Lipoprotein Metabolism in APOB L343V Familial Hypobetalipoproteinemia.

Amanda Hooper, L. Heeks, Kenneth Robertson, Danie Champain, J. Hua, S. Song, P. Parhofer, Hugh Barrett, Frank Van Bockxmeer, John Burnett

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    Abstract

    Context: Familial hypobetalipoproteinemia (FHBL) is a codominant disorder of lipoprotein metabolism characterized by decreased plasma concentrations of low-density lipoprotein (LDL)-cholesterol and apolipoprotein B (apoB). Objective: The objective was to examine the effect of heterozygous APOB L343V FHBL on postprandial triglyceride-rich lipoprotein (TRL) and fasting lipoprotein metabolism. Methods: Plasma incremental area under the curve apoB-48 and apoB-48 kinetics were determined after ingestion of a standardized oral fat load using compartmental modeling. Very low-density lipoprotein (VLDL)-, intermediate-density lipoprotein (IDL)-, and LDL-apoB kinetics were determined in the fasting state using stable isotope methods and compartmental modeling. Results: The postprandial incremental area under the curve (0–10 h) in FHBL subjects (n = 3) was lower for large TRL-triglyceride (−77%; P < .0001), small TRL-cholesterol (−83%; P < .001), small TRL-triglyceride (−88%; P < .001), and for plasma triglyceride (−70%; P < .01) and apoB (−63%; P < .0001) compared with controls. Compartmental analysis showed that apoB-48 production was lower (−91%; P < .05) compared with controls. VLDL-apoB concentrations in FHBL subjects (n = 2) were lower by more than 75% compared with healthy, normolipidemic control subjects (P < .01). The VLDL-apoB fractional catabolic rate (FCR) was more than 5-fold higher in the FHBL subjects (P = .07). ApoB production rates and IDL- and LDL-apoB FCRs were not different between FHBL subjects and controls. Conclusions: We conclude that when compared to controls, APOB L343V FHBL heterozygotes show lower TRL production with normal postprandial TRL particle clearance. In contrast, VLDL-apoB production was normal, whereas the FCR was higher in heterozygotes compared with lean control subjects. These mechanisms account for the marked hypolipidemic state observed in these FHBL subjects. - See more at: http://press.endocrine.org/doi/abs/10.1210/jc.2015-2731#sthash.roa6afj8.dpuf
    Original languageEnglish
    Pages (from-to)E1484-E1490
    Number of pages7
    JournalJournal of Clinical Endocrinology and Metabolism
    Volume100
    Issue number11
    Early online date31 Aug 2015
    DOIs
    Publication statusPublished - Nov 2015

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