Apolipoprotein B metabolism in subjects with deficiency of apolipoproteins CIII and AI. Evidence that apolipoprotein CIII inhibits catabolism of triglyceride-rich lipoproteins by lipoprotein lipase in vivo.
Why the study?
Does apolipoprotein CIII inhibit the catabolism of triglyceride-rich lipoproteins by lipoprotein lipase in vivo?
Population
Two sisters with apo CIII-apo AI deficiency, characterized by reduced VLDL triglyceride, normal LDL…
Comparison
In vivo compartmental analysis of apo B… vs Normal subjects/sera.
Design
Case_series
Authors
Discussion
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Member takes
Implication
Apo CIII may inhibit LPL-mediated catabolism in hypertriglyceridemia; case report leaves open broader therapeutic relevance.
Key Points
- The study aims to investigate the metabolism of apolipoprotein B in individuals with apolipoprotein CIII-apo AI deficiency.
- Analyzed VLDL, IDL, and LDL metabolism in two sisters with apo CIII-apo AI deficiency.
- Performed compartmental analysis using 125I-VLDL and 131I-LDL injections to study kinetics of apo B metabolism.
- Conducted in vitro experiments assessing lipoprotein lipase activation with deficient serum.
- Fractional catabolic rates for VLDL apo B were 6-7 times faster than normal.
- VLDL triglyceride catabolism was rapid, converting to IDL and LDL efficiently.
- Purified apo CIII reduced LPL activity by 20-50% compared to the deficient sera.
Structured PICO
Does apolipoprotein CIII inhibit the catabolism of triglyceride-rich lipoproteins by lipoprotein lipase in vivo?
P
Population
Two sisters with apo CIII-apo AI deficiency, characterized by reduced VLDL triglyceride, normal LDL cholesterol, and near absence of HDL cholesterol.
I
Intervention
In vivo compartmental analysis of apo B metabolism after injection of 125I-VLDL, 131I-LDL, and [3H]glycerol; in vitro addition of purified apo CIII to deficient sera.
C
Comparator
Normal subjects/sera (for reference FCR values and in vitro comparisons).
O
Outcome
Fractional catabolic rates (FCR) for VLDL apo B and LDL apo B, and in vitro lipoprotein lipase (LPL) activity.surrogate
This study provides in vivo and in vitro evidence that apolipoprotein CIII inhibits the catabolism of triglyceride-rich lipoproteins by lipoprotein lipase.
Cite This Study
Ginsberg et al. (1986) studied this question.