PROLIFERATION AND PROPAGATION OF HUMAN MELANOCYTES IN-VITRO ARE AFFECTED BY DONOR AGE AND ANATOMICAL SITE

We report the effects of two factors, donor age and anatomical site, on the proliferation and melanization of human melanocytes (MC) derived from (1) neonatal foreskins, (2) adult foreskins, or (3) adult breast or arm skin. Two different growth media have been used for this purpose. Medium I supports the long-term proliferation of neonatal MC, and medium II supports the growth of both neonatal and adult MC. We found that neonatal foreskin MC proliferated equally well in both media for more than 12 passages. However, adult MC behaved differently in the two growth media. In very early passages (passages 1-5), all three types of MC proliferated well and reached comparable final cell densities in medium I, but adult foreskin MC proliferated at a higher rate than neonatal or adult non-foreskin MC in medium II. The non-foreskin adult MC had the least proliferative rate in medium II. Unlike neonatal MC, both adult foreskin and non-foreskin MC underwent a drastic reduction in their proliferative rate after only a few (9-10) passages in culture. While the three types of MC differed in their proliferative rates, they responded similarly to melanogenic stimulation by cholera toxin (CT) and isobutyl methylxanthine (IBMX). These results demonstrate that the proliferation of human MC in standard culture media is affected by the donor age and the anatomical site from which these cells are derived. We conclude that human MC are heterogeneous, and caution must be used in extrapolating the results of studies on MC derived from different anatomical sites or age groups.