Retinol-binding protein 4 is associated with components of the metabolic syndrome, but not with insulin resistance, in men with type 2 diabetes or coronary artery disease.

Abstract

AIMS/HYPOTHESIS:

Retinol-binding protein 4 (RBP4) has recently been reported to be associated with insulin resistance and the metabolic syndrome. This study tested the hypothesis that RBP4 is a marker of insulin resistance and the metabolic syndrome in patients with type 2 diabetes or coronary artery disease (CAD) or in non-diabetic control subjects without CAD.

METHODS:

Serum RBP4 was measured in 365 men (126 with type 2 diabetes, 143 with CAD and 96 control subjects) and correlated with the homeostasis model assessment of insulin resistance index (HOMA-IR), components of the metabolic syndrome and lipoprotein metabolism. RBP4 was detected by ELISA and validated by quantitative Western blotting.

RESULTS:

RBP4 concentrations detected by ELISA were shown to be strongly associated with the results gained in quantitative Western blots. There were no associations of RBP4 with HOMA-IR or HbA(1c) in any of the groups studied. In patients with type 2 diabetes there were significant positive correlations of RBP4 with total cholesterol, LDL-cholesterol, VLDL-cholesterol, plasma triacylglycerol and hepatic lipase activity. In patients with CAD, there were significant associations of RBP4 with VLDL-cholesterol, plasma triacylglycerol and hepatic lipase activity, while non-diabetic control subjects without CAD showed positive correlations of RBP4 with VLDL-cholesterol and plasma triacylglycerol.

CONCLUSIONS/INTERPRETATION:

RBP4 does not seem to be a valuable marker for identification of the metabolic syndrome or insulin resistance in male patients with type 2 diabetes or CAD. Independent associations of RBP4 with pro-atherogenic lipoproteins and enzymes of lipoprotein metabolism indicate a possible role of RBP4 in lipid metabolism.

• Authors: M von Eynatten, P M Lepper, D Liu, K Lang, M Baumann, P P Nawroth, A Bierhaus, K A Dugi, U Heemann, B Allolio, P M Humpert
• Journal: Diabetologia (Diabetologia) Vol. 50 Issue 9 Pg. 1930-1937 (Sep 2007) ISSN: 0012-186X [Print] Germany
• PMID: 17639305 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Adiponectin
• Insulin
• Lipoproteins
• RBP4 protein, human
• Retinol-Binding Proteins, Plasma

Topics

• Adiponectin (blood)
• Aged
• Blotting, Western
• Coronary Disease (blood)
• Diabetes Mellitus, Type 2 (blood)
• Diabetic Angiopathies (blood)
• Humans
• Insulin (blood)
• Lipoproteins (blood)
• Male
• Metabolic Syndrome (blood)
• Middle Aged
• Reference Values
• Retinol-Binding Proteins, Plasma (metabolism)