Endocrine Abstracts

Background: Selenium (Se) is a crucial micronutrient for thyroid gland homeostasis. Acting through iodothyronine deiodinases, it regulates thyroid hormones synthesis and by glutathione peroxidases removes harmful free radicals. The Se role in pathogenesis of autoimmune thyroiditis is currently under investigation. Se supplementation decreases antithyroid antibodies during pregnancy, may prevent from postpartum thyroiditis and is approved for treatment of mild Graves’ ophthalmopathy.

Objectives: We aimed to determine the impact of Se supply on thyroid parameters and antithyroid antibodies in pregnant females and their newborns.

Methods: 115 mother-child pairs without Graves’ disease were recruited at term delivery from obstetric department in one Polish centre. The blood was collected before childbirth in mothers and during the third phase of delivery from the newborns’ cord blood. Se status was assessed by measuring serum Se, selenoprotein P (SELENOP) concentrations and glutathione peroxidase 3 (GPX3) activity. Thyroid assessment encompasses thyrotropin (TSH), free tetraiodothyronine (fT4), free triiodothyronine (fT3), anti-thyroid peroxidase antibodies (a-TPO), anti-thyroglobulin antibodies (a-Tg) and anti-thyrotropin receptor antibodies (TRAb). All parameters were assessed in mothers and newborns.

Results: Majority of mothers and newborns had poor Se status. Newborns with optimal Se supply had lower median TRAb (IQR) concentrations 0.27 (0.07 - 0.37) IU/l, than in Se-deficient group 0.30 (0.30 - 0.56) IU/l, p = 0.02. Similarly, lower TRAb was detected in in Se-sufficient mothers 0.30 (0.27 - 0.70) IU/l, than in Se-deficient 0.63 (0.38 - 0.82) IU/l, with borderline significance (U = 639.5, p = 0.07). Newborns’ TRAb concentrations were negatively correlated with their both Se (R = -0.27, p = 0.011) and SELENOP (R = -0.22, p = 0.038) levels. Additionally, mothers’ selenoproteins correlated positively with children ft4: Se (r = 0.27; p = 0.01) and GPX3 (r = 0.23; p = 0.02).

Conclusions: Proper maternal Se supply may improve newborns’ thyroid parameters and potentially decrease the risk of neonate thyrotoxicosis in the first days of life, by reducing newborns’ TRAb level. Further studies are required to confirm this hypothesis.