Histopathology, matrix metalloproteinase-2 and alpha smooth muscle actin expression in Tenon's capsule of eyes with congenital glaucoma

Purpose To evaluate the ultrastructural features of collagen fibrils, matrix metalloproteinase (MMP) and alpha-smooth muscle actin (α-SMA) expression in the Tenon's capsule of buphthalmic eyes. Methods A prospective comparative case series study was conducted on 35 buphthalmic eyes vs 25 control eyes. Children with congenital glaucoma (CG) who underwent a combined trabeculectomy-trabeculotomy procedure with mitomycin C (CTTM); the Tenon's capsule was obtained during the surgical procedure. The control group included children with strabismus, the Tenon's capsule was obtained in the course of strabismus surgery. Both H&E and Masson's trichrome staining were done. The Metalloprotenease-2 (MMP-2), alpha smooth muscle actin (α-SMA) immunohistochemical staining was performed. Results Mean collagen percentage area by Masson trichrome stain in Tenons capsule was significantly higher in buphthalmic eyes (54.76% ± 0.32 vs 33.71% ± 1.4; P < 0.001). The percentage area of αSMA expression in Tenons capsule was significantly higher in buphthalmic eyes (4.93% ± 0.7 vs 2.00% ± 0.5; P < 0.001). However, MMP2 expression in Tenons capsule of the buphthalmic group was significantly lower than that of the control group (12.88% ± 2.95 vs 27.91% ± 0.2 respectively) P = 0.02. Conclusions Tenon capsule of buphthalmic eyes have their own histopathological features and properties making them more liable for fibrosis with high rate of failure following antiglaucoma surgeries. Such detailed information has not been published before which may aid in the identification of new antifibrotic therapies in management of glaucoma.

Limbal conjunctival approaches to extraocular muscles in the surgical treatment of previously operated strabismus

Purpose. Тo analyze clinical efficacy of the surgical treatment of previously operated strabismus using limbal incisions which are lengthening the conjunctiva and Tenon's capsule. Material and methods. The study included 440 patients (440 eyes) with previously operated strabismus at the age of 4 to 68 years old. The main group included 240 patients (240 eyes) who underwent strabismus surgery by limbal approach; the control group included 200 patients (200 eyes) who underwent surgery by paralimbal conjunctival approach. Horizontal strabismus occurred in 146 patients (60,8%) in the main group and in 158 (79%) in the control group. Horizontal strabismus in combination with vertical strabismus was found in 94 patients (39.2%) in the main group and in 42 patients (21%) in the control group respectively. The following approaches were applied: Y-shaped limbal approach, T-shaped incision of the conjunctiva, lower limbal peritomy, circular limbal approach with an additional horizontal incision towards the muscle being strengthened. Results. Good cosmetic result in the main group was achieved in 94.7% of cases, in the control group in 87% of cases, р<0.001. Re-surgery in the long term period was required for 39 patients (19.5%) in the control group and 14 patients (7%) in the main group, р<0.001. Conclusion. Limbal approaches performed to lengthening the conjunctiva and Tenon's capsule on the side of the weakened muscle and shortening on the side of the muscle being strengthened, are enhancing the effect of recession and resection, thereby contributing to the achievement of the state of orthotropy in 83% and have a good cosmetic result in 94.67% of cases. Key words: limbal conjunctival approaches, limbal conjunctival incisions, strabismus, children.

Comparative Study of a Modified Sub-Tenon’s Capsule Injection of Triamcinolone Acetonide and the Intravenous Infusion of Umbilical Cord Mesenchymal Stem Cells in Retinitis Pigmentosa Combined With Macular Edema

Retinitis pigmentosa (RP) is a hereditary retinal degenerative disease leading to eventual blindness. When RP is combined with macular edema (ME), the visual impairment further worsens. We compared a modified sub-Tenon’s capsule injection of triamcinolone acetonide (TA) and the intravenous infusion of umbilical cord mesenchymal stem cells (UCMSCs) in the treatment of RP combined with ME (RP-ME) to assess their safety and efficacy in eliminating ME and restoring visual function. A phase I/II clinical trial enrolled 20 patients was conducted. All patients were followed up for 6 months. There were no severe adverse effects in both groups. In retinal morphological tests, the central macular thickness (CMT) in TA group significantly decreased at first week, first and second month after injection (p &lt; 0.05). The CMT in UCMSCs group significantly decreased at first month after infusion. The rate of reduction of CMT in TA group was significantly greater than that in UCMSCs group at second month (p &lt; 0.05). Reversely, the rate of reduction of CMT in UCMSCs group was significantly greater than that in TA group at sixth month (p &lt; 0.05). In visual functional test, although there were no significant differences in visual acuity or visual fields within each group or between groups, but the amplitude of P2 wave of flash visual evoked potential (FVEP) showed significant increasing in TA group at second month in UCMSCs group at sixth month (p &lt; 0.05). At 6th month, the rate of growth in the amplitude of P2 wave in USMCSs group was significantly greater than that in TA group (p &lt; 0.05). This study suggests both modified sub-Tenon’s capsule injection of TA and intravenous infusion of UCMSCs are safe for RP-ME patients. TA injection is more effective at alleviating ME while improving visual function in a short term. UCMSC intravenous infusion shows slow but persistent action in alleviating ME, and can improve the visual function for a longer time. These approaches can be applied separately or jointly depending on the disease condition for patients to benefit maximumly.Clinical Trial Registration:http://www.chictr.org.cn, identifier ChiCTR-ONC-16008839

Benzalkonium chloride-induced myofibroblastic transdifferentiation of Tenon’s capsule fibroblasts is inhibited by coculture with corneal epithelial cells or by interleukin-10

Benzalkonium chloride (BAC) is used as a preservative in eyedrops but induces subconjunctival fibrosis that can result in failure of glaucoma surgery. Tenon’s capsule fibroblasts in subconjunctival tissue interact with the corneal epithelium through tear fluid. With the use of a coculture system, we have now investigated the effect of human corneal epithelial (HCE) cells on myofibroblastic transdifferentiation of human Tenon fibroblasts (HTFs) induced by BAC (5 × 10−6%). Immunofluorescence and immunoblot analyses revealed that the BAC-induced expression of α smooth muscle actin (αSMA) in HTFs was suppressed by coculture of these cells with HCE cells (p < 0.01). The concentration of interleukin-10 (IL-10) in culture supernatants of BAC-treated HTFs was increased by coculture with HCE cells (17.26-fold, vs. coculure, p < 0.001). Immunofluorescence and immunoblot analyses also showed that exogenous IL-10 (300 pg/ml) suppressed the BAC-induced expression of αSMA by 43.65% (p < 0.05) as well as the nuclear translocation of myocardin-related transcription factor-A (MRTF-A) by 39.32% (p < 0.01) in HTFs cultured alone. Our findings suggest that corneal epithelial cells may protect against subconjunctival fibrosis by maintaining IL-10 levels and preventing the MRTF-A-dependent transdifferentiation of HTFs into myofibroblasts.

Acute Bacterial Tenonitis and Conjunctivitis following Intravitreal Injection

A 73-year-old man presented 3 days after intravitreal injection (IVI) with bevacizumab for treatment of neovascular age-related macular degeneration with pain and redness around the injection site. Examination showed conjunctival edema and injection around the injection site and a central infiltrate at the injection site consistent with infection of Tenon’s capsule and the conjunctiva. Infection of a vitreous wick was considered, but vitreous inflammation was not present. Acute bacterial tenonitis and conjunctivitis were diagnosed, and the patient was prescribed topical antibiotic drops. The patient’s symptoms were resolved within 48 h following the use of topical antibiotic drops, so a culture was not performed. The patient did not develop endophthalmitis. To our knowledge, this is the first reported case of acute bacterial tenonitis and conjunctivitis of the injection site following IVI. Even with the use of betadine, infection of Tenon’s capsule and the conjunctiva may occur after IVI and must be differentiated from other causes of postinjection ocular redness such as chemical irritation of the ocular surface, corneal abrasions, and endophthalmitis.

TGFβ1, MMPs and cytokines profiles in ocular surface: Possible tear biomarkers for pseudoexfoliation

Purpose Pseudoexfoliation (PXF) is a unique form of glaucoma characterized by accumulation of exfoliative material in the eyes. Changes in tear profile in disease stages may give us insights into molecular mechanisms involved in causing glaucoma in the eye. Methods All patients were categorized into three main categories; pseudoexfoliation (PXF), pseudoexfoliation glaucoma (PXG) and cataract, which served as control. Cytokines, transforming growth factor β1 (TGFβ1), matrix metalloproteases (MMPs) and fibronectin (FN1) were assessed with multiplex bead assay, enzyme-linked immunosorbent assay (ELISA), gelatin zymography, and immunohistochemistry (IHC) respectively in different ocular tissues such as tears, tenon’s capsule, aqueous humor (AH) and serum samples of patients with PXF stages. Results We found that TGFβ1, MMP-9 and FN1 protein expression were upregulated in tears, tenon’s capsule and AH samples in PXG compared to PXF, though the MMP-9 protein activity was downregulated in PXG compared with control or PXF. We have also found that in PXG tears sample the fold change of TGF-α (Transforming Growth Factor-α), MDC (Macrophage Derived Chemokine), IL-8 (Interleukin-8), VEGF (Vascular Endothelial Growth Factor) were significantly downregulated and the levels of GM-CSF (Granulocyte Macrophage Colony Stimulating Factor), IP-10 (Interferon- γ produced protein-10) were significant upregulated. While in AH; IL-6 (Interleukin-6), IL-8, VEGF, IFN-a2 (Interferon- α2), GRO (Growth regulated alpha protein) levels were found lower and IL1a (Interleukin-1α) level was higher in PXG compared to PXF. And in serum; IFN-a2, Eotaxin, GM-CSF, Fractalkine, IL-10 (Interleukin-10), IL1Ra (Interleukin-1 receptor antagonist), IL-7 (Interleukin-7), IL-8, MIP1β (Macrophage Inflammatory Protein-1β), MCP-1 (Monocyte Chemoattractant Protein-1) levels were significantly upregulated and PDGF-AA (Platelet Derived Growth Factor-AA) level was downregulated in the patients with PXG compared to PXF. Conclusions Altered expression of these molecules in tears may therefore be used as a signal for onset of glaucoma or for identifying eyes at risk of developing glaucoma in PXF.

Preservation of the Tenon’s capsule and Sub-Tenon’s space after the autologous limbal-conjunctival transplantation in pterygium surgery

Background No previous studies have evaluated the scarring of the conjunctiva and Tenon’s capsule (TC) separately when only the conjunctiva is removed, and TC is preserved in the upper part of the bulb: the site designated for trabeculectomy. Thus, this cohort interventional study aims to investigate the scarring of the donor area after autologous limbal-conjunctival transplantation (ALCT) using anterior segment optical coherence tomography (AS-OCT). Methods Twenty-three eyes with pterygium were submitted to resection and local reconstruction with ALCT. AS-OCT images obtained from each eye preoperatively served as postoperative control. ALCT was removed superiorly with preservation of TC. The cure of this donor area occurred by secondary intention. AS-OCT was performed preoperatively and 30 and 180 days postoperatively in the donor area, measuring the thickness of the conjunctiva (epithelium and stroma) and TC. The sub-Tenon’s space (STS) was clinically assessed. Results The mean thickness of the conjunctival epithelium was 48.04 ± 11.37µm in the preoperative period and 51.87±15.04µm 180 days after surgery, without statistically significant difference (P=0.282). A statistically significant increase (P=0.005) in the mean thickness of the conjunctival stroma, from 85.35±23.10µm in the preoperative period to 101.61±20.19µm 180 days after surgery was found. TC had no significant changes, slightly increasing from 117.13±24.26µm preoperatively to 118.09±19.24µm (P=0.808) 180 days after surgery. STS was found in 19 (82%) eyes 180 days after surgery. Conclusions Following ALCT with TC preservation, scarring took place in the conjunctiva, epithelium, and stroma. The TC and the STS were preserved not showing any significant changes.