UT Southwestern Medical Center cardiologists have managed to induce the regeneration of heart muscle cells in mice by plunging the oxygen levels to well below normal.
Researchers with the Hamon Center for Regenerative Science and Medicine took some mice and created an atmosphere similar to what would be found at the top of Mount Everest. And then they waited. Two weeks later, the cells in their heart muscle began to divide and grow. The findings were published in the journal Nature, and build upon a bedrock that researchers first established in 2011.
The reduction in oxygen, the researchers found, leads to improved heart function and an increase in cardiomyocytes, or cardiac muscle cells. The doctors hope that this research can lead to improved heart function after a heart attack. Generally, newborn mammals can regenerate their hearts. Researchers equate it to how skin recovers after a cut. But as the heart bathes in oxygen-rich air, it loses that ability rapidly in the weeks immediately after birth.
And so the researchers decided to lower the oxygen that the mice breathed in. The researchers had to drop the oxygen level from the normal 21 percent all the way down to 7 percent to generate growth. Even at 10 percent, there was no regeneration.
“Though counterintuitive, we’ve shown that severely lowering oxygen exposure can sidestep damage to cells caused by oxygen and turn cell division back on, leading to heart regrowth,” said Dr. Hesham Sadek, the associate professor of internal medicine at the Hamon Center.
In addition to Sadek, Drs. Diana Canseco, Wataru Kimura, and Yuji Nakada shared in the discovery. The work was paid for by grants from the National Institutes of Health as well as an endowment from the Hamon Charitable Foundation.