Peripheral Oxidative Stress Markers in Schizophrenia: Insights from Erythrocyte Glutathione Peroxidase, Plasma Malondialdehyde, and Trace Element Ratios in Algerian Patients.

Emerging evidence implicates an imbalance between oxidative processes and antioxidant defense, leading to oxidative stress (OS) in the pathophysiology of schizophrenia (SCZ). Trace elements, essential for neurophysiological functions and antioxidant defenses, may contribute to SCZ onset and progression when dysregulated. This study assessed the plasma levels of malondialdehyde (MDA) and erythrocyte glutathione peroxidase (GPX1) activity in Algerian patients with SCZ. It also measured the plasma concentrations of copper (Cu), zinc (Zn), and selenium (Se), as well as the Cu/Zn, Cu/Se, and Zn/Se ratios. These parameters were studied to evaluate their potential as peripheral biomarkers of central OS. A total of 42 male patients and 54 age- and sex-matched controls were enrolled. The patients were recruited from a charitable facility. Trace element levels were determined using a polarographic analyzer. MDA concentrations in plasma and GPX1 activity in erythrocytes were measured using spectrophotometric methods. Plasma MDA levels were higher in patients than in controls (0.748 ± 0.117 µmol/L vs 0.655 ± 0.080 µmol/L; p < 0.05), and GPX1 activity was lower in patients (86.17 ± 14.95 U/gHb vs 111.20 ± 22.65 U/gHb; p < 0.05). Plasma Cu, Zn, and Se levels were lower in patients, and the Cu/Zn, Cu/Se, and Zn/Se ratios were higher than in controls (p < 0.05). The logistic regression model identified the Cu/Se ratio as a factor associated with SCZ risk (OR = 1.535; 95% CI = 1.046-2.254; p = 0.029). Elevated MDA, reduced GPX1 activity, and trace element imbalance may be linked to OS in Algerian patients. The Cu/Se ratio is emerging as a potential peripheral biomarker associated with SCZ.