The role of ceramides in skin homeostasis and inflammatory skin diseases

Enhancing cellular affinity for skin disorders: Electrospun polyurethane/collagen nanofiber mats coated with phytoceramides

Although the use of thermoplastic polyurethane (Tpu) nanofiber mats as wound dressings is of great interest due to their mechanical properties, they are hindered by their poor wettability and bioavailability. In this study, we aimed to improve the cellular affinity of Tpu nanofiber mats for skin disorders by incorporating extracted collagen (Col) from tendons and physically mixed with a layer of phytoceramides (Phyto) to produce TpuCol@X-Phyto mats in which the weight % of Phyto relatively to the weight of the solution was X = 0.5, 1.0, or 1.5 wt% via facile electrospinning approach. The collective observations strongly indicate the successful incorporation and retention of Phyto within the TpuCol architecture. An increase in the Phyto concentration decreased the water contact angle from 69.4° ± 3.47° to 57.9° ± 2.89°, demonstrating improvement in the hydrophilicity of Tpu and binary blend TpuCol nanofiber mats. The mechanical property of 1.0 wt% Phyto aligns with practical requirements owing to the presence of two hydroxyl groups and the amide linkage likely contributing to various hydrogen bonds, providing mechanical strength to the channel structure and a degree of rigidity essential for transmitting mechanical stress. The proliferation of human skin fibroblast (HSF) peaked significantly 100 % with TpuCol@X-Phyto mats coated for X =1.0 and 1.5 wt% of Phyto. Electrospun scaffolds with the highest Phyto content have shown the lowest degree of hemolysis, demonstrating the high level of compatibility between them and blood. The TpuCol@1.5Phyto mat also demonstrated higher efficacy in antibacterial and antioxidant activities, achieving a rate of DPPH radical scavenging of 83.3 % for this latter property. The most notable wound closure among all tested formulations was attributed to higher Phyto. Thus, the developed TpuCol@1.5Phyto nanofiber formula exhibited enhanced healing in an in vitro epidermal model.

Untargeted Lipidomics Analysis to Discover Lipid Profiles and Biomarkers of Rabbit Acne Model and Reveal Action Mechanism of Isotretinoin

Background

Acne vulgaris (AV), a chronic inflammatory pilosebaceous disorder, affects 80-90% of teenagers. This study aimed to discover lipid profiles and biomarkers of the rabbit ear acne model, and investigate the mechanism of isotretinoin in treating acne at the lipid level.

Methods

Untargeted lipidomic analysis using ultra-high performance liquid chromatography system (UHPLC) coupled to q-extraction plus was performed to identify skin lipid metabolites in blank control (groups C), model group (group M) and isotretinoin group (group T). Multivariate statistical analysis was used to process the lipidomics data.

Results

A total of 43 lipid classes comprising 6989 lipid species were identified from the mass spectrometry data. The orthogonal partial least squares discriminant analysis (OPLS-DA) model demonstrated significant separation in skin lipidomic profiles between group M and group C. With variable influence on projection (VIP) > 1.0 and P-value < 0.05, 299 significantly different lipid metabolites were identified. These lipid metabolites consisted mainly of ceramides (Cer) (53.85%), phosphatidylethanolamines (PE) (9.03%), phosphatidylcholines (PC)(5.35%), and sphingomyelin (SM)(4.01%). Combining with AUC ≥ 0.9 as the elected criteria, Cer (d18;1_24:0), zymosterol (ZyE)(33:5), Cer (t43:1), ZyE (33:6), ZyE (24:7), and ZyE (35:6) have "high" accuracy. Isotretinoin treatment normalized 25 lipid metabolites in the acne model.

Conclusion

Our findings provide new insights into the role of lipid metabolism in the pathogenesis of acne and the action mechanism of isotretinoin.

Update on the pathogenesis of atopic dermatitis

Atopic dermatitis is a chronic, recurrent, and multifactorial skin-mucosal manifestation resulting from the interaction between elements mainly associated with the skin barrier deficit, the homeostasis of the immune response, neurological aspects, and patterns of reactivity to environmental antigens, which are established in genetically predisposed individuals. In addition to the skin, atopic diathesis involves other organs such as the airways (upper and lower), eyes, digestive tract, and neuropsychiatric aspects, which inflict additional morbidity on the dermatological patient. The different phenotypes of the disease fundamentally depend on the participation of each of these factors, in different life circumstances, such as age groups, occupational exposure patterns, physical activity, pollution, genetic load, and climatic factors. A better understanding of the complexity of its pathogenesis allows not only the understanding of therapeutic targets but also how to identify preponderant elements that mediate disease activity in each circumstance, for selecting the best treatment strategies and mitigation of triggering factors. This narrative review presents an update on the pathogenesis of atopic dermatitis, especially aimed at understanding the clinical manifestations, the main disease phenotypes and the context of available therapeutic strategies.

Multi-omics analysis to evaluate the effects of solar exposure and a broad-spectrum SPF50+ sunscreen on markers of skin barrier function in a skin ecosystem model

Sun exposure induces major skin alterations, but its effects on skin metabolites and lipids remain largely unknown. Using an original reconstructed human epidermis (RHE) model colonized with human microbiota and supplemented with human sebum, we previously showed that a single dose of simulated solar radiation (SSR) significantly impacted the skin metabolome and microbiota. In this article, we further analyzed SSR-induced changes on skin metabolites and lipids in the same RHE model. Among the significantly altered metabolites (log2-fold changes with p ≤ 0.05), we found several natural moisturizing factors (NMFs): amino acids, lactate, glycerol, urocanic acid, pyrrolidone carboxylic acid and derivatives. Analyses of the stratum corneum lipids also showed that SSR induced lower levels of free fatty acids and higher levels of ceramides, cholesterols and its derivatives. An imbalance in NMFs and ceramides combined to an increase of proinflammatory lipids may participate in skin permeability barrier impairment, dehydration and inflammatory reaction to the sun. Our skin model also allowed the evaluation of an innovative ultraviolet/blue light (UV/BL) broad-spectrum sunscreen with a high sun protection factor (SPF50+). We found that using this sunscreen prior to SSR exposure could in part prevent SSR-induced alterations in NMFs and lipids in the skin ecosystem RHE model.

An Investigation into the Transdermal Behavior of Active Ingredients by Combination of Experiments and Multiscale Simulations

Transdermal behavior is a critical aspect of studying delivery systems and evaluating the efficacy of cosmetics. However, existing methods face challenges such as lengthy experiments, high cost, and limited model accuracy. Therefore, developing accurate transdermal models is essential for formulation development and effectiveness assessment. In this study, we developed a multiscale model to describe the transdermal behavior of active ingredients in the stratum corneum. Molecular dynamics simulations were used to construct lipid bilayers and determine the diffusion coefficients of active ingredients in different regions of these bilayers. These diffusion coefficients were integrated into a multilayer lipid pathway model using finite element simulations. The simulation results were in close agreement with our experimental results for three active ingredients (mandelic acid (MAN), nicotinamide (NIC), and pyruvic acid (PYR)), demonstrating the effectiveness of our multiscale model. This research provides valuable insights for advancing transdermal delivery methods.

A Recalcitrant Skin Lesion and Subsequent Infection in a Recreational Intramural Male Athlete: A Case Report

A 35-year-old intramural male athlete presented to the athletic training staff with a 4.5- × 2.2-cm itchy, painful, swollen, and infected insidious skin lesion on his right lateral malleolus due to an underlying dermatologic deficiency. Suspecting infection, the patient was referred to his nurse practitioner and was diagnosed with atopic dermatitis caused by a ceramide deficiency. He was placed on cefalexin and mupirocin 2% ointment but returned due to the lesion increasing to 8.5 × 6 cm, although the infection seemed controlled. He was instructed to use Ceravé topical cream, clobetasol propionate 5%, and to consume foods rich in healthy oils (omega-3 fatty acids, olive oil). Unmitigated, this lesion could have resulted in severe infection and tissue damage. Atopic dermatitis is relatively common in the general population, but its appearance in healthy athletes highlights that athletic trainers need to be well versed in not just apparent causes of skin ailments (ie, infection) but also root causes.

Efficacy and Safety of Oral Administration of Wine Lees Extract (WLE)-Derived Ceramides and Glucosylceramides in Enhancing Skin Barrier Function: A Randomized, Double-Blind, Placebo-Controlled Study

BACKGROUND

Our search for plant-derived ceramides from sustainable sources led to the discovery of ceramides and glucosylceramides in wine lees.

OBJECTIVE

This study evaluated the efficacy and safety of wine lees extract (WLE)-derived ceramides and glucosylceramides in enhancing skin barrier function.

METHODS

A randomized, double-blind, placebo-controlled study was conducted with 30 healthy Japanese subjects aged 20-64. Subjects were allocated to receive either the WLE-derived ceramides and glucosylceramides (test group) or placebo for 12 weeks. The primary outcome was transepidermal water loss (TEWL), and secondary outcomes included skin hydration, visual analog scale (VAS) of itching sensation, and the Japanese Skindex-29.

RESULTS

One participant withdrew for personal reasons, resulting in 29 subjects for data analysis (placebo n = 15; test n = 14). The test group showed a tendency of lower TEWL compared to the placebo after 8 weeks (p = 0.07). Furthermore, after 12 weeks of administration, the test group had significantly lower TEWL than the placebo (p = 0.04). On the other hand, no significant differences were observed in the secondary outcome parameters. No adverse events related to the supplements were reported.

CONCLUSIONS

Oral supplementation of WLE-derived ceramides and glucosylceramides is a prominent and safe approach to enhancing skin barrier function and health.

TRIAL REGISTRATION

(UMIN000050422).

Piperlongumine regulates genes involved in the skin barrier in epidermal keratinocyte HaCaT cells

Given that the skin is the largest tissue in the human body, performing external barrier functions with innate and adaptive immunity and undergoing substantial changes during aging, it is under investigation as a major target of various bioactive molecules. In the present study, we examined the biological activity of the senolytic piperlongumine by analyzing alterations in mRNA expression of notable skin genes using transformed aneuploid immortal epidermal keratinocytes, HaCaT cells. We observed that piperlongumine increased the mRNA expression of genes playing critical roles in skin barrier function. In addition, piperlongumine increased expression enzymes involved in the synthesis of ceramide, a major component of intercellular lipids. Furthermore, we measured the protein levels of various cytokines secreted by epidermal keratinocytes and found changes in the release of GRO-αβγ, CCL5, and MCP1. Additionally, we observed that piperlongumine treatment modulated the expression of keratinocyte-specific aging markers and influenced telomerase activity. Based on these findings, piperlongumine could regulate the physiological activity of epidermal keratinocytes to induce beneficial effects in human skin by regulating important skin-related genes.

Nuclear receptors for epidermal lipid barrier: Advances in mechanisms and applications

The skin plays an essential role in preventing the entry of external environmental threats and the loss of internal substances, depending on the epidermal permeability barrier. Nuclear receptors (NRs), present in various tissues and organs including full-thickness skin, have been demonstrated to exert significant effects on the epidermal lipid barrier. Formation of the lipid lamellar membrane and the normal proliferation and differentiation of keratinocytes (KCs) are crucial for the development of the epidermal permeability barrier and is regulated by specific NRs such as PPAR, LXR, VDR, RAR/RXR, AHR, PXR and FXR. These receptors play a key role in regulating KC differentiation and the entire process of epidermal lipid synthesis, processing and secretion. Lipids derived from sebaceous glands are influenced by NRs as well and participate in regulation of the epidermal lipid barrier. Furthermore, intricate interplay exists between these receptors. Disturbance of barrier function leads to a range of diseases, including psoriasis, atopic dermatitis and acne. Targeting these NRs with agonists or antagonists modulate pathways involved in lipid synthesis and cell differentiation, suggesting potential therapeutic approaches for dermatosis associated with barrier damage. This review focuses on the regulatory role of NRs in the maintenance and processing of the epidermal lipid barrier through their effects on skin lipid synthesis and KC differentiation, providing novel insights for drug targets to facilitate precision medicine strategies.

Efficacy of ceramides and niacinamide-containing moisturizer versus hydrophilic cream in combination with topical anti-acne treatment in mild to moderate acne vulgaris: A split face, double-blinded, randomized controlled trial

INTRODUCTION

Topical therapy is the mainstay treatment of acne, and topical retinoids such as tretinoin, tazarotene, and adapalene are recommended as the first-line therapy for mild to moderate acne. However, the cutaneous irritations may occur, and the dermocosmetics are recommended to prevent side effects of anti-acne drugs and adhere to treatment. Thus, this study aims to compare the efficacy and tolerability of ceramides and niacinamide-containing moisturizer (CCM) versus hydrophilic cream in combination with topical anti-acne treatment in mild to moderate acne vulgaris.

METHODS

This was an 8-week, randomized, double-blinded, split face study in 40 patients assigned for topical anti-acne medications (5% benzoyl peroxide and 0.1% adapalene gel), then randomly applied CCM or hydrophilic cream. All patients were followed at week 0, 2, 4, and 8 for acne improvement, adverse reactions, biometric, and biophysical evaluation.

RESULTS

CCM could significantly improve the non-inflammatory, inflammatory, and total acne lesions compared with hydrophilic cream after week 8 of treatment. Interestingly, there was an improvement of global worst score, hemoglobin index, melanin index, TEWL, skin hydration, sebum production, and skin surface pH, with no statistically significant differences between the two treatments. No serious side effects from clinical application of CCM and hydrophilic cream in mild to moderate acne vulgaris patients.

CONCLUSION

Ceramide and niacinamide-containing moisturizer in combination with anti-acne medication can significantly improve acne lesions and decrease cutaneous irritations toward a satisfactory treatment outcome of mild to moderate acne vulgaris.

Lipidomics-based analysis of lipid differences between dry skin of women aged 22-28 years and 29-35 years

BACKGROUND

The skin condition of women is different at different ages, and skin surface lipids are also different. According to the "7-7 theory" of the Huangdi Neijing, the physiological condition of women changes significantly every 7 years, and women aged 22-28 are in the "4-7" stage as mentioned in the "7-7 theory" of the Huangdi Neijing. Women's skin is in different states at different ages and produces different lipids.

OBJECTIVES

To explore the key lipids that contribute to skin differences between women aged 22-28 and 29-35 years, and to explore the relationship with physiological parameters and daily routine.

METHODS

Differential lipids were detected and screened between 22-28 year old (group D1) and 29-35 year old (group D2) dry-skinned women using UPLC-Q-TOF-MS and correlated between the two groups with questionnaires and physiological parameters based on basic information, lifestyle habits, work situation, and emotional stress.

RESULTS

The results showed that all of the eight major classes of lipids had the highest expression in the D2 group, with the largest differences in glycerophospholipids, glycerol esters, and fatty acids. The BMI value of D2 group was higher than that of D1 group, the skin elasticity index (R2) and brightness index (L, a, ITA values) were lower than that of D1 group, and Cer (d18:0/16:0) was positively correlated with the R2, L, a, and ITA, and LMSP01080056 (N,N-dimethyl-Safingol) was positively correlated with the b-value, the LMSPGP03020013, LMSPGP03020014, LMSP03020024 were significantly negatively correlated with R2.

CONCLUSIONS

Cer(d18:0/16:0) is a neurosphingol that inhibits elastase expression. N,N-dimethyl-Safingol readily undergoes oxidation to form yellow-brown solids. The macromolecular structure and excessive carbonyl structure of [LMGP0302] are susceptible to cross-linking and carbonyl stress reactions, which accelerate skin aging and reduce skin elasticity, and thus, they may be key lipids contributing to skin differences between the two age groups.

Comparison between ammonium formate and ammonium fluoride in the analysis of stratum corneum lipids by reversed phase chromatography coupled with high resolution mass spectrometry

Lipids are key constituents of the barrier function in the human stratum corneum (SC), which is the outermost layer of the epidermis and amenable to non-invasive sampling by tape stripping. The three major lipid classes in the SC, i.e., ceramides, fatty acids, and cholesterol, present equimolar concentration. Liquid chromatography coupled with mass spectrometry (LCMS) is elective in profiling lipids in the SC in both positive and negative ion modes. Nevertheless, the latter one allows for the simultaneous detection of the three major epidermal components of the SC. Determination of ceramides in the SC poses analytical challenges due to their wide range of structures and concentrations especially in the case of limited sample amounts. Ammonium formate is a commonly used modifier added to the mobile phase to assist ionization. However, it introduces uncertainty in the identification of ceramides when operating in negative ion mode, even with high resolution MS. We tested the advantages of using fluoride in the lipid profiling of SC and unambiguous identification of ceramides subclasses. The use of fluoride enhanced the ionization of ceramides, regardless the specific substructure, solved misidentification issues, and was successfully applied to the simultaneous detection of all three lipid classes in the human SC.

The impacts of biologic treatment on metabolic profiling in psoriasis

Psoriasis is an immune-mediated inflammatory disease commonly accompanied by various metabolic disorders. It is widely known that biologics could affect the metabolic status and comorbidities in psoriasis patients, however, the effects of biologics on metabolism in psoriasis patients remain poorly understood. The aim of this study was to elucidate the characteristic changes of metabolic profiling in psoriasis vulgaris (PsV) patients before and after applying biologics. Plasma samples were collected from a retrospective cohort of 43 PsV patients. Non-targeted metabolomics analyses were performed using liquid chromatography-mass spectrometry (LC-MS) to compare the metabolic profiles before and after applying adalimumab (ADA) or ixekizumab (IXE) for 4 weeks. Additionally, correlation analyses were conducted to investigate the associations between metabolite expression levels and clinical characteristics. The biologics significantly affected the metabolic profiles of PsV patients especially in glycerophospholipids (GPs). First, phosphatidylcholine (PC), unsaturated lysophosphatidylcholine (LPC), unsaturated lysophosphatidic acid (LPA) and unsaturated lysophosphatidylethanolamine (LPE) were significantly up-regulated, whereas phosphatidylethanolamine (PE), saturated LPC, saturated LPA and saturated LPE were predominantly down-regulated after biologic treatment. What is more, the changes in PE and LPA were mainly observed after applying IXE instead of ADA. Second, we also found GPs including PC, unsaturated LPC, unsaturated LPA and unsaturated LPE were primarily negatively correlated with disease severity, whereas, PE, saturated LPC, saturated LPA and saturated LPE displayed inverse correlations. Biologics could affect GP metabolism and facilitate the transition of metabolic status from a pro-inflammatory to an anti-inflammatory phenotype in PsV patients.

The identification of novel stroke-related sphingolipid biomarkers using UPLC-MS/MS

BACKGROUND

Stroke is a prominent contributor to global mortality and morbidity, thus necessitating the establishment of dependable diagnostic indicators. The objective of this study was to ascertain metabolites linked to sphingolipid metabolism and assess their viability as diagnostic markers for stroke.

METHODS

Two cohorts, consisting of 56 S patients and 56 healthy volunteers, were incorporated into this investigation. Metabolite data was obtained through the utilization of Ultra Performance Liquid Chromatography and Tandem Mass Spectrometry (UPLC-MS/MS). The mass spectrometry data underwent targeted analysis and quantitative evaluation utilizing the multiple reaction monitoring mode of triple quadrupole mass spectrometry. Various data analysis techniques, including Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA), least absolute shrinkage and selection operator (LASSO) regression, Support Vector Machine (SVM), logistic regression, and Receiver Operating Characteristic (ROC) curves were employed.

RESULTS

A comprehensive analysis detected a total of 129 metabolites related to sphingolipid metabolism, encompassing ceramides, 1-phosphoceramides, phytoceramides, glycosphingolipids, sphingomyelins, and sphingomyelins. The implementation of OPLS-DA analysis revealed significant disparities between individuals with stroke and controls, as it successfully identified 31 metabolites that exhibited significant differential expression between the two groups. Furthermore, functional enrichment analysis indicated the participation of these metabolites in diverse biological processes. Six metabolic markers, namely CerP(d18:1/20:3), CerP(d18:1/18:1), CerP(d18:1/18:0), CerP(d18:1/16:0), SM(d18:1/26:1), and Cer(d18:0/20:0), were successfully validated as potential diagnostic markers for stroke. The utilization of ROC analysis further confirmed their diagnostic potential, while a logistic regression model incorporating these markers demonstrated robust efficacy in distinguishing stroke patients from healthy controls.

CONCLUSION

these identified metabolic markers exhibit clinical significance and hold promise as valuable tools for the diagnosis of stroke.

Recent advances in understanding the role of the skin microbiome in the treatment of atopic dermatitis

The skin is the largest organ in the human body, and histologically consists of the epidermis, dermis and subcutaneous tissue. Humans maintain a cooperative symbiotic relationship with their skin microbiota, a complex community of bacteria, fungi and viruses that live on the surface of the skin, and which act as a barrier to protect the body from the inside and outside. The skin is a 'habitat' and vast 'ecosystem' inhabited by countless microbes; as such, relationships have been forged through millions of years of coevolution. It is not surprising then that microbes are key participants in shaping and maintaining essential physiological processes. In addition to maintaining barrier function, the unique symbiotic microbiota that colonizes the skin increases the immune response and provides protection against pathogenic microbes. This review examines our current understanding of skin microbes in shaping and enhancing the skin barrier, as well as skin microbiome-host interactions and their roles in skin diseases, such as atopic dermatitis (AD). We also report on the current status of AD therapeutic drugs that target the skin microbiome, related research on current therapeutic strategies, and the limitations and future considerations of skin microbiome research. In particular, as a future strategy, we discuss the need for a skin-on-a-chip-based microphysiological system research model amenable to biomimetic in vitro studies and human skin equivalent models, including skin appendages.

The Design and Optimization of Ceramide NP-Loaded Liposomes to Restore the Skin Barrier

The impairment of skin integrity derived from derangement of the orthorhombic lateral organization is mainly caused by dysregulation of ceramide amounts in the skin barrier. Ceramides, fatty acids, and cholesterol-containing nano-based formulations have been used to impair the skin barrier. However, there is still a challenge to formulate novel formulations consisting of ceramides due to their chemical structure, poor aqueous solubility, and high molecular weight. In this study, the design and optimization of Ceramide 3 (CER-NP)-loaded liposomes are implemented based on response surface methodology (RSM). The optimum CER-NP-loaded liposome was selected based on its particle size (PS) and polydispersity index (PDI). The optimum CER-NP-loaded liposome was imagined by observing the encapsulation by using a confocal laser scanning microscope (CLSM) within fluorescently labeled CER-NP. The characteristic liquid crystalline phase and lipid chain conformation of CER-NP-loaded liposomes were determined using attenuated total reflectance infrared spectroscopy (ATR-IR). The CER-NP-loaded liposomes were imagined using a field emission scanning electron microscope (FE-SEM). Finally, the in vitro release of CER-NP from liposomes was examined using modified Franz Cells. The experimental and predicted results were well correlated. The CLSM images of optimized liposomes were conformable with the other studies, and the encapsulation efficiency of CER-NP was 93.84 ± 0.87%. ATR-IR analysis supported the characteristics of the CER-NP-loaded liposome. In addition, the lipid chain conformation shows similarity with skin barrier lipid organization. The release pattern of CER-NP liposomes was fitted with the Korsmeyer-Peppas model. The cytotoxicity studies carried out on HaCaT keratinocytes supported the idea that the liposomes for topical administration of CER-NP could be considered relatively safe. In conclusion, the optimized CER-NP-loaded liposomes could have the potential to restore the skin barrier function.

Characterization of Epidermal Function in Individuals with Primary Cutaneous Amyloidosis

Purpose

To compare epidermal biophysical properties, indicators of epidermal function, in individuals with and without primary cutaneous amyloidosis (PCA).

Patients and Methods

This study incorporated 189 patients with PCA and 166 healthy individuals. The GPSkin Barrier was employed to measure transepidermal water loss (TEWL) rates and hydration levels of the stratum corneum. The Sebumeter and the Skin pH Meter were utilized to determine the skin surface's sebum content and pH, respectively. The severity of pruritus in participants was evaluated using the visual analog scale (VAS).

Results

Compared to the control group without PCA, individuals with PCA displayed a notable increase in skin surface pH and TEWL and a decrease in the hydration levels of the stratum corneum (p<0.0001 for all parameters). Additionally, the sebum content was markedly lower in those with PCA than in the controls (p<0.0001). Of particular note, both TEWL and skin surface pH at the lesion sites on the back and the shin were more elevated in lichenoid amyloidosis (LA) and in macular amyloidosis (MA), whereas hydration levels of the stratum corneum and sebum levels were diminished in LA compared to MA (p<0.05). In conclusion, both hydration levels of the stratum corneum and sebum content exhibited an inverse relationship with pruritus severity, whereas TEWL and skin surface pH demonstrated a positive correlation with pruritus intensity.

Conclusion

The function of the epidermis is compromised in individuals diagnosed with PCA. However, the mechanisms underlying these changes await further investigation.

Bifidobacterium longum 68S mediated gut-skin axis homeostasis improved skin barrier damage in aging mice

BACKGROUND

Bifidobacterium as probiotics, play important roles in skin status, while the potential mechanisms interaction remains unknown. The study further explored the potential mechanism of B. longum 68S in ameliorating skin barrier damage from the perspective of the gut-skin axis in aging mice.

METHODS

B. longum 68S supplied natural aging mouse model and fecal microbiota transplantation (FMT) experiment proves the key role of intestinal microbiota in B. longum 68S up-regulating the production of ceramide synthesis key enzyme (SPT1) and ceramide level and improving skin barrier damage. Moreover, B. longum 68S supplied SPT1 gene deletion mouse model to investigate the mechanism of B. longum 68S on improving skin barrier damage.

RESULTS

Transcriptome analysis and 16S rRNA high-throughput pyrosequencing demonstrated that aging mice exhibited skin barrier dysfunction and intestinal dysbiosis. Meanwhile, aging mice exhibited an up-regulation in the trans epidermal water loss (TEWL) and a down-regulation in the level of SPT1, ceramide and skin barrier-related proteins (Loricrin, Keratin 10 and Desmoglein 1). Similarity, the FMT from aging mice to normal mice and SPT1 gene deletion mice could rebuild skin barrier damage and B. longum 68S supplementation exerted a positive effect on it. Further, B. longum 68S-mediated SPT1-derived ceramide production prevented impaired ceramide synthesis-induced endoplasmic reticulum stress and apoptotic response, ultimately improving skin barrier damage in vitro.

CONCLUSION

Emerging anti-aging therapies are necessary given the poor safety profiles of current pharmaceutical drugs. B. longum 68S may be better alternatives, considering the association between the gut microbiota and healthy aging. The findings suggested that B. longum 68S-mediated gut-skin axis homeostasis, thereby exhibiting an anti-aging effect and facilitate a better understanding of the mechanisms governing the various beneficial effects of B. longum 68S.

Plant exosomes fused with engineered mesenchymal stem cell-derived nanovesicles for synergistic therapy of autoimmune skin disorders

Existing therapeutics for autoimmune diseases remain problematic due to low efficacy, severe side effects, and difficulties to reach target tissues. Herein, we design multifunctional fusion nanovesicles that can target lesions for the treatment of autoimmune skin diseases. The grapefruit-derived exosome-like nanovesicles (GEVs) with anti-inflammatory and antioxidant effects are first encapsulated with CX5461, an immunosuppressant with anti-proliferative properties to form GEV@CX5461. In order to enhance therapeutic efficiency and safety, GEV@CX5461 are then fused with CCR6+ nanovesicles derived from membranes of engineered gingiva-derived mesenchymal stem cells (GMSCs). The resulting FV@CX5461 not only maintain the bioactivity of GEVs, CX5461, and GMSC membranes but also home to inflamed tissues rich in chemokine CCL20 through the chemotaxis function of CCR6 on FVs. Moreover, FV@CX5461 reduce the secretion of inflammatory factors, calm down Th17 cell activation, and induce Treg cell infiltration. Finally, impressive therapeutic efficiency in both psoriasis and atopic dermatitis disease models is demonstrated using FV@CX5461 to reshape the unbalanced immune microenvironment. A nanotherapeutic drug delivery strategy is developed using fusion nanovesicles derived from plant and animal cells with high clinical potential.

Altered structure indicating reduced barrier function of lesional compared to non-lesional psoriatic skin-A non-invasive in vivo study of the human stratum corneum with confocal Raman micro-spectroscopy

Psoriasis, one of the most common skin diseases affecting roughly 2%-3% of the world population, is associated with a reduced skin barrier function (SBF) that might play an important role in its pathophysiology. The SBF is provided primarily by the stratum corneum (SC) of the skin. Previous studies have revealed a higher trans-epidermal water loss, lower hydration, abnormal concentration and composition of intercellular lipids, as well as alterations in secondary keratin structure in the psoriatic SC. We compared on molecular level lesional psoriatic skin (LPS) with non-lesional psoriatic skin (nLPS) from 19 patients non-invasively in vivo, using confocal Raman micro-spectroscopy. By analysing the corresponding Raman spectra, we determined SBF-defining parameters of the SC depth-dependently. Our results revealed a lower total lipid concentration, a shift of lamellar lipid organisation towards more gauche-conformers and an increase of the less dense hexagonal lateral packing of the intercellular lipids in LPS. Furthermore, we observed lower natural moisturising factor concentration, lower total water as well as a strong tendency towards less strongly bound and more weakly bound water molecules in LPS. Finally, we detected a less stable secondary keratin structure with increased β-sheets, in contrast to the tertiary structure, showing a higher degree of folded keratin in LPS. These findings clearly suggest structural differences indicating a reduced SBF in LPS, and are discussed in juxtaposition to preceding outcomes for psoriatic and healthy skin. Understanding the alterations of the psoriatic SC provides insights into the exact pathophysiology of psoriasis and paves the way for optimal future treatments.

Atopic Dermatitis: Molecular Alterations between Lesional and Non-Lesional Skin Determined Noninvasively by In Vivo Confocal Raman Microspectroscopy

Atopic dermatitis (AD)/atopic eczema is a chronic relapsing inflammatory skin disease affecting nearly 14% of the adult population. An important pathogenetic pillar in AD is the disrupted skin barrier function (SBF). The atopic stratum corneum (SC) has been examined using several methods, including Raman microspectroscopy, yet so far, there is no depth-dependent analysis over the entire SC thickness. Therefore, we recruited 21 AD patients (9 female, 12 male) and compared the lesional (LAS) with non-lesional atopic skin (nLAS) in vivo with confocal Raman microspectroscopy. Our results demonstrated decreased total intercellular lipid and carotenoid concentrations, as well as a shift towards decreased orthorhombic lateral lipid organisation in LAS. Further, we observed a lower concentration of natural moisturising factor (NMF) and a trend towards increased strongly bound and decreased weakly bound water in LAS. Finally, LAS showed an altered secondary and tertiary keratin structure, demonstrating a more folded keratin state than nLAS. The obtained results are discussed in comparison with healthy skin and yield detailed insights into the atopic SC structure. LAS clearly shows molecular alterations at certain SC depths compared with nLAS which imply a reduced SBF. A thorough understanding of these alterations provides useful information on the aetiology of AD and for the development/control of targeted topical therapies.

Detection of Bacterial Neutral Ceramidase in Diabetic Foot Ulcers with an Optimized Substrate and Chemoenzymatic Probes

Ceramidases (CDases) are important in controlling skin barrier integrity by regulating ceramide composition and affording downstream signal molecules. While the functions of epidermal CDases are known, roles of neutral CDases secreted by skin-residing microbes are undefined. Here, we developed a one-step fluorogenic substrate, S-B, for specific detection of bacterial CDase activity and inhibitor screening. We identified a non-hydrolyzable substrate mimic, C6, as the best hit. Based on C6, we designed a photoaffinity probe, JX-1, which efficiently detects bacterial CDases. Using JX-1, we identified endogenous low-abundance PaCDase in a P. aeruginosa monoculture and in a mixed skin bacteria culture. Harnessing both S-B and JX-1, we found that CDase activity positively correlates with the relative abundance of P. aeruginosa and is negatively associated with wound area reduction in clinical diabetic foot ulcer patient samples. Overall, our study demonstrates that bacterial CDases are important regulators of skin ceramides and potentially play a role in wound healing.

Bioprospecting the Skin Microbiome: Advances in Therapeutics and Personal Care Products

Bioprospecting is the discovery and exploration of biological diversity found within organisms, genetic elements or produced compounds with prospective commercial or therapeutic applications. The human skin is an ecological niche which harbours a rich and compositional diversity microbiome stemming from the multifactorial interactions between the host and microbiota facilitated by exploitable effector compounds. Advances in the understanding of microbial colonisation mechanisms alongside species and strain interactions have revealed a novel chemical and biological understanding which displays applicative potential. Studies elucidating the organismal interfaces and concomitant understanding of the central processes of skin biology have begun to unravel a potential wealth of molecules which can exploited for their proposed functions. A variety of skin-microbiome-derived compounds display prospective therapeutic applications, ranging from antioncogenic agents relevant in skin cancer therapy to treatment strategies for antimicrobial-resistant bacterial and fungal infections. Considerable opportunities have emerged for the translation to personal care products, such as topical agents to mitigate various skin conditions such as acne and eczema. Adjacent compound developments have focused on cosmetic applications such as reducing skin ageing and its associated changes to skin properties and the microbiome. The skin microbiome contains a wealth of prospective compounds with therapeutic and commercial applications; however, considerable work is required for the translation of in vitro findings to relevant in vivo models to ensure translatability.

Barrier function and ultrastructure characteristics of epidermis in patients with primary cutaneous amyloidosis

Previous studies on primary cutaneous amyloidosis (PCA) have mainly focused on exploring genetic mutation and components of amyloid in patients with PCA. However, studies on skin barrier function in PCA patients are scarce. Here, we detected the skin barrier function in PCA patients and healthy people by using noninvasive techniques and characterized ultrastructural features of PCA lesions compared with healthy people using transmission electron microscopy (TEM). The expression of proteins related to skin barrier function was examined by immunohistochemistry staining. A total of 191 patients with clinically diagnosed PCA and 168 healthy individuals were enrolled in the study. Our analysis revealed that all investigated lesion areas displayed higher transepidermal water loss and pH values, and lower Sebum levels and stratum corneum hydration levels in PCA patients compared with the same site area in healthy individuals. The TEM results showed that the intercellular spaces between the basal cells were enlarged and the number of hemidesmosomes decreased in PCA lesions. Immunohistochemical staining showed that the expression of integrin α6 and E-cadherin in PCA patients was less than that in healthy controls, while no differences in the expression of loricrin and filaggrin were observed. Our study revealed that individuals with PCA displayed skin barrier dysfunction, which may be related to alterations in epidermal ultrastructure and a decrease in the skin barrier-related protein E-cadherin. However, the molecular mechanisms underlying skin barrier dysfunction in PCA remain to be elucidated.

Effects of probiotics supplementation on skin photoaging and skin barrier function: A systematic review and meta-analysis

BACKGROUND

Ultraviolet (UV) irradiation is one of the major causes of skin aging. To date, there remains limited evidence on using oral probiotics for skin anti-photoaging.

OBJECTIVES

This systematic review and meta-analysis aims to assess the effects of probiotics on skin photoaging.

METHODS

We searched the PubMed and Embase databases for studies published until August 31, 2021, and included randomized controlled trials, murine randomized controlled experiments, and in vitro studies. Skin barrier function was compared between UV irradiated probiotics and controls.

RESULTS

After given oral probiotics supplements, a significant reduction was shown in all types of measured MMPs in both murine and in vitro studies. Oral probiotics supplementation significantly reversed UV-induced increase of epidermal thickness (standardized mean differences [SMD] = -1.76; 95% confidence interval [CI] = -3.04 to -0.49; p = .007; I²  = 81%), UV-induced increase trans-epidermal water loss (SMD = -1.72; 95% CI = -2.76 to -0.67; p = .001; I²  = 57%), and UV-induced skin dehydration (SMD = 1.85; 95% CI = 1.16 to 2.55; p < .00001; I²  = 4%).

CONCLUSIONS

Probiotics are effective against skin photoaging in terms of MMP pathways and reversing skin barrier function from murine randomized data. Further randomized controlled trials on humans are required to warrant these results.

Progress of metabolomics in atopic dermatitis: a systematic review

Atopic dermatitis (AD), a chronic inflammatory skin disorder characterized by recurrent eczema and intense pruritus, is a major skin-related burden worldwide. The diagnosis and treatment of AD is often challenging due to the high heterogeneity of AD, and its exact etiology is unknown. Metabolomics offers the opportunity to follow continuous physiological and pathological changes in individuals, which allows accurate diagnosis and management as well as providing deep insights into the etiopathogenesis of AD. Several metabolomic studies of AD have been published over the past few years. The aim of this review is to summarize these findings and help researchers to understand the rapid development of metabolomics for AD. A comprehensive and systematic search was performed using the PubMed, Embase, Cochrane Library and Web of Science databases. Twenty-six papers were finally included in the review after quality assessment. Significant differences in metabolite profiles were found between patients with AD and healthy individuals. This study provides a comprehensive overview of metabolomic research in AD. A better understanding of the metabolomics of AD may offer novel diagnostic, prognostic, and therapeutic approaches.

Head and neck dermatitis is exacerbated by Malassezia furfur colonization, skin barrier disruption, and immune dysregulation

Introduction & objectives

Head and neck dermatitis (HND) is a refractory phenotype of atopic dermatitis (AD) and can be a therapeutic challenge due to lack of responsiveness to conventional treatments. Previous studies have suggested that the microbiome and fungiome may play a role in inducing HND, but the underlying pathogenic mechanisms remain unknown. This study aimed to determine the link between HND and fungiome and to examine the contribution of Malassezia furfur.

Materials and methods

To identify the effect of the sensitization status of M. furfur on HND, 312 patients diagnosed with AD were enrolled. To elucidate the mechanism underlying the effects of M. furfur, human keratinocytes and dermal endothelial cells were cultured with M. furfur and treated with Th2 cytokines. The downstream effects of various cytokines, including inflammation and angiogenesis, were investigated by real-time quantitative PCR. To identify the association between changes in lipid composition and M. furfur sensitization status, D-squame tape stripping was performed. Lipid composition was evaluated by focusing on ceramide species using liquid chromatography coupled with tandem mass spectrometry.

Results

Increased sensitization to M. furfur was observed in patients with HND. Additionally, sensitization to M. furfur was associated with increased disease severity in these patients. IL-4 treated human keratinocytes cultured with M. furfur produced significantly more VEGF, VEGFR, IL-31, and IL-33. IL-4/M. furfur co-cultured dermal endothelial cells exhibited significantly elevated VEGFR, TGF-β, TNF-α, and IL-1β levels. Stratum corneum lipid analysis revealed decreased levels of esterified omega-hydroxyacyl-sphingosine, indicating skin barrier dysfunction in HND. Finally, M. furfur growth was inhibited by the addition of these ceramides to culture media, while the growth of other microbiota, including Cutibacterium acnes, were not inhibited.

Conclusions

Under decreased levels of ceramide in AD patients with HND, M. furfur would proliferate, which may enhance pro-inflammatory cytokine levels, angiogenesis, and tissue remodeling. Thus, it plays a central role in the pathogenesis of HND in AD.

Abnormalities of Sphingolipids Metabolic Pathways in the Pathogenesis of Psoriasis

Psoriasis is immune-mediated skin disorder affecting thousands of people. Sphingolipids (SLs) are bioactive molecules present in the epidermis, involved in the following cellular processes: proliferation, differentiation, and apoptosis of keratinocytes. Alterations in SLs synthesis have been observed in psoriatic skin. To investigate if the imbalance in lipid skin metabolism could be related to psoriasis, we analyzed the gene expression in non-lesioned and lesioned skin of patients with psoriasis available in two datasets (GSE161683 and GSE136757) obtained from National Center for Biotechnology Information (NCBI). The differentially expressed genes (DEGs) were searched for using NCBI analysis, and Gene Ontology (GO) biological process analyses were performed using the Database of Annotation, Visualization, and Integrated Discovery (DAVID) platform. Venn diagrams were done with InteractiVenn tool and heatmaps were constructed using Morpheus software. We observed that the gene expression of cytoplasmic phospholipase A₂ (PLA2G4D), glycerophosphodiester phosphodiesterase domain containing 3 (GDP3), arachidonate 12-lipoxygenase R type (ALOX12B), phospholipase B-like 1 (PLBD1), sphingomyelin phosphodiesterase 3 (SMPD3), ganglioside GM2 activator (GM2A), and serine palmitoyltransferase long chain subunit 2 (SPTLC2) was up-regulated in lesioned skin psoriasis when compared with the non-lesioned skin. These genes are related to lipid metabolism and more specifically to sphingolipids. So, in the present study, the role of sphingolipids in psoriasis pathogenesis is summarized. These genes could be used as prognostic biomarkers of psoriasis and could be targets for the treatment of patients who suffer from the disease.

Lipidomic Analysis of Hand Skin Surface Lipids Reveals Smoking-Related Skin Changes

Smoking contributes to the formation of skin wrinkles and reduces skin function, but the mechanism is not yet fully proven. This study aims to compare and analyze the effects of smoking on skin lipids and to further investigate the harmful effects of smoking on the skin. A total of 40 subjects (20 male smokers and 20 healthy control males) were recruited for this study. Measurement of hand skin-surface lipids (SSLs) in smoking and healthy control groups was undertaken using ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). Multivariate data analysis was used to investigate the differences in SSLs between the two groups. There were 1230 lipids detected in the two groups and significant differences in SSLs' composition were observed between them. Under selected conditions, 26 types of lipid with significant differences were observed between the two groups (p < 0.05). Sphingolipids (SP) and glycerolipids (GL) were significantly increased, and sterol lipids (ST) were significantly reduced. Smoking causes changes in skin lipids that disrupt skin homeostasis, making the skin more fragile and more susceptible to skin aging and diseases.

The interaction of CD300lf and ceramide reduces the development of periodontitis by inhibiting osteoclast differentiation

AIM

The regulation of osteoclasts (OCs) by inhibitory immunoreceptors maintains bone homeostasis and is considered an important determinant of the extent of periodontal pathology. The aim of this study was to investigate the role of the inhibitory immunoreceptor CD300lf and its ligand ceramide in osteoclastogenesis in periodontitis.

MATERIALS AND METHODS

The expression of CD300lf was measured in vitro and in a ligature-induced periodontitis model. The effect of CD300lf ablation on osteoclastogenesis was examined in ligature-retained and ligature removal periodontitis models. The effect of ceramide, the ligand of CD300lf, was examined in osteoclastogenesis in vitro and in vivo by smearing 20 μg of ceramide dissolved in carboxymethylcellulose on teeth and gingiva every other day in an experimental periodontitis model and ligature removal model.

RESULTS

CD300lf expression was downregulated during osteoclastogenesis. Ablation of CD300lf in the ligature-induced periodontitis model increased the number of OCs and exacerbated bone damage. Bone resorption caused by CD300lf ablation was reversible following ligature removal. CD300lf-ceramide binding suppressed osteoclastogenesis in vitro and inhibited alveolar bone loss in a mouse periodontitis model.

CONCLUSIONS

Our findings reveal that CD300lf-ceramide binding plays a critical negative role in alveolar bone loss in periodontitis by inhibiting OCs differentiation.

A method for quantifying hepatic and intestinal ceramides on mice by UPLC-MS/MS

BACKGROUND

Ceramide is one type of sphingolipids, is associated with the occurrence of metabolic diseases, including obesity, diabetes, cardiovascular disease, cancer, and nonalcoholic fatty liver disease. Dihydroceramide, the direct precursors of ceramide, which is converted to ceramide with the dihydroceramide desaturase, is recently regarded as involving in various biological processes and metabolic diseases. The liver and gut ceramide levels are interactional in pathophysiological condition, quantifying hepatic and intestinal ceramide levels become indispensable. The aim of this study is to establish a rapid method for the determination of ceramides including dihydroceramides in liver and small intestinal tissues for researching the mechanisms of ceramide related diseases.

METHODS

The levels of Cer d18:1/2:0, Cer d18:1/6:0, Cer d18:1/12:0, Cer d18:1/14:0, Cer d18:1/16:0, Cer d18:1/17:0, Cer d18:1/18:0, Cer d18:1/20:0, Cer d18:1/22:0, Cer d18:1/24:1, Cer d18:1/24:0, dHCer d18:0/12:0, dHCer d18:0/14:0, dHCer d18:0/16:0, dHCer d18:0/18:0, dHCer d18:0/24:1 and dHCer d18:0/24:0 in mice liver and small intestine were directly quantified by ultra-high performance liquid chromatography-tandem mass spectrometry after methanol extraction. In detail, liver or small intestine tissues were thoroughly homogenized with methanol. The resultant ceramides were separated on a Waters BEH C18 column using gradient elution within 10 min. Positive electrospray ionization with multiple reaction monitoring was applied to detect. In the end, the levels of ceramides in mice liver and small intestine tissues were quantified by this developed method.

RESULTS

The limits of detection and quantification of 11 ceramides and 6 dihydroceramides were 0.01-0.5 ng/mL and 0.02-1 ng/mL, respectively, and all detected ceramides had good linearities (R² > 0.997). The extraction recoveries of ceramides at three levels were within 82.32%-115.24% in the liver and within 83.21%-118.70% in the small intestine. The relative standard deviations of intra- and inter-day precision were all within 15%. The extracting solutions of the liver and small intestine could be stably stored in the autosampler 24 h at 10 °C, the lyophilized liver and small intestine for ceramides quantification could be stably stored at least 1 week at -80 °C. The ceramides and dihydroceramides in normal mice liver and small intestinal tissues analyzed by the developed method indicated that the detected 9 ceramide and 5 dihydroceramides levels were significantly different, in which Cer d18:1/16:0, Cer d18:1/22:0, Cer d18:1/24:1, Cer d18:1/24:0 and dHCer d18:0/24:1 are the main components in the liver, whereas Cer d18:1/16:0 and dHCer d18:0/16:0 accounts for the majority of proportion in the intestinal tissues.

CONCLUSION

A simple and rapid method for the quantification of 11 ceramides and 6 dihydroceramides in the animal tissues was developed and applied. The compositions of ceramides in two tissues suggested that the compositional features should to be considered when exploring the biomarkers or molecular mechanisms.

Lipidomic analysis reveals the effect of passive smoking on facial skin surface lipid in females

BACKGROUND

Smoking has toxic effects on the skin and can damage it. However, few studies have focused on the lipid profile changes of facial skin surface lipids (SSL) by passive smoking.

METHOD

A cross-sectional analytical study was conducted on middle-aged females volunteered from Henan, China to participate in the study. A total of 20 passive smoking females and 20 non-passive smoking females were recruited for this study. The components of skin surface lipids were measured by ultra-performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-QTOF-MS). Multivariate data analysis and enrichment analysis were used to investigate the differences in facial SSL between passive and non-passive smoking females.

RESULT

There were 1247 lipid entities identified in facial SSL between passive and non-passive smoking females. Significant differences in composition of facial SSL were observed between the two groups. After multivariate data analysis suggested, 28 significantly different lipids were identified and classified into four classes in SSL of the female cheeks. As well as 32 significantly different lipids were obtained in SSL of the female foreheads, which included three classes of lipids. Subsequent analysis revealed that the content of fatty acids (FA) in passive smoking females was significantly reduced and the content of glycerolipids (GL) and sphingolipids (SP) increased, compared with the control group.

CONCLUSION

These results indicated that an increase in GLs and SPs of facial lipids and a decrease in FAs in passive smoking females. These changes in lipids might be associated with oxidative stress and interference with signaling pathways by substances in smoke. And passive smoking affected facial SSL and changed the content and metabolism of skin lipids.

Effect of Rice (Oryza sativa L.) Ceramides Supplementation on Improving Skin Barrier Functions and Depigmentation: An Open-Label Prospective Study

Ceramides plays a crucial role in maintaining skin barrier function. Although foregoing evidence supported beneficial effects of topical ceramides for restoration of the skin barrier, studies on oral ceramides are extremely scarce, with most published data collected from in vivo and in vitro models. Thus, this study aimed to evaluate the efficacy of rice ceramides (RC) supplementation to improve skin barrier function and as a depigmenting agent through comprehensive clinical assessments. This study investigated the beneficial effects of orally administered RC supplementation in 50 voluntary participants. Skin hydration, firmness and elasticity, transepidermal water loss (TEWL), melanin index (MI), erythema index (EI), sebum production, pH, and wrinkle severity were assessed at baseline and during monthly follow-up visits. RC supplementation was found to significantly (p < 0.01) improve skin hydration, sebum production, firmness and elasticity, and wrinkle severity for three assessed areas, namely the left cheek, dorsal neck, and right inner forearm. Additionally, RC significantly (p < 0.01) reduced the rates of TEWL, levels of MI and EI. Analyses of data indicated that participants at older age were more responsive towards the effect of RC supplementation. Our findings suggest that RC supplementation can effectively improve skin barrier function, reduce wrinkle severity, and reduce pigmentation.

Application of nanotechnology in management and treatment of diabetic wounds

Diabetic wounds are one of the most common health problems worldwide, enhancing the demand for new management strategies. Nanotechnology, as a developing subject in diabetic wound healing, is proving to be a promising and effective tool in treatment and care. It is, therefore, necessary to ascertain the available and distinct nanosystems and evaluate their performance when topically applied to the injury site, especially in diabetic wound healing. Several active ingredients, including bioactive ingredients, growth factors, mesenchymal stem cells, nucleic acids, and drugs, benefit from improved properties when loaded into nanosystems. Given the risk of problems associated with systemic administration, the topical application should be considered, provided stability and efficacy are assured. After nanoencapsulation, active ingredients-loaded nanosystems have been showing remarkable features of biocompatibility, healing process hastening, angiogenesis, and extracellular matrix compounds synthesis stimulation, contributing to a decrease in wound inflammation. Despite limitations, nanotechnology has attracted widespread attention in the scientific community and seems to be a valuable technological ally in the treatment and dressing of diabetic wounds. The use of nanotechnology in topical applications enables efficient delivery of the active ingredients to the specific skin site, increasing their bioavailability, stability, and half-life time, without compromising their safety.

The Role of Sphingolipids in Allergic Disorders

Allergy is defined as a complex chronic inflammatory condition in which genetic and environmental factors are implicated. Sphingolipids are involved in multiple biological functions, from cell membrane components to critical signaling molecules. To date, sphingolipids have been studied in different human pathologies such as neurological disorders, cancer, autoimmunity, and infections. Sphingolipid metabolites, in particular, ceramide and sphingosine-1-phosphate (S1P), regulate a diverse range of cellular processes that are important in immunity and inflammation. Moreover, variations in the sphingolipid concentrations have been strongly associated with allergic diseases. This review will focus on the role of sphingolipids in the development of allergic sensitization and allergic inflammation through the activation of immune cells resident in tissues, as well as their role in barrier remodeling and anaphylaxis. The knowledge gained in this emerging field will help to develop new therapeutic options for allergic disorders.

Effects of the epidermal growth factor receptor inhibitor, gefitinib, on lipid and hyaluronic acid synthesis in cultured HaCaT keratinocytes

Epidermal growth factor receptor inhibitors (EGFRIs) are widely used for treating various cancers, including lung, colon, head and neck cancers. However, EGFRIs have unique dermatological side effects, including acneiform eruption, dry skin, paronychias, and pruritus. In this study, we investigated the molecular changes induced by an EGFRI, gefitinib, in the expression of lipogenic enzymes and hyaluronic acid (HA) regulatory proteins in HaCaT keratinocytes, and whether EGF restored these changes. HaCaT cells were treated with gefitinib, with or without EGF, and treated with tumor necrosis factor α (TNFα) for inducing an inflammatory response. The mRNA and protein expression was analyzed by real-time RT-PCR, enzyme-linked immunosorbent assay (ELISA), and western blotting. Gefitinib enhanced the TNFα-induced expression of C-C motif chemokine ligand 2 (CCL2), CCL5, and C-X-C motif chemokine ligand 10 (CXCL10), and the expression of TNFα in HaCaT cells, while EGF restored these changes. At a similar concentration range, gefitinib reduced the mRNA and/or protein expression of various lipogenic enzymes for fatty acid, cholesterol, and ceramide synthesis, except acidic sphingomyelinase. Gefitinib suppressed the mRNA and protein expression of HA synthase 2 (HAS2), HAS3, cluster of differentiation 44 (CD44), hyaluronidase 1 (HYAL1), and HYAL2, except the mRNA expression of HYAL1. EGF restored the changes induced by gefitinib, except for the mRNA expression of fatty acid synthase (FASN) and elongation of very long chain fatty acids protein (ELOVL) 6. In conclusion, EGFRIs suppress lipogenesis and HA metabolism, which may contribute to adverse dermatological effects, including barrier function impairment in cancer patients treated with EGFRIs.

Performance of Oleic Acid and Soybean Oil in the Preparation of Oil-in-Water Microemulsions for Encapsulating a Highly Hydrophobic Molecule

This work analyzes the dispersion of a highly hydrophobic molecule, (9Z)-N-(1,3-dihydroxyoctadecan-2-yl)octadec-9-enamide (ceramide-like molecule), with cosmetic and pharmaceutical interest, by exploiting oil-in-water microemulsions. Two different oils, oleic acid and soybean oil, were tested as an oil phase while mixtures of laureth-5-carboxylic acid (Akypo) and 2-propanol were used for the stabilization of the dispersions. This allowed us to obtain stable aqueous-based formulations with a relatively reduced content of oily phase (around 3% w/w), that may enhance the bioavailability of this molecule by its solubilization in nanometric oil droplets (with a size range of 30–80 nm), that allow the incorporation of a ceramide-like molecule of up to 3% w/w, to remain stable for more than a year. The nanometric size of the droplet containing the active ingredient and the stability of the formulations provide the basis for evaluating the efficiency of microemulsions in preparing formulations to enhance the distribution and availability of ceramide-like molecules, helping to reach targets in cosmetic and pharmaceutical formulations.

Accelerated Barrier Repair in Human Skin Explants Induced with a Plant-Derived PPAR-α Activating Complex via Cooperative Interactions

Background

Peroxisome proliferator-activated receptors (PPARs) govern epidermal lipid synthesis and metabolism. In skin, PPAR activation has been shown to regulate genes responsible for permeability barrier homeostasis, epidermal differentiation, lipid biosynthesis, and inflammation.

Objective

Given the known dermatologic benefits of PPARs, we set out to discover a naturally derived, multi-molecule complex that would be superior to the more commonly formulated conjugated linoleic acids (CLAs). We hypothesized that a complex may be capable of modulating PPAR-α by cooperative or multi-ligand binding interactions to accelerate skin barrier repair.

Methods

To achieve this, we assembled a novel PPAR-α agonist complex, referred to as RFV3, from a combination of small molecules routinely used in Ayurvedic medicine and accepted in cosmetic and topical over-the-counter dermatologic products. We tested RFV3’s potential as a PPAR-α agonist by evaluating its transcriptional response, ligand binding affinity to PPAR-α, gene expression profiles and barrier repair properties in human skin explant models.

Results

We assembled RFV3 by solubilizing two standardized plant extracts in a suitable solvent and induced a significant transcriptional response in PPAR-α luciferase reporter assay. Furthermore, transcriptome profiling of RFV3-treated epidermal substitutes revealed expressed genes consistent with known targets of PPAR-α, including those involved in epidermal barrier repair. In addition, in silico modeling demonstrated differential co-binding affinities of RFV3 to PPAR-α compared with those of the endogenous ligands (CLAs) and a synthetic PPAR-α agonist. Lastly, delipidated skin explant models confirmed accelerated barrier repair activity with significant increases in ceramides, filaggrin and transglutaminase-1 after treatment.

Conclusion

These findings suggest that the RFV3 complex successfully mimics a PPAR-α agonist and induces synthesis of skin barrier lipids and proteins consistent with known PPAR pathways.

Revealing the Correlation between Altered Skin Lipids Composition and Skin Disorders

Human skin layers serve as a barrier between the body and the environment, by preventing water loss and blocking the entry of chemicals, allergens, and microbes. Recent data showed that skin lipids are vital ‘key players’ of several functions and mechanisms performing in the skin, such as, barrier function and microbiome composition. Abnormalities in lipid composition have been observed in inflammatory cutaneous diseases with a disrupted skin barrier. This review aims to demonstrate the fundamental role of keratinocytes, sebocytes, and microbiome-derived lipids in the maintenance of the skin barrier. Furthermore, it would reveal the correlation between altered skin lipids’ composition, microbiome, and the occurrence of certain dermatological disorders such as acne vulgaris, atopic dermatitis, psoriasis, and rosacea.

Peroxisomal Fatty Acid Oxidation and Glycolysis Are Triggered in Mouse Models of Lesional Atopic Dermatitis

Alterations of the lipid profile of the stratum corneum have an important role in the pathogenesis of atopic dermatitis (AD) because they contribute to epidermal barrier impairment. However, they have not previously been envisioned as a cellular response to altered metabolic requirements in AD epidermis. In this study, we report that the lipid composition in the epidermis of flaky tail, that is, ft/ft mice mimics that of human lesional AD (ADL) epidermis, both showing a shift toward shorter lipid species. The amounts of C24 and C26 free fatty acids and C24 and C26 ceramides-oxidized exclusively in peroxisomes-were reduced in the epidermis of ft/ft mice despite increased lipid synthesis, similar to that seen in human ADL edpidermis. Increased ACOX1 protein and activity in granular keratinocytes of ft/ft epidermis, altered lipid profile in human epidermal equivalents overexpressing ACOX1, and increased ACOX1 immunostaining in skin biopsies from patients with ADL suggest that peroxisomal β-oxidation significantly contributes to lipid signature in ADL epidermis. Moreover, we show that increased anaerobic glycolysis in ft/ft mouse epidermis is essential for keratinocyte proliferation and adenosine triphosphate synthesis but does not contribute to local inflammation. Thus, this work evidenced a metabolic shift toward enhanced peroxisomal β-oxidation and anaerobic glycolysis in ADL epidermis.

Cannabidiol Application Increases Cutaneous Aquaporin-3 and Exerts a Skin Moisturizing Effect

Cannabidiol (CBD) is a major nonpsychotropic component of Cannabis sativa with various pharmacological activities. In this study, we investigated the skin moisturizing effect of CBD and its mechanism. A 1% CBD solution was applied daily to skin of HR-1 hairless (Seven-week-old, male) for 14 days. The dermal water content in CBD-treated mice was significantly increased compared to that in the control group. Furthermore, no inflammatory reaction in the skin and no obvious skin disorders were observed. The mRNA expression levels of loricrin, filaggrin, collagen, hyaluronic acid degrading enzyme, hyaluronic acid synthase, ceramide degrading enzyme, and ceramide synthase in the skin were not affected by the application of CBD. However, only aquaporin-3 (AQP3), a member of the aquaporin family, showed significantly higher levels in the CBD-treated group than in the control group at both the mRNA and protein levels. It was revealed that CBD has a moisturizing effect on the skin. In addition, it is possible that increased expression of AQP3, which plays an important role in skin water retention, is a contributor to the mechanism. CBD is expected to be developed in the future as a cosmetic material with a unique mechanism.

Changes in Phospholipid/Ceramide Profiles and Eicosanoid Levels in the Plasma of Rats Irradiated with UV Rays and Treated Topically with Cannabidiol

Chronic UV radiation causes oxidative stress and inflammation of skin and blood cells. Therefore, in this study, we assessed the effects of cannabidiol (CBD), a natural phytocannabinoid with antioxidant and anti-inflammatory properties, on the phospholipid (PL) and ceramide (CER) profiles in the plasma of nude rats irradiated with UVA/UVB and treated topically with CBD. The results obtained showed that UVA/UVB radiation increased the levels of phosphatidylcholines, lysophospholipids, and eicosanoids (PGE2, TxB2), while downregulation of sphingomyelins led to an increase in CER[NS] and CER[NDS]. Topical application of CBD to the skin of control rats significantly upregulated plasma ether-linked phosphatidylethanolamines (PEo) and ceramides. However, CBD administered to rats irradiated with UVA/UVB promoted further upregulation of CER and PEo and led to significant downregulation of lysophospholipids. This was accompanied by the anti-inflammatory effect of CBD, manifested by a reduction in the levels of proinflammatory PGE2 and TxB2 and a dramatic increase in the level of anti-inflammatory LPXA4. It can therefore be suggested that topical application of CBD to the skin of rats exposed to UVA/UVB radiation prevents changes in plasma phospholipid profile resulting in a reduction of inflammation by reducing the level of LPE and LPC species and increasing antioxidant capacity due to upregulation of PEo species.

Enhanced phenotype of calcipotriol-induced atopic dermatitis in filaggrin-deficient mice

Impaired function of filaggrin (FLG) is a major predisposing factor for atopic dermatitis (AD). Several studies on FLG-deficient (Flg^-/- ) mice have indicated an essential role for FLG in the skin barrier and the development of AD, but none of the studies have described the characteristics on Flg^-/- mice with calcipotriol (CPT)-induced atopic dermatitis, which restricts the comprehensive understanding of functions of FLG. The present study sought to generate Flg^-/- mice and applied CPT to produce AD-like dermatitis for in vivo analysis of the FLG functions. CPT was applied on the skin of Flg^-/- mice to establish the AD-like dermatitis mouse model. The lesion inflammation was evaluated by gross ear thickness, histopathology, immunofluorescence, and cytokine production. Also, mucopolysaccharide polysulfate (MPS) and ceramide were used to observe the therapeutic function in this model. The results showed that the inflammation of CPT-induced dermatitis in Flg^-/- mice was more severer than that of wild-type (WT) mice, as evident by the increased level of gross appearance, ear thickness, inflammatory cell infiltration (mast cells and CD3⁺ T cells), and inflammatory cytokine expression (interleukin (IL)-4, IL-6, IL-13, and thymic stromal lymphopoietin (TSLP)). The emollients MPS and ceramide partially restored the epidermal function and alleviated the skin inflammation in Flg^-/- mice with CPT-induced AD-like dermatitis. The current study demonstrated that skin barrier protein FLG is critical in the pathogenesis of AD. Also, the AD mouse model induced by CPT in Flg^-/- mice could be utilized to search for drug targets in AD.

The human vermilion surface contains a rich amount of cholesterol sulfate than the skin

BACKGROUND

The vermilion of the human lip presents characteristic features and undergoes aging faster than the skin. Therefore, knowledge of the vermilion surface-specific functional molecules is important to understand lip aging and formulate lip care products. Previously, we analyzed the free fatty acids distributions and showed that docosahexaenoic acid highly accumulated in the vermilion's epithelium than in the skin.

OBJECTIVE

We aimed to explore the functional molecules other than the free fatty acids on the vermilion's surface.

METHODS

Human lip tissues from children and tape-stripped samples from smooth and rough lips of adults were measured by desorption electrospray ionization-mass spectrometry imaging (DESI-MSI).

RESULTS

DESI-MSI of children's lip sections revealed a major distribution of five phospholipid species in the viable layer, but not in the superficial area, of both the vermilion and the skin than that in the underlying tissue. Interestingly, a remarkably higher distribution of cholesterol sulfate was observed in the vermilion's superficial area compared to that in the skin in all subjects under this study. Furthermore, theDESI-MSI of tape-stripped lip sample showed an overall higher accumulation of cholesterol sulfate in the stratum corneum of the rough lip than that in the smooth lips showed an overall higher accumulation of cholesterol sulfate in the stratum corneum of the rough lips than that in the smooth lips.

CONCLUSION

Our study concluded that cholesterol sulfate has a characteristic distribution to the vermilion's surface and showed an association with the roughness of the lip.

PPARdelta in Affected Atopic Dermatitis and Psoriasis: A Possible Role in Metabolic Reprograming

Peroxisome proliferator-activated receptors (PPARs) are nuclear hormone receptors expressed in the skin. Three PPAR isotypes, α (NRC1C1), β or δ (NRC1C2) and γ (NRC1C3), have been identified. After activation through ligand binding, PPARs heterodimerize with the 9-cis-retinoic acid receptor (RXR), another nuclear hormone receptor, to bind to specific PPAR-responsive elements in regulatory regions of target genes mainly involved in organogenesis, cell proliferation, cell differentiation, inflammation and metabolism of lipids or carbohydrates. Endogenous PPAR ligands are fatty acids and fatty acid metabolites. In past years, much emphasis has been given to PPARα and γ in skin diseases. PPARβ/δ is the least studied PPAR family member in the skin despite its key role in several important pathways regulating inflammation, keratinocyte proliferation and differentiation, metabolism and the oxidative stress response. This review focuses on the role of PPARβ/δ in keratinocytes and its involvement in psoriasis and atopic dermatitis. Moreover, the relevance of targeting PPARβ/δ to alleviate skin inflammation is discussed.

Co-delivery of methotrexate and nicotinamide by cerosomes for topical psoriasis treatment with enhanced efficacy

Psoriasis is an immune-mediated skin disorder that affects populations worldwide. Methotrexate (MTX) is a cytotoxic drug with powerful anti-proliferative and anti-inflammatory effects that has gained prominence in treating inflammatory diseases including psoriasis. However, low solubility and side effects through oral administration hinder its systemic application. In this study, we developed a novel niosomes based on ceramide (cerosomes) to co-deliver MTX and nicotinamide (NIC), i.e., MTX/NIC cerosomes, for topically treating psoriasis with the aim to enhancing the efficacy and reducing the toxicity. NIC significantly solublized MTX by forming hydrogen bonds with MTX. In vitro and in vivo permeation studies showed that the cerosomes significantly promoted drug permeation through and retention in the skin, and the enhancing mechanism was clarified by Fourier transform infraredand Raman spectroscopy. MTX/NIC cerosomes exhibited strong anti-proliferation effect on lipopolysaccharide- irritated HaCaT cells by arresting the cell cycle at S phase and inducing apoptosis. Importantly, compared to MTX oral administration, topical application of MTX/NIC cerosomes on imiquimod (IMQ)-induced psoriatic mouse model exhibited a superior performance in ameliorating skin lesions, reducing spleen index and epidermal thickness, and downregulating the mRNA expression levels of proinflammatory cytokines including TNFα, IL-23, IL-17A, IL-6, IL-1β, and IL-22. Taken together, MTX/NIC cerosomes is a promising approach for psoriasis topical treatment.