The purpose of this study was to research lymphatic outflow tract in the human choroid. Using a light microscopy and immunohistochemistry, structure of the choroid was investigated. We used antibodies against lymphaticendotheli-al-specificmarkers Prox-1, LYVE-1, Podoplanin, endothelial blood vessels marker CD34 and fibroblasts growth factor receptor FGFR. The choroid was found to contain lymphatic canals in choroidal stroma and a layer of choriocapillaris, and lymphatic lacunae in the suprachoroid lamina, limited endothelium-like cells, positively stained for markers of lymphatic vessels Prox-1, LYVE-1, Podoplanin, and fibroblasts and pigment cells. These endothelium-like cells were shown positive Prox-1, LYVE-1 and Podoplanin staining and negative CD34 staining; therefore we consider that these canals and lacunae are lymphatic structures.
choroid, lymphatic lacunae, lymphatic channel
1. AlmA, NilssonFE (2009). Uveoscleral outflow: A review.Exp. Eye Res., (88), 760-768.
2. DeStefanoME, MugnainiE (1997). Fine structure of the choroidal coat of the avian eye. Lymphatic vessels. Invest. Ophthalmol. Vis Sci., (38), 1241-1260.
3. GoharianI, SehiM (2014). Is there anyrolefor the choroid in glaucoma? (Sep 26).
4. HerwigMC, MünstermannK, Klarmann-SchulzU, SchlerethSL, HeindlLM, LoefflerKU, MüllerAM (2014). Expression of thelymphaticmarker podoplanin (D2-40) in human fetal eyes. Exp. Eye Res., (127), 243-251.
5. JunghansBM, CrewtherSG, CrewtherDP, PirieB (1997). Lymphatic sinusoids exist in chick but not in rabbit choroid. Aust. N. Z. J. Ophthalmol., 25(1), 103-105.
6. KrebsW, KrebsIP (1988). Ultrastructural evidence for lymphatic capillaries in the primate choroid. Arch. Ophthalmol., (106), 1615-1616.
7. KoinaME, BaxterL, AdamsonSJ, ArfusoF, HuP, MadiganMC, Chan-LingT (2015). Evidenceforlymphat-icsin thedevelopingandadulthumanchoroid. Invest. Ophthalmol. Vis. Sci., 56(2), 1310-1327.
8. NakaoS, ZandiS, KohnoR etal. (2013). Lack of lymphatics and lymph node-mediated immunity in chor-oidal neovascularization. Invest. Opthalmol. Vis. Sci., 54(6),3830. doi:10.1167/iovs.12-10341.
9. SchroedlF, BrehmerA, NeuhuberWL, KruseFE,MayCA, CursiefenC (2008). The normal humanchoroidis endowed with a significant number oflymphaticvessel endothelial hyaluronate receptor 1 (LYVE-1)-positive mac-rophages. Invest. Ophthalmol. Vis. Sci., 49(12), 5222-5229.
10. SchroedlF, Kaser-EichbergerA, SchlerethSetal. (2014). Consensus statement on the immunohis-tochemical detection of ocular lymphatic vessels. Invest. Ophthalmol. Vis. Sci., 55(10), 6440-6442. doi:10.1167/iovs.14-15638.
11. SugitaA, InokuchiT (1992). Lymphatic sinus-like structures in choroid. Jpn J. Ophthalmol., 36(4), 436-442.
12. YücelY, JohnstonM, LyT, PatelM, DrakeB,GümüşE, FraenklS, MooreS, TobbiaD, ArmstrongD, Hor-vathE, GuptaN (2009). Identification of lymphatics in the ciliary body of the human eye: A novel “uveolymphatic” outflow pathway. Exp. Eye Res., 89(5), 810-819
