Free thyroid transfer to anterolateral thigh for prevention of radiation induced hypothyroidism: An initial experience.

AIM: Radiation induced hypothyroidism (RIHT) is one of the commonest late side effects of radiation therapy and is seen in more than half of patients and affects quality of life significantly. We report our initial experience on feasibility of free microvascular transfer of thyroid gland out of radiation field to prevent development of RIHT. MATERIAL AND METHODS: A prospective pilot study was undertaken during August 2017 to May 2018. Six Patients with stage III/IV patients of oral cavity cancers who required wide excision/composite resections with microvascular free flap (ALT) reconstruction and adjuvant radiation therapy were enrolled. A written informed consent was obtained from all patients prior to the procedure. RESULTS: The mean age of cohort was 51 years with tongue most common site of primary cancer. The free transfer of thyroid gland to anterolateral thigh was done using microvascular technique. The mean additional time for procedure was 51 min. All patients had successful transfer with no associated immediate complications. Patients were followed up with Tc99 scan, USG Doppler and biochemical assay at routine intervals in peri and postoperative period to assess the anatomical and physiological function of the transferred gland. At median follow up of 8 months, 5 patients were euthyroid and remaining one had biochemical hypothyroidism. All patients had functional thyroid gland in anetrolateral thigh. Five patient were alive, one patient died due to disease. CONCLUSION: This is a small and early feasibility study for free thyroid gland transfer and validates the previously published data. The selected group of patients who have high chances of developing RIHT may benefit from this strategy. Further validation of the technique may be explored in a larger cohort.

First Complex Allotransplantation of Neck Organs: Larynx, Trachea, Pharynx, Esophagus, Thyroid, Parathyroid Glands, and Anterior Cervical Wall: A Case Report.

OBJECTIVE: Evaluate the possibility of performing a complex vascular allotransplant of all neck organs including skin. SUMMARY BACKGROUND DATA: There are 2 previous attempts described in the literature, none of them being that complex. The first one is nonfunctional due to chronic rejection, the second one is viable yet considerably limited in complexity (no parathyroids, no skin). METHODS: The allotransplantation was performed simultaneously on 2 adjacent operating rooms, using microsurgical techniques. RESULTS: The patient's voice, breathing through mouth, swallowing, and endocrinal functions have been fully restored. CONCLUSIONS: Achieved results show clearly that such operations performed in selected patients can nearly fully restore functional and aesthetic effects in 1 single procedure.

The bioartificial thyroid: a biotechnological perspective in endocrine organ engineering for transplantation replacement.

A new concept for ex situ endocrine organ bioengineering is presented, focused on the realization of a human bioartificial thyroid gland. It is based on the theoretical assumption and experimental evidence that symmetries in geometrical coordinates of the thyroid tissue remain invariant with respect to developmental, physiological or pathophysiological transformations occuring in the gland architecture. This topological arrangement is dependent upon physical connections established between cells, cell adhesion molecules and extracellular matrix, leading to the view that the thyroid parenchyma behaves like a deformable "putty", moulded onto an elastic stromal/vascular scaffold (SVS) dictating the final morphology of the gland. In particular, we have raised the idea that the geometry of the SVS per se provides pivotal epigenetic information to address the genetically-programmed, thyrocyte and endothelial/vascular proliferation and differentiation towards a functionally mature gland, making organ form a pre-requirementfor organ function. A number of experimental approaches are explored to obtain a reliable replica of a human thyroid SVS, and an informatic simulation is designed based on fractal growth of the thyroid intraparenchymal arterial tree. Various tissue-compatible and degradable synthetic or biomimetic polymers are discussed to act as a template of the thyroid SVS, onto which to co-seed autologous human thyrocyte (TPC) and endothelial/vascular (EVPC) progenitor cells. Harvest and expansion of both TPC and EVPC in primary culture are considered, with specific attention to the selection of normal thyrocytes growing at a satisfactory rate to colonize the synthetic matrix. In addition, both in vitro and in vivo techniques to authenticate TPC and EVPC lineage differentiation are reviewed, including immunocytochemistry, reverse trascriptase-polymerase chain reaction, flow cytomery and proteomics. Finally, analysis of viability of the thyroid construct following implantation in animal hosts is proposed, with the intent to obtain a bioartificial thyroid gland morphologically and functionally adequate for transplantation. We believe that the biotechnological scenario proposed herein may provide a template to construct other, more complex and clinically-relevant bioartificial endocrine organs ex situ, such as human pancreatic islets and the liver, and perhaps a new approach to brain bioengineering.

Syngeneic transplantation of thyroid tissue encapsulated in a cellulose sulphate membrane.

A new, simple encapsulation method, the precipitation of a polyelectrolyte complex membrane of cellulose sulphate and poly(dimethyldiallylammoniumchloride) was investigated in syngeneic thyroid transplantation. Half a thyroid gland was placed beneath the kidney capsule either after being encapsulated or as a non-encapsulated control graft. In normo-thyroid as well as hypothyroid recipients, the grafted tissue was viable for up to 12 weeks. Furthermore, the hypothyroid state, which was characterized by a markedly diminished 125iodine incorporation into the thyroid, no body weight gain and undetectable serum thyroxin concentrations, was compensated by the grafted tissue. The encapsulated grafts showed lower iodine incorporation, T4 secretion and body weight gain when compared with non-encapsulated control grafts. This may be due to a partial restriction of TSH by the capsule membrane. It was concluded that the cellulose sulphate membrane is biocompatible and enables the functional survival of syngeneic grafted tissue.

Bioartificial thyroid. The in vitro culture of microencapsulated rabbit thyroid tissue.

A new technique of encapsulating thyroid tissue with an artificial membrane for protection against immune attack is reported. The membrane was made of calcium alginate and a poly-L-lysin coating. The membrane prevents the diffusion of large molecules such as hemoglobin but freely permits the passage of smaller molecules such as T4 and culture medium 1640. Because larger molecules are barred, the contents of the microcapsules are safe from immune system rejection. In vitro cultured, microencapsulated rabbit thyroid tissue secreted T3 and T4, achieving a concentration of 8.68 +/- 2.93 nmol/L and 245.23 +/- 124.87 nmol/L, after 3 days; this level remained steady for 6 to 9 days of incubation. These microcapsules show promise as a treatment modality and as a possible solution to the problem of immuno-isolation.

[The function of thyroid glands subjected to deep freezing (--196 degrees)]. / Funktsiia shchitovidnoi zhelezy, podvergnutoi glubokomu okhalazhdeniiu (--196 gradusov)

The function of the thyroid gland transplanted after being frozen to --196 degrees C was studied in experiments on rats. The gland was transplanted to thyroidectomized animals. Glands frozen without the use of cryoprotective agents and also in the presence of a cryoprotector--polyethyleneoxide with a mol. wt. of 400 (PEO-400) were used. Besides, a study was made of the effect of different rates of chilling on the thyroid gland. In assessment of the gland function a determination was made of tissue respiration, of I-131 consumption, and blood thyroid hormone content. To assess the cryoprotective effect of PEO-400 and for the choice of its optimal concentration the NMR method and roentgenostructural analysis werea applied. The thyroid gland proved to take and to retain its capacity to hormone formation after its freezing to the temperature of --196 degrees C according to a special program in the presence of PEO-400.