Cellular basis for bimatoprost effects on human conventional outflow.

Area of Science:

• Ophthalmology
• Cell Biology
• Pharmacology

Background:

• Bimatoprost is a key ocular hypotensive agent for glaucoma treatment.
• It enhances aqueous humor outflow through both conventional and uveoscleral pathways.
• This study investigates bimatoprost's specific effects on cells within human ocular outflow tissues.

Purpose of the Study:

• To examine the effects of bimatoprost on human trabecular meshwork (TM), Schlemm's canal (SC), and ciliary smooth muscle (CSM) cells.
• To investigate the receptor activation mechanisms underlying bimatoprost's action in these ocular cells.

Main Methods:

• Primary cultures of human TM, SC, and CSM cells were utilized.
• Cellular dielectric spectroscopy (CDS) was employed to measure cell monolayer impedance and assess receptor activation.
• Prostamide receptor agonists and antagonists were used to characterize bimatoprost's signaling pathways.

Main Results:

• Bimatoprost induced a concentration-dependent increase in cell monolayer impedance in TM, SC, and CSM cells, indicating reduced cell contractility.
• Bimatoprost demonstrated equipotency with selective FP receptor agonists, suggesting specific receptor interactions.
• Signaling involved Gq pathways and was antagonized by AGN211334, with distinct agonist/antagonist behavior in TM versus SC cells.

Conclusions:

• Bimatoprost activates specific receptors in human conventional outflow pathway cells (TM and SC) to modulate intraocular pressure.
• TM cells exhibit unique autocrine receptor signaling, distinct from SC cells, which is sensitive to prostamide receptor antagonists.