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Resolving Water, Proteins, and Lipids from In Vivo Confocal Raman Spectra of Stratum Corneum through a Chemometric Approach

Development of this in vivo confocal Raman spectroscopic method enables the direct measurement of water, proteins, and lipids with depth resolution in ...

Mason Business Center

Confocal Raman has been widely used for measuring the water concentration profile inside skin to calculate clinical end points, such as stratum corneum thickness. In this article, multivariate curve resolution was applied to resolve the pure components contained in high frequency (2500-4000 cm) in vivo confocal Raman data. Three components were identified by comparing with reference spectra of materials in skin. These three components are water, protein, and lipid. The score values associated with these three components were transformed to mass ratio by leveraging the response factors for protein and lipid in a calibration model utilizing the pure material spectra. The concentration profiles for protein and lipid as a function of depth across the stratum corneum are utilized as new clinical end points. Results from an in vivo study with individuals who experience atopic dermatitis symptoms successfully demonstrated a statistical difference between Raman spectra from nonlesion and lesion skin sites. Trends in the depth profiles of the skin components are consistent with previous literature reports.

MCR Approach Revealing Protein, Water, and Lipid Depth Profile in Atopic Dermatitis Patients' Stratum Corneum via in Vivo Confocal Raman Spectroscopy.

A quantitative and objective indicator for skin health via the microbiome is of great interest for personalized skin care, but differences among skin sites and across human populations can make this goal challenging. A three-city (two Chinese and one American) comparison of skin microbiota from atopic dermatitis (AD) and healthy pediatric cohorts revealed that, although city has the greatest effect size (the skin microbiome can predict the originated city with near 100% accuracy), a microbial index of skin health (MiSH) based on 25 bacterial genera can diagnose AD with 83 to ∼95% accuracy within each city and 86.4% accuracy across cities (area under the concentration-time curve [AUC], 0.90). Moreover, nonlesional skin sites across the bodies of AD-active children (which include shank, arm, popliteal fossa, elbow, antecubital fossa, knee, neck, and axilla) harbor a distinct but lesional state-like microbiome that features relative enrichment of  over healthy individuals, confirming the extension of microbiome dysbiosis across body surface in AD patients. Intriguingly, pretreatment MiSH classifies children with identical AD clinical symptoms into two host types with distinct microbial diversity and treatment effects of corticosteroid therapy. These findings suggest that MiSH has the potential to diagnose AD, assess risk-prone state of skin, and predict treatment response in children across human populations. MiSH, which is based on the skin microbiome, can quantitatively assess pediatric skin health across cohorts from distinct countries over large geographic distances. Moreover, the index can identify a risk-prone skin state and compare treatment effect in children, suggesting applications in diagnosis and patient stratification.

A Microbiome-Based Index for Assessing Skin Health and Treatment Effects for Atopic Dermatitis in Children.

It acknowledged that skin care is an important part of atopic dermatitis therapy. However, clinical evidences are limited for the best bathing practices, especially the skin health performance of cleansing products on children's atopic dermatitis skin.

Karl Wei

Procter and Gamble

Mason Business Center

Resolving Water, Proteins, and Lipids from In Vivo Confocal Raman Spectra of Stratum Corneum through a Chemometric Approach