News | Blocking Semen Liquefaction May Lead to a Nonhormonal Contraceptive
A Washington State University (WSU)-led study found that blocking semen from changing from a gel to a liquid can trap sperm and prevent them from entering the female reproductive tract to fertilize an egg. Published in Biology of Reproduction, the findings offer a promising direction for a new nonhormonal, over-the-counter contraceptive.
Blocking semen liquefaction restricts sperm movement
The researchers found that when prostate-specific antigen (PSA) activity in human semen was blocked, the semen remained gel-like and most sperm were trapped and unable to swim toward the egg. Normally, PSA breaks down the semen protein semenogelin, allowing sperm to move freely after ejaculation and fertilize an egg.
“Our goal is to translate this finding into an on-demand contraceptive that women can obtain directly from a pharmacy, like condoms.”
—Associate Professor Joy Winuthayanon, senior author and Director of the WSU Center for Reproductive Biology
Over-the-counter methods such as condoms and spermicides have failure rates of about 13%–21%. Hormonal methods such as oral contraceptives and intrauterine devices are more effective but may involve side effects, cost, and access barriers. Global research indicates that about 48% of pregnancies are unintended, creating an urgent need for nonhormonal contraception.
An unexpected discovery changed the research direction
The research began with an incidental finding in 2015. During another mouse reproduction experiment, the WSU team noticed that some female mice could not become pregnant because the males’ semen did not liquefy. Researchers then used the nonspecific protease inhibitor AEBSF to block semen liquefaction in mice and reduce pregnancy rates. Those early findings were previously published in the same journal.
In the latest study, the team extended the experiment to human semen samples for the first time. They confirmed that AEBSF had contraceptive effects, but its potential toxicity made it unsuitable for human use. They then used an antibody against PSA to inhibit the protein specifically, achieving more precise and safer inhibition of semen liquefaction.
“PSA is the main enzyme responsible for semen liquefaction. It cuts through the protein network in semen and releases sperm. With a PSA inhibitor, we demonstrated that this process can be stopped.”
—Dr. Prashanth Anamthathmakula, first author and now Senior Research Scientist at the University of Missouri–Kansas City
Toward safe, affordable nonhormonal contraception
The team’s next step is to identify more specific small-molecule inhibitors that suppress PSA without affecting other body systems.
“This will be a long process. We hope to develop a product that is safe, has no side effects, and is suitable for frequent use.”
—Associate Professor Winuthayanon
Some commercial spermicides may weaken the vagina’s natural barrier and increase the risk of sexually transmitted infections such as HIV. This strategy acts directly on semen rather than the vaginal environment and may avoid those toxicity concerns.
The research offers a novel contraceptive approach: preventing fertilization by changing the physical properties of semen rather than altering hormone levels. If a safe and effective formulation is developed, it could give women an over-the-counter option and reshape contraception worldwide.
News | Blocking Semen Liquefaction May Lead to a Nonhormonal Contraceptive
News | Blocking Semen Liquefaction May Lead to a Nonhormonal Contraceptive
A Washington State University (WSU)-led study found that blocking semen from changing from a gel to a liquid can trap sperm and prevent them from entering the female reproductive tract to fertilize an egg. Published in Biology of Reproduction, the findings offer a promising direction for a new nonhormonal, over-the-counter contraceptive.
Blocking semen liquefaction restricts sperm movement
The researchers found that when prostate-specific antigen (PSA) activity in human semen was blocked, the semen remained gel-like and most sperm were trapped and unable to swim toward the egg. Normally, PSA breaks down the semen protein semenogelin, allowing sperm to move freely after ejaculation and fertilize an egg.
“Our goal is to translate this finding into an on-demand contraceptive that women can obtain directly from a pharmacy, like condoms.”
—Associate Professor Joy Winuthayanon, senior author and Director of the WSU Center for Reproductive Biology
Over-the-counter methods such as condoms and spermicides have failure rates of about 13%–21%. Hormonal methods such as oral contraceptives and intrauterine devices are more effective but may involve side effects, cost, and access barriers. Global research indicates that about 48% of pregnancies are unintended, creating an urgent need for nonhormonal contraception.
An unexpected discovery changed the research direction
The research began with an incidental finding in 2015. During another mouse reproduction experiment, the WSU team noticed that some female mice could not become pregnant because the males’ semen did not liquefy. Researchers then used the nonspecific protease inhibitor AEBSF to block semen liquefaction in mice and reduce pregnancy rates. Those early findings were previously published in the same journal.
In the latest study, the team extended the experiment to human semen samples for the first time. They confirmed that AEBSF had contraceptive effects, but its potential toxicity made it unsuitable for human use. They then used an antibody against PSA to inhibit the protein specifically, achieving more precise and safer inhibition of semen liquefaction.
“PSA is the main enzyme responsible for semen liquefaction. It cuts through the protein network in semen and releases sperm. With a PSA inhibitor, we demonstrated that this process can be stopped.”
—Dr. Prashanth Anamthathmakula, first author and now Senior Research Scientist at the University of Missouri–Kansas City
Toward safe, affordable nonhormonal contraception
The team’s next step is to identify more specific small-molecule inhibitors that suppress PSA without affecting other body systems.
“This will be a long process. We hope to develop a product that is safe, has no side effects, and is suitable for frequent use.”
—Associate Professor Winuthayanon
Some commercial spermicides may weaken the vagina’s natural barrier and increase the risk of sexually transmitted infections such as HIV. This strategy acts directly on semen rather than the vaginal environment and may avoid those toxicity concerns.
The research offers a novel contraceptive approach: preventing fertilization by changing the physical properties of semen rather than altering hormone levels. If a safe and effective formulation is developed, it could give women an over-the-counter option and reshape contraception worldwide.
Source:
Collected online