Researchers: Progress Made in Creating Pre-embryo Models

Scientists have reported new progress in creating pre-embryo¹ models from stem cells in a laboratory.

Stem cells are simple cells in the body that can develop into one of many specialized² cells.

Researchers say the models can provide an effective and ethical³ way to study human development and to seek new discoveries in reproductive technology.

The latest efforts are described in a study that recently appeared in the publication Nature.

The lab-created pre-embryo structures are called "blastoids." They act as a model for blastocysts, collections of cells that form during the early period of human embryonic⁴ development. Blastocysts form a few days after an egg has been fertilized⁵, but before it attaches to the uterus to become an embryo.

Scientists have successfully used human cell material to create pre-embryos⁶.

Nicolas Rivron is a researcher at the Austrian Academy of Sciences who helped lead the study. He said the models are a very good research alternative to human embryos. This is partly because donated embryos are hard to get and can be difficult to work with in a lab.

Rivron said it is "extremely difficult" to use human embryos to make molecule⁷ and gene⁸ discoveries in a lab. He added that this limits the ability of scientists "to better understand development and also make biomedical discoveries."

But Rivron said lab-created versions can be made, changed and studied in large numbers to expand human embryonic research. This opens the possibility for new scientific and biomedical discoveries, he added.

For example, Rivron said studying blastoids could lead to the development of birth control treatments that do not contain hormones¹⁰.

To create the blastoids, Rivron said his team used two different kinds of stem cells: embryonic stem cells from already established cell lines and stem cells reprogrammed from adult cells. No new embryonic cell lines were made for the research.

Rivron said blastocysts were grown separately to compare them side-by-side with the lab-created structures.

The study showed that the blastoids effectively reproduced important parts of early embryo development. Some were placed in contact with cells from the lining¹¹ of a uterus that had been given hormones. About half of the blastoids attached to the cells and started to grow in the same way as blastocysts would.

Rivron said the researchers stopped the blastoid growth after 13 days and examined the cells. At that point, he said the collection of cells did not show the level of growth or organization that would be expected after 13 days in an embryo.

Rivron said ethical concerns were also considered. A "14-day rule" has long guided researchers growing embryos in the lab. Earlier this year, the International Society for Stem Cell Research urged changes to the rule in limited cases.

Rivron said blastoids are not subject to that rule. But he noted¹² the guidelines state that they should never be placed into an animal or human.

"It is very clear that blastoids are not embryos...and if they are not, then why would we apply the 14-days rule to these structures?" he said. But Rivron added that his team decided¹³ to stop after 13 days "for the sake of transparency and for making sure things are very well understood by the public."

Magdalena Zernicka-Goetz is an expert in stem cell biology at the University of Cambridge in Britain. She was not involved in the study. Zernicka-Goetz noted that it is not the first time scientists have created a human blastoid. But she noted that "every single step is significant," in helping¹⁴ researchers improve the process and create better models.

Words in This Story

ethical – adj. relating to what is right or wrong

alternative – n. one of two or more things that you can choose between

hormone⁹ – n. a natural substance that is produced in the human body and determines how the body grows and develops

transparent¹⁵ – adj. honest and open; not secretive

significant – adj. important or noticeable

1 embryo   

n.胚胎，萌芽的事物

参考例句：

• They are engaging in an embryo research.他们正在进行一项胚胎研究。
• The project was barely in embryo.该计划只是个雏形。

2 specialized   

adj.专门的，专业化的

参考例句：

• There are many specialized agencies in the United Nations.联合国有许多专门机构。
• These tools are very specialized.这些是专用工具。

3 ethical   

adj.伦理的，道德的，合乎道德的

参考例句：

• It is necessary to get the youth to have a high ethical concept.必须使青年具有高度的道德观念。
• It was a debate which aroused fervent ethical arguments.那是一场引发强烈的伦理道德争论的辩论。

4 embryonic   

adj.胚胎的

参考例句：

• It is still in an embryonic stage.它还处于萌芽阶段。
• The plan,as yet,only exists in embryonic form.这个计划迄今为止还只是在酝酿之中。

5 Fertilized   

v.施肥( fertilize的过去式和过去分词 )

参考例句：

• The study of psychology has recently been widely cross-fertilized by new discoveries in genetics. 心理学研究最近从遗传学的新发现中受益匪浅。
• Flowers are often fertilized by bees as they gather nectar. 花常在蜜蜂采蜜时受粉。

6 embryos   

n.晶胚；胚，胚胎( embryo的名词复数 )

参考例句：

• Somatic cells of angiosperms enter a regenerative phase and behave like embryos. 被子植物体细胞进入一个生殖阶段，而且其行为象胚。 来自辞典例句
• Evolution can explain why human embryos look like gilled fishes. 进化论能够解释为什么人类的胚胎看起来象除去了内脏的鱼一样。 来自辞典例句

7 molecule   

n.分子，克分子

参考例句：

• A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈̬f婘̬ 妈̬成的。
• This gives us the structural formula of the molecule.这种方式给出了分子的结构式。

8 gene   

n.遗传因子，基因

参考例句：

• A single gene may have many effects.单一基因可能具有很多种效应。
• The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。

9 hormone   

n.荷尔蒙，激素，内分泌

参考例句：

• Hormone implants are used as growth boosters.激素植入物被用作生长辅助剂。
• This hormone interacts closely with other hormones in the body.这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。

10 hormones   

n. 荷尔蒙，激素 名词hormone的复数形式

参考例句：

• This hormone interacts closely with other hormones in the body. 这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。
• The adrenals produce a large per cent of a man's sex hormones. 肾上腺分泌人体的大部分性激素。

11 lining   

n.衬里，衬料

参考例句：

• The lining of my coat is torn.我的外套衬里破了。
• Moss makes an attractive lining to wire baskets.用苔藓垫在铁丝篮里很漂亮。

12 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

13 decided   

adj.决定了的，坚决的；明显的，明确的

参考例句：

• This gave them a decided advantage over their opponents.这使他们比对手具有明显的优势。
• There is a decided difference between British and Chinese way of greeting.英国人和中国人打招呼的方式有很明显的区别。

14 helping   

n.食物的一份&adj.帮助人的，辅助的

参考例句：

• The poor children regularly pony up for a second helping of my hamburger. 那些可怜的孩子们总是要求我把我的汉堡包再给他们一份。
• By doing this, they may at times be helping to restore competition. 这样一来, 他在某些时候,有助于竞争的加强。

15 transparent   

adj.明显的，无疑的；透明的

参考例句：

• The water is so transparent that we can see the fishes swimming.水清澈透明，可以看到鱼儿游来游去。
• The window glass is transparent.窗玻璃是透明的。