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Using Viagra could help prevent Alzheimer’s disease developing, a new study shows

This Monday, Dec. 4, 2017 photo shows Pfizer's Viagra, left, and the company's generic version, sildenafil citrate, at Pfizer Inc., headquarters in New York.
This Monday, Dec. 4, 2017 photo shows Pfizer's Viagra, left, and the company's generic version, sildenafil citrate, at Pfizer Inc., headquarters in New York.   -   Copyright  Richard Drew/AP
By Julie Gaubert

Could a drug used to combat male impotence help maintain your mental faculties too?

In a study published in the journal Nature Aging, researchers from the University of Cleveland (USA) suggest that sildenafil, the medicine branded as Viagra, could be prescribed to prevent Alzheimer's disease.

After analysing the medical data of more than 7 million patients, they found that men who regularly took Viagra had a 69 per cent lower risk of suffering from Alzheimer's disease.

Before it became one of the best-known drugs for erectile dysfunction, Viagra was developed to improve blood circulation by acting on the vessels.

It is also prescribed to patients with pulmonary hypertension, high blood pressure in the veins supplying the lungs.

Researchers investigated whether it could also help people at risk of vascular dementia, a disease that occurs when reduced blood flow damages the brain.

Why viagra?

Using a large gene-mapping network, researchers integrated genetic and other biologic data to determine which of over 1,600 drugs approved by the Food and Drug Administration (FDA) for sale in the United States could be an effective treatment for Alzheimer’s disease.

Sildenafil is one of a cohort of medication - along with diltiazem, glimepiride, losartan and metformin - being tested for targeting both amyloid and tau proteins, the accumulation of which in the brain leads to the development of Alzheimer's disease.

"Sildenafil, which has been shown to significantly improve cognition and memory in preclinical models, presented as the best drug candidate,” Dr Feixiong Cheng, lead author of the study and member of the Genomic Medicine Institute at the Cleveland Clinic, said.

“It may have neuroprotective effects and reduce levels of toxic proteins".

The research team used a large database of 7.23 million people in the US to examine the relationship between sildenafil and Alzheimer’s disease outcomes by comparing sildenafil users to non-users.

They found that sildenafil users were 69 per cent less likely to develop Alzheimer’s disease than non-sildenafil users after 6 years of follow-up.

Specifically, sildenafil had a 55 per cent reduced risk of the disease compared to losartan, 63 per cent compared to metformin, 65 per cent compared to diltiazem and 64 per cent compared to glimepiride.

“Notably, we found that sildenafil use reduced the likelihood of Alzheimer’s in individuals with coronary artery disease, hypertension and type 2 diabetes, all of which are comorbidities significantly associated with risk of the disease, as well as in those without,” added Cheng.

Too soon to claim it a treatment

To further explore sildenafil’s effect on Alzheimer’s disease, the researchers developed an “Alzheimer’s patient-derived brain cell model” using stem cells.

In the model, they found that sildenafil increased brain cell growth and decreased hyperphosphorylation of tau proteins - a build-up of which is a hallmark of Alzheimer’s. Researchers believe this offers biological insights into how sildenafil may influence disease-related brain changes.

“Because our findings only establish an association between sildenafil use and reduced incidence of Alzheimer’s disease, we are now planning a mechanistic trial and a phase II randomised clinical trial to test causality and confirm sildenafil’s clinical benefits for Alzheimer’s patients,” said Cheng.

“We also foresee our approach being applied to other neurodegenerative diseases, including Parkinson’s disease and amyotrophic lateral sclerosis, to accelerate the drug discovery process”.

Canva
Sildenafil, which has been shown to significantly improve cognition and memory in preclinical models, presented as the best drug candidate,” Dr Feixiong Cheng said.Canva

Yet, the doctor warns that it is still too early to take viagra for the prevention of Alzheimer's disease.

Randomised clinical trials involving both sexes with a placebo control are still needed to determine the effectiveness of sildenafil, Cheng added.

Additional sources • University of Cleveland