The two lines of defence
against skin aging
coming your way.
It is well known that UVR causes a great influx of free radicals, even the energy produced by the conversion of ADP in ATP creates free radicals. In fact just staying alive creates free radicals. Without the body's built in anti free radical protectors, especially super dimutase oxide, Vit C & E, the aging process would be far more rapid than it is.
The body's ability to repair and protect it self is amazing.
Even if death is programmed into both cellular and multicellular locations, increased free-radical activity from environmental sources or loss of natural anti-oxidants could be expected to dramatically accelerate the aging process.
The prevention of free radical formation is therefore a critical process in any cellular environment no matter what the age of the cell or organism with which the cell resides.
The aging process in skin is intimately related to the acute and chronic control of free radical formation.
This is what we call the first line of defense
The First Line of Defense
The body has many antioxidant defenses, many of which you know. They are classified in many ways.
I prefer to separate them into two major groups
The protein & enzyme group
Protein - transferrin, ferritin and ceruloplasmin. These are proteins that bind metals in the blood stream.
Enzymes - superoxide dismutase, catalase, glutathione peroxide, glutathione transferase, thio-specific peroxidases and others.
and the vitamin& metabolite group.
Vitamin - ascorbic acid, tocopherol and retinol - Vit C, E and A respectively.
Metabolites - bilirubin, uric acid, glutathione, nicotinamide, dinucleotide, phospate complex, magnesium, manganese, zinc and lipoic acid.
Recent findings indicate the first molecular line of defense against free-radical lipid peroxidation damage in the body involves water soluble vitaminL-ascorbate (i.e., in salt form at physiological pH values).
Even in the presence of high levels of Vitamin E, in vitro experiments indicateL-ascorbate is consumed first because it reduces the atocopheroxyl radical back to atocopherol.
This can also be accomplished to a lesser extent by cysteine and glutathione.
A new antioxidant to consider from the metabolite group
Alpha Lipoic Acid
Alpha lipoic acid is a unique free radical protector for all cellsbecause it is the only such nutrient which is both fat and water-soluble, Therefore, alpha lipoic acid has excellent bio-availability and can easily travel across cell membranes to fight free radicals both inside and outside the cell.
This is unlike many other antioxidants, vitamins C and E are too large to pass through the cell membrane and thus offer protection only on the outside of the cell. Alpha lipoic acid, on the other hand, is a very small molecule which can easily pass through the cell membrane, providing free radical protection both inside and out. Because alpha lipoic acid works both inside the cell and at the membrane level, any free radicals that make it past the first line of protection are combated right in the cell itself.
But alpha lipoic acid's benefits expand far beyond its antioxidant activities. Most notably, alpha lipoic acid is first a coenzyme in the metabolic process and is necessary for the conversion of glucose to energy (ATP).
Alpha-lipoic acid (also called thioctic acid) works together with other antioxidants such as vitamins C and E. It is important for growth, helps the body produce energy, and aids the liver in removing harmful substances from the body. Alpha-lipoic acid (ALA) also prevents cell damage, controls blood sugar, and removes toxic metals from the blood.
Alpha-Lipoic Acid is a remarkable metabolic antioxidant readily transported through cellular membranes. It also helps recycle other antioxidants! What this means is that when vitamin E quenches lipid peroxidation a vitamin E radical is formed and that radical is reduced back to vitamin E by lipoic acid. It does a similar task with vitamin C, in turn Vitamin C can also reduce vitamin E.
The Second Line of Defense
Repairing or Removing Damaged Proteins
One way to combat aging, scientists believe, is to trap damaging agents before they can do the body harm. At the top of researchers' list of biochemical outlaws is the group of chemicals called free radicals. Some of these extremely reactive compounds hail from environmental sources, such as radiation and smog, but the bulk are generated as byproducts in the body's normal course of converting sugar and oxygen to energya job performed in every cell by structures called mitochondria. Thousands of these tiny powerhouses wander through cells' interiors, leaking free radicals that burn holes in membranes and leave hot spots of so-called oxidative damage in their wake.
Free radicals mangle not only vital protein enzymes and molecules carrying the genetic code but also the energy-generating mitochondria themselves, half of which may be dysfunctional by old age.
Repairing or Removing Damaged Proteins
The body is made up largely of proteins. The health of the body's stock of proteins depends upon its freedom from damage (as through oxidation or cross-linking), and upon its timely removal as part of normal protein turnover.
The body's antioxidant system and other lines of defense cannot completely protect proteins. Nature's second line of defense is the body's system for repairing or removing damaged proteins. While some protein repair mechanisms exist, there are no known ways to repair most protein damage, including even simple oxidative damage to the amino acids which are the building blocks of proteins. Thus it is essential for the body to efficiently remove aberrant and unneeded proteins, a process called proteolysis.
Proteolysis removes damaged proteins before they do significant harm, and removes undamaged proteins before they become damaged or disruptive.
For example, if oxidized proteins are not broken down, they tend to cross-link and aggregate creating wrinkles.
Rapid effective proteolysis is therefore an anti-aging mechanism.
The main proteolytic enzyme complex is called the proteasome.
It removes proteins that have been tagged for degradation by a peptide called ubiquitin.
Through its role in protein disposal, the proteasome-ubiquitin pathway helps regulate many basic cellular processes including:
cell cycle and cell division,
cellular metabolism and DNA repair.
Thus a malfunctioning
proteasomal system has far-reaching consequences.
A vicious circle develops of age-related decline in proteasomal activity, age-related increase in protein carbonylation and further inhibition of the proteasome. The life cycles of proteins become blocked, and the normal turnover of protein declines.
Is there a way to block this vicious circle?
The body contains a dipeptide called carnosine that both protects proteins from carbonylation and helps reverse proteasomal decline.
Carnosine is a multifunctional dipeptide made up of a chemical combination of the amino acids beta-alanine and l-histidine. Long-lived cells such as nerve cell and muscle cells contain high levels of carnosine.
Carnosine addresses the biochemical paradox of life: the elements that make and give lifeoxygen, glucose, lipids, protein, trace metalsalso destroy life in ways that are inhibited by carnosine.
Carnosine protects against their destructive sides through potent antioxidant, anti-glycating, aldehyde quenching and metal chelating actions. A prime beneficiary is the body's biggest targetits proteins.
The body is made up largely of proteins. Unfortunately, proteins tend to undergo destructive changes as we age, due largely to oxidation and interactions with sugars or aldehydes.
These interrelated protein modifications include oxidation, carbonylation, cross-linking, glycation and advanced glycation end product (AGE) formation.
They figure prominently not only in the processes of aging but also in its familiar signs such as skin aging, cataracts and neuro degeneration. Studies show that carnosine is effective against all these forms of protein modification.
As an antioxidant, carnosine potently quenches that most destructive of free radicals, the hydroxyl radical, as well as superoxide, singlet oxygen and the peroxyl radical.
Surprisingly, carnosine was the only antioxidant to significantly protect chromosomes from oxidative damage due to 90% oxygen exposure.
Carosine's ability to rejuvenate connective tissue cells may explain its beneficial effects on wound healing. In addition, skin aging is bound up with protein modification.
Damaged protein accumulate and cross-link in the skin, causing wrinkles and loss of elasticity.
Is Carosine the answer to this problem?