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Background: Age‐induced hair graying (AIHG)is one of the visual hallmarks of aging, but its biological mechanism remains unclear. Changes in the hair‐follicle lipid profiles associated with AIHG have not been defined. Objectives: To define the differences in the hair follicle lipid profiles of female black and gray/white hair follicles. Methods: The lipid profile of hair follicles was determined by ultra‐performance liquid chromatography‐quadrupole time‐of‐flight mass spectrometry (UPLC‐QTOF‐MS). Multivariate data analysis was used to determine changes in the lipid profiles in hair follicle roots. Results: We identified the different lipids in hair follicle roots between black hair (HB) and white hair (HW) and analyzed the key lipids that contribute to the development of HW. The results showed that the total lipid content of the HW was significantly reduced. There were significant differences in sphingolipid content, with HB higher than HW. Two subclasses, glucosylceramide (GlcCer) and galactosylceramide, were significantly different. GlcCer, phosphatidylserine, and phosphatidic acid levels were higher in the HB group. The sphingolipid metabolism involved in GlcCer(d18:1/24:1[15Z]) is a statistically significant lipid metabolic pathway. Conclusion: Five major individual lipid candidates are involved in the production of AIHG. GlcCer shows a significant reduction in HW and is a potential target for further research into AIHG. [ABSTRACT FROM AUTHOR]

Background and Aims: Self‐perception of sensitive skin (SPSS) has several consequences, including skin barrier damage, which is prevented by barrier sebum. We analyzed lipidome profiles of skin surface lipids (SSLs) in patients with SPSS and healthy controls and explored the mechanism of action of potential lipid markers on the repair of damaged barrier cells to better understand SSL abnormity in these patients. Methods: Ultraperformance liquid chromatography–quadrupole time‐of‐flight mass spectrometry was used to investigate SSL variations in major lipid classes, subclasses, and species. Reverse‐transcription polymerase chain reaction (RT‐PCR) was used to examine changes in intracellular gene expression following cell barrier damage repair by potential lipid markers. Results: There were significant differences in the lipidomes of individuals between groups. Individuals with SPSS showed significantly increased levels of two diacylglycerols and one very‐short‐chain free fatty acid and significantly decreased levels of three ceramides (Cers), four glycerophospholipids, and one very‐long‐chain free fatty acid. RT‐PCR revealed that after damage repair by Cer/Glucosylceramide (GlcCer), the expression of two genes in the sterol regulatory element‐binding protein and three in the peroxisome proliferator‐activated receptor pathway significantly increased. Causes of skin barrier damage in patients with SPSS are related to the amount and type of lipids. Conclusion: Cer/GlcCer can promote lipid synthesis and secretion by upregulating lipid‐related gene expression to repair barrier damage. [ABSTRACT FROM AUTHOR]

Background: Diabetes has become popular and has become one of the most important global health care challenges. Patients with diabetes have a high incidence of skin diseases. Cell and animal models are often used to study the skin conditions of people with diabetes. Methods: In this study, a volunteer questionnaire survey, skin lipomics analysis based on ultra-high performance liquid chromatography-quadrupole tandem time-of-flight mass spectrometry (UPLC-QTOF-MS), and weighted gene co-expression network analysis (WGCNA) were used to study the differences in skin conditions and skin lipids of participants with type 2 diabetes mellitus (Group D) versus healthy individuals (Group H) and the correlation between these groups. The questionnaire was used to investigate personal basic, diabetes, and facial skin status information of 77 female volunteers aged 55– 65 years old from the Peking University Shougang Hospital. The facial skin lipids of all volunteers were analysed by UPLC-QTOF-MS technique; the differential lipids between groups D and H were analysed by partial least-squared discriminant and univariate analysis. Results: In total, 23 kinds of differential lipids were identified, all of which belonged to sphingolipids. The use of WGCNA combined clinical information with lipid analysis to study the relationship between glycosylated haemoglobin, skin pigmentation/non-pigmentation, and skin lipids. Two types of lipids were identified to distinguish between hub lipids of high and low glycosylated haemoglobin; 12 types of lipids were identified that could distinguish between the hub lipids of pigmented and non-pigmented participants (PLS-DA). Conclusion: The experimental results not only provide a reference for the diagnosis and classification of diabetes via analysing the skin lipids of patients, but also provides a theoretical basis for further study on the effects of diabetes on the skin of patients. [ABSTRACT FROM AUTHOR]

We have recently shown that both UVB and BaP can induce the production of ROS, apoptosis and even cancer. However, the differences in the metabolic profiles of skin damaged by UVB, BaP or UVB combined with BaP have not been studied. Therefore, we examined the metabolic changes in the human foreskin fibroblast injured by UVB or BaP or the combination of the two, using ultra performance liquid chromatography (UPLC) coupled with quadrupole time-of-flight mass spectrometry (qTOF-MS). 24 metabolites were altered in the UVB damage group, 25 in the BaP damage group, and 33 in the UVB combined with BaP group. These alterations indicated that the metabolic mechanisms of HFF-1 cells treated with UVB or BaP are related to multiple main metabolites including glycerophosphocholine (PC), lactosylceramide (LacCer), guanidinosuccinic acid (GSA), glutathione(GSH), and lysophosphatidylcholine (LysoPC) and the main mechanisms involved glycerophospholipid and glutathione metabolism. Thus, our report provided useful insight into the underlying mechanisms of UVB and BaP damage to skin cells. [ABSTRACT FROM AUTHOR]

Background: The rate of premature greying, referred to as canities, varies among populations, and effective treatments are lacking. However, few studies at the molecular level have been reported. Objectives: Comparing lipid profiles of individuals with premature canities and healthy volunteers to explore the mechanism of premature canities. Methods: Ultra‐performance liquid chromatography/quadrupole time‐of‐flight mass spectrometry (UPLC‐QTOF‐MS) was used to detect lipids in the hair follicle root. Multivariate data analysis was used to show lipid changes in follicle roots. Results: We identified lipids in the hair follicle root that differ between black and white hair and analysed key lipids contributing to white hair development. We divided the samples into three groups: PC‐WH (Premature canities‐White hair), PC‐PH (Premature canities‐Pigmented hair), Control‐PH (Pigmented hair). Phosphatidylethanolamine (PE), phosphatidylcholine (PC), vitamin D3 (VD3) and cholesterol in Control‐PH were higher than those in PC‐WH. Sphingomyelin (SP), phosphatidic acid (PA), VD3 and diglyceride (DG) were lower in PC‐WH than in PC‐PH. Levels of VD3 were highest in Control‐PH, gradually decreased as the severity of PC‐PH increased and were lowest in PC‐WH. Conclusion: There are 7 main class candidate compounds involved in the generation of white hair. VD3 showed a substantial decrease in white hair and was a potential target for further studies of premature canities. [ABSTRACT FROM AUTHOR]

Background: Sensitive skin refers to skin that tends to be highly responsive to stimuli such as physical, chemical, and psychological. Psychological factors play an important role in the pathology of sensitive skin. Objective: This study investigated lipid difference between sensitive skin caused by psychological stress and normal skin, followed by construction of a support vector machine (SVM). Methods: A noninvasive method was used to collect lipid samples from the skin surface. Ultra‐performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC‐Q‐TOF‐MS) technique and partial least squares‐discriminant analysis (PLS‐DA) was used to screen for differential lipids. A correlation analysis was performed on differential lipids, and a support vector model was established based on the differential lipids. Results: Twelve differential lipids were obtained, and the most differentiating species were triacylglycerols (TGs), followed by monounsaturated fatty acids (MUFAs), saturated fatty acids (SFAs), diacylglycerols (DGs), and 6‐hydroxysphingosine levels. Triglyceride, SFA, and MUFA species showed a high correlation, and the support vector machine (SVM) differentiation model based on differential lipids had a 100% accuracy rate. Conclusion: Psychological stress may cause damage to the permeability and antimicrobial barriers of the skin, thereby resulting in sensitive skin. Differentiation models based on SVMs have good prospects for distinguishing sensitive skin caused by psychological stress. [ABSTRACT FROM AUTHOR]