Shiseido Global Innovation Center, Yokohama, Japan.
Takamatsu Information Technology, Takamatsu, Japan.
Photodermatol Photoimmunol Photomed. 2020 May;36(3):226-232. doi: 10.1111/phpp.12542. Epub 2020 Mar 11.
Ultraviolet (UV) irradiation to skin induces biological responses to protect and heal the wounded tissue. Cutaneous blood vessels play an important role in maintaining skin homeostasis, by inducing angiogenesis and vasodilation. However, the vascular dynamics in vivo, such as morphological changes over time and their depth dependency, are not fully understood.
Ten Asian males were enrolled in this study and received UV (UVA + UVB) irradiation at two minimal erythema dose (MED) to the inner upper arm. Changes in epidermal thickness and vascular structures associated with UV irradiation were evaluated over time for 28 days by optical coherence tomography angiography (OCTA). This technique enables non-invasive visualization of three-dimensional vascular networks in human skin based on OCT assessment of skin structures with near-infrared light.
Notable dilation of vascular structures and increases in epidermal thickness were observed after UV irradiation. Vessel density was markedly increased from the papillary dermis to the upper reticular dermis at a depth of 200 µm. These increases in vascular density showed significant persistence even at 28 days after UV irradiation.
We visualized the vascular structural changes caused by UV irradiation and revealed that the effects of a single UV irradiation at 2 MED persisted for up to 28 days after exposure. The OCTA technique allows not only the in situ assessment of micro-vasculature in human skin but also its monitoring of vascular dynamics over time.
紫外线（UV）辐射到皮肤会引起生物反应，以保护和治愈受伤的组织。皮肤血管在维持皮肤稳态方面起着重要作用，通过诱导血管生成和血管扩张。然而，体内的血管动力学，如随时间的形态变化及其深度依赖性，尚未完全了解。
本研究纳入了 10 名亚洲男性，他们在内臂接受了两个最小红斑剂量（MED）的 UV（UVA+UVB）照射。通过光学相干断层扫描血管造影术（OCTA）在 28 天内评估表皮厚度和与 UV 照射相关的血管结构的随时间变化。该技术基于近红外光对皮肤结构的 OCT 评估，可实现人类皮肤中三维血管网络的非侵入性可视化。
UV 照射后观察到血管结构明显扩张和表皮厚度增加。血管密度从乳头真皮到 200µm 深度的网状真皮明显增加。即使在 UV 照射后 28 天，这些血管密度的增加仍具有显著的持久性。
我们可视化了 UV 照射引起的血管结构变化，并揭示了单次 2 MED 的 UV 照射的效果在暴露后长达 28 天内持续存在。OCTA 技术不仅允许原位评估人类皮肤中的微血管，还可以监测随时间的血管动力学。
