Genetic testing and cosmeceuticals: hope or hype?

Key Points

Don't forget to fill out the questionnaire with your age, sex, skin type, skin color, eye color, amount of sun damage, sun protection practices and ethnicity. In about three weeks, you will receive in the mail a box of skincare products developed specifically for your unique genetic makeup.

Is the result great genetically designed skincare products, or simply a joke? This is part of the controversy regarding the new "gene" approach to skincare. Was the skincare product developed based on the consumer-provided questionnaire data, or genetic analysis of the buccal swab?

It is interesting to note that analysis of genetic material does not always tell the whole story. Each of us is a mosaic with a maternal and paternal genetic contribution. While we have two genes for every characteristic, only one gene can be expressed. The same gene is not always expressed even in the same tissue. For example, certain areas of the scalp seem to gray preferentially over others. Is there a different clone of hair cells at the temples versus the occipital region?

Another example of genetic variation is observed in the predilection for photodamage among persons of Fitzpatrick skin types IV and V. Some persons with type IV skin and extensive photoexposure have malar lentigines, while others with type IV skin and extensive photoexposure have no facial freckling.

If both people have type IV skin, what is the difference? Obviously, the melanocyte response to UV radiation is somehow different between these two individuals of the same skin color. Evaluating the family tree of the two individuals reveals that the type IV person with malar lentigines has some ancestors of Irish descent. Thus, even though melanin production yields a Fitzpatrick skin type IV appearance, the tendency toward freckling may represent the expression of some genes more commonly present in Fitzpatrick skin type I individuals.

Genomic benefits

Since all of us are a genetic mosaic, how can a genetic analysis of an individual predict the composition of skincare products without an understanding of how the skin functions on a day-to-day basis in terms of sebum production, photosensitivity, etc.?

Yet genomics has done a great deal to aid in the development of skincare products. Gene analyses of sun-protected young skin, sun-protected mature skin, sun-exposed young skin and sun-exposed mature skin have been valuable in the decoding of changes in gene expression with aging.

The upregulation and downregulation of collagenase, interleukins, matrix metalloproteinases and prostaglandins has helped us to better understand intrinsic and extrinsic aging. This type of genomic analysis provides a cellular understanding of aging, creating targets for cosmeceutical ingredients.

Once the targets have been identified, genomics can be used to investigate the effects of various topical agents on aging skin. For example, green tea polyphenols can be placed on a cultured skin model, and the culture media removed and placed on a gene chip. The gene chip can then be used to determine the effect of the polyphenols on upregulation or downregulation of factors associated with aging.

Looking to the future

Bioinformatics must be used to wade through the data multitude to determine the cellular effects. Subsequently, clinical studies must be performed to ensure that the cellular effects translate into observable benefits. The gene chip is indeed a valuable research tool for the screening of cosmeceutical ingredients.

Genes, genetic analysis, gene expression and gene chips are all valuable tools in dermatology for understanding how skin ages and directing new ingredient development. Genes may hold the future for dermatology, but the data must be properly used and intelligently interpreted, or the results will certainly be a joke.

Zoe Diana Draelos, M.D., is a Dermatology Times editorial adviser and consulting professor of dermatology, Duke University School of Medicine, Durham, N.C. Questions may be submitted via e-mail to zdraelos@northstate.net
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