Dietary Blueberry Ameliorates Vascular Complications in Diabetic Mice Possibly through NOX4 and Modulates Composition and Functional Diversity of Gut Microbes.

SCOPE: In diabetes, endothelial inflammation and dysfunction play a pivotal role in the development of vascular disease. This study investigates the effect of dietary blueberries on vascular complications and gut microbiome in diabetic mice. METHODS AND RESULTS: Seven-week-old diabetic db/db mice consume a standard diet (db/db) or a diet supplemented with 3.8% freeze-dried blueberry (db/db+BB) for 10 weeks. Control db/+ mice are fed a standard diet (db/+). Vascular inflammation is assessed by measuring monocyte binding to vasculature and inflammatory markers. Isometric tension procedures are used to assess mesenteric artery function. db/db mice exhibit enhanced vascular inflammation and reduced endothelial-dependent vasorelaxation as compared to db/+ mice, but these are improved in db/db+BB mice. Blueberry supplementation reduces the expression of NOX4 and IκKß in the aortic vessel and vascular endothelial cells (ECs) isolated from db/db+BB compared to db/db mice. The blueberry metabolites serum reduces glucose and palmitate induced endothelial inflammation in mouse aortic ECs. Further, blueberry supplementation increases commensal microbes and modulates the functional potential of gut microbes in diabetic mice. CONCLUSION: Dietary blueberry suppresses vascular inflammation, attenuates arterial endothelial dysfunction, and supports the growth of commensal microbes in diabetic mice. The endothelial-specific vascular benefits of blueberries are mediated through NOX4 signaling.

Circulating metabolites of strawberry mediate reductions in vascular inflammation and endothelial dysfunction in db/db mice.

BACKGROUND: Cardiovascular disease is 2-4-fold more prevalent in patients with diabetes. Human studies support the cardiovascular benefits of strawberry consumption but the effects of strawberry on diabetic vasculature are unknown. We tested the hypothesis that dietary strawberry supplementation attenuates vascular inflammation and dysfunction in diabetic mice. METHODS: Seven-week-old diabetic db/db mice that consumed standard diet (db/db) or diet supplemented with 2.35% freeze-dried strawberry (db/db + SB) for ten weeks were compared to non-diabetic control mice (db/+). Indices of vascular inflammation and dysfunction were measured. Endothelial cells (ECs) were isolated from the vasculature to determine the influence of strawberry on them. The effect of metabolites of strawberry on endothelial inflammation was determined by incubating mouse aortic ECs (MAECs) with ±5% serum, obtained from strawberry fed mice (metabolites serum) or standard diet fed mice (control serum) ±â€¯25 mM glucose and 100 µM palmitate. RESULTS: db/db mice exhibited an increased monocyte binding to vessel, elevated blood pressure, and reduced endothelial-dependent vasorelaxation compared with db/+ mice but each defect was attenuated in db/db + SB mice. The elevation of inflammatory molecules, NOX2 and inhibitor-κB kinase observed in ECs from db/db vs. db/+ mice was suppressed in db/db + SB mice. Glucose and palmitate increased endothelial inflammation in MAECs but were normalized by co-incubation with metabolites serum. CONCLUSIONS: Dietary supplementation of strawberry attenuates indices of vascular inflammation and dysfunction in diabetic db/db mice. The effect of strawberry on vasculature is endothelial-dependent and possibly mediated through their circulating metabolites. Strawberry might complement conventional therapies to improve vascular complications in diabetics.