Does Viagra have an impact on health? If it does, will it benefit the user? So, researchers made use of genetic and other biological data available and they recently came up with an interesting conclusion: Viagra (sildenafil) may possibly influence Alzheimer’s disease.
What the group of researchers did was analyze insurance claims for prescriptions. They discovered how sildenafil scrips were associated with a 69 percent reduced risk of Alzheimer’s in claimants. Furtherlaboratory tests on nerve cells from people with Alzheimer’s were conducted and the findings supported the idea that sildenafil may actually treat the disease.
Of course, the conclusions have yet to be solidified. The researchers stressed how only clinical trials can provide definitive proof that sildenafil can be effective treatment for those who suffer from Alzheimer’s disease.
Doctors often prescribe sildenafil (or what is more popularly known as Viagra, its brand name) to treat erectile dysfunction and pulmonary arterial hypertension. The latter means high blood pressure in the lungs. Still, several studies have been made in mice, and there have also been a few pilot studies in humans. The findings have somewhat pointed to the fact that sildenafil could also be used for treatment of Alzheimer’s disease.
The Studies Made
A new study has been made and this has now provided biological and population-based proof to support the experts’ idea that the drug could actually help prevent and treat Alzheimer’s Disease. “Developing drugs for diseases, like Alzheimer’s, which attack the brain, is a costly process and can take many years,” Dr. Susan Kohlhaas, Ph.D., director of research at Alzheimer’s Research UK in the United Kingdom, said when she spoke to Medical News Today.
She further explained, “Being able to repurpose a drug already licensed for other health conditions could help speed up the drug discovery process and bring about life-changing dementia treatments sooner.”
The study was led by the Genomic Medicine Institute at the Cleveland Clinic in Cleveland, OH. The findings and details are elaborated in Nature Aging. When it comes to Alzheimer’s disease, which is the most common form of dementia, the death of brain cells lead to progressive memory loss and cognitive decrease. Because of the aging population, scientists believe and predict that by the year 2050, around 13.8 million people in the United States will have suffer from Alzheimer’s.
Visible Hallmarks of Alzheimer’s
The disease comes with several hallmarks. As the doctors observed the brain, they saw plaques of a protein called beta-amyloid and fibrous tangles of tau, another protein. Unfortunately, at this point in time, clinical trials of drugs and vaccines that target the two proteins have yet to be effective. The scientists have been disappointed with the results so far.
They believe that there is a complex interplay of both genes and environmental factors that leads to Alzheimer’s. To be able to tell which of the existing drugs could provide new treatments, the researchers made use of a computational model that assimilates data about the disease’s genetics and the involved networks of metabolic pathways. They also honed in on interactions between proteins in networks that play have a role in the creation of both beta-amyloid and tau.
Then, the researchers generated “network proximity measures” for more than the 1,600 approved drugs. They looked at how closely each of these interacted with these Alzheimer’s-related networks. With the observations made, the scientists were able to narrow down the field to just 66 drugs that could be a potential treatment. They also considered other factors, included are the promising results from experiments made in animal models. So far, they saw how sildenafil came out as the most potential cure.
The researchers also conducted further studies and analyzed the insurance claims for prescriptions from a total of 7.23 million people. Generally, they saw that claimants who were prescribed sildenafil had reduced risk of Alzheimer’s over the next 6 years of about 69 percent.
The association they saw had statistically significant results after they accounted for other factors that influence Alzheimer’s risk. Other factors include sex, ethnicity, and other medical conditions. Included are also type 2 diabetes, high blood pressure, coronary artery disease, and mild cognitive impairment.
Lastly, to further confirm how sildenafil has the ability to affect the underlying mechanism of Alzheimer’s, the researchers also tested the drug in the lab. They made use of nerve cells from those who suffer from the disease. They saw how the drug was able to promote the growth of new nerve projections and decreased tau accumulation found in the cells. This is crucial because researchers often use tau as their biomarker to measure and gauge the progress of Alzheimer’s in both animal models and in people.
Possible Cause and Effect
The authors also cautioned the readers that their study design cannot demonstrate the causal relationship between using a particular drug and the risk of the disease. They cannot fully eliminate the possibility that there may be hidden confounding factors that have an impact on both the risk of the disease and also the likelihood of sildenafil use.
The probable confounding factors were not included in the insurance. Education level and socioeconomic status were also not taken into account. However, there was no crucial and impacting difference in total annual prescription costs between sildenafil users and nonusers. This somewhat hints at how both groups did were not that different in terms of wealth status.
The authors also considered their lab results and believe that conclusion the conclusion they came up with means that sildenafil is a possible treatment. “[W]e don’t think the socioeconomic status will drive our findings, as we further validated our findings in [Alzheimer’s] patient-derived [nerve cell] models as well,” senior author Feixiong Cheng, Ph.D., said to MNT. The authors further note that some of the details were not found in the insurance data such as genetic details, or whether or not the claimants had a particular version of the apolipoprotein E gene, which increases the risk of the disease as well as their responses to treatment.
It’s also important to note that healthcare professionals mostly prescribe sildenafil to men. This means that the study did not determine the medicine’s possible benefits in females. “While the researchers did look at the effect of sildenafil on females, there isn’t enough information to be able to accurately draw conclusions about its effect in females, which account for the majority of Alzheimer’s cases worldwide,” explained Dr. Kohlhaas.
“Importantly, this research doesn’t prove that sildenafil is responsible for reducing dementia risk or that it slows or stops the disease,” she further said. “The only way to test this would be in a large-scale clinical trial measuring sildenafil’s effects against the usual standard of care.”
The authors of the study then came up with a conclusion. They said, “Taken together, the association between sildenafil usage and decreased incidence of [Alzheimer’s disease] does not establish causality or its direction, and our results, therefore, warrant rigorous clinical trial testing of the treatment efficacy of sildenafil in patients with [Alzheimer’s disease], inclusive of both sexes and controlled by placebo.”
“We are planning a mechanistic trial and biomarker-guided phase 2 trial in the next step to further verify [the] clinical benefit of sildenafil in early [Alzheimer’s disease] patients,” Dr. Cheng also said to MNT.
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