in-vivo-quantitative-assessment-myocardial-structure-function

<em>In Vivo</em> Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography

The use of Micro-Computed Tomography (MicroCT) for in vivo studies of small animals as models of human disease has risen tremendously due to the fact that ...

a-multimodal-imaging-approach-based-on-micro-ct-fluorescence

A Multimodal Imaging Approach Based on Micro-CT and Fluorescence Molecular Tomography for Longitudinal Assessment of Bleomycin-Induced Lung Fibrosis in Mice

Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease characterized by the progressive and irreversible destruction of lung architecture, which ...

Erasmus MC, Rotterdam

Erasmus MC

Age-related loss of hearing and vision are two very common disabling conditions, but the underlying mechanisms are still poorly understood. Damage by reactive oxygen species and other reactive cellular metabolites, which in turn may damage macromolecules such as DNA, has been implicated in both processes. To investigate whether DNA damage can contribute to age-related hearing and vision loss, we investigated hearing and vision in Ercc1(δ/-) mutant mice, which are deficient in DNA repair of helix-distorting DNA lesions and interstrand DNA crosslinks. Ercc1(δ/-) mice showed a progressive, accelerated increase of hearing level thresholds over time, most likely arising from deteriorating cochlear function. Ercc1(δ/-) mutants also displayed a progressive decrease in contrast sensitivity followed by thinning of the outer nuclear layer of the eyeball. The strong parallels with normal ageing suggest that unrepaired DNA damage can induce age-related decline of the auditory and visual system.

Accelerated loss of hearing and vision in the DNA-repair deficient Ercc1(δ/-) mouse.

Increasing evidence supports a role for the angiotensin II-AT1-receptor axis in aneurysm development. Here, we studied whether counteracting this axis via stimulation of AT2 receptors is beneficial. Such stimulation occurs naturally during AT1-receptor blockade with losartan, but not during renin inhibition with aliskiren.

AT1-receptor blockade, but not renin inhibition, reduces aneurysm growth and cardiac failure in fibulin-4 mice.

In the treatment of neuroendocrine tumors (NETs), complete surgical removal of malignancy is generally desirable, because it offers curative results. Preoperative guidance with radiolabeled somatostatin analogs, commonly used for NET diagnosis and preoperative planning, is limited by its low resolution, with the risk that tumor margins and small metastases will be incompletely resected with subsequent recurrence. A single hybrid probe combining radiotracer and optical dye would enable high-resolution optical guidance, also during surgery. In the current study, the hybrid labeled somatostatin analog Cy5-DTPA-Tyr(3)-octreotate (DTPA is diethylene triamine pentaacetic acid) was synthesized and evaluated for its ability to specifically trace NET cells in vitro and in an animal model. The performance of the hybrid tracer was compared with that of octreotate with only radiolabel or only optical label.

Evaluation of a Fluorescent and Radiolabeled Hybrid Somatostatin Analog In Vitro and in Mice Bearing H69 Neuroendocrine Xenografts.

Wall shear stress (WSS) is involved in the pathophysiology of atherosclerosis. The correlation between WSS and atherosclerosis can be investigated over time using a WSS-manipulated atherosclerotic mouse model. To determine WSS in vivo, detailed 3D geometry of the vessel network is required. However, a protocol to reconstruct 3D murine vasculature using this animal model is lacking. In this project, we evaluated the adequacy of eXIA 160, a small animal contrast agent, for assessing murine vascular network on micro-CT. Also, a protocol was established for vessel geometry segmentation and WSS analysis.

Contrast-enhanced micro-CT imaging in murine carotid arteries: a new protocol for computing wall shear stress.

The intratracheal instillation of bleomycin in mice induces early damage to alveolar epithelial cells and development of inflammation followed by fibrotic tissue changes and represents the most widely used model of pulmonary fibrosis to investigate human IPF. Histopathology is the gold standard for assessing lung fibrosis in rodents, however it precludes repeated and longitudinal measurements of disease progression and does not provide information on spatial and temporal distribution of tissue damage. Here we investigated the use of the Micro-CT technique to allow the evaluation of disease onset and progression at different time-points in the mouse bleomycin model of lung fibrosis. Micro-CT was throughout coupled with histological analysis for the validation of the imaging results.

Longitudinal assessment of bleomycin-induced lung fibrosis by Micro-CT correlates with histological evaluation in mice.

Marfan syndrome (MFS) is a connective tissue disorder in which aortic rupture is the major cause of death. MFS patients with an aortic diameter below the advised limit for prophylactic surgery (<5 cm) may unexpectedly experience an aortic dissection or rupture, despite yearly monitoring. Hence, there is a clear need for improved prognostic markers to predict such aortic events. We hypothesize that elastin fragments play a causal role in aortic calcification in MFS, and that microcalcification serves as a marker for aortic disease severity. To address this hypothesis, we analysed MFS patient and mouse aortas. MFS patient aortic tissue showed enhanced microcalcification in areas with extensive elastic lamina fragmentation in the media. A causal relationship between medial injury and microcalcification was revealed by studies in vascular smooth muscle cells (SMCs); elastin peptides were shown to increase the activity of the calcification marker alkaline phosphatase (ALP) and reduce the expression of the calcification inhibitor matrix GLA protein in human SMCs. In murine Fbn1 MFS aortic SMCs, Alpl mRNA and activity were upregulated as compared with wild-type SMCs. The elastin peptide-induced ALP activity was prevented by incubation with lactose or a neuraminidase inhibitor, which inhibit the elastin receptor complex, and a mitogen-activated protein kinase kinase-1/2 inhibitor, indicating downstream involvement of extracellular signal-regulated kinase-1/2 (ERK1/2) phosphorylation. Histological analyses in MFS mice revealed macrocalcification in the aortic root, whereas the ascending aorta contained microcalcification, as identified with the near-infrared fluorescent bisphosphonate probe OsteoSense-800. Significantly, microcalcification correlated strongly with aortic diameter, distensibility, elastin breaks, and phosphorylated ERK1/2. In conclusion, microcalcification co-localizes with aortic elastin degradation in MFS aortas of humans and mice, where elastin-derived peptides induce a calcification process in SMCs via the elastin receptor complex and ERK1/2 activation. We propose microcalcification as a novel imaging marker to monitor local elastin degradation and thus predict aortic events in MFS patients. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Yanto Ridwan

Department of Genetics

Erasmus MC, Rotterdam

In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography

A Multimodal Imaging Approach Based on Micro-CT and Fluorescence Molecular Tomography for Longitudinal Assessment of Bleomycin-Induced Lung Fibrosis in Mice

Yanto Ridwan

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Genetics

Erasmus MC, Rotterdam

In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography

A Multimodal Imaging Approach Based on Micro-CT and Fluorescence Molecular Tomography for Longitudinal Assessment of Bleomycin-Induced Lung Fibrosis in Mice

Department of Genetics