Boffins raise five-week-old fetal human brain in the lab for experimentation
A scientific team in Ohio has managed to raise the most complete human brain yet, and plan to use it for testing drugs and trying to understand autism.
The brain is at the same stage of development as a five-week-old fetus and contains 99 per cent of the same cells that you'd find in an in-utero equivalent. It's about the size of a pencil eraser and took 15 weeks to grow from adult skin cells.
"It not only looks like the developing brain, its diverse cell types express nearly all genes like a brain," said Rene Anand, professor of biological chemistry and pharmacology at Ohio State University.
"We've struggled for a long time trying to solve complex brain disease problems that cause tremendous pain and suffering. The power of this brain model bodes very well for human health because it gives us better and more relevant options to test and develop therapeutics other than rodents."
The brain is remarkably complete and comes with a stunted spinal cord and all major regions of the standard human noggin. It includes multiple cell types and genes, signaling circuitry, and even a retina.
It was built by taking skin cells from an adult and converting them into induced pluripotent stem cells (iPSCs) that can be reprogrammed to form almost any type of tissue. It took 15 weeks to grow the brain and the team say they're going to carry on nurturing it until it gets to the equivalent of a 12-week-old human, and maybe longer.
"If we let it go to 16 or 20 weeks, that might complete it, filling in that 1 percent of missing genes. We don't know yet," Anand said.
Ako je tacna (nedostaje jos peer review), ovo je jedna od vesti koje Naucsu na samoj granici etike.
Naucni tim iz Ohaja tvrde da su uspeli da kreiraju tj. da "uzgoje" ljudski mozak star 5 nedelja. Za ovaj poduhvat nisu koristili ljudski fetus vec kozne celije odraslih ljudi. Celije koze su procesom (za koji je dobijena Nobelova nagrada 2012-te) pretvorene u stem celije, koje su iskoriscene za formiranje "mozga".
Po recima naucnika, "mozak" koji je stvoren izgleda tako, ima oko 99% izrazenih gena, ima cak i rudimentiranu kicmenu mozdinu i retinu. Za ostalih 1% gena ce biti potrebno da se "mozak" razvije do stadijuma od 16 - 20 nedelja, za sta ce biti potrebno nesto duze vremena posto je primeceno da se ovako "mozak" razvija sporije nego u fetusu.
Impresivno, zar ne? Cak nije upotrebljen ni zivi fetus.
Osim jedne "sitnice" - kad doticni "mozak" dodje do stadijuma od 20 nedelja, postavlja se pitanje da li je to zivo bice koje ima nekakvu svest. IMHO, ako uzgojen "mozak" zaista funkcionise (fizioloski), postoji mogucnost da je svestan.
Koliko god ta rudimentirana svest bila, postavlja se eticko pitanje gde su granice.
Postoji, naravno, mnogo razloga zbog cega uzgojeni artifakt MOZDA nije zapravo "mozak" vec hrpa celija koja lici na mozak: za pocetak, te celije nisu imale stimulaciju iz okoline kakvu imaju celije mozga u fetusu. Sa druge strane, naucnici tvrde da "mozak" ima retine, sto znaci da ipak moze da dobija stimulaciju spolja.
Jedini nacin da se to proveri je da se izmeri aktivnost nervnih celija i utvrdi da li postoje organizovani ritmovi sto bi ukazivalo da nije u pitanju samo hrpa celija vec rudimentirani zacetak osobe.
Naravno, medicinske prednosti ovoga su ocigledne - mogucnost testiranja lekova, kreiranja personalizovane terapije na rudimentiranom "mozgu" pacijenta koji bi bio "uzgojen" u epruveti su neprocenjive.
Medjutim, ako rudimentirani mozak ima i tracak svesti to bi eksperimentatore cinilo izvrsiocima strahovite torture.
Mnogo pitanja koja ce morati biti odgovorena.
Jedno je sigurno - ako su rezultati ovakvi kakvi su predstavljeni, kocka je bacena i usli smo u novu fazu medicine/biologije.
Fakat da je DARPA zainteresovana ne budi bas lepe asocijacije - zamislite naoruzane dronove kojima upravljaju bioloska tkiva tj. mali mozgovi. Zvuci kao los SF... ali ko zna.
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