title: Relation between retinol, retinol-binding protein 4, transthyretin and carotid intima media thickness.
abstract: 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.
authors.affiliation: Department of Endocrinology, Diabetes and Nutrition, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bobbert
authors.forename: Jens
authors.initials: J
authors.lastname: Raila
authors.forename: Franziska
authors.initials: F
authors.lastname: Schwarz
authors.forename: Knut
authors.initials: K
authors.lastname: Mai
authors.forename: Andrea
authors.initials: A
authors.lastname: Henze
authors.forename: Andreas F H
authors.initials: AF
authors.lastname: Pfeiffer
authors.forename: Florian J
authors.initials: FJ
authors.lastname: Schweigert
authors.forename: Joachim
authors.initials: J
authors.lastname: Spranger
mesh_terms: 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*
chemical_list: D011228:Prealbumin; C101326:RBP4 protein, human; D054839:Retinol-Binding Proteins, Plasma; D014801:Vitamin A