Making Thyroid Tissue from Stem Cells

Belgium scientists from the Universite’ Libre de Bruxelles have developed a novel recipe that coaxes stem cells to efficiently form thyroid tissue. Such a finding could be used potentially to treat those patients who have defective thyroid function or suffer from abnormal thyroid gland development.

This research was led by Sabrina Costagliola, who used mouse stem cells for her model system.

The thyroid gland is located just over the voice box (larynx), and it synthesizes and releases thyroid hormone into the bloodstream. Thyroid hormone is the central regulator of basal metabolic levels, and patients who suffer from insufficient thyroid hormone levels tend to gain weight, are lethargic, and lack energy. Thyroid insufficiency tends to run in families and as people age, the effects of thyroid insufficiency tend to take their toll.

Thyroid hormone requires the incorporation of iodide, which is the main reason your mother always told you eat your fish. You need iodide to make thyroid hormone, but you can also get iodide from eating kelp or other types of foods.

1/3,000 babies is born with some form of thyroid insufficiency. Because thyroid hormone is essential for development of the brain, babies with an underactive thyroid are affected by irreversible mental retardation, and life-long hormonal treatment regime is necessary to maintain proper metabolic levels and normal growth patters.

To convert stem cells into thyroid tissue, Costagliola and her research team targeted two important thyroid-specific genes. By transiently expressing these genes in undifferentiated stem cells, they were able to differentiate these cells into “thyrocytes,” which are thyroid gland precursors.

In the next step, Costagliola and her team transplanted these thyrocytes into mice that lack functional thyroid gland. Four weeks after transplantation, the researchers noticed that the recipient mice showed normal levels of thyroid hormone and no longer had any symptoms of thyroid insufficiency.

These results are remarkable, but they are show that Costagliola and her team have designed an excellent model system to study and characterize thyroid development. Secondly, Costagliola’s model system might provide a therapeutic strategy to replace the thyroid gland of patients who have had their thyroid glands extirpated as a treatment for thyroid cancer.

The next step for Costagliola and her team is to replicate this research with human embryonic stem cells, and then with human induced pluripotent stem cells to determine if this protocol is feasible as a treatment regime for human patients.