From New Scientist

Almost fully-formed brain grown in a lab.
Woah: Scientists grow first nearly fully-formed human brain.
Boffins raise five-week-old fetal human brain in the lab for experimentation.

On Tuesday, all the above appeared as headlines for one particular story.

What was it all about?

Mini-brains 3 to 4 millimetres across have been grown in the lab before, but if a larger brain had been created – and the press release publicising the claim said it was the size of a pencil eraser – that would be a major breakthrough. New Scientist investigated the claims.

The announcement was made by Rene Anand, a neuroscientist at Ohio State University in Columbus, at a military health research meeting in Florida.

Anand says he has grown a brain – complete with a cortex, midbrain and brainstem – in a dish, comparable in maturity to that of a fetus aged 5 weeks. Anand and his colleague Susan McKay started with human skin cells, which they turned into induced pluripotent stem cells (iPSCs) using a tried-and-tested method. By applying an undisclosed technique, one that a patent has been applied for, the pair say they were able to encourage these stem cells to form a brain.

“We are replicating normal development,” says Anand. He says they hope to be able to create miniature models of brains experiencing a range of diseases, such as Parkinson’s and Alzheimer’s.
Inconclusive evidence

But not everyone is convinced, especially as Anand hasn’t published his results. Scientists we sent Anand’s poster presentation to said that although the team has indeed grown some kind of miniature collection of cells, or “organoid”, in a dish, the structure isn’t much like a fetal brain.

Jürgen Knoblich of the Institute of Molecular Biotechnology in Vienna, Austria, grew a similar brain-like structure in 2013, albeit without a midbrain. He says that Anand hasn’t presented enough evidence to show that his organoid really has all the typical parts of a brain.

The only way the team can be sure they have grown the equivalent of a fetal brain would be to genetically test individual cells from different regions of the organoid, and compare them to those of human fetus, says Christof Koch at the Allen Institute for Brain Science in Seattle. “There is no evidence that [Anand] has done this.”

Anand says he performed a genetic analysis of the brain-like structure as a whole, and that he found 99 per cent of the genes known to be expressed in the human brain. But he hasn’t analysed the different parts of the brain on their own.

“The fact that a [cell] culture expresses most genes present in the brain says nothing about its appropriateness as a disease model,” says Knoblich. “Without using markers for different brain regions, the claim that he has achieved a 3D model of the brain is entirely unjustified.”
Under the radar

“I do not see any full development of major parts of the brain,” agrees Elena Cattaneo, who directs the Centre for Stem Cell Research at the University of Milan in Italy.

Anand says that he wasn’t able to test separate regions of the mini-brain. It was too small to slice up, he says. Cattaneo disagrees. “The structure is quite big,” she says, big enough to test individual slices.

Koch adds that there is no evidence that the cells are connected like the neurons in our brains. “They are a bunch of cells in a dish, like a soup,” he says.

Anand disputes this, and says he has early results suggesting that electrical activity can spread through the organoid in the same way it would through a human brain.

Researchers are also riled that none of Anand’s work on this project has been subject to peer review. Anand told New Scientist that while he does respect the peer review process, he is confident enough of his results to start publicising them, with the aim of attracting potential collaborators.

“It would have helped Anand’s case if he had followed standard scientific procedures and published these findings instead of seeking to immediately monetise them,” says Koch.

IMAGE: Brain of contention (Image: Ohio State University)

For more on this story go to: https://www.newscientist.com/article/dn28075-scientists-reject-claims-of-lab-grown-mini-human-brain/