Monday, June 6, 2011

Blast from the past: Photoaging

PHOTOAGED SKIN (original post found here!)

How do we define aging skin? It is skin that has...
  • dermal and epidermal atrophy (sagging, wrinkling, coarseness)
  • reduction in amount of collagen
  • hyperkeratosis (thickening of the stratum corneum)
  • reduced number of melanocytes, Langerhans cells, and fibroblasts
  • shortening of the telomeres on our chromosomes
  • reduction in sebum production
What causes aging? There's the natural deterioration of our bodies as we age - it's theorized this has to do with the shortening of the telomeres on our chromosomes (the specialized structures that shield the end of our chromosomes), but there's nothing we can do about that! It's a genetic thing, and it's the stuff of science fiction that we can play with those telomeres to extend our lives or our appearance. We can control the effects of the external world on the aging process, so let's take a look at our exposure to various chemicals and the sun and how it affects our skin.

Photo-aging is defined as aging due to exposure to the sun. UVA light (longer wavelength, 320 to 340 nm) penetrates deeper into our skin to mess with the keratinocytes and dermal fibroblasts (these are cells that give skin its strength and resilience). It also acts to generate reactive oxygen species in our skin (like the superoxide anion, hydroxyl radicals, and peroxides), which can provoke DNA damage. UVA produces long term actinic damage (the photo-chemical effects of exposure to the sun) and melanin formation or tanning.

UVB light (a shorter wavelength, 280 to 320 nm) can also generate reactive oxygen species, and can damage DNA directly. It contributes to immunosuppressive, mutagenic, and carcinogenic effects of sunlight. UVB light is the main cause of acute sun burn and sun tanning effects - UVA light makes up about 15% to 24% of these effects.

Reactive oxygen species lead to the depletion of skin's natural anti-oxidant system, which causes oxidative stress, which can lead to tissue damage.

Too much sunlight can also result in an inflammatory response, either by sunburn or through overexposure. Inflammation can result in a sunburn - redness, swelling, and pain - or in the break down of collagen, elastin, and hyaluronic acid. Once these are broken down through inflammation, it's really hard to build them back up.

All three can be maintained by use of topical retinoids. Collagen can be maintained by Vitamin C (oral or topical), or copper peptide. Oral glucosamine may help maintain our levels of hyaluronic acid. But nothing can rebuild lost elastin, oral or topical.

Sunburns are particularly awful for our skin. Sunburn is defined as chronic inflammation with the release of proteolytic enzymes of the inflammatory system that disrupts the dermal matrix (collagen, elastin, and hyaluronic acid). The redness, or erythema, is produced by the inflammation.

How do you know if Mr. Sun is the culprit in your skin concerns? Here are a few symptoms (other than a deep sunburn)...
  • actinic keratosis - thick or scaly patches on your skin
  • solar elastosis - vertical creases, deep wrinkles, or loose and sagging skin (thanks to the breakdown of collagen and elastin)
  • yellowing of your skin
  • senile purpura (age spots)
  • solar comedones - small cysts on our skin (treat with acne related products)
  • broken blood vessels - like those found in rosacea type skin
  • extreme dryness, roughness, or laxity of the skin
  • fine or coarse wrinkles (not really all that helpful 'cause we all get these!)
How can we treat aging or wrinkled skin?

Moisturize! Use those oils, butters, humectants, and cationic ingredients to make your skin feel well hydrated and smooth. Our sebum production drops after about age 50, and is almost down to nothing by age 70. Moisturize often and well!

Use surface smoothing agents like quaternary compounds, hydrolyzed proteins, and silicones to treat skin roughness.

Retinoids, topical and oral, can help reverse fine wrinkles, skin pigmentation issues, and rough skin surfaces. But there are lots of lovely side effects to topical retinoids that almost everyone will see such as inflammation, scaling, and redness. (I used prescription Retin-A for quite a few years to help with acne, and it ruined my skin permanently! Not that this will happen to you!)

Alpha-hydroxy acids and beta-hydroxy acids (also known as salicylic acid), which will remove superficial layers of skin to exfoliate. You can also use light exfoliation to accomplish this goal.

Although some studies show that topical anti-oxidants aren't as effective as taking oral anti-oxidants (specifically Vitamin C), we can use Vitamin C, Vitamin E, CoQ10, and the plant anti-oxidants, specifically green tea polyphenols, soy isoflavones like genistein and daidzein, pomegranate oil or extract tannins, and resveratrol in grape seeds. (Click here - emollients - to see more about polyphenols and phytosterols!) 

UV protection is essential! Use at least 15 to 20 SPF every single day! (Read yesterday's post - click older post at the bottom of this one - to learn more!)

Want to know more about the chemistry of our skin and the various skin types, then click here! This is a permanent link at the right hand side of the page under "links to lists". 

No comments: