Intraocular Pressure-Lowering Effects of Trabeculectomy Versus MicroShunt Insertion in Rabbit Eyes

Abstract

Purpose To compare the surgical results of PRESERFLO MicroShunt (MicroShunt) insertion and trabeculectomy in rabbit eyes. Methods Trabeculectomy or MicroShunt insertion was performed on the eyes of Japanese white rabbits. Intraocular pressure (IOP) was measured on conscious rabbits using a rebound tonometer for up to 12 weeks after surgery. Filtering bleb appearance was evaluated. Scarring in the filtering bleb was assessed by immunohistochemical analyses. The change in mRNA expression in the conjunctiva was evaluated using RNA sequence analyses. Results The preoperative IOP of the operative eye did not differ significantly between trabeculectomy (11.6 ± 1.0 mmHg, n = 10) and MicroShunt insertion (12.6 ± 1.3 mmHg, n = 10). In both groups, the IOP of the operative eye was significantly lower than that of the contralateral eye at one day postoperatively, which continued until 12 weeks after surgery. The peak differences in IOP were −8.4 ± 3.0 (trabeculectomy) and −8.1 ± 2.1 mmHg (MicroShunt) at two weeks after surgery; no significant differences were observed in IOP reduction between the groups. Appearance and immunohistochemical analyses of the filtering bleb showed no significant difference between the groups. Moreover, RNA sequence analysis results showed no difference between the groups in mRNA expression fluctuations. Conclusions Postoperative IOP, bleb appearance, and immunohistochemical analysis results were similar in the trabeculectomy and MicroShunt groups, indicating that MicroShunt insertion is as effective as trabeculectomy in lowering IOP. Translational Relevance Comparison of surgical procedures using animal models has made it possible to predict clinical efficacy and safety.

Tissue Reactivity to, and Stability of, Glaucoma Drainage Device Materials Placed Under Rabbit Conjunctiva

“…Immunostaining was performed as described previously. 16 Enucleated eyes were fixed in Super Fix (Kurabo, Osaka, Japan) overnight at 4°C and then soaked in 30% (w/v) sucrose (FUJIFILM Wako Pure Chemical Corporation, Osaka, Japan) for 48 hours at 4°C. The eyes were dissected to obtain the entire incisional areas and embedded in an optimal-cutting-temperature compound (Sakura Finetek, Torrance, CA).…”

“… 11 – 13 Recently, the PreserFlo MicroShunt drainage device, fabricated entirely of SIBS, has become available, and IOP-lowering effects have been reported in both clinical and basic research studies. 14 – 16 The PreserFlo MicroShunt is highly biocompatible and would be expected to minimize postoperative fibrosis. Although the inflammatory responses to various materials used to prepare glaucoma drainage devices have been investigated, 11 , 17 – 19 the effects on surrounding tissues of most materials used to fabricate modern glaucoma drainage devices have not been examined; such devices include those made from SIBS (the PreserFlo MicroShunt), silicone (large-plate glaucoma implants), stainless steel (the EX-PRESS Glaucoma Filtration Device), and glutaraldehyde cross-linked collagen (GACLC; the XEN Gel Stent).…”

The use of polyisobutylene-based polymers in ophthalmology

“…The clinical course is reviewed in detail by Pinchuk et al [ 27 ] and in the book by Sng and Barton [ 18 ]. A recent comparison of the MicroShunt with trabeculectomy in the rabbit model was published by Fujimoto et al [ 28 ].…”

Gene Expression Data for Investigating Glaucoma Treatment Options and Pharmacology in the Anterior Segment, State-of-the-Art and Future Directions

“…As described, another case of glaucoma-related fibrosis happens after glaucoma surgery (e.g., trabeculectomy), and here, tenon fibroblasts are most often implicated; these are considered to be part of the conjunctiva. In this context, RNA-seq gene expression data (for rabbit) in a time series after trabeculectomy are reported by GSE156781 ( Fujimoto et al, 2021 ); RNA was isolated from rabbit conjunctiva , including filtering blebs. Of note, not found in GEO is a matching mouse dataset ( Adachi et al, 2020 ), where the glaucoma filtration surgery model consisted of an incision of the limbal conjunctiva, followed by the insertion of a 33G needle tip into the anterior chamber, and 11–0 nylon sutures; RNA was taken from bleb region tissue and compared to control conjunctiva.…”