From the Guidelines
The glycocalyx plays a vital role in mediating blood pressure and endothelial health by regulating vascular tone, preventing excessive fluid and protein leakage, and maintaining proper vascular permeability. The glycocalyx, a gel-like layer composed of glycoproteins, proteoglycans, and glycosaminoglycans, acts as a mechanosensor that detects changes in blood flow and shear stress, triggering the release of nitric oxide, which regulates vascular tone and blood pressure 1. Key functions of the glycocalyx include:
- Regulating adhesion of platelets and leukocytes to the endothelium
- Maintaining proper vascular permeability
- Preventing excessive leakage of fluid and proteins into tissues
- Serving as a binding site for anticoagulant factors like antithrombin III, helping prevent inappropriate blood clotting while maintaining normal blood flow and pressure. Damage to the glycocalyx, which can occur with hypertension, diabetes, inflammation, or oxidative stress, compromises these functions and contributes to endothelial dysfunction, increased blood pressure, and cardiovascular disease progression. Protecting glycocalyx integrity through lifestyle modifications, such as regular exercise and consuming antioxidant-rich foods, can help preserve endothelial function and blood pressure regulation. The importance of endothelial function in maintaining cardiovascular health is highlighted by studies such as the one published in the Journal of the American College of Cardiology 1, which provides guidelines for the ultrasound assessment of endothelial-dependent flow-mediated vasodilation of the brachial artery.
From the Research
Role of Glycocalyx in Mediating Blood Pressure and Endothelial Health
- The glycocalyx is a carbohydrate-rich layer that lines the luminal side of the vascular endothelium, playing an important role in maintaining endothelial layer integrity 2.
- Damage to the glycocalyx can precede further damage to the vascular endothelium and is associated with various conditions, including inflammation, trauma, and ischemia-reperfusion 2, 3.
- The endothelial glycocalyx is intimately linked to the homoeostatic functions of the endothelium, and its damage can lead to vascular pathology 3.
Factors Affecting Glycocalyx Integrity
- Hypervolaemia and hyperglycaemia can cause glycocalyx damage, while maintaining a physiological concentration of plasma protein, particularly albumin, can help prevent damage 3.
- Albumin is a major determinant of plasma colloid osmotic pressure and has protective endothelial effects, acting as a free radical scavenger and having immunomodulatory and anti-inflammatory effects 4.
- The (re)synthesis of hyaluronan, a main structural component of the glycocalyx, is dependent on the availability of its sugar substrates, linking glycocalyx biology directly to cellular glucose metabolism 5.
Relationship between Glycocalyx and Blood Pressure
- While there is no direct evidence linking glycocalyx integrity to blood pressure regulation in the provided studies, maintaining endothelial health is crucial for overall vascular function, which can impact blood pressure control.
- Angiotensin-converting enzyme (ACE) inhibitors, commonly used to treat hypertension, have been compared to angiotensin receptor blockers (ARBs) in terms of efficacy and adverse events, but the relationship between these medications and glycocalyx integrity is not explicitly discussed in the provided studies 6.