Immunohistochemical localization of advanced glycation end products in pinguecula

The Relationship between Pinguecula and Diabetes Mellitus: A Comparative Cross-Sectional Study

Purpose

To assess the relationship between diabetes mellitus (DM) and the presence of pinguecula and to identify other risk factors associated with pinguecula in patients attending the eye clinic at two tertiary university hospitals in Jordan.

Methods

This was a comparative cross-sectional hospital-based study of 241 consecutive patients (122 patients with DM and 119 patients with no diabetes). All patients underwent complete ophthalmic examination, and data were collected regarding age, sex, occupational activity, presence and grade of pinguecula, glycosylated hemoglobin (HbA1c), and presence of diabetic retinopathy.

Results

The mean (standard deviation, SD) ages of the DM and non-DM groups were 59.5 (10.8) years and 59.0 (11.6) years (p-value = 0.729), respectively. There was no significant difference in the prevalence of pinguecula between the diabetic and nondiabetic groups (66.4% vs. 66.5%, p = 0.998). Multivariate logistic regression analysis revealed that only outdoor occupational activity (OR = 5.16, 95% CI: 1.98-13.44, p = 0.001) was associated with increased prevalence of pinguecula. DM was not significantly associated with pinguecula (OR = 0.96, 95% confidence interval (CI): 0.55-1.67, p = 0.873). Neither age nor sex were significantly associated with pinguecula (p-value = 0.808, p-value = 0.390), respectively.

Conclusion

DM was not significantly associated with the development of pinguecula in this Jordanian population. The prevalence of pinguecula was significantly associated with an outdoor occupational activity.

Immunohistochemical localization of d ‐ β ‐aspartic acid in congenital and acquired middle ear cholesteatoma

Objective/Hypothesis

Middle ear cholesteatoma is characterized by abnormal growth of the keratinizing squamous epithelium of the temporal bone. d‐β‐aspartic acid is the major isomer of d‐aspartic acid found in elderly tissue. We assessed the immunoreactivity to k‐β‐aspartic acid of congenital and acquired middle ear cholesteatomas.

Study Design

Case–control studies.

Material and Methods

Tissue samples were collected from 21 patients comprising 21 ears with congenital middle ear cholesteatoma and 26 patients comprising 29 ears with acquired type. Their clinical and histopathological features were investigated. We divided the middle ear cholesteatoma samples into three layers: the perimatrix, matrix, and cystic contents. The patterns of immunoreactivity to d‐β‐aspartic acid expression were then assessed immunohistochemically.

Results

Two patterns of immunoreactivity to d‐β‐aspartic acid were detected in middle ear cholesteatoma: infiltrative and diffuse. In congenital middle ear cholesteatoma, d‐β‐aspartic acid expression was observed throughout all the layers (perimatrix, matrix, and cystic contents), and immunoreactivity to d‐β‐aspartic acid was dramatically strong in all layers. The expression levels of d‐β‐aspartic acid to the cystic content and perimatrix were significantly higher in congenital middle ear cholesteatoma than in the acquired type.

Conclusions

This study showed the expression levels of d‐β‐aspartic acid in middle ear cholesteatoma to differ significantly between congenital and acquired middle ear cholesteatoma. Our results indicate that overexpression of d‐β‐aspartic acid is likely to be involved in the pathogenesis of cholesteatoma, and we speculate that d‐β‐aspartic acid could be a novel biomarker for, and a therapeutic target in, congenital and acquired middle ear cholesteatoma.

Level of Evidence

4

Clinical Features of Pingueculitis Revealed by Anterior Segment Optical Coherence Tomography Findings

PURPOSE

To investigate clinical features and treatment outcomes of pingueculitis with morphological assessments using anterior segment optical coherence tomography (AS-OCT).

METHODS

In this retrospective observational study, we examined 22 eyes of 22 patients with pingueculitis. All patients were treated with the same 2-week course of prednisolone acetate 1% drops four times per day. The clinical parameters evaluated were surface dimensions determined by slitlamp biomicroscopy, cross-sectional dimensions determined by AS-OCT, and symptom scores determined by patient surveys. Pretreatment and 1-month posttreatment values were compared with Wilcoxon signed-rank tests. Patients were followed up to 1 year after treatment.

RESULTS

Twenty-two eyes from 22 patients (4 men and 18 women) with an average age of 37.7±8.8 (range, 27-57) years and an average duration of symptoms of 22 (range, 5-60) days were included. The average follow-up period was 14.7±0.8 (range, 12-22) months. Mean pretreatment horizontal length, vertical length, conjunctival thickness, and cross-sectional area were 2.4±0.69 mm, 2.0±0.6 mm, 1.82±0.60 μm, and 5.14±2.05 mm, respectively. Mean posttreatment horizontal length, vertical length, conjunctival thickness, and area were 1.93±0.5 mm, 1.52±0.6 mm, 1.03±0.46 μm, and 2.33±0.83 mm, respectively. Mean pretreatment and posttreatment dry eye symptom scores were 3.27±0.77 and 1.13±0.38, respectively. The median pretreatment and posttreatment changes were statistically significant by Wilcoxon signed-rank tests for horizontal length (P<0.001), vertical length (P<0.001), conjunctival thickness (P=0.003), cross-sectional area (P=0.003), and dry eye symptom scores (P<0.001).

CONCLUSION

Anterior segment optical coherence tomography allows the quantification of differences in the pingueculitis measurements before and after treatment. In this retrospective study, a short course of topical steroids effectively treated the inflammation in a sustained manner. Anterior segment optical coherence tomography demonstrated significant reduction in the thickness and cross-sectional area of the pinguecula and a conversion back to a homogeneous conjunctival stroma.

A novel role for CRIM1 in the corneal response to UV and pterygium development

Pterygium is a pathological proliferative condition of the ocular surface, characterised by formation of a highly vascularised, fibrous tissue arising from the limbus that invades the central cornea leading to visual disturbance and, if untreated, blindness. Whilst chronic ultraviolet (UV) light exposure plays a major role in its pathogenesis, higher susceptibility to pterygium is observed in some families, suggesting a genetic component. In this study, a Northern Irish family affected by pterygium but reporting little direct exposure to UV was identified carrying a missense variant in CRIM1 NM_016441.2: c.1235 A > C (H412P) through whole-exome sequencing and subsequent analysis. CRIM1 is expressed in the developing eye, adult cornea and conjunctiva, having a role in cell differentiation and migration but also in angiogenesis, all processes involved in pterygium formation. We demonstrate elevated CRIM1 expression in pterygium tissue from additional individual Northern Irish patients compared to unaffected conjunctival controls. UV irradiation of HCE-S cells resulted in an increase in ERK phosphorylation and CRIM1 expression, the latter further elevated by the addition of the MEK1/2 inhibitor, U0126. Conversely, siRNA knockdown of CRIM1 led to decreased UV-induced ERK phosphorylation and increased BCL2 expression. Transient expression of the mutant H412P CRIM1 in corneal epithelial HCE-S cells showed that, unlike wild-type CRIM1, it was unable to reduce the cell proliferation, increased ERK phosphorylation and apoptosis induced through a decrease of BCL2 expression levels. We propose here a series of intracellular events where CRIM1 regulation of the ERK pathway prevents UV-induced cell proliferation and may play an important role in the in the pathogenesis of pterygium.

Resolution of pinguecula-related dry eye disease after argon laser photocoagulation

Purpose

To describe an unusual case of unilateral, chronic symptoms and signs of dry eye, and recurrent episodes of ocular irritation related to pinguecula, which were refractory to prior medical treatments, successfully treated with argon laser photocoagulation.

Methods

A 36-year-old man presented with an elevated yellowish mass on his conjunctiva in his left eye, which was associated with dry eye symptoms and general discomfort, such as “tightening sensation” and “stiffness”. On clinical assessment, the left eye revealed a mild conjunctival injection, a fluorescein break-up time (FBUT) of 3.5 s, an abnormal fluorescein staining, and a Schirmer I test of 5 mm. Optical coherence tomography (OCT) imaging evidenced a height at the most elevated point of the pinguecula of 740 µm. The patient underwent argon-laser photocoagulation.

Results

After 2 weeks postoperatively, no residual of pinguecula or focal injection of the conjunctiva was detected by slit-lamp biomicroscopy and there was a significant improvement of clinical symptoms and signs: Schirmer I test and FBUT increased to 12 mm and >10 s, respectively, and fluorescein staining was absent. OCT imaging revealed a smooth structure of conjunctival contour, with a height of 404 µm. According to an ex juvantibus line of reasoning, definitive diagnosis was pinguecula-related dry eye disease.

Conclusion

Based on the concept that tear film instability and inflammation are two key components of the pathogenesis of dry eye, we coined the term “pinguecula-related dry eye disease,” which can be successfully treated by a complete, accurate removal of the lesion with argon laser photocoagulation.

Vascular Regression After Pinguecula Excision and Conjunctival Autograft Using Fibrin Glue

OBJECTIVES

To determine the change in local vascularization after pinguecula excision and conjunctival autograft secured with fibrin glue at 12 months.

METHODS

Thirty-one eyes of 31 patients which underwent excision and conjunctival autografting with fibrin glue were retrospectively reviewed. Anterior segment photography was obtained before and after the surgery. Cosmetic outcome was evaluated by patient self-grading (five-point scale; excellent (5), good (4), acceptable (3), poor (2), and very poor (1)), and medical evaluation of treatment outcome was based on subjective evaluation of vascularization on anterior segment photography (four-point severity scale; 0 [low] to 3 [high]). Clinical outcome and complications are reported at 12 months.

RESULTS

Overall cosmetic results were excellent or good in 93.5% (29 of 31) (score 4.68±0.60). Anterior segment photography showed that most cases demonstrated complete removal of pinguecula and regression of surrounding vascularization with mean change in score from 2.13±0.34 preoperatively to 0.09±0.30 postoperatively.

CONCLUSIONS

Pinguecula excision and conjunctival autograft using fibrin glue is an effective and safe method to remove pinguecula for cosmetic purposes. The method presented facilitated regression of vascularization.

Immunohistochemical localization of D-β-aspartic acid-containing proteins in pterygium

Biologically uncommon D-β-aspartic acid (D-β-Asp) residues have been reported to accumulate in organs affected by age-related disorders. In the present study, we investigated the localization of D-β-Asp-containing proteins in cases of pterygium, one of the most prominent age-related ocular conditions. Immunohistochemical localization of D-β-Asp-containing proteins was investigated in surgical specimens of pterygium from 20 patients and control specimens from 10 patients. Strong immunoreactivity to D-β-Asp-containing proteins was observed in subepithelial elastotic lesions and surrounding collagenous lesions from all surgical specimens with pterygia. In contrast, no immunoreactivity to D-β-Asp-containing proteins was seen in pterygium-free specimens. D-β-Asp-containing proteins are produced in organs as they are affected by the aging process. In addition, conversion of L- to D-aspartyl residues is accelerated by ultraviolet (UV) irradiation. Since pterygia can form due to aging or UV exposure, it is reasonable to find D-β-Asp-containing proteins in specimens with pterygia. Furthermore, since D-β-Asp is a non-native amino acid, D-β-Asp-containing proteins may be recognized as allogeneic antigens. Therefore, D-β-Asp-containing proteins in pterygia may responsible for the fibrovascular changes seen in the disorder.

One-year outcome of argon laser photocoagulation of pinguecula

PURPOSE

To determine the efficacy and safety of argon laser photocoagulation of pinguecula by evaluating 1-year outcomes.

METHODS

Twenty-one eyes of 15 patients treated with argon laser photocoagulation (photocoagulation group) and 23 eyes of 16 patients treated with surgical excision (excision group) were retrospectively reviewed. Cosmetic outcome was evaluated by patient's self-report on a 5-grade scale (excellent, good, acceptable, poor, and very poor), and evaluation of treatment outcome was based on objective findings of anterior segment photography and anterior segment optical coherence tomography.

RESULTS

Overall cosmetic results were excellent or good in 90.5% of laser-treated cases and 78.6% of surgically treated cases. There was no significant difference in cosmetic outcome (P = 0.15). Nineteen (90.5%) and 17 (63.9%) cases demonstrated complete removal of pingueculae after laser photocoagulation and surgical excision, respectively. The anatomic outcome was not significantly different between the 2 groups (P = 0.25). Subconjunctival hemorrhage and conjunctival scarring with an irregular surface occurred less frequently in the photocoagulation group than in the excision group [34.8% vs. 0% (P = 0.003) and 30.4% vs. 4.8% (P = 0.048), respectively].

CONCLUSIONS

Argon laser photocoagulation is an effective and safe method for removing a pinguecula for cosmetic purposes. The method facilitates control of the extent and depth of removal and thus minimizes conjunctival defects and other complications.

Advanced glycation end product deposits in climatic droplet keratopathy

BACKGROUND

Climatic droplet keratopathy (CDK), known as spheroid degeneration of the cornea, is one of the most frequent degenerative corneal disorders affecting visual function. However, the histochemical nature of the deposits seen in CDK is still unclear.

AIM

To investigate the pathogenesis of CDK, we investigated the immunohistochemical localisation of advanced glycation end products (AGEs) in surgical specimens of CDK.

METHODS

Immunohistochemical localisation of N(epsilon)-(carboxymethyl)-l-lysine (CML), N(epsilon)-(carboxyethyl)-l-lysine (CEL), pyrraline, pentosidine and imidazolone was examined in three corneas with CDK, six corneas with bullous keratopathy and three corneas without any corneal diseases.

RESULTS

In all the specimens with CDK, immunoreactivity was strong in CML, moderate in pyrraline and pentosidine, and weak in imidazolone. Immunoreactivity was absent in CEL. In contrast, no immunoreactivity to CML, pyrraline, pentosidine, imidazolone or CEL was detected in corneas with bullous keratopathy, or in corneas without any corneal diseases.

CONCLUSIONS

CDK is caused by an aggregation of AGE-modified proteins. The result is consistent with etiological findings that ultraviolet irradiation and ageing, both of which are accelerators of AGE formation, are closely related to the development of CDK.