The Brave New World of Organoids

One of the big scientific news stories of 2019 involved the use of organoids to help fight disease, and to learn more about how embryos build entire human beings from one fertilized egg cell. The term organoids has a science fictiony sound to it. A title like “Attack of the organoids” wouldn’t be out of place in an SF library. Actually, the ability to create specialized tissue—like bundles of brain neurons that hook together to transmit nerve impulses—can raise a few hairs on one’s neck. But organoids do hold great promise for curing diseases, broadening our understanding of development, and personalizing medical treatments.

Stem cells allow scientists to build organoids. Stem cells are like major subcontractors produced by embryos to build the various organs and organ systems we depend on. These pluripotent cells (cells that can differentiate in many ways) can produce brain, kidney, lung, intestinal, stomach, and liver tissue. The tissue clumps produced tend to be small—roughly the size of a pea—partly because they don’t have access to the circulatory system the body uses to provide oxygen and nutrients and remove wastes. Scientists have to provide work-arounds to keep organoids alive and functioning.

One of the amazing things about organoids is that they self-organize into recognizable tissues without input from an entire body. Take brain cells for example. The neurons produced by stem cells link up and form networks that are capable of transmitting nerve impulses like an intact, complete brain. One leading researcher in this field of study is Alysson Muotri, a biologist at University of California San Diego School of Medicine. His website is www.medschool.ucsd.edu. He also has a fascinating series of YouTube videos called “Building The Brain With Alysson Muotri.“ Muotri was senior author on a paper in 2019 in Cell Stem Cell. His lab was able to nurture the growth of brain organoids for many months. After four months electrical activity in the organoids began to increase exponentially. By twenty-five weeks, a computer program had a hard time distinguishing between brain wave patterns produced by organoids and pre-term babies.

Brain tissue organoids also hold promise for studying conditions like autism in human beings—a kind of neurological condition marked by differences in learning styles, repetitive motions, and sometimes difficulty with language and communication. The Harvard Stem Cell Institute is also studying how the Zika virus associates with microcephaly (small brain syndrome) during early embryo development.

Someday, scientists may be able to routinely take stem cells from individuals and test the efficacy of drugs on that person’s liver cells, for example, to make sure those drugs won’t produce harmful or fatal effects.

The brave new world of organoids is coming—and not just in the next SF novel you read.

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