Selenium exerts protective effects against oxidative stress and cell damage in human thyrocytes and fibroblasts.

PURPOSE: Selenium, incorporated into specific seleno-enzymes, is essential to proper thyroid function and protect cells from oxidative damage induced by H2O2 during thyroid hormone synthesis. Several studies indicated that low selenium levels are associated with thyroid autoimmunity and related disorders, but real effectiveness of selenium supplementation in such diseases is still controversial. We evaluated the effect of selenium on oxidative damage in human thyrocytes and thyroid fibroblasts in vitro. METHODS: To induce oxidative stress, primary cultures were exposed to H2O2, in the presence or the absence of selenium, as either selenomethionine or selenite. We performed the following assays: cell viability, caspase-3 activity, BCL-2/BAX gene expression, DNA fragmentation, malondialdehyde levels, and glutathione peroxidase (GPx) activity measurements. RESULTS: Thyrocytes and thyroid fibroblasts exposed to H2O2 and preincubated with both selenocompounds displayed a significant dose-dependent increase in cell viability compared to cells incubated with H2O2 alone. Pretreatment with selenomethionine and selenite significantly reduced caspase-3 activity and BAX mRNA levels and increased BCL-2 mRNA levels in a dose-dependent manner. Accordingly, H2O2 induced a diffuse pattern of DNA degradation and an increase in malondialdehyde levels, which was prevented by the pretreatment with both selenomethionine and selenite. Both selenocompounds induced an increase in GPx activity, suggesting that these protective effects may be, almost in part, mediated by these selenoproteins. CONCLUSION: In human thyrocytes and fibroblasts in vitro, selenium exerts protective effects against H2O2 in a dose-dependent manner, being selenite effective at lower doses than selenomethionine.

Serenoa repens as an Endocrine Disruptor in a 10-Year-Old Young Girl: A New Case Report.

Serenoa repens, commonly known as saw palmetto, is the sole species currently classified in the genus Serenoa. The plant is a low shrubby palm that is native of West Indies, and it grows in the coastal lands of North America and other European mediterranean countries. Its fruits contain high concentrations of fatty acids and phytosterols. S. repens extracts have been studied for the symptomatic treatment of benign prostatic hyperplasia. Recently, they have been proposed to treat androgenic alopecia and other hair disorders. We report a new case of hot flashes in a 10-year-old girl using a food supplement containing the extract of S. repens for the treatment of hirsutism. When the girl discontinued the treatment, the hot flashes stopped. A 'rechallenge' of the supplement was tried and symptoms reappeared. About 4 months after starting therapy, the girl experienced menarche. Exposure to the plant-derived product could be responsible for the appearance of menarche. In our opinion, use of phytotherapeutic agents in pediatric patients should be associated to a better evaluation of benefit/risk profile taking in account the physiological changes that occurs at different ages in this subgroup of population.