US EPA

982331 

Journal Article 

Abstract 

Whole body UVA-irradiation lowers systemic blood pressure by release of nitric oxide from intracutaneous nitrite 

Suschek, CV; Oplander, C; Van Faassen, EE; Heiss, C; Kelm, M; Halmer, D; Murtz, M; Pallua, N 

2009 

1 

Nitric Oxide
ISSN: 1089-8603
EISSN: 1089-8611 

20 

Supplement 

S44 

English 

WOS:000266761400091 

https://www.sciencedirect.com/science/article/pii/S1089860309000597
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Background: Human skin contains photolabile nitric oxide (NO) derivates like nitrite and nitroso componds (R-NO) at comparable high concentrations. When irradiated with UVA-light, nitrite and R-NO may undergo photodecomposition resulting in the formation of vasoactive NO. As UVA is known to penetrate the skin deep enough to reach the microvessels, we here tested the effect of whole body UVA irradiation on the blood pressure of healthy volunteers.
Methods: Whole body UVA irradiation of human volunteers was carried out in a commercial solarium with a suberythmal dose of 20 J/cm2 skin, and the effect of irradiation on mean arterial blood pressure measured. The concentrations of nitrite and R-NO in blood were quantified by reduction and subsequent detection of the release of gaseous NO with a chemiluminescence assay. Isotopically labelled 15NO was detected by Cavity Leak Out Spectroscopy (CALOS). Results: Exposure to whole-body UVA caused a rapid and significant drop in mean arterial blood pressure by 10.9 ± 1.8 % at 30 min after light exposure. In parallel blood samples showed a significant increase in plasma concentrations of RNO (74 ± 19 %) and nitrite (43 ± 22%) but decreases in blood pressure only significantly correlated with plasma R-NO (R2 = 0.74) but not nitrite (R2 = 0.01) concentration. All effects returned to normal values on the timescale of an hour. After application to the skin of cream containing isotopically labelled 15N-nitrite,
UVA irradiation led to significant levels of 15N labelled S-nitrosothiols in the blood plasma. Upon UVA, emanation of gaseous NO from the skin into the air could be detected with CLD. This photoyield of NO could be greatly enhanced by application of skin cream containing nitrite. Conclusion: UVA-irradiation of skin induces the cutaneous release of NO via photodecomposition of nitrite. Although some NO escapes into ambient air, a significant fraction is incorporated into nitrosospecies in the blood circulation and reduces the systemic blood pressure. The effect on blood pressure is significant even at suberythmal UVA doses as encountered in commercial tanning facilities. 

3rd International Role of Nitrite in Physiology, Pathophysiology and Therapeutics Meeting 

June 17-18, 2009