Lipid loses and barrier function modifications of the brown‐to‐white hair transition

Abstract

Background The main objective of this study was to determine the lipid profile of brown and white Caucasian hair fibres and the effects of lipids on the properties of fibres. Materials and Methods To determine the structures of white and brown hair lipid bilayers, cross sections of fibres of both hair types were examined using synchrotron‐based μ‐FTIR mapping. Dynamic vapour sorption (DVS) analyses were also performed to determine the differences in the barrier function of both fibres. Results Spatial identification of lipids showed that a great amount of lipids was present in the medulla of fibres of both hair types, but important differences were also observed between cuticles of the different fibres. The cuticle of a white hair fibre showed a significant decrease in its lipid content, but did not show differences in the lateral packing order with respect to the cuticle of a brown hair fibre. The cortex and medulla of the white hair fibre also exhibited a significant decrease in its lipid content but with a higher lateral packing order than brown hair. Using DVS analysis, it was found that the water dynamics of white hair fibres differed from those of brown hair fibres, showing a decrease in their total capacity to absorb water and an increase in the velocity of the exchange of water with the environment. Conclusion The results of both techniques demonstrated a high correlation between the characteristics of the lipids located in the cuticle and the water dynamics of the fibres.

Investigation of the molecular signature of greying hair shafts

“…However, statistical analyses showed that markers of lipid and protein behaviours were significantly modulated during hair greying. Indeed, investigating the spectral vibration related to trans / gauche ratio (1130/1080 cm −1 ) [7] (Figure 4c) highlighted changes in lipid conformation with a significant and progressive decrease of this ratio during hair greying (Figure 4d). These results demonstrate an alteration of the barrier function with greying.…”

“…Using infrared spectroscopy (μ‐FTIR analysis), Oliver and collaborators recently investigated the lipid profile in the brown to white hair transition but they did not focus on intermediate greying hair [7]. By investigating CH 2 asymmetric stretching at 2850 cm −1 , they reported a reduction of the lipid content within white hairs.…”

“…A high quantity of gauche conformers, on the other hand, weakens the compactness of the hair lipid structures [34]. Previous studies [7, 35] reported that changes in lipids’ amount and arrangement in the cuticle region may modify the water dynamics of the fibre. Hence, water dynamics of white hair fibres differed from those of brown hair fibres, showing a decrease in their total water absorbance capacity and an increase in the water exchange velocity with the environment.…”

“…This particular arrangement forms a protective barrier, reinforced by a network of lipids, representing only 1 to 9% of the hair mass, but playing a key role in maintaining hydrophobicity at the surface of the hair and resulting in its protection [6]. Indeed, predominance of lipids in trans conformation results in a good structural organization conferring a shield from environmental stresses and preventing penetration of foreign substances [7]. The second layer and main core of the hair is the cortex.…”

Exploration of potential lipid biomarkers for premature canities by UPLC‐QTOF‐MS analyses of hair follicle roots

“…[5] The un-pigmented fibres were shown to have decreased amounts of lipids in all of the hair layers; this decrease is more critical within the cuticle. [6] Hair follicle is a unique micro structure, and it has the function of barrier and regulation. Therefore, we focused on the lipid of hair follicles to explore the pathogenesis of premature canities on the molecular level.…”