Reducing Sun Damage to Skin

SunshineThe sun is a powerful source of energy and radiation that can be both beneficial and harmful.  It feels so great to get out in the sun, especially after a cold, rainy day, but the effects of too much sun can be incredibly damaging to skin health.  The sunlight’s cellular and molecular effects depend on the radiation energy and penetration.  The spectrum of solar radiation ranges from the shorter wavelengths of UVB and UVA to the longer wavelengths of visible radiation (VIS), near-infrared radiation (NIR) and infrared radiation (IR).  UV radiation has more energy and is more penetrating.  UVB radiation has more energy than UVA radiation.

UVA exposure, however, causes accelerated skin aging known as photoaging or extrinsic aging (as opposed to normal or instrinsic aging).  Photo-aged skin is characterized by deep wrinkling, loss of elasticity, uneven pigmentation, dryness, and rough texture.  The UV-induced degeneration of skin is a cumulative process that depends on the frequency, duration and intensity of exposure, as well as skin pigmentation.  UV radiation and NIR radiation both give rise to the generation of reactive oxygen species (ROS).  ROS play an important role in skin aging due to the fact that aged skin has a decreased ability to neutralize ROS leading to increased oxidative stress. Continue reading

 Reducing Dermal Scarring

Scars are areas of dermal fibrosis that replaces normal tissue after in­jury and during wound healing.

There are several types of dermal scars including:

  1. Atrophic scars that appear as sunken or pitted areas of skin
  2. Hypertophic scars that are charac­terized by raised areas of skin
  3. Keloid scars characterized by growth outside the original wound area
  4. Striae distensae (stretch marks) characterized by linear bands of atrophic-appearing skin.

Dermal ScarringWound healing involves 4 critical phases that overlap: the coagulation phase, the inflammatory phase, the migration-proliferation phase (de­velopment of granulation tissue), and the remodeling-regeneration phase that includes maturation, scar formation and re-epithelialization. The magnitude of the second phase, inflammation, affects the amount of scar tissue that is produced at the conclusion of the healing process. Regeneration is thought of as re­placement of tissue, however, scar formation actually involves a pro­gressive remodeling of granulation tissue. In fact, scars are defined as dermal fibrous replacement tissue that results from a wound that has healed by resolution (rather than re­generation).

Scarring typically occurs following damage to more than 33% of the skin thickness from trauma or surgery. Can skin damaged in this way ever heal without scarring? Actually, com­plete regeneration occurs exclusively in lower vertebrates. Scarless heal­ing in humans only occurs in early embryo development. So, why do we form scars after early development? One theory suggests that wound healing in mammals is optimized for fast healing in a fast-moving, micro­bial-rich environment. Rapid inflam­matory responses may allow quick healing to prevent infections. Continue reading