Relation between retinol, retinol-binding protein 4, transthyretin and carotid intima media thickness.
OBJECTIVE
Retinol is transported in a complex with retinol-binding protein 4 (RBP4) and transthyretin (TTR) in the circulation. While retinol is associated with various cardiovascular risk factors, the relation between retinol, RBP4, TTR and carotid intima media thickness (IMT) has not been analysed yet.


METHODS
Retinol, RBP4 and TTR were measured in 96 individuals and their relation to mean and maximal IMT was determined.


RESULTS
Mean IMT correlated with RBP4 (r=0.335, p<0.001), retinol (r=-0.241, p=0.043), RBP/TTR ratio (r=0.254, p=0.025) and retinol/RBP4 ratio (r=-0.549, p<0.001). Adjustment for age, sex, BMI, blood pressure, HDL/total cholesterol ratio, triglyceride, diabetes and smoking revealed that the retinol/RBP4 ratio was strongly and independently associated with mean IMT. Similar results were found for maximal IMT, which included the measurement of plaques.


CONCLUSIONS
The data support that the transport complex of vitamin A is associated with the IMT, an established parameter of atherosclerosis. Changes in RBP4 saturation with retinol may link renal dysfunction and insulin resistance to atherosclerosis.
Bobbert
Thomas
T
Department of Endocrinology, Diabetes and Nutrition, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany.
Raila
Jens
J
Schwarz
Franziska
F
Mai
Knut
K
Henze
Andrea
A
Pfeiffer
Andreas F H
AF
Schweigert
Florian J
FJ
Spranger
Joachim
J
D017536:Carotid Artery, Common / Q000000981:diagnostic imaging / Q000473:pathology*; D003920:Diabetes Mellitus / Q000097:blood / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011228:Prealbumin / Q000378:metabolism*; D054839:Retinol-Binding Proteins, Plasma / Q000378:metabolism*; D017539:Tunica Intima / Q000000981:diagnostic imaging / Q000473:pathology*; D017540:Tunica Media / Q000000981:diagnostic imaging / Q000473:pathology*; D014463:Ultrasonography; D014801:Vitamin A / Q000097:blood*
D011228:Prealbumin; C101326:RBP4 protein, human; D054839:Retinol-Binding Proteins, Plasma; D014801:Vitamin A