Meghan Bialt-DeCelie – ’19

Currently in the United States, 76,000 patients are deprived of potentially life-saving organ transplants. The supply of donated organs relies heavily on the number of recently deceased individuals, limiting the supply’s availability. Dr. Yomoyuki Yamaguchi and his team of researchers from Stanford University and the University of Tokyo are exploring more sustainable methods of generating functional tissues and organs to help reduce this number.

The research team investigated the use of pluripotent stem cells in organ development (PSC). PSC’s are undifferentiated, so they can potentially become any type of cell. In recent studies, researchers used the PSCs of pancreas rats and grew functional pancreas cells in a pancreas deficient mouse by interspecies blastocyst complementation. They injected rat PSCs into the blastocyst of a mouse so that the mouse would grow with a rat’s tissue inside.

However, the experiment encountered a complication: the mouse-grown, rat pancreas was the size of a mouse pancreas, and therefore not enough of the organ was produced to be successfully functional in a rat. Researchers decided to flip their methods to address the size issue. Instead of a mouse growing a rat pancreas, they induced a rat to grow a mouse pancreas. The team then transplanted the insulin-producing islets from the rat into mice with diabetes and successfully lowered its blood glucose level for over a year.

Researchers removed the transplanted islet from the mice to see if the islets were responsible for the reduced blood glucose level. Within two weeks after removal, their blood glucose level tripled. The mice had reduced blood glucose using the transplanted islets without the need for immunosuppressant medications after the 5 days after the transplant. This is significant because typically after a transplant, one would continuously require immunosuppressant treatment to prevent rejection of the organ.

This procedure can potentially be translated to any organ or tissue. As promising as this study may seem for the realm of human transplant research, ethical issues regarding interspecies transplants are apparent.

References:

1. Yamaguchi, Tomoyuki, et al, Interspecies organogenesis generates autologous functional islets. Nature(2017). doi:10.1038/nature21070.
2. Image retrieved from: https://upload.wikimedia.org/wikipedia/commons/e/e8/ChimericMouseWithPups.jpg