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

Causal relationship between rosacea and psychiatric disorders: a bidirectional two-sample Mendelian randomization study

This study investigated the causal association between rosacea and psychiatric disorders, including major depression disorder (MDD), anxiety disorder (AD), and panic disorder (PD). A bidirectional two-sample Mendelian randomization (MR) analysis was performed. The publicly released genome-wide association summary data (GWAS) of rosacea and psychiatric disorders was used in the MR analysis. The random-effects inverse variance weighted method (IVW) was applied as the primary method, and several other estimators were used as complementary methods. MR-Egger, MR-PRESSO, Cochran's Q, and leave-one-out were performed to evaluate sensitivity and robustness. The forward MR results suggested that genetically determined rosacea did not have a causal association with the three psychiatric disorders. In the reverse analysis, the MR analyses consistently showed non-significant causal effects of these psychiatric disorders on rosacea. These findings were robust across different analytical methods. Sensitivity analyses confirmed the consistency of the results and provided no evidence of horizontal pleiotropy or outliers. A validation analysis using different datasets for the exposures and the outcomes, supporting the initial MR analysis results. Overall, the study found no evidence of a bidirectional causal relationship between genetically predicted rosacea and three psychiatric disorders despite observational studies reporting an association between rosacea and psychiatric disorders. The causal effects between these diseases need further exploration.

DNAJB2 Attenuates Rosacea Skin Inflammation and Angiogenesis by Inhibiting the Endoplasmic Reticulum Stress-mediated TLR2/Myd88/NF-κB pathway

Endoplasmic reticulum stress (ERS) has recently been proposed as a core factor in the pathogenesis and aggravation of rosacea. The roles of ERS-related genes in rosacea are largely unknown and were investigated in this study. Rosacea microarray datasets were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed ERS-related genes in rosacea patients vs. controls were screened using the Limma package, and LASSO regression was used to screen for characteristic genes. The infiltrating fraction was evaluated using ssGSEA. Clinical rosacea samples, age-matched healthy volunteers, and LL37-induced mice models were used to investigate the expression of DNAJB2 and its function. In the GSE65914 dataset, 17 differentially expressed ERS-related genes were screened. Of these, 13 were identified as characteristic genes predicting rosacea risk. The adaptive immune response, TLR signaling pathway, and chemokine signaling pathway were activated with a high risk of rosacea. After expression validation using the GSE155141 dataset, DNAJB2 was identified as a key gene. DNAJB2 expression was significantly decreased in both datasets, clinical samples, and the LL37-induced mice model. DNAJB2 overexpression could alleviate rosacea skin injury and inhibit expression of inflammatory cytokines and chemokines as well as angiogenesis. The infiltration levels of the majority of immune cell types were elevated in rosacea samples, and DNAJB2 overexpression inhibited CD4 + T cell infiltration, as well as Th1 and Th17 polarizing genes. Moreover, DNAJB2 could inhibit ERS marker proteins and the activated TLR2/Myd88/NF-κB pathway. DNAJB2 may be a novel target for rosacea treatment.

Probiotics and gut microbiota modulation: implications for skin health and disease management

The gut microbiota, consisting of a varied population of microorganisms in the digestive tract, is essential for sustaining overall human health, encompassing skin health. This review explored the intricate relationship between gut microbiota and various skin disorders, investigating the pathways through which gut dysbiosis may have impacted the development and progression of these conditions. We focused on the impact of gut microbiota on atopic dermatitis, psoriasis, acne vulgaris, acne rosacea, and melanoma. The review highlighted the potential of probiotics as a therapeutic strategy for modulating gut microbiota composition and, consequently, improving skin health. We discussed the evidence supporting the use of probiotics in managing these skin disorders and explored the mechanisms by which probiotics delivered their positive effects. Finally, we discussed the potential role of gut microbiota in other skin diseases, emphasizing the need for further research to unravel the complex interplay between the gut and the skin. Significant gaps remain in understanding the gut-skin axis, how microbial interactions contribute to skin disorders, and how to effectively manipulate the microbiome for therapeutic purposes. This review provided extensive research on the gut-skin axis, highlighting the promising prospects of modulating gut microbiota as a therapeutic strategy for various dermatological conditions.

30% Supramolecular Salicylic Acid Improved Symptoms and Skin Barrier in Papulopustular Rosacea

BACKGROUND

Rosacea is a chronic skin condition that affects millions of people worldwide, and its management continues to pose a significant challenge in dermatology.

AIM

In this study, we investigated the efficacy and safety of 30% supramolecular salicylic acid (SSA) as a treatment for papulopustular rosacea, with a particular focus on improving skin lesions, reducing persistent erythema, and enhancing skin barrier function.

METHODS

Thirty-four patients diagnosed with papulopustular rosacea were randomly divided into an experimental group treated with 30% SSA and a control group receiving a placebo. Clinical outcomes were evaluated based on lesion reduction rates, investigator severity assessment (ISA) scores, VISIA red area scores, and skin barrier, including trans-epidermal water loss (TEWL), sebum levels, stratum corneum hydration, and pH values.

RESULTS

A total of 34 patients were collected for both the experimental and control groups, with no statistical differences in age or disease severity between the groups (p > 0.05). The effective rate was 68.75% in the experimental group (p < 0.01). After treatment, the ISA score was 1.75 ± 0.68 in the experimental group and 2.40 ± 0.83 in the control group, indicating significant improvement (p < 0.05). The improvement rate of the VISIA redness score was 25.1% in the experimental group (p < 0.01). Among the 17 patients who underwent skin barrier function testing. Skin hydration significantly improved on left cheek (p < 0.05), right cheek (p < 0.01), and nose (p < 0.05) after 30% SSA treatment in experimental group. Sebum levels were significantly reduced on both cheeks and forehead (p < 0.05). No statistical differences were observed in other locations. Skin TEWL and pH value showed no changes.

CONCLUSION

30% SSA reduced papules and pustules in rosacea, improved persistent erythema, and enhanced stratum corneum hydration in the 30% SSA-treated group compared to the placebo group. No significant differences were observed in TEWL and skin pH values between the two groups. Our findings suggest that 30% SSA is an effective and safe option for managing papulopustular rosacea, offering a well-tolerated alternative to traditional treatments.

A Chlorin e6 derivative-mediated photodynamic therapy versus doxycycline for moderate-to-severe rosacea: A prospective, randomized, controlled study

BACKGROUND

Photodynamic therapy (PDT) is beneficial for managing rosacea, and chlorin e6 derivative-mediated photodynamic therapy (STBF-PDT) has demonstrated efficacy in reducing acne lesions with mild adverse reactions.

OBJECTIVES

This study aimed to assess the effectiveness and safety of STBF-PDT for the treatment of moderate-to-severe rosacea.

METHODS

In this prospective, randomised, evaluator-blind controlled study, patients with moderate-to-severe rosacea were assigned to receive up to six STBF-PDT sessions or 100 mg of doxycycline daily for eight weeks, followed by a 24-week follow-up.

RESULTS

A total of 76 patients were enrolled (38 assigned to STBF-PDT and 38 to oral doxycycline) with 69 (36 in the STBF-PDT group and 33 in the doxycycline group) completing the study. At the end of treatment, the median reduction in lesion count was 82.3 % in the STBF-PDT group and 81.8 % in the doxycycline group, indicating no significant difference between the groups. The STBF-PDT group exhibited a lower relapse rate and a significantly higher reduction in Demodex mites. Clinician's Erythema Assessment success (CEA), sensations of burning and pruritus, telangiectasia, and Rosacea-related Quality of Life (RosaQoL) scores were comparable between groups. No severe adverse reactions were observed.

CONCLUSIONS

STBF-PDT is a promising treatment option for mild-to-moderate rosacea with mild adverse reactions.

Activation of aryl hydrocarbon receptor ameliorates degranulation of LL-37 induced mast cells in rosacea through enhancing autophagy

BACKGROUND

Activation of the aryl hydrocarbon receptor (AhR) ameliorates LL-37-induced rosacea-like dermatitis in mice, whereas mast cells and cytokine overexpression are prominent features in rosacea skin.

OBJECTIVE

To evaluate the potential mechanisms of AhR activation on autophagy and degranulation of mast cells in rosacea.

METHODS

LL-37 treated mast cells were used to mimic rosacea. An AhR agonist (tapinarof) was applied to LL-37 induced mast cells. Furthermore, an autophagy agonist (RAPA) and an inhibitor (CQ) was added to investigate the mechanisms of autophagy. Western blot and RT-qPCR assessed cell degranulation (Cma1, Tpsab1) and cytokines (MMP9, TNF-α, and IL-6). Changes in cell morphology were observed under a microscope. Autophagy markers (LC3 and p62) were examined using Western blot and cellular immunofluorescence.

RESULTS

LL-37 upregulated the expressions of Cma1, Tpsab1, MMP9, TNF-α, and IL-6, which were then reduced by tapinarof treatment for 24 h. LC3B-I was converted to LC3B-II and p62 was reduced gradually with increasing concentration of tapinarof, indicating that autophagy was enhanced. RAPA enhanced the expression of LC3B-II on LL-37-induced mast cells, similar to tapinarof, while CQ partially inhibited the ability of tapinarof to induce autophagy in mast cells. Moreover, CQ reversed tapinarof's suppression of Cma1, Tpsab1, MMP9, TNF-α and IL-6 on LL-37 treated mast cells.

CONCLUSION

The present study showed that activation of AhR ameliorated degranulation of LL-37-induced mast cells in rosacea through enhancing autophagy, offering a new option for rosacea treatment.

Harnessing Ultrasonic Technologies to Treat Staphylococcus Aureus Skin Infections

The rise of antibiotic-resistant Staphylococcus aureus strains, particularly MRSA, complicates the management of skin and soft tissue infections. This review highlights ultrasonic methodologies as adjunctive therapies to combat S. aureus-driven skin infections and prevent progression to biofilm formation and chronic wounds. Low- and high-frequency ultrasound (LFU and HFU) demonstrate potential in disrupting biofilms, enhancing drug delivery, and promoting tissue repair through cavitation and microbubble activity. These approaches integrate ultrasonic frequencies with microbubbles and therapeutics, such as antibiotics and affimers, to minimize resistance and improve healing. Tailoring the bioeffects of ultrasound on skin structures through localized delivery technologies, including microneedle patches and piezoelectric systems, presents promising solutions for early intervention in skin and soft structure infections (SSSIs).

Early investigational agents for the treatment of rosacea: drugs in phase I and II clinical development

INTRODUCTION

Rosacea is a multifactorial chronic dermatologic condition with a psychosocial burden for patients. There are topical, systemic, laser, and light treatments FDA-approved, but many patients remain under- or non-responsive to those available, leaving a need for more options.

AREAS COVERED

Based on a literature search using databases, PubMed, Embase, Cochrane Library, and Clinicaltrials.gov, using keywords 'rosacea clinical trials,' we discuss treatments undergoing phase I and II clinical trials for rosacea, as well as other early clinical studies.

EXPERT OPINION

The evolving understanding of rosacea's multifaceted pathophysiology, including neurovascular dysregulation and immune responses, has led to exploration of novel treatments. Mainstays of treatment are topical and systemic antibiotics, topical vasoconstrictors, pulsed dye laser, and intense pulsed light. However, even with these treatment options, some patients remain unsatisfied with results. Addressing the underlying pathophysiology of rosacea may be more effective than a siloed approach. Therapies on the horizon, such as phosphodiesterase-4 inhibitors, biologics, topical tyrosine kinase inhibitors, neurotoxin, topical probiotics, Dermaceuticals, oral tranexamic acid, oral supplements, and neuropeptide modulators are investigated as targeted interventions. Use of lasers in synergy with topical treatments offers a multipronged personalized approach. While management remains challenging, ongoing research provides promise for additional effective and individualized treatment plans.

Isosilybin A exhibits anti-inflammatory properties in rosacea by inhibiting MAPK pathway and M1 macrophage polarization

Rosacea is a chronic inflammatory skin disease, which is prone to flares and requires continuous management and treatment. However, long-term use of drugs can lead to additional adverse drug reactions. Based on the comorbid relationship between rosacea and Parkinson's disease, bioinformatics and network pharmacology analysis were used to identify a safer drug for rosacea. It has been demonstrated that ISA has an ameliorative impact on the symptoms of Parkinson's disease. The results demonstrated that ISA exhibited anti-inflammatory properties, including reducing erythema areas and inflammatory cell infiltration in rosacea-like mice models, and inhibiting the expression of inflammatory factors in cellular inflammation models. Furthermore, the anti-inflammatory effect of ISA was associated with inhibition of the Erk, p38 and NF-κB signaling pathways and inhibition of macrophage polarization to M1 type. In addition, molecular docking and drug affinity responsive target stability experiment results indicated that VEGFA and RELA were the direct targets of ISA in the treatment for rosacea. In conclusion, these results suggested that ISA may be a potential therapeutic agent for rosacea.

Tranilast alleviates skin inflammation and fibrosis in rosacea-like mice induced by long-term exposure to LL-37

Rosacea, a prevalent chronic facial inflammatory condition, afflicts millions worldwide. Its multifaceted pathogenesis poses challenges for effective treatment. Tranilast (TR), an analog of a tryptophan metabolite, has demonstrated anti-inflammatory and anti-fibrotic properties across various diseases. Yet, its potential in rosacea treatment remains understudied. Here, we induced rosacea-like symptoms in mice via prolonged LL-37 injections and administered TR intervention. Our findings reveal that TR mitigated skin lesions, reduced skin thickness, and suppressed inflammatory cell infiltration within the dermis of LL-37 mice. Notably, TR downregulated the expression of rosacea-associated inflammatory cytokines (TNF-α, IL-6, IL-1β, and IL-18) and the antimicrobial peptide CAMP, while also inhibiting NLRP3 inflammasome activation and the TLR4 signaling pathway. Furthermore, TR attenuated LL-37-induced fibrosis and hindered the transforming growth factor-β1 (TGF-β1)/Smad2/3 pathway. In summary, our study underscores TR's therapeutic potential in rosacea by mitigating both skin inflammation and fibrosis, thereby offering a promising treatment avenue for this condition.

Serum Biomarkers IL-6 and HIF-1α in Rosacea: Assessing Their Significance in Disease Pathogenesis and Telangiectasia Formation

INTRODUCTION

Rosacea, a chronic inflammatory disease primarily affecting the central area of the face, is a complex condition whose mechanisms are still not fully understood. However, research has indicated a positive correlation between two molecules: hypoxia-inducible factor-1α (HIF-1α) and interleukin-6 (IL-6). The levels of HIF-1α in rosacea patients have yet to be assessed.

OBJECTIVES

The aim of this study was to assess the levels of HIF-1α and IL-6 in patients with rosacea in relation to both the severity of the disease and the primary and secondary clinical manifestations of the condition.

METHODS

The study included patients diagnosed with rosacea and sex-and age-matched healthy controls (N=40, N=40). Serum HIF-1α and IL-6 levels were quantified using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Compared to the control group, the patient group had significantly elevated serum levels of HIF-1α and IL-6. A positive correlation was found between the level of HIF-1α and the severity of the disease (r=0.374, P=0.017); furthermore, a significant association was observed between the presence of telangiectasia, one of the primary manifestations, and HIF-1α (z=2.401, P=0.016).

CONCLUSION

The significantly elevated levels of IL-6 and HIF-1α in patients with rosacea compared to the control group support the hypothesis that these molecules play a role in the pathogenesis of the disease. The correlation between HIF-1α and the severity of the disease, and its significant elevation in patients with telangiectasia, suggest its potential involvement in the pathogenesis of the disease, particularly in the formation of telangiectasia.

Azelaic Acid: Mechanisms of Action and Clinical Applications

AZA is a non-phenolic, saturated dicarboxylic acid with nine carbon atoms, naturally produced by the yeast Malassezia. It has diverse physiological activities, including antibacterial, anti-keratinizing, antimelanogenic, antioxidant and anti-inflammatory effects. AZA is widely used in dermatology and is FDA-approved for treating papulopustular rosacea. It also shows significant efficacy in acne vulgaris and melasma. This review summarizes the mechanisms of action and clinical applications of AZA, aiming to provide theoretical support for its clinical and cosmetic use and to facilitate further research.

Drug repositioning for rosacea disease: Biological TARGET identification, molecular docking, pharmacophore mapping, and molecular dynamics analysis

Rosacea is a chronic dermatological condition that currently lacks a clear treatment approach due to an uncomprehensive knowledge of its pathogenesis. The main obstacle lies in understanding its etiology and the mode of action of the different drugs used. This study aims to clarify these aspects by employing drug repositioning. Using an in silico approach, we performed a transcriptomic analysis comparing samples from individuals with diverse types of rosacea to those from healthy controls to identify genes deregulated in this disease. Subsequently, we realized molecular docking and molecular dynamics studies to assess the binding affinity of drugs currently used to treat rosacea and drugs that target proteins interacting with, and thus affecting, proteins deregulated in rosacea. Our findings revealed that the downregulation of SKAP2 and upregulation of S100A7A in rosacea, could be involved in the pathogenesis of the disease. Furthermore, considering the drugs currently used for rosacea management, we demonstrated stable interactions between isotretinoin and BFH772 with SKAP2, and permethrin and PAC-14028 with S100A7A. Similarly, considering drugs targeting SKAP2 and S100A7A interactome proteins, we found that pitavastatin and dasatinib exert stable interactions with SKAP2, and lovastatin and tirbanibulin with S100A7A. In addition, we determine that the types of bonds involved in the interactions were different in SKAP2 from S100A7A. The drug-SKAP2 interactions are hydrogen bonds, whereas the drug-S100A7A interactions are of the hydrophobic type. In conclusion, our study provides evidence for the possible contribution of SKAP2 and S100A7A to rosacea pathology. Furthermore, it provides significant information on the molecular interactions between drugs and these proteins, highlighting the importance of considering structural features and binding interactions in the design of targeted therapies for skin disorders such as rosacea.

Efficacy of Treatments in Reducing Inflammatory Lesion Count in Rosacea: A Systematic Review

INTRODUCTION

Rosacea is a chronic inflammatory skin condition affecting approximately 5.5% of the global population. Patients present heterogeneously with a mix of features in the central facial region, of which papules and pustules are considered to be a major feature. The identification of effective treatments for reducing inflammatory lesions in rosacea can alleviate the psychosocial burden that many rosacea patients experience, including reduced self-esteem, anxiety, and social withdrawal. The objective of this systematic review is to determine the effectiveness of topical and systemic therapies in reducing lesion count in rosacea patients.

METHODS/RESULTS

Medline, Embase, and Cochrane CENTRAL databases were searched, resulting in the inclusion of 43 clinical trials reporting on a total of 18,347 rosacea patients. The most well-studied treatments include ivermectin, metronidazole, azelaic acid, minocycline, and doxycycline. Oral isotretinoin was the most effective treatment in reducing inflammatory lesions and may be recommended for severe recalcitrant cases of rosacea.

CONCLUSIONS

Several topical and systemic therapies have demonstrated efficacy in reducing inflammatory lesion count in rosacea patients, with mechanisms of action centred around suppressing inflammation and killing Demodex folliculorum mites. Additional research is required to determine effective combination therapies in rosacea.

Correlation between cigarette smoking and alcohol consumption and Rosacea: A two-sample Mendelian randomization study

BACKGROUND

Controversy persists regarding the causal relationship between Cigarette smoking, alcohol consumption, and Rosacea. This paper employs the Mendelian randomization (MR) method to elucidate the correlation between Cigarette smoking, alcohol consumption, and Rosacea. The aim is to contribute valuable insights to aid in the prevention and early treatment of Rosacea.

METHOD

Summary datasets for cigarette smoking parameters (Cigarettes smoked per day, Smoking status: Previous, smoking status: Current) and alcohol consumption (Alcoholic drinks per week) were selected alongside data for Rosacea from genome-wide association studies (GWAS). The Two-sample MR method was employed to analyze the correlation between cigarette smoking, alcohol consumption, and Rosacea. Various MR analysis methods, including inverse variance weighting (IVW), MR-Egger, Simple Mode, Weighted Mode, and Weighted Median, were chosen. IVW served as the primary analysis method.

RESULTS

The results indicate a significant negative association between Cigarettes smoked per day and Rosacea. Moreover, a significant positive correlation was observed between Smoking status: Previous and Rosacea. However, no significant associations were found between Smoking status: Current, Alcoholic drinks per week, and Rosacea.

CONCLUSION

This study provides further clarity on the association between cigarette smoking, drinking, and Rosacea through a two-sample MR analysis. Notably, the number of cigarettes smoked per day appears to be associated with a reduced incidence of Rosacea, while cigarette smoking cessation may increase the risk. Surprisingly, alcohol consumption does not emerge as a significant risk factor for Rosacea. These findings contribute to a nuanced understanding of the complex relationship between lifestyle factors and the occurrence of Rosacea, offering potential insights for preventive measures and early intervention.

Important Roles of Interleukin-36, Interleukin-37, and Interleukin-38 Cytokines in the Pathogenesis of Rosacea

Background

Rosacea is a chronic inflammatory skin disease. Previous studies have determined that IL-36, IL-37, and IL-38 may play a role in the pathogenesis of various inflammatory diseases.

Aims and Objectives

The present study aims to evaluate the relationship of these cytokines with rosacea.

Materials and Methods

A total of 100 individuals, including 50 patients with rosacea and 50 healthy controls, were included in the study. IL-36, IL-37, and IL-38 levels were measured using the ELISA method by taking serum samples from all participants.

Results

The mean serum levels of IL-36, IL-37, and IL-38 in the patient group were 52.17 ± 24.07 pg/ml, 18.46 ± 8.18 pg/ml, and 25.74 ± 8.36 ng/l, respectively. The mean serum levels of IL-36, IL-37, and IL-38 in the control group were 32.99 ± 19.90 pg/ml, 44.61 ± 22.27 pg/ml, and 45.61 ± 17.32 ng/l, respectively. The difference between the serum levels of IL-36, IL-37, and IL-38 in the patient and control groups was statistically significant (P < 0.001).

Conclusion

Based on these findings, an increase in IL-36 and a decrease in IL-37 and IL-38 may contribute to the pathogenesis of rosacea. Future rosacea treatments could target and/or interact with these possible steps in the pathogenesis of rosacea.

Oroxylin A suppress LL-37 generated rosacea-like skin inflammation through the modulation of SIRT3-SOD2-NF-κB signaling pathway

Rosacea is a long-term inflammatory skin disease associated with the dysfunction of vascular and immunological systems. Treatment options for rosacea are difficult to implement. Oroxylin A(OA), a traditional Chinese medicine, has anti-inflammation effects in a variety of inflammatory diseases. However, it is not known that whether OA exerts protective effects against LL-37-induced rosacea. In this study, bioinformatics analyses showed that the mechanisms of rosacea and the pharmacological targets of OA were highly overlapped. Subsequently, it was shown that the administration of OA resulted in a notable amelioration of rosacea-like skin lesions, as evidenced by a reduction in immune cell infiltration, modulation of cytokine production, and inhibition of angiogenesis. Plus, it was shown that OA effectively suppressed the generation of ROS generated by LL-37, as well as the subsequent activation of NF-κB signaling pathway. To explore further, we found that OA inhibited LL-37-induced ROS production via SIRT3-SOD2 signaling pathway in keratinocytes. Based on the aforementioned evidence, it can be inferred that OA exhibits a mitigating effect on the inflammatory response in rosacea by modulating the SIRT3-SOD2-NF-κB signaling pathway.

Improvement in Cutaneous Conditions Can Benefit Some Health Conditions in the Elderly

As we are aging, a number of cutaneous and extracutaneous disorders will be developed. Although the pathogenesis of these aging-associated disorders is not clear yet, abnormalities in the skin are linked to some aging-associated disorders at least to some extent. Inflammatory dermatoses such as psoriasis and atopic dermatitis predispose to the development of cardiovascular diseases, obesity and type 2 diabetes. In addition, both chronologically aged skin and individuals with some aging-associated systemic conditions display altered epidermal function, such as reduced stratum corneum hydration levels, which can provoke cutaneous inflammation. Because aged skin exhibits higher expression levels of inflammatory cytokines, which play a pathogenic role in a variety of aging-associated health condition, the association of the skin with some aging-associated disorders is likely mediated by inflammation. This postulation is supported by the evidence that improvement in either epidermal function or inflammatory dermatoses can mitigate some aging-associated disorders such as mild cognitive impairment and insulin sensitivity. This perspective discusses the association of the skin with aging-associated disorders and highlights the potential of improvement in cutaneous conditions in the management of some health conditions in the elderly.