Wild-Blueberry Volatile and Phenolic Fractions Mitigate LPS-Induced Inflammatory Responses in Whole Blood of Children

Abstract

Abstract Objectives The anti-inflammatory effects of berries have been attributed to their polyphenol content. In vitro models of activated murine macrophages have shown that volatiles in berries exert anti-inflammatory effects as well. However, human data in this area are scarce. To address this limitation we measured the effects of wild-blueberry phenolic (WBB-P) and WBB volatile (WBB-V) fractions in LPS-treated whole blood (WB) of children. Methods Fasting WB was collected (n = 19), and treated with high and low doses of either WBB-P (2 μg/mL or 0.02 μg/mL), WBB-V (2 ng/mL or 0.02 ng/mL), or culture medium (RPMI) as control and incubated for 1 hour at 37°C. To evaluate potential anti-inflammatory effects of WBB molecules, lipopolysaccharide (LPS, 0.2 μg/mL or 1 μg/mL) was added to the wells, and samples incubated for 48 hours. Interleukin (IL)-1β, IL-6, IL-10 and TNF-α supernatant concentrations were measured using enzyme-linked immunosorbent assay. One-factor ANOVA analysis with participant ID as random effect was used to compare cytokine concentrations (ng/ml) of WBB fraction treatments against their respective RPMI + LPS controls. Results Children (12.0 ± 0.6 years old) were predominantly white (79%), and with a BMI percentile of 51 ± 35. At both LPS levels, IL-6 concentrations were lower in the high-dose WBB-P and WBB-V treatments compared to the control group. LPS-High: WBB-P: 22.2 ± 6.7 vs. RPMI: 28.2 ± 8.3 (p = 0.005); WBB-V: 24.4 ± 7.2 vs. RPMI: 28.2 ± 8.3 (p = 0.013). LPS-low: WBB-P: 20.4 ± 5.5 vs. RPMI: 26.6 ± 7.7 (p = 0.001); WBB-V: 20.6 ± 6.5 vs. RPMI: 26.6 ± 7.7 (p < 0.0001). At the lowest LPS level, TNF-α concentration was 23% lower in the high-dose WBB-V treatment compared to the control group (WBB-V: 0.45 ± 0.06 vs. RPMI: 0.55 ± 0.12, p = 0.003). IL-1β, and IL-10 were not modified by WBB fraction treatments. Conclusions These preliminary results indicate that both WBB-P and WBB-V fractions mitigate inflammatory responses in LPS treated WB of children. Blueberry fractions do not impact IL-1β or IL-10 secretion by immune cells in WB. Funding Sources Center for Childhood Obesity Prevention NIH-NIGMS 5P20GM109096. USDA-ARS 6026–51,000-012–06S. The Arkansas Center for Advancing Pediatric Therapeutics NIH 8UG1OD024945.