Uses and complications of mitomycin C in ophthalmology

Efficacy and Safety of the Subtenon Injection of 0.01% Mitomycin C-augmented Trabeculectomy

Background Trabeculectomy, with the application of mitomycin C (MMC), has been the gold standard glaucoma-filtering surgery. The conventional method of applying MMC using soaked sponges does not ensure a controlled amount of delivery of MMC, and incidences of blebitis are reported to be associated with leftover sponges. This study aims to assess the safety and efficacy of a low dose (0.1 mg/ml) of MMC administered through subtenon injection during trabeculectomy combined with cataract extraction, addressing existing research gaps. Methods It is a prospective interventional study on patients who underwent trabeculectomy with a subtenon injection of 0.1 mg/ml of MMC combined with cataract extraction and were followed up over six months. Efficacy was determined in terms of intraocular pressure (IOP) reduction; bleb architecture was graded using the Indiana Bleb Appearance Grading System (IBAGS) and success rate, and safety was commented upon in terms of complications. Results Thirty patients were enrolled, with the majority having primary open-angle glaucoma (63.33%), while 36.67% had primary angle-closure glaucoma. Baseline IOP was 31.40(±10.38) mmHg. It significantly reduced to 14.60(±3.75) mmHg on the first postoperative day, decreasing to 9.55(±1.57) mmHg by the sixth postoperative month (p=0.001). The percentage reduction in IOP was substantial, 69.57%, by the sixth postoperative visit. Bleb morphology assessment using IBAGS revealed significant improvements in bleb height and extent and a reduction in vascularity over the six-month follow-up (p=0.001), and no eyes had bleb encapsulation. Out of the total patients, 93.33% achieved controlled IOP without anti-glaucoma medications, while 6.67% required one medication for IOP control. Complications were minimal, with transient corneal edema in six patients and manageable postoperative hypotony in one case. Conclusion A subtenon injection of MMC during trabeculectomy effectively reduces IOP and promotes favorable bleb architecture, offering an effective and safer alternative to the conventional approach.

Effect of vincristine on intraocular pressure and tear fluid oxidative stress biomarkers in canine transmissible venereal tumor

BACKGROUND

The ocular side effects of cancer chemotherapeutic drugs are relatively uncommon. Nonetheless, the ocular system has a potentially high sensitivity to toxic substances. This study proposed a framework to assess the effect of vincristine chemotherapy on intraocular pressure, tear protein, and oxidative stress in canines with transmissible venereal tumor (TVT).

METHODS

The study group comprised 10 dogs with TVT, whose diagnosis was based on cytology, and all dogs were treated with vincristine for 4 weeks. Each animal was given a complete ophthalmic examination, followed by a standard Schirmer tear test. Before and 20 min after administering vincristine, intraocular pressure (IOP) was measured in the eyes with a noncontact tonometer. At any of the times mentioned, tear samples were collected using the Schirmer test procedure and were subjected to protein analysis-oxidative stress index (OSI), total antioxidant capacity (TAC), total oxidant status (TOS), nitric oxide (NO), and malondialdehyde (MDA) were determined, and standard statistical analysis was applied.

RESULTS

No significant differences were found in protein in tears, but mean Pre and Postinjection IOP revealed a significant decrease in the eyes each week. Also, results indicated significant differences in oxidative stress markers: increased OSI, NO, and MDA, and reduced TAC.

CONCLUSION

The importance of an increase in oxidative stress levels in the tears of vincristine-treated patients should be taken seriously, as it appears to play a role in the pathogenesis of eye disease. Therefore, during the treatment weeks prior to prescribing vincristine, eye diseases should be evaluated and considered.

Pirfenidone: A Promising Drug in Ocular Therapeutics

Pirfenidone, initially indicated for lung fibrosis, has gone beyond its original purpose, and shown promise in eye care. This detailed review tracks its evolution from lung treatment to aiding eye healing as evidenced by published literature. Pirfenidone's multifaceted attributes extend to mitigating corneal fibrosis, inflammation, and trauma. Through rigorous investigations, its efficacy emerges in diabetic retinopathy, macular degeneration, and postoperative glaucoma interventions. As an unheralded protagonist, pirfenidone reshapes ocular care paradigms, inviting renewed research opportunities.

Interleukin 12 in the Acute Phase of the Immune Response after Excimer Laser Treatment

BACKGROUND AND OBJECTIVES

The aim of the research was to investigate the differences in the concentrations of IL-12, IL-4, IL-10, and IFN-γ in tears after LASIK and PRK procedures.

MATERIALS AND METHODS

The study included 68 myopic eyes up to -3.0 D refractive spherical equivalent, divided into two groups: Group 1 LASIK (n = 31) and Group 2 PRK (n = 37). Three tear samples were taken from each eye: immediately before the procedure (t₀), 1 h after the procedure (t₁), and 24 h after the procedure (t₂). The concentrations of IL-12p70, IL-4, IL-10, and IFN-γ in the tear samples were determined by flow cytometry. Participants were not taking anti-inflammatory therapy 24 h after the procedure.

RESULTS

IL-4 levels 1 h after treatment did not differ between LASIK and PRK (p = 0.990), while 24 h after PRK there was a significant decrease in IL-4 levels (p < 0.05), but not after LASIK (p = 0.476). In both the LASIK (p < 0.05) and PRK (p < 0.05) groups, there is an increase in IL-10 concentrations 1 h after treatment, which persists 24 h after LASIK (p < 0.05) but not after PRK (p = 0.081). There is an increase in IL-12p70 concentration 1 h after treatment in both the LASIK (p < 0.001) and PRK groups (p < 0.001). There is also an increase in IL-12p70 concentration 24 h after PRK (p < 0.005), but not after LASIK (p = 0.775).

CONCLUSIONS

IL-4 concentration shows a significantly higher value in the LASIK group than in the PRK group after 24 h. IL-10 and IL-12p70 levels increase one hour after surgery in both groups. After 24 h, the IL-10 levels remain elevated in the LASIK group, and the IL-12p70 levels remain elevated in the PRK group. Thus, LASIK and PRK procedures show different inflammatory dynamics.

Medical treatment for ocular surface squamous neoplasia

Ocular surface squamous neoplasia (OSSN) is the most common non-melanocytic tumour of the ocular surface. Surgical excision with wide margins using the "no-touch" method was originally the most popular treatment for OSSN. However, in the past two decades, the use of topical medications for OSSN treatment has gained a reputation amongst ophthalmologists for being an effective alternative to surgical excision. Furthermore, technological advancements, such as those seen in high-resolution optical coherence tomography (HR-OCT) for the anterior segment, have facilitated the diagnosis and monitoring of OSSN. When selecting a topical agent, interferon alpha-2b (IFNα-2b) and 5-fluorouracil (5-FU) are two of the gentlest medications used for OSSN and are often considered first line therapies due to their high-resolution rates and mild side effect profiles. Mitomycin C (MMC), on the other hand, has a highly toxic profile; therefore, while effective, in our hands it is considered as a second-line treatment for OSSN if the other modalities fail. In addition, newer and less studied agents, such as immune checkpoint inhibitors, retinoic acid, aloe vera, and anti-vascular endothelial growth factor have anti-neoplastic properties and have shown potential for the treatment of OSSN. We enclose an updated literature review of medical treatments for OSSN.

Conjunctival and Limbal Conjunctival Autograft vs. Amniotic Membrane Graft in Primary Pterygium Surgery: A 30-Year Comprehensive Review

INTRODUCTION

The purpose of this study is to compare the "real-life" effectiveness of amniotic membrane graft (AMG) and conjunctival (CAT) or limbal conjunctival (LCA) autograft in the management of primary pterygium.

METHODS

Human-based studies on primary pterygium surgery that were published between 1993 and 2022 with at least 3 months of follow-up were identified, and only those that were retrospective were included. The global recurrence rate of pterygium was assessed for each surgical technique separately. Specific recurrence rates taking into consideration the fixation technique (glue versus sutures) were also measured.

RESULTS

35 real-life retrospective subgroups comprising a total of 3747 eyes were included in the final review. The mean global recurrence rates for CAT, LCA and AMG were 7.61%, 5.50% and 9.0%, respectively. Recurrences were less common for patients who received fibrin glue (5.92%, 2.56% and 3.60%) than for those who received sutures (8.99%, 6.03% and 23.0%) for the three groups, respectively. Surgical techniques combining CAT or LCA with AMG yielded an even lower global recurrence rate (1.83%).

CONCLUSION

AMG seems like a reasonable option that could be considered in primary pterygium surgery, especially when glued to the underlying sclera. Combining AMG with other treatment modalities such as CAT or LCA seems to offer an interesting alternative in terms of recurrence.

Hypertrophic Scars and Keloids: Advances in Treatment and Review of Established Therapies

Hypertrophic scars and keloids can have significant detrimental effects on patients both psychosocially and functionally. A careful identification of patient risk factors and a comprehensive management plan are necessary to optimize outcomes. Patients with a history of dystrophic scarring should avoid unnecessary procedures and enhance the wound-healing process using various preventive strategies. As there is no single, fully efficacious treatment modality, prevention remains the best approach in reducing aberrant scar formation. When prevention therapies fail, keloids have been shown to be respond to a variety of therapies including topical and injectable corticosteroids, 5-fluorouracil, radiotherapy, lasers, and surgical excision, all with varying efficacies. As such, management should be tailored to the individual patient's risk factors with the use of combination therapies to reduce recurrence rates. Still, keloid and hypertrophic scar therapies are widely diverse with novel treatment modalities providing alternatives for recurring lesions. Laser-assisted drug delivery, skin priming, and novel topical therapies may provide alternative options for the management of hypertrophic scars and keloids.

Inadvertent filtering bleb due to extracapsular cataract extraction wound reopening after mitomycin C use: a case report

BACKGROUND

 Mitomycin C has been used adjunctively in various procedures, including pterygium excision. Delayed wound healing, the long-term complication of mitomycin C, can occur several years later and may rarely cause a subsequent inadvertent filtering bleb. However, conjunctival bleb formation from the reopening of an adjacent surgical wound after mitomycin C use has not been reported.

CASE PRESENTATION

A 91-year-old Thai woman had undergone pterygium excision 26 years ago, with adjunctive mitomycin C, as well as an uneventful extracapsular cataract extraction in the same year. The patient developed a filtering bleb without glaucoma surgery or trauma approximately 25 years later. Anterior segment ocular coherence tomography illustrated a fistula connected between the bleb and anterior chamber at the scleral spur. The bleb was observed without further management, as no hypotony or bleb-related complications occurred. The symptoms/signs of bleb-related infection were advised.

CONCLUSIONS

 This is a case report of a rare novel complication of mitomycin C application. Conjunctival bleb formation from the reopening of surgical wound, which was related to the previous mitomycin C use, could occur after a few decades.

[The "Three Cherries Technique" for glaucoma drainage devices]

Small sponges are used to apply antimetabolites in order to reduce the risk of fibrosis in filtering glaucoma surgery. Due to the posterior location of the filtering bleb in glaucoma drainage implants, there is a risk that the sponges can dislocate in this area and cannot be retrieved after the exposure time has elapsed. We use the "three cherries technique" to minimize the risk. The term "three cherries technique" was coined by us and has not been used before in the literature. The three sponges that are used for mitomycin C application are each connected by single button sutures with a 7.0 vicryl thread. At the end of the application time, the sponges can be quickly removed by pulling the thread.

Scleral melt and uveal prolapse following 23-gauge pars plana vitrectomy

Purpose

To report a case of uncontrolled juvenile open angle glaucoma (JOAG), with secondary high axial myopia who presented with scleral melting and uveal prolapse post pars plana-vitrectomy.

Observations

A 17-year-old male juvenile glaucoma patient, not known to have any systemic disease underwent a right eye 23-gauge-pars plana vitrectomy for retinal detachment repair. Three weeks following his surgery he presented complaining of tearing and photophobia in the operated eye in the absence of any ocular pain. Clinical exam revealed enlarged sclerotomy sites with localized conjunctival and episcleral injection, scleral thinning and uveal prolapse. Infectious and serologic work up were obtained to rule out an infectious etiology or underlying autoimmune disease. Patient was successfully managed with topical steroids and a donor scleral patch graft.

Conclusion and importance

This report addresses multiple risk factors for a devastating complication that may occur in predisposed patients, with primary or secondary axial myopia and a compromised sclera. This group of patients can be at risk of post-operative scleral melting and thinning and should be identified pre-operatively and monitored closely during their post-operative course.

Corneal fibrosis abrogation by a localized AAV-mediated inhibitor of differentiation 3 (Id3) gene therapy in rabbit eyes in vivo

Previously we found that inhibitor of differentiation 3 (Id3) gene, a transcriptional repressor, efficiently inhibits corneal keratocyte differentiation to myofibroblasts in vitro. This study evaluated the potential of adeno-associated virus 5 (AAV5)-mediated Id3 gene therapy to treat corneal scarring using an established rabbit in vivo disease model. Corneal scarring/fibrosis in rabbit eyes was induced by alkali trauma, and 24 h thereafter corneas were administered with either balanced salt solution AAV5-naked vector, or AAV5-Id3 vector (n = 6/group) via an optimized reported method. Therapeutic effects of AAV5-Id3 gene therapy on corneal pathology and ocular health were evaluated with clinical, histological, and molecular techniques. Localized AAV5-Id3 gene therapy significantly inhibited corneal fibrosis/haze clinically from 2.7 to 0.7 on the Fantes scale in live animals (AAV5-naked versus AAV5-Id3; p < 0.001). Furthermore, AAV5-Id3 treatment significantly reduced profibrotic gene mRNA levels: α-smooth muscle actin (α-SMA) (2.8-fold; p < 0.001), fibronectin (3.2-fold; p < 0.001), collagen I (0.8-fold; p < 0.001), and collagen III (1.4-fold; p < 0.001), as well as protein levels of α-SMA (23.8%; p < 0.001) and collagens (1.8-fold; p < 0.001). The anti-fibrotic activity of AAV5-Id3 is attributed to reduced myofibroblast formation by disrupting the binding of E-box proteins to the promoter of α-SMA, a transforming growth factor-β signaling downstream target gene. In conclusion, these results indicate that localized AAV5-Id3 delivery in stroma caused no clinically relevant ocular symptoms or corneal cellular toxicity in the rabbit eyes.

AZD6738 Inhibits fibrotic response of conjunctival fibroblasts by regulating checkpoint kinase 1/P53 and PI3K/AKT pathways

Trabeculectomy can effectively reduce intraocular pressure (IOP) in glaucoma patients, the long-term surgical failure is due to the excessive proliferation and fibrotic response of conjunctival fibroblasts which causes the subconjunctival scar and non-functional filtering bleb. In this study, we demonstrated that AZD6738 (Ceralasertib), a novel potent ataxia telangiectasia and Rad3-related (ATR) kinase inhibitor, can inhibit the fibrotic response of conjunctival fibroblasts for the first time. Our in vitro study demonstrated that AZD6738 inhibited the level and the phosphorylation of checkpoint kinase 1 (CHK1), reduced TGF-β1-induced cell proliferation and migration, and induced apoptosis of human conjunctival fibroblasts (HConFs) in the high-dose group (5 μM). Low-dose AZD6738 (0.1 μM) inhibited the phosphorylation of CHK1 and reduce fibrotic response but did not promote apoptosis of HConFs. Further molecular research indicated that AZD6738 regulates survival and apoptosis of HConFs by balancing the CHK1/P53 and PI3K/AKT pathways, and inhibiting TGF-β1-induced fibrotic response including myofibroblast activation and relative extracellular matrix (ECM) protein synthesis such as fibronectin (FN), collagen Ⅰ (COL1) and collagen Ⅳ (COL4) through a dual pharmacological mechanism. Hence, our results show that AZD6738 inhibits fibrotic responses in cultured HConFs in vitro and may become a potential therapeutic option for anti-subconjunctival scarring after trabeculectomy.

Safety profile and efficacy of high-dose topical mitomycin-C for choanal atresia repair: A prospective cohort study

OBJECTIVES

To study the effect of dose-adjusted mitomycin-c (MMC) on the recurrence rate of choanal atresia (CA), and the complication rate associated with this concentration.

METHODS

This prospective cohort study was conducted between May 2012 and March 2020 at a tertiary referral center. It included patients of all ages who were diagnosed with CA and scheduled to undergo surgical repair. The MMC group received 4.0 mg/mL of topical MMC. Both groups were followed up for the surgical outcomes and complication rates.

RESULTS

Twenty-one patients (15 females) underwent 25 CA repair procedures. The mean age was 44.85 months (standard deviation = 72.85). MMC was used in 12 (57.1%) of 21 patients. Revision CA repair was warranted in three of the nine patients who did not receive topical MMC compared to one of the 12 patients who received topical MMC. The MMC group required 1.08 ± 0.29 surgeries (range, 1-2), whereas the non-MMC group required 1.44 ± 0.73 surgeries (range, 1-3). Functional success was achieved in 17 (81%) patients who remained symptom-free until their last follow-up visit.

CONCLUSION

High-concentration MMC was considered safe in the pediatric and adult populations. Although high-concentration MMC could reduce the need for revision surgery, further studies are required to determine whether the effect is significant in a larger sample population.

Ologen implant versus mitomycin C in combined trabeculectomy and phacoemulsification

Purpose:

To comparatively evaluate in Indian eyes with coexisting cataract and primary open-angle glaucoma the outcome of mitomycin C (MMC) and Ologen implant as adjunctives in combined phacoemulsification with trabeculectomy.

Methods:

Eyes with primary open-angle glaucoma that underwent trabeculectomy and phacoemulsification with IOL implantation with either MMC application or Ologen implant between June 2019 and February 2020 were followed up for 12 months. Thirty-four eyes of 34 participants were studied. The primary outcome was intraocular pressure (IOP), and the secondary outcomes were the number of ocular hypotensives, best distance visual acuity (BDVA), and bleb morphology.

Results:

In 16 eyes treated with MMC and 18 eyes treated with Ologen implant, it was observed that the mean postoperative IOP (14.62 ± 2.89 mm Hg with MMC and 14.56 ± 4.14 mm Hg with Ologen implant) was not significantly different in both groups (P = 0.47). Number of ocular hypotensives and BDVA were also comparable between the two groups. However, bleb morphology was better with Ologen implantation. One eye in the MMC group developed hypotony which was conservatively managed

Conclusion:

MMC and Ologen are both effective adjunctives in combined phaco-trabeculectomy. However, the Ologen implant provides better bleb health and safety.

Comparison of Surgical Outcomes of Sponge Application versus Subconjunctival Injection of Mitomycin-C during Combined Phacoemulsification and Trabeculectomy Surgery in Asian Eyes

Purpose:

To compare the outcomes of combined phacoemulsification–trabeculectomy surgery with intraoperative sponge-applied versus subconjunctival injection of mitomycin-C (MMC) in Asian eyes.

Methods:

This was a retrospective review of 95 eyes that consecutively underwent combined phacoemulsification–trabeculectomy surgery in a tertiary eye center in Singapore from January 2013 to June 2014. Data collected included intraocular pressure (IOP), best corrected visual acuity, and number of glaucoma medications. Outcome measures included postoperative IOP and complications at various timepoints up to 12 months after surgery.

Results:

Twenty eyes (21.1%) received 0.2 mg/ml subconjunctival MMC injection (“Group 1”) and 75 (78.9%) received 0.4 mg/ml sponge-applied MMC (“Group 2”). There was no difference between groups in demographics, IOP, and number of glaucoma medications preoperatively. There was a reduction in IOP at postoperative month (POM) 1, 6, and 12 in both the groups (POM12: Group 1, −2.8 ± 5.36 mmHg, P < 0.001; Group 2, −5.8 ± 6.29 mmHg, P = 0.054). At POM1, Group 2 showed a trend toward greater IOP reduction (−5.89 ± 7.67 mmHg vs. −1.55 ± 5.68 mmHg, P = 0.061). However, at both POM6 and POM12, there was no statistically significant difference in IOP reduction between the two groups. At POM12, complete success, defined as achieving an IOP of between 6 and 15 mmHg without the use of antiglaucoma medications, was achieved in 11 (55%) eyes in Group 1 and 48 (64%) in Group 2 (P = 0.9). There was a lower rate of postoperative hypotony in the Group 1 (0%) compared to Group 2 (8%) (P = 0.34).

Conclusion:

Combined phacoemulsification–trabeculectomy with subconjunctival MMC injection has comparable outcomes to that with sponge-applied MMC, with a similar reduction in IOP at 1, 6, and 12 months postoperatively and a lower postoperative complication rate.

RhoA/ROCK Signaling Regulates TGF-β1-Induced Fibrotic Effects in Human Pterygium Fibroblasts through MRTF-A

PURPOSE

The overexpression of transforming growth factor-beta1 (TGF-β1) after surgical excision often leads to excessive fibrosis, indicating the recurrence of pterygium. The aims of the present in vitro study were to investigate the role of RhoA/ROCK signaling in regulating fibrotic effects of primary human pterygium fibroblasts (HPFs), as well as to explore the possible mechanisms of these effects.

METHODS

Pterygium samples were obtained from surgery, and profibrotic activation was induced by TGF-β1. Cell proliferation was detected by CCK-8 assay; cell migration was detected by wound healing assay; quantitative real-time PCR and Western blot were used to detect the effects of TGF-β1 and the role of RhoA/ROCK signaling in the synthesis of alpha-smooth muscle actin (a-SMA), type I and III collagen (COL1 and COL3), and matrix metalloproteinase-9 (MMP9) in HPFs. The changes of signaling pathways were detected by Western blot; and pharmaceutical inhibition of RhoA/ROCK signaling and its downstream MRFT-A/SRF transcription pathway were used to assess their possible mechanism in HPFs fibrosis.

RESULTS

ROCK inhibitor Y-27632 decreased TGF-β1-induced cell proliferation and migration, reduced the TGF-β1-induced expression of profibrotic markers in HPFs, and suppressed TGF-β1-induced nuclear accumulation of Myocardin-related transcription factor A (MRTF-A) as well as accompanied elevation of F/G-actin ratio in HPFs. MRTF-A/Serum response factor (SRF) inhibitor CCG-100602 attenuated the TGF-β1-induced α-SMA expression and reduced myofibroblast activation in HPFs.

CONCLUSIONS

RhoA/ROCK signaling played a pivotal role in TGF-β1-induced fibrosis and myofibroblast activation in HPFs at least in part by inactivating the downstream MRTF-A/SRF transcriptional pathway.

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

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

History, presence, and future of mitomycin C in glaucoma filtration surgery

PURPOSE OF REVIEW

Mitomycin C (MMC) is an alkylating agent with extraordinary ability to crosslink DNA, preventing DNA synthesis. By this virtue, MMC is an important antitumor drug. In addition, MMC has become the gold standard medication for glaucoma filtration surgery (GFS). This eye surgery creates a passage for drainage of aqueous humor (AqH) out of the eye into the sub-Tenon's space with the aim of lowering the intraocular pressure. A major cause of failure of this operation is fibrosis and scarring in the sub-Tenon's space, which will restrict AqH outflow. Intraoperative application of MMC during GFS has increased GFS success rate, presumably mainly by reducing fibrosis after GFS. However, still 10% of glaucoma surgeries fail within the first year.

RECENT FINDINGS

In this review, we evaluate risks and benefits of MMC as an adjuvant for GFS. In addition, we discuss possible improvements of its use by adjusting dose and method of administration.

SUMMARY

One way of improving GFS outcome is to prolong MMC delivery by using a drug delivery system.

Safety and efficacy of combination of suberoylamilide hydroxyamic acid and mitomycin C in reducing pro-fibrotic changes in human corneal epithelial cells

Corneal haze post refractive surgery is prevented by mitomycin c (MMC) treatment though it can lead to corneal endothelial damage, persistent epithelial defects and necrosis of cells. Suberanilohydroxamic acid (SAHA) however has been proposed to prevent corneal haze without any adverse effects. For clinical application we have investigated the short and long term outcome of cells exposed to SAHA. Human donor cornea, cultured limbal epithelial cells, corneal rims and lenticules were incubated with SAHA and MMC. The cells/tissue was then analyzed by RT-qPCR, immunofluorescence and western blot for markers of apoptosis and fibrosis. The results reveal that short term exposure of SAHA and SAHA + MMC reduced apoptosis levels and increased αSMA expression compared to those treated with MMC. Epithelial cells derived from cultured corneal rim that were incubated with the MMC, SAHA or MMC + SAHA revealed enhanced apoptosis, reduced levels of CK3/CK12, ∆NP63 and COL4A compared to other treatments. In SAHA treated lenticules TGFβ induced fibrosis was reduced. The results imply that MMC treatment for corneal haze has both short term and long term adverse effects on cells and the cellular properties. However, a combinatorial treatment of SAHA + MMC prevents expression of corneal fibrotic markers without causing any adverse effect on cellular properties.

Primary and Secondary Optic Nerve Sheath Meningioma

Objective  This study was aimed to review issues relating to the recognition, radiographic diagnosis, monitoring, and management of primary and secondary optic nerve sheath meningioma (ONSM). Design  This study is a review of peer-reviewed literature combined with illustrative case studies. Participants and Methods  A literature search was conducted via the PubMed database using pertinent search terms. Selected articles were limited to those written or translated into English. Additional works cited within articles were also included. Individual cases were drawn from the experience of a tertiary academic neuroophthalmic and orbital practice. Tables summarize radiotherapeutic and surgical studies, excluding single case reports and studies focusing on meningioma of intracranial origin. Main Outcome Measurements  Review of reported surgical and radiotherapeutic series is the primary measurement. Results  The natural history of optic nerve sheath meningiomas is primarily characterized by progressive ipsilateral vision loss. Diagnosis is typically based on radiographic imaging findings, with biopsy remaining indicated in some patients. Management strategies may include observation, radiation, and/or surgical intervention, or a combination of these approaches. The role of surgery, especially with respect to primary ONSM (pONSM), remains controversial. Advancement of radiotherapy techniques has shifted modern treatment paradigms in pONSM toward radiation as primary treatment, as surgical outcomes are inferior in major studies. Although radiation remains the treatment of choice in many cases, selected patients may benefit from surgery, especially in the setting of secondary ONSM (sONSM). Conclusion  A wide variety of radiotherapeutic and surgical treatment modalities for ONSM exist. The specific indications for each management strategy continue to be redefined.

Differential Effects of TGF-β2 on the Low-Density Lipoprotein Receptor Expression in Three Types of Human Subconjunctival Fibroblasts

Purpose: To investigate whether TGF-β2 had a different effect on the expression levels of low-density lipoprotein receptor (LDLr) in the subconjunctival fibroblasts from glaucoma patients who underwent a reoperation (RGSFs) compared with those from glaucoma patients who underwent first filtering surgery (GSFs) and control patients with cataracts (HSFs). Methods: Human subconjunctival fibroblasts were obtained from the three groups of patients. Different concentrations of TGF-β2 were added to the fibroblasts for 1, 3, and 5 days. The proliferation of the fibroblasts was determined by CCK-8 assays. Real-time PCR and western blotting were performed to analyze the mRNA and protein levels of LDLr. The uptake of DiI-labeled LDL was determined by confocal microscopy. Results: The results revealed that under TGF-β2 exposure, fibroblast proliferation was positively correlated with LDLr expression (all p < .001). The LDLr mRNA and protein levels were affected by TGF-β2 in a concentration-dependent and time-dependent manner in the RGSFs, GSFs and HSFs. The maximal expression of LDLr after TGF-β2 stimulation was consistent with the peak uptake of DiI-LDL, which was obviously highest in the RGSFs, followed by the GSFs, and then the HSFs (all p < .05). All 3 groups took up DiI-LDL in a similar time-dependent manner, with maximal uptake at 6 h following DiI-LDL incubation (all p < .05). In addition, there were significant differences in the LDLr protein levels in the subconjunctival tissues isolated from the glaucoma patients during reoperation, the glaucoma patients during first filtering surgery and the control patients at day 3 (p < .05). The highest protein expression of LDLr was observed in the RG group. Conclusion: These data suggested that the RGSFs had the highest LDLr expression and the highest peak uptake of LDL among three groups. The LDLr-drug-LDL delivery system could potentially be used for targeted delivery of antimetabolite agents in anti-scarring therapy for glaucoma patients after filtering surgery.

5-year efficacy of all surface laser ablation with cross-linking (ASLA-XTRA) for the treatment of myopia

Background

The purpose of our study is to examine the long (5-year) efficacy of the all surface laser ablation (ASLA) combined with accelerated cross-linking (CXL) for the treatment of myopia without the use of mitomycin-C (MMC).

Methods

This retrospective study consisted of 202 eyes of 118 myopic (SD: 2.41, range: − 1.50 to − 12.75 D) patients (44 males, 74 females). Mean age was 28.50 years (SD: 6.45, range: 18 to 51 years) that underwent ASLA with accelerated CXL for the treatment of their myopia.

Results

The patients underwent routine postoperative assessment on the 1st, 3rd, 7th day and in the 1st, 3rd, 6th and 12th month, 30th month (±6 months), 4th and 5th year. The mean spherical equivalent (SEq) refractive error changed from − 6.41 ± 2.41 D preoperatively to − 0.02 ± 0.53 D at 5 years postoperatively. The haze score was 0.18, 0.25 and 0.28 at 1, 3 and 6 months postoperatively. At 12 months after the treatment, no eyes had significant corneal haze and in all the following postoperative time intervals the haze traces were gone.

Conclusion

ASLA combined with accelerated CXL (ASLA-XTRA) appears to be safe, efficacious and offering very good refractive results. The potential additional benefits of this modality are the stabilizing effect of the refraction and its sterilization effect on the treated cornea without the potential side effects of MMC.

Intraoperative injection versus sponge-applied mitomycin C during trabeculectomy: One-year study

Purpose

To determine the safety and efficacy of mitomycin C (MMC) injection versus sponge during trabeculectomy.

Methods

It is a prospective analysis of patients who underwent trabeculectomy with MMC and followed up for 1 year, divided into two groups, namely, group 1- injection (n = 21), group 2-> sponge (n = 21). The same concentration of MMC was used for both groups. Inclusion criteria were trabeculectomies with MMC for intraocular pressure (IOP) control in eyes with glaucoma (primary + secondary) with a follow-up of 1 year.

Results

Mean preoperative IOP in group 1 was 29.00 ± 11.92 mmHg and group 2 was 25.87 ± 11.09 mmHg, which reduced to 12.19 ± 4.03 and 15.56 ± 10.72 mmHg at final visit with P value of 0.0002 and 0.001, respectively. Mean preoperative number of antiglaucoma medications was 2.4 ± 0.87 in group 1 and 2.3 ± 0.96 in group 2, which reduced to 0.38 ± 0.5 and 0.91 ± 0.85 with P value of 0.001 and 0.0003, respectively. The complete success rate was 52.4% in the injection group and 26.1% in the sponge group at end of 1 year. Overall, success rate (complete + qualified) was 90.5% and 87% in group 1 and group 2 at final visit. All major complications were encountered in sponge group. 1 (11.1%) patient developed choroidal detachment and one had malignant glaucoma which got resolved by medical management. 33.3% cases had encapsulated bleb which received bleb needling. 44.4% cases underwent Argon laser suture lysis postoperatively.

Conclusion

The MMC injection may be as safe and as effective as conventional sponge application with comparable estimated complete treatment success.

Successful use of topical mitomycin C for the treatment of a putative neoplastic vascular mass on the nictitating membrane of a dog

A nine-year-old female desexed Great Dane presented with a painful, proliferative, soft red putative neoplastic vascular mass on the nictitating membrane. Three 7-day cycles of the topical cytotoxic drug mitomycin C 0.04%, applied four times daily to the lesion using a low-dose alternate-week pulse therapy, brought about rapid remission of the lesion. The lesion was still in remission at time of euthanasia some 13 months later.

Efficacy and Safety of the Local Application of Mitomycin C to Recurrent Esophageal Strictures in Children

OBJECTIVES

Research on long-term use of mitomycin C (MC) for recurrent esophageal stenoses is limited. We assessed the long-term efficacy and safety of local application of MC for recurrent esophageal stenoses in children.

METHODS

This was a retrospective study of 39 patients (17 girls) with a median age of 19.5 months (range: 2.4-196.0) at the time of MC application. The etiologies of stenosis were esophageal atresia (n = 25), caustic ingestion (n = 9), congenital esophageal stenosis (n = 3), and other causes (n = 2). Stenosis was single in 35 (90%) patients and multiple in 4 (10%). Before MC, patients underwent multiple repeated dilations (median: 3 dilations per child [range: 2-26]) over a median period of 7 months (range: 2.6-49.3). Treatment success was defined a priori as a reduction in the number of dilations over the same period from before to after the application of MC.

RESULTS

For 26 (67%) patients, the application of MC was considered a success: 102 versus 17 dilatations (P < 0.0001). Sixteen (41%) patients never required additional dilation during the follow-up after MC application (median: 3.1 years [range: 0.6-8.5]). No complication related to MC was observed. Biopsies at the site of MC application were performed at maximal follow-up in 16 patients and revealed no dysplasia. Three factors were associated with success of MC: single stenosis, short stenosis, and esophageal atresia type III.

CONCLUSIONS

This study is the largest series reported showing that topical application of MC is an efficient and safe treatment for recurrent esophageal stenosis in children.

Bromfenac Inhibits TGF-β1-Induced Fibrotic Effects in Human Pterygium and Conjunctival Fibroblasts

Purpose

Nonsteroidal anti-inflammatory drugs (NSAIDs) have shown antifibrotic effects on several diseases. The aims of the present in vitro study were to investigate the antifibrotic effects of bromfenac (a kind of NSAID) on primary human pterygium fibroblasts (HPFs) and primary human conjunctival fibroblasts (HConFs), as well as to explore the possible mechanisms of these effects.

Methods

The cells used in this study were primary HPFs and HConFs, and profibrotic activation was induced by transforming growth factor-beta1 (TGF-β1). Western blot, quantitative real-time PCR, and immunofluorescence (IF) assays were used to detect the effects of TGF-β1 and bromfenac on the synthesis of fibronectin (FN), type III collagen (COL3), and alpha-smooth muscle actin (α-SMA) in HPFs and HConFs; the changes of signaling pathways were detected by Western blot; cell migration ability was detected by wound healing assay; cell proliferation ability was detected by CCK-8 assay; and pharmaceutical inhibitions of the downstream signaling pathways of TGF-β1 were used to assess their possible associations with the effects of bromfenac.

Results

Bromfenac suppressed the TGF-β1-induced protein expression of FN (0.59 ± 0.07 folds, P = 0.008), COL3 (0.48 ± 0.08 folds, P = 0.001), and α-SMA (0.61 ± 0.03 folds, P = 0.008) in HPFs. Bromfenac also attenuated TGF-β1-induced cell migration (0.30 ± 0.07 folds, P < 0.001), cell proliferation (0.64 ± 0.03 folds, P = 0.002) and the expression levels of p-AKT (0.66 ± 0.08 folds, P = 0.032), p-ERK1/2 (0.69 ± 0.11 folds, P = 0.003), and p-GSK-3β-S9 (0.65 ± 0.10 folds, P = 0.002) in HPFs. PI3K/AKT inhibitor (wortmannin) and MEK/ERK inhibitor (U0126) reduced the TGF-β1-induced synthesis of FN, COL3, and α-SMA in HPFs. All the results were similar in HConFs.

Conclusions

Bromfenac protects against TGF-β1-induced synthesis of FN, α-SMA, and COL3 in HPFs and HConFs at least in part by inactivating the AKT and ERK pathways.

Development of a biodegradable antifibrotic local drug delivery system for glaucoma microstents

To prevent implant failure due to fibrosis is a major objective in glaucoma research. The present study investigated the antifibrotic effects of paclitaxel (PTX), caffeic acid phenethyl ester (CAPE), and pirfenidone (PFD) coated microstent test specimens in a rat model. Test specimens based on a biodegradable blend of poly(4-hydroxybutyrate) biopolymer and atactic poly(3-hydroxybutyrate) (at.P(3HB)) were manufactured, equipped with local drug delivery (LDD) coatings, and implanted in the subcutaneous white fat depot. Postoperatively, test specimens were explanted and analyzed for residual drug content. Fat depots including the test specimens were histologically analyzed. In vitro drug release studies revealed an initial burst for LDD devices. In vivo, slow drug release of PTX was found, whereas it already completed 1 week postoperatively for CAPE and PFD LDD devices. Histological examinations revealed a massive cell infiltration in the periphery of the test specimens. Compact fibrotic capsules around the LDD devices were detectable at 4–36 weeks and least pronounced around PFD-coated specimens. Capsules stained positive for extracellular matrix (ECM) components. The presented model offers possibilities to investigate release kinetics and the antifibrotic potential of drugs in vivo as well as the identification of more effective agents for a novel generation of drug-eluting glaucoma microstents.

Exogenous Tissue Inhibitor of Metalloproteinase-2 Affects Matrix Metalloproteinase-2 Expression in Conjunctival Filtering Blebs and Bleb Scarring in Rats

Objective

To examine the effect of tissue inhibitor of metalloproteinase-2 (TIMP-2) on conjunctival filtering bleb scarring.

Methods

A model of conjunctival filtering bleb was established whereby rats were injected with saline, blank adenoviral vector, or adenoviral vector carrying TIMP-2 into the bleb. Filtration bleb formation and matrix metalloproteinase-2 (MMP-2) expression were examined.

Results

All operated eyes formed obvious elevated blebs on day 1. In the normal saline group, empty plasmid group, and gene transfection group maintenance time of filtrating blebs was 5–14, 5–14, and 6–16 days, and average survival time was 8.24, 8.16, and 9.44 days, respectively. MMP-2 expression increased slightly in the gene transfection group at 3 and 5 days after surgery, reached a peak after 14 days, and then gradually decreased. MMP-2 expression was weakly positive in the normal conjunctival epithelium, but was hardly detected in the lamina propria. Seven days after surgery, the epithelium and lamina propria of the conjunctival filtering bleb exhibited strong positive expression in the empty plasmid group but only weak expression in the adenovirus group.

Conclusion

Exogenous TIMP-2 interfered with local MMP-2 expression, delaying peak expression of MMP-2 and slowing the scarring of filtering blebs during wound healing of subconjunctival tissue.

Marketed drugs used for the management of hypercholesterolemia as anticancer armament

The design of novel pharmacologic agents as well as their approval for sale in markets all over the world is a tedious and pricey process. Inevitably, oncologic patients commonly experience unwanted effects of new anticancer drugs, while the acquisition of clinical experience for these drugs is largely based on doctor–patient partnership which is not always effective. The repositioning of marketed non-antineoplastic drugs that hopefully exhibit anticancer properties into the field of oncology is a challenging option that gains ground and attracts preclinical and clinical research in an effort to override all these hindrances and minimize the risk for reduced efficacy and/or personalized toxicity. This review aims to present the anticancer properties of drugs used for the management of hypercholesterolemia. A global view of the antitumorigenicity of all marketed antihypercholesterolemic drugs is of major importance, given that atherosclerosis, which is etiologically linked to hypercholesterolemia, is a leading worldwide cause of morbidity and mortality, while hypercholesterolemia and tumorigenesis are known to be interrelated. In vitro, in vivo and clinical literature data accumulated so far outline the mechanistic basis of the antitumor function of these agents and how they could find application at the clinical setting.

Intraoperative Injection vs Sponge-applied Mitomycin C during Trabeculectomy: One-year Study

AIM

To determine the safety and efficacy of intraoperative injection of mitomycin C (MMC) against conventional sponge-applied MMC during trabeculectomy.

MATERIALS AND METHODS

This study was a retrospective, comparative case series. Thirty eyes with primary open-angle glaucoma underwent consecutive trabeculectomies with MMC injection (injection group), and thirty eyes with sponge-applied MMC were as controls (sponge group). Data were collected preoperatively and postoperatively at 1 day, 1 week, 1 month, 3 months, 6 months, and 1 year after surgery. Demographic data, applanation intraocular pressure (IOP), best-corrected visual acuity (VA), number of glaucoma medications, postoperative interventions, postoperative complications, and number of visits within 3 months were recorded. In order to stratify data, proportion of eyes achieving >30% IOP reduction from baseline with or without glaucoma medications was calculated and defined as surgical success.

RESULTS

Mean IOP reduction at 1 year was significant in both the injection and sponge groups from baseline (46.8 and 37.8% respectively). The injection group had overall lower postoperative IOP and comparable complete treatment success, defined as achieving >30% IOP reduction without glaucoma medications (p = 0.941). The number of postoperative visits within 3 months and the proportion of eyes needing 5-fluorouracil (5-FU) intervention were significantly lower in the injection group (p = 0.03, p = 0.04 respectively).

CONCLUSION

Injection of MMC was as safe and effective as sponge application with comparable estimated complete treatment success, less need for visits within 3 months, and 5-FU intervention.

CLINICAL SIGNIFICANCE

Surgeons may consider intraopera-tive injection of MMC in appropriate patient cohorts given comparable safety and efficacy and several advantages over traditional sponge application. Further study in a prospective, larger, long-term manner is necessary to assess this modality.How to cite this article: Khouri AS, Huang G, Huang LY. Intraoperative Injection vs Sponge-applied Mitomycin C during Trabeculectomy: One-year Study. J Curr Glaucoma Pract 2017;11(3):101-106.

Scleral resection in chronic central serous chorioretinopathy complicated by exudative retinal detachment

BACKGROUND

Effective therapeutic options are limited for the management of chronic central serous chorioretinopathy (CSCR) complicated by exudative retinal detachments (RD). The authors describe the resolution of one such case following partial thickness scleral resection with mitomycin C.

CASE PRESENTATION

This 39-year-old male presented with a unilateral inferior exudative RD in the right eye. There was no history of steroid use either locally or systemically. The fundus fluorescein angiogram showed window defects and leaks typical of chronic CSCR. The axial length was 21.06 mm in the right eye and 21 mm in the left eye. Thickening of the ocular coats was evident on ocular ultrasound. Considering an axial length in the borderline-low range inferotemporal and inferonasal partial thickness scleral resection with mitomycin C was performed. The exudative RD resolved at 4 months.

CONCLUSION

Partial thickness scleral resection may be considered as an option for treating chronic CSCR patients with borderline-low axial length complicated by exudative RD.

Practice patterns in endoscopic dacryocystorhinostomy: survey of the American Rhinologic Society

BACKGROUND

The introduction of advanced endoscopic techniques has facilitated significant growth in endoscopic dacryocystorhinostomy (EnDCR). The purpose of this study is to evaluate clinical practice patterns of otolaryngologists performing EnDCR.

METHODS

A 25-item survey was electronically disseminated to the American Rhinologic Society (ARS) membership from November 17, 2014 to December 14, 2014. The target group encompassed 1157 ARS members.

RESULTS

A total of 85 (7.3%) physicians completed the survey. EnDCR was performed by 87% of respondents. The annual average number of EnDCR cases ranged from 1 to 10 in 65% of respondents, 11 to 25 in 15%, 26 to 50 in 6%, and >50 in 1%. A total of 48% of respondents had some to a lot of DCR exposure during training, and 60% had completed a rhinology fellowship. Respondents frequently perform preoperative nasal endoscopy and computed tomography (CT) imaging, but very infrequently perform ophthalmologic workup. Lacrimal stents were used often or always in 80%, with 38% keeping stents in place for 6 to 8 weeks. The mucosal flap preservation technique was used often or always in 40%. Topical antimetabolites were used often or always in only 1%. Ophthalmology was present in most cases to perform lacrimal intubation. Postoperative antibiotics, topical ophthalmic steroids, and oral steroids were prescribed often or always in 62%, 47%, and 23%, respectively. Postoperative endoscopic debridement was performed often or always in 69%. A total of 81% of respondents followed DCR patients for >2 months, with 17% following these patients for >1 year.

CONCLUSION

There is widespread integration of EnDCR procedures into rhinologic clinical practice among respondents. EnDCR practice patterns demonstrate moderate variation. In conjunction with evidence-based medicine, these trends can highlight areas of controversy and help advance patient care.

Electron microscopic features of nasal mucosa treated with topical and circumostial injection of mitomycin C: implications in dacryocystorhinostomy

PURPOSE

To evaluate the ultrastructural effects of topical and circumostial injection of mitomycin C (COS-MMC) on nasal mucosa and compare them with the controls. The study also aimed at classifying the subcellular effects in detail.

METHODS

The nasal mucosa of 6 patients were subjected to 0.02% of mitomycin C for 3 minutes (3 patients) and 0.02% COS-MMC (3 patients) as per standard protocol, during endoscopic dacryocystorhinostomy. Normal nasal mucosa from untreated areas (2 each from topical and COS-MMC groups) were taken as controls after harvesting the treated areas. Full thickness tissues (5 mm × 5 mm) were collected for transmission electron microscopy, and ultrastructural effects were evaluated.

RESULTS

Both topical and COS-MMC showed significant and distinct ultrastructural changes involving the epithelial, glandular, vascular, and fibrocollagenous tissues compared with the controls. There were profound changes within fibroblasts with intracellular edema, pleomorphic and vesicular mitochondria, dilated smooth and rough endoplasmic reticulum, and chromatin condensation. In addition, COS-MMC samples showed subepithelial hypocellularity with limited disorganization of structure. The changes in both the MMC groups were restricted to treated areas only.

CONCLUSIONS

Both topical and COS-MMC show profound changes in nasal mucosa with more marked changes in COS-MMC group. These changes being limited in nature may help in enhancing the success of dacryocystorhinostomy by preventing cicatricial changes of the ostium, especially in high-risk cases such as revision and post-traumatic dacryocystorhinostomy.

Outcomes of Trabeculectomy With Transconjunctival Application Versus Subconjunctival Application of Mitomycin C

PURPOSE

To compare outcomes and complication rates of trabeculectomy with either transconjunctival mitomycin C (MMC) or subconjunctival MMC application.

METHODS

Retrospective cohort study-35 eyes in subconjunctival group and 29 eyes in transconjunctival group. All surgeries were performed by 1 surgeon (E.A.) at 1 center with an average follow-up duration of 40 to 51 months.

RESULTS

The mean percentage intraocular pressure reduction at final follow-up was with 44.4±25.3% reduction in the subconjunctival group compared with 48.0±24.6% reduction in the transconjunctival group, with no statistical significant difference between the 2 groups (P=0.57). Both groups also showed a >40% reduction in intraocular pressure in approximately 67% of eyes. There were no cases of endophthalmitis. There was 1 reported case of choroidal hemorrhage following subconjunctival application of MMC. There were similar low rates of postoperative bleb leakage and requirement for postoperative application of 5-fluorouracil. There was a greater incidence of hyphema in the subconjunctival group (5 vs. 1) as well as choroidal effusions (8 vs. 4). One patient underwent revision of trabeculectomy and this was in the subconjunctival group.

CONCLUSION

Transconjunctival application of MMC offers a safe and effective method of performing trabeculectomy with adjunctive MMC with lower rates of complication than subconjunctival application.

Surgery on the Trabecular Meshwork: Histopathological Evidence

Juxtacanalicular (JXT) trabecular meshwork and endothelial lining of Schlemm's canal have been cited as the loci of aqueous outflow resistance, both in a normal as well as a glaucomatous eye. In this review, we attempt to understand the currently available surgical modalities in light of the available histopathological evidence, regarding localization of outflow resistance. How to cite this article: Bhartiya S, Ichhpujani P, Shaarawy T. Surgery on the Trabecular Meshwork: Histopathological Evidence. J Curr Glaucoma Pract 2015;9(2):51-61.

Potential risk of mitomycin C at high concentrations on peripheral nerve structure

Although the local application of mitomycin C may prevent epidural adhesion after laminectomy, mitomycin C can induce neurotoxicity in optic and acoustic nerves at high concentrations. To determine the safe concentration range for mitomycin C, cotton pads soaked with mitomycin C at different concentrations (0.1, 0.3, 0.5, and 0.7 mg/mL) were immediately applied for 5 minutes to the operation area of rats that had undergone laminectomy at L₁. Rat sciatic nerves, instead of dorsal nerves, were used in this study. The results showed that mitomycin C at 0.1-0.5 mg/mL did not damage the structure and function of the sciatic nerve, while at 0.7 mg/mL, mitomycin C significantly reduced the thickness of the sciatic nerve myelin sheath compared with lower concentrations, though no functional change was found. These experimental findings indicate that the local application of mitomycin C at low concentrations is safe to prevent scar adhesion following laminectomy, but that mitomycin C at high concentrations (> 0.7 mg/mL) has potential safety risks to peripheral nerve structures.

Use of adjunctive mitomycin C in external dacryocystorhinostomy surgery compared with surgery alone in patients with nasolacrimal duct obstruction: A prospective, double-masked, randomized, controlled trial

BACKGROUND

The most common cause for the failure of external dacryocystorhinostomy (DCR) surgery is the formation of granulation tissue at the osteotomy site or common canaliculus.

OBJECTIVES

The aims of this study were to assess the efficacy of intraoperative adjunctive mitomycin C (MMC) treatment in external DCR surgery and to compare this procedure with the standard DCR procedure alone in the long term (1 year).

METHODS

In this prospective, double-masked, randomized, controlled trial, patients with primary acquired nasolacrimal duct obstruction were randomized (using a random number table) into 2 groups based on surgical procedure. In the MMC group, intraoperative adjunctive MMC 0.2 mg/mL was applied to the osteotomy site for 30 minutes. The control group underwent standard DCR procedure only. The results of the DCR surgeries were assessed using objective findings (eg, cessation of excessive tearing via nasolacrimal duct irrigation and the improvement in height of tear meniscus) and subjective symptoms (asking patients to describe the degree of tearing improvement). Both the patients and the researchers who were assessing the study outcomes were masked to treatment group.

RESULTS

One hundred eyes of 100 Turkish patients were assessed and equally randomized to the MMC (27 women, 23 men; mean [SD] age, 47.0 [7.6] years) and control (26 women, 24 men; mean age, 46.6 [8.8] years) groups. The follow-up period was not significantly different between the MMC and the control groups (13.1 [1.1] vs 13.2 [1.4] months). Significantly more eyes in the MMC group than the control group remained symptom-free throughout the 1-year follow-up period (45/50 [90%] vs 33/50 [66%]; P=0.005). Significantly more patients in the control group than the MMC group had an improvement in symptoms at the 1-year follow-up (8/50 [16%] vs 2/50 [4%] eyes; P=0.005). Based on the patency of the drainage system, the success rate was significantly greater in the MMC group than the control group (48/50 [96%] vs 42/50 [84%]; P=0.005). Based on nasolacrimal duct irrigation, significantly fewer patients in the MMC group than the control group had an enclosed naso-lacrimal duct (2/50 [4%] vs 8/50 [16%]). No adverse effects (eg, abnormal nasal bleeding, mucosal necrosis, infection) or any other surgical adverse events were observed.

CONCLUSIONS

In the management of these patients with primary acquired nasolacrimal duct obstruction, adjunctive intraoperative MMC application with standard DCR surgery had a significantly higher success rate than did standard DCR surgery alone. Further large, double-masked, randomized studies are needed to confirm these findings.

Corneal Debridement Update: Adjuvant Therapies and Wound Healing

Corneal debridement techniques have seen evolution in instrumentation and indication. Although the techniques themselves are simple and usually effective, there is often the need for adjuvant topical therapies to augment healing and/or prevent recurrence of disease. To better understand the requirement for adjuvant therapies, the current theories of corneal wound healing are reviewed.

Canaloplasty with intraoperative low dosage mitomycin C: a retrospective case series

PURPOSE

To evaluate the safety and preliminary efficacy of intraoperative mitomycin C (MMC) in conjunction with canaloplasty for the treatment of open-angle glaucoma.

METHODS

Observational case series. A microcatheter was used to viscodilate the full circumference of Schlemm canal and to place a trabecular meshwork tensioning suture. Low dosage MMC was applied beneath the superficial scleral flap before dissecting the second, deep scleral flap and accessing Schlemm canal. Qualifying preoperative intraocular pressures (IOPs) were at least 16 mm Hg with a historical maximum IOP of at least 21 mm Hg. Primary outcome measures including visual acuity and adverse events are reported for a 12-month postoperative period. Secondary outcome measures included IOP and glaucoma medication usage.

RESULTS

In 20 eyes of 20 consecutive patients, adverse events were generally transient and not sight threatening. With the use of MMC, there was an increased rate of hypotony as compared with reported results of prior canaloplasty studies. The mean logMAR best corrected visual acuity at baseline was 0.07 ± 0.12 with a mean of 0.09 ± 0.13 at 12 months (P=0.679). Mean IOP decreased from a preoperative value of 23.4 ± 4.3 mm Hg on 2.2 ± 1.2 antiglaucoma medications to 13.4 ± 4.3 mm Hg on no medications at 12 months. At all intervals, IOP and medication use results were significantly reduced versus baseline (P<0.001).

CONCLUSIONS

The adjunctive use of MMC in canaloplasty is safe and effective.

Target drug delivery system as a new scarring modulation after glaucoma filtration surgery

Background

Excessive wound healing following glaucoma filtration surgery is the main determinant of surgical failure, resulting from the activation of human Tenon's capsule fibroblasts (HTFs). To mitigate the excessive wound healing, the topicall use of antiproliferative agents, such as mitomycin C (MMC) and 5-fluorouracil (5-FU), has increased the surgery success rate, but the traditional administration of these agents can result in a variety of toxicities with nonspecific damage. However, modulation of the wound healing process to prevent excessive fibroblast proliferation and scar formation can play a major role in improving the outcome of surgery. Therefore, the search for alternative modes of drug delivery and new agents is needed to minimize the ocular complications and improve the success of surgery. We have shown that there is a postoperative overexpression of the LDL receptor (LDLr) in the activated HTFs may provide a novel target for drug delivery systems.

Presentation of the Hypothesis

We hypothesize that antifibrotic agents (MMC) encapsulated in LDLr targeting drug delivery system (LDL-MMC-chitosan nanoparticles) may be proposed in anti-scarring therapy to increase the safety and effectiveness and to reduce toxicity.

Testing the Hypothesis

A chitosan-based polymeric predrug of MMC was synthesized and its cytotoxicity was proved to be low. In addition, we propose hyaluronic acid film as a container to release LDL-MMC-chitosan nanoparticles gradually at subconjunctival filtering site after glaucoma filtration surgery to eliminate the LDL-MMC-chitosan nanoparticles.

Implications of the Hypothesis and discussion

This strategy can be applicable to anti-scarring therapy during excessive conjunctival wound healing. This hypothesis integrates advantages of the targeting drug delivery and antifibrotic agents, such as high efficiency, convenience, and lower the toxicity.

Dynamic alteration of low-density lipoprotein receptor after exposure to transforming growth factor-beta2 in human Tenon's capsule fibroblasts

PURPOSE

The present study investigated dynamic alteration of low-density lipoprotein receptor and its binding and uptake of low-density lipoprotein (LDL) after exposure to transforming growth factor-beta(2) (TGF-beta(2)) in human Tenon's capsule fibroblasts.

METHODS

Tenon's capsule fibroblasts obtained from elective cataract surgery patients were cultured and stimulated with different concentrations (0.1-10 ng/mL) of TGF-beta(2) for 24, 48, and 72 h. The LDLr mRNA and protein levels were analyzed by relative quantification real-time RT-PCR and Western blot analysis, respectively. The binding and uptake of DiO (3,3'-dioctadecyloxacarbocyanine)-labeled LDL was assessed by confocal microscopy.

RESULTS

Real-time RT-PCR and Western blot analyses showed similar results revealing that after exposure to TGF-beta(2), the expression of protein and mRNA of LDLr occurred in a concentration-dependent and time-dependent manner with a peak at a concentration of 1.0 ng/mL at 72 h in Tenon's capsule fibroblasts. Confocal microscopy showed that DiO-LDL binding and uptake were time-dependent, reaching saturation at approximately 6 h.

CONCLUSIONS

This study shows that LDLrs were overexpressed in the activated Tenon's capsule fibroblasts in a concentration-dependent and time-dependent manner after exposure to TGF-beta(2). The results suggest that LDLr in the activated Tenon's capsule fibroblasts may become a novel focus as a target receptor for controlled drug delivery, particularly in anti-scarring therapy during excessive conjunctival wound healing.

Paclitaxel inhibits growth, migration and collagen production of human Tenon's fibroblasts--potential use in drug-eluting glaucoma drainage devices

OBJECTIVE/AIM

One of the factors limiting the long-term success of glaucoma drainage devices and traditional filtering surgery is the tendency of bleb encapsulation. Glaucoma shunts present an opportunity of introducing drug-eluting mechanisms for a lasting exposure of the bleb to anti-proliferative substances. The aim of this in vitro study was to investigate the effects of short- and long-term exposure of primary cultures of human Tenon's fibroblasts to different concentrations of paclitaxel on cell proliferation, migration, collagen production and cytotoxicity, in order to evaluate the suitability of the drug for the use in such a device.

MATERIALS/METHODS

Seven individual primary cultures of human Tenon's fibroblasts were observed over the course of 1 week after administering paclitaxel concentrations varying from 10(-9) mol/l to 10(-6) mol/l for either 1 hour or continuously. Relative cell count and migration across a cell-free area introduced by scratching through a confluent cell layer were determined every 24 hours, using photomicrographs of the cells for each concentration and exposure time. Soluble collagen concentration in the cell culture medium was determined using a Sircol collagen assay 72 hours after paclitaxel exposure. Cytotoxicity of the compound was assessed by flow cytometry using dual staining with annexin V-FITC and propidium iodide.

RESULTS

Paclitaxel dose-dependently inhibited both proliferation and migration of the cells. Cell count was reduced at all concentrations and both exposure times (p = 0.001); similarly, all but two concentrations of paclitaxel caused a significant reduction of cell migration (p < 0.001). This may be explained in part by the dose- and time-dependent induction of apoptosis in up to 23.7% of the cells (maximal effect at 10(-6) mol/l, 7 days after exposure). Collagen production was significantly reduced at all concentrations and at both exposure times. However, no statistically significant difference was observed between any of the concentrations, indicating that this inhibition may be an indirect effect.

CONCLUSION

Paclitaxel may be a useful addition to the repertoire of anti-proliferative substances currently in use in glaucoma filtering surgery and shunt implantation. Further studies of the compound and its effects on Tenon's fibroblasts as well as other ocular tissues are warranted.