Region-Specific Alterations in the Trabecular Meshwork in High- and Low-Tension Glaucoma

Area of Science:

• Ophthalmology
• Glaucoma Research
• Cell Biology

Background:

• The trabecular meshwork (TM) is crucial for regulating intraocular pressure.
• Understanding TM changes in different glaucoma types is vital for targeted therapies.

Purpose of the Study:

• To compare histomorphometric and immunohistochemical alterations in the ex vivo TM of high-pressure glaucoma (HPG) and normal-tension glaucoma (NTG) patients with controls.
• To elucidate the distinct pathological mechanisms in various glaucoma subtypes.

Main Methods:

• Collected TM specimens from patients with primary open-angle glaucoma (POAG), primary angle-closure glaucoma (PACG), pseudoexfoliation glaucoma (XFG), juvenile open-angle glaucoma (JOAG), and normal-tension glaucoma (NTG).
• Analyzed TM beam width, nucleated cell count, and epithelial-mesenchymal transformation (EMT) using ImageJ.
• Performed immunohistochemistry for ANGPTL1, RSPO2, LYVE1, α-SMA, and COLL4.

Main Results:

• JOAG, POAG, and PACG showed reduced TM beam width and cell counts, with JOAG exhibiting the most significant cell loss.
• XFG and NTG had preserved JCT cell counts and high ANGPTL1 expression in the JCT.
• EMT changes and specific marker expressions (α-SMA/COLL4, LYVE1, RSPO2) varied across glaucoma types.

Conclusions:

• Distinct histopathological and immunohistochemical changes in TM regions indicate different molecular mechanisms of TM damage in HPG and NTG.
• These findings highlight subtype-specific TM pathology in glaucoma.