title: An immunohistochemical study of the extracellular matrix of the tarsal plate in the upper eyelid in human beings.
abstract: The superior tarsus is a plate of tissue that stiffens the upper eyelid, gives it support and determines its form. The purpose of the present study was to relate the composition of its extracellular matrix to its function and to report regional differences that may influence the activity of its Meibomian glands. Fourteen methanol-fixed specimens were cryosectioned for immunohistochemistry and labelled with a panel of monoclonal antibodies against a wide range of collagens, glycosaminoglycans and proteoglycans. Labelling was detected with avidin-biotin-peroxidase. A further six specimens were formalin-fixed for routine histology. The tarsal plate immunolabelled strongly for types I, III and VI collagen and for aggrecan, versican, tenascin, cartilage oligomeric matrix protein (COMP) together with a variety of glycosaminoglycans (notably chondroitin 6 sulphate). A region of strong labelling for aggrecan, dermatan sulphate and chondroitin 6 sulphate immediately surrounded the Meibomian glands. The site of labelling corresponded to a layer of acellular and amorphous matrix seen histologically that we have termed the 'territorial matrix'. The results suggested that the tarsal plate is a specialized connective tissue that is neither purely fibrous nor cartilaginous, yet has an aggrecan content that probably contributes to its stiffness. Its unique character highlights the challenge in choosing an ideal mechanical substitute. As patients with rheumatoid arthritis often have problems relating to tear film deficiency, the ability of aggrecan or COMP to act as autoantigens may be significant. An immune reaction directed against these molecules could alter tarsal gland function by interfering with the interaction between the glands and their territorial matrix.
authors.affiliation: Anatomische Anstalt, Ludwig-Maximilians-Universität, Munich, Germany. stefan.milz@aofoundation.org
authors.forename: Stefan
authors.initials: S
authors.lastname: Milz
authors.forename: Joerg
authors.initials: J
authors.lastname: Neufang
authors.forename: Ichiro
authors.initials: I
authors.lastname: Higashiyama
authors.forename: Reinhard
authors.initials: R
authors.lastname: Putz
authors.forename: Michael
authors.initials: M
authors.lastname: Benjamin
mesh_terms: D000328:Adult; D053674:Aggrecans; D064236:Cartilage Oligomeric Matrix Protein; D011508:Chondroitin Sulfate Proteoglycans / Q000032:analysis; D002809:Chondroitin Sulfates / Q000032:analysis; D024042:Collagen Type I / Q000032:analysis; D024061:Collagen Type III / Q000032:analysis; D024142:Collagen Type VI / Q000032:analysis; D003871:Dermatan Sulfate / Q000032:analysis; D005109:Extracellular Matrix / Q000737:chemistry* / Q000276:immunology / Q000648:ultrastructure*; D016326:Extracellular Matrix Proteins / Q000032:analysis*; D005143:Eyelids / Q000737:chemistry* / Q000276:immunology / Q000648:ultrastructure*; D006023:Glycoproteins / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D037181:Lectins, C-Type; D064235:Matrilin Proteins; D008537:Meibomian Glands / Q000502:physiology; D011509:Proteoglycans / Q000032:analysis; D019063:Tenascin / Q000032:analysis; D053675:Versicans
chemical_list: D053674:Aggrecans; D064236:Cartilage Oligomeric Matrix Protein; D011508:Chondroitin Sulfate Proteoglycans; D024042:Collagen Type I; D024061:Collagen Type III; D024142:Collagen Type VI; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D037181:Lectins, C-Type; D064235:Matrilin Proteins; D011509:Proteoglycans; C577553:TSP5 protein, human; D019063:Tenascin; C508322:VCAN protein, human; D053675:Versicans; D003871:Dermatan Sulfate; D002809:Chondroitin Sulfates