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Advisor(s)
Abstract(s)
O endotélio normal constitui uma barreira
física e biológica entre o sangue e a parede
vascular, que actua também como sensor e
transductor de diversos factores endógenos e
exógenos influentes na modulação da
circulação sanguínea. A função endotelial em
dado indivíduo e momento reflecte o equilíbrio entre factores de risco cardiovascular, predisposição genética e mecanismos vasculo-protectores. Nestes mecanismos tem acção predominante a disponibilidade e actividade do monóxido de óxido (NO) derivado do endotélio.
Adicionalmente, outras substâncias vasoactivas sintetizadas na parede vascular e/ou pelos elementos celulares do sangue também afectam o comportamento da interface sangueendotélio.
A vasomotricidade depende do equilíbrio entre substâncias vasodilatoras (em que se destaca a prostaciclina) e vasoconstritores (principalmente a endotelina-1 e, também, a angiotensina II). O equilíbrio coagulação-anticoagulação/fibrinólise é também afectado por diversos tipos de proteínas específicas. São analisados os principais mecanismos de acção dos factores indicados, de que depende a fluidez sanguínea em condições normais e na presença de endotélio intacto. É feita referência a potenciais anomalias, a analisar na parte II desta revisão.
Normal endothelium constitutes a physical and biological barrier between the blood and the vascular wall, and also acts as a sensor and transducer of various endogenous and exogenous factors that modulate the blood circulation. Endothelial activity in a given individual at any particular moment reflects the balance between cardiovascular risk factors, genetic predisposition and vascular protection mechanisms. The availability and activity of endothelium-derived nitric oxide (NO) is a major factor in these mechanisms. Further, vasoactive substances synthesized by the vascular wall and/or by blood cells may affect the behavior of the blood-endothelium interface. Vasomotricity is dependent on the balance between vasodilator substances (particularly prostacylin) and vasoconstrictor products (mainly endothelin-1 and angiotensin II). The coagulation-anticoagulation or fibrinolysis balance is also affected by various different proteins. The mechanisms of these factors, on which blood fluidity depends under normal conditions and with intact endothelium, are discussed, along with mention of potential abnormalities, which will be examined in the second part of this review.
Normal endothelium constitutes a physical and biological barrier between the blood and the vascular wall, and also acts as a sensor and transducer of various endogenous and exogenous factors that modulate the blood circulation. Endothelial activity in a given individual at any particular moment reflects the balance between cardiovascular risk factors, genetic predisposition and vascular protection mechanisms. The availability and activity of endothelium-derived nitric oxide (NO) is a major factor in these mechanisms. Further, vasoactive substances synthesized by the vascular wall and/or by blood cells may affect the behavior of the blood-endothelium interface. Vasomotricity is dependent on the balance between vasodilator substances (particularly prostacylin) and vasoconstrictor products (mainly endothelin-1 and angiotensin II). The coagulation-anticoagulation or fibrinolysis balance is also affected by various different proteins. The mechanisms of these factors, on which blood fluidity depends under normal conditions and with intact endothelium, are discussed, along with mention of potential abnormalities, which will be examined in the second part of this review.
Description
Copyright © 2006 Sociedade Portuguesa de Cardiologia. All rights reserved
Keywords
Endothelium Nitric oxide Endothelin-1 Prostacyclin Vasomotricity Coagulation
Pedagogical Context
Citation
Rev Port Cardiol 2006; 25 (11): 1061-1083
Publisher
Elsevier España