Serum and Cerebrospinal Fluid Malondialdehyde Levels in Patients with Mild Cognitive Impairment

Mild cognitive impairment (MCI) is recognized as an intermediate stage between normal aging and dementia. Oxidative stress is implicated in the pathophysiology of neurodegenerative diseases, playing a crucial role. This study aimed to investigate the differences in malondialdehyde (MDA) levels in the serum and cerebrospinal fluid (CSF) of patients with MCI compared to FDA-approved biomarkers, based on age, sex, and education level. Participants aged 55-90 years old were categorized into three groups based on FDA-approved biomarkers, especially the CSF Aβ42/Aβ40 ratio and clinical screening assessments: 30 MCI (A+) patients with abnormal CSF Aβ42/Aβ40 ratios (Group A), 30 MCI (A-) patients with normal CSF Aβ42/Aβ40 ratios (Group B), and 30 healthy (A-) participants with normal CSF Aβ42/Aβ40 ratios (Group C). The measurements of CSF FDA-approved biomarkers were performed using an automated immunochemical method (Fujirebio, Inc.), while MDA determination was performed using a competitive inhibition enzyme immunoassay technique (ELK Biotechnology Co., Ltd.). Our results showed that the mean CSF MDA values were significantly lower in group C than in group A (83 ng/mL vs. 130 ng/mL, <i>p</i> = 0.024) and group B (83 ng/mL vs. 142 ng/mL, <i>p</i> = 0.011), respectively. Differences in serum and CSF MDA levels were presented in the study groups based on sex, age, and education level. These findings suggest that lipid peroxidation, as indicated by CSF MDA, could serve as a potential biomarker for the early recognition of MCI.