ESPE Abstracts

Introduction: Recent studies have revealed the presence of zinc and the expression of zinc transporter (ZnT) family members in most endocrine cell types. It was demonstrated that ZnT family plays an important role in the synthesis and secretion of many hormones. Moreover, recently ZnT8 was described as a newly islet autoantigen in type 1 diabetes.

Materials and methods: We studied the expression of ZnT8 transporter in thyroid tissues from patients with immune and non-immune thyroid diseases. The study was performed in thyroid tissues after thyroidectomy from patients with thyroid non-toxic nodular goiter (NTNG; n=17, mean age 15.8±2.2 years) and cases with Graves’ disease (n=20, mean age 15.6±2.8). In our study we investigated the expression of ZnT8 in human thyroid tissues from patients with immune and non-immune thyroid diseases using immunohistochemistry, Western Blot as well as immunofluorescence analyses. To the best of our knowledge, this is the first investigation which identified ZnT8 protein expression in human thyroid tissues, moreover, confirmed by three different laboratory techniques.

Results: Identification of ZnT8 molecule in the thyroid tissues revealed a higher expression of this protein in patients with Graves' disease (+++) in comparison to patients with NTNG (++). For positive controls with used tissue from patients with pancreatitis (+++). The elevated expression of ZnT8 in the thyroid tissue of patients with GD was observed mainly within the cytoplasm and cytoplasmic membrane in follicular cells and in C cells (membrane-cytoplasmic reaction) with proliferation features. The expression of ZnT8 molecule was detected in patients with Graves' disease (+) in the lymphoid cells nuclei and in C cell groups. The tissue material was additionally subjected to Western blot analysis, which in GD patients showed the presence of ZnT8 in the band p41 (kDa). In patients with NTNG, the degree of expression of ZnT8 proteins was lower and referred to band 41 (kDa). This study showed predominant expression of ZnT8 in band 41 kDa in immune than in non-immune thyroid disorders and confirmed by additional immunofluorescence method. Each thyroid tissue sample obtained from our study patients underwent assessment for the presence of GAPDH using the Western blot method, which confirmed that the tissues were not degraded and indicated high-quality analyses. In conclusion, expression of ZnT8 in thyroid tissues in patient with immune and non-immune thyroid disorders may suggest potential role of ZnT8 as a new thyroid autoanitgen but it requires further study on a larger cohort.