Glycocalyx in vivo measurement

Area of Science:

• Cardiovascular Science
• Microcirculation Research
• Biomedical Engineering

Background:

• The endothelial glycocalyx (EG) is crucial for microcirculation and implicated in microvascular diseases.
• Assessing EG's physiological role and clinical significance is advancing with new diagnostic methods.
• Current laboratory methods for EG damage assessment lack reliability due to rapid degradation product turnover.

Purpose of the Study:

• To highlight recent advances in endothelial glycocalyx assessment methods.
• To discuss the clinical significance of the endothelial glycocalyx in microvascular pathology.
• To introduce novel bedside techniques for evaluating endothelial glycocalyx integrity.

Main Methods:

• Laboratory analysis of EG degradation products (syndecan-1, heparan sulphate, hyaluronan sulphate) in plasma.
• In vivo video microscopy, specifically Side-stream Dark Field (SDF) imaging.
• Bedside assessment of sublingual microcirculation using SDF to measure the Perfused Boundary Region (PBR).

Main Results:

• Plasma markers of EG degradation are unreliable due to rapid turnover.
• Side-stream Dark Field imaging allows indirect assessment of EG thickness.
• The Perfused Boundary Region (PBR) measured by SDF reflects red blood cell penetration into the EG.

Conclusions:

• Endothelial glycocalyx assessment is crucial for understanding microvascular health and disease.
• Bedside in vivo microscopy offers a more reliable method for assessing EG integrity compared to plasma markers.
• The Perfused Boundary Region (PBR) shows promise as a clinical index for endothelial glycocalyx status.