Human mini-brains were transplanted into rats. Is this ethical?

Julian Savulescu

channelnewsasia.com

Originally posted 22 OCT 22

Here is an excerpt:

Are 'Humanized Rats' just rats?

In a world-first, scientists have transplanted human brain cells into the brains of baby rats, offering immense possibilities to study and develop treatment for neurological and psychiatric conditions.

The human brain tissue, known as brain organoids or “mini-organs”, are independent nerve structures grown in a lab from a person’s cells, such as their skin cells, using stem cell technology. Although they can’t yet replicate a full brain, they resemble features or parts of an embryonic human brain.

The study, published in the journal Nature on Oct 12, showed that the human organoids integrated into the rat brain and function, and were even capable of affecting the behaviour of the rats.

A few months later, up to one-sixth of the rat cortex was human. In terms of their biology, they were “humanised rats”.

This is an exciting discovery for science. It will allow brain organoids to grow bigger than they have in a lab, and opens up many possibilities of understanding how early human neurons develop and form the brain, and what goes wrong in disease. It also raises the possibility of organoids being used to treat brain injury.

Indeed, the rat models showed the neuronal defects related to one rare severe disease called Timothy Syndrome, a genetic condition that affects brain development and causes severe autism.

This is one step further along the long road to making progress in brain disease, which has proved so intransigent so far.

The research must go ahead. But at the same time, it calls for new standards to be set for future research. At present, the research raises no significant new ethical issues. However, it opens the door to more elaborate or ambitious research that could raise significant ethical issues.

Moral Status of Animals with Human Tissue

The human tissue transplanted into the rats’ brains were in a region that processes sensory information such as touch and pain.

These organoids did not increase the capacities of the rats. But as larger organoids are introduced, or organoids are introduced affecting more key areas of the brain, the rat brain may acquire more advanced consciousness, including higher rational capacities or self-consciousness.

This would raise issues of how such “enhanced” rats ought to be treated. It would be important to not treat them as rats, just because they look like rats, if their brains are significantly enhanced.

This requires discussion and boundaries set around what kinds of organoids can be implanted and what key sites would be targets for enhancement of capacities that matter to moral status.

The info is here.

This company is about to grow new organs in a person for the first time

Jessica Hamzelou

MIT Technology Review

Originally posted 25 AUG 22

Here is an excerpt:

Livers have a unique ability to regenerate. Cut away half an animal’s liver, and it will grow back. Human livers damaged by toxins or alcohol can usually regrow too. But some diseases can cause extensive damage from which the liver can’t recover. For these diseases, the treatment of choice is usually a liver transplant.

Transplants aren’t always an option for people who are very unwell, however. That’s why Eric Lagasse and his colleagues at LyGenesis have taken this different approach. Lagasse, a stem-cell biologist at the University of Pittsburgh, has spent years researching cell-based treatments for liver disease. Around 10 years ago, he was experimenting with the idea of injecting cells from healthy livers into diseased ones in mice.

It is difficult to access the livers of small, 25-gram mice, which Lagasse was studying, so instead he and his colleagues injected the cells into the spleens of mice with liver disease. They found that the cells were able to migrate from the spleen to the liver. To find out if they could migrate from other organs, Lagasse’s team injected liver cells at various sites in the mice’s bodies.

Only a small number of mice survived. When Lagasse and his colleagues later performed autopsies on those survivors, “I was very surprised,” he recalls. “We had a mini liver present … where the lymph node would be.”

Little incubators

Lymph nodes are small, bean-shaped structures found throughout the body. They play a crucial role in our immune health, making cells that help fight infections. And while Lagasse was initially surprised that liver cells could multiply and grow in lymph nodes, it makes sense, he says. 

Lymph nodes are natural homes for rapidly dividing cells, even if those are usually immune cells. Lymph nodes also have a good blood supply, which can aid the growth of new tissue.

The info is here.

Breakthrough as scientists grow sheep embryos containing human cells

Nicola Davis
The Guardian
Originally published February 17, 2018

Growing human organs inside other animals has taken another step away from science-fiction, with researchers announcing they have grown sheep embryos containing human cells.

Scientists say growing human organs inside animals could not only increase supply, but also offer the possibility of genetically tailoring the organs to be compatible with the immune system of the patient receiving them, by using the patient’s own cells in the procedure, removing the possibility of rejection.

According to NHS Blood and Transplant, almost 460 people died in 2016 waiting for organs, while those who do receive transplants sometimes see organs rejected.

“Even today the best matched organs, except if they come from identical twins, don’t last very long because with time the immune system continuously is attacking them,” said Dr Pablo Ross from the University of California, Davis, who is part of the team working towards growing human organs in other species.

Ross added that if it does become possible to grow human organs inside other species, it might be that organ transplants become a possibility beyond critical conditions.

The information is here.

No Pain, All Gain: The Case for Farming Organs in Brainless Humans

Ruth Stirton and David Lawrence
BMJ Blogs
Originally posted June 10, 2017

Here is an excerpt:

A significant challenge to this practice is that it is probably unethical to use an animal in this way for the benefit of humans. Pigs in particular have a relatively high level of sentience and consciousness, which should not be dismissed lightly.  Some would argue that animals with certain levels of sentience and consciousness – perhaps those capable of understanding what is happening to them – have moral worth and are entitled to respect and protection, and to be treated with dignity.  It is inappropriate to simply use them for the benefit of humanity.  Arguably, the level of protection ought to correlate to the level of understanding (or personhood), and thus the pig deserves a greater level of protection than the sea cucumber.  The problem here is that the sea cucumber is not sufficiently similar to the human to be of use to us when we’re thinking about organs for transplantation purposes.  The useful animals are those closest to us, which are by definition those animals with more complex brains and neural networks, and which consequently attract higher moral value.

The moral objection to using animals in this way arises because of their levels of cognition.  This moral objection would disappear if we could prevent the animals ever developing the capacity for consciousness: they would never become entities capable of being harmed.  If we were able to genetically engineer a brainless pig, leaving only the minimal neural circuits necessary to maintain heart and lung function,  it could act as organic vessel for growing organs for transplantation.  The objection based on the use of a conscious animal disappears, since this entity – it’s not clear the extent to which is it possible to call it an animal – would have no consciousness.

The blog post is here.