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PAF (Platelet Activating Factor)
This stack of confocal images illustrates platelet activating factor (PAF)-induced stress fiber formation in endothelial and perivascular cells in a venular microvessel undergone inflammation-induced microvessel wall remodeling. The vessel was fixed at the PAF-induced peak hydraulic conductivity and double labeled for F-actin (phalloidin, green) and nuclei (DRAQ5, red). Confocal images were collected on the X-Y plane through sequential optical sectioning from the bottom toward the center of the vessel with 0.2-mm vertical steps along the Z-axis. The long stress fibers with elongated nuclei in outer layer are from proliferated fibroblasts/myofibroblasts. Some migrating leukocytes are showed in the vessel wall. The pericyte actin formed short bundles and was different in appearance from fibroblasts. Endothelial stress fibers are located in the inner layer (vertically orientated). Some of the stress fibers appeared to have traversed the cell body connecting adjacent cells. These changes correlated with a ninefold higher permeability response to PAF than the normal vessel response. For details please see publication by Yuan D and He P. "Vascular remodeling alters adhesion protein and cytoskeleton reactions to inflammatory stimuli resulting in enhanced permeability increases in rat venules" J Appl Physiol. 113(7):1110-20, 2012.

Link to video: http://jap.physiology.org/content/113/7/1110/suppl/DC1




The ex vivo isolated skeletal microvessel preparation for investigation of vascular reactivity
Here is #2 for the media library

The isolated microvessel preparation is an ex vivo preparation that allows for examination of the different contributions of factors that control vessel diameter, and thus, perfusion resistance(1-5). This is a classic experimental preparation that was, in large measure, initially described by Uchida et al.(15) several decades ago. This initial description provided the basis for the techniques that was extensively modified and enhanced, primarily in the laboratory of Dr. Brian Duling at the University of Virginia(6-8), and we present a current approach. This preparation will specifically refer to the gracilis arteriole in a rat as the microvessel of choice, but the basic preparation can readily be applied to vessels isolated from nearly any other tissue or organ across species(9-13). Mechanical (i.e., dimensional) changes in the isolated microvessels can easily be evaluated in response to a broad array of physiological (e.g., hypoxia, intravascular pressure, or shear) or pharmacological challenges, and can provide insight into mechanistic elements comprising integrated responses in an intact, although ex vivo, tissue. The significance of this method is that it allows for facile manipulation of the influences on the integrated regulation of microvessel diameter, while also allowing for the control of many of the contributions from other sources, including intravascular pressure (myogenic), autonomic innervation, hemodynamic (e.g., shear stress), endothelial dependent or independent stimuli, hormonal, and parenchymal influences, to provide a partial list. J Vis Exp. 2012 Apr 28;(62). pii: 3674. doi: 10.3791/3674.

Link to video: http://www.jove.com/video/3674/the-ex-vivo-isolated-skeletal-microvessel-preparation-for