Only The Best

New research shows that an easy-to-perform lab test can help isolate healthy, normal sperm cells with 99% accuracy from those sperm that suffer from DNA damage.

The lab test employs a chemical that is contained within human egg cell membranes to separate functional sperm from their non-functioning counterparts. The test has already passed muster with the Food and Drug Administration (FDA) and can be used in conjunction with in vitro fertilization (IVF). It is believed this new technology will raise conception success rates with IVF by some 20%-30%. This is according to the lead developer of this technique, Gabor Huszar, who is a senior researcher at Yale Medical School's Department of Obstetrics, Gynecology, and Reproductive Sciences.

A Choice

Huszar says that common tests for male fertility train a spotlight on sperm count and motility. But these tests fail to take into account that sperm and eggs both produce receptors along their surfaces that are needed for proper bonding. As Huszar puts it, "The sperm and the egg choose each other."

In ICIS however, it is the doctor who chooses the sperm that will fertilize the egg. He injects just one sperm cell into an egg while viewing his work through a microscope. The doctor can't tell which sperm will be free of DNA damage just by assessing sperm counts and sperm motility. Neither of these measures ensures that the sperm the physician chooses will be capable of fertilizing an egg.

Should the doctor choose a poor quality sperm cell, the result will be a failure to fertilize. Should fertilization be achieved in spite of the poor quality of the sperm, the result is likely to be genetic problems carried to the embryo by the sperm which might lead to miscarriage or developmental issues.

Natural Component

Huszar's team used hyaluronic acid to separate good quality sperm from damaged sperm. This acid is a natural component of the egg cell membranes and sperm are attracted to bind to this compound, though not all sperm are capable of successful bonding. The scientists then treated the sperm cells of the 50 participants with a dye that turns sperm cells with intact DNA green and sperm cells with damaged DNA red.

The scientists separated the bound sperm from the unbound sperm 15 minutes later. The results were remarkable: over 99% of the bound sperm had taken on a green color and were thus deemed free of DNA damage, while only half of the unbound sperm had taken on the green color. This proves that the sperm in this study that were able to bind to the hyaluronic acid were of high quality, such as would be the case in natural fertilization during which the egg would choose the best sperm. Huszar says that the method his team devised for the purpose of sperm selection proved itself the first time out.

Some fertility clinics are already using this method to choose the sperm to be used in IVF and ICSI treatments. But hyalonic acid testing can also be employed to help diagnose infertility by assessing the percentage of sperm that cannot bind and fertilize.

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