Scientists Devise Strategy to Fix Broken Heart

Posted on Aug 30, 2010 in Cardiovascular Health

Scientists have devised a new strategy to fix the broken heart – a tiny scaffold that they claim will repair damaged cardiac muscle cells and help prevent congestive heart failure.
 
The University of Washington researchers, who developed the scaffold, said the damage to heart muscle following a heart attack is irreversible and it leads to congestive heart failure – the most common cause of death in developed countries.
 
But the scaffold, which supports the growth of cardiac cells and blood vessels in laboratory animals, can be a new strategy to prevent people dying from congestive heart failure, they said in a release. 
 
“Today, if you have a heart attack there’s nothing that doctors can do to repair the damage,” said lead author Buddy Ratner, a professor of bioengineering at the university.
 
“You are, in essence, sentenced to a downhill slide, developing congestive heart failure that greatly shortens your lifespan.”
 
“Your body can’t make new heart cells, but what if we can deliver vital new cells in that damaged portion of the heart?”
 
The tiny tubular porous scaffold, made from a jelly-like hydrogel material, can be injected into a damaged heart, where it will foster cell growth and eventually dissolve away, the researchers said.
 
It not only supports cardiac muscle growth, but also accelerates the body’s ability to supply oxygen and nutrients to the transplanted tissue.
 
The idea is, the scientists said, doctors can seed the scaffold with stem cells from either the patient or a donor, and then implant it when the patient is treated for a heart attack, before scar tissue has formed.
 
The scaffold, a flexible polymer with interconnected pores all of the same size, also includes channels to accommodate cardiac cells’ preference for fusing together in long chains, the researchers wrote in the journal Proceedings of the National Academy of Sciences.
 
The scientists first verified the design using chicken embryonic heart cells, and confirmed that the scaffold could support heart tissue growth at concentrations similar to those in living heart tissue.
 
They then seeded the scaffold with cardiac muscle cells derived from human embryonic stem cells. These cells survived and collected in the channels.
 
Over five days, the cardiac muscle cells multiplied faster in the scaffold environment than other cell types, and could survive up to 300 micrometres (about the diameter of four human hairs) from the scaffold edge — an important point if the scaffold is to integrate with the body.
 
According to co-author Chuck Murry, professor of pathology and bioengineering, heart tissues need a rich blood supply, and that’s been one of the limiting factors to heart repair and vascular tissue engineering.
 
“The first thing that transplanted heart cells have to do is survive. And when you transition them from a culture dish to the body, initially they don’t have a blood supply. So we have to promote the host blood supply as fast as possible,” Murry said.
 
“We’re very optimistic that this scaffold will help keep the muscle cells alive after implantation and will help transition them to working heart muscles.”