Why haven’t we cured arthritis? - Kaitlyn Sadtler and Heather J. Faust

譯者: Lilian Chiu 審譯者: Harper Chang

While regaling you with daring stories from her youth,

若沒告訴你她年輕時的大膽故事，

it might be hard to believe your grandmother used to be a trapeze artist.

可能很難相信你的祖母 曾經是個高空鞦韆表演者。

However, the bad backs, elbow pain, and creaky knees so common in older people

然而，老人常見的背痛、 手肘痛、膝蓋嘎嘎作響

is more than just “old age."

並不只是「老化」而已。

In fact, the source of this stiffness plagues many young people as well.

事實上，僵硬症狀的元兇 也會找上許多年輕人，

The culprit is arthritis:

它就是關節炎。

a condition that causes inflammation and pain in the joints

這是一種會造成 關節發炎和疼痛的疾病，

of over 90 million people in the U.S. alone.

光在美國就有超過 九千萬人有關節炎。

But are stiff, creaky joints really inevitable?

但，關節真的無可避免 會變僵硬、嘎嘎作響嗎？

What makes arthritis so pervasive,

是什麼讓關節炎如此普遍？

and why haven’t we found a cure for this widespread condition?

為什麼尚未找到方法 來治癒這種廣泛的疾病？

The first hurdle is that arthritis is actually a spectrum

第一個障礙是

「關節炎」其實是廣泛概念，

of over 100 different arthritic conditions.

其中包含超過一百種 不同的關節疾病。

All these conditions share symptoms of joint pain and inflammation,

所有這些疾病都有 關節痛和發炎的症狀，

but the origin and severity of those symptoms vary widely.

但那些症狀的原因 和嚴重程度卻非常不同。

Even the most common type, osteoarthritis,

就連最常見的骨關節炎，

is trickier to prevent than one might think.

也比一般人想像的要難預防。

It’s a general misconception that arthritis is confined to old age.

人們普遍認為關節炎 只在年老才會發生，

The origins of osteoarthritis can often be traced to a patient’s early life,

然而，骨關節炎的根源 通常能追溯到病人年輕時，

from any seemingly ordinary joint injury.

許多看似普通的關節傷害 最終導致了骨關節炎。

Following impact, immune cells rush in to help clean and repair the damaged site

在受到衝擊之後，免疫細胞

就會趕到患處協助清理和修復，

and begin pumping out enzymes,

並開始放出酵素，

including matrix metalloproteinases and aggrecanases.

包括基質金屬蛋白酶 及聚集蛋白聚糖酶。

These enzymes clear out the damaged tissue and contribute to inflammation.

這些酵素會清掉受損的組織， 並協助處理發炎。

But while this rapid swelling helps protect the joint during recovery,

雖然這種快速的腫脹 能在關節恢復期間協助保護關節，

inadequately healed tissue can cause these immune cells to overstay their welcome.

沒有妥當癒合的組織可能使 免疫細胞待太久而不受歡迎。

The continuing flood of enzymes starts to degrade the cartilage,

持續不斷湧入的酵素 開始讓軟骨退化，

weakening the joint and leading to arthritis later on.

讓關節變脆弱，導致後續的關節炎。

Not all forms of arthritis can simply be traced to an old sports injury.

並非所有形式的關節炎 都源於過去運動的舊傷。

Take rheumatoid arthritis, which affects 1.3 million U.S. adults.

以風濕性關節炎為例，美國 有一百三十萬成人為之所苦。

This condition is actually an autoimmune disease

它其實是一種自體免疫疾病，

in which autoantibodies target natively produced proteins,

自身抗體會錯誤的攻擊自身蛋白質。

some of which are secreted by cartilage cells.

其中有些蛋白質是軟骨細胞分泌的。

We still don’t know what causes this behavior,

我們還不知道這種行為的成因，

but the result is that the body treats joint tissue like a foreign invader.

但結果是身體視關節組織為外侮。

Immune cells infiltrate the joint despite there being no tissue damage to repair.

免疫細胞滲入關節， 儘管並沒有組織損傷需要修復。

This response leads to chronic inflammation,

這種反應會造成慢性發炎，

which destroys bone and cartilage.

進而摧毀骨頭和軟骨。

Yet another condition, spondyloarthritis,

還有一種疾病，脊椎關節炎，

has similarities to both of the conditions we’ve covered.

也具有我們所發現的兩種狀況。

Patients experience continuous inflammation in the joints

病人會持續發炎，發炎處包括關節

and at the sites where ligaments and tendons attach to bones,

及韌帶和肌腱附著在骨頭上的點，

even without any initial injury.

即使最初沒有任何受傷。

This leads to the flood of enzymes and degradation seen in osteoarthritis,

這就會造成骨關節炎中 大量酵素湧現及退化，

but is driven by different inflammatory proteins called cytokines.

但成因是不同的 發炎蛋白質，叫做細胞激素。

As the enzymes eat away at cartilage,

由於酵素不斷地蠶食軟骨，

the body attempts to stabilize smaller joints by fusing them together.

身體嘗試以熔接的方式 穩定比較小的關節。

This process sometimes leads to outgrowths called bone spurs,

這個過程有時會導致骨刺長出來，

which also cause intense stiffness and joint pain.

骨刺會造成強烈的僵硬和關節痛。

With so many factors causing arthritis,

造成關節炎的因子很多，

our current treatments are tailored to tackle specific symptoms

目前的治療方式主要 針對處理特定症狀，

rather than underlying causes.

而非針對背後成因。

These range from promising MACI techniques,

包括很被看好的 自體軟骨細胞移植技術，

which harvest cells from small pieces of cartilage to grow replacement tissue.

從小片的軟骨取得細胞， 用來長出取代用的組織。

To a technique called microfracture,

還有種方式叫微骨折手術，

where surgeons create small holes in the bone,

外科醫生會在骨頭上鑽出小孔，

allowing bone marrow stem cells to leak out and form new cartilage.

讓骨髓幹細胞可以 漏出來，形式新的軟骨。

As a last resort,

還有最後的防線， 如果軟骨不行了，

people with withered cartilage can even undergo full joint replacements.

還可以將整個關節置換。

But outside these drastic measures,

但除了這些極端的手段之外，

the underlying drivers of autoimmune arthritis

造成自身免疫關節炎的背後成因

still present a unique treatment challenge.

仍然是個很獨特的治療難題。

Scientists are making progress with therapies that block TNF-alpha,

科學家在研究能阻擋腫瘤壞死 因子－α 的治療上有些進展，

one of the primary proteins causing inflammation in rheumatoid arthritis.

在風濕性關節炎中，它是 造成發炎的主要蛋白質之一。

But even this approach only treats the symptoms of the condition, not the cause.

但就算是這個方法， 也只是針對症狀而非針對成因。

In the meantime, some of our best defenses against arthritis are lifestyle choices:

同時，

若要對抗關節炎， 有一些最好的預防做法

是選擇健康的生活方式，

maintaining a healthy weight to take pressure off joints,

保持健康的體重， 以免關節受過大壓力，

low-impact exercises like yoga or cycling, and avoiding smoking.

做低衝擊的運動，像瑜伽或騎車，

以及避免抽菸。

These arthritis-fighting behaviors can help us lead longer lives

這些對抗關節炎的行為 能幫助我們有更長的壽命，

as we continue to research cures and treatments

同時人類也會繼續 研究治療方式，

for the huge diversity of arthritic conditions.

來處理各類關節炎疾病。