The thyroid is an endocrine gland that produces hormones such as thyroxine and triiodothyronine, which are vital for maintaining human life as they mediate processes such as growth, neurological development, and homeostasis [1]. Therefore, an abnormal function of the thyroid gland or its complete removal due to cancer requires the compensation of the gland’s functions. This compensation is commonly made through hormone replacement therapies [1,2].
With the advent of stem cell technologies, it is now possible to devise cell replacement therapies to compensate for the loss of thyroid function and eliminate patients' subsequent lifetime dependence on synthetic hormone treatment. Shortly, the new advances in 3D bioprinting technology will allow the development of functional and vascularized bioprinted thyroid for transplantation directly into the human body [1,3].
A Russian biotechnology research laboratory designed a bioprinter to build a fully functioning mouse thyroid gland using stem cells taken from the adipose tissue. These cells are combined with a hydrogel and then put into an extruder, equipped with a syringe that drips layers of tissue. As the cells take shape, the hydrogel dissolves, leaving the organ [4,5].
Figure 1: Construct and projection of the thyroid gland designed by the Russian team [6].
As a relatively simple endocrine organ, the researchers assert that the thyroid gland would be suitable for testing the proposed bioprinting technology. They have already announced that, due to the great success of the first surgery in animals, they will also experiment 3D printing of human thyroids as soon as possible. The success of this technique has also paved the way for further research into bioengineered thyroid. [1].
Figure 2: The bioprinter used in the study of the Russian team [6].
In 2019, Jun Pan et al. developed an approach to generate thyroid grafts using a decellularized rat thyroid matrix. First, thyroid glands were isolated from rats and the cells were removed to form a decellularized thyroid scaffold, which was later recellularized with a rat thyroid cell line to reconstruct the thyroid using a perfusion technique. The results indicated that the recellularized thyroid had successful cell engraftment and that specific thyroid functions also remained viable. Furthermore, the decellularized rat thyroid-based scaffold could be recellularized with human-derived thyroid cells to reconstruct a humanized bioartificial endocrine organ, endorsing the potential of this procedure for treating hypothyroidism in humans [7].
REFERENCES
1. Bulanova, E. A. et al. Bioprinting of a functional vascularized mouse thyroid gland construct. Biofabrication 9, 034105 (2017).
2. Eligar, V., Taylor, P. N., Okosieme, O. E., Leese, G. P. & Dayan, C. M. Thyroxine replacement: a clinical endocrinologist’s viewpoint. Annals of Clinical Biochemistry: International Journal of Laboratory Medicine vol. 53 421–433 (2016).
3. Hollenberg, A. N., Choi, J., Serra, M. & Kotton, D. N. Regenerative therapy for hypothyroidism: Mechanisms and possibilities. Mol. Cell. Endocrinol. 445, 35–41 (2017).
4. First ever 3D printed thyroid gland announced by Russia’s 3D bioprinting solutions. Futurism https://futurism.com/first-ever-3d-printed-thyroid-gland-announced-by-russias-3d-bioprinting-solutions (2015).
5. Russian scientists use first-ever 3D printed thyroid gland in successful transplant surgery. https://bioprinting.ru/en/press-center/publications/russian-scientists-use-first-ever-3d-printed-thyroid-gland-in-successful-transplant-surgery/.
6. First Ever 3D Printed Thyroid Gland Announced by Russia’s 3D Bioprinting Solutions - 3DPrint.com. https://3dprint.com/54159/3d-printed-thyroid-mouse/ (2015).
7. Pan, J. et al. Regeneration of a Bioengineered Thyroid Using Decellularized Thyroid Matrix. Thyroid 29, 142–152 (2019).