Sudden cardiac arrest (CA) is one of the leading causes of death worldwide. Despite advances in cardiopulmonary resuscitation (CPR) methods, 60-80% of these arrests result in immediate death, and of the remaining, only about 5 percent are successfully resuscitated to the extent that they are returned to productive lives. The poor outcomes of patients, who initially achieve return of spontaneous circulation (ROSC) after CA are attributed to the post-CA syndrome. While therapeutic hypothermia (TH) has proven effective in clinical studies, no pharmacological agent is available to improve outcome from CA. A protective role for nitric oxide (NO) in ischemia and reperfusion (IR) injury has been suggested by a number of studies. Although originally developed as a selective pulmonary vasodilator, inhaled NO has been shown to have systemic effects in a variety of pre-clinical and clinical studies without causing systemic vasodilation. In preliminary studies that serve as the foundation of this research proposal, we found that breathing a low concentration of NO starting 1h after successful CPR for 23h markedly improves short-term (up to 10 days) neurological and cardiac outcomes and survival in mice after 7.5 min of CA followed by CPR. Of note, the salutary effect of inhaled NO on 10-day survival after CA/CPR was abolished in mice deficient in soluble guanylate cyclase (sGC), a NO receptor. Based on these exciting new observations, we hypothesize that breathing NO after successful CPR from CA improves long-term outcome via sGC-dependent signaling mechanisms. To address this hypothesis, we propose to determine the impact of NO inhalation on the long-term outcome (up to 4 weeks) after CA/CPR (Aim 1), to examine the role of sGC in the protective effects of inhaled NO on outcomes of CA/CPR (Aim 2), and to elucidate the cellular mechanisms responsible for the protective effects of inhaled NO on the long-term outcomes after CA/CPR (Aim 3). Because inhaled NO does not cause systemic hypotension, in contrast to systemic NO-donors, it is uniquely suited for the treatment of post-CA patients in whom blood pressure is often unstable. Successful completion of the proposed studies in small mammals would provide the mechanisms foundation for large animal studies examining the effects of inhaled NO in CA/CPR. Given the established safety profile of inhaled NO, we believe the proposed studies will enable rapid translation of this novel and non- invasive therapeutic strategy to improve outcomes in patients suffering from sudden CA and the post-CA syndrome.

Public Health Relevance

Despite advances in resuscitation techniques, fewer than 8% of the 300,000 adults who experience cardiac arrest (CA;also called sudden cardiac death) in the US each year survive to hospital discharge, and up to 60% of survivors have long lasting neurological deficits. Using a mouse model of CA and successful resuscitation, the principle investigators recently discovered that breathing low concentrations nitric oxide (NO) can markedly improve survival and reduce brain injury in mice. With insights gained during the course of the proposed studies, together with the proven safety of NO breathing (used to treat babies with low oxygen levels-blue babies), it is anticipated that this novel therapy will be rapidly applied to help patients who experience sudden cardiac death.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL110378-02
Application #
8449637
Study Section
Surgery, Anesthesiology and Trauma Study Section (SAT)
Program Officer
Sopko, George
Project Start
2012-04-01
Project End
2016-03-31
Budget Start
2013-04-01
Budget End
2014-03-31
Support Year
2
Fiscal Year
2013
Total Cost
$478,009
Indirect Cost
$191,145
Name
Massachusetts General Hospital
Department
Type
DUNS #
073130411
City
Boston
State
MA
Country
United States
Zip Code
02199
Kida, Kotaro; Ichinose, Fumito (2014) Preventing ischemic brain injury after sudden cardiac arrest using NO inhalation. Crit Care 18:212
Buys, Emmanuel; Sips, Patrick (2014) New insights into the role of soluble guanylate cyclase in blood pressure regulation. Curr Opin Nephrol Hypertens 23:135-42
Kida, Kotaro; Shirozu, Kazuhiro; Yu, Binglan et al. (2014) Beneficial effects of nitric oxide on outcomes after cardiac arrest and cardiopulmonary resuscitation in hypothermia-treated mice. Anesthesiology 120:880-9
Ichinose, Fumito (2013) Improving outcomes after cardiac arrest using NO inhalation. Trends Cardiovasc Med 23:52-8