Toll-like receptors and vascular markers in ocular rosacea

To delineate signals by which the vascular abnormalities inherent to ocular rosacea arise and to correlate these signals with elements of the innate immune system.

Experimental study. Immunohistochemical staining was performed for a variety of vascular markers and for toll-like receptor-4 on eyelid biopsies taken from patients with ocular rosacea and normal controls. Statistical comparisons were then performed between the 2 groups.

Immunohistochemical staining for CD31 and integrin-β-3 did not demonstrate any statistically significant differences between eyelids from patients with ocular rosacea and normal controls. Cutaneous biopsies from ocular rosacea patients demonstrated statistically significant enrichments of intercellular adhesion molecule-1 and CD105 among arterioles, whereas there were no statistically significant differences in the venules between normal controls and ocular rosacea patients. The correlation between the number of toll-like receptor-4-positive cells and each vascular marker was statistically significant.

Cutaneous biopsies of the eyelid did not demonstrate an increase in the total number of blood vessels. However, the vascular abnormalities that are typical of ocular rosacea represent activated, inflamed vessels, and these phenomena may be mediated by intercellular adhesion molecule and CD105. Furthermore, the strong correlations between toll-like receptor-4 and each vascular marker suggest that the innate immune system may govern the cutaneous effects of ocular rosacea. Intercellular adhesion molecule, CD105, and toll-like receptor-4 may represent important therapeutic targets in the management of this disease.