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Finally, cholesterol efflux from rat astrocytes by human CSF lipoproteins was correlated with the CSF (apo)lipoprotein content.Completely free Essex dating site - free messaging, chat, who viewed you. Dating in Southend-on-Sea, Colchester, Chelmsford, Basildon, Harlow, and Grays.
Characterization and functional studies of lipoproteins, lipid transfer proteins, and lecithin:cholesterol acyltransferase in CSF of normal individuals and patients with Alzheimer's disease.Enzymatically active LCAT was present in human CSF as well as PLTP activity and mass; no CETP mass was detected. On the contrary, increasing cellular cholesterol concentrations by adding β-VLDL to Cos1 cells causes a decrease of the secretion of the soluble form of APP (s APP).In CSF from AD patients, LCAT activity was 50% lower than in CSF from normal controls. These observations suggest that CSF lipoproteins may fulfill an important role in maintaining the neuronal cholesterol levels, thereby regulating indirectly the production of amyloidogenic peptides.Other reports show that a reduction in brain tissue membrane lipids (gangliosides, phospholipids, and cholesterol) is correlated with reduced synaptic function in patients with early onset form (EOAD) Alzheimer's disease, independent of the β amyloid depositions (17).Apo E and apo A-I are the major CSF apolipoproteins, which are present in high density lipoproteins (HDL), while apo B-containing very low or low density lipoproteins (VLDL or LDL) were never identified in CSF. (4) and later reports by Borghini et al (10) suggest that apo E-enriched HDL is the predominant lipoprotein in CSF.We investigated the lipoprotein distribution and composition in cerebrospinal fluid (CSF) in a group of patients with Alzheimer's disease (AD) or affected by other types of dementia in comparison to non-demented controls. In analogy with the metabolism of lipids in the peripheral circulation, cerebrospinal fluid (CSF) lipids are transported by lipoproteins.We found slightly decreased apolipoprotein (apo)E and cholesterol concentrations in CSF of AD patients and moderately increased apo A-I concentrations, while in patients suffering from other types of dementia the apo A-I CSF concentration was increased. Although several reports describe the composition of CSF lipoproteins (4, 8–12), their detailed structure and functions are only poorly understood.In order to understand how the HDL particles in the brain compartment are synthesized and remodeled, we investigated in human CSF the presence of minor lipoprotein subclasses such as preβ particles by bi-dimensional non-denaturing gel electrophoresis.The physiological role of CSF lipoproteins as substrates for lipolytic enzymes such as lecithin:cholesterol acyltransferase (LCAT), and for lipid transfer proteins such as cholesteryl ester transfer protein (CETP) and phospholipid transfer protein (PLTP) was investigated.Bi-dimensional analysis demonstrated pre-β and α apo A-I-containing particles; apo E and apo A-II were detected only in α-migrating particles. Such active lipid redistribution might prove to be functionally important because several recent studies have shown that the neuronal membrane cholesterol content influences processing of the amyloid precursor protein (APP) (13–15).Apo A-IV distributed both to pre-β and γ-migrating particles; the LCAT signal was co-localized in this γ-migrating fraction. Decreasing the neuronal cell cholesterol content, by combining a treatment with lovastatin (HMG-Co A reductase inhibitor) and α-methyl-β-cyclodextrin, reduces amyloid β production.