[Pathogenetic role of multifunctional protein alpha-2-macroglobulin and its activity in tears and serum in age-related macular degeneration and proliferative diabetic retinopathy]. / Patogeneticheskaya rol' polifunktsional'nogo belka α2-makroglobulina i ego aktivnost' v sleze i krovi pri vozrastnoi makulyarnoi degeneratsii i proliferativnoi diabeticheskoi retinopatii.

Alpha-2-macroglobulin (α2-MG) is a multifunctional protein involved in neurodegeneration, inflammation and neovascularization, which are key processes in the pathogenesis of age-related macular degeneration (AMD) and proliferative diabetic retinopathy (PDR). AMD and PDR are two of the main causes of vision loss and blindness, are difficult to treat, and are generally diagnosed at the stage of irreversible changes. PURPOSE: This study estimates the activity of α2-MG in the blood serum and tears of patients with AMD and PDR in order to reveal the relation of its levels with the intensity of the pathological process in the retina. MATERIAL AND METHODS: The study included 17 patients (34 eyes) with AMD, 15 patients (30 eyes) with PDR, and 15 healthy adults (30 eyes) of the similar age. The activity of α2-MG in serum and tears was measured enzymatically using the specific substrate N-benzoyl-DL-arginine-p-nitroanilide (BAPNA). RESULTS: The activity of α2-MG in tears of patients with AMD was on the average 3.5 times higher than in healthy controls, and in patients with PDR - 1.5 times higher. Patients with AMD at the submacular fibrosis stage showed decreased α2-MG activity in tears. The activity of α2-MG in serum of patients with AMD and PDR was on the average 25% higher than in healthy persons. No correlation was revealed between serum and tear levels of α2-MG activity. CONCLUSION: This study revealed for the first time that in AMD and PDR the activity of α2-MG in tears is increased, and that in AMD the increase is higher than in PDR. An increase of α2-MG activity in serum confirms the presence of systemic inflammation. Absence of correlation between the serum and tear activity of α2-MG confirms its local origin. The high level of α2-MG activity in tears reflects the presence of an active destructive process in the retina, justifying its further investigation as a predictor of AMD and PDR course, as well as an indicator of therapy effectiveness.

[Changes of a2-macroglobulin activity and endothelin-1 concentration in tears of rabbits after transplantation of retinal pigment epithelium cells derived from the induced pluripotent stem cells]. / Izmenenie urovnia a2-makroglobulina i éndotelina-1 v sleznoi zhidkosti krolikov posle transplantatsii kletok retinal'nogo pigmentnogo épiteliia, differentsirovannykh iz indutsirovannykh pliuripotentnykh stvolovykh kletok.

Retinal diseases accompanied with the dysfunction or death of the retinal pigment epithelial (RPE) cells are widespread, hard to treat, and appear to be a leading case of visual loss and blindness among the persons older than 55 years. Transplantation of RPE cells derived from the induced pluripotent stem cells (IPSC-RPE) is a promising method of therapy for these diseases. To ensure the transplant survival instant follow-up is required. It can be based on biochemical analyses of tear fluid that can be easily non-invasively collected. For the post-transplantation process monitoring we have choosen such polyfunctional bioregulators as α2-macroglobulin (α2-MG) and endothelin-1 (ET-1). RPE atrophy in New Zealand Albino rabbits was modeled via the subretinal injection of bevacizumab. IPSC-RPE in suspension or as a monolayer on the scaffold were transplanted subretinally 1 month after the injection. α2-MG activity and ET-1 concentration in tears were estimated during the first month and after 2, 3 and 7 months after transplantation. On the 7-14 days after transplantation α2-MG activity increased in tears of the both operated and controlateral eye probably as a reaction on the corticosteroid therapy. In 50% rabbits there was one more increase after 2-3 months that could be due to the immune inflammation. Concentration of ET-1 in tears decreased dramatically on the 7-14 days and 7 months after transplantation, and it could have an influence upon the retinal vassal tone. The data obtained show that estimation of bioregulators in tears can help monitoring local metabolic processes after RPE transplantation that is necessary for the opportune, reasonable and focused medicamental correction of post-transplantation process.

[Experimental stem cell replacement transplantation in retinal pigment epithelium atrophy]. / Zamestitel'naya transplantatsiya stvolovymi kletkami pri atrofii retinal'nogo pigmentnogo epiteliya v eksperimente.

PURPOSE: To develop and evaluate the results of the modified surgical technique for transplantation of retinal pigment epithelium (RPE) differentiated from human induced pluripotent stem cells (iPSC-RPE) in the form of a cell suspension into the subretinal space of rabbits with previously induced RPE atrophy. MATERIAL AND METHODS: The study was conducted on 10 New Zealand albino rabbits (20 eyes). One month after modeling RPE atrophy and retinal degeneration, rabbits were subjected to subretinal transplantation of iPSC-RPE cells in the form of a cell suspension. To prevent reflux of iPSC-RPE into the vitreal cavity, the injection site was sealed with 2-3 drops of autologous platelet-rich plasma (PRP). All rabbits underwent spectral optical coherence tomography (SOCT) and autofluorescence studies on the Heidelberg Spectralis system («Heidelberg Engineering¼, Germany). Enucleated animal eyes were studied with morphological and immunohistochemical methods. RESULTS: In this study we developed and evaluated a modified surgical technique of transplantation of iPSC-RPE in the form of a cell suspension into the subretinal space of rabbits with induced RPE atrophy. It was found that the use of PRP helps seal the defect and prevents cell suspension reflux into the vitreous cavity, effectively minimizing intra- and postoperative complications. Morphological in vivo study and examination of histological sections showed that implantable iPSC-RPEs were correctly integrated and adhered to the choroid in the surgery site. Immunohistochemical analysis involving fluorescence-marked antibodies confirmed the survival of iPSC-RPE integrated into the retina of model animals. CONCLUSION: This method improves the technology of iPSC-RPE transplantation on preclinical stages of the study, revealing new prospects in the treatment of degenerative diseases of the retina and the possibility of a personalized approach.

[Current view on the issue of insufficient effectiveness of anti-VEGF therapy for age-related macular degeneration]. / Sovremennyi vzglyad na problemu nedostatochnoi effektivnosti antiangiogennoi terapii vozrastnoi makulyarnoi degeneratsii.

Due to the significant medical and social importance of neovascular (wet) age-related macular degeneration (wAMD), increasing the effectiveness of anti-VEGF therapy used to treat this disease is one of the high-priority problems in modern retinology. This article focuses on pathobiological aspects and clinical manifestations of incomplete responses to anti-VEGF therapy of wAMD, considers the proposed ways to improve the terminology and classification of responses to therapy, as well as the assessment of its correctness and effectiveness of the treatment. It also discusses the available ways to optimize anti-VEGF therapy and define the criteria of its termination in cases when the treatment proves to be futile.

Features of Local Expression of Genes of Immune Response Cytokines and Trophic and Vasoregulatory Factors in Modeling of Retinal Pigment Epithelium Atrophy.

Local expression of genes encoding IL-1ß, IL-18, MCP-1/CCL2, PEDF, VEGF-A, and ZO-1 in the retina-retinal pigment epithelium-chorioidea tissue complex was studied in healthy rabbits and animals with simulated retinal pigment epithelium atrophy. Retinal pigment epithelium atrophy was modeled by single subretinal injection of 0.01 ml 0.9% NaCl (group 1; n=17) or 0.01 ml solution containing angiogenesis inhibitor bevacizumab in a dose of 0.025 mg (group 2; n=18). The gene expression was evaluated by reverse transcription PCR. In 27.7% cases, atrophic changes in the fundus were accompanied by a significant increase of IL-1ß gene expression and in more than 50% cases by an increase in VEGF-A and MCP-1/CCL2 mRNA levels. These factors contribute to an increase in the permeability of the blood-retina barrier and abolition of the immune privilege of the posterior eye segment, which should be taken into account when testing invasive approaches, in particular, for approbation of various options of replacement therapy with retinal pigment epithelium stem cells and development and use of neuroprotectors and drugs of targeted action.

[Anti-VEGF therapy for neovascular age-related macular degeneration: causes of incomplete response]. / Anti-VEGF-terapiya neovaskulyarnoi vozrastnoi makulyarnoi degeneratsii: prichiny nedostatochnoi effektivnosti.

Neovascular age-related macular degeneration (nAMD) is one of the leading causes of decreased vision in the elderly population in many countries, including Russia. Anti-VEGF therapy is undoubtedly the «gold standard¼ of treatment for the disease, but its use in different patients is known to produce results with significant interindividual differences. This article reviews modern ideas about the clinical assessment of the degree of response to anti-VEGF therapy, possible reasons for its insufficient effectiveness (clinical, pharmacological, or related to nAMD pathogenesis), discusses the potential applications of the existing therapeutic strategies, and considers the prospects for the emergence of new strategies that could be used for solving that problem.

[Electroretinographic signs of retinal remodeling after experimental induction of retinal pigment epithelium atrophy]. / Elektroretinograficheskie priznaki remodelirovaniya setchatki posle induktsii atrofii retinal'nogo pigmentnogo epiteliya v eksperimente.

Various animal models of atrophy of retinal pigment epithelium (RPE) are created in order to study certain aspects of geographical atrophy in humans. To study the effects of new methods of therapy, it is necessary to determine the objective functional markers of structural changes in the retina. PURPOSE: To determine the alterations in activity of the retina that characterize its remodeling in induction of RPE atrophy. MATERIAL AND METHODS: Full-field electroretinograms (ERG), pattern ERG, and multifocal ERG were recorded according to the ISCEV standards from the right eyes of twenty rabbits of the New Zealand albino breed 6-7 weeks after induction of RPE atrophy by subretinal administration of 0.9% sodium chloride or bevacizumab solution. RESULTS: Characteristic electroretinographic signs of RPE atrophy and retinal remodeling are described. Changes in ERG indicate a predominant inhibition of the functional activity of photoreceptors compared with bipolar cells, which objectively reflects an impairment of their metabolism associated with RPE pathology. With the injection of bevacizumab, a sharp weakening of the functional symbiosis of Mueller cells with bipolar cells was observed. According to pattern ERG, the function of the retinal ganglion cells was reduced. The reaction of the paired eyes after induction of RPE atrophy included a moderate decrease in the amplitude of b-wave of photopic ERG and activation of glia-neuronal relationships. CONCLUSION: Subretinal injections of 0.9% sodium chloride and bevacizumab trigger changes in the retina that reflect specific remodeling of retinal neurons of the second and third orders, which characterizes the used models of RPE atrophy.

[Electroretinography in the diagnosis and monitoring of treatment for neovascular age-related macular degeneration: Communication 1].

The pathophysiological mechanisms responsible for the development of choroidal neovascularization (CNV) in age-related macular degeneration (ARMD) still remain to be little studied and clinical electrophysiology that has a wide spectrum of objective studies plays a great role in the assessment of regularities of retinal functional changes in this disease. Recording of different types of electroretinograms (ERG) from the ISCEV standards and multifocal ERG is most extensively used to characterize CNV. The review considers the pattern of ERG changes in normal physiological aging and the specific features of suppressed retinal electrogenesis in neovascular ARMD. The diagnostic capacities of different electroretinographic methods, their disadvantages and limits in the evaluation of retinal functions in patients with CNV are compared.

[Electroretinography in the diagnosis and monitoring of treatment for neovascular age-related macular degeneration: Communication 2].

Electroretinography is an informative tool in evaluating retinal function in age-related macular degeneration (ARMD) and in monitoring the treatment of choroidal neovascularization (CNV). The review gives the results of electroretinographic studies in the monitoring of CNV, by using photodynamic therapy (PDT) and angiostatic agents and in combined PDT and anti-VEGF therapy. The regularities of retinal functional changes in the early and late periods after mono- and combined therapy are considered. The informative value of various electroretinographic studies was compared in the evaluation of retinal functional changes after therapy and in the prediction of its efficiency. Multifocal electroretinography is today of the greatest value among other conventional methods; however, there is a need for searching for new objective indicators that enable assessment of progress in the treatment of neovascular ARMD and optimization of indications for this or that treatment, particularly when new and expensive technologies of treating CNV emerge.

[Photodynamic therapy with visudine in combination with intravitreal kenalog in the treatment of choroidal neovascularization].

There are current tendencies in the use of photodynamic therapy (PDT) in combination with intravitreal injection of long-acting corticosteroids. Kenalog was intavitreally injected in patients with abnormal myopia (4 eyes), multifocal choroiditis (3 eyes), and age-related macular degeneration (6 eyes), and idiopathic choroidal neovascularization (CNV) (1 eye) 10-14 days before PDT. All the above cases were characterized by a severe clinical course with significantly diminished visual function, and evident exudative-hemorrhagic manifestations. A 2-5-line vision increase and bleeding resorption were observed in the patients 1-2 months after PDT. The results of optical coherent tomography suggest a significant reduction or disappearance of exudative manifestations (retinal edema, detachments of the neuroepithelium or pigment epithelium). Fluorescence angiography revealed decreased or ceased dye diffusion in the CNV areas at the late stages of the study. The findings suggest the efficiency of combined therapy for CNV that can improve visual prognosis significantly in patients after PDT.