Comparison of TLR-2, TLR-4, and antimicrobial peptide levels in different lesions of acne vulgaris

Die Bedeutung von Mikrokomedonen bei der Akne: Von der Beschreibung bis zum Behandlungsansatz?: The role of microcomedones in acne: Moving from a description to treatment target?

Ein wichtiger Faktor in der Pathogenese der Akne vulgaris ist die duktale Hyperproliferation der Talgdrüsen. Diese beginnt mit der Bildung unsichtbarer Mikrokomedonen und führt im weiteren Verlauf zur Ausbildung sowohl entzündlicher als auch nicht‐entzündlicher klinischer Läsionen. Die Mikrokomedonen stehen am Anfang der zyklischen Entwicklung einer Akne, die als Komedogenese bezeichnet wird. Mikrokomedonen können mithilfe von Cyanoacrylat‐Hautablösungen, Elektronenmikroskopie, konfokaler Reflexionsmikroskopie und anderen Techniken nachgewiesen werden. Es wird angenommen, dass die Dichte und Größe von Mikrokomedonen positiv mit dem Schweregrad der Akne korreliert. Ziel dieser Übersichtsarbeit ist es, die Ursachen der Akne zusammenzufassen und darauf hinzuweisen, dass die Behandlung von Mikrokomedonen zumindest teilweise Akneläsionen beseitigen und Rückfälle verhindern könnte.

The role of microcomedones in acne: Moving from a description to treatment target?

A major factor in the pathogenesis of acne is ductal hyperproliferation in the pilosebaceous glands. This takes the form of invisible microcomedones and leads to the subsequent formation of both inflammatory and non-inflammatory clinical lesions. Microcomedones are the initial stage in the cyclical development of acne, so called comedogenesis. Microcomedones can be detected using cyanoacrylate skin surface stripping, electron microscopy, reflection confocal microscopy and other techniques. It has been proposed that the density and the size of microcomedones are positively correlated with acne severity. Thus, the purpose of this review is to summarize the root causes of acne, and suggest that treatment of microcomedones could, at least in part, resolve acne lesions and prevent relapse.

Genetic perspectives on the influence of circulating cytokines on acne: A Mendelian randomization study

Previous studies have reported that the occurrence and development of acne are closely associated with immune-inflammatory responses. Mendelian randomization was performed to further assess the causal correlation between 41 inflammatory cytokines and acne. Mendelian two-sample randomization utilized genetic variants for acne from a large open genome-wide association study (1299 cases and 211,139 controls of European ancestry) and inflammatory cytokines from a genome-wide association study abstract containing 8293 healthy participants. The causal relationship between exposure and outcome was explored primarily using an inverse variance weighting approach. In addition, multiple sensitivity analyses including MR-Egger, weighted median, simple model, weighted model, and MR-PRESSO were applied simultaneously to enhance the final results. The results suggest that il-10, MIP-1A, and SCGF-β are suggestive of the risk of acne in clinical practice (OR = 0.799, 95% CI = 0.641-0.995, P = .045; OR = 0.55, 95% CI = 0.388-0.787, P = .001; OR = 1. 152, 95% CI = 1.001-1.325, P = .048). Our study conclusively identified a causal relationship between il-10 and circulating levels of acne risk and a suggestive link between MIP-1A and SCGF-β and acne. Our study may provide greater insight into the pathogenesis of acne and develop effective management strategies for the clinic. We believe that IL-10, MIP-1A, and SCGF-β could be potential therapeutic targets for acne development.

Emerging Insights into the Applicability of Essential Oils in the Management of Acne Vulgaris

The occurrence of pustules, comedones, nodules, and cysts defines acne vulgaris, a prevalent chronic inflammatory dermatological condition. In the past few decades, essential oils extracted from varied natural sources have acquired recognition due to their potential medicinal applications in acne therapy. However, there is not yet sufficient medical data to fully characterize this interaction. Multiple factors contribute to the development of acne vulgaris, including excessive sebaceous production, inflammatory processes, hyperkeratinization, and infection with Cutibacterium acnes. Essential oils, including oregano, lavender, lemon grass, myrtle, lemon, thyme, eucalyptus, rosemary, and tea tree, have been found to possess anti-inflammatory, antioxidant, and antimicrobial properties, which may target the multifactorial causes of acne. Analytical methods for determining antioxidant potential (i.e., total phenolic content, diphenyl-1-picrylhydrazyl free radical scavenging assay, reducing power assay, ferrous ion chelating activity, thiobarbituric acid reactive species assay, β-carotene bleaching assay, etc.) are essential for the evaluation of these essential oils, and their method optimization is crucial. Further studies could include the development of novel acne treatments incorporating essential oils and an assessment of their efficacy in large clinical trials. In addition, further research is necessary to ascertain the mechanisms of action of essential oils and their optimal doses and safety profiles for optimal implementation in the management of acne vulgaris.

Lipid Metabolism Reprogramming of Immune Cells in Acne: An Update

Acne vulgaris is one of the most widespread skin conditions and the main reason for visiting a dermatologist. Inflammatory response and abnormal infiltrations of immune cells are the main pathogenesis of acne. The increased lipid is the prerequisite for the acne, and the perturbation of lipid composition and content is consistent with the severity of acne. Furthermore, the increased lipid production not only contributes to the occurrence and development of acne, but also sensitizes the function of immune cells. The lipid metabolic dysfunction aggravates the severity of local tissue and provides pro-inflammatory-cytokine cues, which indicates the crucial roles of lipid metabolism on immune cells. Recent advances have demonstrated the lipid metabolism reprogramming of various immune cells in acne lesion. The abnormal lipid accumulation, lipolysis, and fatty acid oxidation lead to the activation and differentiation of immune cells, which promotes the pro-inflammatory cytokines production. Thus, this review discusses the emerging role of lipid metabolism reprogramming of immune cells in the progress of acne and aims to constitute food for others' projects involved in acne research.

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.

Elevated expression of TLR2 and its correlation with disease activity and clinical manifestations in adult-onset Still's disease

This study investigated the role of Toll-like receptor 1 (TLR1), TLR2, TLR4, TLR7, and TLR9 in patients with adult-onset Still’s disease (AOSD). This study included 20 patients with AOSD and 15 healthy controls (HCs). TLR expression in the peripheral blood was quantified using flow cytometry; TLR expression pattern, in the skin lesions and lymph nodes (LNs) of patients with AOSD, was evaluated immunohistochemically. Significantly higher mean intensities of cells presenting TLR2 and TLR7 from whole blood were observed in patients with AOSD than in HCs. TLR2 expression in whole cells correlated with systemic scores, levels of lactate dehydrogenase and ferritin and serum levels of interleukin-1β (IL-1β), IL-6, and IL-18. The percentage of TLR2-positive inflammatory cells was higher in skin biopsy samples from patients with AOSD than those in HCs. TLR9-expressing positive inflammatory cell counts were higher in skin lesions from patients with AOSD than those in the HC, eczema, and psoriasis groups. The expression levels of TLR1, TLR4, TLR7, and TLR9 were higher in LNs of patients with AOSD than in those with T cell lymphoma and reactive lymphadenopathy. Circulating TLR2- and TLR7-positive cells may contribute to the pathogenesis of AOSD. Furthermore, immunohistochemical staining for TLRs in skin lesions and LNs may aid in differentiating AOSD from similar conditions.

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.

Red Ginseng Acidic Polysaccharides Promote the Expression of Acne-Related Inflammatory Biomarkers in Lipopolysaccharide-Treated Sebocytes and Outer Root Sheath Cells and Cutibacterium acnes-Injected Mice

Background

Although ginseng has beneficial effects largely related to their constituent ginsenosides, pharmacological effects of non-ginsenosides have been reported. Acidic polysaccharides of red ginseng (RGAP) are among the non-ginsenoside constituents that have characterized antioxidant properties.

Objective

We investigated the impact of RGAP on sebocytes and outer root sheath (ORS) cells treated with lipopolysaccharide (LPS) and in mice with Cutibacterium acnes (C. acnes)-induced inflammatory nodules.

Methods

Sebocytes and ORS cells were cultured and treated with either 0.1% dimethyl sulfoxide, 5 µg/ml LPS, 50 µg/ml RGAP or 5 µg/ml LPS+50 µg/ml RGAP for 6 and 24 hours. Real-time polymerase chain reaction, ELISA, Western blot analysis, and immunofluorescence staining were among the methods used to detect and quantify inflammatory cytokine production. Mice infected with C. acnes were treated with 2 weeks of RGAP provided in drinking water followed by immunohistochemical evaluation of inflammatory nodules.

Results

Administration of RGAP to LPS-treated sebocytes and ORS cell cultures resulted in increased expression of inflammatory cytokines like interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor-α, toll-like receptor 2, p-c-jun, p-JNK and p-iKB (p<0.05). Administration of RGAP also resulted in increased expression of LL37 in LPS-treated sebocytes and ORS cells, and increased production of sebum in LPS-treated sebocytes (p<0.05). RGAP also promoted increased expression of inflammatory biomarkers in C. acnes-associated inflammatory nodules in mice (p<0.05).

Conclusion

RGAP may exacerbate inflammatory pathology associated with acne vulgaris. Ginseng supplements may be contraindicated in patients diagnosed with inflammatory acne.

Effects of Different Doses of Systemic Isotretinoin on Eyes: A Histopathological and Immunohistochemical Study in Rats

PURPOSE

To evaluate ocular side effects associated with systemic isotretinoin histopathologically.

METHODS

In this multicenter study, a total of 15 male and 15 female rats were randomly divided into 3 equal groups according to the oral dose of isotretinoin they were administered: 0 mg/kg/d (group A), 7.5 mg/kg/d (group B), and 15 mg/kg/d (group C). Biopsy specimens were taken from the globe conjunctiva, cornea, and eyelid conjunctiva. Expression levels of human beta-defensin-1, human beta-defensin-2, toll-like receptor (TLR)-2, and TLR-4 were evaluated by immunohistochemical methods.

RESULTS

The number of goblet cells in eyelid conjunctiva was significantly lower in group B than that in group A and group C (P = 0.002). The sizes of meibomian gland acini were significantly smaller in group B and group C than those in group A (P < 0.001). Fibrosis of eyelid conjunctiva was significantly higher in group C and group B than that in group A (P = 0.002). The levels of staining of TLR-4 in the cornea with group B were significantly lower compared with group C (P = 0.035).

CONCLUSIONS

Our study suggests that isotretinoin in the early period affects eyelid conjunctiva and meibomian glands without affecting the globe conjunctiva and cornea. Occurrence of the initial symptoms of isotretinoin on the eyelids, especially on the meibomian glands, suggests that the symptoms of patients occur because of evaporative dry eye.

Altered Gene Expression in Acne Vulgaris Patients Treated by Oral Isotretinoin: A Preliminary Study

Background/Objective

The role of gene expression changes in acne patients treated by oral isotretinoin (ISO) and in influencing the ISO therapeutic effects is still unclear. In this study, we investigated the gene profiles of patients with severe acne who responded variously to ISO therapy.

Methods

The peripheral blood of 113 acne vulgaris patients (Pillsbury IV grade) was collected before treatment. After 8 weeks of oral ISO, nine acne patients were selected and divided into the following groups. A: effectively treated by ISO, group B: ineffectively treated by ISO, group C: ISO-induced acne flare-up, and 3 healthy subjects were included as control group D. The peripheral blood of patients pre- and post-treatment was subjected to high-throughput RNA sequencing technology and bioinformatics analysis of the separate groups (n = 3). The candidate genes were validated by qRT-PCR.

Results

Comparing pre- and post-oral ISO treatment, gene expression was changed as 39 genes in ISO-effective group, 345 genes in ISO-ineffective group, and 57 genes in ISO-induced acne flare-up group. Comparing the ISO-induced acne flare-up group with healthy control subjects revealed 34 upregulated genes and 23 downregulated genes, while comparing the ISO-induced acne flare-up group with ISO-ineffective patients identified 1835 changed genes. Expression of GATA2 (2.73 fold, P=0.024512), C4BPA (35.87 folds, P=0.038073), and CCR5 (2.48 folds, P=0.004681) increased in the ISO-induced acne flare-up patients. Meanwhile, the expression of DEFA3 (0.18 fold, P=0.041934), ELANE (0.14 fold, P=0.030767), MMP9 (0.41 fold, P=0.013383), and RPS4Y1 (0.00018 fold, P=0.000986) decreased when compared with ISO-ineffective patients.

Conclusion

Oral ISO treatment could temporarily alter gene expression in acne patients. ISO therapeutic mechanisms were involved, not only in regulating the inflammatory reaction but also in the process of DNA repair. GATA2, C4BPA, CCR5, DEFA3, ELANE, MMP9, and RPS4Y1 might be susceptible to genes that could participate in the ISO-induced aggravation of acne.

Staphylococcus epidermidis: A Potential New Player in the Physiopathology of Acne?

Background: Cutibacterium acnes has been identified as one of the main triggers of acne. However, increasing knowledge of the human skin microbiome raises questions about the role of other skin commensals, such as Staphylococcus epidermidis, in the physiopathology of this skin disease. Summary: This review provides an overview of current knowledge of the potential role of S. epidermidis in the physiopathology of acne. Recent research indicates that acne might be the result of an unbalanced equilibrium between C. acnes and S. epidermidis,according to dedicated interactions. Current treatments act on C. acnesonly. Other treatment options may be considered, such as probiotics derived from S. epidermidis to restore the naturally balanced microbiota or through targeting the regulation of the host’s AMP mediators. Key Messages: Research seems to confirm the beneficial role of S. epidermidis in acne by limiting C. acnes over-colonisation and inflammation.

Efficacy of Bacteriophages in Propionibacterium acnes-Induced Inflammation in Mice

Background

Bacteriophages have been introduced as living drugs for infectious diseases; thus, they may provide an alternative to conventional acne therapeutics in patients with non-responsive acne.

Objective

We investigated the effect of bacteriophages using an acne mouse model with Propionibacterium acnes-induced inflammatory nodules by clinical examination, pathology, and immunohistochemical analysis.

Methods

A human-isolated P. acnes suspension (10⁹ colony forming units/µl) was injected into the backs of HR-1 mice. Group A was used as a control, Group B was injected on the back with P. acnes 4 weeks following the initial P. acnes suspension injection, and group C was injected on the back with P. acnes and bacteriophages 4 weeks following the initial P. acnes suspension injection. Clinical and histopathological evaluations were performed.

Results

Inflammatory nodule size decreased with time in all groups. Group C showed the greatest decrease in size, followed by group B and group A. The histopathological findings showed a decrease in epidermal thickness and the number and size of microcomedone-like cysts in groups B and C compared to group A. Immunohistochemistry revealed similar expression of integrin α6, the epidermal proliferation marker, infiltration of CD4/CD8 T cells and neutrophils, and expression of myeloperoxidase, interleukin-1β, toll-like receptor-2, LL-37, and matrix metalloproteinase-2/3/9 in all three groups.

Conclusion

Using an acne mouse model with P. acnes-induced inflammatory nodules, we demonstrate that bacteriophages may constitute an alternative to conventional acne therapies. However, additional studies are needed for human applications.

Comparison of Efficacy of Doxycycline and Isotretinoin on Cutaneous Human Beta-Defensin-1 and -2 Levels in Acne Vulgaris

Background:

Recent studies have shown that human beta-defensin-1 (hBD-1) and (human beta-defensin-2 hBD-2), which are antimicrobial peptides produced by the skin, play a role in the pathogenesis of acne vulgaris (AV).

Objective:

The aim of this study was to determine the role of antimicrobial peptides in the pathogenesis of AV and enlighten the effects of doxycycline and isotretinoin in the expression of these defensins in AV.

Materials and Methods:

A total of 44 patients (22 patients in each group) with Grade 6 and 8 AV who were indicated doxycycline or isotretinoin for their treatment, and 20 healthy volunteers were included in this study. Pretreatment cutaneous samples were obtained from pustular lesions and uninvolved skin of AV patients and were repeated after the treatment. Only one biopsy was obtained from controls.

Results:

Cutaneous levels of hBD-1 and hBD-2 were significantly increased in AV patients when compared with healthy controls (P<0.05). Doxycycline therapy achieved a decrease in hBD-1 levels (P<0.05), whereas isotretinoin therapy achieved a reduction in hBD-2 levels when compared with pretreatment levels (P<0.05). Posttreatment hBD-1 and hBD-2 levels were not different between doxycycline and isotretinoin groups (P>0.05).

Conclusion:

In the light of these results, it was reasonable to assume the role of hBD-1 and hBD-2 in the pathogenesis of AV. Our results showing a significant reduction in hBD-1 staining with doxycycline treatment and in hBD-2 with isotretinoin suggested that some part of their anti-acne effect worked through these mechanisms.

Modulation of Toll Like Receptor-2 on sebaceous gland by the treatment of adult female acne

Adult female acne is a chronic inflammatory, immune-mediated disease that affects the pilosebaceous unit in women in their 20s to 40s, and is considered different from acne vulgaris. Propionibacterium acnes is recognized by TLR-2, resulting in activation of this receptor and an inflammatory response through the NFκ B pathway. This therapeutic, interventional, open, randomized, evaluator-blinded and comparative trial included 38 adult women with moderate facial acne and 10 age-matched controls, all aged between 26 and 44 years. Two treatments were performed over six months: 15% azelaic acid gel (AA) bid (n = 18) and oral contraceptive (COC) drospirenone 3 mg/ethinylestradiol .02 mg (n = 20). Biopsies were taken at baseline (control, lesion, perilesional) and at the conclusion (lesion and perilesional) of the study to evaluate TLR-2 expression by immunohistochemistry. Lesion count and blind photographic evaluation were used for efficacy. The groups were homogeneous: 70% of lesions were located in the submandibular area, 95% of participants had inflammatory lesions; of these, 50% had persistent and 50% had late-onset acne. The mean ages were 33.7 ± 5.5 and 33.1 ± 5.3 years (COC and AA group, respectively). A moderate clinical improvement was observed in both groups. No difference in TLR-2 expression in the lesion or perilesional areas was observed; however, reduced TLR-2 expression was seen in the control group. A significant reduction in expression was observed after both treatments, with no difference between the groups. This finding suggests an anti-inflammatory effect of COCs and AA in adult female acne, via modulation of the TLR-2 receptor.

Topical antibacterial medications for therapy of patient with acne

Problems of acne pathogenesis are reviewed. Efficacy evaluation and safety use of 1% clindamycin solution at patient with acne are demonstrated.

Rosacea: Molecular Mechanisms and Management of a Chronic Cutaneous Inflammatory Condition

Rosacea is a chronic cutaneous inflammatory disease that affects the facial skin. Clinically, rosacea can be categorized into papulopustular, erythematotelangiectatic, ocular, and phymatous rosacea. However, the phenotypic presentations of rosacea are more heterogeneous. Although the pathophysiology of rosacea remains to be elucidated, immunologic alterations and neurovascular dysregulation are thought to have important roles in initiating and strengthening the clinical manifestations of rosacea. In this article, we present the possible molecular mechanisms of rosacea based on recent laboratory and clinical studies. We describe the genetic predisposition for rosacea along with its associated diseases, triggering factors, and suggested management options in detail based on the underlying molecular biology. Understanding the molecular pathomechanisms of rosacea will likely aid toward better comprehending its complex pathogenesis.