Endothelium and hemorheology.

Area of Science:

• Cardiovascular Physiology
• Endothelial Biology
• Hemodynamics

Background:

• Vascular endothelium plays a key role in regulating vascular tone, platelet aggregation, and red blood cell deformability.
• Hemorheological characteristics, such as blood viscosity, influence endothelial mediator release and vascular tone.
• Endothelial cells sense biochemical and physical stimuli, releasing nitric oxide and oxygen free radicals.

Purpose of the Study:

• To review the role of the vascular endothelium in maintaining vascular homeostasis.
• To discuss the relationship between hemorheological characteristics and endothelial function.
• To present and evaluate an alternative hypothesis for hyperviscosity in ischemic syndromes.

Main Methods:

• Literature review of studies on vascular endothelium and hemorheology.
• Analysis of evidence linking blood viscosity, shear stress, and endothelial activation.
• Discussion of animal data and cross-sectional human studies regarding hyperviscosity and ischemic syndromes.

Main Results:

• The endothelium modulates vascular tone and hemorheological properties.
• Changes in blood viscosity directly affect shear stress, a stimulus for endothelial activation.
• Animal data support the proposed hypothesis, but human study evidence is controversial.

Conclusions:

• Vascular endothelium and hemorheology are intricately linked in maintaining vascular homeostasis.
• Hyperviscosity's role in ischemic syndromes requires further investigation, particularly in human studies.
• The review highlights the need for more research to clarify the controversial evidence.