A new test named Cap-Score Male Fertility Assay could measure male fertility. The study published in the journal Molecular Reproduction and Development suggests that urologists may also use the Cap-Score to evaluate how different treatment regimens, such as nutritional supplements or surgery, will impact male fertility.
This marks a major improvement over semen analysis, the standard diagnostic tool for male infertility for ages. Its descriptive nature fails to explain the causes of infertility or predict whether sperm will actually fertilize an egg. However the Cap-Score, on the other hand, quantifies “capacitation,” the changes that take place within a sperm cell that enable it to fertilize.
The percentage of capacitated sperm determined by GM1 localization (Cap Score) differs between cohorts of fertile and potentially infertile men, and retrospectively, between men conceiving or failing to conceive by intrauterine insemination (IUI).
“Out of all the tests commonly used to measure sperm, the Cap-Score is the only one that prospectively has been shown to indicate the probability of a man to generate a pregnancy,” said Dr. Alexander Travis, professor of reproductive biology in the Department of Biomedical Sciences.
Travis was the first to identify ganglioside GM1 as a biomarker for a sperm’s capacitation status.
The investigators collected 208 semen samples from men having medical evaluations because of questions regarding their fertility. In addition to undergoing traditional semen analysis, the researchers tested the samples and assigned them prospectively into groups predicted to have low versus normal fertility based on their Cap-Scores. Clinical outcomes were later reported for 91 of these men.
Men with normal Cap-Scores had a 2.78-fold higher chance of pregnancy than men with a low score and a 4.23-fold higher success rate at achieving pregnancy in their first attempt at IUI. In contrast, none of the elements of semen analysis, such as sperm swimming or concentration, had any relationship with male fertility.
“This new ability to diagnose a man’s fertility status and ability to generate a pregnancy will let doctors counsel their patients toward a personalized journey to parenthood, using the approaches most appropriate for them,” Travis said. He hopes such targeted treatments will save couples time, emotional distress and money. This is especially important for patients who are attempting to get pregnant later in life when conception rates are reduced.
The ability to quantify the process that controls fertility within a sperm cell may have many implications such as help sperm banks improve how they handle and freeze sperm, give new public health insights into overall male health and well-being, and enable pharmaceutical companies to test off-target impacts of new drugs.