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. 2019 Dec 1:93:71-77.
doi: 10.1016/j.niox.2019.09.003. Epub 2019 Sep 14.

Nitrite pharmacokinetics, safety and efficacy after experimental ventricular fibrillation cardiac arrest

Thomas Uray  1 , Philip E Empey  2 , Tomas Drabek  3 , Jason P Stezoski  4 , Keri Janesko-Feldman  5 , Travis Jackson  4 , Robert H Garman  6 , Francis Kim  7 , Patrick M Kochanek  4 , Cameron Dezfulian  8
Affiliations

Nitrite pharmacokinetics, safety and efficacy after experimental ventricular fibrillation cardiac arrest

Thomas Uray et al. Nitric Oxide. .

Abstract

Introduction: Besides therapeutic hypothermia or targeted temperature management no novel therapies have been developed to improve outcomes of patients after cardiac arrest (CA). Recent studies suggest that nitrite reduces neurological damage after asphyxial CA. Nitrite is also implicated as a new mediator of remote post conditioning produced by tourniquet inflation-deflation, which is under active investigation in CA. However, little is known about brain penetration or pharmacokinetics (PK). Therefore, to define the optimal use of this agent, studies on the PK of nitrite in experimental ventricular fibrillation (VF) are needed. We tested the hypothesis that nitrite administered after resuscitation from VF is detectable in cerebrospinal fluid (CSF), brain and other organ tissues, produces no adverse hemodynamic effects, and improves neurologic outcome in rats.

Methods: After return of spontaneous circulation (ROSC) of 5 min untreated VF, adult male Sprague-Dawley rats were given intravenous nitrite (8 μM, 0.13 mg/kg) or placebo as a 5 min infusion beginning at 5 min after CA. Additionally, sham groups with and without nitrite treatment were also studied. Whole blood nitrite levels were serially measured. After 15 min, CSF, brain, heart and liver tissue were collected. In a second series, using a randomized and blinded treatment protocol, rats were treated with nitrite or placebo after arrest. Neurological deficit scoring (NDS) was performed daily and eight days after resuscitation, fear conditioning testing (FCT) and brain histology were assessed.

Results: In an initial series of experiments, rats (n = 21) were randomized to 4 groups: VF-CPR and nitrite therapy (n = 6), VF-CPR and placebo therapy (n = 5), sham (n = 5), or sham plus nitrite therapy (n = 5). Whole blood nitrite levels increased during drug infusion to 57.14 ± 10.82 μM at 11 min post-resuscitation time (1 min after dose completion) in the VF nitrite group vs. 0.94 ± 0.58 μM in the VF placebo group (p < 0.001). There was a significant difference between the treatment and placebo groups in nitrite levels in blood between 7.5 and 15 min after CPR start and between groups with respect to nitrite levels in CSF, brain, heart and liver. In a second series (n = 25 including 5 shams), 19 out of 20 animals survived until day 8. However, NDS, FCT and brain histology did not show any statistically significant difference between groups.

Conclusions: Nitrite, administered early after ROSC from VF, was shown to cross the blood brain barrier after a 5 min VF cardiac arrest. We characterized the PK of intravenous nitrite administration after VF and were able to demonstrate nitrite safety in this feasibility study.

Keywords: Animals; Asphyxia; Cardiopulmonary resuscitation; Heart arrest; Laboratory; Ventricular fibrillation.

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Conflict of interest statement

Declarations of interest: Dr. Dezfulian is the principal investigator for an investigator initiated phase 2 randomized clinical trial of inhaled nitric oxide after out-of-hospital cardiac arrest () funded by Mallinckrodt Pharmaceuticals, Inc. Drs. Dezfulian, Empey and Kim are investigators in a phase 2 randomized clinical trial of nitrite after out-of-hospital cardiac arrest () funded by NHLBI.

Figures

Figure 1.
Figure 1.. Results of the tissue 15-minute model.
Nitrite levels in (A) CSF, (B) brain, (C) heart and (D) liver tissue homogenates. Data are shown as mean (± standard error). Numbers of rats per group are shown within each bar.
Figure 2.
Figure 2.. Pharmacokinetics (PK) of nitrite in blood.
(A) Whole blood nitrite levels 15 minutes after start of resuscitation from short term experiments (CSF and tissue harvest after 15 min). (B) Whole blood nitrite levels up to 60 minutes after start of resuscitation from 8-days survival experiments including best fit PK modeling (solid line is the mean and dashed line is the standard deviation).
Figure 3.
Figure 3.. Physiological and biochemical results of the 8-days survival model.
Sequential measurements of physiologic and biochemical variables where made at baseline (BL) and after defined times (in minutes) after return of spontaneous circulation (e.g. 5 = 5 min after ROSC). Over a total time period of 60 minutes during ICU phase, Nitrite (red circles, n=10) and placebo (green circles, n=9) treated animals showed no significant difference in (A) heart rate, (B) blood pressure, (C) arterial pH, (D) lactic acid, (E) paO2 and (F) paCO2. Data are shown as mean (± standard error). For better visualization, error bars are directed only in one direction, above for placebo (green) and below for Nitrite (red).
Figure 4.
Figure 4.. Outcomes from 8-days survival model after VF CA.
(A) Neurological deficit score at 24, 48 hours and 8 days after CPR, (B) CA1 neuronal survival in % 8 days after CPR and (C) fear conditioning freezing on day 2 showed no significant differences between nitrite (green bar, n=10) compared to placebo (red bar, n=9). Sham shown as blue bar, n=5. Data are shown as mean (± standard error).
See this image and copyright information in PMC

References

    1. Members WG, Roger VL, Go AS, Lloyd-Jones DM, Benjamin EJ, Berry JD, Borden WB, Bravata DM, Dai S, Ford ES, Fox CS, Fullerton HJ, Gillespie C, Hailpern SM, Heit JA, Howard VJ, Kissela BM, Kittner SJ, Lackland DT, Lichtman JH, Lisabeth LD, Makuc DM, Marcus GM, Marelli A, Matchar DB, Moy CS, Mozaffarian D, Mussolino ME, Nichol G, Paynter NP, Soliman EZ, Sorlie PD, Sotoodehnia N, Turan TN, Virani SS, Wong ND, Woo D, Turner MB, Heart Disease and Stroke Statistics—2012 Update: A Report From the American Heart Association, Circulation 125 (2012) e2–e220. - PMC - PubMed
    1. Bernard SA, Gray TW, Buist MD, Jones BM, Silvester W, Gutteridge G, Smith K, Treatment of Comatose Survivors of Out-of-Hospital Cardiac Arrest with Induced Hypothermia, New Engl J Med 2002, pp. 557–563. - PubMed
    1. T. Hypothermia after Cardiac Arrest Study Group, Mild Therapeutic Hypothermia to Improve the Neurologic Outcome after Cardiac Arrest, New Engl J Med 2002, pp. 549–556. - PubMed
    1. Nielsen N, Wetterslev J, Cronberg T, Erlinge D, Gasche Y, Hassager C, Horn J, Hovdenes J, Kjaergaard J, Kuiper M, Pellis T, Stammet P, Wanscher M, Wise MP, Åneman A, Al-Subaie N, Boesgaard S, Bro-Jeppesen J, Brunetti I, Bugge JF, Hingston CD, Juffermans NP, Koopmans M, Køber L, Langørgen J, Lilja G, Møller JE, Rundgren M, Rylander C, Smid O, Werer C, Winkel P, Friberg H, Targeted Temperature Management at 33°C versus 36°C after Cardiac Arrest, New England Journal of Medicine 369 (2013) 2197–2206. - PubMed
    1. Winther-Jensen M, Pellis T, Kuiper M, Koopmans M, Hassager C, Nielsen N, Wetterslev J, Cronberg T, Erlinge D, Friberg H, Gasche Y, Horn J, Hovdenes J, Stammet P, Wanscher M, Wise MP, Åneman A, Kjaergaard J, Mortality and neurological outcome in the elderly after target temperature management for out-of-hospital cardiac arrest, Resuscitation 91 (2015) 92–98. - PubMed

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