Aging and Intrinsic Aging: Pathogenesis and Manifestations

Biotribology of the ageing skin—Why we should care

“…A major physiological change associated with ageing is a reduction in cell proliferative capacity which leads to cellular senescence and alters the biosynthetic activity of skin derived cells. It is widely accepted that DN damage and chromosomes' telomere shortening [11,[53][54][55] are the two main triggers of ageing. Genetics determines the rate of skin ageing by controlling essential factors such as immunochemistry, cell biochemistry and hormonal mechanisms.…”

“…From a tribological perspective, detrimental alterations of skin biophysical properties with age [11][12][13] have fundamental consequences on how one interacts with the body's inner and outer environments [14][15][16]. This stems from the fact that, besides being the largest organ of the human body, and also nearly covering its entirety, the skin is a multifunctional interface which mediates these interactions.…”

It is time to classify biological aging as a disease

“…Additionally, normal in a medical context is generally defined as no deviation outside of the normal reference range for that age and sex, whilst diseases are seen as deviation from this normal condition for that age and sex (Boorse, 1975; Assaf et al, 2010). Thus, someone with a blood pressure of below 120/80 is seen as normal while a blood pressure above 140/90 or below 85/55 is abnormal and a sign of disease (WHO, 2015).…”

Constitutive Modelling of Skin Ageing

“…These alterations involve decreased proliferative capacity which leads to cellular senescence and altered biosynthetic activity of skin derived cells. Intrinsic ageing is triggered by two main mechanisms which can operate in concert, namely DNA damage and chromosomes' telomere shortening [4][5][6][7]. The fact that the skin of people of identical ages living in similar environments may appear younger-or older-looking is a testimony of the fundamental role of genetics in skin ageing.…”

“…1). These alterations have important consequences for skin physiology [4,16], rheology [17], surface physics and tribology [18][19][20]. Aged skin is more prone to developing disorders such as xerosis and pruritus [21], skin cancers [22] as well as debilitating, costly and lifethreatening skin tears and pressure ulcers [23].…”