Ontogenesis of the Mouse Ocular Surface Lymphatic Vascular Network.

Purpose: Ocular lymphatic vessels play major physiological role in eye homeostasis and their dysfunction can contribute to the progression of several eye diseases. In this study, we characterized their spatiotemporal development and the cellular mechanisms occurring during their ontogenesis in the mouse eye.

Methods: Whole mount immunofluorescent staining and imaging by standard or lightsheet fluorescence microscopy were performed on late embryonic and early postnatal eye mouse samples.

Lymphatics in Eye Fluid Homeostasis: Minor Contributors or Significant Actors?

Lymphatic vessels exert major effects on the maintenance of interstitial fluid homeostasis, immune cell trafficking, lipid absorption, tumor progression and metastasis. Recently, novel functional roles for the lymphatic vasculature have emerged, which can be associated with pathological situations. Among them, lymphatics have been proposed to participate in eye aqueous humor drainage, with potential consequences on intraocular pressure, a main risk factor for progression of glaucoma disease.

Eye lymphatic defects induced by bone morphogenetic protein 9 deficiency have no functional consequences on intraocular pressure.

Aqueous humor drainage is essential for the regulation of intraocular pressure (IOP), a major risk factor for glaucoma. The Schlemm's canal and the non-conventional uveoscleral pathway are known to drain aqueous humor from the eye anterior chamber. It has recently been reported that lymphatic vessels are involved in this process, and that the Schlemm's canal responds to some lymphatic regulators.

Bone Morphogenetic Protein 9 Regulates Early Lymphatic-Specified Endothelial Cell Expansion during Mouse Embryonic Stem Cell Differentiation.

Exogenous cues involved in the regulation of the initial steps of lymphatic endothelial development remain largely unknown. We have used an in vitro model based on the co-culture of vascular precursors derived from mouse embryonic stem cell (ESC) differentiation and OP9 stromal cells to examine the first steps of lymphatic specification and expansion. We found that bone morphogenetic protein 9 (BMP9) induced a dose-dependent biphasic effect on ESC-derived vascular precursors.

Lymphatic collecting vessel maturation and valve morphogenesis.

The lymphatic vasculature plays an essential role in the maintenance of tissue interstitial fluid balance and in the immune response. After capture of fluids, proteins and antigens by lymphatic capillaries, lymphatic collecting vessels ensure lymph transport. An important component to avoid lymph backflow and to allow a unidirectional flow is the presence of intraluminal valves.