The first case refers to the recent high-level scientific research project that culminated in the creation of chimeras, or organisms made from two different species.
While the project initially began by conducting the experiment on rats and mice, at the end of January it culminated with the human-pig mix, marking the first time a case had been reported in which human stem cells had begun to grow inside another species.
In the experiment, which appeared in the scientific journal "Cell," researchers from various institutes, including Stanford and the Salk Institute in California, injected pig embryos with human stem cells when there were just a few days old and monitored their development for 28 days to see if more human cells would be generated.
Human cells inside a number of the embryos had begun to develop into specialized tissue precursors, however, the success rate of the human cells was overall low, with the majority failing to produce human cells.
Commenting on the case, Spagnolo said this type of "hybridization between human and animal cells" was primarily done to garner more scientific information. "It's important" that this research is done, he said, but cautioned that we can't be "indifferent" to how the information is used.
If a scientist decides to mingle human cells with those of another species in order to create some sort of hybrid being, "this is of course something that can't be accepted because in some way it means using the generation of a life as an instrument to reach one's own ends."
However, if it's done for a purpose other than generating alternate beings, such as growing human organs for transplant, Spagnolo said this would be acceptable.
One thing that's already being proposed, he said, is the possibility of xenografts, i.e. tissue grafts or organ transplants from a donor that is a different species than the recipient.
The idea of doing this, Spagnolo said, is to "inoculate" pigs with human cells, allowing the organs of the pig to receive human antigens, "so when a transplant were done with a liver or heart from the pig inside a (human being), there wouldn't be the rejection that there is normally doing it with other species."
Spagnolo said that using the hybrid cells for organ or tissue transplant "is acceptable because to transfer a human cell to a pig doesn't mean creating a life."
Rather, it allows the pig "to have a genetic patrimony similar to that of a human being to then be able to use the organs to help people," he said, emphasizing the fact that it's not pig cells being injected into human beings, but vice versa.
(Story continues below)
Subscribe to our daily newsletter
So to make a good, informed decision involves first of all seeing "what type of experiments" are being done, deciding from that "whether it's acceptable or not," then looking at what "one intends to produce, what are the objectives one intends to reach."
Pointing to another touchy scientific case that came up recently when an elderly woman in her 80s was held down by her relatives as her doctors euthanized her, Spagnolo said this is the type of murky water which "advanced statements" or living wills wade into in countries where euthanasia and assisted suicide are legal.
The woman, who lived in the Netherlands, had dementia and had reportedly expressed a desire for euthanasia when "the time was right" at an earlier date, but had not done so recently.
When the woman began exhibiting "fear and anger" and was sometimes found to be wandering the halls of her nursing home, the senior doctor at the home determined that the woman's condition meant the time was right, and put a sleep-inducing drug into her coffee so he could administer the lethal injection.
The woman was not consulted, and woke up as the doctor was trying to give the injection. When she fought the procedure, her family members were asked to hold her down while the injection was completed.
"When medicine no longer does what it should" because in a living will someone expresses their desire for assisted suicide, "this statement completely alters the doctor-patient relationship," Spagnolo said.