Arantxa Acera

Inflammatory Markers in the Tears of Patients with Ocular Surface Disease

Purpose: To determine the concentration of interleukins (IL-1β and -6) and matrix metalloproteinase 9 (pro-MMP-9) in the tears of patients with different ocular surface diseases and to examine the possible relationship between the disorders and molecular inflammation. Methods: 77 patients diagnosed as having different ocular surface disorders and 18 normal control subjects were studied. Patients were routinely examined and separated into 5 groups: (1) control, (2) blepharitis, (3) ocular allergic disease, (4) dry eye and (5) conjunctivochalasis. Ten microliters of tears were collected by a Weck cell sponge. The concentrations of IL-1β, IL-6 and pro-MMP-9 were measured by enzyme-linked immunosorbent assay, and the MMP-9 activity was evaluated with gelatin zymography. Results: Levels of IL-1β and IL-6 in tear fluid were significantly higher in conjunctivochalasis (p = 0.0062 and p = 0.0134) than in the control group. Pro-MMP-9 levels were significantly elevated in blepharitis (p = 0.013), in allergic eye disease, in dry eye and in conjunctivochalasis (all p < 0.001), in comparison to controls. Conclusions: Pro-MMP-9 levels in tears are elevated in all of the studied pathologies especially in ocular allergy and conjunctivochalasis. However, IL-1β and IL-6 were only found to be overexpressed in conjunctivochalasis. These findings illustrate the selective implication of different molecules in each disorder.

Inflammatory response to contact lenses in patients with keratoconus compared with myopic subjects.

Purpose: To determine the levels of inflammatory molecules in the tears of patients who wore rigid gas permeable (RGP) contact lenses (CLs) and who had either keratoconus or myopia. Methods: A prospective, case-control study with 4 groups enrolled 20 RGP CL keratoconus wearers and 28 keratoconus non-lens wearers, 20 myopic CL wearers, and 20 subjects with myopia that were non-lens wearers (1 eye per patient). Fifteen microliters of tears were collected by capillary flow. The concentration of cytokines (interleukin-6 [IL-6], IL-10, and tumor necrosis factor [TNF]-α), cell adhesion molecules (intercellular adhesion molecule 1 [ICAM-1] and vascular cell adhesion molecule 1 [VCAM-1]), and matrix metalloproteinase (MMP-9) was measured by enzyme-linked immunosorbent assay. Results: The most significant differences associated with the wearing of RGP CLs in patients with keratoconus were seen in increased levels of proinflammatory cytokines (IL-6, 23.7 vs. 6.4 pg/mL, P = 0.001; TNF-α, 21.3 vs. 3.8 pg/mL, P = 0.028) and cell adhesion molecules (ICAM-1, 32.8 vs. 7.7 ng/mL, P < 0.0001; VCAM-1, 57.4 vs. 29.3 ng/mL, P < 0.0001). In patients with myopia, increased levels of TNF-α (4.2 vs. 1.8 pg/mL, P < 0.0001) and MMP-9 (12.9 vs. 6.1 ng/mL, P < 0.0001) were associated with the wearing of RGP CLs. Conclusions: Wearing RGP CLs induces overexpression of IL-6, TNF-α, ICAM-1, and VCAM-1 in the tears of patients with keratoconus. These increased levels are higher in cases with severe keratoconus.

Tear proteome and protein network analyses reveal a novel pentamarker panel for tear film characterization in dry eye and meibomian gland dysfunction.

Dry eye and meibomian gland dysfunction are common ocular surface disorders. Discrimination of both conditions often may be difficult given the overlapping of signs and symptoms, and the lack of correlation with clinical parameters. A total of 144 individuals were included in this study. To search for proteome differences, tear proteins were collected by Merocel sponge and analyzed using 2D-PAGE. Comparative tear protein profile analysis indicated changes in the expression levels of fifteen proteins. Subsequent to MALDI-TOF/TOF protein identification, network analysis revealed expression/interaction connections with other proteins, thereby identifying additional putative markers. A screening validation assay demonstrated the discriminative power of six candidate biomarkers. A further validation study using multiplexed-like ELISA assays in tear samples collected with both sponge and capillary confirmed the high discriminatory power of five biomarkers: S100A6, annexin A1 (ANXA1), annexin A11 (ANXA11), cystatin-S (CST4), and phospholipase A2-activating protein (PLAA) with an area under ROC curve (AUC)≥ 97.9% (sensitivity ≥ 94.3%; specificity ≥ 97.6%) when comparing dry eye and control individuals. This panel also discriminated between dry eye, meibomian gland dysfunction and control individuals, with a global correct assignment (CA) of 73.2% between all groups. Correct assignment was not found to be significantly dependent on the tear collection method.

Changes in tear protein profile in patients with conjunctivochalasis.

Purpose: To compare the protein profiles of tears from normal volunteers and patients with conjunctivochalasis (CCH), with a view to identifying proteins whose expression is altered in this pathology. Methods: Tears from 8 normal subjects and 6 patients with CCH were analyzed by 2-dimensional electrophoresis. Total protein from tears was separated in the first dimension by isoelectric focusing, and the second dimension was carried out using 8%-16% sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The gel images were analyzed using Progenesis SameSpot software. Those spots of interest were manually cut out from the gels, and the corresponding proteins were identified by matrix assisted laser desorption/ionization-time of flight (MALDI-TOF). Expression levels of proteins that had been found to be significantly altered were further verified by Western blot. Results: Approximately 250 spot proteins were detected in the whole tear proteome. Twenty-four spots were significantly upregulated in CCH compared with that in controls. Eleven protein spots were identified, which included proteins belonging to the S100 family (A8, A9, A4; 2.44, 1.71, and 2.82 fold upregulation, respectively), guanosine triphosphate-binding protein 2 (1.95 fold), l-lactate dehydrogenase A-like 6B (2.32 fold), fatty acid-binding protein (2.01 fold), keratin type I cytoskeletal 10 (1.81 fold), glutathione S-transferase P (2.27 fold), peroxiredoxin-1, peroxiredoxin-5 (1.79- and 1.92 fold, respectively), and cullin-4B+ glyceraldehyde 3-phosphate dehydrogenase (1.96 fold). Conclusions: We have identified a group of proteins, which is upregulated in CCH tears. Although some of them, such as S100A4, S100A8, and peroxiredoxin-5, are markers of inflammation and oxidative processes, monitoring their levels in CCH might be useful for assessing the severity and progression of the disease.

Human Basal Tear Peptidome Characterization by CID, HCD, and ETD Followed by in Silico and in Vitro Analyses for Antimicrobial Peptide Identification.

Endogenous peptides are valuable targets in the analysis of biological processes. The tear film contains proteins and peptides released by the tear duct mucosal cells, including antimicrobial peptides involved in the protection against exogenous pathogens; however, the peptide content of the tear liquid remains poorly characterized. We analyzed naturally occurring peptides isolated from human basal tears. Mass spectrometry analysis of endogenous peptides presents a number of drawbacks, including size heterogeneity and nonpredictable fragmentation patterns, among others. Therefore, CID, ETD, and HCD methods were used for the characterization of the tear peptide content. The contribution of DMSO as an additive of the chromatographic solvents was also evaluated. We identified 157, 131, and 122 peptides using CID-, ETD-, and HCD-based methods, respectively. Altogether, 234 different peptides were identified, leading to the generation of the biggest data set of endogenous tear peptides to date. The antimicrobial activity prediction analysis performed in silico revealed different putative antimicrobial peptides. Two of the extracellular glycoprotein lacritin peptides were de novo synthesized, and their antimicrobial activity was confirmed in vitro. Our findings demonstrate the benefits of using different fragmentation methods for the analysis of endogenous peptides and provide a useful approach for the discovery of peptides with antimicrobial activity.

Tear MMP-9 levels as a marker of ocular surface inflammation in conjunctivochalasis.

PURPOSE To evaluate the efficacy of surgical treatment for conjunctivochalasis by monitoring matrix metalloproteinase (MMP)-9 levels in the tears of patients with conjunctivochalasis before and after surgery and their correlation with clinical signs and symptoms. METHODS Twelve eyes of patients with symptomatic conjunctivochalasis were included in this study as well as five eyes of healthy volunteers. Ocular surface inflammation was measured in terms of the concentration of pro-MMP-9 in tears, by enzyme-linked immunosorbent assay and zymography. Tear analysis was performed before and 1 month after surgery. The surgical technique consisted of the excision of redundant tissue and the use of organic glue for wound closure. RESULTS The concentration of pro-MMP-9 was significantly higher in the conjunctivochalasis eyes than in the healthy controls (223.4 ± 74.53 ng/mL vs. 20.32 ± 5.21 ng/mL; P < 0.001). Tear pro-MMP-9 levels decreased significantly after conjunctival resection in patients with conjunctivochalasis without dry eye compared with patients with conjunctivochalasis and dry eye associated. Zymographic analysis indicated that MMP-9 is present in its active form only in conjunctivochalasis tears. After a follow-up of 4.9 ± 1.3 weeks, all operated eyes were found to have recovered a smooth and stable conjunctival surface, epithelial defects had improved, and epiphora had been resolved in 89% of cases. CONCLUSIONS Our results indicate that inflammation is likely to play a relevant role in the pathogenesis of conjunctivochalasis. Appropriate surgery decreases inflammatory activity, leading to symptom improvement, and tear analysis may facilitate the treatment of the ocular surface.

The PLGA implant as an antimitotic delivery system after experimental trabeculectomy.

PURPOSE To investigate the effect of poly (lactic-co-glycolic acid) (PLGA) implants loaded with mitomycin C (MMC) and with different adjuvant treatments after glaucoma filtration surgery (GFS), in comparison to standard treatments. METHODS Forty-two New Zealand White rabbits underwent bilateral GFS and received different treatments: topical MMC (group 1); topical 5-fluorouracil (5-FU; group 2); PLGA implant (group 3); MMC-loaded and -coated PLGA implant (group 4); MMC-loaded and 5-FU-coated PLGA implant (group 5); subconjunctival bevacizumab (group 6); MMC-loaded PLGA implant and subconjunctival bevacizumab (group 7); and no treatment (right eye of all animals; control group). Intraocular pressure (IOP) and filtering bleb were evaluated on different days after GFS. Histology was performed to examine the conjunctiva, sclerotomy, filtering bleb, and persistence of the implant. RESULTS The best hypotensive results were achieved in the MMC-loaded and -coated PLGA implant group, which presented the lowest IOP values on days 1, 5, 7, 14, and 28 after GFS. Excluding the implant groups, in which the bleb could not be properly measured, bleb survival was superior to controls in groups 1, 2 and lower in group 6. Group 7 presented greater extension, height, and vascularization of the bleb. Epithelial thinning and lymphoplasmacytic infiltrate were observed in groups 1, 2, 4, 5, and 7. The rates of closure of the sclerotomy and bleb were 100% and 76%, respectively, and implant persistence was 95%. CONCLUSIONS MMC-loaded and -coated implants have optimal surgical results, followed by topical MMC application. In this experimental model, bevacizumab could interact with MMC.

Novel Molecular Diagnostic System of Limbal Stem Cell Deficiency Based on MUC5AC Transcript Detection in Corneal Epithelium by PCR-Reverse Dot Blot

PURPOSE To evaluate the sensitivity and specificity of a PCR-strip system based on reverse dot blot for detection of MUC5AC mRNA in corneal epithelium samples from patients with limbal stem cell deficiency (LSCD), and to determine the correlation with clinical diagnosis. METHODS We obtained 87 corneal impression cytology (IC) samples from 55 subjects (37 patients clinically diagnosed with LSCD and 18 control subjects). Total RNA was extracted from each IC sample and retrotranscribed to cDNA. MUC5AC mRNA transcript was amplified by a customized RT-PCR assay and detected in PCR strips based on reverse dot blot hybridization and in agarose gels. Conjunctival IC samples were used as positive controls. RESULTS Forty-four of 45 corneal IC samples obtained from patients clinically diagnosed with LSCD were positive for MUC5AC, whereas 34 of 42 corneal ICs from healthy subjects were negative for MUC5AC. Four healthy corneas were found MUC5AC positive, and four rendered inconclusive results. A correlation of 91.4% (P < 0.001) between molecular testing and clinical diagnosis was found. The overall sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the PCR-strip system were 98%, 89%, 92%, and 97%, respectively. CONCLUSIONS Corneal epithelium MUC5AC transcript detection by reverse dot blot PCR-strip is a highly sensitive technique for LSCD diagnosis. The test results strongly correlate with clinical diagnosis of characterized LSCD cases. The PCR-strip system may be used for early detection, and for the detection of mild cases of LSCD, and constitutes an objective clinical tool for the monitoring of treatments and surgical decisions.

Human tear proteomics and peptidomics in ophthalmology: Toward the translation of proteomic biomarkers into clinical practice

Tears are a complex biological mixture containing electrolytes, metabolites, lipids, mucins, some small organic molecules, and proteins. The tear film has various roles in the lubrication, protection from the external environment, and nutrition of the cornea; it is also involved in the modulation of the optical properties of the eye. Tear composition reflects the physiological condition of the underlying tissues. Therefore, the tear fluid is useful in the evaluation of health and disease states and it is a valuable source of biomarkers for objective analysis of ocular and systemic diseases. The relatively high protein concentration of this fluid and the ease of noninvasive sample collection make it suitable for diagnostic and prognostic purposes. Efforts in proteomics research have positively affected to the field of ophthalmology, and the knowledge on the tear proteome has expanded considerably in the last few years. Nevertheless, despite a large amount of available data and the many biomarkers proposed for several eye and systemic diseases, the extent of translation to well-characterized and clinically useful tools has been largely insufficient. As for most of other biofluids, the road from discovery to clinical application is still long and full of pitfalls. In this review, we discuss the proteomic approaches used in the characterization of tear protein and peptide content, recapitulating the main studies and the progress done. We also present a brief summary of the path from discovery to clinical application of tear protein markers, with some representative examples of translation from the bench to the bedside. SIGNIFICANCE In this review we cover the most relevant proteomic approaches used in the characterization of the tear proteome, and for the first time we also focus in advances performed in the nowadays emerging peptide content characterization. In this context, we recapitulate on the main studies and the progresses done in this field. We also present a concise overview of the course that may be happen from discovery to clinical application for tear protein markers. Finally we include some representative examples of translation from the bench to the bedside.

Queratoplastia penetrante protegida: técnica quirúrgica y respuesta del endotelio

espanolObjetivo: Describir la tecnica y conocer la seguridad de una cirugia de queratoplastia penetrante protegida (QPP). Metodos: Se describe una tecnica de QPP. Se compara la evolucion postoperatoria del endotelio corneal de 17 ojos intervenidos con esta tecnica, comparandola con la de 24 ojos intervenidos con queratoplastia penetrante estandar (QP), en tres periodos de tiempo: 3-6 meses, 7-12 meses y mas de 12 meses. Para el analisis estadistico se realizo el test no parametrico de la U de Mann-Whitney. Resultados: En ninguno de los casos intervenidos con tecnica de QPP se aprecio extrusion de tejidos o estructuras intraoculares. El recuento endotelial no mostro diferencia estadisticas en el periodo de 3-6 meses (QP = 2.086 DE 566; QPP = 1.858 DE 671; p = 0,2702) y el de mas de 12 meses (QP = 1.574 DE 745; QPP = 1.419 DE 810; p = 0,2882). Existio diferencia significativa en el periodo de 7-12 meses (QP = 2.255 DE 831; QPP = 1.569 DE 623; p = 0,0397). Conclusiones: La QPP que se describe puede reducir el riesgo de ciertas complicaciones perquirurgicas. El endotelio no muestra un sufrimiento significativo cuando se compara con la tecnica de QP estandar. EnglishPurpose: To describe the technique and to evaluate the safety of protected penetrating keratoplasty (PPK). Methods: A technique for penetrating keratoplasty is described. The postoperative endothelial cell counts of 17 eyes in which this operative technique was used were compared with those in 24 eyes in whom the standard operative technique for penetrating keratoplasty (PK) was used. The post-operative time periods were grouped as follows: 3-6 months, 7-12 months and >12 months. For statistical analysis, the Mann-Whitney U non-parametric test was employed. Results: There was no case where tissue extrusion occurred during the procedure. The endothelial cell count was similar in both groups for the 3-6 month period (PK = 2,086, DS 566; PPK = 1,858, DS 671; p = 0.2702) and >12 months period (PK = 1,574, DS 745; PPK = 1,419, DS 810; p = 0.2882). There was a significant difference in the 7-12 month period (PK = 2,255, DS 831; PPK = 1,569, DS 623; p = 0.0397). Conclusions: The described technique of PPK may reduce the risk of per-operative complications. Damage to the endothelium is not increased compared with that seen following the standard PK procedure.