[The role of endothelin-1 in the pathogenesis of familial exudative vitreoretinopathy]. / Rol' endotelina-1 v patogeneze semeinoi ekssudativnoi vitreoretinopatii.

Familial exudative vitreoretinopathy (FEVR) is a rare hereditary disease characterized by pathological retinal vascularization with a progressive and variable course. The mechanisms of disease progression remain unclear. One substance that plays an important role in the pathogenesis of retinal vascular diseases is endothelin (ET). It was found that tissue hypoxia enhances the expression of the gene encoding ET-1, and ET-1 can be locally produced in the eye. PURPOSE: The study evaluates the possible role of endothelin-1 in the pathogenesis of FEVR. MATERIAL AND METHODS: The study included 85 patients with FEVR aged from 1 months to 17 years who were examined in Helmholtz National Medical Research Center of Eye Diseases. The concentration of ET-1 was evaluated in 19 patients with FEVR in the blood serum (n=17), lacrimal fluid (n=18) and 16 patients from the control group. RESULTS: The median of ET-1 in the lacrimal fluid in patients with FEVR was 13.74 pg/mL, respectively, which exceeded the same indicator of the control group 4.66 pg/mL by 2.5 times (p<0.001). The median of ET-1 in the blood serum exceeded the control group by 2.4 times (21.61 pg/mL and 9.21 pg/mL, respectively, p<0.001). CONCLUSIONS: An increase in the concentration of ET-1 in the lacrimal fluid and blood serum of patients with FEVR in comparison with the control group indicates its involvement in the pathogenesis of the disease.

Enalaprilat as a new means of preventing the development of retinopathy of prematurity.

In a rat model of experimental retinopathy of prematurity (ROP), the safety of enalaprilat and its effect on the level of angiotensin-converting enzyme (ACE) and angiotensin-II (AT-II) in the vitreous body and retina were investigated. The study was performed on 136 newborn Wistar rat pups divided into 2 groups: group A - experimental (animals with ROP, n=64) and group B - control (n=72). Each group was further divided into 2 subgroups: A0 and B0 (n=32 and n=36, respectively) - animals that did not receive injections of enalaprilat, and A1 and B1 (n=32 and n=36, respectively) - animals treated with daily intraperitoneal (i.p.) injections of enalaprilat (0.6 mg/kg of body weight). This treatment started on day 2 and lasted either to day 7 or to day 14 in accordance with the therapeutic scheme. Animals were taken out of the experiment on day 7 and day 14. In samples of the vitreous body and retina, the content of ACE and AT-II was determined by enzyme immunoassay. On day 7 in subgroups A1 and B1 the levels of ACE and AT-II in the vitreous did not differ, while on day 14 were lower than in subgroups A0 and B0, respectively. Changes in the parameters studied in the retina were somewhat different from those found in the vitreous body. On the seventh day, the level of ACE in the retina of animals of subgroup B1 did not differ significantly from subgroup B0, and in subgroup A1 it was increased compared to subgroup A0. On day 14, its significant decrease was noted in subgroups A1 and B1 as compared with subgroups A0 and B0. At the same time, the level of AT-II in the retina of rat pups of subgroup B1 was lower than in subgroup B0, both on day 7 and day 14. On day 7, the concentration of AT-II, as well as the concentration of ACE, increased in subgroup A1 as compared to subgroup A0. On day 14, this parameter in subgroup A1 was significantly lower as compared to subgroup A0, but significantly higher than in subgroup B1. It should be noted that i.p. injections of enalaprilat, increased a death rate of animals of both groups. The use of enalaprilat, starting from the preclinical period of the ROP development, led to a decrease in the activity of the renin-angiotensin system (RAS) in ROP animals at the onset of retinopathy in the experimental model used. This opens up prospects for considering enalaprilat as a means of preventing the development of this pathology; however, the recognized high toxicity of the drug requires further studies and correction of the timing of its administration and dosage in order to achieve a balance of efficacy and safety of use in order to prevent the development of ROP in children.

[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.

[Bradykinin and angiotensin-converting enzyme in serum of patients with diabetic retinopathy and the prognosis of diabetic macular edema development (pilot study)].

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.

Molecular Mechanisms and Clinical Manifestations of Catecholamine Dysfunction in the Eye in Parkinson's Disease As a Basis for Developing Early Diagnosis.

This review provides information on the non-motor peripheral manifestations of Parkinson's disease (PD) associated with a pathology of the visual analyzer and the auxiliary apparatus of the eye. The relationship between neurodegenerative processes that take place in the brain and in the eye opens new prospects to use preventive ophthalmologic examination to diagnose PD long before the characteristic motor symptoms appear. This will encourage the use of neuroprotective therapy, which stops, or at least slows down, neuronal death, instead of the current replacement therapy with dopamine agonists. An important result of an eye examination of patients with PD may be a non-invasive identification of new peripheral biomarkers manifesting themselves as changes in the composition of the lacrimal fluid.

[The role of the endothelin system in the pathogenesis of eye diseases]. / Rol' éndotelinovoi sistemy v patogeneze glaznykh boleznei.

The endothelin system (ES) plays a complex role in the pathogenesis of various eye diseases as a local regulator of vascular tone as well as many other physiological processes. Components of ES - endothelins and their receptors - can be found nearly in all cellular structures of the eye, their concentration increases in the presence of many eye diseases. In glaucoma, ES is involved in the mechanisms of eye hypertension by influencing the secretion and outflow of aqueous humor. The increase of endothelin level leads to the decrease of perfusion pressure, hypoxia, astrocyte proliferation, increase of density and rigidity of lamina cribrosa, apoptosis of neural cells, and has a profibrogenic effect. In retinal pathology, increase of endothelins disturbs autoregulation of retinal blood vessels changing the neurovascular interactions, breaks intercellular contacts in the retina, promotes neoangiogenesis. In diabetic retinopathy, ES contributes to the development of microangiopathy and proliferative vitreoretinopathy. The review discusses the possibility of correcting ES activity in the eye with medications by influencing its synthesis, cleavage and receptor binding.

Possibilities and perspectives of using cardiac contractility modulation in patients with chronic heart failure and atrial fibrillation.

Heart failure is one of the main health care problems all over the world. Although, there are many drugs with proven effectiveness and hi-tech devices, there is a continuous process of searching new possibilities in heart failure prophylaxis going on because of huge economic burden and impact on life quality. Developing of atrial fibrillation in heart failure patients increases the risks of hospitalization and all-cause mortality. Appearance of new Optimizer Smart® system of cardiac contractility modulation is a perspective way of treatment in patients with heart failure and atrial fibrillation, who are not a candidate or have not got a good result from cardiac resynchronization therapy (CRT).

Tear Fluid Catecholamines As Biomarkers of the Parkinson's Disease: A Clinical and Experimental Study.

An important approach to an early diagnosis of Parkinson's disease (PD) is screening for peripheral biomarkers in patients at the early clinical stage. In this study, we evaluated catecholamine concentration changes in the tear fluid of untreated PD patients as biomarkers. Norepinephrine and dopamine concentrations in the tear fluid of patients were found to increase compared to those in age controls, which was especially pronounced on the side where motor symptoms appeared. On the contrary, the epinephrine concentration in the tear fluid of patients was reduced bilaterally. Since there was no reason to consider the markers found in the clinical stage of PD as markers of the preclinical stage, we additionally studied the tear fluid composition in mouse neurotoxic models of PD preclinical and clinical stages. The norepinephrine concentration in the tear fluid of mice from the clinical stage model was found to be higher than that in controls; in the preclinical stage model, the norepinephrine concentration had a tendency to increase. Therefore, both PD patients and mice from PD preclinical and clinical stage models manifest unidirectional changes in their tear fluid compositions, which may be considered as promising biomarkers for the development of early diagnosis.

Biochemical and Functional Changes in the Eye As a Manifestation of Systemic Degeneration of the Nervous System in Parkinsonism.

Parkinson's disease (PD) is a systemic neurodegenerative condition caused by the death of dopaminergic neurons of the nigrostriatal system of the brain. This disease is diagnosed after most neurons have already been lost, which explains the low efficiency of treatment. Hope for increasing treatment efficiency rests in the development of new strategies for early diagnosis of PD based on a search for peripheral markers that appear as early changes in non-motor functions. Since impairment of the visual function is one of the manifestations of PD, the purpose of our work was to identify biochemical and physiological changes in a mouse's eye and eyelid in models of preclinical (presymptomatic) and clinical (symptomatic) stages of PD. We found that the norepinephrine, dopamine, and serotonin levels in the mouse eye reduced not only in the model of the early clinical stage, but also in the model of preclinical stage, an indication that pathological changes in the monoaminergic systems of the brain had affected the eye even before the motor disorders emerged. Moreover, in both models of PD, mice had increased intraocular pressure, indicating the development of both metabolic and functional impairments, which can be used as diagnostic markers. Unlike in the eye, the serotonin level in the eyelid was increased in mice at both parkinsonism stages and in presymptomatic mice to a much higher extent than in symptomatic ones. Given that serotonin is involved in the regulation of lacrimal glands of the eyelid, an increase in its level in parkinsonian mice should alter the composition of tear fluid, which could serve as a diagnostic marker of early stage of PD. Thus, the changes in the metabolism of monoamines in the eye and eyelid observed in mice at the early stage of parkinsonism are accompanied by changes in the function of these structures and, therefore, can be used as diagnostic markers of the early stage of PD.

[Endothelins and dopamine levels in tears for assessment of neurovascular disorders in glaucoma]. / Éndoteliny i dofamin v sleznoi zhidkosti v otsenke neirovaskuliarnykh narushenii pri glaukome.

PURPOSE: To estimate the possibility of detection of neurovascular ocular disorders in glaucoma by assessing the content of catecholamines and endothelins in lacrimal fluid. MATERIAL AND METHODS: The study included 47 patients with primary open-angle glaucoma (POAG). Tear eluate was analyzed by high performance liquid chromatography (HPLC) for catecholamines concentrations, and enzyme-linked immunoassay (ELISA) was used for evaluation of endothelins content. RESULTS: Endothelin-1 (ET-1) and big endothelin (bET) content in tears of patients with POAG was higher than in healthy controls. Concentration of dopamine (DA) in tears was lower and concentrations of L-dioxyphenylalanine and dihydroxyphenylacetic acid had a tendency for decrease. Noradrenaline content was equal in patients with POAG and controls. Adrenaline was not detected in any tear samples. CONCLUSION: Multidirectional changes of endothelins and DA levels in tears of patients with POAG was found. The increased concentration of ET-1 and its precursor bET promote vasoconstriction and decrease of aqueous humor outflow. The decrease of DA concentration is typical for neurodegenerative processes. Estimation of DA and endothelins concentrations in tears can enable early detection of neurovascular disorders in glaucoma patients and help evaluate their severity.

Comparative Study of the Severity of Renal Damage in Newborn and Adult Rats under Conditions of Ischemia/Reperfusion and Endotoxin Administration.

Oxidative kidney injury was compared in newborn and adult rats under conditions of ischemia/reperfusion and in experimental model of systemic inflammation induced by endotoxin (LPS of bacterial cell wall) administration. Oxidative stress in the kidney accompanied both experimental models, but despite similar oxidative tissue damage, kidney dysfunction in neonates was less pronounced than in adult animals. It was found that neonatal kidney has a more potent regenerative potential with higher level of cell proliferation than adult kidney, where the level proliferating cell antigen (PCNA) increased only on day 2 after ischemia/reperfusion. The pathological process in the neonatal kidney developed against the background of active cell proliferation, and, as a result, proliferating cells could almost immediately replace the damaged structures. In the adult kidney, regeneration of the renal tissue was activated only after significant loss of functional nephrons and impairment of renal function.

[Ophthalmic disorders as a manifestation of Parkinson's disease]. / Patologiia organa zreniia kak odno iz proiavlenii bolezni Parkinsona.

Parkinson's disease is a severe neurodegenerative disease accompanied with the degeneration of dopaminergic neurons in the central and peripheral nervous system. The diagnosis of Parkinson's disease can still be made only on the stage of irreversible and nearly total degeneration of the nigrostriatum dopaminergic system and exhaustion of brain compensatory mechanisms that explains the low efficacy of therapy. Ophthalmic pathology is one of the nonmotor symptoms of Parkinson's disease. This can be explained firstly by the fact that eye is a 'peripheral part of brain' and secondly by the involvement of dopaminergic neurons (dopamine-producing cells) that are subject to the selective degeneration during Parkinson's disease in the regulation of visual function in the eye and brain. Dopaminergic neurons and dopamine receptors are present in all structures of the eye. Parkinson's disease cause abnormalities not only in the retina but in the whole optic tract and can be considered as peripheral manifestations of the disease that precede the well-known motor dysfunctions. This review describes ophthalmological symptoms of Parkinson's disease, possible pathophysiological mechanisms of their development, optical disorders in experimental models of Parkinson's disease and also the perspectives of experimental and clinical studies of visual disorders for the development of preclinical diagnosis of Parkinson's disease.

Effects of hydroxypyridine derivatives mexidol and emoxypin on the reparative processes in rabbit eye on the models of corneal epithelial defect and conjunctival ischemia.

Deepithelialization of the cornea (diameter 7 mm) was performed in rabbits and the rate of defect epithelialization was evaluated. Conjunctival ischemia was modeled by application of graduated alkaline burn. Antioxidant activity and content of nitrates and nitrites was measured in the tear fluid before and after burn by chemiluminescence and Griess methods, respectively. Emoxypin and mexidol promoted healing of corneal epithelial defect at the stage of epitheliocyte migration to the defect area and at the stage of their proliferation, respectively. After treatment with both agents, the area of conjunctival ischemia decreased more rapidly, but the efficiency of mexidol was higher. Antioxidant activity and content of products of NO metabolism in tear fluid decreased after burn. Mexidol, but not emoxypin, increased these parameters. Thus, mexidol and emoxypin have different effects on corneal epithelialization and conjunctival ischemia and effects of mexidol are more pronounced.

[Level of tear endothelin-1 and plasminogen in patients with glaucoma and proliferative diabetic retinopathy].

A considerable tear endothelin-1 increase (2-3 times) has been found in patients with primary open-angle glaucoma and proliferative diabetic retinopathy. Patients with proliferative retinopathy also showed an increase of plasminogen level in tear fluid and a tendency of a similar increase in blood serum. No correlation between endothelin-1 and plasminogen levels in these pathologies was established. Tear endothelin-1 and plasminogen measurement could be used as an informative and non-invasive method to help prognosis making, condition severity evaluation and control the effectiveness of treatment of ocular local microcirculatory disturbances.

[Production of timolol containing calcium-phosphate nanoparticles and evaluation of their effect on intraocular pressure in experiment].

Methodology for production of calcium-phosphate nanoparticles is developed and its efficacy as a drug carrier system is estimated by example of timolol. Conditions for production of particles with optimal size and resistance are determined, methodology of loading of particles with timolol is developed. Physical parameters of particles (form, size, relief), kinetics of saturation with drug and its release are studied. Packaging of timolol into calcium phosphate nanoparticles was showed to enhance and prolong its hypotensive effect in experiment on healthy rabbits.

[Fibrinolysis components and angiogenesis regulation by example of burn-induced corneal neovascularization in rabbits].

Increased plasminogen level in tear fluid was found within 28 days and increased plasmin activity in 1-3 and 21 days after alkali burn of cornea, this is the time of cornel ulcers development. Increased plasminogen level and plasmin activity in cornea, conjunctiva and intraocular fluid was found in three days after trauma. Subconjunctival injections of angiostatin K1-4,5 (a product of plasminogen metabolism) during 3 weeks resulted in significant suppression of corneal neovascularization within 14 days and of active branching of the vessels in the following. The use of angiostatin reduced depth and area of corneal ulcers. Obtained data shows the promising potential of development of medications based on angiostatin K1-4,5 for suppression of corneal neovascularization and for treatment of diseases associated with corneal ulceration.

[Experimental rationale for local use of angiotensin-converting enzyme inhibitors for the treatment of ocular tissue ischemia on a model of postburn conjunctival ischemia].

The authors have evaluated the local renin-angiotensin system on a model of experimental postburn conjunctival ischemia from the tear activity of angiotensin-converting enzyme (ACE) and studied whether impaired microcirculation might be restored by locally applying the ACE inhibitor captopril. It has been found that in conjunctival ischemia, there is a considerable increase in the activity of ACE, the key enzyme of the renin-angiotensin system, the activity of which largely determines the microcirculation in eye tissues. Instillations of the ACE inhibitor to rabbits within 2 weeks after alkaline burn of the eye result in a reduction in ACE activity and an earlier recovery of microcirculation in the area of conjunctival ischemia. Instillations of the ACE inhibitor captopril in ocular burn facilitate the maintenance of the tear antioxidant potential at the high level, which also suggests that the ACE inhibitor has a positive effect on the course of reparative processes after ocular burn injury. The findings suggest that it is promising to locally use ACE inhibitors for the treatment of ischemic processes in the eye.

[Mental rationale for local use of angiotensin-converting enzyme in the treatment of inflammatory processes in the eye].

A rabbit model of deep alkaline-induced corneal burn was used to study the involvement of the local renin-angiotensin system of the eye in the development of an inflammatory process and wound healing. Corneal burn injury was shown to cause a significant increase in the activity of angiotensin-converting enzyme (ACE) in the tear and internal ocular tissue structures, promoting their microcirculatory disorders and inflammation development. The local use of ACE inhibitors as instillations substantially reduces an inflammatory reaction and the incidence of deep and extensive corneal ulcers. The study performed provides experimental rationale for the local use of ACE inhibitors for the treatment of inflammatory processes in the eye.

[Activity of angiotensin-converting enzyme in the blood and tear of patients with diabetic retinopathy].

There have recently been data on the important role of the renin-angiotensin system (RAS) in the pathogenesis of diabetes mellitus and its complications; however, the relationship of systemic and local RAS to the development of diabetic retinopathy (DR) remains little studied. This study determined the activity of angiotensin-converting enzyme (ACE), the key enzyme of RAS in the blood and tear of patients with DR. There was an increase in the blood activity of ACE and a decrease in its lacrimal activity as compared with their normal levels. A relationship was found between the activity of ACE in the blood and tear, on one hand, and the stage of DR, the type of diabetes mellitus, its severity and compensation, and the presence of nephropathy in a patient, on the other.