Clinical outcomes of autologous cultured oral mucosal epithelium transplantation for treatment of limbal stem cell deficiency

The review presents an analysis of clinical trials results for autologous cultured oral mucosal epithelium transplantation (COMET) in patients with bilateral corneal limbal stem cell deficiency (LSCD) over the past 15 years. Detailed characteristics and evaluation are given for anatomical outcomes, visual acuity changes, and complication rates. The results obtained during the analysis confirm the consistency of the concept of corneal re-epithelization by means of COMET. COMET promoted persistent corneal re-epithelization in 81.5% of cases, and visual acuity improvement in 78.8% of patients with LSCD. COMET does not require systemic immunosuppression, and it is accompanied by much smaller numbers and significantly lower grades of complications compared with keratoprosthesis. About 15% of patients experienced developing superficial peripheral corneal neovascularization regressed spontaneously by 12 months of observation. Based on the COMET clinical trials results, the management of patients with bilateral LSCD is under optimization by reference to the pathogenesis of the underlying disease. Thus, autologous cultured oral mucosal epithelium transplantation seems promising for further studies and introduction into routine clinical practice

Impact on visual acuity in neovascular age related macular degeneration (Namd) in europe due to covid-19 pandemic lockdown

This is a retrospective, multicenter study of consecutive patients with nAMD scheduled for a visit and/or a treatment with an intravitreal injection (IVI) during the 3 months before lockdown in the Ophthalmology Departments of six centers of Europe.The study was conducted on 546 patients, of which 55.13% were females, almost 100% of the patients were White/Caucasian race, and 71.53% of the patients presented a type 1 macular neovascularization (NVM). A total of 62.82% of patients (343 patients) that were on scheduled clinic visits and/or intravitreal injection treatment during the 3 months before the quarantine did not attend either to visit or for treatment during the lockdown. The mean number of injections during the lockdown was significantly reduced. This was followed by a significant reduction in the mean best-corrected visual acuity (BCVA) between the 3 months before the lockdown (mean BCVA of 60.68 ± 19.77 letters) and 6 months after lockdown (mean BCVA of 56.98 ± 22.59 letters). Patients with better BCVA before the lockdown and the ones showing neovascular activity were more likely to attend their scheduled visits and/or IVI treatments. The COVID-19 pandemic and the lockdown have led to a decrease in the number of IVI treatments in patients with nAMD, evidencing a significant vision loss at 6 months

LONG-TERM RESULTS OF DIFFERENT UV-CROSSLINKING TECHNIQUES IN PATIENTS WITH PROGRESSIVE KERATOCONUS

Purpose. To compare a clinical effectiveness of different UV-crosslinking techniques in patients with progressive keratoconus.Material and methods. Randomized prospective clinical trial included 130 eyes of 117 keratoconic patients. There were created 2 equal groups of 65 eyes. In the group I patients underwent a classical UV-crosslinking technique with a complete central corneal deepithelialization, in the group II a UV-crosslinking with dosed corneal epithelium scarification was performed using a new device. The postoperative follow-up period was 24 months. Preoperatively in the group I the uncorrected visual acuity (UCVA) was 0.21±0.11, the best corrected visual acuity (BCVA) was 0.49±0.14, the central corneal pachymetry (CCP) – 469.1±23/4μm, the mean keratometry (Kave) – 46.1±1.7D, in the group II: UCVA was 0.22±0.09, BCVA – 0.48±0.12, CCP – 475.2±28.5μm, Кave – 46.7±1.4D.Results. The mean postoperative pain score was 6.9±1.3, relief on the 3-rd ±1.2 day post-op. in the group I, and 2.8±1.1 relief on the 1-st±0.4 day post-op. in the group II. All patients had a 0.1 to 0.12 visual acuity loss 7 days after the surgery that was due to a mild corneal opacification. At 3 months after operation in both groups the UCVA and the BCVA were back to their preoperative values. In the group I the UCVA increased by 0.07±0.03 (р<0.05) 2 years after the treatment, the BCVA increased by 0.11±0.04 (р<0.05). At that time in the group II the similar values were obtained: 0.08±0.02 (р<0.05), 0.1±0.04 (р<0.05) respectively. The Kave index in both groups gradually decreased during first 12 months after operation and then stabilized. At the end of the follow up it was lower by 2.6±0.5D (р<0.05) in the group I and by 2.4±0.3D (р<0.05) in the group II. According to the anterior OCT, the depth of demarcation line was 327±11μm in the group I and 318±13μm in the group II. The demarcation line was absent in all cases 12 months after surgery. In the early postoperative period 3 months after operation the CCP gradually decreased. It reduced by 3.77±0.83% (р<0.05) in the group I and by 3.17±0.88% (р<0.05) in the group II. After that the CCP slowly increased during the entire follow-up, but 24 months later it was still lower by 2.36±0.57% (р<0.05) in the group I and by 1.68%±0.75 (р<0.05) in the group II. Confocal microscopy 1 month after surgery revealed typical changes of corneal structure at the depth up to 310±9μm (290 to 335) in the group I and 300±8μm (280 to 330) in the group II. A full reinnervation and the repopulation of the cornea with keratocytes was seen 6 months after operation. The only complication (delayed corneal epithelization) was in the group with classical UV-crosslinking technique.Conclusions. The trial revealed similar clinical outcomes after classical UV-crosslinking technique and UV-crosslinking with dosed corneal epithelium scarification, however in the latter case during the postoperative period the severity and duration of pain were significantly reduced

Survival of the posterior lamellar cornea graft keratocytes and endothelial cells cultivated in the modified corneal preservation media

Purpose. To study the survival of keratocytes and endothelial cells of a human donor cornea storage in the standard and the new media which was specifically designed for optim ized cornea hydration.Material and methods. 2D cell cultures of keratocytes and endothelial cells obtained from the Eye tissue bank were used for culture in improved storage media over a period of 14 and 7 days subsequently. To confirm phenotype characteristics, the cells were stained by the following markers: for keratocytes – Lumikan, Keratocan, and α-smooth muscle actin; for endothelial cells – ZO-1 and Na/K-ATPase. The onset of apoptosis in cell culture of keratocytes were detected with Cytochrome C, BAX, and Caspase 3 and 8. Viability of cell cultures after the cultivation was carried out using a commercial set of «Live and Dead». Morphology of the endothelial cells was assessed using an electron scanning microscope.Results. It was shown that the 2D keratocyte culture cultured in the improved storage media expressed specific markers: Lumican, Keratocan, and did not express α-smooth muscle actin. There were no markers of apoptosis in the cell culture of keratocytes after 14 days of cultivation. Corneal endothelium cultured in the improved storage media expresses  ZO-1, Na/K-ATPase and presented hexagonal cell shape morphology according to electron microscopy.Conclusion. The improved storage media allow to preserve the unique phenotype of keratocytes, with a slight decrease in proliferative cells activity during 14 days. The media maintain a viable and functional corneal endothelium for at least seven da ys of cultivation

COVID-19 outbreak and increased risk of amblyopia and epidemic myopia: Insights from EUROCOVCAT group

The most common cause of vision impairment in children is amblyopia. It is defined as impaired visual acuity in one or both eyes that is present with no demonstrable abnormality of the visual pathway and is not immediately resolved by wearing glasses. After the World Health Organization (WHO) recognized COVID-19 as a global pandemic on March 11, 2020, widespread changes and restrictions to social and sanitary practices have presented significant issues in access to eye care during the COVID-19 pandemic. A reduction of more than 80% in pediatric eye care volume up to its total cessation has been observed in different departments. In this scenario, reduced or absent eyesight, due to delay in timely treatment of amblyopic conditions, could create major, long-lasting effects on all aspects of life, including daily personal activities, interacting with the community, school and work opportunities and the ability to access public services. Processes coming out of lockdown should be gradually easing restrictions giving priority to ophthalmology and eye care facilities so that amblyopia does not remain unattended and irreversible as in adults due to lack of timely treatments. If not reversible, this process could lead to a dramatic increase in disability and unsustainable social costs for many governments

Towards the matter of genetic consulting in various forms of congenital and hereditary eye diseases

Purpose. To evaluate the results in genetic consulting of patients with various forms of congenital and hereditary eyes pathology.Material and methods. The study is based on an analysis of results in genetic consulting and molecular genetic investigations of DNA samples of 18 patients: congenital corneal dystrophy (n=3); congenital cataract (n=11); Norrie disease (n = 4). All patients had a comprehensive ophthalmologic clinical and functional examination according to the forms of pathology. Geneticist physician conducted a genealogical analysis. A study of exons and flanking intronic regions was performed using methods of analysis of amplified fragment length polymorphism, restriction fragments and direct sequencing.Results. The clinical diagnosis of endothelial corneal dystrophy with autosomal recessive mode of inheritance using molecular genetic methods in 2 of the 3 cases was confirmed, and a de novo mutation in the gene SLC4A11 non-described previously was found. In the group with hereditary diseases the lens pathogenic mutations were detected in the GJA3 andGJA8 genes in 2 of 11 cases (18%). Pathogenic mutations in NDP gene were detected only in 2 of 4 family members studied, and its sibling proband, directed to the genetic analysis of patients with a clinical diagnosis Norrie disease. In another of the studied probands the diseasecausing mutation was not reveled, and thus, the molecular genetic diagnosis of Norrie disease was not confirmed.Conclusion. For the first time in the Russian Federation pathogenic mutations in the gene SLC4A11 collagen, previously did not described in the literature, were revealed in patients with congenital endothelial corneal dystrophy, in a patient with congenital cataract in the gene GJA8. The success of genetic consulting depends on the complete genealogical analysis, and the correct determination of the clinical and genetic form of pathology

DEVELOPMENT OF BIOENGINEERING DESIGN OF ARTIFICIAL CORNEA BASED ON TISSUE MATRIX MADE OF SPIDROIN AND CULTIVATED CELLS OF EYE LIMBUS ZONE

Purpose. To study prerequisites for a development of artificial cornea bioengineered design based on recombinant spidroin tissue matrix by behavior evaluation of 2D (planar) and 3D cell (threedimensional) cultures on its surface.Material and methods. We studied epithelioid and stromal primary cell cultures (MSC-L) received from the limbal zone of post-mortem donor eyes. Cells were seeded on Petri dishes and on cavities of cultural trays (Corning, USA). To get spheroid structures the cells after the second passage underwent the centrifuge and were seeded on agarous trays then were cultivated in thermostatic chamber (Cell-IQ, Chip Man Technologies, Finland) under standard conditions (37° C, 5% CO2). Control over cell growth and morphology in trays was conducted under inverted microscope CKX41 (Olympus, Japan). To count the cell quantity and their viability the automatic cell counter Countess (Invitrogen, USA) was used, to analyze the surface proteins expression the flow cytofluorimetry was applied. For matrices colonization we used the 3rd passage MSC-L and 7-day spheroids of MSC-L origin. To evaluate 2D and 3D cell cultures growth on the surface of membranous matrices of recombinant spidroin, to estimate its non-toxicity and adhesiveness the immunohistochemistry, light time-lapse microscopy (Cell-IQ, Chip Man Technologies, Finland), laser scanning confocal microscopy (FluoView FV10i, Olympus, Japan) and raster electronic microscopy (CamScan, Japan) were incorporated.Results. Few hours after cell seeding there was active cells’ attachment to the substrate. Attached cells were characterized by rounded, oval or polygonal ordonnance. 24 hours later bipolar elongated cells and islets of migrating epithelioid cells appearance were observed. In the incubation process under gravity force the spheroids were accumulated predominantly in the central zone of the matrix, 2 hours later an active migration of spheroids surface zone epithelioid cells was registered on the membrane. After 24 hours of incubation all seeded on the surface of membranous matrix cells possessed a mesenchyme-like phenotype. Spheroids had an ability to merge limitlessly, later we observed a new microtissue formation with epithelioid cells on the surface and mesenchyme-like cells in the central area. Both solitary spheroids and merger-derived microtissue contained epithelial and mesenchymal components as well as regularly organized fibrils of extracellular matrix.Conclusions. According to aforementioned data the development of artificial cornea bioengineered cell-tissue constructions based on the technology of 3D cell spheroids cultivation derived from multipotent stem cells of the limbus and spidroin matrix presents a promising prospect requiring a further profound investigation

Исследование биосовместимости материалов для внутрироговичных линз на модели культуры клеток стромы роговицы человека

Aim. To investigate cell reaction to different materials, potentially suitable for intracorneal lens (ICL) production.Materials and methods. A plane surface (2D) corneal stromal cell culture was performed in the presence of different experimental polymer samples, such as hydroxyethylmethacrylate, oligourethanemethacrylate and polymethylmethacrylate. The dynamics of cell numbers was evaluated over culture time. Conclusion on biocompatibility was made based on obtained data.Results. In each of the experimental groups there was a trend toward a steady increase in the number of cells from the 1st to 6th day of observation, the shapes of the cell growth curves showed no toxicity of materials and their ability not to interfere with cell proliferation. Cell proliferation in the contact to hydroxyethylmethacrylate and oligourethanemethacrylate materials was statistically significantly lower (p < 0.001) than in the presence of polymethylmethacrylate, which makes a strong case for their preferential usage for implantation into the stroma of the corneal optical area. When comparing the results obtained on the 6th day, the cells in the presence of the implant of hydroxyethylmethacrylate showed significantly less tendency to proliferate, than in the presence of oligourethanemethacrylate (p < 0.001). However, these differences were statistically significant not in all days.Conclusions. The results obtained have shown the absence of toxicity in experimental material samples and their low adhesive properties with respect to the stromal cell culture, thereby confirming its potential suitability for intracorneal implantation.Цель. Изучить клеточную реакцию на различные материалы, потенциально пригодные для изготовления интракорнеальных линз.Материалы и методы. Проведено плоскостное (2D) культивирование клеток стромы роговицы человека в присутствии образцов различных опытных полимеров (гидроксиэтилметакрилат, олигоуретанметакрилат и полиметилметакрилат). В динамике оценивали количество клеток в различные сроки культивации. На основании полученных данных делали заключение о биосовместимости и адгезивных свойствах исследуемых материалов.Результаты. В каждой из экспериментальных групп отмечалась тенденция к планомерному увеличению количества клеток с 1-х к 6-м суткам наблюдения, форма кривых роста клеток указывала на отсутствие токсичности материалов и их способности не препятствовать пролиферации клеток. Пролиферация клеток в присутствии материалов гидроксиэтилметакрилат и олигоуретанметакрилат оказалась статистически достоверно ниже (р < 0,001), чем в присутствии полиметилметакрилата, что обосновывает предпочтительность их применения для имплантации в строму роговицы в оптической зоне. При сравнении полученных результатов на 6-е сутки клетки в присутствии имплантата из гидроксиэтилметакрилата проявили достоверно меньшую тенденцию к пролиферации, чем в присутствии олигоуретанметакрилата (р < 0,001). Однако данные различия были статистически достоверными не на всех сроках наблюдения.Выводы. На основании полученных результатов было показано отсутствие токсичности у опытных образцов материалов, а также их низкие адгезивные свойства по отношению к культуре клеток стромы роговицы, что подтверждает их потенциальную пригодность для интракорнеальной имплантации

One week of levofloxacin plus dexamethasone eye drops for cataract surgery: an innovative and rational therapeutic strategy

Background: Cataract surgery is the most common operation performed worldwide. A fixed topical corticosteroid-antibiotic combination is usually prescribed in clinical practice for 2 or more weeks to treat post surgical inflammation and prevent infection. However, this protracted schedule may increase the incidence of corticosteroid-related adverse events and notably promote antibiotic resistance. Methods: This International, multicentre, randomized, blinded-assessor, parallel-group clinical study evaluated the non-inferiority of 1-week levofloxacin/dexamethasone eye drops, followed by 1-week dexamethasone alone, vs. 2-week gold-standard tobramycin/dexamethasone (one drop QID for all schedules) to prevent and treat ocular inflammation and prevent infection after uncomplicated cataract surgery. Non-inferiority was defined as the lower limit of the 95% confidence interval (CI) around a treatment difference >\u201310%. The study randomized 808 patients enrolled in 53 centres (Italy, Germany, Spain and Russia). The primary endpoint was the proportion of patients without anterior chamber inflammation on day 15 defined as the end of treatment. Endophthalmitis was the key secondary endpoint. This study is registered with EudraCT code: 2018-000286-36. Results: After the end of treatment, 95.2% of the patients in the test arm vs. 94.9% of the control arm had no signs of inflammation in the anterior chamber (difference between proportions of patients = 0.028; 95% CI: 120.0275/0.0331). No case of endophthalmitis was reported. No statistically significant difference was evident in any of the other secondary endpoints. Both treatments were well tolerated. Conclusions: Non-inferiority of the new short pharmacological strategy was proven. One week of levofloxacin/dexamethasone prevents infection, ensures complete control of inflammation in almost all patients and may contain antibiotic resistance