Biosignatures of defective sebaceous gland activity in sebum-rich and sebum-poor skin areas in adult atopic dermatitis.

Atopic dermatitis (AD) is a composite disease presenting disruption of the skin permeability barrier (SPB) in the stratum corneum (SC). Recent evidence supports derangement of the sebaceous gland (SG) activity in the AD pathomechanisms. The objective of this study was to delineate profiles of both sebaceous and epidermal lipids and of aminoacids from SG-rich (SGR) and SG-poor (SGP) areas in AD. Both sebum and SC were sampled from SGR areas, while SC was sampled also from SGP areas in 54 adult patients with AD, consisting of 34 and 20 subjects, respectively with and without clinical involvement of face, and in 44 age and sex-matched controls. Skin biophysics were assessed in all sampling sites. Disruption of the SBP was found to be associated with dysregulated lipidome. Abundance of sapienate and lignocerate, representing, respectively, sebum and the SC type lipids, were decreased in sebum and SC from both SGR and SGP areas. Analogously, squalene was significantly diminished in AD, regardless the site. Extent of lipid derangement in SGR areas was correlated with the AD severity. The abundance of aminoacids in the SC from SGR areas was altered more than that determined in SGP areas. Several gender-related differences were found in both controls and AD subgroups. In conclusion, the SG activity was differently compromised in adult females and males with AD, in both SGR and SGP areas. In AD, alterations in the aminoacidome profiles were apparent in the SGR areas. Lipid signatures in association with aminoacidome and skin physical properties may serve the definition of phenotype clusters that associate with AD severity and gender.

Comparative Characterization of Human Meibomian Glands, Free Sebaceous Glands, and Hair-Associated Sebaceous Glands Based on Biomarkers, Analysis of Secretion Composition, and Gland Morphology.

Meibomian gland dysfunction (MGD) is one of the main causes of dry eye disease. To better understand the physiological functions of human meibomian glands (MGs), the present study compared MGs with free sebaceous glands (SGs) and hair-associated SGs of humans using morphological, immunohistochemical, and liquid chromatography-mass spectrometry (LCMS)-based lipidomic approaches. Eyelids with MGs, nostrils, lips, and external auditory canals with free SGs, and scalp with hair-associated SGs of body donors were probed with antibodies against cytokeratins (CK) 1, 8, 10, and 14, stem cell markers keratin 15 and N-cadherin, cell-cell contact markers desmoglein 1 (Dsg1), desmocollin 3 (Dsc3), desmoplakin (Dp), plakoglobin (Pg), and E-cadherin, and the tight junction protein claudin 5. In addition, Oil Red O staining (ORO) was performed in cryosections. Secretions of MGs as well as of SGs of nostrils, external auditory canals, and scalps were collected from healthy volunteers, analyzed by LCMS, and the data were processed using various multivariate statistical analysis approaches. Serial sections of MGs, free SGs, and hair-associated SGs were 3D reconstructed and compared. CK1 was expressed differently in hair-associated SGs than in MGs and other free SGs. The expression levels of CK8, CK10, and CK14 in MGs were different from those in hair-associated SGs and other free SGs. KRT15 was expressed differently in hair-associated SGs, whereas N-cadherin was expressed equally in all types of glands. The cell-cell contact markers Dsg1, Dp, Dsc3, Pg, and E-cadherin revealed no differences. ORO staining showed that lipids in MGs were more highly dispersed and had larger lipid droplets than lipids in other free SGs. Hair-associated SGs had a smaller number of lipid droplets. LCMS revealed that the lipid composition of meibum was distinctively different from that of the sebum of the nostrils, external auditory canals, and scalp. The 3D reconstructions of the different glands revealed different morphologies of the SGs compared with MGs which are by far the largest type of glands. In humans, MGs differ in their morphology and secretory composition and show major differences from free and hair-associated SGs. The composition of meibum differs significantly from that of sebum from free SGs and from hair-associated SGs. Therefore, the MG can be considered as a highly specialized type of holocrine gland that exhibits all the histological characteristics of SGs, but is significantly different from them in terms of morphology and lipid composition.

Spatial transcriptomics reveals altered lipid metabolism and inflammation-related gene expression of sebaceous glands in psoriasis and atopic dermatitis.

Sebaceous glands drive acne, however, their role in other inflammatory skin diseases remains unclear. To shed light on their potential contribution to disease development, we investigated the spatial transcriptome of sebaceous glands in psoriasis and atopic dermatitis patients across lesional and non-lesional human skin samples. Both atopic dermatitis and psoriasis sebaceous glands expressed genes encoding key proteins for lipid metabolism and transport such as ALOX15B, APOC1, FABP7, FADS1/2, FASN, PPARG, and RARRES1. Also, inflammation-related SAA1 was identified as a common spatially variable gene. In atopic dermatitis, genes mainly related to lipid metabolism (e.g. ACAD8, FADS6, or EBP) as well as disease-specific genes, i.e., Th2 inflammation-related lipid-regulating HSD3B1 were differentially expressed. On the contrary, in psoriasis, more inflammation-related spatially variable genes (e.g. SERPINF1, FKBP5, IFIT1/3, DDX58) were identified. Other psoriasis-specific enriched pathways included lipid metabolism (e.g. ACOT4, S1PR3), keratinization (e.g. LCE5A, KRT5/7/16), neutrophil degranulation, and antimicrobial peptides (e.g. LTF, DEFB4A, S100A7-9). In conclusion, our results show that sebaceous glands contribute to skin homeostasis with a cell type-specific lipid metabolism, which is influenced by the inflammatory microenvironment. These findings further support that sebaceous glands are not bystanders in inflammatory skin diseases, but can actively and differentially modulate inflammation in a disease-specific manner.

Alcohol Promotes Lipogenesis in Sebocytes-Implications for Acne.

The oral consumption of alcohol (ethanol) has a long tradition in humans and is an integral part of many cultures. The causal relationship between ethanol consumption and numerous diseases is well known. In addition to the well-described harmful effects on the liver and pancreas, there is also evidence that ethanol abuse triggers pathological skin conditions, including acne. In the present study, we addressed this issue by investigating the effect of ethanol on the energy metabolism in human SZ95 sebocytes, with particular focus on qualitative and quantitative lipogenesis. It was found that ethanol is a strong trigger for lipogenesis, with moderate effects on cell proliferation and toxicity. We identified the non-oxidative metabolism of ethanol, which produced fatty acid ethyl esters (FAEEs), as relevant for the lipogenic effect-the oxidative metabolism of ethanol does not contribute to lipogenesis. Correspondingly, using the Seahorse extracellular flux analyzer, we found an inhibition of the mitochondrial oxygen consumption rate as a measure of mitochondrial ATP production by ethanol. The ATP production rate from glycolysis was not affected. These data corroborate that ethanol-induced lipogenesis is independent from oxygen. In sum, our results give a causal explanation for the prevalence of acne in heavy drinkers, confirming that alcoholism should be considered as a systemic disease. Moreover, the identification of key factors driving ethanol-dependent lipogenesis may also be relevant in the treatment of acne vulgaris.

High incidence of sebaceous gland inflammation in aldose reductase-deficient mice.

Aldose reductase is a member of the 1B1 subfamily of aldo-keto reductase gene superfamily. The action of aldose reductase (AR) has been implicated in the pathogenesis of a variety of disease states, most notably complications of diabetes mellitus including neuropathy, retinopathy, nephropathy, and cataracts. To explore for mechanistic roles for AR in disease pathogenesis, we established mutant strains produced using Crispr-Cas9 to inactivate the AKR1B3 gene in C57BL6 mice. Phenotyping AR-knock out (ARKO) strains confirmed previous reports of reduced accumulation of tissue sorbitol levels. Lens epithelial cells in ARKO mice showed markedly reduced epithelial-to-mesenchymal transition following lens extraction in a surgical model of cataract and posterior capsule opacification. A previously unreported phenotype of preputial sebaceous gland swelling was observed frequently in male ARKO mice homozygous for the mutant AKR1B3 allele. This condition, which was shown to be accompanied by infiltration of proinflammatory CD3+ lymphocytes, was not observed in WT mice or mice heterozygous for the mutant allele. Despite this condition, reproductive fitness of the ARKO strain was indistinguishable from WT mice housed under identical conditions. These studies establish the utility of a new strain of AKR1B3-null mice created to support mechanistic studies of cataract and diabetic eye disease.

Skin single-cell transcriptomics reveals a core of sebaceous gland-relevant genes shared by mice and humans.

BACKGROUND: Single-cell RNA sequencing (scRNA-seq) has been widely applied to dissect cellular heterogeneity in normal and diseased skin. Sebaceous glands, essential skin components with established functions in maintaining skin integrity and emerging roles in systemic energy metabolism, have been largely neglected in scRNA-seq studies. METHODS: Departing from mouse and human skin scRNA-seq datasets, we identified gene sets expressed especially in sebaceous glands with the open-source R-package oposSOM. RESULTS: The identified gene sets included sebaceous gland-typical genes as Scd3, Mgst1, Cidea, Awat2 and KRT7. Surprisingly, however, there was not a single overlap among the 100 highest, exclusively in sebaceous glands expressed transcripts in mouse and human samples. Notably, both species share a common core of only 25 transcripts, including mitochondrial and peroxisomal genes involved in fatty acid, amino acid, and glucose processing, thus highlighting the intense metabolic rate of this gland. CONCLUSIONS: This study highlights intrinsic differences in sebaceous lipid synthesis between mice and humans, and indicates an important role for peroxisomal processes in this context. Our data also provides attractive starting points for experimentally addressing novel candidates regulating sebaceous gland homeostasis.

Sebaceous carcinoma with apocrine differentiation arising in a known case of basal cell carcinoma: A rare entity.

Sebaceous carcinoma is a ra malignant tumor of adnexal origin arising from sebaceous glands. It is most commonly seen arising from the eyelids and head and neck. It is predominantly seen in females with an average age of around 65 years. Apocrine differentiation in sebaceous carcinomas is rare but has been reported in the literature. Here, we present a case of sebaceous carcinoma with apocrine differentiation in a 62-year- old female who was a diagnosed case of basal cell carinoma.

Extra-ocular sebaceous carcinoma - A rare case report.

Sebaceous gland carcinoma is a rare and aggressive skin cancer derived from the sebaceous glands. Sebaceous carcinomas are divided into those occurring in ocular (75%) and extra-ocular locations. A 45-year-old female patient presented with rapidly growing swelling over the upper back region. It was provisionally diagnosed as an infected sebaceous cyst, and an excision biopsy was received in the pathology department. Histopathology was reported as sebaceous carcinoma, Grade II, Stage P T3 Nx. Immunohistochemistry was positive for epithelial membrane antigen. Sebaceous carcinoma accounts for 0.2-4.6% of all malignant cutaneous neoplasms, and the estimated rate of occurrence is only 1-2 per 1 million individuals per year. These tumors frequently present with a painless sub-cutaneous nodule, but they can also present as pedunculated lesions, irregular mass, or diffuse thickening of the skin. Hence, they are misinterpreted as other benign tumors or inflammatory conditions, thereby leading to delay in diagnosis, inappropriate treatment, increased morbidity, and mortality.

1726 nm Lasers for the Treatment of Acne Vulgaris.

The treatment of acne vulgaris traditionally consists of a combination of topical and oral medications. The use of lasers to treat this condition has been an area of increasing research, and several types have previously been used in the treatment of acne. New 1726 nm lasers specifically target the sebaceous gland, which is known to be pivotal in acne pathophysiology. This laser wavelength demonstrates substantial potential as a safe and effective therapeutic option for moderate to severe acne without the risks of systemic therapy. This paper reviews the 1726 nm lasers for acne vulgaris.

Evidence for the Clinical Association between Demodex and Rosacea: A Review.

BACKGROUND: Rosacea is a chronic inflammatory dermatological condition in humans, and its pathogenesis remains unclear. However, the development of rosacea is suspected to be related to Demodex, a microscopic commensal organism that resides in or near hair follicles and sebaceous glands. Although Demodex is known to be a host-specific, obligate commensal organism, it is currently difficult to be cultured in vitro to parasitize and infect other animal hosts. Therefore, direct evidence for a pathogenic role of Demodex in rosacea is currently lacking. SUMMARY: As circumstantial evidence, non-invasive skin-detecting techniques have shown abnormally elevated numbers of Demodex in rosacea patients. Increased cytokine levels such as IL-10, IL-8, and IL-12p70 have been observed in human sebocytes following the Demodex challenge, and acaricides have been found to be effective in rosacea therapy, all point to a close relationship between Demodex and rosacea. Based on these findings, we conducted a comprehensive literature review to summarize the current state of knowledge, research insights, and clinical treatment recommendations for Demodex-associated rosacea, with the ultimate goal of improving patient outcomes.

Selective photothermolysis in acne treatment: The impact of laser power.

BACKGROUND: Selective photothermolysis (SPT) using a 1726 nm laser has emerged as a safe and effective treatment option for acne vulgaris by targeting sebaceous glands (SG). Power output plays a crucial role in determining treatment selectivity and efficacy. AIMS: This work highlights the advantages of a higher-power laser source and outlines the limitations of lower-power laser sources and the subsequent impact on treatment. METHODS: Light transport and bioheat transfer simulations were performed to demonstrate photothermal impact on the SG and the surrounding dermis when irradiated by a high- or lower-power laser source. RESULTS: The simulations showed that a single higher-power-shorter-pulse (HPSP) selectively increases SG temperature well beyond bulk temperatures, which is desirable for SPT. Selectivity decreases linearly with power for the single lower-power-longer-pulses (LPLP) exposure. A multiple-LPLP approach elevates bulk temperatures significantly more than a single-pulse strategy, compromising selectivity. CONCLUSION: The goal of SPT is to damage SG safely and effectively by creating an intense temperature rise localized to the SG while moderately increasing the dermis temperature. This goal is mostly achieved with higher-power lasers that deliver a single HPSP. Lower-power lasers, longer pulse widths, and multi-pulse strategies result in higher bulk temperatures and lower SG selectivity, making such treatment challenging to execute while adding a higher risk of discomfort and downtime.

A new easy technique to identify the correct artificial hair implantation site: A case series and preliminary results.

BACKGROUND: The implantation of artificial hair is a successful standardized procedure to restore bald areas or scarred alopecic surfaces of the scalp in both sexes. MATERIALS AND METHODS: Sebometric measurements were taken, pre, 1, 3, and 6 months postimplant in two symmetric frontotemporal areas of the scalp of seven volunteers to be implanted with 50 units of artificial hair. The artificial hair used in this study are Biofibre 4.0 produced by Medicap srl, Italy. RESULTS: The dermaroller assisted procedure was performed only on one side, and the plain random implant contralaterally for comparison. A marked downregulation of the sebum concentration was observed in the dermaroller treated area 1, 3, and 6 months later in respect to the control side. CONCLUSION: The dermaroller assisted procedure is safe and effective in reducing the foreign body reaction by the sebaceous glands and the vascular axis injured by the implanting needle; a longer standing success of the implanted hair can thus be achieved reducing the burden of inflammatory reaction.

The primary role of sebum in the pathophysiology of acne vulgaris and its therapeutic relevance in acne management.

BACKGROUND: Sebum physiology and its contributions to acne vulgaris (AV) pathophysiology have been long debated. Within the pilosebaceous unit, androgens drive sebocyte production of sebum, comprising mono-, di-, and triglycerides (the latter converted to fatty acids); squalene; cholesterol; cholesterol esters; and wax esters. Upon release to the skin surface, human sebum has important roles in epidermal water retention, antimicrobial defenses, and innate immune responses. AIMS: Alterations in sebum alone and with other pathogenic factors (inflammation, follicular hyperkeratinization, and Cutibacterium acnes [C. acnes] proliferation) contribute to AV pathophysiology. Androgen-driven sebum production, mandatory for AV development, propagates C. acnes proliferation and upregulates inflammatory and comedogenic cascades. RESULTS: Some sebum lipids have comedogenic effects in isolation, and sebum content alterations (including elevations in specific fatty acids) contribute to AV pathogenesis. Regional differences in facial sebum production, coupled with patient characteristics (including sex and age), help exemplify this link between sebum alterations and AV lesion formation. CONCLUSIONS: To date, only combined oral contraceptives and oral spironolactone (both limited to female patients), oral isotretinoin and topical clascoterone (cortexolone 17α-propionate) modulate sebum production in patients with AV. A better understanding of mechanisms underlying sebaceous gland changes driving AV development is needed to expand the AV treatment armamentarium.

Emodin exhibits anti-acne potential by inhibiting cell growth, lipogenesis, and inflammation in human SZ95 sebocytes.

Emodin, a natural anthraquinone derivative, possesses anti-proliferative and anti-inflammatory properties in skin diseases. However, little information is available on the efficacy of emodin in treating acne vulgaris (acne). This study aims to investigate the protective effects and potential mechanisms of emodin as an anti-acne agent. In vitro, SZ95 sebocytes was chose to establish an acneigenic cellular model. We found that emodin effectively inhibited proliferation, induced cell cycle arrest and apoptosis of SZ95 sebocytes in a dose-dependent manner. To evaluate the lipid-lowering potential of emodin, we examined the levels of lipid contents and lipogenic transcription factors, and found that both lipid production and protein expression of PPARγ, LXR α/ß, and SREBP-1 were decreased after treatment with emodin. Furthermore, our results revealed that emodin inhibited sebaceous lipogenesis induced by insulin-like growth factor 1 (IGF-1), which was accompanied by a potent inhibition of the phosphoinositide-3-kinase (PI3K)/Akt/forkhead box protein O1 (FoxO1) pathway. In detail, emodin augmented the inhibitory effect of isotretinoin and PI3K inhibitor LY294002, while attenuating the activation of IGF-1 on PI3K/Akt/FoxO1 pathway. In addition, emodin could decrease the secretion of pro-inflammatory cytokines IL-6 and IL-8, and suppress the expression of NLRP3, capase-1, IL-1ß, and IL-18 in SZ95 sebocytes exposed to Cutibacterium acnes. Overall, our study provides preliminary evidence supporting the anti-growth, anti-lipogenic and anti-inflammatory properties of emodin, indicating the potential therapeutic application of emodin for acne treatment.

Ophthalmic Manifestations of Seborrheic Dermatitis.

Seborrheic dermatitis (SD) is a common, chronic inflammatory skin disease that affects the sebaceous tissues of the body. The meibomian glands of the eyelids are modified sebaceous glands. Involvement of the meibomian glands and their dysfunctioning are significant in SD; however, the ophthalmic features of SD have been poorly described in the literature. The ophthalmic manifestations of SD and the significance of ocular examinations in SD patients are discussed in this review.

Evaluation of the effect of botulinum toxin injection in aggravating or improving seborrheic dermatitis symptoms: A prospective, single-arm clinical trial.

INTRODUCTION: Considering the proven therapeutic effect of botulinum toxin and the pathophysiology of seborrheic dermatitis, conflicting hypotheses have been put forward regarding the effect of injection of this toxin on the improvement or exacerbation of seborrheic dermatitis. Because of the lack of consistent studies investigating this relationship, we decided to conduct this study to investigate the effect of local botulinum toxin injection on sebum production and improvement or worsening of seborrheic dermatitis lesions. METHOD: This study was a prospective, single-arm clinical trial that involved the injection of botulinum toxin into 20 patients with complaints of skin wrinkles and simultaneous symptoms of seborrheic dermatitis. The trial was conducted at a dermatology clinic between March 2019 and March 2021. Two important characteristics of these patients were seborrheic dermatitis on the face or scalp and a referral for botulinum toxin injection to remove facial wrinkles. The Seborrheic Dermatitis Area and Severity Index (SDASI) was used to determine the severity of symptoms. RESULTS: In study of 20 patients with an average age of 40 years, despite the decrease in the average scores of all examined criteria of seborrheic dermatitis symptoms in study, 1 month after botulinum toxin injection, no significant effect of using this toxin was seen on the improvement of patients' symptoms (p value >0.05). CONCLUSION: Despite the emphasis of many studies on the effectiveness of botulinum toxin in reducing the activity of sebaceous glands, the use of botulinum toxin as a therapeutic modality for control the symptoms of seborrheic dermatitis is not suggested by this study. Conducting studies in which the location and technique of injection and the follow-up intervals of patients in them are based on the standard of other studies, are the suggestions made by comparing the results and method of the current study with other studies.

Spindle Cell-Predominant Trichodiscoma With Palisading Arrangement: A Rare Variant.

ABSTRACT: Spindle cell-predominant trichodiscoma (SCPT) is a benign adnexal neoplasm, best categorized within the trichodiscoma-fibrofolliculoma continuum. SCPTs clinically present as dome-shaped papules usually on the face, particularly on the nose or the nasolabial fold. The SCPT variant has been described as a particularly cellular trichodiscoma composed of small interweaving fascicles and sheets of spindle cells. Identical lesions were previously referred to as neurofollicular hamartomas because of their predominantly fascicular stromal cellularity and focal S100 positivity. In this article, we report a rare variant of SCPT with a palisaded arrangement. The patient is a middle-aged man with no significant dermatologic history who presented with a skin-colored papule on the left nasal ala. It had been present for approximately 10 years with only minimal growth over that time. A biopsy was obtained. Histopathological analysis revealed a dermal papule composed of bland spindle cells arranged in a striking palisading pattern within a fibromyxoid stroma with associated peripheral hyperplasia of sebaceous glands. The palisaded pattern shared features reminiscent of Verocay bodies of a schwannoma. Immunohistochemical studies revealed stromal spindled cells with a strong and diffuse pattern of CD34 expression and absent S100 and SOX10 expressions. To our knowledge, only 2 cases of SCPT with a palisaded pattern have been presented. SCPT with a palisaded pattern is a rare histopathologic variant that may resemble a schwannoma but can be recognized by its strong epithelial components and immunohistochemical staining pattern.