The stem cell therapy involves injecting the patients' own stem cells - derived from abdominal fat cells - into the erectile tissue of the penis.
Lead researcher Dr. Martha Haahr, of Odense University Hospital in Denmark, and colleagues found that within 6 months of the procedure, 8 of the 21 men treated were able to engage in spontaneous sexual intercourse.
Erectile dysfunction (ED) is a condition whereby a man has difficulties getting or maintaining an erection in order to engage in sexual intercourse.
According to the National Institute of Diabetes and Digestive Kidney Diseases, around 12 percent of men under the age of 60, and 22 percent of men aged between 60 and 69, have ED.
High blood pressure, diabetes, heart disease, chronic kidney disease, and prostate surgery are some of the physical conditions that can cause ED. Psychological issues - such as anxiety, stress, depression, and low self-esteem - can also contribute to ED.
Current treatments for ED include PDE5 inhibitors (such as Viagra), penile implants, and injections. However, Dr. Haahr and team note that all of these therapies can have significant side effects.
As a result, researchers are on the hunt for alternative treatments for ED, and stem cell therapy has emerged as a promising candidate in animal trials.
Sexual function improvements evident a year after treatment
In their phase I trial, Dr. Haahr and colleagues tested stem cell therapy on 21 men who had ED as a result of undergoing radical prostatectomy for prostate cancer. None of the men had responded to standard medical treatment for ED.
For the stem cell procedure, abdominal fat cells were extracted from each man through liposuction. Stem cells were then isolated from the fat cells and injected into the corpus cavernosum of the penis - the spongy tissue that normally becomes filled with blood during an erection.
Before the stem cell procedure and 6 and 12 months after, the participants' erectile function was assessed using the International Index of Erectile Function (IIEF) questionnaire. An IIEF score of 5-7 represents severe erectile dysfunction, 12-16 is mild to moderate erectile dysfunction, and 22-25 is no erectile dysfunction.
All 21 men saw their erectile function improve with stem cell therapy: their IIEF score increased from 6 prior to treatment to 12 at 6 months after treatment.
Eight of the men reported that they had been able to engage in spontaneous sexual activity 6 months after stem cell therapy, and this outcome remained evident at 12 months after treatment. These men saw their IIEF score rise from 7 to 14 with stem cell therapy.
"What we have done establishes that this technique can lead to men recovering a spontaneous erection - in other words, without the use of other medicines, injections, or implants," says Dr. Haahr.
Stem cell therapy 'could be a long-term solution' for ED
Although the study findings are preliminary, the team says that they show promise for stem cell therapy as an effective treatment strategy for ED.
"We are the first to use a man's own fat stem cells as a treatment for erectile dysfunction in a clinical trial. The technique has been trialed in animal work, but this is the first time stem cell therapy has allowed patients to recover sufficient erectile function to enable intercourse," says Dr. Haahr.
"We are pleased with the preliminary outcomes, especially as these men had previously seen no effect from traditional medical treatment and continue to have good erectile function after 12 months follow-up, indicating that this might be a long-term solution.
This suggests the possibility of therapeutic options for patients suffering from erectile dysfunction from other causes. But we need to remember that this is a small trial, with no control group. We're still some time away from a clinically available solution."
Dr. Martha Haahr
The researchers are now in the process of initiating a phase II trial to further investigate the safety and efficacy of stem cell therapy for ED.