Dry, thin and sagging skin is among the most common complaints of women over the age of 50. This is due to reduced protective, preventative and regenerative aspects of aged skin. Aged skin is manifested by reduced stratum corneum (SC) moisturization, and although transepidermal water loss (TEWL) is known to be normal or improved with age, the epidermal barrier repair capacity after removing the superficial layers of the barrier by tape stripping is significantly impaired.
Electron microscopy studies have shown a decreased size and number of keratohyalin granules (KHGs), the repository of profilaggrin in the keratinocytes, in aged skin. In this respect, reduced SC natural moisturizing factors (NMF) have been observed due to reduced amounts of profilaggrin-rich KHGs.2 Equally, abnormal intercellular lipid lamellae occur in aged skin, accompanied by a reduction in the levels of SC ceramides and especially ceramide EOS-linoleate. This is a result of the reduced lipid synthetic capacity of the epidermis that occurs during aging.
Further epidermal changes that occur with aging include the premature expression of involucrin4 and the decline in transglutaminase-1 and filaggrin levels. These changes can impact SC formation and maturation.
