Pyruvate improves cerebral metabolism during hemorrhagic shock

Pyruvate (PYR) improves cellular and organ function hypoxia and ischemia by stabilizing the reduced nicotinamide adenine dinucleotide redox state and cytosolic ATP phosphorylation potential. In this in vivo study, we evaluated the effects of intravenous pyruvate on neocortical function, indexes of the cytosolic redox state, cellular energy state, and ischemia during a prolonged (4 h) controlled arterial hemorrhage (40 mmHg) in swine. Thirty minutes after the onset of hemorrhagic shock, sodium PYR (n = 8) was infused (0.5 g x kg(-1) x h(-1)) to attain arterial levels of 5 mM. The volume and osmotic effects were matched with 10% NaCl [hypertonic saline (HTS)] (n = 8) or 0.9% NaCl [normal saline (NS)] (n = 8). During the hemorrhage protocol, the time to peak hemorrhage volume was significantly delayed in the PYR group compared with the HTS and NS groups (94 +/- 5 vs. 73 +/- 6 and 72 +/- 4 min, P < 0.05). In addition to the early onset of the decompensatory phase of hemorrhagic shock, the complete return of the hemorrhage volume during decompensatory shock resulted in the death of five and four animals, respectively, in the HTS and NS groups. In contrast, in the PYR group, reinfusion of the hemorrhage volume was slower and all animals survived the 4-h hemorrhage protocol. During hemorrhage, the PYR group also exhibited improved cerebral cortical metabolic and function status. PYR slowed and reduced the rise in neocortical microdialysis levels of adenosine, inosine, and hypoxanthine and delayed the loss of cerebral cortical biopsy ATP and phosphocreatine content. This improvement in energetic status was evident in the improved preservation of the electrocorticogram in the PYR group. PYR also prevented the eightfold increase in the excitotoxic amino acid glutamate observed in the HTS group. The findings show that PYR administered after the onset of hemorrhagic shock markedly improves cerebral metabolic and functional status for at least 4 h.