Vitamin D Increases Aβ140 Plasma Levels and Protects Lymphocytes from Oxidative Death in Mild Cognitive Impairment Patients

Area of Science:

• Neuroscience
• Metabolic Medicine
• Gerontology

Background:

• Mild cognitive impairment (MCI) progresses to dementia; vitamin D deficiency is a risk factor.
• Vitamin D aids in clearing brain beta-amyloid (Aβ), a hallmark of neurodegeneration.
• Lymphocytes in Alzheimer's disease (AD) patients show increased oxidative death susceptibility, but in vivo modifiability is unknown.

Purpose of the Study:

• To investigate if correcting low vitamin D levels protects lymphocytes from oxidative stress.
• To determine if vitamin D supplementation increases plasma Aβ1-40 levels in MCI and very early AD (VEAD) patients.
• To assess the impact of vitamin D on cognitive function in MCI and VEAD patients.

Main Methods:

• Evaluated 16 MCI, 11 VEAD, and 25 healthy controls (HC) using cognitive tests (CDR, MoCA, MIS).
• Measured lymphocyte susceptibility to hydrogen peroxide (H2O2)-induced death via flow cytometry.
• Assessed lymphocyte death, plasma Aβ1-40, and cognitive status pre- and post-6-month vitamin D supplementation in participants with low vitamin D levels.

Main Results:

• MCI and VEAD patients exhibited higher lymphocyte oxidative death susceptibility at baseline.
• Vitamin D supplementation improved lymphocyte H2O2-death resistance and plasma Aβ1-40 levels in MCI patients only.
• MCI patients showed improved cognitive status at 18-month follow-up after vitamin D supplementation.

Conclusions:

• Vitamin D supplementation shows potential benefits for individuals with mild cognitive impairment.
• The lack of observed benefit in VEAD patients may indicate a more advanced disease stage or distinct pathological characteristics.
• Further research is warranted to explore vitamin D's role in neurodegenerative disease progression.