Raised LIGHT levels in pulmonary arterial hypertension: potential role in thrombus formation.
ABSTRACT Thrombus formation and inflammation are involved in the pathogenesis of pulmonary arterial hypertension (PAH), and LIGHT (Lymphotoxin-like Inducible protein that competes with Glycoprotein D for Herpesvirus entry mediator on T lymphocytes) has been shown to promote vascular inflammation.
We sought to investigate the role of the tumor necrosis factor superfamily ligand LIGHT in the pathogenesis of PAH.
We studied 73 patients with severe PAH and 10 control subjects. LIGHT and pro- and antithrombotic markers were assessed by enzyme immunoassays.
(1) Patients with idiopathic PAH (n = 21), patients with PAH related to risk factors or associated conditions (n = 31), and those with chronic thromboembolic PAH (n = 21) all had raised serum levels of LIGHT compared with control subjects (n = 10). (2) LIGHT levels in femoral artery were significantly related to mortality in the patients with PAH. (3) Immunostaining of LIGHT and its receptors was seen in alveolar macrophages, vascular smooth muscle cells, and endothelial cells in lungs from patients with PAH. (4) Thirteen patients received prostacyclin infusion (3 mo), and all showed hemodynamic improvement, accompanied by decreased LIGHT levels. (5) Prostacyclin abolished the release of LIGHT from activated platelets in vitro, suggesting that the decrease in LIGHT during prostacyclin therapy could involve direct effects on platelets. (6) LIGHT increased tissue factor and plasminogen activator inhibitor type 1 and decreased thrombomodulin levels in endothelial cells, inducing a prothrombotic state in these cells.
Our findings suggest prothrombotic effects of LIGHT in PAH involving endothelium-related mechanisms, potentially contributing to the progression of this disorder.
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ABSTRACT: Increasing evidence supports a role for inflammation in chronic heart failure (CHF). However, the source and the mechanism for this immune activation are unknown. To address this issue we investigated the gene expression of cytokines and the surface expression of activity markers in T-cells and monocytes from CHF patients and healthy controls. Gene expression of cytokines was analysed by real-time RT-PCR and activation markers by flow cytometry in 14 CHF patients and nine healthy controls. Surface expression of activation markers for T-cells and monocytes were analysed by flow cytometry. T-cells from CHF patients showed enhanced gene expression of chemokines, ligands in the tumor necrosis factor superfamily, as well as the inflammatory cytokines interferon-gamma and interleukin-18 with similar pattern in ischemic (n=5) and idiopathic cardiomyopathy (n=9). In contrast, no differences in cytokine gene expression were found comparing monocytes from CHF patients and controls. Moreover, T-cells from CHF patients had enhanced surface expression of the activation markers CD69 and CD25, while there was no upregulation of the monocyte activation marker CD32 in these patients. T-cells may be a part of the inflammatory response during CHF independent of the etiology of the disorder. Intervention preventing unwanted T-cell activation could represent a new target in the treatment of CHF.Cardiovascular Research 11/2003; 60(1):141-6. · 5.94 Impact Factor
- Journal of Laboratory and Clinical Medicine 08/1998; 132(1):16-24. · 2.62 Impact Factor
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ABSTRACT: Patients with primary pulmonary hypertension (PPH) benefit from treatment with anticoagulants, and histological findings suggest that in situ thrombosis of pulmonary vessels contributes to the pathogenesis of this disease. The mechanisms that cause a hypercoagulable state in the pulmonary vascular bed have not been fully investigated. This study compared plasminogen plasma activity, protein C and protein S plasma activities, fibrinogen and fibrin degradation products (FGDP and FBDP, respectively), von Willebrand factor antigen (vWF-Ag), prothrombin fragment F1.2, thrombin-antithrombin complexes (TAT), tissue plasminogen activator (tPA), and plasminogen activator inhibitor (PAI) in 16 patients with PPH and in 16 healthy volunteers. In a subset of the PPH patients, these variables were also compared in simultaneously-obtained mixed-venous and arterial blood samples. Proteins C and S, FGDP, FBDP, and plasminogen levels as well as plasma concentrations of prothrombin fragment F1.2 and TAT were normal in the 16 patients with PPH. In contrast, the plasma activity of PAI was significantly elevated (p<0.0001). Arterial PAI levels were considerably higher than mixed venous PAI levels (p=0.0018), which may reflect intrapulmonary production. Furthermore, vWF-Ag levels were significantly elevated (p<0.0001), but there was no significant difference between mixed-venous and arterial blood. These data, on the whole, do not suggest increased thrombin activity in patients with primary pulmonary hypertension. However, the markedly elevated levels of plasminogen activator inhibitor as well as its transpulmonary gradient may provide a clue to locally impaired fibrinolysis in the pulmonary vascular bed.European Respiratory Journal 01/1999; 12(6):1446-9. · 6.36 Impact Factor