NAD+ infusion shields swine lungs from injury after cardiac arrest and resuscitation
In a swine model, a single NAD+ infusion after resuscitation reduced lung injury and ferroptosis markers, possibly via the YAP/ACSL4 pathway.
Summary
Lung injury is a common and dangerous complication in people who survive cardiac arrest. Researchers tested whether NAD+, a central metabolic coenzyme, could protect the lungs in a swine model of cardiac arrest and CPR. Pigs received a one-hour intravenous NAD+ infusion (20 mg/kg) shortly after resuscitation. Compared with untreated resuscitated pigs, NAD+ improved lung injury measures: lower serum surfactant protein D, less extravascular lung water, lower pulmonary vascular permeability, and better oxygenation. At 24 hours, lung tissue showed less damage and less cell death. NAD+ also reversed markers of ferroptosis, an iron-dependent form of cell death, and restored YAP expression while lowering ACSL4. The findings are preclinical and based on small groups, but they suggest NAD+ could be a candidate for protecting the lungs after resuscitation.
Detailed Summary
Even when CPR restores a heartbeat, many cardiac arrest survivors go on to develop serious lung injury. Ischemia-reperfusion injury, chest compression trauma, and post-resuscitation inflammation all contribute. Up to half of CPR survivors may develop acute respiratory distress syndrome, and mortality from acute lung injury remains around 30-40%. NAD+ is a core coenzyme in energy metabolism and a substrate for enzymes governing cell survival, and it has shown benefit in other lung injury models such as sepsis and local ischemia-reperfusion. Its role after cardiac arrest had been little studied.
The researchers used 22 male domestic swine randomized to a Sham group (surgery only, n=6), a CPR group (n=8), and a CPR + NAD+ group (n=8). In the CPR groups, ventricular fibrillation was induced and left untreated for 10 minutes, followed by 6 minutes of guideline-based CPR with epinephrine and defibrillation. Five minutes after return of spontaneous circulation (ROSC), the NAD+ group received 20 mg/kg intravenously over one hour, while the other groups received saline. Personnel were blinded to group allocation. Animals were monitored for 4 hours and then observed to 24 hours, when lungs were harvested.
Six animals in each intervention group achieved ROSC. NAD+ improved lung injury indices versus CPR alone: serum surfactant protein D (SP-D) differed at multiple time points, lung tissue SP-D differed at 24 hours, and extravascular lung water index and pulmonary vascular permeability index differed at 4 hours. Oxygenation index also improved. Histology showed marked lung damage and more apoptosis (TUNEL staining) in both CPR groups versus Sham, and these changes were significantly attenuated by NAD+.
On the mechanistic side, CPR raised lung ferrous iron, malondialdehyde, 4-hydroxynonenal, reactive oxygen species, and ACSL4 expression, while lowering glutathione and YAP expression, a pattern consistent with ferroptosis. NAD+ significantly reversed these changes. The authors propose that NAD+ limits post-resuscitation lung injury by suppressing ferroptosis through the YAP/ACSL4 pathway.
Important caveats apply. This is a small, single-center, preclinical swine study with six resuscitated animals per treatment group, one dose and timing, and only a 24-hour horizon. The provided text was truncated before the full results tables, so detailed statistics and survival data could not be reviewed. The YAP/ACSL4 link appears to be based on changes in expression, and the text available does not describe pathway-specific inhibitor or knockdown experiments, so causation is not established. Human trials would be needed before any clinical use.
Key Findings
- NAD+ (20 mg/kg over 1 hour after ROSC) improved lung injury markers in swine: SP-D, extravascular lung water, vascular permeability, and oxygenation index.
- Lung histology and TUNEL staining showed less tissue damage and apoptosis at 24 hours with NAD+ than with CPR alone.
- NAD+ reversed ferroptosis signatures: lower Fe2+, MDA, 4-HNE, and ROS, and higher glutathione, versus untreated CPR animals.
- NAD+ restored lung YAP expression and reduced ACSL4, suggesting ferroptosis suppression via the YAP/ACSL4 pathway.
- Six of eight animals in each CPR group achieved ROSC, so analyses rest on small groups of six resuscitated pigs.
Methodology
Randomized, blinded preclinical study in 22 male large white swine (Sham n=6, CPR n=8, CPR+NAD+ n=8) using 10 minutes of untreated ventricular fibrillation followed by 6 minutes of CPR. NAD+ 20 mg/kg or saline was infused intravenously over 1 hour starting 5 minutes after ROSC. Lung function was tracked for 4 hours (PiCCO, blood gases, serum SP-D), and lung tissue at 24 hours was assessed by histology, TUNEL, ferroptosis assays, and Western blot.
Study Limitations
The study used small groups (six resuscitated animals per treatment arm), a single dose and timing, male animals only, and a 24-hour endpoint, with no long-term survival or functional outcomes evident in the available text. The YAP/ACSL4 mechanism appears correlative, with no pathway-specific interventions described, and the supplied full text was truncated before the detailed results. Findings from healthy young swine may not translate to older or comorbid human patients.
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