Featured Research

from universities, journals, and other organizations

Oxygen diminishes heart's ability to regenerate, researchers discover

Date:
April 24, 2014
Source:
UT Southwestern Medical Center
Summary:
Scientific research previously discovered that the newborn animal heart can heal itself completely, whereas the adult heart lacks this ability. New research by the same team today has revealed why the heart loses its incredible regenerative capability in adulthood, and the answer is quite simple -- oxygen.

(l-r) Drs. Wataru Kimura, Hesham Sadek, and Bao Puente.
Credit: Image courtesy of UT Southwestern Medical Center

Scientific research at UT Southwestern Medical Center previously discovered that the newborn animal heart can heal itself completely, whereas the adult heart lacks this ability. New research by the same team today has revealed why the heart loses its incredible regenerative capability in adulthood, and the answer is quite simple -- oxygen.

Related Articles


Yes, oxygen. It is well-known that a major function of the heart is to circulate oxygen-rich blood throughout the body. But at the same time, oxygen is a highly reactive, nonmetallic element and oxidizing agent that readily forms toxic substances with many other compounds. This latter property has now been found to underlie the loss of regenerative capacity in the adult heart.

This groundbreaking new finding, published in today's issue of Cell, finds that the oxygen-rich postnatal environment results in cell cycle arrest of cardiomyocytes, or heart cells.

"Knowing the key mechanism that turns the heart's regenerative capacity off in newborns tells us how we might discover methods to reawaken that capacity in the adult mammalian heart," said Dr. Hesham Sadek, Assistant Professor of Internal Medicine at UT Southwestern and senior author of the study.

Due to the oxygen-rich atmosphere experienced immediately after birth, heart cells build up mitochondria -- the powerhouse of the cell -- which results in increased oxidization. The mass production of oxygen radicals by mitochondria damages DNA and, ultimately, causes cell cycle arrest.

"We have uncovered a previously unrecognized protective mechanism that mediates cardiomyocyte cell cycle arrest and that arises as a consequence of oxygen-dependent aerobic metabolism," said Dr. Sadek.

Physiologically speaking, Dr. Sadek said, mammals likely had to make the choice early on between being energy efficient or retaining the heart's ability to regenerate. "The choice was clear," said Dr. Sadek. "More than any organ in the body, the heart needs to be energy efficient in order to pump blood throughout life."

Heart muscle contains the highest amount of mitochondria in the body and consumes 30 percent of the body's total oxygen in a resting state alone. Unfortunately, the energy that comes from massive oxygen consumption comes with a price in the form of oxidation of DNA that makes the heart cells unable to divide and regenerate.

Dr. Sadek, along with co-first authors Dr. Bao "Robyn" Puente, postdoctoral trainee in Pediatrics, and Dr. Wataru Kimura, visiting senior researcher in Internal Medicine, found that if they subjected mice to a low-oxygen atmosphere, the cardiomyocytes divided longer than normal. The opposite was true when mice were born in a higher-oxygenated atmosphere. In that case, the cardiomyocytes stopped dividing earlier than normal.

This study comes on the heels of findings published in the Feb. 25, 2011, edition of Science, in which Dr. Sadek found that if a portion of a mouse heart was removed during the first week after birth, that portion grew back wholly and correctly. In contrast, an adult heart was irreversibly damaged by removal of even a small amount of tissue.

Because the adult mammal's heart is not able to regenerate following injury, this represents a major barrier in cardiovascular medicine. Having a promising new understanding of what arrests cardiomyocyte cell cycle could be an important component of cardiomyocyte proliferation-based therapeutic approaches.


Story Source:

The above story is based on materials provided by UT Southwestern Medical Center. Note: Materials may be edited for content and length.


Journal Reference:

  1. BaoN. Puente, Wataru Kimura, ShaliniA. Muralidhar, Jesung Moon, JamesF. Amatruda, KateL. Phelps, David Grinsfelder, BeverlyA. Rothermel, Rui Chen, JosephA. Garcia, CelioX. Santos, SuWannee Thet, Eiichiro Mori, MichaelT. Kinter, PaulM. Rindler, Serena Zacchigna, Shibani Mukherjee, DavidJ. Chen, AhmedI. Mahmoud, Mauro Giacca, PeterS. Rabinovitch, Asaithamby Aroumougame, AjayM. Shah, LukeI. Szweda, HeshamA. Sadek. The Oxygen-Rich Postnatal Environment Induces Cardiomyocyte Cell-Cycle Arrest through DNA Damage Response. Cell, 2014; 157 (3): 565 DOI: 10.1016/j.cell.2014.03.032

Cite This Page:

UT Southwestern Medical Center. "Oxygen diminishes heart's ability to regenerate, researchers discover." ScienceDaily. ScienceDaily, 24 April 2014. <www.sciencedaily.com/releases/2014/04/140424124955.htm>.
UT Southwestern Medical Center. (2014, April 24). Oxygen diminishes heart's ability to regenerate, researchers discover. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2014/04/140424124955.htm
UT Southwestern Medical Center. "Oxygen diminishes heart's ability to regenerate, researchers discover." ScienceDaily. www.sciencedaily.com/releases/2014/04/140424124955.htm (accessed October 25, 2014).

Share This



More Health & Medicine News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

IKEA Desk Converts From Standing to Sitting With One Button

IKEA Desk Converts From Standing to Sitting With One Button

Buzz60 (Oct. 24, 2014) IKEA is out with a new convertible desk that can convert from a sitting desk to a standing one with just the push of a button. Jen Markham explains. Video provided by Buzz60
Powered by NewsLook.com
Ebola Protective Suits Being Made in China

Ebola Protective Suits Being Made in China

AFP (Oct. 24, 2014) A factory in China is busy making Ebola protective suits for healthcare workers and others fighting the spread of the virus. Duration: 00:38 Video provided by AFP
Powered by NewsLook.com
WHO: Millions of Ebola Vaccine Doses by 2015

WHO: Millions of Ebola Vaccine Doses by 2015

AP (Oct. 24, 2014) The World Health Organization said on Friday that millions of doses of two experimental Ebola vaccines could be ready for use in 2015 and five more experimental vaccines would start being tested in March. (Oct. 24) Video provided by AP
Powered by NewsLook.com
Doctor in NYC Quarantined With Ebola

Doctor in NYC Quarantined With Ebola

AP (Oct. 24, 2014) An emergency room doctor who recently returned to the city after treating Ebola patients in West Africa has tested positive for the virus. He's quarantined in a hospital. (Oct. 24) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins