Pathobiology of wound healing after glaucoma filtration surgery

Visualization of Scleral Flap Patency in Glaucoma Filtering Blebs Using OCT

Purpose

To investigate the use of anterior-segment OCT (AS-OCT) to visualize the aqueous outflow pathway and patency of the scleral flap in glaucoma filtration surgery blebs.

Design

Cross-sectional study.

Subjects

Two hundred five filtering blebs of 112 patients with glaucoma who had undergone trabeculectomy (Trab, n = 97) or deep sclerectomy (DS, n = 108) surgery with/without mitomycin-C (MMC).

Methods

Swept-source AS-OCT raster slices were used to image the Trab and DS blebs in sagittal and coronal planes using a standardized protocol. Bleb appearances were classified into 4 categories based on the scleral flap and sclerostomy/trabeculo-descemet window (TDW) appearance: A-sclerostomy/TDW not visible; B-sclerostomy/TDW visible but scleral flap indiscriminate from sclera; C-scleral flap distinct but edges adherent to surrounding sclera; D-scleral flap edges non adherent to surrounding sclera.

Main Outcome Measures

Surgical outcomes were classified into complete success (CS) (intraocular pressure [IOP] ≤18 mmHg with no medications), qualified success (QS) (IOP ≤18 with medications), and failure (F) (IOP >18 mmHg).

Results

The proportions of CS, QS, and F in the Trab and DS cohorts were 45.0% and 29.6%, 33.0% and 31.5%, 22.0% and 38.9% respectively, with a median postoperative follow-up of 8.4 years (standard deviation 7.9; interquartile range 3.2-9.0). In QS and failed blebs, category C (Trab, 53.7%; DS, 52.5%) accounted for the majority of scleral flap appearances, followed by categories A and B. Category D (86.0%; 71.9%) accounted for the majority of appearances in Trab and DS blebs with CS. There was a significantly greater proportion of MMC use in categories C and D compared with categories A and B in both Trab (P < 0.0001) and DS (P = 0.02) cohorts, demonstrating the association of intraoperative MMC use with increased patency of the scleral flap.

Conclusions

Swept-source AS-OCT may be used to visualize the position and patency of the sclerostomy/TDW and scleral flap in relation to surrounding structures in both sagittal and coronal planes. Although free scleral flap edges are primarily correlated with MMC use, it may also correlate with surgical success. Anterior-segment OCT may be used to complement subjective bleb grading at the slit lamp in the assessment of filtering blebs.

Financial Disclosures

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

The Effect of Prostaglandin F2 Analog Treatment on the Immunoexpression of Fibrosis-Associated Factors in Patients with Glaucoma Undergoing Deep Sclerotomy

Long-term use of topical prostaglandins might initiate chronic conjunctival inflammation, leading to poor outcomes of glaucoma surgery. The aim of this study was to evaluate the immunoexpression pattern of HSP70, CTGF, SNAIL, aSMA, cMYB, and HIFa in the conjunctiva, episclera, and deep sclera in patients with glaucoma undergoing deep sclerectomy in order to establish an association between staining intensities and prostaglandin F2 (PGF2) treatment. Double immunofluorescence (HSP70, CTGF, SNAIL, aSMA, cMYB, and HIFa) was performed on conjunctiva, episclera, and deep sclera samples, which were obtained from 23 patients treated with PGF2 and 8 patients without PGF2 treatment. When comparing the ocular tissues of patients regarding treatment with PGF2 analogs, we found a significant increase in the immunoexpression of HSP70 in the conjunctival epithelium of patients treated with PGF2 analogs compared to those without PGF2 treatment. These patients also had an increase in SNAIL immunoexpression and a decrease in aSMA immunoexpression in the deep sclera. There were no significant differences in HIFa, CTGF, or cMYB immunoexpression levels between the two groups. Further research into the regulation of these factors in ocular tissues could lead to the development of potential novel therapeutic approaches in glaucoma management.

Efficacy and Safety of PreserFlo MicroShunt Implantation and Its Effects on Intraocular Inflammation through Laser Flare Photometry

Purpose

The primary objective of this study is to evaluate the efficacy and safety profile of PreserFlo MicroShunt implantation in the medium- to long-term follow-up of patients with open-angle glaucoma. The secondary objective is to analyze laser flare meter (LFM) values before and after PreserFlo MicroShunt implantation.

Methods

This prospective, observational, longitudinal single-center study included a total of 62 eyes from 54 patients. A subgroup of 27 eyes (26 patients) reached the 12-month follow-up. Success was defined based on three criteria: criterion A: IOP ≤21 mmHg and ≥20% reduction; criterion B: IOP ≤15 mmHg and ≥25% reduction; and criterion C: IOP ≤12 mmHg and ≥30% reduction. Success was further categorized as complete if achieved without IOP-lowering medications and qualified if achieved with medication administration. Other aspects evaluated included the number of IOP-lowering medications (baseline and postoperative), development of postoperative complications, 5-FU injections or implant revision, and LFM values.

Results

The 12-month follow-up group (27 patients) was composed by 50% males and had a mean age of 75.54 ± 9.98 years. Success rates at 12 months were as follows: 78% for criterion A, 56% for criterion B, and 26% for criterion C. Complete success, as defined by criterion A, was achieved by 67% of the patients, 29% achieved qualified success, and one eye (4%) experienced failure. IOP decreased from 25.26 ± 1.67 mmHg at baseline to 14.81 ± 0.74 mmHg at 12 months. The number of medications decreased from 3.67 ± 1.30 at baseline to 0.48 ± 0.75 at 12 months. Reported complications were choroidal detachment (11%), hyphema (5%), and athalamia (flat anterior chamber) (2%) 13 eyes (48%) received 5-FU injections, while 7 eyes (26%) underwent implant revision. No significant increase in LFM values was observed. Eyes with a regular postoperative course and IOP ≤15 mmHg showed significantly lower LFM values than patients with unfavorable outcomes (IOP >15 mmHg, development of complications, 5-FU injection, or implant revision).

Conclusions

PreserFlo MicroShunt showed a significant reduction in IOP and a decrease in the number of IOP-lowering medications. Complications occurred at a modest frequency. The implant provides a minimally invasive approach with no significant increases in LFM values postoperatively. Higher LFM values correlate with unfavorable postoperative outcomes.

Genome-wide RNA sequencing of ocular fibroblasts from glaucomatous and normal eyes: Implications for glaucoma management

Primary open angle glaucoma is a leading cause of visual impairment and blindness which is commonly treated with drugs or laser but may require surgery. Tenon's ocular fibroblasts are involved in wound-healing after glaucoma filtration surgery and may compromise a favourable outcome of glaucoma surgery by contributing to fibrosis. To investigate changes in gene expression and key pathways contributing to the glaucomatous state we performed genome-wide RNA sequencing. Human Tenon's ocular fibroblasts were cultured from normal and glaucomatous human donors undergoing eye surgery (n = 12). mRNA was extracted and RNA-Seq performed on the Illumina platform. Differentially expressed genes were identified using a bioinformatics pipeline consisting of FastQC, STAR, FeatureCounts and edgeR. Changes in biological functions and pathways were determined using Enrichr and clustered using Cytoscape. A total of 5817 genes were differentially expressed between Tenon's ocular fibroblasts from normal versus glaucomatous eyes. Enrichment analysis showed 787 significantly different biological functions and pathways which were clustered into 176 clusters. Tenon's ocular fibroblasts from glaucomatous eyes showed signs of fibrosis with fibroblast to myofibroblast transdifferentiation and associated changes in mitochondrial fission, remodeling of the extracellular matrix, proliferation, unfolded protein response, inflammation and apoptosis which may relate to the pathogenesis of glaucoma or the detrimental effects of topical glaucoma therapies. Altered gene expression in glaucomatous Tenon's ocular fibroblasts may contribute to an unfavourable outcome of glaucoma filtration surgery. This work presents a genome-wide transcriptome of glaucomatous versus normal Tenon's ocular fibroblasts which may identify genes or pathways of therapeutic value to improve surgical outcomes.

Healing responses at the angle after micro-invasive glaucoma surgery-an AS-OCT study

PURPOSE

To evaluate structural alterations and healing responses in the trabecular meshwork region with optical coherence tomography (AS-OCT) following after gonioscopy assisted transluminal trabeculotomy (GATT) and microincisional trabeculectomy (MIT).

METHODS

73 eyes of 67 patients (M:F = 45:22) with ≥6 months of follow-up after MIT (n = 41) or GATT (n = 32) with or without combined cataract surgery were included for this prospective study. The angle as seen on AS-OCT at 1, 3, 6 months after surgery were evaluated for structural alterations like peripheral anterior synechiae (PAS), hyphema, and hyperreflective scarring responses. The scarring was graded according to the linear extent measured from the centre of the trabecular meshwork (TM) gutter to the sclera/cornea as mild (<250μ), moderate (250-500μ), and severe(˃500μ), while the pattern of scarring was graded as open saucer/gutter, closed gutter, and trench pattern. The association of the need for medication or surgical outcome and clinical variables and AS-OCT parameters including the pattern and severity of scarring were analysed using multivariate regression.

RESULTS

All eyes achieved significant reduction of IOP and number of medications with a final IOP of 15±3.2mm Hg at a mean follow-up of 8±32. months. While mild scarring was seen more common in MIT, severe scarring was seen in >65% of GATT eyes compared to 31% of MIT eye, p<0.001. An open saucer was equally seen in MIT and GATT while the trench pattern was more commonly seen in GATT eyes (>50%). Severe scarring in a trench pattern seemed to predict the need for medications for IOP control, though they independently did not seem to influence the final IOP or surgical outcome.

CONCLUSION

A severe form of scarring in a trench pattern on AS-OCT predicted the need for glaucoma medications after MIGS surgery. Regular monitoring of the scarring responses by AS-OCT and clinical examination are necessary to identify those at need for medications after MIGS.

Lysophosphatidic Acid Modulates TGF-β2-Induced Biological Phenotype in Human Conjunctival Fibroblasts

BACKGROUND

Although lysophosphatidic acid (LPA) is known to have multiple pathophysiological roles, its contributions to ocular tissues, especially conjunctival fibrogenesis, remain to be elucidated.

METHODS

To study this issue, the effects of LPA on transforming growth factor-β2 (TGF-β2)-induced fibrogenesis of two-dimensional (2D) and three-dimensional (3D) cultures of human conjunctival fibroblasts (HconF) were examined by the following analyses: (1) planar proliferation determined by transepithelial electrical resistance (TEER) and fluorescein isothiocyanate (FITC)-dextran permeability measurements, (2) real-time metabolic analyses, (3) measurements of the size and stiffness of 3D spheroids, and (4) mRNA expression of extracellular matrix (ECM) molecules and their modulators.

RESULTS

LPA had no effect on TGF-β2-induced increase in the planar proliferation of HconF cells. LPA induced a more quiescent metabolic state in 2D HconF cells, but this metabolic suppression by LPA was partially blunted in the presence of TGF-β2. In contrast, LPA caused a substantial decrease in the hardness of 3D HconF spheroids independently of TGF-β2. In agreement with these different LPA-induced effects between 2D and 3D cultured HconF cells, mRNA expressions of ECM and their modulators were differently modulated.

CONCLUSION

The findings that LPA induced the inhibition of both TGF-β2-related and -unrelated subepithelial proliferation of HconF cells may be clinically applicable.

Using a Novel, Subconjunctival, Sustained-Release Mitomycin C Formulation in a Rabbit Model of Filtration Surgery with Gel Stent Implantation

Purpose: To investigate gel stent implantation with and without intraoperative sustained-release mitomycin C (MMC SR) in a rabbit model for gel stent implantation, and to examine aqueous humor outflow (AHO) postimplantation. Methods: Four groups of rabbits were included. Group 1 was untreated (control). Groups 2, 3, and 4 received the gel stent without MMC, with MMC solution (subconjunctival injection), and with MMC SR (subconjunctival injection), respectively. Intraocular pressure (IOP) and AHO were assessed via tonometry and indocyanine green-based angiography, respectively. The main efficacy measure was change in IOP from baseline. Results: Following gel stent implantation, Groups 2, 3, and 4 maintained ≥20% IOP reduction (response) for a median duration of 1 week, 6.5 weeks, and 30 weeks, respectively. Angiography showed normal aqueous humor drainage (Group 1) beginning at the perilimbal trabecular plexus and continuing posteriorly to episcleral outflow vessels. Following implantation, drainage occurred preferentially and directly into the subconjunctival bleb. Conclusions: Gel stent implantation with MMC SR was most effective in achieving sustained, long-term IOP reduction in the rabbit model, compared with implantation with or without MMC solution. Bleb presence and the postimplantation aqueous angiography results indicated redirection of the AHO to the subconjunctival vasculature and presumed lymphatics, suggesting efficient glaucoma filtration to lower IOP in this model. This rabbit model and aqueous angiography may help refine understanding of the mechanism of action of minimally invasive glaucoma surgeries and ultimately translate to improved surgical devices and procedures for patients with glaucoma.

Anterior Segment Optical Coherence Tomography for Cases of High Intraocular Pressure Following XEN Implant for Glaucoma

PRCIS

This study showed that the XEN patency should be verified by OCT imaging in cases of encapsulated blebs. Although fibrosis plays the principal role, humor aqueous flow reduction could affect the "spacer" effect that inhibits the fibroblast attachments.

PURPOSE

To evaluate the application of the anterior segment optical coherence tomography (AS-OCT) imaging in studying the relationship between a low flow rate through the XEN63 and the development of a cystic bleb.

METHODS

Retrospective case series of 3 eyes presenting a cystic bleb after an XEN63 implantation for uncontrolled intraocular pressure (IOP). Demographic and clinical data were obtained from medical records. The imaging findings, complications, and managements following the surgery were evaluated.

RESULTS

Three patients, with an average age of 67.3 years, initially showed a patent stent lumen and a functional bleb after surgery. The IOP of all eyes increased on average at 28.3 days from the surgery, with a mean value of 39.66 mm Hg. The slit lamp examination showed a cystic bleb. The AS-OCT imaging confirmed the previous finding and revealed either a partial or total occlusion of the stent internal ostium. A Nd:YAG laser, in proximity to the ostium, was performed to resolve the obstruction. Although the AS-OCT imaging showed the device patency and the IOP immediately decreased, the latter became elevated again. Consequently, in all the cases, a further needling procedure was needed to achieve an adequate IOP reduction. Six months after the two-step procedure, the IOP averaged 13.33 mm Hg, the XEN63 lumens appeared cleared, and the blebs showed a functional morphology. No adverse events were observed.

CONCLUSION

The development of a cystic bleb may result from an altered balance between the flow rate through the XEN63 and the fibrosis development in the postoperative healing process. A proper follow-up based on slit lamp biomicroscopy, IOP measurement, and AS-OCT imaging is advisable to estimate and manage a cystic bleb following XEN63 implantation.

Wound Modulations in Glaucoma Surgery: A Systematic Review

Excessive fibrosis and resultant poor control of intraocular pressure (IOP) reduce the efficacy of glaucoma surgeries. Historically, corticosteroids and anti-fibrotic agents, such as mitomycin C (MMC) and 5-fluorouracil (5-FU), have been used to mitigate post-surgical fibrosis, but these have unpredictable outcomes. Therefore, there is a need to develop novel treatments which provide increased effectiveness and specificity. This review aims to provide insight into the pathophysiology behind wound healing in glaucoma surgery, as well as the current and promising future wound healing agents that are less toxic and may provide better IOP control.

Sulforaphane inhibits TGF-β-induced fibrogenesis and inflammation in human Tenon's fibroblasts

Purpose

Subconjunctival fibrosis is the main cause of failure after glaucoma filtration surgery. We explored the effects of sulforaphane (SFN) on the conversion of human Tenon's fibroblasts (HTFs) into myofibroblasts, transforming growth factor (TGF)-β-induced contraction of collagen gel, and inflammation.

Methods

After treatment with the combination of TGF-β and SFN or TGF-β alone, primary HTFs were subjected to a three-dimensional collagen contraction experiment to examine their contractility. Levels of α smooth muscle actin (α-SMA), synthesis of extracellular matrix (ECM), and phosphorylation of various signaling molecules were determined by western blot or quantitative reverse transcription-polymerase chain reaction (RT-qPCR). Fluorescence microscopy was employed to examine stress fiber formation in HTFs. The expressions of interleukin (IL)-6, IL-8, and connective tissue growth factor (CTGF) were determined using RT-qPCR.

Results

The contraction of myofibroblasts caused by TGF-β was significantly suppressed by SFN. This suppressive effect was exerted via the differentiation of HTFs into myofibroblasts by inhibiting the production of fibronectin and the expression of α-SMA. Moreover, SFN treatment reduced the expression of TGF-β-promoted integrins β1 and α5, myosin light chain (MLC) phosphorylation, and stress fiber formation, as well as the expression of IL-6, IL-8, and CTGF. Finally, TGF-β-induced Smad2/3 and extracellular signal-regulated kinase (ERK) phosphorylations were attenuated by SFN.

Conclusions

SFN inhibits HTF contractility, differentiation into myofibroblasts, and inflammation caused by TGF-β. These effects are mediated by both classic and non-classic signaling pathways. Our results indicate that SFN has potent anti-fibrotic and anti-inflammatory effects in HTFs and is a potential candidate for subconjunctival fibrosis therapy.

[Perioperative prevention of bleeding in glaucoma surgery]

PURPOSE

This study assesses the impact of preoperative administration of Oku-Oku eye drops on the severity of conjunctival hyperemia and the risk of hemorrhagic complications in the early postoperative period following glaucoma surgery.

MATERIAL AND METHODS

The study included a group of 30 patients (30 eyes) with uncontrolled primary open-angle glaucoma who underwent non-penetrating deep sclerectomy. The main group included 15 eyes, in which Oku-Oku drops were administered twice - on the day before surgery (upon hospital admission) and immediately before the operation. The control group consisted of 15 eyes that underwent surgery without additional medications. Intraocular pressure (IOP) and conjunctival hyperemia were measured before and after surgery. The duration of coagulation during surgery was also recorded. The rate of hemorrhagic complications was compared between the groups.

RESULTS

The performed glaucoma surgery significantly reduced IOP in both groups, with no significant differences in postoperative IOP levels. Conjunctival hyperemia increased in both groups postoperatively, though the increase was slightly less in the main group. There was a significant difference in the duration of scleral vessel coagulation in the surgical area, amounting to 3.8±2.6 seconds in the main group and 6.9±3.0 seconds in the control group. Hemorrhagic complications occurred less frequently in the main group.

CONCLUSION

Preoperative use of Oku-Oku eye drops reduced the severity of conjunctival hyperemia and the width of scleral vessels. The reduction in hemorrhagic complications in the early postoperative period may contribute to decreased scarring. Oku-Oku can be included in the comprehensive preoperative preparation for glaucoma surgery and other procedures with a risk of bleeding. Further research is needed to evaluate the effectiveness of Oku-Oku in the perioperative period.

Sulforaphane inhibits TGF-β-induced fibrogenesis and inflammation in human Tenon's fibroblasts

Purpose

Subconjunctival fibrosis is the main cause of failure after glaucoma filtration surgery. We explored the effects of sulforaphane (SFN) on the conversion of human Tenon's fibroblasts (HTFs) into myofibroblasts, transforming growth factor (TGF)-β-induced contraction of collagen gel, and inflammation.

Methods

After treatment with the combination of TGF-β and SFN or TGF-β alone, primary HTFs were subjected to a three-dimensional collagen contraction experiment to examine their contractility. Levels of α smooth muscle actin (α-SMA), synthesis of extracellular matrix (ECM), and phosphorylation of various signaling molecules were determined by western blot or quantitative reverse transcription-polymerase chain reaction (RT-qPCR). Fluorescence microscopy was employed to examine stress fiber formation in HTFs. The expressions of interleukin (IL)-6, IL-8, and connective tissue growth factor (CTGF) were determined using RT-qPCR.

Results

The contraction of myofibroblasts caused by TGF-β was significantly suppressed by SFN. This suppressive effect was exerted via the differentiation of HTFs into myofibroblasts by inhibiting the production of fibronectin and the expression of α-SMA. Moreover, SFN treatment reduced the expression of TGF-β-promoted integrins β1 and α5, myosin light chain (MLC) phosphorylation, and stress fiber formation, as well as the expression of IL-6, IL-8, and CTGF. Finally, TGF-β-induced Smad2/3 and extracellular signal-regulated kinase (ERK) phosphorylations were attenuated by SFN.

Conclusions

SFN inhibits HTF contractility, differentiation into myofibroblasts, and inflammation caused by TGF-β. These effects are mediated by both classic and non-classic signaling pathways. Our results indicate that SFN has potent anti-fibrotic and anti-inflammatory effects in HTFs and is a potential candidate for subconjunctival fibrosis therapy.

All Consecutive Ab Externo SIBS Microshunt Implantations With Mitomycin C: One-Year Outcomes and Risk Factors for Failure

PURPOSE

To present the effectiveness, risk factors for surgical failure, and adverse events over 12 months in a consecutive diverse cohort of glaucoma patients who underwent solo or combined ab externo SIBS microshunt with mitomycin C (MMC) with or without previous subconjunctival surgery.

DESIGN

Retrospective, consecutive, interventional case series.

METHODS

Consecutive glaucomatous eyes on maximally tolerated medical therapy received ab externo SIBS microshunt with MMC implantation as a solo or combined procedure with phacoemulsification from July 2015 to January 2020. The primary outcome was the proportion of eyes at 12-months with the following: (1) no 2 consecutive intraocular pressures (IOPs) >17 mm Hg or clinical hypotony, without (complete success) or with (qualified success) glaucoma medications; and (2) ≥20% reduction from baseline IOP. Secondary outcomes included upper IOP thresholds of 14 and 21 mm Hg with and without a 20% IOP reduction from baseline, median IOP, medications, risk factors for failure, postoperative interventions, complications, and reoperations.

RESULTS

A total of 436 eyes underwent surgery; 86 (20%) combined with phacoemulsification, 127 (29%) in eyes with refractory glaucoma, and 234 (51%) stand-alone procedures in non-refractory eyes. Complete success (6-17 mm Hg with no medications) was achieved in 64.0% of combined eyes, 58.1% of refractory eyes, and 74.8% of stand-alone non-refractory eyes; and qualified success rates (6-17 mm Hg with medications) were 90.7%, 84.7%, and 92.4% of eyes, respectively. At 12 months, 67% of eyes were medication free. Significant risk factors for failure included combined procedures in refractory eyes (hazard ratio [HR] = 3.2; 95% CI = 1.4-7.4), receiving <0.4 mg/mL of MMC (HR = 2.2; 95% CI = 1.6-3.1), refractory eyes (HR = 1.7; 95% CI = 1.2-2.5), combined procedures (HR = 1.6; 95% CI = 1.0-2.5), and each additional baseline medication class (HR = 1.3; 95% CI = 1.1-1.5). Postoperative complications occurred in 31% of eyes, and more often in those receiving ≥0.4 mg/mL MMC (odds ratio [OR] = 2.2, 95% CI 1.2-3.8). Needling occurred in 12% of eyes, with significantly higher frequency in refractory eyes (23%) and combined procedures (13%) compared to stand-alone (7%; P < .001). Revisions and reoperations occurred in 4% and 1.4% of eyes, respectively.

CONCLUSIONS

The 1-year follow-up data from this large and diverse cohort support promising rates of qualified and complete surgical success with decreased medication burden and few postoperative complications and interventions. Combined phacoemulsification, refractory glaucoma, and receiving <0.4mg/mL MMC were associated with reduced surgical success rates.

Role of the chloride channel blocker in the formation of filtering tract scars after glaucoma surgery in rats

Filtration surgery is commonly performed for glaucoma treatment to reduce intraocular pressure (IOP); however, scarring of the filtering bleb is the main cause of failure. In this study, we evaluated the effects of the chloride channel blocker 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) on scar formation in filtering blebs. A glaucoma filtering surgery model was generated using Sprague-Dawley rats, divided into the control and NPPB groups receiving injections of different NPPB concentrations. The IOP of all rats decreased 1-day post-surgery and gradually increased afterward. However, IOP in rats from the NPPB groups recovered more slowly than that of the control group rats. In addition, the area and survival times of filtering blebs in rats from the NPPB groups were substantially larger and longer than those in the control group. Twenty-eight days after surgery, the protein and mRNA expression of collagen I, fibronectin and α-smooth muscle actin in the filtering area of rats from the NPPB groups were significantly lower than that in the control group rats. Collectively, our study demonstrates that NPPB inhibits filtering bleb scar formation, maintains filtering bleb morphology and prolongs filtering bleb survival time by inhibiting the differentiation of conjunctival fibroblasts and extracellular matrix synthesis.

Analysis of the impact of different schemes of preparation to trabeculectomy on the healing markers on the Tenon fibroblasts cultures

The aim of the study was to assess the influence of different regimes of patient's preparation before trabeculectomy on the markers of healing process in Tenon's fibroblast cultures.The studied group consisted of 66 patients with open angle glaucoma undergoing primary trabeculectomy. The patients were divided into 5 groups with different regimes of preparation before the surgery based on application or withdrawal of topical antiglaucoma medications and steroids (G1-patients using antiglaucoma drops until the day of the surgery; G2-patients using antiglaucoma drops until the day of the surgery and additionally dexamethasone for 4 weeks before surgery; G3-patients who stopped using antiglaucoma drops 4 weeks before the surgery and introduced dexamethasone for 4 weeks before surgery; G4-patients who stopped using antiglaucoma drops 4 weeks before the surgery; G5-control group, patients with newly diagnosed glaucoma in whom trabeculectomy was the first treatment option without medical treatment). During trabeculectomy the samples of Tenon's capsule were obtained. Tenon fibroblasts were isolated directly from the explants to test their proliferation ability and the level of released healing markers. Following factors typical of healing process were evaluated using commercially available ELISA kits: IL 1-β, IL-6, IL-8, VEGF-A, TGF-β1 and MMP-9. Concentrations of IL-1β, IL-6 and TGF-β1 were significantly higher in the group obtaining antiglaucoma drops. Additionally, in this group the fibroblasts revealed the highest proliferation potential, indicating the active healing process. The levels of IL-8, VEGF-A and MMP-9 were similar between the groups. Our study shows that for the best conjunctival anti-inflammatory control, the most influential factor is the withdrawal of antiglaucoma medications.

Effects of Ripasudil, a Rho-Kinase Inhibitor, on Scar Formation in a Mouse Model of Filtration Surgery

PURPOSE

Glaucoma is a leading cause of blindness worldwide. Characteristic changes occur in the optic nerve and visual field of patients with glaucoma; optic nerve damage can be mitigated by lowering intraocular pressure. Treatment modalities include drugs and lasers; filtration surgery is necessary for patients with insufficient intraocular pressure reduction. Scar formation often contributes to glaucoma filtration surgery failure by increasing fibroblast proliferation and activation. Here, we examined the effects of ripasudil, a Rho-associated protein kinase (ROCK) inhibitor, on postoperative scar formation in human Tenon's fibroblasts.

METHODS

Collagen gel contraction assays were used to compare contractility activity among ripasudil and other anti-glaucoma drugs. The effect of Ripasudil in combination with other anti-glaucoma drugs and transforming growth factor-β (TGF-β), latanoprost and timolol-induce contractions were also tested in this study. Immunofluorescence and Western blotting were used to study the expression of factors relating scarring formation.

RESULTS

Ripasudil inhibited contraction in collagen gel assay and reduced α-smooth muscle actin (SMA) and vimentin (scar formation-related factors) expression, which was inversely promoted by latanoprost, timolol or TGF-β. Ripasudil also inhibited contraction on TGF-β, latanoprost and timolol-induced contraction. Furthermore, we investigated the effects of ripasudil on postoperative scarring in a mouse model; ripasudil suppressed postoperative scar formation by altering the expression of α-SMA and vimentin.

CONCLUSIONS

These results suggest that ripasudil, ROCK inhibitor may inhibit excessive fibrosis after glaucoma filtering surgery vis inhibition the transdifferentiation of tenon fibroblast into myofibroblast and may have a potential effect as anti-scarring for glaucoma filtration surgery.

Treatment of filtration bleb dysfunction after glaucoma surgery by needle revision of filtration bleb combined with conbercept

Filtration surgery (Trabeculectomy) is the main treatment for glaucoma. The scarring of the filtration bleb and obstruction of the outflow of aqueous humor through the filtration channel are the main reasons of the surgery failure. The objective of this study was to determine the clinical efficacy of needle revision of filtration blebs combined with subconjunctival injection of conbercept on the functional bleb formation in glaucoma patients with eye pressure out of control after trabeculectomy. A total of 48 eyes with poor filtration bleb function after trabeculectomy for glaucoma were treated with needle revision of filtration bleb combined with subconjunctival injection of conbercept. After the treatment, the patients were followed up for 3 months during which visual acuity, intraocular pressure, slit lamp and ultrasound biomicroscope examinations were performed. Intraoperative and postoperative complications were recorded. The visual acuity and intraocular pressure were significantly improved after the needle revision of filtration blebs. Among the 48 eyes, 39 eyes still had functional blebs at the end of the follow-up period, and filtration blebs failed in 9 eyes 2 to 8 weeks after the removal of the needle. The survival rate of filtration blebs at 3 months after needle revision was (79.06 ± 3.42%), and 81.25% (39/48) of the eyes showed good formation rate of functional bleb at the last follow-up. Three months after needle revision, there was local scar formation in some filtration blebs. Part of the filtration blebs showed mild thickening of the local subconjunctival tissue, and the filtration bleb was slightly raised and diffuse, showing a multi-cavity and thin-walled shape in some blebs. Ultrasound biomicroscopy examination showed relative structural manifestations. Subconjunctival hemorrhage occurred in 43 patients during and after the operation. Low intraocular pressure occurred in 8 patients with the lowest pressure of 5 mm Hg. Choroidal edema was observed in 3 patients. Five patients had intraoperative conjunctival hemorrhage in the anterior chamber, and hyphema occurred. All complications were self-limited and resolved without surgical intervention. Needle revision of filtration bleb combined with anti-VEGF drugs is a safe and effective method for the treatment of filtration bleb dysfunction after surgery of glaucoma.

The Role of STAT3 Signaling Pathway Activation in Subconjunctival Scar Formation after Glaucoma Filtration Surgery

Scar formation resulting from overly active wound healing is a critical factor in the success rate of glaucoma filtration surgery (GFS). IL-6 and TGF-β have been implicated in the pathogenesis of fibrogenesis. In addition, the signal transducer and activator of transcription 3 (STAT3) can be activated by numerous cytokines and growth factors, including IL-6 and TGF-β1. Thus, STAT3 activation may integrate common profibrotic pathways to promote fibrosis. In this study, an increase in p-STAT3 was observed in activated HTFs. Inhibiting STAT3 in cultured HTFs by pharmacological inactivation reversed the fibrotic responses, such as fibroblast migration, the differentiation of resting fibroblasts into myofibroblasts and the deposition of ECM, mediated by IL-6 and TGF-β1. Moreover, the expression of suppressor of cytokine signaling 3 (SOCS3) was decreased in HTFs cultured with IL-6 and TGF-β1, and SOCS3 overexpression rescued ECM deposition, α-SMA expression and migration in IL-6- and TGF-β1-stimulated HTFs by inactivating STAT3. Finally, S3I-201 treatment inhibited profibrotic gene expression and subconjunctival fibrosis in a rat model of GFS. In conclusion, our data suggests that STAT3 plays a central role in fibrosis induced by different profibrotic pathways and that STAT3 is a potential target for antifibrotic therapies following GFS.

Differential Gene and Protein Expression of Conjunctival Bleb Hyperfibrosis in Early Failure of Glaucoma Surgery

The early failure of glaucoma surgery is mainly caused by over-fibrosis at the subconjunctival space, causing obliteration of the filtration bleb. Because fibrosis has a suspected basis of genetic predisposition, we have undertaken a prospective study to identify upregulated profibrotic genes in a population of glaucoma patients with signs of conjunctival fibrosis and early postoperative surgical failure. Clinical data of re-operated fibrosis patients, hyperfibrosis patients who re-operated more than once in a short time, and control patients with no fibrosis were recorded and analyzed at each follow-up visit. Conjunctival-Tenon surgical specimens were obtained intraoperatively to evaluate the local expression of a panel of genes potentially associated with fibrosis. In order to correlate gene expression signatures with protein levels, we quantified secreted proteins in primary cultures of fibroblasts from patients. Expression of VEGFA, CXCL8, MYC, and CDKN1A was induced in the conjunctiva of hyperfibrosis patients. VEGFA and IL8 protein levels were also increased in fibroblast supernatants. We propose that an increase in these proteins could be useful in detecting conjunctival fibrosis in glaucoma patients undergoing filtering surgery. Molecular markers could be crucial for early detection of patients at high risk of failure of filtration surgery, leading to more optimal and personalized treatments.

Adrenaline blocks key cell cycle genes and exhibits antifibrotic and vasoconstrictor effects in glaucoma surgery

Adrenaline is a sympathomimetic drug used to maintain pupil dilation and to decrease the risk of bleeding. The aim of this study was to demonstrate if adrenaline could exert antifibrotic effects in glaucoma surgery. Adrenaline was tested in fibroblast-populated collagen contraction assays and there was a dose-response decrease in fibroblast contractility: matrices decreased to 47.4% (P = 0.0002) and 86.6% (P = 0.0036) with adrenaline 0.0005% and 0.01%, respectively. There was no significant decrease in cell viability even at high concentrations. Human Tenon's fibroblasts were also treated with adrenaline (0%, 0.0005%, 0.01%) for 24 h and RNA-Sequencing was performed on the Illumina NextSeq 2000. We carried out detailed gene ontology, pathway, disease and drug enrichment analyses. Adrenaline 0.01% upregulated 26 G1/S and 11 S-phase genes, and downregulated 23 G2 and 17 M-phase genes (P < 0.05). Adrenaline demonstrated similar pathway enrichment to mitosis and spindle checkpoint regulation. Adrenaline 0.05% was also injected subconjunctivally during trabeculectomy, PreserFlo Microshunt and Baerveldt 350 tube surgeries, and patients did not experience any adverse effects. Adrenaline is a safe and cheap antifibrotic drug that significantly blocks key cell cycle genes when used at high concentrations. Unless contraindicated, we recommend subconjunctival injections of adrenaline (0.05%) in all glaucoma bleb-forming surgeries.

Carboxymethyl chitosan regulates macrophages polarization to inhibit early subconjunctival inflammation in conjunctival injury

Persistent subconjunctival inflammation leads to subconjunctival fibrosis and eventual visual impairment. There is an unmet need for how to effectively inhibit subconjunctival inflammation. Herein, the effect of carboxymethyl chitosan (CMCS) on subconjunctival inflammation was investigated and the mechanism was involved. The evaluation of cytocompatibility demonstrated that CMCS had good biocompatibility. The in vitro results showed that CMCS inhibited secretions of pro-inflammatory cytokines (IL-6, TNF-α, IL-8 and IFN-γ) and chemokines (MCP-1), and downregulated TLR4/MyD88/NF-κB pathway in M1. The in vivo results displayed that CMCS alleviated conjunctival edema and congestion, and improved conjunctival epithelial reconstruction significantly. Both in vitro and in vivo results demonstrated that CMCS inhibited the infiltration of macrophages and reduced the expressions of iNOS, IL-6, IL-8 and TNF-α in the conjunctiva. Given that CMCS indicated the activities of inhibiting M1 polarization, NF-κB pathway, and subconjunctival inflammation, which may be employed as a potent treatment for subconjunctival inflammation.

The influence of trace elements on the therapeutic success of suprachoroidal draining devices

PURPOSE

The therapeutic success of minimal invasive glaucoma surgery (MIGS) is challenging due to many factors including fibrotic or occlusive events. Recent clinical data show sudden peaks of intraocular pressure (IOP) in the postoperative care of glaucoma patients after suprachoroidal draining stents. Yet, the reasons for the IOP peaks are speculative. As a link between trace elements and fibrosis had been previously observed in systemic disorders, the present study aimed to investigate the impact of trace elements on the therapeutic success of the suprachoroidal draining stents in patients with open-angle glaucoma (OAG).

MATERIAL AND METHODS

An analysis of a prospective single-center study was done: fifty-five eyes of patients with OAG (29 female, 26 male) underwent Cypass Micro-Stent implantation either as a stand-alone procedure or combined with cataract surgery. All patients underwent pre-operatively an ophthalmological examination which included slit lamp biomicroscopy and fundoscopy. IOP was measured by Goldmann applanation tonometry. Functional and morphometric data were assessed by Octopus G1-perimetry, which included measurement of retinal nerve fiber layer thickness (Spectralis OCT). Data of the patients' follow-ups were recorded during 18 months post-operatively. The therapeutic success of CyPass Micro-Stent was classified as 'success' (IOP reduction ≥20% compared to a pre-operative baseline without any medication), 'qualified success' (IOP reduction ≥20 % with same or lower additional eye medication), and 'failure' (IOP reduction ≤20 % or additional surgical treatment necessary). Aqueous humour was extracted once during surgery for analysis of the level of 14 trace elements: Copper (Cu), Cadmium (Cd), Cobalt (Co), Chromium (Cr), Iron (Fe), Lithium (Li), Magnesium (Mg), Manganese (Mn), Phosphorus (P), Lead (Pb), Titanium (Ti), Uranium (U), Vanadium (V), and Zinc (Zn). Analysis of the trace elements was done using an ELEMENT 2, ICP-sf-MS instrument (Thermo-Fisher Scientific, Bremen, Germany). Analysis of levels of trace elements was done across the patients' groups of the three subclasses of therapeutic success. Statistical investigations for substantial differences were conducted using the method of least squares to fit general linear models and mixed models. The last one for the repeated measurements of IOP.

RESULTS

Levels of Mg were significantly lower one month postoperatively in the success group (LS-Mean 1.30 mg/L) compared to the qualified success group (LS-Mean 1.22 mg/L; p-value = 0.04). Fe was significantly increased in the failure group (LS-Mean 2.07 µg/L) compared to the qualified success group (LS-Mean 1.64 µg/L; p-value = 0.019) after 3 months of follow-up. Additionally, Fe levels were significantly lower in the success group (LS-Mean 1.47 µg/L) compared to the failure cohort (LS-Mean 2.07 µg/L; p-value = 0.009). After a period of 18 months, significantly higher levels of Mn were observed in the success group (LS-Mean 1.24 µg/L) than in the failure group (LS Mean 0.30 µg/L, p-value = 0.019).

CONCLUSION

The present data might suggest that trace elements can influence therapeutic success of suprachoroidal draining devices postoperatively and thus offer first hints for potential novel therapeutic options.

Nanofiber-based glaucoma drainage implant improves surgical outcomes by modulating fibroblast behavior

Biomaterials are implanted in millions of individuals worldwide each year. Both naturally derived and synthetic biomaterials induce a foreign body reaction that often culminates in fibrotic encapsulation and reduced functional lifespan. In ophthalmology, glaucoma drainage implants (GDIs) are implanted in the eye to reduce intraocular pressure (IOP) in order to prevent glaucoma progression and vision loss. Despite recent efforts towards miniaturization and surface chemistry modification, clinically available GDIs are susceptible to high rates of fibrosis and surgical failure. Here, we describe the development of synthetic, nanofiber-based GDIs with partially degradable inner cores. We evaluated GDIs with nanofiber or smooth surfaces to investigate the effect of surface topography on implant performance. We observed in vitro that nanofiber surfaces supported fibroblast integration and quiescence, even in the presence of pro-fibrotic signals, compared to smooth surfaces. In rabbit eyes, GDIs with a nanofiber architecture were biocompatible, prevented hypotony, and provided a volumetric aqueous outflow comparable to commercially available GDIs, though with significantly reduced fibrotic encapsulation and expression of key fibrotic markers in the surrounding tissue. We propose that the physical cues provided by the surface of the nanofiber-based GDIs mimic healthy extracellular matrix structure, mitigating fibroblast activation and potentially extending functional GDI lifespan.

Topical Losartan: Practical Guidance for Clinical Trials in the Prevention and Treatment of Corneal Scarring Fibrosis and Other Eye Diseases and Disorders

Losartan is an angiotensin II receptor blocker (ARB) that impedes transforming growth factor (TGF) beta signaling by inhibiting activation of signal transduction molecule extracellular signal-regulated kinase (ERK). Studies supported the efficacy of topical losartan in decreasing scarring fibrosis after rabbit Descemetorhexis, alkali burn, and photorefractive keratectomy injuries, and in case reports of humans with scarring fibrosis after surgical complications. Clinical studies are needed to explore the efficacy and safety of topical losartan in the prevention and treatment of corneal scarring fibrosis, and other eye diseases and disorders where TGF beta has a role in pathophysiology. These include scarring fibrosis associated with corneal trauma, chemical burns, infections, surgical complications, and persistent epithelial defects, as well as conjunctival fibrotic diseases, such as ocular cicatricial pemphigoid and Stevens-Johnson syndrome. Research is also needed to explore the efficacy and safety of topical losartan for hypothesized treatment of transforming growth factor beta-induced (TGFBI)-related corneal dystrophies (Reis-Bu¨cklers corneal dystrophy, lattice corneal dystrophy type 1, and granular corneal dystrophies type 1 and type 2) where deposited mutant protein expression is modulated by TGF beta. Investigations could also explore the efficacy and safety of topical losartan treatments to reduce conjunctival bleb scarring and shunt encapsulation following glaucoma surgical procedures. Losartan and sustained release drug delivery devices could be efficacious in treating intraocular fibrotic diseases. Dosing suggestions and precautions that should be considered in trials of losartan are detailed. Losartan, as an adjuvant to current treatments, has the potential to augment pharmacological therapeutics for many ocular diseases and disorders where TGF beta plays a central role in pathophysiology.

Scar formation in the presence of mitomycin C and the anti-fibrotic antibody in a rabbit model of glaucoma microsurgery: A pilot study

Purpose

This study aimed to evaluate the utility of a rationally engineered antibody that directly blocks collagen fibrillogenesis to reduce scar tissue formation associated with subconjunctival glaucoma surgery.

Material and methods

Fourteen eyes of 7 adult rabbits underwent glaucoma filtering surgery using XEN 45 Gel Stent. The rabbits' eyes were divided randomly into three treatment groups: (i) treated with the antibody, (ii) treated with mitomycin C, and (iii) treated with the antibody and mitomycin C. Following surgeries, the intraocular pressure and bleb appearance were evaluated in vivo. The rabbits were sacrificed 8 weeks after the surgery, and their eyes were harvested and processed for tissue analysis. Subsequently, tissue samples were analyzed microscopically for fibrotic tissue and cellular markers of inflammation. Moreover, the collagen-rich fibrotic tissue formed around the stents was analyzed using quantitative histology and infrared spectroscopy. The outcomes of this study were analyzed using the ANOVA test.

Results

This study demonstrated no significant differences in intraocular pressure, bleb appearance, or presence of complications such as bleb leak among the treatment groups. In contrast, we observed significant differences among the subpopulations of collagen fibrils formed within scar neo-tissue. Based on the spectroscopic analyses, we determined that the relative content of mature collagen cross-links in the antibody-treated group was significantly reduced compared to other groups.

Conclusions

Direct blocking of collagen fibrillogenesis with the anti-collagen antibody offers potentially beneficial effects that may reduce the negative impact of the subconjunctival scarring associated with glaucoma filtering surgery.

Iris abnormalities may influence the efficacy and filtration strategies of Posner-Schlossman syndrome: a retrospective study involving trabeculectomy, ExPRESS and Ahmed valve implants

PURPOSE

To evaluate and compare the one-year efficacy and influencing factors of different filtration surgeries on Posner-Schlossman syndrome (PSS) patients.

METHODS

A retrospective study enrolling 91 PSS patients who underwent filtering surgeries and were followed for at least one year. Unilateral PSS was diagnosed as recurrent attacks of mild, unilateral, non-granulomatous anterior uveitis, elevated intraocular pressure (IOP), keratic precipitates (KPs) on the corneal endothelium, open angle, no posterior synechia, and no inflammatory lesions in the posterior segment; the IOP and anterior segment returned to normal between attacks. Medical histories and thorough ocular examination results were collected. Trabeculectomy and ExPRESS were chosen as the first line and AGV was considered for those under high risk of fibrosis. Follow-up data, mainly IOP, best-corrected visual acuity (BCVA), and anterior segment manifestations at the 1st week, 6th month, and 12th month were generated and analyzed. Iris abnormalities were determined by depigmentation or atrophic changes on the anterior segment photograph. Complete surgical success was defined as 5 mmHg < IOP ≤ 21 mmHg without IOP-lowering drug or needle revision; qualified surgical success was defined as 5 mmHg < IOP ≤ 21 mmHg with IOP-lowering drugs or needle revisions. Survival analysis was performed to obtain the success rates.

RESULTS

At the 12th month, the complete surgical success rate of trabeculectomy (N = 54), ExPRESS (N = 23), and AGV group (N = 14) was 58.97% (95%CI 46.91-77.09%), 84.21% (95%CI 68.33-100.87%), and 100%; the qualified success rate was 71.79% (95%CI 62.46-88.34%), 89.47% (95%CI 77.07-103.33%), and 100%, respectively. Patients undergoing trabeculectomy experienced the largest decline of BCVA (from 0.58±0.46 to 1.01±0.51, P < .05); the trabeculectomy group endured the highest IOP (20.84±9.92 mmHg) compared to ExPRESS (14.51±2.86 mmHg, P < .05) and AGV group (13.17±3.32 mmHg, P < .05). At the 12th month, in the ExPRESS group, patients with iris abnormalities had higher IOP than the normal ones (15.65±2.05 mmHg, 12.93±3.17 mmHg, P < .05). ExPRESS helped patients with iris abnormalities maintain lower IOP than trabeculectomy (15.65±2.05 mmHg, 22.52±10.67 mmHg, P < .05). Three patients developed hypotony at the 3rd month (1 in ExPRESS and 2 in trabeculectomy group).

CONCLUSION

AGV and ExPRESS performed better than trabeculectomy in PSS patients in terms of IOP and success rate. Iris abnormalities might influence the postoperative IOP and this may be valuable in guiding filtration strategies.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (No. ChiCTR1800017532, date: 2018/08/02).

ALK5 Inhibition of Subconjunctival Scarring From Glaucoma Surgery: Effects of SB-431542 Compared to Mitomycin C in Human Tenon's Capsule Fibroblasts

Purpose

The gold standard for managing postoperative ocular fibrosis in glaucoma surgery is the chemotherapeutic mitomycin C (MMC) despite its association with significant adverse effects. This study compares in vitro the antifibrotic efficacy and cytotoxicity of the small-molecule TGFβ1 inhibitor SB-431542 (SB) to MMC.

Methods

To measure collagen contraction, human Tenon's capsule fibroblasts (HTCFs) embedded in a three-dimensional collagen lattice were exposed to 0.2 mg/mL MMC or 20 µM SB followed by incubation with 2 ng/mL TGFβ1. Total protein extracted from experimentally treated HTCFs underwent immunoblotting for α-smooth muscle actin (α-SMA), matrix metallopeptidase 9 (MMP-9), and EDA splice-variant fibronectin (EDA-FN) expression. Cytotoxicity and cell metabolism were assessed using LIVE/DEAD staining, lactate dehydrogenase (LDH) assay, and methylthiazole tetrazolium (MTT) assay.

Results

Collagen lattice contraction in TGFβ1-induced HTCFs was significantly lowered by SB and MMC. Pretreatment with SB and MMC significantly lowered protein expression of α-SMA, MMP-9, and EDA-FN in HTCFs relative to TGFβ1 alone. HTCF viability in collagen lattices was significantly reduced with MMC pretreatment but not SB pretreatment. MMC-pretreated HTCFs had a significant increase in LDH release after 3 hours and a decrease in MTT activity after 20 minutes, while SB-pretreated HTCFs showed no significant changes via MTT or LDH assay during the same treatment period.

Conclusions

SB shows comparable efficacy to MMC in reducing expression of fibrosis-promoting proteins in HTCFs and in vitro scarring activity. SB distinguishes itself from MMC by exhibiting less cytotoxicity in both two-dimensional and three-dimensional in vitro assays.

Translational Relevance

This study demonstrates in vitro the potential of SB as a safer alternative ocular antifibrotic agent.

The Antibiotic Kitasamycin-A Potential Agent for Specific Fibrosis Preventing Therapy after Fistulating Glaucoma Surgery?

One major complication after fistulating glaucoma surgeries are fibroblast-mediated scarring processes and their specific prevention is key in the development of novel pharmaceutical concepts. Within this study a possible antifibrotic potential of kitasamycin (KM) in a transforming growth factor (TGF)-β1-mediated fibroblast model was evaluated in vitro. Primary ocular fibroblasts were isolated, cultivated and a dose-response test including determination of the half maximal effective concentration (EC50) for KM was conducted. Transformation of fibroblasts into myofibroblasts was induced by TGF-β1and immunofluorescence (IF), and Western blot (WB) analyses were performed with fibroblasts and myofibroblasts. IF analyses were carried out using antibodies against α-smooth muscle actin (α-SMA) and fibronectin, and protein detection of intracellular and extracellular proteins was performed by WB. Using the dose-response test, the viability, cytotoxicity and EC50 of KM after 24 and 48 h were determined. Fibroblasts exposed to various KM concentrations showed no increase in α-SMA and extracellular matrix expression. In TGF-ß1-stimulated myofibroblasts, KM inhibited the expression of α-SMA and fibronectin in a concentration-dependent manner. These findings demonstrate that KM could impair the transformation of fibroblasts into myofibroblasts and the expression of proteins involved in fibrotic processes, representing a potential agent for specific fibrosis prevention in future therapeutic concepts.

Understanding Inflammation-associated Ophthalmic Pathologies: A Novel 3D Co-culture Model of Monocyte-myofibroblast Immunomodulation

PURPOSE

Inflammation is associated with, and may be causal of, a variety of ophthalmic pathologies. These pathologies are currently difficult to model in vitro because they involve complex interactions between the innate immune system, stromal cells, and other cells that normally maintain ocular tissue homeostasis. Using transscleral drainage channel fibrosis after glaucoma surgery as an example of inflammation-associated ocular fibrosis, we have assessed a simple but novel 3D cell culture system designed to reveal the immunomodulatory impacts of ocular connective tissue cells on monocytes, a major cellular component of the circulating immune system.

METHODS

Primary human Tenon's capsule fibroblasts derived from five unrelated patients were activated into myofibroblasts in 3D collagen matrices under isometric tension, with and without exposure to an inflammatory cytokine-enhanced milieu, and co-cultured with an immortalized human monocyte cell line (THP-1 cells). Quantitative PCR analyses were performed on 8 candidate genes to assess the impacts of inflammatory cytokines on the myofibroblasts and the monocytes in mono-cultures and compared to cells in co-culture to clearly distinguish any co-culture-induced impacts on gene expression.

RESULTS

Our data indicate that both Tenon's capsule myofibroblasts in 3D mono-culture and THP-1 monocytes in suspension mono-culture were responsive to inflammatory cytokine stimuli. Co-culture with Tenon's capsule myofibroblasts significantly modulated the gene expression responses of THP-1 monocytes to inflammatory cytokine stimulation, indicative of an immunomodulatory "feedback" system between these cell types.

CONCLUSION

Our findings provide proof of principle for the use of simple 3D co-culture systems as a means to enhance our understanding of ocular stromal cell interactions with cells of the innate immune system and to provide more informative in vitro models of inflammation-associated ophthalmic pathologies.

Non-Viral Gene Therapy in Trabecular Meshwork Cells to Prevent Fibrosis in Minimally Invasive Glaucoma Surgery

The primary cause of failure for minimally invasive glaucoma surgery (MIGS) is fibrosis in the trabecular meshwork (TM) that regulates the outflow of aqueous humour, and no anti-fibrotic drug is available for intraocular use in MIGS. The myocardin-related transcription factor/serum response factor (MRTF/SRF) pathway is a promising anti-fibrotic target. This study aims to utilise a novel lipid nanoparticle (LNP) to deliver MRTF-B siRNA into human TM cells and to compare its effects with those observed in human conjunctival fibroblasts (FF). Two LNP formulations were prepared with and without the targeting peptide cΥ, and with an siRNA concentration of 50 nM. We examined the biophysical properties and encapsulation efficiencies of the LNPs, and evaluated the effects of MRTF-B silencing on cell viability, key fibrotic genes expression and cell contractility. Both LNP formulations efficiently silenced MRTF-B gene and were non-cytotoxic in TM and FF cells. The presence of cΥ made the LNPs smaller and more cationic, but had no significant effect on encapsulation efficiency. Both TM and FF cells also showed significantly reduced contractibility after transfection with MRTF-B siRNA LNPs. In TM cells, LNPs with cΥ achieved a greater decrease in contractility compared to LNPs without cΥ. In conclusion, we demonstrate that the novel CL4H6-LNPs are able to safely and effectively deliver MRTF-B siRNA into human TM cells. LNPs can serve as a promising non-viral gene therapy to prevent fibrosis in MIGS.

Effect of the rho-kinase inhibitor ripasudil in needling with mitomycin C for the failure of filtering bleb after trabeculectomy: a cross-sectional study

Background

Rho-kinase inhibitors can inhibit fibrosis after glaucoma surgery. This study aimed to evaluate the effect of rho-kinase inhibitor after needling procedure with mitomycin C for the failure of filtering bleb with trabeculectomy.

Methods

This retrospective single-center study examined the effects of rho-kinase inhibitor after the needling procedure. We included 27 eyes of 27 patients with glaucoma who underwent needling procedure using mitomycin C and were subsequently treated with ripasudil—a rho-associated protein kinase inhibitor (ripasudil group)—or without ripasudil (control group). The ripasudil and control groups were compared in terms of intraocular pressure (IOP) and the number of antiglaucoma medications. Success at 12 months after the needling procedure was defined as a > 20% decrease in IOP from the preoperative period without surgical reintervention.

Results

At 12 months after the needling procedure, the mean IOP decreased from 16.9 ± 4.5 to 12.6 ± 1.1 mmHg in the control group and from 16.0 ± 5.3 to 12.2 ± 1.2 mmHg in the ripasudil group (p = 0.77). The 12-month success rates were 60.00% and 56.25% in the control and ripasudil groups (p = 0.98), respectively. In the preoperative period, the numbers of antiglaucoma drugs were 0.27 ± 0.46 and 0.92 ± 0.91 in the control and ripasudil groups (p = 0.022), respectively, and at 12 months after the needling procedure, they were 1.07 ± 1.44 and 0.73 ± 1.10 (p = 0.52), respectively.

Conclusions

Treatment with ripasudil (a rho-associated protein kinase inhibitor) after the needling procedure with mitomycin C did not show better results than treatment with the mitomycin C needling procedure alone at 12 months after the procedure.

PLA-PEG Implant as a Drug Delivery System in Glaucoma Surgery: Experimental Study

Excessive postoperative scarring halts the effectiveness of glaucoma surgery and still remains a challenging problem. The purpose of this study was to develop a PLA-PEG-based drug delivery system with cyclosporine A or everolimus for wound healing modulation. Methods: PLA-PEG implants saturation with cyclosporine A or everolimus as well as their further in vitro release were analyzed. Anti-proliferative activity and cytotoxicity of the immunosuppressants were studied in vitro using human Tenon’s fibroblasts. Thirty-six rabbits underwent glaucoma filtration surgery with the application of sham implants or samples saturated with cyclosporine A or everolimus. The follow-up period was six months. A morphological study of the surgery area was also performed at seven days, one, and six months post-op. Results: PLA-PEG implants revealed a satisfactory ability to cumulate either cyclosporine A or everolimus. The most continuous period of cyclosporine A and everolimus desorption was 7 and 13 days, respectively. Immunosuppressants demonstrated marked anti-proliferative effect regarding human Tenon’s fibroblasts without signs of cytotoxicity at concentrations provided by the implants. Application of PLA-PEG implants saturated with immunosuppressants improved in vivo glaucoma surgery outcomes. Conclusions: Prolonged delivery of either cyclosporine A or everolimus by means of PLA-PEG implants represents a promising strategy of wound healing modulation in glaucoma filtration surgery.

Risk Factors for Glaucoma Drainage Device Revision or Removal Using the IRIS Registry

PURPOSE

To elucidate risk factors for revision or removal of glaucoma drainage devices (GDD) in glaucoma patients in the United States.

DESIGN

Retrospective cohort study.

METHODS

IRIS Registry (Intelligent Research in Sight) patients who underwent GDD insertion between January 1, 2013 and December 31, 2018 were included. Various demographic and clinical factors were collected. Kaplan-Meier survival plots, Cox proportional-hazard models utilizing Firth's Penalized Likelihood, and multivariate linear regression models were used. The main outcome measures were hazard ratios (HR) and beta coefficient (β) estimates.

RESULTS

A total of 44,330 distinct patients underwent at least 1 GDD implantation, and 3354 of these underwent subsequent GDD revision or removal surgery. With failure defined as GDD revision/removal, factors significantly associated with decreased failure included unknown race (HR = 0.83; P = .004) and unknown ethnicity (HR = 0.68; P < .001). Factors associated with increased risk of GDD revision/removal surgery included presence of chronic angle-closure glaucoma (HR = 1.32; P < .001) and dry eye disease (HR = 1.30; P = .007). Additionally, factors associated with a decreased average time (in days) to GDD revision/removal included male sex (β = -25.96; P = .044), unknown race (β = -55.28; P = .013), and right-eye laterality (β = -38.67; P = .026). Factors associated with an increased average time to GDD revision/removal included having a history of a past eye procedure (β = 104.83; P < .001) and being an active smoker (β = 38.15; P = .024).

CONCLUSIONS

The size and scope of the IRIS Registry allows for detection of subtle associations between risk factors and GDD revision or removal surgery. The aforementioned demographic and clinical factors may all have an impact on GDD longevity and can inform the treatment options available for glaucoma patients.

Wound Healing Response After Bleb-Forming Glaucoma Surgery With a SIBS Microshunt in Rabbits

Purpose

The PreserFlo MicroShunt is an innovative implant for the surgical treatment of glaucoma. Although usually effective, surgeries can still fail due to fibrosis. This study was conducted to gain insight into the histological aspects of the fibrotic response and find potential targets to reduce postoperative fibrosis.

Methods

Fifteen New Zealand White rabbits were implanted with a microshunt and followed up for 40 days. Animals were euthanized at postoperative days (PODs) 1, 5, and 40 to collect eyes for histological evaluation. Bleb formation and ocular health were assessed by slit-lamp (SL) biomicroscopy and optical coherence tomography (OCT). Intraocular pressure (IOP) was measured using rebound tonometry.

Results

Blebs failed after approximately 2 weeks based on bleb survival and IOP measurements. No severe complications were observed with OCT and SL. Histology revealed a wide variety of cells, in the bleb and around the microshunt, including polymorphonuclear leucocytes (PMNs), myofibroblasts, and foreign body giant cells, at different PODs.

Conclusions

Implantation of a poly(styrene-b-isobutylene-b-styrene) microshunt in rabbits resulted in the occurrence of a wide variety of cells during the wound-healing response. Future research should further elucidate the potential of these (earlier often overlooked) cells to target the fibrotic response in vivo—for example, by developing novel antifibrotic drugs, methods for sustained delivery of medications, or augmenting material properties.

Translational Relevance

Current antifibrotic therapies aim to inhibit myofibroblasts; however, a wide variety of cells are involved in the fibrotic response. Future research focusing on these cells could offer novel methods for reducing the fibrotic response after glaucoma surgery.

Anti-glaucoma medications lowered decorin and altered profibrotic proteins in human tenon's fibroblasts

Long term exposure to anti-glaucoma medications (AGMs) leads to an increase in extracellular matrix (ECM) accumulation in primary glaucoma patients. This study aims to evaluate the effect of topical AGMs in primary human tenon's fibroblasts (HTFs) and analyze the expression of profibrotic and anti-fibrotic proteins. Primary HTFs were cultured from patients undergoing cataract (control) and trabeculectomy. The different types of AGMs in single/multiple combinations (BB, PG, AA, CAI, CH, combinations of 3- PG + AA + CAI, 4A- BB + PG + AA + CAI, 4B- BB + PG + CAI + CH and 5- BB + PG + AA + CAI + CH) on chronic exposure were tested for cell viability using MTT assay and morphological alterations. Profibrotic proteins mainly SPARC, LOXL2, COL1A1 and anti-fibrotic DCN were analyzed in treated HTFs using q-PCR and ELISA. Sirius red staining and collagen gel contraction (CGC) assay were performed to assess collagen synthesis and the contractility of HTFs, respectively. Except for AA and CH, the other AGMs at a higher concentration were found to decrease the cell viability of HTFs. The morphology of HTFs were altered on exposure to BB, CH and AA; Profibrotic proteins i.e., SPARC, LOXL2 and COL1A1 were significantly increased (p < 0.05) on exposure to a combination of AGMs with TGF-β1, whereas the anti-fibrotic DCN expression was significantly lowered (p < 0.05) in single/multiple AGM exposure. Sirius red staining showed increased collagen synthesis with combinations of AGMs with TGF-β1. Meanwhile, HTFs showed increased collagen gel contraction with TGF-β1, CAI and CH. This study reveals that altered profibrotic proteins, with significantly lowered DCN on chronic exposure of AGMs in HTFs.

Rational Design of Microfluidic Glaucoma Stent

Glaucoma is a common, irreparable eye disease associated with high intraocular pressure. One treatment option is implantation of a stent to lower the intraocular pressure. A systematic approach to develop a microchannel stent meshwork that drains aqueous humor from the anterior chamber of the eye into the subconjunctival space is presented. The stent has a large number of outlets within its mesh structure that open into the subconjunctiva. The development approach includes a flow resistance model of the stent. Local adaption of the stent’s tubular dimensions allows for adjustment of the flow resistance. In this way, an evenly distributed outflow into the subconjunctiva is achieved. We anticipate that microblebs will form at the stent outlets. Their size is crucial for drainage and control of intraocular pressure. An analytical model for bleb drainage is developed based on the porous properties of the subconjunctival tissue. Both models—the stent flow resistance model and the bleb drainage model—are verified by numerical simulation. The models and numerical simulation are used to predict intraocular pressure after surgery. They allow for a systematic and personalized design of microchannel stents. Stents designed in this way can stabilize the intraocular pressure between an upper and lower limit.

Surgical Advancement of Tenon's Layer During Trabeculectomy Improves Bleb Morphology

Trabeculectomy surgery remains the gold standard incisional glaucoma surgical procedure in many practices, particularly for patients requiring intraocular pressure (IOP) in the low teens or below. However, trabeculectomy surgery is associated with complications including leakage, over filtration, or fibrosis of the surgical bleb. Morphology of the surgical bleb is an important predictor of surgical success defined as long-term IOP reduction with minimal to no complications. There have been many, often subtle, variations in the surgical technique in hopes of improving long-term IOP reduction. However, fewer changes have been implemented specifically to modify bleb morphology. In our surgical practice, we began performing a thorough dissection and advancement of Tenon's layer with incorporation into the conjunctival closure in a 2-layered manner. This technique allowed flow of aqueous to a delineated potential space between sclera and Tenon's layer. Our clinical observations were improved bleb morphology characterized by diffuse, low-lying blebs with nonischemic overlying conjunctiva compared with those performed with a more traditional trabeculectomy technique. Since we incorporated this change into our practice at a defined time, we have a small number of patients in our practice that had a more traditional trabeculectomy technique in the fellow eye. Therefore, in our surgical practice, a small number of patients had trabeculectomy in 1 eye before implementation of this new technique, and then had trabeculectomy in the fellow eye after this technique was adopted, providing opportunity for comparison of bleb morphology with and without Tenon advancement. In series we present two representative, index cases and describe our surgical technique.

Elucidating the Therapeutic Potential of Cell-Penetrating Peptides in Human Tenon Fibroblast Cells

Cell-penetrating peptides (CPPs) have been widely used as vehicles for delivering therapeutic molecules to the site of action. Apart from their delivering potential, the biological effects of CPPs have not been explored in detail. JTS-1 is a CPP that has been reported to have gene delivery functions, although its biological role is yet to be determined. Hence, in this study, we revealed the biological mechanism such as its uptake mechanism and immunogenic potential and function using primary human tenon fibroblast (TF) cells collected from patients undergoing glaucoma trabeculectomy surgery. Our results showed that the JTS-1 peptide has an α-helical structure and is nontoxic up to 1 μM concentration. It was found to be colocalized with early endosome (Rab5), recycling endosome (Rab7), and Rab11 and interacted with major histocompatibility complex (MHC) class I and II. The peptide also affected actin polymerization, which is regulated by cofilin phosphorylation and ROCK1 localization. It also inhibited TF cell proliferation. Therefore, the JTS-1 peptide could be used as a possible therapeutic agent for modifying the fibrosis process, where TF proliferation is a key cause of surgery failure.

Emerging Evidence of Noncoding RNAs in Bleb Scarring after Glaucoma Filtration Surgery

PURPOSE

To conduct a narrative review of research articles on the potential anti- and pro-fibrotic mechanisms of noncoding RNAs following glaucoma filtration surgery.

METHODS

Keyword searches of PubMed, and Medline databases were conducted for articles discussing post-glaucoma filtration surgeries and noncoding RNA. Additional manual searches of reference lists of primary articles were performed.

RESULTS

Fifteen primary research articles were identified. Four of the included papers used microarrays and qRT-PCR to identify up- or down-regulated microRNA (miRNA, miR) profiles and direct further study, with the remainder focusing on miRNAs or long noncoding RNAs (lncRNAs) based on previous work in other organs or disease processes. The results of the reviewed papers identified miR-26a, -29b, -139, -155, and -200a as having anti-fibrotic effects. In contrast, miRs-200b and -216b may play pro-fibrotic roles in filtration surgery fibrosis. lncRNAs including H19, NR003923, and 00028 have demonstrated pro-fibrotic effects.

CONCLUSIONS

Noncoding RNAs including miRNAs and lncRNAs are emerging and promising therapeutic targets in the prevention of post-glaucoma filtration surgery fibrosis.

Comparison of long-term outcomes of trabeculectomy and risk factors for failure in eyes post penetrating keratoplasty or Descemet's stripping endothelial keratoplasty

Purpose:

To evaluate the outcomes of trabeculectomy, graft survival, and risk factors for failure in post penetrating keratoplasty (PK) and Descemet’s stripping endothelial keratoplasty (DSEK) eyes.

Methods:

We reviewed charts of eyes that underwent trabeculectomy for post keratoplasty glaucoma PK [25 eyes] and DSEK [14 eyes] between 1993 and 2019. The demographics, clinical features, and surgical outcomes were evaluated. Success of trabeculectomy was defined as complete when the intraocular pressure (IOP) was >5 and ≤21 mmHg without antiglaucoma medications (AGM) and qualified with AGM. Clear and compact graft was considered for graft success.

Results:

Median (interquartile range [IQR] preoperative IOP in post-PK eyes and post-DSEK eyes was comparable, 32 (28–38) vs. 31.5 (25–36) mmHg, P = 0.38). Median number of preoperative AGMs was comparable (P = 0.78). Median postoperative follow-up was longer in post-PK, compared with post-DSEK, 2.5 (1.3–3.3) vs. 1 (0.3–2.9) years (P = 0.05). Kaplan–Meier survival estimates for complete and qualified success of trabeculectomy at 3 years were 23.7% and 73.3%, respectively, for PK and 45.8% and 71.6%, respectively, for DSEK. Kaplan–Meier survival estimates for graft survival were 91.8% up to 3 years for PK and 100% until 2 years and 77.8% at 3 years for DSEK. Higher IOP prior to trabeculectomy was a risk factor for failure of trabeculectomy (P = 0.03) and older age was a risk factor for graft failure (P = 0.05) in PK eyes. Number of prior corneal surgeries (P = 0.05) was associated with failure of trabeculectomy and graft failure in post-DSEK eyes.

Conclusion:

Trabeculectomy had moderate qualified success in post-PK and DSEK eyes at 3 years. Higher pretrabeculectomy IOP and higher number of prior corneal surgeries were significantly associated with failure of trabeculectomy in PK and DSEK eyes, respectively.

Promotion of conjunctival fibroblast-mediated collagen gel contraction by mast cells through up-regulation of matrix metalloproteinase release and activation

Mast cells and conjunctival fibroblasts contribute to conjunctival wound healing and allergic ocular inflammation. The number of mast cells in the conjunctiva is increased in individuals with cicatricial fibrosis-causing ocular surface diseases and after glaucoma filtering surgery, suggesting that these cells may contribute to the scarring observed after such surgery. We studied the potential mechanism of fibroblast-mast cell interaction in the healing of conjunctival wounds using a three-dimensional collagen gel culture system. We found that mast cells derived from the bone marrow of mice embedded in a collagen gel did not induce gel contraction. However, an increase in mast cells was associated with increased collagen gel contraction mediated by mouse conjunctival fibroblasts. The extent of collagen degradation was not affected by the co-culture of mast cells and conjunctival fibroblasts. Gelatin zymography disclosed that mast cells increased the amounts of both the pro form of matrix metalloproteinase (MMP)-9 and the active form of MMP-2 in supernatants of conjunctival fibroblast cultures. Furthermore, the potentiating effect of mast cells on contraction of the collagen gel through conjunctival fibroblasts was attenuated by the addition of a synthetic MMP inhibitor. Thus, current results suggest that mast cells accelerate the conjunctival fibroblast-dependent contraction of collagen gel by increasing the release as well as activation of MMPs. Therefore, the interaction between mast cells and conjunctival fibroblasts may contribute to conjunctival scar formation after glaucoma filtering surgery.

Safety, efficacy, and timing of Nd:YAG laser goniopuncture after nonpenetrating deep sclerectomy for glaucoma: A retrospective cohort study

BACKGROUND

Neodymium-doped yttrium aluminum garnet laser goniopuncture is an adjuvant procedure for nonpenetrating deep sclerectomy. We investigated optimal laser goniopuncture timing and the effect of laser iridoplasty on success rates.

METHODS

This single-center retrospective cohort study compared intraocular pressure control in patients with early versus late laser goniopuncture after nonpenetrating deep sclerectomy and evaluated the effects of laser iridoplasty pretreatment. A 3-month cut-off was used to define early versus late laser goniopuncture. The primary outcome was the proportion of patients maintaining intraocular pressure control according to definitions of complete (no medications) and qualified (with medications) success at 15, 18, and 21 mmHg thresholds. Data were analyzed using right-censored Kaplan-Meier estimation and log-rank testing.

RESULTS

A total of 124 eyes of 124 patients were analyzed. Complete success rates after 3 years were 9.2%, 14.6%, and 23.3% for early laser goniopuncture and 21.8%, 26.0%, and 55.4% for late laser goniopuncture for 15, 18, and 21 mmHg, respectively (all p < .01). Qualified success rates after 3 years were 16.6%, 24.8%, and 40.9% for early laser goniopuncture and 21.5%, 56.1%, and 69.6% for late laser goniopuncture for 15, 18, and 21 mmHg, respectively (p  =  .096, .0026, .0061). Late laser goniopuncture was associated with decreased risk of iris incarceration and bleb collapse. Iridoplasty pretreatment was not associated with improved outcomes.

CONCLUSION

Late laser goniopuncture (3-month cut-off) was associated with better intraocular pressure control and less adverse events than early laser goniopuncture.

8-year follow-up of Excimer Laser Trabeculostomy Alone and Combined With Phacoemulsification in Patients with Open Angle Glaucoma

PURPOSE

To describe the 8-year results of excimer laser trabeculostomy (ELT) alone and ELT in conjunction with phacoemulsification (phaco).

SETTING

University Hospital.

DESIGN

Retrospective review.

METHODS

308 nm excimer laser energy delivered via an intraocular fiberoptic probe created channels through the inner wall of Schlemm's canal. Two groups were studied: ELT Alone and ELT + Phaco. Patients were adults with open-angle glaucoma or ocular hypertension on one or more intraocular pressure (IOP) lowering medications and, in the Phaco + ELT group, visually significant cataract. Primary outcome measures: Change of IOP from baseline and number of IOP lowering medications.

RESULTS

164 eyes in two groups, ELT Alone (n=90) and ELT + Phaco (n=74) were followed for 8 years. Baseline IOP in the ELT Alone group was 22.17 ± 7.0 mmHg and in the ELT+ Phaco group 21.9±6.44 mmHg. IOP in ELT Alone decreased to 16.84±5.2 mmHg at 1 year (n=69) and remained at 15.9±3.5 (n=19) at 8 years. IOP in ELT+ Phaco was 14.04±4.1 mmHg at 1 year (n=63) and 13.7±2.8 mmHg at 8 years (n=13). IOP lowering medications at baseline in ELT alone were 1.85±0.8 and decreased to 1.19±1.10 at 1 year and 1.4±1.4 at 8 years. In ELT + Phaco at baseline 1.58±0.8 and decreased to 0.97 ± 0.95 at 1 year and 1.85±0.7 at 8 years.

CONCLUSIONS

ELT demonstrates long-term IOP lowering and decrease in IOP lowering medications. Benefits of this laser based implant-free MIGS procedure include a high safety profile and long-term efficacy.

Novel Bacterial Cellulose Membrane to Reduce Fibrosis Following Trabeculectomy

PURPOSE

The aim was to evaluate the effectiveness of bacterial cellulose membrane (BCM) in preventing fibrosis in trabeculectomy and the biocompatibility of BCM with conjunctiva and sclera.

MATERIALS AND METHODS

Twenty-one eyes of 21 adult rabbits underwent fornix-based trabeculectomy. Standard surgery was done to control group (CG, n=7). Mitomycin-C (MMC) (0.3 mg/mL, 3 min) was applied to MMC group only (MMCG, n=7). BCM (~100 µm thick, 10×10 mm, single layer) was covered on the sclerotomy area before conjunctiva was closed in BCM group (BCMG, n=7). Intraocular pressures (IOP) were measured before, and 7, 14, 28, and 45 days after surgery (IOP-POD7, POD14, POD28, POD45). The IOP decrease were expressed as DIOP%-POD7, DIOP%-POD14, DIOP%-POD28, and DIOP%-POD45. The rabbits were sacrificed on the 45th day. Conjunctival vessel number, degrees of fibrosis, total inflammation, foreign body reaction, inflammatory cell types (B cells, T cells, plasma cells), macrophages, bleb spaces and the expression of α-smooth muscle actin were studied using histopathology and immunohistochemistry techniques. The groups were compared using nonparametric tests.

RESULTS

There was no statistically significant difference between the groups regarding baseline IOP and DIOP%-POD7 (P>0.05). While DIOP%-POD14, 28 and 45 were similar between BCMG and MMCG, they were significantly lower in CG (P<0.05). The lowest conjunctival vessel number was detected in the MMCG but the difference was not significant. There was no difference between BCMG and CG with regard to the numbers of B cells, T cells, and macrophages, however, these cells were significantly lower in MMCG (P<0.05). Five cases had mild and 2 cases had moderate foreign body reaction in the BCMG. There was mild to moderate inflammation in all BCM cases. While fibrosis and α-smooth muscle actin staining were higher in the CG (P<0.001), they were minimal in the BCM and MMCGs.

CONCLUSIONS

BCM showed good biocompatibility and provided better control of IOP with minimal fibrosis at the trabeculectomy site compared with the control group.

AGTR1 blocker attenuates activation of Tenon's capsule fibroblasts after glaucoma filtration surgery via the NF-κB signaling pathway

Activation of Tenon's capsule fibroblasts limits the success rate of glaucoma filtration surgery (GFS), the most efficacious therapy for patients with glaucoma. Angiotensin type 1 receptor (AGTR1) is involved in tissues remodeling and fibrogenesis. However, whether AGTR1 is involved in the progress of fibrogenesis after GFS is not fully elucidated. The aim of this study was to investigate the role of an AGTR1 in scar formation after GFS and the potential anti-fibrosis effect of AGTR1 blocker. AGTR1 expression level was increased in subconjunctival tissues in a rat model of GFS and transforming growth factor-beta 2 (TGF-β2)-induced human Tenon's capsule fibroblasts (HTFs). AGTR1 blocker treatment suppressed TGF-β2-induced HTF migration and α-smooth muscle actin (α-SMA) and fibronectin (FN) expression. AGTR1 blocker treatment also attenuated collagen deposition and α-SMA and FN expression in subconjunctival tissues of the rat model after GFS. Moreover, AGTR1 blocker decreased TGF-β2-induced P65 phosphorylation, P65 nuclear translocation, and nuclear factor kappa B (NF-κB) luciferase activity. Additionally, BAY 11-7082 (an NF-κB inhibitor) significantly suppressed HTF fibrosis. In conclusion, our results indicate that AGTR1 is involved in scar formation after GFS. The AGTR1 blocker attenuates subconjunctival fibrosis after GFS by inhibiting the NF-κB signaling pathway. These findings indicate that targeting AGTR1 is a potential approach to attenuate fibrosis after GFS.

Immune responses to injury and their links to eye disease

The eye is regarded as an immune privileged site. Since the presence of a vasculature would impair vision, the vasculature of the eye is located outside of the central light path. As a result, many regions of the eye evolved mechanisms to deliver immune cells to sites of dysgenesis, injury, or in response to the many age-related pathologies. While the purpose of these immune responses is reparative or protective, cytokines released by immune cells compromise visual acuity by inducing inflammation and fibrosis. The response to traumatic or pathological injury is distinct in different regions of the eye. Age-related diseases impact both the anterior and posterior segment and lead to reduced quality of life and blindness. Here we focus attention on the role that inflammation and fibrosis play in the progression of age-related pathologies of the cornea and the lens as well as in glaucoma, the formation of epiretinal membranes, and in proliferative vitreoretinopathy.

Forkhead domain inhibitory-6 attenuates subconjunctival fibrosis in rabbit model with trabeculectomy

Antiproliferative therapies are crucially important for improving the success rate of the glaucoma filtration surgeries. In this study, we investigated the potential efficacy of Forkhead Domain Inhibitory-6 (FDI-6) in inhibiting post-trabeculectomy subconjunctival fibrosis. In vitro, the effect of FDI-6 (10 μM) on fibrotic response and its underlying mechanism were investigated in rabbit tenon's fibroblasts (RTFs) treated with or without transforming growth factor-β1 (TGF-β1, 20 ng/mL). In vivo, FDI-6 (40 μM) was injected subconjunctivally to a rabbit trabeculectomy model. Intraocular pressure (IOP) changes were monitored within the 14-day period post-surgery. Bleb morphology and subepithelial fibrosis at the operating area were evaluated with slit lamp and confocal microscopic examinations and with histologic examinations. The results showed that, in cell culture studies, FDI-6 suppressed the proliferation, migration, collagen gel contraction and the expression levels of fibronectin (FN) and α-smooth muscle actin (α-SMA) in RTFs with TGF-β treatment by down-regulating the TGF-β1/Smad2/3 signaling pathway. In animal studies, the IOPs of the FDI-6-treated group were significantly lower than those of the saline-treated group after trabeculectomy. The FDI-6-treated eyes showed a better bleb appearance with fewer blood vessels compared to the saline-treated eyes. The analysis of confocal microscopy in vivo and histopathology revealed that subconjunctival fibrosis after trabeculectomy was significantly attenuated in the FDI-6-treated group compared to the controls. In conclusion, our studies indicate that FDI-6 exerts an inhibitory effect on subconjunctival fibrosis caused by trabeculectomy, holding potentials as a new antiproliferative agent used in anti-glaucoma filtration surgeries in the future.

The Effect of a Triple Combination of Bevacizumab, Sodium Hyaluronate and a Collagen Matrix Implant in a Trabeculectomy Animal Model

Currently available anti-scarring treatments for glaucoma filtration surgery (GFS) have potentially blinding complications, so there is a need for alternative and safer agents. The effects of the intrableb administration of a new combination of the anti-VEGF bevacizumab, sodium hyaluronate and a collagen matrix implant were investigated in a rabbit model of GFS, with the purpose of modulating inflammation, angiogenesis, fibroblast migration and fibrogenesis in the wound healing process. A comparative-effectiveness study was performed with twenty-four rabbits, randomly assigned to the following treatments: (a) biodegradable collagen matrix implant (Olo), (b) bevacizumab-loaded collagen matrix implant (Olo-BVZ), (c) bevacizumab-loaded collagen matrix implant combined with sodium hyaluronate (Olo-BVZ-H5) and (d) sham-operated animals (control). Rabbits underwent a conventional trabeculectomy and were studied over 30 days in terms of intraocular pressure and bleb characterization (height, area and vascularity in central, peripheral and non-bleb zones). Histologic differences among groups were further evaluated at day 30 (inflammation, total cellularity and degree of fibrosis in the area of surgery). Local delivery of bevacizumab (Olo-BVZ and Olo-BVZ-H5) increased the survival of the filtering bleb by 21% and 31%, respectively, and generated a significant decrease in inflammation and cell infiltration histologically 30 days after surgery, without exhibiting any local toxic effects. Olo-BVZ-H5 showed less lymphocyte infiltration and inflammation than the rest of the treatments. Intraoperative intrableb implantation of bevacizumab, sodium hyaluronate and a collagen matrix may provide an improved trabeculectomy outcome in this model of intense wound healing. This study showed an effective procedure with few surgical complications and a novel combination of active compounds that offer new possibilities to improve the efficacy of filtration surgery.

Combined and stand-alone XEN 45 gel stent implantation: 3-year outcomes and success predictors

PURPOSE

To evaluate the 3-year treatment outcomes of XEN 45 gel stent in open-angle glaucoma patients.

METHODS

In this prospective, single-centre interventional study, consecutive eyes with uncontrolled intraocular pressure (IOP) or signs of disease progression despite medical treatment underwent XEN implantation either alone or combined with phacoemulsification (Phaco + XEN).

MAIN OUTCOME MEASURES

Surgical success was defined as 'complete' when 36-month unmedicated IOP was ≤15 mmHg with a relative IOP reduction ≥ 20% from medicated baseline, while the definition of qualified success allowed no more medications than at baseline. Other definitions of success with different IOP thresholds were also analysed. Secondary outcomes included mean IOP reduction, changes in ocular hypotensive medications and rates of reoperations.

RESULTS

Out of 149 eyes initially included, 92 eyes (61.7%) of 68 patients had complete 3-year data (XEN: n = 26; Phaco + XEN: n = 66) after 38.2% were lost to follow-up. Mean age was 76.3 ± 9.1 years, and 66.2% were female. Mean medicated IOP decreased from 20.8 ± 7.4 mmHg (21.0 ± 7.4 [XEN] vs. 20.0 ± 6.9 mmHg [Phaco + XEN]) at baseline to 13.1 ± 3.4 mmHg (12.9 ± 2.9 [XEN] vs. 12.9 ± 3.4 [Phaco + XEN]) at 3 years (-37.0%; p < 0.001). Medications decreased from 1.9 ± 1.3 (2.4 ± 1.5 [XEN] vs. 1.9 ± 1.2 [Phaco + XEN]) to 0.4 ± 0.9 (0.3 ± 0.8 [XEN] vs. 0.5 ± 0.9 [Phaco + XEN]) (-78.9%; p < 0.001). Complete success and qualified success were achieved in 29.0% and 31.0% of eyes, respectively. Needling revision was performed in 51 eyes (55.4%), and 26.1% underwent reoperations. Risk factors for surgical failure included male gender (odds ratio [OR]:3.6; p = 0.03), diagnosis of POAG (OR: 4.5; p < 0.01) and undergoing needling revision (OR: 4.6; p < 0.01). While the type of procedure had no effect on the outcomes of PEXG, POAG eyes undergoing combined surgery had significantly higher rates of failure (OR: 7.29; p = 0.023). Most patients stable at 12-month remained so through to 3 years.

CONCLUSIONS

At 3 years, XEN gel stent implantation achieved clinically significant IOP and medication reduction despite relatively high rates of needling and reoperations. Identifying patients at risk preoperatively may help optimize surgical outcomes.

Ahmed implant coated with poly(2-methacryloyloxyethyl phosphorylcholine) inhibits foreign body reactions in rabbit eyes

Purpose

Wound healing after Ahmed glaucoma valve (AGV) implantation often entails fibrosis as a foreign body reaction to the silicone plate. Poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) forms an antifouling surface that inhibits fibrosis during wound healing. In this study, we aimed to compare the effects of the implantation of AGV coated with PMPC (wPMPC) versus AGV without PMPC (woPMPC) in rabbits.

Methods

Six New Zealand White rabbit does underwent AGV implantation in both eyes. For each rabbit, one eye was randomly selected for implantation of AGV wPMPC and a conventional AGV (woPMPC) was implanted in the contralateral eye. Gross conjunctival vascularity was compared between the two groups at the first, second, and fourth weeks after surgery. The eyes were enucleated in four weeks and subjected to staining with hematoxylin and eosin and Masson’s trichrome stain. The fibrosis and inflammation status among the eye samples were compared by measuring the thickness of the fibrotic walls and counting the number of chronic inflammatory cells around the AGV. Counting of inflammatory cells and measuring fibrotic wall thickness were done in a blinded method to eliminate observer bias. Statistical analysis was performed using the Mann-Whitney U test.

Results

Gross and histological examinations revealed no toxic effects of PMPC. There were no apparent differences in overall conjunctival vascularity between the two groups at weeks 1, 2, and 4 after surgery. The average inflammatory cell counts were 14.3 ± 5.8 per slide and 27.3 ± 8.6 per slide in the wPMPC and woPMPC groups, respectively (p = 0.037). The average thicknesses of the fibrotic wall were 57.9 ± 11.3 μm and 81.5 ± 21.3 μm in the wPMPC and woPMPC groups, respectively (p = 0.025).

Conclusion

Compared to the woPMPC group, the number of inflammatory cells and fibrosis were significantly decreased in the wPMPC group.