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Brimonidine reduces inflammation and erythema in rosacea by affecting the processes of neurogenic activation and neutrophil recruitment, according to a study published in Experimental Dermatology.
The researchers of this study analyzed the effect of brimonidine in vitro, in vivo, and in a randomized exploratory trial.
In vitro, human neutrophils were isolated from whole blood samples, treated with a brimonidine solution, and put through a transendothelial migration assay. After a neutrophil chemoattractant was added to the assay, neutrophil migration was entirely halted by the use of the brimonidine solution.
In vivo, vessel dilation of irritated mice ears was measured under a microscope after they were pretreated with either a brimonidine 0.2% solution or a vehicle solution. To assess the anti-inflammatory effects of brimonidine, leukocyte recruitment was monitored by classifying leukocytes as adherent or rolling.
Vasodilation occurred in all the irritated ears, but at 15 minutes, the ears pretreated with brimonidine had 76.5% less dilation (P <.05); at 25 minutes, they had 61% less dilation; and overall, there was 78% less dilation of arteries (P <.01). Rolling leukocytes increased by 82%, and adherent leukocytes increased by 175% after irritation in untreated ears, whereas the ears that were pretreated with brimonidine avoided leukocyte recruitment.
The exploratory trial included evaluations of biopsies for neutrophils and cytokines on day 5 after 4 days of using randomly assigned anti-inflammatory agents (brimonidine tartrate 0.33% gel, clobetasol propionate 0.05% cream, desonide 0.05% cream, and diclofenac sodium 3% gel) before a UV light exposure.
All 37 participants were white men, and 86.5% had skin phototype III. There was a reduction in neutrophil recruitment by 71.9% for clobetasol treatment (P =.003), 62.2% for diclofenac treatment (P =.001), and 53.9% for brimonidine treatment (P =.026) among UV responders (n = 22).
Future studies need to evaluate the long-term effect of brimonidine gel on rosacea symptoms, especially erythema.
The researchers concluded that these findings suggest that brimonidine prevents leukocyte recruitment by affecting neutrophils in the endothelium, which leads to the anti-inflammatory properties of brimonidine gel. This therapy “may be more than a symptomatic treatment, having a preventive effect on erythema in rosacea in response to psychological stress, external factors, or in an inflammatory environment.”
Disclosure
This study was supported by Nestlé Skin Health. Please refer to reference for a complete list of authors’ disclosures.
Reference
Bertino B, Blanchet-Réthoré S, Thibaut de Ménonville S, et al. Brimonidine displays anti-inflammatory properties in the skin through the modulation of the vascular barrier function [published online Oct. 5, 2018]. Exp Dermatol. doi: 10.1111/exd.13793
