Can a hair loss drug prevent heart disease?

Drug development is expensive and subject to many uncertainties. Drug repurposing reduces time and costs by identifying new uses for drugs that are already approved or under study by the U.S. Food and Drug Administration. The FDA approved finasteride in 1992 under the brand name Proscar to treat benign prostatic hyperplasia in men and again in 1997 under the brand name Propecia to treat male pattern baldness.

Researchers at the University of Illinois Urbana–Champaign, U of I, recently discovered another potential use of finasteride: the prevention of cardiovascular disease. In a study published in the Journal of Lipid ResearchThe team believes that finasteride reduces the risk of heart disease by lowering cholesterol levels.

The researchers examined the effects of finasteride on male mice and analyzed data from men who participated in the National Health and Nutrition Examination Survey (NHANES) between 2009 and 2016.

Finasteride is a 5-alpha-reductase inhibitor that prevents the conversion of testosterone to dihydrotestosterone or DHT, an active metabolite that plays a crucial role in the formation of the male reproductive organs, hair growth and prostate growth.

Donald Molina, a doctoral student at the U of I and lead author of the study, explained that low testosterone levels in men are associated with a higher risk of cardiovascular disease.

“Because the drug affects testosterone levels, we thought there might be a link between the drug and heart disease,” he said. “That was our starting point; we looked at how finasteride affects lipid profiles in humans.”

The team first analyzed data stored at NHANES and found that taking finasteride was associated with a reduction in total cholesterol and low-density cholesterol.

“These results encouraged us to conduct animal studies,” Molina said.

The researchers used male mice with a genetic predisposition to atherosclerosis, a leading cause of heart disease. They fed the mice a high-fat, high-cholesterol diet for 12 weeks and gave them finasteride in four increasing doses. They monitored cholesterol and other lipid levels and examined gene expression and the lipid metabolome.

Mice treated with finasteride had lower cholesterol levels, delayed progression of atherosclerosis, lower plasma triglycerides and less liver inflammation.

Jaume Amengual, an associate professor at the University of Illinois and lead author of the study, said the team hypothesizes that the liver breaks down more lipids in the presence of finasteride.

“The liver burns more fat,” said Amengual. “We can also link our results to fatty liver disease. When you eat a poor diet, a lot of fat accumulates in your liver, your liver becomes inflamed and eventually develops cirrhosis and even cancer. So in our experiment, we see a decrease in fat content in the liver and reduced liver inflammation. Finasteride not only reduced plasma cholesterol levels, but also improved liver function in these mice.”

To support these findings, researchers need a detailed analysis of finasteride's effects on a statistically relevant population and metabolic side effects, such as gut microbiota levels, as well as interactions with other drugs that target cholesterol synthesis or absorption.

“One of the reasons I became interested in this drug in the first place is that I have been taking this drug for hair loss since I was 20 years old,” Amengual said. “Despite the limitations, our study provides a foundation for repurposing finasteride to prevent cardiovascular disease.”