Angiopoietin-1 Knockout Mice as a Genetic Model of Open-Angle Glaucoma.

PURPOSE

A leading cause of blindness worldwide, glaucoma is often caused by elevated intraocular pressure (IOP) due to impaired aqueous humor outflow from the anterior chamber through Schlemm's canal (SC) and the trabecular meshwork. Despite the large clinical burden, glaucoma research and drug development are hindered by a limited selection of preclinical models that accurately recapitulate human disease. Here, we propose thatconditional knockout mice may provide one such model. Angiopoietin/TEK (ANGPT/TEK) signaling is crucial for SC formation and integrity in mice and humans, and mice lacking TEK or its ligand ANGPT1 develop a hypomorphic SC insufficient for normal aqueous humor outflow.

METHODS

We used a comprehensive histology and physiology approach to characterize the glaucoma phenotype ofinducible knockout mice, especially focusing on retina morphology and function.

RESULTS

deletion resulted in persistent ocular hypertension beginning in the first month after birth and leading to decreased visual acuity with age due to glaucomatous neuropathy. In the neural retina, we identified marked and specific loss of the retinal ganglion cells, whereas other retinal neurons exhibited largely normal morphology and patterning. Electroretinogram recordings demonstrated reduced scotopic threshold response, further indicating loss of retinal ganglion cell function.

CONCLUSIONS

These findings highlight the potential ofconditional knockout mice as a valuable new glaucoma model.

TRANSLATIONAL RELEVANCE

Currently, few reliable, rapid-onset genetic glaucoma models are available, andknockout mice will provide an additional tool for studies of IOP-induced neural damage, mechanisms of disease progression, and novel treatment strategies.