The role of altered cutaneous immune responses in the induction and persistence of rosacea

Mechanisms and Recent Advances of Small-Molecule Therapeutics in Rosacea Treatment

Rosacea is a common dermatological disease, and the complexity of its etiology and pathogenesis makes conventional treatment of rosacea difficult. Small-molecule drugs are a new option for the treatment of rosacea. Based on its good efficacy, convenience of use, affordable price and other advantages, more and more small-molecule drugs are used in the treatment and management of rosacea, involving a variety of molecular pathways, including JAK/STAT signaling pathway, TRPV, TLR2-KLK5-LL37 and mTOR pathways, Th1/Th17-IL17, PED-4, AhR and MRGPRX2. However, the specific treatment mechanism and research progress have not been systematically elucidated. This review summarizes the latest advances in small molecules targeting key inflammatory pathways in rosacea, provides new ideas for the treatment of rosacea and new directions for the clinical management of rosacea. In addition, we need to pay attention to individual differences in patients, the side effects of drugs and formulations. Therefore, further research on small-molecule drugs for the treatment of rosacea is very necessary.

A comparative exploration of immunohistochemical markers in patients with papulopustular rosacea undergoing treatment with oral isotretinoin versus doxycycline

BACKGROUND

Rosacea is a chronic inflammatory disease, and doxycycline is a widely recommended treatment for it due to its anti-inflammatory action. Oral isotretinoin reduces sebaceous gland activity and modulates toll-like receptors, reducing inflammation. Our aim was to investigate the effect of these two drugs on the expression of cutaneous immunohistochemical biomarkers related to etiopathogenic factors involved in rosacea.

METHODS

We conducted a randomized, comparative, and evaluator-blinded trial, including 40 participants with moderate and severe papulopustular and ocular rosacea. Participants were treated with doxycycline (DOXY) 100 mg or isotretinoin (ISO) 0.3 mg/kg daily. Immunohistochemistry at baseline and after 4 months was used to demonstrate the expression of the biomarker on the affected skin.

RESULTS

The following changes were detected: a reduction in the vessel count after using VEGF with DOXY (P = 0.010); a decrease in VEGF intensity with ISO (P < 0.001) and DOXY (P = 0.020); a reduction of nitric oxide synthase enzyme with both drugs in the inflammatory infiltrate (ISO P < 0.001; DOXY P = 0.003); however, only with ISO was there a significant (P = 0.030) decrease at the level of the sebaceous glands, indicating a reduction of nitric oxide synthesis; a reduction of TRPV-1 expression at the level of the sebaceous glands was observed only with DOXY (P = 0.041); a decrease of cathelicidin LL37 expression, a key antimicrobial peptide in the etiopathogenesis of rosacea, was noted with both drugs, although at the level of sebaceous glands, only with DOXY (P = 0.007).

CONCLUSIONS

Oral isotretinoin and doxycycline have modified the expression of cutaneous biomarkers related to rosacea etiopathogenesis, demonstrating their role in controlling inflammatory and vascular processes.

Probiotics suppress LL37 generated rosacea-like skin inflammation by modulating the TLR2/MyD88/NF-κB signaling pathway

Rosacea, a chronic inflammatory dermatological condition, is characterized by facial erythema and pustules. Recent investigations have delved into the interplay between the gut microbiota and rosacea pathogenesis, unveiling promising avenues for therapeutic intervention. In this study, we screened and isolated strains Ligilactobacillus salivarius 23-006 and Lacticaseibacillus paracasei 23-008 from the feces of healthy volunteers and evaluated the intervention effects of probiotics on rosacea by constructing an LL37 induced rosacea-like mouse model. Our results showed that both L. salivarius 23-006 and L. paracasei 23-008 were probiotic strains with favourable properties. In specific, we observed that both L. salivarius 23-006 and L. paracasei 23-008 alleviated skin lesions, reduced skin inflammatory infiltrates, and decreased the expression of inflammatory factors in mice, with the combination of L. salivarius 23-006 and L. paracasei 23-008 having the most significant effect. Moreover, the combination of strains reduced the expression of cathelicidin LL37 and rosacea-associated factors by inhibiting the TLR2/MyD88/NF-κB pathway. The 16S rRNA analysis showed that the combination enhanced the intestinal barrier, restored intestinal microbiota homeostasis, and up-regulated the abundance of Lactobacillus while down-regulating the abundance of Coprococcus and Oscillospira. We also explored the effects of postbiotics of L. salivarius 23-006 and L. paracasei 23-008 on rosacea. While postbiotics could also ameliorate the rosacea-like phenotype in mice via the TLR2/MyD88/NF-κB pathway, the effects were not as pronounced as those observed with probiotic treatment. However, the postbiotics still enhanced the intestinal barrier, up-regulated the Lactobacillus abundance, and modulated the intestinal microbiota. In conclusion, our study revealed that L. salivarius 23-006 and L. paracasei 23-008 improved rosacea by regulating the TLR2/MyD88/NF-κB pathway and intestinal microbiota, providing a theoretical basis for the treatment of rosacea.

Therapeutic strategies focusing on immune dysregulation and neuroinflammation in rosacea

Rosacea is a complex inflammatory condition characterized by papulopustular lesions and erythema on the central face for which there is no cure. The development of rosacea is influenced by both external triggers and genetics, but the common pathophysiology is overactivation of the immune system. Here, we review the current data on proinflammatory cytokines and dysregulation of the neurovascular system as targetable components of rosacea. Amelioration of cutaneous and gastrointestinal dysbiosis and other external factors impacts the immune state and has been observed to improve rosacea. While multiple treatments exist, many patients do not achieve their goals for rosacea control and highlights an unmet need for dermatologic care. Current interventions encompass topical/oral drugs, light devices, and avoidance of triggers management. Additional understanding of the underlying pathogenesis may help us develop novel targeted therapeutic strategies to improve rosacea.

LncRNA NEAT1 targets miR-125/ADAM9 mediated NF-κB pathway in inflammatory response of rosacea

OBJECTIVE

To investigate the role of NEAT1 targeted regulation of miR-125/ADAM9 mediated NF-κB pathway in inflammatory response in rosacea.

METHOD

HaCaT cell rosacea phenotype was induced by LL37. The connection targeted by NEAT1 and miR-125a-5p was confirmed by Double-Luciferase report analysis. qPCR was employed to assess the levels of expression for NEAT1, miR-125a-5p, and ADAM9 genes. The levels of expression for ADAM9/TLR2/NF-κB P65 pathway proteins in each batch of cells were determined by Western blotting. The levels of expression for inflammatory factors, including TNF-α, IL-1β, IL-6, and IL-18, were measured through ELISA experimentation.

RESULTS

LL37 could successfully induce HaCaT cells to exhibit rosacea phenotype. The luciferase report experiment confirmed that NEAT1 could target and bind miR-125a-5p and inhibit its expression. ADAM9 exhibited increased expression in LL37-induced HaCaT cells, showing a positive association with NEAT1 expression and inverse relationship with miR-125a-5p activation. LL37 treatment promoted the expression of ADAM9/TLR2/NF-κB P65 pathway proteins. Silencing ADAM9 can inhibit the inflammatory signaling pathway and reduce the level of TNF-α, IL-1β, IL-6, and IL-18 in HaCaT cells.

CONCLUSION

NEAT1 can suppress the production of miR-125a-5p and activate the TLR2/NF-κB inflammatory pathway mediated by ADAM9, thereby promoting the inflammatory response in rosacea.

Toll-like receptors: their roles in pathomechanisms of atopic dermatitis

The skin functions as a physical barrier and represents the first line of the innate immune system. There is increasing evidence that toll-like receptors (TLRs) are involved in the pathomechanisms of not only infectious diseases, but also non-infectious inflammatory diseases. Interestingly, it has been demonstrated that TLRs recognize both exogenous threats, e.g. bacteria and viruses, and endogenous danger signals related to inflammation, cell necrosis, or tissue damage. Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disease, which is associated with impaired skin barrier function, increased skin irritability to non-specific stimuli, and percutaneous sensitization. The impairment of skin barrier function in AD allows various stimuli, such as potential allergens and pathogens, to penetrate the skin and activate the innate immune system, including TLR signaling, which can lead to the development of adaptive immune reactions. In this review, I summarize the current understanding of the roles of TLR signaling in the pathogenesis of AD, with special emphasis on skin barrier function and inflammation.

Dietary supplementation of n-3 PUFAs ameliorates LL37-induced rosacea-like skin inflammation via inhibition of TLR2/MyD88/NF-κB pathway

Rosacea is a facial chronic inflammatory skin disease with dysfunction of immune and neurovascular system and treatments for rosacea are challenging. N-3 polyunsaturated fatty acids (PUFAs), one of essential fatty acids, are needed for health maintenance and exert anti-inflammation and immunomodulatory effects in a series of cutaneous diseases such as atopic dermatitis and photoaging through dietary supplementation. However, the role of n-3 PUFAs on rosacea remains to be elucidated. In this study, KEGG enrichment analysis and GO analysis indicated that the biological process and signaling pathways, including chemokine signaling pathway, regulated by n-3 PUFAs highly overlapped with those in the pathogenic biological process of rosacea, especially the erythema telangiectasia type. Next, mice were randomized to fed with a customized n-3 PUFAs diet. We showed that n-3 PUFAs ameliorated skin erythema, inhibited dermal inflammatory cell infiltration (mast cells, neutrophils, and CD4 +T cells) and suppressed elevated pro-inflammatory cytokines in LL37-induced rosacea-like mice. Besides, n-3 PUFAs were also verified to repress angiogenesis in LL37-induced mice skin. Further investigation revealed that n-3 PUFAs attenuated LL37-induced inflammation via TLR2/ MyD88/ NF-κB pathway both in mice and in keratinocytes. In conclusion, our findings underscore that dietary supplementation of n-3 PUFAs have the potential to become an efficient and safe clinical therapeutic candidate for rosacea.

Thalidomide Attenuates Skin Lesions and Inflammation in Rosacea-Like Mice Induced by Long-Term Exposure of LL-37

Purpose

Most of the existing studies focus on the early inflammation of rosacea, with few interventions on the later development of fibrosis and the relationship between thalidomide and rosacea. The purpose of this study was to construct a long-term induction model and explore the effects of thalidomide on the later stage of inflammation and early stage of fibrosis in rosacea.

Patients and Methods

BALB/c male mice were randomly divided into four groups: control group, control plus thalidomide group, LL-37 group and LL-37 plus thalidomide group, Intradermal and intraperitoneal injections were given. After repeated induction, skin changes were recorded by taking photos. The animals were sacrificed, the back skin was used for HE staining and VG staining to detect histomorphological characteristics. Immunofluorescence staining and Western blot were used to detect the expression of inflammatory and fibrosis-related factors.

Results

The results were compared with the early stage of the model, wherein the skin inflammation of the 20-day mice was more obvious with a trend of fibrosis. Compared with the control group, histopathological examination showed that the inflammatory cell infiltration in the LL-37 group was significantly increased, and the skin was thickened with collagen deposition. LL-37 induction significantly increased the expression of inflammatory markers (eg, TNF-α and IL-1β) and fibrotic markers (eg, COL1, α-SMA, vimentin and N-Cadherin). Intervention with thalidomide significantly reduced erythema, inflammatory cell infiltration, collagen deposition, and down-regulate the expression of inflammation and fibrosis related factors in rosacea mice.

Conclusion

The long-term continuous induction of LL-37 in mice could simulate the occurrence and development of rosacea, and thalidomide could ameliorate the rosacea induced by long-term exposure to LL-37 by regulating inflammatory infiltration, collagen deposition and fibrosis-related processes.

Current research and clinical trends in rosacea pathogenesis

BACKGROUND

Rosacea is a common and complex chronic inflammatory skin disorder, the pathophysiology and etiology of which remain unclear. Recently, significant new insights into rosacea pathogenesis have enriched and reshaped our understanding of the disorder. A systematic analysis based on current studies will facilitate further research on rosacea pathogenesis.

OBJECTIVE

To establish an international core outcome and knowledge system of rosacea pathogenesis and develop a challenge, trend and hot spot analysis set for research and clinical studies on rosacea using bibliometric analysis and data mining.

METHODS

A search of the WoS, and PubMed, MEDLINE, Embase and Cochrane collaboration databases was conducted to perform visual bibliometric and data analysis.

RESULTS

A total of 2,654 studies were used for the visualization and 302 of the 6,769 outcomes for data analysis. It reveals an increased trend line in the field of rosacea, in which its fast-growing pathogenesis attracted attention closely related to risk, comorbidity and therapeutic strategies. The rosacea pathogenesis has undergone the great development on immunology, microorganisms, genes, skin barriers and neurogenetics. The major of studies have focused on immune and microorganisms. And keyword visualization and data analyses demonstrated the cross-talk between cells or each aspect of pathogenesis, such as gene-gene or gene-environment interactions, and neurological mechanisms associated with the rosacea phenotype warrant further research.

LIMITATIONS

Inherent limitations of bibliometrics; and reliance on research and retrospective studies.

CONCLUSIONS

The understanding of rosacea's pathogenesis has been significantly enhanced with the improved technology and multidisciplinary integration, but high-quality, strong evidence in favor of genomic and neurogenic requires further research combined with a better understanding of risks and comorbidities to guide clinical practice.

Perspectives on rosacea patient characteristics and quality of life using baseline data from a phase 3 clinical study conducted in Japan

There is a lack of contemporary data on rosacea originating in Japan. Using baseline data from a randomized, phase 3 study of 130 Japanese patients with rosacea treated with metronidazole gel (0.75%) or vehicle, the authors evaluated demographic and clinical characteristics, pretreatment quality of life, and exacerbating factors. In line with global data, most patients were women (82.3%; 107/130) and aged between 30 and 50 years (60.7%; 79/130). Patient-reported quality of life scores indicated that rosacea had an impact similar to that of other debilitating and disfiguring skin conditions (such as psoriasis), particularly in terms of the emotional burden. Anxiety or depression was reported by 30% of patients (39/130), with 6.9% (9/130) reporting moderate levels and 0.8% (1/130) reporting severe levels. The top five exacerbating factors reported to trigger worsening of rosacea were temperature changes, sun exposure, hot weather, seasonal variation, and heavy exercise. In addition, pollen exposure and menstruation were noted as triggers of rosacea symptoms; these are novel findings that require further investigation to fully understand the implications for patients and treatment. Rosacea is likely to be underdiagnosed and undertreated in Japan because of the current lack of consensus guidelines and standardized therapy. The authors anticipate that the results of this analysis will provide much needed information to help improve diagnosis and facilitate the management of rosacea in patients.

Characterization of rosacea in Chinese: An analysis of 254 cases

BACKGROUND

Rosacea is a common chronic inflammatory dermatosis with uncertainty of etiology. Although clinical features and risk factors of the disease in Caucasians have been reported, this information in Chinese is largely unavailable.

AIMS

To analyze the clinical features and associated risk factors of rosacea in Chinese.

METHODS

A questionnaire was given to outpatients with rosacea who visited the dermatology department of the first affiliated hospital of Kunming Medical University from June 2018 to March 2019. Analyses included demographic characteristics of subjects, clinical characteristics, and risk factors of rosacea.

RESULTS

A total of 254 outpatients completed the questionnaire. The ratio of female to male was 5.68:1.00. The mean age at onset was 31.18 ± 10.23 years. Erythematotelangiectatic subtype accounted for 51.60%, while 39% of the subjects were of papulopustular subtype. The rest were phymatous type (9.40%). Subjects with flushing, persistent facial erythema, and telangiectasia accounted for 91.73%, 90.55%, and 83.07%, respectively. One hundred and thirteen subjects (44.49%) had papules or pustules, and 24 subjects (9.40%) were with phymatous changes. The most commonly involved sites were the cheeks (93.31%), followed by the nose (82.68%), the perioral area (61.42%), and the forehead (51.97%). The clinical symptoms included burning (93.70%), dryness (90.55%), and itching (75.59%). The main risk factors were sun exposure (90.94%), temperature change (87.40%), etc. Fifty-one (20.08%) patients had comorbidities.

CONCLUSIONS

Rosacea mainly affects young females. The common signs and symptoms include flushing, persistent facial erythema, and burning. Sun exposure and temperature changes are the common risk factors. Patients can have comorbidities of systemic disorders.

Rosacea with persistent facial erythema and high Demodex density effectively treated with topical ivermectin alone or combined with oral carvedilol

Topical ivermectin is effective in treating papulopustular rosacea, but its effect on persistent facial erythema of rosacea with high Demodex densities has not been well documented. We retrospectively reviewed 39 rosacea patients with persistent facial erythema and high Demodex densities. Clinician's erythema assessment (CEA) and Demodex density were evaluated before and after topical ivermectin alone or combined with oral carvedilol. Three patients (all with papulopustular rosacea, in ivermectin group) dropped out due to early ivermectin-induced local flare of rosacea. In the remaining patients (ivermectin group n = 14; ivermectin-carvedilol group n = 22), the CEA grade and Demodex density were significantly reduced, both P < .01. There was no statistically significant difference between the two groups in CEA before and after treatment (P = .07 and P = .23, respectively), and in Demodex density (P = .82 and .10, respectively). Both regimens markedly improved the persistent facial erythema with response being excellent in 26 of 36 patients (72%), good in 2, fair in 4 and none in 4. There was a correlation between the reduction of CEA and Demodex density after treatment (rho = 0.50, P = .002). The results showed that topical ivermectin was effective in reducing persistent facial erythema of rosacea with Demodex overgrowth.

Long non-coding RNA NEAT1 functions as a competing endogenous RNA to regulate S100A9 expression by sponging miR-196a-5p in rosacea

BACKGROUND

Rosacea is a complex, chronic, and recurrent dermatologic condition that adversely affects quality of life and self-esteem. However, clinical relevance and molecular mechanisms underlying NEAT1 influence in rosacea remain unclear.

OBJECTIVE

The present study aims to investigate the dynamics and influences of lncRNAs, miRNAs, and mRNAs in rosacea patients, and to explore the impacts of NEAT1 treatments on miR-196a-5p and S100A9 expression in LL37-treated HaCaT cells.

METHODS

RNA-sequencing of skin tissues from rosacea patients and integrative analyses facilitated comprehensive exploration of lncRNA, mRNA, and miRNA networks. We identified differentially expressed lncRNAs in paired rosacea afflicted and non-lesioned tissues by hub lncRNAs in the ceRNA network. The role of NEAT1 in LL37-treated HaCaT cells was identified by in vitro experiments.

RESULTS

There were 237 lncRNAs, 38 miRNAs, and 1784 mRNAs in lesioned skin compared to non-lesioned skin in six rosacea patients. NEAT1 was upregulated in rosacea skin and in LL37-treated HaCaT cells. Moreover, inflammatory damage was able to be reduced in vitro after knockdown of NEAT1. Finally, NEAT1 was able to directly interact with miR-196a-5p, and downregulating miR-196a-5p was efficient in reversing the influence of NEAT1 siRNA on S100A9.

CONCLUSION

We have completed the first genome-wide lncRNA profiling of paired lesioned and non-lesioned samples from rosacea afflicted patients. The NEAT1/miR-196a-5p/S100A9 axis may have played an important role in the dynamics underlying inflammatory responses of rosacea. NEAT1 may have functioned as a competing endogenous RNA which regulated inflammatory responses in rosacea by sponging miR-196a-5p and upregulating S100A9 expression.

Rosacea and the Microbiome: A Systematic Review

Rosacea, a chronic inflammatory skin disease characterized by recurrent episodes of facial flushing, erythema, pustules, and telangiectasia, largely affects fair-skinned women over 30 years of age. Although a long-recognized entity, the exact pathophysiology of this disease is still debated. Current theories highlight the role of the cutaneous microbiome and its associated inflammatory effects in rosacea's pathogenesis. However, microbiological reverberations are not limited to the skin, as recent studies have described the potential cutaneous effects of alterations in the gastrointestinal (GI) microbiome. Associations with additional GI pathologies, including small intestinal bacterial overgrowth (SIBO), irritable bowel syndrome (IBS), and inflammatory bowel disease (IBD), have been investigated, as well as Helicobacter pylori infection. In an attempt to better understand and characterize these relationships, as well as current treatment options, we conducted a systematic review of the literature in PubMed, Cochrane, and Embase from their inception to August 6, 2020. We have synthesized the literature findings within three sections of this manuscript: the cutaneous microbiome, the gut microbiome, and therapeutic strategies. Future studies should focus on specific mechanisms linking GI pathology with rosacea manifestations and the role of enteral drugs in mitigating cutaneous symptoms.

Characterization of Pro- and Anti-Inflammatory Tissue Factors in Rosacea: A Pilot study

Rosacea is a chronic inflammatory skin disease mainly affecting the facial skin. Our aim was to determine the appearance of pro- and anti- inflammatory cytokines in rosacea-affected facial tissue. Materials and Methods: Rosacea tissue were obtained from eight patients (aged 35 to 50 years). The control group (CG) included four facial skin samples (49 to 70 years). Routine staining and immunohistochemistry for IL-1, IL-10, LL-37, HBD-2, and HBD-4 proceeded. Results: Inflammation was observed in all the rosacea samples. A statistically significant difference was seen between epithelial HBD-2 positive cells in comparison to the control. There was a strong positive correlation between HBD-4 in the epithelium and HBD-4 in the connective tissue, IL-10 in the epithelium and IL-1 in the connective tissue, and IL-1 in the epithelium and IL-10 in the connective tissue. Conclusion: Increased levels of IL-10 and decreased levels of IL-1 show the balance between anti- and pro-inflammatory tissue responses. A significant amount of HBD-2 in the epithelium proves its important role in the local immune response of rosacea-affected tissue. The last effect seems to be intensified by the elevated level of LL-37 in the epithelium.

Demodex: a skin resident in man and his best friend

Demodex mites are microscopic arachnids found in the normal skin of many mammals. In humans, it is well established that Demodex mite density is higher in patients with the skin condition rosacea, and treatment with acaricidal agents is effective in resolving symptoms. However, pathophysiology of rosacea is complex and multifactorial. In dogs, demodicosis is a significant veterinary issue, particularly the generalized form of the disease which can be fatal if untreated. In each species, clinical and molecular studies have shown that the host's immunological interactions with Demodex mites are an important, but not fully understood, aspect of how Demodex can live in the skin either as a harmless commensal organism or as a pathogenic agent. This review outlines the role of Demodex mites in humans and dogs, considering morphology, prevalence, symptoms, diagnosis, histology treatment and pathogenesis.

Intense Pulsed Light Therapy In The Treatment Of Meibomian Gland Dysfunction: Current Perspectives

Dry eye disease (DED) is among the most common condition encountered during ophthalmic practice, reducing patient's quality of life and work productivity. Most of DED cases have an evaporative component originated from a meibomian gland dysfunction (MGD). Conventional treatments such as tear substitute, warm compresses, topical anti-inflammatory agents and/or antibiotics often are not able to provide a complete and long-term relief of symptoms and signs. Intense pulsed light (IPL) has been widely used in the field of dermatology to treat various skin conditions, and it has been recently introduced in the ophthalmic practice for the management of DED due to MGD. To date, several clinical studies showed positive results of IPL as adjuvant therapy for DED in terms of both safety and efficacy. The treatment is usually well accepted among patients for its non-invasive nature; very rare are the major adverse reactions. Moreover, results can be maintained over time with periodic sessions of IPL. This review summarizes the clinical outcomes of IPL therapy in MGD patients pointing out its potential role in the therapeutic algorithm of the disease. Further clinical investigations are desirable to identify factors able to predict the positive outcomes of the procedure and therefore to select in advance those patients who best benefit from IPL therapy.

Analysis of the effect of temperature on protein abundance in Demodex-associated Bacillus oleronius

A potential role for bacteria in the induction of rosacea has been suggested. The aim of this work was to characterise the effect of temperature on the production of immunostimulatory proteins by Bacillus oleronius-a bacterium to which rosacea patients show sera reactivity and which was originally isolated from a Demodex mite from a rosacea patient. The affected skin of rosacea patients is at a higher temperature than unaffected skin, and it was postulated that this might alter the protein expression pattern of B. oleronius. B. oleronius growth was reduced at 37°C compared to 30°C but resulted in increased expression of the immune-reactive 62kDa protein (1.65 fold [P < 0.05]). Proteomic analysis revealed increased abundance of a wide range of proteins involved in the stress response (e.g. stress proteins [21.7-fold increase], phosphocarrier protein HPr [438.5-fold increase], 60 kDa chaperonin [12.6-fold increase]). Proteins decreased in abundance after growth at 37°C included ferredoxin (325-fold decrease) and peptidase (244-fold decrease). This work indicates that the increased skin temperature of rosacea patients may alter the growth and protein production pattern of B. oleronius and lead to the greater production of immuo-stimulatory proteins.

ROSACEA IS ASSOCIATED WITH THYROID AUTOIMMUNITY: A CASE CONTROL STUDY

BACKGROUND AND AIMS

There are numerous intrinsic and extrinsic factors associated with the pathophysiology of rosacea, including immune dysregulation. The aim of this study is to determine the relationship between rosacea and thyroid autoimmunity.

METHODS

Seventy-two patients with rosacea and 62 rosacea-free control subjects were included in the study. Serum free triiodothyronine (fT3), free thyroxine (fT4), thyrotropin releasing hormone (TSH), antithyroidperoxidase antibody (ATPO), antithyroglobulin (anti-Tg), prolactin, dehydroepiandrosterone sulfate (DHEAS), basal cortisol, serum CRP concentrations and erythrocyte sedimentation rate were measured.

RESULTS

The number of the cases with high levels of CRP, anti-M and prolactin in rosacea group were significantly higher than the controls (p<0.05), there was no significant difference according to other parameters in both groups (p>0.05). There was no significant difference according to the presence of a thyroid disease in both groups (p>0.05). The decrease in the CRP parameter in patients with the disease duration of 1-5 years was found to be statistically significant (βCRP=-0.251, pCRP<0.05). There was no statistically significant difference according to disease severity or disease duration (p>0.05).

CONCLUSIONS

Rosacea may be associated with high thyroid autoantibodies, prolactin and CRP levels, in which immune-endocrine interactions are important.

Rosacea Pathogenesis

Rosacea is a chronic inflammatory skin disorder that is not fully understood but involves the complex interplay of genetic factors, immune dysregulation, neurovascular dysregulation, presence of microorganisms, and environmental factors. Increased activation of the immune system occurs through multiple stimuli, including increased levels of cathelicidin and kallikrein 5, Toll-like receptor 2, matrix metalloproteinases, and mast cells within the skin. Their effects are enhanced by the presence of microorganisms and external triggers, such as UV radiation.

Human Skin Permeation Studies with PPARγ Agonist to Improve Its Permeability and Efficacy in Inflammatory Processes

Rosacea is the most common inflammatory skin disease. It is characterized by erythema, inflammatory papules and pustules, visible blood vessels, and telangiectasia. The current treatment has limitations and unsatisfactory results. Pioglitazone (PGZ) is an agonist of peroxisome proliferator-activated receptors (PPARs), a nuclear receptor that regulates important cellular functions, including inflammatory responses. The purpose of this study was to evaluate the permeation of PGZ with a selection of penetration enhancers and to analyze its effectiveness for treating rosacea. The high-performance liquid chromatography (HPLC) method was validated for the quantitative determination of PGZ. Ex vivo permeation experiments were realized in Franz diffusion cells using human skin, in which PGZ with different penetration enhancers were assayed. The results showed that the limonene was the most effective penetration enhancer that promotes the permeation of PGZ through the skin. The cytotoxicity studies and the Draize test detected cell viability and the absence of skin irritation, respectively. The determination of the skin color using a skin colorimetric probe and the results of histopathological studies confirmed the ability of PGZ-limonene to reduce erythema and vasodilation. This study suggests new pharmacological indications of PGZ and its possible application in the treatment of skin diseases, namely rosacea.

Dual anti-inflammatory and anti-parasitic action of topical ivermectin 1% in papulopustular rosacea

BACKGROUND

Recently, therapy of rosacea with inflammatory lesions (papulopustular) has improved substantially with the approval of topical ivermectin 1% cream. It is assumed to have a dual mode of action with anti-inflammatory capacities and anti-parasitic effects against Demodex, which however has not yet been demonstrated in vivo.

AIM

To find scientific rationale for the dual anti-inflammatory and anti-parasitic mode of action of topical ivermectin 1% cream in patients with rosacea.

METHODS

A monocentric pilot study was performed including 20 caucasion patients with moderate to severe rosacea, as assessed by investigator global assessment (IGA score ≥3) and a Demodex density ≥15/cm² . Patients were treated with topical ivermectin 1% cream once daily (Soolantra^® ) for ≥12 weeks. The density of Demodex mites was assessed with skin surface biopsies. Expression of inflammatory and immune markers was evaluated with RT-PCR and by immunofluorescence staining.

RESULTS

The mean density of mites was significantly decreased at week 6 and week 12 (P < 0.001). The gene expression levels of IL-8, LL-37, HBD3, TLR4 and TNF-α were downregulated at both time points. Reductions in gene expression were significant for LL-37, HBD3 and TNF-α at both follow-up time points and at week 12 for TLR4 (all P < 0.05). Reduced LL-37 expression (P < 0.05) and IL-8 expression were confirmed on the protein level by immunofluorescence staining. All patients improved clinically, and 16 of 20 patients reached therapeutic success defined as IGA score ≤1.

CONCLUSION

Topical ivermectin 1% cream acts by a dual, anti-inflammatory and anti-parasitic mode of action against rosacea by killing Demodex spp. in vivo, in addition to significantly improving clinical signs and symptoms in the skin.

Role of Demodex mite infestation in rosacea: A systematic review and meta-analysis

BACKGROUND

The reported prevalence and degrees of Demodex mite infestation in rosacea vary widely.

OBJECTIVE

We sought to conduct an evidence-based meta-analysis of the prevalence and degrees of Demodex mite infestation in patients with rosacea.

METHODS

Systematic literature review and meta-analysis were conducted. Odds ratios for prevalence of infestation and standardized mean difference (SMD) for Demodex density in patients with rosacea were pooled. Subgroup analysis for type of rosacea, control group, and sampling and examination methods were also performed.

RESULTS

Twenty-three case-control studies included 1513 patients with rosacea. Compared with the control patients, patients with rosacea were more likely to be infested by Demodex mites [odds ratio, 9.039; 95% confidence interval (CI), 4.827-16.925] and had significantly higher Demodex density (SMD, 1.617; 95% CI, 1.090-2.145). Both erythematotelangiectatic rosacea (SMD, 2.686; 95% CI, 1.256-4.116) and papulopustular rosacea (SMD, 2.804; 95% CI, 1.464-4.145) had significantly higher Demodex density than did healthy control patients.

LIMITATIONS

Interstudy variability was high, and a causal relationship could not be established by case-control studies.

CONCLUSIONS

Patients with rosacea had significantly higher prevalence and degrees of Demodex mite infestation than did control patients. Demodex mites may play a role in both erythematotelangiectatic rosacea and papulopustular rosacea.

An observational descriptive survey of rosacea in the Chinese population: clinical features based on the affected locations

BACKGROUND

There is currently no study that has evaluated the differences in epidemiological and clinical characteristics among rosacea patients according to different facial sites.

METHODS

Clinical and demographic data were obtained from 586 rosacea patients. The patients were divided into four groups based on the main sites involved with the rosacea lesions (full-face, cheeks, nose, or perioral involvement). Clinical signs were measured through self-reported, dermatologist-evaluated grading of symptoms, and physiological indicators of epidermal barrier function.

RESULTS

There were 471 (80.4%), 49 (8.4%), 52 (8.9%), and 14 (2.4%) cases in the full-face, cheek, nasal and perioral groups, respectively. Compared with the healthy control, the full-face group had lower water content and higher transepidermal water loss (TEWL) in the cheeks, and chin; the perioral group had lower water content and higher TEWL in the chin; while the nasal group had the normal water content and TEWL. Compared with the full-face group, the nasal group had more severe phymatous changes, less severe self-reported and dermatologist-evaluated grading of symptoms. All the patients in the perioral or the nasal group had their first rosacea lesions start and remain at the chin or on the nose. In the full-face group, 55.8% of patients had their lesions start with the full face, 40.1% on the cheek, and the rest (4.1%) on the nose.

CONCLUSION

Significant differences in clinical features were observed among rosacea patients with lesions at four different sites. The lesion localization of each group was relatively stable and barely transferred to other locations.

Intense pulsed light for evaporative dry eye disease

There is a clear association between dry eye disease (DED) and skin inflammatory diseases occurring in close proximity to the eyelids, such as facial skin rosacea. Intense pulsed light (IPL) is widely accepted as a treatment for skin rosacea. A number of recent studies demonstrated that, in patients suffering from meibomian gland dysfunction (MGD), IPL therapy also reduces signs and symptoms of DED. Despite these encouraging results, in the context of DED and MGD, the mechanisms of action of IPL are not well understood. The purpose of this review was to raise the potential mechanisms of action and to discuss their plausibility.