Editorials |
From the Université Pierre et Marie Curie - Paris 6 (A.K., M.J.C.), UMR S551 "Dyslipoproteinemia and Atherosclerosis", Paris, France; INSERM, UMR S551 (A.K., M.J.C.), Paris France; and AP-HP (A.K., M.J.C.), Groupe hospitalier Pitié - Salpétrière, Paris France.
Correspondence to Anatol Kontush, INSERM, UMR S551, F-75013 Paris France. E-mail kontush@chups.jussieu.fr
An extract of the first 250 words of the full text is provided, because this article has no abstract. |
The last decade has witnessed an explosion in studies of the role of lipoproteins in brain function. Neurons require a continuous supply of lipids for membrane synthesis and acetylcholine production. Indeed, the brain is a site of intense lipid turnover—even though the central nervous system (CNS) accounts for only 2.1% of body weight, it contains 23% of total body cholesterol.1 Lipid metabolism in the brain is tightly controlled locally, as plasma lipoproteins are shielded from the brain by the blood-brain barrier. Although neuronal cells are capable of de novo synthesis of a wide spectrum of molecular species of lipids, they rely heavily on exogenous sources and readily bind and internalize lipoproteins of the extracellular fluid.2 Equally, neurons need to dispose of excess lipids; lipoprotein-mediated lipid transport is therefore bidirectional and includes cellular efflux of cholesterol.3
See accompanying article on page 1556
Human cerebrospinal fluid (CSF) primarily contains spherical lipoproteins of approximately 10 to 12 nm in diameter with hydrated density in the range 1.063 to 1.25 g/mL, thereby resembling HDL in human plasma.3,4 Lipid concentrations in CSF are however much lower (eg, 300- to 400-fold for total cholesterol and phospholipids) as compared to the plasma compartment.4 Apolipoproteins (apo) E and A-I are the major apolipoproteins in human CSF (typical concentration range: 0.1 to 0.4 mg/dL3,4), with apoA-II, A-IV, J, D, C-II, C-III, C-IV, and H equally present.3,4 Importantly, CSF lipoproteins carry amyloid-β (Aβ), a 39- to 43-aa peptide produced in neuronal cells, which is the major component of senile
Related Article:
Arterioscler Thromb Vasc Biol 2008 28: 1556-1562.
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