A.D. Turashev, A.A. Fedorovich, E.G. Tischenko, A.N. Rogoza, A.V. Maksimenko

Normally, the surface of vascular endothelial covers a multicomponent system - endothelial glycocalyx - which, due to its complexity and location, involved in a number of functions that support the metabolism of the circulation. In pathological conditions there is a complete or partial loss of this structure, which leads to disintegration of the vascular wall and change its function. This situation could be a possible cause of the defeat of the microcirculation that can complicate the effects achieved by the standard therapy in the management of patients with cardiovascular abnormalities. An example of such multifactorial pathological processes appears the phenomenon of no-reflow, the resulting one-quarter of patients with acute myocardial infarction with ST-segment elevation on ECG. Glycosidase enzymes are involved in the catabolism of structural components of the endothelial glycocalyx - glycosaminoglycans. Due to this fact enzymes of this type are an effective tool for studying the function glycocalyx in normal and pathological conditions. The functioning of these enzymes occurs in a microenvironment of a saccharides (sugar of blood with low molecular weight and glycosaminoglycans and glycocalyx), which regulate their structure and specific activity, including the expense of the process of protein glycation. Under glycation covalent modification of the protein structure occurs with aldosaccharides (including glycosidases involved in the catabolism of glycocalyx. Therefore the study of behavior under the action on glycosidase enzymes with glycation agents of different nature and development of approaches to stabilize their enzymatic activity are reasonable as to study the functioning of the glycocalyx in a model of pathology and to develop therapeutic approaches for the treatment of diseases associated with disruption of the functioning of the vascular wall. Earlier in our studies have shown that covalent modification of one of these glycosidase - bovine testicular hyaluronidase - with chondroitin sulfate changed in the opposite way glycation nature of native and modified enzyme. Mono-and di-saccharides strongly inactivated native hyaluronidase than the modified chondroitin sulfate. Glycation with N-acetylgalactosamine gave the opposite picture: a modified hyaluronidase inactivated more native. Such properties transformed native and modified hyaluronidase enzyme into an informative research test in vivo for determination of the dominant species of glycation agents in the bloodstream and their origin: increased content of sugars in the blood in disorder of carbohydrate metabolism or growth products of glycocalyx degradation in disturbances of the microcirculation (ischemia / reperfusion, embolization, inflammation, etc.). In the model of postischemic perfusion of rat limbs we assessed recovery of microcirculation perfusion of hind limb to its initial level by using the laser Doppler flowmetry with the enzyme derivatives and their components. Native hyaluronidase accelerated recovery of the initial level of microcirculation, and the modified enzyme is expressed inhibited glycocalyx degradation products. Resulting from the administration of assayed derivatives with various schemes, the investigated data indicate the dominant presence of glycocalyx degradation products in the microcirculation after ischemic exposure, identified by the nature of the restoration of skin perfusion in the presence of modified hyaluronidase. These findings point to the direction of further work on the enzymatic regulation of microvascular glycocalyx state and development of new therapeutic approaches for the treatment of microcirculation complications in acute cardiovascular injuries.