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Metabolism of apoB-100-containing lipoproteins in familial hyperchylomicronemia.
J Lipid Res. 1993 Jan; 34(1):147-56.JL

Abstract

The metabolism of apolipoprotein B-100 was studied in three patients with familial hyperchylomicronemia (type I hyperlipoproteinemia) using a very low density lipoprotein (VLDL) dual-tracer technique. Radioiodinated VLDL1 (Sf 60-400) and VLDL2 (Sf 20-60) were injected and their catabolism and rate of the transfer of apoB into VLDL2, intermediate density lipoprotein (IDL) (Sf 12-20), and low density lipoprotein (LDL) (Sf 0-12) were compared in patients and in five normolipidemic controls. The rates of delipidation of large triglyceride-rich VLDL1 to VLDL2 (0.26-0.54 pools/day vs. 2.5-5.2 pools/day in controls) and VLDL1 direct catabolism (0.33-0.92 pools/day vs. 4.2-14.7 pools/day in controls) were found to be significantly reduced in type I patients resulting in a tenfold increase of VLDL1 pool size. ApoB synthesis into this density interval was, however, normal as was that into smaller VLDL2. the circulating apoB mass in VLDL2 was not increased. In fact, apart from a modest decrease in the rate of VLDL2 delipidation to IDL and LDL, the behavior of apoB in this density interval was similar in hyperchylomicronemic and normal subjects. Likewise, the transfer of apoB through the IDL and LDL density ranges was not significantly different from normal. Pool sizes of these fractions, however, were reduced, the latter significantly (354-491 mg vs. 1,160-2,505 mg in controls) due to increased direct catabolism in hyperchylomicronemic patients. The results of this study indicate that lipoprotein lipase deficiency primarily affects VLDL1 metabolism, both its delipidation and direct removal from plasma. Lipolysis further down the delipidation cascade is not dependent on this enzyme. Hypercatabolism rather than a failure of synthesis of IDL and LDL was responsible for the decreased pools for both lipoproteins.

Authors+Show Affiliations

Institute of Biochemistry, Glasgow Royal Infirmary.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

8445339

Citation

Demant, T, et al. "Metabolism of apoB-100-containing Lipoproteins in Familial Hyperchylomicronemia." Journal of Lipid Research, vol. 34, no. 1, 1993, pp. 147-56.
Demant T, Gaw A, Watts GF, et al. Metabolism of apoB-100-containing lipoproteins in familial hyperchylomicronemia. J Lipid Res. 1993;34(1):147-56.
Demant, T., Gaw, A., Watts, G. F., Durrington, P., Buckley, B., Imrie, C. W., Wilson, C., Packard, C. J., & Shepherd, J. (1993). Metabolism of apoB-100-containing lipoproteins in familial hyperchylomicronemia. Journal of Lipid Research, 34(1), 147-56.
Demant T, et al. Metabolism of apoB-100-containing Lipoproteins in Familial Hyperchylomicronemia. J Lipid Res. 1993;34(1):147-56. PubMed PMID: 8445339.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Metabolism of apoB-100-containing lipoproteins in familial hyperchylomicronemia. AU - Demant,T, AU - Gaw,A, AU - Watts,G F, AU - Durrington,P, AU - Buckley,B, AU - Imrie,C W, AU - Wilson,C, AU - Packard,C J, AU - Shepherd,J, PY - 1993/1/1/pubmed PY - 1993/1/1/medline PY - 1993/1/1/entrez SP - 147 EP - 56 JF - Journal of lipid research JO - J Lipid Res VL - 34 IS - 1 N2 - The metabolism of apolipoprotein B-100 was studied in three patients with familial hyperchylomicronemia (type I hyperlipoproteinemia) using a very low density lipoprotein (VLDL) dual-tracer technique. Radioiodinated VLDL1 (Sf 60-400) and VLDL2 (Sf 20-60) were injected and their catabolism and rate of the transfer of apoB into VLDL2, intermediate density lipoprotein (IDL) (Sf 12-20), and low density lipoprotein (LDL) (Sf 0-12) were compared in patients and in five normolipidemic controls. The rates of delipidation of large triglyceride-rich VLDL1 to VLDL2 (0.26-0.54 pools/day vs. 2.5-5.2 pools/day in controls) and VLDL1 direct catabolism (0.33-0.92 pools/day vs. 4.2-14.7 pools/day in controls) were found to be significantly reduced in type I patients resulting in a tenfold increase of VLDL1 pool size. ApoB synthesis into this density interval was, however, normal as was that into smaller VLDL2. the circulating apoB mass in VLDL2 was not increased. In fact, apart from a modest decrease in the rate of VLDL2 delipidation to IDL and LDL, the behavior of apoB in this density interval was similar in hyperchylomicronemic and normal subjects. Likewise, the transfer of apoB through the IDL and LDL density ranges was not significantly different from normal. Pool sizes of these fractions, however, were reduced, the latter significantly (354-491 mg vs. 1,160-2,505 mg in controls) due to increased direct catabolism in hyperchylomicronemic patients. The results of this study indicate that lipoprotein lipase deficiency primarily affects VLDL1 metabolism, both its delipidation and direct removal from plasma. Lipolysis further down the delipidation cascade is not dependent on this enzyme. Hypercatabolism rather than a failure of synthesis of IDL and LDL was responsible for the decreased pools for both lipoproteins. SN - 0022-2275 UR - https://www.unboundmedicine.com/medline/citation/8445339/Metabolism_of_apoB_100_containing_lipoproteins_in_familial_hyperchylomicronemia_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0022-2275(20)41328-8 DB - PRIME DP - Unbound Medicine ER -