What is Alzheimer's disease? - Ivan Seah Yu Jun

阿茲海默症（失智症）是什麼？ - Ivan Seah Yu Jun

譯者: Marssi Draw 審譯者: Regina Chu

Every four seconds,

平均每 4 秒

someone is diagnosed with

就有一個人被診斷罹患

Alzheimer's disease.

阿茲海默症

It's the most common cause of dementia,

那是失智最常見的成因

affecting over 40 million people worldwide,

影響全世界四千萬人

and yet finding a cure is something that still

至今尚未找到解方

eludes researchers today.

難倒許多研究人員

Dr. Alois Alzheimer, a German psychiatrist,

愛羅斯．阿茲海默 是一位德國的精神科醫師

first described the symptoms in 1901

最早在 1901 年首次提出這個症狀

when he noticed that a particular hospital patient

他注意到某位住院病患

had some peculiar problems,

有一些奇怪的問題

including difficulty sleeping,

包括睡眠困擾

disturbed memory, drastic mood changes,

記憶不正常、情緒劇烈變化

and increasing confusion.

日漸失智

When the patient passed away,

病人過世後

Alzheimer was able to do an autopsy

阿茲海默為她驗屍

and test his idea that perhaps

並檢驗他的想法

her symptoms were caused by irregularities

也許她的症狀是因為

大腦組織不完整而引起

in the brain's structure.

What he found beneath the microscope

他在顯微鏡底下發現

were visible differences in brain tissue

腦組織有顯而易見的差異

in the form of misfolded proteins

呈現出蛋白質的摺疊錯誤

called plaques,

稱為斑塊

and neurofibrillary tangles.

以及神經纖維纏結

Those plaques and tangles work together

那些斑塊和纏結共同運作

to break down the brain's structure.

破壞腦部組織

Plaques arise when another protein

斑塊產生是在另一個蛋白質

in the fatty membrane surrounding nerve cells

在環繞神經元的脂肪膜中

gets sliced up by a particular enzyme,

被一個特別的酶切割成片

resulting in beta-amyloid proteins,

導致 β-類澱粉蛋白

which are sticky and have a tendency

具黏性而且會

to clump together.

凝結成塊

That clumping is what forms the things

那種結塊

就是產生我們稱斑塊的東西

we know as plaques.

These clumps block signaling

這些結塊阻斷訊號傳遞

and, therefore, communication

即細胞間的溝通

between cells, and also seem to trigger

似乎也引起

immune reactions that cause the destruction

免疫反應

造成神經元的破壞

of disabled nerve cells.

In Alzheimer's disease, neurofibrillary tangles

阿茲海默症中的神經纖維纏結

are built from a protein known as tau.

由一種「tau 蛋白」所造成

The brain's nerve cells contain a network of tubes

大腦的神經元包含了微管的網絡

that act like a highway for food molecules

它的運作方式就像

供食物分子和其它東西用的公路

among other things.

Usually, the tau protein ensures that these tubes

通常，tau 蛋白會確保

are straight, allowing molecules

這些微管都是筆直的

to pass through freely.

讓分子自由通行

But in Alzheimer's disease,

但是在阿茲海默症中

the protein collapses into twisted strands or tangles,

蛋白質崩壞成扭曲的束狀或結塊

making the tubes disintegrate,

結成微管瓦解

obstructing nutrients from reaching the nerve cell

阻礙營養抵達神經元

and leading to cell death.

導致細胞死亡

The destructive pairing of plaques and tangles

這種斑塊和纏結的破壞性結合

starts in a region called the hippocampus,

從海馬迴開始

which is responsible for forming memories.

該區主責記憶的形成

That's why short-term memory loss

因此短期記憶消失

is usually the first symptom of Alzheimer's.

通常是阿茲海默症的首要症狀

The proteins then progressively invade

接著蛋白質日漸侵略

other parts of the brain,

大腦的其它部分

creating unique changes that signal

造成特別的變化

various stages of the disease.

顯示出這個疾病不同的階段

At the front of the brain,

在大腦的前側

the proteins destroy the ability to process logical thoughts.

蛋白質破壞處理邏輯思考的能力

Next, they shift to the region that controls emotions,

接下來，它們會轉向情緒控制區

resulting in erratic mood changes.

導致難以捉摸的情緒變化

At the top of the brain,

在大腦上方

they cause paranoia and hallucinations,

它們會造成偏執和幻覺

and once they reach the brain's rear,

當它們擴散到大腦後方

the plaques and tangles work together

斑塊和纏結會一起

to erase the mind's deepest memories.

刪除最深層的記憶

Eventually the control centers governing

最後，主宰心跳和呼吸的控制中心

heart rate and breathing are overpowered as well

也會被制伏

resulting in death.

最終導致死亡

The immensely destructive nature of this disease

這個疾病的極大破壞力

has inspired many researchers to look for a cure

讓許多研究人員急於找到解方

but currently they're focused on slowing its progression.

但是目前他們著眼在減緩病情

One temporary treatment

一次短暫治療

helps reduce the break down of acetylcholine,

就會幫助減緩乙醯膽鹼被破壞

an important chemical messenger in the brain

乙醯膽鹼是大腦中重要的傳導物質

which is decreased in Alzheimer's patients

這種物質在阿茲海默症的病患中減少

due to the death of the nerve cells that make it.

是因為產生它的神經元死亡

Another possible solution is a vaccine

另一種可能的解方是疫苗

that trains the body's immune system to attack

能訓練身體的免疫系統

beta-amyloid plaques before they can form clumps.

在 β-類澱粉蛋白斑結塊前攻擊它

But we still need to find an actual cure.

但是我們還是需要找一個真正的解方

Alzheimer's disease was discovered

阿茲海默症

more than a century ago,

早在一個世紀前就已發現

and yet still it is not well understood.

而且還未被完全了解

Perhaps one day we'll grasp

也許有一天我們會

the exact mechanisms at work behind this threat

在研究中找到這個威脅背後的準確機制

and a solution will be unearthed.

如此一來問題就會迎刃而解