Hemodynamic changes in splanchnic blood vessels in portal hypertension.
Portal hypertension (PHT) is associated with a hyperdynamic state characterized by a high cardiac output, increased total blood volume, and a decreased splanchnic vascular resistance. This splanchnic vasodilation is a result of an important increase in local and systemic vasodilators (nitric oxide, carbon monoxide, prostacyclin, endocannabinoids, and so on), the presence of a splanchnic vascular hyporesponsiveness toward vasoconstrictors, and the development of mesenteric angiogenesis. All these mechanisms will be discussed in this review. To decompress the portal circulation in PHT, portosystemic collaterals will develop. The presence of these portosystemic shunts are responsible for major complications of PHT, namely bleeding from gastrointestinal varices, encephalopathy, and sepsis. Until recently, it was accepted that the formation of collaterals was due to opening of preexisting vascular channels, however, recent data suggest also the role of vascular remodeling and angiogenesis. These points are also discussed in detail.
Colle
Isabelle
I
Department of Hepatology and Gastroenterology, Ghent University Hospital, Ghent, Belgium. isabelle.colle@ugent.be
Geerts
Anja M
AM
Van Steenkiste
Christophe
C
Van Vlierberghe
Hans
H
D000818:Animals; D001685:Biological Factors / Q000502:physiology; D063385:Cannabinoid Receptor Modulators / Q000502:physiology; D002248:Carbon Monoxide / Q000502:physiology; D003097:Collateral Circulation / Q000502:physiology; D011464:Epoprostenol / Q000502:physiology; D006439:Hemodynamics; D006801:Humans; D006975:Hypertension, Portal / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D008102:Liver Circulation / Q000502:physiology; D008955:Models, Cardiovascular; D009389:Neovascularization, Pathologic; D009569:Nitric Oxide / Q000502:physiology; D013152:Splanchnic Circulation / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000502:physiology; D014664:Vasodilation / Q000502:physiology
D001685:Biological Factors; D063385:Cannabinoid Receptor Modulators; D042461:Vascular Endothelial Growth Factor A; C067410:endothelium-dependent hyperpolarization factor; D009569:Nitric Oxide; D002248:Carbon Monoxide; D011464:Epoprostenol