Emmanuelle Canet-soulas - Academia.edu (original) (raw)

Papers by Emmanuelle Canet-soulas

Biomechanics of Coronary Atherosclerotic Plaque

Abstract Animal models have been extensively used to understand atherogenesis and the complex bio... more Abstract Animal models have been extensively used to understand atherogenesis and the complex biological mechanisms of atherosclerosis. Yet, their advanced plaque morphologies may have distinct features from human coronary lesions and strikingly, they often do not lead to acute cardiac events, at least in mice models. These particularities will be presented in the major models of advanced plaques together with their respective specific localizations. Next, in light of recent major translational advances regarding the role of inflammation in plaque vulnerability, the main findings from animal models to human applications will be given, opening new diagnoses and therapeutic targets. Finally, biomechanics has mainly been evaluated in human plaques, but differences and similarities between animal models and human lesions shed new light on prediction markers of acute events.

ABSTRACTMicroglial phagocytosis is rapidly emerging as a therapeutic target in neurodegenerative ... more ABSTRACTMicroglial phagocytosis is rapidly emerging as a therapeutic target in neurodegenerative and neurological disorders. An efficient removal of cellular debris is necessary to prevent buildup damage of neighbor neurons and the development of an inflammatory response. As the brain professional phagocytes, microglia are equipped with an array of mechanisms that enable them to recognize and degrade several types of cargo, including neurons undergoing apoptotic cell death. While microglia are very competent phagocytes of apoptotic cells under physiological conditions, here we report their dysfunction in mouse and monkey (Macaca fascicularis and Callithrix jacchus) models of stroke by transient occlusion of the medial cerebral artery (tMCAo). The impairment of both engulfment and degradation was related to energy depletion triggered by oxygen and nutrients deprivation (OND), which led to reduced process motility, lysosomal depletion, and the induction of a protective autophagy respo...

European Journal of Applied Physiology, 2016

± 1.06 µg/mL) than in sedentary lean participants (7.44 ± 1.06 µg/mL; both p < 0.05). Training re... more ± 1.06 µg/mL) than in sedentary lean participants (7.44 ± 1.06 µg/mL; both p < 0.05). Training reduced total and high-molecular-weight adiponectin concentrations by, respectively, −32 and −42 % in sedentary lean, and −26 and −35 % in sedentary overweight, while detraining increased them by +25 and +27 % in active lean participants. Total and high-molecular-weight adiponectin changes were inversely correlated with VO 2peak changes (respectively, R 2 = 0.45, R 2 = 0.59; both p < 0.001) and positively with changes in fasting plasma insulin (both p < 0.05). Muscle and adipose tissue adiponectin mRNA did not differ between groups and with interventions. Muscle AdipoR2 and APPL1 mRNAs were lower in sedentary groups compared with the active group; and were positively associated with VO 2peak and inversely with fasting plasma insulin concentration. Conclusion Plasma adiponectin concentration is inversely correlated with aerobic capacity. Future investigations will need to confirm the contribution of changes in muscle adiponectin sensitivity. Keywords Multimeric forms • Adiponectin receptors • Exercise • Body weight • Aerobic fitness Abbreviations AMPK AMP-activated protein kinase APPL1 Adaptor protein, phosphotyrosine interaction, PH domain and leucine zipper containing 1 BMI Body mass index ELISA Enzyme-linked immunosorbent assay FFM Fat-free mass FM Fat mass HMW High molecular weight LMW Low molecular weight MMW Medium molecular weight

Introduction Simultaneous lung ventilation/perfusion imaging techniques using hyperpolarized (HP)... more Introduction Simultaneous lung ventilation/perfusion imaging techniques using hyperpolarized (HP) 3 He have been successfully applied and demonstrated on small animals [1,2]. These techniques are based on the increased helium transverse magnetization dephasing rate induced by an intravascular contrast agent such as super-paramagnetic iron oxide nano-particle (SPIO). However, these techniques require a relatively large concentration of contrast agent and long echo time that may limit their applicability for human studies. In this work, we propose a new sequence based on stimulated echoes acquisition. This STEAM-based sequence takes advantage of the long helium T 1 values and allows acquisition of perfusion-weighted image with improved sensitivity to intravascular contrast agent. Methods The diagram of the modified STEAM sequence is presented in Figure 1. Non-selective pulses were used. Following the first two 90° pulses, a series of low α flip angle followed by radial imaging encodin...

International audienceIntroduction The grey mouse lemur is an interesting alternative to transgen... more International audienceIntroduction The grey mouse lemur is an interesting alternative to transgenic models for the study of normal and pathological ageing [1]: aged animals (>5 years old) spontaneously and progressively develop sensori-motor deficits, alterations of biological rhythms, of thermal regulation, of metabolism, as well as cognitive decline and cerebral atrophy [2]. We here report for the first time aged-related vascular abnormalities, as detected by ultrasound imaging (US) performed at different locations. Methods Twelve females of 1 to 8 years old were studied by ultrasound imaging (Vevo 770, Visual Sonic, with a 20-60Hz mechanical probe) in search for morphological and functional abnormalities of arterial walls at the level of the aortic arch and the common carotids. Total thickness (TT), intima-media thickness (IMT) and extra-media thickness (EMT, [3]) were measured by a blinded, experienced investigator. Pulsatility was expressed as the percentage of variation between the diastolic and systolic diameters. Nine animals underwent blood sampling for LDL subfraction analysis using the Lipoprint system (Quantimetrix). Heart, aorta and carotids of three animals were kept in formol and processed for histology. Results Focal thickenings of carotid walls were observed on B-mode images in 5 out of 6 old animals (Fig. 1). Systematic proximal-wall measurements on M-mode images showed significantly higher carotid TT, IMT and EMT in aged vs young animals, along with decreased pulsatility (Fig. 2). LDL analysis and histology are in progress. Conclusions Using different US indexes of vessel wall functionality [3], we report in vivo evidence of atherogenesis in aged mouse lemurs. Therefore, this species holds promise as a new primate model of atherosclerosis

2006 2nd International Conference on Information & Communication Technologies

Good quality high resolution mouse cardiovascular MR images are obtained with gating using ECG. T... more Good quality high resolution mouse cardiovascular MR images are obtained with gating using ECG. The latter is affected by the hostile MR environment. It requires appropriate signal processing and correct QRS detection, but gating software methods are currently limited. Several hardware gating devices have already been proposed, each one was set to a determined MR static field intensity and ECG frequency bandwidth. This study sought to demonstrate the feasibility of digital real-time automatically updated gating method, able to perform high-resolution MR images of mouse hearts and aortic arches for different mouse strains, using different field intensities and ECG bandwidths. The real time acquisition chain consisted of ECG signal detection; digital signal processing and gating signal generation modeled using Simulink (The MathWorks Inc., Natick, MA)

Lecture Notes in Computer Science, 2003

Magnetic resonance perfusion imaging has become a technique of choice in the evaluation of patien... more Magnetic resonance perfusion imaging has become a technique of choice in the evaluation of patients with suspected coronary artery disease (CAD). In order to improve the quantification of perfusion parameters (such as signal intensity amplitude and upslope), an automatic registration technique is proposed. The results are compared to manually registered perfusion sequences. Perfusion maps computed from original and registered data

Ultrasound in Medicine & Biology, 2013

This work examines the use of lanthanide-based contrast agents and magnetic resonance imaging in ... more This work examines the use of lanthanide-based contrast agents and magnetic resonance imaging in monitoring liposomal behavior in vivo. Dysprosium (Dy) and gadolinium (Gd) chelates, Dydiethylenetriaminepentaacetic acid bismethylamide (Dy-DTPA-BMA) and Gd-DTPA-BMA, were encapsulated in pegylated distearoylphosphatidylethanolamine-based (saturated) liposomes, and then intravenously injected into Copenhagen rats with subcutaneous Dunning AT2 xenografts. Liposome-encapsulated Dy chelate shortens transverse relaxation times (T 2 and T 2 *) of tissue; thus, liposomal accumulation in the tumor can be monitored by observing the decrease in T 2 * relaxation time over time. The tumor was treated at the time of maximum liposomal accumulation (48 h) with confocal, cavitating high-intensity focused ultrasound to induce liposomal payload release. Using liposome-encapsulated Gd chelate at high enough concentrations and saturated liposomal phospholipids induces an exchange-limited longitudinal (T 1) relaxation when the liposomes are intact; when the liposomes are released, exchange limitation is relieved, thus allowing in vivo observation of payload release as a decrease in tumor T 1 .

Chinese medical journal, 2000

To assess the effects of Dy-DTPA-BMA (sprodiamide) on ex-vivo MR imaging of reperfused acute myoc... more To assess the effects of Dy-DTPA-BMA (sprodiamide) on ex-vivo MR imaging of reperfused acute myocardial infarction. Eighteen dogs were subjected to 2-hour coronary artery occlusion followed by 24-hour reperfusion. Dysprosium-chelate (Dy-DTPA-BMA) was injected into 16 dogs. Twenty minutes before their sacrifice. Two dogs did not receive the contrast medium and were used as controls. Excised hearts were imaged on T2-weighted spin-echo sequence (T2W SE) and T2*-weighted gradient recalled echo sequence (T2*W GRE), then sectioned and double-perfused for planimetric comparison. Dy-DTPA-BMA induced myocardial signal loss was detected on T2W SE and on T2*W GRE images. The signal loss was observed at the subendocardial location of the myocardial wall inducing an apparent enlargement of the left ventricle cavity and a thinning appearance of the anterior myocardial wall. Myocyte necrosis diminishes the potency of dysprosium to cause MR imaging signal intensity loss in reperfused myocardial inf...

Magma: Magnetic Resonance Materials in Physics, Biology, and Medicine, 2000

Magnetic Resonance in Medicine, 2003

Dynamic ventilation imaging using laser-polarized 3 He has a promising potential for elucidating ... more Dynamic ventilation imaging using laser-polarized 3 He has a promising potential for elucidating the physiology and physiopathology of the lungs. In this study, a methodological approach is proposed for the assessment and quantification of local ventilation parameters. High-temporal-resolution coronal ventilation image series were obtained with a projection-reconstruction (PR) sequence combined with the sliding-window technique. After image series were processed, parametric pixelby-pixel maps of the gas arrival time, filling time constant, inflation rate, and gas volume were generated. The acquisition technique and the signal processing procedure, which are referred to collectively as sliding pulmonary imaging for respiratory overview (SPIRO), were tested in vivo in healthy rat lungs using a contrast media injector for controlled 3 He flow and volume injection in the animal lungs. The same protocol was applied to broncho-constriction animal models using intravenous injection of methacholine solution. Inflation rate values measured in the lungs were found to decrease with increasing doses of injected methacholine solution. This study demonstrates that it is possible to obtain quantitative regional gas dynamic information using the SPIRO technique in a single polarized gas inspiration. Magn Reson Med 50:777-783, 2003.

Magnetic Resonance in Medicine, 2004

Vessel-wall measurements from multicontrast MRI provide information on plaque structure and evolu... more Vessel-wall measurements from multicontrast MRI provide information on plaque structure and evolution. This requires the extraction of numerous contours. In this work a contour-extraction method is proposed that uses an active contour model (NLSnake) adapted for a wide range of MR vascular images. This new method employs length normalization for the purpose of deformation computation and offers the advantages of simplified parameter tuning, fast convergence, and minimal user interaction. The model can be initialized far from the boundaries of the region to be segmented, even by only one pixel. The accuracy and reproducibility of NLSnake endoluminal contours were assessed on vascular phantom MR angiography (MRA) and high-resolution in vitro MR images of rabbit aorta. An in vivo evaluation was performed on rabbit and clinical data for both internal and external vessel-wall contours. In phantoms with 95% stenoses, NLSnake measured 94.3% ؎ 3.8%, and the accuracy was even better for milder stenoses. In the images of rabbit aorta, variability between NLSnake and experts was less than interobserver variability, while the maximum intravariability of NLSnake was equal to 1.25%. In conclusion, the NLSnake technique successfully quantified the vessel lumen in multicontrast MR images using constant parameters. Magn Reson Med 51:370-379, 2004.

Magnetic Resonance in Medicine, 1999

The assessment of both pulmonary perfusion and ventilation is of crucial importance for a proper ... more The assessment of both pulmonary perfusion and ventilation is of crucial importance for a proper diagnosis of some lung diseases such as pulmonary embolism. In this study, we demonstrate the feasibility of combined magnetic resonance imaging lung ventilation and perfusion performed serially in rat lungs. Lung ventilation function was assessed using hyperpolarized 3He, and lung perfusion proton imaging was demonstrated using contrast agent injection. Both imaging techniques have been implemented using projection-reconstruction sequences with free induction decay signal acquisitions. The study focused on fast three-dimensional (3D) data acquisition. The projection-reconstruction sequences used in this study allowed 3D data set acquisition in several minutes without high-performance gradients. 3D proton perfusion/helium ventilation imaging has been demonstrated on an experimental rat model of pulmonary embolism showing normal lung ventilation associated with lung perfusion defect. Assuming the possibility, still under investigation, of showing lung obstruction pathologies using 3He imaging, these combined perfusion/ventilation methods could play a significant clinical role in the future for diagnosis of several pulmonary diseases.

Journal of Magnetic Resonance Imaging, 1998

MR contrast media have been used to improve MR angiography (MRA). Their effect has been particula... more MR contrast media have been used to improve MR angiography (MRA). Their effect has been particularly beneficial for extracranial MRA. This study evaluated the efficacy of a new formulation of ultrasmall super‐paramagnetic iron oxide particles (USPIO) on three‐dimensional (3D) time of flight (TOF) MRA in the pelvis and lower limb circulation. Each of six dogs received 3 mg/kg of USPIO and .2 mmol/kg of gadolinium‐dieth‐ylenetriamine pentaacetic acid (Gd‐DTPA) bis‐meth‐ylamide (BMA) by intravenous infusion on separate examinations. Precontrast and postcontrast 3D‐TOF MRA images of the lower extremities were acquired over the course of 45 minutes postinjection. Signal intensity (SI) was measured on axial views along the external iliac, femoral, and popliteal arteries. USPIO provided clear demarcation of the major primary, secondary, and tertiary vessels and the improved contrast‐to‐noise ratio (CNR) was maintained for 45 minutes. Gd‐DTPA‐BMA provided less signal enhancement than USPIO....

Investigative Radiology, 2003

To develop a simple and robust helium3 polarization system dedicated to small animal imaging. To ... more To develop a simple and robust helium3 polarization system dedicated to small animal imaging. To demonstrate the potential of helium3 imaging for pulmonary ventilation and perfusion studies. A home-built polarization system based on spin-exchange technique was used. This system was applied for magnetic resonance imaging ventilation studies on rats using a 2-T magnet. Projection-reconstruction sequences combined with the sliding-window technique were used for acquisition of high temporal resolution ventilation images. Helium3 polarization levels up to 25% were obtained. Simultaneous ventilation and lung perfusion images were acquired with intravenous injection of superparamagnetic contrast agents. Dose effects were investigated using several contrast agent concentration values. A tabletop helium3 polarization system was realized. This equipment, which is easy to operate, allows the production of polarized gas appropriate to the requirements of small animal studies. This polarization system was used successfully on a ventilation/perfusion imaging study using intravascular contrast agent.

Investigative Radiology, 2000

To evaluate the use of two new blood pool contrast agents (P760, P775) compared with a low-molecu... more To evaluate the use of two new blood pool contrast agents (P760, P775) compared with a low-molecular-weight gadolinium chelate in MR angiography. The r1 efficiency of P760 was evaluated in vitro at 1.5 T; 3D abdominal contrast-enhanced MR angiography with qualitative analysis was compared in four rabbits after injection of incremental doses of P760 and in one rabbit after Gd-DOTA. A dynamic MR study was performed using a 2D T1-weighted turbo-flash MR sequence after injection of P760, P775, and Gd-DOTA. Each compound was tested at equivalent doses in three rabbits to assess r1 efficiency. Quantitative analysis of signal intensity in the aorta, the inferior vena cava, the renal cortex, and the medulla was performed. In vitro, the r1 efficiency of P760 was 23.3 mmol(-1) x L x sec(-1) at 1.5 T. Injection of a dose of P760 10 times less than Gd-DOTA allowed similar vessel visualization. The signal intensity peak and first-pass contrast kinetics in the aorta and the inferior vena cava were similar with the three products. Compared with P760 and Gd-DOTA, P775 allowed a greater renal cortex signal intensity at the first pass and a faster decrease on delayed images. The superior r1 efficiency of P760 and P775 was confirmed in vitro and in vivo at 1.5 T compared with Gd-DOTA, and P775 proved to be a rapid-clearance blood pool agent.

Investigative Radiology, 1994

Epilepsy Research, 2014

Background: MRI is routinely used in patients undergoing intracerebral electroencephalography (ic... more Background: MRI is routinely used in patients undergoing intracerebral electroencephalography (icEEG) in order to precisely locate the position of intracerebral electrodes. In contrast, fMRI has been considered unsafe due to suspected greater risk of radiofrequency-induced (RF) tissue heating at the vicinity of intracerebral electrodes. We determined the possible temperature change at the tip of such electrodes during fMRI sessions in phantom and animals.

Current Medical Research and Opinion, 2003

The dissociation of mechanical from non-mechanical energy utilisation can be studied using BDM (2... more The dissociation of mechanical from non-mechanical energy utilisation can be studied using BDM (2,3-butanedione monoxime), which inhibits the actin-myosin interaction without inhibiting Ca2+ transport. The objective of the present study was to establish if increasing the non-mechanical energy demand of perfused isolated pig hearts by dobutamine stimulation requires glycolysis with increased exogenous glucose uptake. Five isolated pig hearts (CTRL) were perfused for 90 min at constant flow (1 ml g(-1) min(-1)) with non-recirculating blood containing 30 mM BDM and 26 MBq/l of fluorine-18 2-fluoro-2-deoxyglucose (IFDG). This was compared with five hearts (DOBU) subjected to the same protocol for the first 30 min and then to dobutamine (1.5 microM) for the following 30 min and dobutamine (4 microM) for the last 30 min. Five other isolated hearts were perfused as for the DOBU group but without BDM (CTRLDOBU). Using a clinical PET scanner, glucose uptake was assessed by estimating 18FDG uptake using linear regression. The slope variations were compared using a global test of coincidence. Heart rate was at 100 +/- 2 b.p.m. in the CTRL group and at 180 +/- 7 b.p.m. in the DOBU group. 18FDG uptake was homogeneous within the whole myocardium and we observed a linear and regular increase in both the CTRL and DOBU groups (p, NS). In the CTRLDOBU group, 18FDG uptake was also homogeneous within the whole myocardium, but slopes of 18FDG uptake during dobutamine perfusion were higher than without dobutamine. In blood-perfused isolated pig hearts, exogenous glucose is not necessarily required when non-mechanical energy is increased by dobutamine stimulation. These findings suggest that ATP derived from glycolysis is not necessary to preserve myocardial Ca2+ transport during beta-adrenergic stimulation.

Contrast Media & Molecular Imaging, 2006