Inhibition of mast cell infiltration in an LL-37-induced rosacea mouse model using topical brimonidine tartrate 0.33% gel.

Brimonidine is a highly selective α2-adrenergic receptor agonist approved by the FDA for the treatment of rosacea. Rosacea is a major clinical disease with vasodilatation and rash on the centre of the face, and that brimonidine as a vasoconstrictor can act as a remedy for rosacea. However, there is no study of how brimonidine has an effect on rosacea-related immune cells or mechanisms in the skin to improve rosacea. In this study, we observed that clinical features of rosacea induced by LL-37 in Balb/c mice were improved after the application of brimonidine gel, and we also showed a marked decrease in the number of inflammatory cells, especially mast cells (MCs) histologically. Furthermore, we confirmed that mRNA levels of MC enzymes increased by LL-37 were reduced by brimonidine gel. To our knowledge, we first found that brimonidine has a mechanism of treating rosacea by reducing the number and mRNA levels of MC-specific enzymes, an important immune cell in the pathogenesis of rosacea.

Activation of p38 and Erk Mitogen-Activated Protein Kinases Signaling in Ocular Rosacea.

Purpose: Rosacea-related cutaneous inflammation is a common cause of ocular surface disease. Currently, there are no specific pharmacologic therapies to treat ocular rosacea. Here, we aimed at determining the differences in intracellular signaling activity in eyelid skin from patients with and without ocular rosacea. Methods: This was an observational, comparative case series including 21 patients undergoing lower lid ectropion surgery at one practice during 2013 and 2014 (18 patients with rosacea, 13 control patients), and 24 paraffin-embedded archival samples from Albany Medical Center, selected randomly (12 patients with rosacea, 12 control patients). Cutaneous biopsies resulting from elective lower lid ectropion surgery were analyzed by Proteome Profiler Human Phospho-Kinase Array, Western blot, and/or immunohistochemistry. Results: Samples derived from ocular rosacea patients showed increased levels of phosphorylated (active) p38 and Erk kinases. Phosphoproteins were mainly localized to the epidermis of affected eyelids. Conclusions: This finding provides a novel potential therapeutic target for treatment of ocular rosacea and possibly other forms of rosacea. Further testing is required to determine if p38 and Erk activation have a causal role in ocular rosacea. The selective activation of keratinocytes in the affected skin suggests that topical pathway inhibition may be an effective treatment that will ultimately prevent ocular surface damage due to ocular rosacea.

Association of Rosacea With Risk for Glioma in a Danish Nationwide Cohort Study.

IMPORTANCE: Rosacea, a common facial skin disorder, has a poorly understood pathogenesis in which increased matrix metalloproteinase activity might play an important role. Glioma accounts for 80% of all primary malignant tumors in the central nervous system, and these tumors also show upregulation of certain matrix metalloproteinases. OBJECTIVE: To investigate the association between rosacea and the risk for glioma. DESIGN, SETTING, AND PARTICIPANTS: Nationwide cohort study of the Danish population from individual-level linkage of administrative registers. All Danish citizens 18 years or older from January 1, 1997, to December 31, 2011, were eligible for inclusion. A total of 5 484 910 individuals were eligible for analysis; of these, 68 372 had rosacea and 5 416 538 constituted the reference population. Data were analyzed from July 14 to August 10, 2015. MAIN OUTCOMES AND MEASURES: The outcome of interest was a diagnosis of glioma. Incidence rates per 10 000 person-years were calculated, and incidence rate ratios adjusted for age, sex, and socioeconomic status were estimated by Poisson regression distribution models. RESULTS: Of the 5 484 910 individuals in the study population, 21 118 individuals developed glioma during the study period, including 20 934 of the 5 416 538 individuals in the reference population (50.4% women; mean [SD] age, 40.8 [19.7] years) and 184 of the 68 372 patients with rosacea (67.3% women; mean [SD] age, 42.2 [16.5] years). The incidence rate (95% CI) of glioma was 3.34 (3.30-3.39) in the reference population and 4.99 (4.32-5.76) in patients with rosacea. The adjusted incidence rate ratio (95% CI) of glioma in patients with rosacea was 1.36 (1.18-1.58) in our primary analysis. When analyses were limited to patients with a primary diagnosis of rosacea by a hospital dermatologist (n = 5964), the adjusted incidence rate ratio was 1.82 (1.16-2.86). CONCLUSIONS AND RELEVANCE: Rosacea was associated with a significantly increased risk for glioma in a nationwide cohort. This association may be mediated, in part, by mechanisms dependent on matrix metalloproteinases. Increased focus on neurologic symptoms in patients with rosacea may be warranted.

Decreased serum paraoxonase and arylesterase activities in patients with rosacea.

BACKGROUND: Recent evidence suggests that oxidative stress may be an important phenomenon in the pathophysiology of rosacea. Paraoxonase-1 (PON1) is an antioxidant enzyme with three activities: paraoxonase, arylesterase and dyazoxonase. In this study, we evaluated serum paraoxonase and arylesterase activities, and serum lipid hydroperoxide (LOOH) levels in patients with rosacea in comparison to healthy controls. MATERIAL AND METHOD: The study included 39 rosacea patients and healthy controls, consisting of 40 age- and sex-matched healthy volunteers. Serum paraoxonase and arylesterase activities were measured using paraoxon and phenylacetate substrates. Serum LOOH levels were measured with the ferrous ion oxidation-xylenol orange assay. RESULTS: In rosacea group mean serum paraoxonase and arylesterase activities were 74.54 ± 38.30 U L(-1) and 141.29 ± 22.27 kU L(-1) respectively, which were significantly lower than controls (P = 0.010, 0.005; respectively). Mean serum LOOH level of rosacea group was 8.17 ± 1.91 µmol L(-1) which was significantly higher than controls (P = 0.009). There were no statistically significant differences between the clinical subtypes of the disease, menopause situation or ocular involvement with the respect to the serum paraoxonase and arylesterase activities and LOOH levels (all; P > 0.05). CONCLUSIONS: Serum PON1 enzyme activities have decreased significantly in rosacea. These findings support that decreased PON1 activity and increased oxidative stress may play a role in the pathogenesis of rosacea. Further studies are needed to elucidate the role of PON1 activity in the pathophysiology of rosacea.

Regulation of kallikrein-related peptidases in the skin - from physiology to diseases to therapeutic options.

Kallikrein-related peptidases (KLKs) constitute a family of 15 highly conserved serine proteases, which show a tissue-specific expression profile. This made them valuable tumour expression markers. It became evident that KLKs are involved in many physiological processes like semen liquefaction and skin desquamation. More recently, we have learnt that they are involved in many pathophysiological conditions and diseases making them promising target of therapeutic intervention. Therefore, regulation of KLKs raised the interest of numerous reports. Herein, we summarise the current knowledge on KLKs regulation with an emphasis on skin-relevant KLKs regulation processes. Regulation of KLKs takes place on the level of transcription, on protease activation and on protease inactivation. A variety of protease inhibitors has been described to interact with KLKs including the irreversible serine protease inhibitors (SERPINs) and the reversible serine protease inhibitors of Kazal-type (SPINKs). In an attempt to integrate current knowledge, we propose that KLK regulation has credentials as targets for therapeutic intervention.

Epidermal proteases in the pathogenesis of rosacea.

A number of different proteases and their inhibitors have a role in skin physiology and in the pathophysiology of inflammatory skin diseases. Proteases are important in the desquamation process and orderly regulation of the skin's barrier function. On the basis of the catalytic domain, proteases are classified into aspartate-, cysteine-, glutamate-, metallo-, serine-, and threonine proteases. Particularly, serine proteases (SPs) contribute to epidermal permeability barrier homeostasis, as acute barrier disruption increases SP activity in skin and inhibition by topical SP inhibitors accelerated recovery of barrier function after acute abrogation. In rosacea, increased levels of the vasoactive and inflammatory host-defense peptide cathelicidin LL-37 and its proteolytic peptide fragments were found, which were explained by an abnormal production of tryptic activity originating from kallikrein-related peptidase (KLK) 5. It is therefore possible that also other proteases, even from microbial or parasite origin, have a role in rosacea by forming alternate angiogenic and proinflammatory cathelicidin peptides. Further, the regulation of protease activity, in particular KLK-5 activity, might have a role in rosacea. This review briefly summarizes our current knowledge about keratinocyte-derived proteases and protease inhibitors, which might have a role in the pathophysiology of rosacea.

Intestinal alkaline phosphatase: the molecular link between rosacea and gastrointestinal disease?

Rosacea is a common inflammatory condition of the facial skin of unknown etiology, which frequently occurs in combination with gastrointestinal disorders. Many dietary and hormonal factors are known to affect the severity of rosacea symptoms, several of which also modulate the activity of the enzyme intestinal alkaline phosphatase (IAP). The role of IAP in inhibiting an inflammatory response to intestinal bacteria suggests a mechanism by which intestinal pathologies may be linked to the skin inflammation characteristic of rosacea. Analysis of alkaline phosphatase activity is routinely performed on blood samples, and methods to quantify enzyme activity of the intestinal isoform specifically have been described. Correlations between IAP activity and rosacea symptoms in patients and controls can thus be screened by noninvasive and inexpensive means. If IAP activity is found to be low in rosacea patients, acute symptoms could be treated with oral IAP supplementation, and trials of IAP-activating medications currently used in gastrointestinal disease could be initiated in rosacea patients. More importantly, the safe and long-term control of rosacea could be undertaken by patients themselves through dietary modification to naturally increase IAP activity.

Tear fluid levels of MMP-8 are elevated in ocular rosacea--treatment effect of oral doxycycline.

BACKGROUND: Ocular rosacea (OcR) is a chronic inflammatory disease especially affecting lid margins. Previous studies have shown that it is accompanied by increased levels and activation of tear fluid gelatinases. Matrix metalloproteinase 8 (MMP-8; collagenase 2) levels and activation are commonly elevated in many inflammatory conditions. Therefore we studied here whether MMP-8 concentration and activation in tear fluid are increased also in OcR, and if an oral doxycycline regimen could rectify the situation. METHODS: Tear fluid samples were collected from 22 OcR patients and 22 healthy controls. The OcR patients were then treated with an oral doxycycline regimen for 8 weeks and tear fluid samples collected again after 4 and 8 weeks. Conjunctival brush cytology and patients' subjective symptoms were scored. MMP-8 concentrations in the tear fluid were assessed by immunofluorometric assay and the molecular forms and isoenzyme expression of MMP-8 were studied by Western immunoblotting. RESULTS: The mean MMP-8 concentration was statistically significantly higher in OcR (156.8+/-207.4 mug/ml) than in the normal subjects (53.5+/-66.7 mug/ml) (P=0.036), but decreased to 79.2+/-141.6 mug/l and 53.6+/-75.2 mug/l after 4 and 8 weeks doxycycline treatment, respectively. There was a statistically significant difference between the untreated OcR and the MMP-8 results after 4 or 8 weeks of oral doxycycline (P=0.041 and 0.069, respectively) and the OcR patients experienced statistically significant relief of their subjective symptoms (P=0.0001) after the doxycycline regimen. Both the normal and OcR tear fluid contained the larger, 60-80 kDa highly- glycosylated polymorphonuclear leukocyte-type MMP-8 isoform in Western immunoblotting, but not the 45-55 kDa less glycosylated mesenchymal-type isoform. MMP-8 activation was in practice present only in the OcR samples, and was inhibited by oral doxycycline. CONCLUSIONS: MMP-8 concentration and activation degree in tear fluid are increased in OcR, probably reflecting increased inflammatory activity. Doxycycline effectively reduces these pathologically excessive levels and activation of MMP-8, and relieves patients' subjective symptoms.

Group IIA phospholipase A(2) concentration of tears in patients with ocular rosacea.

PURPOSE: To determine the concentration of group IIA phospholipase A(2) (GIIAPLA(2)) in tears of patients with ocular rosacea, and to compare it with GIIAPLA(2) concentration in tears of age-matched healthy controls. METHODS: The GIIAPLA(2) concentration in tears was measured with a time-resolved fluoroimmunoassay in 21 patients with ocular rosacea (mean age 55.6+/-9.2 years) and in 21 normal subjects (mean age 53.4+/-8.2 years). Conjunctival brush cytology was carried out and eosinophils, neutrophils, lymphocytes, squamous epithelial cells, columnar epithelial cells, metaplastic changes and goblet cells were calculated separately. RESULTS: The GIIAPLA (2) concentration in tears was statistically significantly lower in patients with ocular rosacea (31.0+/-18.4 microg/ml, p=0.0099) and, more specifically, in patients who had dry eye (25.8+/-15.1 microg/ml, p=0.0034), compared to that in normal controls. There was no correlation between the GIIAPLA (2) content of tears and the conjunctival cells collected by the brush cytology. CONCLUSION: The tears of patients with dry eye symptoms due to ocular rosacea have decreased GIIAPLA (2) content. The pathogenic importance of this finding is discussed.

Regulation of MMP-9 activity in human tear fluid and corneal epithelial culture supernatant.

PURPOSE: To evaluate human corneal epithelial culture supernatant and tear fluid for the presence of activators and inhibitors of matrix metalloproteinase (MMP)-9, MMP-3, and tissue inhibitor of metalloproteinase (TIMP)-1, respectively, and to evaluate the effect of MMP-3 on the activation of MMP-9 in these specimens. METHODS: Unstimulated tear fluid was collected from patients with ocular rosacea and normal control subjects. Levels of MMP-9, MMP-3, and TIMP-1 were determined by enzyme-linked immunosorbent assay (ELISA) and/or immunoblot analysis. Supernatants from primary human corneal epithelial cultures and human tear fluid were incubated with MMP-3. Cultured epithelial cells and their supernatants were also treated with doxycycline before MMP-3 was added. Gelatin zymography was used to identify activated 82-kDa MMP-9. MMP-9 activity was assessed with a commercial MMP-9 activity assay system. RESULTS: MMP-9 and TIMP-1 were detected at significantly higher concentrations in rosacea-affected than in normal tear fluids. MMP-3 was detected exclusively in the tear fluid of patients with ocular rosacea who had corneal epithelial disease. Treatment of the supernatant and tear fluid with MMP-3 resulted in two bands with molecular weights of 92 kDa and 82 kDa, representing pro-MMP-9 and activated MMP-9, respectively. Doxycycline added to the conditioned media did not affect activation of MMP-9 by MMP-3. However, 24-hour treatment of corneal epithelial cultures with doxycycline resulted in a lower concentration and activity of MMP-9 in their supernatants. CONCLUSIONS: MMP-9 and TIMP-1 are produced by the human corneal epithelium and are present in tear fluid. MMP-3 alone is sufficient to activate MMP-9 on the ocular surface. Doxycycline does not directly inhibit this activation by MMP-3, but it decreases MMP-9 activity when added to corneal epithelial cultures.

[Angiotensin-converting enzyme (ACE). Increased serum activities in patients with dermatological diseases (author's transl)]. / Angiotensin-Converting Enzyme (ACE). Erhöhte Enzymaktivitäten im Serum bei dermatologischen krankheiten.

Serum activities of ACE were investigated in 40 patients with dermatological disease and in nine patients with sarcoidosis. The method of Cushman and Cheung, modified according to Lieberman, was used. Both sarcoidosis patients and patients with dermatological diseases showed marked elevations of ACE-activity. The increase in ACE-activity might result from inflammation and immunological events.