The role of the immune system in conjunctival wound healing after glaucoma surgery

[Wound healing after trabeculectomy : What and when in postoperative aftercare?]

Excessive wound healing in filtering glaucoma surgery is a key factor for a failed surgery. After the introduction of trabeculectomy in the 1960s many factors associated with an increased fibrotic reaction were recognized and methods were developed to influence postoperative wound healing. These range from the perioperative use of anti-inflammatory drugs and antimetabolites to the use of newer chemical compounds that influence the morphology of postoperative fibroblast growth. In the routine clinical practice, the fine tuning of therapeutic decisions plays a decisive role in the success or failure of filtration surgery.

Safety and Efficacy of the Rho-Kinase Inhibitor (Ripasudil) in Bleb Needling after Trabeculectomy: A Prospective Multicenter Study

Ripasudil, a rho-associated protein kinase inhibitor ophthalmic solution, shows a protective effect in preventing excessive scarring in vitro. This study aims to evaluate the safety and efficacy of ripasudil for glaucoma patients submitted to the needling procedure. In this prospective, multicenter, single-arm study, we included 20 eyes of 20 patients with glaucoma who underwent the needling procedure without antimetabolites. All patients administered ripasudil after needling for three months. The primary endpoint of this study was the safety of ripasudil in patients, and the secondary endpoint was the change in IOP at 12 weeks after the needling procedure. No serious complications were found in the patients. One eye experienced pruritus and conjunctival follicle, while another eye had conjunctival follicle. These complications were transient and resolved quickly after discontinuation of ripasudil. The mean preoperative IOP was 14.6 ± 4.6 mmHg, which decreased to 11.0 ± 4.7 mmHg (p = 0.0062) at 1 week postoperatively. The IOP reduction effect continued to 12 weeks (11.8 ± 3.1 mmHg; p = 0.0448). The administration of the ROCK inhibitor, ripasudil, after the needling procedure is safe and effective in maintaining IOP for 12 weeks.

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.

A multicenter phase II study on the safety of rho-kinase inhibitor (ripasudil) with needling for the patients after trabeculectomy

Background

There is no established method of maintaining or reducing intra ocular pressure after the needling procedure for failing blebs post trabeculectomy. Regarding newer antihypertensive medications, ripasudil, which is a rho-associated protein kinase inhibitor ophthalmic solution, was able to prevent excessive scarring in vitro. This study aims to evaluate the safety of glaucoma patients submitted to the needling procedure and administered ripasudil for preventing scarring after the procedure. We also investigate the efficacy of ripasudil after needling for bleb failure through suppression of fibrosis to the bleb.

Methods

This study is a multicenter, open-label, single-arm, phase II trial to evaluate the safety and efficacy of ripasudil in glaucoma patients after the needling procedure. Forty patients who will undergo needling at least 3 months after trabeculectomy will be recruited in Hiroshima university hospital and Hiroshima eye clinic. All the patients will instill ripasudil two times per day for three months after the needling procedure. The primary endpoint is the safety of ripasudil.

Conclusions

We plan to establish the safety of ripasudil and to collect information involving the efficacy of ripasudil widely in this study.

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.

Differential effects of acetylsalicylic acid and mitomycin C on cytokine-induced Tenon's capsule myofibroblast transdifferentiation and activity: Implications for glaucoma surgery

Inflammation-driven scarring is a major contributor to surgical failure after subconjunctival bleb forming glaucoma surgery. The current gold standard anti-scarring adjuvant mitomycin C (MMC) has variable effectiveness and is associated with significant risks. Acetylsalicylic acid (ASA), when delivered locally, repurposes the typically pro-inflammatory cyclooxygenase (COX-2) signaling for the resolution of inflammation and mitigating inflammation-mediated fibrosis. The aim of this study is to compare the effects of ASA and MMC in an in vitro model of subconjunctival scarring. Glaucoma patient-derived Tenon's capsule fibroblasts (HTCFs) were treated with TGFβ1 (2 ng/mL) plus or minus ASA (1600 μg/ml), or MMC (0.05, 0.1, 0.2 mg/mL). In vitro collagen contraction, MTT, LDH, immunofluorescence, and Western blot assays were performed. To elucidate the mechanistic effects of ASA in TGFβ1-induced HTCFs, liquid chromatography tandem mass spectrometry (LC-MS/MS) was used to identify and measure pro-inflammatory and pro-resolving lipid mediator secretion. ASA was at least as effective as MMC in reducing TGFβ1-induced HTCF-mediated collagen contraction, metabolic activity, and pro-fibrotic protein expression, with less cytotoxicity. Within cytokine-activated HTCFs, ASA significantly impaired secretion of pro-inflammatory lipid mediators prostaglandin E2 and 6-keto-prostaglandin F1α and significantly increased secretion of the pro-resolving mediators 5-hydroxyeicosatetraenoic acid (HETE), 15-HETE and 18-hydroxyeicosapentaenoic acid (HEPE). ASA reduces cytokine-induced myofibroblast transdifferentiation in HTCFs, being non-inferior to MMC in vitro. ASA's effects are associated with a unique lipid mediator expression profile, suggesting that the ASA-induced resolution of inflammation may be a promising strategy to mitigate inflammation-mediated scarring and could offer a novel alternative as a surgical adjuvant.

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.

Anterior Segment-Optical Coherence Tomography Bleb Morphology Comparison in Minimally Invasive Glaucoma Surgery: XEN Gel Stent vs. PreserFlo MicroShunt

Background: The purpose of this study is to compare the morphology of six-month follow-up blebs created by a subconjunctival glaucoma surgical device (XEN45) to those created by a PreserFlo MicroShunt with a sub-Tenon insertion, utilizing AS-OCT. Methods: A retrospective study of 29 eyes who underwent XEN45 implantation and 29 eyes who underwent PreserFlo MicroShunt implantation. The patients were analyzed at 24 h, 1 week, 1 month, 3 months and 6 months. At each visit, the maturation and morphological alterations of the blebs were observed, as well as connections with the IOP. Results: In both groups, IOP showed significant reduction at all follow ups (p < 0.0001). In XEN group, the most common bleb morphology in the immediate postoperative was the subconjuntival separation type (42%) followed by the uniform type (34%), with a trend inversion at 6 month follow up (51% of uniform type). On the contrary, the most common morphology after PreserFlo was the multiple internal layer (55%), which showed a tendency to reduce over time and was substituted by the microcystic multiform, whose percentage increased over time (17% at day 1 vs. 44% at month 6). Uniform appearance was associated by the posterior episcleral fluid (PEF) lake presence. Both horizontal and vertical diameters significantly increased over time. Conclusion: XEN and PreserFlo implantation resulted in the production of diffuse blebs with different characteristics, which may influence IOP lowering capacity and bleb revisions necessity over time.

Anterior-segment optical coherence tomography of filtering blebs in the early postoperative period of ab externo SIBS microshunt implantation with mitomycin C: Morphological analysis and correlation with intraocular pressure reduction

PURPOSE

To analyse the morphological evolution of filtering blebs with anterior-segment OCT (AS-OCT) and its correlation with intraocular pressure after ab externo SIBS microshunt implantation with mitomycin C (MMC) during a 3-month follow-up period.

METHODS

Twenty-eight filtering blebs of 28 patients with open-angle glaucoma were measured horizontally and vertically in the sub-Tenon space with AS-OCT after ab externo SIBS microshunt implantation with MMC. The intraocular pressure (IOP) was monitored simultaneously at each visit. Maturation of and morphological changes in the blebs and correlations with the IOP were recorded.

RESULTS

The average median preoperative IOP of 20.7 (range, 12-30) mmHg decreased to 8.5 (range, 4-17), 8.9 (range, 5-17), 10.4 (range, 8-16) and 10.9 (range, 9-15) mmHg at 24 hr, 1 week, 1 month and 3 months, respectively (p < 0.001). A multiform morphology on AS-OCT prevailed at all time points, with a 3.5% rate of a uniform bleb morphology at the first week. The horizontal and vertical diameters of the blebs increased from baseline to the third month. The horizontal expansion (406 ± 127 μm on day 7, p = 0.04, 712 ± 211 μm on day 30, p = 0.02 and 952 ± 218 μm on day 90, p < 0.001) was greater than the vertical expansion (16 ± 18 μm, p = 0.3 on day 1, 63 ± 27 μm, p = 0.02 on day 30 and 137 ± 34 μm, p < 0.001 on day 90) without correlation with the IOP (r = -0.3, p = 0.2).

CONCLUSION

Anterior-segment OCT (AS-OCT) of the filtering blebs formed after ab externo SIBS microshunt implantation showed progressive horizontal and vertical expansion of the blebs in the sub-Tenon space, with a significant peak at the first month not significantly correlated with the decrease in the IOP.

Statin use and the reoperation rates in glaucoma filtration surgery - population-based cohort study

PURPOSE

To examine the association of systemic statin therapy and reoperation rate after glaucoma filtration surgery (GFS).

METHODS

This is a population-based, historic cohort study of 2705 eyes undergoing GFS in Finland between July 2009 and December 2016. GFSs were identified from national administrative healthcare registers. Baseline sociodemographic and health characteristics were documented. Reoperation rates of GFS subgroups were analysed, with statin users compared to non-users. The outcomes were modelled using a Poisson regression model adjusted for age, sex, education, statin use, chronic comorbidities, and cataract surgery with incident rate ratios (IRR) as the main outcome measure.

RESULTS

The cohort contained 2263 subjects with open-angle glaucoma (OAG), 823 men and 1440 women. Surgery was performed on 2705 eyes. First documented procedures: deep sclerectomy (DS) (n = 1601), trabeculectomy (TRE) (799) and glaucoma drainage device (GDD) implantation (305) respectively. In total, 438 secondary operations were performed during the 7.5-year (median 2.25 years) follow-up period. The reoperation rates were 19% after DS, 12% after TRE, and 13% after GDD. Of the surgical procedures, 32% were performed on eyes of patients receiving statin therapy. Statin users showed no difference in reoperation rates (IRR 1.06, CI 0.82-1.37). In subgroups, no difference was observed in the reoperation rates adjusted with statin use after filtration surgery (DS, TRE) (IRR 1.06, CI 0.8-1.40) or GDD implantation (0.57, CI 0.20-1.63).

CONCLUSION

Systemic statin therapy among surgically treated OAG patients had no impact on secondary surgery rates following DS, TRE or GDD implantation.

Potential roles of the IL-6 family in conjunctival fibrosis

Elevated intraocular pressure (IOP) is a significant risk factor for vision loss due to glaucoma, which is a major cause of blindness worldwide. Glaucoma filtration surgery (GFS) is an important method to reduce IOP by guidance of aqueous humor into a newly built filtration bleb in the conjunctiva; management of the wound healing mechanism is essential for the success of GFS. Here, we investigated the roles of interleukin (IL)-6 family members during the wound healing process after GFS. At the surgical site, the expression levels of genes encoding IL-6, oncostatin M (OSM), their receptors, and collagen I were elevated at 3 h after GFS, whereas the levels of genes encoding transforming growth factor (TGF)-β, α-smooth muscle actin (SMA), type IV collagen, and fibronectin were elevated at 3 days after GFS. IL-6 trans-signaling and OSM signaling suppressed TGF-β-induced expression of α-SMA and collagen IV, as well as activation of the non-canonical TGF-β pathway, suggesting that IL-6 and OSM may aid in controlling the phase transition from inflammation to proliferation and remodeling. The suppressive effects of OSM were accompanied by STAT3 activation, such that STAT1 function was complementary to STAT3. Taken together, these observations indicated that IL-6 family members constitute early response genes after GFS, which can suppress TGF-β-induced expression of late response genes at the surgical site after GFS.

Changes in the morphology of the hyperemic blebs in eyes undergone trabeculectomy with mitomycin C after injection of triamcinolone acetonide during one-year follow-up

PURPOSE

To track changes in the morphology of hyperemic blebs in eyes undergone trabeculectomy with mitomycin C 0.02% (MMC) after triamcinolone acetonide (TA) injection.

METHODS

A total of 30 eyes of 30 patients with localized or diffuse hyperemia after trabeculectomy with MMC were enrolled in this prospective interventional case series. Two milligrams of TA were injected at the site of maximal injection. Bleb morphology was graded using Indiana Bleb Appearance Grading Scale (IBAGS), and the Moorfields Bleb Grading System (MBGS) 1 week, 1 month, 3 months, 6 months, and 1 year after injection. Failure was defined as intraocular pressure (IOP) more than predefined target IOP for each eye, need for an additional surgical procedure, IOP less than 6 mmHg, and loss of Light Perception (LP) vision.

RESULTS

A total of 27 patients completed a 1-year follow-up period and were included in the final analysis. The mean time interval from trabeculectomy to injection of TA was 5.98 ± 2.57 weeks. The bleb height and vascularity in the IBAGS system decreased significantly after the intervention (p < 0.05), with an increase in bleb extension (p = 0.006). Using MBGS, the bleb area did not change significantly following TA injection (p = 0.056) but its height and vascularity significantly decreased in both central and peripheral areas and the surrounding conjunctiva (p = 0.032). The development of a mature cataract was the only complication that could be attributed to TA injection.

CONCLUSION

Injection of TA in hyperemic failing blebs improves bleb morphology by decreasing vascularity and height while increasing the extent with an acceptable safety profile.

The Role of Biologically Active Aqueous Humor Molecules of the Anterior Chamber and Lacrimal Fluid in the Implementation of the Hypotensive Effect of Non-Penetrating Deep Sclerectomy

To date, the factors affecting the course of the reparative process after non-penetrating deep sclerectomy (NPDS) have not been fully determined. There is no systematic information about the regulatory role of the cytokines TGF-β, IL-6, IL-8 and MMP-9, VEGF A 121 and 165 in the formation mechanisms of the newly created pathways consistency of intraocular aqueous humor outflow.

Purpose. To determine possible ways of impact of biologically active aqueous humor molecules of the anterior chamber and lacrimal fluid on the hypotensive effect of non-penetrating deep sclerectomy.

Methods. A prospective study of 65 patients with open-angle glaucoma before and 12 months after NPDS and 22 patients without eye hydrodynamic disorders with the determination of the initial concentrations of biologically active molecules in the lacrimal fluid and aqueous humor of the anterior chamber. Twelve months after NPDS all patients were divided into three groups, depending on the hypotensive effect of the operation, according to the criteria.

Results. Multivariate discriminant analysis showed the greatest inter-group differences, calculated by the square of the Mahalanobis distance, between group 3 with no hypotensive effect of NPDS and the control group (R2 = 8.48, p = 0.001). The most informative features that determine the differences between the 4 groups in the total population, calculated according to the Fischer F-test, were MMP-9 (F = 14.7, p = 0.001) and TGF-β (F = 7.08, p = 0.001) in the aqueous humor of the anterior chamber. In pairwise comparison of groups 1 and 2, the maximum level of significance according to the F-criterion was characteristic of the level of tear IL-6 (F = 21.25, p = 0.001), with approximately equal degree – IL-8 (F = 7.85, p = 0.001) and VEGF (F = 7.12, p = 0.001), to a lesser extent TGF of aqueous humor (F = 4.43, p = 0.001) and MMR-9 (F = 2.23, p = 0.001). Between groups 1–3, the maximum differences according to the Fisher criterion were observed in the IL-8 (F = 20.99, p = 0.001), TGF (F = 8.75, p = 0.001) and to a lesser extent – TGF (F = 5.83, p = 0.001).

Conclusion. The analysis of the obtained data showed the decisive role of the imbalance of proinflammatory cytokines, signaling proteins with prolymphoangiogenic activity, and MMP-9 in the aqueous humor of the anterior chamber, as well as in the initial state of the lacrimal fluid in the postoperative healing processes after NPDS. 

The effect of halofugınone and pirfenidone on wound healing in experimental glaucoma filtration surgery

PURPOSE

To investigate the effects of halofuginone and pirfenidone on wound healing in experimental glaucoma filtration surgery (GFS).

STUDY DESIGN

Animal experimentation.

METHODS

A total of 42 male New Zealand albino rabbits were separated into 6 equal groups. A limbal-based trabeculectomy was performed on 5 groups, and Group I (control group) underwent no surgery and received no postoperative medication. For Group II (sham group), 1 drop 0.9% NaCl was instilled qid for 14 days. For Group III, 1% topical corticosteroid (prednisolone acetate) was instilled 1 drop qid for 14 days. For Group IV, 0.4mg/mL mitomycin-C (MMC) was applied intraoperatively to the region of the scleral flap. For Group V, 0.5% pirfenidone was instilled 1 drop qid for 14 days postoperatively. For Group VI, a sponge soaked in 10ng/mL halofuginone was applied to the surgical region for 3 mins. In addition, 1% topical corticosteroid was instilled ×1 drop qid for 14 days postoperatively for Groups IV, V and VI. After 14 days, sections prepared from the bleb regions of the enucleated eyes were evaluated histopathologically and immunohistochemically. Statistical analyses of the study were performed with Kruskal-Wallis variance analysis and the Mann-Whitney U test.

RESULTS

With regard to fibroblasts, suppression of the number of mononuclear cells and immunohistochemical staining intensity of transforming growth factor-b (TGF-β), fibroblast growth factor-b (FGF-β) and platelet derived growth factor (PDGF), the corticosteroid, MMC, pirfenidone and halofuginone groups were seen to exhibit more effect than the sham group (P<0.05). Compared to the pirfenidone and fuginone groups, inhibition of fibroblast and monocyte proliferation was determined to be lower in the MMC group (P<0.05). The intensity of TGF-β and FGF-β staining was seen to be lower in these two treatment groups than in the MMC group (P<0.05).

CONCLUSIONS

Halofuginone and pirfenidone may be used as effective alternative agents in delaying wound healing in glaucoma filtration surgery.

Effect of oral statin use on mitomycin-C augmented trabeculectomy outcomes

Purpose

The effect of statins on wound healing is controversial, and their effect on trabeculectomy outcomes remains unclear. This study aimed to examine the relationship between oral statin use and trabeculectomy outcomes.

Methods

Medical records of patients who underwent primary mitomycin-C augmented trabeculectomy with 2 years of follow-up were reviewed. Pre- and postoperative intraocular pressures (IOP) and numbers of medications, subconjunctival 5-fluorouracil (5-FU) injections, and bleb-needling procedures were compared between statin users and nonusers. Failure was defined as an eye that failed to achieve a 20% lowering of IOP from baseline or had an IOP > 21 mm Hg, as well as an eye that required further surgical intervention, developed hypotony, or had no light perception visual acuity.

Results

In total, 158 subjects were enrolled, with 47 eyes from statin users and 111 eyes from statin nonusers. The 24-month cumulative probability of failure was 78.7% for statin users and 60.4% for nonusers (P = .013). Cox proportional-hazards modeling showed a significantly higher hazard risk in statin users (adjusted hazard ratio 1.61, P = .026). There were no significant between-group differences in mean IOPs or number of medications (both P > .05) at 24 months. Multivariable Poisson regression analysis that statin use was associated with increased numbers of 5-FU injections (P = .014) and bleb-needling procedures (P = .031).

Conclusions

This study demonstrated that oral statin use was associated with higher rates of trabeculectomy failure and increased numbers of 5-FU injections and bleb-needling procedures.

Novel Drug Delivery Systems Fighting Glaucoma: Formulation Obstacles and Solutions

Glaucoma is considered to be one of the biggest health problems in the world. It is the main cause of preventable blindness due to its asymptomatic nature in the early stages on the one hand and patients' non-adherence on the other. There are several approaches in glaucoma treatment, whereby this has to be individually designed for each patient. The first-line treatment is medication therapy. However, taking into account numerous disadvantages of conventional ophthalmic dosage forms, intensive work has been carried out on the development of novel drug delivery systems for glaucoma. This review aims to provide an overview of formulation solutions and strategies in the development of in situ gel systems, nanosystems, ocular inserts, contact lenses, collagen corneal shields, ocular implants, microneedles, and iontophoretic devices. The results of studies confirming the effectiveness of the aforementioned drug delivery systems were also briefly presented.

Pluripotent epigenetic regulator OBP-801 maintains filtering blebs in glaucoma filtration surgery model

Inhibition of fibrosis is indispensable for maintaining filtering blebs after glaucoma filtration surgery (GFS). The purpose of this study was to investigate the ability of a pluripotent epigenetic regulator OBP-801 (OBP) to ameliorate extracellular matrix formation in a rabbit model of GFS. Rabbits that underwent GFS were treated with OBP. The gene expression profiles and intraocular pressure (IOP) were monitored until 30 postoperative days. The bleb tissues were evaluated for tissue fibrosis at 30 postoperative days. In in vitro models, OBP interfered the functions of diverse genes during the wound-healing process. In in vivo GFS models, the expressions of TGF-β3, MMP-2, TIMP-2 and 3, LOX, COL1A and SERPINH1 were significantly inhibited at 30 postoperative days in the OBP group compared with those in the vehicle control group. OBP treatment involving subconjunctival injection or eye drops showed no adverse effects, and reduced levels of α-SMA and collagen deposition at the surgical wound site. OBP maintained the long-lived bleb without scar formation, and IOP was lower at 30 postoperative days compared with the vehicle control group. These findings suggest that OBP is an effective and useful candidate low-molecular-weight agent for improving wound healing and surgical outcomes in a rabbit model of GFS.

A new, minimally invasive procedure for dogs with encapsulated Ahmed drainage implants and elevated intraocular pressures: A case series

OBJECTIVE

To describe a novel, minimally invasive method for re-establishing aqueous humor outflow in dogs with refractory glaucoma after fibrous encapsulation of their Ahmed drainage implants.

PROCEDURE

Three dogs (4 eyes) underwent trans-capsular implantation of an Alcon EX-PRESS^® glaucoma filtration device under sedation (2 dogs) or general anesthesia (1 dog). After rotating the eye downwards, a 2 mm incision was made in the conjunctiva/Tenon's capsule overlying the encapsulated Ahmed plate, and later closed with absorbable suture. All eyes received subconjunctival mitomycin-C 0.02 mg.

RESULTS

Mean post-operative follow-up was 341 days (range: 77-530). All eyes were hypertensive pre-operatively (mean IOP: 31.25 ± 7.14 mmHg) despite receiving topical latanoprost (4/4), timolol (4/4), carbonic anhydrase inhibitors (4/4), and demecarium bromide (2/4). Two eyes (dogs 1 and 2) were visual pre-operatively, while 2 eyes (dog 3) displayed equivocal or no vision. Post-operatively, all eyes received timolol and a carbonic anhydrase inhibitor. Other anti-hypertensive medications were discontinued. Immediately following surgery, all eyes were mildly hypotensive (mean IOP: 5.75 ± 1.71 mm Hg). Two of 4 eyes were normotensive and visual until days 90 (dog 2) and 530 (dog 1) (IOP range: 10-16 mm Hg). One eye (dog 3) was normotensive for approximately 150 days, and then hypertension returned. One eye (dog 3) from the start displayed severe uveitis, hypertensive episodes, and was phthisical by the end of follow-up.

CONCLUSIONS

Trans-capsular EX-PRESS^® implantation is a minimally invasive procedure for treatment of refractory glaucoma in dogs with encapsulated Ahmed drainage implants, and further investigation is warranted.

Alteration of gene expression in mice after glaucoma filtration surgery

To clarify the early alterations of gene expression using a mouse model of glaucoma filtration surgery, we carried out microarray expression analysis. Using BALB/c mice, a filtration surgery model was made by incision of the limbal conjunctiva, followed by the insertion of a 33G needle tip into the anterior chamber, and 11-0 nylon sutures. Subgroups of mice were treated intraoperatively with 0.4 mg/ml mitomycin-C (MMC). At day 3 after surgery the bleb was maintained. The bleb region tissue was sampled 3 days after the filtration surgery, and gene expression analysis was carried out using a mouse Agilent 8 × 60 K array. We found 755 hyperexpressed transcripts in the bleb region compared to control conjunctiva. The hyperexpressed transcripts included epithelial cell metaplasia-related (Il1b, Krt16, Sprr1b), inflammation-related (Ccl2, Il6) and wound healing-related (Lox, Timp1) genes. We also found downregulation of a goblet cell marker gene (Gp2) in the bleb conjunctiva. MMC treatment suppressed elastin (Eln) gene expression and enhanced keratinization-related gene expression (Krt1, Lor) in the bleb region. Our results suggest the importance of epithelial wound healing after filtration surgery, and this filtration surgery model will be a useful tool for further pathophysiological analysis.

Inhibition of post-trabeculectomy fibrosis via topically instilled antisense oligonucleotide complexes co-loaded with fluorouracil

Trabeculectomy is the mainstay of surgical glaucoma treatment, while the success rate was unsatisfying due to postoperative scarring of the filtering blebs. Clinical countermeasures for scar prevention are intraoperative intervention or repeated subconjunctival injections. Herein, we designed a co-delivery system capable of transporting fluorouracil and anti-TGF-β2 oligonucleotide to synergistically inhibit fibroblast proliferation via topical instillation. This co-delivery system was built based on a cationic dendrimer core (PAMAM), which encapsulated fluorouracil within hydrophobic cavity and condensed oligonucleotide with surface amino groups, and was further modified with hyaluronic acid and cell-penetrating peptide penetratin. The co-delivery system was self-assembled into nanoscale complexes with increased cellular uptake and enabled efficient inhibition on proliferation of fibroblast cells. In vivo studies on rabbit trabeculectomy models further confirmed the anti-fibrosis efficiency of the complexes, which prolonged survival time of filtering blebs and maintained their height and extent during wound healing process, exhibiting an equivalent effect on scar prevention compared to intraoperative infiltration with fluorouracil. Qualitative observation by immunohistochemistry staining and quantitative analysis by Western blotting both suggested that TGF-β2 expression was inhibited by the co-delivery complexes. Our study provided a potential approach promising to guarantee success rate of trabeculectomy and prolong survival time of filtering blebs.

Matrix Metalloproteinases Retain Soluble FasL-mediated Resistance to Cell Death in Fibrotic-Lung Myofibroblasts

A prominent feature of obstructed tissue regeneration following injury in general, and fibrotic lung tissue in particular, is fibroblast proliferation and accumulation. The Fas/FasL apoptotic pathway has been shown to be involved in human idiopathic pulmonary fibrosis (IPF) and bleomycin-induced lung fibrosis in rodents. We previously showed that in normal injury repair, myofibroblasts' accumulation is followed by their decline by FasL⁺ T cell-induced cell death. In pathological lung fibrosis, myofibroblasts resist cell death and accumulate. Like other members of the tumor necrosis factor (TNF) family, membrane-bound FasL can be cleaved from the cell surface to generate a soluble form (sFasL). Metalloproteinases (MMPs) are known to convert the membrane-bound form of FasL to sFasL. MMP-7 knockout (KO) mice were shown to be protected from bleomycin (BLM)-induced lung fibrosis. In this study, we detected increased levels of sFasL in their blood serum, as in the lungs of patients with IPF, and IPF-lung myofibroblast culture medium. In this study, using an MMP-inhibitor, we showed that sFasL is decreased in cultures of IPF-lung myofibroblasts and BLM-treated lung myofibroblasts, and in the blood serum of MMP-7KO mice. Moreover, resistant fibrotic-lung myofibroblasts, from the lungs of humans with IPF and of BLM-treated mice, became susceptible to T-cell induced cell death in a co-culture following MMP-inhibition- vs. control-treatment or BLM-treated MMP-7KO vs. wild-type mice, respectively. sFasL may be an unrecognized mechanism for MMP-7-mediated decreased tissue regeneration following injury and the evolution of lung fibrosis.

Modified Cortex Mori Capsules improving the successful rate of functional filtering blebs after reclinical glaucoma filtering surgery

BACKGROUND

The major reason for filtering bleb failure or scarring of the bleb site is due to excessive scarring after glaucoma filtration surgery in the clinic. Traditional Chinese medicine has preeminence in the prevention of fibrosis formation through the regulation of systemic circulation and improvement of the properties of the inflammatory cells in the blood.

AIM

To examine the clinical efficacy of using the Modified Cortex Mori Capsules (MCMC; Chinese name: Jiawei Sangbaipi Capsules) in the success rate of functional filtering blebs after glaucoma filtering surgery in clinical patients.

METHODS

Sixty resurgery glaucoma patients were randomly divided into two groups: 30 patients in surgery with the placebo group and 30 patients in surgery with the MCMC group. Patients took either the placebo or the MCMC 2 wk before and after surgery. Postoperative morphology and function filtering bleb, visual acuity, intraocular pressure, postoperative complications, the success rate of filtration surgery and clinical efficacy were observed.

RESULTS

Fifty patients completed the study. The percentage of functional filtering blebs in the surgery plus MCMC group was 84% at 6 mo after surgery, which was higher than surgery plus placebo group (64%, P < 0.05). The surgical success rate in the MCMC and placebo groups were 79% ± 8.3% and 57% ± 10.6% respectively (P < 0.05). The visual acuity, intraocular pressure and the postoperative complications in the two groups had no significant differences.

CONCLUSION

Glaucoma filtering surgery while taking MCMC not only reduced excessive scar formation and increased the success rate of functional filtering blebs but also improved the success of glaucoma filtration operations.

Clinical and Immunological Evaluation of the Effectiveness of Non-Penetrating Deep Sclerectomy in the Early Postoperative Period

Today the mechanisms of pathological scarring and inconsistency of the intraocular fluid outflow pathways after nonpenetrating deep sclerectomy (NPDS), reducing its effectiveness, have not yet been determined. There is no systematic information about the regulatory role of cytokine TGF-β and MMP-9 in the mechanisms of formation of the newly created intraocular fluid outflow pathways.

Aim: to assess changes in the clinical and immunological status of patients with open-angle glaucoma after NPDS in the early postoperative period.

Methods. A prospective examination of 26 patients with open-angle glaucoma before and in 1 month after NPDS with determination of concentration of TGF-β and MMP-9 in tear humor. One month after NPDS, all patients were divided into two groups depending on the effect of the operation achieved according to the developed criteria.

Results. Before the operation, tears TGF-β values in group 1 exceeded baseline values of group 2 by 1.4 times, the initial content of MMP-9 in tears in both groups was comparable. After the operation, in group 1, a moderate increase in the concentration of tears TGF-β by 1.3 times and a significant increase in the concentration of tears MMP-9 in 4.6 times compared with baseline values were revealed. In patients of group 2, after NPDS, there was a significant increase in the concentration of tears TGF-β, on average, 2.4 times relative to preoperative values, the content of MMP-9 did not significantly change.

Conclusion. 1 month after NPDS, an imbalance in the concentration of TGF-β and MMP-9 in tears was detected in patients of the two groups that have fundamental clinical differences in the hypotensive effect and the formation of postoperative intraocular fluid outflow pathways.

All‑trans‑retinoic acid modulates TGF‑β‑induced apoptosis, proliferation, migration and extracellular matrix synthesis of conjunctival fibroblasts by inhibiting PI3K/AKT signaling

Conjunctival fiber generation is implicated in a wide spectrum of ocular diseases. Conjunctival wound healing is characterized by inflammation followed by re‑epithelialization, synthesis of new extracellular matrix (ECM), wound contraction and subconjunctival scar formation. The primary cause for the failure of glaucoma filtration surgery results from the excessive scarring of the filtering bleb. All‑trans‑retinoic acid (ATRA), a derivative of vitamin A, is a potent regulator of ECM synthesis, growth and differentiation. Following a previous study, which revealed that ATRA could inhibit transforming growth factor‑β‑induced human conjunctival fibroblast (HConF)‑mediated collagen gel contraction, the present study aimed to investigate the effects of ATRA on HConF migration, apoptosis, proliferation and ECM synthesis. To achieve this, the present study used Transwell migration, wound healing and Cell Counting Kit‑8 assays, flow cytometry and western blot analysis. In addition, the present study aimed to elucidate the mechanism of ATRA in mediating resistance to conjunctival scar formation. ATRA treatment resulted in an increased level of HConF apoptosis, reduced proliferation and migration, decreased collagen I and fibronectin expression, and decreased phosphorylation of PI3K and AKT. Thus, the present study showed a role for ATRA in inhibiting HConF migration, proliferation and ECM synthesis, and in promoting HConF apoptosis through the inhibition of the PI3K/AKT signaling pathway.

Effect of cytoglobin overexpression on extracellular matrix component synthesis in human tenon fibroblasts

BACKGROUND

Conjunctival filtering bleb scar formation is the main reason for the failure of glaucoma filtration surgery. Cytoglobin (Cygb) has been reported to play an important role in extracellular matrix (ECM) remodeling, fibrosis and tissue damage repairing. This study aimed to investigate the role of Cygb in anti-scarring during excessive conjunctival wound healing after glaucoma filtration surgery.

METHODS

Cygb was overexpressed in human tenon fibroblasts (hTFs) by transfecting hTFs with lentiviral particles encoding pLenti6.2-FLAG-Cygb. Changes in the mRNA and protein levels of fibronectin, collagen I, collagen III, TGF-β1, and HIF1α were determined by RT-PCR and western blotting respectively.

RESULTS

After Cygb overexpression, hTFs displayed no significant changes in visual appearance and cell counts compared to controls. Whereas, Cygb overexpression significantly decreased the mRNA and protein expression levels of collagen I, collagen III and fibronectin compared with control (p < 0.01). There was also a statistically significant decrease in the mRNA and protein levels of TGF-β1 and HIF-1α in hTFs with overexpressed Cygb compared with control group (p < 0.05).

CONCLUSION

Our study provided evidence that overexpression of Cygb decreased the expression levels of fibronectin, collagen I, collagen III, TGF-β1 and HIF-1α in hTFs. Therefore, therapies targeting Cygb expression in hTFs may pave a new way for clinicians to solve the problem of post-glaucoma surgery scarring.

[Glaucoma surgery: from traditional filtration techniques to modern principles of bioengineering]

The article reviews the history of glaucoma surgery and analyses the connection between the accumulation of knowledge on glaucoma progression and the emergence of effective surgical treatment methods based on glaucoma pathogenesis. It also describes modern principles of preventing filtering bleb scarring. Particular attention is devoted to biodegradable collagen matrix implants.

MEK inhibition prevents TGF‑β1‑induced myofibroblast transdifferentiation in human tenon fibroblasts

Subconjunctival fibrosis represents the primary cause of postoperative failure of trabeculectomy, and at present there is a lack of effective intervention strategies. The present study aimed to investigate the effect of the mitogen‑activated protein kinase kinase (MEK) inhibitor U0126 on human tenon fibroblast (HTF) myofibrosis transdifferentiation, and to illuminate the underlying molecular mechanisms involved. It was demonstrated that U0126 significantly inhibited the proliferation, migration and collagen contraction of HTFs stimulated with TGF‑β1. In addition, U0126 largely attenuated the TGF‑β1‑induced conversion of HTFs into myofibroblasts, as indicated by a downregulation of the mRNA and protein expression of α‑smooth muscle actin and zinc finger protein SNAI1, and by ameliorating the 3D‑collagen contraction response. Mechanistically, U0126 suppressed the TGF‑β1‑stimulated phosphorylation of mothers against decapentaplegic homolog 2/3, P38 mitogen‑activated protein kinase and extracellular signal‑regulated kinase 1/2, indicating that U0126 may inhibit HTF activation through the canonical and non‑canonical signaling pathways of TGF‑β1. Therefore, U0126 exhibits a potent anti‑fibrotic effect among HTFs, and the inhibition of MEK signaling may serve as an alternative intervention strategy for the treatment of trabeculectomy‑associated fibrosis.

Potential Effect of Cyclophosphamide on Bleb Survival in Five Patients with Multiple Sclerosis Who Underwent Glaucoma Surgery

INTRODUCTION

The purpose of this case series was to report the potential role of cyclophosphamide (CY) on bleb survival and to evaluate the safety of the trabeculectomy procedure under immunosuppressant systemic therapy.

CASE SERIES

Five eyes of five patients with unresponsive to intraocular pressure (IOP) lowering medication, progressive glaucoma, underwent mytomicin C (MMC) augmented phaco-trabeculectomy, performed by the same surgeon, A.G., during the period from May 2015 to January 2016. All patients were treated with low doses of systemic CY at the time of surgery, to control their relapsing progressive multiple sclerosis (MS) form.

RESULTS

During a mean follow-up period of 20.6 ± 8.1 months, for cases of "complete success" (when the IOP was < 15 mmHg without glaucoma therapy) were observed, while one case was classified as a "qualified success" since the IOP was ≤ 15 mmHg with β-blocker drops. There were no bleb infections, nor bleb-related complications.

CONCLUSION

This study reports the safety of performing the filtration surgical procedure under immunosuppressant systemic therapy and provides a possible explication of CY anti-fibrotic mechanism and its possible role on bleb survival. Our findings may suggest new perspectives of study in this field.

NPPB modulates apoptosis, proliferation, migration and extracellular matrix synthesis of conjunctival fibroblasts by inhibiting PI3K/AKT signaling

When treating glaucoma, excessive scar tissue reactions reduce the postoperative survival rate of the filtering bleb. Accumulating evidence has demonstrated that the proliferation, migration and extracellular matrix (ECM) synthesis of fibroblasts are important molecular mechanisms underlying scar formation. Recent evidence has demonstrated that chloride channels play an important role in controlling cell proliferation, apoptosis, migration and the cell cycle process in several cell types, but the effects of chloride channels on conjunctival fibroblasts have not be studied. The aim of the present study was to investigate the effects of the chloride channel blocker 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) on cell proliferation, apoptosis, migration, cell cycle progression and ECM synthesis in human conjunctival fibroblasts (HConFs), and to further investigate the mechanism of resistance to scar formation following glaucoma filtration surgery. HConFs were exposed to NPPB or lubiprostone. Cell proliferation and viability was evaluated using the Cell Counting Kit-8. Cell migration was measured using Transwell migration and scratch‑wound assays. Flow cytometry was used to study apoptosis and cell cycle progression. Quantitative polymerase chain reaction and western blot analyses were performed to determine mRNA and protein expression levels, respectively. Following NPPB treatment, HConFs exhibited reduced proliferation and migration, along with increased apoptosis. NPPB also inhibited cell cycle progression by arresting cells in the G0̸G1 phase and reducing collagen I and fibronectin expression, as well as the phosphorylation of phosphoinositide 3-kinase (PI3K) and protein kinase B (AKT). However, lubiprostone treatment exerted the opposite effects on HConFs. Therefore, NPPB treatment inhibited proliferation, migration, cell cycle progression and synthesis of the ECM, while promoting apoptosis in HConFs, by inhibiting the PI3K̸AKT signaling pathway.

Genotype-Phenotype Associations of IL6 and PRG4 With Conjunctival Fibrosis After Glaucoma Surgery

Importance

Postsurgical fibrosis is a critical determinant of the long-term success of glaucoma surgery, but no reliable biomarkers are currently available to stratify the risk of scarring.

Objective

To compare the clinical phenotype of patients with conjunctival fibrosis after glaucoma surgery with candidate gene expression tissue biomarkers of fibrosis.

Design, Setting, and Participants

In this cross-sectional study, 42 patients were recruited at the time of glaucoma surgery at the Moorfields Eye Hospital from September 1, 2014, to September 1, 2016. The participants were divided into those with fibrosis and those without fibrosis.

Main Outcomes and Measures

Genotype-phenotype correlations of the IL6 or PRG4 gene and detailed clinical phenotype. The IL6 and PRG4 protein expression in conjunctival tissues was also assessed using in situ immunohistochemical analysis. Central bleb area, maximal bleb area, and bleb height were graded on a scale of 1 to 5 (1 indicating 0%; 2, 25%; 3, 50%; 4, 75%; and 5, 100%). Bleb vascularity was graded on a scale of 1 to 5 (1 indicating avascularity; 2, normal; 3, mild; 4, moderate; and 5, severe hyperemia).

Results

A total of 42 patients were recruited during the study period; 28 participants (67%) had previously undergone glaucoma surgery (fibrotic group) (mean [SD] age, 43.8 [3.6 years]; 16 [57%] female; 22 [79%] white), and 14 participants (33%) had not previously undergone glaucoma surgery (nonfibrotic group) (mean [SD] age, 47.7 [6.9] years; 4 [29%] female; 9 [64%] white). The fibrotic group had marked bleb scarring and vascularization and worse logMAR visual acuity. The mean (SD) grades were 1.4 (0.1) for central bleb area, 1.4 (0.1) for bleb height, and 3.4 (0.2) for bleb vascularity. The IL6 gene was upregulated in fibrotic cell lines (mean, 0.040) compared with nonfibrotic cell lines (mean, 0.011) (difference, 0.029; 95% CI, 0.015-0.043; P = .003). The PRG4 gene was also downregulated in fibrotic cell lines (0.002) compared with nonfibrotic cell lines (mean, 0.109; difference, 0.107; 95% CI, 0.104-0.110; P = .03). The study found a strong correlation between the IL6 gene and the number of glaucoma operations (r = 0.94, P < .001) and logMAR visual acuity (r = 0.64, P = .03). A moderate correlation was found between the PRG4 gene and the number of glaucoma operations (r = -0.72, P = .005) and logMAR visual acuity (r = -0.62, P = .03).

Conclusions and Relevance

IL6 and PRG4 represent potential novel tissue biomarkers of disease severity and prognosis in conjunctival fibrosis after glaucoma surgery. Future longitudinal studies with multiple postoperative measures are needed to validate the effect of these potential biomarkers of fibrosis.

Custom RT-qPCR-array for glaucoma filtering surgery prognosis

Excessive subconjunctival scarring is the main reason of failure of glaucoma filtration surgery. We analyzed conjunctival and systemic gene expression patterns after non penetrating deep sclerectomy (NPDS). To find expression patterns related to surgical failure and their correlation with the clinical outcomes. This study consisted of two consecutive stages. The first was a prospective analysis of wound-healing gene expression profile of six patients after NPDS. Conjunctival samples and peripheral blood samples were collected before and 15, 90,180, and 360 days after surgery. In the second stage, we conducted a retrospective analysis correlating the late conjunctival gene expression and the outcome of the NPDS for 11 patients. We developed a RT-qPCR Array for 88 key genes associated to wound healing. RT-qPCR Array analysis of conjunctiva samples showed statistically significant differences in 29/88 genes in the early stages after surgery, 20/88 genes between 90 and 180 days after surgery, and only 2/88 genes one year after surgery. In the blood samples, the most important changes occurred in 12/88 genes in the first 15 days after surgery. Correspondence analyses (COA) revealed significant differences between the expression of 20/88 genes in patients with surgical success and failure one year after surgery. Different expression patterns of mediators of the bleb wound healing were identified. Examination of such patterns might be used in surgery prognosis. RT-qPCR Array provides a powerful tool for investigation of differential gene expression wound healing after glaucoma surgery.

Personalized Medicine in Ocular Fibrosis: Myth or Future Biomarkers

Significance: Fibrosis-related events play a part in the pathogenesis or failure of treatment of virtually all the blinding diseases around the world, and also account for over 40% of all deaths. It is well established that the eye and other tissues of some group of patients, for example Afro-Caribbean people, scar worse than others. However, there is a current lack of reliable biomarkers to stratify the risk of scarring and postsurgical fibrosis in the eye.

Recent Advances: Recent studies using genomics, proteomics, metabolomics, clinical phenotyping, and high-resolution in vivo imaging techniques have revealed potential novel biomarkers to identify and stratify patients at risk of scarring in different fibrotic eye diseases.

Critical Issues: Most of the studies, to date, have been done in animals or small cohorts of patients and future research is needed to validate these results in large longitudinal human studies. Detailed clinical phenotyping and effective biobanking of patient tissues will also be critical for future biomarker research in ocular fibrosis.

Future Directions: The ability to predict the risk of scarring and to tailor the antifibrotic treatment regimen to each individual patient will be an extremely useful tool clinically to prevent undertreating, or exposing patients to unnecessary treatments with potential side effects. An exciting future prospect will be to use new advances in genotyping, namely next-generation whole genome sequencing like RNA-Seq, to develop a customized gene chip in ocular fibrosis. Successful translation of future biomarkers to benefit patient care will also ultimately require a strong collaboration between academics, pharmaceutical, and biotech companies.

Early Aqueous Suppressant Therapy on Hypertensive Phase Following Glaucoma Drainage Device Procedure: A Randomized Prospective Trial

PURPOSE

To prospectively evaluate the effect of early aqueous suppression (therapy) on hypertensive phase (HP) and intraocular pressure (IOP) control after implantation of silicone Ahmed glaucoma valve (AGV).

MATERIALS AND METHODS

Patients who underwent AGV implantation were randomized to initiate therapy (including β-blockers, α-agonists, or carbonic anhydrase inhibitors) when postoperative IOP>10 mm Hg (low-IOP initiation group) or >17 mm Hg (moderate-IOP initiation group). HP was defined as an IOP>21 mm Hg during the first 6 postoperative months, after an initial IOP reduction to <22 mm Hg in the first postoperative week. Primary outcome measures included the occurrence of HP and IOP control.

RESULTS

Fifty-two eyes (50 patients) underwent AGV implantation. Average follow-up was 21.9±10.7 months. HP was observed in 21 eyes (40.4%) with average peak IOP of 30±8 mm Hg, onset at 32±30 days, and duration of 15±32 days. One year postoperatively, those eyes with HP had higher IOP than eyes that did not develop HP (15.1±5.2, 11.4±4.3, respectively; P=0.021) and required more additional glaucoma surgeries (28.6%, 3.2%, respectively; P=0.013). The peak IOP at week 3 postoperatively in the low-IOP initiation group (26 eyes) was significantly lower than in the moderate-IOP initiation group (26 eyes; 15.7±3.6, 20.6±8.9, respectively; P=0.012). Eyes with therapy started after HP onset had significantly higher postoperative IOP from 2 to 4 months. Therapy initiated before the development of HP was not associated with a higher complication rate.

CONCLUSIONS

Aqueous suppression initiated in the early postoperative period while IOPs were still in the low-teens and was able to reduce the incidence of IOP spike associated with the HP without an increased complication rate.

Development of bioresorbable bilayered systems for application as affordable wound dressings

The objective of this work was the preparation and evaluation of a bioresorbable bilayered system for application in the treatment of dermal lesions. The system was based on a polyesterurethane as the external layer and a gelatin membrane as the internal layer. The polyesterurethane was synthesized from poly(ε-caprolactone), polyethylene glycol of 1 or 10 kDa as a hydrophilic component or Pluronic F127 as an amphiphilic component and l-lysine ethyl ester diisocyanate as an urethane precursor. Gelatin membrane was obtained by crosslinking with the naturally occurring crosslinker genipin. Three important points were addressed in this study: the physicochemical characterization of the system, the in vitro behaviour and the in vivo performance on a full-thickness wound defect of rat. The polyesterurethane containing polyethylene glycol of 10 kDa presented the optimum properties for the designed application as to be tested in animal experiments. The in vivo results showed good healing of the lesion with the formation of epidermis similar to normal rat skin. These promising results suggest the potential of this system to be used as an affordable wound dressing in the treatment of different dermal lesions.

The effects of ripasudil (K-115), a Rho kinase inhibitor, on activation of human conjunctival fibroblasts

The most common cause of glaucoma surgery failure is scar formation induced by activation of wound-healing responses and resultant fibrosis at the surgical site. We investigated the effects of ripasudil, a Rho kinase inhibitor, on activation of human conjunctival fibroblasts (HConF). HConF were pretreated with different concentrations of ripasudil for 1 h before addition of transforming growth factor (TGF)-β2, followed by incubation for 48 h. TGF-β2-treated fibroblasts exhibited a significant increase in expression of α-smooth muscle actin (α-SMA), a marker of fibroblast-to-myofibroblast differentiation, and this increase was significantly suppressed, in a dose-dependent manner, by pretreatment with ripasudil. Ripasudil pretreatment also significantly attenuated TGF-β2-induced fibronectin production and collagen gel contraction. TGF-β2 increased both the number of viable cells and the number of cells in the G2/M phase of the cell cycle; these effects were attenuated by pretreatment with ripasudil. In addition, we explored the effects of ripasudil on stimulation of HConF by activated macrophages. Human monocytic cell line THP-1 cells were differentiated into M1 or M2 macrophage-like cells, and HConF were treated with conditioned media derived from these macrophages in the presence or absence of ripasudil. Conditioned medium from M2 macrophage-like cells induced a significant increase in α-SMA expression, viable cell numbers, and gel contraction, all of which were significantly suppressed by ripasudil. Thus, overall, ripasudil attenuated activation of human conjunctival fibroblasts. Ripasudil may be of therapeutic utility, preventing excessive scarring after glaucoma filtration surgery.

Epigenetic Modification Prevents Excessive Wound Healing and Scar Formation After Glaucoma Filtration Surgery

PURPOSE

The purpose of this study was to determine the efficacy of suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor (HDACi), in prevention of excessive wound healing and scar formation in a rabbit model of glaucoma filtration surgery (GFS).

METHODS

A rabbit model of GFS was used. Rabbits that underwent GFS received balanced salt solution, or SAHA (50 μM), or mitomycin C (0.02%). Clinical scores of IOP, bleb vascularity, and slit-lamp examination were performed. On postoperative day 14, rabbits were killed and the bleb tissues were collected for evaluation of tissue fibrosis with hematoxylin and eosin, Masson trichrome, α-smooth muscle actin (αSMA), and F-actin staining. Furthermore, SAHA-mediated acetylation of histones in corneal fibroblasts and conjunctiva were determined by Western blot analysis.

RESULTS

Suberoylanilide hydroxamic acid treatment after GFS showed no signs of edema, corneal opacity, endophthalmitis, or cataract formation. Morphometric analysis of SAHA-treated eyes showed higher bleb length (P < 0.001), bleb area (P < 0.05), lower IOP (P < 0.01), and decreased vascularity compared to control. Furthermore, SAHA treatment showed significantly reduced levels of αSMA (P < 0.001), F-actin (P < 0.01), and collagen deposition (P < 0.05) at the sclerotomy site. In addition, SAHA treatment increased the acetylation status of H3 and H4 histones in corneal fibroblasts and conjunctiva.

CONCLUSIONS

This study demonstrates that HDAC inhibition is an attractive pharmacologic target to modulate GFS wound healing, and SAHA, an HDACi, can be a useful adjunct to improve the GFS outcome.

The Effect of Everolimus on Scar Formation in Glaucoma Filtering Surgery in a Rabbit Model

PURPOSE

To investigate the efficiency of everolimus on the prevention of postoperative scar in a rabbit model of glaucoma filtering surgery in comparison with mitomycin-C (MMC).

MATERIALS AND METHODS

Thirty New Zealand albino rabbits were randomly assigned into 3 groups, each including ten rabbits: an everolimus group (Group 1), a MMC group (Group 2), and a sham group (Group 3). A limbal-based trabeculectomy was performed on the right eyes of all the rabbits. For 28 days following surgery, the eyes were evaluated in terms of intraocular pressure (IOP), morphological and biomicroscopic changes, and complications in the bleb. On the 28th day, four eyes randomized from each group were enucleated and histologically and immunohistochemically analyzed. Transforming growth factor-β1 (TGF-β1), metalloproteinase (MMP-2, MMP-9), and proliferative cell nuclear antigen (PCNA) expressions in each group were evaluated. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method was used for apoptosis.

RESULTS

Bleb survival was statistically significantly longer for a period in Group 1 compared to Group 2. When postoperative IOPs of three groups were measured, it was seen that there is significant IOP reduction in all three groups. However, there were increases in the mean IOP values beginning from the 5th day in Group 2 and from the 3rd day in Group 3 while in Group 1 mean IOP values began to increase beginning from 10th day and the mean IOP values in Group 1 remained at a lower level in comparison to the other groups for 28 days (p < 0.05). The expressions of TGF-β1, MMP-2, MMP-9, and PCNA were reduced in Group 1 compared to other groups. TUNEL positive apoptotic cells were significantly increased in Group 1 compared to other groups (p < 0.05).

CONCLUSION

Everolimus appears to suppress the proliferation of fibroblast and thus may provide an effective treatment strategy in glaucoma filtering surgery.

Scleral Flap-Everting Suture for Glaucoma-filtering Surgery

PURPOSE

Most filtering surgery failures develop in the early postoperative period. The possibility to apply an everting suture to lift the flap in the postoperative period and reduce the possibility of an early failure is reported.

METHODS

Surgical technique description.

RESULTS

An everting suture may be applied to the scleral flap in all types of ab externo anterior filtering surgeries. It could allow the surgeon to lift the scleral flap after the removal of the releasable sutures.

CONCLUSIONS

The use of an everting suture would eliminate the need to use procedures for lifting the flap that involve puncturing the conjunctiva and may cause hemorrhages and leakage and promote scarring.

Conjunctival fibrosis following filtering glaucoma surgery

Despite advances in surgical technique and postoperative care, fibrosis remains the major impediment to a marked reduction of intraocular pressure without the need of additional medication (complete success) following filtering glaucoma surgery. Several aspects specific to filtering surgery may contribute to enhanced fibrosis. Changes in conjunctival tissue structure and composition due to preceding treatments as well as alterations in interstitial fluid flow and content due to aqueous humor efflux may act as important drivers of fibrosis. In light of these pathophysiological considerations, current and possible future strategies to control fibrosis following filtering glaucoma surgery are discussed.

Current and Future Techniques in Wound Healing Modulation after Glaucoma Filtering Surgeries

Filtering surgeries are frequently used for controlling intraocular pressure in glaucoma patients. The long-term success of operation is intimately influenced by the process of wound healing at the site of surgery. Indeed, if has not been anticipated and managed accordingly, filtering surgery in high-risk patients could end up in bleb failure. Several strategies have been developed so far to overcome excessive scarring after filtering surgery. The principal step involves meticulous tissue handling and modification of surgical technique, which can minimize the severity of wound healing response at the first place. However, this is usually insufficient, especially in those with high-risk criteria. Thus, several adjuvants have been tried to stifle the exuberant scarring after filtration surgery. Conventionally, corticosteroids and anti-fibrotic agents (including 5-fluorouracil and Mitomycin-C) have been used for over three decades with semi-acceptable outcomes. Blebs and bleb associated complications are catastrophic side effects of anti-fibrotic agents, which occasionally are encountered in a subset of patients. Therefore, research continues to find a safer, yet effective adjuvant for filtering surgery. Recent efforts have primarily focused on selective inhibition of growth factors that promote scarring during wound healing process. Currently, only anti-VEGF agents have gained widespread acceptance to be translated into routine clinical practice. Robust evidence for other agents is still lacking and future confirmative studies are warranted. In this review, we explain the importance of wound healing process during filtering surgery, and describe the conventional as well as potential future adjuvants for filtration surgeries.

Postoperative Changes in Aqueous Monocyte Chemotactic Protein-1 Levels and Bleb Morphology after Trabeculectomy vs. Ex-PRESS Shunt Surgery

Purpose

To evaluate the postoperative changes in blebs and levels of aqueous monocyte chemotactic protein-1 (MCP-1) after trabeculectomy vs. Ex-PRESS tube shunt surgery.

Methods

Rabbits were subjected to trabeculectomy or Ex-PRESS tube shunt surgery and observed for up to 3 months. Intraocular pressure (IOP) was measured using a rebound tonometer. The MCP-1 level was measured by enzyme-linked immunosorbent assay (ELISA). Bleb morphology was evaluated using photos and anterior-segment optical coherence tomography (OCT).

Results

There were no differences in bleb appearance or IOP at any time between the groups. Bleb wall density in the anterior-segment OCT image was significantly lower 1 week after surgery in the Ex-PRESS group than the trabeculectomy group. The MCP-1 level in control eyes was 304.1 ± 45.2 pg/mL. In the trabeculectomy group, the mean aqueous MCP-1 level was 1444.9, 1914.3, 1899.8, 516.4, 398.3, 427.3, 609.5, 1612.7, 386.2, and 167.9 pg/mL at 3, 6, and 12 h, and 1, 2, 5, 7, 14, 30, and 90 days after surgery, respectively. In the Ex-PRESS group, the corresponding values were 1744.0, 1372.0, 932.5, 711.7, 396.1, 487.3, 799.5, 1327.9, 293.6, and 184.0 pg/mL. There were no significant differences in the aqueous MCP-1 level between the groups at any time point.

Conclusion

The postoperative changes were similar in the Ex-PRESS and trabeculectomy groups, except for bleb wall density in the anterior-segment OCT image. The postoperative aqueous MCP-1 level had bimodal peaks in both groups.

Modulation of wound healing in glaucoma surgery

Glaucoma is a neurodegenerative disease and is the second most important cause of irreversible blindness. Filtration surgery remains the most effective therapy to reduce intraocular pressure in glaucoma patients. The main determinant of long-term surgical success is the healing response. Excessive postoperative wound healing with subsequent fibrosis may lead to obstruction of the created channel which frequently results in early surgical failure and consequent progression of visual field loss. Preoperative use of antimitotics, such as mitomycin-C and 5-fluorouracyl, effectively improves surgery outcome. However, the use of these nonspecific antiproliferative agents can be associated with severe side effects. This review provides an overview of the most important efforts that have been made to explore novel, more specific, and safer agents to prevent glaucoma filtration failure and improve surgery outcome.

The Suppression of Wound Healing Response with Sirolimus and Sunitinib Following Experimental Trabeculectomy in a Rabbit Model

PURPOSE

To investigate the effects of sirolimus and sunitinib on wound healing in experimental glaucoma filtering surgery (GFS).

MATERIAL AND METHODS

Thirty-five male New Zealand pigmented rabbits were randomly assigned to five groups, each including seven rabbits: The rabbits in the control group were not operated on and did not receive any treatment. The rabbits in the sham group underwent trabeculectomy and had one drop of saline instilled four times a day for 14 days. The rabbits in the mitomycin-C (MMC) group underwent trabeculectomy, and a sponge soaked in 0.4 mg/mL MMC was applied intraoperatively to the scleral surgical site for three minutes. The rabbits in the sirolimus group underwent trabeculectomy and 30 ng/mL sirolimus-soaked sponge was applied intraoperatively to the scleral surgical site for three minutes. Sunitinib 0.5 mg/mL four drops in a day were applied in the sunitinib group for 14 days after surgery. On day 14 of the experiment, eyes were enucleated and histologically and immunohistochemically analyzed. Statistical analyses of the study were performed with Kruskal-Wallis variance analysis and Mann-Whitney U test.

RESULTS

The mean fibroblast and MNC numbers and the mean immunostaining intensities of transforming growth factor-β (TGF-β), fibroblast growth factor-β (FGF-β) and platelet derived growth factor (PDGF) in the MMC, sirolimus and sunitinib groups were statistically significantly lower than those of the sham group (p < 0.01). The mean fibroblast and MNC numbers and the mean immunostaining intensities of TGF-β, FGF-β and PDGF in the MMC, sirolimus and sunitinib groups were similar (p > 0.05).

CONCLUSIONS

Our study suggests that the applications of sirolimus and sunitinib effectively suppress the subconjunctival scarring after experimental GFS.

[Options for prolonging the hypotensive effect of trabeculectomy]

OBJECTIVE

To assess potential of preoperative therapy with local steroid and non-steroid anti-inflammatory drugs (SAIDs and NSAIDs) for prolonging the hypotensive effect of trabeculectomy.

MATERIAL AND METHODS

A total of 80 patients with primary open-angle glaucoma planed for trabeculectomy were randomized into 4 groups of 20 each: 3 groups that differed in the studied drug (nepafenac, dexamethasone, or their non-fixed combination) and a control group with no preoperative therapy. The patients instilled 1 drop of either drug b.i.d. for 2 weeks before the surgery and were examined each day of the first week and then at weeks 1, 2, 4 and months 3, 6, and 12. The rate of postoperative surgical and medical interventions (needling, needling revision, hypotensive therapy) was used for outcome evaluation.

RESULTS

Postoperative needling was required in 50% of the controls, 35% of the NSAIDs and 30% of the SAIDs patients as well as 20% the combination-therapy patients. Needling revision had to be performed in 10% of patients from the control group and 5% of patients from the NSAIDs group. Patients from the steroid and combination-therapy groups had no need in needling procedure. Further hypotensive therapy was required in 50% of the control group, 35% of the NSAIDs group, 25% of the SAIDs group and 20% of the combination-therapy group. During the first postoperative year complete success of the treatment was achieved in 50% of the controls, 65% of the NSAIDs patients, 75% of the SAIDs patients, and 80% of those under combination therapy. Qualified success during the same period was achieved in 100% of cases.

CONCLUSION

Preoperative local anti-inflammatory therapy helped to increase the one-year complete success rate after trabeculectomy as compared with the controls. The most significant hypotensive effect was noted in the combination-therapy group (80%), less significant--in the steroid and non-steroid monotherapy groups (75% and 65% correspondingly). A negative correlation was noted between the use of nepafenac and dexamethasone and other measures aimed at increasing the hypotensive effect of glaucoma surgery.

A National Survey of Glaucoma Specialists on the Preoperative (Trabeculectomy) Management of the Ocular Surface (.)

BACKGROUND

Preserved anti-glaucoma drops cause ocular surface disease (OSD), which is increasingly being recognized as a likely cause of trabeculectomy failure.

AIM

To determine the routine pre-trabeculectomy management of the ocular surface by glaucoma specialists.

METHODS

A questionnaire consisting of 11 questions was posted to 146 UK glaucoma specialists.

RESULTS

The first-time response rate was 43.8%. Regarding routine pre-operative management, 40.6% of specialists use preservative-free drops, 29.7% commence a drop holiday, and 53% advise lid hygiene. 42.1% prescribe lubricants, 50% prescribe topical steroids, 7.8% topical NSAIDs, and 34.4% systemic tetracyclines. 84.4% of specialists change their routine management if OSD is present. Pre-operative optimization of the ocular surface is viewed "necessary" by 48.4% and "beneficial" by 85.9%.

CONCLUSION

A wide variation exists in the routine pre-operative management of the ocular surface. Research to determine the impact of different pre-operative interventions upon trabeculectomy outcomes is required.