Ageing is one of life’s harshest realities, and is something that we do have to accept! Ageing gracefully is possible, but that doesn’t mean sitting back and letting it happen without putting up a fight! I think we would all like to look a little younger, but much as we would love to believe there’s a quick fix wonder cream out there, I think we all know that is a myth! Dermatologists agree that limiting damage and preventing trauma before it occurs is the strategy that pays off long term. This article is going to help you understand the cause and effect of skin ageing, and hopefully help you make the right lifestyle and product choices, so settle in and make yourself a pot of green tea and read on ……..
The main ageing process is not taking place in the top layers of skin (epidermis) but several millimetres below the surface in the “Dermis”. The slow loss of dermal mass with age, and the resulting or concurrent loss of resiliency, structural integrity as well as skin density, is the most obvious indicators of skin ageing. In addition, muscle atrophy and laxness will follow, in other words saggy skin! great.
In attempts to understand and ultimately affect the ravages of ageing upon skin, we must also deal with the acute and chronic hormonal changes that occur in the lifetime of human skin. Ageing skin is categorised into two parts – Intrinsic and Extrinsic.
We begin by understanding Intrinsic ageing, this is mainly composed of an individuals genetic heritage, and this will dictate the colour of the skin, eyes, hair, in fact everything that makes up the individual. Every cell in the body has the genetic blue print stored in the DNA of the nucleus. This blue print will dictate the exact replication of the cell every time it divides, based on genes that are inherited from the family gene pool. Although genes govern a lot about your skin type, when it comes to ageing, genetic tendencies interact with lifestyle choices to determine how your skin will age. If your mother and grandmother had great skin, you would probably inherited some of their good genes, but if you smoke and bake in the sun then you lower the impact of your good genes and will prematurely age.
Telomeres are small segments of DNA, which coat the tips of chromosomes, and are an important part of that inherited aspect of ageing. Telomeres have been compared with the plastic tips on shoe laces because they prevent chromosomes ends from fraying and sticking to each other, which would scramble an organism’s genetic information to cause cancer, other diseases and death.
These telomeres are critical in cell positioning, accuracy of replication and structural integrity. After some 80 cell divisions the telomere becomes so short that the cells stop dividing and the cell enters a state of senescence (alive but distorted). This process is associated with ageing, cancer and a higher risk of death. So telomeres also have been compared with a bomb fuse. The shortening of our telomeres appears to be the cellular clock that determines the number of times our cells divide , which in turn, appears to control the ageing of our cells. Despite our best efforts that clock keeps on ticking!
Telomerase is an enzyme that repairs damaged telomeres, and has been referred to as the secret to cell immortality. Telomerase can reset telomeres back to their youthful lengths. It is known that most human cells stop making telomerase early in life, (apart from sperm and eggs) therefore creating the biological time bomb that leads to out limited lifespan. This whole process is genetic/intrinsic, the type and life of your telomeres is inherited and out of your control. It is ironic that the only immortal cell is a cancer cell and that brings an end to our life, the reason cancer cells divide forever and do not become senescent is that they contain telomerase.
Wrinkles are one of the end results of an aged skin. It would be fair to say these wrinkles and other skin conditions found in an “aged skin” could easily be reduced in severity by prevention of exposure to Ultra Violet Light and Free Radicals. This is the type of ageing you have control over! and the term “premature ageing” basically means you’ve aged before your time, because of environmental factors, when added to the inherited aspect of ageing will result in how old we look for our age.
The main environmental factor that accelerates human skin ageing is UV radiation from the sun. Sun induced ageing is called “Photo-ageing” and it is a cumulative process that depends on the degree of sun exposure and skin type. Photo-ageing can be influenced further by other extrinsic factors such as smoking, excess alcohol and poor nutrition.
The effects of Smoking
I am sure you are well aware that smoking is bad! and oxidation is one of the main reasons why, the process of the tobacco burning involved in smokers is a major source of Free Radicals (oxidants) in smokers and even passive smokers. Smoking is particularly bad for the skin for two other main reasons. The first is that it interferes with the blood flow to the capillaries – the tiny blood vessels that take oxygen and nutrients to the skin and carry away carbon dioxide and waste products. This inevitably diminishes the health and function of the skin. Smoking also enhances an enzyme in the skin called Matrix Metalloproteinase which results in collagen breakdown and diminished collagen production. The effect causes wrinkles and loss of elasticity, smokers often have quite “loose stretchy skin”. No amount of anti-ageing ingredients will undo skin damage caused by cigarettes. Smoker’s skin is also much more dehydrated that non-smokers and if you continue to smoke you will double the rate at which you age! If you still insist on smoking, then try a little damage control – Improving diet and exercise is essential and replenish the body with antioxidants that are lost by the constant bombardment of Free Radicals. Collagen is damaged by smoking and vitamin C is essential for collagen production, so replenish every day! Seriously though, it’s not just about your skin, think about your internal organs! – give up
Skin Damage: Understanding Oxidation
Free Radicals, oxidative stress and antioxidants are familiar terms in the world of health and beauty, ultimately these terms have more underlying health concerns – ageing, functional decline, illness and fatigue, which I am sure we are all anxious to prevent, to understand more please read – Antioxidants to the Rescue
Changes you will see in your Skin
Both Intrinsic and Extrinsic factors will result in changes to our skin’s structure and funcion, but extrinsic factors cause the more pronounced changes. Some estimates that 80 – 99 % of the ageing we see on our skin as adults is a result of these environmental influences, the exposure to UV light is the major factor.
Intrinsically aged skin is smooth and generally unblemished, there will be exaggerated expression lines on the skin but generally the skin is well preserved. If you looked under the microscope then you will see more signs of ageing, which includes some surface skin degeneration as well as a break down of dermal tissue. In direct contrast, extrinsically aged skin (such as the skin on your face, hands, neck and chest) is wrinkled, sallow in colour and has some hyper and hypo pigmentation. Skin may also show a loss of tone and elasticity, more fragile and with more broken capillaries. Under the microscope extrinsic ageing is evident in the collagen and elastin, which would be thick and damaged – this is associated with cross linking and wrinkle formation.
Wrinkles are basically depressions in the skin’s surface that may be coarse of fine, depending on the depth. Wrinkle depth can vary, coarse, deep set wrinkles are described as expression lines and often appear on the forehead, outer corners of the eyes (crows feet) and as vertical lines on the side of your mouth. Fine lines are much shallower and also appear in areas of facial movement – eyes, mouth and upper lip etc.
Wrinkles occur as a result of a reduction in muscle mass and skin thickness, cross-linking of collagen and elastin and dehydration of the top layer of skin (Stratum Corneum). This results in visible wrinkles on the surface and a loss of strength and elasticity.
Changes in skin colour are often associated with an ageing skin. Skin colour is a mixture of red, yellow and brown coloration. This is a result of red oxygenated haemoglobin, blue deoxygenated haemoglogin, yellow carotenoids, flavins and the brown melanin pigment of our skin. Hyper-pigmentation spots are due to erratic melanocyte activity that is the result of cumulative UV exposure. Also Hypo-pigmentation (white patches) can occur and the result is a mottled appearance made up of darker and lighter areas. The white areas appear due to a reduction in the number of melanocytes, there is a decline of 6-8 % per decade after the age of 30, which accounts for a more translucent skin colour as we get older. As this happens it also reduces the skin’s protective capacity against U.V exposure and along with the decline in melanin, there is also a decline in Langerhans cells, which results in a decreased immune function in the skin, and can account for the increased malignant lesions in an aged skin. When we see an increase in yellow coloration in aged skin, it is a result of a decrease in brown melanin pigment along with a decline in red and blue coloured capillaries. In the case of cigarette smokers, the toxins cause a breakdown of elastin that also contributes to the yellow colour of the skin. This overall skin discoloration if often accompanied by broken veins.
The Breakdown of Collagen and Elastin
The majority of changes that occur in our skin will happen in the Dermis, which can lose 20 – 80 % of it’s thickness as we age. This is the result of changes in Fibroblasts, the cells responsible for Collagen, Elastin adn Glycosaminoglycan biosynthesis. Not only is Collagen and Elastin produced at a slower rate which impacts the skin’s ability to repair itself, but the organization of the proteins also change and affects the structure. The breakdown of Collagen and Elastin is controlled by the activity of Matrix Metalloproteinases (MMP) enzymes, known as Collagenase and Elastase. Studies have shown that U.V radiation activates these enzymes within hours of UVB exposure, and the long term elevation of MMPs results in disorganized clumped Collagen and Elastin that is described as Photo-damaged skin – people who have spent lots of time in the sun! Changes in Elastin fibres are so characteristic in photo-aged skin that the condition is know as elastosis and is a hallmark of sun damaged skin, this is seen as loose skin that takes longer to assume it’s original position when pulled.
Other changes in the Dermis include the ground substance that holds the Collagen and Elastin together, this intercellular glue also undergoes age-related changes. As we age the Glycosaminoglycans such as Hyaluronic Acid diminishes at around the age of 40! The loss of Hyalruonic Acid along with a reduced barrier layer on the surface of the skin is the likely cause of dehydration and the loss of turgidity and fullness, which will add to an aged appearance.
Cell Turnover Slows
Many of the noticeable signs of ageing can be atttributed to a slow down in cell renewal rates and cell turnover time. Studies show that epidermal turnover rate slows from 30 – 50 % between our thirties and eighties! This slow down can account for a dull, rough skin surface in a maturing skin.
The Loss of Fat
Your Hypodermis is a subcutaneous layer, composed of mostly fat (adipose tissue). There is a loss of fat in the facial structure as we get older which contributes to hollows under the eyes and a lack of cushioning over the skull. In this fatty layer the total number of fat cells declines, but they annoyingly accumulate in certain areas resulting in bags under the eyes, double chins and bigger ear lobes!
The Biochemical Reactions that cause Skin Ageing
Scientists attribute the majority of the structural changes in an ageing skin to UV exposure, it has only been in recent years that they have come to understand the actual Biochemical triggers that instigate these changes. These are chemical reactions that occur within the skin and include:
- Generation of Free Radicals, also known as Reactive Oxygen Species, UV light, Oxygen, pollutants etc will generate free radicals from stable molecules. As we have learnt earlier Free Radicals cause a cascade of damage to cells leading to inflamation, cross linking of Collagen and disease.
- Glycation leading to Advanced Glycation End-products (AGEs). When sugar comes in contact with a protein (such as Collagen), it immediately reacts. This generates Free Radicals, which leads to a crosss-linking of Collagen and inflammation. Advanced Glycation End products are formed, and bond with a receptor on the cell to form Receptor-Age (R-AGEs) This causes inflammation, inhibits skin cell growth and contributes to cross linking of Collagen.
- Activation of Matrix Metalloproteinases (MMPs) with a subsequent decline in Collagen biosynthesis. MMPs play a role in maintaining a healthy dermis by removing damaged Collagen and Elastin (allowing space for new healthy fibres) this is also a critical part in wound healing. UV radiation activates large amounts of MMP’s, when this happens these MMPs (Collagenase and Elastase) begin to break down the very fibres they were designed to care for, and will contributes to a breakdown of the dermal matrix and cross linking of collagen, wrinkles and stiffening of the skin.
Now we have covered the basics of how we age, you’re probably feeling a little depressed? Well it’s not all doom and goom! There is much we can do to prevent and treat an ageing skin in a realistic way, I am working on the Prevention and Treatment of Ageing Skin post at the moment, so be patient!