How far can human experiments go?

In a recent attempt to address organ donor shortage, researchers from California have been conducting experiments that involve growing human organs inside pigs.

For the research, they put together human stem cells and the DNA of pigs to create a human-pig embryo. Called a "chimeric" embryo, the result will produce a normal-looking pig, but will have a pancreas with human cells. The procedure was conducted using a gene-editing technique called Crispr, The Guardian noted.

The Crispr technique, as explained by Medicalxpress, involves the removal of the genetic portion of a pig embryo that encodes for a normal pig pancreas. This will be replaced with human stem cells. As a result, the embryo will develop to a normal pig, but with pancreas exactly similar to those of humans

For the initial experiment, they have already successfully cultivated chimeric embryos for 28 days before being terminating them for further observation of the tissues.

The experiment had not been well-received by different animal welfare groups, arguing that it is unethical and that the research could lead to gruesome organ farms.

"Reports of this gruesome experiment, to harvest organs grown inside a pig to transplant into a human body, reads like something out of the dystopian science fiction novel 'Never Let Me Go,' but with animals instead of people," Katy Taylor, director of science at Cruelty Free International, formerly the British Union for the Abolition of Vivisection (BUAV), told Daily Mail UK.

"We are completely opposed to the use of animals to obtain organs for human transplantation," she said, adding that the procedure has been attempted thousands of times, but has failed due to safety issues, differences in species and organ rejection.

Authorities also fear that the process, without knowing its full implications, may cause abnormality to the pig. For example, the presence of human cells might affect the pig's brain.

In 2014, researchers from the National Institutes of Health successfully transplanted a pig's heart into a baboon, leading to questions whether it is really possible to do the same between pigs and humans.

Fox News made mention that pigs have always been valuable in the field of research. Despite physical differences, many of the pig's biological systems are very similar to our ours.

Dr. Michael Swindle, retired veterinary researcher and author of "Swine in the Laboratory" told the news site in an interview: "They have a number of anatomic and physiologic similarities to humans in different systems. They are what's known as a translational research model, so if [something] works in the pig, then it has a high possibility of working in the human."