Age and Sex Variation in Lipid Composition of Human Fingernail Plates¹

Abstract

In contrast to epidermal lipid metabolism, the lipid biochemistry of nails has yet been poorly investigated. Our purpose was to define a reference population of healthy individuals as a base for the better understanding of nail diseases and age-induced changes. Therefore, we developed a method of processing and extracting the nail plates enabling us to assess the most relevant epidermal lipid classes by HPTLC. Our study revealed that nail plate lipid composition varies with age and sex: the lipid composition of the fertile years shows distinct profiles compared to that of childhood and old age, suggesting an influence of sex hormones on nail lipogenesis. Our results open the possibility in the future of an easier comparison between healthy and diseased nails and enable us to investigate factors influencing nail lipid composition such as drugs, metabolic diseases, toxic agents, cosmetics and nail therapeutics.

Introduction to skin aging

“…88 Nails become more brittle in the elderly and develop beaded ridging due to a reduction in lipophilic sterols and free fatty acids. 89 …”

An Assessment of the Human Nail Plate pH

“…Hence, the pH value measured on the nail plate surface is an apparent pH and should be interpreted with caution, as has been advised for skin pH measurements [26,35] . As mentioned in the Introduction, the nail plate constituents include proteins, mucopolysaccharides, water and lipids [2,[12][13][14] . It is feasible that some of the water-soluble nail plate components are extractable and contribute to a reading of the nail plate surface pH when the latter is measured with a hydrated glass electrode.…”

A homozygous missense mutation in SLC25A16 associated with autosomal recessive isolated fingernail dysplasia in a Pakistani family

“…Lipids are an essential part of nails in addition to keratins, water and minerals. Among the key lipids in nails are ceramides, sterols, triglycerides and squalene, and free fatty acids . In nails lipids exist both in the intracellular and extracellular parts.…”