Scientists have successfully implanted tiny human brains in mice

Scientists from Salk University (USA) have reported a breakthrough in working with brain organelles, whose lifespan has now become almost unlimited. They managed to solve the problems of supplying cells with oxygen and nutrients throughout the entire volume of the organoid, without the death of individual areas. To do this, the researchers implanted human brains in laboratory mice, and they successfully took root there.

Brain organelles are artificial structures grown from stem cells that mimic the human brain in miniature. They were first created back in 2013, and today scientists can grow a wide variety of organelles in order to study pathologies, developmental anomalies, the consequences of trauma and the effects on the brain of various factors. An important problem was the provision of their vital functions - even in a special nutrient medium, organelles survived no longer than 5 weeks.

Experts from Salk University decided to use a ready-made life support system for the brain of laboratory mice, for which they cut out a fragment the size of a lentil grain and replaced it with an organoid, covering the incision site with a transparent window. Approximately 80% of all implants have successfully taken root, and after the 12th week they even began to grow completely new neurons, adapting to the environment. The life record for human organelles in a mouse brain was 233 days!

As soon as the organelles' survival rate became apparent, a bioethical question immediately arose: did we create a human mouse? How will a creature with a part of the brain of a different, highly developed species behave? Answer: no way, the mice remained mice and on all tests showed the same results as their non-operated relatives. Rodents perform only the function of an incubator, a living factory for growing organelles - a new species of creature cannot be obtained in this way.