Increased sensitivity to peroxidative agents as a possible pathogenic factor of melanocyte damage in vitiligo

Vittoria Maresca, Maria Roccella, Francesca Roccella, Emanuela Camera, Giuseppe Del Porto, Siro Passi, Paola Grammatico, Mauro Picardo

Research output: Contribution to journalArticle

Abstract

To examine the sensitivity of vitiligo melanocytes to external oxidative stress, we studied enzymatic and non-enzymatic anti-oxidants in cultured melanocytes of normal subjects (n = 20) and melanocytes from apparently normal skin of vitiligo patients (n = 10). The activity of superoxide dismutase and catalase and the intracellular concentrations of vitamin E and ubiquinone were evaluated in cultures at the fourth or fifth passage. In addition, cells were exposed to various concentrations of a peroxidizing agent, cumene hydroperoxide (CUH, 0.66-20 μM), for 1 and 24 h. Compared to normal melanocytes, vitiligo melanocytes showed normal superoxide dismutase and significantly lower catalase activities and higher vitamin E and lower ubiquinone levels. At the concentration used, CUH did not significantly affect cell number or viability of melanocytes after either period of culture. On the contrary, vitiligo melanocytes were susceptible to the toxic effect of CUH after 24 h of continuous treatment at concentrations greater than 6.6 μM. The degree of CUH toxicity correlated strictly with the anti- oxidant pattern, defined as the ratio between vitamin E concentration and catalase activity, suggesting that the alteration in the anti-oxidants was the basis for sensitivity to the external oxidative stress. Our results demonstrate the presence of an imbalance in the anti-oxidant system in vitiligo melanocytes and provide further support for a free radical-mediated damage as an initial pathogenic event in melanocyte degeneration in vitiligo.

Original languageEnglish
Pages (from-to)310-313
Number of pages4
JournalJournal of Investigative Dermatology
Volume109
Issue number3
Publication statusPublished - 1997

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Keywords

  • Catalase
  • Free radicals
  • Oxidative stress
  • Superoxide dismutase
  • Ubiquinone
  • Vitamin E

ASJC Scopus subject areas

  • Dermatology

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