Effects of repeated sunbed exposures on the human skin. In vivo measurements with confocal microscopy

Abstract

Sunbed exposures seem to induce photoadaptation not only by skin pigmentation but also by epidermal thickening that is predominantly due to an increase in thickness of the horny layer. Moreover, our data indicate that UVA radiation has an influence on the cell size of the granular layer. CLSM is a promising tool for photobiological studies in vivo.

Topically applied vitamin C increases the density of dermal papillae in aged human skin

“…Kligman shows an inverse relationship between turnover and the size of corneocytes [9]. A similar relationship could be shown for the size of cells in the granular layer [25]. Parallel to this, the smaller size of granular layer cells in the vitamin C treated areas can be interpreted as a sign for higher proliferative activity of the epidermis.…”

Is superficial burn caused by ultraviolet radiation (sunburn) comparable to superficial burn caused by heat - a histomorphological comparison byin vivoReflectance-Mode-Confocal Microscopy

“…In an experimental model, Gambichler et al by means of a predecessor confocal model described epidermal thickening and increased pigmentation as chronic effects of repeated sunbed exposures. 11 Although our study did not aim to evaluate chronic effects, we obtained comparable data for acute ultraviolet overexposure effects for epidermal thickening 24 h after both sunburn and superficial thermal injury. Thus, our data suggest that both sunburn and thermal injuries lead to a comparable acute thickening of the epidermis.…”

“…6,[9][10][11] Whereas these studies yielded limited data concerning the effects of local heat-induced morphological alterations, the effects of ultraviolet radiation on the human skin has been subject to intensive investigation in recent years. 6,9,10,12 In this respect, both the effects of wavelength-separated and cumulative ultraviolet Figure 1 The histometric evaluation of the stratum corneum thickness as the distance between skin surface and the apical plane of the granular layer demonstrates at 24 h post-injury significant (*P < 0.05) decrease in thermally injured sites (TI group), whereas it increased in sunburned skin (SB group), compared to the health control.…”

“…By contrast, the chronic effects of ultraviolet radiation on granular cells have been reported as reduced volumetric growth of the solitary cells due to radiation-induced increase of the epidermal turnover following repeated exposure to ultraviolet light. 11 . The squamous skin peeling, however, present in all patients in the SB group at followup after 2 weeks indicates that accelerated epidermal turnover may be caused by acute ultraviolet overexposure as well.…”

In vivo reflectance-mode confocal microscopy provides insights in human skin microcirculation and histomorphology

“…Thus, a high resolution imaging technique to visualize the human skin microcirculation and the associated cellular morphology would be novel in microcirculation research. Reflectance-mode confocal microscopy (RCM) enables real-time and in vivo high resolution imaging of the human skin and has been used in numerous studies in dermatology and the burn care arena [6][7][8][9][10]. For correlation, confocal images were compared to histological sectioning and a high sensitivity of 82.9% and specificity of 95.7% was found [9,10].…”