[Possibilities of an experimental damaging effect on the retinal pigment epithelium]. / Vozmozhnosti eksperimental'nogo modelirovaniya povrezhdayushchego vozdeistviya na pigmentnyi epitelii setchatki.

PURPOSE: To simulate the damaging effect on retinal pigment epithelium (RPE) in an experiment studying the effect of human neuronal precursors (NPs). MATERIAL AND METHODS: The study was carried out on 31 rabbits (31 eyes) of the Chinchilla breed, which were divided into 3 groups: the 1st group received a subretinal injection of balanced saline solution (BSS); the 2nd group - subretinal injection of BSS with vitrectomy, displacement of the injection bladder away from the injection site using a perfluororganic compound (PFOC) and laser coagulation; the 3rd group - subretinal injection of a culture of NPs using the same method as in the group 2. All rabbits were observed for 21 days using ophthalmoscopy, optical coherence tomography (OCT) and autofluorescence (AF). RESULTS: In the 1st group, 4 out of 5 rabbits were observed to have total retinal detachment and vitreoretinal proliferative processes in the early postoperative period after subretinal injection of the BSS. In the 2nd group, OCT and AF revealed atrophy of the outer and inner layers of the retina as well as disorganization of the photoreceptors-RPE-Bruch's membrane complex in the area of injection on the 21 day after the operation. In the 3rd group, the OCT data obtained during the 21 days of observation showed that a hyperreflective zone at the level of the RPE-Bruch's membrane complex corresponding to the NPs injection site was preserved, while there was a partial loss of the outer retinal layers - but of a smaller volume compared to the BSS injection. The suggested method of subretinal injection led to a reduced number of complications: in the 1st group, postoperative complications amounted to 80%, while in the 2nd and 3rd groups - 45%. CONCLUSION: The study proposes a new method for retinal injection of BSS, which can help reduce RPE degeneration patterns and possible postoperative complications, thus increasing research efficiency. Subretinal injection of a culture of neuronal precursors derived from human induced pluripotent stem cells (iPSCs) in an experiment can serve as a universal model for studying the survival and integration of stem cells.

[Morphological and functional indicators of retinal pigment epithelium and photoreceptor apparatus in inherited retinal diseases]. / Morfofunktsional'nye pokazateli retinal'nogo pigmentnogo epiteliya i fotoretseptornogo apparata pri nasledstvennykh zabolevaniyakh setchatki.

PURPOSE: To evaluate the relationship between the morphological and functional parameters of retinal pigment epithelium (RPE) and photoreceptors (PR) in inherited retinal diseases (IRD). MATERIAL AND METHODS: The study included 52 patients (104 eyes), 23 of them with Stargardt Disease (STGD), 19 with cone-rod dystrophy (CRD), 10 with retinitis pigmentosa/pigmentary abiotrophy (RP) of comparable disease durations. All patients underwent standard and additional ophthalmological examination: fundus autofluorescence (AF), spectral optical coherence tomography (OCT), computer perimetry (CP), electro-oculography (EOG), Ganzfeld electroretinography (gERG). RESULTS: Comparison of the groups of IRD patients and groups according to the degree of RPE damage with the control group revealed an increase in differences in the EOG and gERG indicators as the area and depth of damage to the RPE and PR progressed. The patterns of changes in RPE and PR, the frequency of their occurrence with IRD in this patient sample are described. A moderate correlation was found between the amount of RPE loss and EOG light rise, as well as between the defect of the ellipsoid zone and the amplitude of α- and ß-waves, the latency of ß-wave of the gERG. Some patients showed a mismatch between a small defect of the ellipsoid zone and RPE with significant damage to the visual field and reduction of the EOG and gERG indicators. The obtained electrophysiological indicators revealed pathological changes in RPE and PR, more significant and widespread in some cases than it was shown with visualization methods. Weak and moderate correlations between visual acuity, and RPE damage and light sensitivity index with loss of ellipsoid zone were calculated. CONCLUSIONS: Modern methods of retinal examination can help obtain complete and versatile picture of morphological and functional state of the retina in IDR that supplement each other. EOG and gERG have capability to determine the degree of RPE and PR functions impairment including those cases when morphological studies are not sufficiently informative.

Association between Disturbances in Polyunsaturated Fatty Acid Metabolism and Development of Oxidative Stress during Experimental Diabetes Mellitus.

We studied the effect of streptozotocin-induced diabetes mellitus on the level of glycemia and some other indices of lipid metabolism, including fatty acid metabolism and LPO intensity, during the development of diabetes mellitus in rats. Even at the early terms of diabetes development, hypertriglyceridemia and hypercholesterolemia were accompanied by changes in the blood content of fatty acid (at the expense of ω3 and ω6 fatty acids) that persisted throughout the observation period. Intensification of LPO against the background of suppressed activity of antioxidant enzymes and reduced level of ω3 fatty acids attested to the development of oxidative stress. These data attest to antioxidant property of ω3 fatty acids, which is seen from positive correlations between these fatty acids and activity of antioxidant enzymes.

[Possibilities of treating retinal diseases in patients with damaged retinal pigment epithelium]. / Vozmozhnosti lecheniia zabolevanii setchatki, soprovozhdaiushchikhsia povrezhdeniem retinal'nogo pigmentnogo épiteliia.

Retinal diseases associated with damage to retinal pigment epithelium (PPE) are the most frequent causes of irreversible loss of vision in adults. Since there is no therapeutic treatment available that could repair RPE and its connections with the adjacent photoreceptors, the review focuses on various methods of surgical treatment. One of the most promising methods at present is the use of stem cells derivatives. Results of numerous experimental and clinical trials show that use of human induced pluripotent stem cells in the treatment of degenerative diseases of the retina can be considered effective and promising.

[Phenotype-genotype correlations in patients with inherited retinal diseases with p.G1961E mutation in the ABCA4 gene]. / Kliniko-geneticheskie korreliatsii u patsientov s nasledstvennymi zabolevaniiami setchatki pri mutatsii p.G1961E v gene AVSA4.

PURPOSE: To evaluate phenotype-genotype correlations in patients with inherited retinal diseases (IRD) with mutation p.G1961E in the ABCA4 gene. MATERIAL AND METHODS: The study included 20 patients with p.G1961E mutation in the heterozygous state in the ABCA4 gene who underwent complete ophthalmic examination, as well as high-performance parallel sequencing of the coding sequences and adjacent areas of the introns of the ABCA4, ELOVL4, PROM1, CNGB3 genes. RESULTS: The p.G1961E mutation was detected in heterozygous state with missense mutations, splice site mutations, a frameshift duplication, and a nonsense mutation in 18 patients, a second mutation was not detected in 2 patients. The duration of the disease in 4 patients was 2-5 years, which made it impossible to assess the morphofunctional changes in dynamics. In 13 of the 16 patients with IRD duration of 29±14 years and p.G1961E mutation in the ABCA4 gene the course of the disease was relatively mild: visual acuity of 0.15±0.07, loss of visual acuity averaging 0.037±0.019 per year, absolute/relative scotoma within 5-20°, and 3.52±1.21 mm loss of ellipsoid photoreceptor zone in the macular area according to OCT. In 3 patients, including one without a second mutation in the ABCA4 gene, better pronounced changes were revealed. Multifocal electroretinogram was altered in all 20 cases. In 7 of the 8 patients with p.G1961E in the heterozygous state in combination with complex mutation p.[L541P;A1038V], as well as in 2 patients without a second mutation, full-field electroretinography (Ganzfeld; ffERG) had changes (abnormalities) of varying intensity. CONCLUSION: A frequent mutation in the ABCA4 gene - p.G1961E - is associated with a relatively mild course of IRD in 81% of cases, even in the presence of a second, severe mutation. However, in rare cases a more severe phenotype of the IRD in patients with p.G1961E mutation can be observed, which may be associated with other genetic factors. In patients with the p.G1961E mutation in heterozygous state with p.[L541P;A1038V], ffERG changes (abnormalities) were revealed.

[Clinical polymorphism of splice site mutations in the ABCA4 gene]. / Polimorfizm klinicheskikh proiavlenii pri mutatsiiakh saita splaisinga v gene AVSA4.

ABCA4 is one of the main genes whose mutations are associated with various inherited retinal diseases (IRD) such as Stargardt disease, cone dystrophy, cone-rod dystrophy, and retinitis pigmentosa. The severity of retinal dystrophy phenotype may be related to the degree of mutation pathogenicity, which depends on the localization in various regulatory regions of the gene and the effect on the amino acid composition of the protein molecule. The article describes two clinical cases of patients with splice site mutations in the compound heterozygous state with missense mutations in the ABCA4 gene with various phenotypic manifestations, which demonstrate the importance of molecular genetic analysis in patients with IRD. Such analysis allows determination and accumulation of data on phenotype-genotype correlations that can help predict the disease course.