Engineered Pig Stem Cells Bridge The Mouse-human Gap

iPS cells have already been developed from both mice and humans. Both systems will help researchers answer many biological and genetic questions about these cells, but still leave a gap before clinical applications can begin. These iPS cells cannot be tested on humans before thorough safety and efficacy trials in animal models, but the size, physiology and short lifespan of mice makes them less than ideal for these trials.

Duanqing Pei and colleagues turned to a better pre-clinical model: pigs. These large animals share a remarkably similar biology to humans, as evidenced by their already extensive contributions to medicine, such as using pig insulin to treat diabetes or pig heart valves in transplant surgery. The research group modified the current iPS protocols to successfully generate a line of stem cells from a miniature Tibetan pig (whose smaller size would make breeding and maintenance easier). A biochemical analysis revealed these cells expressed the key proteins that would classify them as 'stem cells' and had the ability to differentiate into many other types of cells.

Importantly, these pig iPS cells more closely resembled human stem cells than other animals, confirming their value in pre-clinical studies. The researchers believe porcine iPS technology is an emerging and exciting field that should progress quickly and lead to many applications.