Understanding innate immunity and inflammation in acne: implications for management

Very low-calorie ketogenic diet (VLCKD): a therapeutic nutritional tool for acne?

BACKGROUND

Acne, a chronic inflammatory disease impacting the pilosebaceous unit, is influenced significantly by inflammation and oxidative stress, and is commonly associated with obesity. Similarly, obesity is also associated with increased inflammation and oxidation. The role of diet in acne remains inconclusive, but the very low-calorie ketogenic diet (VLCKD), known for weight loss and generating anti-inflammatory ketone bodies, presents promising potential. Despite this, the effects of VLCKD on acne remain underexplored. This study aimed to investigate the efficacy of a 45-day active phase of VLCKD in reducing the clinical severity of acne in young women with treatment-naïve moderate acne and grade I obesity.

METHODS

Thirty-one women with treatment-naïve moderate acne, grade I obesity (BMI 30.03-34.65 kg/m2), aged 18-30 years, meeting inclusion/exclusion criteria, and consenting to adhere to VLCKD were recruited. Baseline and post-intervention assessments included anthropometric measurements, body composition, phase angle (PhA), trimethylamine N-oxide (TMAO) levels, and reactive oxygen metabolite derivatives (dROMs) as markers of inflammation, dysbiosis, and oxidative stress, respectively. A comprehensive dermatological examination, incorporating the Global Acne Grading System (GAGS) and the Dermatology Life Quality Index (DLQI), was conducted for all women.

RESULTS

VLCKD resulted in general improvements in anthropometric and body composition parameters. Significantly, there were significant reductions in both the GAGS score (Δ%: - 31.46 ± 9.53, p < 0.001) and the DLQI score (Δ%: - 45.44 ± 24.02, p < 0.001) after the intervention. These improvements coincided with significant decreases in TMAO (p < 0.001) and dROMs (p < 0.001) levels and a significant increase in PhA (Δ%: + 8.60 ± 7.40, p < 0.001). Changes in the GAGS score positively correlated with changes in dROMs (p < 0.001) and negatively with PhA (p < 0.001) even after adjusting for Δ% FM. Changes in the DLQI score positively correlated with changes in dROMs (p < 0.001) and negatively with PhA (p < 0.001) even after adjustment for Δ% FM.

CONCLUSION

Given the side effects of drugs used for acne, there is an increasing need for safe, tolerable, and low-cost treatments that can be used for acne disease. The 45-day active phase of VLCKD demonstrated notable improvements in acne severity, and these improvements seemed to be attributable to the known antioxidant and anti-inflammatory effects of VLCKD.

Macrophages in acne vulgaris: mediating phagocytosis, inflammation, scar formation, and therapeutic implications

Macrophages serve as a pivotal nexus in the pathogenesis of acne vulgaris, orchestrating both the elimination of Cutibacterium acnes (C. acnes) and lipid metabolic regulation while also possessing the capacity to exacerbate inflammation and induce cutaneous scarring. Additionally, recent investigations underscore the therapeutic potential inherent in macrophage modulation and challenge current anti-inflammatory strategies for acne vulgaris. This review distills contemporary advances, specifically examining the dual roles of macrophages, underlying regulatory frameworks, and emergent therapeutic avenues. Such nuanced insights hold the promise of guiding future explorations into the molecular etiology of acne and the development of more efficacious treatment modalities.

Association of different cell types and inflammation in early acne vulgaris

Acne vulgaris, one of the most common skin diseases, is a chronic cutaneous inflammation of the upper pilosebaceous unit (PSU) with complex pathogenesis. Inflammation plays a central role in the pathogenesis of acne vulgaris. During the inflammatory process, the innate and adaptive immune systems are coordinately activated to induce immune responses. Understanding the infiltration and cytokine secretion of differential cells in acne lesions, especially in the early stages of inflammation, will provide an insight into the pathogenesis of acne. The purpose of this review is to synthesize the association of different cell types with inflammation in early acne vulgaris and provide a comprehensive understanding of skin inflammation and immune responses.

Formulation and Evaluation of Herbal-Based Antiacne Gel Preparations

Acne vulgaris is an inflammatory skin condition that affects virtually everyone at some point. Papules, comedones, pustules, scarring, and nodules are standard features of the disease and can have a detrimental social and psychological impact on an individual. Although allopathic acne treatments are available, they have adverse side effects, are expensive, and are prone to cause antibiotic resistance. The present study is aimed at formulating and evaluating topical gels containing Aloe vera, Allium cepa, and Eucalyptus globulus extracts as potential antiacne drugs. Six formulations containing the herbal extracts were prepared using 1% Carbopol 940 as a gelling agent. The phytochemical composition of the plant extracts was determined. The extracts and gels' minimum inhibitory concentration (MIC) was assessed using the microbroth dilution method. The physicochemical properties of the formulated gels, such as homogeneity, colour, texture, odour, grittiness, spreadability, extrudability, viscosity, pH, and drug content, were evaluated. All the plant extracts contained alkaloids, flavonoids, tannins, triterpenoids, and coumarins. The gel formulations showed varying activity against Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, Candida albicans, and Pseudomonas aeruginosa at various concentrations. The phytochemical components of the plant extracts are probably responsible for the antimicrobial activity of the gel formulations. The 5% Aloe vera-Allium cepa (1 : 1) combination gel formulation showed excellent activity against Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans, with MICs of 12.50, 25.00, 6.25, 25.00, and 12.50 mg/mL, respectively. The gels generally had good physicochemical and antimicrobial properties and could be used as antiacne remedies.

A review of skin immune processes in acne

Acne vulgaris is one of the most prevalent skin conditions, affecting almost all teenagers worldwide. Multiple factors, including the excessive production of sebum, dysbiosis of the skin microbiome, disruption of keratinization within hair follicles, and local inflammation, are believed to trigger or aggravate acne. Immune activity plays a crucial role in the pathogenesis of acne. Recent research has improved our understanding of the immunostimulatory functions of microorganisms, lipid mediators, and neuropeptides. Additionally, significant advances have been made in elucidating the intricate mechanisms through which cutaneous innate and adaptive immune cells perceive and transmit stimulatory signals and initiate immune responses. However, our understanding of precise temporal and spatial patterns of immune activity throughout various stages of acne development remains limited. This review provides a comprehensive overview of the current knowledge concerning the immune processes involved in the initiation and progression of acne. Furthermore, we highlight the significance of detailed spatiotemporal analyses, including analyses of temporal dynamics of immune cell populations as well as single-cell and spatial RNA sequencing, for the development of targeted therapeutic and prevention strategies.

Anti-IL-17A blockade did not significantly reduce inflammatory lesions in a placebo-controlled pilot study in adult patients with moderate to severe acne

BACKGROUND

CJM112 is a potent anti-IL-17A monoclonal antibody, whose clinical efficacy in psoriasis was recently documented. This study aimed to assess the effect of IL-17A blockade, using CJM112, in patients with moderate to severe acne.

METHODS

A randomized, placebo-controlled, double-blind, parallel-group, proof-of-concept study was conducted on patients with moderate to severe acne. Patients received CJM112 300 mg, 75 mg, or placebo subcutaneously during Treatment Period 1 (0-12 weeks). Patients receiving placebo were re-randomized to receive CJM112 300 mg or 75 mg during Treatment Period 2 (12-24 weeks). The primary endpoint was the number of inflammatory facial lesions at Week 12.

RESULTS

As the futility criterion was met during the interim analysis, only 52/75 (69.3%) patients were recruited. In total, 48/52 (92.3%) and 26/41 (63.4%) completed Treatment Periods 1 and 2, respectively. All groups exhibited a reduction in facial inflammatory lesions, with no difference observed between CJM112 and placebo (CJM112 300 mg 27.6 ± 20.7; CJM112 75 mg 30.4 ± 34.8; placebo 23.6 ± 13.6; primary endpoint). Additionally, no differences were observed between groups in other secondary and exploratory endpoints at Week 12.

CONCLUSIONS

Anti-IL-17A therapy was not significantly different compared to the placebo in reducing inflammatory lesions in patients with moderate to severe acne.

Integration of Single-Cell Transcriptomics Data Reveal Differences in Cell Composition and Communication in Acne

Purpose

Acne is a kind of hair follicle sebaceous inflammatory disease, which has a high incidence rate among adolescents. Comparative data on cells which beneficial for precise treatment of acne patients.

Patients and Methods

After integrating and removing the batch effect of single-cell transcriptomics data of acne patients and health skin, the dimensionality reduction clustering was performed and the change in characteristics of each cell group were analyzed. Further, cell communication differences between gender were analyzed by use Cellchat software.

Results

70,189 cells were analyzed, and 11 cell groups were identified. The proportion of basal cells and macrophages in skin of acne patients are relatively high than that of skin in healthy people. The results of cell communication showed that the communication intensity of acne patients was significantly higher than that of healthy skin, and the endothelial cells showed a strong ability to receive signals. From the perspective of gender differences, the proportion of macrophages in male patients were higher than that in female patients, and there were a large number of basal cells in the lesion area of female patients. There are also have some specific immune response ligand-receptor regulatory signals in male patients.

Conclusion

There are significant differences in skin cell composition and cell communication patterns between acne patients and healthy people, especially reflected in gender differences. Basal cells, macrophages and endothelial cells can serve as key targets for acne treatment. The treatment methods for men and women should be more personalized.

In vitro acne disease model from inertial focusing effect for studying the interactions between sebocyte glands and macrophages

Acne is one of the most widespread skin diseases. The acne mechanism is intricate, involving interactions between different types of cells (i.e., sebocytes and macrophages). One of the challenges in studying the mechanism of acne is that current in vitro culture methods cannot reflect the 3D cellular environment in the tissue, including inflammatory stimuli and cellular interactions especially the interactions between sebocytes and immune cells. To solve this issue, we generated an in vitro acne disease model consisting of 3D artificial sebocyte glands and macrophages through the inertial focusing effect method. Using this model, we produced a controllable inflammatory environment similar to the acne pathogenetic process in the skin. The 3D artificial sebocyte glands and macrophages can be separated for analyzing each cell type, assisting the in-depth understanding of the acne mechanism. This study indicates that proinflammatory macrophages promote lipid accumulation and induce oxidative stress in sebocyte glands. Additionally, in an inflammatory environment, sebocyte glands induce macrophage polarization into the M1 phenotype. Employing this model for drug screening, we also demonstrated that, cannabidiol (CBD), a clinically investigated drug, is effective in restoring lipid accumulation, oxidative stress, inflammatory cytokines and macrophage polarization in the acne disease.

1927nm fractional thulium fiber laser combined with 30% salicylic acid for the treatment of acne and acne scars: A prospective, randomized, and split-face study

OBJECTIVES

Patients with acne usually develops acne scars subsequently, early intervention of scars is crucial in acne management. 1927nm fractional thulium fiber laser (TFL) is effective in scars improvement and chemical peels with 30% supramolecular salicylic acid (SSA) can be applied for the treatment of acne. The purpose of this study is to evaluate and compare the efficacy and safety of TFL monotherapy versus the concomitant application of TFL and 30% SSA on acne and acne scars.

MATERIALS AND METHODS

Thirty-three patients with acne and acne scars were enrolled, and two sides of the face were randomly divided to receive either TFL and SSA chemical peeling or TFL. Four sessions of TFL treatments were applied with 4-week intervals for both sides, SSA combined treatment side received eight SSA chemical peels with 2-week intervals additionally. GAGS, ECCA score, the number of acne lesions, melanin index (MI) and erythema index (EI), transepidermal water loss (TEWL), and side effects were recorded at Weeks 0, 4, 8, 12, and 18. Satisfaction of patients was recorded on both sides at the end of the study.

RESULTS

Thirty patients completed the study. Both control group (TFL monotherapy) and SSA group (TFL combined with SSA chemical peeling) significantly improved GAGS and ECCA score. SSA group showed higher efficacy in terms of GAGS and ECCA score, acne lesion count, TEWL, MI, EI, and satisfaction than control group. All the side effects were temporary and tolerable, no adverse effects were observed.

CONCLUSIONS

Both TFL and the TFL combined with 30% SSA chemical peeling are safe and effective for the treatment and prevention of acne and acne scars, though the combined group has higher efficacy.

Recent advances in understanding inflammatory acne: Deciphering the relationship between Cutibacterium acnes and Th17 inflammatory pathway

Acne vulgaris is a common chronic inflammatory skin disease of the pilosebaceous units. Four factors contribute to acne: hyperseborrhea and dysseborrhea, follicular hyperkeratinisation, skin microbiome dysbiosis and local immuno-inflammation. Recent key studies have highlighted a better understanding of the important role of Cutibacterium acnes (C. acnes) in the development of acne. Three major findings in the last decade include: (1) the ability of C. acnes to self-organize in a biofilm associated with a more virulent activity, (2) the loss of the C. acnes phylotype diversity and (3) the central role of the Th17 pathway in acne inflammation. Indeed, there is a close link between C. acnes and the activation of the Th17 immuno-inflammatory pathway at the initiation of acne development. These mechanisms are directly linked to the loss of C. acnes phylotype diversity during acne, with a predominance of the pro-pathogenic phylotype IA1. This specifically contributes to the induction of the Th17-mediated immuno-inflammatory response involving skin cells, such as keratinocytes, monocytes and sebocytes. These advancements have led to new insights into the underlying mechanisms which can be harnessed to develop novel treatments and diagnostic biomarkers. A major disadvantage of traditional treatment with topical antibiotics is that they induce cutaneous dysbiosis and antimicrobial resistance. Thus, future treatments would no longer aim to 'kill' C. acnes, but to maintain the skin microbiota balance allowing for tissue homeostasis, specifically, the restoration of C. acnes phylotype diversity. Here, we provide an overview of some of the key processes involved in the pathogenesis of acne, with a focus on the prominent role of C. acnes and the Th17-inflammatory pathways involved.

Myrtus communis and Celastrol enriched plant cell culture extracts control together the pivotal role of Cutibacterium acnes and inflammatory pathways in acne

INTRODUCTION

Acne is a multifactorial inflammatory disease of the pilosebaceous unit in which Cutibacterium acnes is one of the main triggers. A strong predominance of C. acnes phylotype IA1 is present in acne skin with higher biofilm organization and virulence, promoting local immuno-inflammation, especially the Th17 pathway.

OBJECTIVES

We evaluated the single and combined pharmacological properties of the plant extracts, Myrtus communis (Myrtacine®) and Celastrol enriched plant cell culture (CEE) extracts on the C. acnes/Th17 pathway.

METHODS

The effect of Myrtacine® on the virulence of C. acnes phylotype IA1 was quantified according to the expression of several related genes. The activity of Myrtacine® and CEE on the inflammatory cascade was assessed using monocytes-derived dendritic cells (Mo-DC) stimulated with membranes or biofilms of the C. acnes phylotype IA1. Finally, the effect of CEE on the Th17 pathway was studied using C. acnes stimulated sebocyte 2D cultures and 3D skin tissue models containing preactivated Th17 cells.

RESULTS

Myrtacine® had an anti-virulence effect, evident as a significant and strong inhibition of the expression of several virulence factor genes by 60%-95% compared to untreated controls. Myrtacine® and CEE significantly inhibited proinflammatory cytokine (IL-6, IL-8, IL-12p40 and TNF-α) production by Mo-DC in response to C. acnes phylotype IA1. Interestingly, these two ingredients resulted in synergistic inhibition of most cytokines when used in combination. Finally, we demonstrated an inhibitory effect of CEE, in solution or formulated at 0.3%, specifically on IL-17 release by Th17 lymphocytes in a C. acnes-stimulated sebocyte 2D cultures and by Th17-lymphocytes integrated in a 3D skin models.

CONCLUSIONS

2D and 3D models were developed to represent relevant and specific pathways involved in acne. Myrtacine® and CEE were shown to alter one or more of these pathways, indicating their potential beneficial effects on this disease.

The usefulness of a dermocosmetic containing Myrtus communis extract and azelaic acid for maintenance phase of adult female acne: Results from a randomized exploratory investigator-blinded comparative study

BACKGROUND

Acne is a very common condition. Currently, there are relatively few studies available to help guidance-based decisions for its long-term management, especially studies with cosmetic care products. We have developed a skin care product dedicated to adult female acne.

OBJECTIVES

Evaluate the efficacy and tolerance of the test product containing Myrtus communis extract and azelaic acid compared with a light moisturizing cream (LCM) in adult females in the acne maintenance phase.

METHODS

A clinical study was conducted as a Brazilian, multicentre, randomized, investigator-blinded trial in adult females with clear or almost clear facial acne after anti-acne treatment. The test group (26 subjects) applied the test product and the comparative product group (27 subjects) applied LCM. Both groups applied the products twice daily on the whole face. Subjects were evaluated every 4 weeks over 16 weeks. Efficacy was evaluated according to acne relapse; Investigator's Global Assessment (IGA); acne lesions counting; AcneQoL questionnaire; Subject Global change Assessment (SGA) of acne severity; and the number of Post-Inflammatory Hyperpigmentation (PIH) and Post-Inflammatory Erythema (PIE) lesions. Tolerance was assessed according to a 5-point scale.

RESULTS

Over 16 weeks, the number of acne relapse was more than double in the comparator compared to the test product group (eight subjects vs. three subjects respectively). There was no statistical difference in the evolution of the mean IGA from baseline between the two groups; however, 85% of subjects were assessed as clear or almost clear in the test product group and 67% in the comparative group.

CONCLUSIONS

This study demonstrated the effectiveness topical application of the test product compared to LCM on acne severity in the maintenance phase of adult female acne. Efficacy results after 16 weeks suggested a trend to limit acne relapses and a benefit of the test product in maintaining long-term remission.

The effect of the ketogenic diet on Acne: Could it be a therapeutic tool?

Acne is a chronic inflammatory disease of the pilosebaceous unit resulting from androgen-induced increased sebum production, altered keratinization, inflammation, and bacterial colonization of the hair follicles of the face, neck, chest and back by Propionibacterium acnes. Overall, inflammation and immune responses are strongly implicated in the pathogenesis of acne. Although early colonization with Propionibacterium acnes and family history may play an important role in the disease, it remains unclear exactly what triggers acne and how treatment affects disease progression. The influence of diet on acne disease is a growing research topic, yet few studies have examined the effects of diet on the development and clinical severity of acne disease, and the results have often been contradictory. Interestingly, very low-calorie ketogenic diet (VLCKD) has been associated with both significant reductions in body weight and inflammatory status through the production of ketone bodies and thus it has been expected to reduce the exacerbation of clinical manifestations or even block the trigger of acne disease. Given the paucity of studies regarding the implementation of VLCKD in the management of acne, this review aims to provide evidence from the available scientific literature to support the speculative use of VLCKD in the treatment of acne.

Network Pharmacology and Experimental Validation to Explore the Molecular Mechanisms of Compound Huangbai Liquid for the Treatment of Acne

Background

Acne is a highly prevalent skin disease, and inflammation plays an important role. Compound Huangbai Liquid (CHL) is a classical traditional Chinese medicine (TCM) with remarkable clinical therapeutic effects on acne. However, a holistic network pharmacological approach to explain the mechanism of CHL in the treatment of acne has not been explored.

Methods

In this study, active components and action targets of Compound Huangbai Liquid were assessed via BATMAN-TCM. The target genes related to acne were extracted from GeneCards, DisGeNet and OMIM databases. Venn diagrams to predict potential targets for the treatment of acne. Protein-Protein interaction (PPI) analysis was proceeded through String database to obtain the core protein, and the protein interaction network was constructed by Cytoscape 3.9.1. Gene Ontology (Go) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed on Metascape platforms and bioinformatics.com.cn. TCM-compound-target-disease network and disease-target pathway network were constructed using Cytoscape to give the visual result. Finally, the results were further verified by establishing the mouse acne animal model.

Results

This approach identified 165 active compounds, 1117 gene targets, 156 acne-related targets, and 34 potential target proteins for the treatment of acne with CHL. The biological processes were primarily related to cellular response to lipid, response to lipopolysaccharide, and regulation of secretion. The CHL was significantly associated with ten pathways including the Chagas disease and pathways in cancer. Animal experiments showed that CHL could significantly alleviate the levels of inflammatory factors and TLR4/NF-κB/p38 MAPK signaling pathway in acne.

Conclusion

This study revealed the multiple active components, multiple targets, and multiple pathways of CHL in the treatment of acne, which provided a new perspective for the study of the mechanism of traditional Chinese medicine in the treatment of acne.

Zinc and Zinc Transporters in Dermatology

Zinc is an important trace mineral in the human body and a daily intake of zinc is required to maintain a healthy status. Over the past decades, zinc has been used in formulating topical and systemic therapies for various skin disorders owing to its wound healing and antimicrobial properties. Zinc transporters play a major role in maintaining the integrity of the integumentary system by controlling zinc homeostasis within dermal layers. Mutations and abnormal function of zinc-transporting proteins can lead to disease development, such as spondylocheirodysplastic Ehlers-Danlos syndrome (SCD-EDS) and acrodermatitis enteropathica (AE) which can be fatal if left untreated. This review discusses the layers of the skin, the importance of zinc and zinc transporters in each layer, and the various skin disorders caused by zinc deficiency, in addition to zinc-containing compounds used for treating different skin disorders and skin protection.

Probiotic supplement combined with topical therapy in the treatment of mild to moderate acne: results from an Italian single centre interventional study

BACKGROUND

Acne is a chronic inflammatory disease of the pilosebaceous unit resulting from different cofactors. The alteration of the skin microbiome has recently been revealed to play a role in acne pathogenesis. Concerns with side effects of available systemic treatment for acne resulted in a greater focus on topical therapies, such as topical azelaic acid which showed to be an effective and safe treatment option for acne. The aim of our study was to evaluate the efficacy of a new treatment protocol for acne based on an oral supplement composed of biotin and 3 strains of lactic ferments combined with a topical gel composed of azelaic acid, hydroxypinacolone retinoate, and α-hydroxy acids.

METHODS

An Italian single-center interventional study was performed enrolling patients suffering from mild-to-moderate-acne. Patients were treated with a supplement based on biotin and 3 strains of lactic ferments, combined with a topical gel product (azelaic-acid, hydroxypinacolone retinoate, and α-hydroxy acids). All enrolled patients were scheduled for a total of 2 visits, a baseline visit (V0) and a follow-up visit after 60 days of treatment (V1).

RESULTS

A total of 30 patients were enrolled in the study. Between V0 (baseline) and V1 (60 days), there was a reduction of 37.4% in the GAGS Score, 40.7% in the SEBUTAPEtm Score, and 18% in the TEWL Score, and an increment of 44% in the T-Blue Test Score. No cases of serious AEs were reported in our experience.

CONCLUSIONS

Our results confirmed the promising therapeutic role of a probiotic supplement associated with topical therapy in the treatment of mild to moderate acne.

Potential roles of gut microbial tryptophan metabolites in the complex pathogenesis of acne vulgaris

Acne vulgaris is a chronic inflammatory skin disease in which the influence of gut microbiota has been implicated but without clarification of mechanisms. Gut microbiota may exert such an influence via metabolites, particularly those of tryptophan. End metabolites of tryptophan activate receptors, including aryl hydrocarbon, G protein-coupled, and pregnane X receptors to stabilize the immune microenvironment and intestinal mucosal homeostasis. Any impact on the pathogenesis of acne vulgaris remains unclear. The current review collates recent advances concerning potential roles of tryptophan metabolism in mediating skin inflammation, follicular sebaceous gland function and intestinal permeability, all of which influence the pathogenesis of acne vulgaris. The aim was to improve understanding of the pathogenesis of acne vulgaris and to expose therapeutic opportunities.

Host Microbiota Balance in Teenagers with Gum Hypertrophy Concomitant with Acne Vulgaris: Role of Oral Hygiene Associated with Topical Probiotics

Gum hypertrophy is a very frequent condition linked to orthodontic treatment, especially in teenagers, and the same time, about 80% of young adults are affected by acne vulgaris, a chronic inflammatory skin disease, typically treated with antibacterial therapy. The use of probiotics has gained popularity in the medical field, and many studies have demonstrated its effectiveness, such as the positive effects of some bacterial strains belonging to Lactobacillus species. The aim of this study is to document the effect of Lactobacillus reuteri (L. reuteri) on facial skin that was randomly observed in two orthodontic patients. We present two case reports of a 14-year-old female patient and a 15-year-old male patient suffering from acne vulgaris who, during fixed orthodontic treatment, showed clinical signs of gingivitis with high values of Full Mouth Plaque Score (FMPS) and Bleeding on Probing (BOP). The patients were treated first with professional oral hygiene sessions and Scaling and Root Planing (SRP) procedures, and then with the administration of a formulate containing L. reuteri as a probiotic. The follow-up was made at four weeks. During the follow-up analysis, both patients showed a significant clinical remission for gum hypertrophy and skin acne vulgaris.

Acne, Microbiome, and Probiotics: The Gut–Skin Axis

The objective of this narrative review was to check the influence of the human microbiota in the pathogenesis of acne and how the treatment with probiotics as adjuvant or alternative therapy affects the evolution of acne vulgaris. Acne is a chronic inflammatory skin disease involving the pilosebaceous units. The pathogenesis of acne is complex and multifactorial involving genetic, metabolic, and hormonal factors in which both skin and gut microbiota are implicated. Numerous studies have shown the bidirectionality between the intestinal microbiota and skin homeostasis, a communication mainly established by modifying the immune system. Increased data on the mechanisms of action regarding the relevance of Cutibacterium acnes, as well as the importance of the gut–skin axis, are becoming known. Diverse and varied in vitro studies have shown the potential beneficial effects of probiotics in this context. Clinical trials with both topical and oral probiotics are scarce, although they have shown positive results, especially with oral probiotics through the modulation of the intestinal microbiota, generating an anti-inflammatory response and restoring intestinal integrity, or through metabolic pathways involving insulin-like growth factor I (IGF-1). Given the aggressiveness of some standard acne treatments, probiotics should continue to be investigated as an alternative or adjuvant therapy.

The Role of Skin Immune System in Acne

Acne vulgaris is a skin disease that often occurs in adolescence and in young adulthood. The main pathogenic factors are hyperkeratinization, obstruction of sebaceous glands, stimulation of sebaceous gland secretion by androgens, and bacterial colonization of sebaceous units by Cutibacterium acnes, which promotes inflammation. Little is known about the role of skin immune cells in the development of acne lesions. The aim of the study was to try to understand the role of skin immune cells in the course of acne. Recent studies have shown that there are at least four major pathways by which Cutibacterium acnes interacts with the innate immune system to induce inflammation: through TLRs, activating inflammasomes, inducing the production of matrix metalloproteinases (MMPs), and stimulating antimicrobial peptide (AMP) activity. Cells of adaptive immune response, mainly Th1 and Th17 lymphocytes, also play an important role in the pathogenesis of acne. It is worth emphasizing that understanding the role of the skin’s immune cells in the pathogenesis of acne may, in the future, contribute to the application of modern therapeutic strategies that would avoid addiction to antibiotics, which would alleviate the spectrum of resistance that is now evident and a current threat.

Study of Interleukin-1Beta Expression in Acne Vulgaris and Acne Scars

BACKGROUND

Acne vulgaris is a multifactorial disease that mostly heals by scarring. Interleukin-1 beta (IL-1β) is a proinflammatory cytokine, suggested to play a key role in acne pathogenesis.

OBJECTIVE

To study the immunohistochemical (IHC) expression of IL1β in acne vulgaris and acne scars to evaluate its possible role in their pathogenesis and to study the relation between expression of IL1β and the clinicopathological parameters.

PATIENTS AND METHODS

This study was conducted on sixty subjects (twenty patients with acne vulgaris and twenty patients with acne scars), and twenty healthy volunteers as controls. Skin biopsies were taken from patients and controls for routine histopathological examination with Hematoxylin and Eosin (H&E) stain and IHC staining of IL-1β.

RESULTS

There was a statistically significant increase in expression of IL-1β in acne vulgaris compared to post-acne scars and controls, (p<0.001) for both. IL-1β expression was significantly positively correlated with both clinical severity of acne vulgaris (p=0.022) and severity of histopathological inflammation (p=0.011).

CONCLUSION

IL-1β expression was associated with acne vulgaris and post acne scars with significant positive correlation to clinical and histopathological severity of acne vulgaris. Thus IL-1β could be a key player cytokine in acne pathogenesis, its severity and development of post acne scars.

Algal Lipids as Modulators of Skin Disease: A Critical Review

The prevalence of inflammatory skin diseases continues to increase with a high incidence in children and adults. These diseases are triggered by environmental factors, such as UV radiation, certain chemical compounds, infectious agents, and in some cases, people with a genetic predisposition. The pathophysiology of inflammatory skin diseases such as psoriasis or atopic dermatitis, but also of skin cancers, is the result of the activation of inflammation-related metabolic pathways and the overproduction of pro-inflammatory cytokines observed in in vitro and in vivo studies. Inflammatory skin diseases are also associated with oxidative stress, overproduction of ROS, and impaired antioxidant defense, which affects the metabolism of immune cells and skin cells (keratinocytes and fibroblasts) in systemic and skin disorders. Lipids from algae have been scarcely applied to modulate skin diseases, but they are well known antioxidant and anti-inflammatory agents. They have shown scavenging activities and can modulate redox homeostasis enzymes. They can also downmodulate key inflammatory signaling pathways and transcription factors such as NF-κB, decreasing the expression of pro-inflammatory mediators. Thus, the exploitation of algae lipids as therapeutical agents for the treatment of inflammatory skin diseases is highly attractive, being critically reviewed in the present work.

Transforming growth factor beta-1 and vascular endothelial growth factor in the recovery and formation of skin scars

Relevance. Scars are multi-tissue structures that significantly reduce the quality of life of the young, able-bodied population. The most socially significant variants are represented by hypertrophic and keloid postoperative scars and scars after burns, atrophic scars after acne vulgaris and striae. Growth factors, which are also used for their treatment, play a significant role in their formation and progression. The aim of this work is to summarize data on the participation of growth factors (transforming growth factor beta-1 and vascular endothelial growth factor) in the formation of a hypertrophic or atrophic scar. Materials and Methods. The study of literary sources of scientometric scientific bases was carried out. Results and Discussion . The study showed that the duration of the scarring phases preceding it is of great importance in scar formation, their prolongation leads to chronic inflammation and the attachment of an autoimmune component, an increase in the number of myofibroblasts due to inhibition of apoptosis and an increase in the synthesis of intercellular substance and immature forms of collagen, as well as thinning of the epidermis over scar. Growth factors such as growth factor beta-1 and vascular endothelial growth factor are capable of shifting the balance of these two main pathways or towards proliferative processes, contributing to an increase in the number of blood vessels in the hemomicrocirculatory bed, the number of mast cells and total cellularity, as well as, in some cases, the synthesis of keloid - that is, the formation of a hypertrophic or keloid scar. On the contrary, the prevalence of inflammatory processes leads to a decrease in cellularity, a decrease in blood vessels and intercellular substance, as well as damage to elastin and collagen fibers, forming the phenotype of an atrophic scar or striae. Conclusion. Growth factors play a key role in scar formation, contributing to an increase in the number of blood vessels in the hemomicrocirculatory bed, the number of mast cells and total cellularity, as well as, in some cases, the synthesis of keloid - that is, the formation of a hypertrophic or keloid scar.

Identifying gaps and providing recommendations to address shortcomings in the investigation of acne sequelae by the Personalising Acne: Consensus of Experts panel

Background

The physical sequelae of acne include erythema, hyperpigmentation, and scarring, which are highly burdensome for patients. Early, effective treatment can potentially limit and prevent sequelae development, but there is a need for guidance for and evidence of prevention-oriented management to improve patient outcomes.

Objective

To identify unmet needs of acne sequelae and generate expert recommendations to address gaps in clinical guidance.

Methods

The Personalizing Acne: Consensus of Experts panel of 13 dermatologists used a modified Delphi approach to achieve a consensus on the clinical aspects of acne sequelae. A consensus was defined as ≥75% of the dermatologists voting "agree" or "strongly agree." All voting was electronic and blinded.

Results

The panel identified gaps in current guidance and made recommendations related to acne sequelae. These included identification and classification of sequelae, pertinent points to consider for patient consultations, and management aimed at reducing the development of sequelae.

Limitations

The recommendations are based on expert opinion and made in the absence of high-quality evidence.

Conclusions

The identified gaps should help inform future research and guideline development for acne sequelae. The consensus-based recommendations should also support the process of consultations throughout the patient journey, helping to reduce the development and burden of acne sequelae through improved risk factor recognition, early discussion, and appropriate management.

Post-acne hyperpigmentation: Evaluation of risk factors and the use of artificial neural network as a predictive classifier

Acne is common among young individuals. People with dark skin have a higher risk for developing pigmentary complications. Inflammation is an important factor in post-acne hyperpigmentation however other factors are also involved in developing this complication however these factors are not well studied. The aim of this study is to identify risk factors involved in post-acne hyperpigmentation. Clinical data related to acne, acne- related hyperpigmentation were collected. Data was analyzed for risk factors associated with acne pigmentation. Artificial neural network was used as predictive disease classifier for the outcome of pigmentation. Majority of patients in this study (339 patients) had dark skin phototypes (3 and 4). Post- acne hyperpigmentation was seen in more than 80% of patients. Females, darker skin color, severe acne, facial sites, and excessive sunlight exposure, squeezing or scratching lesions are important risk factors for post-acne hyperpigmentation. Post-acne hyperpigmentation is multifactorial. Several factors implicated in PAH are modifiable by adequate patient education (lesion trauma, excessive sunlight exposure). The use of ANN was helpful in predicting appearance of post-acne hyperpigmentation based on identified risk factors.

Transcriptomics Analysis Indicates Trifarotene Reverses Acne-Related Gene Expression Changes

Background and Objectives: Trifarotene is a topical retinoid selective for retinoic acid receptor gamma that was recently approved for treatment of acne vulgaris. We performed a gene expression analysis to identify the molecular and cellular impact of trifarotene treatment on acne papules. Methods: In this open-label prospective study, subjects with moderate inflammatory acne of the back were treated with trifarotene 0.005% or vehicle cream on dedicated areas for 27 days, and 4 biopsies were collected from each subject (1 from skin without a visible acne lesion and three at the site of an acne papule: one baseline, one after vehicle treatment, and one after trifarotene treatment). Large scale gene expression profiling of the biopsies was performed using Affymetrix technology, treatment-specific gene expression profiles were generated using statistical modeling, and pathway analysis was performed. Using single-cell RNAseq data, in silico deconvolution of transcriptomics data was performed to identify cellular signatures. Results: We discovered a unique set of 67 genes modulated by trifarotene that are primarily involved in cellular migration, inflammation, and extracellular matrix reorganization. Changes in cellular expression were similar in both trifarotene-treated and spontaneously-resolving lesions. However, only trifarotene treatment impacted SPP1⁺ macrophages, a subset of highly proliferative macrophages recently identified in fibrotic tissue. Conclusions: These results show that trifarotene has a novel action in acne treatment by affecting epidermal and immune components of acne pathogenesis.

Insights into the mechanism of Cymbopogan martinii essential oil in topical therapy of acne vulgaris

Aim: The present study investigated the essential oil of Cymbopogan martinii (palmarosa oil; PRO) as a potential topical therapy in acne vulgaris. Materials & methods: GC-MS profiling and biocompatibility studies of PRO were undertaken. The antimicrobial potential was assessed against Cutibacterium acnes. anti-inflammatory, antityrosinase activity and lipid peroxidation were also evaluated. Results: Geraniol was identified as the major phytoconstituent, and the oil was found to be safe for topical application. The minimum inhibitory concentration and minimum bactericidal concentration values were noted as 16 μl/ml. PRO reduced the cytokine levels of TNF-α, IL-12 and IL-8 and inhibited tyrosinase. A low concentration of the oil (up to 0.5 μl/ml) produced malondialdehyde levels equivalent to that of untreated cells. Conclusion: PRO may prove useful as a natural topical agent in the management of acne.

What the Pediatric and Adolescent Gynecology Clinician Needs to Know about Acne

Acne vulgaris is a common skin condition encountered in specialties outside of dermatology, including obstetrics and gynecology. The pathophysiology of acne is complex and includes disruption of the cutaneous microbiome, abnormal keratinization, inflammation, and hormonal influences. Various topical and systemic treatment modalities target each component of acne pathophysiology. Clinically, acne can be broken down into noninflammatory, inflammatory, or mixed subtypes. The age of the patient at presentation and signs and symptoms of hormonal imbalance might prompt workup for underlying disorders. The severity as well as type of acne dictates the type of treatment.

Surface-Modified Multifunctional Thymol-Loaded Biodegradable Nanoparticles for Topical Acne Treatment

The present work is focused on the development of novel surface-functionalized poly(lactic-co-glycolic acid) nanoparticles loaded with thymol (TH-NPs) for topical administration enhancing thymol anti-inflammatory, antioxidant and wound healing activities against acne. TH-NPs were prepared by solvent evaporation method using different surface functionalization strategies and obtaining suitable physicochemical parameters and a good short-term stability at 4 °C. Moreover, TH-NPs skin penetration and antioxidant activity were assessed in ex vivo pig skin models. Skin penetration of TH-NPs followed the follicular route, independently of the surface charge and they were able to enhance antioxidant capacity. Furthermore, antimicrobial activity against Cutibacterium acnes was evaluated in vitro by the suspension test showing improved antibacterial performance. Using human keratinocyte cells (HaCat), cytotoxicity, cellular uptake, antioxidant, anti-inflammatory and wound healing activities were studied. TH-NPs were non-toxic and efficiently internalized inside the cells. In addition, TH-NPs displayed significant anti-inflammatory, antioxidant and wound healing activities, which were highly influenced by TH-NPs surface modifications. Moreover, a synergic activity between TH-NPs and their surface functionalization was demonstrated. To conclude, surface-modified TH-NPs had proven to be suitable to be used as anti-inflammatory, antioxidant and wound healing agents, constituting a promising therapy for treating acne infection and associated inflammation.

[Acne]

Acne vulgaris is one of the most frequent dermatological diseases with a lifetime prevalence of about 85%. The clinical spectrum shows a great variety. Key factors of pathogenesis are increased sebum production, hyperkeratinization of the follicular infundibulum, inflammatory processes, and a dysbiosis of the skin microbiome. In addition to endogenous factors (e.g., disturbances of the androgen metabolism) or other hormonal changes, exogenous factors (e.g., diet, mechanical irritation or the use of inappropriate cosmetics) can also play an important role. The clinical spectrum is broad, extending from neonatal Acne (A.) to adult A., from comedonal A. to fulminant A., from cosmetic A. to A. excoriée (skin picking disorder). The psychological effects of acne can be profound and can cause a severe reduction in quality of life. Therefore, in addition to an effective therapy with regular medical check-ups and good adherence, it is always necessary to consider psychological aspects.

Interleukin19 gene polymorphism and its serum level in acne vulgaris patients

Numerous cytokines are involved in acne vulgaris pathogenesis, though few studies correlate interleukin IL-19 to acne vulgaris. So this study aimed to assess the IL-19 (rs 2243191) gene polymorphism and its serum level in acne vulgaris. This case-control study involved 90 acne vulgaris cases and 90 age- and sex-matched controls. Acne severity was assessed according to Global Acne Grading System (GAGS), and serum IL-19 was assessed by ELISA and IL-19 (rs 2243191) gene polymorphism was assessed by real time PCR. This study showed that acne cases had significantly higher IL-19 levels than controls. Also, its level was significantly higher in severe cases than moderate and mild cases. Regarding IL-19 gene polymorphism (rs 2243191), TT and CT genotypes were significantly higher in patients than in controls. The incidence of minor allele T was greater in patients than in controls. There were significant differences between IL-19 genotypes and disease severity. Serum IL-19 was significantly higher in genotypes TT and CT acne cases than in those with genotype CC. We concluded that TT genotype of IL-19 might be a hereditary risk factor for acne vulgaris development. It is associated with a high IL-19 serum level, which could be a marker of acne severity.

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An Efficacy Study of a New Radical Treatment for Acne Vulgaris Using Fat Injection

BACKGROUND

Fat grafting is a popular operative approach for rejuvenation. Some patients requiring facial fat grafting also have acne. Fat grafting may improve acne in some patients.

OBJECTIVES

The aim of this study was to assess whether fat grafting can improve acne and to analyze the mechanism of action by which such improvement occurs.

METHODS

Preoperative and postoperative digital photographs were examined retrospectively in 229 patients who underwent fat grafting to compare the numbers of inflammatory acne lesions. In addition, 18 patients with acne who were treated by injection of subdermal stromal vascular fraction gel (SVF-gel) were examined prospectively. The numbers of inflammatory acne lesions before and after treatment were measured, and changes in the levels of CD4+ T-cell infiltration were determined from immunohistochemical staining.

RESULTS

Of the 229 retrospectively evaluated patients who underwent fat grafting, 22 had acne and had complete follow-up data; in these patients, the numbers of acne lesions were significantly lower after than before treatment. The 18 patients who received subdermal SVF-gel injection showed evident improvements in inflammatory lesions after more than 1 year of follow-up. CD4+ T-cell infiltration was significantly decreased at week 4.

CONCLUSIONS

Facial fat grafting can improve inflammatory acne lesions, perhaps because adipose-derived stem cells, which are plentiful in SVF-gel, reduce CD4+ T-cell-mediated inflammation responses.

LEVEL OF EVIDENCE: 4

Updated Treatment for Acne: Targeted Therapy Based on Pathogenesis

Previous approaches to acne management have focused on the four main factors implicated in acne, namely, androgen-mediated sebogenesis (considered integral to acne), hyperkeratinization, colonization with Cutibacterium acnes, and inflammation related to both innate and adaptive mechanisms. Recent advances have facilitated potential novel approaches to acne management, as the pathophysiology and the immunological aspects related to acne and wound healing have evolved. Particular targets that have been shown to be closely involved in acne pathophysiology and wound healing include interleukin (IL)-1β, IL-17, IL-23, and tumor necrosis factor alpha (TNFα). Biological antibodies targeting IL-1β, IL-17, IL-23, and TNFα could provide novel approaches for treating severe acne and related disorders. Acne is primarily a disease associated with sebogenesis. Monosaturated free acids are important components. Insulin growth factor 1 (IGF-1) promotes the proliferation and differentiation of sebocytes and IL-1β. Research into the microbiome may also provide insights into potential future therapeutic options for acne. Scars, both atrophic and hypertrophic, are common sequelae to acne. Risk factors associated with the development of acne scars include genetic, systemic, local, and lifestyle factors. Pro-inflammatory cytokines have been shown to play a crucial role in the development of acne-induced hypertrophic scars. Treatment for extensive inflammatory keloid scarring is limited. Surgery and postoperative radiotherapy are two possible options. Transforming growth factor-β (TGFβ), IL-6, matrix metalloproteinase (MMP), IGF-1, and B cells are found in keloid or hypertrophic scar tissues. Biological antibodies targeting these cytokines may be a potential strategy for the prevention and treatment of this type of scar in the future. Future treatment for acne should embrace approaches that target the main etiological factors of acne. In particular, specific emphasis on aggressive treatment in the acute inflammatory phase to reduce the likelihood of scarring and other clinical sequelae, such as pigmentary changes would be highly desirable. Treatment for established acne-induced sequelae should also be considered.

Treatment challenges in adult female acne and future directions

Introduction: Acne is a chronic, inflammatory, and immune-mediated disease of the pilosebaceous unit, highly prevalent in adolescents. However, an increasing number of adults over 25 years old with facial acne, particularly women, have been observed. It is considered a different disease when compared to acne vulgaris. Face is the mainly involved area with inflammatory lesions and more sensitive skin, pointing out the need of a holistic approach.Areas covered: We performed a comprehensive literature search on PubMed database, up to January 2021, regarding adult female acne. We synthesized data about pathogenesis; differences compared to acne vulgaris; and treatment, with focus in the management challenges and perspectives.Expert opinion: It is essential to value the negative impact on quality of life of adult female acne, independently of severity. The disease has prolonged evolution, and patient might be resilient once the improvement, regardless of the treatment option, will just be noticeable after 3 months. Aggravating factors should be clearly discussed, such as the need of changing many habits, especially lesions manipulation. The therapeutic regimen includes make-up and tailored skin care (considering proneness to sensitivity), while anti-acne drugs should be chosen in accordance with desire to be pregnant, presence of pregnancy or breastfeeding.

50 Years of Topical Retinoids for Acne: Evolution of Treatment

Since the US Food and Drug Administration (FDA) approved tretinoin in 1971, retinoids alone or combined with other agents have become the mainstay of acne treatment. Retinoids act through binding to retinoic acid receptors, altering expression levels of hundreds of cellular proteins affecting multiple pathways involved in acne pathogenesis. Retinoids have evolved from first-generation agents, such as tretinoin, through chemical modifications resulting in a second generation (etretinate and acitretin for psoriasis), a third generation (adapalene and tazarotene) and, most recently, a fourth (trifarotene). For all topical retinoids, local irritation has been associated with poor tolerability and suboptimal adherence. Efforts to improve tolerability have utilized novel delivery systems and/or novel agents. This qualitative literature review summarizes the evolution of the four topical single-agent retinoids available for the treatment of acne in the US today and their various formulations, presenting the rationale behind their development and data from key studies.

Gene variants associated with acne vulgaris presentation and severity: a systematic review and meta-analysis

BACKGROUND

Multiple factors have been attributed to acne vulgaris predisposition and individual variations in the severity of skin symptoms, and genetics stood out as one of the major factors.

METHODS

We performed a systematic review on the genes and their variants that have been investigated for association with acne presentation and severity. A random-effect meta-analysis using the allele model (minor allele vs. major allele) was also conducted to provide an overall estimation of risk effects of frequently reported gene variants. This included a subset data of 982 acne cases and 846 controls extracted from our existing GWAS database on various allergic and skin diseases among Singapore Chinese.

RESULTS

Systematic review of 51 articles covering Asians and Caucasians found 60 genes/loci and their 100 variants implicated in acne; majority of them were in the intron, coding region/missense, and promoter regions. The commonly studied candidate genes/gene families include tumor necrosis factor (TNF), and the interleukin (IL) and cytochrome P450 (CYP) gene families. Our meta-analysis showed that most of the analyzed gene variants exhibited insignificant pooled odds ratio (pOR) and significant heterogeneity between studies. Nevertheless, we found that TNF rs1800629 A allele carriers and CYP17A1 rs743572 T allele carriers had significantly reduced mild acne risk [pOR: 0.60; 95% Confidence Interval (CI): 0.33-0.86] and severe acne risk (pOR: 0.59; 95% CI: 0.40-0.79), respectively, across populations. Overall, FST (follistatin) rs629725 A allele poses a significantly modest increased risk for acne presentation (pOR: 1.19, 95% CI: 1.14, 1.23), but neither TIMP2 (TIMP metallopeptidase inhibitor 2) rs8179090 nor CYP1A1 rs4646903 (pOR: 0.96, 95% CI: 0.80-1.12; pOR: 0.95, 95% CI: 0.83, 1.08), respectively. We discovered 15 novel SNPs in the 3' UTR region of the Toll-like Receptor 4 gene (TLR4) associated with acne presentation.

CONCLUSIONS

This systematic review and meta-analysis suggest that genes influencing inflammatory responses, specifically TNF, and genes influencing the function and activity of sebaceous glands, specifically CYP17A1 and FST, have potential risk variants for acne presentation and severity across populations. Understanding the genetic susceptibility factors and biological pathways involved in the pathogenesis of acne will help us to gain insights into developing effective acne treatments.

Acne vulgaris: role of the immune system

Acne vulgaris is a worldwide condition that has a complex pathophysiology. The knowledge of this pathology is clear in its four classic principles based on the pilosebaceous unit; there exists hyperkeratinization of its duct, increase of sebum production, anaerobic bacterias, and inflammatory response. However, new findings have explained the relationship that occurs inside the acne lesion. The immune system has a key role since it is stimulated by the other participants involved, such as phylotypes of Propionibacterium acnes (P. acnes), antimicrobial peptides (AMPs), sebaceous glands (SGs), matrix metalloproteinases (MMPs), and other immune system pathways.

Metagenomic Studies in Inflammatory Skin Diseases

Next-generation sequencing (NGS) technologies together with an improved access to compute performance led to a cost-effective genome sequencing over the past several years. This allowed researchers to fully unleash the potential of genomic and metagenomic analyses to better elucidate two-way interactions between host cells and microbiome, both in steady-state and in pathological conditions. Experimental research involving metagenomics shows that skin resident microbes can influence the cutaneous pathophysiology. Here, we review metagenome approaches to study microbiota at this barrier site. We also describe the consequences of changes in the skin microbiota burden and composition, mostly revealed by these technologies, in the development of common inflammatory skin diseases.

Essential Oil and Juice from Bergamot and Sweet Orange Improve Acne Vulgaris Caused by Excessive Androgen Secretion

Acne vulgaris is one of the most common chronic inflammatory skin diseases. Bergamot and sweet orange are rich in nutritional and functional components, which exhibit antioxidant, anti-inflammatory, and antiapoptotic effect. The aim of this study was to evaluate the potential effect of bergamot and sweet orange (juice and essential oil) on acne vulgaris caused by excessive secretion of androgen. Eighty male golden hamsters were randomly divided into 10 groups and received low or high dose of bergamot and sweet orange juice and essential oil, physiological saline, and positive drugs for four weeks, respectively. Results showed that all interventions could improve acne vulgaris by reducing the growth rate of sebaceous gland spots, inhibiting TG accumulation, decreasing the release of inflammatory cytokines (notably reducing IL-1α levels), promoting apoptosis in the sebaceous gland, and decreasing the ratio of T/E₂. Among them, bergamot and orange essential oil may have better effects (dose dependent) on alleviating acne vulgaris than the corresponding juice. In view of the large population of acne patients and the widespread use of sweet orange and bergamot, this study is likely to exert an extensive and far-reaching influence.

New technologies in topical acne therapy

The article is of an overview nature, it outlines the current understanding of the pathophysiology of acne, provides data on the role of retinoids in the treatment of dermatosis, discusses the advantages of combination therapy and new technologies in the treatment of acne.

PEG-8 Laurate Fermentation of Staphylococcus epidermidis Reduces the Required Dose of Clindamycin Against Cutibacterium acnes

The probiotic activity of skin Staphylococcus epidermidis (S. epidermidis) bacteria can elicit diverse biological functions via the fermentation of various carbon sources. Here, we found that polyethylene glycol (PEG)-8 Laurate, a carbon-rich molecule, can selectively induce the fermentation of S. epidermidis, not Cutibacterium acnes (C. acnes), a bacterium associated with acne vulgaris. The PEG-8 Laurate fermentation of S. epidermidis remarkably diminished the growth of C. acnes and the C. acnes-induced production of pro-inflammatory macrophage-inflammatory protein 2 (MIP-2) cytokines in mice. Fermentation media enhanced the anti-C. acnes activity of a low dose (0.1%) clindamycin, a prescription antibiotic commonly used to treat acne vulgaris, in terms of the suppression of C. acnes colonization and MIP-2 production. Furthermore, PEG-8 Laurate fermentation of S. epidermidis boosted the activity of 0.1% clindamycin to reduce the sizes of C. acnes colonies. Our results demonstrated, for the first time, that the PEG-8 Laurate fermentation of S. epidermidis displayed the adjuvant effect on promoting the efficacy of low-dose clindamycin against C. acnes. Targeting C. acnes by lowering the required doses of antibiotics may avoid the risk of creating drug-resistant C. acnes and maintain the bacterial homeostasis in the skin microbiome, leading to a novel modality for the antibiotic treatment of acne vulgaris.

All-Trans Retinoic Acid Enhances both the Signaling for Priming and the Glycolysis for Activation of NLRP3 Inflammasome in Human Macrophage

All-trans retinoic acid (ATRA) is a derivative of vitamin A that has many important biological functions, including the modulation of immune responses. ATRA actions are mediated through the retinoic acid receptor that functions as a nuclear receptor, either regulating gene transcription in the nucleus or modulating signal transduction in the cytoplasm. NLRP3 inflammasome is a multiprotein complex that is activated by a huge variety of stimuli, including pathogen- or danger-related molecules. Activation of the inflammasome is required for the production of IL-1β, which drives the inflammatory responses of infectious or non-infectious sterile inflammation. Here, we showed that ATRA prolongs the expression of IL-6 and IL-1β following a 2-, 6-, 12-, and 24-h LPS (100ng/mL) activation in human monocyte-derived macrophages. We describe for the first time that ATRA modulates both priming and activation signals required for NLRP3 inflammasome function. ATRA alone induces NLRP3 expression, and enhances LPS-induced expression of NLRP3 and pro-IL-1β via the regulation of signal transduction pathways, like NF-κB, p38, and ERK. We show that ATRA alleviates the negative feedback loop effect of IL-10 anti-inflammatory cytokine on NLRP3 inflammasome function by inhibiting the Akt-mTOR-STAT3 signaling axis. We also provide evidence that ATRA enhances hexokinase 2 expression, and shifts the metabolism of LPS-activated macrophages toward glycolysis, leading to the activation of NLRP3 inflammasome.

High-throughput sequencing reveals the diversity of TCR β chain CDR3 repertoire in patients with severe acne

Acne is a common chronic inflammatory skin disease, and the inflammation immune response runs through all stages of acne lesions. In this study, we use a combination of multiplex-PCR and high-throughput sequencing technologies to analyze T cell receptor β chain CDR3 (complementarity-determining region 3) in peripheral blood isolated from severe acne patients. Once compared with healthy controls, we propose to identify acne-relevant CDR3 peptides. Our results reveal that the diversity of T cell receptor β chain (TRB) CDR3 sequences in the peripheral blood of the severe acne vulgaris (SA) group differed from that of the control group. In addition, we find 10 TRB CDR3 sequences, amino acid sequences and V-J combinations with significantly different expressions between the SA group and the non-acne (NA) group (P < 0.0001). These findings may contribute to a better understanding of the role of immunity in the pathogenesis of acne and may serve as biomarkers for evaluating risk or prognosis of severe acne disease in future.

Omega-3 Versus Omega-6 Polyunsaturated Fatty Acids in the Prevention and Treatment of Inflammatory Skin Diseases

Omega-3 (ω-3) and omega-6 (ω-6) polyunsaturated fatty acids (PUFAs) are nowadays desirable components of oils with special dietary and functional properties. Their therapeutic and health-promoting effects have already been established in various chronic inflammatory and autoimmune diseases through various mechanisms, including modifications in cell membrane lipid composition, gene expression, cellular metabolism, and signal transduction. The application of ω-3 and ω-6 PUFAs in most common skin diseases has been examined in numerous studies, but their results and conclusions were mostly opposing and inconclusive. It seems that combined ω-6, gamma-linolenic acid (GLA), and ω-3 long-chain PUFAs supplementation exhibits the highest potential in diminishing inflammatory processes, which could be beneficial for the management of inflammatory skin diseases, such as atopic dermatitis, psoriasis, and acne. Due to significant population and individually-based genetic variations that impact PUFAs metabolism and associated metabolites, gene expression, and subsequent inflammatory responses, at this point, we could not recommend strict dietary and supplementation strategies for disease prevention and treatment that will be appropriate for all. Well-balanced nutrition and additional anti-inflammatory PUFA-based supplementation should be encouraged in a targeted manner for individuals in need to provide better management of skin diseases but, most importantly, to maintain and improve overall skin health.

Caveolin-1 as a possible target in the treatment for acne

Expression of caveolin-1 (Cav-1) is an important pathophysiological factor in acne. Cav-1 strongly interacts with such well-recognized etiopathogenic factors such as hyperseborrhea, follicular hyperkeratinization and pathogenicity of Cutibacterium acnes. Cav-1 is a strong negative regulator of transforming growth factor beta (TGF-β) expression. It acts as a critical determinant of autophagy, which is significantly induced in acne lesions through C. acnes and by absorption of fatty acids. Cav-1 also demonstrates different correlations with the development of innate immunity. We propose that normalization of Cav-1 expression can serve as a target in anti-acne therapy.

Retinoids as an Immunity-modulator in Dermatology Disorders

The skin is the largest epithelial surface protecting the body from invading microbes. Vitamin A plays vital roles in the host defence of the skin, including promoting epithelial cell integrity, proliferation, and differentiation and even mediating immune responses. Furthermore, vitamin A derivatives, retinoid drugs, are widely used to treat skin diseases, such as acne and psoriasis. However, the immunoregulatory mechanisms of retinoids in dermatology have not been systematically described. In this paper, we discuss the immunological functions of retinoids during disease treatment, especially in skin disorders caused by exogenous infections.

Cutibacterium acnes phylotypes diversity loss: a trigger for skin inflammatory process

BACKGROUND

Acne has long been understood as a multifactorial chronic inflammatory disease of the pilosebaceous follicle, where Cutibacterium acnes (subdivided into six main phylotypes) is a crucial factor. In parallel, the loss of microbial diversity among the skin commensal communities has recently been shown as often accompanied by inflammatory skin disorders.

OBJECTIVE

This study investigated the association of C. acnes phylotype diversity loss and the impact on Innate Immune System (IIS) activation.

METHODS

The IIS response of skin after incubation with phylotypes IA1, II or III individually and with the combination of IA1 + II + III phylotypes, was studied in an in vitro skin explant system. The inflammatory response was monitored by immunohistochemistry and ELISA assays, targeting a selection of Innate Immune Markers (IIMs) (IL-6, IL-8, IL-10, IL-17, TGF-β).

RESULTS

IIMs were significantly upregulated in skin when being incubated with phylotype IA1 alone compared with the combination IA1 + II + III. In parallel, ELISA assays confirmed these results in supernatants for IL-17, IL-8 and IL-10.

CONCLUSION

We identify the loss of C. acnes phylotype diversity as a trigger for IIS activation, leading to cutaneous inflammation. These innovative data underline the possibility to set up new approaches to treat acne. Indeed, maintaining the balance between the different phylotypes of C. acnes may be an interesting target for the development of drugs.

Atrophic acne scar: a process from altered metabolism of elastic fibres and collagen fibres based on transforming growth factor-β1 signalling

BACKGROUND

Atrophic acne scar, a persistent sequela from acne, is undesirably troubling to many patients due to its cosmetic and psychosocial aspects. Although there have been some reports emphasizing the role of early inflammatory responses in atrophic acne scarring, evolving perspectives on the detailed pathogenic processes are promptly needed.

OBJECTIVES

Examining the histological, immunological and molecular changes in early acne lesions susceptible to atrophic scarring can provide new insights to understand the pathophysiology of atrophic acne scar.

METHODS

We experimentally validated several early fundamental hallmarks accounting for the transition of early acne lesions to atrophic scars by comparing molecular profiles of skin and acne lesions between patients who were prone to scar (APS) or not (ANS).

RESULTS

In APS, compared with ANS, devastating degradation of elastic fibres and collagen fibres occurred in the dermis, followed by their incomplete recovery. Abnormally excessive inflammation mediated by innate immunity with T helper 17 and T helper 1 cells was observed. Epidermal proliferation was significantly diminished. Transforming growth factor (TGF)-β1 was drastically elevated in APS, suggesting that aberrant TGF-β1 signalling is an underlying modulator of all of these pathological processes.

CONCLUSIONS

These results may provide a basis for understanding the pathogenesis of atrophic acne scarring. Reduction of excessive inflammation and TGF-β1 signalling in early acne lesions is expected to facilitate the protection of normal extracellular matrix metabolism and ultimately the prevention of atrophic scar formation. What's already known about this topic? The dermis of atrophic acne scars shows alteration of extracellular matrix components such as collagen fibres. Inflammation in acne lesions is associated with the development of acne scars. What does this study add? Abnormalities in the metabolism of collagen fibres and elastic fibres were observed in the early developmental stages of acne lesions that were progressing into atrophic scars. Exacerbated inflammation and aberrant epidermal proliferation by increased transforming growth factor (TGF)-β1 signalling may affect the abnormal extracellular matrix metabolism. What is the translational message? Abnormal changes in elastic fibres and collagen fibres are found in the early developmental process of acne in patients who are prone to atrophic scarring. An early treatment regimen strongly inhibiting inflammation and TGF-β1 signalling to help the normal recovery of the extracellular matrix components is required to prevent atrophic scarring.