Vascular changes in human skin after ultraviolet irradiation

Abstract

Blood-flow changes in human skin after ultraviolet irradiation at 250 and 300 nm have been measured by three separate methods. Those methods which measure overall blood-flow changes in the skin showed increased flow after irradiation at both wavelengths. A method which measured flow only in the superficial vessels showed a slight increase in flow after low doses of both wavelengths, but in contrast, after higher doses, this method showed a marked reduction in flow through the upper dermal vessels. This reduction in flow is probably due to stasis in these superficial vessels, perhaps secondary to vascular damage. Contrary to previous reports, blood-flow changes after irradiation at 250 and 300 nm are similar and may be mediated by identical mechanisms.

The effects of indomethacin on arachidonic acid and prostaglandins e2 and f2alpha levels in human skin 24 h after u.v.B and u.v.C irradiation.

“…Blood flow in non-irradiated and in irradiated skin, before and after oral indomethacin, was dmined by a photoelectric plethysmographic technique (Ramsay & Challoner, 1976).…”

Ultraviolet Radiation in Wound Care: Sterilization and Stimulation

“…30 Increased blood flow changes in human skin following UV irradiation at both 250 and 300 nm have been measured. 31 However, in case of superficial vessels, following low doses of both wavelengths a slight increase in blood flow, and following higher doses, a marked reduction in blood flow was observed. This reduction was attributed to the stasis in these superficial vessels, perhaps, secondary to vascular damage.…”

“…This reduction was attributed to the stasis in these superficial vessels, perhaps, secondary to vascular damage. 31 The keratinocytederived vascular endothelial growth factor (VEGF, also known as VPF or vascular permeability factor) provides the major cutaneous angiogenic activity in epidermal keratinocytes and its overexpression results in hyperpermeable dermal capillaries. 32 34 In a previous study, hypoxia through generation of ROS was shown to increase the survival of human ASCs, and the conditioned medium derived from hypoxiapreconditioned ASCs supported endothelial cell survival and endothelial tube formation.…”

“…63 UV is absorbed directly by extracellular fluid components and capillaries. 27 This absorption promotes endothelial cell proliferation, 26 and induced the expression of VEGF 64 followed by temporary epidermal hyperplasia and increase in epidermal thickness, enhanced reepithelialization or de-squamation of the leading edge of peri-ulcer epidermal cells, granulation tissue, 65 release of PGE, which play a role in UVinduced erythema and may mediate cell proliferation, 26 histamine release, which contributes to the increased skin blood flow, 31 increased vascular permeability, which leads to cellular elements of repair in the dermis early as 30 min following UV exposure and a delayed erythema a few hours later, 66 initial decrease and after a few days an accelerated rate of DNA, RNA, and protein synthesis, which contributes to skin thickening as a late-phase response, 26 and bacterial cell inactivation.…”

Optimum Deflection Angle of Double Angular Focusing Two-Magnet System for Use in Nuclear Time Spectroscopy

“…Several investigators have measured temperature of uv-irradiated skin from this viewpoint (Van der Leun 1966, Ramsay and Cripps 1970, Ramsay and Challoner 1976, Challoner and Woodrough 1978. As measurements were done several hours after exposure the temperature changes detected were really due to the ultraviolet erythema and not a consequence of the heat absorbed during the irradiation.…”