Anti-c5a ameliorates coagulation/fibrinolytic protein changes in a rat model of sepsis

Abstract

Sepsis and trauma are the two most common causes of disseminated intravascular coagulation and multiple organ dysfunction syndrome. Both disseminated intravascular coagulation and the systemic inflammatory response syndrome often lead to multiple organ dysfunction syndrome. The current studies have evaluated the relationship between the anaphylatoxin, C5a, and changes in the coagulation/fibrinolytic systems during the cecal ligation and puncture (CLP) model of sepsis in rats. CLP animals treated with anti-C5a had a much improved number of survivors (63%) compared to rats treated with pre-immune IgG (31%). In CLP rats treated with pre-immune IgG there was clearly increased procoagulant activity with prolongation of the activated partial thromboplastin time and prothrombin time, reduced platelet counts, and increased levels of plasma fibrinogen. Evidence for thrombin formation was indicated by early consumption of factor VII:C, subsequent consumption of factors XI:C and IX:C and anti-thrombin and increased levels of the thrombin-anti-thrombin complex and D-dimer. Limited activation of fibrinolysis was indicated by reduced plasma levels of plasminogen and increased levels of tissue plasminogen activator and plasminogen activator inhibitor. Most of these parameters were reversed in CLP rats that had been treated with anti-C5a. Production of C5a during sepsis may directly or indirectly cause hemostatic defects that can be reduced by blockade of C5a.

Figure 1.

Effects of anti-C5a on survival rates in CLP rats. Animals received either 400 μg of pre-immune IgG (CLP + IgG) or 400 μg of anti-C5a IgG (CLP + anti-C5a) intravenously immediately after the procedure of CLP. Sham animals underwent laparotomy without CLP. The data are presented as percentage of survival (n = total number of animals in each group).

Figure 2.

Effects of anti-C5a or pre-immune IgG on APTT or PT in CLP rats. APTT (A) and PT (B) levels were measured in plasma collected from the various groups at 12, 24, or 36 hours after laparotomy. The data represent means ±SEM from seven or more individual animals at each time point.

Figure 3.

Effects of anti-C5a and pre-immune IgG on plasma platelet or fibrinogen levels in the indicated groups. Platelet counts were done in platelet-rich plasma (A) and plasma clottable fibrinogen levels (B) were measured in CLP rats and sham rats at 12, 24, or 36 hours after laparotomy. The data represent means ±SEM from six or more individual animals at each time point.

Figure 4.

Effects of anti-C5a and pre-immune IgG on coagulation factor VII:C (FVII) in CLP in rats. FVII levels were measured at 12, 24, or 36 hours after laparotomy. The data represent means ±SEM from seven or more individual animals.

Figure 5.

Effects of anti-C5a and pre-immune IgG on coagulation factors IX:C (FIX) and XI:C (FXI) in CLP in rats. FIX (A) and FXI (B) levels were measured at 12, 24, or 36 hours after laparotomy. The data represent means ±SEM from seven or more individual animals.

Figure 6.

Effects of anti-C5a and pre-immune IgG on plasma AT or plasminogen levels in CLP-induced sepsis. AT (A) and plasminogen plasma (B) activities were measured in the CLP groups and in the sham group at 12, 24, or 36 hours after laparotomy. The data represent means ±SEM from six or more individual animals at each time point.

Figure 7.

Effects of anti-C5a and pre-immune IgG on t-PA or PAI in CLP and sham rats. t-PA (A) and PAI (B) plasma activities were measured at 12, 24, and 36 hours after the operation. Data represent means ±SEM from six or more animals at each time point.

Figure 8.

Effects of anti-C5a and pre-immune IgG on plasma TAT complex or D-dimer levels in CLP and sham rats. TAT complex (A) and D-dimer (B) levels were measured at 12, 24, or 36 hours after laparotomy. The data represent means ±SEM from six or more animals at each time point.