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 July 23, 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 July 23, 2014).

Share This




More Health & Medicine News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Courts Conflicted Over Healthcare Law

Courts Conflicted Over Healthcare Law

AP (July 22, 2014) Two federal appeals courts issued conflicting rulings Tuesday on the legality of the federally-run healthcare exchange that operates in 36 states. (July 22) Video provided by AP
Powered by NewsLook.com
Why Do People Believe We Only Use 10 Percent Of Our Brains?

Why Do People Believe We Only Use 10 Percent Of Our Brains?

Newsy (July 22, 2014) The new sci-fi thriller "Lucy" is making people question whether we really use all our brainpower. But, as scientists have insisted for years, we do. Video provided by Newsy
Powered by NewsLook.com
Scientists Find New Way To Make Human Platelets

Scientists Find New Way To Make Human Platelets

Newsy (July 22, 2014) Boston scientists have discovered a new way to create fully functioning human platelets using a bioreactor and human stem cells. Video provided by Newsy
Powered by NewsLook.com
Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

TheStreet (July 21, 2014) New research shows Gilead Science's drug Sovaldi helps in curing hepatitis C in those who suffer from HIV. In a medical study, the combination of Gilead's Hep C drug with anti-viral drug Ribavirin cured 76% of HIV-positive patients suffering from the most common hepatitis C strain. Hepatitis C and related complications have been a top cause of death in HIV-positive patients. Typical medication used to treat the disease, including interferon proteins, tended to react badly with HIV drugs. However, Sovaldi's %1,000-a-pill price tag could limit the number of patients able to access the treatment. TheStreet's Keris Lahiff reports from New York. Video provided by TheStreet
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