Functional thyroid tissue generated from stem cells in mice
16 October 2012
The Université Libre de Bruxelles has developed a protocol
that allows for the first time the efficient generation of functional
thyroid tissue from stem cells in mice. The research is published in the
journal Nature (10th October).
The discovery could allow the treatment of patients who suffer from
thyroid hormone deficiency due to defective function, or abnormal
development of the thyroid gland.
Thyroid hormones are a class of iodide-containing molecules that
play a critical role in the regulation of various body function
including growth, metabolism and heart function and that are crucial
for normal brain development. The thyroid gland, an endocrine organ
that has been specialized in trapping iodide, is the only organ
where these hormones are produced.
It is, however, of note that one out of 3000 human newborns is
born with congenital hypothyroidism, a condition characterized by
insufficient production of thyroid hormones. In the absence of a
medical treatment with thyroid hormones — initiated during the first
days after birth — the child will be affected by an irreversible
mental retardation. Moreover, a life-long hormonal treatment is
necessary in order to maintain proper regulation of growth and
By employing a protocol in which two important genes can be
transiently induced in undifferentiated stem cells, the researchers
at IRIBHM were able to efficiently push the differentiation of stem
cells into thyrocytes, the primary cell type responsible for thyroid
hormone production in the thyroid gland.
A first exciting finding of these studies was the development of
functional thyroid tissue already within the culture dishes. As a
next step, the team of Sabine Costagliola transplanted the
stem-cell-derived thyrocytes into mice lacking a functional thyroid
gland. Four weeks after transplantation, the researchers observed
that transplanted mice had re-established normal levels of thyroid
hormones in their blood and were rescued from the symptoms
associated with thyroid hormone deficiency.
These findings have several important implications. First, the
cell system employed by the IRIBHM group provides a vital tool to
better characterize the molecular processes associated with
embryonic thyroid development. Second, the results of the
transplantation studies open new avenues for the treatment of
thyroid hormone deficiency but also for the replacement of thyroid
tissue in patients suffering from thyroid cancer.
The researchers are currently developing a similar protocol based
on human stem cells and explore ways to generate functional human
thyroid tissue by reprogramming pluripotent stem cells (iPS) derived
from skin cells.