Dysbalance of angiogenic and angiostatic mediators in patients with mixed connective tissue disease

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Cellular and Molecular Diversity in Scleroderma

With the increasing armamentarium of high-throughput tools available at manageable cost, it is attractive and informative to determine the molecular underpinnings of patient heterogeneity in systemic sclerosis (SSc). Given the highly variable clinical outcomes of patients labelled with the same diagnosis, unravelling the cellular and molecular basis of disease heterogeneity will be crucial to predicting disease risk, stratifying management and ultimately informing a patient-centered precision medicine approach. Herein, we summarise the findings of the past several years in the fields of genomics, transcriptomics, and proteomics that contribute to unraveling the cellular and molecular heterogeneity of SSc. Expansion of these findings and their routine integration with quantitative analysis of histopathology and imaging studies into clinical care promise to inform a scientifically driven patient-centred personalized medicine approach to SSc in the near future.

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.

Biomarker profiles of endothelial activation and dysfunction in rare systemic autoimmune diseases: implications for cardiovascular risk

OBJECTIVES

Vasculopathy is an important hallmark of systemic chronic inflammatory connective tissue diseases (CICTD) and is associated with increased cardiovascular risk. We investigated disease-specific biomarker profiles associated with endothelial dysfunction, angiogenic homeostasis and (tissue) inflammation, and their relation to disease activity in rare CICTD.

METHODS

A total of 38 serum proteins associated with endothelial (dys)function and inflammation were measured by multiplex-immunoassay in treatment-naive patients with localized scleroderma (LoS, 30), eosinophilic fasciitis (EF, 8) or (juvenile) dermatomyositis (34), 119 (follow-up) samples during treatment, and 65 controls. Data were analysed by unsupervised clustering, Spearman correlations, non-parametric t test and ANOVA.

RESULTS

The systemic CICTD, EF and dermatomyositis, had distinct biomarker profiles, with 'signature' markers galectin-9 (dermatomyositis) and CCL4, CCL18, CXCL9, fetuin, fibronectin, galectin-1 and TSP-1 (EF). In LoS, CCL18, CXCL9 and CXCL10 were subtly increased. Furthermore, dermatomyositis and EF shared upregulation of markers related to interferon (CCL2, CXCL10), endothelial activation (VCAM-1), inhibition of angiogenesis (angiopoietin-2, sVEGFR-1) and inflammation/leucocyte chemo-attraction (CCL19, CXCL13, IL-18, YKL-40), as well as disturbance of the Angiopoietin-Tie receptor system and VEGF-VEGFR system. These profiles were related to disease activity, and largely normalized during treatment. However, a subgroup of CICTD patients showed continued elevation of CXCL10, CXCL13, galectin-9, IL-18, TNFR2, VCAM-1, and/or YKL-40 during clinically inactive disease, possibly indicating subclinical interferon-driven inflammation and/or endothelial dysfunction.

CONCLUSION

CICTD-specific biomarker profiles revealed an anti-angiogenic, interferon-driven environment during active disease, with incomplete normalization under treatment. This warrants further investigation into monitoring of vascular biomarkers during clinical follow-up, or targeted interventions to minimize cardiovascular risk in the long term.

VEGF (Vascular Endothelial Growth Factor) and Fibrotic Lung Disease

Interstitial lung disease (ILD) encompasses a group of heterogeneous diseases characterised by varying degrees of aberrant inflammation and fibrosis of the lung parenchyma. This may occur in isolation, such as in idiopathic pulmonary fibrosis (IPF) or as part of a wider disease process affecting multiple organs, such as in systemic sclerosis. Anti-Vascular Endothelial Growth Factor (anti-VEGF) therapy is one component of an existing broad-spectrum therapeutic option in IPF (nintedanib) and may become part of the emerging therapeutic strategy for other ILDs in the future. This article describes our current understanding of VEGF biology in normal lung homeostasis and how changes in its bioavailability may contribute the pathogenesis of ILD. The complexity of VEGF biology is particularly highlighted with an emphasis on the potential non-vascular, non-angiogenic roles for VEGF in the lung, in both health and disease.

Impaired angiogenesis as a feature of digital ulcers in systemic sclerosis

Impaired angiogenesis in systemic sclerosis has a major role in tissue injury pathogenesis. Our objective was to determine whether angiogenic biomarkers (vascular endothelial growth factor (VEGF), endoglin, and endostatin) are related to microvascular damage and to determine their predictive value for new digital ulcers (DU). The main outcome of the study was the occurrence of a new digital ulcer during 3-year follow-up. This prospective longitudinal study was performed between October 2011 and December 2014. Seventy-seven patients definitely diagnosed with systemic sclerosis where divided into two groups: those with active DU at baseline and those with no DU until enrollment. Patients were matched by sex and age with healthy controls. Serum levels of VEGF, endoglin, and endostatin were measured at enrollment, and several nailfold videocapillaroscopies were performed during the 3-year follow-up. Serum levels of VEGF were lower (245.06, 158.68-347.33; p < 0.001) and those of endoglin were higher (3.013, 1.463-7.023; p < 0.001) in patients with active DU than those with no DU history (339.49, 202.00-730.93/1.879, 0.840-3.280), and they were higher than those found in controls (178.030, 101.267-222.102)/0.277, 0.154-0.713), respectively. No differences in endostatin levels were found between groups (p = 0.450). Endoglin was the only biomarker significantly different (p = 0.031) between patients with diffuse versus limited systemic sclerosis and between early, active, and late patterns (p = 0.020). VEGF was identified as an independent predictor for the development of new DU. Our study confirmed the relationship between angiogenic vascular biomarkers and the occurrence of DU. Endoglin and VEGF serum levels are potential risk factors, and VEGF has a predictive value for the occurrence of new DU.

Associations between anti-Ro52 antibodies and lung fibrosis in mixed connective tissue disease

OBJECTIVE

MCTD is a chronic, immune-mediated disorder defined by the combined presence of serum anti-RNP antibodies and distinct clinical features, including progressive lung fibrosis. The aim of the study was to evaluate the potential impact of anti-SSA (i.e. Ro52 and Ro60) and anti-SSB autoantibodies as markers for disease outcomes in MCTD.

METHODS

Stored serum samples from 113 patients included in the cross-sectional, nationwide Norwegian MCTD cohort were screened for the presence of anti-Ro52, anti-Ro60 and anti-SSB by a commercial line immunoassay. Correlation analyses were carried out with clinical parameters, including quantitative lung fibrosis scores by high-resolution CT. Lung fibrosis was defined by reticular pattern changes according to the Fleischner Society CT criteria for interstitial lung disease.

RESULTS

Anti-Ro52 antibodies were present in 29%, anti-Ro60 in 19% and anti-SSB in 6% of the MCTD sera. High-resolution CT scoring identified lung fibrosis in 38 of 113 (34%) MCTD patients. Anti-Ro52 antibodies were detected in 50% (19 of 38) of the MCTD patients with lung fibrosis and in 19% (14 of 75) without lung fibrosis (P < 0.001). The odds ratio for the presence of anti-Ro52 antibodies in lung fibrosis was 4.4 (95% CI 1.8, 10.3). Anti-Ro52 antibodies were equally frequent in patients with mild to moderate (eight of 17; 44%) and severe fibrosis (11 of 21; 52%). Anti-Ro52 was not associated with any of the other clinical parameters assessed, nor was anti-Ro60 or anti-SSB.

CONCLUSION

Our cross-sectional data suggest that anti-Ro52 antibodies may serve as a potential marker for lung fibrosis in MCTD.

Associations between circulating endostatin levels and vascular organ damage in systemic sclerosis and mixed connective tissue disease: an observational study

Introduction

Systemic sclerosis (SSc) and mixed connective tissue disease (MCTD) are chronic immune-mediated disorders complicated by vascular organ damage. The aim of this study was to examine the serum levels of the markers of neoangiogenesis: endostatin and vascular endothelial growth factor (VEGF), in our unselected cohorts of SSc and MCTD.

Methods

Sera of SSc patients (N = 298) and MCTD patients (N = 162) from two longitudinal Norwegian cohorts were included. Blood donors were included as controls (N = 100). Circulating VEGF and endostatin were analyzed by enzyme immunoassay.

Results

Mean endostatin levels were increased in SSc patients 93.7 (37) ng/ml (P < .001) and MCTD patients 83.2 (25) ng/ml (P < .001) compared to controls 65.1 (12) ng/ml. Median VEGF levels were elevated in SSc patients 209.0 (202) pg/ml compared to MCTD patients 181.3 (175) pg/ml (P = .017) and controls 150.0 (145) pg/ml (P < .001). Multivariable analysis of SSc subsets showed that pulmonary arterial hypertension (coefficient 15.7, 95 % CI: 2.2–29.2, P = .023) and scleroderma renal crisis (coefficient 77.6, 95 % CI: 59.3–100.0, P < .001) were associated with elevated endostatin levels. Multivariable analyses of MCTD subsets showed that digital ulcers were associated with elevated endostatin levels (coefficient 10.5, 95 % CI: 3.2–17.8, P = .005). The risk of death increased by 1.6 per SD endostatin increase (95 % CI: 1.2–2.1, P = .001) in the SSc cohort and by 1.6 per SD endostatin increase (95 % CI: 1.0–2.4, P = .041) in the MCTD cohort after adjustments to known risk factors.

Conclusions

Endostatin levels were elevated in patients with SSc and MCTD, particularly SSc patients with pulmonary arterial hypertension and scleroderma renal crisis, and MCTD patients with digital ulcers. Elevated endostatin levels were also associated with increased all-cause mortality during follow-up in both groups of patients. We propose that endostatin might indicate the degree of vascular injury in SSc and MCTD patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0756-5) contains supplementary material, which is available to authorized users.

Inactivation of autophagy ameliorates glucocorticoid-induced and ovariectomy-induced bone loss

OBJECTIVES

Autophagy has recently been shown to regulate osteoclast activity and osteoclast differentiation. Here, we aim to investigate the impact of autophagy inhibition as a potential therapeutic approach for the treatment of osteoporosis in preclinical models.

METHODS

Systemic bone loss was induced in mice by glucocorticoids and by ovariectomy (OVX). Autophagy was targeted by conditional inactivation of autophagy-related gene 7 (Atg7) and by treatment with chloroquine (CQ). Bone density was evaluated by microCT. The role of autophagy on osteoclastogenesis was analysed by osteoclastogenesis and bone resorption assays. The quantification of receptor activator of nuclear factor κ B ligand and osteoprotegerin proteins in cocultures was performed using ELISA whereas that of osteoclast and osteoblast differentiation markers was by qPCR.

RESULTS

Selective deletion of Atg7 in monocytes from Atg7(fl/fl)_x_LysM-Cre mice mitigated glucocorticoid-induced and OVX-induced osteoclast differentiation and bone loss compared with Atg7(fl/fl) littermates. Pharmacological inhibition of autophagy by treatment with CQ suppressed glucocorticoid-induced osteoclastogenesis and protected mice from bone loss. Similarly, inactivation of autophagy shielded mice from OVX-induced bone loss. Inhibition of autophagy led to decreased osteoclast differentiation with lower expression of osteoclast markers such as NFATc1, tartrate-resistant acid phosphatase, OSCAR and cathepsin K and attenuated bone resorption in vitro. In contrast, osteoblast differentiation was not affected by inhibition of autophagy.

CONCLUSIONS

Pharmacological or genetic inactivation of autophagy ameliorated glucocorticoid-induced and OVX-induced bone loss by inhibiting osteoclastogenesis. These findings may have direct translational implications for the treatment of osteoporosis, since inhibitors of autophagy such as CQ are already in clinical use.

The right ventricle in scleroderma (2013 Grover Conference Series)

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

Do nutritional supplements have a role in age macular degeneration prevention?

Purpose. To review the proposed pathogenic mechanisms of age macular degeneration (AMD), as well as the role of antioxidants (AOX) and omega-3 fatty acids ( ω -3) supplements in AMD prevention. Materials and Methods. Current knowledge on the cellular/molecular mechanisms of AMD and the epidemiologic/experimental studies on the effects of AOX and ω -3 were addressed all together with the scientific evidence and the personal opinion of professionals involved in the Retina Group of the OFTARED (Spain). Results. High dietary intakes of ω -3 and macular pigments lutein/zeaxanthin are associated with lower risk of prevalence and incidence in AMD. The Age-Related Eye Disease study (AREDS) showed a beneficial effect of high doses of vitamins C, E, beta-carotene, and zinc/copper in reducing the rate of progression to advanced AMD in patients with intermediate AMD or with one-sided late AMD. The AREDS-2 study has shown that lutein and zeaxanthin may substitute beta-carotene because of its potential relationship with increased lung cancer incidence. Conclusion. Research has proved that elder people with poor diets, especially with low AOX and ω -3 micronutrients intake and subsequently having low plasmatic levels, are more prone to developing AMD. Micronutrient supplementation enhances antioxidant defense and healthy eyes and might prevent/retard/modify AMD.

Upregulation of VEGF expression is associated with accumulation of HIF-1α in the skin of naïve scleroderma patients

Systemic sclerosis is a disease hallmarked by microangiopathy; the enlargement and leakage of skin capillaries in active stages develops into extensive avascular areas, clinically associated with severe tissue hypoxia and the formation of digital ulcers. Vascular endothelial growth factor (VEGF) is upregulated in all stages of the disease, with little effect on efficient neovascularization. The oxygen-regulated α-subunit of hypoxia-inducible transcription factor-1 (HIF-1α) represents a key mechanism involved in the transcriptional regulation of VEGF. The aim of this study is to investigate expression of the oxygen-regulated α-subunit of HIF-1 and VEGF in naïve scleroderma patients. For this purpose, skin biopsies (dorsal hand surface) from scleroderma patients were analyzed and compared with control skin biopsies. Immunoreactivity for VEGF was enhanced in scleroderma patients, in contrast to restricted positive immunostaining in suprabasal keratinocytes observed in normal skin. In a similar fashion, all skin biopsies from scleroderma patients were strongly HIF-1α reactive, compared with rare immunoreactivity observed in normal skin. The pattern was similar in all stages of scleroderma. These observations for the first time directly connect constitutive hypoxia with VEGF upregulation in scleroderma patients. The sequence of events needs to be precisely mapped, and the pro- and antiangiogenic switches which may interfere with efficient tissue neovascularization identified, in order to provide meaningful therapeutic strategies.