Experimental Human Brain Cells in Rats
by Mike James
Back in October 2022, a study was published by Stanford researchers reporting that scientists had transplanted clusters of human neurons into the brains of newborn rats. The cells even grew and formed connections. The purpose of the study was to learn about human brain development and diseases affecting the brain.
The clumps of human cells, known as "organoids," grew into millions of new neurons and wired themselves into their new rat nervous systems. Once the organoids had plugged into the brains of the rats, the animals could receive sensory signals from their whiskers and help create command signals to guide their movement.
The organoids were transplanted into rats that were two to three days old. This is the time when brain connections are forming. The organoids grew to take up a third of the rat's brain hemisphere where they were implanted. The neurons from the organoids formed working connections with circuits in the rat brain.
Dr. Sergiu Pasca, the neuroscientist who led the research, said that he and others were now using the transplanted neurons to learn about the biology of autism, schizophrenia, and other developmental disorders.
These types of experiments do raise some ethical concerns that Pasca acknowledges. Pasca and his team mentioned the rats' well-being and whether they still behave as rats with human organoids inside them. Pasca says the rats still behave like rats with the additional human matter in them. But Pasca did say it was not a good idea to try this on primates.
Giorgia Quadrato, a neurobiologist at the University of Southern California (USC), noted that the human organoids did not make the rats more human. On learning tests, the rats scored the same as other rats.
"They are rats, and they stay rats," Dr. Quadrato said. "This should be reassuring from an ethical perspective."
But what if scientists were to put human organoids into animals more like humans, like a monkey or a chimpanzee? "It would be a good opportunity to set guidelines to operate in the right ethical framework in the future," Quadrato said.
Dr. Pasca said that the similarity between primates and humans might allow the organoids to grow more and take on a bigger role in the animal's mental processes. "It's not something that we would do, or would encourage doing," he said.
Yes, maybe Dr. Pasca is not going to go there, but what about others?
Some ethicists are concerned about the possibility of these brain organoids developing human consciousness somehow as these experiments continue. Experts say this is extremely unlikely.
"You're not just worried about how many mice are in a cage, or how well they're fed," said Henry Greely, a Stanford law professor. "This is a new kind of thing. You don't know what you might see."
I find Greely's quote quite interesting. What is going on here? Are we becoming god-like as we continue to mess with the biology of different species? What would a judge of God's law say about developments in this arena? Genesis 1:21 tells us God created animals after their KIND, and it was GOOD. What happens when we start messing with that formula?
I doubt we can create a "spirit of man" (human consciousness or mind) in animals, but this type of experimentation is getting me to wonder about future Frankenstein monsters. If we are at this point now, where will we be in another 100 years?
Genesis 11:6 says, "Now nothing will be restrained from them, which they have imagined to do." When God said this, He stepped in and put a stop to the imaginations of humans. Is this a sign we may be reaching another limit?
All of this started for Pasca after training in medicine in Romania in 2009. Dr. Pasca joined Stanford as a postdoctoral researcher to learn how to create human neurons in a dish. He and his Stanford colleagues took skin cells from volunteers and bathed them in chemicals that caused them to change character. Now they were more like embryo cells, which could become any tissue in the body.
By adding more chemicals, the researchers led the cells to develop into neurons. They could then observe pulses of voltage shoot down the length of the neurons as they lay in a dish.
Dr. Pasca seems to have good intentions. He hopes that he will be able to observe differences in the way rats behave when they carry brain organoids from people with autism and other neurological conditions. Such experiments could help reveal how certain mutations alter the way the brain works.
What's that old saying? "The road to hell is paved with good intentions." Once Pandora opened the box, do you remember what happened?
Sources:
"Human Brain Cells Grow in Rats, and Feel What the Rats Feel," by Carl Zimmer, The New York Times, October 12, 2022
"Scientists Grow Human Brain Cells in Rats," Midnight Call, December 2022, p. 26.