Carbon monoxide poisoning leaves behind more than headaches and confusion. For many survivors, the heart bears a hidden burden—one that can persist long after the initial exposure. A study published July 2, 2026, in Molecular Medicine offers an unprecedented look at how hyperbaric oxygen therapy (HBOT) may protect cardiac tissue at the molecular level, revealing mechanisms that could reshape how clinicians approach post-exposure cardiac care.
The Silent Cardiac Toll of Carbon Monoxide
When carbon monoxide binds to hemoglobin, it forms carboxyhemoglobin, starving tissues of oxygen and triggering a cascade of oxidative stress. The heart, with its relentless metabolic demands, is particularly vulnerable. Previous research has documented reduced ejection fraction, arrhythmias, and even myocardial infarction following acute poisoning. Yet monitoring long-term cardiac sequelae has remained challenging, with reliable biomarkers largely absent from clinical practice.
The Taiwanese research team, led by investigators at Chi Mei Medical Center and National Cheng Kung University, approached this gap through an emerging lens: extracellular vesicles. These nanoscale membrane-bound particles, released by cells into circulation, carry proteins that reflect the molecular status of their tissues of origin. Cardiac-enriched extracellular vesicles, the researchers hypothesized, might serve as molecular messengers revealing the hidden damage CO inflicts on the heart—and whether HBOT truly reverses it.
Mapping the Cardiac Proteome After Poisoning
The researchers established a rat model of carbon monoxide poisoning, subjecting animals to controlled CO exposure with or without subsequent hyperbaric oxygen treatment. Cardiac function was assessed through echocardiography, while myocardial injury was evaluated using histological, ultrastructural, and biochemical analyses. The core innovation lay in isolating cardiac-enriched extracellular vesicles from ex vivo whole-heart perfusate and subjecting them to global proteomic profiling.
The findings were striking. Carbon monoxide poisoning induced significant cardiac dysfunction, evidenced by reduced ejection fraction and fractional shortening alongside clear histological myocardial injury. Hyperbaric oxygen therapy attenuated these abnormalities—but the proteomic data revealed far more than functional improvement.
Mitochondrial Dynamics Under Pressure
The cardiac extracellular vesicle proteome underwent substantial remodeling after CO exposure, with alterations concentrated in pathways governing mitochondrial dynamics, calcium signaling, and cardiac contractility. Specifically, the poisoning disrupted regulators of mitochondrial fusion and fission, including optic atrophy type 1 (Opa1) and mitochondrial fission protein 1 (FIS1). These proteins determine whether mitochondria merge into networks or fragment—a balance critical for cellular energy production and survival.
Ultrastructural analysis confirmed the proteomic signals. CO-exposed cardiac tissue showed disrupted mitochondrial cristae, the folded inner membranes where ATP synthesis occurs. Mitophagy-related proteins shifted, suggesting impaired quality control of damaged mitochondria. Pyroptosis-associated signaling emerged, indicating inflammatory cell death pathways had been activated. Hyperbaric oxygen therapy mitigated each of these abnormalities, restoring more normal mitochondrial architecture and protein profiles.
Calcium Handling and Contractile Function
Beyond mitochondria, the study identified disruption in calcium-handling proteins critical for cardiac contraction. The ryanodine receptor 2 (Ryr2), which releases calcium from the sarcoplasmic reticulum to trigger muscle contraction, showed CO-associated alterations. Phospholamban (Pln), which regulates calcium reuptake and cardiac relaxation, similarly shifted. These changes correlated with impaired contractile parameters measured through echocardiography.
Notably, these same proteins—Ryr2 and Pln—appeared in circulating extracellular vesicles derived from serum, exhibiting CO-associated changes consistent with cardiac tissue alterations. This finding suggests that blood-based extracellular vesicle analysis could eventually provide a non-invasive window into cardiac injury and treatment response, though the researchers emphasize that further validation is required before clinical translation.
Energy Metabolism and the Oxygen Paradox
The proteomic analysis extended to mitochondrial energy metabolism pathways. CO poisoning remodeled proteins related to ATP production, reflecting the heart’s struggle to maintain energy supply under hypoxic stress. Hyperbaric oxygen therapy, which delivers 100% oxygen at pressures typically 2.0 to 2.5 atmospheres absolute, appears to restore more normal energy metabolism—though the exact mechanisms by which pressurized oxygen reverses these molecular changes remain under investigation.
The study’s authors note that their findings provide “hypothesis-generating insight” rather than definitive clinical guidance. The observed alterations in mitochondrial dynamics, energy metabolism, and calcium handling suggest pathways that future research might target, but the translation from rat models to human patients requires substantial additional work.
The FDA Context: Established Indication, Real Risks
Carbon monoxide poisoning represents one of the FDA-cleared indications for hyperbaric oxygen therapy, alongside decompression sickness, certain non-healing wounds, and late radiation tissue injury. The agency’s position acknowledges that HBOT can accelerate CO elimination and may reduce neurological sequelae, though questions about optimal patient selection and treatment protocols persist.
However, the FDA has consistently emphasized that HBOT carries real risks that must be weighed against potential benefits. The August 2025 safety letter to healthcare providers highlighted fire hazards, oxygen toxicity, barotrauma, and the dangers of improper home use of hyperbaric devices. The therapy requires administration in accredited facilities with trained personnel—not the wellness centers or home chambers sometimes marketed for unproven indications.
From Molecular Insights to Clinical Practice
The Taiwanese study’s framework—using cardiac-enriched extracellular vesicles as discovery tools for blood-based biomarker development—could eventually enable more precise monitoring of cardiac recovery after CO poisoning. If validated in human studies, circulating extracellular vesicle proteomics might identify patients at highest risk for cardiac complications, guide treatment decisions, and track response to HBOT or other interventions.
For now, the research adds molecular depth to the clinical rationale for HBOT in CO poisoning. Beyond simply clearing carboxyhemoglobin faster than normobaric oxygen, hyperbaric oxygen appears to trigger protective responses at the mitochondrial and contractile protein level—mechanisms that may explain some of the therapy’s documented benefits for cardiac outcomes.
The study also underscores the complexity of CO poisoning as a systemic insult. The heart’s vulnerability extends beyond acute hypoxia to encompass persistent mitochondrial dysfunction, altered calcium handling, and inflammatory signaling. Addressing these molecular disruptions may require more nuanced approaches than simply normalizing carboxyhemoglobin levels—a perspective that aligns with growing recognition that some CO poisoning survivors experience long-term cardiovascular consequences.
Looking Forward
As hyperbaric medicine continues to evolve, studies like this one demonstrate how proteomic technologies can illuminate therapy mechanisms that remain invisible to traditional clinical assessments. The extracellular vesicle approach offers a template for investigating HBOT’s effects in other conditions, potentially accelerating the development of biomarkers that could personalize treatment selection and monitoring.
For patients recovering from carbon monoxide exposure, and for the clinicians managing their care, these molecular insights offer a reminder that HBOT’s benefits extend beyond the immediate elimination of toxin. The therapy appears to engage fundamental cellular repair mechanisms—findings that support its established role in CO poisoning while highlighting the importance of maintaining access to accredited hyperbaric facilities for this life-threatening emergency.
Sources
- Hsiung et al. — Cardiac extracellular vesicle proteomics identifies mitochondrial and contractile dysfunction in carbon monoxide poisoning and their reversal by hyperbaric oxygen therapy (Molecular Medicine, 2026)
- FDA — Hyperbaric Oxygen Therapy: Get the Facts
- FDA — Follow Instructions for Safe Use of HBOT Devices (2025 Safety Letter)