Bioethics: Human cells grown in monkey embryos

ETHICS/ SCIENCE & TECHNOLOGY/ GOVERNANCE

Topic:

• GS-4: Ethics and Human Interface 
• GS-3: Science and Technology- developments and their applications and effects in everyday life 
• GS-2: Government policies and interventions for development in various sectors and issues arising out of their design and implementation. 

Bioethics: Human cells grown in monkey embryos

Context: Researchers at the Salk Institute for Biological Studies in the US have for the first time grown human cells in monkey embryos. The results of their work were published in the journal Cell on April 15. 

While the results might imply progress for this particular field of research called “chimera research”, they have also ignited a debate about how ethical studies of this kind are.

What have the researchers done?

• By integrating human cells into the embryos of macaque monkeys, researchers have created what is called a chimeric tool. 
• Chimeras are organisms that are made up of the cells of two distinct species, in this case humans and monkeys. 
• For instance, if this hybrid embryo was placed in the womb of a monkey, it could possibly grow into a new kind of an animal (however this was not the aim of this study).
• In this study, the monkey embryos containing human stem cells stayed alive and grew outside the body for a period of 19 days.

Has such type of research done before?

• Previously, in a 2017 study researchers integrated human cells into pig tissues as they thought that pigs, whose organ size, physiology and anatomy are similar to that of humans, could help them in creating organs that could ultimately be transplanted to humans.
• But this experiment failed and they believe it is because of the large evolutionary distance between pigs and humans (about 90 million years). 
• Therefore, after this experiment, they decided to pick a species that was more closely related to humans, hence macaque monkeys were chosen.

What’s the purpose of chimeric research?

• Researchers believe that this ability to grow cells of two different species together offers scientists a powerful tool for research and medicine, advancing current understanding about early human development, disease onset and progression and ageing. 
• Further, research of this kind could also help in drug evaluation and address the critical need for organ transplantation.
• Researchers note how chimeric tools provide a new platform to study how certain diseases arise. 
  • For instance, a particular gene that is associated with a certain type of cancer could be engineered in a human cell. 
  • Researchers could then study the course of disease progression using the engineered cells in a chimeric model, which may be able to tell them more about the disease than results obtained from an animal model.

But what are the ethical concerns about this?

• Survivability & Infertility of hybrid animals: In 2014, “Geep”, a hybrid between a goat and a sheep, was born (unintentional breeding) in an Irish farm. Mules are another example of a hybrid animal (intentional breeding) that are the result of mating between a female horse and a male donkey. Generally, different species don’t cross-breed and if they do, their offspring don’t survive for long and are prone to infertility.
• Acceptance by Society: While further research into chimeras might lead to progress, which could mean that they could be used as a source of organs for humans, these chimeras would still be a mix of human and non-human cells, a thought that makes many uncomfortable.
• Treatment of other lifeforms: some argue that chimera research has the potential to worsen injustice against animals and also point out the fairness in using part-human animals to meet human needs
• Sceptical about the goal of Chimeras: Researchers have made it clear that the chimeras created with macaques will not be used for human organ transplants but that they nevertheless reveal invaluable information about how human cells develop and integrate. Some scientists, however, are still skeptical since they feel that one of the goals of chimera research is to create organs that can be transplanted to humans.
• Impact on future generation: Tampering with the genetic code in human beings is more controversial, as any such change can be passed down to future generations

Connecting the dots:

• Genetically Modified Crops