First Posted on Feb 06, 2016 by Vivienne Bartle
When I first started in the skin care industry as an aesthetician 35 years ago (1981), not much science was around and to try and quence my thirst for knowledge, it was difficult. I however had the best training at the time in a European school with European trained instructors, nurse educators in anatomy and physiology, electrical engineers for the electrical components of our training and a whole host of other specialised instructors. (very different in today’s schools). I also was the highest graded student in the history of the school (97% – made a couple very minor mistakes in practical examination like touching the spine which was a no no in massage back then, seems a little ridiculous now)
Maria, our main instructor, was very passionate about her work and would have us attend other lectures available outside our curriculum – we studied skin cancer, and many health and wellbeing topics, after all this was Queensland – home to body beautiful. Our nurse educator introduced me to the likes of Dr. Bernard Jensen who is a legend for his work with acid/alkaline balance and the bowel is at the core of all disease. The lymphatic system caught my attention as being essential for good health, and I devoured everything I could get my hands on at the time. Fast forward to 2016 and I still study continuously with not only an aestheticians (beauty therapy in Australia) diploma, but also remedial massage, clinical nutrition and a master practitioner level in hypnotherapy. So now it starts to get really interesting, science is catching up and confirming a lot of my previous alternative studies in the areas of nutrition, skin and skin care.
So the purpose of this series of blogs is to educate you a little more on how we age, so that you can easily understand how we can have healthy skin at any age. At Cinergee we are experts in photo-ageing, that demoralising condition that zaps the life and vitality out of your skin and makes you look older than you desire. And yes it involves the sun, from our earliest days on this earth each and every exposure we have is not only affecting our connective tissue (collagen and elastin) but it is contributing to most skin conditions, and what I call the “barnacles of ageing” those precancerous lesions, warty solar keratosis, uneven pigmentation and the like that we see on our senior citizens. Trouble is this is happening now to a much younger generation.
I had a wonderful Mum bring her two daughters into see me today, at 14 and 12 already their skin was being mis-managed. One with sensitive skin and the other dry, they were showing acne lesions stimulated by dehydration, incorrect products and some dietary imbalances – over the next few weeks we will calm and soothe the skin bringing it back into balance so it can start to heal and eliminate the toxin accumulation. Without this intervention – fast forward say 10 years and we have a mess, skin that has aged well beyond their years with increased sensitivity, redness and pigmentation spots and most likely some scarring.
So lets start with the basics – the skin.
Now this might look a little technical but I aim to break it down so it is easy to understand. The skin consists of 3 layers as shown on the left hand side of this diagram.
- The outermost cellular layer is the Epidermis consisting of 5 distinct layers from the Stratum Basale (5th layer) to the outermost dead layer the Stratum Corneum (1st layer) of the skin – see the right hand side of the diagram for other layers – I will be discussing these in more detail shortly.
- The deeper structural layer – the Dermis is broken up into the Reticular layer and the Papillary layer. These layers contain the collagen and elastin fibres as the main structures along with blood vessels, nerve endings and fibroblasts lying in the interstitial fluid. The hair and sweat glands although they originate in the epidermis extend deep into the dermis.
- The Subcutaneous Fat layer (also called the Hypodermis) contains highly organised fat cells that provide the outer two layers an elastic bed and support along with creating surface volume so the upper two layers are smoother and plumper.
The layers of the epidermis are very well organised with an average thickness of around 0.1 mm for all 5 layers (virtually the thickness of a piece of paper – thinner on the eyelids).
The 5th layer – Stratum Basale or Basal Layer – is the only actively living and dividing layer. It is the actively growing stem cell layer from which the epidermis develops. This is also where the pigment (melanin) is found. These stem cells are generally considered undifferentiated (not yet specialised) but when they divide the original cell becomes a specialised keratinocyte and will move up through the layers. The daughter cell however, stays in the basal layer resting for 12 to 19 days before the next cell division takes place and it will then move up. The cells are most vulnerable to UV damage while they are dividing. The time the orginal cell completes cell division and moves up through the layers to the skins surface can take 21 days to 3 months depending on the age of the individual, the health/lifestyle of the individual, and the anatomical area of the skin i.e., the facial skin grows faster in contrast to the skin on the back of the legs.
Due to the constant renewal of the skin, changes can occur in the chromosomes (genetic material) and abnormal cells can be formed. The more the abnormal cells replicate the more distorted the DNA becomes. Luckily we have special cells called Langerhans cells that are immunologically active to select and destroy those cells with abnormal DNA preventing these cells from growing into skin cancers. We also have a built in cell program that causes the death of a cell (apoptosis) which also prevents skin cancers.
Beneath the basal cell layer is the basal or basement membrane which is permeable and allows the basal cell layer to be nourished from the dermis. If you look at the above diagram you will notice that this membrane is not smooth but undulates. The undulations can be from the hair follicle or sweat glands but the wider penetrations into the dermis are from dermal papillae or rete pegs as they are sometimes known. These stabilise the epidermis and fix it to the dermis increasing the surface area. You will also notice that no blood vessels penetrate this membrane so all nutrients that the blood vessels bring, must cross this membrane to feed the basal skin cells. The larger the surface area the more nutrients are likely to cross.
Between all the cells of the skin is a minute space filled with fluid that is important in the nourishment of the skin cells. This fluid contains glycosaminoglycans (GAGS) gel-like combinations of proteins and sugars. As the skin cells migrate to the surface they get further and further from nourishment so it dies.
The 4th layer – Stratum Spinosum or Spiny Layer – so named due to the spiny projections called dermosomes that seem to cause the cells to stick to each other and not be easily shed.
The 3rd layer – Stratum Granulosum or Granular Layer – The cells develop granules called keratohyalin (a pre-cursor to keratin) and membrane coating granules that help with the waterproofing barrier. These are special protein-containing keratin structures and not pigment granules.
The 2nd layer – Stratum Lucidum or Clear Layer – these are usually found only on the soles of the feet and the palms of the hand and the keratinocytes in this layer do not feature distinct boundaries. They are filled with eleidin, an intermediate form of keratin.
The 1st layer – Stratum Corneum or Horny Layer – this is an interesting layer and the most mis-understood of all the layers of the skin by skin therapists. This is the layer where the cells lose their internal structure, become flattened and are by this time filled only with keratin. They progressively loose their adhesions to each other so they can shed in an orderly fashion. In the stratum lucidum and the lowest horny layer there is a natural waterproofing barrier that helps prevent water loss and determines the permeability of the skin.
The barrier consists of lipids in double layers that are extruded from the dying cells and accumulate in the intercellular space to build up the impermeability of the stratum corneum. This barrier is only 0.01 – 0.02 mm thick and is therefore very sensitive to external influences and particularly strained by frequent use of detergents, abrasive products, the sun, weather and pollution. Damage to this barrier can lead to an increased loss of moisture and consequently to dry, scaly skin.
This horny layer is our real protection from the outside world and it is very thin. We need to keep it healthy through the production of good quality protein and very tight binding of the cells together in the layer below. Destroying this layer through microdermabrasions, strong chemical peels or herbal peels doesnt make any sense. Doing this to the skin does not improve skin quality, instead it weakens the skins defences.
Skin Colour
Skin colour depends on the number of blood vessels lying under the basement membrane and the amount of pigment granules in the epidermis. The pigment granules are melanin manufactured by the melanocytes and transported to the keratinocytes (skin cells in the basal layer). Melanin is made by a complex chemical reaction which I am not going to go through but surprisingly we only have two different types of melanin.
- Eumelanin – a dark brown/black pigment
- Phaeomelanin – a yellowish/red pigment
These two are responsible for all the variety of colours we see in peoples hair and skin. The brown pigment is one of the most powerful free-radical scavengers and can deactivate free radicals caused by UV light. Phaeomelanin on the other hand aggravates the effects of the sun which is why people with red hair tend to be more sun sensitive and have a greater risk of skin cancer. When we do a consultation we work out how much of the red head gene you have to determine your ageing or skin cancer risks.
Each melanocyte is connected to surrounding keratinocyes by long fine tubules through which the pigment is transferred. The melanin usually lies on the surface of the nucleus to help protect the DNA from harmful UV rays. When I originally trained the understanding was that the pigment cells were – pigmented. But this is not so, in the melanocyte there is no visible pigment because the chemical precursors of melanin are colourless. Almost immediately after melanin has been synthesized it is tranferred from the melanocyte to other cells and becomes brown or reddish brown.
Because of the melanin in our skin we all have some degree of natural sun protection. It is estimated that people with pale skin (Fitzpatrick type 1) have a natural SPF of 1, type 2 skin is about 1.67, type 3 is about 2, type 4 & 5 have a SPF of about 4, and type 6 skin has an SPF of about 10 to a maximum of 14.
The Dermis
The dermis is thicker than the epidermis at around 1-4 mm and not as organised. The hair follices and sweat glands that originate in the epidermis give some epidermal cover (through epidermal skin cells) when the epidermis is lost through injury or burns. Collagen arnd elastin fibres are the main structures in the dermis, with blood vessels, nerve endings and fibroblasts lying in the interstitial fluid. GAGS – glycoaminoglycans (mainly hyaluronic acid) are an important constituent of the interstitial fluid. These are capable of holding vast amounts of water (like jelly) maintaining turgidity or plumpness of the skin.
The fibroblasts are the most important and only living cells in the dermis. They produce fibres and certain important chemical compounds. The only way to preserve a youthful skin is to activate or regenerate our fibroblasts. Fibroblasts protect collagen by inhibiting collagenases (which decompose collagen) and produce pro-collagenases that destroy old collagen ready to be replaced.
Fibroblasts are biochemically very active and respond to a number of hormones. They have specific chemical receptors which selectively allow oestrogens, androgens, cortisone and cholesterol to be attached to the membrane and therefore penetrate the fibroblast. Vit A and especially Vit C are essential for the production of new healthy collagen. Fibroblasts also produce hyaluronic acid (hyaluronan) which is essential for retaining water in the interstitial matrix and therefore central to the maintenance of skin hydration, cell movement and the multiplying of cells in the dermis. Keratinocytes (skin cells) also produce hyaluronic acid which is important in maintaining epidermal moisture levels.
Hyaluronic Acid
It is important at this point to go into a little more detail about hyaluronic acid. It is a highly visco-elastic polymer of glucuronic acid (a sugar) and glucosamine (an amine) which is why it is labelled a gylcosamino-glycan or GAG. It is an important component of the skin but has a high turnover. Hyaluronan has a major structural function to keep the dermis at optimum volume because of its amazing ability to hold water and cushion cells and structures in a protective gel.
While we are not aware of it, we certainly notice when we don’t have it – we get those bruises associated with thin skin and ageing. The skin becomes drier and fragile, breaking down easily. In the worst case scenario, the bruises may actually kill the overlying skin in a condition called dermatoposis.
The production of hyaluronic acid is initiated by membrane cell receptors which are stimulated mainly by vitamin A, medium length fragments of the acid and keratinocytes. UV damage causes the decay of these receptors and when vitamin A levels are low in the skin (which happens on UV exposure) we have fewer receptors available. We constantly need to replace hyaluronan through adequate levels of vitamin A. Some companies will use hyaluronic acid in their formulations/creams but it is a very large polymer and cannot penetrate the skin even when short fragments are used. At Cinergee we can advise you how to get the best from vitamin A and hyaluronic acid preparations.
The formation of Collagen
An important part of the process is the production of pro-collagen from the fibroblast that then excretes it into the interstitial fluid where it develops into collagen. The command for new collagen comes from chromosomes in the nucleus of the cell. The fibroblast is connected to the collagen by Fibronectin, a kind of glue. When we age fibronectin dimishes and the fibroblast becomes separated form the collagen. Collagen fibres become stiffer with age and are increasingly bound to other collagen fibres.
In order to prevent or delay the ageing process we must promote or maintain the healthy activity of the fibroblast.
Without going into too much detail on other processes in the skin I would like to finish this by summarising what has been covered so far.
SUMMARY
Skin consists of a number of layers that protect the body and give it its characteristic pliability.There are two main layers to the skin: – the outermost epidermis, responsible for waterproofing and physically protecting the body and the innermost dermis which provides the gel structure that cushions and nourishes the tissue including the epidermis. The elastin and collagen framework is in this gel.
In the epidermis the important cells are:-
- The keratinocytes the main growing skin cells which also serve as pigment carrying cells
- The melanocytes – pigment creating cells
- The Langerhans cells which regulate immune response controlling the development of skin cancer and allergic states and detection of microscopic invaders and foreign bodies.
The epidermis is critical for waterproofing the skin and here the “dead” layers play a crucial part. Important for the hydration of the skin, the softness, suppleness and for skin protection.
The dermis has only one important cell: the fibroblast. It is the key cell in maintaining or restoring a youthful appearance to the skin. Structually the dermis is almost totally made up of a hyaluronic-acid-based gel in which the collagen and elastin fibres are embedded.
This will give the basis for the following blogs, understanding a little of the structure and basic chemistry of the skin will help you understand why things can go wrong .
Some of the above information has come from repeated training over the years and some specific details are based from the book Vitamin A Skin Science. I hope you enjoy this series and by learning a little more you will be more equipped to make informed choices for your skin by not wasting your money on miracle cures that simply will not work!
