Aging is the progressive decline in biological functions of the organism, linked to alterations in cellular, subcellular and molecular structures. Aging in itself begins after reaching reproductive maturity and at the end of the development process, when the body reaches the maximum level of its biological potential. As far as endocrinology is concerned, aging is responsible for the gradual and linear decrease in the physiological reserve of each hormonal system.
There are two main causes of the changes of the skin that occur over time:
chronological aging, which is a physiological process which we cannot avoid over the decades, mainly determined by genetic factors, influenced by environmental factors such as oxidative attacks triggered by the action of exogenous factors including environmental pollutants and metals heavy, and photo-aging, which overlaps the above in exposed areas. It is a degenerative process resulting from chronic exposure to UV rays. However, a careful assessment is required due to the morphological similarities that the two processes have.
Chronoaging: from a clinical point of view, the skin appears thinner, lighter and less elastic. It does, in fact, damage the mechanical properties of the skin, of which the dermis constitutes the support element, due to the decreasing capacity of the fibroblasts to synthesise the extracellular matrix components, until it reaches atrophy of the tissues.
Photoaging: chronic exposure to sunlight is responsible for dermatological alterations that may occur in the areas most exposed to sunlight: dryness, peeling, rough and thickened skin, accentuation of expression lines. Chronic sun damage causes major alterations in skin pigmentation. This often leads to the appearance of freckles, pigmented keratosis, yellowing of skin. Dermatoeliosis causes the formation of telangiectasias, i.e. the degeneration of the elastic fibres and the modified distribution of collagen. In photoaging free radicals, which are excessive in number compared to the neutralising capacity of antioxidant systems, damage the DNA, lipids and proteins and interfere with the transduction mechanisms involved in the differentiation and growth, creating an imbalance which leads to the photo-carcinogenesis of the epidermis.
The causes of aging have not been completely clarified; both modifications that occur in the immune system and the endocrine system certainly play a major role.
The immune system is the organ responsible for defending our body against pathogenic foreign substances by means of the production of specialised cells (T, B lymphocytes) and particular interleukins.
Interleukins: proteins secreted by white blood cells with a variety of functions, from the stimulus to cellular differentiation and induction of the inflammatory process. During the aging process, there is an imbalance in the production of such proteins by the body, with an increase in the vulnerability of the same to extraneous agents. Typically, there is an increase in the production of IL-6, responsible for an increase of the inflammatory process; excessive amounts of IL-6 seems to favour the deposition of amyloid proteins as well as bone reabsorption and hence stimulating respectively the onset of Alzheimer’s Disease, osteopenia and osteoporosis.
The endocrine or hormonal system is represented by a group of glands and cells (called endocrine glands and endocrine cells) which secrete protein or lipid substances called hormones. The endocrine system controls the functions of the organism. As aging progresses, we see a decrease in the levels of sex hormones, their precursors such as DHEA and pregnenolone, melatonin, thyroid hormones and growth hormones. On the other hand, the values â€‹â€‹of other hormones such as cortisol and prolactin, tend to rise with age.
Oestrogens: Sex hormones produced by the ovaries during the menstrual cycle (estradiol and estrone), whose biosynthesis and regulation depends on the pituitary gonadotropins (FSH and LH). They have different actions on different tissues: they stimulate the development of the stromal effect on the mammary ducts, they are responsible for the accelerated growth phase and the closing of the accretion epiphyses during puberty; they modify the localisation of body fat; they reduce the rate of bone reabsorption antagonising the action of PTH on bones and are also responsible for the standard maintenance of normal skin structures and blood vessels.
Menopause: this is the most evident aging process due to the drastic decrease in sex hormones in women (oestrogens) which occurs at around 50 years of age. The male version concerns testosterone, but in this case the reduction does not always occur in all men or in the proportions with which oestrogen decreases. It has emerged from certain research studies, however, that certain risk factors for coronary heart disease are present at a greater level when there is hormone deficiency; on the contrary, high levels of testosterone are associated with protective factors such as higher levels of HDL cholesterol. In practice, the lack of testosterone could favour atherosclerosis of the coronary arteries.
During menopause women undergo a series of changes in their body essentially related to oestrogen deficiency. During the first five years of menopause, there is an abrupt decline of both the collagenous component of the skin, with a consequent decrease of suppleness and elasticity of the skin, but there is also a considerable loss of bone mass, which increases the risk of fractures quite considerably and continues much more gradually as years go by. The fact that all this can happen, regardless of age, even in young women who face early menopause, highlights the huge importance of the hormonal sphere in the aging process.