The Endothelial Glycocalyx and Retinal Hemodynamics

Area of Science:

• Ophthalmology
• Vascular Biology
• Microcirculation

Background:

• The endothelial glycocalyx is vital for vascular resistance, thrombosis inhibition, and uniform blood flow.
• Its role in retinal hemodynamics and perfusion remains largely unexamined.

Purpose of the Study:

• To investigate the endothelial glycocalyx's role in regulating retinal hemodynamics and perfusion.
• To determine if glycocalyx degradation affects retinal thrombus formation.

Main Methods:

• Enzymatic degradation of the endothelial glycocalyx in mice using hyaluronidase and heparinase.
• Measurement of retinal vessel diameter, red blood cell (RBC) velocity, and distribution.
• Calculation of retinal blood flow, shear rates, and mean circulation time.
• Induction of retinal thrombosis using Rose Bengal dye and light.

Main Results:

• Glycocalyx degradation significantly increased arteriolar and venular diameters and retinal blood flow.
• Venular shear rate decreased, while retinal microhematocrit increased.
• Degradation of the glycocalyx enhanced the propensity for retinal thrombus formation.

Conclusions:

• Acute degradation of the endothelial glycocalyx significantly alters retinal hemodynamics.
• Changes include increased vessel diameter, blood flow, and microhematocrit.
• Glycocalyx removal leads to decreased venular shear rate and increased pro-thrombotic conditions.