Apolipoprotein (apo) E and the two B apolipoproteins, apoB48 and apoB100, are important proteins in human lipoprotein metabolism. Commonly occurring polymorphisms in the genes for apoE and apoB result in amino acid substitutions that produce readily detectable phenotypic differences in these proteins. We studied changes in apoE and apoB phenotypes before and after liver transplantation to gain new insights into apolipoprotein physiology. In all 29 patients that we studied, the postoperative serum apoE phenotype of the recipient, as assessed by isoelectric focusing, converted virtually completely to that of the donor, providing evidence that greater than 90% of the apoE in the plasma is synthesized by the liver. In contrast, the cerebrospinal fluid apoE phenotype did not change to the donor's phenotype after liver transplantation, indicating that most of the apoE in CSF cannot be derived from the plasma pool and therefore must be synthesized locally. The apoB100 phenotype (assessed with immunoassays using monoclonal antibody MB19, an antibody that detects a two-allele polymorphism in apoB) invariably converted to the phenotype of the donor. In four normolipidemic patients, we determined the MB19 phenotype of both the apoB100 and apoB48 in the "chylomicron fraction" isolated from plasma 3 h after a fat-rich meal. Interestingly, the apoB100 in the chylomicron fraction invariably had the phenotype of the donor, indicating that the vast majority of the large, triglyceride-rich apoB100-containing lipoproteins that appear in the plasma after a fat-rich meal are actually VLDL of hepatic origin. The MB19 phenotype of the apoB48 in the plasma chylomicron fraction did not change after liver transplantation, indicating that almost all of the apoB48 in plasma chylomicrons is derived from the intestine. These results were consistent with our immunocytochemical studies on intestinal biopsy specimens of organ donors; using apoB-specific monoclonal antibodies, we found evidence for apoB48, but not apoB100, in donor intestinal biopsy specimens.
M F Linton, R Gish, S T Hubl, E Bütler, C Esquivel, W I Bry, J K Boyles, M R Wardell, S G Young
Title and authors | Publication | Year |
---|---|---|
HDL and cognition in neurodegenerative disorders
DA Hottman, D Chernick, S Cheng, Z Wang, L Li |
Neurobiology of Disease | 2014 |
Syndecan 4 Is Involved in Mediating HCV Entry through Interaction with Lipoviral Particle-Associated Apolipoprotein E
M Lefèvre, DJ Felmlee, M Parnot, TF Baumert, C Schuster |
PloS one | 2014 |
ApoE4 delays dendritic spine formation during neuron development and accelerates loss of mature spines in vitro
E Nwabuisi‑Heath, GW Rebeck, MJ LaDu, C Yu |
ASN NEURO | 2014 |
ApoA-I/HDL Generation and Intracellular Cholesterol Transport through Cytosolic Lipid-Protein Particles in Astrocytes
J Ito, M Michikawa |
Journal of Lipids | 2014 |
Macrophage-derived apoESendai suppresses atherosclerosis while causing lipoprotein glomerulopathy in hyperlipidemic mice
H Tavori, D Fan, I Giunzioni, L Zhu, MF Linton, AB Fogo, S Fazio |
Journal of lipid research | 2014 |
Development and partial characterisation of an antiserum against apolipoprotein B of the short-finned eel, Anguilla australis
EL Damsteegt, H Mizuta, Y Ozaki, N Hiramatsu, T Todo, A Hara, S Ijiri, S Adachi, PM Lokman |
Journal of Comparative Physiology B | 2014 |
Total apolipoprotein E levels and specific isoform composition in cerebrospinal fluid and plasma from Alzheimer’s disease patients and controls
E Martínez-Morillo, O Hansson, Y Atagi, G Bu, L Minthon, EP Diamandis, HM Nielsen |
Acta Neuropathologica | 2014 |
High-Density Lipoproteins and Cerebrovascular Integrity in Alzheimer’s Disease
S Stukas, J Robert, CL Wellington |
Cell Metabolism | 2014 |
Increasing cellular level of phosphatidic acid enhances FGF-1 production in long term-cultured rat astrocytes
Y Nagayasu, S Morita, H Hayashi, Y Miura, K Yokoyama, M Michikawa, J Ito |
Brain Research | 2014 |
Astrocyte׳s endogenous apoE generates HDL-like lipoproteins using previously synthesized cholesterol through interaction with ABCA1
J Ito, Y Nagayasu, Y Miura, S Yokoyama, M Michikawa |
Brain Research | 2014 |
HDL and cholesterol handling in the brain
C Vitali, CL Wellington, L Calabresi |
Cardiovascular Research | 2014 |
Syndecan 4 Is Involved in Mediating HCV Entry through Interaction with Lipoviral Particle-Associated Apolipoprotein E
M Lefèvre, DJ Felmlee, M Parnot, TF Baumert, C Schuster, R Ray |
PloS one | 2014 |