Introduction
We showed recently that both selective iNOS inhibition and the radical scavenger Tempol prevented live bacteria from causing key features of hemodynamic, microcirculatory and metabolic derangements in porcine sepsis [1,2]. Here we investigated the effects of combined selective iNOS inhibition (L-NIL) with a free radical scavenger (Tempol) on P. aeruginosa-induced endothelial and hemostatic stress.
Methods
Twelve hours after induction of sepsis with continuous i.v. P. aeruginosa, 16 pigs received either no drug (CONT, n = 8) or a combination of L-NIL + Tempol (COMB, n = 8). Before and 12, 18 and 24 hours after the start of P. aeruginosa, plasma levels of markers related to endothelial function (von Willebrand factor [vWf]), hypercoagulability (thrombin-antithrombin complexes [TAT]), oxidative stress (8-isoprostane) and inflammation (TNF-α) were assessed.
Results
See Table 1. Combined treatment prevented a sepsis-induced increase in plasma 8-isoprostane and substantially attenuated the gradual increase in TNF-α.
Table 1.
| Baseline | 12 hours | 18 hours | 24 hours | ||
| vWf (mU/g protein) | CONT | 8 | 15 | 22 | 25 |
| (7; 31) | (13; 48)‡ | (14; 57)‡ | (15; 99)‡ | ||
| COMB | 7 | 11 | 13 | 14 | |
| (7; 18) | (9; 14)‡ | (12; 14)‡§ | (10; 17)‡§ | ||
| TAT (μg/g protein) | CONT | 1 | 3 | 6 | 6 |
| (1; 3) | (1; 5) | (3; 13)‡ | (5; 14)‡ | ||
| COMB | 2 | 2 | 2 | 3 | |
| (1; 3) | (1; 3) | (1; 5)§ | (2; 5)§ | ||
Data presented as the median (interquartile range), P < 0.05. ‡ vs baseline;§ COMB vs CONT.
Conclusion
Live bacteria-induced sepsis resulted in endothelial activation/dysfunction associated with activated coagulation, which were markedly attenuated by the combined iNOS blockade and radical scavenging. Suppression of oxidative stress and excessive inflammation might contribute to these results.
Acknowledgements
Supported by research grants IGA MZ CR, ND6837-3/2001 and MSM 0021620819. MM was the recipient of a research fellowship from the Alexander von Humboldt Stiftung.