Dipeptidyl Peptidase 4/Midline-1 Axis Promotes T Lymphocyte Motility in Atherosclerosis.

T cells play a crucial role in atherosclerosis, with its infiltration preceding the formation of atheroma. However, how T-cell infiltration is regulated in atherosclerosis remains largely unknown. Here, this work demonstrates that dipeptidyl peptidase-4 (DPP4) is a novel regulator of T-cell motility in atherosclerosis.

Noncontrast Magnetic Resonance Angiography for the Diagnosis of Peripheral Vascular Disease.

Contrast-enhanced magnetic resonance angiography (MRA) provides excellent assessment of the peripheral arterial vasculature and is considered an important adjunctive diagnostic modality for the assessment of peripheral arterial disease. However, given the high prevalence of chronic kidney disease in patients with peripheral arterial disease, the association of gadolinium contrast media with nephrogenic systemic fibrosis, and recent concern with consequences of long-term deposition of gadolinium in the brain, there has been a renewed interest in noncontrast MRA approaches. Recent improvements in pulse sequences combined with instrumentation have facilitated the development of newer noncontrast MRA sequences that provide high spatial resolution, allowing the evaluation of distal (infrageniculate and pedal) vessels of importance in patients with critical limb ischemia.

Comparative Dose of Contrast-Enhanced Spectral Mammography (CESM), Digital Mammography, and Digital Breast Tomosynthesis.

Objective: The purpose of this study is to provide a more accurate estimation of the radiation dose of contrast-enhanced spectral mammography (CESM) relative to that of 2D digital mammography and tomosynthesis using phantom and patient data and an accepted dosimetry protocol that eliminates vendor-specific average glandular dose (AGD) estimates while including breast density.

Materials And Methods: Patient and phantom AGD estimation was performed using two vendors (system 1 and system 2) in five imaging modes, including 2D, 3D, and CESM imaging. Patient AGD was retrospectively estimated from 45 patients who underwent mammography with all imaging modes during 2012-2016.

A new method for CT dose estimation by determining patient water equivalent diameter from localizer radiographs: Geometric transformation and calibration methods using readily available phantoms.

Purpose: Water equivalent diameter (Dw) reflects patient's attenuation and is a sound descriptor of patient size, and is used to determine size-specific dose estimator from a CT examination. Calculating Dw from CT localizer radiographs makes it possible to utilize Dw before actual scans and minimizes truncation errors due to limited reconstructed fields of view. One obstacle preventing the user community from implementing this useful tool is the necessity to calibrate localizer pixel values so as to represent water equivalent attenuation.

Cardiopulmonary exercise testing in the MRI environment.

Maximal oxygen consumption ([Formula: see text]max) measured by cardiopulmonary exercise testing (CPX) is the gold standard for assessment of cardiorespiratory fitness. Likewise, cardiovascular magnetic resonance (CMR) is the gold standard for quantification of cardiac function. The combination of CPX and CMR may offer unique insights into cardiopulmonary pathophysiology; however, the MRI-compatible equipment needed to combine these tests has not been available to date.

Lipoicmethylenedioxyphenol Reduces Experimental Atherosclerosis through Activation of Nrf2 Signaling.

Objective: Oxidative stress is implicated in the pathogenesis of atherosclerosis, and Nrf2 is the transcriptional factor central in cellular antioxidant responses. In the present study, we investigate the effect of a dihydrolipoic acid derivative lipoicmethylenedioxyphenol (LMDP) on the progression of atherosclerosis and test whether its effect on atherosclerosis is mediated by Nrf2.

Methods And Results: Both magnetic resonance imaging (MRI) scanning and en face analysis reveal that 14 weeks of treatment with LMDP markedly reduced atherosclerotic burden in a rabbit balloon vascular injury model.

Reproducibility of thoracic and abdominal aortic wall measurements with three-dimensional, variable flip angle (SPACE) MRI.

Purpose: To evaluate the reproducibility and repeatability of high-resolution, isotropic thoracic and abdominal aortic wall measurements, and determine the implications they have on the number of subjects necessary for future clinical trials.

Materials And Methods: Using a T1-weighted three-dimensional MRI SPACE sequence, we evaluated the interobserver, intraobserver, and scan-rescan variability of isotropic thoracic and abdominal aortic wall measurements in 15 cardiovascular diseased patients and 6 normal volunteers. Main outcome analyses were intracorrelation coefficient (ICC), mean relative error (mRE), and sample size calculation at 80% power to be used to compare placebo group and treatment group means in future two-arm randomized clinical trials.

Non-rigid registration and KLT filter to improve SNR and CNR in GRE-EPI myocardial perfusion imaging.

The purpose of the study was to evaluate the effect of motion compensation by non-rigid registration combined with the Karhunen-Loeve Transform (KLT) filter on the signal to noise (SNR) and contrast-to-noise ratio (CNR) of hybrid gradient-echo echoplanar (GRE-EPI) first-pass myocardial perfusion imaging. Twenty one consecutive first-pass adenosine stress perfusion MR data sets interpreted positive for ischemia or infarction were processed by non-rigid Registration followed by KLT filtering. SNR and CNR were measured in abnormal and normal myocardium in unfiltered and KLT filtered images following non-rigid registration to compensate for respiratory and other motions.

Aliskiren effect on plaque progression in established atherosclerosis using high resolution 3D MRI (ALPINE): a double-blind placebo-controlled trial.

Background: The renin-angiotensin system is well recognized as a mediator of pathophysiological events in atherosclerosis. The benefits of renin inhibition in atherosclerosis, especially when used in combination with angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (ACEIs/ARBs) are currently not known. We hypothesized that treatment with the renin inhibitor aliskiren in patients with established cardiovascular disease will prevent the progression of atherosclerosis as determined by high-resolution magnetic resonance imaging (MRI) measurements of arterial wall volume in the thoracic and abdominal aortas of high-risk patients with preexisting cardiovascular disease.

Z-Group ketone chain transfer agents for RAFT polymer nanoparticle modification via hydrazone conjugation.

A ketal-containing trithiocarbonyl compound has been synthesized and characterized as a chain transfer agent (CTA) in Reversible Addition Fragmentation Transfer (RAFT) polymerization. The ketal functionality does not interfere with RAFT polymerization of acrylate monomers, which proceeds as previously reported to yield macro-CTA polymers and block co-polymers. Post-polymerization ketal cleavage revealed ketone functionality at the polar terminus of an amphiphilic block co-polymer.

Improved in vivo human carotid artery wall T₂ estimation.

T(2) quantification has been shown to noninvasively and accurately estimate tissue iron content in the liver and heart; applying this to thin-walled carotid arteries introduces a new challenge to the estimation process. With most imaging voxels in a vessel being along its boundaries, errors in parameter estimation may result from partial volume mixing and misregistration due to motion in addition to noise and other common error sources. To minimize these errors, we propose a novel technique to reliably estimate T(2) in thin regions of vessel wall.

Design and Rationale for the Study of Changes in Iron and Atherosclerosis Risk in Perimenopause.

This study seeks to investigate changes in iron homeostasis and carotid arteries in women at risk of atherosclerosis, addressing a relatively unexplored hypothesis explaining why women have a 5-10 year lag in initial atherosclerotic events. Recent evidence points to hepcidin, the key regulator of macrophage iron uptake and release, as a potential mediator of risk. Furthermore, iron catalyzes the generation of free radicals that oxidize cholesterol stimulating atheroma formation.

In vivo targeting of inflammation-associated myeloid-related protein 8/14 via gadolinium immunonanoparticles.

Objective: Myeloid-related protein (Mrp) 8/14 complex (is a highly expressed extracellularly secreted protein, implicated in atherosclerosis. In this study, we evaluated the feasibility of targeting Mrp in vivo through synthetic immuno-nanoprobes.

Methods And Results: Anti-Mrp-14 and nonspecific IgG-conjugated gadolinium nanoprobes (aMrp-) were synthesized and characterized.

Assessment of carotid stenosis using three-dimensional T2-weighted dark blood imaging: Initial experience.

Purpose: To evaluate the use of a T2-weighted SPACE sequence (T2w-SPACE) to assess carotid stenosis via several methods and compare its performance with contrast-enhanced magnetic resonance angiography (ceMRA).

Materials And Methods: Fifteen patients with carotid atherosclerosis underwent dark blood (DB)-MRI using a 3D turbo spin echo with variable flip angles sequence (T2w-SPACE) and ceMRA. Images were coregistered and evaluated by two observers.

Long-term dipeptidyl-peptidase 4 inhibition reduces atherosclerosis and inflammation via effects on monocyte recruitment and chemotaxis.

Background: Dipeptidyl-peptidase 4 (DPP-4) inhibitors are increasingly used to accomplish glycemic targets in patients with type II diabetes mellitus. Because DPP-4 is expressed in inflammatory cells, we hypothesized that its inhibition will exert favorable effects in atherosclerosis.

Methods And Results: Male LDLR(-/-) mice (6 weeks) were fed a high-fat diet or normal chow diet for 4 weeks and then randomized to vehicle or alogliptin, a high-affinity DPP-4 inhibitor (40 mg · kg(-1) · d(-1)), for 12 weeks.

Noncontrast MRA for the diagnosis of vascular diseases.

The association between gadolinium-based contrast agents and neprogenic systemic fibrosis has helped propel noncontrast angiography techniques to center stage in the MR evaluation of vascular disease, especially in individuals with intrinsic renal diseases. Although balanced steady-state free precession, phase contrast, and time-of-flight sequences are currently being revisited and improved, new noncontrast angiographic methods have been created and are under development: ECG-gated 3D partial-Fourier fast spin echo (FSE) and 3D variable flip angle FSE (SPACE). All of these are attempts to develop noncontrast methods that offer equal or superior vascular diagnosis as compared with contrast-enhanced MR angiography.

Concerted action of aldehyde dehydrogenases influences depot-specific fat formation.

Vitamin A metabolite retinoic acid (RA) regulates life-sustaining differentiation processes and metabolic homeostasis. The aldehyde dehydrogenase-1 (Aldh1) family of enzymes (Aldh1a1, a2, and a3) catalyzes RA production from retinaldehyde and thereby controls concentrations of this transcriptionally active metabolite. The hierarchy of Aldh1 functions in adipose tissue has not been elucidated.

Direct T2 quantification of myocardial edema in acute ischemic injury.

Objectives: To evaluate the utility of rapid, quantitative T2 mapping compared with conventional T2-weighted imaging in patients presenting with various forms of acute myocardial infarction.

Background: T2-weighted cardiac magnetic resonance (CMR) identifies myocardial edema before the onset of irreversible ischemic injury and has shown value in risk-stratifying patients with chest pain. Clinical acceptance of T2-weighted CMR has, however, been limited by well-known technical problems associated with existing techniques.

Post-interventional three-dimensional dark blood MRI in the adult with congenital heart disease.

Background: Investigate a novel three-dimensional (3D) turbo spin echo (TSE) magnetic resonance imaging (MRI) sequence to assess stented segments in adults with congenital heart disease (CHD) after transcatheter intervention.

Methods: Adults with CHD referred for computed tomography (CT) after transcatheter intervention underwent MR exam with a 3D respiratory gated TSE sequence. Data obtained at the time of the study included type of CHD, radiation dose, length of time between exams, and luminal diameters of stented segments from each exam.