Light-sheet microscopy reveals site-specific 3-dimensional patterns of the cutaneous vasculature and pronounced rarefication in aged skin

The skin has a 3-dimensional structure that includes several appendages, such as sweat glands and sebaceous glands, as well as lymphatic and blood vessels and nerves. In spite of its complex three-dimensional structure, histological studies of the skin, including quantitative analyses of specific cell types and structures, predominantly use two-dimensional sections. Thus, for example the tortuosity of a blood vessel is not captured in histological sections [1]. Recently, tissue clearing methods have been developed, rendering tissues translucent, as tools to visualize the 3-dimensional structure of vessels and nerves in various tissues, including brain, kidney and skin, and even in an entire mouse [2].