Inorganic nitrate supplementation attenuates conduit artery retrograde and oscillatory shear in older adults.

Inorganic nitrate supplementation attenuates conduit artery retrograde and oscillatory shear in older adults.
Am J Physiol Heart Circ Physiol. 2021 Jan 15;:
Authors: Casey DP, Bock JM
Abstract
Aging causes deleterious changes in resting conduit artery shear patterns and reduced blood flow during exercise partially attributable to reduced nitric oxide (NO). Inorganic nitrate increases circulating NO bioavailability and may therefore improve age-associated changes in shear rate as well as exercise hyperemia. 10 older adults (67±3yrs) consumed 4.03mmol nitrate and 0.29mmol nitrite (active) or devoid of both (placebo) daily for 4wks in randomized, double-blinded, crossover fashion. Brachial artery diameter (D) and blood velocity (Vmean) were measured via Doppler ultrasound at rest for the characterization of shear profile as well as during two handgrip exercise trials (4 and 8kg) for calculation of forearm blood flow (Vmean*cross-sectional area, FBF) and conductance (FBF/mean arterial pressure, FVC). Plasma [nitrate] and [nitrite] increased following active (P<0.05 for both) but not placebo (P=0.68 and 0.40, respectively) supplementation. Neither mean nor antegrade shear rate changed following either supplement (beverage-by-time P=0.14 and 0.21, respectively). Retrograde (-13.4±7.0 to -9.7±6.8s-1) and oscillatory (0.20±0.08 to 0.15±0.09A.U., P<0.05 for both) shear decreased following active, but not placebo (P=0.81 and 0.70, r...

Source: American Journal of Physiology. Heart and Circulatory Physiology - January 15, 2021 Category: Physiology Authors: Casey DP, Bock JM Tags: Am J Physiol Heart Circ Physiol Source Type: research