Kotsiuruba Av

Bio: Kotsiuruba Av is an academic researcher from National Academy of Sciences of Ukraine. The author has contributed to research in topics: Arginase & Ecdysterone. The author has an hindex of 5, co-authored 31 publications receiving 68 citations.

[The inhibition of oxidative and nitrosative stresses by ecdysterone as the mechanisms of its cardio- and vasoprotective action in experimental diabetes type I].

Abstract: Streptozotocine (STZ) administration (5 mg/100 g) up regulates oxidative (lipid peroxidation as a marker) and nitrosative (protein nitrosilation as a marker) stresses as well as ROS (O(2-), H2O2, OH) generation in heart and aorta in rats after 60 days of STZ action. The level of oxydative stress was higher in aorta. Xanthine oxidase (XO) activation (uric acid as marker), but not lipoxygenase (LTC4 as marker) or cyclooxygenase (TxB2 as marker) are the main oxydases that generate O(2-) as calculated by correlation analysis. STZ administration led to sphingosine pools up regulation in heart and aorta, but pools of polyamines in this organ was down regulated. C27-phytosteroid hormone ecdysterone (100 ng/100 g, per os, 60 days) mimics the action of its structural analog C27-steroid hormone calcitriol (1alpha,25-dihydroxyvitamin D,) and protects rise of ROS generation (by XO inhibition), lipid peroxidation, protein nitrosilation, polyamine degradation in heart and aorta of rats after STZ administration. The new mechanism of iNOS activation, prostaglandine and tetrahydrobiopterin synthesis stimulation by ecdysterone has been proposed. It was due to stimulating enzymatic degradation of sphingosine-1-phosphate as effective regulator of iNOS, COX and GTP-cyclohydrolase in cardio-vascular system: sphingomyelin > ceramide > sphingosine > S-I-P > phosphoethanolamine > ethanolamine.

[Disorders of endothelium-dependent vascular reactions and of the arginase and NO-synthase pathways of L-arginine metabolism in arterial hypertension].

Abstract: In normotensive rats (NTR) and spontaneously hypertensive rats (SHR) with high (subgroup 1) and low (subgroup 2) level of the systemic arterial pressure (SAP) we studied an activity of arginase and nitric oxide synthase (NOS) in different tissues, and the content of their metabolites: urea and nitrit anion (NO2-). In isolated preparations of a thoracic aorta we recorded endothelium-dependent (ED) dilator reactions on acetylcholine (Ach). It has been found that in heart, aorta, plasma and erythrocytes of rats (subgroup 2) both the activity of arginase and content of urea increase remarkably. In heart, the activity of arginase reaches 27.96 +/- 5.92 nmol.min-1.mg-1 of protein, in aorta 4.74 +/- 0.99 nmol.min-1.mg-1 of protein (as compared with NTR 1.32 +/- 0.12 nmol.min-1.mg-1 of protein and 1.12 +/- 0.07 nmol.min-1.mg-1 of protein, accordingly). Content of urea in heart reaches 679.5 +/- 121.19 nmol.mg-1 of protein, in aorta 350.6 +/- 63.6 nmol.mg-1 of protein (in NTR it was 36.8 +/- 5.3 nmol.mg-1 of protein and 43.02 +/- +/- 9.55 nmol.min-1.mg-1 of protein, accordingly). It was followed with a decrease in the NOS activity and heterogeneous changes in NO2- content in the tissues under exploration. For example, the activity of NOS in heart and aorta decreased to 0.018 +/- 0.005 nmol.min-1.mg-1 of protein, in aorta 0.183 +/- 0.037 nmol.min-1.mg-1 of protein, accordingly, as compared to 0.093 +/- 0.014 nmol.min-1.mg-1 of protein and 0.41 +/- 0.07 nmol.min-1.mg-1 of protein in NTR. Content of NO2- in aorta decreased by 0.79 +/- 0.06 nmol.mg-1 of protein, but in heart it increased to 0.63 +/- +/- 0.13 nmol.mg-1 of protein, (in NTR it was 2.15 +/- 0.18 nmol.mg-1 of protein and 0264 +/- 0.04 nmol.min-1.mg-1 of protein, accordingly). In rats, subgroup 2, ED dilator responses of the smooth muscle (SM) of the thoracic aorta were inhibited by Ach (10(-6) mol). Their amplitude reduced by almost twice, and a latency for their response became 4 times as much. All the changes in the biochemical parametres in heart, aorta, plasma and erythrocytes, and changes in contractile activity of vascular SM proved to be also characteristic for rats in subgroup 1, but they were less expressed quantitatively. Thus, for the first time we have studied an activity of two alternative pathways for the metabolism of L-arginine on the model of arterial hypertension. The data obtained evidence that at hypertension non-oxidative (arginase) pathway of L-arginine metabolism is activated, while the oxidative pathway (NOS) is inhibited. Changes in the balance between them are followed with an essential inhibition of ED vasodilator responses. All this give us the prove to think of the origin for the arterial pressure increase to be both genetically and quantitatively determined damages in the biochemical homeostasis and dependent on it endothelial regulation of vascular tone.

Mitochondrial permeability transition pore opening inhibition by ecdysterone in heart mitochondria of aging rats

Abstract: Nitric oxide reacts rapidly with superoxide to produce the potent oxidant peroxynitrite. In vivo mitochondria produce superoxide as well as NO. In heart mitochondria of aging rats the amount of NO and O2(-) are increased thus the levels of peroxynitrite produced may be increased too, in this reason mitochondria may be a major site of peroxynitrite formation. Oxidative stress induces cyclosporine A-sensitive mitochondrial efflux of calcium and proapoptotic factors through MPTP (mitochondrial permeability transition pore) opening in heart mitochondria which may contribute to tissue damage and mitochondrial dysfunction in aging rats. We tested the levels of NO and superoxide generation in mitochondria simultaneously with cyclosporine A-sensitive MPTP opening by Ca2+ and phenylarsine oxide (PAO) to determine whether downregulation of both NO and O2(-) generation in heart mitochondria by potent steroid antioxidant and free radical scavenger ecdysterone may protect heart mitochondria of aging rats again tissue damage. C27-phytosteroid hormone ecdysterone (10 mkg/100g, per os, 2 weeks) mimics action of its structural analog C27- steroid hormone calcitriol (1alpha,25-dihydroxyvitamin D3) and exert its cardio protection in aging heart mitochondria by inhibition of MPTP opening with effectivity of action of hormone melatonine (150 mkg/100g, 2 weeks [ V.F. Sagach et al. Fyziol. J (Ukr), 2006, 52(2), 3-15]). MPTP inhibition is dependent on paradoxycally high activation by ecdusterone of oxidative degradation of L-arginine by mtcNOS in mitochondria, by downregulation of superoxide generation and L-arginine degradation by arginase II and NO generation by mtiNOS in de novo and by NADP-dependent mtNR (nitrate reductase) in salvage pathways. These results suggest that MPTP opening may be directly influenced by ecdysterone signaling in mitochondria. The signaling pathway by which ecdysterone may coregulate the O2(-) and NO generation in heart mitochondria of aging rats may involve an outer mitochondrial membrane estrogen receptor coupled to mitochondrial PI3K/Akt/PKB activation results in superactivation and constitutive NO synthesis by mtcNOS.

[NO-dependent mechanisms of ecdysterone protective action on the heart and vessels in streptozotocin-induced diabetes mellitus in rats].

Abstract: Ecdysterone (100 ng/100 g) chronic oral administration (2 months after STZ (5 mg/100 g) administration) normalized plasma glucose levels in rats This potent hypoglycemic effect of ecdysterone depend on inhibition of non-constitutive NO synthesis by Ca(2+)-independent iNOS and NADP-dependent nitrate reductase as well as inhibition of L-arginine degradation by arginase result in up-regulation of Ca(2+)-dependent constitutive NO synthesis by eNOS or mithochondrial nNOS in heart and aorta of rats

[Effects of uncoupling proteins on nitric oxide synthesis and oxidative stress development in ishemia-reperfusion of old rat hearts].

Abstract: Genipin is aglycone of geniposide, one of the active compounds of Gardenia gasminoides Ellis The gardenia fruit extract has been used in traditional Chinese medicine to relieve the symptoms of type 2 diabetes that is accompanied with extensive oxidative stress and endothelial dysfunction of NO production Besides, genipin was shown to inhibit UCP-depended proton leak through the inner mitochondrial membrane that leads to increased membrane potential and ATP production We studied the effects of genipin at ischemia/reperfusion-induced oxidative stress and activity of NOS isozymes using Langendorfperfused old rat heart model Ischemia/reperfusion is well-known oxidative agent, and showed significant increasing of superoxide radical, hydrogen peroxide and hydroxyl radical Genipin application in doze 10-5 mol/L for 15 min before prolonged ischemia exerted powerful antiradical and antilipoperoxidative effects Heart ischemia/reperfusion was supported with peroxynitrite generation and nitrozative stress We demonstrated the inhibitory property of genipin on INOS expression that possibly occurs via protein kinase A inhibition and stabilization of I-kappaB-NF-kappaB complex Genipin stimulated cNOS activity seemingly activating PI3K/Akt signaling pathway Although, post-ischemic recovery ofcardiodynamic parameters of old rat hearts were depressed due to "switching off" the NO production by inducible NOS which is important in early period of reperfusion Thus, we conclude that genipin is powerfull antioxidant and posses insulin-like activity due to its property of managing the NO production at intracellular signal transduction cascade level

Endothelial dysfunction in diabetes mellitus.

Abstract: Diabetes mellitus is associated with an increased risk of cardiovascular disease, even in the presence of intensive glycemic control. Substantial clinical and experimental evidence suggest that both diabetes and insulin resistance cause a combination of endothelial dysfunctions, which may diminish the anti-atherogenic role of the vascular endothelium. Both insulin resistance and endothelial dysfunction appear to precede the development of overt hyperglycemia in patients with type 2 diabetes. Therefore, in patients with diabetes or insulin resistance, endothelial dysfunction may be a critical early target for preventing atherosclerosis and cardiovascular disease. Microalbuminuria is now considered to be an atherosclerotic risk factor and predicts future cardiovascular disease risk in diabetic patients, in elderly patients, as well as in the general population. It has been implicated as an independent risk factor for cardiovascular disease and premature cardiovascular mortality for patients with type 1 and type 2 diabetes mellitus, as well as for patients with essential hypertension. A complete biochemical understanding of the mechanisms by which hyperglycemia causes vascular functional and structural changes associated with the diabetic milieu still eludes us. In recent years, the numerous biochemical and metabolic pathways postulated to have a causal role in the pathogenesis of diabetic vascular disease have been distilled into several unifying hypotheses. The role of chronic hyperglycemia in the development of diabetic microvascular complications and in neuropathy has been clearly established. However, the biochemical or cellular links between elevated blood glucose levels, and the vascular lesions remain incompletely understood. A number of trials have demonstrated that statins therapy as well as angiotensin converting enzyme inhibitors is associated with improvements in endothelial function in diabetes. Although antioxidants provide short-term improvement of endothelial function in humans, all studies of the effectiveness of preventive antioxidant therapy have been disappointing. Control of hyperglycemia thus remains the best way to improve endothelial function and to prevent atherosclerosis and other cardiovascular complications of diabetes. In the present review we provide the up to date details on this subject.

Multiple-motor based transport and its regulation by Tau

Abstract: Motor-based intracellular transport and its regulation are crucial to the functioning of a cell. Disruption of transport is linked to Alzheimer's and other neurodegenerative diseases. However, many fundamental aspects of transport are poorly understood. An important issue is how cells achieve and regulate efficient long-distance transport. Mounting evidence suggests that many in vivo cargoes are transported along microtubules by more than one motor, but we do not know how multiple motors work together or can be regulated. Here we first show that multiple kinesin motors, working in conjunction, can achieve very long distance transport and apply significantly larger forces without the need of additional factors. We then demonstrate in vitro that the important microtubule-associated protein, tau, regulates the number of engaged kinesin motors per cargo via its local concentration on microtubules. This function of tau provides a previously unappreciated mechanism to regulate transport. By reducing motor reattachment rates, tau affects cargo travel distance, motive force, and cargo dispersal. We also show that different isoforms of tau, at concentrations similar to those in cells, have dramatically different potency. These results provide a well defined mechanism for how altered tau isoform levels could impair transport and thereby lead to neurodegeneration without the need of any other pathway.

Antidiabetic Potential of Medicinal Plants and Their Active Components.

Abstract: Diabetes mellitus is one of the major health problems in the world, the incidence and associated mortality are increasing. Inadequate regulation of the blood sugar imposes serious consequences for health. Conventional antidiabetic drugs are effective, however, also with unavoidable side effects. On the other hand, medicinal plants may act as an alternative source of antidiabetic agents. Examples of medicinal plants with antidiabetic potential are described, with focuses on preclinical and clinical studies. The beneficial potential of each plant matrix is given by the combined and concerted action of their profile of biologically active compounds.

Upregulation of Vascular Arginase in Hypertension Decreases Nitric Oxide–Mediated Dilation of Coronary Arterioles

Abstract: One characteristic of hypertension is a decreased endothelium-dependent nitric oxide (NO)-mediated vasodilation; however, the underlying mechanism is complex. In endothelial cells (ECs), L-arginine is the substrate for both NO synthase (NOS) and arginase. Because arginase has recently been shown to modulate NO-mediated dilation of coronary arterioles by reducing l-arginine availability, we hypothesized that upregulation of vascular arginase in hypertension contributes to decreased NO-mediated vasodilation. To test this hypothesis, hypertension (mean arterial blood pressure >150 mm Hg) was maintained for 8 weeks in pigs by aortic coarctation. Coronary arterioles from normotensive (NT) and hypertensive (HT) pigs were isolated and pressurized for in vitro study. NT vessels dilated dose-dependently to adenosine (partially mediated by endothelial release of NO) and sodium nitroprusside (endothelium-independent vasodilator). Conversely, HT vessels exhibited reduced dilation to adenosine but dilated normally to sodium nitroprusside. Adenosine-stimulated NO release was increased approximately 3-fold in NT vessels but was reduced in HT vessels. Moreover, arginase activity was 2-fold higher in HT vessels. Inhibition of arginase activity by N(omega)-hydroxy-nor-l-arginine or incubation with l-arginine partially restored NO release and dilation to adenosine in HT vessels. Immunohistochemistry showed that arginase expression was increased but NOS expression was decreased in arteriolar ECs of HT vessels. These results suggest that NO-mediated dilation of coronary arterioles is inhibited in hypertension by an increase in arginase activity in EC, which limits l-arginine availability to NOS for NO production. The inability of arginase blockade or l-arginine supplementation to completely restore vasodilation may be related to downregulation of endothelial NOS expression.

Practical uses for ecdysteroids in mammals including humans: an update

Abstract: Ecdysteroids are widely used as inducers for gene-switch systems based on insect ecdysteroid receptors and genes of interest placed under the control of ecdysteroid-response elements. We review here these systems, which are currently mainly used in vitro with cultured cells in order to analyse the role of a wide array of genes, but which are expected to represent the basis for future gene therapy strategies. Such developments raise several questions, which are addressed in detail. First, the metabolic fate of ecdysteroids in mammals, including humans, is only poorly known, and the rapid catabolism of ecdysteroids may impede their use as in vivo inducers. A second set of questions arose in fact much earlier with the pioneering "heterophylic" studies of Burdette in the early sixties on the pharmacological effects of ecdysteroids on mammals. These and subsequent studies showed a wide range of effects, most of them being beneficial for the organism (e.g. hypoglycaemic, hypocholesterolaemic, anabolic). These effects are reviewed and critically analysed, and some hypotheses are proposed to explain the putative mechanisms involved. All of these pharmacological effects have led to the development of a wide array of ecdysteroid-containing preparations, which are primarily used for their anabolic and/or "adaptogenic" properties on humans (or horses or dogs). In the same way, increasing numbers of patents have been deposited concerning various beneficial effects of ecdysteroids in many medical or cosmetic domains, which make ecdysteroids very attractive candidates for several practical uses. It may be questioned whether all these pharmacological actions are compatible with the development of ecdysteroid-inducible gene switches for gene therapy, and also if ecdysteroids should be classified among doping substances.