All of us can remember times when we looked at a stranger and tried to guess how old they were judging by their appearance. Why do some women look to be over 50 when they might be only 40? Why do some who are 60 look as if they were only 50? Are some people genetically blessed?
What most people don’t realize is that many of the signs can be prevented, and many can now be reversed after they occur. Cellular research and bio-engineering discoveries make it possible to actually control many of these factors to restore a healthy youthful appearance.
Aging is a process that actually begins at the time of conception and continues until death. Our genetic “blueprint” does control our basic features and thus account for having “eyes like your mother” or similar family characteristics. If all of the billions of cell divisions occurring as life goes on could happen without occasional errors in the duplicating process, there would be no aging and thus no change in skin appearance from that of a young child.
The pattern for this duplication is DNA. DNA is a complex protein molecule of two very long “ribbons” of amino acids. Each ribbon has thousands of these amino acids linked in chain-like fashion. Once an embryo is formed, each future cell division is destined to repeat the sequence of cell divisions modeled after the original DNA pattern. Each DNA ribbon is uniquely specific for that individual person.
If a ribbon strand is broken or formed with a single misplaced amino acid in the sequence, some change will occur later on in life. This may be as simple as uneven color patches or may result in cancer formation and growth.
Though repeated cell divisions do have random occasional errors (It would be impossible to make billions of biscuits that would be exactly identical!), the appearance of aging in all of us is caused primarily by external factors causing injury within individual cells resulting in damage to DNA. Over 90% of the damaging changes are due to Ultraviolet light rays from the sun (UV damage) or from smoking. Both of these events are related to formation of chemical free radicals that attack surrounding molecules like microscopic hand grenades.
If we visualize the skin appearance of a young child, we can imagine a number of things. Mind pictures of skin that is soft, smooth, has even coloration, few lines (no wrinkles), and radiant glow to the skin easily come to mind. What then is it that changes over time with our youthful skin to make us look older?
To understand the changes in damaged (older) skin and what can be done to reverse the changes to restore a youthful appearance, we must first examine what the normal skin of a child is like. We must look at the structure and the functions of the skin.
Skin Functions
The skin is an organ itself! It is an impressively large and heavy organ. It occupies between one and two square meters of surface area for the average adult. In children, the skin accounts for a larger percentage of body weight than adults. In adults, the skin can be estimated at 15 percent of total body weight.
The skin is a wall between things within our body and the outside, that if not separated would lead to death in a short time. In a way we can look at the skin as a fence between our house and the rest of the world.
Actually, it is much more complicated than this in that the skin barrier is dynamic. This means it must let some substances pass through from the external to within and likewise, some substances leave from the inside must pass through to the outside. Not only this, but it must be able to regulate when, how much, and where these activities can occur.
In the complex physiology of life, the skin actually has several functions. The first is to be a simple barrier for fluid exchange within the body and the external environment. It is very well suited as a radiator, or cooling system, for the entire control of temperature in the body. A consistent network of small vessels covers the outer core of the body just beneath the skin. These allow heat from chemical (metabolic) processes to reach the skin’s surface and leave. Actual cooling of the body occurs through vasodilation of the skin vessels and the process of sweat evaporation, which has a cooling function that is very efficient.
Another function of skin is related to specialized cell types that allow some protection from ultraviolet light. Melanin is produced by melanocytes. This is the pigment present as sun exposure causes tanning to occur. The skin serves as the mechanism for sensory input to the body. There are specialized nerve structures for pain and temperature perception, light touch, and for stretch or tension changes within the skin. This is done through a series of nerve fibers that terminate in the dermal and epidermal layers with their receptive organs. The skin regulates the immune system and activation of chemical mediators of the antibody system. Lastly, the skin has an important function in metabolism by having a unique ability to mediate and synthesize necessary molecules such as Vitamin D.
Skin Structure
It’s very easy to draw diagrams of skin that delineate the epidermis and dermis, the two distinctly different layers of skin. In realty however, each layer is highly dependent on the other layer to effectively perform its own function. Anything that affects the epidermis will also have an effect on the dermis as a subsequent reaction. Anything that affects the dermis, usually will effect the function of the epidermis. Obviously, most things that affect the dermis without mechanically affecting the epidermis from the outside will be from internal origin, such as a disease process, a blood flow related problem, or other abnormal circumstance. An exception to this is the effect of UVA ultraviolet radiation, which passes from the external through the epidermis and explodes its energy within the dermal structure.
The epidermis is the external layer of the skin and functions as a mechanical barrier to the outside environment. It is the first line of defense to keep out dirt, germs, water, insects and other noxious substances. As a barrier it helps the retention of fluid within the body to prevent the entire organism from evaporation and death. The unique network of epidermal cells and the spaces between them allows moisture to pass through the surface of the skin in both ways allowing the evaporation of sweat to help regulate body temperature.
The dry corneocytes (dead surface cells) provide a toughened outer layer that resists friction, puncture, abrasion, and yet at the same time is sensitive to receptor cell mechanisms that are specialized to recognize the lightest touch or the cooling effect of a soft breeze. As found with all living cells in the body, there is a mechanism for replacement of lost or damaged and dead cells in a complex but very efficient renewal system.
As basal cells divide, the daughter cell moves to the next layer toward the surface pushing the cells above it to a higher level. As the cells migrate upward toward the skin surface, life processes in the cell begin to diminish until as the cells reach the stratum corneum layer the nucleus is completely gone, the cell becomes dry and flat, yet still attached through intracellular bonding primarily consisting of glucose aminoglycans which serve as the “mortar” between adjacent cells.
The stratum corneum cells are continually pushed upward toward the surface and are eventually exfoliated at a rate that allows a relatively constant thickness in the epidermis. Over any short period of time, the thickness varies very little. Cell kinetic studies have shown that in a 14-year-old child the skin cell turnover time overall is approximately two to three weeks.
With increasing age or over several decades, this thickness actually increases as the stratum corneum exfoliates at a slower rate. This decreased rate of exfoliation is responsible for a more haphazard shedding and retention keratosis gives the roughened, flaky texture and appearance to older skin.
Every person will have less than perfect skin coloration at some time in life. That is the nature of life and the effects of sunlight and UV rays over time. To treat patients with uneven, blotchy, or dyschromic skin, it is imperative that we understand a few simple biologic facts about where pigment comes from, how its production is stimulated, which pigment will respond to control or removal techniques. About one percent of epidermal cells are melanocytes.
Melanocytes are pigment-producing cells and may be seen and identified as early as eight weeks in embryonic growth stages in the human. Small organelles within the melanocyte called melanosomes actually produce the melanin and act as the transport “packets” to carry pigment into nearby keratinocytes. Nearly all human skin has approximately the same number of melanocytes per unit area. The difference in pigmentation that determines racial types is in the number of melanosomes that produce the pigment. and the method of dispersion of pigment granules as they are secreted from the melanocyte into the surrounding skin cells.
As exfoliation occurs naturally, melanin pigment is shed as it reaches the surface. The production of melanin itself is a complex multi-step process that involves a number of different enzyme actions:
Tyrosine > DOPA > + Copper ions + Enzymes > Eumelanins > Melanin
Normal skin tone is due to a constant, even production of melanin. Stimulation by UV in increased sun exposure increases the rate of formation of pigment granules to create
“suntan”. Without continued excess stimulation by UV, the tan slowly fades over a period of several weeks as the melanin-containing keratinocytes go through the process
of normal exfoliation and shedding.
The production of abnormal blotches of pigment are commonly the result of the sun-induced pigmentation discrepancies related to sun damage within individual melanocytes or groups of melanocytes in the basal layer. Exposure to the sun causes these melanocytes to form abnormal amounts of melanin produced in relation to adjacent areas. Other stimuli such as hormone imbalances, drug interactions, and localized skin trauma from peels, burns, or other injury easily can cause melasma, darkened blotches, called post inflammatory hyperpigmentation.
Pigment caused by sun damage may be removed. The various skin-bleaching agents that one may apply topically do not bleach the skin, but rather selectively interfere with the enzymatic processes involved in the production of melanin to block its production.
The two most powerful agents are Hydroquinone and Kojic acid. They each act at different steps in blocking the production of melanin. Thus they may be combined to get greater pigment suppression. Once hyper-production is controlled, exfoliation allows the melanin to disappear as the stratum corneum layers peel and shed off the surface taking the melanin pigment granules away.
My preference for melanin suppression is a combination of 2% hydroquinone plus 3% kojic acid applied topically twice daily. Theraderm Enlighten is formulated to achieve maximum suppression of new pigment and avoid any skin irritation. Enlighten is prescription strength, but available online www.theraderm.net without prescription. Clear even pigment should be noticeable in 8-12 weeks as the existing pigment excesses wear off. Continue using Enlighten twice daily for three weeks after the pigment has decreased for best results.
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