Featured Research

from universities, journals, and other organizations

Heart muscle cell grafts suppress arrhythmias after heart attacks in animal study

Date:
August 5, 2012
Source:
University of Washington
Summary:
Researchers have made a major advance in efforts to regenerate damaged hearts. Grafts of human heart muscle cells reduced the incidence of irregular heart rhythms after heart attacks in animal studies. Grown from embryonic stem cells, the grafted cells couple electrically and contract in sync with the heart's own muscle. The results offer evidence that human heart muscle cell grafts meet physiological criteria for true heart regeneration.

Transplanted human heart cell grafts were electrically coupled with the recipient's own heart muscle.
Credit: Image from video by Michael Laflamme and Charles Murry, University of Washington

Researchers have made a major advance in efforts to regenerate damaged hearts. Grafts of human cardiac muscle cells, grown from embryonic stem cells, coupled electrically and contracted synchronously with host muscle following transplantation in guinea pig hearts.

The grafts also reduced the incidence of arrhythmias (irregular heart rhythms) in a guinea pig model of myocardial infarction (commonly known as a heart attack).

This finding from University of Washington-led research is reported in the Aug. 5 issue of Nature.

The paper's senior author, Dr. Michael Laflamme, said, "These results provide strong evidence that human cardiac muscle cell grafts meet physiological criteria for true heart regeneration. This supports the continued development of human embryonic stem cell-based heart therapies for both mechanical and electrical repair of the heart."

During a myocardial infarction the flow of oxygen-rich blood to the heart muscle is interrupted by formation of a clot, causing death of the down-stream heart muscle and its eventual replacement by scar tissue. This can cause mechanical problems with filling and emptying the heart, and it can also interfere with the electrical signals that pace the heartbeat.

In this study, the guinea pigs' hearts had an injury to the left ventricle, the thick walled lower chamber in the heart that pumps oxygenated blood to the body. The injury left a scar and thinned the ventricle, which showed both reduced pump function and greater susceptibility to arrhythmias.

Injured hearts that received the human cardiac muscle cell grafts showed partial re-muscularization of the scarred left ventricle.

Consistent with previous studies, tests showed that the injured hearts with the human cardiac cell grafts had improved mechanical function.

More surprisingly, these hearts showed fewer arrhythmias than did injured hearts without such grafts.

"We showed a couple years ago that transplanting human embryonic stem cell-derived heart muscle cells improves the pumping activity of injured hearts," said Dr. Michael Laflamme, UW associate professor of pathology and a member of the UW Center for Cardiovascular Biology and the Institute for Stem Cell & Regenerative Medicine.

"In this recent paper," he explained, "we show that the transplantation of these cells also reduces the incidence of arrhythmias [heart rhythm disturbances]."

Laflamme and Dr. Charles E. Murry, UW professor of pathology, bioengineering and medicine, Division of Cardiology, were the senior authors of the paper. The lead authors were Drs. Yuji Shiba and Sarah Fernandes in the UW Department of Pathology. Shiba is also from the Department of Cardiovascular Medicine at Shinshu University in Japan.

Because arrhythmias are a major cause of death in patients after a heart attack, Laflamme pointed out, this effect might be clinically useful if proven successful in large animal models as well.

Scientists had been worried that transplanting heart muscle cells derived from embryonic stem cells would promote arrhythmias.

"Instead, they suppress arrhythmias, at least in the guinea pig model," Laflamme and his team were pleased to discover.

While Laflamme and Murry had previously shown that transplanting these types of cell grafts improved pump function in injured hearts, Laflamme noted that it had not been previously determined if the grafts actually coupled and fired synchronously with heart's original muscle.

There was the possibility, he suggested, that they exerted their beneficial effects indirectly, perhaps by releasing signaling molecules, rather than by forming new force-generating units.

"In our study, we discovered that the heart cell grafts do, in fact, couple to the guinea pig hearts," he said.

The research team found the heart cell grafts electrically coupled in all of the normal, uninjured hearts into which they were transplanted, and in the majority of the injured hearts.

The researchers were able to observe this coupling by transplanting human heart muscle cells that were genetically modified to flash every time they fired. By correlating this optical signal from the graft cells with the electrocardiogram -- electrical signals from the recipient heart -- the researchers were able to determine whether cell grafts were electrically coupled with the animal's heart.


Story Source:

The above story is based on materials provided by University of Washington. Note: Materials may be edited for content and length.


Cite This Page:

University of Washington. "Heart muscle cell grafts suppress arrhythmias after heart attacks in animal study." ScienceDaily. ScienceDaily, 5 August 2012. <www.sciencedaily.com/releases/2012/08/120805144845.htm>.
University of Washington. (2012, August 5). Heart muscle cell grafts suppress arrhythmias after heart attacks in animal study. ScienceDaily. Retrieved September 18, 2014 from www.sciencedaily.com/releases/2012/08/120805144845.htm
University of Washington. "Heart muscle cell grafts suppress arrhythmias after heart attacks in animal study." ScienceDaily. www.sciencedaily.com/releases/2012/08/120805144845.htm (accessed September 18, 2014).

Share This



More Health & Medicine News

Thursday, September 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Cost of Ebola

The Cost of Ebola

Reuters - Business Video Online (Sep. 18, 2014) As Sierra Leone prepares for a three-day "lockdown" in its latest bid to stem the spread of Ebola, Ciara Lee looks at the financial implications of fighting the largest ever outbreak of the disease. Video provided by Reuters
Powered by NewsLook.com
What HealthKit Bug Means For Your iOS Fitness Apps

What HealthKit Bug Means For Your iOS Fitness Apps

Newsy (Sep. 18, 2014) Apple has delayed the launch of the HealthKit app platform, citing a bug. Video provided by Newsy
Powered by NewsLook.com
Residents Vaccinated as Haiti Fights Cholera Epidemic

Residents Vaccinated as Haiti Fights Cholera Epidemic

AFP (Sep. 18, 2014) Haitians receive the second dose of the vaccine against cholera as part of the UN's vaccination campaign. Duration: 00:34 Video provided by AFP
Powered by NewsLook.com
Artificial Sweetener Could Promote Diabetes

Artificial Sweetener Could Promote Diabetes

Newsy (Sep. 17, 2014) Doctors once thought artificial sweeteners lacked the health risks of sugar, but a new study says they can impact blood sugar levels the same way. Video provided by Newsy
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:
from the past week

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