ABSTRACT

The endothelium, a monolayer of endothelial cells, constitutes the inner cellular lining of the blood vessels (arteries, veins and capillaries) and the lymphatic system, and therefore is in direct contact with the blood/lymph and the circulating cells. The endothelium is a major player in the control of blood fluidity, platelet aggregation and vascular tone, a major actor in the regulation of immunology, inflammation and angiogenesis, and an important metabolizing and an endocrine organ. Endothelial cells controls vascular tone, and thereby blood flow, by synthesizing and releasing relaxing and contracting factors such as nitric oxide, metabolites of arachidonic acid via the cyclooxygenases, lipoxygenases and cytochrome P450 pathways, various peptides (endothelin, urotensin, CNP, adrenomedullin, etc.), adenosine, purines, reactive oxygen species and so on. Additionally, endothelial ectoenzymes are required steps in the generation of vasoactive hormones such as angiotensin II. An endothelial dysfunction linked to an imbalance in the synthesis and/or the release of these various endothelial factors may explain the initiation of cardiovascular pathologies (from hypertension to atherosclerosis) or their development and perpetuation.

Contents

• 1. Introduction
• 2. Multiple Functions of the Endothelial Cells
  • 2.1 HETEROGENEITY OF THE ENDOTHELIAL CELLS
  • 2.2 HEMOSTASIS, THROMBOSIS AND FIBRINOLYSIS
  • 2.3 VASCULAR PERMEABILITY
  • 2.4 LEUKOCYTE TRAFFICKING
  • 2.5 VASCULOGENESIS, ANGIOGENESIS AND ARTERIOGENESIS
  • 2.6 METABOLISM AND CATABOLISM
• 3. Calcium Signaling in Vascular Cells and Cell-to-Cell Communications
  • 3.1 REGULATION OF MEMBRANE POTENTIAL AND INTRACELLULAR CALCIUM CONCENTRATION
  • 3.2 CALCIUM SIGNALING
  • 3.3 CELL-TO-CELL COMMUNICATION AND VASCULAR FUNCTION
• 4. Endothelium-Dependent Regulation of Vascular Tone
  • 4.1 NITRIC OXIDE SYNTHASES
  • 4.2 OTHER GASEOUS MEDIATORS
  • 4.3 METABOLISM OF ARACHIDONIC ACID
  • 4.4 ENDOCANNABINOIDS AND OTHER LIPID MEDIATORS
  • 4.5 OTHER ENDOTHELIUM-DERIVED VASOACTIVE SUBSTANCES
• Conclusion
• References
• Author Biography