Two
new studies suggest that a type of gene therapy may be a safe and effective
treatment for erectile dysfunction.
Erectile
dysfunction, or ED, is the repeated inability to maintain an erection. An
estimated 15 to 30 million (20-40 percent) of American men suffer from ED. For
every 1,000 men between 40 and 69 years of age in the United States, 26 new
cases of ED are diagnosed every year. Worldwide, ED affects over 150 million
men.
Although
ED is more common in men older than 65, it can occur at any age. An occasional
episode happens to most men and is normal. But as men age, it is also normal to
experience changes in erectile function. Erections may take longer to develop,
may not be as rigid or may require more direct stimulation to be achieved. Men
may also notice that orgasms are less intense, the volume of ejaculate is
reduced and recovery time increases between erections.
ED
may be a result of lifestyle choices, such as smoking, being overweight, eating
unhealthy foods or avoiding exercise. It may also be psychological or result
from physical conditions, such as diabetes, vascular disease, surgery or
trauma, neurological conditions, hormone disorders and Peyronie's disease.
A
wide variety of options exist for ED including psychological counseling,
medications, mechanical devices and surgery. The cause and severity of the ED
are important factors in determining the best treatment or combination of
treatments for the individual. If ED is the result of a medical condition, the
cost of treatment may be covered by insurance.
The
researchers studied the effectiveness of a unique, locally-administered gene
transfer technique for treating ED. The therapy consisted of a plasmid, or
circular DNA construct, containing the gene for the Maxi-K protein.
This
protein makes up the Maxi-K ion channel, which is a potassium channel;
activation of this channel is critical for relaxing the vasculature and allowing
an erection to take place.
The
plasmid was designed to express Maxi-K in vascular smooth muscle cells and was
injected into men with moderate to severe ED.
According
to the study authors, human tests have primarily focused on safety. Animal
tests have demonstrated that the therapy increases erectile function and other
measures of sexual behavior.
The
researchers suggested that men with ED could get the gene therapy treatment
twice a year, based on human and animal research showing that the treatment
lasts for up to six months.
They
also observed that the gene therapy may work synergistically with drugs such as
Viagra® and Cialis®, allowing patients to take lower doses of these
medications.
The
gene therapy appears safe; in humans no transfer-related adverse events were
reported during two years of follow up. The study authors noted that unlike
conventional oral therapies for ED, Maxi-K therapy does not require prior
planning thereby enabling sexual spontaneity; also, it can be used by men taking
heart medications.
The
authors concluded that Maxi-K gene therapy may be a safe and effective future
option for men whose ED is not treatable with oral therapy.
Some
tips for preventing ED include limiting or avoiding the use of alcohol and
other recreational drugs (marijuana, cocaine), quitting smoking, exercising
regularly (at least 30 minutes daily), reducing stress, getting enough sleep
(eight hours a night), dealing with anxiety or depression (through counseling
and medication) and seeing a doctor for regular checkups and medical screening
tests. Although it may be uneasy to talk about, ED is a treatable condition and
should be discussed with a healthcare professional.
