Serum from aged humans supplemented with blueberry or strawberry reduces inflammatory stress signals in HAPI rat microglial cells, in vitro

Authors: Rutledge, Grant; Fisher, Derek; Miller, Marshall; Thangthaeng, Nopporn; Kelly, Megan; BIELINSKI, DONNA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; Shukitt-Hale, Barbara

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/15/2019
Publication Date: 5/7/2019
Citation: Rutledge, G.A., Fisher, D.R., Miller, M.G., Thangthaeng, N., Kelly, M.E., Bielinski, D.F., Shukitt Hale, B. 2019. Serum from aged humans supplemented with blueberry or strawberry reduces inflammatory stress signals in HAPI rat microglial cells, in vitro [abstract]. 2019 Berry Health Benefits Symposium Pre-Proceedings, p.87.

Interpretive Summary:

Technical Abstract: BACKGROUND: Age-related decrements in cognition are thought to result from the increased susceptibility to and accumulating effects of oxidative stress and inflammation. Berry fruits contain a variety of bioactive polyphenolic compounds that exhibit potent antioxidant and anti-inflammatory activities. We have shown that consumption of freeze-dried whole berry powder, equivalent to 1 cup/day of blueberry (BB) or 2 cups/day of strawberry (SB), can differentially improve some aspects of cognition in healthy, older adults, compared to placebo-supplemented controls. OBJECTIVE: Because the bioactive compounds in foods are different than those found in circulation following consumption, we were interested in whether pre-treatment of stressed cells with serum from people fed these foods may be a more valid model system than treating with extracts of the foods themselves for assessing their anti-inflammatory effects. METHODS: We investigated whether fasting and postprandial serum from BB- or SB-supplemented older adults (60-75yo), taken at baseline or after 45 or 90 days of supplementation, would reduce the production of inflammatory and oxidative stress signals, as measured by western blot and ELISA techniques, compared to a placebo group, in LPS-stressed HAPI rat microglial cells, in vitro. RESULTS: Serum from both blueberry and strawberry reduced nitrite production, iNOS and COX-2 expression and TNFa release relative to serum from placebo controls (p < 0.05). Protection was greatest with serum from the 90-day time-point, suggesting that ongoing supplementation may provide the most health benefits. Serum was protective in both fasted and postprandial conditions, suggesting that the meal did not challenge subjects’ ability to regulate oxidative and inflammatory stress. CONCLUSIONS: These results suggest that berry metabolites, present in the circulating blood, may be mediating the anti-inflammatory effects of dietary berry fruit.