Creation of miniature, brain-like clusters of human cells could replace animal models and more reliably establish safe, effective drugs
Researchers at the Johns Hopkins Bloomberg School of Public Health created the structures using induced pluripotent stem cells (iPSCs), which are derived from adult cells in contrast to embryonic varieties. They first converted human skin cells into iPSCS, and then formed brain cells from this new population.
"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. While rodent models have been useful, we are not 150-pound rats. And even though we are not balls of cells either, you can often get much better information from these balls of cells than from rodents"
The resulting brain-like are only 350 micrometres in diameter and are just visible to the human eye. While they may be small, many hundreds of copies can be created at the same time and around 100 can fit within one petri dish. The 'mini-brains' contain 4 types of neurons in addition to astrocytes and oligodendrocytes which support neuronal activity with a range of functions. Oligodendrocytes in particular are able to create myelin, which insulates axons and enables fast communication within the nervous system.
"We don't have the first brain model nor are we claiming to have the best one. 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"
The team was able to confirm activity by measuring signals through an electroencephalogram, also known as an EEG, This enables researchers to monitor electrical activity within the structures in response to drugs for example, allowing them to ascertain drug efficacy or even study the effects of a specific mutant gene.
Are mini-brains an improvement on current methods?
Animal testing is frequently inaccurate, and many drugs fail when tested on humans. With no real alternative however, they've still been essential to progress, but many scientists are searching for superior (and perhaps more ethical) ways of testing in the lab. Using human cells to form primitive organs is one such alternative, and these 'mini-brains' could well revolutionise neurological medical research. The structures may only equal a foetal brain at around 2 months, but they can still provide a great deal of information when it comes to modelling diseases like Parkinson's for example.
Read more at The Guardian