Using fluorescent micro-particle image velocimetry to examine the effects of chronic hyperglycemia on the endothelial surface layer in venules of NOD mice in vivo.

The existence of an endothelial surface layer (ESL) that selectively excludes macromolecules and retards plasma flow within 500 nm of the endothelium in microvessels of wild-type mouse is well established under normal physiologic conditions. Since all complications of type 1 and type 2 diabetes are derived from vascular disease arising from hyperglycemia, and since the ESL is situated as the first line of defense against vascular damage, we seek to establish the effects of hyperglycemia on the ESL. To test the effects of hyperglycemia on the ESL, we collected micro-particle image velocimetry (µ-PIV) data from post-capillary venules (20-50 µm diameter) in the cremaster muscle of non-obese diabetic (NOD) mice after chronic exposure to hyperglycemia and then again after regulation to euglycemic range with intraveneous insulin administration. Using microviscometric analysis of these µ-PIV data, fluid velocity profiles were inferred and used to estimate the hydrodynamically relevant thickness of the ESL. Before and after blood-glucose regulation with insulin. [ABSTRACT FROM AUTHOR]