Activation of toll-like receptor 2 in acne triggers inflammatory cytokine responses

Analysis of global trends and hotspots of skin microbiome in acne: a bibliometric perspective

BACKGROUND

Acne is a chronic inflammatory condition affecting the hair follicles and sebaceous glands. Recent research has revealed significant advances in the study of the acne skin microbiome. Systematic analysis of research trends and hotspots in the acne skin microbiome is lacking. This study utilized bibliometric methods to conduct in-depth research on the recognition structure of the acne skin microbiome, identifying hot trends and emerging topics.

METHODS

We performed a topic search to retrieve articles about skin microbiome in acne from the Web of Science Core Collection. Bibliometric research was conducted using CiteSpace, VOSviewer, and R language.

RESULTS

This study analyzed 757 articles from 1362 institutions in 68 countries, the United States leading the research efforts. Notably, Brigitte Dréno from the University of Nantes emerged as the most prolific author in this field, with 19 papers and 334 co-citations. The research output on the skin microbiome of acne continues to increase, with Experimental Dermatology being the journal with the highest number of published articles. The primary focus is investigating the skin microbiome's mechanisms in acne development and exploring treatment strategies. These findings have important implications for developing microbiome-targeted therapies, which could provide new, personalized treatment options for patients with acne. Emerging research hotspots include skincare, gut microbiome, and treatment.

CONCLUSION

The study's findings indicate a thriving research interest in the skin microbiome and its relationship to acne, focusing on acne treatment through the regulation of the skin microbiome balance. Currently, the development of skincare products targeting the regulation of the skin microbiome represents a research hotspot, reflecting the transition from basic scientific research to clinical practice.

Cutibacterium acnes and its complex host interaction in prosthetic joint infection: Current insights and future directions

Cutibacterium acnes is a commensal Gram-positive anaerobic bacterium that can also act as an opportunistic pathogen in various diseases, particularly in prosthetic joint infections (PJI). Throughout this review, we delve into the current understanding of the intricate interactions between C. acnes and host cells and discuss bacterial persistence in the host. C. acnes colonization and subsequent PJI set-up represent complex processes involving bacterial adhesion, immune recognition, and host response mechanisms. We highlight existing knowledge and gaps in specific host-pathogen interactions and stress the importance of acquiring additional information to develop targeted strategies for preventing and treating C. acnes-related PIJ.

Gedunin Mitigates Cutibacterium acnes-Induced Skin Inflammation by Inhibiting the NF-κB Pathway

Background/Objectives: Cutibacterium acnes (C. acnes), a bacterium residing in hair follicles, triggers acne by inducing monocyte-mediated inflammatory cytokine production. Gedunin, a limonoid derived from Azadirachta indica (commonly known as neem), is renowned for its antifungal, antimalarial, anticancer, anti-inflammatory, and neuroprotective effects. However, its role in mitigating C. acnes-induced skin inflammation remains unexplored. This study investigates the anti-inflammatory effects of gedunin on C. acnes-induced skin inflammation and elucidates the underlying mechanisms. Methods: The anti-inflammatory activity of gedunin was assessed using RAW 264.7 mouse macrophage cells and mouse bone-marrow-derived macrophages (BMDMs). Key inflammatory mediators, including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and interleukin-6 (IL-6), were evaluated. Mechanistic studies focused on the nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways, along with the NOD-like receptor pyrin domain-containing 3 (NLRP3) inflammasome. An in vivo acne model was employed to examine gedunin's therapeutic efficacy. Results: Gedunin significantly reduced the expression of IL-1β, TNF-α, iNOS, COX-2, and IL-6 in RAW 264.7 cells. It inhibited NF-κB activation without affecting the MAPK pathways, including JNK/SAPK, ERK, and p38 MAPK. Gedunin also suppressed the activation of the NLRP3 inflammasome in BMDMs. In the mouse acne model, gedunin effectively alleviated C. acnes-induced inflammation, primarily by targeting NF-κB signaling. Conclusions: Gedunin demonstrates potential as a therapeutic agent for acne treatment by targeting key inflammatory pathways, particularly NF-κB signaling. This study highlights gedunin's promise as an alternative approach to managing C. acnes-induced skin inflammation.

The cutaneous effects of androgens and androgen-mediated sebum production and their pathophysiologic and therapeutic importance in acne vulgaris

Background: The recognition of an association between the development of acne vulgaris (AV) and pubertal hormonal changes during adolescence dates back almost 100 years. Since these formative observations, a significant role of circulating hormones in the pathophysiology of AV and other cutaneous disorders has been established.Aims: This review article aims to provide an overview of clinical and preclinical evidence supporting the influences of androgens on the skin and their therapeutic importance in AV pathophysiology.Results: The cutaneous effects of hormones are attributable, to a large extent, to the influence of steroid hormones, particularly androgens, on sebocyte development and sebum production in both sexes. Androgen-mediated excess sebum production is implicated as a necessary early step in AV pathophysiology and is therefore considered an important therapeutic target in AV treatment. Although the local production and/or activity of androgens within the skin is believed to be important in AV pathophysiology, it has received limited therapeutic attention.Conclusions: We have summarized the current evidence in support of the therapeutic benefits of targeted hormonal treatment to decrease androgen-stimulated sebum production for the effective and safe treatment of AV in both male and female patients.

Cutibacterium acnes strains associated with bone prosthesis infections cannot evade the host immune system

Introduction

Cutibacterium acnes is a commensal skin bacterium that is involved in bone prosthesis infections (BPIs) and presents low-grade clinical symptoms. C. acnes has been thought to escape the immune system at bone sites.

Material and methods

Our study was carried out on a laboratory strain and two BPI-related clinical strains, one of which surprisingly induced clinical symptoms of inflammation in the patient. We investigated the ability of these C. acnes strains to trigger in vitro human primary neutrophils (PMN) response through inflammatory mediators measurements (antibody arrays, ELISA, RT-qPCR, zymography) and activation status assessment (flow cytometry), and to induce in vivo PMN recruitment from the bloodstream in mice air-pouch model. PMN-mediated inflammation was also studied in an original in vitro model mimetic of an infected bone site that combine titanium alloy, human primary osteoblasts, human primary neutrophils and C. acnes strains.

Results

We demonstrated for the first time that both C. acnes planktonic and biofilm cultures, triggered an effective immune response by neutrophils in vitro and their recruitment in vivo. This host response was enhanced when using a strain from a patient with inflammatory signs. In an original infected prosthesis mimetic model, osteoblasts and neutrophils were able to detect C. acnes, but their response to the clinical C. acnes inflammatory strain decreased.

Conclusion

This work provides the first evidence showing that the immune cell response to pathogenic C. acnes may be tuned by nonimmune cells at the infected site, such as osteoblasts, which may promote bacterial persistence.

The Secretion of Inflammatory Cytokines Triggered by TLR2 Through Calcium-Dependent and Calcium-Independent Pathways in Keratinocytes

Keratinocytes can be activated by Cutibacterium acnes, leading to the production of proinflammatory cytokines via toll-like receptors (TLRs) 2 and 4. Although several studies have investigated keratinocytes, the mechanism of calcium-mediated activation remains unclear. Herein, we investigated whether calcium influx via TLR2 and TLR4 stimulation was involved in cytokine secretion by keratinocytes in HaCaT cells. Although TLR2 stimulation by peptidoglycan (PGN) increased intracellular calcium influx, TLR4 stimulation by lipopolysaccharide (LPS) did not increase it, as analyzed using flow cytometry with the calcium indicator Fluo-3. However, activation by either TLR2 or TLR4 ligands upregulated the intracellular calcium influx in THP-1 monocytes. Additionally, the expression of major proinflammatory cytokines and chemokines, such as interleukin (IL)-6, IL-8, IL-1α, granulocyte-macrophage colony-stimulating factor (GM-CSF), and monocyte chemoattractant protein-1 (MCP-1), was significantly increased by TLR2 in HaCaT cells. Moreover, treatment with the intracellular calcium chelator, BAPTA-AM, disrupted PGN-mediated induction of IL-6, IL-8, and MCP-1 production. Real-time quantitative polymerase chain reaction (PCR) and western blotting revealed that TLR2 stimulation induced expression of the epidermal differentiation marker keratin 1. In conclusion, TLR2-induced intracellular calcium influx plays a pivotal role in the secretion of proinflammatory cytokines, such as IL-6 and MCP-1, in keratinocytes. Moreover, the continuous influx of calcium via TLR2 activation leads to keratinization. In vitro studies using HaCaT cells provide basic research on the effect of TLR2-induced calcium on C. acnes-mediated inflammation in keratinocytes. These studies are limited in their ability to clinically predict what happens in human keratinocytes. Clinical studies on patients with acne, including three-dimensional (3D) cultures of primary keratinocytes, are required to develop new diagnostic markers for determining the severity of acne vulgaris.

Biofilm of Cutibacterium acnes: a target of different active substances

BACKGROUND

Acne vulgaris is a chronic inflammatory dermatosis. Cutibacterium acnes plays a crucial role in the acne pathophysiology. Recent works present evidence of C. acnes growing as a biofilm in cutaneous follicles. This development is currently considered one of the leading causes of C. acnes in vivo persistence and resistance to antimicrobials used to treat acne.

OBJECTIVE

Our objective was to evaluate the effects of various active compounds (clindamycin, erythromycin, doxycycline, and myrtle extract) on eight distinct, well-characterized strains of C. acnes following their growth in biofilm mode.

METHODS/RESULTS

Cutibacterium acnes isolates from phylotypes IA1 and IA2 produce more biofilm than other phylotypes. No antibiotic effect was observed either during the curative test or preventive test. Myrtle extract at 0.01% (w/v) showed significant efficacy on the biofilm for C. acnes strains (curative assays). Furthermore, it appear that myrtle extract and doxycycline together reduce the overall biomass of the biofilm. A significant dose-dependent effect was observed during the preventive test, greater than the one observed under curative conditions, with an important loss of activity of the myrtle extract observed from 0.001% (w/v) concentration onwards. Transmission electron microscopy showed that bacteria treated with myrtle extract grew biofilms much less frequently than untreated bacteria. Additionally, when the quantity of myrtle extract grew, the overall number of bacteria dropped, indicating an additional antibacterial action.

CONCLUSION

These findings support the hypothesis that the different C. acnes phylotypes have various aptitudes in forming biofilms. They also suggest that myrtle extract is a promising alternative as an anti-biofilm and antibacterial agent in fighting diseases caused by planktonic and biofilm C. acnes.

The Central Roles of Keratinocytes in Coordinating Skin Immunity

The function of keratinocytes (KCs) to form a barrier and produce cytokines is well-known, but recent progress has revealed many different roles for KCs in regulation of skin immunity. In this review, we provide an update on the current understanding of how KCs communicate with microbes, immunocytes, neurons, and other cells to form an effective immune barrier. We catalog the large list of genes and metabolites of KCs that participate in host defense and discuss the mechanisms of immune crosstalk, addressing how KCs simultaneously form a physical barrier, communicate with fibroblasts, and control immune signals. Overall, the signals sent and received by KCs are an exciting group of therapeutic targets to explore in the treatment of dermatologic disorders.

An Update on Molecular Mechanisms of Scarring-A Narrative Review

Fibroblasts, the principal cellular mediators of connective tissue remodeling, play a crucial role in the formation of physiological and pathological scars. Understanding the intricate interplay between fibroblasts and other cellular and molecular components is essential for elucidating the underlying mechanisms driving scar formation. Hypertrophic scars, keloids and atrophic scars arise from dysregulated wound healing processes characterized by persistent inflammation, aberrant collagen deposition, and impaired extracellular matrix remodeling. Fibroblasts play a central role in the pathogenesis of such pathological scars, driving aberrant extracellular matrix remodeling, subsequently contributing to the formation of raised or depressed fibrotic lesions. The investigation of complex interactions between fibroblasts and the microenvironment is crucial for developing targeted therapeutic interventions aimed at modulating fibroblast activity and improving clinical outcomes in patients with pathological scars. Further research into the molecular pathways governing fibroblast behavior and their heterogeneity holds promise for advancing scar management strategies. This narrative review was performed to shed light on the mechanisms behind scar formation, with a special focus on the role of fibroblasts in the formation of different types of scars, providing insights into the pathophysiology of these conditions. Through the analysis of current knowledge, this review seeks to identify the key cellular and molecular mechanisms involved in fibroblast activation, collagen synthesis, and extracellular matrix remodeling in hypertrophic scar, keloid, or atrophic scar formation.

Plant Phenolics in the Prevention and Therapy of Acne: A Comprehensive Review

Plants are a rich source of secondary metabolites, among which phenolics are the most abundant. To date, over 8000 various polyphenolic compounds have been identified in plant species, among which phenolic acids, flavonoids, coumarins, stilbenes and lignans are the most important ones. Acne is one of the most commonly treated dermatological diseases, among which acne vulgaris and rosacea are the most frequently diagnosed. In the scientific literature, there is a lack of a detailed scientific presentation and discussion on the importance of plant phenolics in the treatment of the most common specific skin diseases, e.g., acne. Therefore, the aim of this review is to gather, present and discuss the current state of knowledge on the activity of various plant phenolics towards the prevention and treatment of acne, including in vitro, in vivo and human studies. It was revealed that because of their significant antibacterial, anti-inflammatory and antioxidant activities, phenolic compounds may be used in the treatment of various types of acne, individually as well as in combination with commonly used drugs like clindamycin and benzoyl peroxide. Among the various phenolics that have been tested, EGCG, quercetin and nobiletin seem to be the most promising ones; however, more studies, especially clinical trials, are needed to fully evaluate their efficacy in treating acne.

Syringic acid suppresses Cutibacterium acnes-induced inflammation in human keratinocytes via regulating the NLRP3/caspase-1/IL-1β signaling axis by activating PPARγ/Nrf2-antioxidant pathway

BACKGROUND

Our previous studies have demonstrated a strong relationship betweenCutibacterium acnes(C. acnes), oxidative stress, and acne inflammation. Syringic acid (SA) is a plant widely used for its antimicrobial, anti-inflammatory, and antioxidant activities, but lacking data on acne. This study aims to investigate the effect and mechanism of SA on acne inflammation induced by C. acnes in vitro and in vivo.

METHODS

After using the SA to expose HaCaT keratinocytes, we reevaluated the effect of the SA on cell viability, cell apoptosis, ROS, CAT, SOD, and other inflammatory variables in the heat-killed C. acnes-treated HaCaT cells. Next, to induce mice with acne inflammation, ICR mice were given an intradermal injection of live C. acnes into their right ears. The effect of SA on this inflammation was then examined. Moreover, we explored the mechanism of SA on PPARγ/Nrf2 and NLRP3/caspase-1/IL-1β pathways by ELISA, immunofluorescence microscopy, and western blot assay.

RESULTS

Heat-killed C. acnes triggered remarkable cell apoptosis, ROS production, interleukin (IL)-1β, IL-18, IL-6, and TNF-α release, reduced SOD and CAT activity, and upregulated the expression of proteins in HaCaT cells, including up-regulating IL-1β, PPARγ, Nrf2, HO-1, NQO1, NLRP3, and caspase-1, whereas SA inhibited these effects by partially impairing PPARγ activation. In addition, PPARγ silencing decreased C. acnes-induced IL-1β secretion and the production of intracellular ROS, down-regulating the expression of Nrf2. Nrf2 activator (SFN) enhanced anti-inflammatory activity through antioxidant mechanisms, boosting intracellular ROS production, reducing SOD and CAT activity, and promoting the increase in ROS, HO-1, NQO1, and IL-1β levels, while PPARγ inhibitor (GW662) effectively inhibited this effect in heat-killed C. acnes-treated cells. Finally, SA also exhibited notable improvements in ear redness, swelling, and the expression of PPARγ, NLRP3, and IL-1β in vivo.

CONCLUSIONS

SA inhibited C. acnes-induced inflammation via regulating the NLRP3/caspase-1/IL-1β signaling axis by activating the PPARγ/Nrf2-antioxidant pathway, suggesting a new treatment possibility for acne vulgaris.

TRPV3 promotes sebocyte inflammation via transcriptional modulating TLR2 in acne

Acne is a common chronic inflammatory disease of the pilosebaceous unit. Transient receptor potential vanilloid 3 (TRPV3) is an ion channel that is involved in inflammatory dermatosis development. However, the involvement of TRPV3 in acne-related inflammation remains unclear. Here, we used acne-like mice and human sebocytes to examine the role of TRPV3 in the development of acne. We found that TRPV3 expression increased in the skin lesions of Propionibacterium acnes (P. acnes)-injected acne-like mice and the facial sebaceous glands (SGs) of acne patients. TRPV3 promoted inflammatory cytokines and chemokines secretion in human sebocytes and led to neutrophil infiltration surrounding the SGs in acne lesions, further exacerbating sebaceous inflammation and participating in acne development. Mechanistically, TRPV3 enhanced TLR2 level by promoting transcriptional factor phosphorylated-FOS-like antigen-1 (p-FOSL1) expression and its binding to the TLR2 promoter, leading to TLR2 upregulation and downstream NF-κB signaling activation. Genetic or pharmacological inhibition of TRPV3 both alleviated acne-like skin inflammation in mice via the TLR2-NF-κB axis. Thus, our study revealed the critical role of TRPV3 in sebaceous inflammation and indicated its potential as an acne therapeutic target.

Exploring Acne Treatments: From Pathophysiological Mechanisms to Emerging Therapies

Acne vulgaris is a common dermatological condition that can present across different ages but predominantly affects adolescents and young adults. Characterized by various lesion types, the pathogenesis of acne is complex, involving genetic, hormonal, microbial, and inflammatory factors. This review comprehensively addresses current and emerging acne management strategies, emphasizing both topical and systemic treatments, procedural therapies, and dietary modifications. Key topical agents include retinoids, benzoyl peroxide, antibiotics, and other specialized compounds. Systemic options like antibiotics, hormonal therapies, and retinoids offer significant therapeutic benefits, particularly for moderate to severe cases. Procedural treatments such as laser devices, photodynamic therapy, chemical peels, and intralesional injections present viable alternatives for reducing acne symptoms and scarring. Emerging therapies focus on novel biologics, bacteriophages, probiotics, and peptides, providing promising future options. This review underscores the importance of personalized approaches to treatment due to the multifaceted nature of acne, highlighting the potential of innovative therapies for improving patient outcomes.

Adult Female Acne: Recent Advances in Pathophysiology and Therapeutic Approaches

Adult acne is a chronic inflammatory disease of the pilosebaceous unit characterized by the excessive production of abnormal sebum favoring an imbalance of the skin microbiota and the hyperproliferation of Cutibacterium acnes and other virulent microbial strains, leading to an inflammatory environment, innate immunity overactivation, and keratinocyte hyperproliferation in hair follicles pores. Degraded keratinocytes plug the pores, consequently forming microcomedons, which can later evolve to papules, nodules, pustules and scars. Distinct from juvenile acne, in adult female acne (AFA) the symptomatology occurs or persists in postadolescence (after age 25). Although hyperandrogenism or the excessive sensitivity of androgen receptors are the main causes, AFA can be triggered by multiple factors, either including or not including androgen disturbances. The prevalence in adult women is 15–20%. Hyperandrogenism is present in 50% of cases; 70% of hyperandrogenism cases feature polycystic ovary syndrome (PCOS), a complex endocrine and metabolic condition. Genetic susceptibility occurs in 80% of acne cases, often with familial inheritance. Beyond classical stepwise therapeutic protocols (topical agents, isotretinoin, antibiotics, hormonal therapy with estrogens, progestins, spironolactone), novel approaches include the highly effective topical antiandrogen clascoterone, the management of insulin resistance by diet, exercise, stress avoidance, and adjuvant therapies such as berberine. Vaccines against the pathogenic proinflammatory C. acnes hyaluronidase A are in development.

Prostate Tissue Microbiome in Patients with Prostate Cancer: A Systematic Review

Some researchers have speculated that the prostatic microbiome is involved in the development of prostate cancer (PCa) but there is no consensus on certain microbiota in the prostatic tissue of PCa vs. healthy controls. This systematic review aims to investigate and compare the microbiome of PCa and healthy tissue to determine the microbial association with the pathogenesis of PCa. We searched MEDLINE, Embase, and Scopus databases. Articles were screened by two independent and blinded reviewers. Literature that compared the prostatic tissue microbiome of patients with PCa with benign controls was included. We found that PCa may be associated with increased Propionibacterium acnes, the herpesviridae and papillomaviridae families, and Mycoplasma genitalium, but definitive conclusions cannot be drawn from the existing data. Challenges include the difficulty of obtaining uncontaminated tissue samples and securing tissue from healthy controls. As a result, methods are varied with many studies using cancerous and "healthy" tissue from the same prostate. The organisms chosen for each study were also highly variable, making it difficult to compare studies. These issues have led to lower confidence in our results. Overall, further work is warranted to better understand the implications of the prostatic microbiome in the pathogenesis of PCa.

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.

Intracerebroventricular Cutibacterium acnes Generates Manifestations of Alzheimer's Disease-like Pathology in the Rat Hippocampus

The infection hypothesis is a new causative explanation for Alzheimer's disease (AD). In recent decades, various species of bacterial pathogens have been distinguished in the autopsy of Alzheimer's patients; however, the mechanism of bacterial contribution to AD pathology is still unknown. To explore the hypothesis, Cutibacterium acnes (C. acnes) was selected, and effects of its intracerebroventricular (ICV) inoculation in rats was evaluated. The results revealed that C. acnes causes memory impairment, which might be a consequence of upregulated Amyloid β (Aβ) deposits in the hippocampus; Aβ aggregates are co-localized with C. acnes colonies. The key point of our hypothesis is that the activation of the innate immune system by C. acnes through the TLR2/NF-κB/NLRP3 signaling pathway, eventually leads to increased neuroinflammation, which might be resulted from microgliosis and astrogliosis. Neuroinflammation increases oxidative stress and cell apoptosis. Overall, the obtained results of this study support our hypothesis that brain exposure to C. acnes prompted neuroinflammation with similar AD-like pathology.

New Molecules of Importance in the Prevention and Treatment of Acne: A Systematic Patent Review (2016-2020)

BACKGROUND

Acne is a highly prevalent disease that mainly affects the pilosebaceous units associated with sebaceous glands, causing inflammatory skin lesions and affecting the self-esteem, mental health, and quality of life of those who suffer from this disease. Different treatments exist today to prevent, reduce, and improve symptoms; however, over the years, there have been problems with bacterial resistance and slight effectiveness with prolonged use.

OBJECTIVE

The purpose of this article is based on the review of patents of new products of principal topical administration for the treatment of acne in recent years 2016-2020, to evaluate and analyze novel synthetic molecules and semi-synthetics with potential therapeutic and preventive in the acne treatment.

METHODS

A systematic review of patents was conducted through the official database of the European Patent Office - Espacenet, where the search focused on the keywords: "acne and bacteria" in the title or abstract. Only patents granted between the years 2016-2020 were included, with products having molecules with a synthetic and semi-synthetic origin, without considering natural, biological products or those used as diagnostic means.

RESULTS

A total of 19 patents were selected, most with principally antimicrobial and antiinflammatory action, where the reduction in the appearance of resistance by C. acnes is verified, and its action is complemented by inhibiting the different pathophysiological mechanisms that lead to the worsening of the disease.

CONCLUSION

Novel approaches in the treatment and prevention of acne, mainly topically, are focused on the reduction of bacterial resistance and irritation compared to current treatments. The use of combined formulations provides better results with additional benefits, improving treatment times and patient adherence.

The Microbiome and Acne: Perspectives for Treatment

The skin microbiome consists of the microorganisms populating the human skin. Cutibacterium acnes (C. acnes, formerly named Propionibacterium acnes) is recognized as a key factor in acne development, regulating inflammatory and immune pathways. Dysbiosis has been described as the imbalance in skin microbiome homeostasis and may play a role in acne pathogenesis. Microbial interference has been shown to be a contributor to healthy skin homeostasis and staphylococcal strains may exclude acne-associated C. acnes phylotypes. In this review we present an update on the skin microbiome in acne and discuss how current acne treatments such as benzoyl peroxide, orally administered isotretinoin, and antibiotics may affect the skin microbiome homeostasis. We highlight the collateral damage of acne antibiotics on the skin microbiome, including the risk of antimicrobial resistance and the dysregulation of the microbiome equilibrium that may occur even with short-term antibiotic courses. Consequently, the interest is shifting towards new non-antibiotic pharmacological acne treatments. Orally administered spironolactone is an emerging off-label treatment for adult female patients and topical peroxisome proliferator-activated receptor gamma (PPARγ) modulation is being studied for patients with acne. The potential application of topical or oral probiotics, bacteriotherapy, and phage therapy for acne are further promising areas of future research.

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.

Functional divergence of a bacterial enzyme promotes healthy or acneic skin

Acne is a dermatologic disease with a strong pathologic association with human commensal Cutibacterium acnes. Conspicuously, certain C. acnes phylotypes are associated with acne, whereas others are associated with healthy skin. Here we investigate if the evolution of a C. acnes enzyme contributes to health or acne. Two hyaluronidase variants exclusively expressed by C. acnes strains, HylA and HylB, demonstrate remarkable clinical correlation with acne or health. We show that HylA is strongly pro-inflammatory, and HylB is modestly anti-inflammatory in a murine (female) acne model. Structural and phylogenic studies suggest that the enzymes evolved from a common hyaluronidase that acquired distinct enzymatic activity. Health-associated HylB degrades hyaluronic acid (HA) exclusively to HA disaccharides leading to reduced inflammation, whereas HylA generates large-sized HA fragments that drive robust TLR2-dependent pathology. Replacing an amino acid, Serine to Glycine near the HylA catalytic site enhances the enzymatic activity of HylA and produces an HA degradation pattern intermediate to HylA and HylB. Selective targeting of HylA using peptide vaccine or inhibitors alleviates acne pathology. We suggest that the functional divergence of HylA and HylB is a major driving force behind C. acnes health- and acne- phenotype and propose targeting of HylA as an approach for acne therapy.

The Relationship Between Oxidative Stress, Selenium, and Cumulative Risk in Metabolic Syndrome

BACKGROUND/AIM

Oxidative stress in association with metabolic syndrome represents a complex disease entity that has emerged as a significant public health challenge, and it is closely linked to an elevated risk of cardiovascular disease, type 2 diabetes, and even cancer. The objective of this study was to investigate the effectiveness of selenium supplementation in managing oxidative stress while considering a well-balanced diet based on a healthy lifestyle and diet therapy.

PATIENTS AND METHODS

The study included a total of 206 participants divided into three groups: the control group consisting of 35 individuals (17.0%) named LC, the diet therapy group comprising 119 individuals (57.8%) named LD, and the diet therapy group supplemented with selenium consisting of 52 individuals (25.2%) named LD+Se. Various clinical parameters such as body mass index (BMI), weight status, fat mass, visceral fat, and sarcopenia index, as well as paraclinical parameters including the HOMA index, cholesterol, triglycerides, C-reactive protein, and HGZ, were evaluated. Additionally, oxidative stress parameters using the FORD, FORT and MIXT tests were measured.

RESULTS

Selenium supplementation, along with FORD and FORT tests, demonstrated effectiveness in individuals with chronic venous disease, with a significantly greater decrease observed in those with chronic venous disease in the LD+Se group.

CONCLUSION

Physiological aging has an important role in triggering or aggravating oxidative stress, and the use of antioxidant products such as selenium can reduce this process.

Targeting Inflammation in Acne: Current Treatments and Future Prospects

Acne is a common, chronic inflammatory condition affecting millions of people worldwide, with significant negative impact on quality of life and mental health. Acne is characterized by comedones, inflammatory papules, pustules, and nodulocystic lesions, with long-lasting sequelae including scarring and dyspigmentation, the latter of which is more common in skin of color. The four main pillars of acne pathophysiology include alteration of sebum production and concentration, hyperkeratinization of the follicular unit, Cutibacterium acnes strains, and an inflammatory immune response. Newer research has provided greater insight into these pathophysiologic categories. This greater understanding of acne pathogenesis has led to numerous new and emerging treatment modalities. These modalities include combinations of existing treatments, repurposing of existing agents historically used for other conditions, new topical treatments, novel antibiotics, topical and oral probiotics, and various procedural devices. This article will provide an overview of emerging treatments of acne and their link to our current and improved understanding of acne pathogenesis.

Exploring the Pathogenesis and Mechanism-Targeted Treatments of Rosacea: Previous Understanding and Updates

Rosacea is a chronic inflammatory skin disease characterized by recurrent erythema, flushing, telangiectasia, papules, pustules, and phymatous changes in the central area of the face. Patients with this condition often experience a significant negative impact on their quality of life, self-esteem, and overall well-being. Despite its prevalence, the pathogenesis of rosacea is not yet fully understood. Recent research advances are reshaping our understanding of the underlying mechanisms of rosacea, and treatment options based on the pathophysiological perspective hold promise to improve patient outcomes and reduce incidence. In this comprehensive review, we investigate the pathogenesis of rosacea in depth, with a focus on emerging and novel mechanisms, and provide an up-to-date overview of therapeutic strategies that target the diverse pathogenic mechanisms of rosacea. Lastly, we discuss potential future research directions aimed at enhancing our understanding of the condition and developing effective treatments.

Genome-scale metabolic modeling and in silico analysis of opportunistic skin pathogen Cutibacterium acnes

Cutibacterium acnes, one of the most abundant skin microbes found in the sebaceous gland, is known to contribute to the development of acne vulgaris when its strains become imbalanced. The current limitations of acne treatment using antibiotics have caused an urgent need to develop a systematic strategy for selectively targeting C. acnes, which can be achieved by characterizing their cellular behaviors under various skin environments. To this end, we developed a genome-scale metabolic model (GEM) of virulent C. acnes, iCA843, based on the genome information of a relevant strain from ribotype 5 to comprehensively understand the pathogenic traits of C. acnes in the skin environment. We validated the model qualitatively by demonstrating its accuracy prediction of propionate and acetate production patterns, which were consistent with experimental observations. Additionally, we identified unique biosynthetic pathways for short-chain fatty acids in C. acnes compared to other GEMs of acne-inducing skin pathogens. By conducting constraint-based flux analysis under endogenous carbon sources in human skin, we discovered that the Wood-Werkman cycle is highly activated under acnes-associated skin condition for the regeneration of NAD, resulting in enhanced propionate production. Finally, we proposed potential anti-C. acnes targets by using the model-guided systematic framework based on gene essentiality analysis and protein sequence similarity search with abundant skin microbiome taxa.

The updates and implications of cutaneous microbiota in acne

Acne is a chronic inflammatory skin disorder that profoundly impacts the quality of life of patients worldwide. While it is predominantly observed in adolescents, it can affect individuals across all age groups. Acne pathogenesis is believed to be a result of various endogenous and exogenous factors, but the precise mechanisms remain elusive. Recent studies suggest that dysbiosis of the skin microbiota significantly contributes to acne development. Specifically, Cutibacterium acnes, the dominant resident bacterial species implicated in acne, plays a critical role in disease progression. Various treatments, including topical benzoyl peroxide, systemic antibiotics, and photodynamic therapy, have demonstrated beneficial effects on the skin microbiota composition in acne patients. Of particular interest is the therapeutic potential of probiotics in acne, given its direct influence on the skin microbiota. This review summarizes the alterations in skin microbiota associated with acne, provides insight into its pathogenic role in acne, and emphasizes the potential of therapeutic interventions aimed at restoring microbial homeostasis for acne management.

Oxidative stress and metabolic syndrome in acne vulgaris: Pathogenetic connections and potential role of dietary supplements and phytochemicals

Acne vulgaris is a highly prevalent skin condition caused by androgen-induced elevated sebum secretion, abnormal keratinization, bacterial colonization, and inflammation. Current research indicates a link between acne vulgaris and the metabolic syndrome, a group of disorders that includes obesity, insulin resistance, hypertension, and dyslipidemia. This link is thought to be modulated by excessive concentrations of oxidative stress markers and chronic inflammation, which are included in the pathophysiological mechanisms shared by both conditions. Excessive generation of reactive oxygen species damages cellular components and initiates an inflammatory response, hence promoting the development of both disorders. The current narrative review focuses on the molecular implications of inflammatory, hormonal, and environmental factors in the acne-metabolic syndrome correlation. Furthermore, it outlines the current state of knowledge related to the phyto-therapeutic approach to these conditions as an adjuvant strategy to allopathic treatment, but future multicenter and larger-scale research studies are needed establish new algorithms to be included in the future management of patients with these conditions.

Anti-Inflammatory and Anti-Quorum Sensing Effect of Camellia sinensis Callus Lysate for Treatment of Acne

Cutibacterium acnes (C. acnes) is involved in the pathogenesis of acne by inducing inflammation and biofilm formation, along with other virulence factors. A Camellia sinensis (C. sinensis) callus lysate is proposed to reduce these effects. The aim of the present work is to study the anti-inflammatory properties of a callus extract from C. sinensis on C. acnes-stimulated human keratinocytes and the quorum-quenching activities. Keratinocytes were stimulated with thermo-inactivated pathogenic C. acnes and were treated with the herbal lysate (0.25% w/w) to evaluate its anti-inflammatory effect. C. acnes biofilm was developed in vitro and treated with 2.5 and 5% w/w of the lysate to evaluate quorum sensing and the lipase activity. The results showed that the lysate was able to reduce the production of interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), and C-X-C motif chemokine ligand 1 (CXCL1), and decrease the nuclear translocation of nuclear factor kappa light chain enhancer of activated B cells (NF-κB). The lysate did not show bactericidal activity but showed diminished biofilm formation, the lipase activity, and the production of autoinducer 2 (AI-2), a member of a family of signaling molecules used in quorum sensing. Therefore, the proposed callus lysate could have the potential to reduce acne-related symptoms without the eradication of C. acnes, which is part of the natural skin microbiome.

Role of Oral Retinoids in Treatment of Acne Vulgaris With a Bioinformatics-Based Perspective of Personalized Medicine

Acne vulgaris is a skin condition characterized by the inflammation or hyperactivity of sebaceous glands on the skin, which results in the creation of comedones, lesions, nodules, and perifollicular hyperkeratinization. Increased sebum production, follicular blockage, and bacterial colonization may contribute to the disease etiology. Environmental factors, hormonal imbalance, and genetic predisposition can alter the severity of the disease. Its mental and monetary effects can be problematic for the society. In this study, we examined the role of isotretinoin in the treatment of acne vulgaris based on evidence from prior research. This review literature study compiled publications on the treatment of acne vulgaris from 1985 to 2022 based on PubMed and Google Scholar publications. Additional bioinformatics analyses were accompanied by GeneCards, STRING model, and DrugBank databases. These complementary analyses were designed to obtain a better perspective of personalized medicine which is highly required for dose-precise administrations of acne vulgaris treatment. Isotretinoin has been recognized as an effective treatment for acne vulgaris, particularly in cases that have been resistant to previous medications or have resulted in scarring, according to gathered data. Oral isotretinoin inhibits the proliferation of Propionibacterium acne, a critical factor in the development of acne lesions; also, it has been shown to be effective in reducing the number of Propionibacterium-resistant patients and regulating sebum production and reducing sebaceous gland size more effectively than other treatment options resulting in general improvements in skin clarity and acne severity and reduce inflammatory in 90% of patients. In addition to its efficacy, the majority of patients have shown that oral isotretinoin is well tolerated. This review highlights the use of oral retinoids, particularly isotretinoin, as an effective and well-tolerated treatment option for acne vulgaris. It has been proven that oral isotretinoin is useful for achieving long-lasting remission in patients with severe or resistant instances. Despite the fact that oral isotretinoin is related to a number of potential harmful effects, skin dryness was the most common side effect reported by patients that can be managed with the aid of suitable monitoring and drug administration against specific genes identified by genotyping of the susceptible variants of genes involved in TGFβ signaling pathway.

Skin barrier immunology from early life to adulthood

Our skin has a unique barrier function, which is imperative for the body's protection against external pathogens and environmental insults. Although interacting closely and sharing many similarities with key mucosal barrier sites, such as the gut and the lung, the skin also provides protection for internal tissues and organs and has a distinct lipid and chemical composition. Skin immunity develops over time and is influenced by a multiplicity of different factors, including lifestyle, genetics, and environmental exposures. Alterations in early life skin immune and structural development may have long-term consequences for skin health. In this review, we summarize the current knowledge on cutaneous barrier and immune development from early life to adulthood, with an overview of skin physiology and immune responses. We specifically highlight the influence of the skin microenvironment and other host intrinsic, host extrinsic (e.g. skin microbiome), and environmental factors on early life cutaneous immunity.

Long-term exposure to low levels of ambient UVB are associated with a decreased risk of moderate-to-severe acne: A retrospective cohort study in college students

BACKGROUND

As a crucial component of solar radiation, the association between exposure to ambient ultraviolet (UV) radiation and acne remains unclear.

METHODS

This was a multicenter retrospective cohort study of incoming college students in five universities of China. Previous exposure (6 years prior to enrollment) to different wavelengths of ambient UVs were obtained from public repositories by linking to individual hometown addresses. Logistic models were applied to assess the relationship between ambient UV exposure and acne. Subgroup analysis was conducted by sun protection behaviors and time of daily sun exposure. Overall effect and single effect of exposure to four different wavelengths of UVs (305, 310, 324, and 380 nm) were estimated by Bayesian kernel machine regression (BKMR).

RESULTS

A total of 19,939 participants was included for analysis. Analysis in all participants showed a significant association between log-transformation levels of exposure to UV at 305 nm (log (UV 305 nm)) and acne (OR = 0.77, p = .021). The effect size was stronger in participants reporting no sun protection habit. Both UVs at 305 nm (OR = 0.51, p = .001) and 310 nm (OR = 0.50, p = .012) were associated a decreased risk of acne in participants reporting no sun protection habit. This inverse association was also observed in those exposed to low levels of UV (<1 h/day). The BKMR indicated consistent results that low levels of exposure to UVs combination and UVs at 305 and 310 nm were associated with a lower risk of acne.

CONCLUSION

Long-term exposure to relatively low levels of ambient UVB are associated with a decreased risk of moderate-to-severe acne in college students.

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.

Evaluation of Serum Levels of Interleukins 6, 8, 17 and 22 in Acne Vulgaris: A Cross-Sectional Study

Background

Acne vulgaris (AV) is a chronic, multifactorial, inflammatory skin disease, and it is now becoming increasingly clear that the inflammatory pathway is involved at a very early in the pathogenesis of acne. The Th17 cells, the activators of this cell line and its downstream effector cytokines, are all likely to have a critical role in inducing and maintaining the disease.

Aim

To analyse the role of interleukins (ILs) 6, 8, 17 and 22 in the pathogenesis of acne.

Materials and Methods

Sixty patients of AV and thirty age- and sex-matched controls were included in our study. Serum levels of interleukins 6, 8, 17 and 22 were determined using an enzyme-linked immunosorbent assay (ELISA), and thereafter, levels were correlated with the severity of acne.

Result

Serum levels of IL-6, IL-8, IL-17 and IL-22 were 0.15 ± 0.0174 pg/ml, 0.38 ± 0.080 pg/ml, 0.19 ± 0.0075 pg/ml and 0.23 ± 0.0152 pg/ml in cases, respectively, and 0.13 ± 0.0095 pg/ml, 0.14 ± 0.034 pg/ml, 0.13 ± 0.0033 pg/ml and 0.21 ± 0.0099 pg/ml in controls, respectively. The difference in levels between cases and controls was significant for IL-8 and IL-17, while for IL-6 and IL-22 the difference was insignificant. There was a highly significant positive correlation between IL-8 and IL-17 levels. IL-6 and IL-8 showed a significant positive correlation with the severity of disease.

Conclusion

IL-8 and IL-17 play a critical effector role in the pathogenesis of AV. IL-6-stimulated Th17 cells are likely the major producers of IL-8 in acne lesions.

Assessments of the ocular surface and meibomian gland morphology in patients with treatment-naive acne vulgaris

PURPOSE

To investigate ocular surface and meibomian glands in patients with treatment-naive acne vulgaris.

METHODS

The Ocular Surface Disease Index (OSDI) questionnaire, invasive tear film breakup time, fluorescein staining of the ocular surface, and Schirmer II test were performed for all subjects. Total eyelid and meibomian gland secretion scores were assessed. Non-contact meibography was performed with the Sirius corneal topographic device.

RESULTS

The right eyes of 35 patients with acne vulgaris and 35 healthy volunteers were included the study. While the OSDI and staining scores were significantly higher in the acne group than in the control group (p=0.01 and p=0.003, respectively), the invasive tear film breakup time and Schirmer measurements were significantly lower in the acne group (p=0.000 and p=0.003, respectively). The total eyelid and meibomian gland secretion scores were also higher in the acne group than in the control group (p=0.003 and p=0.000, respectively). On the morphological evaluation of the meibomian glands, the thickening, thinning, tortuosity, and presence of ghost areas were statistically significantly more common in the acne vulgaris group than in the control group (p=0.000, p=0.001, p=0.05, and p=0.006, respectively). The percentage of the meibomian gland loss area was significantly high in the acne vulgaris group on both upper and lower meibography. The meibomian gland loss area positively correlated with total eyelid and meibomian gland secretion scores.

CONCLUSION

Acne vulgaris may have a predisposition to meibomian gland dysfunction and ocular surface damage. Early recognition of meibomian gland and ocular surface alterations seems important, especially in acne vulgaris cases for which oral isotretinoin treatment is planned.

Pyrrolidine Dithiocarbamate Suppresses Cutibacterium acnes-Induced Skin Inflammation

Cutibacterium acnes (C. acnes), a Gram-positive anaerobic bacterium, proliferates in hair follicles and pores and causes inflammation in the skin of young people. The rapid growth of C. acnes triggers macrophages to secrete proinflammatory cytokines. Pyrrolidine dithiocarbamate (PDTC) is a thiol compound that exerts antioxidant and anti-inflammatory effects. Although the anti-inflammatory function of PDTC in several inflammatory disorders has been reported, the effect of PDTC on C. acnes-induced skin inflammation remains unexplored. In the present study, we examined the effect of PDTC on C. acnes-induced inflammatory responses and determined the mechanism by using in vitro and in vivo experimental models. We found that PDTC significantly inhibited the expression of C. acnes-induced proinflammatory mediators, such as interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), and NOD-like receptor (NLR) pyrin domain-containing 3 (NLRP3), in mouse-bone-marrow-derived macrophage (BMDM) cells. PDTC suppressed C. acnes-induced activation of nuclear factor-kappa B (NF-κB), which is the major transcription factor for proinflammatory cytokine expression. In addition, we found that PDTC inhibited caspase-1 activation and IL-1β secretion through suppressing NLRP3 and activated the melanoma 2 (AIM2) inflammasome but not the NLR CARD-containing 4 (NLRC4) inflammasome. Moreover, we found that PDTC improved C. acnes-induced inflammation by attenuating C. acnes-induced IL-1β secretion in a mouse acne model. Therefore, our results suggest that PDTC has potential therapeutic value for the amelioration of C. acnes-induced skin inflammation.

Topical phage therapy in a mouse model of Cutibacterium acnes-induced acne-like lesions

Acne vulgaris is a common neutrophil-driven inflammatory skin disorder in which Cutibacterium acnes (C. acnes) is known to play a key role. For decades, antibiotics have been widely employed to treat acne vulgaris, inevitably resulting in increased bacterial antibiotic resistance. Phage therapy is a promising strategy to combat the growing challenge of antibiotic-resistant bacteria, utilizing viruses that specifically lyse bacteria. Herein, we explore the feasibility of phage therapy against C. acnes. Eight novel phages, isolated in our laboratory, and commonly used antibiotics eradicate 100% of clinically isolated C. acnes strains. Topical phage therapy in a C. acnes-induced acne-like lesions mouse model affords significantly superior clinical and histological scores. Moreover, the decrease in inflammatory response was reflected by the reduced expression of chemokine CXCL2, neutrophil infiltration, and other inflammatory cytokines when compared with the infected-untreated group. Overall, these findings indicate the potential of phage therapy for acne vulgaris as an additional tool to conventional antibiotics.

Viaminate ameliorates Propionibacterium acnes-induced acne via inhibition of the TLR2/NF-κB and MAPK pathways in rats

Viaminate, a retinoic acid derivative developed in China, has been clinically used for acne treatment to regulate and control keratinocyte cell differentiation and proliferation, inhibit keratinization, reduce sebum secretion, and regulate immune and anti-inflammatory functions; however, its potential molecular mechanism has not yet been elucidated. Therefore, we induced ear acne in rats using Propionibacterium acnes and sebum application. Symptoms of ear redness, epidermal thickening, inflammatory reaction, keratin overproduction, subcutaneous oil, and triglyceride (TG) accumulation improved significantly in acne model rats treated with viaminate for 30 days. Transcriptome analysis of rat skin tissues suggested that viaminate had significant regulatory effects on fatty acid metabolism and cellular keratinization pathways. Molecular target prediction suggested that toll-like receptor 2 (TLR2) may be a key target of viaminate's therapeutic mechanism. Western blotting results confirmed that viaminate inhibited the TLR2 and its downstream pathways, nuclear factor-kappa B (NF-κB) [NF-κB inhibitor alpha (IκBα)/NF-κB-p65] and mitogen-activated protein kinases (MAPKs) [MAPK p38/c-Jun N-terminal kinase (JNK)/extracellular regulated kinase 1/2 (ERK1/2)] in acne vulgaris rats. In vitro studies revealed that viaminate treatment attenuated P. acnes proliferation and P. acnes-induced inflammatory response in human keratinocytes and has an inhibitory effect on the activation of NF-κB and MAPKs, while overexpression of TLR2 attenuated these effects. In conclusion, viaminate ameliorates P. acnes-induced acne by inhibiting the proliferation and inflammatory response of keratinocytes, ascribed to the deactivation of the TLR2-mediated NF-κB and MAPK pathways.

Hematological parameters in patients with acnes

OBJECTIVE

To compare complete blood count (CBC) parameters and inflammatory factors in the patients with different grade of acne vulgaris and healthy controls.

METHODS

A total of 20 patients were enrolled in this study. Patients were divided into mild group and moderate-to-severe group based on the acne severity, and compared to controls. Inflammatory factors (TNF-α, IL-6, IL-8, and IL1-α) detected by ELISA and complete blood count parameters (MPV, NLR, dNLR, PLR, LMR, and SII) obtained by routine blood tests were compared among the three group.

RESULTS

All CBC parameters were not significantly elevated in patients with acne compared to healthy controls. However, the present studies have found that the inflammatory factors in acne patients were significantly elevated relative to healthy controls, and increase with the acne grade.

CONCLUSIONS

Inflammatory factors are convenient parameters to show inflammatory response to acne vulgaris, and may be a new clinical method for judging the acne grades of objectively. Considering the use of antibiotic, we believe that this metric worth further study.

Bacteria and macrophages in the tumor microenvironment

Cancer and microbial infections are significant worldwide health challenges. Numerous studies have demonstrated that bacteria may contribute to the emergence of cancer. In this review, we assemble bacterial species discovered in various cancers to describe their variety and specificity. The relationship between bacteria and macrophages in cancer is also highlighted, and we look for ample proof to establish a biological basis for bacterial-induced macrophage polarization. Finally, we quickly go over the potential roles of metabolites, cytokines, and microRNAs in the regulation of the tumor microenvironment by bacterially activated macrophages. The complexity of bacteria and macrophages in cancer will be revealed as we gain a better understanding of their pathogenic mechanisms, which will lead to new therapeutic approaches for both inflammatory illnesses and cancer.

The relationship of skin disorders, COVID-19, and the therapeutic potential of ginseng: a review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has made significant impacts on global public health, including the development of several skin diseases that have arisen primarily as a result of the pandemic. Owing to the widespread expansion of coronavirus disease 19 (COVID-19), the development of effective treatments for these skin diseases is drawing attention as an important social issue. For many centuries, ginseng and its major active ingredients, ginsenosides and saponins, have been widely regarded as herbal medicines. Further, the anti-viral action of ginseng suggests its potential effectiveness as a therapeutic agent against COVID-19. Thus, the aim of this review was to examine the association of skin lesions with COVID-19 and the effect of ginseng as a therapeutic agent to treat skin diseases induced by COVID-19 infection. We classified COVID-19-related skin disorders into three categories: caused by inflammatory, immune, and complex (both inflammatory and immune) responses and evaluated the evidence for ginseng as a treatment for each category. This review offers comprehensive evidence on the improvement of skin disorders induced by SARS-CoV-2 infection using ginseng and its active constituents.

Evaluation of serum levels of interleukins 1-beta, 10 and 12 in patients with acne vulgaris

INTRODUCTION

One of the most prevalent skin disorders is acne vulgaris. It is a distressing problem among young adults and adolescents. The pathophysiology of AV is significantly influenced by certain immune response cells. Acne's localized tissue inflammatory reactions are brought on by the bacteria Cutibacterium acnes, which also causes the release of several inflammatory mediators.

AIM OF THE WORK

To measure the serum levels of IL-1 and IL-12, two pro-inflammatory cytokines, and IL-10, an anti-inflammatory cytokine, in AV patients and link those levels with the severity of the condition.

RESULTS

This study included 19 males and 23 females with AV(n = 42), with mean age of 21.79 ± 3.5. The control group included 19 males and 23 female (n = 42) with mean age of 22.05 ± 3.3 (p = 0.729). Serum levels of IL-1β was significantly higher in patients with AV as than controls (p < 0.001). Similarly, the serum levels of IL-12 were significantly higher in AV cases than controls (p < 0.001). On the contrary, the median IL-10 was significantly lower in AV cases than controls (p = 0.015). The correlation between serum levels of IL-1β and IL-12 in AV patients and disease severity was insignificant (r = -0.04, p = 0.404) and (r = -0.19, p = 0.118, respectively). (r = -0.19, p = 0.118) On the contrary, there was a significant negative correlation between serum levels of IL-10 in AV patients and disease severity (r = -0.43, p = 0.003).

CONCLUSION

Our results indicate significant alterations in the monocyte-derived cytokine (MDCs) profile in patients with AV, IL-1 and IL-12 serum levels rose while IL-10 levels fell, reflecting an increase in pro-inflammatory cytokines and a decrease in anti-inflammatory cytokines. These highlight the important role played by monocytes in the pathogenesis of AV.

Sulforaphene Attenuates Cutibacterium acnes-Induced Inflammation

Acne is a chronic inflammatory disease of the sebaceous gland attached to the hair follicles. Cutibacterium acnes is a major cause of inflammation caused by acne. It is well known that C. acnes secretes a lipolytic enzyme to break down lipids in sebum, and free fatty acids produced at this time accelerate the inflammatory reaction. There are several drugs used to treat acne; however, each one has various side effects. According to previous studies, sulforaphene (SFEN) has several functions associated with lipid metabolism, brain function, and antibacterial and anti-inflammatory activities. In this study, we examined the effects of SFEN on bacterial growth and inflammatory cytokine production induced by C. acnes. The results revealed that SFEN reduced the growth of C. acnes and inhibited proinflammatory cytokines in C. acnes-treated HaCaT keratinocytes through inhibiting NF-κB-related pathways. In addition, SFEN regulated the expression level of IL-1α, a representative pro-inflammatory cytokine expressed in co-cultured HaCaT keratinocytes and THP-1 monocytes induced by C. acnes. In conclusion, SFEN showed antibacterial activity against C. acnes and controlled the inflammatory response on keratinocytes and monocytes. This finding means that SFEN has potential as both a cosmetic material for acne prevention and a pharmaceutical material for acne treatment.

Lipoteichoic acid and molecular weight of hyaluronic acid could explain the late inflammatory response trigger by hyaluronic acid fillers

INTRODUCTION

Hyaluronic acid is a safe dermal filler, but sometimes late granuloma is generated. This adverse effect is an inflammatory process, and its causes are not clear. Late granuloma generation could be due to the reaction to residual components of the bacterial wall present into hyaluronic acid, such as lipoteichoic acid (LTA). Other possibility is hyaluronic acid degraded could be trigger this inflammatory reaction.

OBJECTIVE

Study possible molecular mechanism that could be implicated into the late granuloma formation. We wonder whereas inflammatory response activation is triggered by lower molecular weight hyaluronic acid or Gram-positive bacterial components as LTA.

METHODS

We analyzed one adverse case generated by hyaluronic acid injections. Our study with one nodule through chemical and immunofluorescence histologic technics.

RESULTS

In this case, observe a late granuloma without infectious process. Histological analysis shown few large Langerhans cells around fillers and multiple immunological cells infiltrated. Immunofluorescent study shown immunological cells (CD45 positives cells) with high TLR2 expression (hyaluronic acid and LTA receptor).

LIMITATIONS

The difficulty of obtaining biopsy samples of nodules implies that the number of cases analyzed is very low.

CONCLUSION

New model is proposed in which weight of hyaluronic acid and LTA could be able to trigger inflammation. This process could be mediated by TLR2 expressed in infiltrated immune cells.

In Vitro Antibacterial and Anti-Inflammatory Activity of Arctostaphylos uva-ursi Leaf Extract against Cutibacterium acnes

Cutibacterium acnes (C. acnes) is the main causative agent of acne vulgaris. The study aims to evaluate the antimicrobial activity of a natural product, Arctostaphylos uva-ursi leaf extract, against C. acnes. Preliminary chemical–physical characterization of the extract was carried out by means of FT-IR, TGA and XPS analyses. Skin permeation kinetics of the extract conveyed by a toning lotion was studied in vitro by Franz diffusion cell, monitoring the permeated arbutin (as the target component of the extract) and the total phenols by HPLC and UV-visible spectrophotometry, respectively. Antimicrobial activity and time-killing assays were performed to evaluate the effects of Arctostaphylos uva-ursi leaf extract against planktonic C. acnes. The influence of different Arctostaphylos uva-ursi leaf extract concentrations on the biofilm biomass inhibition and degradation was evaluated by the crystal violet (CV) method. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) test was used to determine the viability of immortalized human keratinocytes (HaCaT) after exposure to Arctostaphylos uva-ursi leaf extract for 24 and 48 h. Levels of interleukin (IL)-1β, IL-6, IL-8 and tumour necrosis factor (TNF)-α were quantified after HaCaT cells cotreatment with Arctostaphylos uva-ursi leaf extract and heat-killed C. acnes. The minimum inhibitory concentration (MIC) which exerted a bacteriostatic action on 90% of planktonic C. acnes (MIC₉₀) was 0.6 mg/mL. Furthermore, MIC and sub-MIC concentrations influenced the biofilm formation phases, recording a percentage of inhibition that exceeded 50 and 40% at 0.6 and 0.3 mg/mL. Arctostaphylos uva-ursi leaf extract disrupted biofilm biomass of 57 and 45% at the same concentrations mentioned above. Active Arctostaphylos uva-ursi leaf extract doses did not affect the viability of HaCaT cells. On the other hand, at 1.25 and 0.6 mg/mL, complete inhibition of the secretion of pro-inflammatory cytokines was recorded. Taken together, these results indicate that Arctostaphylos uva-ursi leaf extract could represent a natural product to counter the virulence of C. acnes, representing a new alternative therapeutic option for the treatment of acne vulgaris.

The Role of Cutibacterium acnes in Sarcoidosis: From Antigen to Treatable Trait?

Cutibacterium acnes (C. acnes, formerly Propionibacterium acnes) is considered to be a non-pathogenic resident of the human skin, as well as mucosal surfaces. However, it also has been demonstrated that C. acnes plays a pathogenic role in diseases such as acne vulgaris or implant infections after orthopedic surgery. Besides a role in infectious disease, this bacterium also seems to harbor immunomodulatory effects demonstrated by studies using C. acnes to enhance anti-tumor activity in various cancers or vaccination response. Sarcoidosis is a systemic inflammatory disorder of unknown causes. Cultures of C. acnes in biopsy samples of sarcoidosis patients, its presence in BAL fluid, tissue samples as well as antibodies against this bacterium found in serum of patients with sarcoidosis suggest an etiological role in this disease. In this review we address the antigenic as well as immunomodulatory potential of C. acnes with a focus on sarcoidosis. Furthermore, a potential role for antibiotic treatment in patients with sarcoidosis will be explored.

Particulate matter increases Cutibacterium acnes-induced inflammation in human epidermal keratinocytes via the TLR4/NF-κB pathway

Recent studies have demonstrated that particulate matter (PM) can induce oxidative stress and inflammatory responses that are related to the development or exacerbation of several inflammatory dermatoses. However, the effect of PM on acne vulgaris has yet to be determined. In this study, we induced acne-like inflammation in HEKn cells with several concentrations of Cutibacterium acnes (C. acnes) and Staphylococcus aureus peptidoglycan (PGN) to investigate whether PM exposure exacerbates acne-like inflammation and elucidate the underlying mechanisms. To confirm whether PM increases the messenger ribonucleic acid (mRNA) and protein levels of proinflammatory cytokines (IL-1α, IL-1β, IL-6, IL-8, and TNF-α) and cyclooxygenase (COX)-2 expression in C. acnes- or PGN-treated HEKn cells, we used quantitative real-time polymerase chain reactions, enzyme-linked immunosorbent assays, and western blot assays. The results demonstrated that C. acnes, PGN, and PM induced the expression of proinflammatory cytokines in a time- and dose-dependent manner at the mRNA and protein levels, respectively. Moreover, PM further increased the expression of proinflammatory cytokines, COX2, TLR4, and the phosphorylation of NF-κB in C. acnes- and PGN-treated HEKn cells. In conclusion, our results suggest that PM may exacerbate acne symptoms by increasing the inflammatory response.

Adipose-derived stem cells attenuate acne-related inflammation via suppression of NLRP3 inflammasome

BACKGROUND

Acne is a chronic facial disease caused by Propionibacterium acnes, which proliferates within sebum-blocked skin follicles and increases inflammatory cytokine production. Several therapeutic drugs and products have been proposed to treat acne, yet no single treatment that ensures long-term treatment efficacy for all patients is available. Here, we explored the use of facial autologous fat transplant of adipose-derived stem cells (ADSCs) to dramatically reduce acne lesions.

METHODS

THP-1 cells were treated with active P. acnes for 24 h at different multiplicities of infection, and alterations in inflammatory factors were detected. To study the effect of THP-1 on inflammasome-related proteins, we first co-cultured ADSCs with THP-1 cells treated with P. acnes and evaluated the levels of these proteins in the supernatant. Further, an acne mouse model injected with ADSCs was used to assess inflammatory changes.

RESULTS

Propionibacterium acnes-mediated stimulation of THP-1 cells had a direct correlation with the expression of active caspase-1 and interleukin (IL)-1β in an infection-dependent manner. ADSCs significantly reduced the production of IL-1β induced by P. acnes stimulation through the reactive oxygen species (ROS)/Nod-like receptor family pyrin domain-containing 3 (NLRP3)/caspase-1 pathway. The results showed that ADSCs inhibit the skin inflammation induced by P. acnes by blocking the NLRP3 inflammasome via reducing the secretion of IL-1β in vivo.

CONCLUSIONS

Our findings suggest that ADSCs can alter IL-1β secretion by restricting the production of mitochondria ROS, thereby inhibiting the NLRP3/caspase-1 pathway in P. acnes-induced inflammatory responses. This study indicates that anti-acne therapy can potentially be developed by targeting the NLRP3 inflammasome.

TREM2 macrophages induced by human lipids drive inflammation in acne lesions

Acne affects 1 in 10 people globally, often resulting in disfigurement. The disease involves excess production of lipids, particularly squalene, increased growth of Cutibacterium acnes, and a host inflammatory response with foamy macrophages. By combining single-cell and spatial RNA sequencing as well as ultrahigh-resolution Seq-Scope analyses of early acne lesions on back skin, we identified TREM2 macrophages expressing lipid metabolism and proinflammatory gene programs in proximity to hair follicle epithelium expressing squalene epoxidase. We established that the addition of squalene induced differentiation of TREM2 macrophages in vitro, which were unable to kill C. acnes. The addition of squalene to macrophages inhibited induction of oxidative enzymes and scavenged oxygen free radicals, providing an explanation for the efficacy of topical benzoyl peroxide in the clinical treatment of acne. The present work has elucidated the mechanisms by which TREM2 macrophages and unsaturated lipids, similar to their involvement in atherosclerosis, may contribute to the pathogenesis of acne.

T Cell Extracellular Traps: Tipping the Balance Between Skin Health and Disease

The role of extracellular traps (ETs) in the innate immune response against pathogens is well established. ETs were first identified in neutrophils and have since been identified in several other immune cells. Although the mechanistic details are not yet fully understood, recent reports have described antigen-specific T cells producing T cell extracellular traps (TETs). Depending on their location within the cutaneous environment, TETs may be beneficial to the host by their ability to limit the spread of pathogens and provide protection against damage to body tissues, and promote early wound healing and degradation of inflammatory mediators, leading to the resolution of inflammatory responses within the skin. However, ETs have also been associated with worse disease outcomes. Here, we consider host-microbe ET interactions by highlighting how cutaneous T cell-derived ETs aid in orchestrating host immune responses against Cutibacterium acnes (C. acnes), a commensal skin bacterium that contributes to skin health, but is also associated with acne vulgaris and surgical infections following joint-replacement procedures. Insights on the role of the skin microbes in regulating T cell ET formation have broad implications not only in novel probiotic design for acne treatment, but also in the treatment for other chronic inflammatory skin disorders and autoimmune diseases.