Gene therapies to fix failing hearts gain steam after years in the doldrums

A new wave of gene therapies aims to regenerate heart muscle cells to treat heart failure. A first clinical trial focused on growing new heart-muscle cells is underway, while companies are developing multiple additional regenerative gene therapies for heart conditions. The mammalian heart repairs poorly and is difficult to manipulate for regeneration, and some scientists question whether current trial data demonstrate true regeneration through cell division. The field also carries controversy, including retracted papers and a closed laboratory. Heart failure occurs when the heart cannot pump enough blood, and existing drugs mainly relieve symptoms rather than address underlying causes such as stiffness or weak pumping. Researchers say continued work is necessary to eventually achieve effective regeneration.

"The mammalian heart is bad at repairing itself and "is notoriously unwieldy when it comes to efforts to try to get it to regenerate", says Sean Wu, a cardiologist at Stanford University in California. Some scientists are unconvinced that the data underpinning the existing clinical trial show true regeneration in the form of cell division. And efforts to regenerate the heart are still haunted by a controversy that led to the retraction of at least a dozen papers and the closure of a high-profile laboratory."

"Heart failure occurs when the organ can't pump enough blood for the body's needs. The condition is becoming increasingly common in some nations. In the United States, for example, the prevalence is expected to rise by 50% in the next 15 years. The few existing drugs treat symptoms without fixing the root of the problem: the heart is either too stiff to properly fill with blood or too weak to pump it."

"Developing a gene therapy in this field will be difficult, says Antonio Abbate, a cardiologist at the University of Virginia in Charlottesville. But "we have to do research because, eventually, we'll get it right". The first trial of a gene therapy for heart failure, launched in 2007, was not aimed at regenerating the heart. Instead, it tried to improve the ability of heart-muscle cells, or cardiomyocytes,"

"The first clinical trial aimed at growing new heart-muscle cells is now under way, and companies are developing at least four other regenerative gene therapies for heart conditions. "These are [the] first-in-human studies to take regeneration into the clinic," says Andrew Baker, a gene-therapy researcher at the University of Edinburgh, UK, who is unaffiliated with the efforts. "It's a very exciting time.""

Read at Nature