Spiderman is Real! Well.. May be Soon
[Posted on: Thursday, August 11, 2016]

Not really, but we might be going down the road to create one with NIH funding. This week, NIH lifted a moratorium on insertion of human stem cells into early stage embryos of non-human vertebrate animals to create human-animal chimera. This represents a unique balance of scientific curiosity, medical benefit, and ethical dilemma.
Human-animal chimeras have dominated our imagination since the beginning of time. Hindu mythology, Egyptian writings, Roman scriptures, and most other religious and philosophical documents are choke-full with descriptions of characters that are partly human and partly animals. In modern times, comics are full of characters such as Spiderman, Cat woman, the “Mutants” in X-Men, and others where a genetic accident or a natural phenomenon created a chimera with super human powers and human conscience. We both revere and fear such fictional characters. In medical research, animal models containing human cells have been used for decades to gain valuable insights into human biology and disease development such as human tumor cells grown in mice to study cancer disease processes and to evaluate potential treatment strategies. Now researchers want to go the next step, introducing human stem cells into early animal embryos to create disease models, test drugs, and eventually human organs for transplantation. On 9 March 2009, in one of his first Executive Actions on taking office President Obama lifted the ban on embryonic stem cell research imposed by the Bush administration. The NIH policy that followed allowed most kind of embryonic stem cell research except inserting human stem cells in the germ line of animals. Last year, NIH further restricted funding of research that incorporated human pluripotent stem cells into early-stage animal embryos leading to an outcry from researchers involved in such research who wanted to lift most restrictions on human-animal research. This week’s partial reversal of the policy allows insertion of human stems cells into embryos of some species but keeps the ban on doing it for neuronal cells and in primates. The reasoning is that the chimera research is sufficiently advanced to control its use only in “beneficial” ways, while still limiting breeding of such chimeras or growing of human brain cells in animal bodies. As is obvious, there is a storm of strong opinions both in favor and against the policy. There are a few facts that should be considered before you pick a side. Animal models used in medical research have several limitations in predicting both safety and efficacy, so we do need models that are closer to humans to avoid unnecessary human testing and expedite development of new drugs. Organs for transplant are in severe shortage due to lack of donors and high organ rejection. Chimeras can potentially solve these issues. However, adding human genome into animals does pose scientific and ethical challenges on controlling the creation of new chimeric species that contain human cells, organs and even may be, “conscience”. The current restrictions are aimed to curtail the Frankenstein scenario but it would be hard. The nature of research is gradual. We jump barriers one by one. Once we show that these models work, the next obvious step would be to breed them so we can reproduce these and create a constant supply of the beneficial organism like we do for transgenic animals. What happens when research in chimera funded by public money is licensed to industry which in turn may take to the next logical level of breeding and neurological research? The current ban on funding does not prohibit privately funded research. Addition of permanent human cells in animals also raises the ethical concerns; should chimera be treated as humans or animals, do they have human rights, do they have an opinion! FDA has not been a visible participant of this discussion as so far it primarily refers to research. In the NIH workshop on this topic, there were no FDA presenters. However, as we see products of this research FDA will need to step in. FDA should have fewer concerns with animal models for testing safety or efficacy. Organ transplant is another story. There are many questions but few clear answers. I guess I will wait till I see a webbed creature hanging by a pole down the street.