Developmental Biology - Brain Organoids|
Increasingly Complex Mini Brains
Brazilian scientists produce brain organoids with a very primitive eye cell layer...
Brazilian scientists improved the initial steps of a standard protocol - to produce brain organoids that display regionalized brain structures, including retinal pigmented cells. The retina or retinal pigment epithelium (RPE) is a pigmented cell layer just outside the neurosensory retina which nourishes retinal visual cells. It is firmly attached to the underlying choroid (which contains connective tissues) and overlying retinal visual cells.
The announcement is published in BMC Developmental Biology by the D'Or Institute for Research and Education.
Human brain organoids are aggregates of reprogrammed cells. With this technique, cells extracted from skin or even urine of volunteers, are transformed into stem cells and then into neurons and other nerve cell types. These cells are cultivated for weeks, until they form into a mass that resembles an embryonic brain.
For the past few years, scientists have been trying to perfect this model in order to create organoids which are increasingly complex and similar to those in later stages of pre-natal development. Since 2016, in partnership with the Federal University of Rio de Janeiro (UFRJ), scientists from the D'Or Institute have cultivated human brain organoids in order to study neurological diseases and the effects of new drugs on the developing nervous system.
The scientists then put the nerve cells into a nutrient-rich liquid, similar to the developmental environment of the human embryo. From there, these mini-brains develop in a self-regulating manner. The team, led by Stevens Rehen PhD, recently refined the environment where cells are grown.
"These organoids demonstrate it is possible to repeat, in the laboratory, increasingly advanced gradients of human brain development. We developed a cost-effective suspension method on orbital steering plates - an alternative cultivation for brain organoids with retinal pigmented cells."
Stevens Rehen PhD, Professor, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Brazil; D’Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil; Institute of Biomedical Sciences; Federal University of Rio de Janeiro; Cidade Universitária, Rio de Janeiro, Brazil.
Organoid cultivation in suspension culture requires agitation at low shear stress to allow for nutrient diffusion, which preserves tissue structure. Multiplex systems for organoid cultivation have been proposed, but whether they meet similar shear stress parameters as the regularly used spinner flask and its correlation with the successful generation of brain organoids has not been determined.
Here we used computational fluid dynamics (CFD) to simulate two multiplex culture conditions: steering plates on an orbital shaker and the use of a previously described bioreactor. The bioreactor had low speed and high shear stress regions that may affect cell aggregate growth, depending on volume, whereas the computed variables of the steering plates were closer to those of the spinning flask.
Our protocol improves the initial steps of the standard brain organoid formation, and the produced organoids displayed regionalized brain structures, including retinal pigmented cells. Overall, we conclude that suspension culture on orbital steering plates is a cost-effective practical alternative to previously described platforms for the cultivation of brain organoids for research and multiplex testing.
Livia Goto-Silva, Nadia M. E. Ayad, Iasmin L. Herzog, Nilton P. Silva, Bernard Lamien, Helcio R. B. Orlande, Annie da Costa Souza, Sidarta Ribeiro, Michele Martins, Gilberto B. Domont, Magno Junqueira, Fernanda Tovar-Moll and Stevens K. Rehen.
NIH/National Institute of General Medical Sciences, Cure Alzheimer's Fund, Muscular Dystrophy Association, Genentech
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75 days old brain organoid stained for neurons or nerve cells (green) and astrocytes (red). Astrocytes are star-shaped glial cells of the central nervous system that surround neurons and provide support for and insulation between them. Image: D'Or Institute for Research and Education.