Vanderstraeten Jessica, Derradji Hanane, Craps Julie, Sonveaux Pierre, Colin Ides M, Many Marie-Christine, Gérard Anne-Catherine
Pole of Experimental Morphology, Institute of Experimental and Clinical Research (IREC), Catholic University of Louvain (UCL), Brussels, Belgium.
Radiobiology Unit, Belgian Nuclear Research Centre (SCK-CEN), Mol, Belgium.
Histol Histopathol. 2016 Aug;31(8):897-909. doi: 10.14670/HH-11-727. Epub 2016 Feb 3.
Despite efforts to optimize iodine supply in iodine deficient countries, iodine deficiency (ID) remains a global problem worldwide. Activation of the local microvasculature by ID in the thyroid gland aims at improving the local supply of iodide. For this purpose, the thyrocytes secrete vascular endothelial growth factor (VEGF) that acts on adjacent capillaries, via a reactive oxygen species (ROS)/Hypoxia Inducible factor (HIF)-dependent pathway. Beside the thyroid, other organs including salivary glands and the stomach do express the sodium/iodide symporter (NIS) and are able to take iodide up, potentially rendering them sensitive to ID. To verify this hypothesis, ID-induced effects on the local microvasculature were studied in salivary glands and in the stomach. ID was induced by feeding young mice with an iodide-deficient diet and NIS inhibitor perchlorate in the drinking water. In salivary glands, ID induced a transient increase in HIF-1α protein expression accompanied by a transient, VEGF-dependent increase in blood flow. In the gastric mucosa, ID transiently increased VEGF expression in the mucin-secreting epithelium and in ghrelin-secreting endocrine cells. These observations suggest that microvascular changes in response to ID occur in NIS-expressing tissues other than the thyroid. NIS expressing cells could be viewed as iodide sensors that respond to ID by inducing vascular changes, probably to optimize iodide bioavailability at regional or systemic levels.
尽管在碘缺乏国家努力优化碘供应，但碘缺乏在全球范围内仍是一个全球性问题。甲状腺中碘缺乏激活局部微血管系统旨在改善碘化物的局部供应。为此，甲状腺细胞分泌血管内皮生长因子（VEGF），其通过活性氧（ROS）/缺氧诱导因子（HIF）依赖性途径作用于相邻毛细血管。除甲状腺外，包括唾液腺和胃在内的其他器官确实表达钠/碘同向转运体（NIS）并能够摄取碘化物，这可能使它们对碘缺乏敏感。为了验证这一假设，研究了碘缺乏对唾液腺和胃局部微血管系统的影响。通过给幼鼠喂食缺碘饮食并在饮用水中添加NIS抑制剂高氯酸盐来诱导碘缺乏。在唾液腺中，碘缺乏诱导HIF-1α蛋白表达短暂增加，同时伴有短暂的、VEGF依赖性血流增加。在胃黏膜中，碘缺乏使分泌黏蛋白的上皮细胞和分泌胃饥饿素的内分泌细胞中的VEGF表达短暂增加。这些观察结果表明，除甲状腺外，表达NIS的组织中也会发生对碘缺乏的微血管变化。表达NIS的细胞可被视为碘化物传感器，通过诱导血管变化对碘缺乏作出反应，这可能是为了在区域或系统水平优化碘化物的生物利用度。
