Pro-inflammatory cytokines in glaucomatous aqueous and encysted Molteno implant blebs and their relationship to pressure.

Purpose: To ascertain the presence of additional pro-inflammatory cytokines in glaucomatous aqueous, and their relationship with IOP.

Methods: To quantify the levels of 23 pro-inflammatory cytokines, and correlate levels with IOP, aqueous humor samples were analyzed from 23 eyes with open angle glaucoma (OAG) undergoing glaucoma filtration procedures, and from 24 Molteno blebs during the hypertensive phase. Control aqueous was derived from 13 eyes without glaucoma undergoing cataract removal.

Results: A significant difference (P<0.05) was noted between hypertensive bleb aqueous and controls in the amount TGF-β2, interleukins IL-6, IL-10, and chemokine (C-X-C motif) ligand 1 (CXCL1; GROα). The levels of these cytokines were higher in the glaucomatous aqueous, but not significantly so. A significant difference was noted in levels of chemokine (C-C motif) ligand 2 (CCL2; MCP-1, monocyte chemotactic protein-1) in the glaucoma eye and bleb aqueous compared with controls. Of the 23 cytokines tested for, 19 were found in the bleb group, 14 in the glaucoma group, and 16 in the control group. Compared with controls, all cytokines levels were higher in the glaucoma group and highest in the bleb group.

Conclusions: The study confirms the well documented presence of TGF-β2 in glaucomatous aqueous. The presence of significant levels of CCL2 in glaucomatous aqueous is a new finding. The finding of higher levels of all the cytokines in the aqueous from the encysted blebs, in which the IOP was the highest, suggests that their levels increase with an increase in IOP, as well as the possibility that encysted blebs form cytokines.