Millennial Chimeras

Image Source: Tribe.

More news from back at the lab: the mythological chimera is coming alive in Millennial medical and genetic experiments. In the Greek myths, the original chimera we know dated from around 350 BCE; it was a female creature with the combined anatomy of a lion, snake and goat (see it here). 'Chimera' used in the modern cultural sense (as here, in a recent post at Ghost Hunting Theories) has come to mean any multi-part monster or hybridized fantastic creature. Often, these creatures' liminal nature and extraordinary anatomy and abilities saw them associated in ancient times with spirits, religions, deities or divine power.

The growing scientific capacity of our society so disturbs the popular imagination that some Millennial conspiracy theorists speculate that the chimeras in Greek mythology were in fact genetic chimeras created by ancient alien scientists. In this way, they reenforce an imaginative continuity with the cultural context of the deep past; and they do this at the very point where today's findings are placing that connection with the past under its greatest moment of stress.

Recent mentions of chimeras or quasi-chimeras include:

• 1997: The Vacanti Earmouse
• August 2003: Rabbit-human fusion - "Researchers at the Shanghai Second Medical University in China reported that they had successfully fused human skin cells and dead rabbit eggs to create the first human chimeric embryos."
• January 2004: Pigs with human blood - pig-human chimera cells surprise researchers: "Pigs grown from fetuses into which human stem cells were injected have surprised scientists by having cells in which the DNA from the two species is mixed at the most intimate level. It is the first time such fused cells have been seen in living creatures. ... The adult pigs that had received human stem cells as fetuses were found to have pig cells, human cells and the hybrid cells in their blood and organs."
• April 2005: Cat-human hybrid proteins - "Allergic to cats? Then you’ll appreciate this experiment. The feline Fel d 1 protein found in cat saliva contains an allergen that affects humans. When cats lick themselves, the saliva on their fur dries and turns into dust. In April 2005, scientists at the University of California created a human-cat hybrid when they fused the Fel d 1 protein with a human protein known to suppress allergic reactions. The feline protein would bind to immune cells that would cause the reaction and the human protein would tell the immune cells to calm down. When tested in mice, the chimeric protein stifled the allergy, and researchers hope they can be used in the future to treat allergy sufferers."
• 2005-present: Mouse-human brain - "Irving Weissman, Stanford University professor and cofounder of the biotech company StemCells Inc., was granted permission by Stanford to create a mouse-human hybrid in 2005. Weissman and his team transplanted human-brain stem cells into the brains of mice with the intention to study neurodegenerative diseases such as Parkinson's and Alzheimer's. In his initial experiment, the human cells only made up less than 1 percent of the mouse brain. ... In 2010, Stanford researchers announced they transformed mouse skin cells into fully functional neurons in a laboratory dish for the first time. They also announced in May [2012] that they successfully used mouse stem cells to develop sensory hair cells, which could combat human hearing loss."
• 2007: Sheep with human livers - "scientists at the University of Nevada School of Medicine created a sheep whose blood contained 15% human cells and 85% sheep cells." From Discovery News: " In 2007, scientists at the University of Nevada-Reno announced they could grow livers made up of 20 percent human cells in sheep. Dr. Esmail Zanjani injected either human adult stem cells derived from bone marrow, or human embryonic stem cells, into growing sheep fetuses. Zanjani said he uses sheep because the circulation systems of sheep and humans are similar."
• 2008: Cow eggs with human cells - "British researchers were given approval to conduct human-animal hybrid research in 2008 ... . The nucleus of the cow egg ... was removed, and replaced with the nucleus of a human cell such as a skin cell. Once the egg was allowed to develop and multiply it would become a early-stage cloned embryo called a blastocyst. Scientists could then extract the stem cells from this blastocyst to use in disease treatments."
• February 2010: Mouse-human liver - "Using a mouse that was having liver problems of its own, the researchers replaced its liver with one that was made up of 95 percent human cells to study treatments for Hepatitis. Shown here is a cluster of mouse liver cells that have been replaced with human cells (shown in green). Typically, small animals can't be infected with Hepatitis, only humans and chimps can, but this "humanized" mouse not only became infected, it successfully responded to drug treatments."
• 19 June 2011: Pigs could grow human organs in stem cell breakthrough.

"Is it OK to inject human cells into other animals like laboratory mice and create hybrids? A few weeks ago [in July 2011], scientists announced they had mixed human DNA into cows in order to make them produce human breast milk. (One justification for this was that it would help children in underdeveloped countries.)" Image Source: Zoe.

In research published in 2013, scientists reveal they have implanted human brain cells in mice in order to investigate brain cell functions to treat certain diseases (Hat tip: Evo Terra; George Dvorsky).

Image Source: I09.

I09's coverage reveals that scientists are making animals more human in order to learn more about isolated bits of humanity. This self-limiting focus of our narcissistic species will surely uncover a slew of unintended consequences:

By grafting human glial cells into the brains of mice, neuroscientists were able to "sharply enhance" their cognitive capacities. These improvements included augmentations to memory, learning, and adaptive conditioning. It's a breakthrough that could yield important insights into the treatment of human brain disorders.To conduct the experiment, the scientists created human chimeric mice — mice that were endowed with human glial cells.

... [T]o give mice human glia, the scientists delivered the cells into the brains of normal newborn mice. "We did this by using a narrow glass micropipette to inject 100,000 human glial progenitor cells into each hemisphere of the developing mouse forebrain," said Goldman. This resulted in the widespread integration of human glia into their brain. Once the mice reached adulthood, a large proportion of their forebrain glia were essentially human.

To mitigate any ethical concerns, Goldman told io9 that the grafts were delivered into postnatal animals, they were of cells that could not be transmitted to offspring, and they did not involve neuronal replacement. ...

Once adulthood was reached, the neuroscientists put the mice through four different cognitive tests. The results showed that the humanized mice were markedly different than their unenhanced brethren. ...

Consequently, neuroscientists will now be able to determine the role that glial cells play in these disorders (including failing glial cells), and to do so in live animals. This will present a better method for evaluating potential treatments for human brain disorders.

Looking ahead, Goldman is hoping to engineer humanized mice with glial cells derived from patients with Huntington's Disease, which will allow his team to see if there's any connection to the cognitive deterioration in patients with that disease.

At Slate, Jonathan Moreno asked about the ethics of creating chimeras from the cells of aborted human fetuses and why conservatives were not criticizing this story about mouse-human brain cell experiments:

Last week we learned that people can make smarter mice, but it’s not at all clear what the results of the recent experiment are saying about people.

More than 10 years ago, the distinguished Stanford University biologist Irving Weissman asked his colleague, law professor and ethicist Hank Greely, whether it would be ethically acceptable to grow a mouse with human brain cells. ...

The hypothetical Weissman experiment remained a dormant issue until the mid-'00s. As the implications of stem cell technology came into focus, the mouse brain discussion caught fire among social conservatives. The then-senator, now Kansas Gov. Sam Brownback declared himself a defender of the “unique dignity” of humans, and a candidate for Senate from Delaware had to play down her earlier statements that a mouse with a fully humanized brain had been created. President Bush declared his opposition to “human-animal hybrids” in his 2006 State of the Union address. The throwaway line provided delightful fodder for comedians but left more informed observers wondering whether his speech writers had conflated hybrids with chimeras and nearly everyone else wondering what the heck he was talking about.

Lost in the kerfuffle was the fact that many lab mice are already “chimerized” with a small number of brain cells from human sources, generally far less than 1 percent. These animals could provide important clues to the treatment of serious human diseases and to answer the basic question why human cognitive capacity is so much greater than that of other animals. ...

The purpose of the study was not to make mouse perform better in IQ tests but to learn something about the evolution of human cognition. The work will no doubt enter the pantheon of cases that have sparked questions on both the left and the right about the power and direction of the modern life sciences. How much more adept may laboratory animals be made in order to gain valuable knowledge about ourselves and, perhaps, about the cellular origins of neurological disorders that are so great a burden on human life? In principle similar and perhaps highly informative studies could be undertaken with lower primates, though current rules would prohibit such efforts. These questions are especially pressing now, when attempts to develop better drug therapies for conditions like the dementias have hit a wall.

The new study also appears just as the neuroscience world is anticipating the Obama administration’s announcement of a “brain activity map” project. Fruit flies and zebra fish will be the first experimental models, with the mouse a good decade down the road. The genetics of brain development will be an important component of the new project.

In my book The Body Politic, I argue that the emergence of modern biology has created an unprecedented dilemma for the role of science in the American narrative, a nation that was founded in the spirit of the Enlightenment by people who believed deeply in the spirit of invention, but that also has preserved a commitment to traditional values. Dominion over nature is one of the core assumptions of America’s civic religion, especially if it contributes to human flourishing, as modern medical science surely does. Differing views about how far that dominion extends will continue to be part of America’s biopolitics.

It may be surprising, then, that the general  reaction to the new study was muted. But it may not be that way for long. Furthermore, one can only wonder what the response would have been if the study had been published during the 2012 election season. In national politics, a candidate like Rick Santorum would have been most likely to take up the question. The state level is now the place to watch. Louisiana already has a law criminalizing the creation of human-animal hybrids and, most recently, Mississippi legislators are considering a similar bill.

See another report on the mice with human brain cells story at Scientific American.

References:
S. H. Saey, Mice get brain boost from transplanted human tissue. Science News, Vol. 183 #7, April 6, 2013
Xiaoning Han, et al., Forebrain Engraftment by Human Glial Progenitor Cells Enhances Synaptic Plasticity and Learning in Adult Mice, Cell Stem Cell, vol. 12, No.3, March 7, 2013.

• For a discussion on the ethics of human-animal hybrids and chimeras at National Geographic, go here.
• Another discussion, "The Truth about Chimeras" is at The Science Creative Quarterly here.
• For a summary of the soundness of philosophical arguments used in relation to the problem of human/non-human chimeras, see the Stanford Encyclopedia of Philosophy entry on the topic, here.
• The text of the American bill "S.659 -- Human Chimera Prohibition Act of 2005 (Introduced in Senate - IS)" (17 March 2005) presented to the 109th Congress (which was read twice and is now before a Senate Committee) is here.
• The text of the Canadian law on the matter, the "Assisted Human Reproduction Act" (last amended 30 September 2012), is here. Section 5 prohibits chimera creation: “No person shall knowingly . . . create a chimera, or transplant a chimera into either a human being or a non-human life form” or “…create a hybrid for the purpose of reproduction, or transplant a hybrid into either a human being or a non-human life form.” (Hat tip: The Science Creative Quarterly)

See my related post on stem cells: A Recipe for Millennial Immortality.