The Pro-Fibrotic Behavior of Human Tenon's Capsule Fibroblasts in Medically Treated Glaucoma Patients

Genome-wide RNA sequencing of ocular fibroblasts from glaucomatous and normal eyes: Implications for glaucoma management

Primary open angle glaucoma is a leading cause of visual impairment and blindness which is commonly treated with drugs or laser but may require surgery. Tenon's ocular fibroblasts are involved in wound-healing after glaucoma filtration surgery and may compromise a favourable outcome of glaucoma surgery by contributing to fibrosis. To investigate changes in gene expression and key pathways contributing to the glaucomatous state we performed genome-wide RNA sequencing. Human Tenon's ocular fibroblasts were cultured from normal and glaucomatous human donors undergoing eye surgery (n = 12). mRNA was extracted and RNA-Seq performed on the Illumina platform. Differentially expressed genes were identified using a bioinformatics pipeline consisting of FastQC, STAR, FeatureCounts and edgeR. Changes in biological functions and pathways were determined using Enrichr and clustered using Cytoscape. A total of 5817 genes were differentially expressed between Tenon's ocular fibroblasts from normal versus glaucomatous eyes. Enrichment analysis showed 787 significantly different biological functions and pathways which were clustered into 176 clusters. Tenon's ocular fibroblasts from glaucomatous eyes showed signs of fibrosis with fibroblast to myofibroblast transdifferentiation and associated changes in mitochondrial fission, remodeling of the extracellular matrix, proliferation, unfolded protein response, inflammation and apoptosis which may relate to the pathogenesis of glaucoma or the detrimental effects of topical glaucoma therapies. Altered gene expression in glaucomatous Tenon's ocular fibroblasts may contribute to an unfavourable outcome of glaucoma filtration surgery. This work presents a genome-wide transcriptome of glaucomatous versus normal Tenon's ocular fibroblasts which may identify genes or pathways of therapeutic value to improve surgical outcomes.

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.

Ab Externo SIBS Microshunt with Mitomycin C for Open-Angle Glaucoma: Three-Year Results as a Primary Surgical Intervention

PURPOSE

To determine the effectiveness, risk factors for surgical failure, and adverse events in a large cohort of patients receiving stand-alone ab externo poly(styrene-block-isobutylene-block-styrene) (SIBS) microshunt implantation with mitomycin C (MMC) over 3 years of follow-up.

DESIGN

Retrospective, interventional case series.

PARTICIPANTS

Glaucomatous eyes on maximally tolerated medical therapy with no previous subconjunctival glaucoma surgery.

METHODS

Records of eyes that underwent ab externo SIBS microshunt with MMC between July 2015 and November 2017 were reviewed. Data from all follow-up visits were utilized and included intraocular pressure (IOP), medication use, postoperative interventions, complications, and reoperations.

MAIN OUTCOME MEASURES

The primary outcome was proportion of eyes at 3 years with (1) no 2 consecutive IOPs > 17 mmHg (or < 6 mmHg with > 2 lines of vision loss from baseline); (2) ≥ 20% reduction from baseline IOP; and (3) using no glaucoma medications (complete success). Secondary outcomes included 14 and 21 mmHg upper IOP thresholds with and without ≥ 20% IOP reduction from baseline, qualified success (with glaucoma medications), risk factors for failure, median IOP/medications, postoperative interventions, complications, and reoperations.

RESULTS

One hundred fifty-two eyes from 135 patients were included. Complete and qualified success was achieved in 55.6% and 74.8% of eyes, respectively. Time to first glaucoma medication use was a median of 16.9 (interquartile range [IQR], 12.1-34.1) months; however, 59.4% of eyes remained medication free at 3 years. Significant risk factors for failure included receiving < 0.4 mg/ml of MMC (adjusted hazard ratio [HR], 2.42; 95% confidence interval [CI], 1.44-4.05) and baseline IOP < 21 mmHg (adjusted HR, 1.79; 95% CI, 1.03-3.13). The most common complications were choroidal detachment, hyphema, and anterior chamber shallowing, occurring in 7%, 5%, and 5% of eyes, respectively. The needling rate was 15.1%, with significantly higher frequency for baseline IOP > 21 mmHg (HR, 3.21; 95% CI, 1.38-7.48). Revisions occurred in 7% of eyes and reoperations in 2.6%. Eyes receiving < 0.4 mg/ml of MMC underwent more revisions (odds ratio, 4.9; 95% CI, 1.3-18.3).

CONCLUSIONS

Three-year follow-up data from this large cohort continues to support promising rates of qualified and complete success, with decreased medication burden postoperatively and few postoperative complications and interventions. Comparisons to other filtering surgeries will further facilitate integration of the SIBS microshunt into the surgical treatment paradigm.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Salivary Exosomes in Health and Disease: Future Prospects in the Eye

Exosomes are a group of vesicles that package and transport DNA, RNA, proteins, and lipids to recipient cells. They can be derived from blood, saliva, urine, and/or other biological tissues. Their impact on several diseases, such as neurodegenerative, autoimmune, and ocular diseases, have been reported, but not fully unraveled. The exosomes that are derived from saliva are less studied, but offer significant advantages over exosomes from other sources, due to their accessibility and ease of collection. Thus, their role in the pathophysiology of diseases is largely unknown. In the context of ocular diseases, salivary exosomes have been under-utilized, thus creating an enormous gap in the literature. The current review discusses the state of exosomes research on systemic and ocular diseases and highlights the role and potential of salivary exosomes as future ocular therapeutic vehicles.

ALK5 Inhibition of Subconjunctival Scarring From Glaucoma Surgery: Effects of SB-431542 Compared to Mitomycin C in Human Tenon's Capsule Fibroblasts

Purpose

The gold standard for managing postoperative ocular fibrosis in glaucoma surgery is the chemotherapeutic mitomycin C (MMC) despite its association with significant adverse effects. This study compares in vitro the antifibrotic efficacy and cytotoxicity of the small-molecule TGFβ1 inhibitor SB-431542 (SB) to MMC.

Methods

To measure collagen contraction, human Tenon's capsule fibroblasts (HTCFs) embedded in a three-dimensional collagen lattice were exposed to 0.2 mg/mL MMC or 20 µM SB followed by incubation with 2 ng/mL TGFβ1. Total protein extracted from experimentally treated HTCFs underwent immunoblotting for α-smooth muscle actin (α-SMA), matrix metallopeptidase 9 (MMP-9), and EDA splice-variant fibronectin (EDA-FN) expression. Cytotoxicity and cell metabolism were assessed using LIVE/DEAD staining, lactate dehydrogenase (LDH) assay, and methylthiazole tetrazolium (MTT) assay.

Results

Collagen lattice contraction in TGFβ1-induced HTCFs was significantly lowered by SB and MMC. Pretreatment with SB and MMC significantly lowered protein expression of α-SMA, MMP-9, and EDA-FN in HTCFs relative to TGFβ1 alone. HTCF viability in collagen lattices was significantly reduced with MMC pretreatment but not SB pretreatment. MMC-pretreated HTCFs had a significant increase in LDH release after 3 hours and a decrease in MTT activity after 20 minutes, while SB-pretreated HTCFs showed no significant changes via MTT or LDH assay during the same treatment period.

Conclusions

SB shows comparable efficacy to MMC in reducing expression of fibrosis-promoting proteins in HTCFs and in vitro scarring activity. SB distinguishes itself from MMC by exhibiting less cytotoxicity in both two-dimensional and three-dimensional in vitro assays.

Translational Relevance

This study demonstrates in vitro the potential of SB as a safer alternative ocular antifibrotic agent.

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

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

Zinc Oxide Tetrapods Modulate Wound Healing and Cytokine Release In Vitro—A New Antiproliferative Substance in Glaucoma Filtering Surgery

Glaucoma filtering surgery is applied to reduce intraocular pressure (IOP) in cases of uncontrolled glaucoma. However, postoperative fibrosis reduces the long-term success of both standard trabeculectomy and microstents. The aim of this study was to test the antiproliferative and anti-inflammatory potential of ZnO-tetrapods (ZnO-T) on human Tenon’s fibroblasts (HTFs) for glaucoma surgery. The toxicity of ZnO-T on HTFs was determined using an MTT test. For analysis of fibroblast proliferation, migration, and transdifferentiation, cultures were stained for Ki67, alpha-smooth muscle actin (α-SMA), and p-SMAD. A fully quantitative multiplex ELISA was used to determine the concentrations of different cytokines, platelet-derived growth factor (PDGF), and hepatocyte growth factor (HGF) in culture supernatants with and without previous ZnO-T treatment. Treatment with higher concentrations (10 and 20 µg/mL) was associated with HTF toxicity, as shown in the wound healing assay. Furthermore, the number of Ki67, α-SMA-positive, and pSMAD-positive cells, as well as IL-6 and HGF in supernatants, were significantly reduced following incubation with ZnO-T. In conclusion, we were able to show the antiproliferative and anti-inflammatory potentials of ZnO-T. Therefore, the use of ZnO-T may provide a new approach to reducing postoperative fibrosis in glaucoma filtering surgery.

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.

Elucidating the Therapeutic Potential of Cell-Penetrating Peptides in Human Tenon Fibroblast Cells

Cell-penetrating peptides (CPPs) have been widely used as vehicles for delivering therapeutic molecules to the site of action. Apart from their delivering potential, the biological effects of CPPs have not been explored in detail. JTS-1 is a CPP that has been reported to have gene delivery functions, although its biological role is yet to be determined. Hence, in this study, we revealed the biological mechanism such as its uptake mechanism and immunogenic potential and function using primary human tenon fibroblast (TF) cells collected from patients undergoing glaucoma trabeculectomy surgery. Our results showed that the JTS-1 peptide has an α-helical structure and is nontoxic up to 1 μM concentration. It was found to be colocalized with early endosome (Rab5), recycling endosome (Rab7), and Rab11 and interacted with major histocompatibility complex (MHC) class I and II. The peptide also affected actin polymerization, which is regulated by cofilin phosphorylation and ROCK1 localization. It also inhibited TF cell proliferation. Therefore, the JTS-1 peptide could be used as a possible therapeutic agent for modifying the fibrosis process, where TF proliferation is a key cause of surgery failure.

LINC01605 knockdown induces apoptosis in human Tenon's capsule fibroblasts by inhibiting autophagy

Glaucoma is an irreversible disease that causes blindness. Formation of a hypertrophic scar (HS) is the main cause of failure of glaucoma surgery. The long non-coding RNA LINC01605 is closely associated with the formation of HS; however, the function of LINC01605 in the formation and development of HS remains unclear. For this study, firstly, human Tenon's capsule fibroblasts (HTFs) and corneal epithelial cells (control cells) were collected from patients (n=5) with POAG who underwent glaucoma filtration surgery at Fuyang People's Hospital. Immunofluorescence analysis was performed to detect the expression levels of vimentin (one of the main components of medium fiber and plays an important role in the cytoskeleton and motility), keratin (the main component of cytoskeletal proteins) and LC3 (an autophagy marker). In addition, reverse transcription-quantitative PCR analysis was performed to detect LINC01605 expression. Besides, the Cell Counting Kit-8 assay was performed to assess the viability of human Tenon's capsule fibroblasts (HTFs). Next, flow cytometry was performed to detect HTF apoptosis. Furthermore, western blot analysis was performed for Bax, Bcl-2, Pro-caspase-3, cleaved caspase-3, phosphorylated (p-)Smad2, Smad2, α-SMA, MMP9, ATG7, p62, beclin 1, p-AMPK and AMPK in HTFs to determine the mechanism by which LINC01605 regulates the formation and development of HS. Moreover, a Transwell assay was performed to detect the migratory ability of HTFs. The results demonstrated that LINC01605 was significantly upregulated in HS tissues compared with that in normal (control/healthy) tissues. In addition, vimentin was highly expressed in HTFs, whereas keratin was expressed at a low level. Also, in HTFs, LINC01605 knockdown inhibited cell viability by inducing apoptosis, decreasing Smad2 activation and inhibiting autophagy. Furthermore, LINC01605 knockdown significantly inhibited the migratory ability of HTFs. Transfection with LINC01605 small interference RNAs significantly downregulated the expression levels of p-Smad2, α-SMA and MMP9 in HTFs. Furthermore, LINC01605 knockdown notably inhibited the viability and migration, and induced the apoptosis of HTFs, the effects of which were reversed following treatment with TGF-β. Taken together, the results of the present study suggested that LINC01605 knockdown may inhibit the viability of HTFs by inducing the apoptotic pathway. These findings may provide novel directions for the treatment of HS.

Dihydroartemisinin Inhibits TGF-β-Induced Fibrosis in Human Tenon Fibroblasts via Inducing Autophagy

Background

The formation of hypertrophic scars (HS) can result in the failure of glaucoma surgery, and fibrosis is known to be closely associated with the progression of HS. Dihydroartemisinin (DHA) has been reported to inhibit the progression of fibrosis; however, whether DHA can alleviate the formation of HS remains unclear.

Methods

In the present study, in order to examine the effects of DHA on the progression of HS, human Tenon's capsule fibroblasts (HTFs) were isolated from patients who underwent glaucoma surgery. In addition, Western blot analysis, microtubule associated protein 1 light chain 3 α staining and reverse transcription-quantitative PCR were performed to detect protein and mRNA expression levels in the HTFs, respectively. Cell proliferation was detected by Ki67 staining. Flow cytometry was used to examine apoptosis and reactive oxygen species (ROS) levels in the HTFs.

Results

The results revealed that TGF-β promoted the proliferation and fibrosis of HTFs; however, DHA significantly reversed the effects of TGF-β by increasing cell autophagy. In addition, DHA notably induced the apoptosis of TGF-β-stimulated HTFs by increasing the ROS levels, while these increases were partially reversed by 3-methyladenine. Furthermore, DHA notably increased the expression of microRNA (miR)-145-5p in HTFs in a dose-dependent manner.

Conclusion

The present study demonstrated that DHA inhibits the TGF-β-induced fibrosis of HTFs by inducing autophagy. These findings may aid in the development of novel agents for the prevention of the formation of HS following glaucoma surgery.

[Rho kinase inhibitors as new local therapy option in primary open angle glaucoma]

BACKGROUND

In 2014 in Japan and 2017 in the USA, the Rho-kinase inhibitors were approved as a new antiglaucomatous substance group and will now be launched in Europe.

OBJECTIVE

On this occasion the current state of knowledge on Rho-kinase inhibitors is presented.

METHODS

In intensive search in PubMed the relevant experimental and clinical literature on the Rho-kinase inhibitors ripasudil and netarsudil and the combination of netarsudil and latanoprost were selected and compiled for this review.

RESULTS

The intraocular pressure lowering efficacy of ripasudil and netarsudil is in the range of the beta blocker timolol and the prostaglandin analogue latanoprost. In the fixed combination netarsudil/latanoprost the intraocular pressure reduction is greater than that of the single components and reaches a target pressure of below 15 mm Hg in 32%. Conjunctival hyperemia with 53-65% is the most common local side effect. Systemic side effects are very rare and so far there are no contraindications.

CONCLUSION

The Rho-kinase inhibitors are an interesting new introduction for glaucoma therapy, as each new pressure-lowering therapy represents an additional chance to reach the individually defined target pressure level in a glaucoma patient with local therapy; however, many of the pleiotropic effects associated with Rho-kinase inhibitors have so far only been found experimentally and will require clinical confirmation in the future.