Scientists use gene to help heart cells correct erratic rhythms

Scientists have successfully used a gene to convert ordinary heart cells into super-specialized pacemaker cells to correct erratic and failing heartbeats.

"Although we and others have created primitive biological pacemakers before, this study is the first to show that a single gene can direct the conversion of heart muscle cells to genuine pacemaker cells," said Hee Cheol Cho from the Cedars-Sinai Heart Institute.

"The new cells generated electrical impulses spontaneously and were indistinguishable from native pacemaker cells," added Hee, study co-author, reported the journal Nature Biotechnology citing a Cedars-Sinai statement.

Pacemaker cells generate electrical activity that spreads to other heart cells in an orderly pattern to create rhythmic muscle contractions. If these cells go awry, the heart pumps erratically at best; patients healthy enough to undergo surgery often look to an electronic pacemaker as the only option for survival.

Of the heart's 10 billion cells, fewer than 10,000 are pacemaker cells, often referred to as SAN cells.

But the Cedars-Sinai researchers, employing a virus engineered to carry the Tbx18 gene, that plays a key role in embryonic pacemaker cell development, directly reprogrammed heart muscle cells (cardiomyocytes) to specialized pacemaker cells.

Once reprogrammed by the Tbx18 gene, the newly created pacemaker cells - "induced SAN cells" or iSAN cells - had all key features of native pacemakers and maintained their SAN-like characteristics even after the effects of the Tbx18 gene had faded.

"This is the culmination of 10 years of work in our laboratory to build a biological pacemaker as an alternative to electronic pacing devices," said Eduardo Marban, director of the Cedars-Sinai Heart Institute and professor, a pioneer in cardiac stem cell research.

A clinical trial of Marban's stem cell therapy for heart attack patients recently found the experimental treatment helped damaged hearts regrow healthy muscle.