Elephants by the water


Elephants at risk of extinction and human couples facing infertility may not seem to have much in common, but now both may have a better chance of getting pregnant thanks to fertility researchers at Cornell 

Sperm Motility, Hope for Fertility

April 14, 2014

Elephants by the water


Elephants at risk of extinction and human couples facing infertility may not seem to have much in common, but now both may have a better chance of getting pregnant thanks to fertility researchers at Cornell. The Atkinson Center’s faculty director of environment Alex Travis (BAKERI) and his collaborators have advanced the understanding of how sperm function. Their findings point to new fertility treatments and techniques that may one day help endangered species in captive breeding programs and the roughly 10 percent of human couples with fertility problems.

Cornell researchers partnered with scientists from the Smithsonian Conservation Biology Institute to tackle a problem that complicates captive breeding of Asian elephants. Habitat loss and ivory poaching targeting male Asian elephants severely threaten the genetic diversity of the species. “Captive breeding is an important tool to preserve genetic diversity, but it’s extremely difficult with elephants,” Travis explained. “Ideally, instead of moving elephants, we’d move their genes through use of semen samples, like in cattle and dog breeding.”

The problem is that elephant semen samples are often not fertile enough to use in breeding. The same bull can produce samples with excellent sperm motility and less fertile samples in which almost none of the sperm are swimming. Working with Smithsonian scientists, Travis’s lab compared pairs of good and bad semen samples collected from 21 bulls. They found that the sperm were the same in each bull’s high- and low-motility samples, but the seminal plasma was different in the samples with swimming sperm. Seminal plasma fuels and protects sperm and is critical to sperm function and fertility. In elephants, it is made in accessory sex glands buried deep in the abdomen.

In addition to higher volumes of plasma, the more fertile samples had a specific protein in the seminal plasma that the low-motility samples did not contain. A key contribution of one of the accessory sex glands was missing in the samples with poor motility.

“This is an exciting discovery,” Travis explained, “because it tells us the problem isn’t the elephants: it’s the sperm collection methods.” The next step will be to develop new collection methods that reliably stimulate all the organs needed to make breeding-quality semen samples. Scientists may also be able to create media that mimic seminal plasma to preserve sperm function when bull elephants’ sex glands are not stimulated to produce all the necessary ingredients for motility.

Travis recently published a second high-profile study, with applications for humans, livestock, and endangered species. His research team has identified a component of the sperm membrane called GM1 that controls a critical step in fertilization. As a sperm approaches an egg, GM1 opens a specific calcium channel on the surface of the sperm head to admit a tiny amount of calcium. This movement of calcium must be completed before the sperm can release the enzymes that help it pass through the egg’s outer coating.

“Identifying these key steps that regulate whether a sperm can fertilize an egg opens up several potential applications, ranging from promoting fertility to developing contraceptives,” said Travis. “For example, if we could find a small molecule that mimicked this interaction, it might provide a new approach for a topical spermicide, replacing detergents that make certain users more susceptible to sexually transmitted diseases.” Future uses that could help both humans and endangered species include improved media for freezing sperm and a new test for male fertility using GM1 as a biomarker. The new fertility assay, which Travis’s team developed at Cornell, is already in human clinical trials at Weill Cornell Medical College.

As ACSF’s faculty director of environment, Travis is helping to implement the six priority research areas that emerged from the Center’s recent strategic planning process. Sustainability research in the One Health focus area emphasizes the links between ecosystem health and the health and well-being of all species. In May, Travis will lead a group of 19 ACSF Faculty Fellows to the Smithsonian Conservation Biology Institute facility in Front Royal, Virginia, to discuss broadening the partnership between Cornell and Smithsonian conservation scientists.

“Expanding our joint programs with the Smithsonian is a high priority for ACSF,” Travis remarked. “Partners such as the Smithsonian are addressing complex challenges around the world, as countries try to conserve their biodiversity while continuing to develop economically. Through the Atkinson Center, Cornell can bring its tremendous breadth and depth of expertise to bear on these problems. As partners, we can have a much greater impact than either organization would alone.”
 
Read more about Travis’s research on Asian elephants and GM1.




Elephants at risk of extinction and human couples facing infertility may not seem to have much in common, but now both may have a better chance of getting pregnant thanks to fertility researchers at Cornell