title: A chronic model for intravital microscopic study of microcirculatory disorders and leukocyte/endothelial cell interaction during normotensive endotoxemia.
abstract: Sepsis-induced microvascular leukocyte/endothelial cell interaction may result in a deterioration of capillary perfusion that finally leads to septic organ dysfunction. The aim of the present study was to characterize a novel, sublethal, two-hit model of chronic systemic sepsis that allows the repeated analysis of microcirculation by intravital microscopy. In Syrian golden hamsters the effect of a single i.v. endotoxin (LPS, 2 mg/kg, E. coli) injection (SH-LPS group, n = 5 animals) vs. a double LPS injection (DH-LPS group, n = 6 animals) was analyzed. After monitoring baseline parameters (t1), measurements were performed at 30 min (t2), 3 h (t3), 8 h (t4), 24 h (t5), 48 h (t6), 56 h (t7) and 72 h (t8) (both groups) after initial LPS exposure. In DH-LPS animals, a second LPS injection (2 mg/kg) was given at t6 (48 h). Intravital fluorescence microscopy was performed in a dorsal skin fold chamber preparation and allowed determination of leukocyte-endothelial cell interaction (leukocyte rolling and sticking), and measurement of functional capillary density (FCD), which served as a measure of capillary perfusion. The first LPS injection comparably altered leukocyte/endothelial cell interaction and capillary perfusion in both groups (t1-t6, P > 0.05, MANOVA). Between t6 and t8 leukocyte adherence decreased in SH-LPS animals, whereas in DH-LPS animals adherence remained constantly elevated (SH-LPS: -53.0 +/- 6.2% between t6 and t8 vs. DH-LPS: -3 +/- 5; P < 0.05). The ongoing inflammatory response in DH-LPS animals was associated with a progressive deterioration of FCD, whereas FCD remained constant in SH-LPS animals (DH-LPS: -71.5 +/- 17% between t6 and t8 vs. SH-LPS: 3.0 +/- 13%; P < 0.05). In parallel, coagulatory parameters were found significantly altered only in DH-LPS animals but not in SH-LPS animals. We conclude that "double hit" LPS exposure is an appropriate model (i) to analyze repeatedly over time microcirculatory disorders under conditions of persistent endotoxemia-induced inflammatory response, and (ii) to prove the effectiveness of novel anti-inflammatory strategies.
authors.affiliation: Department of Surgery, Klinikum Grosshadern Ludwig-Maximilians University, Munich, Germany.
authors.forename: J N
authors.initials: JN
authors.lastname: Hoffmann
authors.forename: B
authors.initials: B
authors.lastname: Vollmar
authors.forename: D
authors.initials: D
authors.lastname: Inthorn
authors.forename: F W
authors.initials: FW
authors.lastname: Schildberg
authors.forename: M D
authors.initials: MD
authors.lastname: Menger
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D001794:Blood Pressure; D002196:Capillaries / Q000473:pathology; D002448:Cell Adhesion / Q000187:drug effects; D002908:Chronic Disease; D006224:Cricetinae; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000473:pathology*; D019446:Endotoxemia / Q000473:pathology* / Q000503:physiopathology*; D004927:Escherichia coli Infections / Q000473:pathology* / Q000503:physiopathology*; D006439:Hemodynamics; D007962:Leukocytes / Q000473:pathology*; D008070:Lipopolysaccharides / Q000378:metabolism / Q000494:pharmacology; D008647:Mesocricetus; D008833:Microcirculation / Q000503:physiopathology; D008856:Microscopy, Fluorescence / Q000379:methods; D018805:Sepsis / Q000150:complications / Q000503:physiopathology
chemical_list: D008070:Lipopolysaccharides