Trapping sperm in semen's natural gel could lead to new contraceptive


Date:
February 7, 2022
Source:
Washington State University
Summary:
A discovery that blocks the normal transition of semen from a
thick gel to a liquid shows promise for development of a new form
of non-hormonal, over-the-counter contraception. A research team
recently showed that blocking a prostate-specific-antigen in human
ejaculate samples caused the semen to remain in its thick gel form,
trapping the majority of the sperm.



FULL STORY ==========================================================================
A discovery that blocks the normal transition of semen from a thick gel
to a liquid shows promise for development of a new form of non-hormonal, over-the- counter contraception.


==========================================================================
A Washington State University-led research team recently showed that
blocking prostate-specific-antigen in human ejaculate samples caused
the semen to remain in its thick gel form, trapping the majority of the
sperm. Normally, the semen will liquefy, allowing sperm to swim through
the female reproductive system to fertilize an ovum or egg. The discovery
is able to stop that process and detailed in the journal Biology of Reproduction.

"Our goal is to develop this into an easily accessible female
contraceptive that would be available on-demand, meaning women could go
buy it off the shelf," said senior author Joy Winuthayanon, associate
professor and director of WSU's Center for Reproductive Biology. "It
could be used in combination with a condom to lower the failure
rate significantly." Currently over-the-counter contraceptives such
as condoms and spermicides have an average 13% to 21% failure rate,
the study authors noted. Hormonal-based contraceptives such as IUDs
and birth control pills have lower failure rates, but they can have
some side-effects and are not always easily available or affordable --
which may be one reason why worldwide the unintended pregnancy rate is currently 48%, according to recent global health research.

The WSU team has been working on this contraceptive method since 2015
after it was accidentally discovered that some of the female mice in a different reproductive study could not get pregnant; upon investigating further, the researchers discovered the male's semen was staying in solid
form. The researchers then tried stopping the semen liquification process
in mice on purpose, and using a non-specific protease inhibitor called
AEBSF, they were able to disrupt sperm movement and reduce fertility in
mice, detailing their results in an earlier Biology of Reproduction paper.

In the current study, the research team worked to see if they could
translate those results to human samples. They found that AEBSF did have
a contraceptive effect, but it was unclear whether this was simply due to
its toxicity. They then used an antibody to target the prostate-specific antigen or PSA in human sperm. They chose PSA because it is the primary
active protein in liquefication and secreted in large quantities from
the prostate gland, which is present in humans but not in mice.

Typically, after ejaculation the PSA acts on the gel-forming proteins
called semenogelins, explained first author Prashanth Anamthathmakula,
who worked as a WSU post-doctoral fellow on the project.

"The semenogelins create a gel-like network with a fine mesh of proteins
which traps the sperm. The PSA cleaves that mesh and the sperm become
free," said Anamthathmakula, who is now a senior research scientist at University of Missouri-Kansas City. "Using a PSA inhibitor, an antibody,
we showed that we could block that liquefaction." The next step is to
identify more specific small molecule inhibitors that would effectively
prevent PSA's ability to liquefy semen without any detrimental side
effects. The researchers noted that current spermicides have been shown to lower the natural vaginal barriers against sexually transmitted diseases
like HIV. By targeting the liquefaction process of the semen itself,
this advance could avoid that type of toxicity, but more research needs
to be done.

"It is a bit of a long process because we don't want off-target
effects," said Winuthayanon. "If we are going to develop this into
the contraceptive product, it may be something that women would use
often, so we want something that is safe and has no unintended effects." ========================================================================== Story Source: Materials provided by Washington_State_University. Original written by Sara Zaske. Note: Content may be edited for style and length.


========================================================================== Related Multimedia:
* Human_semen_treated_with_AEBSF_to_block_semen_liquefaction ========================================================================== Journal Reference:
1. Prashanth Anamthathmakula, Jeffery A Erickson, Wipawee Winuthayanon.

Blocking serine protease activity prevents Semenogelin degradation
leading to Hyperviscous semen in humans. Biology of Reproduction,
2022; DOI: 10.1093/biolre/ioac023 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220207100105.htm

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