The aging of our skin can be divided into two broad processes:
Chronological Aging and Photo-Aging.
1. Chronological aging
represents the structural, functional,
and metabolic changes in the skin that parallel the aging and degenerative changes
in other body organs. Symptoms of chronological aging include:
Dry and Thin Skin. While young skin renews itself every three to four
weeks, older skin takes four to six weeks to renew itself. The top layers lose
more moisture due to the aging process, and older skin has a dryer and more
Fine Wrinkles. Diminished production of collagen leads to fine wrinkles
initially observed around the eyes (commonly known as "crow's feet"), forehead,
and other sun-exposed areas. More pronounced effects include furrows at the
site of facial expression lines and sagging folds over the eyelids, neck, jaw,
Abnormal Blood Vessels. Within the many small, delicate blood vessels
supplying nutrients to the skin, abnormalities develop. This is particularly
conspicuous over the nose and cheeks.
Age Spots These are pigmentations that surfaced as a result of a decrease
in the number and function of pigment cells in sun-exposed areas.
Benign and malignant skin tumors due to the deterioration of the skin's
Successful restoration of youthful skin from
this perspective must address a variety of key issues including: collagen replacement,
strengthening the vascular walls of small blood vessels that supply the skin,
increasing vascular supply for oxygenation and detoxification purposes, increasing
immunity to reduce cancer risks, and reducing oxidative damage to the skin.
2. Photo-aging is a separate process and largely involves
damage to the collagen and elastin fibers in the skin. While genetics
play a significant role, the amount of wrinkles present is highly dependent
on the amount of sun exposure. The lines in a "lived-in face," especially for
those who spend a considerable amount of time outdoors, is a consequence of
oxidative damage due to overexposure to ultraviolet (UV) sunlight - both UVA
(responsible for tanning, wrinkling, and melanoma) and UVB (responsible for
sunburn and basal and squamous cell carcinoma). UV light may further damage
skin by increasing the production of proteolytic enzymes that break down collagen,
the connective tissue located beneath the dermis.
Successful retardation of photo-aging can
be achieved by wearing a sunscreen of SPF of 15 or more, and by avoiding direct
and indirect exposure to the sun for extended periods of time.
How Wrinkles Develop
The skin is made up of multiple layers of cells that are constantly going through
self shedding and regeneration once every 30 days or so in repeated cycles.
The layers can be broadly divided into two sections - the top epidermis and
the underlying dermis.
Histological studies of the skin show that a wrinkle is formed following
a series of major cellular changes:
During the sub-clinical phase of aging (from age 35-45), there is a gradual
and progressive slowing of cellular turnover and regeneration. This results
in the skin getting thinner. As a result, the normally undulating ridge-like
dermal-epidermal interface (DEI) becomes flatter. This flatness reduces the
surface area of nutritional exchange between the underlying dermis on the bottom
and the epidermis on top.
Reduced nutrition to the epidermis from aging is one factor that causes
cellular exhaustion and weakness. Without proper nutrition to the epidermis,
cellular metabolism of the epidermal cell is slowed. Furthermore, the transportation
of certain unwanted byproducts of cellular metabolism such as free radical is
reduced. The accumulation of such free radicals within the cell can lead to
undesirable mutational damages in the cell and ultimately cancer.
The adhesion between in the DEI is normally supplied by collagen IV (a multi-sheet
structure or basal layer) and collagen VII (anchored to the sheets structure). The progressive loss of nutrients to this area slows the circulation of
the messengers that serve to promote the neo-synthesis process of such collagen. A vicious cycle is set up. Without an
optimal amount of collagen, the skin sags even more, propagating the dearth
Paradoxically, matured aging skin contains more elastin, which the body
uses to fill in the empty space left by the deficiency of collagen. Such elastin,
unfortunately, is fragmented, calcified, and contains excessive lipids.
In addition to the loss of skin thickness due to lack of collagen support, the
aging skin is more loose and lacks elasticity. These two properties are hallmarks
This process of aging and appearance of wrinkles is accelerated during the clinical
phase of aging (age 45 and higher). By age 50, very few women can escape wrinkles.
The difference only lies in the degree of the blemish.
A wrinkle, very simply, is caused by the
reduction of collagen.
Collagen is a major body protein. There are 19 forms of collagen, and
it accounts for almost 20% of the total protein in our body. In addition
to its critical role in forming support structure of the skin, it is also the
main constituent of the extra-cellular matrix.
Collagen is characterized by its high proline content, which constitutes
about one third of the amino acids. Its triple helix, rope-like structure contains
protein organized in bundles that are anchored to each together at right angles
and held in place by inter-fiber cross linkages.
The most abundant collagen is Type I Collagen.
The spatial arrangement of the collagen network also depends
on the presence of supporting macromolecules known as proteoglycans and glycoaminoglycans
Collagen is a much better support structure
than GAGs.GAGs are a water-saturated gel in which water soluble molecules,
hormones, peptides, and ions circulate. During
the aging process, the diminished amount of collagen is gradually replaced by
the weaker GAGs. This reduction in the quantity of collagen and
replacement with alternative but weaker macromolecules results in skin that
is less thin and less elastic. With age, this gel, due to its weak support structure,
tends to sag, and cellular metabolism and mitosis is compromised. Furthermore,
if water intake is insufficient, the links in the collagen network, like those
of a net cast into the sea, collapse as the net is only "kept open" in the presence
of water and collapses upon itself in a dehydrated environment.
Fibroblasts are mesanchymatous cells within the dermatological meshwork. They
are the basic building blocks involved in numerous mechanisms, including fibrogenesis,
tissue contraction, and tissue skeleton building. They also have a role in epithelial
differentiation, leading to collagen formation. After tissue damage has occurred,
whether it be through acute forces such as trauma, or chronic forces such as
aging, stress, and oxidative damage, the fibroblasts possess an unique ability
to change their phenotype and become myofibroblasts, thereby contributing actively
to the repair process. In the case of wound injury, it would form granulation
tissue to enhance wound contraction and synthesis of macromolecules in connective
tissue such as GAGs.
Researchers have observed for years that fibroblasts in aged tissue do not produce as much collagen. However,
after they have been isolated from their tissue and exposed to endogenous stimulating
factors such as TGFb, they once again produce significant amounts of collagen,
especially Type I Collagen (the predominant collagen in reconstructed healthy
skin) based on a good DEI (where collagens IV and VII are abundant).