The effects of nickel and chromium on human keratinocytes: differences in viability, cell associated metal and IL-1alpha release.

This study was carried out to assess the effects of chromium and nickel upon isolated keratinocytes as an in vitro model of human skin. Keratinocytes were isolated from healthy volunteer skin samples of unknown metal sensitivity (n=10) and were compared with cells from patient biopsies of known metal sensitivity (n=7). Cells were dosed with a concentration range of nickel and chromium (0-10,000 microM) and cellular mitochondrial activity, viability, metal uptake and cytokine release were measured.

Dopa oxidase activity in the hair, skin and ocular melanocytes is increased in the presence of stressed fibroblasts.

We previously reported that mesenchymal cells (dermal fibroblasts and dermal papilla cells) can stimulate dopa oxidase activity in the skin melanocytes. This study extends the investigation of the influence of the fibroblast in a comparative study of melanogenesis in melanocytes from the hair, the skin and the eye. Culture of melanocytes with normal proliferative dermal fibroblasts slightly increased dopa oxidase activity of the hair, skin and ocular melanocytes (by 17, 11 and 28%, respectively), but co-culture with fibroblasts recovering from storage in liquid nitrogen or growth-arrested by means of gamma radiation showed much greater effects.