[Experimental stem cell replacement transplantation in retinal pigment epithelium atrophy]

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 Engineering», 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.

[Bilateral occlusion of retinal vessels in Waldenstrom's disease (a case study)]

The article describes a clinical case of bilateral occlusion of retinal vessels in a patient with Waldenstrom's disease - a rare lymphoplasmocytic tumor of the bone marrow characterized by a complex of syndromes, among which the syndrome of blood hyperviscosity dominates. Comprehensive clinical, instrumental and laboratory examinations revealed that besides the syndrome of blood hyperviscosity the patient also had loci of cerebral ischemia (according to magnetic resonance imaging), ocular hypoperfusion with severe deficiency of retinal and choroidal blood flow (according to Doppler methods) indicating the presence of ocular ischemic syndrome. Since bilateral occlusion of retinal vessels without concomitant vascular and/or systemic pathology is rare, patients with such diagnosis should be referred to a hematologist.

[The effect of intravitreally administered angiogenesis inhibitor on the concentration of angiotensin-converting enzyme in the blood serum and lacrimal fluid in patients with diabetic macular edema]

BACKGROUND

Diabetic retinopathy (DR) is one of the more serious complications of diabetes and the main cause of blindness among working-age individuals. In recent years, information has emerged on the possible role of the renin-angiotensin system (RAS) in the pathogenesis of DR, and DR's possible connection with the system of pro-angiogenic factors.

AIM

To study the impact of anti-angiogenic therapy on systemic and local concentrations of angiotensin-converting enzyme (ACE), a key component of RAS, for patients with diabetic macular edema (DME).

MATERIAL AND METHODS

The concentration of ACE in the lacrimal fluid and blood serum in 10 patients (20 eyes) with DME was determined before and after intravitreal injection (IVI) of ranibizumab. The comparison group consisted of 7 patients (14 eyes) with age-related macular degeneration (AMD). The control group consisted of 10 healthy individuals (20 eyes). All groups were comparable in age and sex. The concentration of ACE was determined by enzyme immunoassay. The main group was examined four times: before IVI of ranibizumab, and then one week, two weeks and one month after IVI of ranibizumab. The comparison group was examined before, and then one week after, IVI of ranibizumab.

RESULTS

In patients with DME, there was an initial 1.8-fold increase in the concentration of ACE in the lacrimal fluid of both eyes. A week after IVI of ranibizumab, the concentration of ACE in the lacrimal fluid began to decrease, reaching the control level after two weeks, and remaining there one month after IVI of ranibizumab. Initially, the concentration of ACE in the blood serum in patients with DME was 2.2 times lower than the control level. After IVI of ranibizumab there was an increase in the concentration of ACE in the blood serum, but by the end of the observation, the indicators continued to remain well below the control level. In patients with AMD, the initial concentration of ACE in the lacrimal fluids was not elevated; the concentration of ACE in the lacrimal fluids decreased 1.4 times one week after IVI of ranibizumab. The concentration of ACE in the blood serum of the patients with AMD was initially 25% lower than the control level, and essentially did not change after IVI of ranibizumab. СONCLUSIONS: Changes in the concentration of ACE in patients with DME may be a new prognostic criterion for the development of DME for patients with diabetes. These changes in the concentration of ACE, in the context of antiangiogenic therapy, indicate an interaction between the renin-angiotensin and angiogenic systems. Similar changes that were observed after IVI of ranibizumab in patients with AMD confirm the mutual influence of these two systems. The data presented in this study open up prospects for finding new pathways of pathogenic therapy for diabetic macular edema and diabetes.

[Role of infection in the pathogenesis of age-related macular degeneration]

AIM

to study the role of infectious agents in the development and progression of AMD by means of serodiagnostic assay for a complex of ophthalmotropic and opportunistic infections.

MATERIAL AND METHODS

The study enrolled 61 patients (23 men, 38 women) aged 43-68 years and diagnosed in accordance with AREDS classification of AMD. Serodiagnostic tests were performed for 11 infections with the purpose of identifying antigen-specific antibodies in the serum.

RESULTS

Activation markers of one or several infections were detected in most of the patients with AMD.

CONCLUSION

Herpes viruses (HSV1 and CMV) along with some opportunistic pathogens are important factors in the pathogenesis of AMD, thereby, specific treatment should be performed in these patients.