Heart failure (HF) is characterized by poor survival, a loss of catecholamine reserve and cellular structural remodeling in the form of disorganization and loss of the transverse tubule network. Indeed, survival rates for HF are worse than many common cancers and have not improved over time.
Tadalafil is a clinically relevant drug that blocks phosphodiesterase 5 with high specificity and is used to treat erectile dysfunction.
In a new study by the University of Manchester, scientists used this drug to slow or even reverse the progression of heart failure in sheep. And what’s fascinating, they found that the drug is biologically effective as a treatment for heart failure in sheep.
Lead author Professor Andrew Trafford said, “This discovery is an important advance in a devastating condition that causes misery for thousands of people across the UK and beyond. We do have limited evidence from human trials and epidemiological studies that show Tadalafil can be effective in treating heart failure.”
“This study provides further confirmation, adds mechanistic details, and demonstrates that Tadalafil could now be a possible therapy for heart failure. It’s entirely possible that some patients taking it for erectile dysfunction have also unwittingly enjoyed a protective effect on their heart.”
Sheep were used by the team as the physiology of their hearts is similar to human hearts.
When the animals had heart failure – induced by pacemakers – which was sufficiently advanced to need treatment, the team administered the drug. Within a short period, the progressive worsening of the heart failure was stopped and, importantly, the drug reversed the effects of heart failure. And the biological cause of breathlessness in heart failure- the inability of the heart to respond to adrenaline was almost completely reversed.
The research team found that in heart failure, the drug altered the signaling cascade – a series of chemical reactions in the body – to restore the heart’s ability to respond to adrenaline. And that increases the ability of the heart to force blood around the body when working harder.
Professor Trafford added: “This is a widely used and very safe drug with minimal side effects. However, we would not advise the public to treat themselves with the drug and should always be speaking to their doctor if they have any concerns or questions.”
“Tadalafil is only suitable as a treatment for systolic heart failure – when the heart is not able to pump properly – and there may be interactions with other drugs patients are taking.”
Professor Metin Avkiran, Associate Medical Director at the British Heart Foundation, said:
“Viagra-type drugs were initially developed as potential treatments for heart disease before they were found to have unexpected benefits in the treatment of erectile dysfunction. We seem to have gone full circle, with findings from recent studies suggesting that they may be effective in the treatment of some forms of heart disease – in this case, heart failure.
“We need safe and effective new treatments for heart failure, which is a cruel and debilitating condition that affects almost a million people in the UK. The evidence from this study – that a Viagra-like drug could reverse heart failure – should encourage further research in humans to determine if such drugs may help to save and improve lives.”