Pathogenesis of pterygia: role of cytokines, growth factors, and matrix metalloproteinases

A Phase IIa Multicenter, Randomized, Vehicle-Controlled, Dose Escalating Study to Evaluate the Safety, Efficacy, and Pharmacokinetics of CBT-001 Ophthalmic Solution in Patients With Primary or Recurrent Pterygium

Purpose

To evaluate the safety and efficacy of CBT-001, a multitarget tyrosine kinase inhibitor eyedrop, for pterygia.

Design

Phase II clinical trial. Stage 1 was a single center, open-labeled, vehicle-controlled study. Stage 2 was a multicenter, randomized, double-masked, vehicle-controlled trial.

Participants

Patients with primary or recurrent pterygia.

Main Outcome Measures

The primary efficacy end point was lesion vascularity based on masked grading of photographs by an independent reading center. Other end points included dimensions of pterygia and safety.

Methods

In stage 1, 24 eyes of 24 patients received 1 drop of CBT-001 in a dose escalation fashion (0.02%, 0.05%, and 0.2%) to determine the maximally tolerated dose based on adverse events (AEs) and blood drug levels. In stage 2, subjects were randomly assigned to receive the maximally tolerated dose of CBT-001 or vehicle dosed 3 times a day for 4 weeks with a 20-week follow-up.

Results

In stage 1, the plasma maximum concentration values for all doses of CBT-001 were at or below the limit of detection (0.01 ng/ml). The most commonly reported AEs were mild foreign body sensation and irritation. CBT-001 0.2% was evaluated in stage 2. Baseline demographic characteristics were similar between patients receiving CBT-001 (n = 25) and vehicle (n = 23). After 4 weeks of dosing, the mean change from baseline in pterygium vascularity scores was -0.8 ± 0.7 (mean ± standard deviation) in subjects receiving CBT-001 0.2% and 0.0 ± 0.5 in subjects receiving vehicle (P < 0.001; 95% confidence interval: -1.12, -0.40). Pterygium vascularity scores remained significantly decreased, after the 4-week dosing period, at weeks 8 and 16, but not at week 24. The mean changes from baseline in the length of the pterygia were also significantly lower in subjects receiving CBT-001 compared with vehicle at weeks 2, 4, and 8 (P ≤ 0.014). The most commonly reported AEs were ocular, mild in severity, resolved after therapy, and did not result in discontinuation.

Conclusions

CBT-001 0.2% decreased pterygia vascularity and lesion length after 4 weeks of dosing with a prolonged effect after dosing. The drug was well tolerated with minimal detected systemic drug levels.

Financial Disclosures

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

Risk factors for pterygium: Latest research progress on major pathogenesis

A pterygium is a wedge-shaped fibrovascular growth of the conjunctiva membrane that extends onto the cornea, which is the outer layer of the eye. It is also known as surfer's eye. Growth of a pterygium can also occur on the either side of the eye, attaching firmly to the sclera. Pterygia are one of the world's most common ocular diseases. However, the pathogenesis remains unsolved to date. As the pathogenesis of pterygium is closely related to finding the ideal treatment, a clear understanding of the pathogenesis will lead to better treatment and lower the recurrence rate, which is notably high and more difficult to treat than a primary pterygium. Massive studies have recently been conducted to determine the exact causes and mechanism of pterygia. We evaluated the pathogenetic factors ultraviolet radiation, viral infection, tumor suppressor genes p53, growth factors, oxidative stress, apoptosis and neuropeptides in the progression of the disease. The heightened expression of TRPV1 suggests its potential contribution in the occurrence of pterygium, promoting its inflammation and modulating sensory responses in ocular tissues. Subsequently, the developmental mechanism of pterygium, along with its correlation with dry eye disease is proposed to facilitate the identification of pathogenetic factors for pterygia, contributing to the advancement of understanding in this area and may lead to improved surgical outcomes.

Primary Pterygium Excision Surgery: Analysis of Risk Factors and Clinical Outcomes

Purpose To evaluate clinical outcomes of primary pterygium excision surgery and analyze risk factors for pterygium recurrence. Setting Eye Treatment Centre, Cornea and External Diseases Service, Whipps Cross Hospital, London, United Kingdom. Methods Retrospective case series of eyes undergoing primary pterygium excision between August 2017 and July 2022. Patients who underwent "pterygium excision" documented in the electronic patient record system were identified. Patients with recurrent pterygium and those lost-to-follow-up were excluded. The duration of follow-up, type of surgery performed (primary conjunctival closure, conjunctival autograft, and amniotic membrane transplantation), recurrences with respect to the type of surgery performed, and postoperative complications were collected and analyzed. Results In total, 83 eyes (from 79 patients) were included. The mean age of our patient cohort was 59.3 ± 5.9 years. The most common ethnic distribution was Black Caribbean (15.7%). Conjunctival autograft was performed in 76 eyes (91.6%), primary conjunctival closure was performed in five eyes (6%) and amniotic membrane transplantation was performed in two eyes (2.4%). The recurrence rate with conjunctival autograft was 1.3% with a median time to recurrence of 2.98 months. Recurrence was significantly more common in patients below the age of 40 years (p=0.03). Recurrence was not significantly associated with gender (p=0.23), ethnicity (p=0.17), or grade of surgeon (p=0.38).  Conclusion Our findings demonstrate the effectiveness of conjunctival autograft with fibrin glue fixation for the surgical management of primary pterygium. Recurrence was found to be significantly more common in patients under the age of 40 years old. However, recurrence was not associated with ethnicity, gender, or surgeon grade.

Risk Factors for Recurrence in the Treatment of Recurrent Pterygium

PURPOSE

The aim of this study was to identify the postoperative recurrence rate of recurrent pterygium and to evaluate risk factors for the recurrence.

METHODS

This study was a retrospective interventional nonrandomized consecutive case series. In this single-center study, 119 eyes of patients with recurrent pterygium who underwent surgery with a follow-up period of >12 months after the surgery were analyzed. The clinical characteristics of pterygium were classified according to the length of corneal involvement and Tan grade. The main outcome was the recurrence rate. The secondary outcome was the risk factors for recurrence.

RESULTS

The mean follow-up period was 42 ± 28.6 months. Recurrence was observed in 15 patients (12.6%). The average postoperative recurrence period was 7.7 ± 6.7 months. Twelve patients experienced a recurrence within 12 months. Eyes with recurrence had a significantly greater length of corneal involvement (2.47 ± 0.72 mm) and number of previous surgery (1.9 ± 1.3) than those without (1.97 ± 0.74 mm, and 1.3 ± 0.7, both P = 0.04). Multivariate analysis showed that recurrence was significantly associated with the length of corneal involvement (odds ratio [OR] 2.38, 95% confidence interval [CI], 1.02-5.57, P = 0.05) and the number of previous surgeries (OR: 1.91, 95% CI, 1.03-3.58, P = 0.04) but not with sex (OR: 3.71, 95% CI, 0.90-15.2, P = 0.07), age (OR: 0.99, 95% CI, 0.94-1.04, P = 0.59), and use of mitomycin C (OR: 0.31, 95% CI, 0.07-1.21, P = 0.09).

CONCLUSIONS

The postoperative recurrence rate of recurrent pterygium was 12.6%. The preoperative length of corneal involvement and number of previous pterygium surgeries were significantly correlated with recurrence. Male sex and nonuse of mitomycin C tended to correlate with recurrence.

Expression of CD44, PCNA and E-cadherin in pterygium tissues

PURPOSE

Pterygium is a common ocular surface disease defined by fibrovascular conjunctival growth extending onto the cornea. However, its pathogenesis remains unclear. This study aimed to determine the role of CD44, proliferating cell nuclear antigen (PCNA), and E-cadherin in pterygium formation and recurrence.

METHODS

Sixty patients with pterygium participated in the study, and we collected conjunctival samples from 30 patients to form a control group. CD44, PCNA, and E-cadherin expressions in surgically excised pterygium were compared with tissue samples from the control group.

RESULTS

We observed that the percentages of CD44 and PCNA were statistically higher in the primary pterygium group and recurrent pterygium group than in the control group (P < 0.001 and P < 0.001, respectively). Conversely, E-cadherin values were statistically higher in the control group than in the primary and recurrent pterygium groups (P = 0.013 and P < 0.001, respectively).

CONCLUSION

Cell proliferation and cell adhesion factors may play important roles in the pathogenesis of pterygium.

Tear Protein Markers for Diabetic Retinopathy and Diabetic Macular Edema - Towards an Early Diagnosis and Better Prognosis

BACKGROUND

Diabetic eye disease is a highly prevalent and sight-threatening disorder. It is a disease of neuro-vascular unit of the retina, if left untreated can cause blindness. Therapeutic approaches followed for its treatment can only restrict the progression of the disease with highly variable results. There is no known biomarker for an early diagonsis of this disease, therefore by the time it is detected it goes beyond repair. This creates a massive demand for development of such biomarkers that help detect disease in its earlier stages.

METHODS

PUBMED (https://pubmed.ncbi.nlm.nih.gov/) was searched for articles relevant to the topic published till November 2023. The search was made using keywords such as Diabetic Retinopathy, inflammation, tear, biomarker, proteomics etc. The studies providing relevant information to prove the importance of biomarker discovery were chosen. After compiling the data, the manuscript writing was planned under relevant headings and sub-headings.

RESULTS

The review provides a comprehensive overview of all the tear protein biomarker studies in the field of DR and DME. Briefly, their potential in other diseases is also elucidated. While there are many studies pertaining to DR biomarkers, the identified markers lack validations which has restricted their usage in clinics. In case of DME, there was no such study towards biomarker discovery for its diagnosis and prognosis.

CONCLUSIONS

The review highlights major studies and their lacunae in the field of biomarkers discovery for DR and DME.

Expression of placental growth factor, neuropilin-1, and neuropilin-2 in primary pterygium tissue

PURPOSE

The aim of this study was to evaluate the expression of placental growth factor (PLGF), neuropilin-1 (NP-1), and neuropilin-2 (NP-2) molecules in primary pterygium tissue compared with normal conjunctival tissue.

METHODS

The records of 42 patients who underwent excision surgery with autografts for primary pterygium (pterygium group) and 20 patients who underwent conjunctival nevus excision surgery (control group) in the same period were reviewed retrospectively. The samples obtained from the pterygium tissues in the pterygium group and the clean conjunctival tissues adjacent to the nevus in the control group were collected from the archive. Immunohistochemical stains of the primary antibodies-1/100 diluted PLGF, NP-1, and NP-2 (Abcam Cambridge Science Park, UK)-were applied to all groups. Staining intensities and the percentage of positive cells in epithelial, endothelial, stromal, and inflammatory cells were analyzed by an experienced pathologist.

RESULTS

The positivity rates of PLGF and NP-2 expression in epithelial, endothelial, stromal, and inflammatory cells were found to be higher in the pterygium group than in the control group (PLGF: p < 0.001, p < 0.001, p = 0.001, and p < 0.001, respectively; NP-2: p < 0.001 for all). Staining intensities for PLGF and NP-2 were higher in the pterygium group than in the control group (PLGF: p < 0.001, p < 0.001, p = 0.005, and p < 0.001, respectively; NP-2: p < 0.001, p < 0.001, p = 0.001, and p < 0.001, respectively). However, no significant differences were found in any cell type in terms of NP-1 expression positivity rates (p = 0.730, p = 0.121, p = 0.524, and p = 0.624, respectively) or staining intensity (p = 0.716, p = 0.147, p = 0.147, and p = 0.780, respectively).

CONCLUSION

PLGF and NP-2 levels were found to be higher in pterygium tissue, while there was no difference in NP-1. These results indicate the possible roles of NP-2 and PLGF in primary pterygium.

Comparison of mini-simple limbal epithelial transplantation and conjunctival-limbal autograft for the treatment of primary pterygium: a randomised controlled trial

PURPOSE

The purpose of this double-masked, parallel randomised controlled trial was to compare the recurrence rate and other outcomes between conjunctival-limbal autograft (CLAu) and mini-simple limbal epithelial transplantation (mini-SLET) after excision of pterygium.

METHODS

Eligibility criteria for participants was the presence of a primary nasal pterygium extending equally to or greater than two millimetres on the cornea on its horizontal axis from the nasal limbus. The participants were allocated into two groups (CLAu and mini-SLET) using simple randomisation with a table of random numbers. Participants and the outcome assessor were masked to the intervention. The study protocol is listed and available on https://clinicaltrials.gov (Identifier: NCT03363282).

RESULTS

A total of 61 eyes were enrolled in the study, 33 underwent CLAu (group 1) and 28 mini-SLET (group 2), all eyes were analysed in each group. At 2, 3, 6 and 12 months the CLAu group exhibited a recurrence of 0%, 6.1%, 8.1% and 8.1%, while the mini-SLET exhibited a recurrence of 0%, 17.9%, 50% and 53.5% (p<0.05). There were no intraoperative or postoperative complications in either of the two groups.

CONCLUSION

The findings of this study suggest that mini-SLET has a higher recurrence rate and provides no advantage over CLAu in the treatment of primary pterygium.

Are Periocular and Systemic Allergy Conditions Risk Factors for Pterygium?

PURPOSE

To evaluate risk factors for pterygium and prevalence of periocular and systemic diseases among patients with pterygium.

METHODS

A retrospective case-control study was conducted among members of Clalit Health Services (CHS) in Israel, from 2001 to 2022. A total of 13,944 patients diagnosed with pterygium were included. For each case, three controls were matched among all CHS patients according to year of birth, sex, and ethnicity. Mixed models were used to assess differences in demographic characteristics, ocular and systemic diseases between the groups. Generalized estimating equation (GEE) logistic regression was used to estimate the odds ratios (OR) and adjust for confounders.

RESULTS

The average age of pterygium patients was 49 ± 17 years; 51% were male. The results showed significant associations between pterygium and risk factors of vernal kerato-conjunctivitis (OR 2.52, 95% confidence interval [CI]: [1.96-3.24]), chronic allergic conjunctivitis (OR 1.98, 95% CI: [1.65-2.39]), blepharitis (OR 1.91, 95% CI: [1.78-2.04]), chalazion (OR 1.47, 95% CI: [1.30-1.67]) and unspecified systemic allergy (OR 1.21, 95% CI [1.09-1.34]), after adjusting for rural residency status. Glaucoma (OR 0.74, 95% CI [0.64-0.85]) and smoking (OR 0.70, 95% CI [0.66-0.75]) were protective factors against pterygium.

CONCLUSION

Systemic and periocular inflammatory and allergic diseases are risk factors for pterygium.

High-throughput screening of cytochrome P450 (CYP) family of genes in primary and recurrent pterygium

Pterygium is a common degenerative disease characterized fibrovascular outgrowth towards cornea. Around 200 million people have been reported to be affected by the pterygium in the world. Although the risk factors for pterygium are well documented, the molecular pathogenesis of pterygium seems to be very complex and remains highly elusive. However, the common sense for the development of pterygium appears to be deregulation of growth hemostasis due to aberrant apoptosis. In addition, pterygium shares many features with human cancers, including dysregulation of apoptosis, persistent proliferation, inflammation, invasion, and relapse following resection. Cytochrome P450 (CYP) monooxygenases are a superfamily of heme-containing enzymes with a wide range of structural and functional diversity. In the present study, we aimed to identify significant expression signatures of CYP gene in pterygium. For the study, a total number of 45 patients (30 primary and 15 recurrent pterygium) were included. For the high-throughput screening of CYP gene expression, Fluidigm 96.96 Dynamic Array Expression Chip was used and analyzed with BioMark™ HD System Real-Time PCR system. Remarkably, CYP genes were identified to be significantly overexpressed in both primary and recurrent pterygium samples. Most prominent overexpression was observed in CYP1A1, CYP11B2 and CYP4F2 in primary pterygium and CYP11A1 and CYP11B2 in recurrent pterygium. Consequently, present findings suggest the significant involvement of CYP genes in the development and progression of pterygium.

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.

Epidemiologic characteristics and the change of surgical methods of pterygium and pseudopterygium from 2013 to 2019 in China: A retrospective analysis

Introduction

Pterygium is a common multifactorial external eye disease, which causes various ocular symptoms and negatively affects appearance. The aim of this study was to analyze the epidemiological characteristics and the change of surgical methods of pterygium and pseudopterygium in China from 2013 to 2019.

Materials and methods

This study was a hospital-based nationwide retrospective study to estimate the epidemiologic characteristics and the change of surgical methods of pterygium and pseudopteygium in China from 2013 to 2019. The data was extracted from the Hospital Quality Monitoring System (HQMS) database. The diagnosis was based on the tenth revision of the International Classification of Diseases (ICD-10) code.

Results

Our study included 1,007,800 pterygium and 2,681 pseudopteygium inpatients. From 2013 to 2019, the proportion of pterygium and pseudopterygium patients who underwent surgery, among all ophthalmology inpatients, increased from 3.3% in 2013 to 7.84% in 2019. The male-female ratio of surgically treated pterygium and pseudopterygium is 1:1.8 and 1.6:1 respectively. Among all age groups, the hospitalized pterygium patients who received surgery were mainly 60-69 years old, accounting for 36.53%. The pseudopterygium patients who received surgery were mostly 50-59 years old, accounting for 24.02%. Among the 31 provinces of mainland China, Yunnan Province has the highest proportion of pterygium patients treated surgically (6.40%), while Shanghai has the highest proportion of pseudopterygium patients treated surgically (12.98%). The most common occupation of participants in the study was farmer, accounting for 47.62% and 28.53%, respectively. During the study period, the application of autologous stem cell transplantation increased year by year, and became the first choice for pterygium and pseudopterygium surgery.

Discussion

This study was the first to describe the epidemiological characteristics and surgical methods of hospitalized pterygium and pseudopterygium patients in China. This study provides important information for better diagnosis, treatment and prevention of pterygium and pseudopterygium.

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.

The Influence of Pterygium on Meibomian Glands and Dry Eye Parameters

SIGNIFICANCE

Mechanical factors are also associated with meibomian gland dysregulation in patients with pterygium. Dry eye parameters were assessed, and the results support the association between pterygium and dry eye disease.

PURPOSE

This study aimed to investigate how meibomian gland dysfunction and dry eye parameters relate to the existence of pterygium.

METHODS

Patients with pterygium and healthy volunteers of similar age and demographic characteristics were included. Schirmer 1 test, Ocular Surface Disease Index score, fluorescein tear film breakup time, and ocular surface staining scores (Oxford score) were recorded. Meiboscores were estimated based on meibomian gland loss rate on infrared meibography (SL-D701; Topcon, IJssel, the Netherlands). The symmetry of meibomian gland loss with respect to eyelid midline was assessed.

RESULTS

Fifty-four eyes with pterygium (group 1) and 50 eyes of healthy volunteers (group 2) were included. The mean ages were 54.0 ± 12.3 and 52.3 ± 8.0 years, respectively. Schirmer 1 test results and tear film breakup time were lower in group 1 ( P = .007, P < .001). Oxford and Ocular Surface Disease Index scores were significantly higher in group 1 ( P = .009, P < .001). The mean meiboscores were significantly higher in group 1 ( P < .001). There was meibomian gland depletion in 90.7% (49 of 54) of group 1 and 32% (16 of 50) of group 2 ( P < .001). Meibomian gland loss region was distributed asymmetrically in 75.5% (37 of 49) of the eyes in group 1, but not in any of the eyes in group 2. The asymmetry was located on the side where the pterygium was detected in 94.5% (35 of 37) of these eyes.

CONCLUSIONS

Meibomian glands are influenced morphologically and functionally in eyes with pterygium. The overlap of the pterygium location and meibomian gland abnormality suggests a direct mechanical relationship. In managing pterygium patients, the possibility of meibomian gland dysfunction and associated evaporative dry eye should be considered.

Prevalence and associated factors for pterygium in a Chinese rural population with type 2 diabetes in a cross-sectional study: Jiangsu Diabetic Eye Disease Study (JDEDS)

PURPOSE

To investigate the pterygium prevalence and evaluate risk factors of pterygium in rural type 2 diabetic (D2M) patients aged 50 years and above in Funing Country, Jiangsu Province, China.

METHODS

A cross-sectional ophthalmic survey was conducted in type 2 diabetes mellitus (D2M) patients aged ≥ 50 years in Funing County, Jiangsu Province, China, which was named Jiangsu Diabetic Eye Disease Study (JDEDS). All participants underwent a comprehensive questionnaire and ocular examination. Pterygium was diagnosed by slit lamp examination. The risk factors associated with pterygium were evaluated with logistic regression models.

RESULTS

The prevalence of pterygium was 22.37% (n = 427) and 95% confidence interval (CI) (20.50-24.24%) in D2M patients aged 50 years and above in JDEDS. The prevalence of pterygium was 18.32% (95% CI 15.33-21.32%) in men and 24.43% (95% CI 22.06-26.80%) in women. Women had a higher prevalence than men (p = 0.001). Multivariate analysis showed, for male participants with D2M, pterygium was independently associated with increasing age [70-79 years: OR and 95% CI 2.49(1.20-5.18), p = 0.014; ≥ 80 years: 4.84(2.04-11.47), p < 0.001], while cigarette smoking was the protective factors, especially in current smoker [OR and 95% CI 0.79(0.67-0.92); p = 0.003]. For female participants with D2M, age [60-69 years OR and 95% CI 1.68(1.07-2.62), p = 0.023; 70-79 years: 2.62(1.69-4.06), p < 0.001; ≥ 80 years:3.24(1.70-5.90), p < 0.001], hypertension [OR and 95% CI 1.40(1.05-1.87), p = 0.024], BMI 24-27.9 [OR and 95% CI 1.20(1.00-1.44), p = 0.047], higher HbA1c [(5.6-7.9) % OR and 95% CI 1.42(1.10-1.82), p = 0.006; (8.0-9.9) %: 1.32(1.10-1.58), p = 0.003] were risk factors.

CONCLUSIONS

D2M patients aged over 50 years has a high prevalence of pterygium in JDEDS. The pterygium prevalence is higher in female D2M participants. Diabetes and related factors may be risk factors of pterygium in female D2M patients. Further studies are needed to explore the gender difference in the pathogenesis of pterygium in D2M subjects.

[Correction of refractive disorders after surgical treatment of recurrent pterygium (case study)]

Lamellar keratoplasty is the most effective and safe method of surgical treatment of recurrent pterygium, providing restoration of the corneal frame and optical properties and a high anti-relapse effect due to the barrier properties of the lamellar graft. However, potential postoperative changes in the regularity of the anterior and posterior surfaces of the cornea (especially in case of advanced stage of fibrovascular tissue growth) do not always allow achieving high functional results of treatment. The article presents a clinical case that demonstrates the effectiveness and safety of excimer laser correction of refractive disorders after surgical treatment of pterygium.

Changes in Tear Proteomic Profile in Ocular Diseases

The search for proteomic biomarkers in ocular disease is one of the most important research directions in recent years. Reliable biomarkers can be an immense adjuvant for both diagnostic and therapeutic approaches. There is no more readily available ocular tissue for proteomic analysis than tear film, which makes an interesting target for the biomarker search. Tear film is a complex fluid consisting of a superficial lipid layer, which covers the aqueous-mucous layer. Its complexity makes it a perfect candidate for all the "omics" approaches. Glaucoma, cataract, age-related macular degeneration, and other diseases are commonly thought to have a multifactorial background. Currently, no reliable non-invasive tests are available that would help physicians with screening and further patient management. The aim of the study is to present modern methods of measuring biomarkers in tears, with particular emphasis on spectrometric methods, and to discuss their diagnostic and therapeutic usefulness.

The role of cyclophilin A and VEGF in the pathogenesis and recurrence of pterygium

PURPOSE

Pterygium is defined as overgrowth of abnormal conjunctival tissue on the cornea. Many proinflammatory cytokines and various growth factors have been implicated in the pathogenesis of pterygium. Cyclophilin A (CyPA) is a protein that is used by cyclosporin A (CsA) as the intracellular receptor and is secreted in response to inflammatory stimuli. Vascular endothelial growth factor (VEGF) is the most important angiogenic factor. This study aimed to assessment CyPA and VEGF immunoreactivity in pterygium specimens.

MATERIAL AND METHODS

In this cross-sectional study, 32 primary pterygium samples, 25 recurrent pterygium samples and 25 normal bulbar conjunctiva samples were included. The histopathological features, CyPA and VEGF immunoreactivity of surgically excised pterygium specimens were compared with control conjunctiva specimens obtained from normal bulbar conjunctiva.

RESULTS

CyPA immunoreactivity in vascular endothelial cells, epithelial cells, and stromal cells was remarkably higher in pterygium specimens than control conjunctiva specimens (p = 0.004, p = 0.012, p = 0.001, respectively). Morever, VEGF immunoreactivity in endothelial cells was remarkably higher in pterygium specimens than control conjunctiva specimens (p < 0.001). When recurrent and primary pterygium specimens were compared, CyPA and VEGF immunoreactivity was remarkably higher in recurrent pterygium (p = 0.001, p = 0.001, respectively). Pearson correlation showed that CyPA immunoreactivity correlated with stromal vascularity, stromal inflammation, and mast cell count in pterygium specimens.

CONCLUSION

This study aimed to assess CyPA and VEGF may have a important function in the pathogenesis and recurrence of pterygium.

Evaluating the Efficacy and Safety of Different Pterygium Surgeries: A Review of the Literature

The search for the "gold standard" in the surgical treatment of pterygium has been ongoing for over two decades. Despite the development of various surgical techniques, recurrence rates range from 6.7% to 88% depending on the method used. This review discusses the latest and most commonly used methods for the surgical removal of pterygium, primarily focusing on efficacy and safety. Moreover, this review includes articles that either evaluated or compared surgical methods and clinical trials for primary and recurrent pterygium. Limited data are available on combined methods as well as on the efficacy of adjuvant treatment. The use of adjuvant intraoperative mitomycin C (MMC) and conjunctival autografting (CAU) are the two most highly recommended options, as they have the lowest rates of postoperative recurrence.

Case series about physiological astigmatism and the impact of pterygium surgery

Introduction

Pterygium is a benign conjunctival fibrovascular neoformation progressively encroaching on the cornea, it can cause corneal distortion and induce astigmatism, or aggravate pre-existing physiological astigmatism, which is defined as ≤ 0.50 D and not requiring optical correction. The radical treatment of pterygium is purely surgical, with conjunctivo-limbal grafting and conjunctival autografting emerging as the surgical techniques of choice. The main objective of the study was to investigate whether pterygium surgery does not worsen the preoperative physiological astigmatism.

Material and methods

This is a prospective cohort study conducted in the ophthalmology department of the Mohammed V Military Hospital in Rabat over a period of 12 months, including 43 stage II/III/IV pterygia that were operated on by conjunctival autograft by the same surgeon. First, we looked for an association between pterygium surgery and variations in astigmatism. For quantitative variables we used the Wilcoxon test. In a second step we split the file into two distinct groups according to the value of preoperative astigmatism≤ 0.5 D or >0.5 D in order to detect the impact of pterygium surgery on physiological astigmatism. Statistical analysis of the data was performed by comparing the distribution of these characteristics.

Results

The median astigmatism was 1 D (0.25; 2.50). 35% of our population had preoperative astigmatism ≤0.5 D. The Wilcoxon test showed that there was a statistically significant difference between preoperative and postoperative astigmatism (p = 0.001). The paired sample T-test showed no statistically significant difference between the preoperative and postoperative outcome in the physiological astigmatism population (p = 0.53).

Conclusion

Many studies have shown the benefits of pterygium excision on astigmatism, but few studies have specified the impact of this surgery on physiological astigmatism. Our study showed that pterygium surgery does not alter physiological astigmatism.

•

We have not had any cases under the age of 20.

•

Surgical treatment of pterygium generally improves postoperative astigmatism.

•

Pterygium surgery was neither a protective nor a risk factor.

Doxycycline Suppresses Vasculogenic Mimicry in Human Pterygium Fibroblasts

PURPOSE

To explore the effect of doxycycline on vasculogenic mimicry (VM) formation and the potential mechanism in human pterygium fibroblasts in order to find novel targets for pterygium therapy.

METHODS

First, we demonstrate the existence of VM in 73 pterygium specimens by CD31 and periodic acid Schiff (PAS) dual staining. Then we used cell counting kit-8, clone formation assay and flow cytometry to prove the inhibitory effect of doxycycline on cell proliferation and apoptosis. The VM formation was evaluated through wound healing assay, cell transwell assay and three-dimensional cell culture combined with PAS staining. Finally, we used Western blot to testify the correlation of the VM and the factors in protein level preliminarily.

RESULTS

Our results showed that VM existed in human pterygium specimens exactly. Otherwise, in human pterygium fibroblasts, doxycycline induced a dose-dependent inhibitory effect on cell proliferation and apoptosis induction. Besides, doxycycline significantly suppressed vasculogenic mimicry tube formation, cell migration and invasion. Furthermore, doxycycline impaired the expression of MMP-9, MMP-2 and VEGF which may related to pterygium VM formation.

CONCLUSIONS

Doxycycline decelerated pterygium progression might be through inhibiting VM formation according to the downregulation of MMP-9, MMP-2 and VEGF, which may provide the basis of further studies involving doxycycline for pterygium treatment.

Environmental exposures to lead, cadmium, and mercury and pterygium in Korean adults

Pterygium, one of the most common eye disorders, is an abnormal fibrovascular proliferation extending from the conjunctiva to the cornea. The mechanism of development in pterygium has not been fully elucidated; however, oxidative stress is suggested to be one of the major causes. Heavy metals such as lead (Pb), cadmium (Cd), and mercury (Hg) enter the human body and induce oxidative stress. However, no study has investigated the association of these heavy metals with pterygium. Therefore, this study aimed to evaluate the associations of environmental exposures to Pb, Cd, and Hg with pterygium in the Korean general adults. We analyzed data from 6,587 adults (≥ 20 years of age) who participated in the Korea National Health and Nutrition Examination Survey (KNHANES) 2008-2011. Pterygium was diagnosed as the presence of a wing-shaped fibrovascular growth. The exposures of Pb, Cd, and Hg were estimated by measuring blood concentrations. The prevalence of pterygium in this study population was 4.0% (348 subjects). After adjusting for potential confounders, the Pb level in blood was found to have a significant dose-dependent association with pterygium (p for trend = 0.001), and its highest quintile (vs. the lowest) had an odds ratio (OR) of 2.22 (95% CI: 1.30, 3.78) for pterygium. The Hg level in blood in the second quintile (vs. the lowest) had an OR of 1.64 (95% CI: 1.04, 2.59) for pterygium. In conclusion, this study suggests that environmental exposures to Pb and Hg in the Korean general adults may be related to the development of pterygium.

Bindehautdegenerationen und -neoplasien

Erhabenheiten der Bindehaut entstehen durch Gewebevermehrung, die entweder degenerativ oder neoplastisch, aber auch entzündlich sein können. In diesem Artikel werden degenerative (Pterygium und Pinguecula) sowie benigne und maligne neoplastische Bindehautveränderungen (epitheliale, melanozytäre und vaskuläre Tumoren, Choristome sowie Metastasen) bezüglich der Pathogenese, Symptome, Diagnostik und aktuellem Stand der Behandlung dargestellt.

Extracellular Vesicles in Corneal Fibrosis/Scarring

Communication between cells and the microenvironment is a complex, yet crucial, element in the development and progression of varied physiological and pathological processes. Accumulating evidence in different disease models highlights roles of extracellular vesicles (EVs), either in modulating cell signaling paracrine mechanism(s) or harnessing their therapeutic moiety. Of interest, the human cornea functions as a refractive and transparent barrier that protects the intraocular elements from the external environment. Corneal trauma at the ocular surface may lead to diminished corneal clarity and detrimental effects on visual acuity. The aberrant activation of corneal stromal cells, which leads to myofibroblast differentiation and a disorganized extracellular matrix is a central biological process that may result in corneal fibrosis/scarring. In recent years, understanding the pathological and therapeutic EV mechanism(s) of action in the context of corneal biology has been a topic of increasing interest. In this review, we describe the clinical relevance of corneal fibrosis/scarring and how corneal stromal cells contribute to wound repair and their generation of the stromal haze. Furthermore, we will delve into EV characterization, their subtypes, and the pathological and therapeutic roles they play in corneal scarring/fibrosis.

[Conjunctival Degeneration and Neoplasia]

Conjunctival tumors result from gain of tissue, which can be either degenerative or neoplastic, but also inflammatory. In this article, degenerative (pterygium and pinguecula) as well as benign and malignant neoplastic conjunctival changes (epithelial, melanocytic and vascular tumors, choristomas as well as metastases) are discussed with regard to pathogenesis, symptoms, diagnostics and current status of treatment.

Evaluation of the Efficacy of Different Pterygium Surgeries in Polish Caucasian Population

The aim of the study was to compare the efficacy of the two most commonly used surgical methods for pterygium removal in the Polish population, conjunctival autograft versus amniotic membrane transplantation, and to evaluate the postoperative recurrence rate. A retrospective analysis of the medical records was conducted, including 65 patients who underwent surgery for primary or recurrent pterygium at an ophthalmology clinic in Bialystok, Poland, between 2016 and 2020. Surgical success (no regrowth) was achieved in almost half of the amniotic membrane patients (44%) and in most of the conjunctival autograft patients (79%), with statistical significance. The odds of successful surgery were 79% lower for subjects with amniotic membranes than for those with conjunctival autografts (OR with 95% CI = 0.21 (0.05; 0.94); $p=0.045$ ). Our study confirms that the conjunctival autograft surgeries present more favorable success rates in Polish Caucasian population when compared to procedures involving amniotic membranes.

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.

Pterygium and Ocular Surface Squamous Neoplasia: Optical Biopsy Using a Novel Autofluorescence Multispectral Imaging Technique

In this study, differentiation of pterygium vs. ocular surface squamous neoplasia based on multispectral autofluorescence imaging technique was investigated. Fifty (N = 50) patients with histopathological diagnosis of pterygium (PTG) and/or ocular surface squamous neoplasia (OSSN) were recruited. Fixed unstained biopsy specimens were imaged by multispectral microscopy. Tissue autofluorescence images were obtained with a custom-built fluorescent microscope with 59 spectral channels, each with specific excitation and emission wavelength ranges, suitable for the most abundant tissue fluorophores such as elastin, flavins, porphyrin, and lipofuscin. Images were analyzed using a new classification framework called fused-classification, designed to minimize interpatient variability, as an established support vector machine learning method. Normal, PTG, and OSSN regions were automatically detected and delineated, with accuracy evaluated against expert assessment by a specialist in OSSN pathology. Signals from spectral channels yielding signals from elastin, flavins, porphyrin, and lipofuscin were significantly different between regions classified as normal, PTG, and OSSN (p < 0.01). Differential diagnosis of PTG/OSSN and normal tissue had accuracy, sensitivity, and specificity of 88 ± 6%, 84 ± 10% and 91 ± 6%, respectively. Our automated diagnostic method generated maps of the reasonably well circumscribed normal/PTG and OSSN interface. PTG and OSSN margins identified by our automated analysis were in close agreement with the margins found in the H&E sections. Such a map can be rapidly generated on a real time basis and potentially used for intraoperative assessment.

Evaluation of Cyclooxygenase-2 and p53 Expression in Pterygium Tissue Following Preoperative Intralesional Ranibizumab Injection

Introduction: Overexpression of vascular endothelial growth factor (VEGF), cyclooxygenase-2 (COX-2), and p53 are the postulated aetiopathogenesis in pterygium. VEGF is responsible for the induction of COX-2 expression, whereas p53 plays an important role in the regulation of VEGF. This study aimed to evaluate the immunohistochemistry of COX-2 and p53 expressions from excised pterygium tissue from patients who received intralesional ranibizumab (anti-VEGF) injection 2 weeks prior to pterygium surgery. Materials and Methods: An interventional comparative study involving patients presenting with primary pterygium was conducted between September 2015 and November 2017. The patients were randomized into either the intervention or control group. Patients in the intervention group were injected with intralesional ranibizumab (0.5 mg/0.05 ml) 2 weeks prior to surgery. Both groups underwent pterygium excision followed by conjunctival autograft. Immunohistochemistry staining was performed to evaluate COX-2 and p53 expressions in the excised pterygium tissue. Results: A total of 50 patients (25 in both the intervention and control groups) were recruited. There were 34 (68%) patients with grade III pterygium and 16 (32%) patients with grade IV pterygium. There was statistically significant difference in reduction of COX-2 expression in the epithelial layer [84.0% (95% CI: 63.9, 95.5)] (p = 0.007) and stromal layer [84.0% (95% CI: 63.9, 95.5)] (p < 0.001) between intervention and control groups. There was no significant difference in the reduction of p53 expression between the two groups. Conclusion: This study demonstrated the possible use of intralesional anti-VEGF treatment prior to pterygium excision as a potential future modality of adjunctive therapy for pterygium surgery.

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.

The Role of the Stromal Extracellular Matrix in the Development of Pterygium Pathology: An Update

Pterygium is a benign fibrovascular lesion of the bulbar conjunctiva with frequent involvement of the corneal limbus. Its pathogenesis has been mainly attributed to sun exposure to ultraviolet-B radiation. Obtained evidence has shown that it is a complex and multifactorial process which involves multiple mechanisms such as oxidative stress, dysregulation of cell cycle checkpoints, induction of inflammatory mediators and growth factors, angiogenic stimulation, extracellular matrix (ECM) disorders, and, most likely, viruses and hereditary changes. In this review, we aim to collect all authors’ experiences and our own, with respect to the study of fibroelastic ECM of pterygium. Collagen and elastin are intrinsic indicators of physiological and pathological states. Here, we focus on an in-depth analysis of collagen (types I and III), as well as the main constituents of elastic fibers (tropoelastin (TE), fibrillins (FBNs), and fibulins (FBLNs)) and the enzymes (lysyl oxidases (LOXs)) that carry out their assembly or crosslinking. All the studies established that changes in the fibroelastic ECM occur in pterygium, based on the following facts: An increase in the synthesis and deposition of an immature form of collagen type III, which showed the process of tissue remodeling. An increase in protein levels in most of the constituents necessary for the development of elastic fibers, except FBLN4, whose biological roles are critical in the binding of the enzyme LOX, as well as FBN1 for the development of stable elastin. There was gene overexpression of TE, FBN1, FBLN5, and LOXL1, while the expression of LOX and FBLN2 and -4 remained stable. In conclusion, collagen and elastin, as well as several constituents involved in elastic fiber assembly are overexpressed in human pterygium, thus, supporting the hypothesis that there is dysregulation in the synthesis and crosslinking of the fibroelastic component, constituting an important pathogenetic mechanism for the development of the disease.

RhoA/ROCK Signaling Regulates TGF-β1-Induced Fibrotic Effects in Human Pterygium Fibroblasts through MRTF-A

PURPOSE

The overexpression of transforming growth factor-beta1 (TGF-β1) after surgical excision often leads to excessive fibrosis, indicating the recurrence of pterygium. The aims of the present in vitro study were to investigate the role of RhoA/ROCK signaling in regulating fibrotic effects of primary human pterygium fibroblasts (HPFs), as well as to explore the possible mechanisms of these effects.

METHODS

Pterygium samples were obtained from surgery, and profibrotic activation was induced by TGF-β1. Cell proliferation was detected by CCK-8 assay; cell migration was detected by wound healing assay; quantitative real-time PCR and Western blot were used to detect the effects of TGF-β1 and the role of RhoA/ROCK signaling in the synthesis of alpha-smooth muscle actin (a-SMA), type I and III collagen (COL1 and COL3), and matrix metalloproteinase-9 (MMP9) in HPFs. The changes of signaling pathways were detected by Western blot; and pharmaceutical inhibition of RhoA/ROCK signaling and its downstream MRFT-A/SRF transcription pathway were used to assess their possible mechanism in HPFs fibrosis.

RESULTS

ROCK inhibitor Y-27632 decreased TGF-β1-induced cell proliferation and migration, reduced the TGF-β1-induced expression of profibrotic markers in HPFs, and suppressed TGF-β1-induced nuclear accumulation of Myocardin-related transcription factor A (MRTF-A) as well as accompanied elevation of F/G-actin ratio in HPFs. MRTF-A/Serum response factor (SRF) inhibitor CCG-100602 attenuated the TGF-β1-induced α-SMA expression and reduced myofibroblast activation in HPFs.

CONCLUSIONS

RhoA/ROCK signaling played a pivotal role in TGF-β1-induced fibrosis and myofibroblast activation in HPFs at least in part by inactivating the downstream MRTF-A/SRF transcriptional pathway.

Evaluation of pterygium severity with en face anterior segment optical coherence tomography and correlations with in vivo confocal microscopy

PURPOSE

To describe en face anterior segment optical coherence tomography (EF-OCT) characteristics of pterygia and their correlation with in vivo confocal microscopy (IVCM).

PATIENTS AND METHODS

In this observational case series, we prospectively included 21 eyes of 17 subjects with pterygium. All subjects underwent detailed ophthalmic examination, anterior segment photography, an ocular surface disease index (OSDI) questionnaire, IVCM, and EF-OCT. Eyes were divided into two groups according to pterygium severity (Modified Pterygium Classification System) and OSDI score. EF-OCT images for both groups were analyzed for surface area of Fuchs Patches (FP). The IVCM activity score was based on the number of inflammatory cells, blood vessels, activated keratocytes and the appearance of the cornea/pterygium at the head of the pterygium. The correlations between EF-OCT and IVCM images were then analyzed and compared in both groups.

RESULTS

EF-OCT permits clear visualization and evaluation of FPs and the border between the pterygium and the adjacent cornea. The severe pterygium group was characterized by irregular borders and larger FPs (0.13±0.06 mm² versus 0.06±0.02 mm² respectively) (P=0.003). The mean IVCM activity score was 2.36±0.81 in the severe pterygium group and 1.2±0.42 in the mild pterygium group (P=0.0013). There was a positive correlation between FP surface area and IVCM activity score. A larger FP surface area was associated with a higher activity score on IVCM.

CONCLUSION

EF-OCT allows good evaluation of pterygium extension, borders and FP surface area. EF-OCT analysis of pterygium could represent a simple, non-invasive and reproducible method to evaluate pterygium severity and activity.

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.

Bibliometric analysis and mapping knowledge domain of pterygium: 2000-2019

AIM

To track the knowledge structure, topics in focus, and trends in emerging research in pterygium in the past 20y.

METHODS

Base on the Web of Science Core Collection (WoSCC), studies related to pterygium in the past 20y from 2000-2019 have been included. With the help of VOSviewer software, a knowledge map was constructed and the distribution of countries, institutions, journals, and authors in the field of pterygium noted. Meanwhile, using co-citation analysis of references and co-occurrence analysis of keywords, we identified basis and hotspots, thereby obtaining an overview of this field.

RESULTS

The search retrieved 1516 publications from WoSCC on pterygium published between 2000 and 2019. In the past two decades, the annual number of publications is on the rise and fluctuated a little. Most productive institutions are from Singapore but the most prolific and active country is the United States. Journal Cornea published the most articles and Coroneo MT contributed the most publications on pterygium. From co-occurrence analysis, the keywords formed 3 clusters: 1) surgical therapeutic techniques and adjuvant of pterygium, 2) occurrence process and pathogenesis of pterygium, and 3) epidemiology, and etiology of pterygium formation. These three clusters were consistent with the clustering in co-citation analysis, in which Cluster 1 contained the most references (74 publications, 47.74%), Cluster 2 contained 53 publications, accounting for 34.19%, and Cluster 3 focused on epidemiology with 18.06% of total 155 co-citation publications.

CONCLUSION

This study demonstrates that the research of pterygium is gradually attracting the attention of scholars and researchers. The interaction between authors, institutions, and countries is lack of. Even though, the research hotspot, distribution, and research status in pterygium in this study could provide valuable information for scholars and researchers.

Pterygium: an update on pathophysiology, clinical features, and management

Pterygium is a relatively common ocular surface disease. The clinical aspects and the treatment options have been studied since many years ago, but many uncertainties still exist. The core pathologic pathway and the role of heredity in the development of pterygium are still attractive fields for the researchers. The role of pterygium in corneal irregularities, in addition to the refractive properties of pterygium removal, has been increasingly recognized through numerous studies. The association between pterygium and ocular surface neoplasia is challenging the traditional beliefs regarding the safe profile of the disease. The need for a comprehensive clinical classification system has encouraged homogenization of trials and prediction of the recurrence rate of the pterygium following surgical removal. Evolving surgical methods have been associated with some complications, whose diagnosis and management are necessary for ophthalmic surgeons. According to the review, the main risk factor of pterygium progression remains to be the ultraviolet exposure. A major part of the clinical evaluation should consist of differentiating between typical and atypical pterygia, where the latter may be associated with the risk of ocular surface neoplasia. The effect of pterygium on astigmatism and the aberrations of the cornea may evoke the need for an early removal with a purpose of reducing secondary refractive error. Among the surgical methods, conjunctival or conjunctival-limbal autografting seems to be the first choice for ophthalmic surgeons because the recurrence rate following the procedure has been reported to be lower, compared with other procedures. The use of adjuvant options is supported in the literature, where intraoperative and postoperative mitomycin C has been the adjuvant treatment of choice. The efficacy and safety of anti–vascular endothelial growth factor agents and cyclosporine have been postulated; however, their exact role in the treatment of the pterygium requires further studies.

[Pterygium: pathogenesis, diagnosis and treatment]

The pterygium is a frequent ultraviolet (UV) light-induced focal fibrovascular proliferation of the conjunctival tissue onto the cornea. Surgical excision should be performed in the case of reduced visual acuity, progressive astigmatism, impending invasion of the optical axis and ocular surface complaints. The main factors in preventing recurrence include optimal surgical treatment by an excision combined with a free conjunctival autograft, consistent postoperative treatment with preservative-free artificial tears and topical steroids as well as long-term UV protection.

Comparative Transcriptomic Analysis to Identify the Important Coding and Non-coding RNAs Involved in the Pathogenesis of Pterygium

Pterygium is a common ocular surface disease characterized by abnormal fibrovascular proliferation and invasion, similar to tumorigenesis. The formation of tumors is related to a change in the expression of various RNAs; however, whether they are involved in the formation and development of pterygium remains unclear. In this study, transcriptome analysis of messenger RNAs (mRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) of paired pterygium and normal conjunctiva was performed to explore key genes regulating the development of pterygium. In total, 579 mRNAs, 275 lncRNAs, and 21 circRNAs were differentially expressed (DE) in pterygium compared with paired conjunctival tissues. Functional enrichment analysis indicated that DE RNAs were associated with extracellular matrix organization, blood vessel morphogenesis, and focal adhesion. Furthermore, through protein-protein interaction network and mRNA-lncRNA co-expression network analysis, key mRNAs including FN1, VCAM1, and MMP2, and key lncRNAs including MIR4435-2HG and LINC00968 were screened and might be involved in the pathogenesis of pterygium. In addition, several circRNAs including hsa_circ_0007482 and hsa_circ_001730 were considered to be involved in the pterygium development. This study provides a scientific basis for elucidating the pathogenesis of pterygium and will be beneficial for the development of preventive and therapeutic strategies.

Cosmetic outcome of femtosecond laser-assisted pterygium surgery

Background

To examine the cosmetic outcome of femtosecond laser-assisted pterygium surgery (FLAPS) with conjunctival autograft (CAG) and its potential predictive factors.

Methods

This was a prospective interventional case series (NCT02866968). We included 29 patients (29 eyes) with primary pterygium who underwent FLAPS. Cosmetic outcome was graded by two graders (an ophthalmology resident and an experienced ophthalmologist) using Hirst classification system (1–4 = excellent–poor). Weighted Cohen’s kappa analysis was performed to examine the intra- and inter-rater reliability. The relationship between cosmetic outcome and various factors were determined by Spearman’s correlation coefficients (r).

Results

The preoperative severity of pterygium (Tan grading system) was mild/atrophic (7%), moderate/intermediate (62%), and severe/fleshy (31%). An ultrathin CAG (mean thickness of 74.5 ± 9.8 μm) was fashioned intraoperatively. An excellent cosmetic outcome of FLAPS (median ± IQR) was observed at 3 months (1.0 ± 1.0) and remained similar at 6 months (1.0 ± 0.0) and 12 months (1.0 ± 0.0) postoperatively. At final follow-up, 27 (93%) patients achieved good-to-excellent cosmetic outcome, with 1 (3%) patient having a poor outcome due to incomplete pterygium removal. Weighted kappa analysis of Hirst grading system showed excellent intra-rater (κ = 0.86–0.95) and inter-rater reliability (κ = 0.84–0.88). There was a weak and borderline significant correlation between good cosmetic outcome and reduced postoperative CAG thickness (r = 0.38, P = 0.06) but not with age, gender, preoperative pterygium severity, or intraoperative CAG thickness.

Conclusions

FLAPS can result in an excellent cosmetic outcome, which may be attributed to the beneficial effect of an ultrathin CAG.

Trial registration

ClinicalTrials.gov, NCT02866968. Registered in July 2016,

Supplementary Information

The online version contains supplementary material available at 10.1186/s40662-021-00230-w.

Exploring the Molecular Mechanisms of Pterygium by Constructing lncRNA-miRNA-mRNA Regulatory Network

Purpose

This research explores the aberrant expression of the long non-coding RNA (lncRNA), microRNA (miRNA), and messenger RNA (mRNA) in pterygium. A competitive endogenous RNA (ceRNA) network was constructed to elucidate the molecular mechanisms in pterygium.

Methods

We obtained the differentially expressed mRNAs based on three datasets (GSE2513, GSE51995, and GSE83627), and summarized the differentially expressed miRNAs (DEmiRs) and differentially expressed lncRNAs (DELs) data by published literature. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, protein-protein interaction (PPI), and gene set enrichment analysis (GSEA) analysis were performed. DEmiRs were verified in GSE21346, and the regulatory network of hub mRNAs, DELs, and DEmiRs were constructed.

Results

Overall, 40 upregulated and 40 downregulated differentially expressed genes (DEGs) were obtained. The KEGG enrichment showed the DEGs mainly involved in extracellular matrix (ECM)-receptor interaction, focal adhesion, and PI3K-Akt signaling pathway. The GSEA results showed that cornification, keratinization, and cornified envelope were significantly enriched. The validation outcome confirmed six upregulated DEmiRs (miR-766-3p, miR-184, miR-143-3p, miR-138-5p, miR-518b, and miR-1236-3p) and two downregulated DEmiRs (miR-200b-3p and miR-200a-3p). Then, a ceRNA regulatory network was constructed with 22 upregulated and 15 downregulated DEmiRs, 4 downregulated DELs, and 26 upregulated and 33 downregulated DEGs. The network showed that lncRNA SNHG1/miR-766-3p/FOS and some miRNA-mRNA axes were dysregulated in pterygium.

Conclusions

Our study provides a novel perspective on the regulatory mechanism of pterygium, and lncRNA SNHG1/miR-766-3p/FOS may contribute to pterygium development.

An Unexpected Incidence of Ocular Surface Neoplasia on Pterygium Surgery. A Retrospective Clinical and Histopathological Report

PURPOSE

To report the unexpected finding of ocular surface neoplasia (OSSN) on conjunctival tissue removed during pterygium surgery and subjected to histopathology analysis.

METHODS

This is an observational, descriptive retrospective study in which all the samples removed during surgery between 1997 and 2020 with a clinical diagnosis of pterygium were sent for histopathology analysis in which an unexpected OSSN was found.

RESULTS

There were 461 cases with a preoperative diagnosis of pterygium, with a mean age of 30.14 ± 10.6 years. In this group, there was an unexpected finding of OSSN in 69 cases (14.96%) of the surgical samples, with a mean age of 46 ± 8.2 years (31.86 ± 12.13).

CONCLUSIONS

The unexpected coincidence of pterygium and OSSN is frequent, although varies depending on the geographical location. We recommend performing a histopathology analysis on every pterygium removed.

[Antiangiogenic therapy in the surgical treatment of pterygium]

PURPOSE

To evaluate the effectiveness and safety of adjuvant anti-VEGF therapy in the surgical treatment of pterygium, and to determine the indications for its use.

MATERIAL AND METHODS

The study included 67 patients (69 eyes) with grade II-IV pterygium. Patients age was 58.8±12.6 years on average. Best corrected visual acuity (BCVA) varied between 0.01 and 1.0 (0.77±0.24). The patients were divided into 3 groups. The first group included 19 patients (19 eyes) with grade II-III pterygium who underwent «bare sclera» surgery and used aflibercept as adjuvant therapy. The second group included 21 patients (21 eyes) with grade II-IV pterygium who underwent auto conjunctival grafting surgery with no adjuvant therapy. The third group included 27 patients (29 eyes) with grade II-IV pterygium who had it removed in combination with single-time peripheral lamellar keratoplasty (PLK) and underwent adjuvant aflibercept therapy.

RESULTS

Among patients who underwent pterygium excision with adjuvant antiangiogenic therapy there were 5 cases (26%) of relapse during the observation period (23.38±8.96 months), among patients after pterygium excision with auto conjunctival plastic surgery - also 5 cases (24%) of relapse, and among patients who underwent LKP combined with anti-VEGF therapy there was only 1 case (3%) of relapse. Astigmatism has decreased by 0.24±0.5 (p=0.052) in the first group, by 1.21±1.0 (p<0.05) in the second group, and by 1.64±1.54 (p<0.05) in the third group compared with pre-surgical values, thus increasing average BCVA in all 3 patient groups by 0.1±0.13, 0.07±0.11 and 0.15±0.15, respectively.

CONCLUSION

The use of anti-VEGF agents as adjuvant therapy in the surgical treatment of pterygium is a safe method of reducing postoperative inflammation, fibrovascular proliferation and, subsequently, the amount of relapses.

Recurrent pterygium – features of surgical treatment

Pterygium is a fibrovascular degenerative condition of the subconjunctival tissue that proliferates and grows into the cornea in the form of a vascularized fold, destroying the surface layers of the stroma and Bowmans membrane. This disease is common throughout the world. The etiology is not clear, but it is known that the appearance of pterygium is associated with exposure of the eye to ultraviolet rays. The treatment of the de novo occurring pterygium is a relatively simple task and involves surgical removal. But a simple excision is currently unacceptable due to the high recurrence rate. In order to minimize the risk of relapse, numerous adjuvant treatment methods are used, which include anti-metabolites such as Mitomycin C and 5-fluorouracil, amniotic membrane, various types of conjunctival and or limbal grafts; medications such as anti-vascular endothelial growth factor are sometimes used. In the clinical case presented in the article, we successfully used the technique of anterior lamellar keratoplasty and autoconjunctival transplantation in combination with intra-operative use of anti-metabolite Mitomycin C in a young patient with recurrent stage IV pterygium (degree of activity 3) twice unsuccessfully operated on. As a result of this surgical technique, the transparency of the cornea was restored and high visual acuity was obtained.

Relative gene expression analysis of human pterygium tissues and UV radiation-evoked gene expression patterns in corneal and conjunctival cells

A sight threatening, pterygium is a common ocular surface disorders identified by fibrovascular growth of the cornea and induced by variety of stress factors, like ultraviolet (UV) exposure. However, the genes involved in the etiopathogenesis of this disease is not well studied. Herein, we identified the gene expression pattern of pterygium and examined the expression of pterygium-related genes in UV-B-induced human primary cultured corneal epithelial cells (HCEpCs), telomerase immortalized human corneal epithelial (hTCEpi), primary conjunctival fibroblast (HConFs) and primary pterygium fibroblast cells (HPFCs). A careful analysis revealed that the expression of 10 genes was significantly modulated (by > 10-fold). Keratin 24 (KRT24) and matrix metalloproteinase 9 (MMP-9) were dramatically upregulated by 49.446- and 24.214-fold, respectively. Intriguingly, UV-B exposure (50 J/m²) induced the upregulation of the expressions of MMP-9 in corneal epithelial cells such as HCEpCs and hTCEpi. Furthermore, UV-B exposure (100 and/or 200 J/m²) induced the upregulation of the expressions of MMP-9 in fibroblast such as HConFs and HPFCs. The exposure of HCEpCs to 100 and 200 J/m² UV-B induced significant expressions of KRT24 mRNA. Nevertheless, no expression of KRT24 mRNA was detected in HConFs and HPFCs. The findings provide evidence that the progression of pterygium may involve the modulation of extracellular matrix-related genes and vasculature development and the up-regulation of KRT24 and MMP-9 by UV stress. UV radiation may promote the modulation of these pterygium-related genes and induce the initiation and progression of human pterygium.

Proposal and validation of a new grading system for pterygium (SLIT2)

BACKGROUND/AIMS

To propose and validate a new pterygium grading system based on slit-lamp evaluation.

METHODS

This prospective cross-sectional study included 217 patients with pterygium. All patients underwent slit-lamp examination, and slit-lamp photographs were independently graded by two graders twice. A total of eight parameters were evaluated and all parameters were assigned with a score of 1-4 (normal-severe). Intra-rater and inter-rater reliability as determined by weighted Cohen's kappa analysis.

RESULTS

A total of 868 independent assessment, based on 217 slit-lamp images, were performed by two graders. For conjunctival assessment, the intra-rater reliability was excellent for body thickness (κ=0.81-0.89) and size at limbus (κ=0.87-0.92), substantial-to-excellent for body vascularity (κ=0.72-0.86), and moderate-to-excellent for body length (κ=0.57-0.81), whereas the inter-rater reliability was excellent for size at limbus (κ=0.86), substantial for body thickness (κ=0.72-0.73) and body vascularity (κ=0.66-0.75), and moderate for body length (κ=0.54-0.57). For corneal assessment, the intra-rater reliability was excellent for all four parameters (κ=0.84-0.90) whereas the inter-rater reliability was excellent for head length (κ=0.86-0.87), substantial-to-excellent for head vascularity (κ=0.78-0.82), substantial for Stocker's line (κ=0.79-0.80) and head thickness (κ=0.67-0.69). The grading system was named SLIT2, which included S tocker's line, S ize at limbus, L ength of head/body, I njection/vascularity of body/head, and T hickness of body/head.

CONCLUSION

The proposed SLIT2 grading system, consisting of eight components, may serve as a reliable tool to standardise the reporting of pterygium severity and disease recurrence for clinical and research applications.

miR-200a contributes to the migration of BMSCs induced by the secretions of E. faecalis via FOXJ1/NFκB/MMPs axis

Background

Upon migrating to the injured sites, bone marrow mesenchymal stem cells (BMSCs) play critical roles in the repair of bone lesion caused by chronic apical periodontitis. Emerging evidences have shown that Enterococcus faecalis is always associated with apical periodontitis, especially refractory apical periodontitis. But the mechanism underlying how Enterococcus faecalis affects the migration of BMSCs remains unclear.

Methods

The effects of Enterococcus faecalis supernatants on the migration of BMSCs were determined by transwell migration assays. miRNA sequencing was performed to detect the significantly differentially expressed miRNAs of BMSCs. Proteomics analysis was used to detect the protein expression alterations of BMSCs. Luciferase report assays were deployed to verify the targets of miRNA. Western blot analysis was performed to examine the expressions of matrix metalloproteinases-3, matrix metalloproteinases-9, Forkhead Box Protein J1 (FOXJ1), and nuclear factor kappa B (NFκB). The activations of NFκB were detected by luciferase assays with NFκBluc reporter.

Results

We found that Enterococcus faecalis supernatants could promote the migration of BMSCs. The upregulation of miR-200a-3p in this process contributed to BMSC migration through downregulating its target Forkhead Box Protein J1. Moreover, FOXJ1/ NFκB axis was found to regulate matrix metalloproteinases (MMPs) in this process.

Conclusions

These results above suggest that miR-200a contributes to the migration of BMSCs induced by the secretions of E. faecalis via FOXJ1/NFκB/MMPs axis.

Role of oxidative stress and vascular endothelial growth factor expression in pterygium pathogenesis and prevention of pterygium recurrence after surgical excision

PURPOSE

To assess the roles of oxidative stress and vascular endothelial growth factor (VEGF) in pterygium pathogenesis and prevention of pterygium recurrence after surgical excision.

METHODS

Surgically removed pterygium tissue from 35 pterygium patients and normal conjunctival samples from 15 patients matched for age and sex (used as controls) constituted the study samples. The conjunctival samples were preserved at - 80 °C until analysis. Catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH) and total antioxidant (TAO) enzymatic activity and the levels of nitric oxide (NO), malondialdehyde (MDA) and VEGF were studied in both groups. To evaluate the recurrence rate after surgical excision, the pterygium patients were further subdivided into three groups according to the adjuvant therapy used to prevent recurrence. Group 1 consisted of 10 patients who were treated with 0.2 mg mitomycin-c (MMC) for 2 min. Group 2 consisted of 12 patients treated with subconjunctival bevacizumab injection after surgical removal of the pterygium. Group 3 consisted of 13 patients who underwent combined treatment with 0.2 mg of MMC for 2 min and subconjunctival bevacizumab injection. The follow-up of patients in the three groups ranged from 7 to 15 months.

RESULTS

The activities of CAT, SOD, GSH and TAO were significantly lower in pterygium samples than in normal conjunctival samples (p < 0.0001 each). The levels of MDA (p = 0.046), NO (p < 0.0001) and VEGF (p < 0.0001) were significantly higher in pterygium patients than in controls. The lowest recurrence rate after surgical excision was that of the third group.

CONCLUSIONS

Oxidative stress and VEGF could play a role in the pathogenesis of pterygium as indicated by decreased antioxidant enzymatic activity and increased levels of VEGF in the pterygium tissue and the role of MMC and anti-VEGF therapy in decreasing the recurrence rate after surgical excision.