Pharmacological Approaches to Modulate the Scarring Process after Glaucoma Surgery

Plasma rich in growth factors (PRGF) technology as adjuvant to Ab Externo trabeculectomy

PURPOSE

Plasma rich in growth factors (PRGF) technology creates blood-derived products with growth factors that promote wound healing and regeneration. The goal of this study was to assess the potential role of PRGF products as wound modulators in trabeculectomy. Our premise is that due to PRGF's regenerative and antifibrotic properties, its use in trabeculectomy may produce a more physiological bleb, without altering IOP reduction.

METHODS

A retrospective, longitudinal study was conducted in a Hospital in Portugal. Patients with eyes with open angle glaucoma were included. Trabeculectomy was performed on all patients using PRGF membrane (mPRGF) under the conjunctiva, as adjuvant. Data regarding patients' demographics and number of medications used, was collected. Intraocular pressure (IOP) before surgery, 8 days, 1 month, 3 month, 6 month, 9 month and 1 year after surgery was recorded. Bleb morphology was classified according to Moorfields Bleb Grading System 6 months after surgery.

RESULTS

Nine eyes of 9 patients were enrolled. Mean age was 71 ± 5.1 years old. Six were male. Mean IOP decreased from 24.0 ± 8.8 mmHg pre-surgery to 12.9 ± 2.6 mmHg at one year follow-up. The number of hypotensive drugs (mean ± SD) was 4.3 ± 0.9 preoperatively and 0.8 ± 1.1 at 1-year. Complete success was defined as IOP equal to or less than 21 mm Hg without ocular hypotensive medications and qualified success as IOP equal to or less than 21 mm Hg with medications. Complete success was 66.7% and qualified success was 100% at 1 year follow-up.

CONCLUSION

In our study, trabeculectomy with mPRGF demonstrated both safety and efficacy. Low values of bleb height (1.6 ± 0.8) were recorded. mPRGF could improve wound healing and produce a more well-tolerated, favourable bleb, avoiding antimetabolite complications.

Inhibition of the rapamycin-insensitive mTORC1 /4E-BP1 axis attenuates TGF-β1-induced fibrotic response in human Tenon's fibroblasts

Subconjunctival fibrosis is the major cause of failure in both conventional and modern minimally invasive glaucoma surgeries (MIGSs) with subconjunctival filtration. The search for safe and effective anti-fibrotic agents is critical for improving long-term surgical outcomes. In this study, we investigated the effect of inhibiting the rapamycin-insensitive mTORC1/4E-BP1 axis on the transforming growth factor-beta 1(TGF-β1)-induced fibrotic responses in human Tenon's fibroblasts (HTFs), as well as in a rat model of glaucoma filtration surgery (GFS). Primary cultured HTFs were treated with 3 ng/mL TGF-β1 for 24 h, followed by treatment with 10 μM CZ415 for additional 24 h. Rapamycin (10 μM) was utilized as a control for mTORC1/4E-BP1 signaling insensitivity. The expression levels of fibrosis-associated molecules were measured using quantitative real-time PCR, Western blotting, and immunofluorescence analysis. Cell migration was assessed through the scratch wound assay. Additionally, a rat model of GFS was employed to evaluate the anti-fibrotic effect of CZ415 in vivo. Our findings indicated that both rapamycin and CZ415 treatment significantly reduced the TGF-β1-induced cell proliferation, migration, and the expression of pro-fibrotic factors in HTFs. CZ415 also more effectively inhibited TGF-β1-mediated collagen synthesis in HTFs compared to rapamycin. Activation of mTORC1/4E-BP signaling following TGF-β1 exposure was highly suppressed by CZ415 but was only modestly inhibited by rapamycin. Furthermore, CZ415 was found to decrease subconjunctival collagen deposition in rats post GFS. Our results suggest that rapamycin-insensitive mTORC1/4E-BP1 signaling plays a critical role in TGF-β1-driven collagen synthesis in HTFs. This study demonstrated that inhibition of the mTORC1/4E-BP1 axis offers superior anti-fibrotic efficacy compared to rapamycin and represents a promising target for improving the success rate of both traditional and modern GFSs.

The Effect of Trabecular Aspiration on Intraocular Pressure, Medication and the Need for Further Glaucoma Surgery in Eyes with Pseudoexfoliation Glaucoma

PURPOSE

To investigate whether trabecular aspiration (TA) has an effective medium-term intraocular pressure (IOP)-lowering and medication-saving effect in patients with pseudoexfoliation glaucoma (PEG). In addition, a subgroup analysis of patients with or without a previous trabeculectomy was performed.

METHODS

Records of 290 consecutive eyes with PEG that underwent TA between 2006 and 2012 at the Department of Ophthalmology, Mainz, Germany, were retrospectively analyzed with a follow-up period of 3 years. The main outcomes were IOP and the need for further medical treatment.

RESULTS

Of the 290 eyes with PEG that received TA, 167 eyes from 127 patients met the inclusion criteria. Among these eyes, 128 received TA and cataract surgery (Phaco-TA) without having had a trabeculectomy (group I) before, 29 had Phaco-TA after a previous trabeculectomy (group II) and 10 underwent stand-alone TA after a previous trabeculectomy (group III). In the whole cohort, the median IOP decreased immediately after TA and remained significantly lower compared to the baseline throughout the period of 36 months. Likewise, the median number of antiglaucoma drugs was reduced over the whole period. At the same time, in group I, the median IOP and the number of antiglaucoma drugs were reduced over 36 months. In contrast, in the post-trabeculectomy groups (group II and III), the median IOP and the number of antiglaucoma drugs could not be reduced. While most of the patients that received Phaco-TA with or without a previous trabeculectomy (group I and II) did not require further surgical intervention during the follow-up period, almost all patients receiving stand-alone TA after a previous trabeculectomy (group III) needed surgical therapy, most of them between the second and the third year following TA.

CONCLUSIONS

Phaco-TA has an effective medium-term pressure-lowering and medication-saving effect, especially in patients without a previous trabeculectomy. In trabeculectomized eyes, the effect of TA is limited but still large enough to delay more invasive surgical interventions in some patients.

Wound Modulations in Glaucoma Surgery: A Systematic Review

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

Pharmacological Stimulation of Soluble Guanylate Cyclase Counteracts the Profibrotic Activation of Human Conjunctival Fibroblasts

Conjunctival fibrosis is a serious clinical concern implicated in a wide spectrum of eye diseases, including outcomes of surgery for pterygium and glaucoma. It is mainly driven by chronic inflammation that stimulates conjunctival fibroblasts to differentiate into myofibroblasts over time, leading to abnormal wound healing and scar formation. Soluble guanylate cyclase (sGC) stimulation was found to suppress transforming growth factor β (TGFβ)-induced myofibroblastic differentiation in various stromal cells such as skin and pulmonary fibroblasts, as well as corneal keratocytes. Here, we evaluated the in vitro effects of stimulation of the sGC enzyme with the cell-permeable pyrazolopyridinylpyrimidine compound BAY 41-2272 in modulating the TGFβ1-mediated profibrotic activation of human conjunctival fibroblasts. Cells were pretreated with the sGC stimulator before challenging with recombinant human TGFβ1, and subsequently assayed for viability, proliferation, migration, invasiveness, myofibroblast marker expression, and contractile properties. Stimulation of sGC significantly counteracted TGFβ1-induced cell proliferation, migration, invasiveness, and acquisition of a myofibroblast-like phenotype, as shown by a significant downregulation of FAP, ACTA2, COL1A1, COL1A2, FN1, MMP2, TIMP1, and TIMP2 mRNA levels, as well as by a significant reduction in α-smooth muscle actin, N-cadherin, COL1A1, and FN-EDA protein expression. In addition, pretreatment with the sGC stimulator was capable of significantly dampening TGFβ1-induced acquisition of a contractile phenotype by conjunctival fibroblasts, as well as phosphorylation of Smad3 and release of the proinflammatory cytokines IL-1β and IL-6. Taken together, our findings are the first to demonstrate the effectiveness of pharmacological sGC stimulation in counteracting conjunctival fibroblast-to-myofibroblast transition, thus providing a promising scientific background to further explore the feasibility of sGC stimulators as potential new adjuvant therapeutic compounds to treat conjunctival fibrotic conditions.

Randomised clinical trial for morphological changes of trabecular meshwork between Kahook dual-blade goniotomy and ab interno trabeculotomy with a microhook

We demonstrated whether the difference of trabecular meshwork remodeling occur depending on the incisional cross-sectional area by comparing Kahook dual-blade goniotomy (KDB) and ab interno trabeculotomy with a microhook. Phakic eyes with primary open-angle or exfoliative glaucoma were randomised into a KDB or a microhook group. The primary outcome was an incisional cross-sectional area quantified by anterior segment optical coherence tomography. In subgroup analysis, the number of patients with the unidentifiable incisional area was compared between the groups. Secondary outcomes were the rate of intraocular pressure changes, the laser flare metre values, corneal endothelial cell densities, the number of glaucoma medications, the usage rate per glaucoma medication type and postoperative complications between the two groups. A total of 29 eyes in 29 patients in the KDB and microhook group were included respectively, with an overall mean age of 72.6 ± 8.1 years. The incisional cross-sectional area of the KDB group was significantly larger at 1 week and at 1, 6 and 12 months (p < 0.01) postoperatively. The number of patients with the nonidentified incisional area was higher at 1, 6 and 12 months postoperatively (p ≤ 0.03) in the microhook group. The flare values in the KDB group were higher than those in the microhook group at 12 months postoperatively (p = 0.02). No significant differences were observed in other secondary outcomes. Incisional cross-sectional area remains larger in eyes treated with KDB goniotomy than in those treated with ab interno trabeculotomy with the microhook, whereas KDB goniotomy did not have an advantage in controlling intraocular pressure postoperatively.Trial registration: UMIN000041290 (UMIN, University Hospital Medical Information Network Clinical Trials Registry of Japan; date of access and registration, 03/08/2020).

Immunomodulatory and Antioxidant Drugs in Glaucoma Treatment

Glaucoma, a group of diseases characterized by progressive retinal ganglion cell loss, cupping of the optic disc, and a typical pattern of visual field defects, is a leading cause of severe visual impairment and blindness worldwide. Elevated intraocular pressure (IOP) is the leading risk factor for glaucoma development. However, glaucoma can also develop at normal pressure levels. An increased susceptibility of retinal ganglion cells to IOP, systemic vascular dysregulation, endothelial dysfunction, and autoimmune imbalances have been suggested as playing a role in the pathophysiology of normal-tension glaucoma. Since inflammation and oxidative stress play a role in all forms of glaucoma, the goal of this review article is to present an overview of the inflammatory and pro-oxidant mechanisms in the pathophysiology of glaucoma and to discuss immunomodulatory and antioxidant treatment approaches.