In a bid to understand what causes infertility, or more specifically the failure of a sperm to fertilise an egg in the early stages, scientists have turned to human stem cells for the answer. Now, after a number of trials carried out by the University of Michigan, there could finally be an answer.
Cell biologists and engineers at U-M have been using lab-grown stems cells rather than embryos in the research, and have examined how they behave. The research, published in the journal Nature Communications, shows that the pluripotent human stem cells arranged themselves into a structure that resembles the early stages of human development. The behaviour of the cells was similar to those seen in a human’s amniotic sac.
“As many as half of all pregnancies end in the first two weeks after fertilization, often before the woman is even aware she is pregnant,” says co-senior author Deborah Gumucio, Ph.D, Engel Collegiate Professor of Cell & Developmental Biology at Michigan Medicine. “For some couples, there is a chronic inability to get past these critical early developmental steps, but we have not previously had a model that would allow us to explore the reasons why. We hope this work will make it possible for many scientists to dig deeper into the pathways involved in normal and abnormal development, so we can understand some of the most fascinating biology on earth.”
A WORLD FIRST
The research is particularly impressive, as it is the first time a team has grown a structure using stem cells as opposed to an embryo. The structure has been called a PASE, or post-implantation amniotic sac embryoid. The PASE is a hollow, spherical structure that has two distinct halves, one of which contains cells that will become the amniotic ectoderm while the other consist of what will make up the embryonic disc. The PASE structure communicates via a signaling pathway known as BMP-SMAD, and it is this pathway that is known to be crucial to the development of an embryo. The team is now hoping to learn more about PASE biology in a bid to uncover more about causes of infertility, and in the process, possible means of treatment.