A new scaffold designed by scientists can help mend broken hearts. At least, the physical ones.
The scaffold supports the growth and integration of stem cell-derived cardiac muscle cells-a feat that offers hope for mending what the body can't do.
The scaffold, built by engineers and physicians at the University of Washington, supports the growth of cardiac cells in the lab and encourages blood vessel growth in living animals.
"Today, if you have a heart attack there's nothing that doctors can do to repair the damage. You are, in essence, sentenced to a downhill slide, developing congestive heart failure that greatly shortens your lifespan," said lead author Buddy Ratner, a UW professor of bioengineering.
"Your body can't make new heart cells, but what if we can deliver vital new cells in that damaged portion of the heart?" he added.
Ratner and his colleagues built a tiny tubular porous scaffold that supports and stabilizes the fragile cardiac cells and can be injected into a damaged heart, where it will foster cell growth and eventually dissolve away.
The new scaffold not only supports cardiac muscle growth, but potentially accelerates the body's ability to supply oxygen and nutrients to the transplanted tissue.
Eventually, the idea is that doctors would seed the scaffold with stem cells from either the patient or a donor, then implant it when the patient is treated for a heart attack, before scar tissue has formed.
Ratner's scaffold is a flexible polymer with interconnected pores all of the same size.
This one also includes channels to accommodate cardiac cells' preference for fusing together in long chains.
"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," said a co-author.
The scaffold is made from a jelly-like hydrogel material developed by first author, UW bioengineering doctoral student Lauran Madden.
A needle is used to implant the tiny (third of a millimeter wide by 4 millimeters long) scaffold rods into the heart muscle.
But the scaffold can support growth of larger clumps of heart tissue, said Madden.
The next steps will involve adjusting the scaffold degradation time so that the scaffold degrades at the same rate that cardiac cells proliferate and that blood vessels and support fibers grow in, and then implant a cell-laden scaffold into a damaged heart.
"What we have now is a really good system going in the dish, and we're working to transition it to in the body," said Madden.
The study has been published in the Proceedings of the National Academy of Sciences.