• Thu. Sep 28th, 2023

Home Office set to allow human-animal chimeras

ByRuairi Mackenzie

Jan 28, 2016

Image: Ben Salter

Controversial new research that has allowed the creation of human-animal chimeras in American research labs could be given the green light on British soil. Next week, the Home Office’s Animals in Science Regulation Unit (ASRU) is likely to approve a procedure that involves the transfer of human stem cells, which have the potential to specialise into any desired cell type, into animal hosts such as pigs and sheep. Researchers currently using early versions of the technique say these procedures have the potential to provide patients suffering from failing organs with a supply of replacements that, unlike organs transplanted from human organ donors, would be automatically matched to the recipient’s genotype and would not provoke an immune response, greatly improving post-operative health. Critics of the technique warn of the risk of creating hybrids with human-level intelligence.

How great is the risk of Moreau-like hybrids being created, and how pressing is the need to conduct chimera research? Hiromitsu Nakauchi, a researcher at Stanford University, quantifies the risk thusly: “If the extent of human cells is 0.5 per cent, it’s very unlikely to get thinking pigs or standing sheep”, and indeed current levels of DNA incorporated into chimeras are very low – the hybrids envisioned in sensationalist publications reporting this story would need to be 50 per cent human to be classed as a hybrid. Chimeras, which are the product of this current research, would only have a very small percentage of human DNA.

Chimeras are not necessarily a brand-new creation – as far back as 1984, Nature published details of an experiment which produced a ‘geep’, or a goat-sheep chimera. What modern techniques have given chimera research is the ability to fine tune what stem cells are added, and at what stage of development, explaining how Nakuchi’s experiments may yield a perfectly healthy mouse, which happens to have a pancreas created from rat cells.

Public understanding of experiments involving animals are poor, as scientists are unwilling or unable to communicate the benefits of such research, which will inevitably be slandered in the press as ‘inhumane’ or ‘playing god’. Consequently, experiments that involve combining the DNA of humans and animals are even less well explained, and it really is up to science to make clear the regulatory process, including the ASRU, which forms ethical barriers to the creation of ‘Rise of the Planet of the Geep’. The idea that scientists could jump from the creation of a sheep with a human pancreas, to a sheep with a human brain overnight is absurd, and current chimera research has not produced live human-animal chimeras – once again due to the braking process of regulatory committees. While some scientists inevitably view this process as bureaucratic and a hindrance to progress, debate around these issues is essential, and the death of a patient in a French drug trial just a few days ago should remind scientists that even in carefully planned experimentation, unexpected results with serious consequences are a constant risk.

Organ donation rates actually fell last year in the UK, and in 40 per cent of post-mortem donations, family members intervene to prevent donation. This means ever spiralling waiting times for organs and the suffering of still-alive patients. While chimeras are a promising avenue of research that could solve this problem, increasing donor rates is an equally important task.

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