Explainable AI reveals changes in skin microbiome composition linked to phenotypic differences

Alterations in the human microbiome have been observed in a variety of conditions such as asthma, gingivitis, dermatitis and cancer, and much remains to be learned about the links between the microbiome and human health. The fusion of artificial intelligence with rich microbiome datasets can offer an improved understanding of the microbiome’s role in human health. To gain actionable insights it is essential to consider both the predictive power and the transparency of the models by providing explanations for the predictions. We combine the collection of leg skin microbiome samples from two healthy cohorts of women with the application of an explainable artificial intelligence (EAI) approach that provides accurate predictions of phenotypes with explanations. The explanations are expressed in terms of variations in the relative abundance of key microbes that drive the predictions. We predict skin hydration, subject's age, pre/post-menopausal status and smoking status from the leg skin microbiome. The changes in microbial composition linked to skin hydration can accelerate the development of personalized treatments for healthy skin, while those associated with age may offer insights into the skin aging process. The leg microbiome signatures associated with smoking and menopausal status are consistent with previous findings from oral/respiratory tract microbiomes and vaginal/gut microbiomes respectively. This suggests that easily accessible microbiome samples could be used to investigate health-related phenotypes, offering potential for non-invasive diagnosis and condition monitoring. Our EAI approach sets the stage for new work focused on understanding the complex relationships between microbial communities and phenotypes. Our approach can be applied to predict any condition from microbiome samples and has the potential to accelerate the development of microbiome-based personalized therapeutics and non-invasive diagnostics

Ultra-high-performance liquid chromatography–tandem mass spectrometry measurement of climbazole deposition from hair care products onto artificial skin and human scalp

A sensitive and specific ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the measurement of climbazole deposition from hair care products onto artificial skin and human scalp. Deuterated climbazole was used as the internal standard. Atmospheric pressure chemical ionization (APCI) in positive mode was applied for the detection of climbazole. For quantification, multiple reaction monitoring (MRM) transition 293.0 > 69.0 was monitored for climbazole, and MRM transition 296.0 > 225.1 for the deuterated climbazole. The linear range ran from 4 to 2000 ng mL(-1). The limit of detection (LOD) and the limit of quantification (LOQ) were 1 ng mL(-1) and 4 ng mL(-1), respectively, which enabled quantification of climbazole on artificial skin and human scalp at ppb level (corresponding to 16 ng cm(-2)). For the sampling of climbazole from human scalp the buffer scrub method using a surfactant-modified phosphate buffered saline (PBS) solution was selected based on a performance comparison of tape stripping, the buffer scrub method and solvent extraction in in vitro studies. Using this method, climbazole deposition in in vitro and in vivo studies was successfully quantified

Ultra-high-performance liquid chromatography-tandem mass spectrometry measurement of climbazole deposition from hair care products onto artificial skin and human scalp

A sensitive and specific ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the measurement of climbazole deposition from hair care products onto artificial skin and human scalp. Deuterated climbazole was used as the internal standard. Atmospheric pressure chemical ionization (APCI) in positive mode was applied for the detection of climbazole. For quantification, multiple reaction monitoring (MRM) transition 293.0 > 69.0 was monitored for climbazole, and MRM transition 296.0 > 225.1 for the deuterated climbazole. The linear range ran from 4 to 2000 ng mL(-1). The limit of detection (LOD) and the limit of quantification (LOQ) were 1 ng mL(-1) and 4 ng mL(-1), respectively, which enabled quantification of climbazole on artificial skin and human scalp at ppb level (corresponding to 16 ng cm(-2)). For the sampling of climbazole from human scalp the buffer scrub method using a surfactant-modified phosphate buffered saline (PBS) solution was selected based on a performance comparison of tape stripping, the buffer scrub method and solvent extraction in in vitro studies. Using this method, climbazole deposition in in vitro and in vivo studies was successfully quantified

Visualization of zinc pyrithione particles deposited on the scalp from a shampoo by tape-strip sampling and scanning electron microscopy/energy dispersive X-ray spectroscopy measurement

Objective Zinc pyrithione (ZnPT) is widely used as an anti‐fungal active in commercial anti‐dandruff (AD) shampoos. The AD efficacy of ZnPT is highly dependent on the deposition of ZnPT particles onto the scalp during the process of shampoo application and rinse‐off. Since ZnPT materials with different particle sizes and morphologies have different deposition behaviours, the measurement of the actual ZnPT deposition is critical to understand the AD performance delivered by different ZnPT shampoos. The aim of this study is to develop a robust and reliable method for visualizing the particle size and morphology of ZnPT deposited on the scalp from AD shampoos. Methods Hair was washed with a commercially available AD shampoo containing ZnPT and zinc carbonate (ZnCO3). Tape strips were applied to collect the deposited particles from the scalp after AD shampoo application and rinse‐off. The scalp tape strip samples were subjected to scanning electron microscopy/energy dispersive X‐ray spectroscopy (SEM/EDX) measurement. The morphology of the ZnPT particles was visualized by SEM imaging and identification of ZnPT particles was confirmed by EDX analysis. Results For the commercial shampoo studied it was observed that two zinc‐containing particulates with different morphologies and composition remained on the scalp after shampoo application and rinse‐off. As indicated by the EDX spectra, the ZnPT particles deposited onto the scalp surface had polygonal crystal structures. ZnCO3 was also deposited onto the scalp surface. This material was mainly present as aggregated particulates. Conclusion An ex vivo method that combines tape strip sampling and SEM/EDX has been developed for measuring and visualizing the particle size, morphology and composition of ZnPT deposited on the scalp from AD shampoos. This ex vivo measurement method provides higher imaging resolution and more chemical specificity than reflectance confocal microscopy (RCM). To the best of our knowledge, this is the first time that ZnPT particles were distinguishable from other zinc particles on the scalp. Moreover, the new method allows the microstructures of both ZnPT and other zinc particles on the scalp to be imaged

Sensitive and simultaneous quantification of zinc pyrithione and climbazole deposition from anti-dandruff shampoos onto human scalp

A sensitive ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method has been developed and validated for simultaneous quantification of zinc pyrithione (ZPT) and climbazole (CBZ) deposited onto human scalp from anti-dandruff (AD) shampoos. Scrubbing with a buffer solution was used as the sampling method for the extraction of ZPT and CBZ from scalp. Derivatization of ZPT was carried out prior to UHPLC-MS/MS analysis, The identification of ZPT and CBZ was performed by examining ratios of selected multiple reaction monitoring (MRM) transitions in combination with UHPLC retention times. The limit of detection for ZPT and CBZ was established to be 1 and 2 ng/mL, respectively. This sensitivity enables the quantification of ZPT and CBZ at deposition levels in the low ng/cm(2) range. The method was successfully applied for the analysis of scalp buffer scrub samples from an in vivo study. The levels of ZPT and CBZ deposited on the scalp at different time points after application of the AD shampoo were measured. The results revealed that dual-active AD shampoo delivered more ZPT onto the scalp in a single wash than single active shampoo did. The amount of ZPT and CBZ retained on the scalp after AD shampoo application declined over 72 h

The diversity and abundance of fungi and bacteria on the healthy and dandruff affected human scalp.

Dandruff is a skin condition that affects the scalp of up to half the world's population, it is characterised by an itchy, flaky scalp and is associated with colonisation of the skin by Malassezia spp. Management of this condition is typically via antifungal therapies, however the precise role of microbes in the aggravation of the condition are incompletely characterised. Here, a combination of 454 sequencing and qPCR techniques were used to compare the scalp microbiota of dandruff and non-dandruff affected Chinese subjects. Based on 454 sequencing of the scalp microbiome, the two most abundant bacterial genera found on the scalp surface were Cutibacterium (formerly Propionibacterium) and Staphylococcus, while Malassezia was the main fungal inhabitant. Quantitative PCR (qPCR) analysis of four scalp taxa (M. restricta, M. globosa, C. acnes and Staphylococcus spp.) believed to represent the bulk of the overall population was additionally carried out. Metataxonomic and qPCR analyses were performed on healthy and lesional buffer scrub samples to facilitate assessment of whether the scalp condition is associated with differential microbial communities on the sampled skin. Dandruff was associated with greater frequencies of M. restricta and Staphylococcus spp. compared with the healthy population (p<0.05). Analysis also revealed the presence of an unclassified fungal taxon that could represent a novel Malassezia species

Ex-vivo measurement of scalp follicular infundibulum delivery of zinc pyrithione and climbazole from an anti-dandruff shampoo

Efficient delivery of anti-dandruff (AD) actives into the scalp follicular infundibulum as well as onto the scalp surface is critical for the efficacy of AD shampoos. A method involving scalp cyanoacrylate (CA) biopsy sampling, a tailor made cutting device, ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis, scanning electron microscopy (SEM) measurement and Raman imaging has been developed for the measurement of delivery of zinc pyrithione (ZPT) and climbazole (CBZ) from an AD shampoo into the scalp follicular infundibulum. Scalp CA biopsy enables the sampling of ZPT and CBZ delivered into the scalp follicular infundibula as well as onto the scalp surface. Raman imaging of scalp CA biopsy samples allows the visualization of the spatial distribution of ZPT and CBZ deposited on the scalp. A tailor made cutting device enables the separation of the scalp follicular infundibulum sample (20 pm below the scalp surface) from the scalp surface samples (including top 20 pm of infundibula). UHPLC-MS/MS was used as a sensitive and specific methodology enabling the quantification of ZPT and CBZ without interference. Using this method, both ZPT and CBZ were successfully quantified and spatially visualized within the scalp follicular infundibulum, after scalp was washed with an AD shampoo. (C) 2017 Elsevier B.V. All rights reserved