Apocynin and tempol restores cutaneous microvascular function in healthy, salt‐resistant adults on a high sodium diet (LB686)

Abstract

The purpose of this study was to determine if NADPH derived superoxide plays a role in attenuating cutaneous vasodilation in response to local heating in healthy, salt‐resistant adults on a high sodium diet. Nineteen healthy adults (33±3yrs) participated in a controlled feeding study. Subjects completed 7 days of a low sodium (LS) diet (20mmol sodium/day) and 7 days of a high sodium (HS) diet (300mmol sodium/day) in random order. On the final day of LS and HS diets cutaneous microvascular function was assessed using a standard heating protocol. RBC flux was measured via laser Doppler flowmetry coupled with interdermal microdialysis for the local delivery of 10µM tempol (scavenging superoxide) and 100 µM apocynin (inhibiting NADPH oxidase). Once a stable post‐heating plateau was achieved, 10mM L‐NAME was infused through all sites to determine NO contribution to vasodilation. The plateau phase of cutaneous vasodilation was attenuated in the HS condition compared to LS (91.0±1.8 vs 83.4±1.9; p<0.05) and was restored with the local infusion of both tempol and apocynin (p<0.05). The NO contribution to cutaneous vasodilation was also decreased on the HS diet compared to LS (62.7±4.2 vs 52.3±4.6; p<0.05). This was restored with the infusion of apocynin (p< 0.05) but was not improved by tempol (p=0.173). These finding suggest that NADPH derived superoxide plays a role in dietary sodium induced decreases in cutaneous vasodilation in response to local heating.Grant Funding Source: Supported by NIH Grant R01 HL104106‐01A1