Lymphatic vessels in human eyelids: an immunohistological study in dermatochalasis and chalazion

We investigated lymphatics morphology and expression of endothelin (ET-1) axis molecules in human eyelids affected by an inflammatory state (chalazion) and an age-related degenerative condition (dermatochalasis). Lymphatics were immunohistologically detected by D2-40/LYVE-1 staining. Absorbing lymphatic vessels were localized in papillary dermis and around skin appendages with distinctive morphology. In chalazion, D2-40 reactive flattened lymphatics profiles were compressed by inflammatory infiltrate; in dermatochalasis large fully opened lymphatics were observed, with a significantly wider total area (lymphatics lumen /200x field; p<0.05). The lymphatics density (number/200x field) in the two groups was within the same range. Lymphatics dilation is possibly dependent on reduction and fragmentation of dermal elastic network, as well as of oxytalanic fibers in papillary dermis of dermatochalasis, as shown by Weigert’s reaction. Multifunctional peptide ET-1, involved in vasomotion, inflammation and connective proliferation, resulted faintly and discontinuously localized on lymphatics, as well as its type A receptor. On the contrary, the consistent expression of type B receptor indicates that lymphatic endothelium is a physiological target for ET-1, whose effects are modulated by multiple pathophysiological conditions. Vasoactive factors have a role in physiology of richly vascularized eyelids, therefore morphofunctional characterization of lymphatic vessels too may be supportive in treatment options.