Dual NEP/ECE inhibition improves endothelial function in mesenteric resistance arteries of 32-week-old SHR

Pieter Lemkens, Leon J. A. Spijkers, Merlijn J. Meens, Jelly Nelissen, Ben Janssen, Stephan L. M. Peters, Paul M. H. Schiffers, Jo G. R. De Mey*

*Corresponding author for this work

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Abstract

Endothelin 1 (ET-1), a potent vasoconstrictor, pro-mitogenic and pro-inflammatory peptide, may promote development of endothelial dysfunction and arterial remodeling. ET-1 can be formed through cleavage of big-ET-1 by endothelin-converting enzyme (ECE) or neutral endopeptidase (NEP). We investigated whether chronic treatment with the novel dual NEP/ECE inhibitor SOL1 improves functional and structural properties of resistance-sized arteries of 32-week-old male spontaneously hypertensive rats (SHR). SHR received a chronic 4-week treatment with SOL1, losartan or hydralazine. We then compared effects of inhibition of NO synthase (NOS) (100 mu M L-NAME), blockade of ETA-and ETB-receptors (10 mu M bosentan) and stimulation of the endothelium with 0.001-10 mu M acetylcholine (ACh) in isolated third-order mesenteric resistance arteries. Losartan and hydralazine significantly lowered blood pressure. Losartan decreased the media-to-lumen ratio of resistance arteries. L-NAME (1) increased arterial contractile responses to K+ (5.9-40 mM) in the losartan, SOL1 and vehicle group and (2) increased the sensitivity to phenylephrine (PHE; 0.16-20 mu M) in the SOL1 group but not in the losartan, hydralazine and vehicle group. Relaxing responses to ACh in the absence or presence of L-NAME during contractions induced by either 10 mu M PHE or 40 mM K+ were not altered by any in vivo treatment. Acute treatment with bosentan did, however, significantly improve maximal relaxing responses involving endothelium-derived nitric oxide and -hyperpolarizing factors in the SOL1 group but not in the losartan, hydralazine or vehicle group. Thus, chronic inhibition of NEP/ECE improved basal endothelial function but did not alter blood pressure, resistance artery structure and stimulated endothelium-dependent relaxing responses in 32-week-old SHR.

Original languageEnglish
Pages (from-to)738-745
Number of pages8
JournalHypertension Research
Volume40
Issue number8
DOIs
Publication statusPublished - Aug 2017

Keywords

  • bosentan
  • EDHF
  • endothelin-1
  • losartan
  • NO
  • SPONTANEOUSLY HYPERTENSIVE-RATS
  • RECEPTOR ANTAGONIST LOSARTAN
  • GENE-RELATED PEPTIDE
  • VASCULAR STRUCTURE
  • CONVERTING ENZYME
  • BLOOD-PRESSURE
  • NITRIC-OXIDE
  • DEPENDENT CONTRACTIONS
  • HYPERPOLARIZING FACTOR
  • NEUTRAL ENDOPEPTIDASE

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