Oxysterols and Oxysterol Sulfates in Alzheimer’s Disease Brain and Cerebrospinal Fluid

Irundika H.K. Dias*, Hala Shokr, Freya Shephard, Lisa Chakrabarti

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Background: Brain cholesterol levels are tightly regulated but increasing evidence indicates that cholesterol metabolism may drive Alzheimer’s disease (AD)-associated pathological changes. Recent advances in understanding of mitochondrial dysfunction in AD brain have presented a vital role played by mitochondria in oxysterol biosynthesis and their involvement in pathophysiology. Oxysterol accumulation in brain is controlled by various enzymatic pathways including sulfation. While research into oxysterol is under the areas of active investigation, there is less evidence for oxysterol sulfates levels in human brain. Objective: This study investigates the hypothesis that AD brain oxysterols detoxification via sulfation is impaired in later stages of disease resulting in oxysterol accumulation. Methods: Lipids were extracted from postmortem frozen brain tissue and cerebrospinal (CSF) from late- (Braak stage III-IV) and early- (Braak stage I-II) stage AD patients. Samples were spiked with internal standards prior to lipid extraction. Oxysterols were enriched with a two-step solid phase extraction using a polymeric SPE column and further separation was achieved by LC-MS/MS. Results: Oxysterols, 26-hydroxycholesterol (26-OHC), 25-hydroxycholesterol (25-OHC), and 7-oxycholesterol levels were higher in brain tissue and mitochondria extracted from late-stage AD brain tissue except for 24S-hydroxycholesterol, which was decreased in late AD. However, oxysterol sulfates are significantly lower in the AD frontal cortex. Oxysterols, 25-OHC, and 7-oxocholesterol was higher is CSF but 26-OHC and oxysterol sulfate levels were not changed. Conclusion: Our results show oxysterol metabolism is altered in AD brain mitochondria, favoring synthesis of 26-OHC, 25-OHC, and 7-oxocholesterol, and this may influence brain mitochondrial function and acceleration of the disease.
Original languageEnglish
Number of pages10
JournalJournal of Alzheimer's disease
Early online date27 Apr 2022
DOIs
Publication statusE-pub ahead of print - 27 Apr 2022

Bibliographical note

© 2022 – The authors. Published by IOS Press. This is an Open Access article distributed under the terms
of the Creative Commons Attribution-NonCommercial License (CC BY-NC 4.0).

Keywords

  • Psychiatry and Mental health
  • Geriatrics and Gerontology
  • Clinical Psychology
  • General Medicine
  • General Neuroscience

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