Viagra could potentially help prevent Alzheimer’s disease, according to a new study published in the Nature Aging journal.
Sildenafil, better known as Viagra, was originally developed to treat hypertension and angina pectoralis (high blood pressure and chest pain). During early clinical trials, however, it soon became clear that sildenafil was an effective treatment for erectile dysfunction. Since 1998, it has been widely prescribed for this indication.
In their Nature Aging study, a team of researchers led by Dr. Feixiong Cheng at the Cleveland Clinic used a computer-based approach to identify genes associated with both amyloid and tau, two proteins that are linked to the development of Alzheimer’s disease (AD). They then crossreferenced this molecular map with the targets of over 1,600 drugs currently approved by the US Food and Drug Administration (FDA), identifying 66 drugs that targeted the AD-associated genes. Of these, sildenafil – or Viagra - was one of the top candidate drugs, thanks to its mode of action which targets an enzyme called phosphodiesterase 5 (PDE5).
Next, the researchers analysed the medical records of 7.23 million men who had taken sildenafil, looking at whether they were diagnosed with AD over a 6-year follow-up period. Comparing this group with peers who had not taken sildenafil, they found that men who had taken sildenafil were 69% less likely to develop AD, even when factors such as age, sex, race and cardiovascular comorbidities were taken into account.
To understand how the drug might be acting on the brain, the researchers performed laboratory experiments using brain cells derived from stem cells donated by people with AD. These studies indicated that sildenafil could improve brain cell function and reduce the expression of tau. Further research, including a randomised, controlled trial involving women as well as men, are required to check whether there is a direct, causal link between sildenafil use and AD prevention.
https://www.nature.com/articles/s43587-021-00138-z
