Background: Recent studies have revealed the presence of zinc and the expression of zinc transporter (ZnT) family members in most endocrine cell types. It has been demonstrated that the ZnT family plays an important role in the synthesis and secretion of different hormones. Furthermore, ZnT8Ab (zinc transporter-8 autoantibodies) together with GADAb (glutamic acid decarboxylase antibodies), IAA (insulin autoantibodies) and IA-2Ab (islet antigen-2 antibodies) are markers of autoimmunity in patients with type 1 diabetes mellitus (T1DM).
Objective and hypotheses: We studied the expression of ZnT8 transporter in thyroid tissues from patients with thyroid nodular goiter (TNG). The study was performed in the group consisting of 17 patients with thyroid nodular hyperplasia (mean age, 17.8 years ±4 years) and patients with pancreatic tumor as a positive controls. Patients were recruited from Polish endocrine centers.
Method: The ZnT8 expression protein was evaluated using immunohistochemistry. The specimens were paraffin embedded tissues, derived from the pediatric patients, who had thyroid nodular hyperplasia. The antibody against ZnT8 was goat polyclonal antibody (Santa Cruz Biotechnology USA; sc-98243). The antigen was retrieval was done using high pH (PTLink DAKO) and antibody was incubated in 4 °C overnight in 1:50 dilution.
Results: In all of the examined cases we observed the ZnT8 expression in the thyroid follicular cells. He staining was strong and diffuse and observed in almost all thyroid follicular cells. The staining was observed in the cytoplasm. However in 2 out of 17 cases we observed C cells hyperplasia and ZnT8 expression was identified in those cells, also in the cytoplasm and the perinuclear area of the hyperplastic C cells.
Conclusion: According to our knowledge this is the first investigation which identified ZnT8 transporter in pediatric thyroid tissues. Further studies in thyrocytes covered by an autoimmune process are scheduled to confirm ZnT8 as a new thyroid autoantigen.
10 - 12 Sep 2016
European Society for Paediatric Endocrinology