Pulmonary Phototherapy to Treat Carbon Monoxide Poisoning in Rats

Abstract

Background Carbon monoxide (CO) poisoning is a common cause of poison-related mortality. CO binds to hemoglobin in the blood to form carboxyhemoglobin (COHb), impairing oxygen delivery to peripheral tissues. Current treatment of CO poisoned patients involves oxygen administration to rapidly remove CO and restore oxygen delivery. Light dissociates CO from COHb with high efficiency. Exposure of murine lungs to visible laser-generated light improved the CO elimination rate in vivo. The aims of this study were to apply pulmonary phototherapy to a larger animal model of CO poisoning, to test novel approaches to light delivery, and to examine the effect of chemiluminescence-generated light on the CO elimination rate. Methods Anesthetized and mechanically ventilated rats were poisoned with CO and subsequently treated with air or oxygen combined with or without pulmonary phototherapy delivered directly to the lungs of animals at thoracotomy, via intrapleural optical fibers or generated by a chemiluminescent reaction. Results Direct pulmonary phototherapy dissociated CO from COHb reducing COHb half-life by 38%. Early treatment with phototherapy in critically CO poisoned rats improved lactate clearance. Light delivered to the lungs of rats via intrapleural optical fibers increased the rate of CO elimination without requiring a thoracotomy, as demonstrated by a 16% reduction in COHb half-life. Light generated in the pleural spaces by a chemiluminescent reaction increased the rate of CO elimination in rats breathing oxygen, reducing the COHb half-life by 12%. Conclusions Successful application of pulmonary phototherapy in larger animals and humans may represent a significant advance in the treatment of CO poisoned patients.

Effects of intravascular laser phototherapy on delayed neurological sequelae after carbon monoxide intoxication as evaluated by brain perfusion imaging: A case report and review of the literature

“…First, the laser directly dissociates CO from the blood. In murine models, Zazzeron et al [ 22 , 23 ] found that direct illumination of the lungs could facilitate the dissociation of CO from hemoglobin, thus increasing the concentration of exhaled CO. This finding indicates that the laser beam is capable of counteracting dissolved CO in situations involving acute intoxication or occult exposure.…”

First trimester placental mesenchymal stem cells improve cardiac function of rat after myocardial infarction via enhanced neovascularization

“…For the generation of an MI model, 8-week-old male Wistar rats (n ¼ 45) were used. Rats weighing 250-280g were anaesthetized with intraperitoneal ketamine (100 mg/kg) and xylazine (10 mg/kg) [21,22], and a small incision was made in the fourth intercostal space. After that, the heart was then gently brought out through the window.…”

COVID-19 morbidity and mortality caused by endogenous carbon monoxide poisoning, with recommendations for testing and treatment

“…Red Light Therapy at wavelengths of 630 to 660nm (FDA approved but not for CO poisoning) a. releases CO from heme proteins b. works invasively inside lungs [Zazzeron 2017] or externally, with light against skin c. other applications included relieving muscle pain, cramps, rashes, cough, headaches, and sore throats 5.6 Sunbathing in natural or artificial light (the latter is FDA approved for treatment of hyperbilirubinemia) a. hastens excretion of free CO through skin; enhanced by ingesting riboflavin [Vreman 2009] b. increases vitamin D synthesis and, via UVc radiation, kills viruses on skin and other surfaces Mechanical ventilation combined with high flow or hyperbaric oxygen are not recommended because they are not effective for survivors of CO poisoning. In a series of 81 cases reported from Taiwan, 50.6% suffered bad outcomes, including 11% who died [Kao 2009].…”