Scientists simulated human heart failure in pigs by obstructing blood flow in the heart's main artery. They then injected a gene known as SUMO-1 and found that the animals' enlarged hearts returned to normal size and heart function improved.
'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', said Dr Roger Hajjar, director of the Cardiovascular Research Centre at Mount Sinai Hospital, USA, who led the study.
The genes were delivered into the pigs using a deactivated cold-type virus known as an adeno-associated virus, which was injected directly into the heart.
The researchers also tested the effects of another gene, SERCA2, as well as using both genes in concert. The hearts of pigs that received both genes were found to beat harder than if only one gene was used.
SUMO-1 is involved in calcium signalling, a vital component in ensuring heart muscle cells beat normally. It activates and stabilises the SERCA2 gene, which the researchers describe as being the heart's calcium pump.
'These new study findings support the critical role SUMO-1 plays for SERCA2 function, and underline the therapeutic potential of SUMO-1 gene replacement therapy for heart failure patients', said Dr Hajjar.
Gene therapy trials using SERCA2 have begun on patients in the UK (as reported in BioNews 721).
Heart failure affects around 750,000 people in the UK, and because there is no cure, most patients must rely on a combination of medicines, devices such as pacemakers, or surgery.
The team hopes to start a clinical trial of this kind of gene therapy within the next few years. 'We are very eager to test this gene therapy in our patients suffering from severe heart failure', said Dr Hajjar.
The results were published in Science Translational Medicine.