Biocompatible patch heals infants with birth defects (w/ video)

Biocompatible patches to repair congenital heart defects are under development at Rice University and Texas Children's Hospital. The patches are seeded with live heart cells and, after incubation, beat under their own power. Credit: Jeff Fitlow/Rice University

(Medical Xpress)—A painstaking effort to create a biocompatible patch to heal infant hearts is paying off at Rice University and Texas Children's Hospital.

The proof is in a in Jeffrey Jacot's lab, where a small slab of gelatinous material beats with the rhythm of a living heart.

Jacot, lead author Seokwon Pok, a at Rice, and their tissue-engineering colleagues have published the results ofyears of effort to produce a material called a bioscaffold that could be sutured into the hearts of infants suffering from birth defects. The scaffold, seeded with living , is designed to support the growth of healthy new tissue. Over time, it would degrade and leave a repaired heart.

The research was detailed in the Elsevier journal .

Patches used now to repair are made of or are taken from cows or from the patient's own body. About one in 125 babies born in the United States suffers such a defect; three to six of every 10,000 have what's known as a defect called Tetralogy of Fallot, a cause of "blue baby syndrome" that requires the surgical placement of a patch across the heart's right ventricular outflow tract.

Current strategies work well until the patches, which do not grow with the patient, need to be replaced, said Jacot, an assistant professor of bioengineering at Rice University, director of the Pediatric Cardiac Bioengineering Laboratory at the Service at Texas Children's Hospital and an adjunct professor at Baylor College of Medicine.

Biocompatible patches created in a lab at Texas Children's Hospital can be seeded with an infant's own cells for implantation to repair heart defects. The patches were developed by Jeffrey Jacot, a bioengineering professor at Rice University with a joint appointment at Texas Children's. Credit: Jeff Fitlow/Rice University

"None of those patches are alive," Jacot said, including the biologically derived patches that are "more like a plastic" and are not incorporated into the heart tissue.

"They're in a muscular area in the heart that's important for contraction and, more so, for electrical conduction," he said. " have to go around this area of . And having dead tissue means the heart produces less force, so it's not surprising that children with these types of repairs are more at risk for developing heart failure, arrhythmias and fibrillation.

"What we're making can replace current patches in an operation that surgeons are already familiar with and that has a very high short- and medium-term success rate, but with long-term complications," he said.

This video is not supported by your browser at this time.

A better scaffold would have to perform many functions perfectly. It must be strong enough to withstand the pressures delivered by a beating heart yet flexible enough to expand and contract; porous enough to allow new heart cells to migrate, make connections and excrete their own natural scaffold to replace the patch; and tough enough to handle sutures but still be able to biodegrade over just the right amount of time for natural tissue to take over.

The sandwich the researchers created seems to fill the bill on all counts. In the middle is a self-assembled polycaprolactone (PCL) polymer that hardens into a tough but stretchable ribbon. Mixing two types of PCL with different molecular weights allows tiny pores to form along the rough surface. The "bread" is a hydrogel made from a 50/50 mixture of gelatin and chitosan, a widely used material made from the shells of crustaceans like shrimp.

Heart cells cultured on the hydrogel surface were able to thrive and formed networks and ultimately beat. Though cells could not attach to the surface or pass through the pores of the PCL, the pores do allow nutrients to migrate from one side to the other, Jacot said. They also allow the hydrogel to hold on to the PCL core.

The lab tested the biodegradable qualities of the PCL and found that over 50 days, about 15 percent dispersed, leaving a ragged sheet. "It degrades in water," Jacot said. "If it's in the body, it will degrade, but it will be very slow, over the course of months.

"It should be stable for long enough that it allows muscular tissue to build up and take over the mechanical process. We want apatch we can suture in that can instantly handle ventricular pressure. But if we look at it later, we want it to look like normal tissue," he said.

Years of testing await the researchers before human trials can begin, but Jacot and his team are already looking ahead to the possibilities their success could offer. They hope to find a way to mix stem cell-derived heart cells from a patient into the hydrogel at the beginning of the process; stem cells may be drawn from several possible sources, including amniotic fluid routinely drawn from the newborn's mother, the subject of ongoing study by Jacot's lab. The cells would make a patch genetically identical to the child that could be implanted shortly after birth.

"If we can make a patch that works immediately," Jacot said, "one that contracts and conducts and has living cells and grows with the patient, what other surgeries can we do that nobody can do now?"

More information: www.sciencedirect.com/science/… ii/S1742706112005247

Related Stories

Scientists make strides toward fixing infant hearts

Feb 06, 2012

Researchers at Rice University and Texas Children's Hospital have turned stem cells from amniotic fluid into cells that form blood vessels. Their success offers hope that such stem cells may be used to grow ...

A strategy to fix a broken heart (w/ Video)

Aug 09, 2010

These days people usually don't die from a heart attack. But the damage to heart muscle is irreversible, and most patients eventually succumb to congestive heart failure, the most common cause of death in ...

Umbilical cord blood may help build new heart valves

Nov 10, 2008

Children with heart defects may someday receive perfectly-matched new heart valves built using stem cells from their umbilical cord blood, according to research presented at the American Heart Association's Scientific Sessions ...

Scientists overcome obstacles to stem cell heart repair

Dec 13, 2007

Scientists funded by the Biotechnology and Biological Sciences Research Council (BBSRC) at Imperial College London have overcome two significant obstacles on the road to harnessing stem cells to build patches ...

Recommended for you

Strategy proposed for preventing diseases of aging

9 hours ago

Medicine focuses almost entirely on fighting chronic diseases in a piecemeal fashion as symptoms develop. Instead, more efforts should be directed to promoting interventions that have the potential to prevent ...

User comments

Adjust slider to filter visible comments by rank

Display comments: newest first

TheGhostofOtto1923
4.4 / 5 (13) Dec 12, 2012
See this is progress. Soon it will be possible to fix and prevent damage in the womb, at which time it will become an ethical imperative to do so.

Perhaps they will soon devise a whole head patch for infants born with grotesque mental deformities such as are exhibited by some of the lying trolls (pussytard) on this site? This can only serve to improve life for all of us.
h20dr
not rated yet Dec 12, 2012
Biomechanics at work, cool.
obama_socks
1 / 5 (4) Dec 12, 2012
See this is progress. Soon it will be possible to fix and prevent damage in the womb, at which time it will become an ethical imperative to do so.

Perhaps they will soon devise a whole head patch for infants born with grotesque mental deformities such as are exhibited by some of the lying trolls (pussytard) on this site? This can only serve to improve life for all of us.
-TheghostofBlotto1923

Your pussytard is no longer on physorg, you stupid freak. You ruined her enjoyment of commenting on medicalxpress threads. Remember all the intimidation and lying about Pussycateyes that you did, Blotto?
You and your sock puppets exude a "foul body odor" in every thread where you go in to post your foul stupidity and irrationality.
It is evident that YOUR mental damage was not prevented while you were growing in your mother's rectum.

Blotto will now call me a phony NASA engineer even though I'm not employed by NASA.

Muahahahahahahahhhaaah
TheGhostofOtto1923
4.4 / 5 (14) Dec 12, 2012
Blotto will now call me a phony NASA engineer even though I'm not employed by NASA.
Well you are a genuine liar thats for sure.
obama_socks
1 / 5 (4) Dec 12, 2012
Blotto will now call me a phony NASA engineer even though I'm not employed by NASA.
Well you are a genuine liar thats for sure.


Muahahahahahhahahaahaaahhaaa
Grallen
not rated yet Dec 14, 2012
It makes me wonder if the survivors will further produce more children that require this intervention...

I suppose we will figure how to manipulate their genes to prevent it not long after this question becomes relevant anyways.