University of Edinburgh

Building a new mouse, one stem cell at a time

/ Kevin McCormack / Leave a comment

Science is full of acronyms. There are days where it feels like you need a decoder ring just to understand a simple sentence. A recent study found that between 1950 and 2019 researchers used more than 1.1 million unique acronyms in scientific papers. There’s even an acronym for three letter acronyms. It’s TLAs. Which of course has one more letter than the thing it stands for.

I only mention this because I just learned a new acronym, but this one could help change the way we are able to study causes of infertility. The acronym is IVG or in vitro gametogenesis and it could enable scientists to create both sperm and egg, from stem cells, and grow them in the lab. And now scientists in Japan have done just that and allowed these fertilized eggs to then develop into mice.

The study, published in the journal Science, was led by Dr. Katsuhiko Hayashi of Kyushu University in Japan. Dr. Hayashi is something of a pioneer in the field of IVG. In the past his team were the first to produce both mouse sperm, and mouse eggs from stem cells. But they ran into a big obstacle when they tried to get the eggs to develop to a point where they were ready to be fertilized.

Over the last five years they have worked to find a way around this obstacle and, using mouse embryonic stem cells, they developed a process to help these stem cell-generated eggs mature to the point where they were viable.

In an article in STAT News Richard Anderson, Chair of Clinical Reproductive Science at the University of Edinburgh, said this was a huge achievement: “It’s a very serious piece of work. This group has done a lot of impressive things leading up to this, but this latest paper really completes the in vitro gametogenesis story by doing it in a completely stem-cell-derived way.”

The technique could prove invaluable in helping study infertility in people and, theoretically, could one day lead to women struggling with infertility to be able to use their own stem cells to create eggs or men their own sperm. However, the researchers say that even if that does become possible it’s likely a decade or more away.

While the study is encouraging on a scientific level, it’s raising some concerns on an ethical level. Should there be limits on how many of these manufactured embryos that a couple can create? Can someone create dozens or hundreds of these embryos and then sift through them, using genetic screening tools, to find the ones that have the most desirable traits?

One thing is clear, while the science is evolving, bioethicists, scholars and the public need to be discussing the implications for this work, and what kinds of restraints, if any, need to be applied before it’s RFPT (ready for prime time – OK, I made that one up.)

Stem cell study shows how smoking attacks the developing liver in unborn babies

/ Kevin McCormack / Leave a comment

smoking mom

It’s no secret that smoking kills. According to the Centers for Disease Control and Prevention (CDC) smoking is responsible for around 480,000 deaths a year in the US, including more than 41,000 due to second hand smoke. Now a new study says that damage can begin in utero long before the child is born.

Previous studies had suggested that smoking could pose a serious risk to a fetus but those studies were done in petri dishes in the lab or using animals so the results were difficult to extrapolate to humans.

Researchers at the University of Edinburgh in Scotland got around that problem by using embryonic stem cells to explore how the chemicals in tobacco can affect the developing fetus. They used the embryonic stem cells to develop fetal liver tissue cells and then exposed those cells to a cocktail of chemicals known to be found in the developing fetus of mothers who smoke.

Dangerous cocktail

They found that this chemical cocktail proved far more potent, and damaged the liver far more, than individual chemicals. They also found it damaged the liver of males and females in different ways.  In males the chemicals caused scarring, in females it was more likely to negatively affect cell metabolism.

There are some 7,000 chemicals found in cigarette smoke including tar, carbon monoxide, hydrogen cyanide, ammonia, and radioactive compounds. Many of these are known to be harmful by themselves. This study highlights the even greater impact they have when combined.

Long term damage

The consequences of exposing a developing fetus to this toxic cocktail can be profound, including impaired growth, premature birth, hormonal imbalances, increased predisposition to metabolic syndrome, liver disease and even death.

The study is published in the Archives of Toxicology.

In a news release Dr. David Hay, one of the lead authors, said this result highlights yet again the dangers posed to the fetus by women smoking while pregnant or being exposed to secondhand smoke :

“Cigarette smoke is known to have damaging effects on the foetus, yet we lack appropriate tools to study this in a very detailed way. This new approach means that we now have sources of renewable tissue that will enable us to understand the cellular effect of cigarettes on the unborn foetus.”