Do Gut Microbes Control Your Personality? | Kathleen McAuliffe | TED

翻译人员: Xinrong Wu 校对人员: Laixi Kang

We've been debating the question forever.

我们一直在辩论这个问题。

Is there such a thing as free will?

有自由意志之类的东西吗？

Am I captain of my ship?

我是我的船的船长吗？

Master of my own destiny?

我是我自己命运的主人吗？

I'm no philosopher.

我不是哲学家。

Biology is my realm and from where I stand,

生物学是我的领域，从我的角度来看，

there is clearly more than one of us at the helm.

显然有不止一个人掌舵。

I'm referring to the fact

我指的是，

that half the cells in your body do not contain your own DNA.

你体内有一半的细胞不含你自己的DNA。

They belong to bacteria, protozoa, fungi

它们属于细菌、原生动物、真菌

and other unicellular creatures.

和其他单细胞生物。

These tiny tenants, collectively known as our microbiota,

这些微小租户，统称为人体微生物群，

are most abundant in the gut,

在肠道中最为丰富，

where they aid in digestion

它们有助于消化

and carry out many other essential functions.

并发挥许多其他基本功能。

Most amazing, they "talk" to your brain.

最神奇的是， 它们与你的大脑 “说话”。

They influence your mood,

它们会影响你的心情、

your energy level, your appetite,

能量水平、食欲、

your memory,

记忆力，

perhaps even your personality.

甚至是你的个性。

I can say this with confidence

我可以自信地说这句话，

owing to mice like this, which have no microbes.

因为像这样的老鼠没有微生物,

They've been dubbed bubble mice

它们被称为泡泡老鼠，

because they're raised in sterile facilities.

因为它们是在无菌设施中长大的。

Contrast their behavior to that of a normal mouse,

将它们的行为与 普通小鼠的行为进行对比，

which is colonized at birth with microbes,

后者在出生时就被微生物定植，

and you'll notice striking differences.

你会发现惊人的差异。

A normal mouse is a quick and eager learner.

普通小鼠好奇，学习能力强。

Show it a novel object, like a napkin ring,

给它看一个新颖的物体，比如餐巾圈，

and it will circle and sniff it with great interest.

它会围着这个物体转圈， 兴致勃勃地闻一闻。

Place it in a maze and it's keen to explore new passages

把它放在迷宫里，它就会热衷 于探索新的通道，

and remembers where it's been.

并记住它去过的地方。

A bubble mouse could not be more different.

泡泡鼠则截然不同。

It lacks natural curiosity.

它缺乏天生的好奇心。

It's slow to learn, quick to forget,

它学习起来很慢，很快就会忘记，

and just as inclined to favor the familiar

同样倾向于偏爱熟悉的事物，

over what's new, exciting, or different.

而不是新的、令人兴奋的或不同的东西。

Indeed, they don't even protest

事实上，如果他们年轻时与母亲分离，

if separated at a young age from their mothers,

他们甚至不会抗议，

a trauma that in a normal mouse would lead to lifelong skittishness.

这种创伤在普通老鼠身上 会导致终生的紧张倾向。

But if you colonize a bubble mouse early in life

但是，如果你在生命的早期

with the normal microbiota for that strain,

用该菌株的正常微生物群 来定植泡泡鼠，

guess what happens?

猜猜会发生什么？

Their behavior normalizes.

它们的行为会正常化。

We're not mice.

我们不是老鼠。 那么这些都适用于我们吗？

So does any of this apply to us?

Actually a mountain of evidence suggests that it does.

实际上，大量的证据表明确实如此。

Consider this.

考虑一下。

If I transfer gut bacteria from an overweight twin to bubble mice,

如果我将肠道细菌 从超重的双胞胎转移到泡泡鼠身上，

the animals fatten up.

它们就会发胖。

Transfer gut bacteria from a thin twin to bubble mice,

将苗条的双胞胎的肠道细菌 转移到泡泡鼠身上，

feed them the same rat chow and the animals stay thin.

给它们喂同样的食物， 它们就会保持苗条状态。

Similarly, if I transfer gut bacteria from a depressed person

同样，如果我将肠道细菌 从抑郁症患者转移

to a bubble mouse,

到泡泡鼠身上，

the animal will display depressive-like symptoms.

它会表现出类似抑郁症的症状。

For example, if placed in a water tank,

例如，如果放置在水箱中，

it stops swimming sooner than a mouse that receives gut bacteria

它会比接收非抑郁症患者的肠道细菌

from a non-depressed person.

的老鼠更快地停止游泳。

That mouse will keep trying to escape.

后者会一直试图逃跑。

It's not so quick to give in to despair.

向绝望屈服还没那么快。

How in the world can gut bacteria influence how we feel and act?

肠道细菌到底如何 影响我们的感受和行为？

They have many techniques, actually.

实际上，它们有很多技巧。

But here's one of their coolest.

但这是最酷的一个。

Gut bacteria produce hoards of psychoactive compounds,

肠道细菌会产生大量的精神活性化合物，

including half a dozen neurotransmitters.

包括六种神经递质。

Put simply, gut bacteria can talk to the brain because we,

简而言之，肠道细菌 可以与大脑交谈，因为我们，

meaning our microbes and human cells,

即我们的微生物和人体细胞，

all speak the same language.

都说相同的语言。

In fact, some scientists think

实际上，一些科学家认为

this language was actually invented by bacteria.

这种语言实际上是由细菌发明的。

I should point out that this long-distance conversation

我应该指出，这种长途对话

is facilitated by a major nerve cable that runs from your gut to your brain.

是由一条从肠道延伸到 大脑的主要神经电缆促进的。

It's called the vagus nerve,

它被称为迷走神经，

and it can be directly activated by bacteria

它可以直接被细菌

or by the psychoactive compounds they produce.

或它们产生的精神活性化合物激活。

Incidentally, about 80 percent of the traffic on this cable

顺便说一句，这条电缆上 约有 80％ 的流量

is going from the gut to the brain and not the other way around,

是从肠道流向大脑， 而不是像人们长期以来所假设

as had long been assumed.

的那样反过来。

Of course, gut bacteria can also rely on the circulatory system

当然，肠道细菌也可以依靠循环系统

to transport their psychoactive compounds upstairs.

将其精神活性化合物运送到大脑。

And there's one other very important, albeit indirect way

还有一种非常重要的， 尽管是间接的方式，

that gut bacteria signal the brain.

助肠道细菌向大脑发出信号。

And that's by misbehaving.

那就是通过行为不端。

When aggressive bacteria invade the gut wall,

当侵略性细菌侵入肠壁时，

immune cells rush to the scene

免疫细胞会冲到现场，

and surprising scientists,

令科学家惊讶的是，

those immune cells and related compounds don't always stay localized in the gut,

这些免疫细胞和相关化合物 并不总是局限在肠道中，

but can travel to the brain

而是会进入大脑，

where they trigger inflammation and depression.

引发炎症和抑郁症。

For reasons that are not well understood,

由于尚不为人知的原因，

inflammation and depression often go hand in hand.

炎症和抑郁通常是齐头并进的。

They're a destructive duo.

它们是破坏性的二人组。

Interestingly, a rapidly advancing treatment for mental disturbances

有趣的是，一种快速发展的 精神障碍治疗

is called vagus nerve stimulation, or VNS.

正好就是迷走神经刺激（VNS）。

As its name suggests,

顾名思义，

it entails electrically stimulating the vagus nerve

它需要通过植入胸部的电极 对迷走神经进行电刺激。

via an electrode implanted in the chest.

Although this therapy evolved independently of microbiota research,

尽管这种疗法是 独立于微生物群研究而发展起来的，

some scientists think

但一些科学家认为，

that the current may actually mimic the effects of gut bacteria

这种电流实际上可能模仿了肠道细菌

on the nerve.

对神经的影响。

That's speculative, but what is clear is that VNS strengthens the gut barrier,

这是推测性的，但显而易见的是，

VNS 可以增强肠道屏障，

preventing pathogenic bacteria from breaching it

防止致病细菌突破肠道屏障

and causing an inflammatory response that spreads to the brain.

并导致炎症反应扩散到大脑。

Encouragingly, the FDA has already approved VNS

鼓舞人心的是，美国食品药品管理局 已经批准 VNS

for the treatment of severe epilepsy

用于治疗对标准疗法无反应的 严重癫痫和抑郁症。

and depression unresponsive to standard therapy.

What's more, early clinical trials suggest

更重要的是，早期的临床试验表明，

the procedure may also benefit people suffering from ADHD, OCD and PTSD.

该疗法还可能使 患有注意力缺陷多动障碍、

强迫症和创伤后应激障碍的人受益。

In parallel with these developments,

在取得这些进展的同时，

microbiota researchers are attempting to treat mental disturbances

微生物群研究人员正试图

by changing the composition of our gut bacteria

通过改变肠道细菌的成分，

or alternatively,

或阻断这些生物产生的化学物质的作用 来治疗精神障碍。

by boosting or blocking the action of the chemicals these organisms make.

To that end,

为此，

they're making exciting progress

他们在查明各种神经精神疾病中

in pinpointing exactly which bacteria are good or bad actors

究竟哪些细菌是好是坏

in various neuropsychiatric conditions.

方面取得了令人兴奋的进展。

People with autism spectrum disorder, for example,

例如，自闭症谱系障碍患者的血液中

often have high amounts of a bacteria molecule in their blood,

通常含有大量的细菌分子，

and in rodents,

而在啮齿动物中，

this molecule has been shown to raise anxiety

这种分子已被证明会加剧焦虑，

and even alter brain connectivity.

甚至改变大脑的连通性。

Axial Therapeutics,

Axial Therapeutics，

a company at the forefront of developing microbiota-based treatments,

一家处于开发基于微生物群疗法 前沿的公司，

is now conducting a clinical trial of a drug

目前正在对一种

designed to prevent this destructive molecule

旨在防止这种破坏性分子

from reaching the brain.

进入大脑的药物进行临床试验。

The goal is to treat irritability in children with autism.

目标是治疗自闭症儿童的易怒表现。

Meanwhile, a bacterium found in yogurt called Lactobacillus reuteri

同时，酸奶中发现的一种 名为罗伊特氏乳杆菌的细菌

has shown to promote social bonding in animal models of autism.

已被证明可以促进 自闭症动物模型中的社交联系。

Both good and bad bacteria have similarly been linked

好细菌和坏细菌同样与

to amyotrophic lateral sclerosis, or ALS.

肌萎缩性侧索硬化症（ALS）有关。

That's the neurodegenerative disease

这是一种神经退行性疾病，

best known for paralyzing the great baseball player Lou Gehrig

使伟大棒球运动员卢·格里格

at the peak of his career.

在其职业生涯巅峰瘫痪。

Like him, most patients die within just a few years

像他一样，大多数患者在被诊断出 患有这种疾病后的短短几年内死亡。

of being diagnosed with the disease.

A small minority live ten years or longer.

一小部分人活十年或更长时间。

In animal models of ALS,

在肌萎缩性侧索硬化症的动物模型中，

Israeli researchers have recently discovered two bacteria

以色列研究人员最近发现了两种

that accelerate the disease

加速疾病的细菌，

and another that slows its development.

和另一种可以减缓其发展的细菌。

They suspect the benefits of the good bacteria

他们怀疑有益细菌的好处

are due to a vitamin that it produces, called nicotinamide.

归因于它产生的一种 叫做烟酰胺的维生素。

Microbiota researchers are making even greater progress

微生物群研究人员

in unraveling the root causes of Parkinson's disease.

在揭示帕金森氏病的根本原因 方面取得了更大的进展。

If you know the actor Michael J. Fox,

如果你认识演员迈克尔·福克斯， 如果你看过他的许多视频，

if you've seen many of his videos,

you'll know its symptoms are shaking,

你就会知道它的症状是颤抖、

stiffness and an unsteady gait.

僵硬和步态不稳定。

It's long been known that the disease involves the misfolding of a protein

众所周知，这种疾病涉及一种

called alpha-synuclein in this part of the brain.

叫做α-突触核蛋白的蛋白质 在大脑的这一部分的错误折叠。

As the misfolding spreads, brain cells start to die,

随着错误折叠的扩散， 脑细胞开始死亡，

symptoms worsen.

症状恶化。

The big mystery is, what causes alpha-synuclein,

最大的谜团是，最初 是什么原因导致了α-突触核蛋白，

the Parkinson's protein,

即帕金森氏蛋白，

to misfolded in the first place.

会被错误折叠。

Several labs have recently converged on one likely culprit.

最近，一些实验室聚焦 在一个可能的罪魁祸首上。

The guts of some people, their research suggests,

他们的研究表明，有些人的肠道中

harbor a strain of E. coli

含有一种大肠杆菌菌株，

that churns out a misfolded compound very similar to the Parkinson's protein.

这种菌株会产生一种与帕金森氏蛋白 非常相似的错误折叠化合物。

And when misfolded variants of this protein

而且，当这种蛋白质的错误折叠变体

are injected into the guts of susceptible rodents,

被注射到易感啮齿动物的肠道中时，

it causes the normal protein in the intestinal lining

它会导致肠道内膜中的正常蛋白质

to misfold in turn.

错误折叠。

Like falling dominoes,

就像倒下的多米诺骨牌一样，

this wave of misfolding proteins slowly spreads up the vagus nerve,

这波错误折叠的蛋白质会 慢慢地向迷走神经扩散，

and in about two months,

大约两个月后，

you see clumped up protein in exactly the part of the brain

你会看到结块的蛋白 出现在和帕金森氏症患者

that degenerates in Parkinson's patients.

大脑退化的部分相同的地方。

Most importantly,

最重要的是，

these fresh glimpses into the origins of the disease

这些对该疾病起源的新的了解

are suggesting new ways of intervening in its progression,

为干预其进展提供了新的方法，

a prospect, needless to say, that has experts super excited.

毫无疑问，专家们非常兴奋。

Of course, it's early days.

当然，现在还为时过早。

We don't yet know

我们还不知道这一系列研究

whether successful treatments will emerge from this line of research,

是否会带来成功的治疗方法，

or, for that matter,

或者就此而言，

any of the other investigations I've described.

我所描述的任何其他研究。

But I think you'll agree there's cause for optimism.

但我想你会同意有理由感到乐观。

If nothing else, I hope I've convinced you that your behavior is controlled

别的不说，我希望 我已经说服你，你的行为

not just from the top down,

不仅是自上而下的控制的，

but quite literally from the bottom up.

而且是从下往上控制的。

In short, the person you call "I" is really "we."

简而言之， 你称之为 “我”的人 实际上是 “我们”。

Thank you.

谢谢。

(Applause)

（掌声）