Washington State University researchers have found a promising way to protect sperm stem cells so boys could undergo malignancy treatment without risking their fertility.
Adult men can have their sperm frozen before going through radiation or chemotherapy, both of which can render semen infertile. But boys who haven’t been through puberty can simply have sperm stem cells removed and frozen within anticipation of technology that could culture the cells and place all of them back in the testes, where they produce sperm after puberty.
Jon Oatley, an associate professor in the WSU School of Molecular Biosciences and director of the Middle for Reproductive Biology, said he and his colleagues are very well on their way to developing such a technology.
“I think it’s going to become the standard by which everybody cultures their own cells, including trying to develop conditions for human tissues, ” said Oatley. He and his colleagues — graduate student Aileen Helsel and lab manager Melissa Oatley — report on the new technique in the journal Stem Cell Reports .
Stem cell can produce 5, 000 sperm
Fewer than 1 percent of the nation’s cancer cases include children, according to the American Cancer Society, which estimated that the little more than 10, 000 children under the age of fifteen would be diagnosed with cancer last year. Better than four out of 5 survive five years or more, but prepubescent boys danger getting azoospermia, a lack of viable sperm.
“After the cancer is controlled, the quality of life, which often consists of the ability to have a normal child, becomes a major issue, ” stated Marvin Meistrich, an University of Texas oncologist, creating in the journal Pediatric Blood & Cancer.
With each heartbeat, mature, fertile men produce a few 1, 300 sperm cells. They come from a pool associated with self-renewing spermatogonial stem cells that are present at delivery. As each stem cell differentiates, it can produce several 5, 000 sperm.
Eight-fold enhancement in viable sperm stem cells
Working with prepubescent mouse pups, Oatley and his colleagues place a fluorescent tag on a gene specific to come cells. This let them in effect watch the process of an originate cell differentiating to create the progenitors that eventually turn out to be sperm.
Early in the process, they saw the particular stem cells creating energy through one method, called glycolysis, then switching to another method. The second method, called oxidative phosphorylation, produces free radicals, reactive forms of oxygen which can be particularly harmful to a cell’s DNA.
“If you’re a stem cell that is going to give rise to sperm basically through the whole lifetime of an individual, you want to have a pristine genome, ” said Oatley. “You don’t want it damaged simply by reactive oxygen species. That’s why we think glycolysis is important for your stem cell. So we tried to change the culture environment in order to favor glycolysis. ”
By lowering the particular oxygen in the culture — adding nitrogen to cut this by more than half — the researchers found they could significantly improve the percentage of stem cells capable of making regular sperm when put back into the testes. Where before just 5 percent of the cells remained viable after six months, today 40 percent were viable.
“We’re obtaining an eight-fold improvement, ” Oatley said.
Next steps: Epigenetic, human tissue studies
The WSU researchers still have a host of problems to confront. Working with Marisa Bartolomei at the University associated with Pennsylvania, they plan to see if the cultured stem cellular material undergo changes to their epigenome, which determines if genetics are turned on and off. The team also will check out whether the technique will work with human tissues.
Materials provided by Washington Condition University . Original written by Eric Sorensen. Note: Content may be edited for style and size.