L-Citrulline supplementation attenuates aortic pulse pressure and wave reflection responses to cold stress in older adults

Abstract

Augmented aortic systolic blood pressure (SBP) and wave reflection via sympathetic-mediated vasoconstriction elevates the risk for adverse cardiovascular events in older adults. L-citrulline (L-CIT) supplementation has shown to reduce aortic SBP and pulse pressure (PP) responses to cold pressor test (CPT) induced sympathoactivation in young men. The aim of this study was to elucidate the efficacy of L-CIT supplementation to attenuate aortic hemodynamic responses to CPT in older adults. Sixteen older adults were randomly assigned to placebo or L-CIT (6g/day) for 14-days in a crossover, double-blind, placebo-controlled design. Brachial SBP and aortic SBP, PP, augmented pressure (AP), augmentation index standardized at 75bpm (AIx@75), and pressure of the forward (Pf) and reflected (Pb) waves were evaluated at rest and during CPT pre- and post-intervention. Although no hemodynamic changes at rest, brachial SBP (Δ-12±18 vs. Δ4±14mmHg; P=0.008) and aortic SBP (Δ-10±14 vs. Δ4±12mmHg; P=0.005), PP (Δ-10±12 vs. Δ4±11mmHg; P=0.002), AP (Δ-4±4 vs. Δ2±7mmHg; P=0.004), AIx@75 (Δ-3.2±7.2 vs. Δ2.2±6.9%; P=0.038), Pf (Δ-6±10 vs. Δ3±9mmHg; P=0.019), and Pb (Δ-4±6 vs. Δ2±6mmHg; P=0.008) responses to the CPT were significantly attenuated following L-CIT supplementation vs. placebo. L-CIT supplementation attenuated aortic pulsatile pressure and pressure wave reflection responses to CPT in older adults, providing possible cardioprotection during cold-induced sympathoactivation in older adults.