In Spain it is estimated that 52,000 people suffer from a chronic kidney disease that will require dialysis or kidney transplantation. Currently, 4,500 Spaniards await a new kidney and, although Spain is the country with the shortest waiting list for this intervention, more donors are needed. But what if it were possible to grow them in the laboratory?
Researchers from the National Institute of Physiological Sciences of Japan have successfully developed functional mouse kidneys within rats with only a few donor stem cells. An advance, published in "Nature" and that could be the basis to generate human organs in cattle from our stem cells, explained one of the authors of the study Masumi Hirabayashi.
The method that the Japanese team used with the rats is called blastocyte supplementation. What does it consist of? Blastocysts (which are the groups of cells that are created several days after the fertilization of the ovule) are taken from animals that have had a specific organ removed in the laboratory and injected with stem cells from a healthy donor. necessarily of the same species (in this case the mouse). Then, the stem cells differentiate to form the entire missing organ.
This technique had previously been used to generate rat pancreas. And as it was successful, it was tried to use to generate kidneys. Although initial attempts to grow mouse kidneys in rats were initially unsuccessful – because the stem cells were not easily differentiated from the other two types of cells needed for kidney formation – the reverse scenario was tried and worked: stem cells of mice if they were differentiated in the blasts of the rats forming basic structures of the kidney. After being implanted in pseudo-pregnant rats, the complemented blastocysts matured in normal fetuses and se found that two thirds of the resulting fetuses contained a pair of kidneys derived from mouse stem cells. The organs were intact and could produce urine.
Could this method be used to create human organs in animals for subsequent transplantation? The researchers respond that first we must make a pattern of the function and architecture of the kidney in depth, analyze how to overcome the barrier between more different species (humans and cattle) and, finally, but perhaps most importantly, toembroider the ethical considerations regarding its use.