Orange Roughy Oil for Sensitive Skin and Other Topics: Literature Findings

By: Charles Fox, Independent Consultant

Posted: March 31, 2009, from the April 2009 issue of Cosmetics & Toiletries.

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Skin Pigmentation
The life cycle of melanocytes: Shinpou et al. have reviewed controlling the life cycle of human melanocytes by paracrine factors.⁸ Hyperpigmentation and uneven pigmentation are cosmetic skin disorders that result from the aberrant proliferation and activation of melanocytes. To shed new light on the treatment of these disorders, an understanding of the life cycle of melanin-producing melanocytes would be of interest.

The life cycle of melanocytes includes several steps, beginning with the birth of undifferentiated precursor cells called melanoblasts followed by their maturation to fully differentiated melanocytes, their proliferation and activation, and their eventual death. This process is not fully understood in terms of identification of the precursor cells and the paracrine and intrinsic factors that regulate progress through the life cycle.

In order to identify such factors in vitro, the use of a completely defined culture medium has a major advantage. Researchers in the present study developed a normal melanocyte culture system based on a serum-free, chemically-defined medium to examine the in vitro effects of various paracrine factors on the life cycle of melanocytes with particular attention to their proliferation, activation and cell death.

Facultative skin pigmentation: Jimbow has reviewed aging and skin pigmentation including molecular targets for management.⁹ Skin lightening for antiaging has recently become a large segment of the personal care industry, particularly for ethnic skin.

Skin pigmentation consists of two basic forms: a constitutive skin pigmentation, which reflects genetic skin color; and facultative skin pigmentation that is acquired from senescence and environmental exposure. Abnormal skin pigmentation associated with aging deals primarily with the facultative form, which reflects alterations of an epidermal melanin unit (EMU). The EMU defines the symbiotic interaction of a melanocyte and its associated pool of keratinocytes.