Low Oxygen Promotes Heart Regeneration
An international team of scientists has successfully regenerated heart muscle by placing adult mice in a low-oxygen environment.
Cardiologists with UT Southwestern Medical Center have been able to duplicate the regeneration process of the heart's muscle, by putting experimental mice in a crucial low-oxygen environment. Researchers from the Hamon Center for Regenerative Science and Medicine purposely lowered the oxygen level in these mice to 7%, about the same concentration level a person would experience at the top of Mount Everest.
After 14 days or two weeks of low oxygen exposure, the heart muscle cells (cardiomyocytes) were separating and dividing. Under normal circumstances, these muscle cells do not divide, especially in adult mammals.
The research results were published in a magazine called Nature. It took years of work that began with the finding that the hearts of newborn mammals can actually regenerate, just as the skin has the ability to heal itself after a cut or scratch. However, the ability of the cardiomyocytes to regenerate is quickly discarded as age and oxygen rich environments affect the heart cells, causing damage.
Following a heart attack, the human heart is not capable of repairing itself, and thus leaves a devastating impact on the heart. An associate professor of Internal Medicine, Dr. Hesham Sadek states that the severity of lowering oxygen levels can sidestep the damage done to cells, and turn the cell division process back on again, leading to a regeneration of the heart.
Researchers of a current study lowered oxygen normal level of 21% to 7%, over the course of a few weeks, and monitored the functions of the heart. The study showed that the reduction of oxygen leads to increased heart function and cardiomyocytes. Researchers initially attempted a 10% oxygen-induced environment, but that research was not effective in aiding the heart regrowth. To get the best results, the oxygen level had to be decreased to avoid cell damage.
This means that the oxygen levels should be extremely low, a condition referred to as hypoxia.
The conclusion of the study suggests that when the heart is exposed to oxygen levels as low as the ones found on Mount Everest, the chances of reversing heart diseases are extraordinary. The study showed a remarkable breakthrough for heart regeneration. It is also possible that regeneration of other organs could be in the making. Complications can occur in the body where temperatures are extremely low, but chances are favorable in a controlled setting.
Yuji Nakada, Diana C. Canseco, SuWannee Thet, Salim Abdisalaam, Aroumougame Asaithamby, Celio X Santos, Ajay Shah, Hua Zhang, James E. Faber, Michael T. Kinter, Luke I. Szweda, Chao Xing, Ralph Deberardinis, Orhan Oz, Zhigang Lu, Cheng Cheng Zhang, Wataru Kimura, Hesham A. Sadek. Hypoxia induces heart regeneration in adult mice. Nature, 2016; DOI: 10.1038/nature20173