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Exposure to non-extreme solar UV daylight: spectral characterization, effects on skin and photoprotection.

Marionnet C, Tricaud C, Bernerd F - Int J Mol Sci (2014)

Bottom Line: The link between chronic sun exposure of human skin and harmful clinical consequences such as photo-aging and skin cancers is now indisputable.These effects are mostly due to ultraviolet (UV) rays (UVA, 320-400 nm and UVB, 280-320 nm).However, a limited part of the global population is exposed daily to such intense irradiance and until recently little attention has been paid to solar exposure that does not induce any short term clinical impact.

View Article: PubMed Central - PubMed

Affiliation: Oréal Research and Innovation, 1 avenue Eugène Schueller, 93601 Aulnay-sous-Bois, France. cmarionnet@rd.loreal.com.

ABSTRACT
The link between chronic sun exposure of human skin and harmful clinical consequences such as photo-aging and skin cancers is now indisputable. These effects are mostly due to ultraviolet (UV) rays (UVA, 320-400 nm and UVB, 280-320 nm). The UVA/UVB ratio can vary with latitude, season, hour, meteorology and ozone layer, leading to different exposure conditions. Zenithal sun exposure (for example on a beach around noon under a clear sky) can rapidly induce visible and well-characterized clinical consequences such as sunburn, predominantly induced by UVB. However, a limited part of the global population is exposed daily to such intense irradiance and until recently little attention has been paid to solar exposure that does not induce any short term clinical impact. This paper will review different studies on non-extreme daily UV exposures with: (1) the characterization and the definition of the standard UV daylight and its simulation in the laboratory; (2) description of the biological and clinical effects of such UV exposure in an in vitro reconstructed human skin model and in human skin in vivo, emphasizing the contribution of UVA rays and (3) analysis of photoprotection approaches dedicated to prevent the harmful impact of such UV exposure.

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Related in: MedlinePlus

Morphological changes induced by the biologically efficient doses of DUVR (13 J/cm2), of UVA (25 J/cm2) or of UV-SSR (5.4 J/cm2) in reconstructed human skin [43,44,45,46]. Black arrows indicate the zone where the incidence of fibroblasts has decreased. White arrows indicate sunburn cells.
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ijms-16-00068-f003: Morphological changes induced by the biologically efficient doses of DUVR (13 J/cm2), of UVA (25 J/cm2) or of UV-SSR (5.4 J/cm2) in reconstructed human skin [43,44,45,46]. Black arrows indicate the zone where the incidence of fibroblasts has decreased. White arrows indicate sunburn cells.

Mentions: Since the MED determination could not be achieved in such in vitro experimental conditions, the biological efficient dose (BED) has been previously defined as the minimal dose able to induce morphological alterations after acute UV exposure [42,43]. Histological analysis of this reconstructed skin model exposed to increasing doses of DUVR established the DUVR BED at 13 J/cm2. At this dose, observed alterations were mostly located in the dermal compartment and were characterized by the disappearance of fibroblasts. Such changes have also been observed following exposure to UVA alone [42,43] (Figure 3). Some alterations were also detected in the epidermis. These included slight alterations in the granular layer resembling those observed after UVA exposure, as well as thinning of the epidermis and thickening of the cornified layer. Moreover, at this BED of DUVR, few sunburn cells and p53 positive keratinocytes could be detected. The histological damage induced by DUVR was correlated with the release of the well-known matrix metalloproteinase 1 (MMP-1), a photo-aging marker in the culture medium of reconstructed skin [44,45]. To summarize, the BED of 13 J/cm2 DUVR induced histological alterations mostly in the dermis, as observed after UVA and some alterations in the epidermis that were similar to those induced by UV-SSR or UVB (Figure 3) [46]. The lower dose of 7 J/cm2 DUVR was not sufficiently high to induce any of the cited histological damage. Repetitive exposures to DUVR for five consecutive days showed drastic alterations in the dermis and in the epidermis, even with the sub-BED dose of 7 J/cm2, attesting that chronic exposure to low DUVR dose may account for long term harmful consequences [45].


Exposure to non-extreme solar UV daylight: spectral characterization, effects on skin and photoprotection.

Marionnet C, Tricaud C, Bernerd F - Int J Mol Sci (2014)

Morphological changes induced by the biologically efficient doses of DUVR (13 J/cm2), of UVA (25 J/cm2) or of UV-SSR (5.4 J/cm2) in reconstructed human skin [43,44,45,46]. Black arrows indicate the zone where the incidence of fibroblasts has decreased. White arrows indicate sunburn cells.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4307236&req=5

ijms-16-00068-f003: Morphological changes induced by the biologically efficient doses of DUVR (13 J/cm2), of UVA (25 J/cm2) or of UV-SSR (5.4 J/cm2) in reconstructed human skin [43,44,45,46]. Black arrows indicate the zone where the incidence of fibroblasts has decreased. White arrows indicate sunburn cells.
Mentions: Since the MED determination could not be achieved in such in vitro experimental conditions, the biological efficient dose (BED) has been previously defined as the minimal dose able to induce morphological alterations after acute UV exposure [42,43]. Histological analysis of this reconstructed skin model exposed to increasing doses of DUVR established the DUVR BED at 13 J/cm2. At this dose, observed alterations were mostly located in the dermal compartment and were characterized by the disappearance of fibroblasts. Such changes have also been observed following exposure to UVA alone [42,43] (Figure 3). Some alterations were also detected in the epidermis. These included slight alterations in the granular layer resembling those observed after UVA exposure, as well as thinning of the epidermis and thickening of the cornified layer. Moreover, at this BED of DUVR, few sunburn cells and p53 positive keratinocytes could be detected. The histological damage induced by DUVR was correlated with the release of the well-known matrix metalloproteinase 1 (MMP-1), a photo-aging marker in the culture medium of reconstructed skin [44,45]. To summarize, the BED of 13 J/cm2 DUVR induced histological alterations mostly in the dermis, as observed after UVA and some alterations in the epidermis that were similar to those induced by UV-SSR or UVB (Figure 3) [46]. The lower dose of 7 J/cm2 DUVR was not sufficiently high to induce any of the cited histological damage. Repetitive exposures to DUVR for five consecutive days showed drastic alterations in the dermis and in the epidermis, even with the sub-BED dose of 7 J/cm2, attesting that chronic exposure to low DUVR dose may account for long term harmful consequences [45].

Bottom Line: The link between chronic sun exposure of human skin and harmful clinical consequences such as photo-aging and skin cancers is now indisputable.These effects are mostly due to ultraviolet (UV) rays (UVA, 320-400 nm and UVB, 280-320 nm).However, a limited part of the global population is exposed daily to such intense irradiance and until recently little attention has been paid to solar exposure that does not induce any short term clinical impact.

View Article: PubMed Central - PubMed

Affiliation: Oréal Research and Innovation, 1 avenue Eugène Schueller, 93601 Aulnay-sous-Bois, France. cmarionnet@rd.loreal.com.

ABSTRACT
The link between chronic sun exposure of human skin and harmful clinical consequences such as photo-aging and skin cancers is now indisputable. These effects are mostly due to ultraviolet (UV) rays (UVA, 320-400 nm and UVB, 280-320 nm). The UVA/UVB ratio can vary with latitude, season, hour, meteorology and ozone layer, leading to different exposure conditions. Zenithal sun exposure (for example on a beach around noon under a clear sky) can rapidly induce visible and well-characterized clinical consequences such as sunburn, predominantly induced by UVB. However, a limited part of the global population is exposed daily to such intense irradiance and until recently little attention has been paid to solar exposure that does not induce any short term clinical impact. This paper will review different studies on non-extreme daily UV exposures with: (1) the characterization and the definition of the standard UV daylight and its simulation in the laboratory; (2) description of the biological and clinical effects of such UV exposure in an in vitro reconstructed human skin model and in human skin in vivo, emphasizing the contribution of UVA rays and (3) analysis of photoprotection approaches dedicated to prevent the harmful impact of such UV exposure.

Show MeSH
Related in: MedlinePlus