(单词翻译:单击)
This episode of SciShow is brought to you by the American Society of Gene and Cell Therapy.
本期《科学秀》由美国基因与细胞治疗学会为大家呈现。
Gene therapy is probably one of the most mind-boggling developments in the last few decades of medicine.
基因治疗可能是医学界近几十年来最令人难以置信的发展之一。
The fact that we can treat certain diseases by changing someone's genetic makeup seems like it should be straight out of a sci-fi book.
事实上我们可以通过更改某人基因组成来治疗某些疾病，这听起来像是科幻小说。
In fact, when I was a kid, it was. But it can also be a little misunderstood.
其实，在我小时候这确实科幻小说。但其中也有些误解。
One of the most common misconceptions about gene therapy is the idea
关于基因治疗最常见的误解之一是认为
that it will someday be used to create what people call "designer babies", essentially, kids who have their traits chosen before birth.
某天它将被用于创造人们所说的“设计婴儿”，本质上来讲，就是那些在出生前经过挑选的孩子。
Things like intelligence or eye color, or even whether or not they're gonna go bald later in life.
比如选择智商或眼睛颜色，甚至是它们未来是否会秃头都可经过筛选。
The truth is, most gene therapy research right now doesn't involve modifying fetal cells at all.
事实上，现在大部分的基因治疗研究根本就不涉及修改胚胎细胞。
And even when it does, researchers are looking to prevent or treat genetic disorders —not customize DNA just because they can.
即便研究人员这么做了，他们也是希望可以预防或治疗基因疾病—而并不是有能力就为所欲为的定制DNA。
In some ways, it's just like every other kind of medicine. And in others… it is very, very different.
在某些方面，这就像是一种药。在其他方面....就非常非常不同了。
But one way or another, fetal gene editing could be a big part of the future of medicine
但不管怎样，胚胎基因编辑可能成为未来医学的重要部分
— a future that may be here faster than you think.
—这个未来可能比你想象的来的更快。
There are a few different types of gene therapy, but the best-studied ones involve viruses.
已经有几种不同的基因治疗类型，但被研究最充分的治疗涉及病毒。
The basic idea is that scientists take a virus called a vector and remove the parts that cause disease.
基本想法是科学家们采用一种被称为载体的病毒并将其中会导致疾病的部分移除。
Then, they insert bundles of information for the vector to deliver instead.
然后他们将大量信息植入载体，让载体将这些信息传送出去。
That information usually takes the form of instructions, telling the body to produce something like a protein that it's naturally lacking.
这些信息通常采用指令的形式告诉身体产生天生缺乏的物质，如一种蛋白质。
For example, those with hemophilia don't have enough of a specific blood-clotting protein.
例如，那些血友病患者体内缺乏某种凝血蛋白。
So the gene to treat it would tell their cells to start making those protein molecules.
所以治疗此的基因会告诉它们的细胞开始制造那些蛋白分子。
Over the last few years, there have been an increasing number of successful gene therapy tests in both lab animals and humans.
在过去的几年里，在实验室动物和人类身上取得基因治疗成功的例子不断增加。
But treating a disease after someone is born can still come with some complications.
但是在出生后再进行疾病治疗仍会出现一些并发症。
Some treatments come with risks, others aren't thorough enough, and, for some conditions, there just aren't useful treatments at all.
一些治疗还存在风险，其他治疗还不够彻底，有些疾病根本没有有效的治疗方法。
So the idea behind fetal gene therapy is to prevent these diseases before someone is born.
所以胚胎基因治疗的想法就是在出生前预防这些疾病。
It might involve treating an embryo directly, or treating a fetus by injecting vectors into something like the amniotic fluid.
其中可能会涉及对胚胎进行直接治疗或是通过将载体注射进羊水的方式治疗胚胎。
But whatever the method, most researchers agree that these treatments shouldn't be used for just anything.
但是不管哪种方法，大部分研究人员都同意不是任何问题都可使用这些治疗方法。
In the late 1990s, the UK's Gene Therapy Advisory Committee published two criteria that any fetal treatments worth considering should meet.
上世纪90年代末期，英国基因治疗咨询委员会发布两个标准，任何胚胎治疗都必须满足这两个标准。
First, they should have a clear advantage over other treatments, like transplants or postnatal therapy.
首先，它们应该有优于其他治疗方法（比如移植或产后治疗）的明显优势。
And secondly, they should be used for life-threatening diseases with no suitable treatment.
第二，它们应该用于治疗那些没有适宜治疗方法且对生命有威胁的疾病。
In other words, the heart behind this is to help people to be as healthy as possible,
换句话说，其中心是帮助人们尽可能健康，
just like other types of medicine — not to, say, genetically engineer an X-Man.
就像是其他类型的药物一样—而不是将人们基因改造成X-Man。
The general consensus of other ethics committees has been along the same lines.
其他伦理委员会的普遍共识一直是一致的。
Still, even with guidelines in place, most of these therapies are currently too risky to try in human fetuses,
虽然有指导方针，但现阶段大部分这些治疗方法都太过危险，所以不能在人类胚胎中进行尝试，
so research has mostly been confined to animal models.
因此大部分研究都限制于动物模型。
Pregnant people can get blood and tissue tests to determine if their child is likely to have a genetic disease
孕妇可以进行血液和组织检测以确定他们的孩子是否可能患有遗传病
including cystic fibrosis, hemophilia, and sickle cell anemia.
如囊胞性纤维症、血友病以及镰状细胞性贫血。
But there are not many immediate options if those tests are positive. We are making progress, though.
但如果检测为阳性，也没有很多直接的选择。虽然我们正在取得进展。
In 2018, a promising study in Nature Medicine showed
2018年，《Nature Medicine》中一项有希望的研究展现了
how fetal gene therapy could treat an illness in mice that is similar to Gaucher's disease in humans.
胚胎基因治疗可以如何治疗老鼠身上的一种疾病，这种病类似于人类的高歇氏病。
Gaucher's is an inherited disorder that causes an enzyme deficiency — specifically, for an enzyme called glucocerebrosidase.
高歇氏病是一种遗传病会造成酶缺损—尤其是一种被称为葡糖脑苷脂酶的酶。
Without healthy levels of it, waste builds up in the body, which can lead to all kinds of trouble.
没有健康含量的这种酶，废物会堆积在身体中导致各种问题。
Often, this disease can be treated by getting weekly enzyme injections, but a certain type of Gaucher's — type 2 — isn't treatable.
通常这种疾病可以通过每周注射酶来治疗，但是有一种类型的高歇氏病—2型—是不可治愈的。
In this type, there isn't enough glucocerebrosidase in the brain.
在这种类型中，大脑缺乏足量的葡糖脑苷脂酶。
And because of the blood-brain barrier that filters out most molecules, the enzyme injections don't work.
由于血脑屏障会过滤掉大部分分子，所以酶注射是没有用的。
The disease is often fatal, and by the time a baby is born, a lot of the damage has already been done.
这种疾病通常是致命的，婴儿出生时，很多损害就已经造成了。
So researchers have been looking into how to treat it using fetal gene therapy.
所以研究人员一直在寻求如何利用胚胎基因治疗治愈这种疾病。
In the 2018 experiment, scientists injected the brains of fetal mice with vectors full of instructions to make that missing enzyme and it seemed to help!
在2018年的实验中，科学家向胎鼠的大脑中注射了携带指令的载体以弥补那些缺失的酶，并且似乎有所帮助！
The mice had relatively normal enzyme activity, although they did tend to weigh less and didn't perform as well on movement tests.
这些老鼠酶活动相对正常，虽然它们体重更轻，在运动测试中表现也不太好。
A follow-up experiment seemed to be even more encouraging.
后续的试验似乎更鼓舞人心。
In it, researchers injected the vectors into the bloodstream instead of the brain.
在后续试验中，将载体注射至血液而非大脑中。
The mice were only allowed to be kept alive for 55 days for ethical reasons,
由于伦理原因，老鼠仅被允许存活55天，
but during that time, they didn't seem to be any different from regular mice.
但在此期间内，它们似乎没有任何异常之处。
The team also showed that this vector-injecting method worked on larger animal fetuses, like macaques.
团队也表示这种载体注射方法对更大型动物胚胎，如猕猴也有效。
The study was so successful that some scientists argue we are ready to start clinical trials of this method in humans.
该研究非常成功，因此一些科学家认为我们已经准备好了，可以对人类进行这种方法的临床试验。
But others disagree, pointing out that success in pre-clinical studies doesn't always equal success in clinical trials.
但是其他人则不同意，他们指出临床前研究的成功并不总是等同于在临床试验中的成功。
So they think we need to keep researching.
所以他们认为我们需要继续研究。
Because that's the thing about fetal gene therapy: It's really complicated, both scientifically and ethically.
因为胚胎基因治疗在科学和道德上都真的非常复杂。
After all, as soon as you start clinical trials, treating human embryos or fetuses that will develop into full-grown kids, you're dealing with a person's life.
毕竟，一旦你开始临床试验，治疗将发育完成儿童的人类胚胎或胎儿，你手上的就是一条人命。
And that's not something to be taken lightly.
这是不能轻视的。
We have done trials on fetuses before, but only using methods that were heavily studied and shown to be safe.
我们之前已经对胎儿进行过试验，但使用的方法都是经过大量研究且被证明是安全的。
Like, in another 2018 study, published in The New England Journal of Medicine,
例如，在2018年发表于《新英格兰医学期刊》的另一项研究中
researchers used fetal gene therapy to prevent XLHED — an inherited disorder that impairs sweat glands — in three babies.
研究人员使用胚胎基因方法预防三名婴儿的X连锁隐性遗传（XLHED）—一种会损害汗腺的遗传疾病
The kids were around a year and a half old when the paper was published, and seemed to be doing okay.
论文发表时，这些孩子约为一岁半左右，这么做似乎没问题。
The key was that the researchers were using extensively tested methods, and also got permission from their hospital's ethics committee.
关键是研究人员使用了经广泛测试的方法，并且得到了他们医院伦理委员会的同意。
That's very different from the news that broke just a few months later,
这和几个月后的新闻非常不同，
when it came out that a Chinese researcher had altered human embryos using CRISPR, a newer gene-editing technique.
事实证明一名中国研究人员使用的是CRISPR—一种更新的基因编辑技术
This trial violated most of the accepted ethical guidelines.
这个试验违反了普遍可接受的伦理准则。
For one, it was done to reduce the babies' chances of contracting HIV, and there are much less risky ways to do that.
例如，该试验是为了减少婴儿感染HIV的几率，但减少HIV患病几率还有很多风险更小的方式。
The scientist also didn't get permission from a committee, and, most importantly, the method he used isn't established as safe.
该名人员也没有得到委员会的同意，最重要的是，他使用的这种方法并不确定是安全的。
CRISPR has done great in the lab, but it's also been shown to cause occasional, accidental mutations.
CRISPR在实验室中表现不错，但它也会引起临时意外突变。
Thankfully, the kids are healthy so far, but that doesn't mean they always will be.
还好，到目前为这这些孩子是健康的，但这并不意味着他们会一直如此。
So, let's just say there's a reason we have these guidelines.
所以说这些道德准则的存在是有理由的。
In the future, there will likely be a time when we can safely edit an embryo's genome in all kinds of different ways.
未来我们或许可以安全地用各种方式编辑胚胎的基因组。
But even when that day comes, there will be other things to think about, too.
但是即便那一天到来了，还有其他事情需要考虑。
Like, what would the consequences be if someone's edited genes were passed to their offspring?
比如，如果某人的编辑基因遗传给了他们的后代会怎样？
Or if the edited gene mutated over the course of someone's life?
或者如果编辑基因发生突变会怎么样？
And then there are even messier questions, like how far is too far when it comes to gene editing,
还有甚至更加麻烦的问题，比如，基因编辑的底线在哪里，
and if this science is interfering with evolution… or if it matters if it is.
这种科学是否会妨碍进化...又或者如果会的话，会不会产生重要影响。
The most we can say is that, right now, fetal gene therapy is really only intended for necessary treatments.
现在我们知道的是胚胎基因治疗真的只能用于必要治疗。
The next steps are to continue the animal tests scientists have already started,
接下来是继续科学家们已经开始的动物测试，
to really understand how this science works and what the risks are.
才能真正了解这项科学如何起作用并且其风险有哪些。
Because at the end of the day, when these experiments are approved for more frequent clinical trials in humans,
因为最终，当这些实验得以通过可以对人体进行更加频繁的临床试验时，
we want to make sure they are as safe as possible.
我们希望确保他们尽可能安全。
If you're interested in keeping up with the latest research,
如果你对最新研究感兴趣，
you should check out the new patient education portal from the American Society of Gene and Cell Therapy.
你应该看看美国基因与细胞治疗学会的新病人教育入门网站。
It's a super comprehensive resource for everything you've ever wanted to know about the different types of gene therapy,
上边资源非常广泛，你可以了解各种不同类型的基因治疗、
how they work, and both past and ongoing research into all kinds of treatments.
它们的工作原理，以及过去和现在对各种治疗的研究。
And it is completely free. To check it out for yourself, just head over to asgct.org/education, or follow the link in the description below.
而且都是免费的。登陆asgct.org/education进行观看或是点击下方链接。
