In labs all throughout the world, tiny, immature replicas of various organs, such as bladders, pancreases, and brains, are being grown in Petri dishes.
These collections of human cells, known as organoids, may sound like something from of science fiction classic “Brave New World” by Aldous Huxley, but they are already assisting researchers in their quest to better understand disease.
The most recent development occurred on Wednesday when an international team of researchers published their successful attempts to implant human brain organoids into the brains of newborn rats in the journal Nature.
Organoids will develop like the rats do, enabling researchers to study complicated psychiatric conditions like schizophrenia and autism. These organoids are being used in laboratories all around the world at various phases of research.
Thousands of brain organoids have been developed at the molecular processes of pathological and physiological ageing laboratory at the Pasteur Institute in France since late 2020. Hundreds of these small white balls are being kept in the lab at a temperature of 37 degrees Celsius (98 degrees Fahrenheit), and a machine keeps them moving constantly to circulate nutrients and prevent them from clumping.
Through the third dimension
So, how did they develop?
In the natural world, a collection of stem cells develops when sperm and eggs are fertilised. These stem cells, also known as “pluripotent,” can differentiate into every type of human body cell, including brain and skin cells.
Shinya Yamanaka, a Japanese scientist, discovered a method to take adult cells and reprogram them to return to their original pluripotent state, which allows them to once more become any type of cell, about 20 years ago.
These Induced Pluripotent Stem Cells (iPS) may be created in a laboratory, and it is believed that using them would help to resolve some of the controversy surrounding the use of human embryonic stem cells.
Yamanaka received the 2012 Medicine Nobel Prize for his work, which is expected to have a major impact on the field of human biology.
In just a few months, the Pasteur Institute’s lab was able to develop brain organoids from iPS cells to a size of three to four millimetres.
The organoids are “far simpler than the human cerebral cortex,” according to Miria Ricchetti, the laboratory’s director.
According to the researcher, “These organoids are formed of many cell types that interact with each other, generating layers that position themselves correctly when compared to a normal brain.”
The organoids now possess a three-dimensional structure that is quite comparable to a developing human brain at roughly 20 weeks old.
This is one of the exhilarating aspects of this developing industry. Organoids allow researchers to stretch into the third dimension while most current study is done on two-dimensional cells.
According to Ricchetti, “certain medications will work on 2D cells before we discover that they don’t work on 3D cells.
Organoids are expected to offer a novel approach to understanding the many stages of a disease and to testing new medications. For instance, they could be used to determine whether a medicine is harmful and how its molecules work.
Additionally, it might indicate that fewer animal tests of this nature are necessary.
According to Juergen Knoblich, a molecular biologist at the Institute for Molecular Biotechnology in Austria, many brain research that are now conducted on mice or rats “should be done on primates,” but he added that this is “extremely controversial.”
He told the Science Media Centre that “Organoid models from human stem cells are promising and address this problem.”
The development of a brain with Cockayne syndrome, a rare and fatal degenerative disease, is being studied by Ricchetti’s team utilising its organoids.
Some of the specimens from the Pasteur Institute will venture into uncharted territory next year.
The International Space Station will receive some of the organoids to study the molecular effects of space travel on human brain cells.