RESUMEN
Atherosclerosis, is a chronic inflammatory disease, characterized by the narrowing of the arteries resulting from the formation of intimal plaques in the wall of arteries. Yet the molecular mechanisms responsible for maintaining the development and progression of atherosclerotic lesions have not been fully defined. In this study, we show that TGF-ß activates the endothelial-to-mesenchymal transition (EndMT) in cultured human aortic endothelial cells (HAECs) and this transition is dependent on the key executor of the Wnt signaling pathway in vitro. This study presents the first evidence describing the mechanistic details of the TGF-ß-induced EndMT signaling pathway in HAECs by documenting the cellular transition to the mesenchymal phenotype including the expression of mesenchymal markers α-SMA and PDGFRα, and the loss of endothelial markers including VE-cadherin and CD31. Furthermore, a short hairpin RNA (shRNA) screening revealed that Wnt2 signaling is required for TGF-ß-mediated EndMT of HAECs. Also, we found that LDLR-/- mice fed on a high-fat western-type diet (21% fat, 0.2% cholesterol) expressed high levels of Wnt2 protein in atherosclerotic lesions, confirming that this signaling pathway is involved in atherosclerosis in vivo. These findings suggest that Wnt2 may contribute to atherosclerotic plaque development and this study will render Wnt2 as a potential target for therapeutic intervention aiming at controlling atherosclerosis.
RESUMEN
BACKGROUND: Pharmacoinvasive therapy for the treatment of ST elevation myocardial infarction (STEMI) is a strategy that combines early restoration of coronary flow via pharmacologically induced thrombolysis with subsequent, prompt percutaneous coronary intervention (PCI). Prior studies suggesting a heightened bleeding risk of PCI performed early after fibrinolysis predated contemporary pharmacoinvasive practice including use of femoral closure devices (CD), fibrin specific thrombolytics, lower doses of heparin and stents. METHODS: Consecutive patients were included in this retrospective registry study if they underwent emergent PCI for ST elevation myocardial infarction (STEMI) followed by immediate use of a groin closure device. Between Oct 1, 2002 and Jan 1, 2003, 27 patients were treated with immediate use of CD after post-thrombolytic PCI, performed within 12 hours of thrombolysis (pharmacoinvasive group). 58 patients were treated with immediate use of CD after primary PCI for STEMI. The two groups were compared with respect to the incidence of successful groin closure, bleeding complications, and clinical outcomes. Bleeding events were categorized according to the TIMI criteria. All baseline clinical and treatment variables were compared between the two groups to determine and the association of these variables (including use of thromblytic therapy) with TIMI major and TIMI minor bleeding was determined. RESULTS: Pharmacoinvasive recanalization with PCI occurred 348 +/- 183 minutes after initiation of fibrinolytic therapy. Glycoprotein IIb/IIIa inhibitors were used less frequently in the patients treated with a thrombolytic agent (59% vs. 90%, p < 0.01). Successful immediate hemostasis was obtained with CD in greater than 85% of patients in both groups (89% for pharmacoinvasive group vs. 86% for primary PCI group, p = 0.89). No patient required vascular surgical intervention. TIMI major bleeding and transfusion requirements were less than 5% in both groups. Antecedent thrombolytic therapy was not a predictor of bleeding complications after PCI. CONCLUSIONS: Use of CD as part of a contemporary pharmacoinvasive strategy is associated with a low rate of major bleeding complications.
