How bones make blood - Melody Smith

Prevodilac: Stefan Vesić Lektor: Milenka Okuka

At any given moment, trillions of cells are traveling through your blood vessels,

Svakog trenutka, bilioni ćelija putuju kroz vaše krvne sudove,

sometimes circling the body in just one minute.

ponekad prolazeći celo telo za samo jedan minut.

Each of these cells has its origins deep in your bones.

Svaka od ovih ćelija potiče duboko u vašim kostima.

Bones might seem rock-solid, but they’re actually quite porous inside.

Možda se čini da su kosti tvrde kao kamen, ali su zapravo veoma šuplje iznutra.

Large and small blood vessels enter through these holes.

Veliki i mali krvni sudovi ulaze kroz te rupe.

And inside most of the large bones of your skeleton is a hollow core

Unutar većine velikih kostiju vašeg skeleta je šuplje jezgro

filled with soft bone marrow.

ispunjeno mekom koštanom srži.

Marrow contains fat and other supportive tissue,

Srž sadrži masti i drugo potporno tkivo,

but its most essential elements are blood stem cells.

ali njen najbitniji deo jesu matične krvne ćelije.

These stem cells are constantly dividing.

Ove matične ćelije se stalno dele.

They can differentiate into red blood cells,

Mogu se podeliti na crvena krvna zrnca,

white blood cells, and platelets,

bela krvna zrnca i trombocite

and send about hundreds of billions of new blood cells

i one šalju stotine milijardi novih krvnih ćelija

into circulation every day.

u krvotok svakog dana.

These new cells enter the bloodstream

Ove nove ćelije ulaze u krvotok

through holes in small capillaries in the marrow.

kroz rupe u malim kapilarima u koštanoj srži.

Through the capillaries,

Kroz kapilare,

they reach larger blood vessels and exit the bone.

one dolaze do većih krvnih sudova i izlaze iz kostiju.

If there’s a problem with your blood,

Ako postoji problem sa vašom krvlju,

there’s a good chance it can be traced back to the bone marrow.

postoji dobra šansa da koren problema leži u koštanoj srži.

Blood cancers often begin with genetic mutations in the stem cells.

Rak krvi uglavnom počinje genetskom mutacijom matičnih ćelija.

The stem cells themselves are not cancerous,

Matične ćelije same po sebi nisu kancerogene,

but these mutations can interfere with the process of differentiation

ali ove mutacije mogu da se umešaju u proces diferencijacije

and result in malignant blood cells.

i posledica toga su maligne krvne ćelije.

So for patients with advanced blood cancers like leukemia and lymphoma,

Stoga je za pacijente sa rakom krvi u zamakloj fazi poput leukemije i limfoma,

the best chance for a cure is often an allogeneic bone marrow transplant,

najbolje rešenje često transplantacija alogene koštane srži,

which replaces the patient’s bone marrow with a donor’s.

gde donor daje obolelom pacijentu svoju koštanu srž.

Here’s how it works.

To funkcioniše ovako.

First, blood stem cells are extracted from the donor.

Prvo se matične krvne ćelije uzmu od donora.

Most commonly,

Najčešće se matične krvne ćelije izvuku iz donorovog krvotoka

blood stem cells are filtered out of the donor’s bloodstream

by circulating the blood through a machine

tako što krv cirkuliše u mašini

that separates it into different components.

koja razdvaja krv na različite delove.

In other cases, the marrow is extracted directly

U drugim slučajevima, koštana srž se uzima iglom,

from a bone in the hip, the iliac crest, with a needle.

direktno iz koske u kuku - ilijačnog grebena.

Meanwhile, the recipient prepares for the transplant.

Primalac se u međuvremenu priprema za transplantaciju.

High doses of chemotherapy or radiation kill the patient’s existing marrow,

Jaka hemoterapija ili velike doze radijacije ubiju postojeću srž pacijenta,

destroying both malignant cells and blood stem cells.

ubijajući i maligne ćelije i matične krvne ćelije.

This also weakens the immune system,

Ovo takođe slabi imuni sistem,

making it less likely to attack the transplanted cells.

što smanjuje verovatnoću da će napasti transplantovane ćelije.

Then the donor cells are infused into the patient’s body through a central line.

Zatim se donorove ćelije ubace u telo pacijenta kroz centralnu venu.

They initially circulate in the recipient’s peripheral bloodstream,

One u početku cirkulišu u perifernom krvotoku primaoca,

but molecules on the stem cells, called chemokines, act as homing devices

ali hemokini, molekuli na matičnim ćelijama,

deluju kao uređaji za navođenje

and quickly traffic them back to the marrow.

i brzo vode krvne ćelije nazad u srž.

Over the course of a few weeks,

Tokom perioda od nekoliko nedelja

they begin to multiply and start producing new, healthy blood cells.

one počinju da se razmnožavaju i da proizvode nove, zdrave krvne ćelije.

Just a small population of blood stem cells

Samo mali broj matičnih krvnih ćelija

can regenerate a whole body’s worth of healthy marrow.

može da proizvede zdravu srž za celo telo.

A bone marrow transplant can also lead to something

Transplantacija koštane srži takođe može dovesti do nečega

called graft-versus-tumor activity,

što se naziva kalem protiv tumora efektom,

when new immune cells generated by the donated marrow

gde nove imune ćelije koje je proizvela donorova srž

can wipe out cancer cells the recipient’s original immune system couldn’t.

mogu ubiti ćelije raka koje prvobitni imuni sistem primaoca nije mogao.

This phenomenon can help eradicate stubborn blood cancers.

Ovaj fenomen može doprineti iskorenjivanju upornog raka krvi.

But bone marrow transplants also come with risks,

Međutim, transplantacije koštane srži imaju i svoje rizike,

including graft-versus-host disease.

uključujući i bolest kalem protiv domaćina.

It happens when the immune system generated by the donor cells

Do toga dolazi kada imuni sistem koji su sagradile ćelije donora

attacks the patient’s organs.

napadne pacijentove organe.

This life-threatening condition occurs in about 30–50% of patients

Ova smrtonosna bolest događa se kod oko 30 do 50 procenata pacijenata

who receive donor cells from anyone other than an identical twin,

koji prime ćelije od bilo koga ko nije njihov jednojajčani blizanac,

particularly when the stem cells are collected

posebno ako su matične ćelije uzete

from the blood as opposed to the bone marrow.

iz krvi, a ne iz koštane srži.

Patients may take immunosuppressant medications

Pacijenti mogu uzeti imunosupresivne lekove,

or certain immune cells may be removed from the donated sample

ili se određene imunoćelije mogu ukloniti iz doniranog uzorka

in order to reduce the risk of graft-versus-host disease.

kako bi se smanjio rizik od bolesti kalem protiv domaćina.

But even if a patient avoids graft-versus-host disease,

Međutim, čak iako pacijent izbegne bolest kalem protiv domaćina,

their immune system may reject the donor cells.

njegov imuni sistem može odbiti donorove ćelije.

So it’s crucial to find the best match possible in the first place.

Stoga je pre svega ključno pronaći najboljeg mogućeg donora.

Key regions of the genetic code determine how the immune system

Važni delovi genetskog koda određuju kako imuni sistem

identifies foreign cells.

identifikuje strane ćelije.

If these regions are similar in the donor and the recipient,

Ako su ti delovi slični kod donora i kod primaoca,

the recipient’s immune system is more likely to accept the donor cells.

veća je verovatnoća da će imuni sistem primaoca prihvatiti ćelije donora.

Because these genes are inherited, the best matches are often siblings.

Zato što se ovi geni nasleđuju,

najveće podudaranje će biti između braće i sestara.

But many patients who need a bone marrow transplant

Međutim, mnogi pacijenti kojima je potrebna transplantacija srži

don’t have a matched family member.

nemaju člana porodice koji bi mogao biti donor.

Those patients turn to donor registries of volunteers

Ti pacijenti se obraćaju registrima donora

willing to offer their bone marrow.

gde se mogu naći ljudi koji bi dobrovoljno dali koštanu srž.

All it takes to be on the registry is a cheek swab to test for a genetic match.

Sve što je potrebno da se nađete u registru

jeste bris usta kojim se testira genetska podudarnost.

And in many cases, the donation itself

U mnogim slučajevima samo doniranje

isn’t much more complicated than giving blood.

nije ništa komplikovanije od davanja krvi.

It’s a way to save someone’s life

To je način da spasite nečiji život

with a resource that’s completely renewable.

resursom koji je u potpunosti obnovljiv.