title: Intraperitoneal LPS amplifies portal hypertension in rat liver fibrosis.
abstract: Recent studies have shown that the risk of variceal bleeding in patients with liver cirrhosis increases with infections such as spontaneous bacterial peritonitis (SBP). In this study, we hypothesized that pretreatment with intraperitoneal LPS may escalate portal hypertension. In fibrotic livers (4 weeks after bile duct ligation, BDL), the activation of Kupffer cells (KCs) by zymosan (150 microg/ml) in the isolated non-recirculating liver perfusion system resulted in a transient increase in portal perfusion pressure. Pretreatment with intraperitoneal LPS (1 mg/kg body weight (b.w.) for 3 h) increased basal portal perfusion pressure, and prolonged the zymosan-induced increase from transient to a long-lasting increase that was sustained until the end of the experiments in BDL but not in sham-operated animals. Pretreatment with gadolinium chloride (10 mg/kg b.w.), MK-886 (0.6 mg/kg b.w.), Ly171883 (20 microM) or BM 13.177 (20 microM) reduced the maximal and long-lasting pressure increase in BDL animals by approximately 50-60%. The change in portal perfusion pressure was paralleled by a long-lasting production of cysteinyl leukotriene (Cys-LT) and thromboxane (TX) after LPS pretreatment. However, the response to vasoconstrictors was not altered by intraperitoneal LPS. Western blot analyses showed an increased Toll-like receptor (TLR)4 and MyD88 expression after LPS pretreatment. In vivo experiments confirmed that intraperitoneal LPS increased basal portal pressure, and extended the portal pressure increase produced by intraportal zymosan or by LPS infusion. In conclusion, upregulation of TLR4 and MyD88 expression in fibrotic livers confers hypersensitivity to LPS. This may lead to escalation of portal hypertension by production of TX and Cys-LT after endotoxin-induced KC activation. Therefore, LT inhibitors may represent a promising treatment option in addition to early administration of antibiotics in SBP.
authors.affiliation: Department of Medicine II (Gastroenterology and Hepatology), Liver Center Munich, University of Munich-Grosshadern, Munich, Germany. christian.steib@med.uni-muenchen.de
authors.forename: Christian J
authors.initials: CJ
authors.lastname: Steib
authors.forename: Anna C
authors.initials: AC
authors.lastname: Hartmann
authors.forename: Christoph
authors.initials: C
authors.lastname: v Hesler
authors.forename: Andreas
authors.initials: A
authors.lastname: Benesic
authors.forename: Martin
authors.initials: M
authors.lastname: Hennenberg
authors.forename: Manfred
authors.initials: M
authors.lastname: Bilzer
authors.forename: Alexander L
authors.initials: AL
authors.lastname: Gerbes
mesh_terms: D000818:Animals; D003545:Cysteine / Q000378:metabolism; D006975:Hypertension, Portal / Q000209:etiology* / Q000378:metabolism; D007263:Infusions, Parenteral; D015289:Leukotrienes / Q000378:metabolism; D008070:Lipopolysaccharides / Q000008:administration & dosage*; D008103:Liver Cirrhosis / Q000150:complications*; D008297:Male; D053594:Myeloid Differentiation Factor 88 / Q000378:metabolism; D010538:Peritonitis / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology; D017082:Portal Pressure / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013929:Thromboxane B2 / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000378:metabolism
chemical_list: D015289:Leukotrienes; D008070:Lipopolysaccharides; C507781:Myd88 protein, rat; D053594:Myeloid Differentiation Factor 88; C495347:Tlr4 protein, rat; D051197:Toll-Like Receptor 4; C112381:cysteinyl-leukotriene; D013929:Thromboxane B2; D003545:Cysteine