Chinese scientists have grown humanized kidneys in pigs for the first time, in a landmark advance that could one day help with organ donor shortages. The project involved producing human-pig chimeric embryos with a mix of human and pig cells and then implanting them into surrogate pig moms. The findings were published in the journal Cell Stem Cell on Thursday (September 7).
Scientists determined that the kidneys were not totally human since they contained vasculature and nerves derived primarily from pig cells, implying that they could not be used for transplantation in their current form.
It is unknown whether existing genetic engineering techniques could be used to create a completely human organ.
Significant progress
The Guangzhou Institutes of Biomedicine and Health experts stated that their primary focus was on developing kidneys because they are the most routinely transplanted organ in human medicine.
“Rat organs have been produced in mice, and mouse organs have been produced in rats, but previous attempts to grow human organs in pigs have not succeeded,” said the senior author Liangxue Lai, of the Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences and Wuyi University.
“Our approach improves the integration of human cells into recipient tissues and allows us to grow human organs in pigs.”
According to the Guardian, another reason this scientific accomplishment is being celebrated is that earlier attempts at making human-pig hybrids have failed because pig cells tend to outcompete human cells throughout development, resulting in a chimera that is almost totally pig.
More research is required
The Chinese researchers surmounted this obstacle by genetically modifying a single-cell pig embryo to lack two genes required for kidney development. This approach generated a niche within the embryo that human embryonic stem cells incorporated into the pig embryo could fill.
“Although this approach is a clear milestone and the first successful attempt to grow whole organs containing human cells in pigs, the proportion of human cells in the generated kidneys is still not high enough,” Darius Widera, a professor of stem cell biology at England’s University of Reading, told AFP news agency.