Type 2 diabetes mellitus is associated with differential effects on plasma cholesteryl ester transfer protein and phospholipid transfer protein activities and concentrations.
BACKGROUND
Human plasma contains two lipid transfer proteins, cholesteryl ester transfer protein (CETP) and phospholipid transfer protein (PLTP), which are crucial in reverse cholesterol transport.


METHODS
Plasma CETP and PLTP activity levels and concentrations in 16 type 2 diabetic patients and 16 matched healthy subjects were determined, and these data were correlated to clinical variables, including insulin sensitivity and lipid levels.


RESULTS
Plasma triglycerides were higher (p<0.02) and high-density lipoprotein (HDL) cholesterol (p<0.02) was lower in diabetic patients. Plasma CETP activity and concentrations were not significantly different between diabetic and healthy subjects, but CETP specific activity was lower in diabetic patients (p<0.001). Multiple regression analysis showed that plasma CETP activity was positively related to CETP concentration (p=0.0001) and negatively to the diabetic state (p<0.002) or to HbA1c (p<0.02). PLTP activity (p<0.05) and specific activity were higher (p<0.05), whereas there was no difference in PLTP concentration between the two groups. There was no significant bivariate correlation between PLTP concentration and activity, in either healthy or diabetic subjects. Multiple regression analysis did disclose positive relationships of PLTP activity with PLTP concentration (p=0.0001), plasma triglycerides (p=0.0001) and waist/hip ratio (p=0.0001), but not with the diabetic state or HbA1c.


CONCLUSIONS
Neither CETP nor PLTP activity was independently associated with insulin sensitivity. Specific CETP activity is decreased in type 2 diabetes mellitus. In contrast, specific PLTP activity is higher in diabetes, as a result of the association of plasma PLTP activity with plasma triglycerides and obesity. Measurement of both plasma lipid transfer protein activity and mass levels may thus provide extra information in diabetes mellitus.
Dullaart
R P F
RP
Department of Endocrinology, State University Hospital, Groningen, The Netherlands. r.p.f.dullaart@int.azg.nl
De Vries
R
R
Scheek
L
L
Borggreve
S E
SE
Van Gent
T
T
Dallinga-Thie
G M
GM
Ito
M
M
Nagano
M
M
Sluiter
W J
WJ
Hattori
H
H
Van Tol
A
A
D001053:Apolipoproteins / Q000097:blood; D001786:Blood Glucose / Q000032:analysis; D001823:Body Composition; D015992:Body Mass Index; D002352:Carrier Proteins / Q000097:blood*; D002784:Cholesterol / Q000097:blood; D053480:Cholesterol Ester Transfer Proteins; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D015309:Glucose Clamp Technique; D006442:Glycated Hemoglobin / Q000032:analysis; D006023:Glycoproteins / Q000097:blood*; D006801:Humans; D007328:Insulin / Q000097:blood; D008074:Lipoproteins / Q000097:blood; D008565:Membrane Proteins / Q000097:blood*; D008875:Middle Aged; D049294:Phospholipid Transfer Proteins / Q000097:blood*; D012044:Regression Analysis; D018709:Statistics, Nonparametric; D014280:Triglycerides / Q000097:blood; D049629:Waist-Hip Ratio
D001053:Apolipoproteins; D001786:Blood Glucose; D002352:Carrier Proteins; D002784:Cholesterol; D053480:Cholesterol Ester Transfer Proteins; D006442:Glycated Hemoglobin; D006023:Glycoproteins; D007328:Insulin; D008074:Lipoproteins; D008565:Membrane Proteins; D049294:Phospholipid Transfer Proteins; D014280:Triglycerides; C506642:CETP protein, human; C030104:lipoprotein cholesterol