Altered peripheral vascular responses to exogenous and endogenous endothelin-1 in patients with well-compensated cirrhosis.
Plasma endothelin concentrations are elevated in cirrhosis and correlate with disease severity. This study assessed forearm vascular responses to exogenous endothelin-1 (ET-1), and evaluated the contribution of endogenous ET-1 to the maintenance of basal peripheral vascular tone in patients with well-compensated cirrhosis (n = 11) and matched healthy controls (n = 8). Bilateral forearm blood flow (FBF) was measured at baseline and following unilateral, subsystemic, intrabrachial artery infusions of ET-1 (2 and 6 pmol/min); BQ-123, a selective ET(A) receptor antagonist (3 and 10 nmol/min); and BQ-788, a selective ET(B) receptor antagonist (0.3 and 1 nmol/min) using venous occlusion plethysmography. Baseline systemic hemodynamics and plasma ET-1 and big ET-1 concentrations were measured using electrical bioimpedance and radioimmunoassay, respectively. Patients and controls had similar baseline FBF, systemic hemodynamics, and plasma ET-1 and big ET-1 concentrations. In both groups, ET-1 and BQ-788 caused significant vasoconstriction (P < .001) and BQ-123 caused significant vasodilatation (P < .001). Compared with controls, cirrhotic patients had attenuated ET-1 responses (P < .001), augmented BQ-123 responses (P < .001), and similar BQ-788 responses (P = .62). Despite normal systemic hemodynamics and plasma ET-1 concentrations, forearm vascular responses to exogenous ET-1 are reduced in cirrhotic patients. The augmented vasodilatation to BQ-123 in cirrhotic patients is consistent with a compensated vasodilated state, and a greater contribution of ET-1 to the maintenance of basal vascular tone acting through the ET(A) receptor.
Helmy
A
A
Liver Unit, Department of Medicine, University of Edinburgh, Western General Hospital, UK. a.h.salem@ed.ac.uk
Jalan
R
R
Newby
D E
DE
Johnston
N R
NR
Hayes
P C
PC
Webb
D J
DJ
D000959:Antihypertensive Agents / Q000494:pharmacology; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000097:blood / Q000494:pharmacology* / Q000502:physiology*; D016232:Endothelins / Q000097:blood; D005260:Female; D005542:Forearm / Q000098:blood supply*; D006439:Hemodynamics; D006801:Humans; D008103:Liver Cirrhosis / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009842:Oligopeptides / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D011498:Protein Precursors / Q000097:blood; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D012016:Reference Values; D014655:Vascular Resistance / Q000187:drug effects* / Q000502:physiology*
D000959:Antihypertensive Agents; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D016232:Endothelins; D009842:Oligopeptides; D010456:Peptides, Cyclic; D010880:Piperidines; D011498:Protein Precursors; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; C086539:BQ 788; C072247:cyclo(Trp-Asp-Pro-Val-Leu)