Study Reveals Long-Term Aging In Brain Organoids

Scientists have grown human brain cells, known as organoids, for a record seven years in a laboratory, revealing that these clusters of cells age in a manner similar to those found in the human body. Organoids are cultivated from stem cells and are utilized by researchers globally to investigate brain development and test medications without employing animal models such as mice.

The typical lifespan of an organoid is only a few months, restricting its ability to showcase later stages of brain development. The human brain, however, requires approximately 20 years to mature fully. The research team, led by Paola Arlotta of Harvard University, managed to sustain organoids for around seven years, making them the oldest organoids ever grown.

Arlotta, a senior author of the study published in Nature, stated that the findings demonstrate the brain's capability to advance outside the human body for an unprecedented duration. The organoids "recorded the passage of time and retain a memory of the developmental steps already performed," although they do not possess human-style memories.

Instead, their prior development is preserved at a cellular level. The scientists utilized three recent genetic clocks to measure the biological age of the cells within the organoids, confirming that the organoids underwent alterations over time akin to regular brain cells. To validate their results, the researchers conducted an experiment where they combined cells that had been developing for a year with cells only two weeks old, creating a chimeric organism.

While the younger cells functioned as expected, the more mature cells advanced in development, beginning to generate neurons that typically take about four months to form. This experiment effectively "warped time" for brain development and could potentially expedite the study of certain brain cells in the future. The previous record for the oldest brain organoids was slightly under two years.

The lab-grown organoids, unlike human brains, lack a body that can become ill or die. It remains uncertain whether these organoids could potentially outlive humans, though Arlotta suspects they may live slightly longer. The organoids used in the new study have since been destroyed.