In Vivo Fluorine Imaging Using 1.5 Tesla MRI for Depiction of Experimental Myocarditis in a Rodent Animal Model.

The usefulness of perfluorocarbon nanoemulsions for the imaging of experimental myocarditis has been demonstrated in a high-field 9.4 Tesla MRI scanner. Our proof-of-concept study investigated the imaging capacity of PFC-based 19F/1H MRI in an animal myocarditis model using a clinical field strength of 1.5 Tesla. To induce experimental myocarditis, five male rats (weight ~300 g, age ~50 days) were treated with one application per week of doxorubicin (2 mg/kg BW) over a period of six weeks. Three control animals received the identical volume of sodium chloride 0.9% instead. Following week six, all animals received a single 4 ml injection of an 20% oil-in-water perfluorooctylbromide nanoemulsion 24 hours prior to in vivo1H/19F imaging on a 1.5 Tesla MRI. After euthanasia, cardiac histology and immunohistochemistry using CD68/ED1 macrophage antibodies were performed, measuring the inflamed myocardium in µm2 for further statistical analysis to compare the extent of the inflammation with the 19F-MRI signal intensity. All animals treated with doxorubicin showed a specific signal in the myocardium, while no myocardial signal could be detected in the control group. Additionally, the doxorubicin group showed a significantly higher SNR for 19F and a stronger CD68/ED1 immunhistoreactivity compared to the control group. This proof-of-concept study demonstrates that perfluorocarbon nanoemulsions could be detected in an in vivo experimental myocarditis model at a currently clinically relevant field strength.

Systematic Scoring Balloon Lesion Preparation for Drug-Coated Balloon Angioplasty in Clinical Routine: Results of the PASSWORD Observational Study.

INTRODUCTION: Scoring balloon angioplasty (SBA) for lumen gain prior to stent implantations or drug-coated balloon angioplasty (DCB) is considered an essential interventional tool for lesion preparation. Recent evidence indicates that SBA may play a pivotal role in enhancing the angiographic and clinical outcomes of DCB angioplasty. METHODS: We studied the systematic use of SBA with a low profile, non-slip element device prior to DCB angioplasty in an unselected, non-randomized patient population. This prospective, all-comers study enrolled patients with de novo lesions as well as in-stent restenotic lesions in bare metal stents (BMS-ISR) and drug-eluting stents (DES-ISR). The primary endpoint was the target lesion failure (TLF) rate at 9 months (ClinicalTrials.gov Identifier NCT02554292). RESULTS: A total of 481 patients (496 lesions) were recruited to treat de novo lesions (78.4%, 377), BMS-ISR (4.0%, 19), and DES-ISR (17.6%, 85). Overall risk factors were acute coronary syndrome (ACS, 20.6%, 99), diabetes mellitus (46.8%, 225), and atrial fibrillation (8.5%, 41). Average lesion lengths were 16.7 ± 10.4 mm in the de novo group, and 20.1 ± 8.9 mm (BMS-ISR) and 16.2 ± 9.8 mm (DES-ISR) in the ISR groups. Scoring balloon diameters were 2.43 ± 0.41 mm (de novo), 2.71 ± 0.31 mm (BMS-ISR), and 2.92 ± 0.42 mm (DES-ISR) whereas DCB diameters were 2.60 ± 0.39 mm (de novo), 3.00 ± 0.35 mm (BMS-ISR), and 3.10 ± 0.43 mm (DES-ISR), respectively. The overall accumulated TLF rate of 3.0% (14/463) was driven by significantly higher target lesion revascularization rates in the BMS-ISR (5.3%, 1/19) and the DES-ISR group (6.0%, 5/84). In de novo lesions, the TLF rate was 1.1% (4/360) without differences between calcified and non-calcified lesions (p = 0.158) and small vs. large reference vessel diameters with a cutoff value of 3.0 mm (p = 0.901). CONCLUSIONS: The routine use of a non-slip element scoring balloon catheter to prepare lesions suitable for drug-coated balloon angioplasty is associated with high procedural success rates and low TLF rates in de novo lesions.

Routine Transesophageal Echocardiography in Atrial Fibrillation Before Electrical Cardioversion to Detect Left Atrial Thrombosis and Echocontrast.

BACKGROUND: Transesophageal echocardiography (TEE) before electrical cardioversion (ECV) in atrial fibrillation (AF) is not routinely performed in anticoagulated patients. METHODS: Starting from TEE findings of anticoagulated and non-anticoagulated patients referred for ECV, we investigated the rate of spontaneous echo-contrast (SEC) and left atrial thrombus (LAT) and identified their independent predictors. RESULTS: A total of 403 patients were included: 262 (65%) had no anticoagulation, 47 (11.7%) were onnovel oral anticoagulant (rivaroxaban), 74 (18.4%) on warfarin INR>2, and 20 (5.0%) on warfarin INR<2.In 41 (10.1%) there was LAT and in 154 (38.2%) SEC. Patients with LAT had a significantly lower left ventricular ejection fraction (LVEF%) (p=0.001). Patients with SEC were significantly older (p=0.04), had lower LVEF% (p<0.0001),higher CHADSVASC score (p<0.0001), and higher rate of coronary artery disease (CAD) (p=0.03). In 56.8% of warfarin patients (INR>2) there was SEC (p=0.002). At multivariate analysis therapeutic anticoagulation with warfarin (p=0.003; OR:2.2; CI: 1.3-3.7),CHADSVASC score (p<0.0001; OR=1.2; CI: 1.1-1.4), and LVEF% (p<0.0001; OR:0.95; CI: 0.93-0.97; inverse relationship) were SEC predictors. A 3.5 CHADSVASC score cut-off was predictor of SEC (AUC: 0.7; p<0.0001). LVEF% was the only predictor of LAT (p=0.02; OR=0.96; CI: 0.93-0.99; inverse relationship). CONCLUSIONS: Echocardiography before ECV identifies clear LAT/SEC in more than a third of AF patients, independently by their anticoagulation regimen. LAT/SEC rates increasewith decrement of LVEF%. Increment of CHADSVASC score increases SEC risk. In anticoagulated patients SEC rate remains higher than expected. Therapeutic anticoagulation with Warfarin appears positively and independently correlated to SEC occurrence.

Coronary artery treatment with a urea-based paclitaxel-coated balloon: the European-wide FALCON all-comers DCB Registry (FALCON Registry).

AIMS: The aim of this study was to investigate the use of a drug-coated balloon (DCB) in daily clinical practice and provide further evidence on the safety and efficacy of paclitaxel-coated balloon treatment using urea as an inert excipient. METHODS AND RESULTS: Between December 2013 and December 2015, 757 patients treated for coronary lesions with the IN.PACT Falcon balloon were enrolled in this prospective real-world all-comers registry. The primary outcome was the clinically driven target lesion revascularisation (TLR) rate at 12 months. The secondary outcome was major adverse cardiac events (MACE) defined as cardiac death, myocardial infarction, TLR and target vessel revascularisation (TVR). Out of 805 lesions, 43.1% were de novo, and 53.2% drug-eluting stent (DES) or bare metal stent (BMS) in-stent restenosis (ISR). TLR at 12 months was 6.2% and TVR 8.3%. MACE occurred in 9.7% of patients with a composite of cardiac death in 0.8% and myocardial infarction in 2.7% plus TLR/TVR. Subgroup analysis confirmed a TLR rate of 7.5% for ISR (2.1% BMS and 9.5% DES) and 4.9% for de novo lesions. CONCLUSIONS: The IN.PACT Falcon urea-based paclitaxel-coated balloon is safe and efficient in de novo and ISR lesions with low rates of TLR/TVR. The high proportion of treatment of de novo lesions indicates that a DCB-only strategy is nowadays common.

Do acute coronary events affect lipid management and cholesterol goal attainment in Germany? : Results from the Dyslipidemia International study II.

OBJECTIVE: To document utilization of lipid-lowering therapy, attainment of low-density lipoprotein cholesterol target values, and cardiovascular outcomes in patients hospitalized for acute coronary syndrome in Germany. METHODS: The Dyslipidemia International Study II was a multicenter, observational study of the prevalence of dyslipidemia and lipid target value attainment in patients surviving any acute coronary syndrome event. Among patients on lipid-lowering therapy for ≥3 months, use of lipid-lowering therapy and lipid profiles were assessed at admission and again at 120 ± 15 days after admission (the follow-up time point). Multivariate logistic regression was used to identify variables predictive of low-density lipoprotein cholesterol target value attainment in patients using lipid-lowering therapy. RESULTS: A total of 461 patients hospitalized for acute coronary syndrome were identified, 270 (58.6%) of whom were on lipid-lowering therapy at admission. Among patients on lipid-lowering therapy, 90.7% and 85.9% were receiving statin monotherapy at admission and follow-up, respectively. Mean (SD) low-density lipoprotein cholesterol levels in patients on lipid-lowering therapy were 101 (40) mg/dl and 95 (30) mg/dl at admission and follow-up, respectively. In patients with data at both admission and follow-up (n = 61), low-density lipoprotein cholesterol target value attainment rates were the same (19.7%) at both time points. Smoking was associated with a 77% lower likelihood of attaining the low-density lipoprotein cholesterol target value. CONCLUSION: Hospitalization for an acute event does not greatly alter lipid management in acute coronary syndrome patients in Germany. Both lipid-lowering therapy doses and rates of low-density lipoprotein cholesterol target value attainment remained essentially the same several months after the event.

Clopidogrel pharmacokinetics and pharmacodynamics in out-of-hospital cardiac arrest patients with acute coronary syndrome undergoing target temperature management.

BACKGROUND: Target temperature management (TTM) after cardiac arrest (CA) improves outcome in patients with acute coronary syndrome (ACS). Previous data point to an interaction between hypothermia and drug metabolism, potentially impacting on platelet function in patients on antiplatelet therapy. PURPOSE: To compare clopidogrel metabolism and platelet function in clopidogrel naïve ACS patients treated with TTM (33°C, n=15) and in ACS patients (troponin positive) without TTM (n=18). METHODS: Platelet function was measured by multiple electrode platelet aggregometry (MEA), light transmittance aggregometry (LTA) and VASP analysis before and after administration of a 600mg clopidogrel loading dose. Plasma levels of clopidogrel and its metabolites were measured. All patients were screened for CYP2C19*2 polymorphism and scheduled for PCI. TTM was carried out for 24h at a target temperature of 33°C using a computer feedback surface cooling device in cardiac arrest patients. RESULTS: Plasma concentration of clopidogrel and metabolites was lower in the TTM group after 2 and 4h, respectively (all p<0.005 vs. controls), and platelet function tests revealed an attenuated response to clopidogrel with respect to baseline platelet activity in the TTM group. This was significant for MEA, LTA and VASP analysis (all p<0.05). Moreover, there was no significant difference in genotype and platelet function determined ex vivo at 33 or 37°C, respectively. CONCLUSION: Inhibition of platelet function is significantly lessened in TTM at 33°C, likely due to reduced clopidogrel absorption. Patients with TTM might thus have a higher risk for further cardiovascular events despite antiplatelet therapy with clopidogrel.

Coronary artery treatment with paclitaxel-coated balloon using a BTHC excipient: clinical results of the international real-world DELUX registry.

AIMS: Safety and efficacy of percutaneous coronary interventions using the Pantera Lux paclitaxel-coated balloon have been demonstrated in the PEPPER first-in-man trial. This prospective, multicentre, clinical registry aims to evaluate its safety and efficacy in an international real-world setting in a larger cohort of patients. METHODS AND RESULTS: Between April 2010 and April 2011, 1,064 patients were treated for predominantly diffuse and proliferative in-stent restenosis of bare metal stents (BMS-ISR) and drug-eluting stents (DES-ISR), or for de novo lesions. Clinical device success was obtained in 98.2% of the patients. The study endpoint was major adverse cardiac events (MACE), defined as a composite of all-cause mortality, non-fatal myocardial infarction and clinically driven target vessel revascularisation, and was 8.5% in the overall, 6.0% in the BMS-ISR, 11.5% in the DES-ISR and 7.0% in the de novo population at six months, and 15.1%, 11.6%, 20.6% and 9.4% at 12 months, respectively. Definitive stent thrombosis occurred in 0.4% of the patients within 12 months. CONCLUSIONS: Safety and efficacy of the Pantera Lux paclitaxel-coated balloon was confirmed in a real-world setting with low major adverse cardiac event rates in patients with in-stent restenosis or de novo lesions. (ClinicalTrials.gov: NCT01081366).

Reproducibility of small animal cine and scar cardiac magnetic resonance imaging using a clinical 3.0 tesla system.

BACKGROUND: To evaluate the inter-study, inter-reader and intra-reader reproducibility of cardiac cine and scar imaging in rats using a clinical 3.0 Tesla magnetic resonance (MR) system. METHODS: Thirty-three adult rats (Sprague-Dawley) were imaged 24 hours after surgical occlusion of the left anterior descending coronary artery using a 3.0 Tesla clinical MR scanner (Philips Healthcare, Best, The Netherlands) equipped with a dedicated 70 mm solenoid receive-only coil. Left-ventricular (LV) volumes, mass, ejection fraction and amount of myocardial scar tissue were measured. Intra-and inter-observer reproducibility was assessed in all animals. In addition, repeat MR exams were performed in 6 randomly chosen rats within 24 hours to assess inter-study reproducibility. RESULTS: The MR imaging protocol was successfully completed in 32 (97%) animals. Bland-Altman analysis demonstrated high intra-reader reproducibility (mean bias%: LV end-diastolic volume (LVEDV), -1.7%; LV end-systolic volume (LVESV), -2.2%; LV ejection fraction (LVEF), 1.0%; LV mass, -2.7%; and scar mass, -1.2%) and high inter-reader reproducibility (mean bias%: LVEDV, 3.3%; LVESV, 6.2%; LVEF, -4.8%; LV mass, -1.9%; and scar mass, -1.8%). In addition, a high inter-study reproducibility was found (mean bias%: LVEDV, 0.1%; LVESV, -1.8%; LVEF, 1.0%; LV mass, -4.6%; and scar mass, -6.2%). CONCLUSIONS: Cardiac MR imaging of rats yielded highly reproducible measurements of cardiac volumes/function and myocardial infarct size on a clinical 3.0 Tesla MR scanner system. Consequently, more widely available high field clinical MR scanners can be employed for small animal imaging of the heart e.g. when aiming at serial assessments during therapeutic intervention studies.

Lack of relationship between cord serum angiopoietin-like protein 4 (ANGPTL4) and lipolytic activity in human neonates born by spontaneous delivery.

BACKGROUND: Ligands of peroxisome-proliferator activated receptors (PPARs), such as non-esterified fatty acids (NEFAs), induce expression of angiopoietin-like protein 4 (ANGPTL4). Recently ANGPTL4 has been reported to be a mediator of intracellular adipose lipolysis induced by glucocorticoids. OBJECTIVE: To determine the concentrations of ANGPTL4 in cord serum of neonates born by spontaneous vaginal delivery (SVD) and by pre-labor cesarean section (CS) from healthy women, and to relate them to parameters of neonatal lipolytic activity at birth. MEASUREMENTS: In 54 neonates born by SVD and in 56 neonates born by CS, arterial cord blood was drawn to determine insulin, cortisol, triacylglycerols (TAGs), glycerol, non-esterified fatty acids (NEFAs), individual fatty acids, ANGPTL4, adiponectin, retinol binding protein 4 (RBP4) and leptin. RESULTS: Birth weight and neonatal fat mass in SVD and CS showed no difference, but the concentrations of glycerol, adiponectin, RBP4, NEFAs and most individual fatty acids were higher in cord serum of neonates born by SVD compared to CS, indicating a higher adipose tissue breakdown in the SVD group. The concentrations of TAG and cortisol were also higher and that of insulin was lower in cord serum of SVD compared to the CS group. However, the concentration in cord serum of ANGPTL4 did not differ between the two groups and no positive correlation with either NEFA or glycerol concentrations were detected. CONCLUSION: ANGPTL4 is known to stimulate lipolysis in adults, but does not appear to mediate the increased activity in SVD, indicating the presence of different regulatory inputs.

Soluble P-selectin level correlates with acetylsalicylic acid but not with clopidogrel response in patients with stable coronary artery disease after a percutaneous coronary intervention.

BACKGROUND: Impaired response to dual antiplatelet therapy is associated with worse cardiovascular outcome. Besides antiplatelet effects, there is evidence that both clopidogrel and acetylsalicylic acid (ASA) have anti-inflammatory properties. However, little is known about the relationship between platelet function and inflammation under dual antiplatelet therapy in patients with stable coronary artery disease. PURPOSE: The purpose of the study was to investigate the correlation of platelet function with soluble (s)P-selectin and soluble (s)CD40L in patients undergoing elective percutaneous coronary intervention. Poor response to ASA and clopidogrel could lead to increased levels of inflammatory markers. METHODS: A total of 148 patients were included. Eighty percent of the patients were on 100 mg ASA and all patients were clopidogrel naive. They underwent percutaneous coronary intervention and received a loading dose of 600 mg clopidogrel. Platelet function was assessed by light transmittance aggregometry (LTA) and vasodilator-stimulated phosphoprotein analysis at baseline, 24 h after loading, and after 1 month of maintenance therapy, respectively. Plasma levels of sP-selectin and sCD40L were measured. To classify low responders to clopidogrel, patients were screened for genetic variants determining clopidogrel absorption and metabolization. RESULTS: sP-selectin levels correlated with LTA findings after stimulation with arachidonic acid (P=0.012). Further, in addition to decreased platelet reactivity observed on LTA, lower sP-selectin levels were seen in patients under ASA therapy (P=0.004). CYP2C19*2 allele carriers had a higher platelet reactivity after clopidogrel loading measured by adenosine diphosphate-induced aggregation in LTA (P=0.008) and vasodilator-stimulated phosphoprotein phosphorylation (P=0.035); however, there was no difference in the inflammatory markers. Multiple regression analysis showed that variables significantly related to sP-selectin plasma levels were sCD40L (P<0.001), LTA after stimulation with arachidonic acid (P<0.001), adenosine diphosphate (20 µmol/l, P=0.009), collagen (P<0.001), and ejection fraction (P=0.001). CONCLUSION: sP-selectin was decreased in patients receiving ASA but did not reflect a CYP2C19*2-defined clopidogrel response. This underlines that sP-selectin is a useful marker for ASA, but not for clopidogrel response, in stable coronary artery disease.

Local delivery of IL-2 reduces atherosclerosis via expansion of regulatory T cells.

OBJECTIVE: Recent studies indicate that regulatory T cells (Tregs) attenuate murine atherosclerosis. Since interleukin (IL)-2 induces Tregs proliferation, we tested the impact of L19-IL2, a fusion antibody specific to extra-domain B of fibronectin (ED-B) containing an active human IL-2 molecule, in experimental atherosclerosis. METHODS AND RESULTS: L19-IL2 or appropriate controls were given intravenously to 6 month old Western diet-fed apoE(-/-) mice on day 1, 3, and 5. Human IL-2 was detected on day 7 within atherosclerotic plaques of L19-IL2-treated mice, and magnetic resonance imaging of the plaques showed a significant adventitial gadolinium enhancement on day 7 and 13, suggesting microvascular leakage as a result of the pharmacodynamic activity of L19-IL2. Treatment with L19-IL2 significantly reduced the size of pre-established atherosclerotic plaques at the thoracic aorta (Sudan III stained area) and in the aortic root area (microscopic, morphometric analysis) on day 7 as compared to controls (L19, D1.3-IL2, NaCl) as well as compared to baseline (day 0). Tregs markers Foxp3 and CTLA4 were highly increased in plaques after L19-IL2 treatment compared to controls (p<0.01), whereas the macrophage marker Mac3 was significantly reduced (p<0.03). Co-treatment with IL-2-receptor blocking antibody PC61 abrogated L19-IL2-induced plaque reduction compared with IgG control (p<0.03). CONCLUSION: L19-IL2 delivers functional IL-2 to pre-established atherosclerotic plaques of WD-fed apoE(-/-) mice resulting in significant plaque size reduction mediated by local Tregs.

Gestational diabetes mellitus causes changes in the concentrations of adipocyte fatty acid-binding protein and other adipocytokines in cord blood.

OBJECTIVE: To determine the concentrations of adipocyte fatty acid-binding protein (AFABP) and other adipocytokines in maternal and cord serum of pregnant women with gestational diabetes mellitus (GDM) and of control subjects and to relate them to indexes of insulin sensitivity. RESEARCH DESIGN AND METHODS: In 86 control and 98 GDM pregnant women, venous blood was collected before vaginal delivery and arterial blood from cord immediately after delivery. Serum insulin and adipocytokines were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: GDM women had higher prepregnancy BMI, and data were adjusted for it. Maternal serum insulin, insulin-to-glucose ratio, homeostasis model assessment (HOMA), AFABP, and retinol-binding protein 4 (RBP4) were higher and adiponectin was lower in GDM than in control subjects, whereas serum glucose, insulin, insulin-to-glucose ratio, HOMA, nonesterified fatty acids, and RBP4 were higher and glycerol, AFABP, and adiponectin were lower in cord blood serum of GDM than of control subjects. AFABP and adiponectin in cord serum of control subjects were higher than in maternal serum; in GDM women no difference was found for AFABP in cord versus maternal serum, although adiponectin remained higher in cord. Values of leptin in both groups were lower in cord than in maternal serum, and those of RBP4 were lower in only GDM women. CONCLUSIONS: It is suggested that fetal tissues are the main source of cord arterial serum AFABP, and in GDM fetuses AFABP values correlate with adiposity markers. A downregulation of adiponectin and upregulation of RBP4 in GDM mothers and their fetuses may be related to their insulin-resistant condition, whereas changes in AFABP do not seem to be related.

Evaluation of contrast wash-in and peak enhancement in adenosine first pass perfusion CMR in patients post bypass surgery.

BACKGROUND: Adenosine first pass perfusion cardiovascular magnetic resonance (CMR) yields excellent results for the detection of significant coronary artery disease (CAD). In patients with coronary artery bypass grafts (CABG) the kinetics of a contrast bolus may by altered only due to different distances through the bypass grafts compared to native vessels, thereby possibly imitating a perfusion defect. The aim of the study was to evaluate semiquantitative perfusion parameters in order to assess possible differences in epicardial contrast kinetics in areas supplied by native coronaries and CABG, both without significant stenosis. METHODS: Twenty patients with invasive exclusion of significant CAD (control group) and 38 patients with CABG without angiographically significant (>or=50%) stenosis in unbypassed coronaries or grafts were retrospectively included in the study. They underwent adenosine first pass (0.05 mmol/kg Gd-DTPA) perfusion (3 short axis views/heart beat) and late gadolinium enhancement (LGE) imaging 1 day before invasive coronary angiography. Areas perfused by native coronaries and/or the different bypasses were identified in X-ray angiography using the 16 segment model. In each of these areas upslope and maximal signal intensity (SImax) relative to the left ventricular parameters, time to 50% maximal signal intensity (TSI50%max) and time to maximal signal intensity (TSImax) were calculated. RESULTS: In areas perfused by coronary arteries with bypasses compared to native coronaries relative upslope and relative SImax did not show a significant difference. TSI50%max and TSImax in native coronaries and bypasses were 7.2s +/- 1.9s vs. 7.5s +/- 1.9s (p < 0.05) and 12.6s +/- 3.0s vs. 13.1s +/- 3.0s (p < 0.05), respectively. The delay in Tmax resulted in a significant (p < 0.05) delay of 0.5 +/- 1.1 heart beats (=images) when adjusted to the heart rate. Differences in time were most pronounced in areas perfused by left internal mammary artery grafts rather than by venous CABG, but were also present between native vessel territories in patients without CAD, albeit with smaller variability. CONCLUSION: Adenosine perfusion CMR in patients post CABG may be associated with a short delay in contrast arrival. However, once the contrast is in the myocardium there is similar wash-in kinetics and peak enhancement. Therefore, since the delay is only short, the possibly differing contrast kinetics through grafts and native vessels does not seem to be a limiting factor for the accuracy of first pass adenosine perfusion in patients post CABG.

High resolution magnetic resonance imaging in atherosclerotic mice treated with ezetimibe.

High field magnetic resonance imaging (MRI) was performed to investigate the long-term effect of ezetimibe (eze), a cholesterol resorption blocker, on atherosclerotic lesion formation in the thoracic aorta of apolipoprotein E-deficient mice (apoE ( -/- )) in comparison to wild type mice (WT). Fifteen-month-old apoE ( -/- ) (Western type diet), apoE ( -/-eze ) (Western type diet with eze) which received eze (5 mc/kg/day) continuously, and age-matched WT (normal chow) were studied using contrast-enhanced 3D turbo-spin-echo sequences (RARE factor 2) on a 7 Tesla scanner. Vessel parameters were analyzed in the aortic root (AR) and aortic arch (AA) and compared to those found in histology. Plasma cholesterol levels were reduced at 15 months by 71% (P < 0.01) in apoE ( -/-eze ) compared to apoE ( -/- ). Vessel wall thickness was increased in the AR and AA in apoE ( -/- ) by 189.1 and 147.2%, respectively compared to WT. ApoE ( -/-eze ) showed reduced wall thickness in the AR (127.4%) and AA (102.8%, both P < 0.05 vs. apoE ( -/- )). A significant increase in total aortic vessel area was determined in the AR and AA in apoE ( -/- ) by 134.7 and 118.3%, respectively, compared to WT. This effect was inhibited in apoE ( -/-eze ) (AR: 126.7%, AA: 86.4%, both P < 0.05). Histological analysis confirmed the effect of eze observed by MRI and demonstrated a significant correlation between the two techniques (P < 0.001). MRI demonstrates that ezetimibe significantly reduces atherosclerotic disease in apoE ( -/- ). MRI is therefore a useful technique to perform in vivo interventional studies in experimental atherosclerosis.

Magnetic resonance adenosine perfusion imaging in patients after coronary artery bypass graft surgery.

OBJECTIVES: The aim of the study was to evaluate the feasibility and diagnostic performance of the combination of adenosine stress perfusion and late gadolinium enhancement (LGE) in patients after coronary artery bypass graft surgery (CABG). BACKGROUND: Cardiac magnetic resonance (CMR) imaging allows the detection of significant coronary artery disease by adenosine stress perfusion and infarct imaging. Myocardial contrast kinetics may be altered in patients after CABG owing to more complex myocardial perfusion and different distances of the contrast bolus through different bypasses and native coronary vessels. Additionally, all studies have excluded patients after CABG. METHODS: In all, 78 patients (age 66 +/- 8 years; 71 men) underwent CMR imaging including left ventricular function, first-pass adenosine stress perfusion (adenosine 140 microg/min/kg) using 0.05 mmol/kg body weight gadolinium-diethylenetriaminepenta-acetic acid and an additional 0.15 mmol/kg for LGE 1 day before invasive coronary angiography. Images were analyzed visually using the speed of contrast wash-in and maximal signal intensity. Transmural LGE defects of the size of a vessel or graft territory defined by angiography were considered true negatives, even when supplied by a stenosed/occluded vessel/graft. Stenoses >50% in grafts and grafted or ungrafted native vessels (diameter > or =2 mm) in invasive angiography were considered significant. RESULTS: The prevalence of patients with significant stenosis was 63% (69% functionally 1-vessel, 28% 2-vessel, and 3% 3-vessel disease). Sensitivity and specificity were 77% and 90%, respectively, on a patient basis, and 71% and 89% on a vessel territory basis. Sensitivity, if only areas supplied by grafts (n = 196) were evaluated, was 78% and specificity was 94%, compared with territories supplied by ungrafted native vessels (n = 51) with sensitivity and specificity of 63% and 91%, respectively. Sensitivity and specificity for the 53 areas with prior infarction were 88% and 79%, respectively. CONCLUSIONS: For patients after surgical revascularization, the combination of stress perfusion and LGE yields good diagnostic accuracy for the detection and localization of significant stenoses. However, sensitivity is reduced compared with published data in patients without CABG. Prior myocardial infarction can be examined without loss of accuracy.

Integrin cleavage facilitates cell surface-associated proteolysis required for vascular smooth muscle cell invasion.

Vascular smooth muscle cell (VSMC) invasion is a key element in atherogenesis and restenosis, requiring integrins for adhesion/de-adhesion as well as matrix metalloproteinases (MMPs) for focalized proteolysis. Among the MMP family, pro-MMP-2 is unique in its activation, depending on the formation of a multiprotein complex with MT1-MMP/TIMP-2 at the cell surface, in which integrin alphavbeta3 participates. Integrin alphav and MT1-MMP are synthesized from precursors via furin-dependent cleavage of their pro-peptide. Furin is the prototypical proprotein convertase highly expressed in VSMCs and human atherosclerotic lesions. Its precise role in the tight network involving MMPs/integrins and their coordination and cooperation required for VSMC invasion is unknown. We demonstrate that furin-inhibition with decanoyl-RVKR-chloromethylketone inhibits VSMC invasion in a comparable degree to MMP inhibitors, which reduce the MT1-MMP-MMP-2 proteolytic cascade. Furin-inhibition did not prevent MT1-MMP/MMP-2 maturation. In contrast, it strongly reduced pro-alphav cleavage, but did not lessen its cell membrane expression. However, inhibition of pro-alphav processing via furin-inhibition strongly reduced pro-MMP-2 binding to the cell surface, thereby lessening its full maturation and diminishing the cell surface in situ proteolysis required for invasion. Thus, our data demonstrate a novel mechanism of furin-dependent alphav cleavage that enhances pro-MMP-2 binding and activation at the cell membrane in cooperation with MT1-MMP in primary VSMCs. Processing of alphav by furin contributes to the recruitment of enzymatic energy to the cell surface, thereby providing focalized proteolysis associated with VSMC invasion.

Angiotensin II type 2 receptor stimulation: a novel option of therapeutic interference with the renin-angiotensin system in myocardial infarction?

BACKGROUND: This study is the first to examine the effect of direct angiotensin II type 2 (AT(2)) receptor stimulation on postinfarct cardiac function with the use of the novel nonpeptide AT(2) receptor agonist compound 21 (C21). METHODS AND RESULTS: Myocardial infarction (MI) was induced in Wistar rats by permanent ligation of the left coronary artery. Treatment with C21 (0.01, 0.03, 0.3 mg/kg per day IP) was started 24 hours after MI and was continued until euthanasia (7 days after MI). Infarct size was assessed by magnetic resonance imaging, and hemodynamic measurements were performed via transthoracic Doppler echocardiography and intracardiac Millar catheter. Cardiac tissues were analyzed for inflammation and apoptosis markers with immunoblotting and real-time reverse transcription polymerase chain reaction. C21 significantly improved systolic and diastolic ventricular function. Scar size was smallest in the C21-treated rats. In regard to underlying mechanisms, C21 diminished MI-induced Fas-ligand and caspase-3 expression in the peri-infarct zone, indicating an antiapoptotic effect. Phosphorylation of the p44/42 and p38 mitogen-activated protein kinases, both involved in the regulation of cell survival, was strongly reduced after MI but almost completely rescued by C21 treatment. Furthermore, C21 decreased MI-induced serum monocyte chemoattractant protein-1 and myeloperoxidase as well as cardiac interleukin-6, interleukin-1beta, and interleukin-2 expression, suggesting an antiinflammatory effect. CONCLUSIONS: Direct AT(2) receptor stimulation may be a novel therapeutic approach to improve post-MI systolic and diastolic function by antiapoptotic and antiinflammatory mechanisms.

Monitoring therapeutical intervention with ezetimibe using targeted near-infrared fluorescence imaging in experimental atherosclerosis.

Ezetimibe (EZE), an inhibitor of cholesterol absorption, reduces atherosclerosis in apolipoprotein E-deficient (apoE(-/-)) mice. The matrix protein ED-B fibronectin (ED-B) is upregulated in atherosclerotic lesions. Using a novel conjugate for near-infrared fluorescence (NIRF) imaging targeting ED-B, we studied the effect of EZE on plaque lesion formation in apoE(-/-) mice. ApoE(-/-) mice received EZE (5 mug/kg/d) or chow up to the age of 4, 6, and 8 months. NIRF imaging of aortic lesions was performed 24 hours after intravenous application ex vivo and in vivo. Plaque lesion formation was analyzed by histology and immunohistochemistry. Aortic lesion formation detected by Sudan staining and NIRF imaging was significantly reduced at 6 and 8 months (p < .001). Plaque areas determined by NIRF imaging significantly correlated with Sudan staining (p < .001). EZE treatment resulted in a significant reduction in plaque macrophage and ED-B immunoreactivity (both p < .05) in brachiocephalic lesions. There was a significant reduction in plaque size in brachiocephalic arteries in 8-month-old mice treated with EZE compared with mice during short-term treatment (p < .05), indicating EZE plaque regression. Targeted NIRF imaging showed a correlation to histologic lesion extension during therapeutical intervention in experimental atherosclerosis.