Atherosclerosis is a chronic inflammatory disease promoted by hyperlipidemia. Several studies support FOXP3-positive regulatory T cells (Tregs) as inhibitors of atherosclerosis; however, the mechanism underlying this protection remains elusive. To define the role of FOXP3-expressing Tregs in atherosclerosis, we used the DEREG mouse, which expresses the diphtheria toxin (DT) receptor under control of the Treg-specific Foxp3 promoter, allowing for specific ablation of FOXP3+ Tregs. Lethally irradiated, atherosclerosis-prone, low-density lipoprotein receptor–deficient (Ldlr–/–) mice received DEREG bone marrow and were injected with DT to eliminate FOXP3+ Tregs. Depletion of Tregs caused a 2.1-fold increase in atherosclerosis without a concomitant increase in vascular inflammation. These mice also exhibited a 1.7-fold increase in plasma cholesterol and an atherogenic lipoprotein profile with increased levels of VLDL. Clearance of VLDL and chylomicron remnants was hampered, leading to accumulation of cholesterol-rich particles in the circulation. Functional and protein analyses complemented by gene expression array identified reduced protein expression of sortilin-1 in liver and increased plasma enzyme activity of lipoprotein lipase, hepatic lipase, and phospholipid transfer protein as mediators of the altered lipid phenotype. These results demonstrate that FOXP3+ Tregs inhibit atherosclerosis by modulating lipoprotein metabolism.
Background. Falls and fractures in the elderly are among the leading causes of disability. We investigated whether pacemaker implantation prevents falls in patients with SND in a large cohort of patients. Methods. Patient demographics and medical history were collected prospectively. Fall history was retrospectively reconstituted from available medical records. The 10-year probability for major osteoporotic fractures was calculated retrospectively from available medical records using the Swiss fracture risk assessment tool FRAX-Switzerland. Results. During a mean observation period of 2.3 years after implantation, the rates of fallers and injured fallers with fracture were reduced to 15% and 6%, respectively. This corresponds to a relative reduction in the number of fallers of 75% (P < 0.001) and of injured fallers of 63% (P = 0.014) after pacemaker implantation. Similarly, the number of falls was reduced from 60 (48%) before pacemaker implantation to 22 (18%) thereafter (relative reduction 63%, P = 0.035) and the number of falls with injury from 22 (18%) to 7 (6%), which corresponds to a relative reduction of 67%, P = 0.013. Conclusion. In patients with SND, pacemaker implantation significantly reduces the number of patients experiencing falls, the total number of falls, and the risk for osteoporotic fractures.
Through a 4-year follow-up of the abstracts submitted to the European Society of
Cardiology Congress in 2006, we aimed at identifying factors predicting high-quality
research, appraising the quality of the peer review and editorial processes, and thereby
revealing potential ways to improve future research, peer review, and editorial
Methods and results
All abstracts submitted in 2006 were assessed for acceptance, presentation format, and
average reviewer rating. Accepted and rejected studies were followed for 4 years.
Multivariate regression analyses of a representative selection of 10% of all
abstracts (n= 1002) were performed to identify factors
predicting acceptance, subsequent publication, and citation. A total of 10 020 abstracts
were submitted, 3104 (31%) were accepted for poster, and 701 (7%) for oral
presentation. At Congress level, basic research, a patient number ≥ 100, and
prospective study design were identified as independent predictors of acceptance. These
factors differed from those predicting full-text publication, which included academic
affiliation. The single parameter predicting frequent citation was study design with
randomized controlled trials reaching the highest citation rates. The publication rate
of accepted studies was 38%, whereas only 24% of rejected studies were
published. Among published studies, those accepted at the Congress received higher
citation rates than rejected ones.
Research of high quality was determined by study design and largely identified at
Congress level through blinded peer review. The scientometric follow-up revealed a
marked disparity between predictors of full-text publication and those predicting
citation or acceptance at the Congress.
Scientific quality; Peer review; Publication; Impact
Short QT syndrome (SQTS) is a genetically determined ion-channel disorder, which may cause malignant tachyarrhythmias and sudden cardiac death. Thus far, mutations in five different genes encoding potassium and calcium channel subunits have been reported. We present, for the first time, a novel loss-of-function mutation coding for an L-type calcium channel subunit.
Methods and results
The electrocardiogram of the affected member of a single family revealed a QT interval of 317 ms (QTc 329 ms) with tall, narrow, and symmetrical T-waves. Invasive electrophysiological testing showed short ventricular refractory periods and increased vulnerability to induce ventricular fibrillation. DNA screening of the patient identified no mutation in previously known SQTS genes; however, a new variant at a heterozygous state was identified in the CACNA2D1 gene (nucleotide c.2264G > C; amino acid p.Ser755Thr), coding for the Cavα2δ-1 subunit of the L-type calcium channel. The pathogenic role of the p.Ser755Thr variant of the CACNA2D1 gene was analysed by using co-expression of the two other L-type calcium channel subunits, Cav1.2α1 and Cavβ2b, in HEK-293 cells. Barium currents (IBa) were recorded in these cells under voltage-clamp conditions using the whole-cell configuration. Co-expression of the p.Ser755Thr Cavα2δ-1 subunit strongly reduced the IBa by more than 70% when compared with the co-expression of the wild-type (WT) variant. Protein expression of the three subunits was verified by performing western blots of total lysates and cell membrane fractions of HEK-293 cells. The p.Ser755Thr variant of the Cavα2δ-1 subunit was expressed at a similar level compared with the WT subunit in both fractions. Since the mutant Cavα2δ-1 subunit did not modify the expression of the pore-forming subunit of the L-type calcium channel, Cav1.2α1, it suggests that single channel biophysical properties of the L-type channel are altered by this variant.
In the present study, we report the first pathogenic mutation in the CACNA2D1 gene in humans, which causes a new variant of SQTS. It remains to be determined whether mutations in this gene lead to other manifestations of the J-wave syndrome.
Arrhythmia; Short QT syndrome; Novel gene mutation; Sudden cardiac death
Percutaneous carotid artery stenting (CAS) became a widely used procedure in patients with symptomatic and asymptomatic carotid artery stenosis. However its role compared to carotid endarterectomy (CAD) remains questioned. We analysed the safety of carotid artery stenting program of a prospective CAS register program of a tertiary teaching hospital.
Between July 2003 and December 2010, 208 patients underwent CAS procedure. Baseline, procedural and follow-up data were prospectively collected. Primary peri-interventional outcome was defined as 30-day major adverse events (MAE), including death, stroke or myocardial infarction, and mid- to long-term follow-up outcome included ipsilateral stroke, myocardial infarction or death. Secondary outcome was restenosis rate ≥50% per lesion.
Unilateral carotid artery interventions were performed in 186 patients. In 22 patients CAS was performed bilaterally as stages procedures. The 30-day MAE rate was 1.9% consisting of two contralateral strokes and two ipsilateral stroke. Mean clinically follow-up was 22 months. Mid- to long-term MAE was 8.1% with 6.3% (n = 13) deaths, 1.9% (n = 4) myocardial infarctions and 0.9% (n = 2) ipsilateral stroke. The restenosis rate ≥50% per lesion was 4.3% at a mean follow-up of 22 months. Target lesion revascularization was performed in one patient, because of restenosis at 9 months follow-up after first CAS.
Implementation of a carotid artery stenting program at a tertiary, teaching hospital is a safe method for treatment of carotid artery stenosis. The adverse event rate during mid-to-long-term follow-up suggests an appropriate patient selection.
Low high-density lipoprotein (HDL)-cholesterol levels are associated with an increased risk of coronary artery disease (CAD) and myocardial infarction, which has triggered the hypothesis that HDL, in contrast to low-density lipoprotein (LDL), acts as an anti-atherogenic lipoprotein. Moreover, experimental studies have identified potential anti-atherogenic properties of HDL, including promotion of macrophage cholesterol efflux and direct endothelial-protective effects of HDL, such as stimulation of endothelial nitric oxide production and repair, anti-apoptotic, anti-inflammatory and anti-thrombotic properties. Studies in gene-targeted mice, however, have also indicated that increasing HDL-cholesterol plasma levels can either limit (e.g. apolipoprotein A-I) or accelerate (e.g. Scavenger receptor class B type I) atherosclerosis. Moreover, vascular effects of HDL have been observed to be heterogenous and are altered in patients with CAD or diabetes, a condition that has been termed ‘HDL dysfunction’. These alterations in biological functions of HDL may need to be taken into account for HDL-targeted therapies and considering raising of HDL-cholesterol levels alone is likely not sufficient in this respect. It will therefore be important to further determine, which biological functions of HDL are critical for its anti-atherosclerotic properties, as well as how these can be measured and targeted.
coronary artery disease; endothelium; high-density lipoprotein; inflammation; nitric oxide
Patients with chronic heart failure (CHF) show impaired health-related quality of life
(HRQoL), an important target for therapeutic intervention. Impaired iron homeostasis may
be one mechanism underlying the poor physical condition of CHF patients. This detailed
subanalysis of the previously published FAIR-HF study evaluated baseline HRQoL in
iron-deficient patients with CHF and the effect of intravenous ferric carboxymaltose
(FCM) on HRQoL.
Methods and results
FAIR-HF randomized 459 patients with reduced left ventricular ejection fraction and
iron deficiency, with or without anaemia, to FCM or placebo (2:1). Health-related
quality of life was assessed at baseline and after 4, 12, and 24 weeks of therapy using
the generic EQ-5D questionnaire and disease-specific Kansas City Cardiomyopathy
Questionnaire (KCCQ). Baseline mean Visual Analogue Scale (VAS) score was 54.3 ±
16.4 and KCCQ overall summary score was 52.4 ± 18.8. Ferric carboxymaltose
significantly improved VAS and KCCQ (mean differences from baseline in KCCQ overall,
clinical and total symptom scores, P< 0.001 vs. placebo) at all
time points. At Week 24, significant improvement vs. placebo was observed in four of the
five EQ-5D dimensions: mobility (P= 0.004), self-care
(P< 0.001), pain/discomfort (P=
0.006), anxiety/depression (P= 0.012), and usual activity
(P= 0.035). Ferric carboxymaltose improved all KCCQ domain
mean scores from Week 4 onward (P≤ 0.05), except for
self-efficacy and social limitation. Effects were present in both anaemic and
HRQoL is impaired in iron-deficient patients with CHF. Intravenous FCM significantly
improved HRQoL after 4 weeks, and throughout the remaining study period. The positive
effects of FCM were independent of anaemia status.
Anaemia; Chronic heart failure; Health-related quality of life; Iron deficiency
In idiopathic pulmonary fibrosis loss of alveolar epithelium induces inflammation of the pulmonary tissue followed by accumulation of pathogenic myofibroblasts leading eventually to respiratory failures. In animal models inflammatory and resident cells have been demonstrated to contribute to pulmonary fibrosis. Regenerative potential of pulmonary and extra-pulmonary stem and progenitor cells raised the hope for successful treatment option against pulmonary fibrosis. Herein, we addressed the contribution of lung microenvironment and prominin-1+ bone marrow-derived epithelial progenitor cells in the mouse model of bleomycin-induced experimental pulmonary fibrosis.
Prominin-1+ bone marrow-derived epithelial progenitors were expanded from adult mouse lungs and differentiated in vitro by cytokines and growth factors. Pulmonary fibrosis was induced in C57Bl/6 mice by intratracheal instillation of bleomycin. Prominin-1+ progenitors were administered intratracheally at different time points after bleomycin challenge. Green fluorescence protein-expressing cells were used for cell tracking. Cell phenotypes were characterized by immunohistochemistry, flow cytometry and quantitative reverse transcription-polymerase chain reaction.
Prominin-1+ cells expanded from healthy lung represent common progenitors of alveolar type II epithelial cells, myofibroblasts, and macrophages. Administration of prominin-1+ cells 2 hours after bleomycin instillation protects from pulmonary fibrosis, and some of progenitors differentiate into alveolar type II epithelial cells. In contrast, prominin-1+ cells administered at day 7 or 14 lose their protective effects and differentiate into myofibroblasts and macrophages. Bleomycin challenge enhances accumulation of bone marrow-derived prominin-1+ cells within inflamed lung. In contrast to prominin-1+ cells from healthy lung, prominin-1+ precursors isolated from inflamed organ lack regenerative properties but acquire myofibroblast and macrophage phenotypes.
The microenvironment of inflamed lung impairs the regenerative capacity of bone marrow-derived prominin-1+ progenitors and promotes their differentiation into pathogenic phenotypes.
bone marrow; idiopathic pulmonary fibrosis; lung; myofibroblasts; progenitor; prominin-1/CD133
Cardiac hybrid imaging by fusing single-photon emission computed tomography (SPECT) myocardial perfusion imaging with coronary computed tomography angiography (CCTA) provides important complementary diagnostic information for coronary artery disease (CAD) assessment. We aimed at assessing the impact of cardiac hybrid imaging on the choice of treatment strategy selection for CAD.
Methods and results
Three hundred and eighteen consecutive patients underwent a 1 day stress/rest 99mTc-tetrofosmin SPECT and a CCTA on a separate scanner for evaluation of CAD. Patients were divided into one of the following three groups according to findings in the hybrid images obtained by fusing SPECT and CCTA: (i) matched finding of stenosis by CCTA and corresponding reversible SPECT defect; (ii) unmatched CCTA and SPECT finding; (iii) normal finding by both CCTA and SPECT. Follow-up was confined to the first 60 days after hybrid imaging as this allows best to assess treatment strategy decisions including the revascularization procedure triggered by its findings. Hybrid images revealed matched, unmatched, and normal findings in 51, 74, and 193 patients. The revascularization rate within 60 days was 41, 11, and 0% for matched, unmatched, and normal findings, respectively (P< 0.001 for all inter-group comparisons).
Cardiac hybrid imaging with SPECT and CCTA provides an added clinical value for decision making with regard to treatment strategy for CAD.
Coronary artery disease; SPECT/CT fusion imaging; Coronary CT angiography; Myocardial perfusion imaging; Treatment strategy; Clinical decision making
Atherosclerosis is an inflammatory disease characterized by accumulation of leukocytes in the arterial intima. Members of the selectin family of adhesion molecules are important mediators of leukocyte extravasation. However, it is unclear whether L-selectin (L-sel) is involved in the pathogenesis of atherosclerosis. In the present study, mice deficient in L-selectin (L-sel−/−) animals were crossed with mice lacking Apolipoprotein E (ApoE−/−). The development of atherosclerosis was analyzed in double-knockout ApoE/L-sel (ApoE−/− L-sel−/−) mice and the corresponding ApoE−/− controls fed either a normal or a high cholesterol diet (HCD). After 6 weeks of HCD, aortic lesions were increased two-fold in ApoE−/− L-sel−/− mice as compared to ApoE−/− controls (2.46%±0.54% vs 1.28%±0.24% of total aortic area; p<0.05). Formation of atherosclerotic lesions was also enhanced in 6-month-old ApoE−/− L-sel−/− animals fed a normal diet (10.45%±2.58% vs 1.87%±0.37%; p<0.05). In contrast, after 12 weeks of HCD, there was no difference in atheroma formation between ApoE−/− L-sel−/− and ApoE−/− mice. Serum cholesterol levels remained unchanged by L-sel deletion. Atherosclerotic plaques did not exhibit any differences in cellular composition assessed by immunohistochemistry for CD68, CD3, CD4, and CD8 in ApoE−/− L-sel−/− as compared to ApoE−/− mice. Leukocyte rolling on lesions in the aorta was similar in ApoE−/− L-sel−/− and ApoE−/− animals. ApoE−/− L-sel−/− mice exhibited reduced size and cellularity of peripheral lymph nodes, increased size of spleen, and increased number of peripheral lymphocytes as compared to ApoE−/− controls. These data indicate that L-sel does not promote atherosclerotic lesion formation and suggest that it rather protects from early atherosclerosis.
Evidence of the clinical benefit of 3-in-1 point-of-care testing (POCT) for cardiac troponin T (cTnT), N-terminal pro-brain natriuretic peptide (NT-proBNP) and D-dimer in cardiovascular risk stratification at primary care level for diagnosing acute coronary syndromes (ACS), heart failure (HF) and thromboembolic events (TE) is very limited. The aim of this study is to analyse the diagnostic accuracy of POCT in primary care.
Prospective multicentre controlled trial cluster-randomised to POCT-assisted diagnosis and conventional diagnosis (controls). Men and women presenting in 68 primary care practices in Zurich County (Switzerland) with chest pain or symptoms of dyspnoea or TE were consecutively included after baseline consultation and working diagnosis. A follow-up visit including confirmed diagnosis was performed to determine the accuracy of the working diagnosis, and comparison of working diagnosis accuracy between the two groups.
The 218 POCT patients and 151 conventional diagnosis controls were mostly similar in characteristics, symptoms and pre-existing diagnoses, but differed in working diagnosis frequencies. However, the follow-up visit showed no statistical intergroup difference in confirmed diagnosis frequencies. Working diagnoses overall were significantly more correct in the POCT group (75.7% vs 59.6%, p = 0.002), as were the working diagnoses of ACS/HF/TE (69.8% vs 45.2%, p = 0.002). All three biomarker tests showed good sensitivity and specificity.
POCT confers substantial benefit in primary care by correctly diagnosing significantly more patients.
Collagen degradation in atherosclerotic plaques with thin fibrous caps renders them more prone to rupture. Fibroblast activation protein (FAP) plays a role in arthritis and tumour formation through its collagenase activity. However, the significance of FAP in thin-cap human fibroatheromata remains unknown.
Methods and results
We detected enhanced FAP expression in type IV–V human aortic atheromata (n = 12), compared with type II–III lesions (n = 9; P < 0.01) and healthy aortae (n = 8; P < 0.01) by immunostaining and western blot analyses. Fibroblast activation protein was also increased in thin-cap (<65 µm) vs. thick-cap (≥65 µm) human coronary fibroatheromata (n = 12; P < 0.01). Fibroblast activation protein was expressed by human aortic smooth muscle cells (HASMC) as shown by colocalization on immunofluorescent aortic plaque stainings (n = 10; P < 0.01) and by flow cytometry in cell culture. Although macrophages did not express FAP, macrophage burden in human aortic plaques correlated with FAP expression (n = 12; R2= 0.763; P < 0.05). Enzyme-linked immunosorbent assays showed a time- and dose-dependent up-regulation of FAP in response to human tumour necrosis factor α (TNFα) in HASMC (n = 6; P < 0.01). Moreover, supernatants from peripheral blood-derived macrophages induced FAP expression in cultured HASMC (n = 6; P < 0.01), an effect abolished by blocking TNFα (n = 6; P < 0.01). Fibroblast activation protein associated with collagen-poor regions in human coronary fibrous caps and digested type I collagen and gelatin in vitro (n = 6; P < 0.01). Zymography revealed that FAP-mediated collagenase activity was neutralized by an antibody directed against the FAP catalytic domain both in HASMC (n = 6; P < 0.01) and in fibrous caps of atherosclerotic plaques (n = 10; P < 0.01).
Fibroblast activation protein expression in HASMC is induced by macrophage-derived TNFα. Fibroblast activation protein associates with thin-cap human coronary fibroatheromata and contributes to type I collagen breakdown in fibrous caps.
Atherosclerosis; Antibodies; Collagen; Inflammation; Smooth muscle cells
Epidemiological studies report an inverse association between plant-derived dietary α-linolenic acid (ALA) and cardiovascular events. However, little is known about the mechanism of this protection. We assessed the cellular and molecular mechanisms of dietary ALA (flaxseed) on atherosclerosis in a mouse model.
Methods and results
Eight-week-old male apolipoprotein E knockout (ApoE−/−) mice were fed a 0.21 % (w/w) cholesterol diet for 16 weeks containing either a high ALA [7.3 % (w/w); n = 10] or low ALA content [0.03 % (w/w); n = 10]. Bioavailability, chain elongation, and fatty acid metabolism were measured by gas chromatography of tissue lysates and urine. Plaques were assessed using immunohistochemistry. T cell proliferation was investigated in primary murine CD3-positive lymphocytes. T cell differentiation and activation was assessed by expression analyses of interferon-γ, interleukin-4, and tumour necrosis factor α (TNFα) using quantitative PCR and ELISA. Dietary ALA increased aortic tissue levels of ALA as well as of the n−3 long chain fatty acids (LC n−3 FA) eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid. The high ALA diet reduced plaque area by 50% and decreased plaque T cell content as well as expression of vascular cell adhesion molecule-1 and TNFα. Both dietary ALA and direct ALA exposure restricted T cell proliferation, differentiation, and inflammatory activity. Dietary ALA shifted prostaglandin and isoprostane formation towards 3-series compounds, potentially contributing to the atheroprotective effects of ALA.
Dietary ALA diminishes experimental atherogenesis and restricts T cell-driven inflammation, thus providing the proof-of-principle that plant-derived ALA may provide a valuable alternative to marine LC n−3 FA.
α-Linolenic acid; Atherosclerosis; Inflammation; Polyunsaturated fatty acids
Introduction. For pulmonary vein isolation in patients with atrial fibrillation (AF), some centers use the double transseptal puncture technique for catheter access in order to facilitate catheter manipulation within the left atrium. However, no safety data has so far been published using this approach.
Method. 269 ablation procedures were performed in 243 patients (mean age 56.6 ± 9.3 years, 75% men) using the double transseptal puncture for catheter access in all cases. Patients were considered for ablation of paroxysmal (80%), persistent (19%), and permanent (1%) AF. 230 procedures were performed on an outpatient basis (85.5%), and 26 were repeat procedures (9.7%).
Results. The double transseptal puncture catheter access was successfully achieved in all patients. The procedural success with the endpoint of pulmonary vein isolation was reached in 255 procedures (95%). A total of 1048 out of 1062 pulmonary veins (99%) were successfully isolated. Major complications occurred in eight patients (3.0%). Of these, seven patients (2.6%) had pericardial effusion requiring percutaneous drainage, and one patient (0.4%) suffered a minor reversible stroke. One patient (0.4%) had a minor air embolism with transient symptoms.
Conclusion. The double transseptal puncture catheterization technique allows easy catheter manipulation within the left atrium to reach the goal of acute procedural success in AF ablation. Procedure-related complications are rare, and the technique can be used safely for AF ablation in the outpatient setting.
Atherosclerosis is a chronic inflammatory disease that evolves from the interaction of activated endothelial cells, macrophages, lymphocytes and modified lipoproteins (LDLs). In the last years many molecules with crucial metabolic functions have been shown to prevent important steps in the progression of atherogenesis, including peroxisome proliferator activated receptors (PPARs) and the class III histone deacetylase (HDAC) SIRT1. The PPARγ coactivator 1 alpha (Ppargc1a or PGC-1α) was identified as an important transcriptional cofactor of PPARγ and is activated by SIRT1. The aim of this study was to analyze total PGC-1α deficiency in an atherosclerotic mouse model.
To investigate if total PGC-1α deficiency affects atherosclerosis, we compared ApoE−/− PGC-1α−/− and ApoE−/− PGC-1α+/+ mice kept on a high cholesterol diet. Despite having more macrophages and a higher ICAM-1 expression in plaques, ApoE−/− PGC-1α−/− did not display more or larger atherosclerotic plaques than their ApoE−/− PGC-1α+/+ littermates. In line with the previously published phenotype of PGC-1α−/− mice, ApoE−/− PGC-1α−/− mice had marked reduced body, liver and epididymal white adipose tissue (WAT) weight. VLDL/LDL-cholesterol and triglyceride contents were also reduced. Aortic expression of PPARα and PPARγ, two crucial regulators for adipocyte differentitation and glucose and lipid metabolism, as well as the expression of some PPAR target genes was significantly reduced in ApoE−/− PGC-1α−/− mice. Importantly, the epididymal WAT and aortic expression of IL-18 and IL-18 plasma levels, a pro-atherosclerotic cytokine, was markedly reduced in ApoE−/− PGC-1α−/− mice.
ApoE−/− PGC-1α−/− mice, similar as PGC-1α−/− mice exhibit markedly reduced total body and visceral fat weight. Since inflammation of visceral fat is a crucial trigger of atherogenesis, decreased visceral fat in PGC-1α-deficient mice may explain why these mice do not develop enhanced atherosclerosis.
We have repeatedly detected Candidatus Neoehrlichia mikurensis, a bacterium first described in Rattus norvegicus rats and Ixodes ovatus ticks in Japan in 2004 in the blood of a 61-year-old man with signs of septicemia by 16S rRNA and groEL gene PCR. After 6 weeks of therapy with doxycycline and rifampin, the patient recovered.
Candidatus Neoehrlichia mikurensis; septicemia; human infection; 16S rRNA gene PCR; therapy; tick-borne pathogen; bacteria; dispatch
Coronary late stent thrombosis, a rare but devastating complication, remains an important concern in particular with the increasing use of drug-eluting stents. Notably, pathological studies have indicated that the proportion of uncovered coronary stent struts represents the best morphometric predictor of late stent thrombosis. Intracoronary optical frequency domain imaging (OFDI), a novel second-generation optical coherence tomography (OCT)-derived imaging method, may allow rapid imaging for the detection of coronary stent strut coverage with a markedly higher precision when compared with intravascular ultrasound, due to a microscopic resolution (axial ∼10–20 µm), and at a substantially increased speed of image acquisition when compared with first-generation time-domain OCT. However, a histological validation of coronary OFDI for the evaluation of stent strut coverage in vivo is urgently needed. Hence, the present study was designed to evaluate the capacity of coronary OFDI by electron (SEM) and light microscopy (LM) analysis to detect and evaluate stent strut coverage in a porcine model.
Methods and results
Twenty stents were implanted into 10 pigs and coronary OFDI was performed after 1, 3, 10, 14, and 28 days. Neointimal thickness as detected by OFDI correlated closely with neointimal thickness as measured by LM (r = 0.90, P < 0.01). The comparison of stent strut coverage as detected by OFDI and SEM analysis revealed an excellent agreement (r = 0.96, P < 0.01). In particular, stents completely covered by OFDI analysis were also completely covered by SEM analysis. All incompletely covered stents by OFDI were also incompletely covered by SEM. Analyses of fibrin-covered stent struts suggested that these may rarely be detected as uncovered stent struts by OFDI. Importantly, optical density measurements revealed a significant difference between fibrin- and neointima-covered coronary stent struts [0.395 (0.35–0.43) vs. 0.53 (0.47–0.57); P < 0.001], suggesting that differences in optical density provide information on the type of stent strut coverage. The sensitivity and specificity for detection of fibrin vs. neointimal coverage was evaluated using receiver-operating characteristic analysis.
The present study demonstrates that OFDI is a highly promising tool for accurate evaluation of coronary stent strut coverage, as supported by a high agreement between OFDI and light and electron microscopic analysis. Furthermore, our data indicate that optical density measurements can provide additional information with respect to the type of stent strut coverage, i.e. fibrin vs. neointimal coverage. Therefore, coronary OFDI analysis will provide important information on the biocompatibility of coronary stents.
Optical frequency domain imaging; Stent strut coverage; Histological validation
production of reactive oxygen species (ROS) contributes to progression of
atherosclerosis, at least in part by causing endothelial dysfunction and
inflammatory activation. The class III histone deacetylase SIRT1 has been
implicated in extension of lifespan. In the vasculature,SIRT1
gain-of-function using SIRT1 overexpression or activation has been
shown to improve endothelial function in mice and rats via stimulation of
endothelial nitric oxide (NO) synthase (eNOS). However, the effects of SIRT1
loss-of-function on the endothelium in atherosclerosis remain to be
characterized. Thus, we have investigated the endothelial effects of
decreased endogenous SIRT1 in hypercholesterolemic ApoE-/-
mice. We observed no difference in endothelial relaxation and eNOS (Ser1177)
phosphorylation between 20-week old male atherosclerotic ApoE-/-
SIRT1+/- and ApoE-/- SIRT1+/+ mice.
However, SIRT1 prevented endothelial superoxide production, inhibited
NF-κB signaling, and diminished expression of adhesion molecules.
Treatment of young hypercholesterolemic ApoE-/- SIRT1+/-
mice with lipopolysaccharide to boost NF-κB signaling led to a more
pronounced endothelial expression of ICAM-1 and VCAM-1 as compared to ApoE-/-
SIRT1+/+ mice. In conclusion, endogenous SIRT1 diminishes
endothelial activation in ApoE-/- mice, but does not
affect endothelium-dependent vasodilatation.
SIRT1; atherosclerosis; endothelium; inflammation
Endothelial activation, macrophage infiltration, and foam cell formation are pivotal steps in atherogenesis. Our aim in this study was to analyse the role of SIRT1, a class III deacetylase with important metabolic functions, in plaque macrophages and atherogenesis.
Methods and results
Using partial SIRT1 deletion in atherosclerotic mice, we demonstrate that SIRT1 protects against atherosclerosis by reducing macrophage foam cell formation. Peritoneal macrophages from heterozygous SIRT1 mice accumulate more oxidized low-density lipoprotein (oxLDL), thereby promoting foam cell formation. Bone marrow-restricted SIRT1 deletion confirmed that SIRT1 function in macrophages is sufficient to decrease atherogenesis. Moreover, we show that SIRT1 reduces the uptake of oxLDL by diminishing the expression of lectin-like oxLDL receptor-1 (Lox-1) via suppression of the NF-κB signalling pathway.
Our findings demonstrate protective effects of SIRT1 in atherogenesis and suggest pharmacological SIRT1 activation as a novel anti-atherosclerotic strategy by reducing macrophage foam cell formation.
SIRT1; Macrophage foam cell; Atherogenesis
Iron deficiency (ID) and anaemia are common in patients with chronic heart failure (CHF). The presence of anaemia is associated with increased morbidity and mortality in CHF, and ID is a major reason for the development of anaemia. Preliminary studies using intravenous (i.v.) iron supplementation alone in patients with CHF and ID have shown improvements in symptom status. FAIR-HF (Clinical Trials.gov NCT00520780) was designed to determine the effect of i.v. iron repletion therapy using ferric carboxymaltose on self-reported patient global assessment (PGA) and New York Heart Association (NYHA) in patients with CHF and ID.
Methods and results
This is a multi-centre, randomized, double-blind, placebo-controlled study recruiting ambulatory patients with symptomatic CHF with LVEF ≤ 40% (NYHA II) or ≤45% (NYHA III), ID [ferritin <100 ng/mL or ferritin 100–300 ng/mL when transferrin saturation (TSAT) < 20%], and haemoglobin 9.5–13.5 g/dL. Patients were randomized in a 2:1 ratio to receive ferric carboxymaltose (Ferinject®) 200 mg iron i.v. or saline i.v. weekly until iron repletion (correction phase), then monthly until Week 24 (maintenance phase). Primary endpoints are (i) self-reported PGA at Week 24 and (ii) NYHA class at Week 24, adjusted for baseline NYHA class.
This study will provide evidence on the efficacy and safety of iron repletion with ferric carboxymaltose in CHF patients with ID with and without anaemia.
Chronic heart failure; Iron deficiency; Anaemia; Treatment; Ferric carboxymaltose
Inflammation plays a key role in atherosclerosis. Sirt1 regulates transcription factors involved in inflammatory processes and blunts atherosclerosis in mice. However, its role in humans remains to be defined. This study was therefore designed to investigate the role of Sirt1 in the development of atherosclerosis.
Methods and Results
48 male subjects admitted for cardiac catheterization were subdivided into healthy subjects, patients with stable coronary artery disease (CAD), and with acute coronary syndromes (ACS). Monocytes were isolated and Sirt1 mRNA levels were determined. Sirt1 gene expression was higher in healthy subjects as compared to patients with CAD or ACS (P<0.05), respectively. Interestingly, HDL levels correlated positively with Sirt1 expression. Thus, HDL from the three groups was isolated and incubated with THP-1 monocytes to determine the effects of HDL on Sirt1 protein in controlled experimental conditions. HDL from healthy subjects stimulated Sirt1 expression in THP-1 monocytes to a higher degree than HDL from CAD and ACS patients (P<0.05). Paraoxonase-1 (PON-1), a HDL-associated enzyme, showed a reduced activity in HDL isolated from CAD and ACS patients as compared to the controls (P<0.001).
Monocytic Sirt1 expression is reduced in patients with stable CAD and ACS. Experiments on THP-1 monocytes suggest that this effect is HDL-dependent and is mediated by a reduced activity of HDL-associated enzyme PON1.
Adeno-associated viruses (AAVs) are promising vectors for various gene therapy applications due to their long-lasting transgene expression and wide spectrum of target cells. Recently, however, it has become apparent that there are considerable differences in the efficiencies of transduction of different cell types by AAVs. Here, we analyzed the efficiencies of transduction and the transport mechanisms of AAV type 2 (AAV-2) in different cell types, emphasizing endothelial cells. Expression analyses in both cultured cells and the rabbit carotid artery assay showed a remarkably low level of endothelial cell transduction in comparison to the highly permissive cell types. The study of the endosomal pathways of AAV-2 with fluorescently labeled virus showed clear targeting of the Golgi area in permissive cell lines, but this phenomenon was absent in the endothelial cell line EAhy-926. On the other hand, the response to the block of endosomal acidification by bafilomycin A1 also showed differences among the permissive cell types. We also analyzed the effect of proteasome inhibitors on endothelial cells, but their impact on the primary cells and in vivo was not significant. On the contrary, analysis of the expression pattern of heparan sulfate proteoglycans (HSPGs), the primary receptors of AAV-2, revealed massive deposits of HSPG in the extracellular matrix of endothelial cells. The matrix-associated receptors may therefore compete for virus binding and reduce transduction in endothelial cells. Accordingly, in endothelial cells detached from their matrix, AAV-2 transduction was significantly increased. Altogether, these results point to a more complex cell-type-specific mode of transduction of AAV-2 than previously appreciated.
Vascular aging is mainly characterized by endothelial dysfunction. We found decreased free nitric oxide (NO) levels in aged rat aortas, in conjunction with a sevenfold higher expression and activity of endothelial NO synthase (eNOS). This is shown to be a consequence of age-associated enhanced superoxide (·O2−) production with concomitant quenching of NO by the formation of peroxynitrite leading to nitrotyrosilation of mitochondrial manganese superoxide dismutase (MnSOD), a molecular footprint of increased peroxynitrite levels, which also increased with age. Thus, vascular aging appears to be initiated by augmented ·O2− release, trapping of vasorelaxant NO, and subsequent peroxynitrite formation, followed by the nitration and inhibition of MnSOD. Increased eNOS expression and activity is a compensatory, but eventually futile, mechanism to counter regulate the loss of NO. The ultrastructural distribution of 3-nitrotyrosyl suggests that mitochondrial dysfunction plays a major role in the vascular aging process.
vascular aging; superoxide; nitric oxide; 3-nitrotyrosine; vascular endothelium