Comparative evaluation of four Descemet membrane endothelial keratoplasty graft preparation techniques

OBJECTIVE

To compare subjective and objective outcomes of 4 different Descemet membrane endothelial keratoplasty (DMEK) peeling techniques performed by novice surgeons at different stages in their surgical career.

DESIGN

An ex vivo prospective study.

METHODS

In the first round, 2 DMEK peeling techniques were pitched against each other: the peripheral scoring and Sinskey dissection technique with the peripheral scoring and microhoe dissection and the peripheral blunt microhoe dissection against the scleral spurectomy and microhoe dissection. Three surgeons with different operative experience performed the peeling. Outcome measures included graft peeling time, surgeon's peeling difficulty grading (on a scale of 1-10, 1 being the easiest and 10 the hardest), number of radial and circumferential tears before and after trephination, and tissue loss. The 2 techniques that performed the best from the first round proceeded to the final round to identify the best overall technique.

RESULTS

In total, 90 tissues (45 pairs) were peeled by 3 surgeons. Following the first-round results, the peripheral scoring and Sinskey dissection and peripheral blunt microhoe dissection proceeded to the final round. There were no significant differences between the groups in terms of peeling times, subjective feeling of difficulty, post-trephination tears, and peeling success rates (P > 0.05 for all). However, the peripheral scoring and Sinskey dissection technique had significantly fewer pretrephination radial tears (1.3 ± 1.3 vs 6.1 ± 5.2, P = 0.007) and circumferential tears (0.6 ± 0.9 vs 1.8 ± 2.1, P = 0.02).

CONCLUSIONS

This study demonstrates that the learning curve can be overcome quickly with appropriate DMEK peeling techniques. The peripheral scoring and Sinskey dissection peeling technique allows efficient peeling with fewer related tears.

Catastrophic vision loss from radiation-induced optic neuropathy

A 68-year-old woman presented with profound vision loss of 2-month duration in the right eye and 1-week duration in her left eye. This occurred in the context of craniopharyngioma that was twice resected and irradiated (54 Gy in 30 fractions) 9 months before her presentation. Ophthalmological examination revealed hand motion vision in the right eye and light perception vision in the left eye with poorly reactive pupils and bilateral optic disc pallor. A non-contrast MRI of the brain and sella showed significant reduction of the sellar mass. A repeat MRI of the brain and orbits with gadolinium showed pre-chiasmatic enhancement of both optic nerves. The diagnosis of radiation-induced optic neuropathy was made. Despite treatment with high-dose intravenous corticosteroids, 19 sessions of hyperbaric oxygen therapy, and 3 doses of intravenous bevacizumab, her vision worsened to no light perception in both eyes.

Effects of ranibizumab and amfenac on the functional abilities and radiosensitivity of uveal melanoma cells

PURPOSE

To evaluate the effects of ranibizumab and amfenac in human uveal melanoma cell lines and to explore the ability of these compounds to sensitize uveal melanoma cells to radiation therapy.

METHODS

The 92.1 human uveal melanoma cell line was cultured and subjected to the proposed treatment (ranibizumab, amfenac, and a combination of both). Proliferation, migration, and invasion assays of the 92.1 uveal melanoma cell line were assessed after pretreatment with ranibizumab (125 mg/mL), amfenac (150 nM), or a combination of both. In addition, proliferation rates were assessed after treatment with ranibizumab and amfenac, and the cells were subsequently exposed to various radiation doses (0, 4, and 8 Gy).

RESULTS

Proliferation assay: cells treated with a combination of ranibizumab and amfenac had lower proliferation rates than controls (p=0.016) and than those treated with only ranibizumab (p=0.033). Migration assay: a significantly lower migration rate was observed in cells treated with amfenac than the control (p=0.014) and than those treated with ranibizumab (p=0.044). Invasion assay: there were no significant differences among the studied groups. Irradiation exposure: in the 4 Gy dose group, there were no significant differences among any groups. In the 8 Gy dose group, treatment with ranibizumab, amfenac, and their combination prior to application of the 8 Gy radiation led to a marked reduction in proliferation rates (p=0.009, p=0.01, and p=0.034, respectively) compared with controls.

CONCLUSION

Combination of ranibizumab and amfenac reduced the proliferation rate of uveal melanoma cells; however, only amfenac monotherapy significantly decreased cell migration. The radiosensitivity of the 92.1 uveal melanoma cell line increased following the administration of ranibizumab, amfenac, and their combination. Further investigation is warranted to determine if this is a viable pretreatment strategy to render large tumors amenable to radiotherapy.

Blue-light filtering alters angiogenic signaling in human retinal pigmented epithelial cells culture model

Background

Light exposure and more specifically the spectrum of blue light contribute to the oxidative stress in Age-related macular degeneration (AMD). The purpose of the study was to establish whether blue light filtering could modify proangiogenic signaling produced by retinal pigmented epithelial (RPE) cells under different conditions simulating risk factors for AMD.

Methods

Three experiments were carried out in order to expose ARPE-19 cells to white light for 48 h with and without blue light-blocking filters (BLF) in different conditions. In each experiment one group was exposed to light with no BLF protection, a second group was exposed to light with BLF protection, and a control group was not exposed to light. The ARPE-19 cells used in each experiment prior to light exposure were cultured for 24 h as follows: Experiment 1) Normoxia, Experiment 2) Hypoxia, and Experiment 3) Lutein supplemented media in normoxia. The media of all groups was harvested after light exposure for sandwich ELISA-based assays to quantify 10 pro-angiogenic cytokines.

Results

A significant decrease in angiogenin secretion levels and a significant increase in bFGF were observed following light exposure, compared to dark conditions, in both normoxia and hypoxia conditions. With the addition of a blue light-blocking filter in normoxia, a significant increase in angiogenin levels was observed. Although statistical significance was not achieved, blue light filters reduce light-induced secretion of bFGF and VEGF to near normal levels. This trend is also observed when ARPE-19 cells are grown under hypoxic conditions and when pre-treated with lutein prior to exposure to experimental conditions.

Conclusions

Following light exposure, there is a decrease in angiogenin secretion by ARPE-19 cells, which was abrogated with a blue light - blocking filter. Our findings support the position that blue light filtering affects the secretion of angiogenic factors by retinal pigmented epithelial cells under normoxic, hypoxic, and lutein-pretreated conditions in a similar manner.

Analysis of HSP90 Expression Is Valuable in the Differential Diagnosis of Ocular Surface Squamous Lesions

OBJECTIVES

The aim of this study was to evaluate heat shock protein 90 (HSP90) expression in squamous lesions (SLs) and to assess its diagnostic value for different lesions within the SL spectrum.

METHODS

A total of 70 conjunctival SLs, including 19 papillomas, 22 cases of conjunctival intraepithelial neoplasia (ConINs) I, 11 cases of ConIN II, six cases of ConIN III, and 12 squamous carcinomas (sqCAs), were evaluated using the German immunoreactive score against HSP90.

RESULTS

Cytoplasmic HSP90 expression differed between low- and high-grade lesions (P < .001). Among high-grade lesions, the nuclear HSP90 score was higher in the ConIN III-sqCA group than in the ConIN II group (P = .0162). A percentage of total thickness staining of less than 73% differentiated between ConIN III and sqCA.

CONCLUSIONS

The expression of HSP90 is particularly useful to differentiate low-grade from high-grade lesions of the conjunctiva. HSP90 may play an important role in the malignant transformation of SLs and could be a new target for therapy.

SIRT2 Expression Is Higher in Uveal Melanoma than In Ocular Melanocytes

PURPOSE

Sirtuins (SIRTs) are the family of proteins associated with the cell cycle and that correlate with cancer development and progression. SIRTs have never been studied in uveal melanocytes. The aim of this study is to characterize the expression of SIRT2 in uveal melanoma (UM) cases and compare it with the expression of SIRT2 in melanocytes of the uveal tract of normal human eyes (NHE).

METHODS

Twenty-one formalin-fixed, paraffin-embedded human UM cases were immunostained for SIRT2, along with 15 NHE obtained from the Eye Bank of Canada.

RESULTS

SIRT2 expression was higher in melanomas than in normal melanocytes of both tumor and donor eyes (p < 0.0001). No significant difference in SIRT2 expression was found when comparing normal melanocytes in UM and NHE cases.

CONCLUSIONS

SIRT2 expression is significantly stronger in UM cells than in normal ocular melanocytes. This finding may indicate an important role of SIRT2 as a prognostic marker in UM progression. SIRT2 should also be investigated as a possible therapeutic target.

Diagnostic value of SOX-10 immunohistochemical staining for the detection of uveal melanoma

Objectives

SOX-10 has been shown to be a sensitive marker of cutaneous melanoma. This study aimed to evaluate Sox-10 expression in uveal melanoma.

Methods

A total of 40 tissue blocks of enucleated eyes with uveal melanoma were cut and stained using an anti-SOX-10 mouse monoclonal antibody and HMB-45 antibody.

Results

SOX-10 showed exclusive nuclear positivity in 100% of the uveal melanoma cases (38/38). HMB-45 showed cytoplasmic positivity in 97.3 (37/38). Positivity for SOX-10 was also noted in the inner and outer nuclear layers of the retina in 78% of the enucleated eyes.

Conclusions

SOX-10 expression proved to be the most sensitive marker for uveal melanoma, and therefore, we propose a modified panel for the diagnosis of uveal melanoma that includes both SOX-10 and HMB-45. The observation of distinct, diffuse nuclear SOX-10 expression in retinal inner and outer nuclear layers is a finding that warrants further investigation as a marker for retinoblastoma.