US researchers said Wednesday they have successfully tested a powerful gene therapy, delivered directly into the heart, to reverse heart failure in pigs.

The findings, published in the US journal Science Translational Medicine, is the final study phase before human clinical trials can begin testing SUMO-1 gene therapy, researchers at the Cardiovascular Research Center at Icahn School of Medicine at Mount Sinai said.

According to the researchers, SUMO-1 is a gene that is "missing in action" in heart failure patients.

"SUMO-1 gene therapy may be one of the first treatments that can actually shrink enlarged hearts and significantly improve a damaged heart's life-sustaining function," senior investigator Roger Hajjar, director of the Cardiovascular Research Center, said in a statement. "We are very eager to test this gene therapy in our patients suffering from severe heart failure."

Heart failure, a leading cause of hospitalization in the elderly, occurs when a person's heart is too weak to properly pump and circulate blood throughout their body.

Recent clinical trials have shown that replacing SERCA2, a gene that regulates the heart's calcium pump, can reduce heart failure, but Hajjar and his research group found that SUMO-1 can also effectively soothe ailing hearts.

By binding to and restoring the function of the SERCA2 pump, SUMO-1 is like a plumber on speed dial that quickly repairs the heart, they said.

The researchers simulated human heart failure in pigs by obstructing blood flow in the heart's main artery and tested delivery of SUMO-1 gene therapy alone, SERCA2 gene therapy alone, and a combination of SUMO-1 and SERCA2.

They found that gene therapy delivery of high dose SUMO-1 alone, as well as SUMO-1 and SERCA2 together, result in stronger heart contractions, better blood flow, and reduced heart volumes, compared to just SERCA2 gene therapy alone.

"These new study findings support the critical role SUMO-1 plays for SERCA2 function, and underlie the therapeutic potential of SUMO-1 gene replacement therapy for heart failure patients," Hajjar said.

The researchers said that they hope to start a Phase one clinical trial within the next few years and that beyond heart failure SUMO-1 may be a promising target for pulmonary hypertension and vascular diseases.