Maria Letizia Conforti

Overexpression of VEGF165b, an Inhibitory Splice Variant of Vascular Endothelial Growth Factor, Leads to Insufficient Angiogenesis in Patients With Systemic Sclerosis

Rationale: Systemic sclerosis (SSc) is characterized by widespread microangiopathy, fibrosis, and autoimmunity. Despite the lack of angiogenesis, the expression of vascular endothelial growth factor A (VEGF) was shown to be upregulated in SSc skin and circulation; however, previous studies did not distinguish between proangiogenic VEGF165 and antiangiogenic VEGF165b isoforms, which are generated by alternative splicing in the terminal exon of VEGF pre-RNA. Objective: We investigated whether VEGF isoform expression could be altered in skin and circulation of patients with SSc. Methods and Results: Here, we show that the endogenous antiangiogenic VEGF165b splice variant is selectively overexpressed at both the mRNA and protein levels in SSc skin. Elevated VEGF165b expression correlated with increased expression of profibrotic transforming growth factor-&bgr;1 and serine/arginine protein 55 splicing factor in keratinocytes, fibroblasts, endothelial cells, and perivascular inflammatory cells. Circulating levels of VEGF165b were significantly higher in patients with SSc than in control subjects. Microvascular endothelial cells (MVECs) isolated from SSc skin expressed and released higher levels of VEGF165b than healthy MVECs. Transforming growth factor-&bgr;1 upregulated the expression of VEGF165b and serine/arginine protein 55 in both SSc and healthy MVECs. In SSc MVECs, VEGF receptor-2 was overexpressed, but its phosphorylation was impaired. Recombinant VEGF165b and SSc-MVEC–conditioned medium inhibited VEGF165-mediated VEGF receptor-2 phosphorylation and capillary morphogenesis in healthy MVECs. The addition of anti-VEGF165b blocking antibodies abrogated the antiangiogenic effect of SSc-MVEC–conditioned medium. Capillary morphogenesis was severely impaired in SSc MVECs and could be ameliorated by treatment with recombinant VEGF165 and anti-VEGF165b blocking antibodies. Conclusions: In SSc, a switch from proangiogenic to antiangiogenic VEGF isoforms may have a crucial role in the insufficient angiogenic response to chronic ischemia.

High prevalence of polymorphisms of angiotensin-converting enzyme (I/D) and endothelial nitric oxide synthase (Glu298Asp) in patients with systemic sclerosis

PURPOSE Systemic sclerosis is characterized by progressive microvascular occlusion and fibrosis and by an imbalance in the fibrinolytic system. In vivo and in vitro studies suggest that the renin-angiotensin system partly regulates vascular fibrinolytic balance. Angiotensin II increases the production and secretion of plasminogen activator inhibitor-1, while angiotensin-converting enzyme (ACE) contributes to reduced production of tissue plasminogen activator and endothelial nitric oxide synthesis by bradykinin degradation. The aim of our study was to investigate the effects of ACE insertion/deletion (I/D) and endothelial nitric oxide synthase (eNOS) Glu298Asp (G894-->T) and T-786-->C polymorphisms in patients with systemic sclerosis. SUBJECTS AND METHODS We studied 73 consecutive patients (47 with limited and 26 with diffuse cutaneous systemic sclerosis) and 112 control subjects. ACE I/D and eNOS polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis. RESULTS The ACE I/D and the eNOS G894-->T polymorphisms were more common in patients than in controls (for the ACE D allele: odds ratio [OR] = 3.4; 95% confidence interval [CI]: 1.5 to 7.9; P = 0.003; for the eNOS T allele: OR = 1.9; 95% CI: 1.0 to 3.4; P = 0.04). There was no association between the eNOS T-786-->C polymorphism and systemic sclerosis. CONCLUSIONS Our findings of an increased risk of systemic sclerosis in ACE D and eNOS 894T allele carriers suggest that these polymorphisms may contribute to the pathogenesis of the disease.

Autologous stem cell transplantation improves microcirculation in systemic sclerosis

Background: In systemic sclerosis (SSc) reduced capillary density decreases blood flow and leads to tissue ischaemia and fingertip ulcers. Nail fold videocapillaroscopy (NVC) is a diagnostic and follow-up parameter useful to evaluate the severity, activity and the stage of SSc microvascular damage. Autologous haemopoietic stem cell transplantation (HSCT) is a new treatment for patients with severe diffuse cutaneous systemic sclerosis (dcSSc) refractory to conventional therapies. We aimed to evaluate the improvement of microvasculature after HSCT using NVC. Methods: A total of 16 patients with severe dcSSc with a “late” videocapillaroscopy pattern underwent an immunesuppressive treatment: 6 were treated with HSCT and 10 with monthly pulse cyclophosphamide (CYC) 1 g for 6 months and then orally with 50 mg/day for further 6 months. NVC was performed before and after 3 months from the beginning of each treatment and then repeated every 3 months. Results: In all patients, before HSCT NVC showed large avascular areas and ramified capillaries and vascular architectural disorganisation (“late” pattern). At 3 months after HSCT, the NVC pattern changed from “late” into “active”, showing frequent giant capillaries (>6/mm) and haemorrhages, absence of avascular areas and angiogenesis phenomena; 1 year after HSCT, microvascular abnormalities were still in the “active” pattern. In patients treated with CYC, no NVC modifications were observed during 24 months of follow-up and the pattern always remained “late”. Conclusions: These results indicate that HSCT with a high dose CYC regimen may foster vascular remodelling, while CYC at lower doses and with a chronic regimen does not influence the microvasculature.

Lung CT Densitometry in Systemic Sclerosis: Correlation With Lung Function, Exercise Testing, and Quality of Life

BACKGROUND To ascertain if analysis of lung density histograms in thin-section CT was more reproducible than visual assessment of lung changes in systemic sclerosis (SSc), and if such density histogram parameters as mean lung attenuation (MLA), skewness, and kurtosis could more closely reflect pulmonary function as well as exercise and quality of life impairment. METHODS The intraoperator and interoperator reproducibility of visual and densitometric lung CT analysis in 48 SSc patients examined with CT were evaluated by means of weighted kappa statistics. Univariate and multivariate regression analyses were applied to evaluate the relationship of visual and densitometric CT measurements with functional parameters including functional residual capacity (FRC), FVC, FEV(1), diffusion capacity of the lung for carbon monoxide (Dlco), 6-min walking testing (6MWT), and health-related quality of life questionnaire (QLQ) parameters. RESULTS The intraoperator and interoperator reproducibility of MLA (intraobserver weighted kappa = 0.97; interobserver weighted kappa = 0.96), skewness (intraobserver weighted kappa = 0.89; interobserver weighted kappa = 0.88), and kurtosis (intraobserver weighted kappa = 0.89; interobserver weighted kappa = 0.88) were higher than those of visual assessment (intraobserver weighted kappa = 0.71; interobserver weighted kappa = 0.69). In univariate analysis, only densitometric measurements were correlated with some exercise and QLQ parameters. In multivariate analysis, MLA (square regression coefficient corrected [R(2)c] = 0.70), skewness (R(2)c = 0.78), and kurtosis (R(2)c = 0.77) were predicted by FRC, FVC, Dlco, 6MWT, and QLQ parameters, while visual assessment was associated only with FRC and FVC (R(2)c = 0.40). CONCLUSIONS In SSc, densitometric analysis is more reproducible than visual assessment of lung changes in thin-section CT and more closely correlated to pulmonary function testing, 6MWT, and QLQ. Density histogram parameters may be useful for cross-sectional and longitudinal studies of lung involvement in SSc.

The IL1-like cytokine IL33 and its receptor ST2 are abnormally expressed in the affected skin and visceral organs of patients with systemic sclerosis

Background Early endothelial cell (EC) activation/damage and profibrotic Th2-associated cytokines play a pivotal role in systemic sclerosis (SSc). Interleukin 33 (IL33) is a novel member of the IL1 family that promotes Th2 responses and inflammation through the ST2 receptor. IL33 is also a chromatin-associated transcriptional regulator in ECs. Objective To investigate the role of the IL33/ST2 axis in SSc. Methods Skin biopsies were obtained from 30 patients with SSc (15 early/15 late stage) and 10 healthy subjects. Lung, kidney, heart, oesophagus, stomach, placenta biopsies and bronchoalveolar lavage cells from patients with SSc and controls were also analysed. IL33/ST2 expression was investigated by immunohistology, confocal immunofluorescence microscopy, western blotting and RT-PCR. Results In skin biopsies from control subjects, constitutive nuclear IL33 protein expression was found in dermal ECs and keratinocytes, while ST2 was weakly expressed in ECs and fibroblasts. In skin biopsies from patients with early SSc, IL33 protein was downregulated or absent in ECs and epidermis while IL33 mRNA was normally expressed or even upregulated. Moreover, ECs, perivascular infiltrating mast cells, CD68-positive macrophages, CD3-positive T cells, CD20-positive B cells and activated fibroblasts/myofibroblasts exhibited strong ST2 expression. In skin biopsies from patients with late SSc, IL33 was constitutively found in most ECs while ST2 immunostaining was weaker. In early SSc, the loss of endothelial IL33 protein and the overexpression of ST2 involved all affected organs. Dermal and pulmonary fibroblasts showed IL33 expression in SSc. Conclusion IL33 and ST2 are abnormally expressed in SSc. In early SSc, upon EC activation/damage IL33 may be mobilised from ECs to signal through ST2 in key profibrotic players such as inflammatory/immune cells and fibroblasts/myofibroblasts.

Intravenous immunoglobulins improve the function and ameliorate joint involvement in systemic sclerosis: a pilot study

Background: In systemic sclerosis (SSc), joint involvement may reduce the functional capacity of the hands. Intravenous immunoglobulins have previously been shown to benefit patients with SSc. Aim: To verify the efficacy of intravenous immunoglobulins on joint involvement and function in SSc. Patients and methods: 7 women with SSc, 5 with limited and 2 with diffuse SSc, with a severe and refractory joint involvement were enrolled in the study. Methotrexate and cyclophosphamide pulse therapy did not ameliorate joint symptoms. Hence, intravenous immunoglobulins therapy was prescribed at a dosage of 2 g/kg body weight during 4 days/month for six consecutive courses. The presence of joint tenderness and swelling, and articular deformities (due to primary joint involvement and not due to skin and subcutaneous changes) were evaluated. Before and after 6 months of treatment, patients were subjected to (1) Ritchie Index (RI) evaluation of joint involvement; (2) Dreiser Algo-Functional Index (IAFD) evaluation of hand joint function; (3) pain visual analogue scale (VAS) to measure joint pain; (4) Health Assessment Questionnaire (HAQ) to evaluate the limitations in everyday living and physical disability; and (5) modified Rodnan Skin Score for skin involvement. Results: After 6 months of intravenous immunoglobulins therapy, joint pain and tenderness, measured with the VAS, decreased significantly (p<0.03), and hand function (IAFD) improved significantly (p<0.02), together with the quality of life (HAQ; p<0.03). All patients significantly improved, except for one. The skin score after 6 months of intravenous immunoglobulins therapy was significantly reduced (p<0.003). Conclusion: This pilot study suggests that intravenous immunoglobulins may reduce joint pain and tenderness, with a significant recovery of joint function in patients with SSc with severe and refractory joint involvement. The cost of intravenous immunoglobulins might limit their use only to patients who failed disease-modifying antirheumatic drugs.

Bone marrow-derived mesenchymal stem cells from early diffuse systemic sclerosis exhibit a paracrine machinery and stimulate angiogenesis in vitro

Objective To characterise bone marrow-derived mesenchymal stem cells (MSCs) from patients with systemic sclerosis (SSc) for the expression of factors implicated in MSC recruitment at sites of injury, angiogenesis and fibrosis. The study also analysed whether the production/release of bioactive mediators by MSCs were affected by stimulation with cytokines found upregulated in SSc serum and tissues, and whether MSCs could modulate dermal microvascular endothelial cell (MVEC) angiogenesis. Methods MSCs obtained from five patients with early severe diffuse SSc (SSc-MSCs) and five healthy donors (H-MSCs) were stimulated with vascular endothelial growth factor (VEGF), transforming growth factor β (TGFβ) or stromal cell-derived factor-1 (SDF-1). Transcript and protein levels of SDF-1 and its receptor CXCR4, VEGF, TGFβ1 and receptors TβRI and TβRII were evaluated by quantitative real-time PCR, western blotting and confocal microscopy. VEGF, SDF-1 and TGFβ1 secretion in culture supernatant was measured by ELISA. MVEC capillary morphogenesis was performed on Matrigel with the addition of MSC-conditioned medium. Results In SSc-MSCs the basal expression of proangiogenic SDF-1/CXCR4 and VEGF was significantly increased compared with H-MSCs. SSc-MSCs constitutively released higher levels of SDF-1 and VEGF. SDF-1/CXCR4 were upregulated after VEGF stimulation and CXCR4 redistributed from the cytoplasm to the cell surface. VEGF was increased by SDF-1 challenge. VEGF, TGFβ and SDF-1 stimulation upregulated TGFβ1, TβRI and TβRII in SSc-MSCs. TβRII redistributed from the cytoplasm to focal adhesion contacts. SSc-MSC-conditioned medium showed a greater proangiogenic effect on MVECs than H-MSCs. Experiments with blocking antibodies showed that MSC-derived cytokines were responsible for this potent proangiogenic effect. Conclusion SSc-MSCs constitutively overexpress and release bioactive mediators/proangiogenic factors and potentiate dermal MVEC angiogenesis.

Flow‐Mediated Vasodilation and Carotid Intima‐Media Thickness in Systemic Sclerosis

Abstract:  Increased evidence suggests an accelerated macrovascular disease in systemic sclerosis (SSc). Brachial artery flow‐mediated vasodilation (FMD) and carotid intima‐media thickness (IMT) are two indicators of subclinic cardiovascular disease and are frequently used as surrogate measures of subclinic atherosclerosis. The aim of this study was to evaluate macrovascular involvement in SSc. We studied 35 SSc patients (6 males and 29 females; 11 with diffuse and 24 with limited disease) and 20 healthy controls. Brachial artery FMD was assessed by method described by Celermajer in all patients and 13 control subjects. IMT was measured using high‐resolution B‐mode ultrasonography in patients and controls. Traditional risk factors for atherosclerosis (hypertension, dyslipidemia, and smoke) were also assessed. FMD was significantly impaired (3.41%± 4.56% versus 7.66%± 4.24%; P < 0.037) and IMT was significantly elevated compared with healthy controls (0.93 ± 0.29 mm versus 0.77 ± 0.13 mm; P < 0.005). FMD was not significantly different in SSc with increased IMT compared with those with normal IMT). No correlation was found between risk factors for atherosclerosis and the impairment of FMD or IMT in SSc patients. The impairment of endothelial function and structural changes of large vessels are evident in SSc, but do not seem associated with traditional risk factors for atherosclerosis. Prospective studies including also clinical outcomes are needed to assess the features and significance of macrovacular involvement in SSc.

Increased serum levels and tissue expression of matrix metalloproteinase-12 in patients with systemic sclerosis: correlation with severity of skin and pulmonary fibrosis and vascular damage

Objective To determine serum concentrations and tissue expression of matrix metalloproteinase-12 (MMP-12) and their correlation with clinical features in patients with systemic sclerosis (SSc). Methods Serum MMP-12 levels from 72 patients with SSc and 42 healthy volunteers were examined by ELISA. Immunohistochemical expression of MMP-12 was analysed in skin biopsies from 20 patients with SSc and 13 healthy subjects and lung biopsies from three patients with SSc-related interstitial lung disease (ILD) and five controls. Results Circulating levels of MMP-12 were significantly increased in patients with SSc compared with healthy controls. Serum MMP-12 levels were significantly higher in both patients with limited cutaneous SSc and those with diffuse cutaneous SSc than in healthy controls, and correlated positively with the extent of skin involvement. MMP-12 levels were raised in SSc patients with ILD compared with patients without ILD, and correlated with severity of lung restriction. Increased serum levels of MMP-12 were also associated with the presence of digital ulcers and severity of nailfold capillary abnormalities. In contrast to almost undetectable MMP-12 expression in healthy skin, MMP-12 was strongly expressed in keratinocytes, dermal endothelial cells, fibroblasts/myofibroblasts and inflammatory cells in the skin of patients with SSc. Affected lung tissue from patients with SSc-related ILD showed strong MMP-12 expression in capillary vessels, inflammatory cells, alveolar macrophages and fibroblasts in the thickened alveolar septa, while faint expression was observed in normal lung tissue. Conclusions MMP-12 levels are increased in patients with SSc and are associated with severity of skin and pulmonary fibrosis and peripheral vascular damage.

Lung ultrasound for the screening of interstitial lung disease in very early systemic sclerosis

Background A high percentage of patients with systemic sclerosis (SSc) develop interstitial lung disease (ILD) during the course of the disease. Promising data have recently shown that lung ultrasound (LUS) is able to detect ILD by the evaluation of B-lines (previously called ultrasound lung comets), the sonographic marker of pulmonary interstitial syndrome. Objective To evaluate whether LUS is reliable in the screening of ILD in patients with SSc. Methods Fifty-eight consecutive patients with SSc (54 women, mean age 51±14 years) who underwent a high resolution CT (HRCT) scan of the chest were also evaluated by LUS for detection of B-lines. Of these, 32 patients (29 women, mean age 51±15 years) fulfilled the criteria for a diagnosis of very early SSc. Results At HRCT, ILD was detected in 88% of the SSc population and in 41% of the very early SSc population. A significant difference in the number of B-lines was found in patients with and without ILD on HRCT (57±53 vs 9±9; p<0.0001), with a concordance rate of 83%. All discordant cases were false positive at LUS, providing a sensitivity and negative predictive value of 100% in both SSc and very early SSc. Conclusions ILD may be detected in patients with very early SSc. The presence of B-lines at LUS examination correlates with ILD at HRCT. LUS is very sensitive for detecting ILD even in patients with a diagnosis of very early SSc. The use of LUS as a screening tool for ILD may be feasible to guide further investigation with HRCT.