Scientists using gene transfer to treat erectile dysfunction say that the technique shows promising results. "In the small pilot study, this new therapy was well tolerated and safe," said George Christ, senior researcher at the Institute for Regenerative Medicine at Wake Forest University School of Medicine. "It provides evidence that gene transfer is a viable approach to treating erectile dysfunction and other diseases involving smooth muscle cells." Writing about their research in the journal Human Gene Therapy, the researchers explained that unlike traditional gene therapy, the gene transfer approach they used does not change the DNA or genetic code of cells. Instead, small pieces of DNA reach the nuclei of cells and this causes them to increase production of particular proteins. These proteins help relax smooth muscle cells, the type of muscle found in the penis. When relaxed, the tissue allows the penis to fill with blood and become erect.
The new technique may provide an important alternative for the estimated 30-40 percent of men with erectile dysfunction who cannot take oral medications like Viagra. Encouragingly, a single gene transfer treatment provided erectile improvement that was maintained through the 6 months of study.
The men in the study ranged from 42 to 80 years of age, with around half suffering from diabetes or cardiovascular disease, both of which can interfere with the ability of smooth muscle cells to relax. The main aim of the study was to determine the safety and tolerability of the new therapy, however, the results also showed that at the highest doses, the men reported significant improvements in erectile function.
The treatment consisted of injecting DNA segments into the corpus cavernosum, the expandable tissue along the length of the penis that fills with blood during erection. The effectiveness of the treatment was measured using the International Index of Erectile Function scale, a questionnaire that is commonly used to measure erectile dysfunction. The men who received the highest doses had apparent sustained improvements in erectile function as measured by the questionnaire.
While the initial results from this small study are very encouraging, the researchers caution that a larger study, that includes a control group treated with a placebo, is needed to confirm the safety and effectiveness of the treatment.
Based on material from Wake Forest University Baptist Medical Center
