Eloisa Romano

Relationship between high platelet turnover and platelet function in high-risk patients with coronary artery disease on dual antiplatelet therapy

A high platelet turnover rate produce a population of immature reticulated platelets (RP) that could confer, despite of antiplatelet drugs, a residual platelet reactivity (RPR) in coronary artery disease (CAD) patients. To assess the influence of RP on platelet reactivity in CAD patients on dual antiplatelet therapy we measured RP in 372 patients by using the Sysmex XE-2100 haematology analyzer and platelet function by optical platelet aggregometry (PA) on platelet-rich-plasma induced by 1 mmol arachidonic acid (AA-PA) and 10 microM ADP (ADP-PA). RPR was defined as either AA-PA>20% or ADP-PA>70%. RP were expressed as a percentage of RP of the total optical platelet count (immature platelet fraction; IPF) and as the percentage of RP highly fluorescent (highly fluorescent immature platelet fraction; H-IPF). Moderate but significant positive correlations between PA, IPF, H-IPF, and mean platelet volume (MPV) were found. According to tertiles of IPF, H-IPF and MPV, a significant trend for an increase of platelet aggregation by AA and ADP was evidenced. Furthermore, a significant difference for IPF, H-IPF and MPV between patients with and without RPR was observed. A linear regression analysis showed that IPF, H-IPF and MPV significantly affected PA measured by AA and ADP. At multivariate linear regression analysis these associations were confirmed. Moreover, a logistic regression analysis demonstrated that IPF, H-IPF and MPV significantly influenced the risk of RPR, and in the multivariate model these results remained significant. This study indicates that a high rate of platelet turnover is a new mechanism associated with platelet reactivity in high risk CAD patients on dual antiplatelet therapy.

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.

Assessment of platelet function on whole blood by multiple electrode aggregometry in high-risk patients with coronary artery disease receiving antiplatelet therapy.

This study sought to compare Multiplate impedance platelet aggregometry (IPA) with light transmission aggregometry (LTA) and the PFA-100 for determining the prevalence of residual platelet reactivity (RPR) by the Multiplate IPA in 297 patients with acute coronary syndrome receiving dual antiplatelet therapy. Aggregations were induced by adenosine-5 diphosphate (ADP), arachidonic acid, and collagen. PFA-100 closure times were measured by collagen and ADP and epinephrine (CEPI) cartridges. Significant correlations were observed between Multiplate IPA and LTA after all stimulations (P < .0001) and between Multiplate IPA (arachidonate and collagen) and PFA-100 CEPI closure time (P < .0001 for both). Cutoff values of Multiplate IPA (for all stimulations) were calculated for the identification of RPR. Between the Multiplate IPA and LTA good agreement was found with all 3 agonists (P < .0001 for all). Multiplate IPA might represent a reliable, handy, rapid tool to monitor antiplatelet therapy in clinical practice and for clinical investigations.

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.

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.

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.

Comparison of different methods to evaluate the effect of aspirin on platelet function in high-risk patients with ischemic heart disease receiving dual antiplatelet treatment.

Patients with coronary artery disease (CAD) receiving aspirin therapy with a residual platelet reactivity (RPR) may be at increased risk of ischemic vascular events. Point-of-care (POC) methods PFA-100 (Dade-Behring, Marburg, Germany) and VerifyNow (Accumetrics, San Diego, CA) assays have been suggested as rapid tools to evaluate RPR. We compared PFA-100 closure times by collagen/epinephrine and VerifyNow Aspirin assays with light transmission aggregation (LTA) induced by 1 mmol/L of arachidonic acid in 484 patients with CAD undergoing percutaneous coronary intervention and receiving dual antiplatelet therapy. RPR was detected in 30.0% of patients by LTA, in 32.4% by PFA-100, and in 14.3% by VerifyNow. Significant correlations were found among 3 methods (all P < .0001). In relation to the presence or absence of RPR by LTA and PFA-100, by LTA and VerifyNow, and by PFA-100 and VerifyNow, samples were significantly concordant (all P < .0001). Assuming LTA as the reference method, PFA-100 and VerifyNow showed sensitivity of 62.1% and 39.3% and specificity of 80.2% and 96.4%, respectively. The cutoff values for POC methods need to be defined for clinical use.

Vascular biomarkers and correlation with peripheral vasculopathy in systemic sclerosis.

Vascular disease is a hallmark of systemic sclerosis (SSc). It is present in every patient, being responsible both for the earliest clinical manifestations and the major life-threatening complications of the disease, and thus determining important morbidity and mortality. In SSc, progressive vascular injury leads to vascular tone dysfunction and reduced capillary blood flow, with consequent tissue ischemia and chronic hypoxia. These phenomena are often accompanied by abnormal levels of vascular factors. Microangiopathy in SSc may be easily assessed by nailfold videocapillaroscopy. The variety of derangements detected in the nailfold capillaries is accompanied by abnormal levels of different vascular mediators and appears to be the best evaluable predictor of the development of peripheral vascular complications, such as digital ulcers. The purpose of this review is to summarize in SSc the most relevant vascular biomarkers and the main associations between vascular biomarkers and capillaroscopic parameters and/or the presence of digital ulcers. Vascular biomarkers could become useful predictive factors of vascular damage in SSc, allowing an earlier management of vascular complications.

Increased plasma levels of the VEGF165b splice variant are associated with the severity of nailfold capillary loss in systemic sclerosis

In systemic sclerosis (SSc), Raynauds phenomenon is the earliest clinical manifestation paralleled by nailfold capillaroscopic alterations that may occur months or even years before the onset of fibrosis.1 This evidence suggests a crucial role of microangiopathy characterised by a progressive loss of capillaries with the formation of avascular areas.1 ,2 Consequent chronic tissue hypoxia leads to skin ulcers and gangrene that heavily burden patients’ quality of life.1 ,2 Vascular endothelial growth factor-A (VEGF-A) is overexpressed in SSc skin, and increased circulating levels of VEGF-A correlate with the severity of nailfold capillary loss.2–4 It has been demonstrated that the VEGF-A primary transcript can be alternatively spliced in its terminal exon, producing two distinct mRNA splice variants that are translated to the proangiogenic VEGF165 and antiangiogenic VEGF165b isoforms.5 These two isoforms bind to the tyrosine kinase receptor VEGFR-2 with the same affinity, but binding of VEGF165b results in an insufficient tyrosine phosphorylation/activation of VEGFR-2 and incomplete or transient downstream signalling, which lead to an impaired angiogenic response.5 ,6 Recently, we have provided the first evidence that dermal expression and plasma levels of VEGF165b are raised in SSc patients, and VEGF165b overexpression prevents SSc dermal microvascular endothelial …

Differential expression of junctional adhesion molecules in different stages of systemic sclerosis.

OBJECTIVE Systemic sclerosis (SSc) is characterized by early perivascular inflammation, microvascular endothelial cell (MVEC) activation/damage, and defective angiogenesis. Junctional adhesion molecules (JAMs) regulate leukocyte recruitment to sites of inflammation and ischemia-reperfusion injury, vascular permeability, and angiogenesis. This study was undertaken to investigate the possible role of JAMs in SSc pathogenesis. METHODS JAM-A and JAM-C expression levels in skin biopsy samples from 25 SSc patients and 15 healthy subjects were investigated by immunohistochemistry and Western blotting. Subcellular localization of JAMs in cultured healthy dermal MVECs and SSc MVECs was assessed by confocal microscopy. Serum levels of soluble JAM-A (sJAM-A) and sJAM-C in 64 SSc patients and 32 healthy subjects were examined by enzyme-linked immunosorbent assay. RESULTS In control skin, constitutive JAM-A expression was observed in MVECs and fibroblasts. In early-stage SSc skin, JAM-A expression was strongly increased in MVECs, fibroblasts, and perivascular inflammatory cells. In late-stage SSc, JAM-A expression was decreased compared with controls. JAM-C was weakly expressed in control and late-stage SSc skin, while it was strongly expressed in MVECs, fibroblasts, and inflammatory cells in early-stage SSc. Surface expression of JAM-A was higher in early-stage SSc MVECs and increased in healthy MVECs stimulated with early-stage SSc sera. JAM-C was cytoplasmic in resting healthy MVECs, while it was recruited to the cell surface upon challenge with early-stage SSc sera. Early-stage SSc MVECs exhibited constitutive surface JAM-C expression. In SSc, increased levels of sJAM-A and sJAM-C correlated with early disease and measures of vascular damage. CONCLUSION Our findings indicate that JAMs may participate in MVEC activation, inflammatory processes, and impaired angiogenesis in different stages of SSc.