Microvascular Endothelial Glycocalyx Surface Layer Visualization and Quantification

As a primary interface between the blood and underlying vascular wall, the endothelial glycocalyx layer is common to all blood vessels and covers the luminal surface of all endothelial cells. The endothelial glycocalyx has important roles as a regulator of microvascular endothelial functions such as mechanotransduction, leukocyte adhesion, and microvascular permeability. Disruption of the molecular structure of the endothelial glycocalyx disturbs physiological, and hemodynamic processes associated with the microvascular wall leads to microvascular hyperpermeability. Studying the glycocalyx is challenging because cultured cells present aberrant glycocalyx structure and tissue fixation techniques lead to the degradation and loss of this fine and delicate layer. Therefore, studying the glycocalyx requires in vivo imaging of the microcirculation. Here we describe two techniques for direct imaging and assessment of the glycocalyx surface layer integrity using intravital microscopy (IVM), a method widely used in the study of the dynamic changes that occur in the microcirculation during inflammation or injury.