Abstract
Purpose :
Schlemm’s canal is a critical structure of the aqueous humor outflow pathway. It is also a therapeutic target for intraocular hypertension and glaucoma. We herein report a newly identified structure, termed lymphatic bridge, that directly connects the Schlemm’s canal to the limbal and conjunctival lymphatic pathway. Further investigation on this newly identified pathway may offer novel mechanisms and therapeutic approaches for glaucoma.
Methods :
Intact eyeballs were harvested from Prox-1-GFP (green fluorescent protein) mice (Kang, et al. Sci. Rep. 2016) and processed by a tissue clearing technique with CLARITY (Clear Lipid-exchanged Acrylamide-hybridized Rigid Imaging/Immunostaining/In situ hybridization-compatible Tissue-hYdrogel). Samples were immunolabeled with CD31 and LYVE-1 (Lymphatic vessel endothelial hyaluronan receptor-1) specific antibodies and imaged by light sheet fluorescent microscopy (LSFM). The limbal areas were examined to locate connecting channels between the Schlemm’s canal and limbal lymphatics. Additionally, in vivo anterior chamber dye injection with Texas Red dextran was performed for functional analysis.
Results :
Novel Prox-1+LYVE-1+ lymphatic bridge vessels were discovered between the Schlemm’s canal and limbal lymphatic vessels that connect with the conjunctival lymphatic pathway. The anterior chamber dye injection also confirmed the outflow of aqueous humor into the conjunctival lymphatic vessels.
Conclusions :
This study provides the first evidence of the direct connection between Schlemm’s canal and limbal and conjunctival lymphatic vessels. This pathway is distinctive from the conventional episcleral vein pathway, which warrants further investigation.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.