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Cholesterol Efflux Assay
Published on: March 6, 2012
Cholesterol metabolism in the brain
1Department of Internal Medicine, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-8887, USA. john.dietschy@utsouthwestern.edu
Current Opinion in Lipidology
|March 27, 2001
Summary
The brain has a unique cholesterol system, primarily synthesized within and recycled among cells. Altered cholesterol balance impacts brain health and neurodegenerative diseases.
Area of Science:
- Neuroscience
- Biochemistry
- Cell Biology
Background:
- The central nervous system (CNS) contains a significant portion of the body's unesterified cholesterol, concentrated in glial cells, neurons, and myelin.
- Cholesterol turnover in the CNS is relatively slow compared to the whole body, with synthesis being the primary source and limited plasma transfer.
Purpose of the Study:
- To investigate cholesterol metabolism and turnover within the central nervous system.
- To understand the role of cholesterol in neurodegenerative disorders and brain repair processes.
Main Methods:
- Analysis of cholesterol pools in plasma membranes of glial cells and neurons, and in myelin.
- Quantification of daily cholesterol turnover rates in the brain.
- Examination of cholesterol output via 24S-hydroxycholesterol excretion.
- Investigation of potential involvement of apolipoproteins and membrane transport proteins in internal sterol recycling.
Main Results:
- Daily cholesterol turnover in the brain is a small fraction of total brain cholesterol, but its flux is significant relative to body-wide turnover.
- Cholesterol input is mainly from endogenous synthesis, with minimal net transfer from plasma.
- Cholesterol turnover is elevated in neurodegenerative conditions like Alzheimer's disease and Niemann-Pick type C disease.
- Evidence suggests substantial internal cholesterol recycling among CNS cells during development and repair, potentially involving apolipoprotein E and LDL receptor family members.
Conclusions:
- Cholesterol homeostasis in the CNS is maintained by a balance of synthesis, limited influx, and regulated output, with significant internal recycling.
- Disruptions in systemic cholesterol balance may influence CNS cholesterol recycling and apolipoprotein E expression, affecting neuronal and myelin integrity.
- Understanding CNS cholesterol dynamics is crucial for unraveling the mechanisms of neurodegenerative disorders and developing therapeutic strategies.
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