Scientists Create World’s Oldest Lab-Grown Human Brains
A group of researchers has successfully developed organoids that are now recognized as the oldest lab-grown human brains, with some cells having thrived for approximately seven years.
These tiny cell clusters, about the size of a peppercorn, were cultivated by scientists at Harvard over a span of more than five years, breaking the previous record of 694 days. This milestone was detailed in a recent article published in Nature.
Paola Arlotta, the leading author of the study, noted that some cells indeed grew for around seven years and displayed characteristics akin to those found in actual human brains, as reported by Agence France Presse (AFP).
The research suggests that “the data indicate that human brain organoids record the passage of time following endogenous milestones and employing similar epigenetic mechanisms,” the study highlights.
In her words, the work illustrates that a diversity of cells within organoids can develop over extended periods and can effectively document and remember their developmental age.
Organoids are essentially three-dimensional clusters of cells that replicate the structure and functionality of human organs. They serve as valuable tools for scientists in drug testing, disease modeling, and studying human development.
Typically, these cell assemblies tend to perish within two years due to a lack of oxygen and the absence of a vascular system since they grow outside the human body. Interestingly, it takes nearly 20 years for the human brain to complete its development.
The Harvard researchers conducted observations on 34 organoids at different stages, ranging from six months to five years, and noted remarkable similarities in the development of their artificial cells compared to human brain cells.
Using a technique known as DNA methylation profiling—a chemical process that occurs during development—researchers added tags to DNA molecules, which has proven useful for determining cell age. Arlotta referred to this method as a reliable “age clock.”
According to her, the methylation clock demonstrated that these organoids were essentially performing processes characteristic of a natural brain.
The team also experimented by mixing cells from a one-year-old artificial brain with cells that were just two weeks old. Arlotta observed that the younger cells behaved normally while the older ones “jumped ahead a whole chunk of development.”
Notably, the cells were able to produce neurons, a process that normally takes around four months. This effectively “warped time” concerning brain development, which Arlotta described as a “super cool” undertaking.
Although the brain organoids have since been destroyed, there’s a suggestion that the cells could potentially endure for an even longer duration. “Nobody really knows,” Arlotta admitted when discussing the possible lifespan.
Neuroscientist Guo-li Ming referred to this achievement as a “technology breakthrough,” as reported by NPR. Various scientists in the U.S. have been using organoids to study Alzheimer’s disease, the sixth-leading cause of death in the country.
The cells allow researchers to model the progression of the disease by monitoring aspects like amyloid-beta and tau plaque formations, which ultimately lead to the death of brain cells. Arlotta expressed hope that the recent findings might also shed light on the progression of diseases such as schizophrenia.
