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Mouse Clinic

Managing PIs: P. Carmeliet, W. Robberecht, M. Mazzone

The VRC was amongst the first to generate knockout mice in the early 1990s and has, since then generated dozens of transgenic (disease) mouse models. Since more than 15 years, the VRC has invested substantial resources to develop “in house” a mouse clinic to phenotype these mouse models extensively, with the aspiration to use similar (but adapted) tools, assays and techniques as those commonly used in the clinic to diagnoze diseases in humans. Therefore, assays and techniques, initially only available for larger animal species, were miniaturized and adapted, and “mouse doctors” with microsurgical skills and expertise were trained. Over the years, the VRC has been pioneering the development and use of novel assays and models in neurovascular research. An overview of such assays is listed.

Angiogenesis & lymphangiogenesis

Angiogenesis is critical for normal development but also contributes to the pathogenesis of numerous diseases.

Development

We routinely study vascular development in the embryo and placenta (whole mount immunostaining & in situ hybridization) and the postnatal retina and other organs (microvascular casting), and analyze the remodeling of the large thoracic vessels (intracardial angiography), the maintenance or regression of airway vessels. Vascular and lymhatic development is also routinely studied in zebrafish embryos and tadpoles (see Aquatic Facility).

Disease

Angiogenesis in pathological conditions is studied in available mouse models of cancer (ectopic or orthotopic implantation of syngeneic or xenograft tumors, spontaneously developing tumor models, hematogenic and lymphatic metastasis models), myocardial infarction (ligation of coronary artery), post-infarct myocardial hypertrophy, hindlimb ischemia (ligation of femoral artery), stroke (transient or permanent ligation of middle cerebral artery), eye disease (choroid neovascularization, retinal oxygen-induced vascular proliferation, cornea pocket neovascularization), skin wound healing (healthy and diabetic mice), bone fracture healing, matrigel plug neovascularization, inflammatory disease (models of rheumatoid arthritis, inflammatory bowel disease, atherosclerosis, restenosis), liver disease (cirrhosis) and others. To analyze the involvement of bone marrow derived cells, we perform total body irradiation, and transplant bone marrow cells, labeled with GFP or LacZ.

Assays are available to study various aspects of the structure and functionality of vessels, i.e. vascular permeability and leakage, perfusion (laser doppler, microspheres), drug delivery (HPLC analytical methods), tissue oxygenation (EPR oxymetry; hypoxia-probing), vessel organization (micro-CT), etc.
The functional consequences of therapeutic revascularization are analyzed by assaying cardiac and muscle performance using the following techniques and methods: hemodynamic measurements via echocardiography; (blood) pressure measurements via catheterization of high-fidelity micromanometers; exercise endurance testing (swimming or graded treadmill); cardiac electrophysiology (ECG); these assays can be performed in baseline conditions or after appropriate stress (physical exercise, cathecolamine stress, etc).

Neurobiology & Neurodegeneration

The following assays are available to study CNS development and disease.

Development

Navigation of anterior commissural axons across the midline (microdissection spinal cord; open book preparation); radial granule cell migration in the postnatally developing cerebellum (including electroporation of cerebellar slices).

Disease

Neuronal function is analyzed clinically by measuring motoric performance (accelerating rotarod; treadmill-wheel test, grid test, rotating axle test, footprint test, elevated plus maze test, diurnal spontaneous activity test, dynamometer grip test) and sensory nerve function (von frey cages, taxol test, hot plate test, tail re-drawal test). Nerve conduction is determined by EMG. Behaviour testing includes open field test, elevated plus maze test, passive avoidance test, contextual fear test, Morris water maze test, skinner box test, etc (collaboration with R. D’Hooghe). Other available mouse models include: (reversible or permanent) spinal cord ischemia, stroke, multiple sclerosis (EAE model), Parkinson disease and epilepsy (injection of neurotoxins PLP, MOG, 6-OHDA, MPTP, kainic acid), Alzheimer disease (APP transgenic lines), nerve regeneration (nerve crush models of sciatic or facialis nerve), retinal degeneration (light exposure). Muscle performance (fatiguability, recovery, relaxation, etc) is studied in isolated muscle preparations ex vivo.
Therapeutic concepts and strategies are evaluated by administration of compounds intracerebroventricularly (rats), intraperitoneally or intravenousl using osmotic minipumps, or via oral gavage. Plasmid delivery can be achieved by in vivo electroporation.

Metabolism

The following assays are available to study metabolism (in house or via local collaborations): measurements of metabolites in plasma and tissues (lactate, glycogen, FFA, ketone bodies, etc); 13C-NMR spectroscopy to measure glucose and fatty acid oxidation ex vivo; 31P-NMR spectroscopy to measure high energy phosphates (ATP, etc) in vivo; 1H-NMR spectroscopy to measure lactate and succinate ex vivo; EPR oxymetry to measure oxygen consumption; tracer studies to measure glycolysis, glucose and fatty acid oxidation in muscle preparations ex vivo; micro-PET measurements of glucose uptake; measurement of mitochondrial respiration in isolated mitochondria; etc.

Other models

A number of other mouse models are available: ischemia/reperfusion (in kidney, heart, liver and hindlimb); pulmonary hypertension (hypoxia chambers); muscle degeneration and regeneration (mdx model; cardiotoxin or glyceral injection); thrombosis and thrombolysis (pulmonary embolization via collagen-epinephrin injection, endothelial damage via Rose-Bengal injection, or stasis via ligation of inferior caval vein; pulmonary thrombolysis model; etc).

References: 
B. Oosthuyse et al. Deletion of the hypoxia-response element in the vascular endothelial growth factor promoter causes motor neuron degeneration. Nat Genet 28, 131-8 (2001)
S. Heymans et al. Inhibition of plasminogen activators or matrix metalloproteinases prevents cardiac rupture but impairs therapeutic angiogenesis and causes cardiac failure. Nat Med 5, 1135-42 (1999)
P. Carmeliet et al. Synergism between vascular endothelial growth factor and placental growth factor contributes to angiogenesis and plasma extravasation in pathological conditions. Nat Med 7, 575-83 (2001)
A. Luttun et al. Loss of placental growth factor protects mice against vascular permeability in pathological conditions. Biochem Biophys Res Commun 295, 428-34 (2002)
I. Stalmans et al. VEGF: a modifier of the del22q11 (DiGeorge) syndrome? Nat Med 9, 173-82 (2003)

Events

Karen Vousden, Paolo Sassone-Corsi, Christian Frezza, Nika Danial
12/09/2017 - 09:00