Conclusion
PCA restores the insulin responsiveness of OB-VAT by increasing IRS-1 and Akt phosphorylation which could be related with the lower PTP1B activity found in PCA-treated OB-VAT. Furthermore, PCA diminishes inflammation in VAT. These results support the beneficial role of an anthocyanin-rich diet against inflammation and insulin resistance in obesity.
Methods
VATs obtained from NW and OB subjects were incubated or not (control) with 100 μM PCA for 24 h. After incubation, tissues untreated and treated with PCA were acutely stimulated with insulin (20 nM, 20 min). PTP1B, p65 NF-κB, phospho-p65 NF-κB, IRS-1, IRβ, Akt, GLUT4 as well as basal and insulin-stimulated Tyr-IRS-1 and Ser-Akt phosphorylations were assessed by Western blotting in NW- and OB-VAT. Samples were assessed for PTP1B activity and adipocytokine secretion.
Results
PCA restored insulin-induced phosphorylation in OB-VAT by increasing phospho-Tyr-IRS-1 and phospho-Ser-Akt after insulin stimulation as observed in NW-VAT (p < 0.05). PTP1B activity was lower in OB-VAT treated with PCA with respect to untreated (p < 0.05). Compared to non-treated tissues, PCA reduced phospho-p65 NF-κB and IL-6 in OB-VAT, and IL-1β in NW-VAT (p < 0.05); and increased adiponectin secretion in NW-VAT (p < 0.05).