A Viagra-like drug widely used for the treatment of erectile dysfunction may provide an effective treatment for life-threatening heart failure.

UK scientists hailed the “breakthrough” findings after demonstrating the effects of the drug tadalafil, sold as Cialis, in sheep.

But they said it was “entirely possible” that some men being treated for impotence are already benefiting from the protection it affords.

Animals made to develop the disease did not progress into heart failure when given the drug, while those with the condition improved.

“This discovery is an important advance in a devastating condition which causes misery for thousands of people across the UK and beyond,” said Professor Andrew Trafford, from the University of Manchester, the lead researcher on the study.

Under the skin – best of the British Heart Foundation 2018 image prize Show all 10 1 /10 Under the skin – best of the British Heart Foundation 2018 image prize Under the skin – best of the British Heart Foundation 2018 image prize Subarachnoid vessels The runner-up image came from Matt MacGregor Sharp, a PhD student at the University of Southampton. The super-high resolution image shows a normal artery at the surface of a rat’s brain and was taken with a powerful scanning electron microscope. These ‘subarachnoid vessels’ supply blood to the brain and also act like a drain to remove toxic waste products. Matt Macgregor’s team are trying to show that failure to remove waste by these vessels is one of the underlying causes of vascular dementia. The researchers took the image using a technique called ‘freeze fracture’, where tissue or cell samples are frozen and then split apart to reveal the hidden layers within the sample so they can be studied in extreme detail. Sitting above the brown brain tissue, the artery appears blue, and its surrounding layer, the pia mater, is shown in purple. Matt MacGregor Sharp, University of Southampton, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Explosive beginnings Winner: Endothelial cells line all blood vessels in the body, forming a barrier between the circulating blood and the vessel wall. They also help to protect blood vessels from damage and release important chemical messengers which help to control blood pressure. The winning researcher, Courtney Williams, is a Masters student and PhD candidate at Leeds University. Her lab are developing new ways to map the growth of new blood vessels within their surrounding landscape in 3D. Understanding the complex secrets of blood vessel formation could be harnessed to boost the regrowth of damaged blood vessels after a heart attack, and halt blood vessel growth when it’s counterproductive. Courtney Williams, Leeds University, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize A snapshot of platelet production - Reflections of Research Supporters’ Favourite This image from Abdullah Obaid Khan, a PhD student at the University of Birmingham, won the supporters’ favourite. What look like precious jewels are actually platelets forming within the bone marrow. Platelets are the smallest of our circulating blood cells with a hugely important role in preventing bleeding. However, they also play a role in the formation of clots, which can lead to heart attacks and strokes. Abdullah Obaid Khan and his team are studying rare bleeding disorders. Abdullah Obaid Khan, University of Birmingham, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Cardiac collagen web - Shortlist This colourful image shows the web-like, network of the smallest blood vessels in the heart – the microvessels. Magenta marks the outer collagen layer of the vessels; while orange marks their inner lining and blue the cell nuclei. Dr Neil Dufton, Imperial College London Dr Neil Dufton, Imperial College London, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Heart to Heart - Shortlist This piece shows four ventricles (from a mouse) arranged into the shape of the hearts four normal chambers. The researchers have used fluorescent markers to recognise certain proteins and created the image using of hundreds of images assembled together. Dr Elisa Avolio and Dr Zexu Dang, University of Bristol Dr Elisa Avolio and Dr Zexu Dang, University of Bristol, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Loving artery - Shortlist This image shows a cross section of an artery and the different layers which make up the artery wall. Affiliate Professor Silvia Lacchini, University of Glasgow Silvia Lacchini, University of Glasgow, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Oxidative inkblot - Shortlist This colour explosion shows one of the culprits in cardiovascular disease – an enzyme called NADPH oxidase. The enzyme is considered ‘Janus faced’ because it is important in health, as well as disease. This picture shows the active enzyme in patients who have high blood pressure. Dr Livia de Lucca Camargo, University of Glasgow Dr Livia de Lucca Camargo, University of Glasgow, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Neon skeleton - Shortlist This image shows the developing blood vessel system of a two day old zebrafish embryo. The researchers used gene enhancers (the on-off switches of genes) to switch on fluorescent markers in different types of endothelial cells – the important cells which line all blood vessels. All blood vessels switch on the red marker, while the veins also switch on the green marker, resulting in yellow veins and red arteries. Dr Svanhild Nornes, University of Oxford Dr Svanhild Nornes, University of Oxford, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Calcium reef - Shortlist This image shows calcium in blood vessel cells from people who have high blood pressure and resembles Australia’s Great Barrier Reef. Dr Rheure Alves-Lopes, University of Glasgow Dr Rheure Alves-Lopes, University of Glasgow, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Budding blood vessels - Shortlist This image shows the growing blood vessels in the mouse retina. In red you can see all the blood vessels and in yellow/green you can see the blood vessels that are actively growing (a process called sprouting). PhD candidate Kira Chouliaras, University of Oxford Kira Chouliaras, University of Oxford, British Heart Foundation - Reflections of Research

He added that limited evidence from human trials and epidemiological studies demonstrates tadalafil can be effective in treating heart failure, but this study explains why it is so effective, and shows it to be a possible therapy.

“It’s entirely possible that some patients taking it for erectile dysfunction have also unwittingly enjoyed a protective effect on their heart,” Professor Trafford said.

Heart failure occurs when the heart is too weak to pump sufficient blood around the body. It can follow a heart attack, or be caused by a genetic abnormality.

People affected by heart failure are quickly exhausted and suffer breathlessness and swelling caused by fluid backing up in the lungs.

As the condition worsens it can become life-threatening. Five-year survival rates for heart failure are lower than for most common cancers.

For the study, published in the journal Scientific Reports, sheep were fitted with pacemakers that induced heart failure advanced enough to need treatment.

The animals were chosen because they have hearts similar to those of humans.

Cialis almost completely reversed the biological cause of breathlessness in sheep with heart failure – the inability of the heart to respond to adrenaline.

The heart’s ability to force blood around the body when working harder was increased.

However, Professor Trafford warned patients not to self-treat, despite it being widely used, because of potential interactions with other drugs or conditions.

Professor Metin Avkiran, from the British Heart Foundation, which funded the study, said Viagra-like drugs were initially developed as heart medications.

“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,” he said.

“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.”

Tadalafil acts like Viagra but is favoured by many men because of its longer-lasting effects.