Gene therapy may relieve impotence

NEW YORK (Reuters Health) - A small pilot study shows that gene therapy might help men with erectile dysfunction.

The gene in question is dubbed hSlo (for the human slowpoke gene), which encodes a protein that relaxes smooth muscle and allows blood flow into the penis, researchers report in the medical journal Human Gene Therapy. In order for the gene to be administered to patients, it is incorporated into a packet of DNA called a plasmid.

The results of the early-stage trial, lead investigator Dr. Arnold Melman told Reuters Health, "suggest that the technology worked. We have shown that we could give a safe vector, naked DNA, and the hSlo gene and obtain an expected physiological response without transfer-related side effects."

Melman, at Montefiore Medical Center and Albert Einstein College of Medicine, the Bronx, New York and colleagues studied 11 patients with erectile dysfunction, which was associated with diabetes or cardiovascular disease in about half of the cases. The subjects were given a single injection ranging from 500 to 7500 micrograms of the hSlo plasmid into the corpus cavernosum of the penis and monitored for 24 weeks.

No serious adverse effects were seen, and patients given the two highest doses had sustained improvements in erectile function. One patient at each of these dosing levels reported improvements that were highly clinically significant and were maintained over the whole study period.

The researchers note that the goal of the study was to establish the safety of the procedure and no conclusions about efficacy can be drawn, although the results are highly encouraging. The "final proof will be obtained in the larger placebo-controlled trials to follow," Melman said.

SOURCE: Human Gene Therapy, December 2006.