Researchers at the Ohio State University say they have grown a 99 percent complete human brain in a laboratory. The brain is equivalent to the maturity stage of a 5-week-old fetus.
According to the researchers, the breakthrough could speed up the pace of progress in understanding and treating neurological diseases. Lab-grown brains could be used to test new drugs and study how genes and the environment interact to shape the development of the brain and the entire central nervous system.
At a presentation at the 2015 Military Health System Research Symposium in Fort Lauderdale, Florida, on Tuesday, August 18, 2015, Rene Anand, a biochemist and member of the research team from Ohio State University in Columbus, said that the miniature lab-grown brain — about the size of a pencil eraser — has identifiable structures and expresses about 99 percent of the genes present in the human fetal brain.
The brain was grown from pluripotent stem cells derived from adult human skin cells. The pluripotent cells were induced to grow into a brain and the central nervous system.
Pluripotent cells, as the name implies, are stem cells that can be programmed to multiply and grow into practically any type of human tissue.
“Once a cell is in that pluripotent state, it can become any organ – if you know what to do to support it to become that organ. The brain has been the holy grail because of its enormous complexity compared to any other organ.”
In recent years, researchers have focused interest on using stem cells derived from the adult human skin to grow diverse human organs. But growing the human brain has proved to be challenging due to the immense complexity of the organ.
The new lab-grown brain is the most complete human brain ever grown. It represents a breakthrough because previous attempts at growing whole brains in the laboratory only achieved mini-organs or “organoids” that were not complete because they contained only certain parts of a complete brain.
But the researchers claim that this time “we have grown the entire brain from the get-go.”
“It not only looks like the developing brain, its diverse cell types express nearly all genes like a brain. 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.”
According to Anand, they were able to reproduce 99 percent of the brain’s cellular diversity, including the spinal cord, neural circuitry, and a retina.
The researchers claimed that although the brain is only equivalent to the maturity stage of a 5-week-old fetus, it can be used in research to test drugs developed to treat conditions such as autism, Alzheimer’s and Parkinson’s because the regions of the brain treated by the drugs develop early in fetal growth.
The researchers also claimed that, despite being a whole human brain, the lab-grown brain is not conscious, and thus, there are no ethical issues in using it for research.
“We don’t have any sensory stimuli entering the brain. This brain is not thinking in any way.”
The brain took about 12 weeks to grow in the laboratory. Anand said that they would need to furnish it with a cardiovascular system — a heart, veins, and arteries — to grow it beyond the maturity stage of a five-week-old fetus.
The researchers said that their next goal is to grow a brain to 16 or 20 weeks to allow for expression of the remaining one percent of genes not expressed in the five-week-old brain.
However, other researchers in the field have received the news with reservation, saying that they are unable to assess the study because the team has not published its results.
According to The Guardian, Zameel Cader, a neurologist at the John Radcliffe Hospital, Oxford, said that “When someone makes such an extraordinary claim as this, you have to be cautious until they are willing to reveal their data.”
But experts agree that if the claims prove true, it could revolutionize the way personalized medical treatment is delivered.
According to Anand, “If you have an inherited disease, for example, you could give us a sample of skin cells, we could make a brain and then ask what’s going on. We can look at the expression of every gene in the human genome at every step of the development process and see how they change with different toxins. Maybe then we’ll be able to say ‘holy cow, this one isn’t good for you.'”
Anand and his team are delaying publication of the results due to a pending patent on the technique used to grow the brain.
According to an Ohio State University press release, “Anand’s method is proprietary and he has filed an invention disclosure with the university.”
[Image: Ohio State University/Anand et al.]