Modulation of Fibroblasts in Conjunctival Wound Healing

M2 macrophages promote subconjunctival fibrosis through YAP/TAZ signalling

PURPOSE

To evaluate the role of M2 macrophages in subconjunctival fibrosis after silicone implantation (SI) and investigate the underlying mechanisms.

MATERIALS AND METHODS

A model of subconjunctival fibrosis was established by SI surgery in rabbit eyes. M2 distribution and collagen deposition were evaluated by histopathology. The effects of M2 cells on the migration (using wound-scratch assay) and activation (by immunofluorescence and western blotting) of human Tenon's fibroblasts (HTFs) were investigated.

RESULTS

There were more M2 macrophages (CD68+/CD206+ cells) occurring in tissue samples around silicone implant at 2 weeks postoperatively. Dense collagen deposition was observed at 8 weeks after SI. In vitro experiment showed M2 expressed high level of CD206 and transforming growth factor-β1 (TGF-β1). The M2-conditioned medium promoted HTFs migration and the synthesis of collagen I and fibronectin. Meanwhile, M2-conditioned medium increased the protein levels of TGF-β1, TGF-βR II, p-Smad2/3, yes-associated protein (YAP), and transcriptional coactivator with PDZ-binding motif (TAZ). Verteporfin, a YAP inhibitor, suppressedTGF-β1/Smad2/3-YAP/TAZ pathway and attenuated M2-induced extracellular matrix deposition by HTFs.

CONCLUSIONS

TGF-β1/Smad2/3-YAP/TAZ signalling may be involved in M2-induced fibrotic activities in HTFs. M2 plays a key role in promoting subconjunctival fibrosis and can serve as an attractive target for anti-fibrotic therapeutics.

Celastrol alleviates subconjunctival fibrosis induced by silicone implants mimicking glaucoma surgery

Subconjunctival fibrosis is critical to the outcomes of several ophthalmic conditions or procedures, such as glaucoma filtering surgery. This study aimed to investigate the anti-fibrotic effect of celastrol on subconjunctival fibrosis and to further reveal the underlying mechanisms. We used celastrol-loaded nanomicelles hydrogel hybrid as a sustained-release drug. A rabbit model of subconjunctival fibrosis following silicone implantation was used for in vivo study, and TGF-β1-induced human pterygium fibroblast (HPF) activation as an in vitro model. The effects of celastrol on inhibiting TGF-β1-induced migration and proliferation of HPFs were evaluated by scratch wound assay and CCK-8, respectively. Immunofluorescence and western blotting were used to examine the effect of celastrol on the expression of α-SMA, collagen I, fibronectin, and the targets of the Hippo signaling pathway. We found that in vivo celastrol treatment reduced the expression of YAP and TAZ in subconjunctival tissue. Moreover, celastrol alleviated collagen deposition and subconjunctival fibrosis at 8 weeks. No obvious tissue toxicity was observed in the rabbit models. Mechanistically, celastrol significantly inhibited TGF-β1-induced proliferation and migration of HPFs. Pretreatment of HPFs with celastrol also suppressed the TGF-β1-induced protein expression of α-SMA, collagen I, fibronectin, TGF-βRII, phosphorylated Smad2/3, YAP, TAZ, and TEAD1. In conclusion, celastrol effectively prevented subconjunctival fibrosis through inhibiting TGF-β1/Smad2/3-YAP/TAZ pathway. Celastrol could serve as a promising therapy for subconjunctival fibrosis.

Managing the ocular surface after glaucoma filtration surgery: an orphan topic

BACKGROUND

Ocular surface (OS) disorders before glaucoma filtration surgery (GFS) have been considered to play a crucial role influencing the surgical outcome. Conversely, the impact of surgery itself on the OS is almost completely overlooked, though evidence suggest that ocular surface disease (OSD) may be induced in patients by GFS. This review analyzes the determinants involved in the OSD development after GFS, the clinical features and related consequences, the main diagnostic hallmarks, as well as the therapeutic strategies for its management.

METHODS

The PubMed database was utilized for the literature examination. Keywords that were searched included ocular surface disease, glaucoma filtration surgery, filtration bleb, post-surgical management, and quality of life.

RESULTS

After GFS, OSD is promoted by peri- and post-operative factors, such as the filtration bleb (FB) development, combined surgical approach with phacoemulsification, the use of antifibrotic agents and the reintroduction of antiglaucoma medications. This particular form of OSD that present similar clinical features to mild to moderate dry eye, can be named as post-glaucoma surgery-OSD (PGS-OSD). PGS-OSD may negatively affect the FB functionality, thus potentially hindering the disease control, and significantly worsen the patient quality of life (QOL).

CONCLUSIONS

Clinicians are encouraged to routinely include the OS evaluation after GFS and to consider proper management when the occurrence of PGS-OSD worsen the patient's QOL or exert negative effects to the FB functionality. An outline summarizing the main risk factors and the most appropriate therapeutic options to mitigate the PGS-OSD was proposed to support the routine practice.

TGFβ1-Induced Fibrotic Responses of Conjunctival Fibroblasts through the Wnt/β-Catenin/CRYAB Signaling Pathway

Conjunctival fibrosis is a common postoperative complication of glaucoma filtration surgery, resulting in uncontrolled intraocular pressure and surgery failure. Therefore, it is urgent to understand the molecular mechanisms underlying conjunctival fibrosis and to explore novel pharmacologic anti-fibrosis therapies for glaucoma filtration surgery. The 4D-DIA quantitative proteomic results, coupled with experimental data, revealed the activation of the Wnt/β-catenin pathway in transforming growth factor (TGF)-β1-induced human conjunctival fibroblasts (HConFs). Treatment with ICG-001, a Wnt/β-catenin inhibitor, effectively inhibited cell proliferation and migration in TGFβ1-treated HConFs. ICG-001 treatment alleviated the increased generation of extracellular matrix proteins induced by TGFβ1. In addition, ICG-001 reduced the expression level of α smooth muscle actin (α-SMA) and inhibited cell contractility in TGFβ1-treated HConFs. Proteomics data further suggested that αB-crystallin (CRYAB) was a downstream target of Wnt/β-catenin, which was up-regulated by TGFβ1 and down-regulated by ICG-001. Immunoblotting assay also indicated that ICG-001 reduced the expressions of ubiquitin and β-catenin in TGFβ1-treated HConFs, implying that CRYAB stabilized β-catenin by inhibiting its ubiquitination degradation. Exogenous CRYAB promoted cell viability, increased extracellular matrix protein levels, and up-regulated α-SMA expression of HConFs under TGFβ1 stimulation. CRYAB rescued TGFβ1-induced fibrotic responses that were suppressed by ICG-001. In conclusion, this study elucidates the regulatory mechanism of the Wnt/β-catenin/CRYAB pathway in conjunctival fibrosis, offering promising therapeutic targets for mitigating bleb scarring after glaucoma filtration surgery.

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.

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

PURPOSE

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

DESIGN

Retrospective, consecutive, interventional case series.

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Impairment of autophagy promotes human conjunctival fibrosis and pterygium occurrence via enhancing the SQSTM1-NF-κB signaling pathway

Pterygium is a common ocular disease with a high recurrence rate, characterized by hyperplasia of subconjunctival fibrovascular tissue. Autophagy, an important process to maintain cellular homeostasis, participates in the pathogenic fibrosis of different organs. However, the exact role of autophagy in pterygium pathogenesis remains unknown. Here, we found that autophagic activity was decreased in human pterygium tissues compared with adjacent normal conjunctival tissues. The in vitro model of fibrosis was successfully established using human primary conjunctival fibroblasts (ConFB) treated with transforming growth factor-β1 (TGF-β1), evidenced by increased fibrotic level and strong proliferative and invasive capabilities. The autophagic activity was suppressed during TGF-β1- or ultraviolet-induced fibrosis of ConFB. Activating autophagy dramatically retarded the fibrotic progress of ConFB, while blocking autophagy exacerbated this process. Furthermore, SQSTM1, the main cargo receptor of selective autophagy, was found to significantly promote the fibrosis of ConFB through activating the PKCι-NF-κB signaling pathway. Knockdown of SQSTM1, PKCι, or p65 in ConFB delayed TGF-β1-induced fibrosis. Overexpression of SQSTM1 drastically abrogated the inhibitory effect of rapamycin or serum starvation on TGF-β1-induced fibrosis. Collectively, our data suggested that autophagy impairment of human ConFB facilitates fibrosis via activating the SQSTM1-PKCι-NF-κB signaling cascades. This work was contributory to elucidating the mechanism of autophagy underlying pterygium occurrence.

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

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

Noncontact Conjunctiva: A Better Mitomycin C Application Site for Trabeculectomy

INTRODUCTION

Bleb scarring is the most important complication of trabeculectomy. Changing the application position of mitomycin C (MMC) during trabeculectomy might affect the surgery outcome. Our aim is to compare the effectiveness and safety of intraocular pressure (IOP) lowering in two different application sites of mitomycin in trabeculectomy.

METHODS

This retrospective trial compared the surgical outcomes of 177 eyes that underwent trabeculectomy with adjunctive mitomycin C. In 70 eyes, an MMC-soaked sponge was applied under the scleral flap without touching Tenon's capsule. In 107 eyes, an MMC-soaked sponge was applied under the scleral flap covered by Tenon's capsule. Outcome measures were the IOP, best-corrected visual acuity (BCVA), success rates, and incidence of complications.

RESULTS

Within both groups, a highly significant IOP reduction was seen during follow-up. The effectiveness in reducing IOP and the change in best-corrected visual acuity (BCVA) were similar between the two groups. Thin-walled blebs and postoperative hypotony were seen more often when MMC-soaked sponges were applied under the scleral flap covered by Tenon's capsule (P = 0.008 and P = 0.012, respectively). There was no significant difference in BCVA or other complications in either group.

CONCLUSION

Since the effectiveness of IOP reduction was similar between both groups and with a low incidence of thin-walled blebs and hypotony, the subscleral application without touching Tenon's capsule seems to be the safer application site of MMC during trabeculectomy.

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

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

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

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

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

Rational Design of Microfluidic Glaucoma Stent

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

Biomarkers in the Occurrence and Development of Pterygium

Pterygium is a kind of common conjunctival degeneration. The pathogenesis of pterygium is complex, and various biomarkers provide new targets for treatment and prognosis. Currently, the most common treatment for pterygium is surgical excision, but it is invasive risk and has a high recurrence rate. Since the development of sequencing, gene chip technology, and proteomics technologies has been rapid, research on the internal mechanism of disease has been facilitated. This review focuses on recent advances in the discovery of biomarkers from the fields of genetics, proteomics, and epigenetics and their likely functional mechanisms and clinical applications in pterygium.

Atypical U3 snoRNA Suppresses the Process of Pterygium Through Modulating 18S Ribosomal RNA Synthesis

Background

The progression and recurrence of pterygium mainly occur due to the abnormal proliferation and migration of stromal pterygium fibroblasts. This research explores the aberrant expression of small nucleolar RNA U3 (U3 snoRNA) in pterygium and elucidates the molecular mechanisms of U3 snoRNA in pterygium development.

Methods

Primary human conjunctival fibroblasts (HCFs) and human pterygium fibroblasts (HPFs) were separated and cultured from fresh conjunctiva grafts and pterygium tissues. The PLKO.1 lentiviral system and CRISPR/Cas9 recombinant construct were, respectively, used to overexpress and silence U3 snoRNA in HPFs and HCFs for further specific phenotype analysis. RNA-seq and TMT-labeled quantitative protein mass spectrometry were utilized to evaluate the effect of U3 snoRNA on mRNA transcripts and protein synthesis.

Results

Reduced U3 snoRNA in pterygium promotes HCF or HPF cells’ proliferation, migration, and cell cycle but has no significant effect on apoptosis. U3 snoRNA modulates 18S rRNA synthesis through shearing precursor ribosomal RNA 47S rRNA at the 5′ external transcribed spacer (5′ ETS). Moreover, the altered U3 snoRNA causes mRNA and protein differential expression in HCF or HPF cells.

Conclusions

The atypical U3 snoRNA regulates the translation of specific proteins to exert a suppressive function in pterygium through modulating the 18S rRNA synthesis. Here, we uncover a novel insight into U3 snoRNA biology in the development of pterygium.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

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

Corneal Healing and Recovery of Ocular Crystallinity with a Dichloromethane Extract of Sedum dendroideum D.C. in a Novel Murine Model of Ocular Pterygium

Pterygium is a corneal alteration that can cause visual impairment, which has been traditionally treated with the sap of Sedum dendroideum D.C. The pharmacological effect of a dichloromethane extract of S. dendroideum was demonstrated and implemented in a pterygium model on the healing process of corneal damage caused by phorbol esters. In mice of the ICR strain, a corneal lesion was caused by intravitreal injection of tetradecanoylphorbol acetate (TPA). The evolution of the corneal scarring process was monitored with vehicle, dexamethasone, and dichloromethane extract of S. dendroideum treatments by daily ophthalmic administration for fifteen days. The lesions were evaluated in situ with highlighted images of fluorescence of the lesions. Following treatment levels in eyeballs of IL-1α, TNF-α, and IL-10 cytokines were measured. The effective dose of TPA to produce a pterygium-like lesion was determined. The follow-up of the evolution of the scarring process allowed us to define that the treatment with S. dendroideum improved the experimental pterygium and had an immunomodulatory effect by decreasing TNF-α, IL-1α, and maintaining the level of IL-10 expression, without difference with respect to the healthy control. Traditional medical use of S. dendroideum sap to treat pterygium is fully justified by its compound composition.

Inhibitory Effect of Valsartan on Pterygium Fibroblasts

PURPOSE

Angiotensin receptor blockers (ARBs) were shown to have antifibrotic properties in ocular and systemic diseases. In this study, our aim was to investigate the effect of an angiotensin receptor blocker, valsartan, on pterygium fibroblasts and compare this effect with that of mitomycin C (MMC).

METHODS

Pterygium tissue samples were obtained from 3 patients during surgical excision. Primary cultured pterygium fibroblasts and L929 cell cultures were treated with different concentrations of MMC and valsartan.

RESULTS

The cell viability decreased with increasing concentrations of valsartan at 48 hours for both cell types. MMC inhibited the proliferation of both cell types at 48 hours. Both agents significantly decreased the cell migration of the 2 cell types, although it was more prominent in the MMC-treated group.

CONCLUSIONS

Valsartan inhibited the proliferation and migration of pterygium fibroblasts. The known favorable safety profile of these drugs and the results of this study showing inhibitory effect on pterygium fibroblasts make valsartan a potential therapeutic agent for pterygium treatment.

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

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

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

Purpose

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

Methods

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

Results

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

Conclusion

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

The Roles of Various Prostaglandins in Fibrosis: A Review

Organ fibrosis is a common pathological result of various chronic diseases with multiple causes. Fibrosis is characterized by the excessive deposition of extracellular matrix and eventually leads to the destruction of the tissue structure and impaired organ function. Prostaglandins are produced by arachidonic acid through cyclooxygenases and various prostaglandin-specific synthases. Prostaglandins bind to homologous receptors on adjacent tissue cells in an autocrine or paracrine manner and participate in the regulation of a series of physiological or pathological processes, including fibrosis. This review summarizes the properties, synthesis, and degradation of various prostaglandins, as well as the roles of these prostaglandins and their receptors in fibrosis in multiple models to reveal the clinical significance of prostaglandins and their receptors in the treatment of fibrosis.

Controllable release of pirfenidone by polyvinyl alcohol film embedded soft contact lenses in vitro and in vivo

To increase the amount of pirfenidone (PFD) loaded in polyvinyl alcohol (PVA) film embedded soft contact lens (SCL), and evaluate its function of sustaining delivery of drug in vitro and in vivo. Drug loading efficiency within PVA film and SCLs, drug release from SCLs in vitro, and the effects of parameters of SCLs and external environment on drug release in vitro were evaluated by ultraviolet–visible spectrophotometer at 312 nm. Safety of SCLs was evaluated in vitro by transformed human corneal epithelial cell. Safety in vivo was determined by optical coherence tomography and histology of anterior segment of rabbits. Drug release study in tear fluid and aqueous humor were measured by ultra-performance liquid chromatography. SCLs had smooth surface and were fit for experimental rabbits. Amount of PFD in PVA film and SCLs were 153.515 μg ± 12.508 and 127.438 μg ± 19.674, respectively, PFD in PVA film was significantly higher than SCLs (p=.006) and closed to 150 μg (targeting amount of PFD to be loaded). Thickness of SCLs, molecular weight of PVA, and amount of PVA used in SCLs affected drug release in vitro significantly. Thickness of PVA film and amount of drug in SCLs had no effect on drug release rate in vitro. SCLs were safe in vitro and in vivo, PFD released from SCLs could be detected around 12 hours in tears and aqueous humor, and the concentration of drug was higher than eye drop at all detected time points while amount of PFD in SCLs was lower than eye drop. Drug loaded PVA film embedded SCLs may be a promising ocular drug delivery system.

Tryptophan as a Safe Compound in Topical Ophthalmic Medications: In Vitro and In Vivo Studies

Background: To evaluate the effects of tryptophan (TRP) on normal human corneal and conjunctival epithelium in vitro and the re-epithelization of corneal erosion in rabbits.Materials and methods: Corneal epithelial cell (10.014 pRSV-T) and conjunctival epithelial cell (HC0597) cultures were used. The cellular metabolism, viability, secretion of IL-1β, IL-6, IL-10, cytoskeleton organization, transwell migration were determined. Cells were incubated in the presence of TRP at 1-100 μM. After corneal de-epithelization rabbits received TRP drops (100 μM), 5 times a day.Results: TRP increased conjunctival epithelium metabolism at 50 μM and increased the viability of corneal epithelium at 100 μM. TRP (10 μM) enhanced the production of IL-6 by the corneal epithelium and had no effect on IL-1β and IL-10.Conclusions: TRP had no influence on the cellular cytoskeleton but induced a significant pseudopodia projection in both epithelia. TRP did not influence corneal re-epithelization in vivo. TRP was not toxic for corneal and conjunctival epithelia.

[Preoperative management of subconjunctival/sub-Tenon's glaucoma surgery with special consideration of the gel implant (XEN®)]

BACKGROUND

When using subconjunctival/sub-Tenon's ab interno glaucoma surgical procedures, patient selection and preoperative management are essential to reduce postoperative scarring of the bleb.

OBJECTIVE

The aim of this study was to compile a list of risk factors that may have an unfavorable effect on the scarring process.

METHOD

A literature search was carried out in PubMed with respect to the scarring process of the gel implant XEN®.

RESULTS

Ophthalmological risk factors for conjunctivoscleral/Tenon's wound healing process include dry eye, allergies, use of eye drops containing preservatives and previous eye surgery.

CONCLUSION

The preoperative administration of artificial tear substitutes, corticosteroids and the fundamental change to preservative-free eye drops can support the normalization of a chronic inflammatory altered conjunctiva and thus positively influence the wound healing process after surgery.

Extracellular vesicle-based therapeutics for the regeneration of chronic wounds: current knowledge and future perspectives

Chronic wounds are still an intractable medical problem for both clinicians and researchers and cause a substantial social and medical burden. Current clinical approaches can only manage wounds but have limited capacity to promote the regeneration of chronic wounds. As a type of natural nanovesicle, extracellular vesicles (EVs) from multiple cell types (e.g., stem cells, immune cells, and skin cells) have been shown to participate in all stages of skin wound healing including inflammation, proliferation, and remodeling, and display beneficial roles in promoting wound repair. Moreover, EVs can be further re-engineered with genetic/chemical or scaffold material-based strategies for enhanced skin regeneration. In this review, we provide an overview of EV biology and discuss the current findings regarding the roles of EVs in chronic wound healing, particularly in immune regulation, cell proliferation and migration, angiogenesis, and extracellular matrix remodeling, as well as the therapeutic effects of EVs on chronic wounds by genetic modification, in combination with functionalized biomaterials, and as drug carriers. We also discuss the challenges and perspectives of translating EV-based therapies into clinical wound care in the future.

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

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

Niacin Metal-Organic Framework-Laden Self-Healing Hydrogel for Wound Healing

Bacterial infection is one of the most significant impediments to wound healing. To treat wounds, non-biological and non-pharmacological interventions have gained increasing importance as they are easily translatable into clinical products. In this study, we developed a niacin metal-organic frameworks (NOFs)-laden hybrid hydrogel with self-healing ability for better wound healing. The copper based-NOFs (Cu-NOFs) and zinc based-NOFs (Zn-NOFs) were constructed and encapsulated into the self-healing hydrogels, which could prevent NOFs from directly interacting with protein-containing solutions (e. g., tissue fluid). The hydrogel was prepared by using four-armed benzaldehyde-terminated polyethylene glycol (BAPEG) and carboxymethyl chitosan (CMC). Our results showed that the hydrogel gained self-healing ability through reversible Schiff base reaction. In addition, after loading NOFs, the hybrid hydrogel exerted significant effects on antibacterial and antioxidant activities. The in vivo studies demonstrated that the hybrid hydrogel could alleviate inflammation and enhance the formation of granulation tissue, collagen and vascular tissue, thereby promoting wound closure in rats with E. coli -infected wounds. Overall, this study highlights the tremendous potential for the clinical implementation of NOFs-laden hydrogel with good self-healing, antibacterial and antioxidant properties in wound healing.

Sulforaphane modulates TGFβ2-induced conjunctival fibroblasts activation and fibrosis by inhibiting PI3K/Akt signaling

AIM

To examine the effects of sulforaphane on fibrotic changes of transforming growth factor (TGFβ2) induced human conjunctival fibroblast (HConFs).

METHODS

HConFs were cultured and divided into control, TGFβ2 (1 ng/mL), sulforaphane and TGFβ2+sulforaphane groups. Cell viability and apoptosis were detected using the MTT and ApoTox-Glo Triplex assay. Cell migration was detected using scratch and Transwell assay. Real-time quantitative PCR method was used to evaluate mRNA expression of TGFβ2, matrix metalloproteinase-2 (MMP2), myosin light chain kinase (MYLK), integrin αV, integrin α5, fibronectin 1 and α-smooth muscle actin (α-SMA). The protein expression of α-SMA, p-PI3K, PI3K, p-Akt, and Akt were detected by Western blot.

RESULTS

The proliferation of HConFs was significantly (P<0.05) suppressed by sulforaphane compared to control cells with the increase of the concentration and treatment time. Cell proliferation after 48h incubation was significantly reduced with 100 µmol/L sulforaphane treatment by 17.53% (P<0.05). The Transwell assay showed sulforaphane decreased cell migration by 18.73% compared with TGFβ2-induced HConF (P<0.05). TGFβ2-induced the increasing expression of fibronectin, type I collagen and α-SMA, and the phosphorylation of PI3K and Akt were all significantly suppressed by sulforaphane pretreatment.

CONCLUSION

Sulforaphane inhibits proliferation, migration, and synthesis of the extracellular matrix in HConFs, and inhibiting the PI3K/Akt signaling pathway. Sulforaphane could be a potential therapeutic drug for prevention of scar formation in filtering bleb after trabeculectomy.

The Expression and Role of Hypoxia-induced Factor-1α in Human Tenon's Capsule Fibroblasts under Hypoxia

PURPOSE

To determine the expression of hypoxia-induced factor-1α (HIF-1α) and its downstream factors in human Tenon's capsule fibroblasts (HTFs) and changes in HTFs biological functions, we explored the role of HIF-1α in HTFs under hypoxia to provide a basis for studying the regulation of HIF-1α in wound healing after glaucoma surgery.

MATERIALS AND METHODS

we established HTFs hypoxia model in vitro, meanwhile the HIF-1α agonist VH298 or inhibitor KC7F2 was added to HTFs, and the normoxia group was used as a control. Western blot, immunofluorescence and ELISA were used to detect the expression of HIF-1α, vascular endothelial growth factor (VEGF), transforming growth factor-β (TGF-β), Smads and collagen I. The proliferation of HTFs was quantified by cell counting kit-8, and cell migration was tested by healing scratch test.

RESULTS

HIF-1α protein expression increased under hypoxia, peaked from 4-24 h, and then decreased. The secretion of VEGF and TGF-β increased with prolonged hypoxia time. VH298 and KC7F2 upregulated and downregulated the levels of VEGF and TGF-β, respectively, suggesting that HIF-1α upregulates and downregulates the levels of VEGF and TGF-β in HTFs under hypoxia, respectively. HIF-1α upregulated the proliferation, migration and collagen synthesis of HTFs under hypoxia.

CONCLUSIONS

Regulating HIF-1α and its downstream factors effectively regulated HTFs proliferation, migration and collagen synthesis. HIF-1α is a promising regulator in the study of wound healing after glaucoma surgery.

Anti-fibrosis potential of pirarubicin via inducing apoptotic and autophagic cell death in rabbit conjunctiva

This study investigated the potential efficacy of pirarubicin (THP) in modulating rabbit conjunctival fibrosis both in vitro and in vivo and characterized the underlying mechanisms. Primary rabbit conjunctival fibroblasts (RCF) were cultured and treated with THP or mitomycin C (MMC) for 5 min, followed by assaying for cell viability, cell cycle distribution, apoptotic and autophagic pathways. The production of reactive oxygen species (ROS) and chemotaxis of macrophages by RCF were evaluated using 2',7'-dichlorofluorescein diacetate (DCFH-DA) labeling and transwell migration assay, respectively. Limbal stem cell excision in combination with alkali burn was performed on the rabbits to establish a model of limbal deficiency and conjunctival fibro-vascular invasion. After three months, the modeled fibro-vascular tissue was excised combined with topical subconjunctival 5-min exposure to THP compared with MMC intraoperatively. The recurrence of postoperative fibrosis and the expression of apoptosis, autophagy, and inflammation markers were evaluated by immunohistochemistry. All modeled rabbits developed conjunctival fibro-vascular lesions, which were similar to human recurrent pterygium (HRP). Both THP and MMC inhibited RCF proliferation and arrested cell cycle at the G0/G1 phase. In particular, 7.5 μmol/L THP remarkably promoted RCF autophagy by upregulating the levels of Beclin 1, Atg 5/12 conjugate, and LC3B, whereas, 15 μmol/L THP significantly triggered a cascade of mitochondrial-associated RCF apoptosis. THP induced the production of ROS and enhanced the chemoattraction of macrophages by RCF. Similar to 600 μmol/L MMC, both 7.5 μmol/L and 15 μmol/L THP attenuated postoperative conjunctival fibrosis in the models; 7.5 μmol/L THP preferentially enhanced autophagy while causing fewer side effects. THP exerted its antifibrotic action by modulating autophagy in RCF, inducing cell cycle arrest, and mitochondrial-mediated apoptosis. THP at the dose of 7.5 μmol/L prevented postoperative conjunctival fibrosis in an animal model.

[Medicated prevention of scarring after glaucoma surgery]

Modulation of wound healing is one of the main challenges in glaucoma surgery. Modern antiproliferative agents used to reduce postoperative scarring are either insufficiently effective or inadequate in terms of safety. In the search for novel agents devoid of such drawbacks, specialists directed their attention to selective inhibitors of proinflammatory cytokines and growth factors. The article reviews pathophysiologic basis of wound healing, characteristics of inflammatory mediators affecting fibroblast proliferation and scarring, and provides description of the currently used and new, potentially promising antiproliferative agents.

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.

Eye Drops of Metformin Prevents Fibrosis After Glaucoma Filtration Surgery in Rats via Activating AMPK/Nrf2 Signaling Pathway

Metformin has effective therapeutic effects in anti-tumor and anti-fibrotic diseases. However, how the antifibrotic effect of metformin in the eye and how it is transferred are still unclear. Here, the eye drop of metformin treatment was studied in Sprague–Dawley (SD) rats of glaucoma filtrating surgery (GFS). Rats were administered randomly bilateral drops: control group (without surgery), GFS group, metformin group or mitomycin C (MMC) group (sponge application intraoperatively, 0.02%). Bleb features and intraocular pressure (IOP) were assessed for postoperative week 4. Metformin effectively inhibited fibrosis and improved the surgical outcomes of GFS. In vitro, we found that the degree of oxidative stress and fibrosis in metformin pretreated-Human Conjunctival Fibroblasts (HConFs) were reduced; the pro-fibrotic response of HConFs were decreased by inducing macrophagic polarity changes. Besides, the inhibition of nuclear factor erythroid 2-related factor 2 (Nrf2)/AMP-activated protein kinase (AMPK) and the competition of organic cation transporters (OCTs) effectively reduced the anti-fibrotic capability of metformin. Together, this experiment indicates that metformin enters into HConFs cell with OCTs, which can protect against filtrating blebs scar formation in SD rats of GFS via activating AMPK/Nrf2 axis and the downregulation of profibrogenic and inflammatory biomarkers.

A Comparison of Subconjunctival Wound Healing between Different Methods of Dissecting Subconjunctival Tissues

OBJECTIVE

To compare different methods for dissecting subconjunctival tissues by developing subconjunctival wound healing models.

METHODS

New Zealand white rabbits were separated into 3 groups based on the method by which the rabbit subconjunctival wound healing model was generated: subconjunctival tissues were dissected episclerally (EPI) or subepithelially (SUB), with a corresponding blank control (CON). All the cases in the experimental groups were surgically prepared with conjunctival flaps, and they were sacrificed on the third postoperative day. At the surgical sites, the protein levels of hypoxia-inducible factor-1 (HIF-1)-α, vascular endothelial growth factor (VEGF)-A, and matrix metalloproteinase (MMP)-2 were detected by Western blot, morphological vascularity was measured by Adobe Photoshop, and subconjunctival fibrosis was assessed by histology.

RESULTS

Compared with the CON group, both the EPI and SUB groups showed significantly upregulated protein levels of HIF-1α, VEGF-A, and MMP-2. In addition, the protein levels of HIF-1α, VEGF-A, and MMP-2 were higher in the EPI group than in the SUB group. Morphological vascularity was significantly elevated in the EPI group compared with the SUB and CON groups. Collagen content was markedly increased in the EPI group compared with the SUB and CON groups.

CONCLUSIONS

Dissecting subconjunctival tissues subepithelially inhibits subconjunctival fibrosis, which may be instructive in tenonectomy in filtration surgery.

Plasma Rich in Growth Factors for the Treatment of Cicatrizing Conjunctivitis

Purpose

The objective was to evaluate the clinical results obtained from the use of immunosafe plasma rich in growth factors (isPRGF) in the treatment of patients with cicatrizing conjunctivitis (CC) who had not responded to the usual therapy.

Patients and Methods

This is a retrospective study that included patients diagnosed with CC, in whom isPRGF was used in different phases (I: eye drops; II: eye drops and injectable; III: eye drops, injectable and surgical treatment) to achieve control of the inflammation. As a clinical follow-up of the patients, the better corrected visual acuity (BCVA), degree of inflammation (measured from 1 to 4), the severity of the CC, Schirmer I test, IOP and TBUT were analyzed. The adverse events were also evaluated.

Results

Ten eyes (6 patients) were evaluated, 50% corresponded to Stevens–Johnson Syndrome and 50% to ocular mucous membrane pemphigoid. The mean age was 59.7 ± 16.5 (39–80) years, and 50% were women. Fifty per cent of the cases were initially considered severe CC, and 10% of the cases (one eye of one patient) were considered severe CC at the end of the treatment (p = 0.046). The initial degree of inflammation was 2 in 4 eyes, 3 in two eyes, and 4 in 4 eyes, and final inflammation degree was 1 in all cases (p = 0.004). Twenty per cent of the cases achieved stability in Phase I of the treatment with immunosafe PRGF, 70% with both Phases I and II, and only one case underwent Phase III to achieve stability. The IOP improved significantly (p = 0.027) though the BCVA, TBUT and Schirmer I test showed no significant changes. The follow-up time was 23.1 ± 6.7 (13.6–30.3) months. No adverse effects were reported.

Conclusion

Treatment with PRGF technology in its injectable and topical immunosafe formulations may be a novel alternative for the treatment of patients with CC, given its complement activity modulating effect, as well as its anti-inflammatory, antifibrotic and regenerative properties.

The TβR II-targeted aptamer S58 prevents fibrosis after glaucoma filtration surgery

Glaucoma filtration surgery (GFS) is an effective clinical treatment for glaucoma when intraocular pressure (IOP) control is poor. However, the occurrence of conjunctival scarring at the surgical site is the main reason for failure of the surgery. In a previous study, we isolated and developed S58, a novel nucleic acid aptamer targeting TβR II, by systematic evolution of ligands by exponential enrichment (SELEX). Here, we show how S58 sterically inhibits the TβR II interaction with TGF-β. The effects of topical S58 treatment were studied in a rabbit model of GFS. At 6 postoperative weeks, S58 reduced fibrosis and prolonged bleb survival in rabbits after GFS. Further in vitro tests showed that the levels of fibrosis in S58 treated-Human Conjunctival Fibroblasts (HConFs) were decreased and that antioxidant defense was increased. In addition, the loss of nuclear factor erythroid 2-related factor 2 (Nrf2) or the inhibition of phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) reversed the anti-fibrotic effects of S58. The present work suggests that S58 could effectively improve GFS surgical outcomes by activating the intracellular antioxidant defense PI3K/Akt/Nrf2 signaling pathway.

DNA methylation of miR-200 clusters promotes epithelial to mesenchymal transition in human conjunctival epithelial cells

Epithelial to mesenchymal transition (EMT) contributes to fibrosis associated pathologies including scarring of different ocular tissues. Recently targeting EMT is seen as an appropriate therapeutic approach for different fibrosis related eye diseases such as macular degeneration or glaucoma surgery related fibrosis. Nevertheless, for ocular surface diseases, target genes specific for particular cell type or condition are still undefined. This study aimed to expose the complex regulatory mechanisms that trigger EMT in human conjunctival epithelial (HCjE) cells. EMT was induced by prolonged treatment with two TGF-β isoforms, TGF-β1 and TGF-β2, and their combination. TGF-β1 showed the strongest potential for initiating EMT in HCjE cells, reflected on morphological changes, cell migration and the levels of mRNA expression of different epithelial (CDH1, OCLN, DSP) and mesenchymal (CDH2, FN1, VIM, SNAI1, ZEB2, TWIST1) marker genes. Co-treatment with the DNA demethylating agent 5-Azacytidine (5-AzaC) was capable of stopping the transition of HCjE cells towards a mesenchymal phenotype, based on morphological features, reduced cell mobility and mRNA and protein expression levels of epithelial and mesenchymal marker genes. An EMT qRT-PCR-based array revealed that EMT induced considerable alterations in gene expression, with downregulation of the majority of epithelial marker genes and upregulation of genes specific for the mesenchymal state. The major effect of 5-AzaC treatment was observed as a suppression of mesenchymal marker genes, suggesting the involvement of upstream negative regulator(s) whose promoter demethylation and subsequent expression will in turn promote EMT switch off. The expression level of miRNAs potentially important for EMT induction was determined using qRT-PCR-based array which pointed at members of miR-200 family as main regulators of EMT process in HCjE cells. 5-AzaC treatment induced increased expression of miR-200a, -200b, -200c and miR-141 towards the control level, indicating important role of DNA methylation in their regulation. The DNA methylation status of both miR-200 family clusters, analyzed with high-resolution melting (HRM) and bisulfite sequencing (Bis-Seq), revealed that TGF-β1-induced EMT was accompanied by increase in promoter CpG methylation of both miR-200 loci, which was reverted after 5-AzaC treatment. In conclusion, our results indicate that DNA demethylation of promoters of miR-200 loci is critically important for stopping and reverting the EMT in human conjunctival epithelial cells, suggesting the potential for the development of novel epigenetic-based therapeutic strategies for treating conjunctival conditions associated with EMT.

Local delivery of corticosteroids in clinical ophthalmology: A review

Locally administered steroids have a long history in ophthalmology for the treatment of inflammatory conditions. Anterior segment conditions tend to be treated with topical steroids whilst posterior segment conditions generally require periocular, intravitreal or systemic administration for penetration. Over recent decades, the clinical applications of periocular steroid delivery have expanded to a wide range of conditions including macular oedema from retino-vascular conditions. Formulations have been developed with the aim to provide practical, targeted, longer-term and more efficacious therapy whilst minimizing side effects. Herein, we provide a comprehensive overview of the types of periocular steroid delivery, their clinical applications in ophthalmology and their side effects.

[Monocentric, Retrospective, Comparative Study of the Safety and Effectiveness of Wound Modulation with Bevacizumab after Combined Cataract Surgery with Implantation of the CyPass Stent]

BACKGROUND

Because of the known positive effect of bevacizumab (Avastin^®) on wound modulation in trabeculectomy, a retrospective study evaluated the safety and efficacy of wound modulation with Avastin following combined cataract surgery with CyPass stent.

METHOD

Retrospectively, the pre-, intra- and postoperative data (after three and six months) were collected from 484 eyes after combined surgery (n = 187 without Avastin, n = 297 with Avastin). The safety criteria were intraoperative complications and postoperative slit-lamp microscopic findings. Efficacy criteria were intraocular pressure (IOP) and number of IOP-lowering drugs.

RESULTS

With respect to age and sex distribution, early postoperative fibrin reaction, intraocular pressure and reduction in medication, the two groups (with and without Avastin) did not differ statistically significantly. However, iris tissue reactions were statistically significantly more frequently observed three months postoperatively in the control group than in the Avastin group (chi square test: p = 0.02, n = 47/128); there is a slight trend after six months towards less iris tissue reaction in the Avastin group (chi square test: p = 0.15, n = 45/125). Other trends in favour of the Avastin group were identified within the failure rate (2% compared to 6% at three months (chi square test: p = 0.103, n = 50/130) and 4 to 10% at six months (chi square test: p = 0.106, n = 50/130) and within the proportion of eyes without supplemental hypotensive medication, with 86 vs. 74% and 68 vs. 56% (chi square test: three months: p = 0.053; six months: p = 0.12; n = 50/130). In addition, 85% of the eyes in the Avastin group reached the postoperative pressure threshold of ≤ 21 mmHg without supplemental hypotensive medication three months postoperatively and 65% after six months compared to 74% (chi square test: p = 0.099, n = 50/130) and 54% (chi square test: p = 0.11, n = 50/130) in the control group.

CONCLUSION

The postoperative injection of Avastin into the anterior chamber is safe, reduces iris tissue reactions and improves efficacy up to six months postoperatively to a clinically limited extent.

Targeting platelet-derived growth factor receptor β inhibits the proliferation and motility of human pterygial fibroblasts

Background: Pterygium, a common eye disease with high postoperative recurrence, lacks effective therapeutic strategies. Therefore, it's urgent to identify specific targets to develop rationally targeted molecular drugs for the pterygial therapy. Methods: The cell proliferation and motility were studied in both the primary human pterygial fibroblasts (hPFs) and an ex vivo pterygium model. hPFs transfected with the pCMV3-PDGFRB plasmid, PDGFRB siRNA and CRISPR/Cas9 system were used to determine the role of PDGFR-β in pterygial fibroblasts functions. Western blotting, immunohistochemistry and immunofluorescence were performed to evaluate the expression of the key proteins. Results: PDGFR-β expression in the pterygial stroma and primary hPFs was significantly higher than that in the conjunctiva and human conjunctival fibroblasts. PDGF-BB promoted the proliferation, migration and invasion of hPFs, which can be significantly suppressed by sunitinib via inhibition of the PDGFR-β/extracellular signal-regulated kinase (ERK) pathway. In the ex vivo model, the knockout of PDGFRB and sunitinib treatment blocked the proliferation and motility of fibroblasts in the pterygial stroma via the suppression of PDGFR-β/ERK pathway. Conclusion: This study demonstrates that PDGFR-β may be a potential therapeutic target for pterygium, and inhibition of PDGFR-β by sunitinib is a promising and effective approach for pterygium treatment.

The ocular surface after successful glaucoma filtration surgery: a clinical, in vivo confocal microscopy, and immune-cytology study

We investigated the ocular surface (OS) system modifications after completely successful glaucoma surgery in thirty-eight patients undergoing trabeculectomy (surgical group), using laser scanning confocal microscopy (LSCM) and impression cytology (IC). Twenty-six medically controlled glaucomatous patients served as controls (medical group). LSCM, IC, and the ocular surface disease index (OSDI) and National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25) questionnaires, were performed at baseline and after six months. The main outcomes were: goblet cell density (GCD), limbal dendritic cell density (LDCD), subbasal corneal nerve inhomogeneity (SCNI), Meibomian gland density and inhomogeneity (MGD, MGI), and HLA-DR positivity. There were no significant baseline differences between groups. At the sixth month, the surgical group showed a GCD increase (p < 0.001), and a LDCD, SCNI, MGI, HLA-DR (p < 0.001), OSDI and NEI VFQ-25 scores decrease (p < 0.05). The medical group did not show significant OS modifications, showing LSCM and IC parameters significantly worse compared to the surgical group (p < 0.001). The OSDI score correlated with GCD, MGI, SCNI, LDCD, and HLA-DR (p < 0.001; p < 0.05; p < 0.01). The present study found that the whole OS system objectively improved after completely successful glaucoma filtration surgery. These changes positively affected the OSDI score, but not the NEI VFQ-25 score.

Differential effects of dexamethasone and indomethacin on Tenon's capsule fibroblasts: Implications for glaucoma surgery

Dysregulated wound healing and subsequent fibrosis represents the most common cause of failure in glaucoma filtration surgery. Primary means to prevent this outcome are the anti-metabolite surgical adjuvants, however, topical corticosteroids are commonly used postoperatively to permit further control of wound healing and development of the filtration bleb. Unfortunately, they carry important side effects such as raised intraocular pressure, cataract and increased infection risk. Non-steroidal anti-inflammatory drugs (NSAIDs) show promising results in clinical trials as an alternative wound modulatory drug. NSAIDs exhibit non-inferiority to steroids in terms of post-operative intraocular pressure control and secondary IOP lowering interventions, however there is little known about the differing effects these drugs exert on human Tenon's capsule fibroblast (HTCF) mediated wound healing. The purpose of this study was to assess the individual effects of dexamethasone and indomethacin on the extracellular matrix modifying actions of HTCFs in vitro. To this end, HTCFs were cultured in 3D collagen matrices as well as in 2D monolayers and exposed to clinically relevant concentrations of dexamethasone or indomethacin for up to seven days. HTCF-mediated wound healing functions were assayed through collagen matrix contraction, extracellular matrix morphology, estimation of HCTF proliferation and differentiation into myofibroblasts within the collagen matrices, as well as western blot. Both drugs significantly reduced HTCF-mediated collagen contraction relative to control however there was a significant trend towards greater inhibition with indomethacin exposure compared to dexamethasone. Indomethacin exposure significantly reduced HTCF-mediated collagen remodelling activity compared vehicle control, whereas dexamethasone was unable to reduce remodelling activity at any of the studied exposures. Both drugs reduced myofibroblast differentiation, however indomethacin alone demonstrated an inhibitory effect on final cell number relative to control whereas dexamethasone had no significant effect at any studied exposure. These findings demonstrate that both steroidal and NSAID treatment can mitigate HTCF-mediated collagen contraction and αSMA expression. However, NSAIDs may function to better impede HTCF proliferation and remodelling activity. Taken in the context of previous glaucoma surgical trials, NSAIDs appear to be a viable alternative to steroids for post-operative wound modulation.