Torres, Vukosava MilicEsteves, Vanessa Sofia da Silva2025-03-242025-03-2420252024http://hdl.handle.net/10400.5/99644Tese de mestrado, Química (Química), 2025, Universidade de Lisboa, Faculdade de CiênciasParkinson’s disease (PD) is the second most common neurodegenerative disease associated with aging, characterized by progressive loss of dopaminergic neurons in the substantia nigra. PD affects about 10 million people globally, primarily those over 60 years. Current diagnostic methods are solely symptomatic, when disease is in advanced stage with substantial neuronal loss. There’s an urgent need for early and accurate diagnosis of PD to enable timely treatment and improve the patient’s quality of life. This study aimed to develop an analytical workflow to identify potential biomarkers for PD across different stages using untargeted metabolomics. Metabolomic profiling was performed on 16 plasma samples from idiopathic PD patients and 9 control samples, aged 47 to 83, categorized by Hoehn and Yahr (HY) stages. Ultra-performance liquid chromatography coupled with high-resolution mass spectrometry (UPLC-ESI-HR-MS) was used to analyze the samples. The workflow optimization included solvent extraction, mobile phase selection, and chromatographic separation, enhancing metabolite detection sensitivity. Multivariate statistical methods (PCA and PLS-DA) enabled differentiation between disease stages and control groups, with high R² and Q² values indicating strong predictive power. From the PLS-DA analysis, 400 variables of importance (VIP) were identified, leading to the annotation of 46 putative biomarkers. The main findings revealed significant alterations in lipid, bile acid, and steroid metabolism, alongside amino acid biosynthesis and oxidative stress. Glycerophospholipids emerged as a highly enriched pathway, with increased membrane degradation and remodeling. Dysregulated metabolites such as lysophosphatidylcholines, oxidized fatty acids, and sphingomyelins indicate membrane degradation and neuroinflammation. The presence of glycodeoxycholic acid and reduced neuroprotective steroids highlights the role of the gut-brain axis and neuronal vulnerability in PD progression. In summary, this study provides workflow for metabolite extraction and analysis, identifying potential biomarkers for PD staging. These biomarkers offer promising targets for early diagnosis and therapeutic intervention, potentially improving outcomes for PD patients.engDoença de Parkinsonmetabolómicacromatografia liquídaespectrometria de massabiomarcadorTeses de mestrado - 2025master thesis