Optical coherence tomography angiography allows detection of tumor`s own vessels with characteristics of their vascularization in early choroidal melanoma and circumscribed choroidal hemangioma. Increasing the frequency of detection of tumor`s own vessels will make possible early differential diagnostics of a malignant or benign tumor and will help establish adequate conserving therapy.

The study revealed no negative effects of the angiogenesis inhibitor ranibizumab on retinal microcirculation or ocular blood flow. The registered changes in blood flow may indicate improvement of hemodynamic parameters after resorption of macular edema.

BACKGROUND. Diabetic macular edema (DME) is a microvascular complication of diabetic retinopathy. One of the key roles in the pathogenesis of DME may belong to the components of rennin-angiotensin and kallikrein-kinin systems: bradykinin (Bk) and angiotensin-converting enzyme (ACE).PURPOSE. To determine the Bk and ACE concentration and ACE activity in serum of patients with proliferative diabetic retinopathy (PDR) and to estimate the significance of these parameters for the early diagnostic and prognosis of DMO.MATERIALS AND METHODS. Serum was collected from the 2 groups of patients with II type diabetes. Group I (n=9) had DME, group II (n=27) had PDR without DME. Control group (n=14) consisted of adult volonteers without diabetes and ophthalmic diseases. Concentration of Bk and ACE was measured using ELISA kits, ACE activity was determined enzymatically with specific fluorogenic substrate.RESULTS. Concentration of Bk in serum of patients without DME did not differ from one in controls (12,00 (9,70; 12,40) pg/ml) while all patients with DME had Bk level of 14,69 (13,68; 16,78) pg/ml that was significantly higher (p<0,01). In patients without DME ACE concentration (88,60 (77,30; 97,45) ng/ml) and ACE activity (6,8 (5,1;7,1) nmol/min·ml) were higher than normal (p<0,01) while in the case of DME concentration of ACE increased (77,36 (70,24; 86,29 ng/ml, p<0,01) and activity remained normal. The Bk/ACE concentrations ratio decreased in patients without DME and increased in those having DME.CONCLUSION. Patients with DME have increased Bk concentration along with nearly normal ACE concentration that indicate predominance of Bk synthesis over its degradation that may lead to the DME development. The Bk/ACE ratio decrease in patients with uncomplicated PDR and increase significantly in ones with DME. It means that determination of Bk in serum of patients with PDR may be used for the prediction of DME development. The Bk/ACE concentrations ratio may be even more informative.

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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 DRs 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.