The new success of regenerative medicine: thyroid follicles
Thyroid follicles grown from stem cells
Copper newsA group of researchers from the Free University of Brussels, led by molecular embryologist Sabine Costagliola, has grown a generation of working thyroid follicular cells from stem cells, Nature News reports (Thyroid is the latest success in regenerative medicine).
Stem cells were modified as a result of genetic engineering manipulations with the introduction of genes encoding two proteins, NKX2-1 and PAX-8. Together, these proteins are synthesized only in the thyroid gland. When such genetically modified cells were grown in Petri dishes in the presence of thyroid-stimulating hormone, they turned into thyroid cells.
To become functional, thyroid cells need to organize themselves into volumetric structures – small spherical follicles with a cavity in which, as necessary, iodide, which is part of a number of hormones produced by the thyroid gland, will accumulate.
Thyroid cells derived from stem cells spontaneously grouped into follicles similar to those that make up the normal thyroid gland.
As shown by Costagliola and co-authors, these follicles were able to capture iodides and synthesize thyroid hormones.
"When we started working on the project, we only hoped to get a few cells that can be used to study the physiology of the thyroid gland. We did not expect to get thyroid follicles at all," says the researcher.
At the next stage, the scientists observed the function of follicular stem cells grown from stem cells in a living mouse with hypothyroidism. This condition in mice was caused by injection of radioactive iodine, which accumulates in the thyroid gland, causing its degradation. Four weeks later, as soon as signs of hypothyroidism were established, the mice were transplanted with grown follicles. Of the nine experimental animals with such a transplant, eight were completely cured, their thyroid hormone levels rose to normal.
Similar to previous work on experimental regenerative medicine, in which tissues were grown to replace affected organs (for example, trachea, cornea), the results obtained in mice will have to be reproduced in humans.
According to Costagliola's co-author, Francesco Antonica, it is possible that induced pluripotent stem cells obtained by reprogramming from the cells of patients with hypothyroidism themselves will be used for this. The author of the reprogramming method, Japanese scientist Shinya Yamanaka (Shinya Yamanaka) this week won the Nobel Prize.
The similarity of stem cells grown from the patient's cells can become the starting material for obtaining thyroid follicle cells that will restore the functioning of the patient's gland.
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