Bilirubin in Parkinson's disease: pathogenic mechanisms and therapeutic potentials.

Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder, significantly impacting patients' quality of life. Although extensive research has focused on identifying biomarkers, PD diagnosis still relies heavily on clinical features. Current treatments are primarily symptomatic and fail to halt disease progression. Emerging evidence suggests that abnormal bilirubin (BR) levels correlate with PD severity and motor outcomes, highlighting BR's potential as both a biomarker and a therapeutic target. This review elucidates the dual role of BR in PD pathogenesis-modulating oxidative stress, neuroinflammation, and mitochondrial dysfunction-and discusses novel BR-based therapeutic strategies.