Abstract
Purpose:
Bleb-fibrosis causes glaucoma filtration surgery (GFS) failure due to excessive wound healing by TGFβ. Decorin, a small leucine-rich proteoglycan, is a natural inhibitor of TGFβ. We tested the hypothesis that decorin-PEI nanoparticles’ intraoperative application would block TGFβ hyperactivity, thus attenuate the excessive fibrosis and increase the bleb survival
Methods:
Six New Zealand White rabbits were used for GFS. Bleb was made by creating a conjunctival flap over 2 mm2 sclerotomy. Decorin palsmid-PEI nanoconstruct (n=3) or balanced saline solution (n=3) was administered in rabbit eye intra-operatively via subconjunctival injection. Slit lamp biomicroscopy, clinical eye exams, and intraocular pressure (IOP) measurements with tonometer were performed on day 0, 3, 7 and 14 after the surgery. The stereomicroscopy quantified bleb size and vascularity (score 1-4). On postoperative day-14, eyes were enucleated and snap frozen in optimal cutting temperature medium after euthanasia. Serial sections of eye tissues were prepared and stained for H&E, α-smooth muscle actin (SMA; myofibroblast marker) and f- actin (activated fibroblast marker).
Results:
The rabbits receiving decorin gene delivery by nanoparticles exhibited significantly reduced bleb fibrosis compared to vehicle-treated controls (p<0.01). The increased bleb survival by decorin-PEI was evidenced by the significant increase in bleb-length and area (p<0.01), and decrease in bleb-vascularity (p<0.05). Decorin-PEI treated rabbit eyes exhibited lower IOP than controls. H&E histology revealed a notable decrease in fibrosis in large area of the bleb. Immunofluorescence analysis of serial sections demonstrated remarkably decreased SMA+ and F-actin+ cells in the bleb. No damage, pathology and/or adverse effects were noted in the rabbit eyes of each group
Conclusions:
The intraoperative subconjunctival decorin-PEI injection significantly decreased fibrosis and increased bleb survival. Nanoparticle-mediated decorin gene therapy has potential to enhance bleb survival and provide long-term glaucoma management. More in vivo rabbit studies are warranted.