Neil3-dependent base excision repair regulates lipid metabolism and prevents atherosclerosis in Apoe-deficient mice

Increasing evidence suggests that oxidative DNA damage accumulates in atherosclerosis. Recently, we showed that a genetic variant in the human DNA repair enzyme NEIL3 was associated with increased risk of myocardial infarction. Here, we explored the role of Neil3/NEIL3 in atherogenesis by both clinical and experimental approaches. Human carotid plaques revealed increased NEIL3 mRNA expression which significantly correlated with mRNA levels of the macrophage marker CD68. Apoe−/−Neil3−/− mice on high-fat diet showed accelerated plaque formation as compared to Apoe−/− mice, reflecting an atherogenic lipid profile, increased hepatic triglyceride levels and attenuated macrophage cholesterol efflux capacity. Apoe−/−Neil3−/− mice showed marked alterations in several pathways affecting hepatic lipid metabolism, but no genotypic alterations in genome integrity or genome-wide accumulation of oxidative DNA damage. These results suggest a novel role for the DNA glycosylase Neil3 in atherogenesis in balancing lipid metabolism and macrophage function, potentially independently of genome-wide canonical base excision repair of oxidative DNA damage

Status Update and Interim Results from the Asymptomatic Carotid Surgery Trial-2 (ACST-2)

Objectives: ACST-2 is currently the largest trial ever conducted to compare carotid artery stenting (CAS) with carotid endarterectomy (CEA) in patients with severe asymptomatic carotid stenosis requiring revascularization. Methods: Patients are entered into ACST-2 when revascularization is felt to be clearly indicated, when CEA and CAS are both possible, but where there is substantial uncertainty as to which is most appropriate. Trial surgeons and interventionalists are expected to use their usual techniques and CE-approved devices. We report baseline characteristics and blinded combined interim results for 30-day mortality and major morbidity for 986 patients in the ongoing trial up to September 2012. Results: A total of 986 patients (687 men, 299 women), mean age 68.7 years (SD ± 8.1) were randomized equally to CEA or CAS. Most (96%) had ipsilateral stenosis of 70-99% (median 80%) with contralateral stenoses of 50-99% in 30% and contralateral occlusion in 8%. Patients were on appropriate medical treatment. For 691 patients undergoing intervention with at least 1-month follow-up and Rankin scoring at 6 months for any stroke, the overall serious cardiovascular event rate of periprocedural (within 30 days) disabling stroke, fatal myocardial infarction, and death at 30 days was 1.0%. Conclusions: Early ACST-2 results suggest contemporary carotid intervention for asymptomatic stenosis has a low risk of serious morbidity and mortality, on par with other recent trials. The trial continues to recruit, to monitor periprocedural events and all types of stroke, aiming to randomize up to 5,000 patients to determine any differential outcomes between interventions. Clinical trial: ISRCTN21144362. © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved

Second asymptomatic carotid surgery trial (ACST-2): a randomised comparison of carotid artery stenting versus carotid endarterectomy

Background: Among asymptomatic patients with severe carotid artery stenosis but no recent stroke or transient cerebral ischaemia, either carotid artery stenting (CAS) or carotid endarterectomy (CEA) can restore patency and reduce long-term stroke risks. However, from recent national registry data, each option causes about 1% procedural risk of disabling stroke or death. Comparison of their long-term protective effects requires large-scale randomised evidence. Methods: ACST-2 is an international multicentre randomised trial of CAS versus CEA among asymptomatic patients with severe stenosis thought to require intervention, interpreted with all other relevant trials. Patients were eligible if they had severe unilateral or bilateral carotid artery stenosis and both doctor and patient agreed that a carotid procedure should be undertaken, but they were substantially uncertain which one to choose. Patients were randomly allocated to CAS or CEA and followed up at 1 month and then annually, for a mean 5 years. Procedural events were those within 30 days of the intervention. Intention-to-treat analyses are provided. Analyses including procedural hazards use tabular methods. Analyses and meta-analyses of non-procedural strokes use Kaplan-Meier and log-rank methods. The trial is registered with the ISRCTN registry, ISRCTN21144362. Findings: Between Jan 15, 2008, and Dec 31, 2020, 3625 patients in 130 centres were randomly allocated, 1811 to CAS and 1814 to CEA, with good compliance, good medical therapy and a mean 5 years of follow-up. Overall, 1% had disabling stroke or death procedurally (15 allocated to CAS and 18 to CEA) and 2% had non-disabling procedural stroke (48 allocated to CAS and 29 to CEA). Kaplan-Meier estimates of 5-year non-procedural stroke were 2·5% in each group for fatal or disabling stroke, and 5·3% with CAS versus 4·5% with CEA for any stroke (rate ratio [RR] 1·16, 95% CI 0·86–1·57; p=0·33). Combining RRs for any non-procedural stroke in all CAS versus CEA trials, the RR was similar in symptomatic and asymptomatic patients (overall RR 1·11, 95% CI 0·91–1·32; p=0·21). Interpretation: Serious complications are similarly uncommon after competent CAS and CEA, and the long-term effects of these two carotid artery procedures on fatal or disabling stroke are comparable. Funding: UK Medical Research Council and Health Technology Assessment Programme

Clinical diagnosis of Larsen syndrome, Stickler syndrome and Loeys-Dietz syndrome in a 19-year old male: a case report

Background Larsen syndrome is a hereditary disorder characterized by osteochondrodysplasia, congenital large-joint dislocations, and craniofacial abnormalities. The autosomal dominant type is caused by mutations in the gene that encodes the connective tissue protein, filamin B (FLNB). Loeys-Dietz syndrome (LDS) is an autosomal dominant connective tissue disorder characterized by arterial aneurysms, dissections and tortuosity, and skeletal, including craniofacial, manifestations. Mutations in five genes involved in the transforming growth factor beta (TGF-β) signaling pathway cause five types of LDS. Stickler syndrome is a genetically heterogeneous arthro-ophthalmopathy caused by defects in collagen, exhibiting a wide specter of manifestations in connective tissue. A rare case is reported that was diagnosed with all these three hereditary connective tissue disorders. Case presentation A 19 year-old, Norwegian male with a clinical diagnosis of Larsen syndrome and with healthy, non-consanguineous parents attended a reference center for rare connective tissue disorders. Findings at birth were hypotonia, joint hypermobility, hyperextended knees, adductovarus of the feet, cervical kyphosis, craniofacial abnormalities, and an umbilical hernia. From toddlerhood, he required a hearing aid due to combined conductive and sensorineural hearing loss. Eye examination revealed hyperopia, astigmatism, and exotropia. At 10 years of age, he underwent emergency surgery for rupture of an ascending aortic aneurysm. At 19 years of age, a diagnostic re-evaluation was prompted by the findings of more distal aortic dilation, tortuosity of precerebral arteries, and skeletal findings. High throughput sequencing of 34 genes for hereditary connective tissue disorders did not identify any mutation in FLNB, but did identify a de novo missense mutation in TGFBR2 and a nonsense mutation in COL2A1 that was also present in his unaffected father. The diagnosis was revised to LDS Type 2. The patient also fulfills the proposed criteria for Stickler syndrome with bifid uvula, hearing loss, and a known mutation in COL2A1. Conclusion LDS should be considered in patients with a clinical diagnosis of Larsen syndrome, in particular in the presence of arterial aneurysms or tortuosity. Due to genetic heterogeneity and extensive overlap of clinical manifestations, genetic high throughput sequencing analysis is particularly useful for the differential diagnosis of hereditary connective tissue disorders

Increased levels of CCR7 ligands in carotid atherosclerosis: different effects in macrophages and smooth muscle cells

AIM: The homeostatic chemokines CCL19 and CCL21 and their receptor CCR7 have recently been linked to atherogenesis. We investigated the expression of CCL19/CCL21/CCR7 in carotid atherosclerosis as well as the ability of these chemokines to modulate lipid accumulation in macrophages and vascular smooth muscle cell (SMC) phenotype.Methods and ResultsOur major findings were: (i) Patients with carotid atherosclerosis (n=158) had increased plasma levels of CCL21, but not of CCL19, compared to controls (n=20), with particularly high levels in symptomatic (n=99) as compared with asymptomatic (n=59) disease. (ii) Carotid plaques showed markedly increased mRNA levels of CCL21 and CCL19 in symptomatic (n=14) as compared with asymptomatic (n=7) patients, with CCR7 localized to macrophages and vascular SMC (immunohistochemistry). (iii) In vitro, CCL21, but not CCL19, increased the binding of modified LDL and promoted lipid accumulation in THP-1 macrophages. (iv). CCL19, but not CCL21, increased proliferation and release and activity of matrix metalloproteinase (MMP) 1 in vascular SMC. (v). The differential effects of CCL19 and CCL21 in macrophages and SMC seem to be attributable to divergent signaling pathways, with CCL19-mediated activation of AKT in SMC and CCL21-mediated activation of extracellular signal-regulated kinase 1/2 in macrophages. CONCLUSION: CCL19 and CCL21 are up-regulated in carotid atherosclerosis. The ability of CCL21 to promote lipid accumulation in macrophages and of CCL19 to induce proliferation and MMP-1 expression in vascular SMC could contribute to their pro-atherogenic potential

Increased expression of NAMPT in PBMC from patients with acute coronary syndrome and in inflammatory M1 macrophages

AbstractAimThe aim of the present study were to elucidate the role of NAMPT in atherosclerosis, by examine NAMPT expression in peripheral blood mononuclear cells (PBMC) in patients with coronary artery disease (CAD) and healthy controls and by examining the regulation and effect of NAMPT on macrophage polarization, hypothesizing that it could influence the polarization to inflammatory and resolving macrophages.Method and ResultsWe analyzed RNA levels of NAMPT in PBMC from CAD and healthy controls and found NAMPT to be increased in PBMC from patients with acute coronary syndrome (n = 39) compared to healthy controls (n = 20) and patients with stable CAD (n = 22). Within the PBMC NAMPT was correlated to several inflammatory cytokines and the antioxidant enzyme superoxide dismutase 2. In vitro cell experiments revealed that NAMPT is increased both intracellular and extracellular in inflammatory M1 macrophages compared to in anti-inflammatory M2 macrophages. In addition, inhibiting NAMPT enzymatic activity inhibited M1 polarization in macrophages.ConclusionBased on our in vivo and in vitro findings we suggest that NAMPT could contribute to systemic and plaque inflammation in atherosclerotic disorders at least partly through effect on macrophages