Don’t judge sperm by its cover

man with glass

Not all sperm are created equally. For a long time, doctors have looked for the malformed and less motile to know which sperm to avoid for ICSI and IVF procedures. However, that doesn’t guarantee the best DNA integrity. It might look good on the outside, but it’s what’s on the inside that counts.

Researchers at the Yale School of Medicine have discovered a technique to pluck out the sperm with the best DNA integrity thus improving male fertility. Gabor Huszar, MD, director of the Sperm Physiology Lab and senior research scientist in the Department Obstetrics, Gynecology and Reproductive Sciences at Yale, explained that up until now, if a man had an abundant amount of sperm and they all seemed appropriately active, then he was good to go.

But doctors were making a big assumption that these sperm actually could get the job done. There was no information as to whether or not the sperm would be successful hooking up with the female gamete. In a natural setting, the ovum actually selects the best sperm by letting it in. In vitro fertilization doesn’t give the ovum many choices and with ICSI, no choice at all. “We have now found a biochemical marker of sperm fertility so that we can select sperm with high genetic integrity,” Huszar said.

The idea is that sperm which binds to hyaluronic acid will have high DNA integrity. Researchers took sperm samples and allowed them to bind. They were then isolated and the DNA chain was compared to the original sperm in semen. The team was able to then identify the best sperm and confirm their results.

“The sperm with fragmented DNA work like scratched CDs,” Huszar explained. “They seem to be operational, but when you play them, some of the information is missing. These damaged sperm may also carry chromosomal aberrations that could be related to genetic diseases.”

Huszar continued, “When sperm is selected with hyaluronic acid binding, they are of comparable, if not better, overall quality then sperm chosen by the oocyte in the natural fertilization process.” This sounds a bit like eHarmony for reproductive material - are there perhaps 29 dimensions of compatibility they are also testing for?

Source: Yale University, Science Daily


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