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As humans, it's in our nature
翻訳: Reiko Bovee 校正: Eriko T
to want to improve our health and minimize our suffering.
誰もが 健康を改善したり
Whatever life throws at us,
肉体的苦しみを最小限に留め
whether it's cancer, diabetes, heart disease,
我が身に起る事が
or even broken bones, we want to try and get better.
癌 糖尿病 心臓病または骨折と
Now I'm head of a biomaterials lab,
それが何であろうと 良くなりたいと思うものです
and I'm really fascinated by the way that humans
私は生体材料研究所の所長ですが
have used materials in really creative ways
過去 様々な材料が 独創的な方法で人体に
in the body over time.
使われてきたということに
Take, for example, this beautiful blue nacre shell.
とても感心させられます
This was actually used by the Mayans
例えば この貝の青い真珠層をご覧下さい
as an artificial tooth replacement.
これはマヤ族が歯のインプラントに
We're not quite sure why they did it.
実際 使っていました
It's hard. It's durable.
その理由はよく分かりませんが
But it also had other very nice properties.
硬く長持ちし
In fact, when they put it into the jawbone,
他にもとても良い特質があります
it could integrate into the jaw,
顎に入れると
and we know now with very sophisticated
顎骨と融合するのです
imaging technologies
高度画像技術で
that part of that integration comes from the fact
分かっている
that this material is designed
融合の理由は この材料の
in a very specific way, has a beautiful chemistry,
用途によく合ったデザイン
has a beautiful architecture.
そして素晴らしい化学的性質と
And I think in many ways we can sort of think
構造にありました
of the use of the blue nacre shell and the Mayans
あらゆる意味で
as the first real application
マヤ族の青い真珠層を持つ貝の使い道は
of the bluetooth technology.
まさしく最初の
(Laughter)
ブルートゥース技術だ なんて思ったりします
But if we move on and think throughout history
(笑)
how people have used different materials in the body,
先に進んで 歴史を通して
very often it's been physicians
人類が体に様々な種類の材料を 使ってきたことを考えてみると
that have been quite creative.
創意工夫をしてきたのは 医師の場合が多く
They've taken things off the shelf.
彼らが様々な発明をしてきました
One of my favorite examples
その中でも 私のお気に入りは
is that of Sir Harold Ridley,
サー・ハロルド・リドリーのものです
who was a famous ophthalmologist,
彼は有名な眼科医で—
or at least became a famous ophthalmologist.
少なくとも そうなったのですが—
And during World War II, what he would see
第2次世界大戦中 彼は
would be pilots coming back from their missions,
戦線から戻って来たパイロットを見て
and he noticed that within their eyes
彼らの目の中に
they had shards of small bits of material
小さな異物のかけらが 入っているのに気がつきました
lodged within the eye,
興味深いことに
but the very interesting thing about it
その物質は炎症反応を
was that material, actually, wasn't causing
全く引き起こしていなかったのでした
any inflammatory response.
調べて分かったことは
So he looked into this, and he figured out
その物質は 小さなプラスチックのかけらで
that actually that material was little shards of plastic
スピットファイア戦闘機の天蓋から 来る物でした
that were coming from the canopy of the Spitfires.
それで彼はこの物質を
And this led him to propose that material
新しい眼内レンズの素材 として提唱したのです
as a new material for intraocular lenses.
PMMAと呼ばれるもので
It's called PMMA, and it's now used
毎年 何百万人の人の目に
in millions of people every year
白内障を防ぐ為に使われています
and helps in preventing cataracts.
この例は
And that example, I think, is a really nice one,
昔は機械的機能をさせる為に
because it helps remind us that in the early days,
よく生体不活性材料が 選ばれ
people often chose materials
使われていた ということを 示しています
because they were bioinert.
生体不活性材料を体に入れても
Their very purpose was to perform a mechanical function.
拒絶反応はありません
You'd put them in the body
しかし ここで私が述べたい事は
and you wouldn't get an adverse response.
再生医療は
And what I want to show you is that
生体不活性材料から
in regenerative medicine,
全く離れたということです
we've really shifted away from that idea
我々が積極的に探している材料は
of taking a bioinert material.
生体と作用する 生体活性材料で
We're actually actively looking for materials
生体内に入れられると
that will be bioactive, that will interact with the body,
そこで機能し
and that furthermore we can put in the body,
時が経つにつれ 生体内に吸収されるものです
they'll have their function,
このチャートをご覧下さい
and then they'll dissolve away over time.
これが示しているのは
If we look at this schematic,
細胞組織工学の 典型的アプローチです
this is showing you what we think of
普通患者から細胞を取り
as the typical tissue-engineering approach.
それを材料に入れ
We have cells there, typically from the patient.
非常に複雑なものに することもでき—
We can put those onto a material,
実験室で増殖するか
and we can make that material very complex if we want to,
患者の体に直接 戻すか どちらでもできます
and we can then grow that up in the lab
これが世界中で そして
or we can put it straight back into the patient.
我々の実験室でも 行われている方法です
And this is an approach that's used all over the world,
幹細胞について 本当に大切なことの1つは
including in our lab.
幹細胞は あらゆる組織に分化でき
But one of the things that's really important
又 そうなる傾向にあるので
when we're thinking about stem cells
幹細胞を入れる環境に
is that obviously stem cells can be many different things,
我々が必要な情報を 確実に組み込むと
and they want to be many different things,
目的の特定の組織に なるという事です
and so we want to make sure that the environment
世界中の実験室で 再生が試みられている組織のタイプは
we put them into has enough information
殆ど考え得る全ての組織 と言っていい程です
so that they can become the right sort
そんな組織の構造は
of specialist tissue.
かなり多様で
And if we think about the different types of tissues
患者の他の 隠れた病気とか健康問題が
that people are looking at regenerating
組織の再生法や
all over the world, in all the different labs in the world,
材料の使用法や
there's pretty much every tissue you can think of.
生化学的性質、 機能
And actually, the structure of those tissues
その他多くの特質に影響し それにより 我々の対処法も大きく変わってきます
is quite different, and it's going to really depend
組織は其々 異なる再生能力があります
on whether your patient has any underlying disease,
ここで思い出すのが 可哀想なプロメテウス
other conditions, in terms of how
危なっかしい決断をした彼は
you're going to regenerate your tissue,
ギリシャの神々に罰せられ
and you're going to need to think about the materials
岩に縛り付けられ 鷲が毎日
you're going to use really carefully,
彼の肝臓をついばみに来ます
their biochemistry, their mechanics,
彼の肝臓は毎日再生し
and many other properties as well.
そうやって来る日も来る日も
Our tissues all have very different abilities to regenerate,
永遠に神々に罰せられるのです
and here we see poor Prometheus,
肝臓はこのように 再生されることになるでしょうが
who made a rather tricky career choice
他の組織
and was punished by the Greek gods.
例えば軟骨は
He was tied to a rock, and an eagle would come
どんな些細な欠損でも
every day to eat his liver.
再生するのは とても難しいのです
But of course his liver would regenerate every day,
この様に組織により 違いが非常に大きく
and so day after day he was punished
骨の再生能力はその中間です
for eternity by the gods.
骨は我々の実験室で よく扱われる組織の1つで
And liver will regenerate in this very nice way,
自己修復能力は 実は かなり高いのです
but actually if we think of other tissues,
そうでなければ困ります たぶん我々はみな
like cartilage, for example,
骨折を経験しているでしょうし
even the simplest nick and you're going to find it
骨折治療の1つの方法は
really difficult to regenerate your cartilage.
「腸骨採取」と呼ばれる手法で
So it's going to be very different from tissue to tissue.
外科医が
Now, bone is somewhere in between,
腸骨から骨を採取し
and this is one of the tissues that we work on a lot in our lab.
ここにありますが—
And bone is actually quite good at repairing.
体の他の部分にそれを移植します
It has to be. We've probably all had fractures
これは本当にうまく行くのです
at some point or other.
本人の骨なので
And one of the ways that you can think
うまく血管新生化し
about repairing your fracture
血液の流れが とても良くなるのですが
is this procedure here, called an iliac crest harvest.
問題は採骨できる量に 限界があるという事です
And what the surgeon might do
その上 手術後 採骨した場所が
is take some bone from your iliac crest,
2年経っても
which is just here,
非常に痛む可能性があるのです
and then transplant that somewhere else in the body.
それで我々が考えた事は
And it actually works really well,
勿論 骨修復の需要は 非常に大きいのですが—
because it's your own bone,
腸骨タイプのアプローチでは
and it's well vascularized,
限界があまりにあるので
which means it's got a really good blood supply.
必要に応じ 生体内で
But the problem is, there's only so much you can take,
骨を再生し 移植したらどうだろう
and also when you do that operation,
それにより腸骨採取後のような
your patients might actually have significant pain
極度の痛みが伴わない移植が
in that defect site even two years after the operation.
出来るのではないだろうか? ということです
So what we were thinking is,
その我々のやり方は
there's a tremendous need for bone repair, of course,
典型的な細胞組織工学の アプローチに戻ったのですが
but this iliac crest-type approach
かなり違った観点を取りました
really has a lot of limitations to it,
随分 簡素化して
and could we perhaps recreate
かなりステップを省きました
the generation of bone within the body
患者からの 細胞採取の必要性
on demand and then be able to transplant it
あらゆる高価な 化学薬品の必要性
without these very, very painful aftereffects
そして研究室で担体を
that you would have with the iliac crest harvest?
培養する必要性を なくしました
And so this is what we did, and the way we did it
我々が本当に 焦点を置いているのは
was by coming back to this typical tissue-engineering approach
材料系と それを簡素化する事ですが
but actually thinking about it rather differently.
よく考えられた方法で使用したので
And we simplified it a lot,
このアプローチによって
so we got rid of a lot of these steps.
膨大な量の骨を 再生できたのです
We got rid of the need to harvest cells from the patient,
それで我々は生体を
we got rid of the need to put in really fancy chemistries,
骨を大量に作る為の
and we got rid of the need
媒体として使いました
to culture these scaffolds in the lab.
そのアプローチを
And what we really focused on
「生体バイオリアクター」と呼び このやり方で
was our material system and making it quite simple,
とてつもない量の骨を 再生できるのです
but because we used it in a really clever way,
分かり易く説明すると
we were able to generate enormous amounts of bone
こうです
using this approach.
生体には幹細胞の層が
So we were using the body
長骨の外側にあり
as really the catalyst to help us
「骨膜」とよばれ
to make lots of new bone.
普段とても
And it's an approach that we call
しっかりと その下の骨に密着していて
the in vivo bioreactor, and we were able to make
幹細胞を含んでいます
enormous amounts of bone using this approach.
この幹細胞は
And I'll talk you through this.
胎芽の成長にとても重要で
So what we do is,
骨折すると
in humans, we all have a layer of stem cells
骨を修復しようと活性化します
on the outside of our long bones.
我々はその骨膜に目をつけ
That layer is called the periosteum.
その下に液体を 注入する方法を開発しました
And that layer is actually normally
その液体は注入後30秒内で
very, very tightly bound to the underlying bone,
固形のゲルになり