Antifibrotic role of low-dose mitomycin-c-induced cellular senescence in trabeculectomy models

Use of Myriocin as co-adjuvant in glaucoma surgery: An in vitro study

Mitomycin C as well as other antiproliferative drugs are off-label agents widely used to prevent the failure of glaucoma surgery due to activation of Tenon's fibroblasts and the ensuing excessive subconjunctival scarring. Though efficacious, these treatments are associated with some severe long-term complications, so it is crucial to investigate less cytotoxic compounds as adjuvant therapy in glaucoma surgery. The aim of this study was to evaluate the effect and potential cytotoxicity of Myriocin, a natural sphingolipid synthesis inhibitor, on TGF-β1-induced myofibroblasts transformation of human dermal fibroblasts. We found that myriocin significantly attenuated the transcript levels of αSMA, CTGF, and MMP9 which are involved in the fibrosis process. Mitomycin C poorly affects the same pro-fibrotic markers while reducing fibroblasts motility as much as myriocin. At similar doses, five minutes of mitomycin C treatment consistently affects human dermal fibroblast viability and proliferation compared to prolonged myriocin application, strengthening already published data on the good tolerability of this natural compound. Our results draw attention to the use of myriocin as an adjuvant in glaucoma surgery due to the effectiveness in reducing fibroblasts to myofibroblasts transformation and the low cytotoxicity.

Efficacy and safety of intraoperative injection of mitomycin C during trabeculectomy: a systematic review and meta-analysis

PURPOSE

Trabeculectomy, a primary surgical treatment for glaucoma, often employs mitomycin C (MMC) to reduce scar formation and improve surgical outcomes. However, the optimal application method of MMC, whether by injection or sponge, remains a subject of debate. This meta-analysis aims to compare injectable and sponge-based MMC application in terms of efficacy and safety, focusing on various clinical outcomes in glaucoma patients.

METHODS

A comprehensive literature search of Scopus, MEDLINE, EMBASE, Ovid, Chinese biomedical literature database, China National Knowledge Infrastructure, and Cochrane Library was done for eligible studies that report data of glaucoma patients who were administered MMC by injection or sponge application during trabeculectomy. Outcomes of interest included intraocular pressure (IOP) reduction, bleb appearance grading (height, extent, vascularity), use of anti-glaucoma medications, and rates of complete success, qualified success, and failure. Data were reported as weighted mean differences (WMD) or odds ratios (OR) with confidence intervals (CI). The random-effects inverse-variance model with DerSimonian-Laird estimate of tau2 was employed, with continuity correction applied where necessary.

RESULTS

A total of 15 studies with 1276 participants were included. The meta-analysis revealed no significant difference in IOP reduction between patients treated by MMC injection and sponge application (WMD = - 0.434). Significant differences were observed in bleb appearance grading scores for height (WMD = - 0.170) and extent (WMD = 0.174), with substantial heterogeneity. The use of anti-glaucoma medications was significantly lower in the injection group (WMD = - 0.274). However, there were no significant differences in the rates of complete success, qualified success, and failure. The study demonstrated moderate to high heterogeneity across various outcomes.

CONCLUSION

This meta-analysis indicated that while both injection and sponge methods of MMC application during trabeculectomy were equally effective for IOP reduction, they differ in their impact on bleb morphology and postoperative medication requirement. The findings highlight the need for individualized treatment approaches in glaucoma surgery, taking into account the specific needs and characteristics of each patient.

Challenges in Managing Secondary Glaucoma Post-Repeat Penetrating Keratoplasty in a Developing Country

Purpose

To illustrate the complexity in managing secondary glaucoma post-repeat penetrating keratoplasty in a developing country.

Case Description

A patient with a history of five repeat penetrating keratoplasties (PKPs) showed good intraocular pressure (IOP) control with trabeculectomy; however, blebitis occurred as an undesirable complication. Trabeculectomy was done rather than tube implantation due to socioeconomic factors, although it's not an ideal treatment. After the infection subsided, we performed a bleb revision with a scleral patch graft. Intraocular pressure was high in the follow-up period after the scleral patch, therefore we decided to do tube implantation. Following glaucoma tube implant surgery, the patient had good IOP control and a clear graft after six months of follow-up.

Conclusion

Secondary glaucoma post repeat PKPs is challenging in both diagnosis and management. Immediate action is imperative to control IOP, prevent glaucoma progression, and minimize corneal graft damage. In addition to medical reasons, socioeconomic factors should be considered.

Protective effect of human amniotic membrane extract against hydrogen peroxide-induced oxidative damage in human dermal fibroblasts

OBJECTIVE

One of the main approaches to preventing skin ageing is to protect fibroblast cells from oxidative stress. The promoting effect of the human amniotic membrane extract (hAME) on re-epithelization, proliferation and migration of cells in wound healing has been already well studied. This experimental study aimed to investigate the antioxidant activity of hAME against hydrogen peroxide (H₂ O₂ )-induced dermal fibroblast damage.

METHODS

Here, to establish the ageing model, human foreskin fibroblasts (HFFs) were exposed to 200 μM H₂ O₂ for 2 h. HFFs were treated with 0.1 mg/ml AME for 24 or 48 h before or/and after H₂ O₂ exposure. A total of 48 h following the H₂ O₂ treatment, we measured cell proliferation, viability, senescence-associated β-galactosidase (SA-β-Gal), antioxidants and preinflammatory cytokine (IL-6) levels, as well as the expression of senescence-associated genes (P53 and P21).

RESULTS

The obtained results indicated that under oxidative stress, AME significantly increased cellular viability and not only promoted the cell proliferation rate but also attenuated apoptotic induction condition (p < 0.001). AME also significantly reversed the SA-β-Gal levels induced by H₂ O₂ (p < 0.001). Additionally, both pre- and post-treatment regimen by AME down-regulated the expression of senescence marker genes (p < 0.001). Moreover, AME declined different oxidative stress biomarkers such as superoxide dismutase and catalase and increased the glutathione amount.

CONCLUSION

Altogether, our results indicated that AME had a remarkable antioxidant and antiageing activity as pre- and post-treatment regimen, pointing to this compound as a potential natural-based cosmeceutical agent to prevent and treat skin ageing conditions.

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.