How to grow a bone - Nina Tandon

Kako razviti kost - Nina Tandon

Prevoditelj: Vanja Kovac Recezent: Ivan Stamenković

Can you grow a human bone outside the human body?

Možete li razviti ljudsku kost izvan ljudskog tijela?

The answer may soon be yes,

Odgovor uskoro može biti da,

but before we can understand how that's possible,

ali prije nego objasnimo kako je to moguće,

we need to look at how bones grow naturally inside the body.

moramo pogledati kako kosti prirodno rastu unutar tijela.

Most bones start in a growing fetus as a soft, flexible cartilage.

Većina kosti započinje kao meka i fleksibilna hrskavica rastućeg fetusa

Bone-forming cells replace the cartilage with a spongy mineral lattice

Koštane stanice zamjenjuju hrskavicu sa spužvastom mineralnom rešetkom

made of elements like calcium and phosphate.

napravljenom od elemenata kao što su kalcij i fosfat.

This lattice gets harder, as osteoblasts,

Rešetka postaje snažnija, kako oteoblasti,

which are specialized bone-forming cells,

koji su specijalizirane koštane stanice,

deposit more mineral, giving bones their strength.

nanose više minerala i tako osnažuju kosti.

While the lattice itself is not made of living cells,

Iako sama rešetka nije napravljena od živih stanica,

networks of blood vessels, nerves and other living tissues

mreže krvnih žila, živaca i ostalog živog tkiva

grow through special channels and passages.

rastu kroz posebne kanale i prolaze.

And over the course of development,

I u tijeku razvoja,

a legion of osteoblasts reinforce the skeleton

mnoštvo osteoblasta ojačava kostur

that protects our organs, allows us to move,

koji štiti naše organe, dopušta nam kretanje,

produces blood cells and more.

proizvodi krvne stanice i više.

But this initial building process alone

Ali sam ovaj proces izgradnje

is not enough to make bones strong and functional.

nije dovoljan kako bi kosti bile jake i funkcionalne.

If you took a bone built this way,

Ako uzmete ovako izgrađenu kost,

attached muscles to it,

dodate na nju mišiće,

and tried to use it to lift a heavy weight,

i pokušate podići teški uteg,

the bone would probably snap under the strain.

kost bi vjerojatno puknula pod pritiskom.

This doesn't usually happen to us

To nam se inače ne događa

because our cells are constantly reinforcing

zbog toga što se naše stanice konstantno osnažuju

and building bone wherever they're used,

i izgrađuju kost gdje god je istrošena.

a principle we refer to as Wolff's Law.

po principu koji nazivamo Wolffov zakon.

However, bone materials are a limited resource

Bilo kako bilo, koštani materijal je ograničen

and this new, reinforcing bone

a nova, jača kost

can be formed only if there is enough material present.

može biti formirana samo ako imamo dovoljno materijala.

Fortunately, osteoblasts, the builders,

Na sreću, osteoblasti, graditelji,

have a counterpart called osteoclasts, the recyclers.

imaju duplikat, zvan osteoklasti, reciklatori.

Osteoclasts break down the unneeded mineral lattice using acids and enzymes

Osteoklasti kidaju nepotrebne mineralne rešetke koristeći kiseline i enzime

so that osteoblasts can then add more material.

tako da osteoblasti mogu dodati više materijala.

One of the main reasons astronauts must exercise constantly in orbit

Jedan od glavnih razloga zašto astronauti u orbiti moraju vježbati

is due to the lack of skeletal strain in free fall.

je manjak koštanog napora pri slobodnom padu.

As projected by Wolff's Law,

Kako je naznačeno u Wolffovom zakonu,

that makes osteoclasts more active than osteoblasts,

to čini osteoklaste aktivnijima od osteoblasta,

resulting in a loss of bone mass and strength.

razultirajući u gubitku koštane mase i snage.

When bones do break, your body has an amazing ability

Kada kosti ipak puknu, vaše tijelo ima nevjerojatnu mogućnost

to reconstruct the injured bone as if the break had never happened.

rekonstrukcije ozlijeđene kosti kao da do loma nikada nije došlo.

Certain situations, like cancer removal,

Neki događaji, kao rak,

traumatic accidents,

traumatične nezgode,

and genetic defects exceed the body's natural ability for repair.

i genetski nedostatci prekoračuju prirodnu mogućnost obnove tijela.

Historical solutions have included filling in the resulting holes with metal,

Povijesna riješenja uključuju popunjavanje nastalih praznina metalom,

animal bones,

životinjskim kostima,

or pieces of bone from human donors,

ili komadićima kostiju ljudskih donora,

but none of these are optimal as they can cause infections

ali niti jedno od njih nije optimalno, jer mogu uzrokovati infekcije

or be rejected by the immune system,

ili mogu biti odbijeni od strane imunoločkog sustava,

and they can't carry out most of the functions of healthy bones.

i ne mogu odraditi većinu funkcija zdrave kosti.

An ideal solution would be to grow a bone made from the patient's own cells

Idealno riješenje bilo bi razviti kost iz stanica pacijenta

that's customized to the exact shape of the hole,

koja je precizno prilagođena obliku praznine,

and that's exactly what scientists are currently trying to do.

a to je točno ono što znanstvenici trenutno pokušavaju napraviti.

Here's how it works.

Evo kako to radi.

First, doctors extract stem cells from a patient's fat tissue

Prvo, liječnici izvuku matične stanice iz pacijentova masnog tkiva

and take CT scans to determine the exact dimensions of the missing bone.

i naprave CT kako bi odredili točne dimenzije praznine u kosti.

They then model the exact shape of the hole,

Tada naprave model u obliku praznine,

either with 3D printers,

ili sa 3D printerima,

or by carving decellularized cow bones.

ili obrađujući umjetne kravlje kosti.

Those are the bones where all of the cells have been stripped away,

To su kosti kojima su uklonjene sve stanice,

leaving only the sponge-like mineral lattice.

ostavljajući jedino spužvastu mineralnu rešetku.

They then add the patient's stem cells to this lattice

Oni tada dodaju pacijentove matične stanice u tu rešetku

and place it in a bioreactor,

i stave je u bioreaktor,

a device that will simulate all of the conditions found inside the body.

uređaj koji simulira sve uvijete koje imamo unutar tijela.

Temperature, humidity, acidity and nutrient composition

Temperatura, vlažnost, kiselost i sastav hranjivih tvari

all need to be just right for the stem cells to differentiate

moraju biti ispravni kako bi se matične stanice razvile

into osteoblasts and other cells,

u osteoblaste i druge stanice,

colonize the mineral lattice,

nastanile mineralnu rešetku,

and remodel it with living tissue.

i oblikovale je sa živim tkivom.

But there's one thing missing.

Ali nedostaje jedna stvar.

Remember Wolff's Law?

Sjećate se Wollfova zakona?

An artificial bone needs to experience real stress,

Umjetna kost treba osjetit pravi pritisak,

or else it will come out weak and brittle,

inače će biti slaba i lomljiva,

so the bioreactor constantly pumps fluids around the bone,

zato bioreaktor konstantno utiskuje fluide oko kosti,

and the pressure tells the osteoblasts to add bone density.

i pritisak govori osteoblastima da poprave gustoću kosti.

Put all of this together, and within three weeks,

Stavite ovo sve zajedno, i u roku tri tjedna,

the now living bone is ready to come out of the bioreactor

sada živa kost spremna je izaći iz bioreaktora

and to be implanted into the patient's body.

i biti ugrađena u tijelo pacijenta.

While it isn't yet certain that this method will work for humans,

Iako još nije sigurno da će ova metoda biti dobra za ljude,

lab grown bones have already been successfully implanted in pigs

kosti uzgojene u laboratoriju već su uspješno ugrađene u svinje

and other animals,

i u druge životinje,

and human trials may begin as early as 2016.

a testiranja na ljudima mogu početi već 2016.

Predavanje: Nina Tandon Naracija: Nina Tandon

Animacija Giant Animation studio www.giant.ie

TEDEd Puno predavanje na ed.ted.com