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The study's objective was to determine the effects of the administration of combinations of C1 esterase inhibitor (C1-INH) with coagulation factor XIII (F XIII) and N-acetylcysteine (NAC) with tirilazad mesylate (TM) on leukocyte adherence and on intestinal functional capillary density during experimental endotoxemia in rats. In a prospective, randomized, controlled animal study, 40 male Wistar rats were divided into 4 groups. Group 1 (CON group) served as control group. Group 2 (LPS group), group 3 (C1-INH+F XIII group) and group 4 (NAC+TM group) received endotoxin infusions (10 mg/kg/h for 2 h). In C1-INH+F XIII group, 100 U/kg b.w. C1-INH and 50 U/kg b.w. F XIII were administered after the first 30 min of endotoxemia. In the NAC+TM group, 150 mg/kg b.w. N-acetylcysteine and 10 mg/kg b.w. Tirilazad mesylate were administered after 30 min of endotoxemia. Leukocyte adherence at venules of the intestinal submucosal layer and functional capillary density in the villi intestinales and in the longitudinal and circular muscle layers were estimated by intravital fluorescence microscopy (IVM). C1-INH+F XIII reduced the count of firmly adherent leukocytes that was increased after LPS administration in the V3 venules (CON group 69 (17-160)/mm2; LPS group 635 (556-814)/mm2; C1-INH+F XIII group 503 (337-646)/mm2). NAC+TM reduced the firmly adherent leukocytes in the V3 venules (NAC+TM group 403 (309-572)/mm2) and in the V1 venules (CON group 55 (16-131)/mm2; LPS group 368 (306-475)/mm2; NAC+TM group 270 (216-308)/mm2) as well. FCD was not impaired after LPS challenge and there was no influence of both combinations on the FCD. We conclude that both drug combinations can reduce the leukocyte adherence in a sepsis model in rats.

Introduction: The study's objective was to determine the effects of the administration of N-acetylcysteine (NAC) and of tirilazad mesylate (TM) on intestinal functional capillary density, mesenteric plasma extravasation, leukocyte adherence and on cytokine release during experimental endotoxemia in rats., Methods: In a prospective, randomized, controlled animal study, 80 male Wistar rats were examined in 2 test series. Both series were divided into 4 groups. Group 1 served as control group (CON group). Group 2 (LPS group), group 3 (NAC group) and group 4 (TM group) received endotoxin infusions (10 mg/kg over 2 h). In NAC group 150 mg/kg body weight NAC was administered after the first 30 minutes of endotoxemia intravenously. In TM group, 10 mg/kg body weight TM was administered after the first 30 minutes of endotoxemia intravenously. Animals of the series 1 underwent studies of leukocyte adherence on submucosal venular endothelium of the small bowel wall and intestinal functional capillary density (FCD) in the intestinal mucosa and the circular as well as the longitudinal muscle layer by intravital fluorescence microscopy (IVM). Plasma levels of interleukin 1beta (IL-1beta), interferone gamma (IFN-gamma) and soluble intercellular adhesion molecule1 (s-ICAM 1) as well as white blood cell count (WBC) were estimated. In the animals of the series 2 mesenteric plasma extravasation was determined by IVM and plasma levels of tumor necrosis factor alpha (TNF-alpha), IL-4, IL-6, IL-10 and malondialdehyde (MDA) were estimated., Results: After LPS administration, FCD in the villi intestinales was unchanged and in the longitudinal muscularis layer it was increased. There was no effect of NAC or TM administration on FCD.Although the plasma extravasation was not significantly influenced by LPS administration, TM administration resulted in a lower plasma extravasation in the TM group compared to the other groups. After endotoxin challenge, the firmly adherence of leukocytes to vascular endothelium as a parameter of leukocyte activation in endotoxemia was increased but NAC or TM administration had no influence on leukocyte adherence. The plasma levels of IL-1beta, IL-6, IL-10, TNF-alpha, IFN-gamma and sICAM-1 were increased in the endotoxemic groups (LPS group, NAC group and TM group) and the WBC was decreased compared to controls. IL-4 levels were unchanged during observation period. Plasma MDA levels were not influenced by LPS administration compared to controls. The administration of NAC resulted in lower sICAM-1 and MDA levels compared to the LPS group. The IL-1beta, IL-6, IL-10, TNF-alpha and IFN-gamma plasma levels were not influenced by NAC or TM administration., Conclusions: In this posttreatment sepsis model in rats, NAC administration resulted in lower sICAM-1 and MDA levels compared to the LPS treated animals. TM administration reduced the plasma extravasation in this model.

Background: N-acetylcysteine (NAC) has been shown to improve splanchnic blood flow in experimental studies. This report evaluates the effects of NAC on liver perfusion and lactate signal intensities in the liver tissue of septic shock patients using proton magnetic resonance imaging and spectroscopy. Furthermore, the monoethylglycinexylidide (MEGX) test was used to investigate hepatic function., Methods: Five septic shock patients received 150 mg/kg body weight NAC as an intravenous bolus injection over 15 min. Lidocaine was injected both prior to and following NAC administration in order to determine MEGX formation. Measurements (hemodynamics, oxygen transport-related variables, blood samples for lactate, liver-related markers) were performed 1 hour before and 1 hour after NAC injection. In addition to the proton magnetic resonance imaging patients received two proton magnetic resonance spectra, one prior to and one 30 min subsequent to the onset of the NAC infusion at a 1.5 Tesla clinical scanner, for measurement of liver perfusion and liver lactate signal intensity., Main Findings: Following NAC infusion, the lactate signal intensity in the liver tissue showed a median decrease of 89% (11-99%), there was a median increase in liver perfusion of 41% (-14 to 559%), and the MEGX serum concentration increased three times (1.52-5.91)., Conclusions: A decrease in the lactate signal intensity in the liver tissue and an increase in the MEGX serum concentration and in liver perfusion might indicate improved liver function as a result of NAC administration. Patients with compromised hepatosplanchnic function, such as patients with septic shock due to peritonitis, may therefore benefit from NAC therapy.