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我们已经准备好对新生儿进行基因编辑了吗? – 译学馆
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我们已经准备好对新生儿进行基因编辑了吗?

Are We Ready to Edit the Fetal Genome?

本节目(SciShow)由
This episode of SciShow is brought to you
美国基因和细胞治疗学会支持播出
by the American Society of Gene and Cell Therapy.
【片头】
[♪ INTRO]
在最近的几十年里
Gene therapy is probably one of the most mind-boggling developments
基因治疗可以说是一种最令人震惊的发展
in the last few decades of medicine
通过改变患者基因组成
The fact that we can treat certain diseases
而达到治疗某一疾病的效果
by changing someone’s genetic makeup
听起来像是摘自科幻小说
seems like it should be straight out of a sci-fi book
其实 在我小时候情况确实是这样
In fact, when I was a kid, it was
但人们对此有些误解
But it can also be a little misunderstood
最常见的一种误解是
One of the most common misconceptions about gene therapy
未来某天基因治疗会用于“设计试管婴儿”
is the idea that it will someday be used to create what people call “designer babies”
即出生前选择婴儿特征
essentially kids who have their traits chosen before birth
比如智力、眼睛颜色
Things like intelligence or eye color
或者将来是否会秃头
or even whether or not they’re gonna go bald later in life
目前大多数基因治疗研究
The truth is most gene therapy research right now
并不包括修饰胎儿细胞
doesn’t involve modifying fetal cells at all
即使涉及修饰胎儿细胞
And even when it does
研究人员也会寻找预治基因疾病的方法
researchers are looking to prevent or treat genetic disorders
而不是去设计修饰DNA
not customize DNA just because they can
在某些方面 基因治疗和其他药物相似
In some ways, it’s just like every other kind of medicine
而从其他方面来看 二者又十分不同
And in others, it is very, very different
不管怎样
But one way or another
产前基因编辑将是未来医学的主要部分
fetal gene editing could be a big part of the future of medicine
未来医学发展之快将超乎想象
— a future that may be here faster than you think
基因治疗有几种类型
There are a few different types of gene therapy
但研究最充分的是病毒疗法
but the best-studied ones involve viruses
简单来说 研究人员选择一种病毒作为载体
The basic idea is that scientists take a virus, called a vector
移除该病毒的致病成分
and remove the part that cause disease
然后注入遗传信息供该载体表达
and then they insert bundles of information for the vector to deliver instead
这种信息通常是指令
That information usually takes the form of instructions
比如生产一种自然状态下自身无法合成的蛋白质
telling the body to produce something like a protein that it’s naturally lacking
例如 血友病患者缺乏足够的特定凝血蛋白
For example, those with hemophilia don’t have enough of a specific blood-clotting protein
所以用于治疗血友病的基因含有合成凝血蛋白分子的信息
So the gene to treat it would tell their cells to start making those protein molecules
过去几年内
Over the last few years
基因治疗试验的成功案例越来越多
there have been an increasing number of successful gene therapy tests
不论是用于实验室动物还是人类
in both lab animals and humans
不过 出生后治疗某种疾病可能会导致并发症
But treating a disease after someone is born can still come with some complications
某些疗法有风险
Some treatments come with risks
另一些疗法则不够详尽
others aren’t thorough enough
而在某些情况下完全找不到有效疗法
and for some conditions, there just aren’t useful treatments at all
所以胎儿基因治疗的理念是
So the idea behind fetal gene therapy
在出生前预防疾病
is to prevent these diseases before someone is born
可以是直接从胚胎开始治疗
It might involve treating an embryo directly
或是将载体注入羊水中来之治疗胎儿
or treating a fetus by injecting vectors into something like the amniotic fluid
但不论疗法如何 大多数研究者一致认为
But whatever the method, most researchers agree that
不是所有情况都适用于基因治疗
these treatments shouldn’t be used for just anything
上世纪九十年代末
In the late 1990s
英国基因治疗咨询委员会发布了两项标准
the UK’s Gene Therapy Advisory Committee published two criteria
要求任何有考虑价值的产前治疗都应达到标准
that any fetal treatments worth considering should meet
首先 产前治疗相比于其他疗法有明显优势
First, they should have a clear advantage over other treatments
例如器官移植和产后治疗
like transplants or postnatal therapy
第二 产前治疗应当用于没有最适疗法的致命疾病
And secondly, they should be used for life-threatening diseases with no suitable treatment
换言之 其核心理念是
In other words, the heart behind this
帮助人尽可能恢复健康
is to help people to be as healthy as possible
就好比其他药物一样 而不是说
just like other types of medicine — not to, say
通过基因工程设计出X-战警
genetically engineer an X-Man
其他伦理委员会的意见与此一致
The general consensus of other ethics committees has been along the same lines
即使制定了行为准则
still even with guidelines in place
目前大多数基因疗法风险系数太高 不可用于人类胎儿
most of these therapies are currently too risky to try in human fetuses
所以相关研究只限于动物模型
so research has mostly been confined to animal models
化验孕妇的血液和组织就可得知
Pregnant people can get blood and tissue tests to determine
其胎儿是否可能患有遗传疾病
if their child is likely to have a genetic disease
例如囊性纤维化、血友病以及镰刀型细胞贫血
including cystic fibrosis, hemophilia, and sickle cell anemia
不过就算检验结果呈阳性 眼下也没有许多办法可供选择
But there are not many immediate options if those tests are positive
不过我们正慢慢取得进展
We are making progress, though
2018年《自然医学》发布了一项具有广阔前景的研究
In 2018, a promising study in Nature Medicine
研究表明 产前基因治疗可以医治小鼠的某种疾病
showed how fetal gene therapy could treat an illness in mice
这种疾病与人类的脑苷脂沉积病类似
that is similar to Gaucher’s disease in humans
脑苷脂沉积病是一种遗传病 会致使某种酶失活
Gaucher’s is an inherited disorder that causes an enzyme deficiency
具体来说是葡糖脑苷脂酶
specifically for an enzyme called glucocerebrosidase
若没有正常水平的葡糖脑苷脂酶 废物就会在体内堆积
Without healthy levels of it, waste builds up in the body
导致各种各样的疾病
which can lead to all kinds of trouble
一般来说 通过每周注射相应酶可以治疗这种疾病
Often, this disease can be treated by getting weekly enzyme injections
但是Ⅱ型脑苷脂沉积病没有治疗方法
but a certain type of Gaucher’s, type 2, isn’t treatable
患Ⅱ型的人大脑中没有足够的葡糖脑苷脂酶
In this type, there isn’t enough glucocerebrosidase in the brain
由于血脑屏障可以屏蔽掉大多数分子
And because of the blood-brain barrier that filters out most molecules
所以注射酶类并不起作用
the enzyme injections don’t work
这种疾病通常是致命的
The disease is often fatal
婴儿出生的那刻已经累积了大量损伤
and by the time a baby is born,a lot of the damage has already been done
因此研究人员力图通过产前基因治疗来医治此病
So researchers have been looking into how to treat it using fetal gene therapy
在2018年的一项实验中
In the 2018 experiment
研究者向胎鼠脑中注射装载了指令的载体
scientists injected the brains of fetal mice with vectors full of instructions
用以表达缺失的葡糖脑苷脂酶
to make that missing enzyme
似乎奏效了
and it seemed to help
小鼠的酶活性相对正常
The mice had relatively normal enzyme activity
虽然它们往往体重减轻 而且在运动试验中表现也不佳
although they did tend to weigh less and didn’t perform as well on movement tests
一项后续实验似乎更加鼓舞人心
A follow-up experiment seemed to be even more encouraging
研究人员将载体注入血液而非大脑中
In it, researchers injected the vectors into the bloodstream instead of the brain
出于伦理原因 这些小鼠只允许存活55天
The mice were only allowed to be kept alive for 55 days for ethical reasons
但在此期间也无法看出它们与正常小鼠的区别
But during that time, they didn’t seem to be any different from regular mice
该团队的研究结果也表明
The team also showed that
这种载体注射方法也可用于大型动物胚胎 例如猕猴
this vector-injecting method worked on larger animal fetuses like macaques
这项研究如此成功 一些科学研究者不禁认为
The study was so successful that some scientists argue
是时候将此方法用于人类临床试验中了
we are ready to start clinical trials of this method in humans
但有人提出反对 他们认为临床前研究取得成功
But others disagree, pointing out that success in pre-clinical studies
并不意味着临床试验也会成功
doesn’t always equal success in clinical trials
他们认为还有待进一步研究
So they think we need to keep researching
因为产前基因治疗的相关事宜
Because that’s the thing about fetal gene therapy
从科学和伦理上来说都相当复杂
It’s really complicated, both scientifically and ethically
毕竟 一旦开始临床试验
After all, as soon as you start clinical trials
就涉及到将会发育为成熟个体的人类胚胎或胎儿
treating human embryos or fetuses that will develop into full-grown kids
你在拿一个人的生命做实验
you’re dealing with a person’s life
这不可当儿戏对待
And that’s not something to be taken lightly
以前我们也进行过胎儿试验
We have done trials on fetuses before
但使用的都是经过充分研究、效果安全的方法
but only using methods that were heavily studied and shown to be safe
2018年《新英格兰医学杂志》发布了另一项研究
Like in another 2018 study published in The New England Journal of Medicine
研究人员应用产前基因治疗来预防XLHED
researchers used fetal gene therapy to prevent XLHED
一种导致汗腺受损的遗传病—— 在三例婴儿中
an inherited disorder that impairs sweat glands — in three babies
论文发表时婴儿已经一岁半了
The kids were around a year and a half old when the paper was published
看上去也很健康
and seemed to be doing okay
关键在于 研究者使用的是经广泛试验的方法
The key was that the researchers were using extensively tested methods
而且获得了所在医院伦理委员会的许可
and also got permission from their hospital’s ethics committee
几个月前的爆炸性新闻与此截然不同
That’s very different from the news that broke just a few months later
中国一位研究者利用CRISPR修饰了人类胚胎
When it came out that a Chinese researcher had altered human embryos using CRISPR
CRISPR是一种新型基因编辑技术
a newer gene-editing technique
这项试验违反了大多数公认的伦理准则
This trial violated most of the accepted ethical guidelines
从一方面看 其目的是降低婴儿感染艾滋病的几率
For one, it was done to reduce the babies’ chances of contracting HIV
不过达成此目的还有其他风险更低的方法
and there are much less risky ways to do that
这位研究者也没有获得伦理委员会的许可
The scientist also didn’t get permission from a committee
而且最重要的是 他使用的方法并不安全
most importantly, the method he used isn’t established as safe
基因编辑技术在实验室内大量应用
CRISPR has done great in the lab
但它也会导致偶发突变
but it’s also been shown to cause occasional accidental mutations
幸运的是 目前孩子很健康
Thankfully, the kids are healthy so far
但这并不意味着会一直健康
but that doesn’t mean they always will be
所以说 制定伦理准则是有原因的
So let’s just say there’s a reason we have these guidelines
未来我们将会进入这样一个时期
In the future, there will likely be a time
用不同方法安全地编辑胚胎基因组
when we can safely edit an embryo’s genome in all kinds of different ways
但即使这一天真的到来
But even when that day comes
我们也需考虑其他事情
there will be other things to think about too
比如某人经修饰的基因传递给了后代
Like what would be the consequences
类似这样的后果
if someone’s edited genes were passed to their offspring?
或者是经修饰的基因在生命历程中又发生了突变
or if the edited gene mutated over the course of someone’s life?
还有更糟糕的问题
And then there are even messier questions
比如基因编辑的界限何在
like how far is too far when it comes to gene editing
科学是否在干预进化
and if this science is interfering with evolution
或者说科学是否对于进化影响重大
or if it matters if it is
目前我们只能说
The most we can say is that, right now
产前基因编辑只适用于必要治疗
fetal gene therapy is really only intended for necessary treatments
下一步是继续已经开始的动物试验
The next steps are to continue the animal tests scientists have already started
来充分探知其科学原理和风险所在
to really understand how this science works and what the risks are
因为最终
Because at the end of the day
当这些实验将被准许频繁用于人类临床试验时
when these experiments are approved for more frequent clinical trials in humans
我们希望确保这些实验足够安全
we want to make sure they are as safe as possible
如果你乐于关注最新研究进展
If you’re interested in keeping up with the latest research
可以看看美国基因和细胞治疗协会旗下的新型患者教育网站
you should check out the new patient education portal from the American Society of Gene and Cell Therapy
你所想了解的一切 在这里应有尽有
It’s a super comprehensive resource for everything you’ve ever wanted to know about
比如基因治疗不同类型及其原理
the different types of gene therapy, how they work,
目前为止对各种不同治疗手段的研究
and both past and ongoing research into all kinds of treatments
而且 它还是完全免费的
And it is completely free
如果你想好好看看
To check it out for yourself
只需登陆asgct.org/education
just head over to asgct.org/education
或者点击下方的链接
or follow the link in the description below

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视频概述

通过改变胎儿的基因组成来达到治疗目的

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视频来源

https://www.youtube.com/watch?v=fxjZqvu1rko

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