P53 expression in altered limbal basal cells of pingueculae, pterygia, and limbal tumors

Study of biomarkers p53, Ki-67, Bcl-2, and VEGF in pterygium

PURPOSE

To study the biomarkers present in primary pterygium samples of patients of Indian ethnicity and compare it with the samples obtained from the unaffected conjunctiva of the same eye.

METHODS

A prospective case-control study of 17 eyes in patients above 10 years of age with primary pterygium who underwent pterygium excision using limbal conjunctival autograft technique. The pterygium samples (cases) and conjunctival samples (controls) were sent for immunohistochemical (IHC) staining for the following biomarkers: p53, Bcl-2, Ki-67, and vascular endothelial growth factor (VEGF).

RESULT

The immunohistochemistry of the samples and the controls revealed p53 positivity in 47.05% of pterygium samples and 29.4% of controls ( P < 0.587). Nine cases each in pterygium and control samples were positive for Ki-67 expression. Differences in the staining pattern between the two groups were not statistically significant ( P < 1.000). Bcl-2 positivity was seen in 10 pterygium samples (58.8%) and 12 controls (70.5%), with no statistical difference between the two groups ( P < 0.455). VEGF expression was seen in both epithelial and endothelial cells of the samples and controls, with no statistical difference between the two groups, with P = 1.000 for the epithelial staining and P = 0.637 for endothelial staining.

CONCLUSION

The expression of biomarkers was comparable in both groups. We conclude that pterygium, against common belief, might not be a localized disease process but a global ocular phenomenon where the apparently healthy tissue also has some ongoing disease process at a molecular level.

Incidence of ocular surface squamous neoplasia in pterygium specimens

OBJECTIVE

Pterygium and ocular surface squamous neoplasia (OSSN) have been recognized as likely related conditions and share similar risk factors such as ultraviolet radiation and chronic inflammation. The purpose of this study is to review the incidence of OSSN in pathology specimens sent as pterygium at a single tertiary centre between 2010 and 2022.

METHODS

This is a retrospective chart review of patients operated on for pterygium between 2010 and 2022 at the University of Montreal Health Centre. Data collected include baseline demographics, results of pathology specimen, and clinical information for cases diagnosed as OSSN on pathology.

RESULTS

A total of 1559 patients were operated on for a clinical diagnosis of pterygium between 2010 and 2022, of which 854 patients (55%) were male. A total of 1142 specimens had available pathology reports, and most of the specimens were consistent with pterygium on pathology (1105 of 1142; 97%). There was an unexpected finding of 3 cases of OSSN (3 of 1142; 0.3%). Other diagnosis besides pterygium were seen in 3% of specimens (34 of 1142), including nevus (n = 12), spheroidal degeneration (n = 3), pyogenic granuloma (n = 3), and lymphangiectasia (n = 2). The 3 cases of OSSN included an 81-year-old male of French-Canadian background, a 52-year-old male of South Asian background, and a 59-year-old female of French-Canadian background. The pathology was diagnosed as conjunctival intraepithelial neoplasia (CIN) grade 3, CIN grade 2, and CIN grade 2, respectively.

CONCLUSION

The finding of OSSN in pterygium is rare in our population but can be clinically difficult to distinguish. It is important to send all pterygium specimens for pathology.

State of the Art of Pharmacological Activators of p53 in Ocular Malignancies

The pivotal role of p53 in the regulation of a vast array of cellular functions has been the subject of extensive research. The biological activity of p53 is not strictly limited to cell cycle arrest but also includes the regulation of homeostasis, DNA repair, apoptosis, and senescence. Thus, mutations in the p53 gene with loss of function represent one of the major mechanisms for cancer development. As expected, due to its key role, p53 is expressed throughout the human body including the eye. Specifically, altered p53 signaling pathways have been implicated in the development of conjunctival and corneal tumors, retinoblastoma, uveal melanoma, and intraocular melanoma. As non-selective cancer chemotherapies as well as ionizing radiation can be associated with either poor efficacy or dose-limiting toxicities in the eye, reconstitution of the p53 signaling pathway currently represents an attractive target for cancer therapy. The present review discusses the role of p53 in the pathogenesis of these ocular tumors and outlines the various pharmacological activators of p53 that are currently under investigation for the treatment of ocular malignancies.

TFOS Lifestyle Report: Impact of environmental conditions on the ocular surface

Environmental risk factors that have an impact on the ocular surface were reviewed and associations with age and sex, race/ethnicity, geographical area, seasonality, prevalence and possible interactions between risk factors are reviewed. Environmental factors can be (a) climate-related: temperature, humidity, wind speed, altitude, dew point, ultraviolet light, and allergen or (b) outdoor and indoor pollution: gases, particulate matter, and other sources of airborne pollutants. Temperature affects ocular surface homeostasis directly and indirectly, precipitating ocular surface diseases and/or symptoms, including trachoma. Humidity is negatively associated with dry eye disease. There is little data on wind speed and dewpoint. High altitude and ultraviolet light exposure are associated with pterygium, ocular surface degenerations and neoplastic disease. Pollution is associated with dry eye disease and conjunctivitis. Primary Sjögren syndrome is associated with exposure to chemical solvents. Living within a potential zone of active volcanic eruption is associated with eye irritation. Indoor pollution, "sick" building or house can also be associated with eye irritation. Most ocular surface conditions are multifactorial, and several environmental factors may contribute to specific diseases. A systematic review was conducted to answer the following research question: "What are the associations between outdoor environment pollution and signs or symptoms of dry eye disease in humans?" Dry eye disease is associated with air pollution (from NO2) and soil pollution (from chromium), but not from air pollution from CO or PM10. Future research should adequately account for confounders, follow up over time, and report results separately for ocular surface findings, including signs and symptoms.

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.

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.

The roles of mouse double minute 2 (MDM2) oncoprotein in ocular diseases: A review

Mouse double minute 2 (MDM2), an E3 ubiquitin ligase and the primary negative regulator of the tumor suppressor p53, cooperates with its structural homolog MDM4/MDMX to control intracellular p53 level. In turn, overexpression of p53 upregulates and forms an autoregulatory feedback loop with MDM2. The MDM2-p53 axis plays a pivotal role in modulating cell cycle control and apoptosis. MDM2 itself is regulated by the PI3K-AKT and RB-E2F-ARF pathways. While amplification of the MDM2 gene or overexpression of MDM2 (due to MDM2 SNP T309G, for instance) is associated with various malignancies, numerous studies have shown that MDM2/p53 alterations may also play a part in the pathogenetic process of certain ocular disorders (Fig. 1). These include cancers (retinoblastoma, uveal melanoma), fibrocellular proliferative diseases (proliferative vitreoretinopathy, pterygium), neovascular diseases, degenerative diseases (cataract, primary open-angle glaucoma, age-related macular degeneration) and infectious/inflammatory diseases (trachoma, uveitis). In addition, MDM2 is implicated in retinogenesis and regeneration after optic nerve injury. Anti-MDM2 therapy has shown potential as a novel approach to treating these diseases. Despite major safety concerns, there are high expectations for the clinical value of reformative MDM2 inhibitors. This review summarizes important findings about the role of MDM2 in ocular pathologies and provides an overview of recent advances in treating these diseases with anti-MDM2 therapies.

Pterygium Recurrence Rates in the Hispanic Population in the Northeastern United States

Purpose:

To determine the rate and factors affecting pterygium recurrence in the Hispanic population of the Northeastern United States, based on patient demographic information.

Methods:

In this retrospective cross-sectional study, data were collected on ethnically Hispanic patients from 2013 to 2018 who had primary single-headed pterygia excision and conjunctival autograft, with the minimum of 4-month follow-up time. This study was conducted in an academic institution in the Northeastern United States, with all patients being from the surrounding community.

Results:

In 168 Hispanic patients with confirmed primary single-headed pterygium, most pterygia occurred nasally (161/168). The average age of presentation was 46.3 ± 12.0 years (range, 23–77 years). There were 22 recurrences (13.1%), occurring at an average of 3.0 ± 1.6 months (1–8 months). This cohort demonstrated a unimodal recurrence distribution. Age is significantly inversely correlated with the incidence of recurrence (r = −0.219, P = 0.004), but not with the size of the recurrent pterygia (r = −0.112, P = 0.621). There was no significant difference between recurrence based on gender (P = 0.265), location (P = 0.824), or laterality (right or left eye) (P = 0.213). Mean corrected visual acuity improved from 20/40 to 20/32 after pterygium excision (P < 0.001). Cox regression analysis for age groups shows the risk of recurrence for patients aged 20–29 is 11.4-time that of patients aged 50 and above (P < 0.001).

Conclusions:

Recurrence occurred unimodally at around 3 months postoperatively. Younger patients are significantly more susceptible to recurrence. Future studies may seek to determine the incidence of pterygia and their recurrence patterns in relation to occupations and sun exposure time in a geographic area.

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.

Expression of p53 and Ki-67 proteins in patients with increasing severity and duration of pterygium

Purpose

Pterygium is a triangular fibrovascular subepithelial ingrowth of degenerative bulbar conjunctival tissue over the cornea. It is now considered to be a result of uncontrolled cellular proliferation as overexpression of p53 protein and Ki-67 nuclear protein was found in the epithelium. This study was done to find the expression of p53 and Ki-67 with the severity and duration of the pterygium to explain the etiopathogenesis.

Methods

Data were analyzed from 43 Indian participants of all age groups. All patients were divided according to the severity of pterygium (mild, moderate, and severe groups) and according to the duration of pterygium (<4 years and >4 years). The samples were studied by immunohistochemistry by using antibodies against p53 and Ki-67 proteins considering >5% expression as significant.

Results

Of 43 cases, p53 and Ki-67 expression were positive in 33 cases. In mild, moderate, and severe cases p53 positivity was 33.3%, 78.4%, 100%, respectively. P53 expression increased with duration, 79.3% positive in <4 years, and 92.9% positive in >4 years. With increasing severity of pterygium, mild, moderate, and severe cases, Ki-67 positivity was 66.7%, 78.37%, 66.7%, respectively. Ki-67 expression with duration, 79.3% positive in <4 years, and 85.7% positive in >4 years of the duration of pterygium with no statistical significance.

Conclusion

Our study revealed that with increasing duration and severity of pterygium, p53 expression was observed to be increasing. Ki-67 expression increased with the duration of pterygium but not with the severity.

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.

Bcl-2, p53, and Ki-67 expression in pterygium and normal conjunctiva and their relationship with pterygium recurrence

PURPOSE

Pterygium is a common lesion of the ocular surface, and its etiology and pathogenesis are still uncertain. This study aimed to investigate the role of apoptosis and proliferation in pterygium formation and recurrence.

MATERIALS AND METHODS

In this study, p53, Bcl-2, and Ki-67 expression levels were evaluated in primary pterygium (n = 35) and recurrent pterygium (n = 32) tissue samples and compared with normal conjunctiva (n = 30) tissue samples. In addition, recurrent pterygiums were divided into three groups based on recurrence time, and their p53, Bcl-2, and Ki-67 expression levels were compared.

RESULTS

The results show that p53, Bcl-2, and Ki-67 expression levels were significantly higher in the pterygium tissue samples as compared to the control group (p < 0.001, p < 0.001, and p < 0.001, respectively). When primary and recurrent pterygium tissues were compared, bcl-2 expression was higher in recurrent pterygium tissue samples (p = 0.003). However, when Ki-67 and p53 expression levels were evaluated, no significant difference was found between primary and recurrent pterygium (p = 0.215, p = 0.321, respectively). Also, p53 and Ki-67 expression were correlated in pterygium tissue samples, and Bcl-2 expression was significantly higher in pterygium that recurrence in the first 6 months after surgery. There was no difference between groups 1, 2, and 3 in terms of p53 and Ki-67 expression.

CONCLUSION

Antiapoptotic mechanisms and proliferation play an important role in the etiopathogenesis of pterygium. Furthermore, Bcl-2 expression may be important in pterygium recurrence.

Ocular Exposure to Particulate Matter and Development of Pterygium: A Case-Control Study

Background:

Formation of pterygium has been mainly attributed to exposure to the ultraviolet (UV) radiation. Other factors such as dry weather, wind exposure and microtrauma with dust particles, have been linked to development of pterygium.

Objective:

To determine the association between ocular exposure to particulate matter and development of pterygium.

Methods:

This case-control study was conducted in a company dedicated to the production and marketing of toilets. We included a total of 90 cases identified in November 2013 and 184 controls. The diagnosis of pterygium was based on clinical examination. Variables studied included age and job tenure of the participants. Logistic regression analysis was used to assess the effect of exposure on developing pterygium.

Results:

All study participants were male. The mean age of the cases and controls was 39.9 (SD 9.5) and 37.8 (SD 7.3) years, respectively. 115 (42%) of the participants had a job tenure of 5–8 years. The percentages of cases and controls exposed to particulate matter were 31.1% (n=28) and 30.4% (n=56), respectively (OR 1.08, 95% CI 0.61 to 1.91).

Conclusion:

We could not observe any association between ocular exposure to particulate matter and development of pterygium.

Amniotic Membrane Grafts to Reduce Pterygium Recurrence

PURPOSE

To demonstrate the long-term outcome of pterygium surgery with adjunctive amniotic membrane transplantation (AMT) and intraoperative mitomycin C (MMC) in a large case series.

METHODS

Medical records were retrieved for this noncomparative retrospective study of all patients who had pterygium excision with adjunctive AMT and intraoperative MMC, from October 2010 to June 2016 with at least 6 months of follow-up.

RESULTS

There were a total of 556 eyes of 535 patients (291 males and 244 females) with average age of 51.9 ± 13 years who had pterygium excision (527 primary and 29 recurrent). For an average follow-up period of 17.3 ± 0.8 months (range 6-74 months), corneal recurrence occurred in 20 eyes (3.6%) and conjunctival recurrence in 12 (2.2%) in a total of 32 eyes (5.8%). Eleven eyes (2%) underwent reoperation. Other complications included granuloma (0.5%), diplopia (1.1%), and steroid-induced ocular hypertension (4.3%).

CONCLUSIONS

Adjunctive use of AMT and short exposure of MMC can reduce recurrence after pterygium surgery. The procedure is less tedious and less time consuming, resulting in early recovery while saving the conjunctiva for future surgeries.

Expression of p53 Protein in Pterygium

Purpose

The pathogenesis of pterygium is still not completely understood and many environmental factors, including ultraviolet (UV) radiation, play an important role in its etiology. Chronic exposure to UV radiation causes mutations in the p53 tumor suppressor gene, eventually leading to tumor formation. We analyzed the immunohistochemical expression of p53 proteins in pterygial tissues to determine the role of the p53 tumor suppressor gene in the development of pterygium.

Methods

Pterygial specimens were studied immunohistochemically using antibodies against p53 protein.

Results

Out of 38 specimens studied, 35 (92.1%) had conjunctival epithelial cells without p53 specific nuclear staining. Only three specimens (7.9%) had a few p53 stained cells. The role of UV radiation in the pathogenesis of pterygium is supported by epidemiological, geographical and microscopic findings. However, our results are not consistent with these data on a genetic basis.

Conclusions

We conclude that defective p53 tumor suppressor gene function seems to have no role in the pathogenesis of pterygium.

A mathematical approach to human pterygium shape

PURPOSE

Pterygium is a common lesion affecting the population in countries with high levels of ultraviolet exposure. The final shape of a pterygium is the result of a growth pattern, which remains poorly understood. This manuscript provides a mathematical analysis as a tool to determine the shape of human pterygia.

MATERIALS AND METHODS

Eighteen patients, all affected by nasal unilateral pterygia, were randomly selected from our patient database independently of sex, origin, or race. We included all primary or recurrent pterygia with signs of proliferation, dry eye, and induction of astigmatism. Pseudopterygia were excluded from this study. Pterygia were outlined and analyzed mathematically using a Cartesian coordinate system with two axes (X, Y) and five accurate landmarks of the pterygium.

RESULTS

In 13 patients (72%), the shape of the pterygia was hyperbolic and in five patients (28%), the shape was rather elliptical.

CONCLUSION

This analysis gives a highly accurate mathematical description of the shape of human pterygia. This might help to better assess the clinical results and outcome of the great variety of therapeutic approaches concerning these lesions.

The role of ultraviolet radiation in the pathogenesis of pterygia (Review)

Pterygium is a common ophthalmic disease affecting humans only. Extensive epidemiological data have demonstrated a causative effect of chronic ultraviolet (UV) radiation on pterygia. Progress has been made in determining the origin of pterygia, their nasal predilection and wing‑shaped appearance, and the roles of UV radiation in the initiation and the development of pterygia. In the present review, the current understanding of the involvement of UV radiation in the pathogenesis of pterygia is summarized. This involvement includes the alteration of limbal stem cells and fibroblasts that contribute to the initiation of pterygia and the induction of various pro‑inflammatory cytokines, growth factors and matrix metalloproteinases that promote the progression of pterygia. Further elucidation of the roles of UV radiation in the pathogenesis of pterygia may help to encourage individuals at risk of developing pterygia to take preventive measures and aid researchers in the development of novel targeted therapeutic agents to treat pterygia.

Conjunctival metaplasia after pterygium excision and limbal autograft

PURPOSE

To investigate the changes of conjunctival epithelium in the pterygium and donor graft sites after pterygium excision and limbal conjunctival autograft.

METHODS

This study included 16 eyes of 15 patients who underwent pterygium excision and limbal conjunctival autograft. Epithelial impression cytology specimens of both the pterygium and donor graft were obtained preoperatively and at months 1, 3, and 6, at the pterygium and donor graft sites, respectively. In each specimen, changes in the conjunctival epithelium, including the nucleus-to-cytoplasm (N/C) ratio and goblet cell density (GCD), were evaluated. Morphologic changes in the cells and nuclei were also evaluated.

RESULTS

Preoperatively, both N/C ratio and GCD were significantly higher in specimens from the pterygium than in those from the donor site. At both sites, GCD decreased rapidly at 1 month after surgery and then gradually recovered. No significant difference in GCD was found between the two sites at 1, 3, and 6 months postoperatively. Although there was no significant difference in the N/C ratio at 1 and 3 months, the N/C ratio at the pterygium site was significantly greater than that at the donor site at 6 months. At 6 months postoperatively, changes suggesting squamous metaplasia, including elongation of the cells and pyknotic changes in the nuclei, were noted in five samples (31.3%) from the pterygium site but not in any of the samples obtained from the donor site.

CONCLUSIONS

Conjunctival epithelial metaplasia may return after pterygium removal, which may be associated with the high rate of pterygium recurrence.

Oxidant/antioxidant state in tissue of prymary and recurrent pterygium

BACKGROUND

Pterygium is a disorder of the ocular surface induced by chronic exposure to UV-light. Abundant data is available from patients with primary pterygium, but scarce from those with recurrent pterygium. The present study aimed to explore the oxidant/antioxidant status in tissue of primary and recurrent pterigium in men and women.

METHODS

Pathological tissue samples were taken during surgery on patients with primary and recurrent pterygium. Healthy conjunctive tissue samples were taken during cataract surgery. After homogenization of 77 tissue samples, evaluation was made of thiobarbituric reactive substances (TBARS), nitric oxide (NO), total antioxidant status (TAS) and the activity of the three main antioxidant enzymes: glutathione peroxidase, superoxide dismutase and catalase. Gender differences were evaluated.

RESULTS

Compared to the control group, in the primary pterygium group there was an increase in NO and TAS, and a tendency to a decrease of all antioxidant enzymes, indicating an increase in non-enzymatic antioxidant activity. Compared to the control group, in the recurrent pterygium group there was a significant decrease in the level of TAS and antioxidant enzymes. A high positive correlation was found between most of measured parameters within the control group and the recurrent pterygium group, but not within the primary pterygium group. Compared to men, a significant difference was observed in the elevated NO level and low TAS level of women in the prymary pterygium group.

CONCLUSIONS

The diminished antioxidant defense in the recurrent pterygium group, possibly determined mainly by decreased non-enzymatic activity, supports the idea that oxidative stress plays an important role in the recurrence of this disorder.

Ocular surface squamous neoplasia: a survey of changes in the standard of care from 2003 to 2012

PURPOSE

To evaluate the current standard of care of ophthalmologists who are likely to encounter ocular surface squamous neoplasia (OSSN) in their practices and to compare this with data gathered in 2003.

METHODS

Invitations to a web-based survey were sent to members of the Ocular Microbiology and Immunology Group. In addition, the survey was posted to the Cornea Society Listserv, Keranet. The survey contained questions regarding the surgical and medical management of OSSN and postcare follow-up. The results of this survey were compared with the results of a 2003 survey, where possible, to identify the areas of change in the standard of care.

RESULTS

Eighty-one ophthalmologists participated in the survey. Seventy-nine percent of the responders thought that there was enough evidence for topical monotherapy in OSSN, but only 58% reported ever using topical agents as monotherapy. First-line topical therapy was interferon α2b (56%) followed by mitomycin C (MMC) (37%). A shift from surgical excision alone to excision followed by topical therapy was seen when comparing the 2012 survey to the 2003 survey. The preferred postexcision topical agent was MMC. Seventy-five percent of responders evaluate their patients every 2 to 4 months during the first 2 years.

CONCLUSIONS

Topical agents were being used more in 2012, either in combination with surgical excision or as monotherapy, compared with those used in 2003. Interferon has replaced MMC as the agent most used for topical monotherapy, possibly because of a favorable safety and tolerance profile. Prospective randomized trials are needed to better define the ideal practice patterns.

Differentiation and molecular profiling of human embryonic stem cell-derived corneal epithelial cells

It has been suggested that the isolation of scalable populations of limbal stem cells may lead to radical changes in ocular therapy. In particular, the derivation and transplantation of corneal stem cells from these populations may result in therapies providing clinical normality of the diseased or damaged cornea. Although feasible in theory, the lack of donor material in sufficient quantity and quality currently limits such a strategy. A potential scalable source of corneal cells could be derived from pluripotent stem cells (PSCs). We developed an in vitro and serum-free corneal differentiation model which displays significant promise. Our stepwise differentiation model was designed with reference to development and gave rise to cells which displayed similarities to epithelial progenitor cells which can be specified to cells displaying a corneal epithelial phenotype. We believe our approach is novel, provides a robust model of human development and in the future, may facilitate the generation of corneal epithelial cells that are suitable for clinical use. Additionally, we demonstrate that following continued cell culture, stem cell-derived corneal epithelial cells undergo transdifferentiation and exhibit squamous metaplasia and therefore, also offer an in vitro model of disease.

The pathologic characteristics of pingueculae on autofluorescence images

PURPOSE

To analyze the autofluorescence (AF) properties of pinguecula using cobalt-blue and yellow filters and to investigate the nature and pathogenesis of pingueculae using histochemical and immunohistochemical staining.

METHODS

Fifty pingueculae in 40 patients were included in this study. AF of the pingueculae was observed and analyzed using a cobalt-blue filter with an additional yellow filter on a slit-lamp. Hematoxylin-eosin and immunohistochemical stainings were performed on surgical specimens of pingueculae that were prepared from each patient. Immunohistochemical staining included Congo red, Oil Red O, periodic acid-Schiff (PAS), Masson's trichrome, transglutaminase-2 (TG-2), mesenchymal stem cell markers CD29 (β-1-integrin), and CD34.

RESULTS

AF images revealed hyper-AF in the pinguecula area. The AF lesions of pingueculae showed superficial punctuate erosions and avascular lesions. Deposition of eosinophilic and amorphous materials in the subepithelial layer of the pinguecula were observed on hematoxylin-eosin staining. Historeactivities to Congo red, PAS, Oil Red O, alcian blue, and Masson's trichrome were not detected, but immunoreactivities to CD29, CD34, and TG-2 were detected in the pingueculae with AF. However, CD29, CD34, and TG-2 were not detected in the pingueculae without AF.

CONCLUSIONS

The AF of pingueculae may be related to CD29, CD34, and TG-2. We suggest that pingueculae with AF have a different pathogenesis compared to pingueculae without AF.

Chronic inflammatory cells and damaged limbal cells in pterygium

BACKGROUND

Chronic inflammation in pterygium occurrence has not been explained. Whether damaged limbal basal epithelial cells are associated with pterygium occurrence in black Africans is not clear.

OBJECTIVE

To explain chronic inflammation in pterygium, and to clarify whether damaged limbal basal epithelial cells were associated with pterygium occurrence in black Africans.

METHODS

Chronic inflammatory changes and damaged limbal basal epithelial cells were assessed in 59 samples.

RESULTS

Chronic inflammatory cells were present in 59 pterygia. Inflammatory cell count in 5 (27.8%) of 18 small pterygia was >200 (high) while in 22 (53.7%) of 41 large growths was <200 (low); p = 0.25. The proportion of pterygia with high counts tended to increase with pterygium extent. Twenty (33.9%) of 59 pterygia recurred after surgery. Ten (50%) of 20 samples had high cell counts and 10 (50%), low counts; p = 0.40. P53 expression was detected in 11 (18.6%) of 59 pterygium samples and 5 (71.4%) of 7 controls; p = 0.007. MMP 1 staining was present in 14 (23.7%) of 59 sections and 5 (71.4%) of 7 controls; p = 0.02. MMP2 in 16 (27.1%) cases and 5 (71.4%) controls; p = 0.03. MMP3 was overexpressed in 16 (27.1%) of 59 cases and 5 (71.4%) controls; p = 0.03.

CONCLUSIONS

Mild chronic inflammation has a tendency to be more frequent than severe inflammation in pterygia. It is clear that damaged limbal basal epithelial cells are unlikely to be related to pterygium occurrence.

Oral doxycycline reduces pterygium lesions; results from a double blind, randomized, placebo controlled clinical trial

PURPOSE

To determine whether oral doxycycline treatment reduces pterygium lesions.

DESIGN

Double blind, randomized, placebo controlled clinical trial.

PARTICIPANTS

98 adult patients with primary pterygium.

METHODS

Patients were randomly assigned to receive 100 mg oral doxycycline twice a day (49 subjects), or placebo (49 subjects), for 30 days. Photographs of the lesion were taken at the time of recruitment and at the end of the treatment. Follow-up sessions were performed 6 and 12 months post-treatment. Statistical analyses for both continuous and categorical variables were applied. p values of less than 0.05 were considered to indicate statistical significance.

MAIN OUTCOME MEASURES

The primary endpoint was the change in lesion size after 30 days of treatment.

RESULTS

The primary endpoint was not met for the whole population but subgroup analysis showed that doxycycline was effective in patients of Caucasian origin while other ethnicities, mostly Hispanic, did not respond to the treatment. Moreover, there was a correlation between age and better response (p = 0.003). Adverse events were uncommon, mild, and in agreement with previous reports on short doxycycline treatments.

CONCLUSIONS

Oral doxycycline was superior to placebo for the treatment of primary pterygia in older Caucasian patients. These findings support the use of doxycycline for pterygium treatment in particular populations.

TRIAL REGISTRATION

European Union Clinical Trials Register EudraCT 2008-007178-39.

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

Background

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

Purpose

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

Patients and methods

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

Results

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

Conclusion

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

The effect of topical 0.05% cyclosporine on recurrence following pterygium surgery

PURPOSE

To investigate the role of postoperative topical 0.05% cyclosporine A (CsA) eye drops (Restasis(®), Allergan Pharmaceutical) in the prevention of recurrence among patients with primary pterygium treated with bare-sclera technique.

METHODS

In this prospective randomized controlled study, 36 eyes (34 patients) with primary pterygium were randomized into two groups: Group I comprised 18 eyes (18 patients), and Group II comprised 18 eyes (16 patients). Bare sclera technique was performed in both groups. In Group I, 0.05% CsA was administered postoperatively at 6-hour intervals for 6 months, and Group II did not receive any cyclosporine treatment. The patients were assessed for recurrence, side effects, and complications at postoperative 1 and 7 days as well as each month during the following year. Conjunctival advances which showed a limbus higher than 1 mm were recognized as recurrence.

RESULTS

Recurrence occurred in four patients (22.2%) in Group I and in eight (44.4%) patients in Group II.

CONCLUSION

Postoperative application of low-dose CsA can be effective for preventing recurrences after primary pterygium surgery.

Ophthalmic pterygium: a stem cell disorder with premalignant features

Pterygia are common ocular surface lesions thought to originate from limbal stem cells altered by chronic UV exposure. Traditionally regarded as a degenerative condition, pterygia also display tumor-like features, such as a propensity to invade normal tissue and high recurrence rates following resection, and may coexist with secondary premalignant lesions. This study was initiated to determine the rate of concurrent ocular surface diseases in patients with pterygia recruited from the practice of a single surgeon operating in a Sydney metropolitan hospital. One hundred pterygium specimens were histopathologically reviewed and selected cases were immunohistochemically assessed to confirm diagnosis. Along with previously documented typical features including epithelial proliferation, goblet cell hyperplasia, angiogenesis, inflammation, elastosis, stromal plaques, and Bowman's membrane dissolution, we identified five cases of ocular surface squamous neoplasia, six cases of primary acquired melanosis, two compound nevi (one suspect invasive melanoma), and one dermoid-like lesion. In 18 specimens, clusters of basal epithelial cells that coexpressed cytokeratin-15/-19 and p63-α were identified at the head of the pterygium, coinciding with clinical observation of Fuchs' flecks. Our data show that significant preneoplastic lesions may be associated with pterygium and that all excised pterygia should undergo histological examination. The presence of p63-α-positive epithelial cell clusters supports the hypothesis that pterygia develop from limbal epithelial progenitors.

[Evaluation of topical vasoconstrictors in pterygium surgery and their role in reducing intraoperative bleeding]

OBJECTIVE

To reduce vascularisation before surgery through the application of topical vasoconstrictors, decreases the rate of intraoperative bleeding, improves the dynamics of the surgery and reduces the difficulty in surgical performance.

METHODS

Only patients with primary pterygium were included in the study. A prospective randomized clinical trial was designed to compare intraoperative bleeding, need for cauterization and surgical time a group that was administered phenylephrine. preoperatively and one which did not receive it. The sample was divided into two groups: 1st (n=27) received topical phenylephrine (F) 0.1 ml (10%), twice in 5 minutes before surgery. 2nd (n=30) did not receive phenylephrine (NoF). The technique was similar in both groups using conjunctival autograft suturing. In both groups, the subconjunctival aneasthesia was performed with 0.5% bupivacaine hydrochloride with epinephrine 1:200,000.

RESULTS

A total of 57 patients were included in the study. The mean operation time for group F was 15.57 minutes (SD: 1.8 min) and the NoF group 16.51 min (SD to 1.82 min, P=.057). In the group F, it was necessary to use diathermy in 2 patients (7.4%) and in the NoF group cauterisation was used in 14 patients (46.7%, Chi-Square=10.848, P=.001. There is a relative risk 6.3 (95% CI 1.57 - 25.27) times greater than having to cauterise without phenylephrine when used phenylephrine.

CONCLUSIONS

The use of topical vasconstrictors prior to pterygium surgery reduces the rate of bleeding and the time of surgery.

What a study of pterygia teaches us about the cornea? Molecular mechanisms of formation

Experiments were carried out in the early 1990s to investigate the cell types involved in a pterygium and to determine a possible mechanism of formation. Our first experiments used monoclonal antibodies to keratins and an associated protein (vimentin), to look at the cells that compose a pterygium. These experiments demonstrated that a pterygium is the result of an abnormal limbal basal epithelial stem cell that moves onto Bowman's layer and brings about the dissolution of this layer. More importantly, these data showed that the clear corneal epithelial cells in front of the pterygium also contained these abnormal limbal cells, which we named the pterygium cell. This demonstrated that when a pterygium is removed, a wide area of what appears to be normal epithelium must be removed to inhibit reoccurrence of the growth. Later experiments using expressed sequence tag analysis of an un-normalized unamplified complementary DNA library from surgically removed pterygia were compared with normal cornea and confirmed the role of the epithelial cells in this growth. The gene expression studies also showed that genes involved in cellular migration are stimulated, and this led to studies on polyamine analogs as inhibitors of pterygial migration. Immunohistochemical studies with antibodies to matrix metalloproteinases (MMPs) showed that it is the pterygium cell that produces the MMPs that dissolve Bowman's layer resulting in the growth stimulation of stromal fibroblasts. This led to experiments on the use of MMP inhibitors to inhibit the growth of pterygia.

Prevalence of pinguecula and pterygium in a general population in Spain

PURPOSE

To determine the prevalence of pinguecula and pterygium and to investigate their associations in a general adult population in North-Western Spain.

METHODS

An age-stratified random sample of 1155 subjects ≥ 40 years was selected in O Salnés (Spain). From 937 eligible subjects, 619 (66.1%) participated (mean age (SD): 63.4 (14.5) years, range: 40-96 years, 37.0% males). An interview to collect history of systemic diseases and lifestyle details and a comprehensive ophthalmic evaluation in which pinguecula and pterygium were recorded was carried out. The prevalence of pinguecula and pterygium and their relationship with lifestyle factors and ocular and systemic diseases was investigated.

RESULTS

The prevalence of pinguecula was 47.9% (95% confidence interval (CI): 43.9-51.9). This prevalence increased significantly with aging (P = 0.002) and was higher in men (56.4%; 95% CI: 50.0-62.7) than in women (42.7%; 95% CI: 37.8-47.8) (P=0.001). The prevalence of pterygium was 5.9% (95% CI: 4.3-7.9). This prevalence also increased significantly with aging (P = 0.005) and was 4.8% (95% CI: 2.6-8.4) in men and 6.5% (95% CI: 4.5-9.3) in women (P = 0.346). After controlling for age and sex, pinguecula was associated with alcohol intake (adjusted odds ratio (OR(a)): 3.08; 95% CI: 1.60-5.95), pterygium with fluorescein staining (OR(a): 2.64; 95% CI: 1.08-6.46) and both disorders with outer activity (OR(a): 2.07; 95% CI: 1.36-3.15 and 2.28; 95% CI: 1.04-4.98, respectively).

CONCLUSIONS

Pinguecula is far more common than pterygium. Alcohol consumption is strongly associated with pinguecula. Fluorescein staining is highly prevalent in subjects with pterygium. Both disorders increase with age and are associated with outer activity.

Doxycycline's effect on ocular angiogenesis: an in vivo analysis

PURPOSE

To determine the in vivo effect of doxycycline on choroidal angiogenesis and pterygium growth by using a choroidal neovascular (CNV) murine model, a directed in vivo angiogenesis assay (DIVAA) and a pterygium murine model.

DESIGN

Experimental study.

PARTICIPANTS

Three murine models were investigated with 4 mice minimum per group and 22 maximum per group.

METHODS

Mice received water with or without doxycycline. For the CNV, the neovascular lesion volume was determined in choroid-retinal pigment epithelial flat mounts using confocal microscopy 7 days after laser induction. For DIVAA, silicone capsules containing 10,000 human pterygium epithelial cells were implanted in the flanks of mice subcutaneously. After 11 days, neovascularization (NV) was quantified using spectrofluorometry after murine tail-vein injection of fluorescein isothiocyanate-labeled dextran. A pterygium epithelial cell model was developed by injecting 10,000 human pterygium epithelial cells in the nasal subconjunctival space in athymic nude mice. Doxycycline was started on day 6 at 50 mg/kg per day; corneal lesions that resulted from the injections were compared at days 6 and 15.

MAIN OUTCOME MEASURES

The Student t-test was used to evaluate the data for the CNV and DIVAA models and histologic preparations were used to evaluate pterygia lesions.

RESULTS

There was significantly less NV and lesion volume with doxycycline taken in drinking water versus plain water. With doxycycline treatment, the laser-induced CNV showed a maximal 66% decrease in choroidal blood vessel volume (P< or =0.008) and the DIVAA showed a 30% reduction of blood vessel growth and migration (P<0.004). Histologic preparations demonstrated that pterygium cell lesions regressed when mice were administered doxycycline for 9 days.

CONCLUSIONS

Doxycycline significantly inhibited angiogenesis in 3 murine models. The most dramatic effect was found in the CNV model followed by the pterygia epithelial cell DIVAA model. The anterior segment pterygium model also showed regression histologically. This suggests that doxycycline may be successful as an adjunctive treatment for CNV and pterygia in humans; clinical trials would be necessary to determine if there is a benefit.

Comparison of pterygium recurrence rates in Hispanic and white patients after primary excision and conjunctival autograft

PURPOSE

To evaluate the impact of Hispanic and white ethnicity on the recurrence rates of pterygia after primary excision and conjunctival autograft (CAG) in a southern California population.

METHODS

A retrospective case-control review comparing 15 Hispanic and 11 white patients with primary nasal pterygia was performed. All participants received pterygium excision with superior limbal CAG by 1 of 3 surgeons and postoperative topical steroids for 2 months. The main outcome measure was recurrence after surgery, defined as fibrovascular tissue over the corneoscleral limbus onto clear cornea in the area of previous pterygium excision.

RESULTS

Average duration of follow-up in the Hispanic and white groups were 9.3 +/- 9.8 months and 13.0 +/- 10.7 months, respectively (P = 0.39). During this follow-up period, there was a statistically significant difference in the pterygium recurrence rate between the Hispanic patients, 6 of 15 (40%), and the white patients, 0 of 11 (0%) (P = 0.02). The average time to recurrence was 3.4 +/- 1.1 months (range, 1.9-5.0). The difference in average age, male/female composition, and follow-up time between the Hispanic and white patient groups studied was not found to be statistically significant (P > 0.05).

CONCLUSION

Hispanic ethnicity is a potentially important risk factor for recurrence of primary pterygia treated with CAG.

Presence of human papillomavirus in pterygium in Taiwan

PURPOSE

To evaluate the prevalence and possible role of human papillomavirus (HPV) in the formation of pterygia in patients in Taiwan, a tropical country with high prevalence of pterygium.

METHODS

A total of 62 patients with 65 pterygia were retrospectively examined. Ten normal conjunctiva, 8 conjunctival nevi, and 2 malignant conjunctival melanomas served as controls. HPV detection and typing were accomplished using polymerase chain reaction amplification of the viral sequences. HPV-positive specimens underwent further investigation with fluorescence in situ hybridization. Clinical histories were recorded for each patient.

RESULTS

Based on polymerase chain reaction analysis, 2 of 65 pterygia harbored HPV type 18, and they were also fluorescence in situ hybridization positive. No conjunctival control had HPV. There was no statistically significant correlation between pterygium and the presence of HPV. The presence of HPV was not significantly different between primary and recurrent pterygia.

CONCLUSIONS

The limited presence of HPV DNA in pterygium does not conclude that HPV is necessary or acting alone in the formation of pterygium, but HPV may still be implicated to play a role in some pterygia in Taiwan.

Prevalence and risk factors of pterygium in a southwestern island of Japan: the Kumejima Study

PURPOSE

To determine the prevalence and risk factors for pterygium in a Japanese population aged 40 years or older on Kumejima Island, Japan.

DESIGN

Cross-sectional, population-based study.

METHODS

All residents of Kumejima Island, Japan, located in Southwestern Japan (Eastern longitude 126 degrees, 48 feet and Northern latitude 26 degrees, 20 feet), aged 40 years and older were asked to undergo a comprehensive questionnaire and ocular examination.

RESULTS

Of the 4,632 residents, 3,762 (81.2%) underwent the examination. The presence of pterygium could not be determined in 15 subjects. Of the 3,747 eligible subjects, 1,154 (30.8%; 95% confidence interval [CI], 29.3% to 32.3%) had pterygium in at least 1 eye and 491 subjects (13.1%; 95% CI, 12.1% to 14.3%) had pterygium in both eyes. In the logistic regression analysis, older age (P < .001), male gender (P = .024), hyperopic refraction (P = .001), lower intraocular pressure (P = .002), and outdoor job experience (P < .001) were independently associated with a higher risk of pterygium.

CONCLUSION

The prevalence of pterygium is 30.8% among adult Japanese aged 40 years and older in Kumejima. Older age, male gender, hyperopic refraction, lower intraocular pressure, and outdoor job history were independently associated with a higher risk of pterygium.

EphrinB2 and EphB4 expression in pterygia: new insights and preliminary results

OBJECTIVE

Pterygium is a growth of fibrovascular tissue onto the cornea, in which the mechanisms of cell proliferation and vascularization are unknown. The ephrin-Eph system, especially ephrinB2 and its receptor EphB4, has been shown to play an important role in tumor angiogenesis. EphrinB2 and EphB4 have also been reportedly involved in the pathogenesis of ocular angiogenesis. This study was designed to investigate the expression of ephrinB2 and its receptor EphB4 in pterygia.

DESIGN

Experimental study of the expression of ephrinB2 and its receptor EphB4 in pterygia.

PARTICIPANTS

Twenty-three primary pterygia, 5 recurrent pterygia, and 11 normal conjunctiva were studied.

METHODS

Immunohistochemistry studies were used to assess ephrinB2 and EphB4 protein expression levels and the tissue distribution in the samples.

RESULTS

EphrinB2 and EphB4 staining was present at a dense level in the total epithelium of the head portions of both primary and recurrent pterygial specimens, although just in the basal and parabasal layer of the epithelium of most of the normal conjunctivae.

CONCLUSIONS

EphrinB2 and EphB4 appear to be overexpressed in pterygium, and they may play important roles in its development.

The roles of T-lymphocyte subpopulations (CD4 and CD8), intercellular adhesion molecule-1 (ICAM-1), HLA-DR receptor, and mast cells in etiopathogenesis of pterygium

PURPOSE

The etiopathogenesis of pterygia is controversial. We wished to explore the effects of inflammatory cells and mediators such as T-lymphocyte subpopulations (CD4 and CD8), mast cells, intercellular adhesion molecule-1 (ICAM-1), and HLA-DR receptors on pterygium development.

METHODS

Immunohistochemical stainings were performed for T-lymphocyte subpopulations, mast cells, ICAM-1, and HLA-DR on sections of pterygium specimens. Nasal bulbar conjunctival specimens of patients undergoing cataract or vitrectomy operations were used for comparision. The mean number of mast cells/mm2 was calculated using an ocular grid, and the difference between the numbers derived from pterygium and from normal conjunctival sections was analyzed statistically using the Mann-Whitney U test. CD4 and CD8 lymphocytes in the epithelial and subepithelial regions, and ICAM-1 and HLA-DR expression on pterygium epithelium were compared qualitatively.

RESULTS

Increased CD4 and CD8 lymphocytic infiltration in pterygium sections was observed. Only occasional lymphocytes were detected in normal conjunctival sections. The CD4/CD8 ratio was 0.33 for pterygium epithelium and 1.34 for pterygium substantia propria. Increased HLA-DR and scattered ICAM-1 expression were also detected on pterygium epithelium, but not on the normal conjunctival epithelium. The difference in mast cell numbers between the pterygium and control groups was not statistically significant.

CONCLUSIONS

The detection of T-lymphocyte infiltration and ICAM-1 and HLA-DR expression in pterygium epithelium strongly supports the suggestion that cellular immunity plays an important role in pterygium formation. Pterygium epithelium also seems to participate actively in the augmentation of this inflammatory process by expressing ICAM-1 and HLA-DR molecules. Mast cells may participate in some stages or subtypes of pterygium during its development.

p53 expression in pterygium in two climatic regions in Turkey

Purpose:

To assess accumulation of p53 protein in samples of primary pterygium from people living in two different climatic regions in Turkey.

Materials and Methods:

Group 1 included 101 pterygium specimens from people in Adana located in southern Turkey. Group 2 included 39 pterygium specimens from people in Ankara, located in the middle of Turkey. Climatic conditions throughout the year are sunnier and warmer in Adana than they are in Ankara. The control group (Group 3) included 30 specimens of conjunctiva that had been excised during cataract surgery from 30 patients without pterygium. The pterygial specimens and control conjunctiva were studied by immunohistochemistry using antibodies against p53 protein. Pearson's chi-square test was used to compare the p53 immunoreactivity.

Results:

The p53 immunoreactivity in Groups 1 and 2 was greater than it was in the control group (P<0.001). There were no differences in p53 immunoreactivity between Groups 1 and 2 (P= 0.060).

Conclusion:

The p53 immunoreactivity was not correlated with ultraviolet irradiation exposure. The p53 immunoreactivity in our pterygium specimens suggests that pterygium could be a result of uncontrolled cell proliferation.