SoylentNews

"exec" writes:

Arthur T Knackerbracket has found the following story:

As research involving the transplantation of human "mini-brains" -- known as brain organoids -- into animals to study disease continues to expand, so do the ethical debates around the practice. One concern is the possibility, however minute, that the grafted organoids may one day induce a level of consciousness in host animals, as models evolve to resemble the human brain more closely.

A new paper published today in Cell Stem Cell by researchers from Penn Medicine and the Department of Veterans Affairs sought to address this dilemma by clarifying the abilities of brain organoids and suggesting an ethical framework that better defines and contextualizes these organoids and establishes thresholds for their use. Their paper accompanies another study in the same journal that reported the presence of brain wave patterns, known as oscillatory activity, in brain organoids, which brought fresh attention to the overall research and ethical discussion.

"Due to their ability to mimic certain brain structures and activity, human brain organoids -- in animal models -- allow us to study neurological diseases and other disorders in previously unimaginable ways," said the study's first author H. Isaac Chen, MD, an assistant professor of Neurosurgery at Penn's Perelman School of Medicine and the Corporal Michael J. Crescenz VA Medical Center. "However, the field is developing quickly, and as we continue down this path, researchers need to contribute to the creation of ethical guidelines grounded in scientific principles that define how to approach their use before and after transplantation in animals. Such guidelines can help avoid confusion for scientists, especially when communicating with the public, and clearly lay out the benefits of this research, against which any ethical or moral risks can be weighed."

Lab-grown brain organoids -- which are derived from human pluripotent stem cells and grown to a size no bigger than a pea -- can recapitulate important brain architecture and several basic layers of the human cortex. Some resemble the midbrain, hippocampus, and the hypothalamus, and have genetic similarities to the human brain. There is also preliminary evidence suggesting that neurons within transplanted organoids respond to light stimulation of the host animal's eye, results which were presented in a Penn Medicine abstract at the Society for Neuroscience meeting in November 2017.

Still, today's brain organoids remain distinctly different from the actual human brain, the authors note. Their maximum size remains small (measured in millimeters) due to inadequate nutrient, gas, and waste exchange which limits development. Organoids also lack endothelial cells, microglia cells (key cells in overall brain maintenance), and other cell types that contribute to the brain's microenvironment. Furthermore, organized structural nodes and the white matter connections among these cells are absent -- which are both necessary for higher brain function.

Work on developing a "better" brain organoid, however, continues to make strides. And with that, the question of the host animal becoming more "human" remains at the forefront of the ethical debate. One particular outcome that has raised concerns is the potential appearance of self-awareness and consciousness in the animals, but authors note that this is unlikely for several reasons.

Journal Reference:
H. Isaac Chen, John A. Wolf, Rachel Blue, Mingyan Maggie Song, Jonathan D. Moreno, Guo-li Ming, Hongjun Song. Transplantation of Human Brain Organoids: Revisiting the Science and Ethics of Brain Chimeras. Cell Stem Cell, 2019; 25 (4): 462 DOI: 10.1016/j.stem.2019.09.002

-- submitted from IRC

Original Submission