Impairment of endothelium-dependent arterial dilation in Hashimoto's thyroiditis patients with euthyroidism.
OBJECTIVE
Recent studies have shown that immune responses contribute to atherosclerosis, and endothelial dysfunction is an important early event in atherogenesis. The aim of this study was to investigate the alteration of endothelial function in Hashimoto's thyroiditis (HT) patients with euthyroidism.


METHODS
Study subjects included 28 female HT patients with euthyroidism, 23 female HT patients with hypothyroidism, and 22 healthy women. High-resolution ultrasound was used to measure brachial artery diameter at rest, after reactive hyperaemia and after sublingual glyceryltrinitrate (GTN).


RESULTS
Flow-mediated arterial dilation in HT patients with euthyroidism was significantly lower (3.88%) than in controls (4.98%, P = 0.000) and higher than in HT patients with hypothyroidism (3.26%, P < 0.001). Flow-mediated arterial dilation among HT patients with hypothyroidism was significantly lower than that in controls (P = 0.000). GTN-induced arterial dilation, baseline vessel size, and baseline blood flow were not significantly different among the three groups (P > 0.05). On multiple regression analysis, anti-thyroid peroxidase antibody (TPO-Ab), TSH, free T3, low density lipoprotein cholesterol (LDL-C) and lipoprotein (a) [Lp(a)] were found to be significant factors associated with endothelium-dependent arterial dilation.


CONCLUSIONS
Endothelial dysfunction exists in HT patients with euthyroidism. Autoimmune reactivity and an elevated Lp(a) level might be responsible for the endothelial dysfunction.
Xiang
Guang-da
GD
Department of Endocrinology, Wuhan General Hospital of Guangzhou Command, Wuhan 430070, Hubei Province, P. R. China. guangda64@hotmail.com
He
Yu-Sheng
YS
Zhao
Ling-Shuang
LS
Hou
Jie
J
Yue
Ling
L
Xiang
Hui-Juan
HJ
D050197:Atherosclerosis / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001323:Autoantibodies / Q000097:blood; D001916:Brachial Artery / Q000000981:diagnostic imaging; D016022:Case-Control Studies; D008078:Cholesterol, LDL / Q000097:blood; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology*; D005260:Female; D050031:Hashimoto Disease / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology*; D006801:Humans; D007037:Hypothyroidism / Q000378:metabolism / Q000503:physiopathology; D007453:Iodide Peroxidase / Q000276:immunology; D016014:Linear Models; D017270:Lipoprotein(a) / Q000378:metabolism; D008875:Middle Aged; D005996:Nitroglycerin; D012039:Regional Blood Flow; D012044:Regression Analysis; D013972:Thyrotropin / Q000097:blood; D014284:Triiodothyronine / Q000097:blood; D014463:Ultrasonography; D014664:Vasodilation; D014665:Vasodilator Agents
D001323:Autoantibodies; D008078:Cholesterol, LDL; D017270:Lipoprotein(a); D014665:Vasodilator Agents; D014284:Triiodothyronine; D013972:Thyrotropin; D007453:Iodide Peroxidase; D005996:Nitroglycerin