Vasodilator effects of endothelin-converting enzyme inhibition and endothelin ETA receptor blockade in chronic heart failure patients treated with ACE inhibitors.
BACKGROUND
The importance of endothelin-1 in chronic heart failure (CHF) is unclear. We therefore investigated the effects of endothelin-converting enzyme (ECE) inhibition and endothelin ETA receptor blockade in CHF patients treated with ACE inhibitors. We also compared the function of ETA and ETB receptors in healthy subjects and patients with CHF.


RESULTS
Locally active doses of study drugs were infused into the nondominant brachial artery while forearm blood flow (FBF was measured by venous occlusion plethysmography. In CHF patients (n = 10), phosphoramidon (a combined ECE and neutral endopeptidase inhibitor) and BQ-123 (an ETA receptor antagonist) increased FBF by 52 +/- 10% (P = .0006) and 31 +/- 6% (P = .002), respectively, and thiorphan (a selective neutral endopeptidase inhibitor) reduced FBF by 15 +/- 5% (P = .0007). Forearm vasoconstriction to endothelin-1 (an ETA and ETB receptor agonist) was significantly blunted in CHF patients compared with control subjects (both n = 10; CHF versus control subjects, P < .001), whereas vasoconstriction to sarafotoxin S6c (an ETB receptor agonist) was significantly enhanced in CHF patients compared with control subjects (both n = 10; CHF versus control subjects. P < .05).


CONCLUSIONS
ECE inhibitors and ETA receptor antagonists may be useful as vasodilator agents in CHF patients already receiving treatment with an ACE inhibitor. Both ETA and ETB receptors can mediate agonist-induced vasoconstriction in healthy subjects and patients with CHF, but further studies are required to clarify the contribution of each receptor subtype in mediating the effects of endogenous endothelin-1.
Medical Research Council Clinical Research Initiative in Heart Failure, University of Glasgow, Scotland, UK. m.love@biomed.gla.ac.uk
M P
MP
Love
W G
WG
Haynes
G A
GA
Gray
D J
DJ
Webb
J J
JJ
McMurray
D000368:Aged; D000704:Analysis of Variance; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D016282:Aspartic Acid Endopeptidases / Q000037:antagonists & inhibitors*; D001916:Brachial Artery / Q000187:drug effects* / Q000201:enzymology; D002908:Chronic Disease; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000494:pharmacology; D000072396:Endothelin-Converting Enzymes; D005260:Female; D006020:Glycopeptides / Q000494:pharmacology; D006333:Heart Failure / Q000188:drug therapy* / Q000201:enzymology; D006801:Humans; D008297:Male; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors; D008875:Middle Aged; D015260:Neprilysin / Q000037:antagonists & inhibitors; D010456:Peptides, Cyclic / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin / Q000819:agonists; D012039:Regional Blood Flow / Q000187:drug effects; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects* / Q000502:physiology; D014757:Viper Venoms / Q000494:pharmacology
D000806:Angiotensin-Converting Enzyme Inhibitors; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D006020:Glycopeptides; D010456:Peptides, Cyclic; D011480:Protease Inhibitors; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin; D014662:Vasoconstrictor Agents; D014757:Viper Venoms; C057354:sarafotoxins s6; D016282:Aspartic Acid Endopeptidases; D008666:Metalloendopeptidases; D015260:Neprilysin; D000072396:Endothelin-Converting Enzymes; C072247:cyclo(Trp-Asp-Pro-Val-Leu); C008890:phosphoramidon