Theotokis P, Gkantaras A, Avramidou E, Meditskou S, Manthou M E
Aristotle University of Thessaloniki, School of Medicine, Laboratory of Histology and Embryology.
Aristotle University of Thessaloniki, Hippocrateion General Hospital, First Department of Pediatrics, Thessaloniki, Greece.
Acta Endocrinol (Buchar). 2023 Oct-Dec;19(4):415-420. doi: 10.4183/aeb.2023.415. Epub 2024 Jun 24.
Hashimoto thyroiditis (HT) is an autoimmune disorder associated with hypothyroidism. Lymphocyte infiltration leading to thyroid follicular cell destruction is counteracted by increased collagen production, deposition and scarring. However, only recently a specific subpopulation of modified fibroblasts with contractile properties, namely "myofibroblasts" (MFBs) have been linked to HT.
Our ultrastructural study aims to delineate the presence and contribution of MFBs to the fibrotic milieu of HT.
Tissue biopsies were obtained from 5 HT-diagnosed patients and specimens were examined using a Transmission Electron Microscope (TEM).
Histopathological examination indicated extensive microvilli atrophy and atypical vacuolations of the thyroid follicular cells in the HT samples. In addition to interstitial extravasated lymphocytes, capillaries were encircled by MFBs (mean distance from lumen 1.248± 0.43µm) with the characteristic electron-dense α-smooth muscle actin (α-SMA), confirmable in higher magnifications. Myofibroblastic projections were found to have significantly higher representation near the capillary lumen compared to the impaired endothelial lining (P < 0.01).
Our TEM findings suggest that the intrusion of endothelia by myofibroblastic projections can be a significant factor towards the malfunction of follicular cells in HT patients and offer a paradigmal understanding of the ultrastructural interactions that may underlie the HT pathology.
桥本甲状腺炎（HT）是一种与甲状腺功能减退相关的自身免疫性疾病。淋巴细胞浸润导致甲状腺滤泡细胞破坏，而胶原生成、沉积和瘢痕形成增加可对抗这种破坏。然而，直到最近，具有收缩特性的特定修饰成纤维细胞亚群，即“肌成纤维细胞”（MFBs）才与HT相关联。
我们的超微结构研究旨在描绘MFBs在HT纤维化环境中的存在情况及其作用。
从5例确诊为HT的患者身上获取组织活检样本，并使用透射电子显微镜（TEM）对标本进行检查。
组织病理学检查表明，HT样本中的甲状腺滤泡细胞存在广泛的微绒毛萎缩和非典型空泡形成。除了间质中渗出的淋巴细胞外，毛细血管被MFBs环绕（距管腔的平均距离为1.248±0.43µm），这些MFBs具有特征性的电子致密α平滑肌肌动蛋白（α-SMA），在更高放大倍数下可确认。与受损的内皮衬里相比，发现肌成纤维细胞突起在毛细血管腔附近的表现明显更高（P<0.01）。
我们的TEM研究结果表明，肌成纤维细胞突起侵入内皮可能是导致HT患者滤泡细胞功能障碍的一个重要因素，并为可能构成HT病理学基础的超微结构相互作用提供了一个范例性的理解。
