Tetracycline suppresses ATP gamma S-induced CXCL8 and CXCL1 production by the human dermal microvascular endothelial cell-1 (HMEC-1) cell line and primary human dermal microvascular endothelial cells

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.

Systemic Comorbidities in Korean Patients with Rosacea: Results from a Multi-Institutional Case-Control Study

Recent evidence links rosacea to systemic disease, but there are not enough methodologic studies addressing this association in Asians. Our aim was to identify rosacea comorbidities in Koreans and establish a reference database. A multi-center, case-control study was performed where a total of 12,936 rosacea patients and 12,936 age- and sex-matched control subjects were identified from 2007 to 2018. Logistic regression was performed to find significant association between rosacea and Sjögren syndrome (odds ratio [OR] 2.05; 95% confidence interval, 1.40–3.00), systemic sclerosis (OR 6.56; 95% CI, 1.50–28.7), rheumatoid arthritis (OR 1.72; 95% CI, 1.50–1.98), ankylosing spondylitis (OR 2.32; 95% CI, 1.42–3.84), autoimmune thyroiditis (OR 1.96; 95% CI, 1.40–2.73), alopecia areata (OR 1.77; 95% CI, 1.27–2.45), vitiligo (OR 1.90; 95% CI, 1.30–2.77), lung cancer (OR 1.54; 95% CI, 1.06–2.21), hepatobiliary cancer (OR 1.38; 95% CI, 1.06–1.77), alcohol abuse (OR 1.59; 95% CI, 1.05–2.39), diabetes mellitus (OR 1.11; 95% 1.02–1.19), obesity (OR 1.72; 95% CI, 1.22–2.41), allergic rhinitis (OR 1.65; 95% CI, 1.54–1.76), allergic conjunctivitis (OR 1.57; 95% CI, 1.27–1.94), chronic rhinosinusitis (OR 1.28; 95% CI, 1.14–1.42), herpes infection (OR 1.69; 95% CI, 1.53–1.86), and human papillomavirus infection (OR 2.50; 95% CI, 2.06–3.02). Higher odds for Sjogren syndrome, systemic sclerosis, ankylosing spondylitis, thyroiditis, vitiligo, hepatobiliary cancer, and obesity was exclusive in female subjects with rosacea, whereas increased prevalence of alopecia areata and alcohol abuse was confined to men. Only those who were 50 years and older exhibited higher odds for vitiligo, lung cancer, and gastroesophageal reflux disease while individuals younger than 50 were exclusively associated with hepatobiliary cancer, allergic conjunctivitis, and irritable bowel syndrome. Our study suggests that Koreans with rosacea are more likely to experience systemic comorbidity. Clinicians should acknowledge these interrelations and employ comprehensive care with an individual-based approach.

Analysis of Potential Genes and Pathways Involved in the Pathogenesis of Acne by Bioinformatics

Acne is the eighth most frequent disease worldwide. Inflammatory response runs through all stages of acne. It is complicated and is involved in innate and adaptive immunity. This study aimed to explore the candidate genes and their relative signaling pathways in inflammatory acne using data mining analysis. Microarray data GSE6475 and GSE53795, including 18 acne lesion tissues and 18 matched normal skin tissues, were obtained. Differentially expressed genes (DEGs) were filtered and subjected to functional and pathway enrichment analyses. Protein-protein interaction (PPI) network and module analyses were also performed based on the DEGs. In this work, 154 common DEGs, including 145 upregulated and 9 downregulated, were obtained from two microarray profiles. Gene Ontology and pathway enrichment of DEGs were clustered using significant enrichment analysis. A PPI network containing 110 nodes/DEGs was constructed, and 31 hub genes were obtained. Four modules in the PPI network, which mainly participated in chemokine signaling pathway, cytokine-cytokine receptor interaction, and Fc gamma R-mediated phagocytosis, were extracted. In conclusion, aberrant DEGs and pathways involved in acne pathogenesis were identified using bioinformatic analysis. The DEGs included FPR2, ITGB2, CXCL8, C3AR1, CXCL1, FCER1G, LILRB2, PTPRC, SAA1, CCR2, ICAM1, and FPR1, and the pathways included chemokine signaling pathway, cytokine-cytokine receptor interaction, and Fc gamma R-mediated phagocytosis. This study could serve as a basis for further understanding the pathogenesis and potential therapeutic targets of inflammatory acne.

Target site pharmacokinetics of doxycycline for rosacea in healthy volunteers is independent of the food effect

Aims

Doxycycline (DFD‐09) oral capsules 40 mg are approved for the treatment of inflammatory lesions of rosacea. Unlike the food‐induced lowering of doxycycline's peak plasma concentration (C_max), its exposure under fed conditions in the skin, the drug's target site for rosacea, is unknown. The present study explored the effect of food on the dermal pharmacokinetics of doxycycline.

Methods

The pharmacokinetics of doxycycline in the dermal interstitial fluid (d‐ISF) and plasma of healthy volunteers were assessed in parallel groups under fed (n = 6) and fasting (n = 6) conditions during a 14‐day once‐daily treatment course with doxycycline oral capsules 40 mg (DFD‐09). Sampling of d‐ISF and plasma was performed on days 1, 10 (fasting group d‐ISF only) and 14.

Results

Twelve subjects were randomized, and 11 analysed. No causally drug‐related adverse events occurred. Dermal doxycycline exposures (C_max and area under the curve) under the fed state were about 30% lower than under the fasting state at day 1 but were similar at steady state. In analogy to skin, plasma exposure showed no between‐group difference at steady state. Accumulation ratios were higher in the skin than in plasma. Correcting for plasma protein binding (~90%), dermal doxycycline exposure was approximately threefold higher than unbound plasma exposure.

Conclusions

At steady state, doxycycline concentrations in the skin of fed and fasting healthy volunteers were comparable. Doxycycline's efficacy in rosacea is possibly due to considerable dermal accumulation of unbound doxycycline and is independent of the effect of food.

Regulation of T helper cell responses during antigen presentation by norepinephrine-exposed endothelial cells

Dermal blood vessels and regional lymph nodes are innervated by sympathetic nerves and, under stress, sympathetic nerves release norepinephrine (NE). Exposure of primary murine dermal microvascular endothelial cells (pDMECs) to NE followed by co-culture with Langerhans cells (LCs), responsive CD4+ T-cells and antigen resulted in modulation of CD4+ T-cell responses. NE-treatment of pDMECs induced increased production of interleukin (IL)-6 and IL-17A while down-regulating interferon (IFN)-γ and IL-22 release. This effect did not require contact between pDMECs and LCs or T-cells and depended upon pDMEC production of IL-6. The presence of NE-treated pDMECs increased the proportion of CD4+ T-cells expressing intracellular IL-17A and increased IL-17A mRNA while decreasing the proportion of IFN-γ- or IL-22-expressing CD4+ T-cells and mRNA levels for those cytokines. Retinoic acid receptor-related orphan receptor gamma (ROR-γt) mRNA was significantly increased in CD4+ T-cells while T-box transcription factor (T-bet) mRNA was decreased. Intradermal administration of NE prior to hapten immunization at the injection site produced a similar bias in draining lymph node CD4+ T-cells towards IL-17A and away from IFN-γ and IL-22 production. Under stress, release of NE may have significant regulatory effects on the outcome of antigen presentation through actions on ECs with enhancement of inflammatory skin disorders involving IL-17/T helper type 17 (Th17) cells.

Comorbidities in rosacea: A systematic review and update

BACKGROUND

Rosacea is linked to abnormalities of cutaneous vasculature and dysregulation of the inflammatory response. Recent reports on rosacea have shown a significant association with cardiovascular, gastrointestinal, and psychiatric diseases, all of which may affect morbidity and mortality among these patients.

OBJECTIVE

To review available data regarding comorbidities associated with rosacea, discuss their pathogenesis, and highlight the evaluation of affected patients.

METHODS

We performed a complete and systematic literature review in PubMed/Medline, Embase, and the Cochrane Collaboration databases, searching for all articles on possible associated diseases that have been reported with rosacea, with no limits on publication date, participant age, sex, or nationality.

RESULTS

A total of 29 studies were included in this systematic review, including 14 case-control, 8 cross-sectional, and 7 cohort studies. Statistically significant association with rosacea has been mostly demonstrated with depression (n = 117,848 patients), hypertension (n = 18,176), cardiovascular diseases (n = 9739), anxiety disorder (n = 9079), dyslipidemia (n = 7004), diabetes mellitus (n = 6306), migraine (n = 6136), rheumatoid arthritis (n = 4192), Helicobacter pylori infection (n = 1722), ulcerative colitis (n = 1424), and dementia (n = 1194).

LIMITATIONS

Limitations included the accuracy of the published data, potential patient selection, and possible confounding factors. The true nature of the drawn correlations is uncertain, and causality cannot be established.

CONCLUSIONS

Rosacea is associated with a number of systemic disorders. Recognition of these conditions is critical to providing appropriate screening and management of affected patients.

The cre-inducer doxycycline lowers cytokine and chemokine transcript levels in the gut of mice

The antibiotic doxycycline is used as an inducer of recombinase (cre)-based conditional gene knockout in mice, which is a common tool to show the effect of disrupted gene functions only in one period of a research animal's life. However, other types of such antibiotics have been shown to have a strong impact on the immune system. Here we show that in C57BL/6 mice, the most commonly applied strain for genetic modification, doxycycline treatment lowered transcription of the genes Il1b, Il10, Il18, Tnf, Cxcl1, and Cxcl2 in the ileum, and of the gene Il18 in colon. Cytokines and chemokines encoded by these genes are important in the disease expression in a range of mouse models. Although protein abundances only rarely correlate 100% to transcript levels, and the net result, therefore, may be less dramatic, it seems reasonable to be aware that a broad spectrum antibiotic, such as doxycycline, may impact the transgenic animal in ways unrelated to the activation of the gene deletion.

Calreticulin attenuated microwave radiation-induced human microvascular endothelial cell injury through promoting actin acetylation and polymerization

Recent work reveals that actin acetylation modification has been linked to different normal and disease processes and the effects associated with metabolic and environmental stressors. Herein, we highlight the effects of calreticulin on actin acetylation and cell injury induced by microwave radiation in human microvascular endothelial cell (HMEC). HMEC injury was induced by high-power microwave of different power density (10, 30, 60, 100 mW/cm2, for 6 min) with or without exogenous recombinant calreticulin. The cell injury was assessed by lactate dehydrogenase (LDH) activity and Cell Counting Kit-8 in culture medium, migration ability, intercellular junction, and cytoskeleton staining in HMEC. Western blotting analysis was used to detected calreticulin expression in cytosol and nucleus and acetylation of globular actin (G-actin). We found that HMEC injury was induced by microwave radiation in a dose-dependent manner. Pretreatment HMEC with calreticulin suppressed microwave radiation-induced LDH leakage and increased cell viability and improved microwave radiation-induced decrease in migration, intercellular junction, and cytoskeleton. Meanwhile, pretreatment HMEC with exogenous calreticulin upregulated the histone acetyltransferase activity and the acetylation level of G-actin and increased the fibrous actin (F-actin)/G-actin ratio. We conclude that exogenous calreticulin protects HMEC against microwave radiation-induced injury through promoting actin acetylation and polymerization.

Purinergic signaling and blood vessels in health and disease

Purinergic signaling plays important roles in control of vascular tone and remodeling. There is dual control of vascular tone by ATP released as a cotransmitter with noradrenaline from perivascular sympathetic nerves to cause vasoconstriction via P2X1 receptors, whereas ATP released from endothelial cells in response to changes in blood flow (producing shear stress) or hypoxia acts on P2X and P2Y receptors on endothelial cells to produce nitric oxide and endothelium-derived hyperpolarizing factor, which dilates vessels. ATP is also released from sensory-motor nerves during antidromic reflex activity to produce relaxation of some blood vessels. In this review, we stress the differences in neural and endothelial factors in purinergic control of different blood vessels. The long-term (trophic) actions of purine and pyrimidine nucleosides and nucleotides in promoting migration and proliferation of both vascular smooth muscle and endothelial cells via P1 and P2Y receptors during angiogenesis and vessel remodeling during restenosis after angioplasty are described. The pathophysiology of blood vessels and therapeutic potential of purinergic agents in diseases, including hypertension, atherosclerosis, ischemia, thrombosis and stroke, diabetes, and migraine, is discussed.

Nerve-derived transmitters including peptides influence cutaneous immunology

Clinical observations suggest that the nervous and immune systems are closely related. For example, inflammatory skin disorders; such as psoriasis, atopic dermatitis, rosacea and acne; are widely believed to be exacerbated by stress. A growing body of research now suggests that neuropeptides and neurotransmitters serve as a link between these two systems. Neuropeptides and neurotransmitters are released by nerves innervating the skin to influence important actors of the immune system, such as Langerhans cells and mast cells, which are located within close anatomic proximity. Catecholamines and other sympathetic transmitters that are released in response to activation of the sympathetic nervous system are also able to reach the skin and affect immune cells. Neuropeptides appear to direct the outcome of Langerhans cell antigen presentation with regard to the subtypes of Th cells generated and neuropeptides induce the degranulation of mast cells, among other effects. Additionally, endothelial cells, which release many inflammatory mediators and express cell surface molecules that allow leukocytes to exit the bloodstream, appear to be regulated by certain neuropeptides and transmitters. This review focuses on the evidence that products of nerves have important regulatory activities on antigen presentation, mast cell function and endothelial cell biology. These activities are highly likely to have clinical and therapeutic relevance.

Norepinephrine and adenosine-5'-triphosphate synergize in inducing IL-6 production by human dermal microvascular endothelial cells

Endothelial cells (ECs) play important roles in cutaneous inflammation, in part, by release of inflammatory chemokines/cytokines. Because dermal blood vessels are innervated by sympathetic nerves, the sympathetic neurotransmitter norepinephrine (NE) and the co-transmitter adenosine-5'-triphosphate (ATP) may regulate expression of EC inflammatory factors. We focused on IL-6 regulation because it has many inflammatory and immune functions, including participation in Th17 cell differentiation. Strikingly, NE and ATP synergistically induced release of IL-6 by a human dermal microvascular endothelial cell line (HMEC-1). Adrenergic antagonist and agonist studies indicated that the effect of NE on induced IL-6 release is primarily mediated by β2-adrenergic receptors (ARs). By real-time PCR IL-6 mRNA was also synergistically induced in HMEC-1 cells. This synergistic effect of NE and ATP was reproduced in primary human dermal endothelial cells (pHDMECs) and is also primarily mediated by β2-ARs. Under conditions of stress, activation of the symphathetic nervous system may lead to release of ATP and NE by sympathetic nerves surrounding dermal blood vessels with induction of IL-6 production by ECs. IL-6 may then participate in immune and inflammatory processes including generation of Th17 cells. Production of IL-6 in this manner might explain stress-induced exacerbation of psoriasis, and perhaps, other skin disorders involving Th17-type immunity.

N-acetyl-S-farnesyl-l-cysteine suppresses chemokine production by human dermal microvascular endothelial cells

Isoprenylcysteine (IPC) molecules modulate G-protein-coupled receptor signalling. The archetype of this class is N-acetyl-S-farnesyl-l-cysteine (AFC). Topical application of AFC locally inhibits skin inflammation and elicitation of contact hypersensitivity in vivo. However, the mechanism of these anti-inflammatory effects is not well understood. Dermal microvascular endothelial cells (ECs) are involved in inflammation, in part, by secreting cytokines that recruit inflammatory cells. We have previously shown that the sympathetic nerve cotransmitter adenosine-5'-triphosphate (ATP) and adenosine-5'-O-(3-thio) triphosphate (ATPγS), an ATP analogue that is resistant to hydrolysis, increase secretion of the chemokines CXCL8 (interleukin-8), CCL2 (monocyte chemotactic protein-1) and CXCL1 (growth-regulated oncogene α) by dermal microvascular ECs. Production of these chemokines can also be induced by the exposure to the proinflammatory cytokine TNFα. We have now demonstrated that AFC dose-dependently inhibits ATP-, ATPγS- and TNFα-induced production of CXCL1, CXCL8 and CCL2 by a human dermal microvascular EC line (HMEC-1) in vitro under conditions that do not affect cell viability. Inhibition of ATPγS- or TNFα-stimulated release of these chemokines was associated with reduced mRNA levels. N-acetyl-S-geranyl-l-cysteine, an IPC analogue that is inactive in inhibiting G-protein-coupled signalling, had greatly reduced ability to suppress stimulated chemokine production. AFC may exert its anti-inflammatory effects through the inhibition of chemokine production by stimulated ECs.

Rosacea: The cytokine and chemokine network

Rosacea is one of the most common dermatoses of adults. Recent studies have improved our understanding of the pathophysiology of rosacea. Current concepts suggest that known clinical trigger factors of rosacea such as UV radiation, heat, cold, stress, spicy food, and microbes modulate Toll-like receptor signaling, induce reactive oxygen species, as well as enhance antimicrobial peptide and neuropeptide production. Downstream of these events cytokines and chemokines orchestrate an inflammatory response that leads to the recruitment and activation of distinct leukocyte subsets and induces the characteristic histopathological features of rosacea. Here we summarize the current knowledge of the cytokine and chemokine network in rosacea and propose pathways that may be of therapeutic interest.

Clinical, cellular, and molecular aspects in the pathophysiology of rosacea

Rosacea is a chronic inflammatory skin disease of unknown etiology. Although described centuries ago, the pathophysiology of this disease is still poorly understood. Epidemiological studies indicate a genetic component, but a rosacea gene has not been identified yet. Four subtypes and several variants of rosacea have been described. It is still unclear whether these subtypes represent a "developmental march" of different stages or are merely part of a syndrome that develops independently but overlaps clinically. Clinical and histopathological characteristics of rosacea make it a fascinating "human disease model" for learning about the connection between the cutaneous vascular, nervous, and immune systems. Innate immune mechanisms and dysregulation of the neurovascular system are involved in rosacea initiation and perpetuation, although the complex network of primary induction and secondary reaction of neuroimmune communication is still unclear. Later, rosacea may result in fibrotic facial changes, suggesting a strong connection between chronic inflammatory processes and skin fibrosis development. This review highlights recent molecular (gene array) and cellular findings and aims to integrate the different body defense mechanisms into a modern concept of rosacea pathophysiology.

Characterization of a novel angiogenic model based on stable, fluorescently labelled endothelial cell lines amenable to scale-up for high content screening

BACKGROUND

Blood vessel formation is important for many physiological and pathological processes and is therefore a critical target for drug development. Inhibiting angiogenesis to starve a tumour or promoting 'normalization' of tumour vasculature in order to facilitate delivery of anticancer drugs are both areas of active research. Recapitulation of vessel formation by human cells in vitro allows the investigation of cell-cell and cell-matrix interactions in a controlled environment and is therefore a crucial step in developing HCS (high content screening) and HTS (high throughput screening) assays to search for modulators of blood vessel formation. HUVECs (human umbilical-vein endothelial cells) exemplify primary cells used in angiogenesis assays. However, primary cells have significant limitations that include phenotypic decay and/or senescence by six to eight passages in culture, making stable integration of fluorescent markers and large-scale expansion for HTS problematic. To overcome these limitations for HTS, we developed a novel angiogenic model system that employs stable fluorescent endothelial cell lines based on immortalized HMECs (human microvascular endothelial cell). We then evaluated HMEC cultures, both alone and co-cultured with an EMC (epicardial mesothelial cell) line that contributes vascular smooth muscle cells, to determine the suitability for HTS or HCS.

RESULTS

The endothelial and epicardial lines were engineered to express a panel of nuclear- and cytoplasm-localized fluorescent proteins to be mixed and matched to suit particular experimental goals. HMECs retained their angiogenic potential and stably expressed fluorescent proteins for at least 13 passages after transduction. Within 8 h after plating on Matrigel, the cells migrated and coalesced into networks of vessel-like structures. If co-cultured with EMCs, the branches formed cylindrical-shaped structures of HMECs surrounded by EMC derivatives reminiscent of vessels. Network formation measurements revealed responsiveness to media composition and control compounds.

CONCLUSIONS

HMEC-based lines retain most of the angiogenic features of primary endothelial cells and yet possess long-term stability and ease of culture, making them intriguing candidates for large-scale primary HCS and HTS (of ~10000-1000000 molecules). Furthermore, inclusion of EMCs demonstrates the feasibility of using epicardial-derived cells, which normally contribute to smooth muscle, to model large vessel formation. In summary, the immortalized fluorescent HMEC and EMC lines and straightforward culture conditions will enable assay development for HCS of angiogenesis.

Calcitonin gene-related peptide inhibits chemokine production by human dermal microvascular endothelial cells

This study examined whether the sensory neuropeptide calcitonin gene-related peptide (CGRP) inhibits release of chemokines by dermal microvascular endothelial cells. Dermal blood vessels are associated with nerves containing CGRP, suggesting that CGRP-containing nerves may regulate cutaneous inflammation through effects on vessels. We examined CGRP effects on stimulated chemokine production by a human dermal microvascular endothelial cell line (HMEC-1) and primary human dermal microvascular endothelial cells (pHDMECs). HMEC-1 cells and pHDMECs expressed mRNA for components of the CGRP and adrenomedullin receptors and CGRP inhibited LPS-induced production of the chemokines CXCL8, CCL2, and CXCL1 by both HMEC-1 cells and pHDMECs. The receptor activity-modifying protein (RAMP)1/calcitonin receptor-like receptor (CL)-specific antagonists CGRP₈-₃₇ and BIBN4096BS, blocked this effect of CGRP in a dose-dependent manner. CGRP prevented LPS-induced IκBα degradation and NF-κB binding to the promoters of CXCL1, CXCL8 and CCL2 in HMEC-1 cells and Bay 11-7085, an inhibitor of NF-κB activation, suppressed LPS-induced production of CXCL1, CXCL8 and CCL2. Thus, the NF-κB pathway appears to be involved in CGRP-mediated suppression of chemokine production. Accordingly, CGRP treatment of LPS-stimulated HMEC-1 cells inhibited their ability to chemoattract human neutrophils and mononuclear cells. Elucidation of this pathway may suggest new avenues for therapeutic manipulation of cutaneous inflammation.

Dexamethasone enhances ATP-induced inflammatory responses in endothelial cells

The purinergic nucleotide ATP is released from stressed cells and is implicated in vascular inflammation. Glucocorticoids are essential to stress responses and are used therapeutically, yet little information is available that describes the effects of glucocorticoids on ATP-induced inflammation. In a human microvascular endothelial cell line, extracellular ATP-induced interleukin (IL)-6 secretion in a dose- and time-dependent manner. When cells were pretreated with dexamethasone, a prototypic glucocorticoid, ATP-induced IL-6 production was enhanced in a time- and dose-dependent manner. Mifepristone, a glucocorticoid receptor antagonist, blocked these effects. ATP-induced IL-6 release was significantly inhibited by a phospholipase C inhibitor [1-[6-[((17β)-3-methoxyestra-1,3,5[10]-trien-17-yl)amino]hexyl]-1H-pyrrole-2,5-dione (U73122)] (63.2 ± 3%, p < 0.001) and abolished by a p38 mitogen-activated protein kinase inhibitor [4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)-1H-imidazole (SB 203580)] (88 ± 1%, p < 0.001). Cells treated with dexamethasone induced mRNA expression of the purinergic P2Y(2) receptor (P2Y(2)R) 1.8- ± 0.1-fold and, when stimulated with ATP, enhanced Ca(2+) release and augmented IL-6 mRNA expression. Silencing of the P2Y(2)R by its small interfering RNA decreased ATP-induced IL-6 production by 81 ± 1% (p < 0.001). Dexamethasone enhanced the transcription rate of P2Y(2)R mRNA and induced a dose-related increase in the activity of the P2Y(2)R promoter. Furthermore, dexamethasone-enhanced ATP induction of adhesion molecule transcription and augmented the release of IL-8. Dexamethasone leads to an unanticipated enhancement of endothelial inflammatory mediator production by extracellular ATP via a P2Y(2)R-dependent mechanism. These data define a novel positive feedback loop of glucocorticoids and ATP-induced endothelial inflammation.

[Rosacea 2009 : new advances in pathophysiology, clinical staging and therapeutic strategies]

Rosacea is one of the most common dermatoses of adults. In recent years many studies have contributed to a better understanding of the pathophysiology of rosacea. They suggest that an altered innate immune response is involved in the vascular and inflammatory manifestations seen in rosacea. A good understanding of the disease and its special features is necessary for the differential diagnosis of the many clinical subtypes and for a stage- and phase-specific treatment approach. Topical treatments that are widely accepted are metronidazole and azelaic acid; agents under investigation that show promise include permethrin, calcineurin inhibitors and sulfur compounds. For systemic therapy antibiotics (tetracyclines, macrolides) and recently doxycycline in anti-inflammatory rather than anti-microbial dosages are used, as well as isotretinoin in severe cases. Findings such as rhinophyma and telangiectases can be treated using different laser systems or dermabrasion. This article gives an overview regarding rosacea, a challenging condition with multiple therapeutic options.