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Sperm Test Offers Clues to Male Infertility

It can detect protein linked to defective sperm

WEDNESDAY, July 31, 2002 (HealthDayNews) -- Researchers from the University of Missouri-Columbia may soon be able to offer hope to couples struggling to conceive a child.

That hope comes in the form of a new test that can identify sperm with high levels of a protein believed to be found in defective sperm, the researchers report in the current issue of Human Reproduction.

"This study provides evidence that increased levels of this protein are linked to infertility," says the study's lead author, Peter Sutovsky, an assistant professor of animal sciences and clinical obstetrics and gynecology at the University of Missouri-Columbia.

Sutovsky says as many as 15 percent of all couples trying to have a baby in the United States are infertile. Male infertility is responsible for about half the cases, he adds.

But in 20 percent of all infertility cases, the cause is never discovered, according to Sutovsky.

Those are the cases where he thinks this new test will be most useful.

In the current study, the researchers tested sperm samples from 13 men. Eight were fertile men and five were infertile due to a disorder known as stump tail syndrome. Tails are the "motors that drive the sperm," says Sutovsky. So, when sperm tails are abnormally short -- as they are in stump tail syndrome -- the sperm have no motility, and therefore are unable to fertilize an egg.

Sutovsky and his colleagues found that sperm from the infertile men had much higher levels of a protein called ubiquitin than did the sperm of the fertile men.

The researchers hope that by testing for ubiquitin, they will be able to detect abnormal sperm that have no obvious defects. Sutovsky says the test could be particularly useful for couples undergoing in vitro fertilization or intracytoplasmic sperm injection -- the procedure in which a single sperm is injected into an egg.

Testing for ubiquitin could help improve the success rates of those procedures because only healthy sperm would be selected.

Sutovsky says the cost of the test won't be that high. But it will be six months or more before it might become available.

Michael Stahler, director of the In Vitro Fertilization Lab at William Beaumont Hospital in Royal Oak, Mich., feels that while the test may prove useful in the future, much more research remains to be done.

"This study is an interesting beginning, but there were not a lot of patients involved," he says. "It may eventually prove to be a marker that explains some unexplained infertility."

What To Do

For more information on male infertility, visit the Yale Center for Reproductive Medicine and Infertility, or The Endocrine Society.

SOURCES: Peter Sutovsky, Ph.D., assistant professor of animal sciences and obstetrics and gynecology, University of Missouri-Columbia; Michael Stahler, Ph.D., director, In Vitro Fertilization Lab, William Beaumont Hospital, Royal Oak, Mich.; August 2002 Human Reproduction
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