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The Organized Chaos of Biological Mechanisms
By: Johann W. Wiechers, PhD, JW Solutions
Posted: April 17, 2009
page 2 of 3
I recently finished writing a chapter for the book “Aging Skin: Contemporary Knowledge and Future Directions” that will be published shortly by Allured Business Media. The editor is my friend Linda D. Rhein, PhD, former president of the Society of Cosmetic Chemists. She asked me to write a chapter on the mechanisms of skin whiteners. I accepted the invitation and signed the necessary paperwork in which one promises to submit one's work on time, although I never do for the simple reason that my life is too chaotic, a euphemism for saying that I don’t plan properly enough. When writing a chapter, I need some structure, my "coat-hanger," to be able to explain what I want to say. I looked at all the different mechanisms from various angles; from a physical side, a chemical perspective, an enzymatic side and a physiological angle. But a clear answer did not present itself. A clear-cut subdivision of the mechanism of skin whiteners was not possible, regardless of the viewpoint.
It is common knowledge that tyrosinase inhibition is involved in skin whitening. Tyrosinase is the enzyme that catalyzes the rate-limiting first two steps of the skin melanogenesis process. Both eumelanin and pheomelanin production are reduced when blocking this enzyme. This is clearly an enzymatic mechanism and it is not hard to find a few more, such as tyrosinase related protein (TRP) 1 and 2. Another mechanism of action of skin whiteners is a hormonal one, involving different hormones where melanocyte-stimulating hormone (α-MSH) is probably the most well-known representative. A third mechanism of skin whiteners is a strictly chemical one where copper ions are extracted from the tyrosinase enzyme, rendering them inactive. A fourth mechanism of skin whiteners is a biochemical or molecular biological one, where a whole series of growth factors are involved in inducing changes in skin melanogenesis. The fifth mechanism of skin whiteners is where this beautiful ordering of the various mechanisms of skin whiteners starts to fall apart. This is the physical mechanism of skin whiteners. A sun tan, for example, is nothing more than an inflammatory reaction to sunlight. It is the product of a physical effect (sunlight), resulting in a biochemical effect (the up-regulation of interleukin-1α (IL-1α)), which induces enzymes (tyrosinase) to work harder and steers a physiological effect (melanin being transported to the dendritic ends of the melanocyte and taken up by neighboring keratinocytes) to create a suntan. Although this may all sound rather chaotic, these processes are all strictly regulated and definitely not random.
Melanin is not the only chaotic process that is highly regulated. Skin barrier formation has a lot of order in that chaos, too. In June 2009, Cosmetics & Toiletries magazine will publish an article in which I describe a new mechanism of skin moisturization, the stabilization of the orthorhombic skin lipid phase. But again, this biophysical mechanism is only one aspect of skin moisturization. One can also improve skin barrier function and, therefore, skin moisturization via enzymes, chemistry, biochemistry and molecular biology.
I now am starting to ask myself whether chaos is the right word. The borderline between chaos and order is very slim. Many would call my office extremely chaotic, but for others (mainly with a similar office) this is normal. Mechanisms of action of active ingredients may be complex and therefore seem chaotic, but once someone is knowledgeable about them, order can be established in this chaos and only then, this chaos comes to life. This dynamic, vibrant life is what we want after all; what may be considered a chaotic life where we are in full control. There’s definitely more order in this chaos of ours than we think.
My friend Gavin Greenoak, PhD, from the University of Sydney and the next president of the IFSCC, sent me a picture of nebulae in the middle of the Milky Way galaxy. If you look carefully, you can see an 80-light-years-long double helix structure. Come to think of it, a cell resembles a solar system.