Gene therapy helps pigs grow their own pacemakers

NEW YORK, July 16 (UPI) --Pacemakers are one of modern medicine's great inventions. The mechanical timekeeping device essentially salvages failing hearts, saving 3,000 lives every year. Despite their accomplishments, scientists have been looking for an alternative: A way to avoid the invasive surgery -- and the associated risks -- required by traditional pacemakers.

A new gene therapy technique suggests humans may be able to just grow their own. While the technique hasn't yet been tested on humans, it has offered promising results in experiments on mice and now, most recently, on pigs.

The technique is as follows: scientists inject a gene called TBX18 into heart muscle cells. The gene causes normal heart cells to transform into the type of special cells that dictate the speed of the pumping heart. The genes actually aren't injected directly into the heart, but are loaded onto deactivated cold viruses which infect the heart cells and deliver the new code.

"This development heralds a new era in gene therapy, where genes are used not only to correct deficiency disorders but to convert one cell to another to treat disease," said Dr. Eduardo Marban -- director of the Cedars-Sinai Heart Institute, in New York, and author of the new pig study, which was featured this week in the journal Science Translational Medicine.

A few days after being injected with the TBX-infected viruses, pigs with withering pacemakers had faster pulses. Their heart also showed the ability to speed up and slow down during exercise.

But Marban and his colleagues say more research is needed to determine potential side effects, like what would happen if the virus somehow enabled the transformation of regular-to-pacemaker cells in two different places.

Still, the new study is promising.

"Now that we and others are hot on the trail of developing therapeutics based on this principle of cell reprogramming," Marban added, "I anticipate that the flood gates will open and people will look for genes of interest to do whatever they want in particular organs or tissues of interest."

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Gene therapy helps pigs grow their own pacemakers