May 25, 2012
New Gene Discovery Could Lead To Non-Hormonal Contraceptive For Men
Male contraception may be a possibility thanks in part to a discovery of a new key reproductive gene critical for production of healthy sperm, suggests Scottish scientists credited with the discovery.
Researchers from Edinburgh University are hopeful their study, which involved mice, could lead to a new type of male birth control that doesn´t disrupt the production of hormones, something which often causes side effects such as mood swings.
The researchers found that a gene known as Katnal1 is critical in enabling sperm to mature. Scientists believe by regulating this gene they could prevent sperm from maturing, making them infertile without altering hormones. The team found that Katnal1 in mice was vital for the final stages of sperm production.
Producing a drug for male birth control would be significant, especially since the only alternatives currently available for men are condoms or irreversible vasectomy.
“If we can find a way to target this gene in the testes, we could potentially develop a non-hormonal contraceptive,” said Dr. Lee Smith, Reader in Genetic Endocrinology at the University of Edinburgh's Centre for Reproductive Health. “The important thing is that the effects of such a drug would be reversible because Katnal1 only affects sperm cells in the later stages of development, so it would not hinder the early stages of sperm production and the overall ability to produce sperm.”
Using male mice, the researchers found that by altering them not to have the Katnal1 gene made them infertile. Katnal1 is needed to regulate microtubules, which form part of the cells that support and provide nutrients in sperm development. Breaking down and rebuilding the microtubules enables the sperm cells to move within the testes as they mature. Katnal1 is an essential controller of this process.
“Many cases of male infertility remain unexplained and as such Katnal1 is a good example of a previously unknown gene that when mutated causes male infertility,” said Smith. “This study could help identify the causes underlying unexplained male infertility.”
Scientists are hopeful that they can replicate their mice experiments in men without causing lasting damage. But it could be “relatively difficult” to do as the protein lives inside cells, said Smith. However, he noted, there was “potential” to find something else that the protein can work with, which might be an easier target.
Dr Allan Pacey, senior lecturer in andrology at the University of Sheffield, said there was “certainly a need” for a non-hormonal contraceptive for men.
“The key in developing a non-hormonal contraceptive for men is that the molecular target needs to be very specific for either sperm or other cells in the testicle which are involved in sperm production,” he told BBC News. “If they are not, then such a contraceptive could have unwanted side effects on other cells and tissues in the body and may even be dangerous.”
“The gene described by the research group in Edinburgh sounds like an exciting new possible target for a new male contraceptive, but it may also shed light on why some men are sub-fertile and why their sperm does not work properly,” said Pacey, who was not part of the study.
The researchers, publishing their work in the journal PLoS Genetics, also said there was a possibility of introducing a DNA sequence that could permanently block Katnal1, causing permanent sterility, which they dubbed: a “genetic vasectomy.”
But any treatments developed through their study would be at least five to ten years from reality, they noted.
The Edinburgh University study was funded by the Medical Research Council.