【“试管中的眼球”可以揭示我们如何看到颜色和治疗某些形式的失明】

【“试管中的眼球”可以揭示我们如何看到颜色和治疗某些形式的失明】研究人员利用干细胞从零开始培养人类视网膜,这一实验揭示了我们如何看到颜色。约翰斯·霍普金斯大学的生物学家想要确定可以让人看到颜色的细胞是如何形成的。研究小组将重点放在让人们看到蓝色、红色和绿色的细胞上,这是人眼中的三种锥状光感受器。约翰·霍普金斯大学研究生基拉·埃尔德雷德(Kiara El谋德)说,三色视觉将我们与大多数其他哺乳动物区分开来。这项发表在“科学”杂志上的研究,可能会为诸如色盲和黄斑变性等眼病带来全新的治疗方法。

'Eye-ball in a test-tube' could reveal the secret of how we see in color and cure some forms of blindness

Researchers have grown human retinas from scratch using stem cells in a radical experiment that reveals how we see in color.

The biologists at Johns Hopkins University wanted to determine how cells that allow people to see in color are made.

The study, in the journal Science, could lead to radical new therapies for eye diseases such as color blindness and macular degeneration.

The researchers say their groundbreaking study could lead to new ways to study the human body.

'Everything we examine looks like a normal developing eye, just growing in a dish,' said Robert Johnston, a developmental biologist at Johns Hopkins.

'You have a model system that you can manipulate without studying humans directly.'

Most vision research is done on mice and fish, but neither has the dynamic daytime and color vision of humans.

So Johnston's team created the human eye tissue they needed - with stem cells.

The team focused on the cells that allow people to see blue, red and green—the three cone photoreceptors in the human eye.

'Trichromatic color vision differentiates us from most other mammals,' said lead author Kiara Eldred, a Johns Hopkins graduate student.

'Our research is really trying to figure out what pathways these cells take to give us that special color vision.'

Over months, as the cells grew in the lab and became full-blown retina tissue, the team found the blue-detecting cells materialized first, followed by the red- and green-detecting ones.

In both cases, they found the key was the ebb and flow of thyroid hormone.

The level of this hormone wasn't controlled by the thyroid gland, which of course isn't in the dish, but entirely by the eye itself.

Understanding how the amount of thyroid hormone dictated whether the cells became blue or red and green receptors, the team was able to manipulate the outcome, creating retinas that if they were part of a complete human eye would only see blue, and ones that could only detect green and red.

This is a huge insight into why pre-term babies, who have lowered thyroid hormone levels as they are lacking the maternal supply, have a higher incidence of vision disorders.

'If we can answer what leads a cell to its terminal fate, we are closer to being able to restore color vision for people who have damaged photoreceptors,' Eldred said.

'This is a really beautiful question, both visually and intellectually—what is it that allows us to see color?'

These findings are a first step for the lab.

In the future, the researchers would like to use organoids to learn even more about color vision and the mechanisms involved in the creation of other regions of the retina, such as the macula.

Since macular degeneration is one of the leading causes of blindness in people, understanding how to grow a new macula could lead to clinical treatments.

'What's exciting about this is our work establishes human organoids as a model system to study mechanisms of human development,' Johnston said.

'What's really pushing the limit here is that these organoids take nine months to develop just like a human baby.

'So what we're really studying is fetal development.'

原文链接:https://www.dailymail.co.uk/sciencetech/article-6270617/The-lab-grown-retina-reveals-secret-color.html


Comments are closed.



无觅相关文章插件