Raspberry phenolics in serum from supplemented adults reduce inflammatory stress signals in HAPI rat microglial cells, in vitro

Authors: Fisher, Derek; Piccolo, Francesca; XIAO, MELODY - Illinois Institute Of Technology; BURTON-FREEMAN, B.M. - Illinois Institute Of Technology; Shukitt Hale, Barbara

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/9/2022
Publication Date: 11/16/2022
Citation: Fisher, D.R., Piccolo, F.X., Xiao, M., Burton-Freeman, B., Shukitt Hale, B. 2022. Raspberry phenolics in serum from supplemented adults reduce inflammatory stress signals in HAPI rat microglial cells, in vitro [abstract]. Society for Neuroscience Abstracts 2022. Program No. 621.10.

Interpretive Summary:

Technical Abstract: Age-related neurodegeneration and behavioral declines have been associated with increases in neuroinflammation and oxidative stress in the brain. Raspberries contain an array of bioactive phenolic compounds that may play a protective role against chronic age-related diseases, as these compounds exhibit potent antioxidant and anti-inflammatory activities. Because the bioactive compounds in foods are different than those found in circulating blood following consumption, we were interested in whether pre-treatment of stressed cells with serum from people fed raspberries might be a valid model system for assessing their anti-inflammatory effects. The effects of acute raspberry supplementation in 27 older (55-70 years old), overweight/obese (BMI 27-35) adults were examined in a double-blind, placebo-controlled, crossover study. Participants consumed a raspberry or placebo drink with a high-fat breakfast challenge. Blood was collected at baseline (0 hour), then again at 2 and 6 hours post-consumption. HAPI rat microglial cells were treated with the serum (for each individual, at each timepoint, in duplicate) prior to stressor application with LPS at 200 ng/mL overnight, and expression of nitric oxide, TNFa, COX-2, and iNOS were measured by western blot and ELISA as inflammatory indices. Results showed that microglia treated with serum from participants who consumed raspberry demonstrated reduced LPS-induced neuroinflammation compared to cells treated with placebo in a time-dependent manner (p<0.05). For example, with raspberry supplementation, nitrite production was reduced in serum-treated microglia at both 2 and 6 hrs compared to control. Nitrite levels showed the greatest reduction at 2hr post-consumption, but at 6hr started to return to baseline, suggesting that ongoing supplementation may be needed. Therefore, berry metabolites, present in the circulating blood, may be mediating the anti-inflammatory effects of dietary berry fruit, but further chronic studies are needed to determine on benefits to health.