Metabolism of chylomicrons in subjects with dysbetalipoproteinaemia (type III hyperlipoproteinaemia).
These studies were conducted to investigate whether subjects with dysbetalipoproteinaemia (type III hyperlipoproteinaemia) can catabolize chylomicrons normally and if chylomicron catabolism is related to the triglyceride pool size. Iodinated postprandial plasma chylomicrons were injected into subjects with dysbetalipoproteinaemia (n = 7), subjects with endogenous hypertriglyceridaemia (n = 4), and normal subjects (n = 5). The subjects with dysbetalipoproteinaemia had VLDL-cholesterol/total triglyceride ratios greater than 0.35 and were deficient in isoapoE-3 and isoapoE-4. The decay of radioactivity in chylomicron apoB was measured and residence times (RT) were calculated by measuring the area under the radioactivity decay curve. The mean RT for chylomicron apoB in subjects with dysbetalipoproteinaemia was 17.4 +/- 3.5 h, which was significantly longer than in both subjects with endogenous hypertriglyceridaemia (4.8 +/- 2.1 h) and also in normal subjects (5.9 +/- 1.6 h). There was no significant correlation between chylomicron apoB RT and triglyceride levels in subjects with dysbetalipoproteinaemia or in other subjects. Thus, chylomicron apoB catabolism is retarded in subjects with dysbetalipoproteinaemia. The slow removal of chylomicron apoB in subjects with dysbetalipoproteinaemia does not seem to be attributable to an increased triglyceride pool size.
Haffner
S M
SM
Department of Medicine, Harborview Medical Center, University of Washington, Seattle.
Kushwaha
R S
RS
Hazzard
W R
WR
D000328:Adult; D000368:Aged; D001055:Apolipoproteins B / Q000097:blood; D001057:Apolipoproteins E / Q000097:blood; D002914:Chylomicrons / Q000097:blood*; D005260:Female; D006801:Humans; D006952:Hyperlipoproteinemia Type III / Q000097:blood*; D015228:Hypertriglyceridemia / Q000097:blood; D007700:Kinetics; D008074:Lipoproteins / Q000097:blood; D053419:Lipoproteins, IDL; D008077:Lipoproteins, LDL / Q000097:blood; D008079:Lipoproteins, VLDL / Q000097:blood; D008297:Male; D008875:Middle Aged; D014280:Triglycerides / Q000097:blood
D001055:Apolipoproteins B; D001057:Apolipoproteins E; D002914:Chylomicrons; D008074:Lipoproteins; D053419:Lipoproteins, IDL; D008077:Lipoproteins, LDL; D008079:Lipoproteins, VLDL; D014280:Triglycerides