Physiologic or Intrinsic Aging
- Age 25 - 50: Dynamic to static
wrinkle transition - Age 50+: Collagen degradation
decrease in collagen content in dermis
Photoaging or Extrinsic Aging
- All ages
- UV exposure results in photoaging
– Manifests as wrinkles, lentigines, hyperpigmentation
- Sun exposure: responsible for 80% of facial aging – UV radiation directly induces collagen breakdown
Retinol (OTC)
- 20-fold less potent than tretinoin (dermal concentration 1000 fold less than tretinoin)
- Must be converted to tretinoin in vivo to become biologically active
- No significant trials have supported efficacy, in contrast to tretinoin
Tretinoin (all-trans retinoic acid)
- Naturally occuring vitamin A derivative
- Activates all RAR pathways (alpha, beta, gamma)
- Available by prescription only
- Approved by the FDA (Large body of evidence)
Tretinoin Pathway
- Effects are mediated through binding the nuclear
retinoid acid receptor (RARs) localized to specific
chromosomes - alpha (epidermis), beta (dermis),
and gamma (epidermis). - Regulate gene
expression directly on DNA.
Tretinoin Effects
- Increases collagen production: Induces types I and III
procollagen gene expression in human skin - results
increased deposition of collagen fibrils in dermis - Reduces collagen and elastin breakdown by inhibiting
MMPs (matrix metalloproteinases), UV exposure upregulates expression of these collagenases
How does Tretinoin minimize fine lines?
Due to increased collagen
production and collagen breakdown (via MMP
inhibition)
How does Tretinoin even skin tone?
Causing dispersion of the
melanin granules in the epidermis
How does Tretinoin smooth texture?
Adjusting skin histology
(epidermal hyperplasia), increasing GAGs
How does tretinoin decrease acne?
Prevents exfoliated keratinocytes from sticking together, decreased sebaceous gland activity
Peachy retinoid ingredients (4)
- Tretinoin
- HA
- Vitamin C
- Niacinamide
Level 1 retinoid
0.015%
(prior level 1 - 0.015%)
Level 2 retinoid
0.03%
(prior level 2 - 0.025%)
Level 3 retinoid
0.06%
(prior level 3 - 0.05%)
Level 4 retinoid
0.089%
(prior level 4 - 0.1%)
rarely used
Process of photoaging
- UVB radiation damages collagen and elastin (extracellular matrix)
- Drives the wrinkled appearance of sun-exposed skin.
Loss of collagen and elastin
leads to?
Wrinkled appearance
When does photoaging start to occur?
3-5 minutes of UV exposure, long before visible sunburn
What is critical in preventing photoaging?
Sunscreen
Acetylcholine (ACh)
The neurotransmitter that induces muscle contraction
Botulinum toxin A mechanism of action
- Breaks the snare protein to prevent the release of acetylcholine from the presynaptic nerve into the neuromuscular junction.
- By inhibiting neurotransmission between peripheral nerves and muscle fibers, the local skeletal muscle is temporarily denervated, weakened and cannot contract as aggressively
How does botox prevent the progression of dynamic
wrinkles to static wrinkles?
By reducing the amount of muscle contraction, botox
reduces the amount of collagen breakdown and remodeling
Frown lines muscle group
- Corrugator supercilii
- Procerus
- Depressor supercilii
Horizontal forehead frown lines muscle group
Frontalis
