Face-to-face with anti-inflammatory therapy for rosacea

Update on the pathogenesis and management of ocular rosacea: an interdisciplinary review

PURPOSE

Rosacea is one of the most common conditions affecting the ocular surface. The purpose of this review is to provide an update on the pathogenesis and treatment of rosacea based on the dermatology and ophthalmology literatures.

METHODS

Literature searches were conducted for rosacea and ocular rosacea. Preference was given to systematic reviews, meta-analysis, case-controlled studies, and documented case reports while excluding poorly documented case studies and commentaries. The data were examined and independently analyzed by more than two of the authors.

RESULTS

Rosacea is a complex inflammatory condition involving the pilosebaceous unit. Its underlying mechanism involves an interplay of the microbiome, innate immunity, adaptive immunity, environmental triggers, and neurovascular sensitivity. The latest classification of rosacea includes three dermatologic subgroups and a fourth subgroup, ocular rosacea. Ocular rosacea clinically displays many features that are analogous to the cutaneous disease, such as lid margin telangiectasia and phlyctenulosis. The role of environmental triggers in the exacerbation of ocular rosacea appears to be understudied. While lid hygiene and systemic treatment with tetracycline drugs remain the mainstay of treatment for ocular rosacea, newer dermatologic targets and therapies may have potential application for the eye disease.

CONCLUSIONS

Ocular rosacea appears to embody many of the manifestation of the dermatologic disease. Hence, the basic pathophysiologic mechanisms of the ocular and cutaneous disease are likely to be shared. Better understanding of the ocular surface microbiome and the immunologic mechanisms, may lead to novel approaches in the management of ocular rosacea.

Severe Rosacea: A Case Report

PURPOSE

To describe a case of severe rosacea with ocular involvement.

CASE REPORT

A 28-year-old female patient presented with extensive facial and ocular eruptions. She had a history of treatment with oral prednisolone due to the clinical diagnosis of lupus erythematosus (LE), which had resulted in transient improvement of the lesions, but was followed by exacerbation of the lesions. With the clinical diagnosis of severe oculofacial rosacea, she was successfully treated with oral doxycycline, steroid eye drops, and ocular lubricants. Histopathological features of skin biopsy were consistent with rosacea in the context of infection with Demodexfolliculorum. After four years, a relapse of the oculofacial lesions occurred, for which retreatment with oral tetracycline, steroid eye drops, and ocular lubricants was administered.

CONCLUSION

Rosacea can be extremely severe and disfiguring, and it can be misdiagnosed as the pathognomonic butterfly rash of LE. Demodex carriage in rosacea is consistent and may play a significant role in the severe forms.

Topical Treatment of Rosacea with Ivermectin Inhibits Gene Expression of Cathelicidin Innate Immune Mediators, LL-37 and KLK5, in Reconstructed and Ex Vivo Skin Models

Introduction

Numerous intrinsic and extrinsic factors have been associated with the pathophysiology of rosacea, including dysregulation of innate immunity. A high level of cathelicidin antimicrobial peptides (e.g., LL-37) has been shown in the facial skin of patients with rosacea. Excessive production of both LL-37 and KLK5, the serine protease responsible for its cleavage, has been suggested to play a role in the pathophysiology of rosacea. Ivermectin 10 mg/g cream, indicated for the treatment of inflammatory lesions of rosacea, is reported to have dual anti-parasitic and anti-inflammatory properties. However, the exact mechanism of action of ivermectin cream in the treatment of rosacea is unknown.

Methods

This study aimed to evaluate the effect of ivermectin on the expression of KLK5 and the subsequent effect on the maturation process of cathelicidins. Experimental studies were performed either on normal human epidermal keratinocytes (NHEK), reconstructed human epidermis (RHE) or on human skin ex vivo stimulated with calcitriol (1α,25-dihydroxyvitamin D3), which is known to induce KLK5 and LL-37 expression.

Results

The results show that ivermectin is able to inhibit KLK5 and CAMP gene expression and protein secretion in NHEK cells stimulated with calcitriol. Those results were confirmed in 3D models of the skin (RHE and skin ex vivo). The anti-inflammatory effects of ivermectin were associated with an inhibition of IL-8, IL-6 and MCP-1 (CCL2) secretion from NHEK cells.

Conclusions

These results suggest that ivermectin can prevent the inflammatory effects of rosacea triggered by abnormal LL-37 processing, through the inhibition of KLK5 gene expression in the epidermis.

Funding: Nestlé Skin Health R&D.

Electronic supplementary material

The online version of this article (doi:10.1007/s13555-017-0176-3) contains supplementary material, which is available to authorized users.

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

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

Antimicrobial peptides and wound healing: biological and therapeutic considerations

Repair of tissue wounds is a fundamental process to re-establish tissue integrity and regular function. Importantly, infection is a major factor that hinders wound healing. Multicellular organisms have evolved an arsenal of host-defense molecules, including antimicrobial peptides (AMPs), aimed at controlling microbial proliferation and at modulating the host's immune response to a variety of biological or physical insults. In this brief review, we provide the evidence for a role of AMPs as endogenous mediators of wound healing and their promising therapeutic potential for the treatment of non-life-threatening skin and other epithelial injuries.

Are Demodex mites principal, conspirator, accomplice, witness or bystander in the cause of rosacea?

As the only permanent human ectoparasite, the role of human Demodex mites in health and diseases remains largely unclarified. In view of the ecological interaction between organisms of two different species, a type of commensalism between Demodex mites and humans (the former benefit, the latter unaffected) is most likely, while parasitism occurs temporarily and spatially in the diseased state (the former benefit, the latter harmed). As part of normal skin microbiota, the causal role of Demodex mites in the initiation of rosacea can neither fulfill the classical Henle-Koch's principal nor the advanced criteria proposed by Fredericks and Relman for molecular detection of non-cultivatable microorganisms. Epidemiological analysis using Hill's criteria fails to support the causative role of Demodex mites in rosacea regarding the strength of association, specificity and temporality of association, biological gradient and plausibility as well as clinical coherence, therapeutic experimentation and medical analogy. In application of Rothman's sufficient cause model to evaluate the contribution of Demodex mites to rosacea on a population basis, Demodex mites can be regarded as a non-necessary, non-sufficient causal factor for certain forms of rosacea. Further strategies to dissect the association between Demodex mites and rosacea may include studying the possible existence of more virulent forms of mites with a higher pathogenicity, the endosymbiotic bacteria in certain life periods of mites, the interactions between mites and human hosts or between mites and environment, and to set up ex vivo culture models for Demodex mites.