Analyse von Tränenflüssigkeit als Biomarkerquelle beim idiopathischen Parkinsonsyndrom
Analysis of tear fluid as a biomarker source in idiopathic Parkinson's syndrome
by Hannah Linda Jane Paul
Date of Examination:2024-06-05
Date of issue:2024-06-13
Advisor:Prof. Dr. Paul Lingor
Referee:PD Dr. Christian van Oterendorp
Referee:Prof. Dr. Margarete Schön
Persistent Address:
http://dx.doi.org/10.53846/goediss-10491
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Abstract
English
Background: The idiopathic Parkinson´s syndrome is one the second most common neurodegenerative diseases in the world. The diagnosis is to this day a mainly clinical diagnosis. The accuracy of the diagnosis is depending on the expertise of the person performing the examination. Different studies already analyzed a large amount of different potential biomarker sources, such as cerebrospinal fluid, blood and brain homogenate. Another promising candidate as a potential biomarker is tear fluid. Tear fluid is considered an easily accessible body fluid which contains a vast number of proteins which could be influenced by neurodegenerative diseases and is already used as a biomarker source of several ophthalmological disorders. In this study we analyzed the proteins Apolipoprotein A1 (Apo A1), Gelsolin, Profilin 1, Glypican 4 and Apolipoprotein E (Apo E) in the tear fluid of Parkinson´s disease (PD) patients and controls. Those proteins were chosen because of their link to neurodegeneration and because of a previously done study by Boeger et al. which described the proteins Apo A1, Gelsolin and Profilin 1 as significantly regulated in the tear fluid of PD patients compared to controls. Methods: Tear fluid samples of 36 PD patients and 36 age matched and gender matched controls were collected via Schirmer tear test strips. Those samples were analyzed via western blot. Clinical data such as age, gender, ophthalmological diseases und Unified Parkinson`s disease rating scale 3, Hoehn & Yahr-stadium, Montreal cognitive assessment (MoCa) and Parkinson´s disease non-motor symptoms were correlated with the results of the western blots. Results: There was no significant regulation between the PD and control cohorts for any of the proteins examined. However, a breakdown by gender into male and female revealed a significant regulation between the Glypican 4 values of the men and women in the PD cohort. The glypican 4 values of the men were significantly higher. In line with this, there was a non-significant trend for increased Apo A1 values in the men of the PD cohort compared to the values of the women of the PD cohort. When the clinical characteristics were correlated with the proteins examined, significant and positive correlations were found between the proteins Apo A1, Gelsolin, Profilin 1, Glypican 4 and the age of the PD cohort. In addition, there were significant correlations between the proteins in the PD cohort. Profilin 1 was the only one of the proteins examined to show a significant correlation with the protein content of the samples in both the PD cohort and the control cohort. There was also a significant, negative correlation between the MoCA score and the Apo A1 values of the PD cohort. Conclusion: In summary, tear fluid presented itself as an easily accessible material for the search for a biomarker. There was a trend for reduced tear secretion in PD patients and a significantly reduced protein content in the tear fluid of the PD cohort. Gender and age could potentially influence the occurrence of individual proteins in tears and should be taken into account in future searches for biomarkers.
Keywords: neurodegenerative diseases; Parkinson`s disease; tear fluid; biomarker
Schlagwörter: Parkinsonsyndrom; Tränenflüssigkeit; Biomarker
