In this context, cutaneous wounds are thought to heal as a result of the bioelectrically stimulated dispersal of positively charged ions and proteins to the wound site. Thus, it is believed that exogenously provoking this process that guides physiological activity at the cellular level can hasten wound healing by facilitating the transportation of repairing cells to the wound (Nature 2006;442:457-60).
The review article by McCaig et al., cited above, details the cellular mechanisms responsible for the effects of small electric fields on cell behavior, and considers the clinical potential for electric field treatment of damaged tissues, including epithelia (Physiol. Rev. 2005;85:943-78). The use of a 10-mV charge is key in the development of new products.
Acupuncture
Interestingly, the principles underlying these new products are at least tangentially related to the practice, though not the philosophy, of acupuncture in achieving facial rejuvenation. Traditional Chinese medicine has been shown to be effective for such a purpose. Acupuncture needles are inserted along particular meridians to tonify the skin. Such treatments have ameliorated some wrinkles, improved facial muscle tone, and produced better skin texture while reducing facial edema, acne, and sagging in different locations (Aesthet. Surg. J. 2005;25:419-24).
In traditional Chinese medicine, needle insertion along various meridians is believed to move or rebalance Qi (pronounced "chee"), the life force. The question of what Qi is, remains open to debate, says licensed acupuncturist Lynn Bondi, LAc. "Qi could very well coincide with or even be tantamount to bioelectric fields. But I'm more inclined to think that modern scientific measurement techniques are tapping into or quantifying some portion of Qi, which encompasses much more" (personal communication, Jan. 5, 2010). She notes, interestingly, that modern acupuncturist practice sometimes includes the use of microcurrents for facial rejuvenation.
New Products
Products poised to enter the market soon will be touted for their capacity to harness electrical currents to stimulate fibroblasts into synthesizing collagen and elastin. Several products from Johnson & Johnson - Aveeno, RoC, and Neutrogena - contain zinc and copper in a grayish cream that is applied to the skin. Zinc and copper exchange an electron, purportedly generating a 10-mV charge, which, as stated above, is believed to stimulate fibroblasts into producing collagen and elastin. Application of the grayish cream is followed by use of a moisturizer. The water in the moisturizer in turn activates the "zinc-copper battery," thus creating the charge, which the patient cannot feel. Studies have shown increased elasticity of the skin (as shown by cutometer measurements) when this "zinc-copper battery" is used in combination with a moisturizer containing ingredients that have been shown to increase elastin production and assembly.
The process of stimulating functional elastin production is more complicated than stimulating collagen production. In the body, collagen is extracted from fibroblasts in a complete and final triple-helix form. No further change in structure is necessary for the collagen to be functional. Elastin, however, is secreted by fibroblasts as tropoelastin, which consists of unbound units of elastin in an immature form. Elastin must assemble on a microfibrillin backbone in order to be functional.
According to unpublished proprietary data, one of the new Aveeno products contains blackberry, which stimulates fibroblasts to produce tropoelastin, and dill, which has been shown to aid in assembling the tropoelastin "building blocks" onto a microfibrillin backbone to yield mature elastin. Aveeno has sponsored a study in which cutometer measurements showed increased skin elasticity after use of its Ageless Vitality product for 8-12 weeks.
In essence, the theory behind these new products is that the topical delivery of energized zinc and copper stimulates cutaneous electrical cues that coax the fibroblast to produce collagen and elastin. This process may lead to dermal changes that rejuvenate the skin.
Conclusions
I have not been involved in any of the trials of these products and have no firsthand knowledge of these studies. Conceptually, I am intrigued with the idea of an electromimetic current being used to stimulate fibroblasts. I have reviewed the wound healing literature, and the scientific concepts and data make sense.
The notion of harnessing the natural electric currents of skin cells to increase collagen and elastin production is fascinating for several reasons, not the least of which is elimination of the issue of penetration of active ingredients. A charge generated on the cells in the top layer will likely propagate to neighboring cells, eliminating the need for actual penetration of the zinc and copper.
Consequently, an enhancement of cell-to-cell communication would seem likely to extend to the lower layers, allowing the cells deeper in the dermis to "get the message." These products launch in March, and it will be interesting to see how they are received by dermatologists and consumers.