Assessment of a self-assembling peptide gel, SPG-178, in providing a clear operative field for trabeculectomy surgery for glaucoma in an animal model

Abstract

The presence of blood during ophthalmic surgery is problematic, as it can obstruct a surgeon's view of the operative field. This is particularly true when performing trabeculectomy surgery to enhance ocular fluid outflow and reduce intraocular pressure as a treatment for glaucoma, one of the most common vision loss conditions worldwide. In this study, we investigated the performance of a transparent, selfassembling peptide gel (SPG-178) and its ability to maintain visibility during trabeculectomy surgery. Unlike the hyaluronic acid gel commonly used in ophthalmic surgery, SPG-178 did not permit the ingress of blood into the gel itself. Rather, it forced blood to flow peripherally to the gel. Moreover, if bleeding occurred under the SPG-178 gel, perfusion with saline was able to effectively flush the blood away along the interface between the SPG-178 and the ocular tissue (in this case scleral) to clear the surgical field of view. In experimental trabeculectomy surgeries with mitomycin C used as an adjuvant, there were no differences in the postoperative recovery of intraocular pressure or bleb morphology with or without the use of SPG-178. SPG-178, therefore, when used in a gel formulation, represents a new material for use in intraocular surgery to ensure a clear operative field with likely beneficial treatment outcomes.

Can bleeding in trabeculectomy be decreased? Effectiveness of brimonidine pre-treatment

“…7,8 A self-assembling peptide gel (SPG-178) molecule, not requiring thermo-coagulation or cautery use, has recently been reported to provide a good surgical field visibility without hemorrhage during trabeculectomy in an animal model. 6 Although SPG-178 provided a clear and good intraoperative field during trabeculectomy in the animal model, its possible side effects and long-term outcomes in the anterior chamber are unknown. 6…”

“…6 Although SPG-178 provided a clear and good intraoperative field during trabeculectomy in the animal model, its possible side effects and long-term outcomes in the anterior chamber are unknown. 6…”

“…7,8 A selfassembling peptide gel (SPG-178) molecule, not requiring thermo-coagulation or cautery use, has recently been reported to provide a good surgical field visibility without hemorrhage during trabeculectomy in an animal model. 6 Although SPG-178 provided a clear and good intraoperative field during trabeculectomy in the animal model, its possible side effects and long-term outcomes in the anterior chamber are unknown. 6 Another agent used for bleeding control, brimonidine, a third-generation selective alpha-2 adrenergic agonist, is a vasoconstrictor that binds to alpha-2 adrenergic receptors 1000 times more than alpha-1 adrenergic receptors.…”

“…Because many arterioles are present in the eye, attempts at hemostasis have achieved limited success. 6 Techniques such as thermo-coagulation can have detrimental effects on the surgery. 7,8…”

“…Because many arterioles are present in the eye, attempts at hemostasis have achieved limited success. 6 Techniques such as thermo-coagulation can have detrimental effects on the surgery. 7,8 Trabeculectomy has been the optimum approach for glaucoma surgery for years due to its excellent intraocular pressure (IOP) lowering effect; however, it is highly invasive as the conjunctiva, sclera, trabecular meshwork, and iris are incised, altering the aqueous humor circulation to a great extent.…”