The Human Microcirculation: Regulation of Flow and Beyond

Area of Science:

• Cardiovascular Science
• Physiology
• Microcirculation Research

Background:

• The microcirculation adjusts vascular tone for tissue oxygen needs.
• Endothelial cells release diverse compounds like nitric oxide (NO), reactive oxygen species (ROS), and arachidonic acid metabolites to modulate vascular tone.
• Animal models offer insights, but unique aspects of human microcirculation require focused review.

Purpose of the Study:

• To review unique aspects of human microcirculation.
• To propose a multimodal concept of vasculoparenchymal communication.
• To explore the role of endothelial mediators in health and disease, particularly cardiovascular events.

Main Methods:

• Review of existing literature on microcirculation and vasoregulation.
• Analysis of mechanisms of endothelial mediator release.
• Synthesis of data to propose a new paradigm of vasculoparenchymal communication.

Main Results:

• In health, endothelial NO mediates vasodilation, inhibiting inflammation and proliferation.
• In disease/stress, endothelial ROS mediate vasodilation but also drive parenchymal inflammation, leading to dysfunction, thrombosis, and fibrosis.
• Specific pathways for the stress-induced shift in vasodilation mediators are proposed.

Conclusions:

• Microvascular dysfunction is a significant predictor of cardiovascular events.
• The proposed paradigm of multimodal vasculoparenchymal communication may explain this link.
• Identifying these pathways could lead to new treatments and preventive strategies for cardiovascular diseases.