TY - JOUR
T1 - Increased sensitivity to peroxidative agents as a possible pathogenic factor of melanocyte damage in vitiligo
AU - Maresca, Vittoria
AU - Roccella, Maria
AU - Roccella, Francesca
AU - Camera, Emanuela
AU - Del Porto, Giuseppe
AU - Passi, Siro
AU - Grammatico, Paola
AU - Picardo, Mauro
PY - 1997
Y1 - 1997
N2 - 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.
AB - 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.
KW - Catalase
KW - Free radicals
KW - Oxidative stress
KW - Superoxide dismutase
KW - Ubiquinone
KW - Vitamin E
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M3 - Article
C2 - 9284096
AN - SCOPUS:0030799094
VL - 109
SP - 310
EP - 313
JO - Journal of Investigative Dermatology
JF - Journal of Investigative Dermatology
SN - 0022-202X
IS - 3
ER -