studies will be needed to estimate the effect of disease activity on cognitive function, to further delineate the differences between limited and diffuse SSc in this area, and to understand the underlying pathophysiological mechanisms causing cognitive impairment in patients with SSc.• To investigate impaired cognitive function in patients with SSc, even in the absence of clinically apparent neurological and vascular disease.

Key inflammatory pathways underlying vascular remodeling in pulmonary hypertension

Independent of the underlying cause, pulmonary hypertension (PH) remains a devastating condition that is characterized by limited survival. Cumulating evidence indicates that in addition to a dysbalance of mediators regulating vascular tone and growth factors promoting vascular remodeling, failure to resolve inflammation and altered immune processes play a pivotal role in the development and progression of PH. Here, we highlight the role of key inflammatory pathways in the pathobiology of vascular remodeling and PH, and discuss potential therapeutic interventions that may halt disease progression or even reverse pulmonary vascular remodeling. Perivascular inflammation is present in all forms of PH, and inflammatory pathways involve numerous mediators and cell types including macrophages, neutrophils, T cells, dendritic cells, and mast cells. Dysfunctional bone morphogenic protein receptor 2 (BMPR2) signaling and dysregulated immunity enable the accumulation of macrophages and other inflammatory cells in obliterative vascular lesions. Regulatory T cells (Tregs) were shown to be of particular relevance in the control of inflammatory responses. Key cytokines/chemokines include interleukin-6, functioning via classic or trans-signaling, macrophage migratory inhibitory factor (MIF), but also other mediators such as neutrophil-derived myeloperoxidase. The expanding knowledge on this topic has resulted in multiple opportunities for sophisticated therapeutic interventions.

Microvascular involvement in systemic sclerosis and systemic lupus erythematosus

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

[Updates in systemic sclerosis pathogenesis: Toward new therapeutic opportunities]

Systemic sclerosis is a rare connective tissue disease characterized by skin and several internal organ fibrosis, systemic vasculopathy and immune abnormalities. Even if fibroblasts and endothelial cells dysfunction, as well as lymphocytes and other immune cells implication are now well described, the exact origin and chronology of the disease pathogenesis remain unclear. Oxidative stress, influenced by genetic and environmental factors, seems to play a key role. Indeed, it seems to be implicated in the early phases of fibrosis development, vasculopathy and in immune tolerance abnormalities shared by all patients, although disease expression is heterogeneous. To date, no curative treatment is available. Even if immunosuppressive treatment or drugs acting on vascular system are proposed for some patients, overall, treatment efficiency remains modest. Only autologous hematopoietic stem cells transplantation, reserved for patients with severe or rapidly progressive fibrosis, has recently demonstrated efficiency, with lasting regression of fibrosis. Nevertheless, this treatment can expose to important, life-threatening toxicity. In the last decade, new mechanisms implicated in the pathogenesis of systemic sclerosis have been unraveled, bringing new therapeutic opportunities. In this review, we offer to focus on recent insights in the knowledge of systemic sclerosis pathogenesis and its implication in current and future medical care.

Resveratrol Mitigates High-Fat Diet-Induced Vascular Dysfunction by Activating the Akt/eNOS/NO and Sirt1/ER Pathway

We investigated whether resveratrol (RSV) can attenuate obesity and diabetes progression and improve diabetes-induced vascular dysfunction, and we attempted to delineate its underlying mechanisms. Male C57Bl/6 mice were administered a high-fat diet (HFD) for 17 weeks. Mice developed type 2 diabetes with increased body weight, hyperglycemia, hyperinsulinemia, and hyperlipidemia. Oral gavage with RSV significantly reversed the symptoms induced by the HFD. Insulin sensitivity likewise improved after the RSV intervention in these mice. Phenylephrine-induced cremaster arteriolar constriction was impaired, whereas RSV treatment significantly mitigated the vessel responsiveness to phenylephrine. The obese diabetic mice exhibited increased leukocyte rolling, adhesion, and transmigration in the postcapillary venules of the cremaster muscle. By contrast, RSV treatment significantly attenuated HFD-induced extravasation. RSV significantly recovered phosphorylated Akt and eNOS expression in the thoracic aorta. In addition, activated adenosine monophosphate-activated protein kinase in the thoracic aorta was involved in the improvement of epithelial function after RSV intervention. RSV considerably upregulated the plasma NO level in HFD mice. Moreover, RSV-enhanced human umbilical vein endothelial cells healing through Sirt1/ER pathway may be involved in the prevention of leukocyte extravasation. Collectively, RSV attenuates diabetes-induced vascular dysfunction by activating Akt/eNOS/NO and Sirt1/ER pathway. Our mechanistic study provides a potential RSV-based therapeutic strategy against cardiovascular disease.

The human glomerular endothelial cells are potent pro-inflammatory contributors in an in vitro model of lupus nephritis

Juvenile-onset lupus nephritis (LN) affects up to 80% of juvenile-onset systemic lupus erythematosus patients (JSLE). As the exact role of human renal glomerular endothelial cells (GEnCs) in LN has not been fully elucidated, the aim of this study was to investigate their involvement in LN. Conditionally immortalised human GEnCs (ciGEnCs) were treated with pro-inflammatory cytokines known to be involved in LN pathogenesis and also with LPS. Secretion and surface expression of pro-inflammatory proteins was quantified via ELISA and flow cytometry. NF-κΒ and STAT-1 activation was investigated via immunofluorescence. Serum samples from JSLE patients and from healthy controls were used to treat ciGEnCs to determine via qRT-PCR potential changes in the mRNA levels of pro-inflammatory genes. Our results identified TNF-α, IL-1β, IL-13, IFN-γ and LPS as robust in vitro stimuli of ciGEnCs. Each of them led to significantly increased production of different pro-inflammatory proteins, including; IL-6, IL-10, MCP-1, sVCAM-1, MIP-1α, IP-10, GM-CSF, M-CSF, TNF-α, IFN-γ, VCAM-1, ICAM-1, PD-L1 and ICOS-L. TNF-α and IL-1β were shown to activate NF-κB, whilst IFN-γ activated STAT-1. JSLE patient serum promoted IL-6 and IL-1β mRNA expression. In conclusion, our in vitro model provides evidence that human GEnCs play a pivotal role in LN-associated inflammatory process.

Pathophysiology of systemic sclerosis: current understanding and new insights

Introduction: Systemic sclerosis (SSc) is a complex autoimmune connective tissue disease characterized by chronic and progressive tissue and organ fibrosis with broad patient-to-patient variability. Some risk factors are known and include combination of persistent Raynaud's phenomenon, steroid hormone imbalance, selected chemicals, thermal, or other injuries. Endogenous and/or exogenous environmental trigger/risk factors promote epigenetic mechanisms in genetically primed subjects. Disease pathogenesis presents early microvascular changes with endothelial cell dysfunction, followed by the activation of mechanisms promoting their transition into myofibroblasts. A complex autoimmune response, involving innate and adaptive immunity with specific/functional autoantibody production, characterizes the disease. Progressive fibrosis and ischemia involve skin and visceral organs resulting in their irreversible damage/failure. Progenitor circulating cells (monocytes, fibrocytes), together with growth factors and cytokines participate in disease diffusion and evolution. Epigenetic, vascular and immunologic mechanisms implicated in systemic fibrosis, represent major targets for incoming disease modifying therapeutic approaches. Areas covered: This review discusses current understanding and new insights of SSc pathogenesis, through an overview of the most relevant advancements to present aspects and mechanisms involved in disease pathogenesis. Expert opinion: Considering SSc intricacy/heterogeneity, early combination therapy with vasodilators, immunosuppressive and antifibrotic drugs should successfully downregulate the disease progression, especially if started from the beginning.

Neurosonological and cognitive screening for evaluation of systemic sclerosis patients

OBJECTIVE

Assessment of cerebrovascular hemodynamics, third ventricle diameter (as a proxy of brain atrophy) by transcranial sonography (TCS), and screening of cognitive performance by the Symbol Digit Modalities Test (SDMT) in systemic sclerosis (SSc) patients.

METHODS

A total of 38 SSc patients recruited from the outpatient clinic of the Rheumatology Department, Kasr Alainy Hospital, Cairo University, and 51, age- and sex-matched, healthy controls were included in the study. TCS was used to assess the mean flow velocity (MFV), pulsatility index (PI) of the anterior, middle, and posterior cerebral arteries bilaterally, and to measure the third ventricle diameter as a proxy of brain atrophy. Cognitive impairment was screened using the SDMT. p values < 0.05 were considered statistically significant.

RESULTS

There was no significant difference between SSc patients and controls regarding either PI or MFV of the anterior, middle, and posterior cerebral arteries; also, there was no difference regarding the third ventricle diameter; however, limited SSc patients showed a significant increase in the PI of PCA and MFV of ACA as compared with diffuse SSc patients (p = 0.005, 0.004). There was a significant difference between SSc patients and controls regarding the SDMT (p = 0.016).

CONCLUSION

There is an evidence of increased cerebral vascular tone and resistance in limited SSc patients compared with diffuse SSc subgroup, without evidence of cerebral atrophy, suggesting early cerebrovascular affection even in asymptomatic limited SSc patients. There was also an evidence of cognitive impairment in SSc patients.

Thrombin Contributes to Anti-myeloperoxidase Antibody Positive IgG-Mediated Glomerular Endothelial Cells Activation Through SphK1-S1P-S1PR3 Signaling

Background: Activation of coagulation system plays an important role in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) pathogenesis. Thrombin, generated during coagulation could disrupt endothelial barrier integrity through protease-activated receptor 1 (PAR1). Our previous study found that sphingosine-1-phosphate (S1P) contributed to myeloperoxidase (MPO)-ANCA-positive IgG-induced glomerular endothelial cell (GEnC) activation through a S1P receptor (S1PR)-dependent route. In recent years, S1P signaling was reported to be involved in thrombin effects on endothelial cells. This current study investigated whether the interaction between thrombin-PAR and S1P-S1PR signaling contributed to MPO-ANCA-positive IgG-induced GEnC dysfunction.

Methods: The effect of thrombin on GEnC activation was analyzed from three aspects. First, morphological alteration of GEnCs was observed. Second, permeability assay was performed to determine GEnC monolayer activation quantitatively. Third, endothelin-1 (ET-1) levels were measured. Expression levels of sphingosine kinases (SphKs) and S1PRs were detected. In addition, antagonists of PAR1 and S1PR3 were employed to determine their roles. Eventually, PAR1 and tissue factor (TF) expression levels as well as TF procoagulant activity were analyzed.

Results: Thrombin induced further damage of tight junction, increase in endothelial monolayer permeability as well as upregulation of ET-1 levels in GEnCs stimulated with MPO-ANCA-positive IgG. Blocking PAR1 downregulated ET-1 levels in the supernatants of GEnCs treated by thrombin plus MPO-ANCA-positive IgG. Expression levels of SphK1, S1PR3 increased significantly in GEnCs treated with thrombin plus MPO-ANCA-positive IgG. S1P upregulated PAR1 and TF expression, and enhanced procoagulant activity of TF in MPO-ANCA-positive IgG-stimulated GEnCs.

Conclusion: Thrombin synergized with SphK1-S1P-S1PR3 signaling pathway to enhance MPO-ANCA-positive IgG-mediated GEnC activation.

Anti-carbamylated protein antibodies and skin involvement in patients with systemic sclerosis: An intriguing association

Carbamylation is a post-translational modification that mostly affects proteins with low turnover, such as dermal proteins. Carbamylated proteins accumulate in skin in an age-dependent manner, contributing to tissue alterations. As dermis is affected by systemic sclerosis (SSc) and anti-carbamylated protein antibodies (anti-CarP Ab) are found in SSc patients, we sought to evaluate the specificity of anti-CarP Ab and their relationship with clinical parameters reflecting skin involvement in SSc. This study investigated serum samples and clinical data from 124 patients with SSc. Anti-CarP Ab were affinity purified from pooled SSc sera, and their specificity was assessed by western blotting and ELISA with carbamylated proteins from two species (human and bovine albumin; human fibrinogen). Anti-CarP Ab were measured in SSc serum samples and in 41 healthy aged-matched individuals. Affinity-purified anti-CarP Ab recognized carbamylated epitopes irrespective of the protein type or species origin. Anti-CarP Ab levels inversely correlated with the modified Rodnan skin score (mRss) (Spearman's R = -0.32, p<0.001), independently of patients' age. Receiver operating characteristics (ROC) analysis identified anti-CarP Ab cut-offs that best discriminated dichotomized clinical variables related to skin involvement: the only clinical variables that were significantly different between groups were mRss (p = 0.001) and scleredema (p<0.001). Low anti-CarP Ab levels were associated with worse skin involvement. Future prospective studies are needed to assess their usefulness in the clinical setting.

Implications of endothelial shear stress on systemic sclerosis vasculopathy and treatment

There are no Federal Drug Administration approved drugs for the treatment of systemic sclerosis vascular digital ulcers (DU) in the United States, which are thought to be an end-stage result of prolonged ischaemia due to severe, prolonged Raynaud's phenomenon. Most therapeutics for vasodilation used in SSc work different pathways to target the smooth muscle to induce vessel relaxation. Longitudinal studies of vascular function allow insight into the effects of medications used for Raynaud's phenomenon in the SSc patient population. In this review, we discuss vascular tone, the function of the endothelium in SSc, and provide the rationale for longitudinal studies of vascular function and therapeutics that target the endothelial shear stress in addition to vasodilation for treatment and prevention of DU. This review provides the rationale for vasodilatory medication use for treatment of SSc-related DU and justifies access to non-FDA approved medications for this indication.

Sphingosine-1-phosphate (S1P) enhances glomerular endothelial cells activation mediated by anti-myeloperoxidase antibody-positive IgG

Cumulating evidences suggested an important role of sphingosine-1-phosphate (S1P) and its receptors in regulating endothelial barrier integrity. Our previous study revealed that the circulating S1P levels and renal expression of S1PRs correlated with disease activity and renal damage in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). This study investigated the role of S1P and its receptors in myeloperoxidase (MPO)-ANCA-positive IgG-mediated glomerular endothelial cell (GEnC) activation. The effect of S1P on morphological alteration of GEnCs in the presence of MPO-ANCA-positive IgG was observed. Permeability assay was performed to determine endothelial monolayer activation in quantity. Both membrane-bound and soluble ICAM-1 and VCAM-1 levels were measured. Furthermore, antagonists and/or agonists of various S1PRs were employed to determine the role of different S1PRs. S1P enhanced MPO-ANCA-positive IgG-induced disruption of tight junction and disorganization of cytoskeleton in GEnCs. S1P induced further increase in monolayer permeability of GEnC monolayers in the presence of MPO-ANCA-positive IgG. S1P enhanced MPO-ANCA-positive IgG-induced membrane-bound and soluble ICAM-1/VCAM-1 up-regulation of GEnCs. Soluble ICAM-1 levels in the supernatants of GEnCs stimulated by S1P and MPO-ANCA-positive IgG increased upon pre-incubation of S1PR1 antagonist, while pre-incubation of GEnCs with the S1PR1 agonist down-regulated sICAM-1 level. Blocking S1PR2-4 reduced sICAM-1 levels in the supernatants of GEnCs stimulated by S1P and MPO-ANCA-positive IgG. Pre-incubation with S1PR5 agonist could increase sICAM-1 level in the supernatants of GEnC stimulated by S1P and MPO-ANCA-positive IgG. S1P can enhance MPO-ANCA-positive IgG-mediated GEnC activation through S1PR2-5.

Functional autoantibodies directed against cell surface receptors in systemic sclerosis

Systemic sclerosis (SSc) is a complex and heterogeneous systemic autoimmune disease characterized by the presence of high serum levels of antibodies targeting a variety of self-antigens. In addition to autoantibodies directed against nuclear antigens, patients with SSc also develop high serum levels of functional autoantibodies that target cell surface receptors when compared to healthy subjects. Following binding to extracellular receptors, these functional autoantibodies trigger the activation of signal transducing pathways, resulting in a stimulatory or suppressive effect. For example, stimulatory autoantibodies toward platelet-derived growth factor receptor (PDGFR) or antibodies targeting G protein–coupled receptors (e.g., angiotensin II receptor type 1 and endothelin receptor type A) have pleiotropic roles in the pathogenesis of SSc. High levels of these functional autoantibodies dysregulate the response of non-immune cells (e.g., fibroblasts and endothelial cells) as well as innate and adaptive immune cells, including myeloid cells and lymphocytes, respectively. Thus, the immunobiology of such autoantibodies clarifies why patients with SSc develop clinical features such as extensive fibrosis, vasculopathies and abnormal immune responses. Future interventions that modulate the natural production of functional autoantibodies that target cell surface receptors or neutralize such autoantibodies would be essential in reducing morbidity and mortality rates presented by SSc patients.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Soluble vascular endothelial (VE) cadherin and autoantibodies to VE-cadherin in rheumatoid arthritis patients treated with etanercept or adalimumab

OBJECTIVES

The aim of this study was to investigate the clinical value of sVE and anti-vascular endothelial-cadherin antibodies (AAVE) in RA treated with etanercept or adalimumab combined with methotrexate.

METHODS

This was an 18-month prospective multicenter study in which patients had active RA, requiring TNF antagonist. sVE rates and AAVE titers were measured respectively by dot blot and ELISA. The relationship of these biomarkers with parameters reflecting articular or systemic disease activity, progression of structural damage, and response or remission to treatment was analyzed.

RESULTS

Forty-eight patients received TNF blocking agents. Variation of sVE rates were significantly correlated with that of C-reactive protein (CRP) levels at weeks 6, 12, 26 and 52. A significant decrease in sVE levels was observed in the group of patients exhibiting a decrease in CRP levels as compared to the patient group with unmodified CRP. AAVE at baseline were correlated with rheumatoid factor. Kinetics analysis of sVE levels and AAVE titers showed that their level were not associated with disease activity score and to methotrexate/adalimumab or etanercept response.

CONCLUSIONS

sVE is a biomarker associated with systemic RA activity under anti-TNF. AAVE are related to autoantibodies usually associated to RA.

Current perspectives on the immunopathogenesis of systemic sclerosis

Systemic sclerosis (SSc or scleroderma) is a progressive and highly debilitating autoimmune disorder characterized by inflammation, vasculopathy, and extensive fibrosis. SSc is highly heterogeneous in its clinical presentation, extent and severity of skin and internal organ involvement, and clinical course and has the highest fatality rate among connective tissue diseases. While clinical outcomes have improved in recent years, no current therapy is able to reverse or slow the natural progression of SSc, a reflection of its complex pathogenesis. Although activation of the immune system has long been recognized, the mechanisms responsible for the initiation of autoimmunity and the role of immune effector pathways in the pathogenesis of SSc remain incompletely understood. This review summarizes recent progress in disease pathogenesis with particular focus on the immunopathogenetic mechanisms of SSc.

Cytokines in the immunopathology of systemic sclerosis

Cytokines and growth factors are key regulators of immune activation, vascular alteration and excessive production of extracellular matrix which are hallmark events in the pathogenesis of systemic sclerosis (SSc). They modulate cell-cell and cell-matrix interactions. In particular, cytokines play a central role in the immunopathogenesis of SSc on the basis of molecular pathways which are complex and not completely understood. The majority of cytokines that may be involved in SSc pathogenesis have effect upon or are derived from cells of the immune system, including both the innate and adaptive compartments. Novel therapies that block key mediators that drive the fibrotic response are being developed and appear as potential therapeutic tools in the treatment of SSc, highlighting the importance for an effective therapy targeted towards the molecular and cellular pathways. This article reviews cytokine biology in that context, with particular emphasis on immunopathology of the disease, therapeutic targeting and the way that current or emerging treatments for SSc might impact on cytokine biology.

The Pathogenesis of Systemic Sclerosis

Systemic sclerosis is a multisystem disorder with a high associated mortality. The hallmark abnormalities of the disease are in the immune system, vasculature, and connective tissue. Systemic sclerosis occurs in susceptible individuals and is stimulated by initiating events that are poorly understood at present. In order for the disease phenotype to appear there is dysfunction in the homoeostatic mechanisms of immune tolerance, endothelial physiology, and extracellular matrix turnover. The progression of disease is not sequential but requires simultaneous dysfunction in these normal regulatory mechanisms. Better understanding of the interplay of these factors is likely to contribute to improved treatment options.

Post-infectious group A streptococcal autoimmune syndromes and the heart

There is a pressing need to reduce the high global disease burden of rheumatic heart disease (RHD) and its harbinger, acute rheumatic fever (ARF). ARF is a classical example of an autoimmune syndrome and is of particular immunological interest because it follows a known antecedent infection with group A streptococcus (GAS). However, the poorly understood immunopathology of these post-infectious diseases means that, compared to much progress in other immune-mediated diseases, we still lack useful biomarkers, new therapies or an effective vaccine in ARF and RHD. Here, we summarise recent literature on the complex interaction between GAS and the human host that culminates in ARF and the subsequent development of RHD. We contrast ARF with other post-infectious streptococcal immune syndromes - post-streptococcal glomerulonephritis (PSGN) and the still controversial paediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS), in order to highlight the potential significance of variations in the host immune response to GAS. We discuss a model for the pathogenesis of ARF and RHD in terms of current immunological concepts and the potential for application of in depth "omics" technologies to these ancient scourges.

Proteomic identification of heterogeneous nuclear ribonucleoprotein K as a novel cold-associated autoantigen in patients with secondary Raynaud's phenomenon

OBJECTIVE

The aim of this study was to identify cold-associated autoantibodies in patients with RP secondary to CTDs.

METHODS

Indirect immunofluorescence staining was performed on non-permeabilized cold-stimulated normal human dermal microvascular endothelial cells (dHMVECs), using patients' sera. Cold-induced alterations in cell surface proteomes were analysed by isobaric tag for relative and absolute quantitation (iTRAQ) analysis. Serological proteome analysis (SERPA) was applied to screen cold-associated autoantigens. The prevalence of the candidate autoantibody was determined by ELISA in 290 patients with RP secondary to CTDs (SSc, SLE or MCTD), 10 patients with primary RP and 27 healthy controls.

RESULTS

Enhanced cell surface immunoreactivity was detected in cold-stimulated dHMVECs when incubated with sera from patients with secondary RP. By iTRAQ analysis, many proteins, including heterogeneous nuclear ribonucleoprotein K (hnRNP-K), were found to be increased on the cell surface of dHMVECs after cold stimulation. By the SERPA approach, hnRNP-K was identified as a candidate autoantigen in patients with secondary RP. Cold-induced translocation of hnRNP-K to the cell surface was confirmed by immunoblotting and flow cytometry. By ELISA analysis, patients with secondary RP show a significantly higher prevalence of anti-hnRNP-K autoantibody (30.0%, 61/203) than patients without RP (9.2%, 8/87, P = 0.0001), patients with primary RP (0%, 0/10, P = 0.0314) or healthy controls (0%, 0/27, P = 0.0001).

CONCLUSION

By comprehensive proteomics, we identified hnRNP-K as a novel cold-associated autoantigen in patients with secondary RP. Anti-hnRNP-K autoantibody may potentially serve as a biomarker for RP secondary to various CTDs.

Inflammation and immunity in the pathogenesis of pulmonary arterial hypertension

This review summarizes an expanding body of knowledge indicating that failure to resolve inflammation and altered immune processes underlie the development of pulmonary arterial hypertension. The chemokines and cytokines implicated in pulmonary arterial hypertension that could form a biomarker platform are discussed. Pre-clinical studies that provide the basis for dysregulated immunity in animal models of the disease are reviewed. In addition, we present therapies that target inflammatory/immune mechanisms that are currently enrolling patients, and discuss others in development. We show how genetic and metabolic abnormalities are inextricably linked to dysregulated immunity and adverse remodeling in the pulmonary arteries.

Anti-endothelial cell antibodies in connective tissue diseases associated with pulmonary arterial hypertension

OBJECTIVE

To investigate the prevalence of anti-endothelial cell antibodies (AECA) in connective tissue diseases (CTD) associated with pulmonary arterial hypertension (PAH) and to corroborate the pathologic function of AECA in PAH-associated CTDs.

METHODS

AECA were detected by cellular enzyme-linked immunosorbent assay (ELISA) in sera of 19 PAH-associated CTD patients, 22 CTD patients without PAH involvement, and 20 age- and sex-matched healthy individuals as controls. Using IgG purified from the sera of AECA-positive, AECA-negative, and healthy subjects, the effects of AECA on the expression of ICAM-1 and the chemokine regulated upon activation normal T-cell expressed and secreted (RANTES) in cultured endothelial cells were also evaluated.

RESULTS

A total of 12 of the 19 (63.2%) CTD patients with PAH, 9 of the 22 (40.9%) CTD patients without PAH, and 1 of the 20 (5%) healthy controls were positive for AECA, which were calculated as ELISA ratio (ER) values. ER values in PAH-associated CTD patients were significantly higher than those with CTD without PAH (3.68±2.05 versus 1.67±1.07, P<0.001). IgG purified from AECA-positive sera induced a significantly increased level of ICAM-1 expression after 48 h incubation (795.2±32.5 pg/mL) compared with AECA-negative or healthy control IgG (231.5±27.1 and 192.8±33.4 pg/mL, respectively; P<0.001). In addition, RANTES production by cultured human pulmonary arterial endothelial cells (HPAECs) increased in both a time- and concentration-dependent manner in response to incubation with purified AECA-positive IgG.

CONCLUSIONS

AECA could be involved in CTD and might participate in the pathogenesis of PAH-associated CTD.

[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.

The role of inflammation and autoimmunity in the pathophysiology of pulmonary arterial hypertension

Pulmonary arterial hypertension is characterized by a remodeling of pulmonary arteries with endothelial cell, fibroblast, and vascular smooth muscle cell activation and proliferation. Since pulmonary arterial hypertension occurs frequently in autoimmune conditions such as systemic sclerosis, inflammation and autoimmunity have been suspected to play a critical role in both idiopathic pulmonary arterial hypertension and systemic sclerosis-associated pulmonary arterial hypertension. High levels of pro-inflammatory cytokines such as interleukin-1 and interleukin-6, platelet-derived growth factor, or macrophage inflammatory protein 1 have been found in lung samples of patients with pulmonary arterial hypertension, along with inflammatory cell infiltrates mainly composed of macrophages and dendritic cells, T and B lymphocytes. In addition, circulating autoantibodies are found in the peripheral blood of patients. Thus, autoimmunity and inflammation probably play a role in the development of pulmonary arterial hypertension. In this setting, it would be important to set-up new experimental models of pulmonary arterial hypertension, in order to define novel therapeutics that specifically target immune disturbances in this devastating condition.

Agonistic anti-ICAM-1 antibodies in scleroderma: activation of endothelial pro-inflammatory cascades

Background

Scleroderma (SSc) is a complex autoimmune disorder that can be characterised by the presence 2of circulating autoantibodies to nuclear, cytoplasmic and cell surface antigens. In particular antibodies directed against endothelial cell antigens (anti-endothelial cell antibodies; AECA) have been detected.

ICAM-1 is an adhesion molecule expressed on the surface of human endothelial cells. We have previously shown that cross-linking ICAM-1 with monoclonal antibodies leads to pro-inflammatory activation of human endothelial and vascular smooth muscle cells and that cardiac transplant recipients with transplant associated vasculopathy make antibodies directed against ICAM-1.

Objectives

To determine whether SSc patients make antibodies directed against ICAM-1 and whether these antibodies induce pro-inflammatory activation of human endothelial cells in vitro.

Methods

Using recombinant ICAM-1 as capture antigen, an ELISA was developed to measure ICAM-1 antibodies in sera from SSc patients. Antibodies were purified using ICAM-1 micro-affinity columns. HUVEC were incubated with purified anti-ICAM-1 antibodies and generation of reactive oxygen species, and expression of VCAM-1 was measured.

Results

Significantly elevated levels of anti-ICAM-1 antibodies were detected in patients with diffuse (dSSc; 10/31 32%) or limited (lSSc; 14/36 39%) scleroderma. Cross-linking of HUVEC with purified anti-ICAM-1 antibodies caused a significant increase in ROS production (2.471 ± 0.408 fold increase above untreated after 150 min p < 0.001), and significant increase in VCAM-1 expression (10.6 ± 1.77% vs 4.12 ± 1.33%, p < 0.01).

Conclusion

AECA from SSc patients target specific endothelial antigens including ICAM-1, and cause pro-inflammatory activation of human endothelial cells, suggesting that they are not only a marker of disease but that they contribute to its progression.

Anticipated classes of new medications and molecular targets for pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) remains a life-limiting condition with a major impact on the ability to lead a normal life. Although existing therapies may improve the outlook in some patients there remains a major unmet need to develop more effective therapies in this condition. There have been significant advances in our understanding of the genetic, cell and molecular basis of PAH over the last few years. This research has identified important new targets that could be explored as potential therapies for PAH. In this review we discuss whether further exploitation of vasoactive agents could bring additional benefits over existing approaches. Approaches to enhance smooth muscle cell apotosis and the potential of receptor tyrosine kinase inhibition are summarised. We evaluate the role of inflammation, epigenetic changes and altered glycolytic metabolism as potential targets for therapy, and whether inherited genetic mutations in PAH have revealed druggable targets. The potential of cell based therapies and gene therapy are also discussed. Potential candidate pathways that could be explored in the context of experimental medicine are identified.

[Critical limb ischemia in systemic sclerosis]

Vascular complications are common in systemic sclerosis (SSc). Critical limb ischemia leading to gangrene or amputation occurs in more than 10% of these patients and hence is a common emergency. This report highlights the different pathogenetic mechanisms leading to critical ischemic events and provides guidance for the diagnosis and therapy. Apart from SSc-associated vasculopathy and peripheral arterial disease, thromboembolic events and rarely also vasculitis may cause critical limb ischemia. An interdisciplinary approach to the diagnosis and therapy of these lesions is mandatory. Therapy goals are the prevention of further ischemia and, if possible, revascularization as well as optimal pain management.

Inflammation in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is characterized by pulmonary vascular remodeling of the precapillary pulmonary arteries, with excessive proliferation of vascular cells. Although the exact pathophysiology remains unknown, there is increasing evidence to suggest an important role for inflammation. Firstly, pathologic specimens from patients with PAH reveal an accumulation of perivascular inflammatory cells, including macrophages, dendritic cells, T and B lymphocytes, and mast cells. Secondly, circulating levels of certain cytokines and chemokines are elevated, and these may correlate with a worse clinical outcome. Thirdly, certain inflammatory conditions such as connective tissue diseases are associated with an increased incidence of PAH. Finally, treatment of the underlying inflammatory condition may alleviate the associated PAH. Underlying pathologic mechanisms are likely to be "multihit" and complex. For instance, the inflammatory response may be regulated by bone morphogenetic protein receptor type 2 (BMPR II) status, and, in turn, BMPR II expression can be altered by certain cytokines. Although antiinflammatory therapies have been effective in certain connective-tissue-disease-associated PAH, this approach is untested in idiopathic PAH (iPAH). The potential benefit of antiinflammatory therapies in iPAH is of importance and requires further study.

ANCA-associated vasculitis in systemic sclerosis report of 3 cases

The aim of the study was to describe the occurrence of anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) in systemic sclerosis (SSc) patients. SSc patients who developed biopsy-proven AAV were identified. Their clinical manifestations, autoantibodies, presentation with vasculitis, treatment and outcome were described and compared with previously reported patients with these two conditions. Of 985 patients, 3 were identified. All patients had interstitial lung disease, and all presented with acute renal failure, proteinuria and hematuria, and were P-ANCA- and anti-Scl-70-positive. One required hemodialysis. Two were hypertensive; additionally, one patient had sinusitis, and another had monoarthritis and a macular rash. All were treated with high-dose corticosteroids and responded to therapy and attained remission at 6 months. At 1 year, one patient died of pneumonia. ANCA-associated vasculitis is a rare but serious finding in SSc patients. Positive anti-Scl-70 antibody is found commonly in these patients. Different treatment modalities are effective. Serious infections can complicate therapy and lead to death.

Animal models of cutaneous and hepatic fibrosis

Fibrosis occurs as a part of normal wound healing. However, excessive or dysregulated fibrosis can lead to severe organ dysfunction and is a feature of a variety of diseases. Due to its insidious onset, fibrosis tends to go undetected in its early stages. This is in part why these diseases remain so poorly understood. Animal models have provided a means to examine these early stages and to isolate and understand the effect of perturbations in signaling pathways, chemokines, and cytokines. Here, we summarize recent progress in the understanding of the molecular pathogenesis of fibrosis, both its initiation and its maintenance phases, from animal models of fibrosis in the skin and liver. Due to these organs' properties, modeling fibrosis in them poses unique challenges. Elegant solutions have therefore been developed for modeling fibrosis in each, and now, great potential for animal models to contribute to our understanding appears scientifically imminent.

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.

HMC05, Herbal Formula, Inhibits TNF-α-Induced Inflammatory Response in Human Umbilical Vein Endothelial Cells

Vascular inflammation has been implicated in the progression of cardiovascular diseases such as atherosclerosis. In the present study, we found that HMC05, an extract from eight different herbal mixtures, dose-dependently inhibited tumor necrosis factor-α (TNF-α)-induced adhesion of monocytes to endothelial cells. Such inhibitory effect of HMC05 correlated with suppressed expression of monocyte chemoattractant protein-1, CC chemokine receptor 2, vascular cell adhesion molecule-1 and intercellular cell adhesion molecule-1. In addition, HMC05 significantly inhibited production of reactive oxygen species (ROS) and nuclear factor (NF)-κB activation by TNF-α. Those inhibitory effects of HMC05 (1–10 μg mL⁻¹) on the TNF-α-induced inflammatory event was similar to those of berberine (1–10 μM), which is a major component of HMC05 and one of herbal compounds known to have vasorelaxing and lipid-lowering activities. However, berberine significantly reduced the viability of HUVECs in a time- and concentration-dependent manner. In contrast, HMC05 (1–10 μg ml⁻¹) did not affect the cell viability for up to 48 h treatment. In conclusion, we propose that HMC05 may be a safe and potent herbal formula against vascular inflammation, and its action may be attributable to the inhibition of ROS- and NF-κB-dependent expression of adhesion molecules and chemokines.

Thrombospondin 1 in hypoxia-conditioned media blocks the growth of human microvascular endothelial cells and is increased in systemic sclerosis tissues

Background

Systemic sclerosis (SSc) is a chronic inflammatory autoimmune disease characterised by vascular dysfunction and damage, excess collagen deposition and subsequent organ manifestations. Vasculopathy is an early feature of the disease which leads to a chronic hypoxic environment in the tissues. Paradoxically, there is a lack of angiogenesis. We hypothesised that this may in part be due to a nonphysiological, overriding upregulation in antiangiogenic factors produced by the hypoxic tissues. We considered thrombospondin 1 (TSP-1) as a candidate antiangiogenic factor.

Results

Conditioned media from human microvascular endothelial cells cultured in both normoxic and hypoxic environments were able to block endothelial cell proliferation, with the latter environment having a more profound effect. Filtration to remove > 100-kDa proteins or heparin-binding proteins from the conditioned media eliminated their antiproliferative effect. TSP-1 was expressed in high concentrations in the hypoxic media, as was vascular endothelial growth factor (VEGF). Depletion of TSP-1 from the media by immunoprecipitation reduced the antiproliferative effect. We then show that, in a dose-dependent fashion, recombinant TSP-1 blocks the proliferation of endothelial cells. Immunohistochemistry of skin biopsy material revealed that TSP-1 expression was significantly higher throughout the skin of patients with SSc compared with healthy controls.

Conclusions

Despite the environment of chronic tissue hypoxia in SSc, there is a paradoxical absence of angiogenesis. This is thought to be due in part to aberrant expression of antiangiogenic factors, including TSP-1. We have demonstrated that TSP-1 is released in high concentrations by hypoxic endothelial cells. The conditioned media from these cells is able to block proliferation and induce apoptosis in microvascular endothelial cells, an effect that is reduced when TSP-1 is immunoprecipitated out. Further, we have shown that recombinant TSP-1 is able to block proliferation and induce apoptosis at concentrations consistent with those found in the plasma of patients with SSc and that its effect occurs in the presence of elevated VEGF levels. Taken together, these data are consistent with a model wherein injured microvascular cells in SSc fail to repair because of dysregulated induction of TSP-1 in the hypoxic tissues.

Anti-endothelial cell antibodies in rheumatic heart disease

To evaluate the anti-endothelial cell antibodies (AECA), anti-cardiolipin antibodies (aCL) and serum mannose-binding lectin (MBL) profiles of a large cohort of Yemeni patients with rheumatic heart disease (RHD) and to correlate these findings with clinical features of the disease. Patients (n = 140) were recruited from Al-Thawra Hospital in Sana'a, Yemen. All had RHD diagnosed according to modified Jones' criteria. We also studied 140 sex- and age-matched healthy blood donors from the same area. Echocardiography was performed according to the recommendations of the American Society of Echocardiography. Solid phase enzyme-linked immunosorbent assays (ELISAs) were used to measure AECA and aCL titres and serum MBL levels. Forty per cent of the patients were AECA-positive, but only 7·8% were positive for aCL antibodies. Serum MBL levels were significantly lower in the RHD group (median 4221 ng/ml versus 5166 ng/ml in healthy controls). AECA titres were correlated positively with patient age, duration of RHD and the severity of aortic stenosis, as determined by echocardiographic findings. In several autoimmune rheumatic diseases, such as systemic lupus erythematosus, vasculitis and scleroderma, AECA have been shown to play pathogenic roles by producing proinflammatory and procoagulant effects (increased expression of adhesion molecules and tissue factors, increased cytokine release) in endothelial cells. In RHD, these autoantibodies might represent a pathological link between activation of the valvular endothelium and valvular damage.

Molecular mimicry of human endothelial cell antigen by autoantibodies to nonstructural protein 1 of dengue virus

The pathogenesis of dengue hemorrhagic fever and dengue shock syndrome (DHF/DSS), both serious complications of dengue virus (DV) infection, remains unclear. In this study, we found that anti-DV NS1 (nonstructural protein 1) polyclonal antibodies cross-reacted with human umbilical vein endothelial cells (HUVECs). We further identified a complex-specific mAb, DB16-1, which could recognize DV NS1 and cross-react with HUVECs and human blood vessels. The target protein of DB16-1 was further purified by immunoaffinity chromatography. LC-MS/MS analysis and co-immunoprecipitation revealed that the target protein of DB16-1 was human LYRIC (lysine-rich CEACAM1 co-isolated). Our newly generated anti-LYRIC mAbs bound to HUVECs in a pattern similar to that of DB16-1. The B-cell epitope of DB16-1 displayed a consensus motif, Lys-X-Trp-Gly (KXWG), which corresponded to amino acid residues 116-119 of DV NS1 and mimicked amino acid residues 334-337 in LYRIC. Moreover, the binding activity of DB16-1 in NS1 of DV-2 and in LYRIC disappeared after the KXWG epitope was deleted in each. In conclusion, DB16-1 targeted the same epitope in DV NS1 and LYRIC protein on human endothelial cells, suggesting that it might play a role in the pathogenesis of DHF/DSS. Future studies on the role of the anti-NS1 antibody in causing vascular permeability will undoubtedly be performed on sera collected from individuals before, during, and after the endothelial cell malfunction phase of a dengue illness.

Digital ischemia in scleroderma spectrum of diseases

Systemic Sclerosis (Scleroderma, SSc) is a disease of unknown etiology characterized by widespread vasculopathy and extracellular matrix deposition leading to fibrosis and autoimmune processes. Digital ischemia (digital ulcers (DUs)) is the hallmark of SSc-related vasculopathy and is characterized by endothelial dysfunction leading to intimal proliferation and thrombosis. It happens frequently (30% of the patients each year) and it is associated with significant morbidity. This paper summarizes the current information regarding pathogenesis, definitions, management, and exploratory therapies in DUs associated with SSc.

Antiendothelial cell antibodies induce apoptosis of bone marrow endothelial progenitors in systemic sclerosis

OBJECTIVE

Patients with systemic sclerosis (SSc) have significantly fewer and functionally impaired endothelial progenitor cells (EPC) in peripheral blood and bone marrow; further, endothelial apoptosis seems to play a primary role in the pathogenesis of vascular damage. We investigated whether the failure of bone marrow EPC is related to their apoptotic phenotype and analyzed the possible mechanisms inducing apoptosis.

METHODS

The presence of apoptotic cells was investigated in bone marrow aspirates taken from patients with SSc; microvessel density (MVD) and the immunohistochemical expression of vascular endothelial growth factor (VEGF) were also measured in bone marrow biopsies. A correlation between EPC apoptosis and the presence of antiendothelial cell antibodies (AECA) was also investigated.

RESULTS

We confirmed the presence of bone marrow EPC dysfunction in SSc, while hematopoiesis was not impaired. Bone marrow studies showed a high percentage of apoptotic progenitors, no signs of fibrosis or an altered MVD, and an increased VEGF index. The patients' bone marrow plasma showed significant titers of AECA, and their presence correlated with that of apoptotic progenitors. These findings were further confirmed by an in vitro assay in which the apoptosis of normal progenitors was induced by the addition of AECA+ purified IgG.

CONCLUSION

Our results showed that apoptosis in patients with SSc involves the source compartment of endothelial progenitors and correlates with AECA activity. These findings support the hypothesis that AECA may play a pathogenetic role by affecting the bone marrow EPC machinery that should repair the peripheral vascular lesions.

A clinical cardiology perspective of thrombophilias

Thrombophilias, an inherited and/or acquired predisposition to vascular thrombosis beyond hemostatic needs are common in cardiovascular medicine and include systemic disorders such as coronary atherosclerosis, atrial fibrillation, exogenous obesity, metabolic syndrome, collagen vascular disease, human immunodeficiency virus, blood replacement therapy and several commonly used medications. A contemporary approach to patients with suspected thrombophilias, in addition to a very selective investigation for gain-of-function and loss-of-function gene mutations affecting thromboresistance, must consider prevalent diseases and management decisions encountered regularly by cardiologists in clinical practice. An appropriate recognition of common disease states as thrombophilias will also stimulate platforms for much needed scientific investigation.