The recovery time course of the endothelial glycocalyx after enzymatic and cytokine degradation.

The glycocalyx surface layer on vascular endothelial cells is thought to be a dynamic extracellular matrix, which exhibits changes in thickness and composition in response to local conditions. Previous research has shown that enzymes degrade the glycocalyx, while inflammation causes shedding of the layer. While reconstitution experiments have been performed, the endogenous recovery time of the glycocalyx after degradation has not been addressed. Endothelium with a partially or completely degraded glycocalyx is at risk for increased exposure to blood‐borne free radicals, which, under chronic conditions, could in turn contribute to cardiovascular disease. It is therefore important to ascertain the time course of endogenous recovery of the glycocalyx after degradation. To track glycocalyx recovery, we use micro‐particle image velocimetry in cremaster‐muscle venules to estimate the hydrodynamically relevant thickness of the glycocalyx in mice that have previously been treated with an enzyme (through systemic tail‐vein injection) or an inflammatory cytokine (through scrotal injection). Mice are injected with either hyaluronidase, heparinase III, or TNF‐ α and the glycocalyx thickness is estimated after 1, 3, 5, and 7 days. Preliminary data indicate that it takes over five days for the endothelial glycocalyx to restore itself to its native dimensions of ~ 0.5 μ m. Supported by NIH grant R01 HL76499.