Human pituitary tissue raised hormone levels in one macaque
Human pituitary tissue grown from stem cells increased hormone signaling for six weeks after transplantation into one macaque whose pituitary had been removed. The Nagoya University team placed the tissue under the skin and observed increases in ACTH and cortisol. Immune rejection limited the graft’s function. The experiment has not established the approach as a treatment for people.
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Human tissue increased hormones in a macaque
A team led by Japan’s Nagoya University transplanted pituitary tissue grown from human stem cells into a macaque whose own pituitary gland had been removed. Blood levels of two hormones, ACTH and cortisol, rose for six weeks. Substantial weight loss associated with hormone deficiency slowed during the same period. The experiment, published in Stem Cell Research & Therapy, tested the approach in one primate.[1], [2]
The graft contained hormone-producing cells organized into organoids: small laboratory-grown tissue masses that can act as miniature organs. Researchers placed it under the skin and used immunosuppressive drugs to limit rejection of tissue from another species. Tissue samples taken three months later still contained living transplanted cells, although strong immune rejection limited their function.[1]
Pituitary signaling controls cortisol release
The pituitary sits at the base of the brain and controls hormones involved in growth, metabolism and stress. Adrenocorticotropic hormone, abbreviated ACTH, signals the adrenal glands to release cortisol. Cortisol helps regulate blood pressure, blood sugar and the body’s response to stress. Demand for it changes with stress and the time of day.[1], [2]
People with hormone deficiency can require daily hormone pills for life, but a fixed daily supply cannot fully match those changing needs. The transplant work investigated whether laboratory-grown pituitary tissue could produce hormones naturally after implantation. Its aim was to restore a source of hormone signaling rather than rely solely on daily replacement pills.[1]
Mouse grafts secreted ACTH for more than six months
Before the primate experiment, the team transplanted organoids into mice whose pituitaries had been removed. Grafts beneath the skin, in fat or in muscle secreted ACTH for more than six months. Transplanted mice survived longer than those given no graft, and researchers observed no unwanted tumors or unusual cell growth.[1], [2]
Researchers also searched the macaque’s lungs and liver for organoid tissue that had moved away from the graft site, finding none. First author Tatsuma Kondo said further studies were planned to extend graft longevity and explore safer immunosuppressive methods. The approach has not been established as a human treatment.[1]
