One more reason to get a good night’s sleep | Jeff Iliff

Prevodilac: Aleksandar Kovačević Lektor: Mile Živković

Sleep.

San.

It's something we spend about a third of our lives doing,

U njemu provedemo oko trećine života,

but do any of us really understand what it's all about?

ali da li iko razume o čemu se tu zapravo radi?

Two thousand years ago, Galen,

Galen, jedan od najznačajnijih lekara

one of the most prominent medical researchers

starog veka je pre 2.000 godina

of the ancient world,

pretpostavio da se

proposed that while we're awake,

pokretačka sila našeg mozga,

our brain's motive force, its juice,

njegovo gorivo, dok smo budni

would flow out to all the other parts of the body,

sliva u ostatak tela

animating them but leaving the brain all dried up,

i oživljava ga, ali isušuje mozak,

and he thought that when we sleep,

a dok spavamo,

all this moisture that filled the rest of the body

sva ta vlaga iz ostatka tela

would come rushing back,

se vraća,

rehydrating the brain

vlaži mozak

and refreshing the mind.

i osvežava um.

Now, that sounds completely ridiculous to us now,

Sada nam to zvuči kao budalaština,

but Galen was simply trying to explain

ali to je bio Galenov pokušaj da objasni

something about sleep

jednu od odlika sna

that we all deal with every day.

sa kojom se svakodnevno susrećemo.

See, we all know based on our own experience

Svi iz iskustva znamo

that when you sleep, it clears your mind,

da san bistri um,

and when you don't sleep,

ali u nedostatku sna,

it leaves your mind murky.

on se usporava.

But while we know a great deal more about sleep now

Iako se sad zna mnogo više o snu

than when Galen was around,

nego u Galenovo vreme,

we still haven't understood why it is that sleep,

još uvek ne znamo zbog čega

of all of our activities, has this incredible

od svih aktivnosti, baš san

restorative function for the mind.

tako uspešno obnavlja um.

So today I want to tell you about

Danas ću vam pričati o nekim

some recent research

skorijim istraživanjima

that may shed new light on this question.

koje prikazuju ovo pitanje u novom svetlu.

We've found that sleep may actually be

Otkrili smo da je san

a kind of elegant design solution

možda elegantan odgovor

to some of the brain's most basic needs,

na neke od osnovnih potreba mozga,

a unique way that the brain

jedinstven način na koji mozak

meets the high demands and the narrow margins

sa malo grešaka ispunjava teške zahteve

that set it apart from all the other organs of the body.

i koji ga odvaja od ostalih organa.

So almost all the biology that we observe

Gotovo celokupna biologija

can be thought of as a series of problems

može da se posmatra kao niz problema

and their corresponding solutions,

i odgovarajućih rešenja,

and the first problem that every organ must solve

a prvi problem koji svaki organ mora da reši

is a continuous supply of nutrients to fuel

je neprekidna dostava hranljivih materija

all those cells of the body.

koje napajaju ćelije tela.

In the brain, that is especially critical;

Za mozak je to naročito važno;

its intense electrical activity uses up

njegova intenzivna električna aktivnost

a quarter of the body's entire energy supply,

troši četvrtinu energije tela,

even though the brain accounts

iako mozak čini

for only about two percent of the body's mass.

svega dva procenta telesne mase.

So the circulatory system

Zbog toga krvotok rešava

solves the nutrient delivery problem

problem dostave hranljivih materija

by sending blood vessels to supply nutrients

tako što krvnim sudovima šalje

and oxygen to every corner of our body.

hranljive materije i kiseonik u čitavo telo.

You can actually see it in this video here.

Na ovom snimku se to i vidi.

Here, we're imaging blood vessels

Prikazani su krvni sudovi

in the brain of a living mouse.

u mozgu živog miša.

The blood vessels form a complex network

Krvni sudovi čine složenu mrežu

that fills the entire brain volume.

koja prožima čitavu zapreminu mozga.

They start at the surface of the brain,

Kreću na površini mozga,

and then they dive down into the tissue itself,

a zatim se spuštaju u samo tkivo

and as they spread out, they supply nutrients

i čitavim putem u svaku ćeliju mozga

and oxygen to each and every cell in the brain.

dostavljaju hranljive materije i kiseonik.

Now, just as every cell requires

Kao što svakoj ćeliji

nutrients to fuel it,

trebaju hranljive materije,

every cell also produces waste as a byproduct,

tako i svaka proizvodi otpadne materije,

and the clearance of that waste

a čišćenje tog otpada

is the second basic problem

je drugi problem

that each organ has to solve.

koji svaki organ mora da reši.

This diagram shows the body's lymphatic system,

Ovaj dijagram prikazuje limfni sistem

which has evolved to meet this need.

koji se razvio da bi ispunio tu potrebu.

It's a second parallel network of vessels

Paralelan je u odnosu na krvotok,

that extends throughout the body.

i on prožima čitavo telo.

It takes up proteins and other waste

Sakuplja proteine i ostali otpad

from the spaces between the cells,

iz međućelijskog prostora,

it collects them, and then dumps them into the blood

a zatim ga ubacuje u krv

so they can be disposed of.

kako bi mogao da se odstrani.

But if you look really closely at this diagram,

Ako se ovaj dijagram dobro pogleda,

you'll see something

uočava se nešto

that doesn't make a lot of sense.

što nema smisla.

So if we were to zoom into this guy's head,

Ako mu uvećamo glavu,

one of the things that you would see there

između ostalog se vidi

is that there are no lymphatic vessels in the brain.

da u mozgu nema limfnih sudova.

But that doesn't make a lot of sense, does it?

Ali to baš i nema smisla, zar ne?

I mean, the brain is this intensely active organ

Mozak je ipak vrlo aktivan organ

that produces a correspondingly large amount of waste

i shodno tome proizvodi dosta otpada

that must be efficiently cleared.

koji mora da se ukloni.

And yet, it lacks lymphatic vessels, which means that

Ali ipak nema limfne sudove, što znači

the approach that the rest of the body takes

da način na koji ostatak tela

to clearing away its waste

uklanja otpad

won't work in the brain.

kod mozga ne radi.

So how, then, does the brain solve

Kako onda mozak rešava

its waste clearance problem?

problem uklanjanja otpada?

Well, that seemingly mundane question

Kod ovog naizgled običnog pitanja

is where our group first jumped into this story,

se naša grupa prvi put uključila u priču

and what we found

i pronicanjem u mozak,

as we dove down into the brain,

u neurone i krvne sudove

down among the neurons and the blood vessels,

smo otkrili

was that the brain's solution

da mozak

to the problem of waste clearance,

problem uklanjanja otpada

it was really unexpected.

rešava na neočekivan način.

It was ingenious,

Istovremeno je

but it was also beautiful.

i genijalno i prelepo.

Let me tell you about what we found.

Reći ću vam šta smo otkrili.

So the brain has this large pool

U mozgu postoji velika količina

of clean, clear fluid called cerebrospinal fluid.

čiste, prozirne tečnosti zvane moždano-moždinska tečnost.

We call it the CSF.

Zvaćemo je CSF.

The CSF fills the space that surrounds the brain,

CSF ispunjava okolinu mozga,

and wastes from inside the brain

a otpad iz unutrašnjosti mozga

make their way out to the CSF,

prelazi CSF,

which gets dumped, along with the waste, into the blood.

i sa ostalim otpadom se ubacuje u krv.

So in that way, it sounds a lot like

U tom pogledu

the lymphatic system, doesn't it?

dosta liči na limfni sistem, zar ne?

But what's interesting is that the fluid and the waste

Zanimljivo je to što tečnost

from inside the brain,

i otpad iz mozga

they don't just percolate their way randomly

ne prelaze

out to these pools of CSF.

u CSF nasumice.

Instead, there is a specialized network of plumbing

Zapravo postoji specijalizovana mreža sudova

that organizes and facilitates this process.

koja to omogućava.

You can see that in these videos.

Vidi se na ovom snimku.

Here, we're again imaging into the brain

Tu je ponovo prikazan

of living mice.

mozak živog miša.

The frame on your left shows

Sa leve strane je prikazano

what's happening at the brain's surface,

šta se dešava na površini mozga,

and the frame on your right shows

a sa desne

what's happening down below the surface of the brain

šta se dešava ispod površine,

within the tissue itself.

unutar samog tkiva.

We've labeled the blood vessels in red,

Krvni sudovi su obeleženi crvenom bojom,

and the CSF that's surrounding the brain

a CSF koji okružuje mozak

will be in green.

je zelena.

Now, what was surprising to us

Iznenadilo nas je

was that the fluid on the outside of the brain,

što tečnost koja okružuje mozak

it didn't stay on the outside.

nije ostala van njega.

Instead, the CSF was pumped back into

CSF se ustvari vraćao unutar mozga

and through the brain

i kretao se kroz njega

along the outsides of the blood vessels,

duž spoljne strane krvnih sudova,

and as it flushed down into the brain

i tokom tog kretanja

along the outsides of these vessels,

je zapravo pomagao

it was actually helping to clear away,

u čišćenju otpada

to clean the waste from the spaces

iz prostora između

between the brain's cells.

moždanih ćelija.

If you think about it,

Korišćenje spoljašnjosti

using the outsides of these blood vessels like this

krvnih sudova je

is a really clever design solution,

zapravo veoma dobro rešenje,

because the brain is enclosed

pošto je mozak okružen

in a rigid skull

čvrstom lobanjom

and it's packed full of cells,

i sasvim popunjen ćelijama,

so there is no extra space inside it

tako da u njemu nema prostora

for a whole second set of vessels like the lymphatic system.

za dodatnu mrežu sudova kao što je limfni sistem.

Yet the blood vessels,

Međutim, krvni sudovi

they extend from the surface of the brain

dosežu od površine mozga

down to reach every single cell in the brain,

do svake ćelije,

which means that fluid

što znači da tečnost

that's traveling along the outsides of these vessels

koja se kreće duž njih

can gain easy access to the entire brain's volume,

može da prodre u čitavu zapreminu mozga

so it's actually this really clever way

i to predstavlja veoma dobar način

to repurpose one set of vessels, the blood vessels,

da mreža krvnih sudova

to take over and replace the function

preuzme ulogu druge mreže,

of a second set of vessels, the lymphatic vessels,

limfnog sistema,

to make it so you don't need them.

i učini je nepotrebnom.

And what's amazing is that no other organ

Neverovatno je to da ni jedan drugi organ

takes quite this approach

ne pristupa uklanjanju otpada

to clearing away the waste from between its cells.

na ovakav način.

This is a solution that is entirely unique to the brain.

Ovo rešenje je jedinstveno za mozak.

But our most surprising finding

Ali smo se najviše iznenadili

was that all of this,

kad smo otkrili da se

everything I just told you about,

sve ovo o čemu sam pričao,

with all this fluid rushing through the brain,

tečnosti koje se kreću kroz mozak,

it's only happening in the sleeping brain.

dešava samo dok spavamo.

Here, the video on the left

Snimak sa leve strane

shows how much of the CSF is moving

prikazuje kretanje CSF

through the brain of a living mouse while it's awake.

u mozgu živog miša dok je budan.

It's almost nothing.

Skoro da ga i nema.

Yet in the same animal,

Ali ako malo sačekamo

if we wait just a little while until it's gone to sleep,

da životinja zaspi

what we see is that the CSF

vidimo kako CSF

is rushing through the brain,

teče kroz mozak,

and we discovered that at the same time

a istovremeno se vidi

when the brain goes to sleep,

da se ćelije smanjuju

the brain cells themselves seem to shrink,

dok mozak spava,

opening up spaces in between them,

čime stvaraju međućelijski prostor

allowing fluid to rush through

i omogućavaju da

and allowing waste to be cleared out.

tečnost prođe i ukloni otpad.

So it seems that Galen may actually have been

Izgleda da Galen i nije

sort of on the right track when he wrote about

mnogo pogrešio kad je pisao

fluid rushing through the brain

o tečnosti koja se kreće kroz mozak

when sleep came on.

dok spavamo.

Our own research, now it's 2,000 years later,

Naše istraživanje,

suggests that what's happening is that

2.000 godina kasnije,

when the brain is awake

pokazuje da mozak

and is at its most busy,

odlaže čišćenje otpada

it puts off clearing away the waste

iz međućelijskog prostora

from the spaces between its cells until later,

dok je budan i zauzet,

and then, when it goes to sleep

ali kad zaspi

and doesn't have to be as busy,

i ne mora više da radi,

it shifts into a kind of cleaning mode

počinje da

to clear away the waste

iz međućelijskog prostora

from the spaces between its cells,

čisti otpad

the waste that's accumulated throughout the day.

koji se nagomilao u toku dana.

So it's actually a little bit like how you or I,

Pomalo liči na to

we put off our household chores during the work week

kako odlažemo kućne poslove tokom radnih dana

when we don't have time to get to it,

jer nemamo vremena,

and then we play catch up on all the cleaning that we have to do

a onda moramo da nadoknadimo svo to čišćenje

when the weekend rolls around.

u toku vikenda.

Now, I've just talked a lot about waste clearance,

Dosta sam pričao o uklanjanju otpada,

but I haven't been very specific

ali nisam ništa određeno rekao

about the kinds of waste

o vrsti otpada

that the brain needs to be clearing

koji mozak mora da ukloni

during sleep in order to stay healthy.

tokom sna kako bi ostao zdrav.

The waste product that these recent studies

Studije su pre svega posmatrale

focused most on is amyloid-beta,

vrstu otpada zvanu amiloid-beta,

which is a protein that's made in the brain all the time.

koju čini protein kog mozak stalno proizvodi.

My brain's making amyloid-beta right now,

Moj mozak ga trenutno prozvodi,

and so is yours.

kao i vaš.

But in patients with Alzheimer's disease,

Kod obolelih od Alchajmerove bolesti

amyloid-beta builds up and aggregates

amiloid-beta se nagomilava

in the spaces between the brain's cells,

u međućelijskom prostoru mozga

instead of being cleared away like it's supposed to be,

umesto da se ukloni kao što bi trebalo,

and it's this buildup of amyloid-beta

te se smatra da je ovo nagomilavanje

that's thought to be one of the key steps

amiloid-bete jedan od ključnih koraka

in the development of that terrible disease.

u razvoju ove strašne bolesti.

So we measured how fast amyloid-beta is cleared

Izmerili smo brzinu uklanjanja amiloid-bete

from the brain when it's awake

dok smo budni

versus when it's asleep,

i dok spavamo

and we found that indeed,

i otkrili smo da je

the clearance of amyloid-beta

uklanjanje amiloid-bete zaista

is much more rapid from the sleeping brain.

mnogo brže dok spavamo.

So if sleep, then,

Ukoliko je san

is part of the brain's solution

deo načina na koji mozak

to the problem of waste clearance,

rešava uklanjanje otpada,

then this may dramatically change how we think

to bi moglo znatno da promeni način

about the relationship between sleep,

na koji gledamo odnos između sna,

amyloid-beta, and Alzheimer's disease.

amiloid-bete i Alchajmerove bolesti.

A series of recent clinical studies

Niz nedavnih studija pokazuje

suggest that among patients

da je kod pacijenata

who haven't yet developed Alzheimer's disease,

kod kojih se nije sasvim razvila Alchajmerova bolest

worsening sleep quality and sleep duration

smanjenje kvaliteta i trajanja sna

are associated with a greater amount

povezano sa povećanim nagomilavanjem

of amyloid-beta building up in the brain,

amiloid-bete u mozgu.

and while it's important to point out

Važno je napomenuti da

that these studies don't prove

iako ove studije ne dokazuju

that lack of sleep or poor sleep

da loš san ili njegov nedostatak

cause Alzheimer's disease,

izazivaju Alchajmerovu bolest,

they do suggest that the failure of the brain

ukazuju da nemogućnost mozga

to keep its house clean

da ukloni otpade

by clearing away waste like amyloid-beta

poput amiloid-bete

may contribute to the development

može da doprinese razvoju

of conditions like Alzheimer's.

bolesti kao što je Alchajmerova.

So what this new research tells us, then,

Ova istraživanja nam pokazuju

is that the one thing that all of you

da ono što svi

already knew about sleep,

znamo o snu,

that even Galen understood about sleep,

što je i Galen znao,

that it refreshes and clears the mind,

da sam osvežava i bistri um,

may actually be a big part

može biti značajan deo

of what sleep is all about.

same suštine sna.

See, you and I, we go to sleep

Svake noći

every single night,

ležemo da spavamo,

but our brains, they never rest.

ali mozak se nikad ne odmara.

While our body is still

Dok je telo nepomično,

and our mind is off walking in dreams somewhere,

a um je negde u zemlji snova,

the elegant machinery of the brain

elegantni mehanizam mozga

is quietly hard at work

neprimetno radi

cleaning and maintaining

na čišćenju i održavanju

this unimaginably complex machine.

ove nezamislivo složene mašine.

Like our housework,

Poput čišćenja kuće,

it's a dirty and a thankless job,

to je prljav i nezahvalan posao,

but it's also important.

ali i vrlo važan.

In your house, if you stop cleaning your kitchen

Ako mesec dana ne čistite kuhinju

for a month,

svoje kuće,

your home will become completely unlivable

veoma brzo u kući neće moći

very quickly.

da se živi.

But in the brain, the consequences

Što se mozga tiče, posledice

of falling behind may be much greater

nemara mogu biti mnogo ozbiljnije

than the embarrassment of dirty countertops,

od sramote zbog prljavih pultova,

because when it comes to cleaning the brain,

jer je kod čišćenja mozga

it is the very health and function

u igri samo zdravlje

of the mind and the body that's at stake,

i rad uma i tela,

which is why understanding these

i zbog toga je od ključne važnosti

very basic housekeeping functions of the brain today

za sprečavanje i lečenje budućih bolesti uma

may be critical for preventing and treating

razumevanje ovih osnovnih funkcija

diseases of the mind tomorrow.

održavanja mozga.

Thank you.

Hvala vam.

(Applause)

(Aplauz)