Institute of Medicine, Department of Internal Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Institute of Medicine, Department of Internal Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Psychoneuroendocrinology. 2020 Nov;121:104844. doi: 10.1016/j.psyneuen.2020.104844. Epub 2020 Aug 17.
Epidemiological studies have linked higher levels of thyroid hormones (THs) to increased risk of Alzheimer's disease (AD), whereas in advanced AD, THs have been unchanged or even decreased. In early AD dementia, little is known whether THs are related to AD neuropathology or brain morphology.
This was a cross-sectional study of 36 euthyroid AD patients and 34 healthy controls recruited at a single memory clinic. Levels of THs were measured in serum and cerebrospinal fluid (CSF). In addition, we determined AD biomarkers (amyloid-β, total tau and phosphorylated tau) in CSF and hippocampal and amygdalar volumes using magnetic resonance imaging.
Serum free thyroxine (FT4) levels were elevated, whereas serum free triiodothyronine (FT3)/FT4 and total T3 (TT3)/total T4 (TT4) ratios were decreased, in AD patients compared to controls. In addition, serum TT4 was marginally higher in AD (p = 0.05 vs. the controls). Other TH levels in serum as well as CSF concentrations of THs were similar in both groups, and there were no correlations between THs and CSF AD biomarkers. However, serum FT3 correlated positively with left amygdalar volume in AD patients and serum TT3 correlated positively with left and right hippocampal volume in controls.
Thyroid hormones were moderately altered in mild AD dementia with increased serum FT4, and in addition, the reduced T3/T4 ratios may suggest decreased peripheral conversion of T4 to T3. Furthermore, serum T3 levels were related to brain structures involved in AD development.
流行病学研究表明，甲状腺激素（THs）水平升高与阿尔茨海默病（AD）风险增加有关，而在 AD 晚期，THs 水平保持不变甚至降低。在早期 AD 痴呆中，THs 是否与 AD 神经病理学或脑形态有关知之甚少。
这是一项在单个记忆诊所招募的 36 名甲状腺功能正常的 AD 患者和 34 名健康对照者的横断面研究。在血清和脑脊液（CSF）中测量 TH 水平。此外，我们使用磁共振成像确定了 CSF 和海马体及杏仁核体积中的 AD 生物标志物（β-淀粉样蛋白、总 tau 和磷酸化 tau）。
与对照组相比，AD 患者的血清游离甲状腺素（FT4）水平升高，而血清游离三碘甲状腺原氨酸（FT3）/FT4 和总 T3（TT3）/总 T4（TT4）比值降低。此外，AD 患者的血清 TT4 略高（p=0.05 与对照组相比）。两组血清中其他 TH 水平以及 CSF 中 TH 浓度相似，TH 与 CSF AD 生物标志物之间无相关性。然而，血清 FT3 与 AD 患者左侧杏仁核体积呈正相关，血清 TT3 与对照组左侧和右侧海马体体积呈正相关。
轻度 AD 痴呆患者的甲状腺激素水平中度改变，血清 FT4 升高，此外，T3/T4 比值降低可能表明 T4 向 T3 的外周转化减少。此外，血清 T3 水平与 AD 发病相关的脑结构有关。
