Stem cell research has allowed medicine to go places that were once science
fiction. Using stem cells, scientists have manufactured heart cells, brain
cells and other cell types that they are now transplanting into patients as
a form of cell therapy. Eventually, the field anticipates the same will be
possible with organs. A new paper written by a group of international
researchers led by Tsutomu Sawai, an assistant professor at the Kyoto
University Institute for the Advanced Study of Human Biology (ASHBi) and the
Center for iPS Cell Research and Application (CiRA), explains the future
ethical implications of this research with regards to brain organoids, a
laboratory-made structure that is designed to grow and behave like the
brain.
In just over ten years, a new word has entered the lexicon of stem cell
science. “Organoids” describe organ-like structures that imitate how organs
form in the body. By recapitulating normal development, organoids have
proven to be invaluable tools for understanding not only how organs grow,
but also how diseases develop. Organoids have been reported for an
assortment of organs, including the liver, kidney and, most controversially,
the brain, along with others.
The brain is considered the source of our consciousness. Therefore, if brain
organoids do truly mimic the brain, they too should develop consciousness,
which, as the paper states, brings all sorts of moral implications.
“Consciousness is a very difficult property to define. We do not have very
good experimental techniques that confirm consciousness. But even if we
cannot prove consciousness, we should set guidelines, because scientific
advancements demand it,” said Sawai, who has spent several years writing
about the ethics of brain organoid research.
Brain organoids have led to deep questions about consciousness. With some
people imagining a future where our brains are uploaded and kept on the
cloud well after our bodies die, organoids bring an opportunity to test
consciousness and morality in artificial environments.
Ethicists have broken consciousness down into many types. Phenomenal
consciousness assumes the awareness of pain, pleasure and distress. Sawai
and his colleagues argue that even though restraints on experiments using
brain organoids would be needed, phenomenal consciousness would not outright
prohibit experiments, since animals commonly used in science, such as
rodents and monkeys, also display phenomenal consciousness.
Self-consciousness would add to the ethical conflicts, since this status
bestows a higher morality.
However, Sawai said there is a more pressing issue.
“One of the biggest problems is transplants. Should we put brain organoids
into animals to observe how the brain behaves?”
Stem cell research has presented the possibility of growing xeno-organs. For
example, researchers have had profound success at growing mouse pancreas in
rat and vice versa, and similar research is expected to lead to human
pancreas being grown in pigs. In principle, these animals would become organ
farms that can be harvested and circumvent the long wait time for organ
donors.
While growing whole human brains inside animals is not under any serious
consideration, transplanting brain organoids could give crucial insight on
how diseases like dementia or schizophrenia form and treatments to cure
them.
“This is still too futuristic, but that does not mean we should wait to
decide on ethical guidelines. The concern is not so much a biological
humanization of the animal, which can happen with any organoid, but a moral
humanization, which is exclusive to the brain,” said Sawai.
Other concerns, he added, include enhanced abilities – think Planet of the
Apes. Furthermore, if the animal developed humanized traits, then treating
it sub-humanely would violate human dignity, a core tenet of ethical
practice.
The paper notes that some people do not consider these outcomes unethical.
Enhanced abilities without a change in self-consciousness is equivalent to
using a higher animal in experiments, like shifting from mouse to monkey.
And a change in dignity does not mean a change to human dignity. Instead,
the change could result in a new type of dignity.
Regardless, the authors believe that the possibility of unintended
connections between the transplanted brain organoid to the animal brain
deserves precautionary consideration.
The biggest concern regarding brain organoid transplantation, however, does
not involve animals. There is good reason to believe that as research
proceeds, the future will bring the possibility of transplanting these
structures into patients who suffered from sudden trauma, stroke or other
injury to the brain.
There are already a number of clinical trials that involve the
transplantation of brain cells as a cell therapy in patients with such
injury or neurodegenerative diseases. Sawai said that the ethics behind
these therapies could act as a paradigm for brain organoids.
“Cell transplantations change the way brain cells function. If something
goes wrong, we can’t just take them out and start over. But right now, cell
transplantation is usually in just one location. Brain organoids would be
expected to interact more deeply with the brain, risking more unexpected
changes,” he believes.
In the end of 2018, the stem cell field was in uproar when a scientist
announced that he had genetically engineered a human embryo that went to
term. The actions of the scientist were in clear violation of international
frameworks and resulted in his prison sentence.
To avoid a similar controversy and possible loss of public confidence in
brain organoid research, the paper states explicitly that all stakeholders,
including ethicists, policy-makers and scientists need to remain in constant
communication about progress in this field.
“We need to regularly communicate with each other on scientific facts and
their ethical, legal and social implications,” said Sawai.
Reference:
Sawai T, Hayashi Y, Niikawa T, et al. Mapping the ethical issues of brain
organoid research and application. AJOB Neurosci. 2021;0(0):1-14.