Corneal melting two weeks after pterygium excision with topical mitomycin C: successfully treated with lamellar keratoplasty and amnion membrane transplantation

Pterygium surgery using inferior rotational conjunctival autograft versus conventional conjunctival autograft with sutures - A comparative study

PURPOSE

To compare the outcomes of pterygium surgery by using an inferior rotational autograft and a conventional superior conjunctival autograft.

METHODS

This was a prospective interventional comparative study of 85 eyes of patients who were divided into two groups of 45 and 40. Standard techniques of both procedures were performed by a single surgeon. Astigmatism, recurrence rates, time taken, and other complications were compared.

RESULTS

All the subjects were in the age group 53 ± 7.56 (40-74) years. Demographic data and type of pterygium were comparable in the two groups. In the rotational group, the preoperative astigmatism was - 2.14 ± 1.36 D, which decreased in 1 week to 1.42 ± 1.11 D, in 1 month to - 1.13 ± 0.99 D, in 3 months to 0.91 ± 0.72 D, and in 6 months to 0.81 ± 0.85 D (P < 0.05 each). Preoperative astigmatism in the conventional group was - 2.63 ± 1.47 D, which decreased to - 1.43 ± 1.04 D in 1 week, -1.18 ± 0.85 D in 1 month, -1.07 ± 0.81 D in 3 months, and - 1.01 ± 0.78 D in 6 months (P < 0.05 each). There was no significant difference between the groups in terms of astigmatism at any follow-up visit (P < 0.05). Complications like dellen, graft edema, and superficial vascularization were seen in both groups. The rotational group had one recurrence (2.86%). No recurrence was noted in the conventional group. None of the complication rates was significantly different between the two groups (P < 0.05).

CONCLUSION

Inferior rotational conjunctival autografting is a good technique for management of pterygium. It has a profile similar to that of conventional conjunctival autograft.

ZD6474 Attenuates Fibrosis and Inhibits Neovascularization in Human Pterygium by Suppressing AKT-mTOR Signaling Pathway

Purpose: To investigate the antifibrotic effect of ZD6474 in human pterygium fibroblasts (HPFs) and angiogenesis in human umbilical vein endothelial cells (HUVECs) compared with mitomycin C (MMC). Methods: Pterygium and tenon fibroblasts were isolated from patients undergoing surgery to culture HPFs and human tenon fibroblasts (HTFs). The effects of ZD6474 on HPF, HTF, and HUVEC proliferation and migration were detected using CCK8 and wound-healing assays, respectively. Fibrosis and epithelial-mesenchymal transformation (EMT) were evaluated by western blotting [transforming growth factor beta (TGF-β)1/2 and snail] and immunofluorescence (vimentin and α-smooth muscle actin). The antiangiogenic effect of ZD6474 on HUVECs was assessed using a tube formation assay. To determine the potential mechanism, the expression of phosphorylated AKT (p-AKT) and phosphorylated mTOR (p-mTOR) was evaluated by treatment with ZD6474 via western blotting. Results: ZD6474 robustly inhibited the proliferation and migration of HPFs rather than HTFs compared with those in the MMC group (**P < 0.01). In HPFs, fibrosis and EMT (vimentin, TGF-β1/2, and snail) were significantly reversed by ZD6474. MMC (>50 μg/mL) significantly reduced HTF viability, whereas ZD6474 (<5 μM/mL) did not decrease HTF viability. HUVEC proliferation and migration were clearly decreased, and tube formation was notably interrupted by ZD6474. Activation of p-AKT and p-mTOR was inhibited by ZD6474 treatment of HPFs and HUVECs. Conclusion: ZD6474 is more effective than MMC in reducing fibrosis and EMT in HPFs. In addition, ZD6474 was less toxic to HTFs. ZD6474 also exhibited antiangiogenic effects in HUVECs. This study may aid in the development of novel agents to prevent pterygium recurrence after pterygium excision.

Inhibitory effects of rosmarinic acid on pterygium epithelial cells through redox imbalance and induction of extrinsic and intrinsic apoptosis

Pterygium is a common tumor-like ocular disease, which may be related to exposure to chronic ultraviolet (UV) radiation. Although the standard treatment for pterygium is surgical intervention, the recurrence rate of pterygium is high when no effective inhibitory drug is used after surgery. Rosmarinic acid (RA) is a polyphenol antioxidant with many biological activities, including anti-UV and anti-tumor properties. This study aimed to examine the inhibitory effects of RA on pterygium epithelial cells (PECs). Methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay was used to examine the cell cytotoxicity of PECs after RA treatment. A fluorescent probe, DCFH-DA (2',7'-dichlorofluorescin diacetate), was stained with PECs to measure intracellular reactive oxygen species (ROS) levels. Antioxidant activity assays were used to measure the levels of superoxide dismutase (SOD) and catalase (CAT) in PECs. Western blot analysis was used to determine the protein expression of nuclear factor E2-related factor 2 (Nrf2), heme oxygenase 1 (HO-1), quinone acceptor oxidoreductase 1 (NQO1), and apoptosis-associated proteins. RA significantly reduced the cell viability of the PECs. Treatment with RA remarkably increased the Nrf2 protein expression levels in the nucleus, HO-1 and NQO1 protein expression levels, and the activities of SOD and CAT. As a result, intracellular ROS levels in PECs were decreased. Additionally, the induction of extrinsic apoptosis on PECs by RA was associated with increasing expressions levels of Fas, Fas-associated protein with death domain (FADD), tumor necrosis factor-alpha (TNF-α), and caspase 8 protein. Moreover, the induction of intrinsic apoptotic cell death in PECs was confirmed through upregulation of cytochrome c, Bax, caspase 9, and caspase 3 and downregulation of Bcl-2 and pro-caspase 3. Our study demonstrated that RA could inhibit the viability of PECs through regulation of extrinsic and intrinsic apoptosis pathways. Therefore, RA may have potential as a therapeutic medication for pterygium.

Antifibrotic effect of pirfenidone on human pterygium fibroblasts

OBJECTIVE

The effects of pirfenidone were investigated on cultured human pterygium fibroblasts (HPFs).

METHODS

HPFs were obtained from pterygium surgery and subjected to primary culture. After treatment with 0.5, 1.0 or 1.5 mg/mL pirfenidone, MTT and cell migration assays were performed, and procollagen secretion and TGF-β expression were measured by Western blotting and immunofluorescence analysis.

RESULTS

Pirfenidone had a significant inhibitory effect on HPF proliferation, migration and collagen synthesis. There were no differences between the cells treated with 0.5, 1.0 and 1.5 mg/mL pirfenidone and the controls in the MTT assay. After 48 h of treatment with 1.0 or 1.5 mg/mL pirfenidone, TGF-β expression was significantly decreased.

CONCLUSIONS

These findings demonstrate that pirfenidone inhibits the proliferation, migration and procollagen secretion of HPFs at nontoxic concentrations by decreasing TGF-β expression. Thus, pirfenidone may be considered as a safe adjuvant for pterygium surgery to prevent recurrence.

The use of antimetabolites as adjunctive therapy in the surgical treatment of pterygium

Background

Pterygium is a proliferative disease with hyperplastic growth of corneoconjunctival fibro vascular tissue onto the cornea. Surgical therapy can be used to successfully manage pterygia; however, recurrence remains a problem. To reduce recurrence, surgical management may include autoconjunctival grafting, lamellar keratoplasty, amniotic membrane transplantation, and intraoperative antimetabolites application.

Purpose

To assess the safety and the efficacy of intraoperative mitomycin C (MMC) and 5-fluorouracil (5-FU) application in preventing recurrence of pterygium after excision.

Patients and methods

The study design is a prospective, randomized clinical trial. A total of 50 patients with bilateral pterygium were recruited for the study. The first group of patients (25) underwent surgical excision of the pterygium with bare sclera in one eye and MMC was applied as adjunctive therapy for the other eye. In the second group 5-FU was used instead of MMC. Recurrences and postoperative complications were measured in the two groups. The mean follow up period of the patients was 18.8 months. Chi square test, odds ratio, and frequency distribution were used to determine significance levels; P-values <0.05 were considered statistically significant.

Results

In group 1 the recurrence rate was 8% for the MMC treated eyes and 32% for their fellow eyes (P = 0.03). In group 2 the rate was 18% for the 5-FU treated eyes and 34% for their fellow eyes (P = 0.07). No serious complications were recorded in either group.

Conclusion

Both MMC and 5-FU reduce the recurrence rate of pterygium after simple surgical excision; statistically, the effect of the former was significant, but insignificant for the latter. Both antimetabolites were safe during the whole study period, but 5-FU recurrent cases showed cosmetically unacceptable appearances with excessive vascularization. MMC, but not 5-FU, is recommended as an adjunctive therapy to prevent recurrence of pterygium after surgical excision.