Atherosclerotic cardiovascular complications are the leading cause of death in diabetic patients. Monocyte adhesion is an early event for atherogenesis. Previous studies demonstrated that dark-skin berries had cardiovascular protective effects. We hypothesize that Saskatoon berry (SB) powder may reduce monocyte adhesion in leptin receptor-deficient (db/db) diabetic mice.
Wild-type and db/db mice were fed with chow or supplemented with SB powder. Anthocyanins in SB powder were identified using mass spectrometry. Mouse monocytes were incubated with mouse aorta. Monocyte adhesion was counted under microscopy. Inflammatory or metabolic markers in blood or tissue were analyzed using immunological or biochemical methods.
SB powder significantly reduced monocyte adhesion to aorta from diabetic db/db mice compared to regular chow. The increased monocyte adhesion to aorta was normalized in db/db mice treated with ≥5% of SB powder for 4 weeks. Increased contents of Nicotinamide adenine dinucleotide phosphate oxidase (NADPH) oxidase-4, heat shock factor-1, monocyte chemotactic protein (MCP)-1, intracellular adhesion molecule (ICAM)-1, P-selectin, tumor necrosis factor-α, plasminogen activator inhibitor (PAI)-1 and urokinase plasminogen activator in aorta or heart apex, elevated plasma PAI-1 and MCP-1 were detected in db/db mice on chow compared to wild-type mice on the same diet; 5% SB powder inhibited the increases of inflammatory, fibrinolytic or stress regulators in aorta or heart apex of db/db mice. Monocyte adhesion positively correlated with blood glucose, cholesterol, body weight, heart MCP-1, PAI-1 or ICAM-1.
The findings suggest that SB powder attenuated monocyte adhesion to aorta of db/db mice, which was potentially mediated through inhibiting the inflammatory, stress and/or fibrinolyic regulators.
Corresponding author. Diabetes Research Group, University of Manitoba, 835-715 McDermot Ave, Winnipeg, MB R3E 3P4, Canada. Tel.: +1 204 789 3816; fax: +1 204 789 3987.