Non-Smoking Seals Have More CO, Dive Deep

Carbon monoxide (symbol CO) a potential new treatment for human diseases, has been found in elephant seals at levels on a par with chronic cigarette smokers, according to resarch by scientists at Scripps Institution of Oceanography at UC San Diego.

With its imperceptible features, carbon monoxide is widely known as the “silent killer” due to its risks at lethal concentrations. Far less known is that carbon monoxide is produced naturally in small quantities in humans and animals, and in recent years medical researchers have evaluated the gas as a treatment for diabetes, heart attacks, sepsis, and other illnesses.

Now scientists at Scripps Institution of Oceanography at UC San Diego say they have furthered science’s understanding of carbon monoxide’s natural characteristics and limitations by studying the gas in one of the world’s best divers: the elephant seal.

Colorless and odorless, carbon monoxide (CO) is now monitored in many homes with inexpensive detectors. In human bodies, CO is produced naturally as a byproduct of the breakdown of hemoglobin—molecules responsible for transporting oxygen—inside red blood cells. Roughly one percent of the hemoglobin inside healthy human adults is linked with carbon monoxide, with elevated percentages for chronic cigarette smokers due to the absorption of CO through tobacco inhalation. Carbon monoxide binds to hemoglobin to form a compound called carboxyhemoglobin, a molecule which can no longer bind and transport oxygen in the blood.

As described in the May 14 issue of the Journal of Experimental Biology, Scripps graduate student Michael Tift, Scripps research physiologist Paul Ponganis, and Daniel Crocker of Sonoma State University sought to learn more about carbon monoxide levels in elephant seals, which have the highest blood volume of any mammal and are renowned for their extreme diving proficiency. Elephant seals and other highly efficient divers conserve oxygen by shutting off blood flow to peripheral areas of their body and conserving oxygen for vital organs such as the heart, brain, and lungs.

To their surprise, the researchers discovered that carbon monoxide is bound to 10 percent of the hemoglobin in adult elephant seals, or 10 times the amount found in healthy humans, and roughly comparable to someone who smokes 40 cigarettes per day.

“We found that the elephant seal is able to reach incredible depths, apparently with lots of carbon monoxide, so these results are helping us find answers for the rates at which you can expose organs and tissues to this gas,” said Tift. “The elephant seal is giving us the big picture of which concentrations of carbon monoxide might be the most beneficial.”

Scripps inform that the Office of Naval Research, the National Institutes of Health, and the National Science Foundation funded the research project.

Source: Scripps Institution of Oceanography at UC San Diego