Viagra as a Therapy for Heart Failure

Viagra as a Therapy for heart Failure: Effectiveness on Male vs Female

David Chen
17 May 2014

John Hopkins University School of Medicine
Published: 16 May 2014
http://medicalxpress.com/news/2014-05-gender-differences-impact-viagra-therapy.html


Summary:
          When we think of Viagra, we don't think of a treatment for heart failure. We think of those awkward advertisements... Or what the drug was made for, erectile dysfunction. However, within the last decade, scientists have realized another use for Viagra. Sildenafil, the active ingredient in Viagra, can help with heart problems. Sildenafil, when taken, can activate an enzyme that causes a protein called "titin" to relax. This protein is responsible for the elasticity of a cell, and in muscle tissue, it can often cause stiffening. In Viagra's normal application, it dilates the blood vessels, leading to increased blood flow to the penis. However, with further testing, Takimoto, an assistant professor of medicine and a researcher at the Heart and Vascular Institute at John Hopkins, and his team discovered something peculiar between male and female mice models. All of the mice recieved cardiac remodeling. The effectiveness of Sildenafil on females were different from the males. Upon further research, scientists discovered that the hormone estrogen played a role in interacting with Sildenafil. As of now, it appears to help in repairing the heart muscle. Takimoto says this could be an explanation for why a Sildenafil based drug: "RELAX", does not work effectively, as most of its female participants were 70 or older, when menopause had already struck, and estrogen was lower.

Connection:
          This article has several connections to what we are learning in biology. Firstly, the main way Sildenafil works is by activating an enzyme, which interacts with a protein. This connects with our unit where we learned about enzymes and proteins. Also, titin connects with how muscles work, as it adds on to our knowledge about how the basic units of muscles, sarcomeres, work. Second, this connects with the circulatory system, in our current unit about the human body. Specifically, it connects with heart failure, which is a condition brought on by many of the diseases explored by the Circulatory Presentation group (I'm in it). Third, the hormone estrogen will connect with a later unit that we will go over, in which we explore the hormones of the body.