Recurrent pterygium: A review

Evaluation of the clinical efficacy of modified LSC transplantation plus BCL implantation in the treatment of pterygium

OBJECTIVE

To explore the clinical efficacy of modified limbal stem cell transplantation(Modified LSC transplantation) and bandage contact lens(BCL) implantation in pterygium surgery.

METHODS

A total of 479 patients with primary pterygium who were admitted to our hospital from March 2019 to March 2023 were randomly divided into three groups: the normal group (Group A: 89 patients), the control group (Group B: 195 patients), and the modified group (Group C: 195 patients). Each group received different intervention measures. Group A did not undergo surgical treatment and were required to follow up as outpatients. Group B received LSC transplantation combined with interrupted suturing plus BCL, whereas Group C received modified LSC transplantation combined with BCL. The degree of corneal irritation symptoms, wound healing and graft status under slit lamp, incidence and recurrence rate of complications, tear film rupture time, tear secretion test, intraocular pressure, ocular surface inflammation response(IL-1β, PGE2, TNF-α, VEGF), and visual quality were compared and analyzed at various time points after surgery.

RESULTS

Compared with those in the Group B, patients in the Group C experienced faster normalization of corneal epithelium recovery, fewer corneal irritation symptoms, and better wound healing. The break-up time (BUT) of the tear film at 1 week to 1 year postoperatively was significantly greater in the Group C than Group B, with values approaching those of Group A by 3 months (P < 0.05). The Schirmer test results revealed a similar trend to that of the BUT. Further analysis of intraocular pressure (IOP) at different time points revealed no significant differences among the three groups at postoperative Day 1. However, due to the use of corticosteroid eye drops postoperatively, IOP was greater in both the Group B(17.24 ± 2.12 mmHg) and Group C (17.02 ± 2.37 mmHg) than Group A (13.92 ± 1.57 mmHg) at 1 week. By 1 month, Group C had a lower IOP (15.77 ± 1.63 mmHg) than Group B(17.78 ± 2.41 mmHg). There were no significant differences in IOP among the three groups from 3 months to 1 year (P > 0.05). The ELISA results indicated that the expression levels of the ocular surface inflammatory factors IL-1β, TNF-α, PEG2, and VEGF in the Group C were lower than those in Group B from 1 week to 1 year post surgery. Under both natural light and low-light conditions (spatial frequency/6 cd), Group C had better best-corrected visual acuity and contrast sensitivity than Group B at 1 week to 1 year postoperatively. Additionally, Group C had lower corneal higher-order aberrations (including astigmatism, spherical aberrations, and total higher-order aberrations) and superior vision-related quality of life scores at 1 year postoperatively than Group B, with statistically significant differences (P < 0.05).

CONCLUSION

Modified LSC transplantation combined with BCL implantation provided superior treatment outcomes for patients with pterygium, which was worthy of further clinical promotion.

Comparison of postoperative topical interferon-α2b versus intraoperative mitomycin C for pterygium recurrence prevention: a randomized clinical trial

PURPOSE

To evaluate the effect of postoperative interferon-alpha 2b (IFN-α2b) ophthalmic drops versus intraoperative mitomycin-c (MMC) on preventing pterygium recurrence.

METHODS

This prospective randomized clinical trial was conducted on patients who were candidates for pterygium surgery. A total of 75 patients were included in the study from December 2021 to December 2022, of which 64 patients (one eye each) were examined and analyzed based on the inclusion criteria. Then the patients were randomly assigned to control groups, intra-operative MMC (32 patients) and the intervention group, IFN-α2b drops after the operation (32 patients). All patients underwent pterygium surgery using the rotational conjunctival flap method.

RESULTS

In terms of pterygium grading, 8 (12.5%), 25 (39.06%), and 31 (48.44%) eyes were in grades 1, 2, and 3, respectively. The average size of the pterygium was 3.6 ± 0.7 mm. The grade and size of pterygium had the same distribution in the two groups. There was no statistically significant difference between the two groups in the level of post-operative clinical inflammation. The present study showed no significant difference in complications between the two groups (p = 0.999). The recurrence rate in the control group was 9.4% (3 eyes), and 0% (no recurrence) in the intervention group (p = 0.119).

CONCLUSIONS

interferon-alpha 2b group did not show a statistically significant difference in preventing pterygium recurrence compared to the mitomycin C group. The post-surgery administration of IFN-α 2b drops can effectively prevent pterygium recurrence with a comparable and even more compelling effect than MMC during surgery.

Key Clinical and Histopathological Features of a Pterygium-Like Induced Lesion in a Rabbit Model

Purpose

Surgery is the definitive treatment for pterygium; therefore, reliable animal models are required for translational research. The goal of this investigation was to establish a standardized preclinical model of pterygium-like lesion.

Methods

A subconjunctival injection of fibroblasts (NIH3T3) and extracellular matrix was administered to 22 New Zealand rabbits. Clinical evaluation was assessed at different points, the severity of the lesion was scored according to four grades and correlated with the area of hyperemia and the histopathological findings on day 23.

Results

Thirteen of 22 eyes (60%) developed pterygium-like lesions after 7 days and progressed through different grades. Initially, grade 3, characterized by an elevated and fleshiness conjunctiva with tortuous hyperemia, was evident on day 7. By day 15, lesion decreased to grade 2, with less elevation and hyperemia. Subsequent improvement was noted, with grade 1 on day 18. Finally, day 23 was marked by a white‒yellow lesion, classified as grade 4. The area of hyperemia increased from grade 2 to grade 3 (P < 0.05) and decreased from grade 3 to grade 4 (P ≤ 0.05). Histopathological analysis revealed a tendency toward increasing inflammation at grades 2, 3, and 4. There was a correlation between clinical features and the degree of inflammation.

Conclusions

Subconjunctival injection of NIH3T3 and extracellular matrix induces a pterygium-like lesion that progresses across four grades, beginning with an acute inflammatory process that evolve a chronic form. This study provides a replicable model for simulating pterygium.

Translational Relevance

The development of a standardized preclinical model of pterygium to evaluate new pharmacological or surgical treatments.

Comparing Intracanalicular and Topical Steroid Use in Patients Undergoing Pterygium Surgery

OBJECTIVE

The study received funding from Ocular Therapeutix, Inc., Bedford, MA.We undertook this study to compare the efficacy of intracanalicular dexamethasone 0.4 mg with topical prednisolone acetate (PA) 1% in controlling postoperative pain and inflammation in patients undergoing pterygium surgery.

METHODS

This was an open-label, prospective, interventional, nonrandomized comparative trial. Thirty patients were assigned to one of the following groups: Group A [intracanalicular insert of 0.4 mg dexamethasone placed into upper and lower puncta during the procedure, followed by at postoperative month 1 visit institution of topical PA 1% twice daily × 2 weeks then once daily × 2 weeks] or Group B [nonintervention group with institution on postoperative day 1 topical PA 1% every 2 hours × 2 weeks then four times per day × 2 weeks then twice daily × 2 weeks then once daily × 2 weeks].

RESULTS

Fifteen cases and 15 controls were enrolled. There was no statistical difference in patient-reported pain or satisfaction between the case and control groups at 1 day; 1 week; and 1, 3, and 6 months postoperatively. There was no significant difference in time to an ocular hyperemia score of 0 between the two groups. There was no difference in the rate of corneal reepithelialization and recurrence rate (two controls). Nine eyes had transient ocular hypertension (seven cases and two controls).

CONCLUSION

Intracanalicular dexamethasone 0.4 mg may reduce the medication burden for patients who need prolonged postoperative steroid therapy as is routine in the setting of pterygium surgery. It is a safe and effective alternative to PA 1% drops alone for postoperative control of pain and inflammation in pterygium surgery.

Contribution of Matrix Metalloproteinase-2 Genotypes to Taiwan Pterygium Risk

BACKGROUND/AIM

In the literature, the studies about the role of matrix metalloproteinase-2 (MMP-2) in pterygium diagnosis are mainly based on its protein expression. The role of MMP-2 variants has never been examined. The aim of this study was to examine the association of MMP-2 genotypes with pterygium risk.

MATERIALS AND METHODS

MMP-2 rs243865 and rs2285053 were genotyped in 140 pterygium cases and 280 non-pterygium controls by typical polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) genotyping technology.

RESULTS

The genotypic frequency of MMP-2 rs243865 CC, CT and TT were 86.4%, 12.9% and 0.7% in the pterygium group and 81.1%, 17.1% and 1.8% in the non-pterygium group (p for trend=0.3389). The variant CT and TT carriers had a 0.70- and 0.38-fold pterygium risk (95%CI=0.39-1.26 and 0.04-3.25, p=0.2982 and 0.6686, respectively). As for MMP-2 rs2285053, the genotypic frequency of CC, CT and TT were 67.1%, 28.6% and 4.3% in the pterygium group, non-significantly different from those in non-pterygium group (p for trend=0.7081). The CT and TT carriers had a 0.88- and 0.71-fold pterygium risk (95%CI=0.56-1.38 and 0.27-1.88, p=0.6612 and 0.6456, respectively). The allelic analysis results showed that MMP-2 rs243865 variant T allele was not associated with pterygium risk (7.1% versus 10.4%, OR=0.67, 95%CI=0.39-1.13, p=0.1649). As for MMP-2 rs2285053, the T allele was not associated with pterygium risk either (18.6% versus 21.1%, OR=0.85, 95%CI=0.59-1.23, p=0.4136).

CONCLUSION

The genotypes at MMP-2 rs243865 or rs2285053 played minor role in determining individual susceptibility for pterygium among Taiwanese.

The efficacy and safety of continuous blanket suture for severe recurrent pterygium with symblepharon

Background

Managing recurrent pterygium combined with symblepharon presents significant challenges in ophthalmology. Clinicians aim to reconstruct the ocular surface, alleviate eye movement restrictions, and minimize recurrence risks.

Objective

Evaluation of efficacy and safety of continuous blanket sutures (CBS) for fixation of large autologous conjunctival grafts in patients with severe recurrent pterygium with symblepharon.

Methods

Retrospective, observational case series. Thirty-nine patients (40 eyes) were included, all with severe recurrent pterygium with symblepharon. During surgery, CBS was employed to affix large autologous conjunctival grafts to the exposed sclera, aiming to restore the ocular surface to smoothness as much as possible. All patients were followed up for more than one year. Main outcome measures include the rate of recurrence, improvement of eye movement, and intraoperative and postoperative complications.

Results

Nearly all patients exhibited a smooth ocular surface and largely restored physiological structures during the follow-up period. There were no graft loss or contraction cases until the last follow-up, with only three eyes experiencing a pterygium recurrence (recurrence rate 7.5%, 3/40). Preoperative eye movement limitations improved significantly from 2.10 ± 0.71 (range 1-3) to 0.33 ± 0.53 (range 0-2; p < 0.001) post-surgery. Other postoperative complications included varying degrees of corneal scarring and a single instance of conjunctival granulomatous hyperplasia (1 eye, 2.5%).

Conclusion

When addressing severe recurrent pterygium with Symblepharon, using CBS to secure large autologous conjunctival grafts during surgery can achieve favorable postoperative outcomes. This surgical method is safe and feasible and effectively rebuilds a smooth ocular surface, improves the appearance of the ocular surface, and reduces the recurrence rate of pterygium after excision.

Surgical Management of Bilateral Limbal Stem Cell Deficiency

At the age of 43 years-old, a man was left with bilateral limbal stem cell deficiency after an ocular alkaline burn with lime, which resulted in corneal opacification. After multiple unsuccessful surgical attempts to restore vision, including penetrating keratoplasties and Boston keratoprosthesis, visual acuity was counting fingers in the left eye. At 73 years of age, the patient underwent another surgery in his left eye. Cauterization of neovessels and removal of the vascular pannus were followed by partial excision of Tenon's capsule. Penetrating keratoplasty was followed by an intrastromal injection of anti-VEGF (vascular endothelial growth factor), and the ocular surface was covered with amniotic membrane. Postoperatively, the graft was clear with no signs of inflammation; vision improved to 20/50 and remained stable throughout the following two years. Herein we describe some adjunctive procedures that might have delayed failure and rejection of the corneal graft. This case demonstrates the difficulties in treating bilateral limbal stem cell deficiency in a tertiary eye care center with no capacity to perform stem cell therapy.

Modified Limbal-Conjunctival Autograft Surgical Technique: Long-Term Results of Recurrence and Complications

PURPOSE

The aim of this study was to report the recurrence and complication rates of a modified limbal-conjunctival autograft surgical technique for pterygium excision.

METHODS

This was a retrospective, single-surgeon, single-operating environment, consecutive case series of 176 eyes in 163 patients with a biopsy-proven diagnosis of pterygium. All patients underwent excision using a 23-gauge needle to "behead" the pterygium head, followed by a limbal-conjunctival autograft including ∼50% of the palisades of Vogt. Outcomes measured included recurrence, defined as any conjunctival fibrovascular growth, and complication rates. Correlations between preoperative patient characteristics, pterygium morphology, and intraoperative factors (width of corneal extension, conjunctival defect, and graft) with postoperative recurrence were examined using logistic regression models.

RESULTS

The median age was 59.5 years and 122 eyes (69.3%) had primary pterygium (type I: 17%, II: 37.5%, and III: 45.5%). Kaplan-Meier analysis demonstrated the median pterygium-free follow-up period to be 723 days (range 46-7230 days). Recurrence was observed in 3 eyes of 2 patients (1.7%). No postoperative graft-related complications were observed. Postoperative symptomatology was transient. Age demonstrated a negative correlation with recurrence (odds ratio 0.888, 95% CI, 0.789-0.998, P = 0.046). However, no other correlations with preoperative or intraoperative factors, including whether pterygium was primary or recurrent, were identified (all P > 0.05).

CONCLUSIONS

This modified limbal-conjunctival autograft technique represents an effective alternative that offers a very low recurrence rate and avoids extensive dissection or antimetabolites, with minimal complications and transient postoperative symptomatology, over a long-term follow-up period. This technique is relatively simple and successful for both primary and recurrent pterygia. Future comparative studies with other surgical techniques may determine which are superior.

Up-to-date molecular medicine strategies for management of ocular surface neovascularization

Ocular surface neovascularization and its resulting pathological changes significantly alter corneal refraction and obstruct the light path to the retina, and hence is a major cause of vision loss. Various factors such as infection, irritation, trauma, dry eye, and ocular surface surgery trigger neovascularization via angiogenesis and lymphangiogenesis dependent on VEGF-related and alternative mechanisms. Recent advances in antiangiogenic drugs, nanotechnology, gene therapy, surgical equipment and techniques, animal models, and drug delivery strategies have provided a range of novel therapeutic options for the treatment of ocular surface neovascularization. In this review article, we comprehensively discuss the etiology and mechanisms of corneal neovascularization and other types of ocular surface neovascularization, as well as emerging animal models and drug delivery strategies that facilitate its management.

Artificial intelligence assisted pterygium diagnosis: current status and perspectives

Pterygium is a prevalent ocular disease that can cause discomfort and vision impairment. Early and accurate diagnosis is essential for effective management. Recently, artificial intelligence (AI) has shown promising potential in assisting clinicians with pterygium diagnosis. This paper provides an overview of AI-assisted pterygium diagnosis, including the AI techniques used such as machine learning, deep learning, and computer vision. Furthermore, recent studies that have evaluated the diagnostic performance of AI-based systems for pterygium detection, classification and segmentation were summarized. The advantages and limitations of AI-assisted pterygium diagnosis and discuss potential future developments in this field were also analyzed. The review aims to provide insights into the current state-of-the-art of AI and its potential applications in pterygium diagnosis, which may facilitate the development of more efficient and accurate diagnostic tools for this common ocular disease.

Evaluating the application of argon laser on pterygium surgery: Report of 30 patients

BACKGROUND

The recurrence rate plays a key role in using various treatments of pterygium. This study assessed the effectiveness of argon laser therapy before the excision of pterygium on the recurrence rate.

MATERIALS AND METHODS

The eyes (n = 60) of patients (n = 30) were divided into two groups based on the treatment. All eyes had undergone pterygium excision with the bare sclera technique. Three weeks before surgery, an argon laser was applied to 30 eyes. Patients have been followed up for 1 year, and the progression of pterygium has been evaluated at days 1, 7, 14, and 30, and then, every 2 months until month 6 and then every 3 months until month 12. Recurrence was defined as more than 1 mm growth of pterygium from the limbus.

RESULTS

In the group with adjuvant argon laser therapy, the mean size of pterygium was 3.7 ± 0.47 mm before surgery and 2.3 ± 0.98 after 12 months (P = 0.001). These were 3.8 ± 0.43 mm and 2.4 ± 1 mm in the other group (P = 0.001). The recurrence of the pterygium was 76% (23/30) in the group treated with an argon laser and 90% (27/30) in another group (P = 0.16). There was no correlation between pterygium sizes before surgery and the pterygium recurrence rate in both eyes (P = 0.272 [right] and 0.916 [left]).

CONCLUSION

Argon laser therapy on pterygium before surgery cannot decrease its recurrence rate, but its application gives a good vision and clarifies the surgery's target area.

Ocular-Surface Regeneration Therapies for Eye Disorders: The State of the Art

The ocular surface is a complex structure that includes cornea, conjunctiva, limbus, and tear film, and is critical for maintaining visual function. When the ocular-surface integrity is altered by a disease, conventional therapies usually rely on topical drops or tissue replacement with more invasive procedures, such as corneal transplants. However, in the last years, regeneration therapies have emerged as a promising approach to repair the damaged ocular surface by stimulating cell proliferation and restoring the eye homeostasis and function. This article reviews the different strategies employed in ocular-surface regeneration, including cell-based therapies, growth-factor-based therapies, and tissue-engineering approaches. Dry eye and neurotrophic keratopathy diseases can be treated with nerve-growth factors to stimulate the limbal stem-cell proliferation and the corneal nerve regeneration, whereas conjunctival autograft or amniotic membrane are used in subjects with corneal limbus dysfunction, such as limbal stem-cell deficiency or pterygium. Further, new therapies are available for patients with corneal endothelium diseases to promote the expansion and migration of cells without the need of corneal keratoplasty. Finally, gene therapy is a promising new frontier of regeneration medicine that can modify the gene expression and, potentially, restore the corneal transparency by reducing fibrosis and neovascularization, as well as by stimulating stem-cell proliferation and tissue regeneration.

Efficacy and safety of anti-vascular endothelial growth factor agents in the treatment of primary pterygium

Purpose

To further evaluate the efficacy and safety of anti-vascular endothelial growth factor (VEGF) agents in management of primary pterygium.

Methods

Randomized controlled trials (RCTs) in databases of PubMed, Web of Science, Embase, and the Cochrane Central Register of Controlled Trials were searched from inception to September 2022. Recurrences and complications were evaluated as the pooled risk ratio (RR) and 95% confidence interval (CI) using random-effects model.

Results

In total of 1,096 eyes in 19 RCTs were included. Anti-VEGF agents statistically decreased recurrence rate of pterygium following surgery (RR 0.47, 95% CI 0.31-0.74, P < 0.001). Subgroup analysis showed that anti-VEGF as an adjunct to bare sclera (RR 0.34, 95% CI 0.13-0.90, P = 0.03) and conjunctival autograft (RR 0.50, 95% CI 0.26-0.96, P = 0.04) statistically reduced recurrence rate, while the effect was not favorable for conjunctivo-limbo autograft (RR 0.99, 95% CI 0.36-2.68, P = 0.98). Anti-VEGF agents statistically decreased recurrence in White patients (RR 0.48, 95% CI 0.28-0.83, P = 0.008), while didn't in Yellow patients (RR 0.43, 95% CI 0.12-1.47, P = 0.18). Both topical (RR 0.19, 95% CI 0.08-0.45, P < 0.001) and subconjunctival anti-VEGF agents (RR 0.64, 95% CI 0.45-0.91, P = 0.01) had a positive influence on recurrence. There was no statistically significant difference in complications between the groups (RR 0.80, 95% CI 0.52-1.22, P = 0.29).

Conclusions

As adjuvant treatment, anti-VEGF agents statistically reduced the recurrence following pterygium surgery, especially among White patients. Anti-VEGF agents were well tolerated without increased complications.

Uncovering the role of transient receptor potential channels in pterygium: a machine learning approach

OBJECTIVES

We aimed at identifying the role of transient receptor potential (TRP) channels in pterygium.

METHODS

Based on microarray data GSE83627 and GSE2513, differentially expressed genes (DEGs) were screened and 20 hub genes were selected. After gene correlation analysis, 5 TRP-related genes were obtained and functional analyses of gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were performed. Multifactor regulatory network including mRNA, microRNAs (miRNAs) and transcription factors (TFs) was constructed. The 5 gene TRP signature for pterygium was validated by multiple machine learning (ML) programs including support vector classifiers (SVC), random forest (RF), and k-nearest neighbors (KNN). Additionally, we outlined the immune microenvironment and analyzed the candidate drugs. Finally, in vitro experiments were performed using human conjunctival epithelial cells (CjECs) to confirm the bioinformatics results.

RESULTS

Five TRP-related genes (MCOLN1, MCOLN3, TRPM3, TRPM6, and TRPM8) were validated by ML algorithms. Functional analyses revealed the participation of lysosome and TRP-regulated inflammatory pathways. A comprehensive immune infiltration landscape and TFs-miRNAs-mRNAs network was studied, which indicated several therapeutic targets (LEF1 and hsa-miR-455-3p). Through correlation analysis, MCOLN3 was proposed as the most promising immune-related biomarker. In vitro experiments further verified the reliability of our in silico results and demonstrated that the 5 TRP-related genes could influence the proliferation and proinflammatory signaling in conjunctival tissue contributing to the pathogenesis of pterygium.

CONCLUSIONS

Our study suggested that TRP channels played an essential role in the pathogenesis of pterygium. The identified pivotal biomarkers (especially MCOLN3) and pathways provide novel directions for future mechanistic and therapeutic studies for pterygium.

Amniotic membrane transplantation and conjunctival autograft combined with mitomycin C for the management of primary pterygium: A systematic review and meta-analysis

Background

Pterygium is a common ocular surface disease. Recurrence is the greatest concern in the treatment of pterygium. Thus, a standardized and effective treatment modality with minimal risk for complications is needed for the management of pterygium. The aim of this systematic review and meta-analysis was to evaluate different tissue grafting options, including conjunctival autograft (CAG) with mitomycin C (MMC), CAG alone, and amniotic membrane transplantation (AMT), for the management of primary pterygium.

Methods

We searched the MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials databases for relevant studies. We included randomized controlled trials (RCTs) in which CAG + MMC and AMT were compared with surgical excision with CAG alone for the treatment of primary pterygium. The rates of recurrence and adverse events reported in the studies were also evaluated. Risk ratio (RR) was used to represent dichotomous outcomes. The data were pooled using the inverse variance weighting method. The quality of the evidence derived from the analysis was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Risk of bias was assessed using the revised Cochrane risk-of-bias tool for randomized trials.

Results

Twelve RCTs (n = 1144) were deemed eligible and included for analysis. Five RCTs had a low risk of bias, five had some concerns, and two had a high risk of bias. Subgroup analysis showed a statistically significant reduction in the rate of pterygium recurrence after CAG + MMC (RR = 0.12; 95% confidence interval [CI], 0.02–0.63). This outcome was rated as high-quality evidence according to the GRADE criteria. There were insignificant differences between the rates of recurrence after AMT and CAG (RR = 1.51; 95% CI, 0.63–3.65). However, this result was rated as low-quality evidence. Regarding adverse events, patients treated using AMT showed significantly lower rates of adverse events than those treated using CAG (RR = 0.46; 95% CI, 0.22–0.95). However, this finding was rated as low-quality evidence as well. CAG + MMC showed a safety profile comparable to that of surgical excision with CAG alone (RR = 1.81; 95% CI, 0.40–8.31). This result was also rated as low-quality evidence.

Conclusion

A single intraoperative topical application of 0.02% MMC during excision of pterygium followed by CAG has significantly shown to decrease the rate of pterygium recurrence to 1.4% with no severe complications.

Expression profiling suggests the involvement of hormone-related, metabolic, and Wnt signaling pathways in pterygium progression

BACKGROUND

Pterygium is an ocular surface disease that can cause visual impairment if it progressively invades the cornea. Although many pieces of research showed ultraviolet radiation is a trigger of pterygium pathological progress, the underlying mechanism in pterygium remains indistinct.

METHODS

In this study, we used microarray to evaluate the changes of transcripts between primary pterygium and adjacent normal conjunctiva samples in China. Then, we performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analyses. Moreover, we constructed protein-protein interaction (PPI) and miRNA-mRNA regulatory networks to predict possible regulatory relationships. We next performed gene set enrichment analysis (GSEA) to explore the similarities and differences of transcripts between Asian studies from the Gene Expression Omnibus database. Furthermore, we took the intersection of differentially expressed genes (DEGs) with other data and identified hub genes of the development of pterygium. Finally, we utilized real-time quantitative PCR to verify the expression levels of candidate genes.

RESULTS

A total of 49 DEGs were identified. The enrichment analyses of DEGs showed that pathways such as the Wnt-signaling pathway and metabolism-related pathways were upregulated, while pathways such as hormone-related and transcription factor-associated pathways were downregulated. The PPI and miRNA-mRNA regulatory networks provide ideas for future research directions. The GSEA of selecting Asian data revealed that epithelial-mesenchymal transition and myogenesis existed in the pathology of pterygium in the Asian group. Furthermore, five gene sets (interferon-gamma response, Wnt beta-catenin signaling, oxidative phosphorylation, DNA repair, and MYC targets v2) were found only in our Chinese datasets. After taking an intersection between selecting datasets, we identified two upregulated (SPP1 and MYH11) and five downregulated (ATF3, FOS, EGR1, FOSB, and NR4A2) hub genes. We finally chose night genes to verify their expression levels, including the other two genes (SFRP2 and SFRP4) involved in Wnt signaling; Their expression levels were significantly different between pterygium and conjunctiva.

CONCLUSIONS

We consider hormone-related, metabolic, and Wnt signaling pathways may be important in the pathology of pterygium development. Nine candidate genes we identified deserve further study and can be potential therapeutic targets.