Human brain organoid transplanted into a rat brain

Decades of research have shown that it is feasible to transplant individual human and rodent neurons into rodent brains, and more recently, it has been shown that human brain organoids (arrays of brain cells resembling “mini-brains”) can be integrated into rodent brains. Developing. However, whether these organoid grafts can be functionally integrated with the visual system of injured adult brains has not been explored until now.

Successfully transplanting individual brain cells is not the same as transplanting an entire mass of brain tissue. The latter is much more difficult.

The team of Dr. H. Isaac Chen, professor of neurosurgery at the University of Pennsylvania, in the United States, grew neurons derived from human stem cells in the laboratory for about 80 days, allowing cell proliferation to give rise to brain organoids.

Once this stage was reached, the team grafted them into the brains of adult rats that had suffered damage to the visual cerebral cortex.

Within three months of transplantation, the implanted organoids had integrated into their host’s brain: they became vascularized, grew in size and number, sent out neural projections, and formed synapses with rat neurons.

The brain of a rat grafted with a human brain organoid. (Photo: Jgamadze et al. CC BY SA)

Chen and his colleagues report the technical details of these experiments in the academic journal Cell Stem Cell, under the title “Structural and functional integration of human forebrain organoids with the injured adult rat visual system.” (Fountain: NCYT by Amazings)