title: Lipopolysaccharide enhanced renal vascular response to endothelin-1 through ETA overexpression in portal hypertensive rats.
abstract: OBJECTIVE
  Hypo-perfusion resulting from intense renal vasoconstriction is traditionally contributed to renal dysfunction in advanced liver disease, although cumulative studies demonstrated renal vasodilatation with impaired vascular contractility to endogenous vasoconstrictors in portal hypertension and compensated liver cirrhosis. The pathophysiology of altered renal hemodynamics remains unclear. This study, using a rat model of portal hypertension with superimposed endotoxemia, was designed to delineate the evolution of renal vascular reactivity and vaso-regulatory gene expression during liver disease progression.
  
  
  METHODS
  Rats were randomized into sham surgery (SHAM) or partial portal vein ligation (PVL). Endotoxemia was induced by intraperitoneal injection of lipopolysaccharide (LPS) on the seventh day following surgery. Isolated kidney perfusion was performed at 0.5 h or 5 h after LPS to evaluate renal vascular response to endothelin-1.
  
  
  RESULTS
  In contrast to impaired vascular contractility of SHAM rats, PVL rats displayed enhanced renal vascular reactivity to endothelin-1 at 5 h following endotoxemia. There were extensive upregulations of inducible nitric oxide synthase in kidney tissues of endotoxemic rats. The changes of renal endothelin receptor type A (ETA ) level paralleled with the changes of renal vascular reactivity in LPS-treated rats. Compared with SHAM rats, PVL rats showed increased renal ETA and phosphorylated extracellular-signal-regulated kinases 1/2 (p-ERK1/2) at 5 h after LPS.
  
  
  CONCLUSIONS
  LPS-induced systemic hypotension induces a paradoxical change of renal vascular response to endothelin-1 between SHAM and PVL rats. LPS-induced renal vascular hyperreactivity in PVL rats was associated with upregulation of renal ETA and subsequent activation of ERK1/2 signaling.
authors.affiliation: Division of General Medicine, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan; Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan.
authors.forename: Chiao-Lin
authors.initials: CL
authors.lastname: Chuang
authors.forename: Hui-Chun
authors.initials: HC
authors.lastname: Huang
authors.forename: Ching-Chih
authors.initials: CC
authors.lastname: Chang
authors.forename: Fa-Yauh
authors.initials: FY
authors.lastname: Lee
authors.forename: Jaw-Ching
authors.initials: JC
authors.lastname: Wu
authors.forename: Jing-Yi
authors.initials: JY
authors.lastname: Lee
authors.forename: Hsian-Guey
authors.initials: HG
authors.lastname: Hsieh
authors.forename: Shou-Dong
authors.initials: SD
authors.lastname: Lee
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D019332:Endothelin-1 / Q000502:physiology*; D005786:Gene Expression Regulation; D006975:Hypertension, Portal / Q000235:genetics* / Q000503:physiopathology*; D007668:Kidney / Q000098:blood supply*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000235:genetics / Q000502:physiology; D008297:Male; D017207:Rats, Sprague-Dawley; D044022:Receptor, Endothelin A / Q000235:genetics* / Q000502:physiology*; D015854:Up-Regulation; D014661:Vasoconstriction / Q000187:drug effects / Q000235:genetics* / Q000502:physiology*
chemical_list: D019332:Endothelin-1; D008070:Lipopolysaccharides; D044022:Receptor, Endothelin A
keywords: endothelin receptor type A; lipopolysaccharide; partial portal vein ligation; portal hypertension; renal vascular reactivity