Johns Hopkins scientists create 'mini-brains' for neurodegeneration researchers

One of the challenges in studying the human brain is its sheer complexity compared with the brains of laboratory mice and rats. Now, researchers say they have created "mini-brains"--balls of cells derived from human cells--to create a new system that may lead to more reliable brain research and drug testing.

Thomas Hartung directs the new research from the Johns Hopkins Bloomberg School of Public Health, along with his team, who presented their work this month at the annual meeting of the American Association for the Advancement of Science.

The researchers hope this system will give other scientists the opportunity to advance our understanding of the human brain, including neurodegenerative diseases like Alzheimer's and Parkinson's. A significant number of drugs may show promise in smaller animals but fail to work in human clinical trials, and this tech may help accelerate drug development for better drugs targeting the brain.

"Ninety-five percent of drugs that look promising when tested in animal models fail once they are tested in humans at great expense of time and money," said Hartung. "We believe that the future of brain research will include less reliance on animals, more reliance on human, cell-based models."

The team created these human-like mini-brains by forcing healthy adult cells back into embryonic-like stem cells called induced pluripotent stem cells (iPSCs). From these human iPSCs, it is possible to generate all types of human cells, including a mix of brain cells.

After growing the cells in a petri dish for about two months, the researchers generated four types of neurons and two types of support cells--astrocytes and oligodendrocytes--the latter important for insulating neurons to help them signal faster. They then demonstrated electrophysiological activity that resembles the behavior of adult neurons by placing an array of electrodes around the mini-brain, showing promise as it responded to test drugs.

Hartung understands the limitations of their mini-brains but places importance on a reproducible system. "We don't have the first brain model nor are we claiming to have the best one," he says. "But this is the most standardized one. And when testing drugs, it is imperative that the cells being studied are as similar as possible to ensure the most comparable and accurate results."

Hartung is meanwhile applying for a patent for their mini-brains and has also started a company called Organome to produce them, which he hopes will kick off this year.

- here's the release