One in ten men in the Western countries suffers from erectile dysfunction and the inability of the penis varies greatly in severity.

The causes also vary greatly and even if many treatments have been developed, including using drugs like Viagra, Cialis and Levitra, not all types of ED respond to medication, like that resulted after a prostate cancer surgery.
Now researchers at the University of Pittsburgh, led by Dr Joseph Glorioso, are on the way of developing a gene therapy treatment for ED.

Human and animal trials are positive and gene therapy could be efficient far longer than pills used just before sex, which also spoil spontaneity. The human trials involved injections into the penis, a fact seen by some experts as undesirable. The gene therapy was tested in rats with ED caused by nerve damage. The technique employs the herpes simplex virus as a carrier of a gene called GDNF or another, named neurturin, both boosting nerve growth.

Rats experiencing the gene therapy displayed significant recovery and regained normal penile function after four weeks. Meanwhile, human trials were made by a team at Wake Forest University, helped by Dr Arnold Melman from the Albert Einstein College of Medicine. The 11 volunteers displayed few side effects, despite the injection into the penis. The gene therapy improved erectile function in some of the men.

"This is an exciting field of research because current treatments for men with erectile dysfunction, whether pills or minimally invasive therapies, must be used 'on demand', thereby reducing the spontaneity of the sexual act." said Melman.

The Wake Forest therapy is based on inserting small DNA stretches into cells to boost the production of proteins which relax smooth muscle cells and get an erection.

"The gene therapy might be appealing to some men for whom other treatments had failed, but predicted many men would be reluctant to have a shot in the penis. Many men with ED also had underlying medical disease, such as high blood pressure, raised cholesterol or diabetes, and that this should also be treated. And there is a good argument for treating ED as a chronic disease too," said Dr Geoff Hackett, president of the British Society for Sexual Medicine.