Redox Imbalance Associates with Clinical Worsening in Spinocerebellar Ataxia Type 2

BACKGROUND: Spinocerebellar ataxia type 2 (SCA2) is a neurodegenerative disease presenting with redox imbalance. However, the nature and implications of redox imbalance in SCA2 physiopathology have not been fully understood. OBJECTIVE: The objective of this study is to assess the redox imbalance and its association with disease severity in SCA2 mutation carriers. METHODS: A case-control study was conducted involving molecularly confirmed SCA2 patients, presymptomatic individuals, and healthy controls. Several antioxidant parameters were assessed, including serum thiol concentration and the superoxide dismutase, catalase, and glutathione S-transferase enzymatic activities. Also, several prooxidant parameters were evaluated, including thiobarbituric acid-reactive species and protein carbonyl concentrations. Damage, protective, and OXY scores were computed. Clinical correlates were established. RESULTS: Significant differences were found between comparison groups for redox markers, including protein carbonyl concentration (F = 3.30; p = 0.041), glutathione S-transferase activity (F = 4.88; p = 0.009), and damage (F = 3.20; p = 0.045), protection (F = 12.75; p < 0.001), and OXY (F = 7.29; p = 0.001) scores. Protein carbonyl concentration was positively correlated with CAG repeat length (r = 0.27; p = 0.022), while both protein carbonyl concentration (r = −0.27; p = 0.018) and OXY score (r = −0.25; p = 0.013) were inversely correlated to the disease duration. Increasing levels of antioxidants and decreasing levels of prooxidant parameters were associated with clinical worsening. CONCLUSIONS: There is a disruption of redox balance in SCA2 mutation carriers which depends on the disease stage. Besides, redox changes associate with markers of disease severity, suggesting a link between disruption of redox balance and SCA2 physiopathology.