Abstract-Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), encoded by the OLR1 gene, is a scavenger receptor that plays a fundamental role in the pathogenesis of atherosclerosis. LOX-1 activation is associated with apoptosis of endothelial cells, smooth muscle cells (SMCs), and macrophages. This process is an important underlying mechanism that contributes to plaque instability and subsequent development of acute coronary syndromes. Independent association genetic studies have implicated OLR1 gene variants in myocardial infarction (MI) susceptibility. Because single nucleotide polymorphisms (SNPs) linked to MI are located in intronic sequences of the gene, it remains unclear as to how they determine their biological effects. Using quantitative real-time PCR and minigene approach, we show that intronic SNPs, linked to MI, regulate the expression of a new functional splicing isoform of the OLR1 gene, LOXIN, which lacks exon 5. Macrophages from subjects carrying the "non-risk" disease haplotype at OLR1 gene have an increased expression of LOXIN at mRNA and protein level, which results in a significant reduction of apoptosis in response to oxLDL. Expression of LOXIN in different cell types results in loss of surface staining, indicating that truncation of the C-terminal portion of the protein has a profound effect on its cellular trafficking. Furthermore, the proapoptotic effect of LOX-1 receptor in cell culture is specifically rescued by the coexpression of LOXIN in a dose-dependent manner. The demonstration that increasing levels of LOXIN protect cells from LOX-1 induced apoptosis sets a groundwork for developing therapeutic approaches for prevention of plaque instability.
Women are referred for AF ablation later with a more complex clinical pre-operative presentation. Despite this higher risk profile in women, no differences were detected in clinical outcomes. Our findings indicate that CA of AF appears to be safe and effective in women as in men.
Despite numerous possible risk factors, the most common and consistent predictors of stent thrombosis are early antiplatelet therapy discontinuation, extent of coronary disease, and stent number/length.
Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), the principal receptor for oxidized low-density lipoprotein (ox-LDL) in vascular endothelial cells (ECs), has recently been suggested to exert a pivotal role in atherogenesis, possibly by mediating ox-LDL-evoked endothelial dysfunction. On the other hand, LOX-1 expression seems to strongly correlate with the oxidative stress occurring in the vascular wall of experimentally injured blood vessels. Here, we investigated LOX-1 expression and superoxide generation during neointima formation in a balloon injury rat carotid artery model. To test this, we used M40401 [a manganese(II) complex with a bis(cyclo-hexylpyridine-substituted) macrocyclic ligand], a synthetic superoxide dismutase mimetic that is a selective scavenger of superoxide. The injury was performed inserting the balloon catheter through the rat common carotid artery and after 14 days a histopathological analysis revealed a significant restenosis with smooth muscle cell proliferation and neointima formation that was associated with an enhanced expression of LOX-1, nitrotyrosine (the footprint of peroxynitrite) staining, and lipid peroxidation as assessed by malondialdehyde (MDA) formation. Pretreatment of rats with M40401 (0.5-10 mg/kg i.p. daily) reduced neointima formation, MDA accumulation, nitrotyrosine staining, and LOX-1 expression. Here, we show that removal of superoxide formation occurring in injured arteries reduces both neointima formation and LOX-1 expression and that this may represent a novel therapeutical approach in the treatment of vascular disorders in which proliferation of vascular smooth muscle cells and ox-LDL-related endothelial cell dysfunction occur.
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