Thyroid Hormone Deiodinases and Receptors Are Expressed in Human Endothelial Cells

The endothelial system acts as a large endocrine organ in the human body, however, little is still known about the regulative role of THs on endothelial cells. The present study aims to investigate the expression of the TH deiodinases (D1, D2, D3) and TH receptors (TR1, TR2 and TR1) in an endothelial microvascular cultured cell model (HMEC-1), after stimulation with triiodothyronine (T3, 10-100nM), thyroxine (T4, 10-100nM), and reverse T3 (rT3, 1-10nM). The main result of the study is that the TH deiodinases and receptors are expressed in endothelial HMEC-1 cells. These findings might be of significant clinical relevance, given the important regulatory role of the endothelium as first barrier to the bloodstream.