| 摘要: | 研究動機與目的:
神經相關併發症在慢性腎病 (chronic kidney disease, CKD)或末期腎病 (End
stage renal disease, ESRD)是常見且容易被忽略的議題。在神經相關的併發
症中，認知功能障礙(cognitive impairment)以及動作單元異常所產生的失眠
(例：不寧腿症候群(restless leg syndrome))為臨床會面臨的慢性併發症，且
相關併發症與失眠、心血管疾病與生活機能受損，但神經相關疾病的生物標
記探討相當有限。造成神經併發症的機制中，對於尿毒素所引起的直接神經
性傷害的研究有限，蛋白質鍵結性尿毒素硫酸吲哚酚(indoxyl sulfate)為近年
來廣泛討論之尿毒素，但硫酸吲哚酚在神經細胞的受損機制較少。從過往研
究中發現，透析病患常在腦部合併神經軸突，而軸突受損所導致的認知功能
受損實際機制不明，本論文研究主題將探討有關於indoxyl sulfate 所造成的
神經受損可能機轉以及臨床生物標記在慢性腎病病患合併神經相關併發症運
用
重要研究方法:
本研究主題分為：臨床研究以及細胞實驗。
臨床研究收案針對末期腎病分兩個疾病族群：不寧腿症候群以及認知功能障
礙。不寧腿症候群疾病收案共40 人，根據臨床症狀分組: (1)控制組, (2) 末期腎
病無症狀and (3) 末期腎病合併不寧腿症候群，三組收案中利用多巴胺運轉體
掃描分析並確認紋狀體活性是否與臨床症狀之相關性。認知功能障礙部分，收
案共67 名透析病患，40 位無認知功能異常、23 位有認知功能障礙，分析周邊
血中常用之生物標記如神經輕鍊蛋白、乙型類澱粉等。
細胞實驗上，根據臨床收案確認血液中硫酸吲哚酚與臨床認知量表之相關性，
並選定SH-SY5Y 之人類神經母細胞瘤細胞，並使用維生素A 酸促進細胞分化
為似神經細胞，在分化過程中加入硫酸吲哚酚確認是否會造成細胞凋亡，以確
認硫酸蚓哆酚所導致之神經毒性。
研究結果:
末期腎病合併不寧腿症候群的臨床研究中，發現末期腎病合併不寧腿症候群個
案的多巴胺運轉體掃描顯影較控制組及末期腎病無症狀者低，而多巴胺運轉體
掃描的顯影發現運轉體功能與血液中肌酐酸(creatinine)成反比。末期腎病合併
認知功能障礙的臨床研究中，發現認知功能障礙個案的血液中神經輕鍊蛋白濃
度較高，且該蛋白濃度預測認知功能障礙的信效度分析中，接收者操作特征曲
線曲線下面積為0.65(95%信賴區間: 0.516-0.797, p=0.034)。細胞實驗中，發現
硫酸吲哚酚濃度與認知功能量表呈負相關，而硫酸吲哚酚會造成分化中SHSY5Y
細胞因氧化壓力增加造成細胞凋亡
結論:
慢性腎病病患的常見神經性併發症中，神經輕鍊蛋白可用於協助確認認知功能
障礙之生物標記，尿毒素中的硫酸吲哚酚濃度與認知功能量表成負相關，並造
成分化中神經細胞之細胞凋亡。硫酸吲哚酚所造成的神經軸突傷害或是神經軸
突分化不良，可能是認知功能受損與動作神經元病變的分子機轉，而多巴胺轉
運體掃描在末期腎病的下降，可能來自於硫酸吲哚酚對神經母細胞的傷害
Background and specific aims:
In the patients with end stage renal disease(ESRD), neurologic complications
are common and easily neglected. Neurologic complications could induce
insomnia, further cardiovascular complication and the impairment of activity
in daily life. Cognitive impairment and movement disorder (restless leg
syndrome) are common chronic complications, but the studies on the
biomarkers are few in the patients with chronic kidney disease (CKD).
Recently, indoxyl sulfate, one of the protein bound uremic toxin, is related to
multiple disorders in CKD patients, but studies on mechanism of the IS
mediated neuronal damage are few. The aim of the study is to investigate the
biomarkers in the cognitive impairment and restless leg syndrome in
CKD/ESRD patients and molecular mechanism in the indoxyl sulfate
mediated neuron damage.
Materials and methods:
The study was divided into 2 parts: the clinical investigation and in vitro
study. The clinical investigations two subsets in CKD disease: patients with
restless leg syndrome(n=40) and with cognitive impairment (n=67). In the
restless leg syndrome study, we used Tc-99m TRODAT-1 SPECT as the
biomarkers to evaluate the dopaminergic uptake of striatum in CKD/ESRD
patients with restless leg syndrome. In cognitive impairment study, we
measured the plasma neurologic biomarkers (neurofilament light chain
protein, amyloid beta) in patients with (n=23)and without (n=40) cognitive
impairment. In vitro study, we used indoxyl sulfate to treat the differentiating
SH-SY5Y neuroblastoma cell line by retinoic acid.
Results:
In the study of restless leg syndrome, the ESRD patients with restless leg
syndrome had lower Tc-99m-TRODAT-1 uptake in the striatum than health
control group and the ESRD patients without restless leg syndrome. The
uptake ratio was negatively correlated with the serum concentration of
parathyroid hormone and ferritin. In the study of cognitive impairment,
neurofilament light chain was higher in the ESRD patients with cognitive
impairment, and the area under curve for receiver operating characteristic
curve was 0.65(95% confidence interval: 0.516-0.797, p=0.034). For the in vitro
study, the indoxyl sulfate induced differentiating SH-SY5Y apoptosis by
generative oxidative stress. Indoxyl sulfate was negative correlated with the
scales for cognition in ESRD patients with cognitive impairment.
Conclusion:
In the study of cognitive impairment, neurofilament light chain was a
biomarker for cognitive impairment in ESRD patients. From the in vitro study
with clinical investigation, indoxyl sulfate was negatively correlated with
cognition in ESRD patients. IS induced the apoptosis of the differentiating SHSY5Y cells by generating oxidative stress. The neuronal progenitor cells
surrounded by indoxyl sulfate might not repair the damaged striatum.
Therefore, the decreased TRODAT-1 uptake in ESRD patients might be
associated with the insufficient repairment from neuroblast. The IS mediated
axonal damage might be the possible molecular mechanism in the neurologic
complications in CKD/ESRD patients. |
