Interference of angiotensin II and enalapril with hepatic blood flow regulation

Author(s)

Pereira, Adriano J. ^[1] ; Jeger, Victor ^{[1, 2]} ; Fahrner, Rene ^[3] ; Djafarzadeh, Siamak ^[1] ; Lensch, Michael ^[1] ; Takala, Jukka ^[1] ; Jakob, Stephan M. ^[1]

Affiliation

^[1] Univ Bern, Inselspital, Univ Hosp, Dept Intens Care Med, CH-3010 Bern - Switzerland

^[2] Univ Bern, Grad Sch Cellular & Biomed Sci, Bern - Switzerland

^[3] Univ Bern, Inselspital, Univ Hosp, Dept Visceral Surg & Med, CH-3010 Bern - Switzerland

• Document type: Journal article
• Source: AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY; v. 307, n. 6, p. G655-G663, SEP 15 2014.
• Web of Science Citations: 5

Abstract

Acute reduction of portal vein blood flow (Qpv) increases hepatic arterial perfusion (Qha) {[}the hepatic arterial buffer response (HABR)]. Angiotensin II (AT-II) reduces Qpv, but its effect on HABR is not known. We explored interactions of AT-II and enalapril with hepatic blood flow regulation. Twenty healthy anesthetized pigs were randomized to receive AT-II (n = 8) from 5 to 61 ng/kg per min, enalapril (n = 8) from 3 to 24 mu g/kg per h, or saline (n = 4). HABR was assessed by occluding portal vein and expressed as 1) ratio between changes in Qha and Qpv, 2) hepatic arterial conductance (Cha). AT-II infusion increased mean arterial blood pressure from 74 (66-77) mmHg to 116 (109-130) mmHg (median, IQR; P < 0.0001) and decreased cardiac output, Qpv, and renal artery flow (-24%, -28% and -45%, respectively). The fraction of cardiac output of Qha, carotid, and femoral flows increased. With enalapril, blood pressure decreased, whereas cardiac output was maintained with flow redistribution favoring hepatic and renal arteries. In AT-II group, dQha/dQpv increased from 0.06 (0.03, 0.17) to 0.24 (0.13, 0.31) (P = 0.002), but Cha during acute portal vein occlusion decreased from 4.3 (1.6, 6.6) to 2.9 (1.2, 3.7) ml/mmHg (P = 0.003). Both variables remained unchanged in the enalapril group and in controls. AT-II infusion reduces portal flow in parallel with cardiac output and induces a dose-dependent redistribution of flow, favoring brain, hepatic artery, and peripheral tissues at the expense of renal perfusion. During HABR, AT-II decreases Cha but increases Qha compensation, likely as result of increased hepatic arterial perfusion pressure. Enalapril had no effect on HABR. (AU)

• FAPESP's process: 11/22188-6 - Effects of angiotensin and angiotensin-converting enzyme inhibition on hepatic, and renal perfusion, organ function, and on the hepatic arterial buffer response in septic and healthy animals
• Grantee: Adriano José Pereira
• Support Opportunities: Scholarships abroad - Research