A new gel-based vasectomy has proven effective in a group of monkeys, raising hopes it could one day provide a permanent but easily reversible male contraceptive option in humans.
Vasalgel works by plugging the vas deferens, the two tiny tubes that convey sperm into a male's semen, researchers said.
The gel "doesn't break down. It just sets up a little more, and sticks where you inject it," said lead researcher Catherine VandeVoort. She's a professor of obstetrics and gynecology with the University of California, Davis School of Medicine. Sixteen male rhesus macaque monkeys injected with the non-hormonal gel have proven incapable of reproduction, according to the study findings. No females have become pregnant in the males' presence, even though they were housed together for at least one breeding season -- about 6 months.
"We're over two years in a lot of these males we injected with this, and so far they've all remained infertile," said VandeVoort. "We know that because we check the parentage of every baby that's born at the primate center." VandeVoort is also a scientist with the California National Primate Research Center at UC Davis.
Traditional vasectomies either sever, crush or tie off the vas deferens, causing tissue damage that can be difficult to reverse, VandeVoort said. But researchers hope to revise the Vasalgel plug to the point where a simple solution of water and baking soda would flush it out of the vas deferens, easily restoring a man's fertility, said study co-author Elaine Lissner. The gel plug has been successfully flushed out of male rabbits in animal testing, but reversibility has not yet been perfected in primates, said Lissner, founder and trustee of the Parsemus Foundation, the nonprofit group funding development of the gel.
The focus of the current study was to see whether Vasalgel would effectively prevent conception, Lissner and VandeVoort said. "This tells us whatever challenges we face, the bottom line is it has worked and been safe in animals similar to humans," Lissner said. The Parsemus Foundation, based in Berkeley, Calif., funded the primate study. The group is now looking for funding to move to the next step in primates, which will be to test reversibility. Researchers also are preparing for human trials to test whether Vasalgel would work as a contraceptive in men, Lissner said. The Parsemus Foundation hopes to start enrolling men for a clinical trial by the end of the year.
HealthDay
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Editor : M. Shamsur Rahman
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Editor : M. Shamsur Rahman
Published by the Editor on behalf of Independent Publications Limited at Media Printers, 446/H, Tejgaon I/A, Dhaka-1215.
Editorial, News & Commercial Offices : Beximco Media Complex, 149-150 Tejgaon I/A, Dhaka-1208, Bangladesh. GPO Box No. 934, Dhaka-1000.