Overview
- The study published in Nature reports that human brain organoids were maintained in culture for years, with molecular analyses through five years and press reporting noting some samples reached about seven years.
- Over time the organoids showed progressive gene-expression programs and cell-type changes that match first- and second-trimester fetal stages and newborn brain patterns, including signs of myelination and other cellular ageing.
- When researchers mixed cells from older organoids with younger cells, the older cells produced neuron types appropriate to their prior age, indicating a cell-intrinsic molecular 'memory' of developmental time.
- Independent analyses found a major limitation: organoids show skewed timing of progenitor behavior and altered fate choices, a problem researchers attribute to missing in vivo inputs such as blood vessels, extracellular matrix complexity and metabolic signals.
- Scientists say long-lived organoids could help model disorders like autism and schizophrenia but caution that the tissues are simplified, lack sensory input or evidence of consciousness, and that the experimental organoids used in the study have been destroyed.