[extropy-chat] fwd: 'Heart-renewing' cells discovered

[Damien Broderick]

'Heart-renewing' cells discovered
Reuters
10feb05

SCIENTISTS have discovered cells in newborn hearts which divide and develop 
into mature heart muscle and could provide a new approach to treating 
cardiac patients.

The cells, known as isl1+, were found by a team of researchers at the 
University of California, San Diego (UCSD) in the hearts of newborn rats, 
mice and humans.

"This represents the fundamental discovery of a new human heart cell, one 
that is programmed to become cardiac muscle but is not yet triggered to do 
so," said Kenneth Chien, director of the UCSD Institute of Molecular 
Medicine who headed the research team.

The progenitor cells identified by Chien and his colleagues were found in 
areas of the heart where the bulk of congenital heart problems occur, which 
suggests they play an important role in remodelling and repairing the 
newborn heart.

"These cells represent an important finding because they identify clearly, 
using genetic tools, the cells that normally are responsible for forming 
the heart in the living embryo and show that a rare subset persists after 
birth, which is surprising," Chien told Reuters.

Although the cells, described in the latest issue of the science journal 
Nature, will not become a completely new heart, Chien said they can be 
grown on nearby heart cells and could be used to replace mechanical devices 
and valves to keep young damaged hearts pumping .

"Conceptually, these cells could provide a cell therapy-based approach to 
cardiac disease, which is new for cardiology," Chien said.

The scientists initially found the progenitor cells in an area of the heart 
called the atrium in newborn rats. They were able to genetically tag the 
cells in human embryonic tissue and in the hearts of mice. They showed the 
cells spontaneously formed cardiac muscle tissue.

Because the cells were found in a region of the atrium that is usually 
discarded during cardiac surgery, the researchers believe there may be some 
similar cells in the adult heart.

"The cardiac muscle cells formed were totally mature and had the complete 
array of function that one would expect in completely differentiated heart 
tissues," said Jason Lam, one of the first authors of the study, in a 
statement.

In a commentary on the research, Christine Mummery of the Institute of the 
Netherlands in Utrecht said the research suggests the heart has some 
regenerative capacity.

"The heart was thought to lack the capacity to regenerate after injury. But 
the identification of cells that can divide and mature into heart muscle 
suggests that the heart has repair mechanisms after all," she said.

Reuters