Assessment of Microvessel Permeability in Murine Atherosclerotic Vein Grafts Using Two-Photon Intravital Microscopy

Abstract

Plaque angiogenesis and plaque hemorrhage are major players in the destabilization and rupture of atherosclerotic lesions. As these are dynamic processes, imaging of plaque angiogenesis, especially the integrity or leakiness of angiogenic vessels, can be an extremely useful tool in the studies on atherosclerosis pathophysiology. Visualizing plaque microvessels in 3D would enable us to study the architecture and permeability of adventitial and intimal plaque microvessels in advanced atherosclerotic lesions. We hypothesized that a comparison of the vascular permeability between healthy continuous and fenestrated as well as diseased leaky microvessels, would allow us to evaluate plaque microvessel leakiness. We developed and validated a two photon intravital microscopy (2P-IVM) method to assess the leakiness of plaque microvessels in murine atherosclerosis-prone ApoE3*Leiden vein grafts based on the quantification of fluorescent-dextrans extravasation in real-time. We describe a novel 2P-IVM set up to study vessels in the neck region of living mice. We show that microvessels in vein graft lesions are in their pathological state more permeable in comparison with healthy continuous and fenestrated microvessels. This 2P-IVM method is a promising approach to assess plaque angiogenesis and leakiness. Moreover, this method is an important advancement to validate therapeutic angiogenic interventions in preclinical atherosclerosis models.

Phosphorylcholine Monoclonal Antibody Therapy Decreases Intraplaque Angiogenesis and Intraplaque Hemorrhage in Murine Vein Grafts

“…We observed a clear reduction in neovessel density upon PC-mAb. These neovessels are leaky [ 41 ] and can be therapeutically targeted by interference in pericyte coverage [ 29 , 30 ]. Interestingly, PC-mAb has a positive effect on IPH by improved vessel maturation which decreased leakage of erythrocytes in the plaques.…”

Cognitive Impairments, Neuroinflammation and Blood Brain Barrier Permeability in Mice Exposed to Chronic Sleep Fragmentation During the Daylight Period.

“…Under deep isoflurane anesthesia, 3-5 kDa dextran-FITC (10 mg/mL-Sigma-Aldrich, Mo,USA) suspended in PBS was injected intravenously in the mouse tail [61][62][63]. After 20 min, mice were euthanized with CO2, blood was collected and mice were then extensively perfused with PBSheparin-20U to wash out any residual blood from the cerebral circulation.…”

Endothelial Barrier Function and Leukocyte Transmigration in Atherosclerosis

“…Depending on the anatomical locations within the vascular tree, the endothelium can be relatively leaky (capillaries/venules) or not (arteries). In addition, depending on the organ-specific function of the endothelium, it can be continuous (e.g., brain) or fenestrated (e.g., kidney/glands), allowing for more or less extravasation respectively, depending on TJs and AJs [ 41 , 42 ]. Transit through fenestrated endothelium is limited to micro-molecules only and is controlled by e.g., blood flow, the basement membrane and glycocalyx [ 41 ].…”