Abstract 18666: A Carbon Monoxide (CO) Scavenging Agent Reverses CO-Induced Mitochondrial Inhibition in vitro and in vivo
Introduction: There are 50,000 cases of carbon monoxide (CO) poisoning per year in the United States alone. Even with current therapy, 1/3 of moderate-severely poisoned patients have cardiac dysfunction and increased long-term mortality. CO toxicity is mediated by: (1) CO binding to hemoglobin, decreasing global oxygen delivery and (2) CO binding to cytochrome c oxidase in the electron transport chain, inhibiting mitochondrial respiration. We have developed a recombinant neuroglobin (rNgb) that has a high affinity for CO and can chelate CO away from hemoglobin and cytochrome c oxidase.
Methods: We obtained left ventricle tissue homogenate from healthy rats. We measured mitochondrial respiration using a Clark-type oxygen electrode respirometry system. We added substrates (pyruvate, malate, adenosine diphosphate) to maximize tissue respiration until hypoxia. We then compared respiration rates after reoxygenation in tissue exposed to 99.9% CO gas, exposed to CO gas then treated with rNgb, treated with rNgb without CO exposure, and control. Separately, we exposed sedated, ventilated mice to 4.5 minutes of 30,000 parts per million CO. After poisoning, we infused either phosphate buffered saline (PBS) or rNgb. We immediately isolated heart tissue after the exposure experiment and measured maximal tissue respiration using the same respirometry system. We compared the respiration rate of poisoned mice (both groups) to sedated mice without CO exposure.
Results: Heart tissue respiration was inhibited by CO to 33.0% (+/- 5.9%) of the control rate. Control and rNgb without CO did not affect respiration. The addition of rNgb reversed CO-induced inhibition of respiration (P<0.0001 by two-way ANOVA for interaction of CO and rNgb). In CO-poisoned mice treated with PBS, respiration of heart tissue was 62.3% (+/- 7.5%) of sedated control mice (unpaired t-testing P=0.0148). Treatment with rNgb restored tissue respiration to the level of control mice (P=0.5478) and significantly higher than rates of mice treated with PBS (P=0.0366).
Conclusions: We have developed a CO scavenging agent (rNgb) that can reverse CO-induced cardiac mitochondrial respiration inhibition both in vitro and in vivo, and has the potential to become a novel approach to treating CO poisoning.
Author Disclosures: J.J. Rose: None. L. Wang: None. I. Azarov: None. Q. Xu: None. X.N. Huang: None. A. Belanger: None. Y. Wang: None. L. Guo: None. C. Lui: None. K.B. Ucer: None. C.F. McTiernan: None. C.P. O’Donnell: None. J. Tejero: None. D.B. Kim-Shapiro: None. S. Shiva: None. M.T. Gladwin: None.
- © 2016 by American Heart Association, Inc.