Long-Lasting Pigmentation (LLP) of Human Skin, a New Look at an Overlooked Response to UV
| Autor: | Sharon A. Miller, Sergio G. Coelho, Yanchun Zhou, Harry F. Bushar, Barbara Z. Zmudzka, Vincent J. Hearing, Janusz Z. Beer |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2009 |
| Předmět: |
Long lasting
Male medicine.medical_specialty Time Factors Erythema Ultraviolet Rays Population Human skin Skin Pigmentation Dermatology General Biochemistry Genetics and Molecular Biology Article medicine Eye color Humans education Ultraviolet radiation Melanins education.field_of_study business.industry Significant difference Dose-Response Relationship Radiation Phototype Phenotype Oncology Female medicine.symptom business |
| Popis: | Dear Sir, Induction of melanogenesis by ultraviolet radiation (UV) is a relatively slow process (Tadokoro et al., 2003; Tadokoro et al., 2005; Yamaguchi et al., 2008). UV-induces immediate pigment darkening (within minutes, remaining for hours) (Honigsmann et al., 1986; Routaboul et al., 1999), persistent pigment darkening (within hours, remaining for days) (Moyal et al., 2000; Moyal et al., 2006), and delayed pigmentation (within in days, remaining for weeks) (Ortonne, 1990; Tadokoro et al., 2003; Tadokoro et al., 2005; Young, 2006). The majority of humans lose UV-induced pigmentation (tan) within a relatively short time, however a significant segment of the population maintains such pigmentation for many months. However, no systematic studies of long-lasting pigmentation (LLP) have been reported. Anecdotally, people know that pigmentation persists after UV exposure as “tan lines”, but the mechanism of this extended pigmentary response has not been elucidated. A literature search revealed only one study reporting pigmentation remaining 6 months after exposure to two minimal erythema doses (MED)(Suh et al., 2007). We analyzed the persistence of UV-induced pigmentation in humans of different complexion (Figure 1) and analyzed factors that may predispose to LLP. We explored parameters that included gender, age, eye color, hair color, MED, minimal melanogenic dose (MMD), phototype, race/ethnicity, and constitutive pigmentation. Figure 2 shows that virtually all subjects exposed to ≥2 MED developed early pigmentation with a grade of ≥1 on a scale 0–4 (Table S1). A proportion of these subjects showed a pigmentation grade ≥1 at ≥9 months post-exposure. LLP+ subjects typically develop a strong pigmentation within days after UV exposure. This pigmentation remains robust on post-exposure day 16 (Figure 1). Induction of LLP depends on the UV exposure level: only a few our subjects developed LLP after 1 MED, but at 2 MED the proportion of LLP+ subjects was substantial, and it increased with increasing UV dose. Figure 1 LLP ≥9 months after ultraviolet (UV) exposure in six phototypes (1 - Burns easily, never tans; 2 - Burns easily, tans slightly; 3 - Burns slightly, tans light brown; 4 -Burns slightly, tans moderate brown; 5 - Burns rarely, tans dark brown; 6 ... Figure 2 Pigmentation after 1–4 MED of UV. Correlations between LLP+ occurrence and the three MED ranges, as defined in Appendix S1, were pronounced (Table 1 and Figure 3A). No subjects with MED 2 MED showed LLP frequency of 40–70%. The “Unequally Spaced Repeated Measures Linear Model” (Appendix S1) demonstrated a statistically significant difference from zero, with p |
| Databáze: | OpenAIRE |
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