Tumor necrosis factor-α inhibition reduces CXCL-8 levels but fails to prevent fibrin generation and does not improve outcome in a rabbit model of endotoxic shock

The effects of a monoclonal antibody (mAb) to tumor necrosis factor-α (TNF-α) were examined in a rabbit model of endotoxic shock. Intravenous administration of lipopolysaccharide (100 μg/kg/hr) for 6 hours (n = 11) increased TNF-α levels. Fibrinogen was partially consumed, and fibrin deposits were seen in kidney and lungs at 24 hours. Mortality at 24 hours was 64%. Levels of interleukin-8 (aka CXCL-8) were notably increased. Mean arterial pressure (MAP) and leukocyte counts decreased, whereas creatinine levels were enhanced. The anti-TNF-α mAb (20 mg/kg i.v. bolus + 5 mg/kg/h i.v. for the first 90 minutes) (n = 10) efficiently inhibited the TNF-activity. Rabbits exhibited lower CXCL-8 levels; MAP improved, the decrease in leukocyte counts was partially prevented and creatinine levels were lower, but fibrinogen, fibrin deposits in kidneys and lungs and mortality, 55%, were similar to the LPS group. Rabbits that did not survive exhibited lower fibrinogen levels, more fibrin in kidneys and lungs and higher CXCL-8 and creatinine levels than survivors, while there were no differences in TNF-α, MAP and leukocytes. Thus, the inhibition of TNF-α, although beneficial through lowering CXCL-8 levels, is not enough to improve the outcome, which could be partly due to the inability to prevent the fibrin deposits formation in kidneys and lungs. (J Lab Clin Med 2003;141:257-64)