MiR-146a reduces fibrosis after glaucoma filtration surgery in rats.

PURPOSE: To explore the impact of microRNA 146a (miR-146a) and the underlying mechanisms in profibrotic changes following glaucoma filtering surgery (GFS) in rats and stimulation by transforming growth factor (TGF)-ß1 in rat Tenon's capsule fibroblasts. METHODS: Cultured rat Tenon's capsule fibroblasts were treated with TGF-ß1 and analyzed with microarrays for mRNA profiling to validate miR-146a as the target. The Tenon's capsule fibroblasts were then respectively treated with lentivirus-mediated transfection of miR-146a mimic or inhibitor following TGF-ß1 stimulation in vitro, while GFS was performed in rat eyes with respective intraoperative administration of miR-146a, mitomycin C (MMC), or 5-fluorouracil (5-FU) in vivo. Profibrotic genes expression levels (fibronectin, collagen Iα, NF-KB, IL-1ß, TNF-α, SMAD4, and α-smooth muscle actin) were determined through qPCR, Western blotting, immunofluorescence staining and/or histochemical analysis in vitro and in vivo. SMAD4 targeting siRNA was further used to treat the fibroblasts in combination with miR-146a intervention to confirm its role in underlying mechanisms. RESULTS: Upregulation of miR-146a reduced the proliferation rate and profibrotic changes of rat Tenon's capsule fibroblasts induced by TGF-ß1 in vitro, and mitigated subconjunctival fibrosis to extend filtering blebs survival after GFS in vivo, where miR-146a decreased expression levels of NF-KB-SMAD4-related genes, such as fibronectin, collagen Iα, NF-KB, IL-1ß, TNF-α, SMAD4, and α-smooth muscle actin(α-SMA). Additionally, SMAD4 is a key target gene in the process of miR-146a inhibiting fibrosis. CONCLUSIONS: MiR-146a effectively reduced TGF-ß1-induced fibrosis in rat Tenon's capsule fibroblasts in vitro and in vivo, potentially through the NF-KB-SMAD4 signaling pathway. MiR-146a shows promise as a novel therapeutic target for preventing fibrosis and improving the success rate of GFS.

[Pharmacological modulation of wound healing in glaucoma surgery]. / Farmakoterapevticheskie podkhody k upravleniyu reparativnymi protsessami v khirurgii glaukomy.

Despite the well-known effectiveness of pharmacological glaucoma therapy, surgical approach remains one of the main treatment options for some forms and stages of the disease. The long-term success of glaucoma surgery depends on the intensity of local wound healing processes at the surgical site. The most common way to influence healing processes in surgical treatment of glaucoma is the use of antimetabolites. However, given the high risk of serious complications associated with their use, the search for new drugs devoid of these disadvantages continues. The aim of this review is to describe the efficacy and safety of both currently used and upcoming pharmacological ways to influence the wound healing process after glaucoma surgery in order to improve the stability of hypotensive effect.

[Studying the condition of filtering bleb after glaucoma surgery using optical coherence tomography]. / Opticheskaya kogerentnaya tomografiya v issledovanii sostoyaniya fil'tratsionnoi podushki posle antiglaukomnoi khirurgii.

PURPOSE: To compare the optical coherence tomography (OCT) findings on the condition of filtering bleb (FB) in patients with primary open-angle glaucoma (POAG) who used different local therapy before glaucoma surgery. MATERIAL AND METHODS: The study included a total of 82 patients (82 eyes) followed up after glaucoma surgery: 50 patients (50 eyes) who received preservatives-containing drugs before glaucoma surgery; 32 patients (32 eyes) - who were on preservative-free drug treatment before glaucoma surgery. The examinations were carried out 7 days, 1 and 3 months after micro-invasive sinus trabeculectomy. The condition of filtering bleb was studied using the Visante AS-OCT device, as well as with a slit lamp for clinical observation. Corneal-compensated intraocular pressure (IOPcc) was determined by bi-directional pneumatic applanation of the cornea using the Ocular Response Analyzer (ORA). RESULTS: After 3 months post-op, a functioning FB and intraocular pressure below 15.0 mm Hg were observed in 38 eyes out of 50 (76%) in group 1, in 12 eyes (24%) the FB was nonfuncitonal. In Group 2, 25 eyes out of 32 (78%) had functioning FB and intraocular pressure lower than 15.0 mm Hg; in 7 eyes (22%) the FB was nonfuncitonal. Needling was needed 3 months after the operation in 7 eyes out of 32 (22%) in group 2. The need for needling according to OCT findings in patients of group 1 occurred already one week after surgery for 4 eyes out of 50 (8%), after one month - for 14 eyes (28%). CONCLUSION: In patients on pre-operative drug therapy with preservative-containing medications, the process of scarring in the FB is faster. The OCT method allows early detection of the initial signs of scarring, as well as determining the need for needling.

Development of Targeted siRNA Nanocomplexes to Prevent Fibrosis in Experimental Glaucoma Filtration Surgery.

RNAi induced by double-stranded small interfering RNA (siRNA) molecules has attracted great attention as a naturally occurring approach to silence gene expression with high specificity. The myocardin-related transcription factor/serum response factor (MRTF/SRF) pathway is a master regulator of cytoskeletal gene expression and, thus, represents a promising target to prevent fibrosis. A major hurdle to implementing siRNA therapies is the method of delivery, and we have, thus, optimized lipid-peptide-siRNA (LPR) nanoparticles containing MRTF-B siRNAs as a targeted approach to prevent conjunctival fibrosis. We tested 15 LPR nanoparticle formulations with different lipid compositions, surface charges, and targeting or non-targeting peptides in human conjunctival fibroblasts. In vitro, the LPR formulation of the DOTMA/DOPE lipid with the targeting peptide Y (LYR) was the most efficient in MRTF-B gene silencing and non-cytotoxic compared to the non-targeting formulation. In vivo, subconjunctival administration of LYR nanoparticles containing MRTF-B siRNAs doubled bleb survival in a pre-clinical rabbit model of glaucoma filtration surgery. Furthermore, MRTF-B LYR nanoparticles reduced the MRTF-B mRNA by 29.6% in rabbit conjunctival tissues, which led to significantly decreased conjunctival scarring with no adverse side effects. LYR-mediated delivery of siRNA shows promising results to increase bleb survival and to prevent conjunctival fibrosis after glaucoma filtration surgery.

The treatment of a hypertrophic bleb after XEN gel implantation with the "Drainage Channel with sutures" method: a case report.

BACKGROUND: The placement of a XEN gel stent is an ab-interno, minimally invasive glaucoma surgery which provides a subconjunctival drainage pathway and decreases intraocular pressure (IOP). CASE PRESENTATION: A 75-year-old male patient who had undergone XEN45 gel implantation after phacoemulsification and intraocular lens implantation appealed to the clinic. A filtration bleb was seen that extended through the nasal 180 degrees of the eye which caused ectropion of the lower eyelid. The value of the IOP was 12 mm Hg (mmHg). By the "Drainage Channel with Sutures" method this complication was effectively treated. As with every new method, there is a lack of knowledge about long-term outcomes in terms of effectiveness, technique and complications. CONCLUSION: The "Drainage Channel with Sutures" method has not been described in the literature yet. By this minimal invasive method, hypertrophic bleb complication of XEN gel implant has been successfully treated.

Prospective study on a novel treatment for leaking cystic bleb: Efficacy and safety of collagen crosslinking.

IMPORTANCE: Management of cystic bleb leak is difficult. It would be essential to look for a method to strengthen the original pathological conjunctiva and reverse bleb leak. BACKGROUND: To evaluate the long-term efficacy and safety of collagen crosslinking in patients with leaking cystic bleb. DESIGN: Prospective interventional case series at a university-based hospital. PARTICIPANTS: Twelve eyes in 12 subjects with late-onset bleb leak from cystic bleb, without indications for prompt surgical interventions were included. METHODS: The subjects underwent crosslinking with 0.1% riboflavin application to bleb surface, followed by ultraviolet irradiation for 30 minutes. The subjects were followed up at baseline and at 1 week, 1 month, 3 months, 6 months post-treatment and then every 6 months afterwards. MAIN OUTCOME MEASURES: Interval from treatment to cessation of bleb leak, recurrence rate of bleb leak and side effects of treatment. RESULTS: The mean follow-up after crosslinking was 29.33 ± 12.45 months. Bleb leak subsided in 11 (92%) of 12 patients after a single session of crosslinking, after 1 to 8 weeks (median 3 weeks). Time to leak cessation was significantly correlated with the number of prior glaucoma interventions (R = .71, P = .014). Bleb wall at 3 months was significantly thicker than at baseline (0.70 ± 0.67 vs 0.81 ± 0.62 mm, P = .008). None of the patients experienced any complications. CONCLUSIONS AND RELEVANCE: Crosslinking achieves resolution of cystic bleb leak which lasts for at least 12 months, without the need of subsequent surgical interventions. Crosslinking is a simple, non-invasive treatment for bleb leak. It aims to restore the integrity of conjunctiva.

Descemet's Membrane Dehiscence Resulting From Misdirected Viscoelastic During Anterior Chamber Reformation.

We report a case of Descemet's membrane detachment after inadvertent intrastromal injection of hyaluronic acid. Surgical removal was attempted with minimal but slow improvement. Near-complete resolution occurred with subsequent conservative management within 6 weeks.

VISCOELASTIC ASSISTED DRAINAGE OF SUPRACHOROIDAL HEMORRHAGE ASSOCIATED WITH SETON DEVICE IN GLAUCOMA FILTERING SURGERY.

PURPOSE: The purpose of this article is to describe a novel surgical technique for the management of large suprachoroidal hemorrhages associated with the insertion of glaucoma seton devices. METHODS: In this interventional case series, the authors describe six eyes of six patients who had management of suprachoroidal hemorrhage with pars plana choroidal drainage along with simultaneous insertion of viscoelastic into the posterior segment. All patients had a median of 8-month postoperative follow-up. RESULTS: Five of the 6 patients had useful final vision ranging from 20/40 to 20/200. In all cases, the postoperative intraocular pressures did not increase beyond 28 mmHg and responded to aqueous humor suppressants. CONCLUSION: As suprachoroidal hemorrhage can be a devastating complication of glaucoma surgery, the authors report a relatively straightforward surgical technique that can restore ambulatory vision in a high proportion of patients.

[Ahmed valve in glaucoma surgery]. / Klapan Akhmeda v khirurgii glaukomy.

This is a review on Ahmed valve application in glaucoma surgery. It contains, in particular, data on the Ahmed valve efficiency, results of experimental and histological studies of filtering bleb encapsulation, examines the use of antimetabolites and anti-VEGF agents, and discusses implantation techniques. The current appraisal of antimetabolites delivery systems integrated into the Ahmed valve is presented. Various complications encountered in practice and preventive measures are also covered.

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.

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)-ß2, followed by incubation for 48 h. TGF-ß2-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-ß2-induced fibronectin production and collagen gel contraction. TGF-ß2 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.

Difference in glaucoma progression between the first and second eye after consecutive bilateral glaucoma surgery in patients with bilateral uveitic glaucoma.

PURPOSE: To determine whether the second eyes (SE) of patients with bilateral uveitic glaucoma undergoing filtration surgery have more glaucomatous progression in terms of visual acuity, visual field (VF) and optic nerve changes compared to the first eyes (FE). METHODS: This retrospective study analysed data of 60 eyes from 30 patients with bilateral uveitic glaucoma who had undergone glaucoma surgery in both eyes on separate occasions. Humphrey VF progression was assessed using the Progressor software. RESULTS: The pre-operative IOP between the FE (43.1 ± 7.7 mmHg) and SE (40 ± 8.7 mmHg) was not statistically significant (p = 0.15). IOP reduction was greater in the FE (64 %) than SE (59.7 %) post-operatively, but the mean IOP at the final visit in the FE (12.3 ± 3.9 mmHg) and SE (14.5 ± 7 mmHg) was not statistically different (p = 0.2). There was no significant change in mean logMAR readings pre and post-operatively (0.45 ± 0.6 vs 0.37 ± 0.6, p = 0.4) or between the FE and SE. The number of SE with CDR > 0.7 increased by 23 % compared to the FE. From 23 available VFs, five SE (21.7 %) progressed at a median of five locations (range 1-11 points) with a mean local slope reduction of 1.74 ± 0.45 dB/year (range -2.39 to -1.26), whereas only one FE progressed. However, there was no significant difference between mean global rate of progression between the FE (-0.9 ± 1.6 dB/year) and SE (-0.76 ± 2.1 dB/year, p = 0.17) in the Humphrey VF. CONCLUSION: In eyes with bilateral uveitic glaucoma requiring glaucoma surgery, the SEs had more progressed points on VF and glaucomatous disc progression compared to FEs at the final visit.

Distinctive and pervasive alterations in aqueous humor protein composition following different types of glaucoma surgery.

PURPOSE: To investigate whether specific glaucoma surgeries are associated with differences in aqueous humor protein concentrations compared to eyes without filters. METHODS: In this cross-sectional study, aqueous humor samples were prospectively collected from control subjects who underwent routine cataract surgery (n=14) and from patients who had different glaucoma filters: Baerveldt aqueous shunt (n=6), Ahmed aqueous shunt (n=6), trabeculectomy (n=5), and Ex-Press trabeculectomy (n=3). Total protein concentrations were determined with Bradford assay. Tryptic digests were analyzed with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Proteins were identified with high confidence using stringent criteria and were quantitatively compared with a label-free platform. Relative protein quantities were compared across groups with ANOVA. Post hoc pair-wise comparisons were adjusted for multiple comparisons. RESULTS: Compared to the control eyes, the aqueous humor protein concentration was increased approximately tenfold in the Ahmed and Baerveldt eyes and fivefold in the trabeculectomy and Ex-Press eyes. Overall, 718 unique proteins, splice variants, or isoforms were identified. No differences in the protein concentrations were detected between the Baerveldt and Ahmed groups. Likewise, the trabeculectomy and Ex-Press groups were remarkably similar. Therefore, the aqueous shunt groups were pooled, and the trabeculectomy groups were pooled for a three-way comparison with the controls. More than 500 proteins differed significantly in relative abundance (ANOVA p<0.01) among the control, aqueous shunt, and trabeculectomy groups. Functional analyses suggested these alterations in relative protein abundance affected dozens of signaling pathways. CONCLUSIONS: Different glaucoma surgical procedures were associated with marked increases in the aqueous humor protein concentration and distinctive changes in the relative abundance of numerous proteins involved in multiple signaling pathways.

Inhibition by a retinoic acid receptor γ agonist of extracellular matrix remodeling mediated by human Tenon fibroblasts.

PURPOSE: Scar formation is most frequently responsible for the failure of glaucoma filtration surgery. Retinoic acids are vitamin A derivatives that play diverse roles in development, immunity, and tissue repair. The effects of the retinoic acid receptor (RAR) γ agonist R667 on the contractility of human Tenon fibroblasts (HTFs) cultured in a three-dimensional collagen gel as well as on intraocular pressure (IOP) in a rat model of glaucoma filtration surgery were investigated. METHODS: HTFs were cultured in a type I collagen gel, the contraction of which was evaluated by measurement of the gel diameter. The release of matrix metalloproteinases (MMPs) into culture supernatants was assessed with immunoblot analysis and gelatin zymography. Phosphorylation of focal adhesion kinase (FAK) was examined with immunoblot analysis, and production of fibronectin and type I collagen was measured with immunoassays. RESULTS: R667 inhibited transforming growth factor-ß1 (TGF-ß1)-induced collagen gel contraction mediated by HTFs in a concentration- and time-dependent manner, whereas an RARα agonist inhibited this process to a lesser extent and an RARß agonist had no effect. TGF-ß1-induced MMP-1 and MMP-3 release, FAK phosphorylation, and fibronectin and type I collagen production in HTFs were also attenuated by R667. Furthermore, R667 lowered IOP in rats after glaucoma filtration surgery. CONCLUSIONS: R667 inhibited TGF-ß1-induced contraction and extracellular matrix synthesis in HTFs. Such effects might have contributed to the lowering of IOP by R667 in a rat model of glaucoma filtration surgery. RARγ agonists might thus prove effective for inhibition of scar formation after such surgery.

Canaloplasty versus non-penetrating deep sclerectomy - a prospective, randomised study of the safety and efficacy of combined cataract and glaucoma surgery; 12-month follow-up.

PURPOSE: To compare outcomes of phaco-canaloplasty (PC) and phaco-non-penetrating deep sclerectomy (PDS) with a viscoelastic compound. METHODS: This study included 29 eyes after PC and 30 after PDS. Indications were uncontrolled primary open-angle glaucoma (POAG) and a cataract. Corrected distance visual acuity (CDVA), intraocular pressure (IOP), and number of medications were evaluated. Follow-up examinations were performed on days 1 and 7, and after 1, 3, 6, and 12 months. Complete and qualified success was an IOP ≤ 18 mmHg. RESULTS: At the 12-month follow-up, mean IOP decreased in the PC group from 19.0 ±6.9 mmHg to 12.6 ±2.7 mmHg, and in the PDS group, from 19.1 ±5.8 mmHg to 14.3 ±3.5 mmHg (P < 0.05). Both groups preoperatively and at 12 months showed no significant differences in IOP (P > 0.05). There was no statistically significant difference between the number of medications used (P > 0.05). Complete and qualified success rates for both groups were 79.0 % and 76.9 % (P = 0.701). The most frequent postoperative PC complication was hyphema (58.0 %); for PDS, bleb fibrosis was most frequent (26.7 %). No PC patients required postoperative management. PDS patients required postoperative interventions 58.7 % of the time, including a 5-fluorouracil (5-FU) injection (58.7 %), suture lysis (48.3 %), and needling (27.6 %). CONCLUSIONS: Both PC and PDS lead to an effective decrease in IOP on a short-term follow-up basis and demonstrate similar efficacy and safety profiles. PDS patients required additional procedures including 5-FU injections, suture lysis, or needling. PC patients required no additional procedures.

Pathobiology of wound healing after glaucoma filtration surgery.

Conjunctival and subconjunctival fibrogenesis and inflammation are sight compromising side effects that can occur subsequent to glaucoma filtration surgery. Despite initial declines in intraocular pressure resulting from increasing aqueous outflow, one of the activated responses includes marshalling of proinflammatory and pro-fibrogenic cytokine mediator entrance into the aqueous through a sclerostomy window and their release by local cells, as well as infiltrating activated immune cells. These changes induce dysregulated inflammation, edema and extracellular matrix remodeling, which occlude outflow facility. A number of therapeutic approaches are being taken to offset declines in outflow facility since the current procedure of inhibiting fibrosis with either mitomycin C (MMC) or 5-fluorouracil (5-FU) injection is nonselective. One of them entails developing a new strategy for reducing fibrosis induced by wound healing responses including myofibroblast transdifferentiation and extracellular matrix remodeling in tissue surrounding surgically created shunts. The success of this endeavor is predicated on having a good understanding of conjunctival wound healing pathobiology. In this review, we discuss the roles of inappropriately activated growth factor and cytokine receptor linked signaling cascades inducing conjunctival fibrosis/scarring during post-glaucoma surgery wound healing. Such insight may identify drug targets for blocking fibrogenic signaling and excessive fibrosis which reduces rises in outflow facility resulting from glaucoma filtration surgery.

Effects of bevacizumab loaded PEG-PCL-PEG hydrogel intracameral application on intraocular pressure after glaucoma filtration surgery.

PEG-PCL-PEG (PECE) hydrogel for intracameral injection as a sustained delivery system can get a stable release of the medication and achieve an effective local concentration. The injectable PECE hydrogel is thermosensitive nano-material which is flowing sol at low temperature and can shift to nonflowing gel at body temperature. This study evaluated the intracameral injection of bevacizumab combined with a PECE hydrogel drug release system on postoperative scarring and bleb survival after experimental glaucoma filtration surgery. The best result was achieved in the bevacizumab loaded PECE hydrogels group, which presented the lowest IOP values after surgery. And the blebs were significantly more persistent in this group. Histology, Massion trichrome staining and immunohistochemistry further demonstrated that glaucoma filtration surgery in combination with bevacizumab loaded PECE hydrogel resulted in good bleb survival due to scar formation inhibition. In conclusions, this study demonstrated that bevacizumab-loaded PECE hydrogel for intracameral injection as a sustained delivery system provide a great opportunity to increase the therapeutic efficacy of glaucoma filtration surgery.

Hemorrhagic descemet membrane detachment after classic canaloplasty.

PURPOSE: Canaloplasty is a safe and effective alternative in glaucoma surgery, avoiding the risk for hypotony and bleb-related complications. Two cases of hemorrhagic Descemet membrane detachment (DMD) after canaloplasty are reported in patients who did not have previous surgery. RESULTS: Two patients with primary open-angle glaucoma underwent canaloplasty because of medically uncontrolled intraocular pressure (IOP). Canaloplasty was performed using a flexible microcatheter, viscoelastic material and a tensioning suture. The day after surgery, hemorrhagic DMD was observed in the inferior quadrants in both patients on slit-lamp biomicroscopy. THERAPY: For the size and location (occlusion of the visual axis), aspiration of blood and descemetopexy with air tamponade were performed promptly. In both cases, a small translucent scar remained. CONCLUSIONS: Circumferential cannulation and viscodilation of the Schlemm canal increases the risk for DMD, which may be aggravated by blood reflux resulting from the tensioning suture and low postoperative IOP. Surgeons should be aware of this specific and potentially sight-threatening complication in classic canaloplasty. Immediate intervention is recommended for good visual prognosis.