Endothelin-1 and endothelin-converting enzyme-1 in human granulomatous pathology of eyelid: an immunohistochemical and in situ hybridization study in chalazia

• Published in: Histology and histopathology Vol. 22; no. 12; p. 1343
• Main Authors: Massai, L, Volpi, N, Carbotti, P, Fruschelli, M, Mencarelli, M, Pecorelli, A, Muscettola, M, Aglianò, M, Alessandrini, C, Grasso, G
• Format: Journal Article
• Language: English
• Published: Spain 01.12.2007
• Subjects: Adolescent; Adult; Aged; Aspartic Acid Endopeptidases - biosynthesis; Endothelin-1 - biosynthesis; Endothelin-Converting Enzymes; Eyelids - metabolism; Female; Gene Expression Regulation; Granuloma - metabolism; Humans; Immunohistochemistry - methods; In Situ Hybridization - methods; Inflammation - metabolism; Male; Metalloendopeptidases - biosynthesis; Middle Aged
• ISSN: 1699-5848
• DOI: 10.14670/HH-22.1343

Endothelin-1 (ET-1), a potent vasoconstrictor peptide, is involved in several functions of eye pathophysiology, such as regulation of intraocular tension and retinal reactive vasoconstriction. As ET-1 pro-inflammatory and fibrosing activity is emerging in different fields of pathology, we investigated the expression of ET-1 and endothelin-converting enzyme-1 (ECE-1) in chalazia, granulomatous lesions of the eyelid. ET-1 and ECE-1 were analyzed by immunohistochemistry (IHC) in twenty surgically removed chalazia, with regard to expression in eyelid structures and inflammatory infiltrate. Phenotype of ET-1 expressing inflammatory cells was established by double immunofluorescence. The cellular localization of prepro-ET-1 (pp-ET-1) mRNA and ECE-1 mRNA was studied by nonisotopic in situ hybridization (ISH). Neutrophils (PMNs), macrophages and T-lymphocytes were scattered in stroma, around alveoli and grouped in lipogranulomas. PMNs, macrophages, basal epithelium of meibomian adenomers and central ducts immunostained for ET-1. ECE-1 protein was found in meibomian adenomers, conjunctival epithelium, tarsal mucous glands and in inflammatory cells. Hybridization signals for pp-ET-1 mRNA and ECE-1 mRNA were recognized in healthy and degenerating meibomian ducts, adenomers, inflammatory cells, as well as in vessel walls. ECE-1 mRNA was also present in conjunctival epithelium and Henle's crypts. Our findings suggest that the multifunctional peptide ET-1 may have a role in molecular genesis of tissue damage in chalazia. ET-1 cytokine activity is likely to support the migration of inflammatory cells and the setting of lipogranulomas; ET-1 stimulation might contribute to proliferation of fibroblasts and collagen synthesis. ET-1 upregulation on meibomian adenomers and ducts may further enhance granulomas formation by stimulating lipid release.