Lymphatic and Blood Vessel Density in Human Conjunctiva Following Glaucoma Surgery

Abstract

Purpose: To investigate the lymphatic vascular microvessel density (LVD) and the blood vascular microvessel density (MVD) and their distribution in excised leaking blebs after mitomycin C (MMC) trabeculectomy and normal conjunctiva specimens.

Methods: LVD and MVD in normal human conjunctiva (n=7) and excised blebs in the hypocellular stroma and peribleb tissue (conjunctiva adjacent to hypocellular bleb tissue, n=7) was evaluated by immunohistochemistry using antibodies raised against Lymphatic Vessel Endothelial Receptor 1 (LYVE-1, lymphatic vessels) and CD34 (blood vessels). LVD and MVD counts were performed by light microscopy in 5 fields at 20X magnification by three observers. Differences were determined using Mann Whitney U test (p<0.05 was considered significant).

Results: The LVD and MVD were significantly reduced to absent in the hypocellular conjunctival stroma of the excised blebs compared to normal conjunctiva (21.42 vs. 1.16, p<0.002 and 24.28 vs. 1, p< 0.008 respectively). The LVD and MVD was also reduced (2 to 2.5 fold) in the peribleb stroma when compared to normal conjunctiva specimens.

Conclusions: Reduced LCD and MVD in the hypocellular stroma and peribleb stroma may play a role in an altered immune response in leaking blebs leading to an increased risk of blebitis.

Keywords: 474 conjunctiva • 554 immunohistochemistry • 436 blood supply