TY - JOUR
T1 - Acute ascorbate supplementation alone or combined with arginase inhibition augments reflex cutaneous vasodilation in aged human skin
AU - Holowatz, Lacy A.
AU - Thompson, Caitlin S.
AU - Kenney, W. Larry
PY - 2006
Y1 - 2006
N2 - Full expression of reflex cutaneous vasodilation (VD) is dependent on nitric oxide (NO) and is attenuated in older humans. NO may be decreased by an age-related increase in reactive oxygen species or a decrease in L-arginine availability via upregulated arginase. The purpose of this study was to determine the effect of acute antioxidant supplementation alone and combined with arginase inhibition on reflex VD in aged skin. Eleven young (Y; 22 ± 1 yr) and 10 older (O; 68 ± 1 yr) human subjects were instrumented with four intradermal microdialysis (MD) fibers. MD sites were control (Co), NO synthase inhibited (NOS-I), L-ascorbate supplemented (Asc), and Asc + arginase-inhibited (Asc + A-I). After baseline measurements, subjects underwent whole body heating to increase oral temperature (Tor) by 0.8°C. Red blood cell flux was measured by using laser-Doppler flowmetry, and cutaneous vascular conductance (CVC) was calculated (CVC = flux/mean arterial pressure) and normalized to maximal (CVCmax). VD during heating was attenuated in O (Y: 37 ± 3 vs. O: 28 ± 3% CVCmax; P < 0.05). NOS-I decreased VD in both groups compared with Co (Y: 20 ± 4; O: 15 ± 2% CVCmax; P > 0.05 vs. Co within group). Asc and Asc + A-I increased VD beyond Co in O (Asc: 35 ± 4% CVCmax; Asc + A-I: 41 ± 3% CVCmax; P < 0.001) but not in Y (Asc: 36 ± 3% CVCmax; Asc + A-I: 40 ± 5% CVCmax; P > 0.05). Combined Asc + A-I resulted in a greater increase in VD than Asc alone in O (P = 0.001). Acute Asc supplementation increased reflex VD in aged skin. Asc combined with arginase inhibition resulted in a further increase in VD above Asc alone, effectively restoring CVC to the level of young subjects.
AB - Full expression of reflex cutaneous vasodilation (VD) is dependent on nitric oxide (NO) and is attenuated in older humans. NO may be decreased by an age-related increase in reactive oxygen species or a decrease in L-arginine availability via upregulated arginase. The purpose of this study was to determine the effect of acute antioxidant supplementation alone and combined with arginase inhibition on reflex VD in aged skin. Eleven young (Y; 22 ± 1 yr) and 10 older (O; 68 ± 1 yr) human subjects were instrumented with four intradermal microdialysis (MD) fibers. MD sites were control (Co), NO synthase inhibited (NOS-I), L-ascorbate supplemented (Asc), and Asc + arginase-inhibited (Asc + A-I). After baseline measurements, subjects underwent whole body heating to increase oral temperature (Tor) by 0.8°C. Red blood cell flux was measured by using laser-Doppler flowmetry, and cutaneous vascular conductance (CVC) was calculated (CVC = flux/mean arterial pressure) and normalized to maximal (CVCmax). VD during heating was attenuated in O (Y: 37 ± 3 vs. O: 28 ± 3% CVCmax; P < 0.05). NOS-I decreased VD in both groups compared with Co (Y: 20 ± 4; O: 15 ± 2% CVCmax; P > 0.05 vs. Co within group). Asc and Asc + A-I increased VD beyond Co in O (Asc: 35 ± 4% CVCmax; Asc + A-I: 41 ± 3% CVCmax; P < 0.001) but not in Y (Asc: 36 ± 3% CVCmax; Asc + A-I: 40 ± 5% CVCmax; P > 0.05). Combined Asc + A-I resulted in a greater increase in VD than Asc alone in O (P = 0.001). Acute Asc supplementation increased reflex VD in aged skin. Asc combined with arginase inhibition resulted in a further increase in VD above Asc alone, effectively restoring CVC to the level of young subjects.
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U2 - 10.1152/ajpheart.00648.2006
DO - 10.1152/ajpheart.00648.2006
M3 - Article
C2 - 16905599
AN - SCOPUS:33845502720
SN - 0363-6135
VL - 291
SP - H2965-H2970
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
IS - 6
ER -