Long-term clinical outcomes of everolimus-eluting bioresorbable scaffolds versus everolimus-eluting stents:final five-year results of the AIDA randomised clinical trial

Background: Absorb bioresorbable vascular scaffold (BVS)-related events have been reported between 1 and 3 years – the period of active scaffold bioresorption. Data on the performance of the Absorb BVS in daily clinical practice beyond this time point are scarce. Aims: This report aimed to provide the final five-year clinical follow-up of the Absorb BVS in comparison with the XIENCE everolimus-eluting stent (EES). In addition, we evaluated the effect of prolonged dual antiplatelet therapy (DAPT) administration on events in the scaffold group. Methods: AIDA was a multicentre, investigator-initiated, non-inferiority trial, in which 1,845 unselected patients with coronary artery disease were randomly assigned to either the Absorb BVS (n=924) or the XIENCE EES (n=921). Target vessel failure (TVF), a composite of cardiac death, target vessel myocardial infarction or target vessel revascularisation, was the primary endpoint. Scaffold thrombosis cases were matched with controls and tested for the effect of prolonged DAPT. Results: Up to five-year follow-up, there was no difference in TVF between the Absorb BVS (17.7%) and the XIENCE EES (16.1%) (hazard ratio [HR] 1.31, 95% confidence interval [CI]: 0.90-1.41; p=0.302). Definite or probable device thrombosis (DT) occurred in 43 patients (4.8%) in the scaffold group compared to 13 patients (1.5%) in the stent group (HR 3.32, 95% CI: 1.78-6.17; p<0.001). DT between 3 and 4 years occurred six times in the Absorb arm versus three times in the XIENCE arm. Between 4 and 5 years, the incidence was three versus two, respectively. Of those three DT in the scaffold group, two occurred in XIENCE EES-treated lesions. The odds ratio of scaffold thrombosis in patients on DAPT compared to off DAPT throughout five-year follow-up was 0.36 (95% CI: 0.15-0.86). Conclusions: The excess risk of the Absorb BVS on late adverse events, in particular device thrombosis, in routine PCI continues up to 4 years and seems to plateau afterwards

Orphan nuclear receptor Nur77 affects cardiomyocyte calcium homeostasis and adverse cardiac remodelling

Distinct stressors may induce heart failure. As compensation, β-adrenergic stimulation enhances myocardial contractility by elevating cardiomyocyte intracellular Ca2+ ([Ca2+]i). However, chronic β-adrenergic stimulation promotes adverse cardiac remodelling. Cardiac expression of nuclear receptor Nur77 is enhanced by β-adrenergic stimulation, but its role in cardiac remodelling is still unclear. We show high and rapid Nur77 upregulation in cardiomyocytes stimulated with β-adrenergic agonist isoproterenol. Nur77 knockdown in culture resulted in hypertrophic cardiomyocytes. Ventricular cardiomyocytes from Nur77-deficient (Nur77-KO) mice exhibited elevated diastolic and systolic [Ca2+]i and prolonged action potentials compared to wild type (WT). In vivo, these differences resulted in larger cardiomyocytes, increased expression of hypertrophic genes

Less bleeding by omitting aspirin in non-ST-segment elevation acute coronary syndrome patients: Rationale and design of the LEGACY study

BACKGROUND: Early aspirin withdrawal, also known as P2Y12-inhibitor monotherapy, following percutaneous coronary intervention (PCI) for non-ST-segment elevation acute coronary syndrome (NSTE-ACS) can reduce bleeding without a trade-off in efficacy. Still the average daily bleeding risk is highest during the first months and it remains unclear if aspirin can be omitted immediately following PCI. METHODS: The LEGACY study is an open-label, multicenter randomized controlled trial evaluating the safety and efficacy of immediate P2Y12-inhibitor monotherapy versus dual antiplatelet therapy (DAPT) for 12 months in 3,090 patients. Patients are randomized immediately following successful PCI for NSTE-ACS to 75-100 mg aspirin once daily versus no aspirin. The primary hypothesis is that immediately omitting aspirin is superior to DAPT with respect to major or minor bleeding defined as Bleeding Academic Research Consortium type 2, 3, or 5 bleeding, while maintaining noninferiority for the composite of all-cause mortality, myocardial infarction and stroke compared to DAPT. CONCLUSIONS: The LEGACY study is the first randomized study that is specifically designed to evaluate the impact of immediately omitting aspirin, and thus treating patients with P2Y12-inhibitor monotherapy, as compared to DAPT for 12 months on bleeding and ischemic events within 12 months following PCI for NSTE-ACS

Plasminogen activator inhibitor 1 and vitronectin protect against stenosis in a murine carotid artery ligation model

Objective-We previously reported that plasminogen activator inhibitor I (PAI-1), in the presence of vitronectin (VN), inhibits thrombin activity in vitro. Furthermore, we demonstrated in human atherosclerotic plaques the colocalization of thrombin, PAI-1, and VN, as well as activity of thrombin and PAI-1. Here, we show that PAI-1 is a local thrombin inhibitor in vivo. Methods and Results-We used the murine carotid artery ligation model to assess the role of PAI-I and VN in stenosis by using PAI-1-deficient (PAI-1(-/-)) and VN-/- mice. Ligation resulted in a smooth muscle cell (SMC)-rich intima without infiltrating cells. We show that PAI-1(-/-) and VN-/- mice generate a larger intima than wild-type mice as the result of more extensive SMC proliferation, as evidenced by cell counting and staining for proliferating cell-nuclear antigen. Conclusions-In PAI-1(-/-) mice, excessive intima formation is prevented by the thrombin-specific inhibitor hirudin. Finally, immunohistochemical analysis revealed PAI-I, VN, and (pro)thrombin antigen in intimal lesions. Our observations are compatible with inhibition of thrombin-mediated SMC proliferation by PAI-1/VN complexe

Focusing on transcription factor families in atherogenesis: the function of LKLF and TR3

In this overview, two separate studies are discussed that emerged from a "discovery-driven" approach to identify genes that play an essential role in atherogenesis. First, by a combination of DNA micro-array and one-way linkage hierachical clustering, we selected genes that are induced in endothelial cells (EC) by prolonged steady- or pulsatile laminar flow, but of which expression is not affected by inflammatory and mitogenic agents (TGF-beta, IL- Ibeta TNF-alpha,VEGF, thrombin). The genes selected accordingly were: cytochrome P450 I B 1, diaphorase and the transcription factor lung Kruppel-like factor (LKLF) of which only the latter is truly EC specific. LKLF meets the criteria of an anti-atherosclerotic gene, mainly since expression is restricted to areas subjected to laminar flow as shown by in situ hybridization with anatomically well-defined specimens. Second, neointimal (but not medial) smooth muscle cells (SMC) specifically synthesize the NGFI-B subfamily (TR3, MINOR, NOT) of the nuclear hormone superfamily of transcription factors. Again, evidence is presented, indicating that these proteins serve an anti-atherosclerotic function. Notably, transgenic mice, expressing either TR3 or a dominant-negative mutant TR3DeltaTA in arterial SMC, were subjected to carotid artery ligation to induce SMC proliferation. Lesions in TR3-overexpressing transgenic mice were 5-fold smaller than isogenic wild-type mice, while mice overexpressing the TR3DeltaTA mutant had a 3-fold larger lesion. It is proposed that (down-stream products of) TR3 inhibit the cell cycle, since adenovirus-mediated expression of TR3DeltaTA and TR3, respectively, inhibit and promote the synthesis of the cyclin-dependent kinase inhibitor p27(Kipl) in SM

Protective function of transcription factor TR3 orphan receptor in atherogenesis - Decreased lesion formation in carotid artery ligation model in TR3 transgenic mice

Back-ground-Smooth muscle cells (SMCs) play a key role in intimal thickening in atherosclerosis and restenosis. The precise signaling pathways by which the proliferation of SMCs is regulated are largely unknown. The TR3 orphan receptor, the mitogen-induced nuclear orphan receptor (MINOR), and the nuclear receptor of T cells (NOT) are a subfamily of transcription factors belonging to the nuclear receptor superfamily and are induced in activated SMCS. In this study, we investigated the role of these transcription factors in SMC proliferation in atherogenesis. Methods and Results-Multiple human vascular specimens at distinct stages of atherosclerosis (lesion types II to V by American Heart Association classification) derived from 14 different individuals were studied for expression of these transcription factors. We observed expression of TR3, MINOR, and NOT in neointimal SMCs, whereas no expression was detected in medial SMCs. Adenovirus-mediated expression of a dominant-negative variant of TR3, which suppresses die transcriptional activity of each subfamily member, increases DNA synthesis and decreases p27(Kip1) protein expression in cultured SMCs. We generated transgenic mice that express this dominant-negative variant or full-length TR3 under control of a vascular SMC-specific promoter. Carotid artery ligation of transgenic mice that express the dominant-negative variant of TR3 in arterial SMCs, compared with lesions formed in wild-type mice, results in a 3-fold increase in neointimal formation, whereas neointimal formation is inhibited 5-fold in transgenic mice expressing full-length TR3. Conclusions-Our results reveal that TR3 and possibly other members of this transcription factor subfamily inhibit vascular lesion formation. These transcription factors could serve as novel targets in the treatment of vascular diseas

TR3 Nuclear Orphan Receptor Prevents Cyclic Stretch-Induced Proliferation of Venous Smooth Muscle Cells

In coronary artery bypass surgery, the patency of arterial grafts is higher than that of venous grafts because of vein-graft disease, which involves excessive proliferation of venous smooth muscle cells (SMCs) and subsequent accelerated atherosclerosis. We studied the function of TR3 nuclear orphan receptor (TR3) in the early response of SMCs to mechanical strain, a major initiator of vein-graft disease. We demonstrate that TR3 expression is induced in human saphenous vein segments exposed ex vivo to whole-blood perfusion under arterial pressure. Cultured venous SMCs challenged by cyclic stretch displayed TR3 induction and enhanced DNA synthesis, whereas SMCs derived from the internal mammary artery remained quiescent. Small-interfering RNA-mediated knockdown of TR3 and adenovirus-mediated overexpression of TR3 in venous SMCs enhanced and abolished stretch-induced DNA synthesis, respectively. Accordingly, in organ cultures of wild-type murine vessel segments exposed to cyclic stretch, p27(Kip1) was down-regulated, whereas expression of this cell cycle inhibitor was unaffected by cyclic stretch in TR3-transgenic vessels, concordant with a lower proliferative response. Finally, stretch-mediated proliferation was inhibited by 6-mercaptopurine, an agonist of TR3. In conclusion, TR3 represents inhibitory mechanisms to restrict venous SMC proliferation and may contribute to prevention of vein-graft disease

TR3 orphan receptor is expressed in vascular endothelial cells and mediates cell cycle arrest

Objective - Endothelial cells play a pivotal role in vascular homeostasis. In this study, we investigated the function of the nerve growth factor - induced protein-B (NGFI-B) subfamily of nuclear receptors comprising the TR3 orphan receptor (TR3), mitogen-induced nuclear orphan receptor (MINOR), and nuclear orphan receptor of T cells ( NOT) in endothelial cells. Methods and Results - The mRNA expression of TR3, MINOR, and NOT in atherosclerotic lesions was assessed in human vascular specimens. Each of these factors is expressed in smooth muscle cells, as described before, and in subsets of endothelial cells, implicating that they might affect endothelial cell function. Adenoviral overexpression of TR3 in cultured endothelial cells resulted in decreased [H-3] thymidine incorporation, whereas a dominant-negative TR3 variant that inhibits the activity of endogenous TR3-like factors enhanced DNA synthesis. TR3 interfered with progression of the cell cycle by upregulating p27(Kip1) and downregulating cyclin A, whereas expression levels of a number of other cell cycle - associated proteins remained unchanged. Conclusions - These findings demonstrate that TR3 is a modulator of endothelial cell proliferation and arrests endothelial cells in the G1 phase of the cell cycle by influencing cell cycle protein levels. We hypothesize involvement of TR3 in the maintenance of integrity of the vascular endotheliu