Development of new technologies of assisted reproduction
Development of new technologies of assisted reproduction: male fertility diagnostics in human and non-human animals, and in vitro fertilization, embryo transfer and stem cell technologies in dogs
Applications for our work in the cell biology of reproduction extend into technologies of assisted reproduction as well as cryopreservation and diagnosis of male fertility. For example, our work on GM1 has formed the basis of an assay of sperm function that diagnoses male fertility. This assay is currently being tested in a clinical trial at the Weill-Cornell Medical College by Dr. Gianpiero Palermo.
Development of new technologies of assisted reproduction are an important component of our work in wildlife and domestic animals that can serve as models for wild species. Although dogs are the most commonly seen animals in veterinary practices, very little is known about reproduction in dogs because they differ so much from other mammals. Their eggs are ovulated at a much earlier stage of development; they only cycle once or twice a year; and their hormone profiles are almost identical whether pregnant or not-pregnant. All these differences have resulted in almost no advancements in assisted reproduction. We don’t know how they come out of anestrus, so there are no optimized protocols to induce or synchronize estrus. We don’t know how to mature their eggs in the lab, so no puppies have ever been produced by in vitro fertilization. Lastly, the high lipid content of dog eggs has made freezing eggs or embryos very difficult.
Working in collaboration with the Smithsonian Conservation Biology Institute, we are trying to overcome these challenges by studying in vitro fertilization in the dog, maturing canine ooctyes, and cryopreserving canine embryos. Our early results have been quite promising—we recently announced the birth of Klondike, the first puppy in the Western hemisphere, born from a frozen embryo. Work on assisted reproduction in dogs has impacts beyond the veterinary care of pets and working dogs, in that it also provides a foundation for studies of the reproduction of wild canids, such as African wild dogs or maned wolves.
We are also performing research and developing technologies based on spermatogonial stem cells. These cells are present from birth in the testes, whereas sperm are only produced after puberty. Therefore, if we can save an individual’s spermatogonia and transplant them into a recipient, we could then have that recipient produce the donor’s sperm. This technique is known as spermatogonial stem cell transplantation and we were the first to carry it out successfully in dogs. This method could theoretically provide a way to save an animal’s reproductive potential even if it dies before producing sperm and reproducing. Unfortunately, the death of neonatal or juvenile animals can be an important problem when populations of endangered species reach low numbers. We are also working on a complementary approach known as testis xenografting.
For more information on our work on wildlife, please see our pages on the Cornell Center for Wildlife Conservation website.