Researchers created pituitary glands straight from mouse embryonic stem cells, and then even transplanted the organs into mice, where they worked like regular pituitary glands.
The work is an important step in forming new treatments for people with hormone disorders (the pituitary gland produces several hormones). It could even someday lead to the lab creation of complex organs such as the heart or kidneys.
According to the Guardian:
Dr. Yoshiki Sasai, who led the study at the RIKEN Centre for Developmental Biology in Kobe, Japan, said, “It is difficult to guess how long it will take, but we hope that we can produce human pituitary tissue in the next three years.” It would take longer to develop techniques to transplant the cells, he added.
Doing so would help people who have pituitary gland disorders. Instead of receiving transplants of foreign cells that require them to take drugs to prevent the body from rejecting the new organ or tissue, they could receive transplants of such organs made from their own cells.
The Japanese researchers published their study in the November 9th issue of Nature.
Growing the complex pituitary
The pea-sized pituitary sits at the base of the brain, from which perch it controls a number of important bodily functions: growth, fertility, blood pressure, water balance and more.
As you would expect of a small organ that does a lot, it has a complex structure. It contains five types of cells and has two distinct parts.
Dr. Sasai and his team got a bunch of mouse stem cells to arrange themselves into a functioning pituitary gland, which meant that the cells spontaneously formed into two types of tissues at once and then organized themselves into layers of tissue.
As the top layer (called the ectoderm) thickened with cells, it eventually curled into itself to form a pouch. Then, hormone-producing cells started forming in the pouch, eventually spilling over around the outside of the pouch. This buildup of sac and cells became the pituitary gland.
From start to finish, it all took three weeks.
The New Scientist quotes Dr. Sasai: “We still don’t know the real mechanics of how the cells make this pouch. I didn’t give special instructions — it happens spontaneously.”
Functional in mice
The scientists then transplanted the glands into mice who had had their pituitaries removed.
Normally mice without pituitaries die within eight weeks. The mice who received the transplants lived, and they began secreting the hormones that were missing from their bodies after the gland’s removal.
photo: Pituitary endocrine cells (in red) on culture day 21. (Yoshiki Sasai, RIKEN Center for Developmental Biolog)