Inhibition of haem oxygenase activity increases leukocyte accumulation in the liver following limb ischaemia‐reperfusion in mice

Abstract

Although the consequences of trauma or infection are normally controlled at the site of injury, loss of local control may lead to a whole body response, which has been identified clinically as the systemic inflammatory response syndrome (SIRS). If this systemic inflammatory process involves whole body infection, the condition is termed sepsis. In its worst case, SIRS results in multiple organ dysfunction occurring in approximately 30 % of septic patients, in 24 % of patients suffering from pancreatitis, in over 30 % of trauma and in 40 % of burn patients (Beal & Cerra, 1994; Davies & Hagen, 1997).Liver injury and dysfunction occurring during SIRS has often been overshadowed by concerns regarding cardiac, renal and respiratory function. The fact that liver dysfunction plays a central role in remote injury during SIRS has been supported by studies identifying liver dysfunction as one of the major factors contributing to the mortality of surgical patients suffering from multiple organ dysfunction following infrarenal aortic reconstruction (Huber et al. 1995;Maziak et al. 1998). Currently, pharmacologic protocols and mechanical devices are available to support most vital organ functions but none exists for the liver. The role of haem oxygenase (HO) in the hepatic accumulation of leukocytes in mice during the initiation of remote organ injury following normotensive limb ischaemia-reperfusion (I-R) was investigated. Remote organ injury was initiated by 1 h bilateral hindlimb ischaemia followed by either 1 or 1.5 h reperfusion (I-R) in male C57BL/6 mice. Mice were randomly assigned to either sham (no I-R, n = 4), I-R (n = 4 for both time points), I-R plus chromium mesoporphyrin (CrMP, n = 4) to inhibit HO or I-R plus haemin (n = 4) to increase HO. Leukocyte accumulation and leukocyte-endothelial interaction were directly measured using fluorescence intravital microscopy. Leukocytes were labelled via an injection of rhodamine 6G. In sinusoids the total number and the number of stationary leukocytes were assessed. In postsinusoidal venules the number of adherent and rolling leukocytes and the velocities of both red blood cells and leukocytes were measured. The total number of leukocytes increased in sinusoids of I-R mice reaching a plateau within 1 h compared with sham animals, while the number of stationary leukocytes progressively increased over the entire study period. Stationary leukocytes in sinusoids increased after 1 and 1.5 h of I-R following CrMP, while they were significantly reduced following haemin treatment compared to animals treated with I-R only. In postsinusoidal venules a progressive increase in adherent leukocytes also occurred. As observed in sinusoids, CrMP significantly increased, while haemin significantly reduced leukocyte adhesion. The number of rolling leukocytes increased after CrMP in both I-R groups (1 and 1.5 h). The velocities of rolling leukocytes declined following 1.5 h of I-R compared with sham. Haemin treatment of 1.5 h I-R animals restored the velocities back to sham levels. The calcu...

Genetic overexpression of eNOS attenuates hepatic ischemia-reperfusion injury

“…Our data are congruent with existing findings regarding the actions of this enzyme during I-R. It has been reported that HO-1 activity within the liver decreases leukocyte interaction with the endothelium (38), possibly by suppressing the induction of adhesion molecules (36). HO-1 has also been reported to suppress inflammatory cytokine pathways involved in hepatic I-R injury (34).…”

Hindlimb Ischemia/Reperfusion-Induced Remote Injury to the Small Intestine: Role of Inducible Nitric-Oxide Synthase-Derived Nitric Oxide

“…Bilateral hindlimb I/R has been extensively used in our laboratory as a model of SIRS, which closely resembles the acute traumatic and ischemic insult seen in SIRS patients (Wunder et al, 2002). It has been demonstrated that hindlimb I/R causes cellular injury in remote organs (e.g., liver, lung, and intestine) and contributes to the development of MODS (Wunder et al, 2002;Yassin et al, 2002).…”

“…It has been demonstrated that hindlimb I/R causes cellular injury in remote organs (e.g., liver, lung, and intestine) and contributes to the development of MODS (Wunder et al, 2002;Yassin et al, 2002).…”

Hauptdeterminanten der Lebermikrozirkulation im Rahmen systemischer Entz�ndungsreaktionen

“…5). Eigene Untersuchungen an einem SIRS-Tiermodel (Ischämie/Reperfusion der Hinterläufe) zeigten, dass die Induktion der Hämoxygenase nicht nur das Ausmaß der Leberzellschädigung und Störung der Mikrozirkulation in den Sinusoiden reduziert, sondern auch die Adhäsion von Leukozyten in der Mikrozirkulation der Leber vermindert [65]. Das Zusammenspiel von CO und NO in der Steuerung der Mikrozirkulation der Leber ist komplex und weiterhin Gegenstand der aktuellen Forschung.…”