Scientists have grown working pituitary glands in the lab that could potentially transform the treatment of people with a range of debilitating hormone disorders.
The team of Japanese researchers grew the tiny hormone-secreting organs using stem cells taken from a mouse embryo. When the tissue was transplanted into mice with pituitary gland defects, it raised levels of the missing hormones in their bodies.
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.
The creation of spare body parts for transplant is one of the goals of stem cell science. Stem cells are the body’s “master cells” and can turn into a range of different types of tissue, such as brain, muscle or pancreatic cells.
Any tissue or organs grown from patients’ own stem cells would not be rejected by the body, doing away with the need for immunosuppressant drugs.
Pituitary glands – the oval, pea-sized organs at the base of the brain – are a particular challenge for stem cell researchers because they are so complex. They have two distinct parts and secrete at least eight hormones regulating growth, fertility, breast milk production, blood pressure, contractions during childbirth, temperature and water balance.
Using mouse stem cells arranged in a three dimensional culture, Dr Sasai’s team mimicked the way pituitary glands develop in the embryo. The resulting tissue contained all five types of cell found in a normal gland and took around three weeks to grow, the scientists report in the journal Nature.
“We have made hundreds of pituitary glands from embryonic stem cells,” said Dr Sasai. When the tissue was transplanted into mice with pituitary defects, levels of missing hormones in their bodies rose to normal.
Although the researchers used embryonic stem cells in their experiment, they believe the technique could work with stem cells derived from adult tissue – so-called induced pluripotent stem cells. That would avoid the ethical concerns some people have about using human embryos in research and therapies.
Even if the scientists can grow a human pituitary, they still face major obstacles in creating a safe and efficient way to transplant it, Dr Sasai said. However, he believes lab-grown glands could lead to treatments for growth hormone deficiencies and damage to the pituitary glands caused by surgery and Sheehan’s syndrome.
Women with Sheehan’s syndrome, which results from blood loss during childbirth, have problems breastfeeding, suffer tiredness, weight gain, constipation, low blood pressure and slowed thinking.
Prof Robin Lovell-Badge, one of Britain’s leading stem cell experts at the Medical Research Council’s National Institute for Medical Research in London, said: “It is unlikely that these in vitro-derived pituitaries are fully developed and make hormones in precisely the same way as normal.
“However, the fact that they got as far as they did is impressive. It suggests that there is a fair amount of self-organisation, which means that it might be easier than we thought to build not just pituitaries, but also other organs from embryonic stem cells and induced pluripotent stem cells – as long as they are not too complex.
“It also opens up new possible ways for treating patients with defective or missing pituitary glands.”
Source: The Guardian, David Derbyshire, http://bit.ly/tS6hhr