Impression cytology of pterygium

Conjunctival Autofluorescence and Cytological Changes in Pterygium

PURPOSE

The purpose of this study was to evaluate the presence and pattern of autofluorescence and its related cytological changes in pterygium.

METHODS

Eighty-six patients with unilateral pterygium and 76 controls were recruited. We graded pterygium, looked for autofluorescence, performed cytology of the nasal conjunctiva, repeated evaluation after 6 months, compared findings with controls, and assessed the progression of pterygium from photographs with the help of ImageJ software.

RESULTS

Autofluorescence was present in 51% of cases with pterygium. Autofluorescence at the leading edge (65.9%) was the predominant pattern seen. In total, 83.3% of grade 3 pterygia, 64.7% of grade 2 pterygia, and 28.9% of grade 1 pterygia (P value <0.0005) had autofluorescence. Impression cytology showed conjunctival epithelial cells in 60% of cases, significant squamous metaplasia in grade 3 pterygia (45%) compared with grade 2 pterygia (11.8%), and normal conjunctival epithelial cells in grade 1 pterygia (P value < 0.0005).

CONCLUSIONS

The presence and pattern of conjunctival autofluorescence and cytological changes, especially squamous metaplasia, are linked to the severity or grade of pterygium.

Pterygium-The Good, the Bad, and the Ugly

Pterygium is a multifaceted pathology that displays apparent conflicting characteristics: benign (e.g., self-limiting and superficial), bad (e.g., proliferative and potentially recurrent) and ugly (e.g., signs of preneoplastic transformation). The natural successive question is: why are we lacking reports showing that pterygium lesions become life-threatening through metastasis, especially since pterygium has considerable similarities with UV-related malignancies on the molecular level? In this review, we consider how our pathophysiological understanding of the benign pterygium pathology overlaps with ocular surface squamous neoplasia and skin cancer. The three UV-related disorders share the same initial insult (i.e., UV radiation) and responsive repair mechanisms to the ensuing (in)direct DNA damage. Their downstream apoptotic regulators and other cellular adaptations are remarkably alike. However, a complicating factor in understanding the fine line between the self-limiting nature of pterygium and the malignant transformation in other UV-related diseases is the prominent ambiguity in the pathological evaluation of pterygium biopsies. Features of preneoplastic transformation (i.e., dysplasia) are used to define normal cellular reactions (i.e., atypia and metaplasia) and vice versa. A uniform grading system could help in unraveling the true nature of this ancient disease and potentially help in identifying the earliest intervention point possible regarding the cellular switch that drives a cell’s fate towards cancer.

How to minimize pterygium recurrence rates: clinical perspectives

The main treatment for pterygium is surgical removal. However, pterygium surgery is concerned with high rates of postoperative recurrence. Predicting factors of recurrence are not fully understood, yet, but they probably depend on a multitude of patient-related, clinical, and/or surgical factors. Several adjuvant treatments have been proposed to reduce postoperative pterygium recurrence, including different antimetabolites, antiangiogenetic factors, and radiation therapy. The purpose of this review is to collect the current evidence regarding application and limits of different therapeutic approaches for preventing postoperative recurrence of pterygium, giving insights and perspectives for better management of this disease. In the light of the current evidence, pterygium surgery cannot disregard wound coverage with conjunctival autografting or rotational flap combined with adjuvant treatments. The rotational flap technique is associated with shorter surgical time rates and prevents graft displacement and necrosis, given its vascular pedicle. Amniotic membrane may still be reserved in case of great conjunctival defects or insufficient conjunctiva. Repeated subconjunctival antivascular endothelial growth factor injections can be considered as an effective and safe adjuvant treatment. Moreover, management of postoperative pain is crucial. Innovative treatment strategies will probably target different molecular pathways, considering recent findings regarding pterygium pathogenesis, to improve better understanding and develop universally shared guidelines. Great importance shall be dedicated to the identification of novel molecular biomarkers and favoring factors of recurrence, in order to achieve a customized surgical treatment for each patient and obtain maximal reduction of postoperative recurrence.

Adjuvant Use of Cyclosporine A in the Treatment of Primary Pterygium: A Systematic Review and Meta-Analysis

PURPOSE

To evaluate the efficacy and tolerability of cyclosporine A (CsA) as an adjuvant treatment for primary pterygium.

METHODS

A comprehensive literature search from 7 databases (EMBASE, ISI Web of Science, PubMed, and the Cochrane Library for studies published in English and VIP, Wan Fang, and CNKI for studies published in Chinese). For the recurrence rate, pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using a random-effects model. Tolerability estimates were measured by OR for adverse events.

RESULTS

A total of 7 studies meeting the inclusion criteria were included in this meta-analysis. Compared with the group with adjunctive CsA usage, the control group (no adjuvant use of CsA) showed a significantly increased risk of pterygium recurrence (OR = 2.71; 95% CI, 1.62-4.54). No obvious heterogeneity was detected in the included studies. Subgroup analysis showed that adjuvant use of CsA with pterygium excision alone resulted in a significantly lower frequency of recurrence than was seen in the group without adjuvant use of CsA (OR = 3.16; 95% CI, 1.18-8.84). However, there is no significant difference in pterygium recurrence between the subgroup (CsA + pterygium excision + limbal conjunctival autograft or flap rotation) and the subgroup without adjunctive CsA usage (pterygium excision + limbal conjunctival autograft or flap rotation).

CONCLUSIONS

This meta-analysis suggests that adjuvant use of CsA can significantly reduce the risk of pterygium recurrence compared with pterygium excision alone, whereas adjuvant use of CsA may not reduce the risk of pterygium recurrence in terms of pterygium excision + limbal conjunctival autograft or conjunctival flap rotation.

Ophthalmologic Features of Progeria

PURPOSE

To establish the natural history of ophthalmic characteristics in Progeria patients and to determine incidence of ocular manifestations.

DESIGN

Retrospective case series of patients with Progeria who were seen between 2007 and 2016.

METHODS

Setting: Tertiary-care academic center.

PATIENT POPULATION

Fourteen patients (28 eyes) with Hutchinson-Gilford Progeria syndrome were included for statistical analysis from a total of 84 patients who have been enrolled in clinical trials for Progeria at Boston Children's Hospital. Clinical treatment trial patients who were not seen at the Department of Ophthalmology at our hospital, but for whom we had detailed clinical ophthalmologic records, were also included. This essentially represents an estimated 20% of the world's known patients with Progeria. Interventions or Observation Procedures: Complete ophthalmic examination.

MAIN OUTCOME MEASURES

Visual acuity, stereoacuity, refraction, clinical findings of slit-lamp and dilated fundus examinations.

RESULTS

Ophthalmic manifestations noted were hyperopia and signs of ocular surface disease owing to nocturnal lagophthalmos and exposure keratopathy. Additional ophthalmic manifestations included reduced brow hair, madarosis, and reduced accommodation. Most patients had relatively good acuity; however, advanced ophthalmic disease was associated with reduced acuity.

CONCLUSIONS

Children with Progeria are at risk for serious ophthalmic complications owing to ocular surface disease. Children with Progeria should have an ophthalmic evaluation at the time of diagnosis and at least yearly after that. Aggressive ocular surface lubrication is recommended, including the use of tape tarsorrhaphy at night.

Stromal cell derived factor-1, CXCR4 and CXCR7 gene transcripts in pterygia

PURPOSE

Pterygium is a pathologic process with angiogenic and tumor cell like characteristics. Chemokine and chemokine receptors may contribute to the formation and growth of pterygia. The aim of this study was to assess the expression of stromal cell derived factor (SDF)-1, as an angiogenic chemokine, and its receptors, CXCR4 and CXCR7, gene transcripts in pterygia.

METHODS

RNA was extracted from tissue samples of 33 patients with primary pterygium and 35 volunteers with conjunctiva as the control group. Then the mRNA expression of SDF-1, CXCR4, and CXCR7 was assessed through quantitative Real Time PCR method using appropriate primers.

RESULTS

SDF-1 and both receptors transcripts had significantly higher expression in pterygia samples compared to the control group (P < 0.05). The ratio of CXCR7 transcript expression to CXCR4 was 26.4 in patients while it was 11 in controls.

CONCLUSION

As SDF-1 and its receptors, CXCR4 and CXCR7, were up-regulated in pterygia, SDF-1/CXCR4/CXCR7 axis may contribute to pterygium formation which can be possibly restrained by down-regulating this signaling pathway.

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.

Expression of CREB in primary pterygium and correlation with cyclin D1, ki-67, MMP7, p53, p63, Survivin and Vimentin

AIM

Ultraviolet (UV) B irradiation induces gene expression that leads to skin cancer. Among the transcription factors induced by UVB radiation exposure, the cyclic AMP response element-binding protein (CREB) is significant. Since several factors downstream of CREB signaling are known to be involved in pterygium pathogenesis, we investigated CREB expression in pterygial and human conjunctival tissues to evaluate if a similar expression pattern is present. Moreover, we analyzed the correlation with CREB expression and other known pterygium markers.

METHODS

Primary pterygium samples and normal bulbar conjunctivas surgically removed were analyzed. Formalin-fixed, paraffin-embedded tissues were stained by immunohistochemistry with anti-CREB, anti-vimentin, anti-ki-67, anti-survivin, anti-MMP7, anti-p63, anti-cyclin D1, or anti-p53 antibodies.

RESULTS

94.4% of pterygium samples were positive for CREB with a significant difference compared to the control group (p = 0.002). The staining was localized in the epithelium and absent in the stroma. An increased expression was found for cyclin D1 (p = 0.019), ki-67 (p = 0.005), vimentin (p = 0.003), survivin (p < 0.001), p63 (p = 0.003), and MMP7 (p = 0.002). CREB expression showed a significant correlation with cyclin D1 (ρ = 0.49; p = 0.035), ki-67 (ρ = 0.61; p = 0.007), and p53 (ρ = 0.57; p = 0.013) in pterygium.

CONCLUSIONS

These results permit to hypothesize that CREB is involved in pterygium pathogenesis. Since various molecules have been discovered to inhibit CREB, these data could be of interest for pterygium treatment.

Effects of tear hyperosmolarity on conjunctival cells in mild to moderate dry eye

PURPOSE

To analyze the effects of tear hyperosmolarity on conjunctival cells in mild to moderate dry eye.

METHODS

Sixty-eight subjects (35 females and 33 males, mean age 43, S.D. 20.3, range 18-87 years) with symptoms of dry eye were enrolled in the study. Patients with severe dry eye or any other condition that induces ocular inflammation were excluded. The sample was divided into two groups according to the tear osmolarity cut-off value of 308 mOsmol L(-1) measured in the right eye of each patient. Impression cytology of the temporal interpalpebral conjunctiva was performed and goblet cell density, nucleus diameter, cytoplasm diameter and nucleus/cytoplasm ratio of epithelial cells quantitatively assessed. A battery of tear tests (ferning test, tear break-up time and Schirmer I test) was also carried out in order to more completely describe the groups and understand the process. Analysis of variance (anova) was applied to establish cytological and tear differences between hyperosmolar and normal tear osmolarity eyes. Pearson's correlation was calculated between the cytological variables and tear osmolarity.

RESULTS

The normal tear osmolarity group included patients with symptoms of dry eye, grade 1-2 of squamous metaplasia, and a number of positive tear signs of dry eye ranging between 0 and 3. The hyperosmolar tear group included patients with symptoms of dry eye, grade 1-2 of squamous metaplasia with significantly lower values of nucleus diameter (F(1,66) = 4.3, p = 0.040), and a number of positive tear signs of dry eye ranging between 1 (hyperosmolar tear) and 4. Mean reflex secretion of tears was clearly normal in both groups but significantly lower (F(1,66) = 7.2, p = 0.009) in the hyperosmolar tear group. Significant correlations were established for tear osmolarity and goblet cell density (r(33) = 0.45, p = 0.006) and nucleus/cytoplasm ratio (r(33) = -0.44, p = 0.009) in the normal tear osmolarity group but not in the hyperosmolar tear group.

CONCLUSIONS

Mild to moderate hyperosmolar tear conditions seem to lead to an initial reduction of the conjunctival cell nucleus before the cytoplasm diameter showed a clear tendency to enlarge. The relationship between tear osmolarity and conjunctival cell characteristics seems to be linear only in the normal tear osmolarity group. These results also provide a plausible link between lower reflex secretion of tears and hyperosmolarity.

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.

Increased oxidative DNA damage, 8-hydroxydeoxy- guanosine, in human pterygium

PURPOSE

Chronic exposure to ultraviolet (UV) light is a widely accepted aetiological factor in the development of pterygium. UV radiation may induce production of reactive oxygen species via photosensitized oxidation, thus causing oxidative damage. This study was conducted to test the hypothesis that oxidative damage to DNA is increased in pterygium.

METHODS

Immunohistochemical analysis employing a monoclonal antibody specific for 8-hydroxy-2'-deoxyguanosine (8-OHdG), a ubiquitous maker of oxidative stress, was performed in three patients with primary pterygium. The levels of 8-OHdG in DNA isolated from the other 29 pterygium specimens and their adjacent normal conjunctival tissues were determined using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Immunohistochemistry of 8-OHdG showed a distinct pattern of more extensive and intense staining in the nuclei of pterygium tissue compared with that in their adjacent normal conjunctiva. ELISA also revealed that the average level of 8-OHdG in the pterygium tissues was 4.7-fold higher than that of the corresponding normal conjunctiva (P<0.001).

CONCLUSIONS

The increased levels of 8-OHdG in the pterygium tissues indicate that oxidative stress could play a role in the development of pterygium. These findings provide new information to better understand the pathogenesis of pterygium and are useful in the prevention and treatment of this disease.

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

Pterygium is a common ocular surface disease apparently only observed in humans. Chronic UV exposure is a widely accepted aetiological factor in the pathogenesis of this disease and this concept is supported by epidemiological data, ray tracing models and histopathological changes that share common features with UV damaged skin. The mechanism(s) of pterygium formation is incompletely understood. Recent data have provided evidence implicating a genetic component, anti-apoptotic mechanisms, cytokines, growth factors, extracellular matrix remodelling (through the actions of matrix metalloproteinases), immunological mechanisms and viral infections in the pathogenesis of this disease. In this review, the current knowledge on pterygium pathogenesis is summarised, highlighting recent developments. In addition, we provide novel data further demonstrating the complexity of this intriguing disease.