Researchers zero in on 'culprit' causing heart failure

New York, March 20 , 2015: Researchers have identified what they describe as "the long-sought culprit" that contributes to The research, published in the journal Nature, revealed that an enzyme called PDE-9 interferes with the body's natural "braking" system needed to neutralise stress on the heart. "Like a play with multiple characters, heart muscle function is the result of a complex but perfectly synchronised interaction of several proteins, enzymes and hormones," said lead investigator Dong Lee, cardiology research associate at the Johns Hopkins University School of Medicine in the US. Naturally found in the gut, kidneys and brain, PDE-9 is already a prime suspect in neurodegenerative conditions such as Alzheimer's, the researchers said. But the new study shows that the enzyme's footprints are also present in heart cells and markedly elevated in patients with heart failure - evidence that PDE-9 is a multi-tasking "offender" and a key instigator of heart muscle demise, they added. Working with lab animals and human heart cells, the scientists found that the enzyme PDE-9 wreaks mischief by gobbling up a signalling molecule, cGMP, which normally stimulates the production of a heart-protective protein called PKG. The protein PKG is known to shield the heart muscle from the ravages of disease-causing stress, such as long-standing high blood pressure.