Shapiro redux: humans edit a new monkey (Introduction)

by David Turell , Friday, November 10, 2023, 19:56 (168 days ago) @ David Turell

A hybrid from an embryo and stem cells from another monkey:

https://www.nature.com/articles/d41586-023-03473-w?utm_source=Live+Audience&utm_cam...

"Scientists have produced an infant ‘chimeric’ monkey by injecting a monkey embryo with stem cells from a genetically distinct donor embryo1. The resulting animal is the first live-born chimeric primate to have a high proportion of cells originating from donor stem cells.

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"But the monkey chimaera had to be euthanized when it was only ten days old because of hypothermia and breathing difficulties, highlighting the need for further optimization of the approach and raising ethical concerns, say researchers.

"Scientists have long sought to make animal chimaeras using embryonic stem cells, which are derived from an embryo’s inner region and can develop into a wide variety of tissues. Such stem cells can be genetically edited before being added to a recipient embryo.

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"Esteban and his colleagues created recipient embryos by collecting eggs from female cynomolgus monkeys (Macaca fascicularis) and fertilizing the eggs.

"Meanwhile, the researchers extracted embryonic stem cells from one-week-old cynomolgus embryos and genetically edited the cells to display a green fluorescent signal. To grow the stem cells in the laboratory, the team finetuned the nutrients and growth-promoting proteins in the liquid in which the stem cells were grown. They then injected up to 20 green embryonic stem cells into each of the recipient embryos, yielding 74 chimeric embryos with a strong fluorescent signal.

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"The team found that, on average, 67% of the cells across the 26 tested tissues, including the brain, lungs and heart, were descendants of the donor stem cells. The highest level of chimerism was seen in the adrenal gland: the progeny of donor stem cells made up 92% of total cells.

"The low birth rate of chimeric monkeys and the poor health of the one survivor suggest that the donor embryonic stem cells did not perfectly match the developmental state of the recipient embryo, says reproductive biologist Zhen Liu at the Chinese Academy of Sciences in Shanghai. The team plans to optimize this in future, he adds.

“This work is both impressive and commendable,” says stem-cell biologist Irene Aksoy at the Stem-cell and Brain Research Institute in Lyon, France, who was not involved in the study.

"The method might be used to grow human organs in pig or non-human primate tissues, says developmental cell biologist Shoukhrat Mitalipov, director of the Oregon Health and Science University in Portland.

“'If we can delete the genes encoding for, say, the kidney, in a large animal such as a pig or primate, we could introduce human cells to produce that organ instead,” he says. But he adds that using human–animal chimaeras for organ collection, especially if human embryonic stem cells contribute to the nervous system, brain or reproductive cells, comes with many ethical concerns." (my bold)

Comment: it turns out, we are not yet God-like. Growing organs in surrogate animals is really God-like and ethically frightening. Can we guarantee perfection when God doesn't?