Montmorency cherry supplementation attenuates vascular dysfunction induced by prolonged forearm occlusion in overweight middle-aged men

Abstract

Flavonoid supplementation improves brachial artery flow-mediated dilatation (FMD), but it is not known whether flavonoids protect against vascular dysfunction induced by ischemia-reperfusion (IR) injury and associated respiratory burst. In a randomized, double-blind, placebo-controlled, crossover study, we investigated whether 4-weeks supplementation with freeze-dried Montmorency cherry (MC) attenuated suppression of FMD after IR induced by prolonged forearm occlusion. Twelve physically inactive middle-aged men (52.8+/-5.8y, BMI: 28.1+/-5.3kg.m-2) consumed MC (235mg.d-1 anthocyanins) or placebo capsules for 4-weeks, with supplementation blocks separated by 4-weeks washout. Pre and post each supplementation block, FMD responses and plasma nitrate and nitrite ([NO2-]) concentrations were measured at baseline and 15, 30, and 45min after prolonged (20-min) forearm occlusion. FMD response was significantly depressed by the prolonged occlusion (p<0.001). After 45min reperfusion, FMD was restored to baseline levels after MC (FMD pre: -30.5+/-8.4%, post: -0.6+/-9.5%) but not placebo supplementation (FMD pre: -11.6+/-10.6, post: -25.4+/-4.0%; condition x supplement interaction: p=0.038). Plasma [NO2-] decreased after prolonged occlusion but recovered faster after MC compared to placebo (45min to baseline; MC: pre: -15.3+/-9.6, post: -6.2+/-8.1; Placebo: pre: -16.3+/-5.9, post: -27.7+/-11.1 nmol.L-1; condition x supplement x time interaction: p=0.033). Plasma [Prx2] was significantly higher after MC (pre: 22.8+/-1.4, post: 28.0+/-2.4 ng.mL-1, p=0.029) but not after placebo supplementation (pre: 22.1+/-2.2, post: 23.7+/-1.5 ng.mL-1). In conclusion, 4-weeks MC supplementation enhanced recovery of endothelium-dependent vasodilatation after IR, in parallel with faster recovery of plasma [NO2-], suggesting NO dependency. These protective effects seem to be related to increased plasma [Prx2], presumably conferring protection against the respiratory burst during reperfusion.