Nifedipine decreases sVCAM-1 concentrations and oxidative stress in systemic sclerosis but does not affect the concentrations of vascular endothelial growth factor or its soluble receptor 1

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

Introduction

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

Methods

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

Results

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

Discussion

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

Systematic review registration

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

Association of Circulating Vascular Endothelial Growth Factor Levels With Autoimmune Diseases: A Systematic Review and Meta-Analysis

Background

Autoimmune diseases (ADs) are characterized by immune-mediated tissue damage, in which angiogenesis is a prominent pathogenic mechanism. Vascular endothelial growth factor (VEGF), an angiogenesis modulator, is significantly elevated in several ADs including rheumatoid arthritis (RA), systemic sclerosis (SSc), and systemic lupus erythematosus (SLE). We determined whether circulating VEGF levels were associated with ADs based on pooled evidence.

Methods

The analyses included 165 studies from the PubMed, EMBASE, Cochrane Library, and Web of Science databases and fulfilled the study criteria. Comparisons of circulating VEGF levels between patients with ADs and healthy controls were performed by determining pooled standard mean differences (SMDs) with 95% confidence intervals (CIs) in a random-effect model using STATA 16.0. Subgroup, sensitivity, and meta-regression analyses were performed to determine heterogeneity and to test robustness.

Results

Compared with healthy subjects, circulating VEGF levels were significantly higher in patients with SLE (SMD 0.84, 95% CI 0.25-1.44, P = 0.0056), RA (SMD 1.48, 95% CI 0.82-2.15, P <0.0001), SSc (SMD 0.56, 95% CI 0.36-0.75, P <0.0001), Behcet's disease (SMD 1.65, 95% CI 0.88-2.41, P <0.0001), Kawasaki disease (SMD 2.41, 95% CI 0.10-4.72, P = 0.0406), ankylosing spondylitis (SMD 0.78, 95% CI 0.23-1.33, P = 0.0052), inflammatory bowel disease (SMD 0.57, 95% CI 0.43-0.71, P <0.0001), psoriasis (SMD 0.98, 95% CI 0.62-1.34, P <0.0001), and Graves' disease (SMD 0.69, 95% CI 0.20-1.19, P = 0.0056). Circulating VEGF levels correlated with disease activity and hematological parameters in ADs.

Conclusion

Circulating VEGF levels were associated with ADs and could predict disease manifestations, severity and activity in patients with ADs.

Systematic Review Registration

PROSPERO, identifier CRD42021227843.

Origin and pathophysiology of protein carbonylation, nitration and chlorination in age-related brain diseases and aging

Non-enzymatic protein modifications occur inevitably in all living systems. Products of such modifications accumulate during aging of cells and organisms and may contribute to their age-related functional deterioration. This review presents the formation of irreversible protein modifications such as carbonylation, nitration and chlorination, modifications by 4-hydroxynonenal, removal of modified proteins and accumulation of these protein modifications during aging of humans and model organisms, and their enhanced accumulation in age-related brain diseases.

Vascular endothelial growth factor and soluble vascular endothelial growth factor receptor-1 in patients with end-stage renal disease. Associations with laboratory findings, comorbidities, and medications

Objectives:

To show the levels of vascular endothelial growth factor (VEGF), soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) in patients with end-stage renal disease (ESRD) and to show the associations with clinical findings such as demographic features, laboratory findings, comorbidities, and medications.

Methods:

A total of 73 people, consisting of patients with ESRD (n=38) and healthy subjects (n=35) in Gulhane Education and Research Hospital, Ankara, Turkey, were included in this cross-sectional study between the years 2011 and 2013. Blood samples were obtained and plasma VEGF, sVEGFR-1 analyzes were performed.

Results:

The VEGF level of ESRD group was not significantly higher (0.280±0.264) than the control group (0.321±0.210) (p=0.475). The sVEGFR-1 level of ESRD group was significantly higher (0.217±0.135) than the control group (0.068±0.047) (p<0.001). The correlation between VEGF and sVEGFR-1 was significant and negative (r=-0.246, p=0.036). Average VEGF level of ESRD patients using recombinant human erythropoietin (rhEPO) was significantly higher (0.567±0.28) than the ESRD patients not using rhEPO (0.246±0.24) (p=0.025).

Conclusion:

Our study is the first showing the significance of sVEGFR-1 in ESRD patients, and associations with comorbidities, medications. Especially our finding of rhEPO and VEGF may illuminate a reasonable positive effect of rhEPO on angiogenesis. Soluble vascular endothelial growth factor receptor-1 and VEGF may be important markers in the pathophysiology of ESRD.

Serum Soluble Vascular Cell Adhesion Molecule-1 Overexpression Is a Disease Marker in Patients with First-Time Diagnosed Antinuclear Antibodies: A Prospective, Observational Pilot Study

Objective

Antinuclear antibodies (ANA) serve as screening tests for connective tissue diseases but have low specificity. In this pilot study, we aimed to identify patients with first-time positive ANA and musculoskeletal complaints and correlate serum soluble vascular adhesion molecules as biomarkers.

Methods

Prospective, observational study with 100 ANA-positive patients, comparing them to age- and gender-matched healthy controls (HC, n = 75), was conducted. Serum levels of soluble intercellular adhesion molecule-1 (sICAM-1), endothelial-leukocyte adhesion molecule-1 (sELAM-1), and vascular cell adhesion molecule-1 (sVCAM-1) were measured. A subgroup of patients with systemic sclerosis (SSc) treated with immunosuppressants was followed over 10 months.

Results

Patients belonged to three main entities: rheumatoid arthritis (RA, n = 32), collagen diseases (CD, n = 56) also including systemic sclerosis (SSc, n = 11), and other autoimmune diseases (n = 12). sICAM-1 was similar among groups. sELAM-1 was elevated by 1.9-fold in only in SSc. sVCAM-1 was elevated by 3.1-fold in RA and by 3.3-fold in CD and in other autoimmune diseases by 3.4-fold. Seven SSc patients with immunosuppression had a 2.7-fold increased sVCAM-1 at baseline and reached the levels of healthy controls after 5 months, while CRP, ESR, and clinical parameters remained unchanged.

Conclusion

Our study suggests that sVCAM-1 is a disease marker independent of standard serum parameters in several rheumatic diseases. This study is registered with EU PAS Register number: EUPAS22154.

Increased Heme Oxygenase-1 and Nuclear Factor Erythroid 2-Related Factor-2 in the Placenta Have a Cooperative Action on Preeclampsia

BACKGROUND

Previous studies have shown that oxidative stress is an important factor in preeclampsia (PE). Heme oxygenase-1 (HO-1) and nuclear factor erythroid 2-related factor-2 (Nrf2) are protective proteins that are involved in combating oxidative stress in the body. Nrf2 is also an essential upstream transcription factor regulating HO-1. This study was aimed at exploring the physiological roles of HO-1 and Nrf2 in PE.

METHODS

Serum and placenta were collected from 30 patients who presented with severe PE and 30 healthy pregnant females. HO-1 and Nrf2 levels in placenta were measured. Following stimulation of the HTR-8/SVneo cell line with tert-butylhydroquinone (tBHQ), an Nrf2 activator, nuclear Nrf2 protein and HO-1 mRNA levels were determined.

RESULTS

Compared with the healthy pregnancy group, HO-1 protein and mRNA levels were increased in placental samples obtained from the severe PE group (p < 0.01, p < 0.05). Similar increases were also observed for Nrf2 protein levels (p < 0.01). Nuclear Nrf2 protein and HO-1 mRNA levels were both increased in the HTR-8/SVneo cell line following stimulation with tBHQ (p < 0.05).

CONCLUSION

Patients with severe PE may be protected against oxidative injury following an elevation in HO-1 and Nrf2 levels. Nrf2 is likely to have a synergistic effect on HO-1 in PE.

Fibrogenesis, novel lessons from animal models

Systemic sclerosis (SSc) is a devastating chronic autoimmune connective tissue disease characterized by vasculopathy, autoimmunity with inflammation, and progressive fibrogenesis. The current paradigm of the pathogenesis of SSc is that of an unknown initial trigger, leading to a complex interaction of immune cells, endothelial cells, and fibroblasts, producing cytokines, growth and angiogenic factors, and resulting in uncontrolled and persistent tissue fibrogenesis by an altered mesenchymal cell compartment. Animal models are of utmost importance to investigate the different steps in the pathogenesis. This review will elaborate on recent findings in established and more recently developed animal models, presenting data on compounds that are in or ready to be translated into clinical trials, or provide interesting new findings in the understanding of the pathophysiology of SSc. We focus on recent findings concerning the vessel-extracellular matrix interaction, the initial triggering aggressor, the concept of autoimmunity and inflammatory changes, the effector cells and their origins, and the complex interaction of the different signaling pathways in fibrogenesis.

Correlations between angiogenic factors and capillaroscopic patterns in systemic sclerosis

Introduction

We sought to assess whether nailfold videocapillaroscopy (NVC) patterns are associated with levels of angiogenic factors in systemic sclerosis (SSc).

Methods

Circulating endothelial progenitor cells (EPCs) and circulating endothelial cells (CECs) were measured in the peripheral blood of 60 consecutive SSc patients. Serum levels of eight endothelial markers were measured first in these 60 patients, and then in an independent replication cohort of 43 SSc patients in case of association with NVC patterns. NVC patterns were determined by four independent investigators blinded to vascular markers.

Results

Patients with the late-NVC pattern exhibited lower EPC levels (P < 0.0001) and higher VEGF levels (P = 0.03). Higher VEGF levels were confirmed to be associated with the late-NVC pattern in the replication cohort (P = 0.01). By multivariate analysis focused on biomarkers, lower EPC (P = 0.03) and higher VEGF levels (P = 0.001) were independently associated with the late-NVC pattern. In an alternate multivariate model including these two factors and SSc-related disease characteristics, lower EPC counts (P = 0.005), higher VEGF levels (P = 0.01), a history of digital ulcers (P = 0.04), and a modified Rodnan skin score > 14 (P < 0.0001) were independently associated with the late-NVC pattern.

Conclusion

Our data revealed decreased EPC counts and increased VEGF levels in patients with the late-NVC pattern. Further studies are now needed to determine the role of VEGF and EPCs in endothelial injury and repair in SSc.

Insights into the pathogenesis of systemic sclerosis based on the gene expression profile of progenitor-derived endothelial cells

OBJECTIVE

To determine the gene expression profile of endothelial cells derived from the endothelial progenitor cells (EPCs) of patients with systemic sclerosis (SSc).

METHODS

Microarray experiments were performed on Affymetrix GeneChip Human Exon 1.0 ST Arrays in unstimulated and hypoxia-stimulated EPC-derived cells from patients with SSc and control subjects. Followup of the raised hypotheses was performed ex vivo by immunohistochemical analysis of skin tissue.

RESULTS

Signals from 92 probe sets and 188 probe sets were different in unstimulated and hypoxia-stimulated cells, respectively, from patients with SSc compared with controls. Within the largest groups of genes related to cell-cell interaction and vascular remodeling, down-regulation of tumor necrosis factor ligand superfamily member 10 (TNFSF10) and homeobox A9 (HOX-A9) was confirmed by real-time polymerase chain reaction and Western blots in EPC-derived cells and by immunohistochemistry in SSc skin tissue. Signals from 221 and 307 probe sets were different in unstimulated and hypoxia-stimulated cells, respectively, from patients with diffuse cutaneous SSc compared with patients with limited cutaneous SSc. Within the largest group of genes related to the inflammatory response, differential expression of TNFα-induced protein 3 and prostaglandin-endoperoxide synthase 2 was observed in EPC-derived cells and skin tissue from patients with SSc.

CONCLUSION

Our data revealed important gene expression changes in EPC-derived endothelial cells from patients with SSc, characterized by a proadhesive, proinflammatory, and activated phenotype. Differential expression in lesional SSc skin tissue of new targets, such as TNF family members and HOX-A9, may contribute to the pathogenesis of SSc and deserves more in-depth exploration.

Scleroderma therapy: clinical overview of current trends and future perspective

Systemic sclerosis is a chronic autoimmune condition with a complex pathogenesis and a high rate of mortality and morbidity. Internal organ involvement requires interdisciplinary approach in individual patient management. New discoveries in the pathogenesis of scleroderma herald a drastic change in the traditional outlook to therapy and have led to the development of the target-based approach in management. The challenge at present is to translate these advances in molecular mechanisms into well-designed clinical trials that will recognize potential disease-modifying therapies. This article is an evidence-based review of prevailing treatment options and future therapeutic targets in systemic sclerosis.

High DNA Oxidative Damage in Systemic Sclerosis

Objective.

Several lines of evidence suggest that the generation of reactive oxygen species (ROS) is of major importance in the pathogenesis of SSc. Protein and lipid damage have previously been demonstrated, but scarce data are available on oxidative damage to DNA. In patients with SSc, we evaluated levels of 8-hydroxy-2’-deoxyguanosine (8-oxodG), the main validated biomarker of endogenous oxidative damage to DNA, compared to levels of F2-isoprostane, a product of free radical-mediated peroxidation of arachidonic acid.

Methods.

Urinary levels of 8-oxodG and 8-isoprostaglandin-F2α (8-iso-PGF2α) were determined by competitive ELISA method in consecutive SSc patients and controls matched for age and sex.

Results.

We included 80 unrelated SSc patients (72 women, mean age 56 ± 11 yrs) and 39 controls (33 women, mean age 64 ± 8 yrs). Urinary levels of 8-oxodG/creat and 8-iso-PGF2α/creat in SSc patients were found to be higher than in controls (6.5 ng/mg vs 3.7 ng/mg, p = 0.0001; and 11.4 ng/mg vs 4.2 ng/mg, p < 0.0001). In multivariate analysis, 8-oxodG levels were associated with the presence of pulmonary fibrosis on computerized tomography scan, decreased forced vital capacity, and decreased DLCO/alveolar volume. In patients with the diffuse cutaneous subset, a modified Rodnan skin score > 14 was independently associated with 8-oxodG levels. In SSc, 8-oxodG and 8-iso-PGF2α values were correlated (r = 0.32; p = 0.005).

Conclusion.

Our study confirmed marked oxidative stress in SSc. We also found increased values of 8-oxodG in SSc patients and a relevant association with a fibrotic phenotype. The predictive value of this marker and its potential influence on fibrotic disturbances remain to be determined.

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.

Mechanisms in the loss of capillaries in systemic sclerosis: angiogenesis versus vasculogenesis

Systemic sclerosis (SSc, scleroderma) is a chronic, multisystem connective tissue disorder affecting the skin and various internal organs. Although the disease is characterized by a triad of widespread microangiopathy, fibrosis and autoimmunity, increasing evidence indicates that vascular damage is a primary event in the pathogenesis of SSc. The progressive vascular injury includes persistent endothelial cell activation/damage and apoptosis, intimal thickening, delamination, vessel narrowing and obliteration. These profound vascular changes lead to vascular tone dysfunction and reduced capillary blood flow, with consequent tissue ischemia and severe clinical manifestations, such as digital ulceration or amputation, pulmonary arterial hypertension and scleroderma renal crisis. The resulting tissue hypoxia induces complex cellular and molecular mechanisms in the attempt to recover endothelial cell function and tissue perfusion. Nevertheless, in SSc patients there is no evidence of significant angiogenesis and the disease evolves towards chronic tissue ischemia, with progressive and irreversible structural changes in multiple vascular beds culminating in the loss of capillaries. A severe imbalance between pro-angiogenic and angiostatic factors may also lead to impaired angiogenic response during SSc. Besides insufficient angiogenesis, defective vasculogenesis with altered numbers and functional defects of bone marrow-derived endothelial progenitor cells may contribute to the vascular pathogenesis of SSc. The purpose of this article is to review the contribution of recent studies to the understanding of the complex mechanisms of impaired vascular repair in SSc. Indeed, understanding the pathophysiology of SSc-associated vascular disease may be the key in dissecting the disease pathogenesis and developing novel therapies. Either angiogenic or vasculogenic mechanisms may potentially become in the future the target of therapeutic strategies to promote capillary regeneration in SSc.

Upregulation of stromal cell derived factor-1alpha in collagen vascular diseases-associated interstitial pneumonias (CVDs-IPs)

OBJECTIVE

We speculated that distinct angiogenic profiles are involved in idiopathic interstitial pneumonias (IIPs) in comparison with interstitial pneumonias associated with collagen vascular disease (CVD-IPs). This hypothesis was investigated by measuring the expression of a cardinal biologic axis, the vascular endothelial growth factor (VEGF)-stromal derived growth factor [SDF-1alpha, transcripts 1 and 2 (TR1 and TR2)] and receptor, CXCR4 and the angiogenetic receptors CXCR2 and CXCR3 in bronchoalveolar lavage fluid (BALF) in both conditions.

METHODS

We studied prospectively 25 patients with fibrotic IIPs (f-IIPs) [20 with idiopathic pulmonary fibrosis (IPF) and 5 with idiopathic non-specific interstitial pneumonia (NSIP)] and 16 patients with CVD-IPs. mRNA expression was measured by Real-Time RT-PCR and protein was evaluated by Western Blotting.

RESULTS

A significantly greater value has been detected in SDF-1alpha-TR1 mRNA expression levels of CVD-IPs (p=0.05) in comparison with IPF group. A similar trend has been also detected in protein expression in favor of CVD-IP group. In addition, VEGF mRNA levels have been found significantly increased in CVD-IPs in comparison with the NSIP group (p=0.05). No significant difference has been found in SDF-1alpha-TR2-CXCR4 mRNA and CXCR2-CXCR3 between the two groups.

CONCLUSION

These results showed increased expression of SDF-1alpha in CVD-IPs, suggesting different angiogenic procedures. Further studies are needed in order to better explore the angiogenetic pathway in these disorders.

The proadhesive phenotype of systemic sclerosis skin promotes myeloid cell adhesion via ICAM-1 and VCAM-1

OBJECTIVE

SSc is characterized by microvascular abnormalities and leucocyte infiltration. Previous studies have suggested a proadhesive phenotype in SSc skin, but the functional consequences of this phenotype are not fully understood. Molecules known to mediate leucocyte adhesion include those present at intracellular junctions, such as junctional adhesion molecule-B (JAM-B), JAM-C and CD99, as well as intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). The aim of this study was to examine adhesive interactions in SSc skin.

METHODS

The expression of JAM-B, JAM-C, CD99, ICAM-1 and VCAM-1 in SSc skin was determined by immunohistology and cell surface ELISA. Myeloid U937 cell-SSc dermal fibroblast adhesion assays or in situ adhesion assays to SSc skin were performed.

RESULTS

JAM-C and CD99 expression on endothelial cells (ECs) in SSc skin was decreased compared with expression on normal ECs. CD99 was overexpressed on mononuclear cells in SSc skin and on SSc dermal fibroblasts. Neutralizing ICAM-1 inhibited the binding of U937 cells to SSc dermal fibroblasts. In addition, blocking both ICAM-1 and VCAM-1 inhibited U937 cell adhesion to either proximal (less involved) or distal (more involved) SSc skin.

CONCLUSIONS

These studies show that JAM-C and CD99 are aberrantly expressed in SSc skin. However, these adhesion molecules do not mediate myeloid cell-SSc skin adhesion. In contrast, we demonstrate an important role for ICAM-1 and VCAM-1 in the retention of myeloid cells in SSc skin, suggesting that targeting these molecules may be useful SSc therapies.

Angiogenesis in systemic sclerosis: impaired expression of vascular endothelial growth factor receptor 1 in endothelial progenitor-derived cells under hypoxic conditions

OBJECTIVE

To assess angiogenesis and explore the expression and regulation of vascular endothelial growth factor (VEGF), VEGF receptor 1 (VEGFR-1), and VEGFR-2, the leading mediators of angiogenesis, in SSc patients and controls.

METHODS

Late-outgrowth endothelial progenitor cells (EPCs), isolated from the peripheral blood of systemic sclerosis (SSc) patients and controls, and human umbilical vein endothelial cells (HUVECs) were assessed under normal and hypoxic conditions. Genomic background was evaluated in a large case-control study (including 659 patients with SSc and 511 controls) using tag single-nucleotide polymorphisms on VEGFR1 and VEGFR2 genes.

RESULTS

EPCs from SSc patients had the phenotype of genuine endothelial cells and displayed in vitro angiogenic properties similar to those of HUVECs and control EPCs under basal conditions, as determined by flow cytometry, tube formation, and migration assay. However, after 6 hours of hypoxic exposure, EPCs from SSc patients exhibited lower induced expression of VEGFR-1 at the messenger RNA and protein levels, but similar VEGF and VEGFR-2 expression, compared with HUVECs or EPCs from healthy controls. There was no evidence of defective expression of hypoxia-inducible factor 1alpha. These results were supported by the lower serum levels of soluble VEGFR-1 found in SSc patients (n = 187) compared with healthy controls (n = 48) (mean +/- SD 163.7 +/- 98.5 versus 210.4 +/- 109.5 pg/ml; P = 0.0042). These abnormalities did not seem to be related to genomic background.

CONCLUSION

Our findings shed new light on the possible role of VEGFR-1 in the main vascular disturbances that occur in SSc and lead to more severe disease.

Disturbed angiogenesis in systemic sclerosis: high levels of soluble endoglin

OBJECTIVE

SSc is a CTD characterized by early generalized microangiopathy with disturbed angiogenesis. Soluble endoglin (sENG), a serum anti-angiogenic protein, has recently been described as a major actor in pre-eclampsia, another severe vascular disease with abnormal angiogenesis. The aim of this study was to investigate, in a cross-sectional study, sENG levels together with other serum vascular markers.

METHODS

Serum levels of sENG were assessed by ELISA in consecutive SSc patients and controls matched for age and sex. We also measured by ELISA serum levels of VEGF and asymmetric dimethylarginine (ADMA), as respective markers of angiogenesis and endothelial dysfunction.

RESULTS

We included 235 unrelated subjects: 187 SSc patients and 48 controls. Higher concentrations of sENG (P = 0.002) and sVEGF (P < 0.0001) were found in SSc patients compared with controls whereas there was no difference for ADMA. In multivariate analysis, sENG levels were significantly increased in SSc patients with cutaneous ulcerations (P = 0.0003), positive for ACAs (P = 0.009) and with abnormal diffusing capacity for carbon monoxide divided by alveolar volume (P = 0.03). Soluble ENG levels negatively correlated with ADMA, but no relationship was found between sENG and sVEGF.

CONCLUSION

This study shows increased values of sENG in a large SSc cohort and a relevant association with a vascular phenotype. The predictive value of the biomarker sENG and its potential role on cellular endothelial disturbances remain to be determined.

Genetic basis for systemic sclerosis

Among the connective tissue diseases, systemic sclerosis is an orphan disease in which diffuse connective tissue alterations lead to multi-organ involvement. Environmental factors implicated in triggering this multifactorial disease include crystalline silica, chlorine solvents, welding vapors, and various other solvents. Clustering within families indicates a role for genetic factors. Although concordance for the disease among identical twins is low, concordance for autoantibodies associated with systemic sclerosis and for fibroblast gene expression profiles is higher. Because multiplex families are rare, association and candidate gene strategies are the most appropriate methods for investigating the genetics of systemic sclerosis. The most consistent data relate to the involvement of fibrosis genes, most notably the TGF-beta regulation pathway, secreted protein acid and rich in cysteine (SPARC) genes, and the fibrillin-1 gene (FBN1). Several variants of genes for cytokines or their receptors may be involved. Data on the vasculopathy characteristic of systemic sclerosis are somewhat conflicting. Investigations into the genetics of systemic sclerosis may shed light on the complex pathophysiology of this disease, help to identify factors that predict organ involvement, and suggest new treatment strategies.

Vasculopathy and disordered angiogenesis in selected rheumatic diseases: rheumatoid arthritis and systemic sclerosis

Angiogenesis is important in the pathogenesis of systemic inflammatory rheumatic diseases, a family of related disorders that includes rheumatoid arthritis and systemic sclerosis. Rheumatoid arthritis is the rheumatic disease in which the role of angiogenesis has been studied most extensively. However, whereas rheumatoid arthritis is characterized by excessive angiogenesis, the situation is not as clear cut in other rheumatic diseases. For example, systemic sclerosis is characterized by reduced capillary density with insufficient angiogenic responses. Results with angiogenesis inhibitors are controversial, and there is – in parallel – a wide range of upregulated angiogenic factors such as vascular endothelial growth factor. Dysregulation of angiogenesis in systemic sclerosis is accompanied by other pathogenic processes, including fibrosis, autoimmunity and vasculopathy. Animal models with at least partial features of the vasculopathy observed in systemic sclerosis include wound healing models, graft versus host disease models and, in particular, the University of California at Davis line 200 chicken model of systemic sclerosis.

Effects of D-4F on vasodilation, oxidative stress, angiostatin, myocardial inflammation, and angiogenic potential in tight-skin mice

Systemic sclerosis (scleroderma, SSc) is an autoimmune, connective tissue disorder that is characterized by impaired vascular function, increased oxidative stress, inflammation of internal organs, and impaired angiogenesis. Tight skin mice (Tsk−/+) have a defect in fibrillin-1, resulting in replication of many of the myocardial and vascular features seen in humans with SSc. D-4F is an apolipoprotein A-I (apoA-I) mimetic that improves vascular function in diverse diseases such as hypercholesterolemia, influenza, and sickle cell disease. Tsk−/+ mice were treated with either phosphate-buffered saline (PBS) or D-4F (1 mg·kg−1·day−1 for 6–8 wk). Acetylcholine and flow-induced vasodilation were examined in facialis arteries. Proinflammatory HDL (p-HDL) in murine and human plasma samples was determined by the cell-free assay. Angiostatin levels in murine and human plasma samples were determined by Western blot analysis. Hearts were examined for changes in angiostatin and autoantibodies against oxidized phosphotidylcholine (ox-PC). Angiogenic potential in thin sections of murine hearts was assessed by an in vitro vascular endothelial growth factor (VEGF)-induced endothelial cell (EC) tube formation assay. D-4F improved endothelium-, endothelial nitric oxide synthase-dependent, and flow-mediated vasodilation in Tsk−/+ mice. Tsk−/+ mice had higher plasma p-HDL and angiostatin levels than C57BL/6 mice, as did SSc patients compared with healthy control subjects. Tsk−/+ mice also had higher triglycerides than C57BL/6 mice. D-4F reduced p-HDL, angiostatin, and triglycerides in the plasma of Tsk−/+ mice. Tsk−/+ hearts contained notably higher levels of angiostatin and autoantibodies against ox-PC than those of control hearts. D-4F ablated angiostatin in Tsk−/+ hearts and reduced autoantibodies against ox-PC by >50% when compared with hearts from untreated Tsk−/+ mice. Angiogenic potential in Tsk−/+ hearts was increased only when the Tsk−/+ mice were treated with D-4F (1 mg·kg−1·day−1, 6–8 wk), and cultured sections of hearts from the D-4F-treated Tsk−/+ micewere incubated with D-4F (10 μg/ml, 5–7 days). Failure to treat the thin sections of hearts and Tsk−/+ mice with D-4F resulted in loss of VEGF-induced EC tube formation. D-4F improves vascular function, decreases myocardial inflammation, and restores angiogenic potential in the hearts of Tsk−/+ mice. As SSc patients have increased plasma p-HDL and angiostatin levels similar to the Tsk−/+ mice, D-4F may be effective at treating vascular complications in patients with SSc.

Vascular Endothelial Growth Factor (VEGF) in Autoimmune Diseases

Vascular endothelial growth factor (VEGF) is a potent stimulating factor for angiogenesis and vascular permeability. There are eight isoforms with different and sometimes overlapping functions. The mechanisms of action are under investigation with emerging insights into overlapping pathways and cross-talk between other receptors such as the neuropilins, which were not previously associated to angiogenesis. VEGF has important physiological actions on embryonic development, healing, and menstrual cycle. It also has a great role in pathological conditions that are associated to autoimmune diseases. There is considerable evidence in various autoimmune diseases such as in systemic lupus erythematosus, rheumatoid arthritis, and multiple sclerosis of an interrelationship between the VEGF system and theses disorders. Serum levels of VEGF correlate with disease activity in a large number of autoimmune diseases and fall with the use of standard therapy. We raised the possible future therapeutic strategies in autoimmune diseases with the anti-VEGF or anti-VEGFR (receptor). So far, this therapy has been used in cancer and macular ocular degeneration in diabetes. This review outlines the evidence for VEGF participation in various autoimmune diseases and proposes lines for future research in this field.

Prognostic markers for systemic sclerosis

The prognosis of systemic sclerosis depends chiefly on the extent of the skin lesions, which correlates with the severity of the cardiovascular, pulmonary, and renal manifestations. An erythrocyte sedimentation rate greater than 15-25 mm/h or a hemoglobin level lower than 12.5-11 g/dl is associated with a 2.5- to 3-fold increase in mortality. Anticentromere antibodies are associated with delayed pulmonary hypertension, anti-topoisomerase I antibodies (Scl 70) with interstitial lung disease, and anti-RNA polymerase III antibodies with renovascular hypertension. The risk of death is directly related to the autoantibody pattern. For instance, in a study of 1432 cases from the Pittsburgh Scleroderma Databank, 10-year survival among patients with limited cutaneous disease was 88% in the group with anti-U1-RNP, 75% in the group with anticentromere antibodies, 72% in the group with anti-PmScl, and 65% in the group with anti-Th/To. Ten-year survival in patients with diffuse cutaneous disease was 64% with anti-topoisomerase antibodies, 61% with anti-U3-RNP, and 75% with anti-RNA polymerase III. Several prognostic markers are also available for predicting the risk of organ involvement. For instance, serum levels of KL-6, surfactant proteins SP-A and SP-D, the collagen peptide PIIINP, and homocysteine are associated with the risk of fibrosing alveolitis. Serum levels of CD40L and NP-ProBNP, circulating endothelial cells, and serum anticardiolipin titers correlate with the risk of arterial hypertension. Serum VCAM1 and markers for oxidative stress such as carboxyl terminus residues predict the risk of vascular disease. Other serum markers for organ involvement are under study, although their predictive performance remains to be evaluated.

Treatment of systemic sclerosis

Systemic sclerosis is the most severe of all connective tissue diseases. The distinctive pathogenic process involves sequential or concomitant abnormalities in blood vessel function, immunity and, ultimately, fibroblast function. These specific characteristics may explain the results of treatment evaluations. The decrease in excess mortality shown in recent studies seems chiefly ascribable to the use of cardiovascular drugs. Angiotensin-converting enzyme (ACE) inhibitors are effective in resolving renal crisis, prostacyclins and endothelin antagonists improve pulmonary hypertension, and calcium antagonists and ACE inhibitors benefit patients with myocardial involvement. On the other hand, immunomodulatory drugs and other agents investigated for their disease-modifying potential failed to influence skin fibrosis in controlled trials. Trials of immunosuppressants are ongoing. Available results indicate that emphasis should be put on cardiovascular drugs. The development of criteria for disease activity and severity would facilitate future research on the treatment of systemic sclerosis.

Lack of association between three vascular endothelial growth factor gene polymorphisms and systemic sclerosis: results from a multicenter EUSTAR study of European Caucasian patients

INTRODUCTION

Systemic sclerosis (SSc) is characterised by disturbed vessel morphology and an overproduction of vascular endothelial growth factor (VEGF). The VEGF gene located on chromosome 6p21.3 has several polymorphisms.

OBJECTIVE

To test the hypothesis that disturbed angiogenesis may be related to the genetic background of the VEGF gene.

MATERIALS AND METHODS

EUSTAR centres included European Caucasian patients with SSc and matched controls with osteoarthritis. The VEGF gene was genotyped by polymerase chain reaction, followed by restriction enzyme analysis. The 634 C/T and 936 C/G mutations and an 18-base pair insertion/deletion at -2549 of the VEGF promoter region were tested.

RESULTS

416 patients with SSc and 249 controls were included in the study population. Of the patients with SSc, 42% had a diffuse cutaneous subtype, 16% had increased pulmonary arterial pressure and 61% had decreased carbon monoxide diffusion capacity. The genotype frequencies in the patients with SSc and in controls were in Hardy-Weinberg equilibrium. The allele and genotype frequencies of the polymorphisms did not differ between patients with SSc and controls. No association was found between these polymorphisms and disease phenotypes.

CONCLUSION

This study shows that there is no association between the three selected functional VEGF polymorphisms and SSc.

Nifedipine protects against overproduction of superoxide anion by monocytes from patients with systemic sclerosis

We have reported previously that dihydropyridine-type calcium-channel antagonists (DTCCA) such as nifedipine decrease plasma markers of oxidative stress damage in systemic sclerosis (SSc). To clarify the cellular basis of these beneficial effects, we investigated the effects in vivo and in vitro of nifedipine on superoxide anion (O₂^•-) production by peripheral blood monocytes. We compared 10 healthy controls with 12 patients with SSc, first after interruption of treatment with DTCCA and second after 2 weeks of treatment with nifedipine (60 mg/day). O₂^•- production by monocytes stimulated with phorbol myristate acetate (PMA) was quantified by the cytochrome c reduction method. We also investigated the effects in vitro of DTCCA on O₂^•- production and protein phosphorylation in healthy monocytes and on protein kinase C (PKC) activity using recombinant PKC. After DTCCA had been washed out, monocytes from patients with SSc produced more O₂^•- than those from controls. Nifedipine treatment considerably decreased O₂^•- production by PMA-stimulated monocytes. Treatment of healthy monocytes with nifedipine in vitro inhibited PMA-induced O₂^•- production and protein phosphorylation in a dose-dependent manner. Finally, nifedipine strongly inhibited the activity of recombinant PKC in vitro. Thus, the oxidative stress damage observed in SSc is consistent with O₂^•- overproduction by primed monocytes. This was decreased by nifedipine treatment both in vivo and in vitro. This beneficial property of nifedipine seems to be mediated by its cellular action and by the inhibition of PKC activity. This supports the hypothesis that this drug could be useful for the treatment of diseases associated with oxidative stress.