Tumor necrosis factor-induced mortality is reversed with cyclooxygenase inhibition.
OBJECTIVE
The authors hypothesized that TNF would induce eicosanoid synthesis, and a cyclooxygenase inhibitor would attenuate both eicosanoid synthesis and improve survival in an LD90 TNF-induced (150 ng/kg/i.v./5 min) mortality model.


BACKGROUND
Tumor necrosis factor is a cardinal mediator in sepsis; however, little is known about its effects on arachidonate metabolism.


METHODS
Conscious male rats with carotid arterial and jugular venous catheters were randomized for mortality: group I, TNF alone (150 kg/i.v./15 min, n = 30); group II, ibuprofen (30 mg/kg/i.v. at t = -20 and +240 min), plus TNF, (n = 28); and for hemodynamics, eicosanoid synthesis, blood gases: group III, TNF alone, (n = 8); group IV, ibuprofen + TNF (n = 8); group V, monoclonal antibody to TNF plus TNF (n = 8). Mortality was determined at 4-72 hr. Other parameters determined over 4 hours (0, 5, 60, 120, 240 min).


RESULTS
TNF stimulated synthesis of (a) TXB2 (71 +/- 30 pg/ml, mean +/- SE at base vs. 117 +/- 18 at 4 hr, p < 0.02); (b) PGE2 (70 +/- 6 pg/ml at base vs. 231 +/- 68 at 4 hr, p < 0.02); (c) 6PGF (52 +/- 6 pg/ml at base vs. 250 +/- 80 at 4 hr, p < 0.02). Ibuprofen significantly (p < 0.05) inhibited eicosanoid synthesis from TNF. TNF-induced mortality (87%, 26/30) was dramatically decreased with ibuprofen (11%, 3/28), at 4, 24, and 72 hr (p < 0.01). Monoclonal antibody to TNF prevented all abnormalities and had 100% survival. Hemodynamic events were similar in both groups, but metabolic acidosis was attenuated with ibuprofen.


CONCLUSIONS
TNF stimulates arachidonic acid metabolism in vivo. A cyclooxygenase inhibitor attenuates eicosanoid synthesis and dramatically improves survival. TNF appears to have different effect on tissues that synthesize certain eicosanoids. Hypotension from TNF is not mediated via the eicosanoids. TNF-induced mortality, like endotoxemia/sepsis may be mediated, in part, via arachidonic acid metabolites. These new findings support the notion that cyclooxygenase inhibitors may be used as adjunctive therapy in clinical sepsis.
Fletcher
J R
JR
Department of Surgery, University of South Alabama, College of Medicine, Mobile.
Collins
J N
JN
Graves
E D
ED
Luterman
A
A
Williams
M D
MD
Izenberg
S D
SD
Rodning
C B
CB
D015121:6-Ketoprostaglandin F1 alpha / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D000138:Acidosis / Q000097:blood; D000818:Animals; D000911:Antibodies, Monoclonal; D001639:Bicarbonates / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects; D002245:Carbon Dioxide / Q000097:blood; D002423:Cause of Death; D015232:Dinoprostone / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D015777:Eicosanoids / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D011464:Epoprostenol / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D007052:Ibuprofen / Q000494:pharmacology*; D008297:Male; D010100:Oxygen / Q000097:blood; D051381:Rats; D017207:Rats, Sprague-Dawley; D013929:Thromboxane B2 / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D014409:Tumor Necrosis Factor-alpha / Q000008:administration & dosage / Q000494:pharmacology*
D000911:Antibodies, Monoclonal; D001639:Bicarbonates; D015777:Eicosanoids; D014409:Tumor Necrosis Factor-alpha; D002245:Carbon Dioxide; D013929:Thromboxane B2; D015121:6-Ketoprostaglandin F1 alpha; D011464:Epoprostenol; D015232:Dinoprostone; D010100:Oxygen; D007052:Ibuprofen