We hope we don’t lose you with our references to last decade’s sci-fi, but we just couldn’t resist. The quotes are just too juicy, and altogether relevant to the BFT quest.
Trinity: I know why you’re here, Neo. I know what you’ve been doing… why you hardly sleep, why you live alone, and why night after night, you sit by your computer. You’re looking for him. I know because I was once looking for the same thing. And when he found me, he told me I wasn’t really looking for him. I was looking for an answer. It’s the question that drives us, Neo. It’s the question that brought you here. You know the question, just as I did.
Neo: What is the Matrix?
Trinity: The answer is out there, Neo, and it’s looking for you, and it will find you if you want it to.
So….What is the Matrix? (in skin care terms) The stuff produced by cells (generally fibroblasts) and secreted into the environment in which the cells are embedded; contains collagen, proteoglycans, glycosaminoglycans, fluid, cytokines & all sorts of biochemical which can influence the behavior of nearby cells.
The principle component of matrix in skin is collagen. Collagen is in fact the most abundant protein found in mammals and makes up 25 to 35% of total protein content of the body. Tough bundles of collagen called collagen fibers are a major component of the extracellular matrix that supports most tissues and gives cells structure from the outside, but collagen is also found inside certain cells. It is nearly ubiquitous in the body – strengthening all but the tiniest blood vessels, playing a major role in most tissue development, and in its transparent crystalline form, even comprising the cornea and lens of the eye. In contrast to globular proteins such as enzymes, the protein of most collagen exists in elongated fibrils that provide great tensile strength to the fascia, cartilage, ligaments, tendons, intestines, bone, inter-vertebral discs and connective tissue of the inner layer of the skin, the dermis.
Along with soft keratin, collagen is responsible for the strength and elasticity of the skin and its degradation leads to the wrinkles that accompany aging. The fibroblast, the largest population of cells in the dermis, is the most common cell that creates collagen. Collagen makes up from 70% to 80% of the dry weight of the skin.
Historical importance of collagen
The Greek word for glue is koll and the word collagen means “glue producer”. It refers to the early process of boiling the skin and sinews of horses and other animals to obtain glue. Collagen adhesive was used by Egyptians about 4,000 years ago, and Native Americans used it in bows about 1,500 years ago. The oldest glue in the world, carbon–dated to be more than 8,000 years old, was found to be collagen—used as a protective lining on rope baskets and embroidered fabrics, and to hold utensils together. Animal glues are thermoplastic, softening again upon reheating, and so they are still used in making musical instruments such as fine violins and guitars, which may have to be reopened for repairs, an application incompatible with tough, synthetic plastic adhesives which are permanent. Animal sinews and skins, including leather, have been used to make useful articles for millennia. Well preserved historical artifacts with collagen have be found only in dry climates as collagen undergoes hydrolysis over time resulting in gelatin, the same gelatin in Jello, which is colored, sweetened, flavored hydrolyzed cow skin…yum.
Chemistry and synthesis of collagen
Collagen is a composed of a triple helix, which generally consists of two identical polypeptide chains and an additional chain that differs slightly in its chemical composition. Synthesis starts with a three dimensional single stranded structure called procollagen that is assembled with the amino acids glycine and proline as principal components, with Vitamin C having an important role in this process. The triple helix structure results from substitution of the hydroxyl group for a hydrogen atom in the proline residues at certain points in the chains converting them to hydroxyproline. The hydroxylation, next, of the amino acid lysine into hydroxylysine creates the cross-linking of the triple helices into the fibers and networks found in tissues. The amino acid composition of collagen is atypical for proteins, particularly with respect to its high hydroxyproline content.
The synthesis of collagen occurs inside and outside of the cell. It begins with certain DNA genes within the nucleus coding messenger RNA which enters the cytoplasm where pre-pro-collagen is then created. This is enzymatically converted into the triple helix, procollagen, that is transported to the surface membrane of the cell is specialized transporters known as secretory vesicles that are “jettisoned” at the cell membrane into the extracellular space (the space between cells). Once outside the cell, membrane bound enzymes known as collagen peptidases, remove the “loose ends” of the pro-collagen molecule leaving tropocollagen. Lysyl oxidase, an extracellular enzyme, produces the final step in the collagen synthesis pathway. This enzyme acts on lysines and hydroxylysines producing aldehyde groups, which eventually undergo covalent bonding between tropocollagen molecules. This polymer of tropocollogen is known as a collagen fibril.
Now that we have our collagen fibril, let’s see what happens to it.
28 Types of collagen!!
More than 90% of the collagen in the body is Type I (which is one of the principle types found within the dermis of the skin) but there are actually 28 distinct types. The higher you go in number, the weaker is the collagen. The five major types are:
- Type I is the strongest and is located in bones, skin, tendons, fascia, cornea, teeth and mature scars. Up to 90% of collagen is Type I.
- Type II has a little less strength and is in cartilage, vitreous humor of the eye, and the nucleus pulposus of the intervertebral disc in the back.
- Type III is weaker still and is present in granulation tissue, embryonic tissue, the uterus, blood vessels, and keloids (thickened, hypertrophic scars.)
- Type IV is the weakest, supports single rows of epithelial cells, and is found in basement membranes of the surface and interior of hollow organs and blood vessels. Being comprised of different sub-units, the basement membrane also has collagen Types III and VII.
- Type V is found on cell surfaces, in hair and the placenta.
Disorders of collagen can be dramatic and devastating, genetic or acquired
Genetic abnormalities can affect the synthesis of collagen in different ways. In Ehlers-Danlos syndrome, aberrations occur in either Type I or Type III collagen. Depending on the particular mutation, the severity of the syndrome can vary from mild to life-threatening. While hyperflexibility of joints and hyperelastic skin are the most visible manifestations, effects on internal organs can lead to intestinal, uterine, or heart valve rupture.
A variety of autoimmune diseases also target collagen – rheumatoid arthritis, systemic lupus erythematosis, and scleroderma are most notable. Some bacteria and viruses have virulence factors which destroy collagen or interfere with its production (e,g necrotizing faciitis, clostridium.)
Scleroderma(“hard skin”) causes excessive collagen deposition (Type I) that can also affect the lungs, esophagus, blood vessels, and other organs.
OK, now that we know what can go wrong, what happens to the skin when things go right?
Aging of the skin occurs through genetic (intrinsic) and environmental (extrinsic) processes. The skin pays the price by becoming less flexible and elastic through the decades. The major part of the process is progressive replacement of more pliable, resilient Type III collagen with stiffer, less elastic Type I collagen. The table below illustrates the quantitative changes that occur.
Type I and Type III collagen content in normal skin (mean ± s).
Type I collagen (µg/g)
Type III collagen (µg/g)
264.71 ± 5.88
278.87 ± 6.18
0.95 ± 0.03
279.12 ± 7.65
123.27 ± 5.30
2.27 ± 0.13
241.79 ± 8.23
98.41 ± 5.58
2.46 ± 0.15
209.50 ± 14.31
71.30 ± 7.41
2.97 ± 0.40
Table from: The content and ratio of type I and III collagen in skin differ with age and injury. African Journal of Biotechnology Vol. 10 (13), pp. 2524-2529, 28 March, 2011
The table shows that two phenomena are in play: The amount of Type 1 collagen is decreasing through the decades but not nearly as precipitously as the reduction in Type III collagen. Thus the stiffer, tougher, less elastic collagen predominates more and more through the years as the ratio of Type I to Type III collagen increases from 0.95 in the fetus to 2.97 in the elderly. In addition, the total amount of collagen decreases from 543.5 µg/g in the fetus to 280.8 µg/g – a reduction of over 50%. No wonder we wrinkle!
Understanding collagen types is critical to anti-aging therapy. Chemicals that stimulate collagen synthesis affect different collagen types differently. More on this later.
Vitamin C and collagen
As mentioned previously, Vitamin C (ascorbic acid) is a indispensible co-nutrient in the production of collagen. Ascorbic acid is a necessary cofactor for the enzymes prolyl hydroxylase and lysyl hydroxylase which are responsible for the hydroxylation of the proline and lysine amino acids in collagen. Hydroxyproline and hydroxylysine are important for stabilizing collagen by cross-linking the pro-peptides of pro-collagen. The reader is likely aware of the antioxidant nature of Vitamin C which is related to its ability to donate electrons easily, the same chemical function it plays in hydroxylation reactions.
Scurvy, the condition that develops when Vitamin C is deficient, notoriously plagued seafarers in bygone eras when fresh produce was unavailable for weeks and months on end. In fact, the chemical name for Vitamin C is ascorbic acid which has its root in the Latin name for scurvy, scorbutus. Scurvy is a serious, painful and ultimately fatal disease because defective collagen prevents formation of strong connective tissue. Gums deteriorate and bleed, with loss of teeth; skin discolors, and wounds do not heal.
So, what can I do about my skin? Can I do anything about the loss of collagen?
For those who do not have a medical background, it may make sense that If collagen loss leads to skin sagging and wrinkles, then replenishing collagen either orally or through creams should restore elasticity and health of aging skin. But, it doesn’t work this way. There’s no scientific proof that collagen, applied topically, can penetrate the epidermis. The collagen molecules are very complex and large and would not penetrate, and even if collagen did penetrate, it would not be able to incorporate itself within the complex collagen structure in the skin. As we discussed above, collagen is synthesized in situ within the extracellular space and new arriving collagen will not be incorporated into the pre-existing structure. As far as collagen topical creams are concerned, save your money.
Oral collagen supplementation is similarly futile is impacting dermal collagen production. Digestion of protein results in absorption of amino acids, not complex protein structures such as collagen. Studies have shown there may be improved wound healing with amino acid supplementation but there must be a significant dietary deficiency of protein to see any effect. That is very uncommon in our advanced society with its abundance of food of all types. As far as collagen supplement go, save your money.
So, what does work?
Procedures that physically or chemically remove the surface layers of the skin set the stage for rejuvenation within and from the dermal layer with collagen proliferation a major component. Included in this category are chemical peels, dermabrasion, and laser ablation.
The exact mechanisms of nonablative dermal remodeling are still under investigation; however, radio frequency or laser-induced injury to the dermis and/or the dermal vasculature theoretically results in a wound repair response, fibroblast stimulation, and collagen reformation. Radio frequency treatment heats the deeper tissues and laser rejuvenation modalities involve the application of mid-infrared lasers. An increasing body of evidence suggests that lasers in the mid-infrared range may be the best choice for safe nonablative resurfacing on a wide range of skin types.
Dermal rollers have multiple rows of small gauge needles that vary in length and are used to create many tiny perforations of the epidermis in order to promote penetration of topical agents or create subclinical injury to deeper layers to promote a healing response. Longer needles are used by professionals and may require the use of topical anesthesia. Shorter needles can be found in devices for home use.
The is one technique which assures increased levels of collagen but one that is not natural at all– collagen injection. This procedure can fill in a deep furrow or plump a depression but should not be confused with the normal process of collagen deposition as the collagen is never incorporated into the native structure. It is merely a filler. And then there is that collagen lip injection fad of a few years ago. Duck lips. I sure hope none of our readers were tempted beyond their ability to resist.
Topical actives affecting collagen in the skin
There are several actives that can favorably impact dermal collagen when topically applied. Better branded products that are marketed as “anti-aging” products should have some of these included among their ingredients. Actives may benefit dermal collagen through protective effects (principally antioxidant defense) against deleterious assaults from sun or toxin (e.g. tobacco) exposure, or through stimulation of collagen synthesis per se. There is scant research that supports the ability to preferentially stimulate the synthesis of Type III collagen over Type I.
Topical fillers and optical formulations may provide the “look” of smoother skin but the effect is entirely on the surface through the “spackling” of uneven skin geography or optical tricks based on light reflection and diffusion. These are no more than fancy makeup that is gone with the first washing.
Niacinamide (Vitamin B3)
Increased production of collagen based on in vitro measurements, and decreased production of excess dermal glycoaminoglycans.
Retinoids (Vitamin A)
Vitamin A analogs comprise the retinoids and topical application has been shown to be effective in stimulating more rapid cellular turnover in the skin, and to promote synthesis of pro-collagen. (Please see the BFT posting on vitamin A.)
Vitamins C and E
Because free radicals are a major culprit behind UVA-induced skin alterations, application of topical antioxidants would thus seem beneficial and studies confirm their efficacy. One study found that pro-oxidative factors that accelerate skin aging might activate a self-maintained micro-inflammatory process that interferes with skin elasticity and thickness Double-blind studies of topical application of blended aqueous and lipid borne vitamin C compounds showed decreased photoaging scores and increased collagen (Type I) synthesis. Vitamin C demonstrates protective effect against UVA radiation with addition of topical vitamin E showing combined protective antioxidant effect from UVB exposure.
Peptides & Cu++Peptides
KTTKS (a pentapeptide) is itself a fragment of dermal collagen, and stimulates collagen production in fibroblast cultures. At very low levels in culture, KTTKS reduces excess dermal GAG’s. GHK is a tripeptide fragment of collagen. Copper is a required cofactor for activity of lysyl oxidase, an enzyme involved in collagen synthesis. The complex of copper and a peptide (tri or penta) has been examined extensively in the wound healing literature, and shown to be effective at stimulating collagen as well as specific matrix remodeling MMP’s (matrix metalloproteinases). The specific mechanisms have been investigated at a deeper level and found to include induction of cytokines including FGF (fibroblast growth factor) and specifically the beta-3 version as opposed to beta-1. The latter contributes to scarring during healing, while the former has the opposite effect.
A double-blind, placebo-controlled, split-face, left–right randomized clinical study assessing two topical products: moisturizer control product vs. the same moisturizer product containing 3 ppm palmitoyl pentapeptide was well tolerated and provided significant improvement vs. placebo control for reduction in wrinkles/fine lines by both quantitative technical and expert grader image analysis. The National Institutes of Health carried out a rstudy and found pentapeptides increases production of collagen in sun-damaged skin. Subsequent studies have shown when pentapeptides are topically applied; it can stimulate the production of collagen and diminishes wrinkles and lines.
Decorin, a naturally occurring small cellular or pericellular matrix proteoglycan, is a component of connective tissue, binds to type I collagen fibrils, and plays a role cin ollagen fibrillogenesis, regulating excessive bundle-like aggregation of collagen. As skin ages, there is lack of functional decorin, which results in disrupted collagen fibres and in a reduction in the tensile strength of the skin. Two tetrapeptide sequences have been identified as the specific binding sites of decorin to collagen fibrils. These sequences were engineered to generate new tetrapeptides with improved affinity that would present a decorin-like activity. The candidates were screened with an in vitro collagen fibrillogenesis assay and the tetrapeptide with International Nomenclature of Cosmetic Ingredients (INCI) name Tripeptide-10 Citrulline achieved the best results. Like decorin, this synthetic tetrapeptide proved, through in vitro tests, to regulate collagen fibrillogenesis and to influence the diameter of collagen fibres, making them thinner and more uniform. .
Palmitoyl Tetrapeptide-7 is a synthetic peptide comprised of four amino acids whose sequence is SSNA. Palmitic acid is attached to the peptide chain as a penetration enhancer to drive the peptide through the stratum corneum. PT-7 was formulated with the goal of suppressing the body’s production of excess interleukins, cytokines which trigger the body’s acute inflammatory response which leads to glycation damage. Remember, there are good cytokines and bad cytokines when it comes to scar free healing, and rejuvenation.
Coenzyme Q10 ( Nano-Lipobelle H EQ10 / Idebenone)
Coenzyme Q10 is a potent antioxidant able to penetrate into the viable layers of the epidermis and reduce the level of oxidation from UVA radiation. CoQ10 is also able to significantly suppress the expression of collagenase in human dermal fibroblasts following UVA irradiation. These results indicate that CoQ10 has the efficacy to prevent many of the detrimental effects of photoaging. Nano-Lipobelle H EQ10 is an enhanced penetrating modification based on liposome technology and Idebenone is a synthetic analog.
Phytessence Wakame (Japanese sea kelp)
This Japanese sea kelp contains an inhibitor of hyaluronidase, the enzyme that breaks down hyaluronic acid, and hence is protective of hyaluronic acid. The fetal wound matrix, which in contrast to adult skin, does not scar during healing, is rich in hyaluronic acid. In addition, topical hyaluronic acid has been associated experimentally with a reduced amount of scarring in postnatal wound healing. Hyaluronic acid extracted from human skin and scar tissue is associated with collagen and other proteins. In protecting hyaluronic acid from hyaluronidase, collagen scaffolding may be prevented from damage.
Topical estradiol and soy isoflavones
Collagen, elastin and dermal hyaluronic acid appear sensitive to and dependent on hormonal levels as hormone reduction produces skin dryness and losses in elasticity and volume. Some studies show woman’s skin can lose up to 1/3 of its collagen within five years of menopause. Because of possible systemic effects including increased risks of breast cancer, cardiovascular and thromboemboembolic disease, topical hormone application, rather than systemic administration, is recommended when skin effects are specifically targeted. . Evidence also suggests estrogens are stronger antioxidants than Vitamin C and E and that female face and chest skin are especially estrogen-receptive. Estrogen normally works by signaling genes in cells to be switched on or off, however one recent study has found that sun-damaged skin isn’t improved by topical estradiol(Topical 17-beta estradiol in ethanol/propylene glycol (ETOH/PG). Because photo-aging is superimposed on natural aging in sun-exposed areas of the skin, the results suggest that alterations induced by long-term sun exposure hinder the ability of topical estradiol to stimulate collagen production in aged human skin. Soy beans are rich in phytoestrogens that function as selective estrogen receptor modulators producing physiologic responses similar to natural estrogens. Plant derived isoflavones are therefore useful in topical applications to obtain estrogenic effects yet not so well absorbed as to pose a risk to male useage.
Growth factors and cytokines
In a very real sense, the “final common pathway” for stimulus of collagen production, as well as its timing, quality, and the type of collagen it will produce, is mediated by cytokines. To understand the role of cytokines, we should review their function in collagen biology, and in the skin in particular. Like with most things having to do with dermal regeneration, most of our knowledge derives from studies of wound healing.
Recall from other BFT posts that cytokines are the “chemical messenger” molecules manufactured and sent out (expressed) by some cells to communicate with other cells. Growth factors are a particular class of cytokines whose principal characteristic is to induce growth and proliferation in target tissues. Turns out however that growth is a very complicated topic. The table below gives a brief summary of various cytokines and growth factors involved in wound healing. Note that different cytokines predominate in different stages. The story in rejuvenation is much the same, but not divided into these phases. However, similar to wound healing, there is a cleanup phase (get rid of old collagen), a regenerative phase, and a remodeling phase.
There is evidence that applying certain cytokines to skin (e.g. TGF- β1,) are effective in reducing the visible signs of aging. However, it may also induce the wrong phase of healing and lead to scar tissue formation. TGF- β3, on the other hand, suppresses scar tissue formation. Even within the same cytokine family, minor variations of cytokine structure can have markedly different functions.
Other growth factors such as TGF-α, EGF, FGF, IGF-1, and PDGF have been examined for their effects on dermal regeneration. There are also examples of mixtures of cytokines derived by natural means, such as extraction from a culture of fibroblasts in the laboratory (e.g. Nouricel-MD, Skimmedica).
We won’t go into great detail here about the relationship between cytokines and collagen, as that is the topic of another upcoming post. But one thing we find in a lot of medical literature (be it in the realm of liver disease, heart disease, joint disease) is that inflammation leads to collagen deposition. The collagen produced by inflammation tends to be type I predominantly, and tend to lead to scarring. Note from the table that some of the cytokines growth factors that predominate in early wound healing are inflammatory. There are products that claim to be helpful for inducing collagen that may actually be doing more harm than good. You want those anti-inflammatory cytokines for rejuvenation, otherwise you are adding to the problem, not the solution.
That’s part 1 of our journey into The Matrix. Stay tuned for part 2: Matrix Reloaded – Elastin … coming soon.
Niesler, C.U. & M.W.J. Ferguson. (2001) “TGF-beta superfamily cytokines in wound healing” in TGF-beta and Related Cytokines in Inflammation (Breit, S.N. and S.M. Wahl, ed., Birkhauser, Basel, pp. 173-198.