Disorders in lipid metabolism, oxidative stress, and antioxidants in patients with amnestic mild cognitive impairment without major depression

Abstract Background Amnestic mild cognitive impairment (aMCI) is characterized by changes in lipids and oxidative stress (OS). It is crucial to exclude patients with major depression (MDD) to accurately evaluate these biomarkers in aMCI. Aims To examine lipid and oxidative stress biomarkers associated with aMCI versus normal controls. Methods We performed a case-control analysis involving 61 individuals with aMCI (without MDD) and 60 healthy controls. We assessed the severity of aMCI, distress symptoms of old age, and lipid/OS biomarkers. Results The levels of serum -SH groups were significantly higher in individuals with aMCI, while the levels of malondialdehyde (MDA) were significantly lower in the same group. Serum advanced oxidation protein products, glutathione, and folic acid did not show any notable variations. In individuals with aMCI, we observed an elevated apolipoprotein B (ApoB)/ApoA ratio, as well as decreased levels of high-density lipoprotein cholesterol (HDL), ApoA, and a reverse cholesterol transport (RCT) index. The simultaneous presence of aMCI and subclinical depressive symptoms is marked by elevated levels of triglycerides and ApoB, as well as decreased levels of ApoA and HDL. A significant portion of the variability (24.9%) in a quantitative MCI severity score can be attributed to -SH groups, age (positively), MDA and education (inversely). Discussion The alterations in MDA and -SH levels in aMCI may potentially disrupt redox signaling, which can affect cell signaling and homeostatic setpoints. The interaction between aMCI and subclinical depressive symptoms can lead to increased atherogenicity and reduced antiatherogenic protection.