title: Effects of ET(A) receptor antagonism on proinflammatory gene expression and microcirculation following hepatic ischemia/reperfusion.
abstract: BACKGROUND
  The objective of this study was to investigate the effect of a specific endothelin(A) receptor antagonist (ET(A)-RA) on mRNA expression of genes encoding vasoactive mediators and proinflammatory cytokines and on the microhemodynamics (assessed by measurement of laser Doppler flow and tissue blood gases) following complete vascular exclusion of the porcine liver.
  
  
  METHODS
  Sixteen adult German landrace pigs were subjected to 120 min of warm hepatic ischemia by total vascular exclusion. To avoid portal congestion, a passive porto-femoro/jugular bypass was implanted. The animals were divided into 2 groups: the control group received saline solution and the therapy group was given the selective ET(A)-RA BSF 208075. Hepatic microcirculation was evaluated by p(O(2)) and p(CO(2)) measurement with the Paratrend sensor and by laser Doppler flow measurement. Liver tissue samples were collected 1 h after reperfusion and quantitative mRNA expression for prepro-ET-1, pro-IL-1beta, pro-IL-6, pro-TNF-alpha, eNOS was analyzed using the TaqMan system. Additionally, immunohistochemical analysis using a semiquantitative score for ET-1 was performed. Postischemic liver damage was monitored by measurement of liver enzymes and assessed by histological analysis using a semiquantitative scoring classification.
  
  
  RESULTS
  Partial oxygen pressure in the hepatic tissue and laser Doppler flow were significantly improved in the therapy group. One hour after reperfusion, quantitative RT-PCR revealed significantly lower expression of prepro-ET-1, eNOS, pro-TNF-alpha, and pro-IL-6 in the therapy group compared to controls. Immunohistochemical analysis demonstrated significantly reduced ET-1 immunostaining after therapy. Furthermore, blockade of ET(A) receptors prevents tissue damage.
  
  
  CONCLUSIONS
  Treatment with the selective ET(A)-RA BSF 208075 has protective effects on microcirculation after 120 min liver ischemia and reperfusion. The authors were able to show that ET(A)-RA not only affects the expression of vasoactive genes, but also decreases gene expression of proinflammatory cytokines such as TNF-alpha and IL-6.
authors: Department of Abdominal, Transplantation and Vascular Surgery, Leipzig, Germany.
authors: Dirk
authors: D
authors: Uhlmann
authors: Gabor
authors: G
authors: Gäbel
authors: Stefan
authors: S
authors: Ludwig
authors: Barbara
authors: B
authors: Armann
authors: Jochen
authors: J
authors: Hess
authors: Uta-Carolin
authors: UC
authors: Pietsch
authors: Andrea
authors: A
authors: Tannapfel
authors: Martin
authors: M
authors: Fiedler
authors: Juergen
authors: J
authors: Kratzsch
authors: Johann
authors: J
authors: Hass
authors: Helmut
authors: H
authors: Witzigmann
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis; D065130:Endothelin A Receptor Antagonists; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000502:physiology; D007249:Inflammation / Q000235:genetics*; D008099:Liver / Q000098:blood supply* / Q000473:pathology; D008833:Microcirculation / Q000187:drug effects*; D023421:Models, Animal; D010100:Oxygen / Q000032:analysis; D010666:Phenylpropionates / Q000494:pharmacology; D020011:Protective Agents / Q000494:pharmacology; D011724:Pyridazines; D012333:RNA, Messenger / Q000032:analysis; D015427:Reperfusion Injury / Q000517:prevention & control*; D013552:Swine
chemical_list: D015415:Biomarkers; D065130:Endothelin A Receptor Antagonists; D010666:Phenylpropionates; D020011:Protective Agents; D011724:Pyridazines; D012333:RNA, Messenger; C467894:ambrisentan; D010100:Oxygen