title: Autoregulation of portal circulation: a correlative study of circulation and vascular morphology.
abstract: To investigate the mechanism of portal circulation and the genesis of portal hypertension, an in vivo model was made to increase portal venous flow (PVF) by forming a bypass shunt between the femoral artery to the splenic venous branch in pigs and dogs via a regulatable pump. Using this model, an autoregulatory hemodynamics of the portal circulation and corresponding morphological changes of the intrahepatic vascular system were determined. Immediately after blood flow increase (100 mL/min) to the portal vein, PVF increased to the baseline level plus bypass shunt flow. But, PVF returned to the baseline level within 1 h for both animals. Portal venous resistance (PVR) at 1 h was significantly higher than the baseline level (P < 0.05). By histometric analysis of the cross-sectional area of the portal and hepatic venous branches (CSA-PV, CSA-HV) using the biopsized liver, CSA-HV at 1 h was 27.6% of the CSA-HV of the baseline level in dog, which showed narrowing and contractive changes of the hepatic venous branches, and CSA-PV at 1 h was 36.4% of the CSA-PV of the baseline level in pig, which showed narrowing and contractive changes of the portal venous branches. It is suggested that a tone of the intrahepatic vascular system has an important role in the portal autoregulatory hemodynamics.
authors.affiliation: Second Department of Pathology, Akita University School of Medicine, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nanjo
authors.forename: H
authors.initials: H
authors.lastname: Masuda
authors.forename: T
authors.initials: T
authors.lastname: Sato
authors.forename: K
authors.initials: K
authors.lastname: Kawamura
authors.forename: Y
authors.initials: Y
authors.lastname: Asanuma
authors.forename: K
authors.initials: K
authors.lastname: Koyama
mesh_terms: D000818:Animals; D001706:Biopsy; D001794:Blood Pressure; D004285:Dogs; D006439:Hemodynamics / Q000502:physiology; D006706:Homeostasis; D008099:Liver / Q000098:blood supply* / Q000473:pathology*; D008102:Liver Circulation / Q000502:physiology*; D008854:Microscopy, Electron; D013552:Swine; D014655:Vascular Resistance / Q000502:physiology*