We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Retinol Binding Protein 4 Expression in Humans: Relationship to Insulin Resistance, Inflammation, and Response to Pioglitazone.
- Authors
Aiwei Yao-Borengasser; Varma, Vijayalakshmi; Bodles, Angela M.; Rasouli, Neda; Phanavanh, Bounleut; Lee, Mijeong; Starks, Tasha; Kern, Leslie M.; Spencer, Horace J.; Rashidi, Amir A.; Mcgehee, Robert E.; Fried, Susan K.; Kern, Philip A.
- Abstract
Retinol binding protein 4 (RBP4) was overexpressed in adipose tissue of Glut4 KO mice, and elevated RBP4 has been associated with insulin resistance in mouse and human studies. To determine the relationship between RBP4 and obesity, insulin resistance, and other markers of insulin resistance in humans, RBP4 gene expression measured by real-time RT-PCR and blood levels measured by ELISA and Western blotting were studied in adipose tissue and muscle of 85 non-diabetic humans over a wide range of BMI (19-55 Kg/m²) and S[sub I] (1.02-26.77 x 10[sup -5] x min[sup -1]/pM), and RBP4 expression was also measured from visceral (VAT) and subcutaneous adipose tissue (SAT) from 16 surgical patients. RBP4 expression was 3-fold higher in SAT vs VAT (p<0.005), and RBP4 was 7-fold higher in the adipocyte (vs stromal) fraction, and undetectable in preadipocytes. Neither SAT RBP4 expression nor blood RBP4 level showed a significant relationship with BMI or S[sub I]. However, there was a strong positive correlation between RBP4 mRNA and the inflammation markers MCP1 (r=0.42, p<0.0001) and CD68 (r=0.46, p<0.0001)). Adipose GLUT4 mRNA was also highly associated with RBP4 (r=0.53, p<0.0001). These relationships remained significant after adjustment for BMI and St. Impaired glucose tolerant subjects were treated with pioglitazone, resulting in an increase in S[sub 1] along with a 60% increase in RBP4 expression, but no change in plasma RBP4. The in vitro treatment of cultured adipocytes with pioglitazone yielded a similar increase in RBP4 mRNA. Hence, RBP4 expression in humans was not significantly associated with obesity or insulin resistance, and actually increased with TZD treatment. However, RBP4 was associated with inflammatory markers and GLUT 4 expression, suggesting a complex role in metabolic syndrome.
- Subjects
VITAMIN A; CARRIER proteins; GENE expression; INSULIN resistance; ADIPOSE tissues; FAT cells; OBESITY; METABOLIC syndrome
- Publication
Diabetes, 2007, Vol 56, pA361
- ISSN
0012-1797
- Publication type
Article