Modulatory effect of grape-seed procyanidins on local and systemic inflammation in diet-induced obesity rats

Chronic low-grade inflammation in obesity is characterized by macrophage accumulation in white adipose tissue (WAT) and abnormal cytokine production. We tested the hypothesis that grape-seed procyanidin extract (PE), with known anti-inflammatory and antioxidant effects, would improve local and systemic inflammation in diet-induced obesity rats. First, we analyzed the preventive effects of procyanidins (30 mg/kg per day) on rats fed a 60% kcal fat diet for 19 weeks. Second, we induced cafeteria diet obesity for 13 weeks to investigate the corrective effects of two PE doses (25 and 50 mg/kg per day) for 10 and 30 days. In the preventive model, PE group had reduced not only body weight but also plasmatic systemic markers of inflammation tumor necrosis factor-α (TNF-α) and C-reactive protein (CRP). The PE preventive treatment significantly showed an increased adiponectin expression and decreased TNF-α, interleukin-6 and CRP expression in mesenteric WAT and muscle TNF-α. A reduced NF-κB activity in liver is also observed which can be related to low expression rates of hepatic inflammatory markers found in PE group. Finally, PE dietary supplementation is linked to a reduced expression of Emr1 (specific marker of macrophage F4/80), which suggests a reduced macrophage infiltration of WAT. In the corrective model, however, only the high dose of PE reduced CRP plasma levels in the short treatment without changes in plasmatic TNF-α. In conclusion, orally ingested PE helps preventing imbalanced obesity cytokine pattern, but its corrective effects need to be further investigated. The dietary regular intake of food or drinks containing procyanidins might help prevent low-grade inflammatory-related diseases.