Plasma lipoprotein distribution of apoC-III in normolipidemic and hypertriglyceridemic subjects: comparison of the apoC-III to apoE ratio in different lipoprotein fractions.
In order to assess the relationship between plasma accumulation of triglyceride-rich lipoproteins (TRL) and lipoprotein levels of apoC-III and apoE, we have measured apoC-III and apoE in lipoproteins separated according to size (by automated gel filtration chromatography) from plasma of normolipidemic subjects (plasma triglyceride (TG): 0.84 +/- 0.10 mmol/l; mean +/- SE, n = 8), and from type III (n = 8) and type IV (n = 8) hyperlipoproteinemic patients, matched for plasma TG (5.76 +/- 0.62 v 5.55 +/- 0.45 mmol/l, resp.). Total plasma apoC-III concentration was similar in type III and type IV patients (33.1 +/- 3.4 v 37.6 +/- 4.4 mg/dl, respectively), but was significantly increased compared to normolipidemic controls (10.0 +/- 1.0 mg/dl, P < 0.001). TRL apoC-III was lower and high density lipoprotein (HDL) apoC-III was significantly higher in type III versus type IV subjects (14.8 +/- 3.2 vs. 22.8 +/- 3.0 mg/dl, P < 0.05; 8.3 +/- 1.0 vs. 5.2 +/- 0.5 mg/dl, P < 0.05). Plasma concentration of apoC-III in lipoproteins that eluted between TRL and HDL (intermediate-sized lipoproteins, ISL) was similar in the two hypertriglyceridemic groups (10.1 +/- 1.3 vs. 9.7 +/- 1.6 mg/dl), but was significantly higher (P< 0.05) than controls (2.2 +/- 0.3 mg/dl). TRL, ISL, and HDL apoE concentrations were significantly higher in type III versus type IV subjects (P < 0.05). All lipoprotein fractions in type III patients were characterized by lower apoC-III to apoE ratios. In contrast, the TRL apoC-III to apoE ratio of type IV patients was similar and the ISL apoC-III to apoE ratio was significantly higher, compared to normolipidemic individuals. These results indicate that compared to normolipidemic individuals, remnant-like lipoproteins in the ISL fraction of type IV patients are enriched in apoC-III relative to apoE, whereas those of type III patients are enriched in apoE relative to apoC-III.
Fredenrich
A
A
Hyperlipidemia and Atherosclerosis Research Group, Clinical Research Institute of Montreal, Quebec, Canada.
Giroux
L M
LM
Tremblay
M
M
Krimbou
L
L
Davignon
J
J
Cohn
J S
JS
D000328:Adult; D053305:Apolipoprotein C-III; D001056:Apolipoproteins C / Q000097:blood*; D001057:Apolipoproteins E / Q000097:blood*; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D015228:Hypertriglyceridemia / Q000097:blood*; D008074:Lipoproteins / Q000097:blood*; D008075:Lipoproteins, HDL / Q000097:blood; D008077:Lipoproteins, LDL / Q000097:blood; D008297:Male; D012016:Reference Values; D014280:Triglycerides / Q000097:blood
D053305:Apolipoprotein C-III; D001056:Apolipoproteins C; D001057:Apolipoproteins E; D008074:Lipoproteins; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D014280:Triglycerides