A study on the relationship between intraglandular arterial distribution and thyroid lobe shape: implications for...

We have recently hypothesized that structural and secretory components of the adult human thyroid gland maintain constant reciprocal and geometrical relationships, even if changes occur in the three-dimensional (3D) architecture of any of these elements. This means that thyroid morphology could be studied from the point of view of a 3D topology. As a consequence, we have investigated anatomical aspects that could support this assumption. In the present study, we show that the presence of a constant relationship can be demonstrated between the vascular arrangement of the gland, including the extension of intraglandular arterial fields, arterial anastomoses and arterial calibers, and the shape as well as volume of the thyroid. Specifically, a statistically significant difference has been found between the network amplitudes of the superior and inferior thyroid arteries in relation to either a conic or an ellipsoidal geometry of the thyroid lobe. In addition, a direct relationship has been implicated between the distribution of arterial anastomoses and the behavior of the lobe as a single hemodynamic unit. Finally, a statistically significant correlation has been observed between average arterial caliber of the inferior thyroid artery and thyroid volume. On the basis of these results, we propose a model of architectural assembly between stromal and parenchymal elements of the adult thyroid that might prove useful in designing a bioartificial gland ex situ. Potential clinical applications of this principle in regenerative medicine of other endocrine organs are highlighted.