Mitral valve prolapse (MVP) and associated hemodynamic disturbances are the most frequent clinical manifestation of the syndrome of undifferentiated connective tissue dysplasia. Among the reasons for its development may be deficient in magnesium ions as a cofactor of kinases involved in the phosphorylation of glucose. Activity of transglutaminases and lysyl oxidase, involved in the formation of cross-linking of collagen and elastin, decreases with magnesium deficiency. As a result, the mechanical strength of connective tissue fibers decreases. Metabolic disorders leads to disruption of the formation of fibrous and interstitial cardiac skeleton. Morphological changes in the status of the loose fibrous connective tissue (LVCT) from skin are comparable with the same changes in LVCT in the interstitial tissue of myocardium. The bioavailable material (skin biopsy) can be use for study of morphological and functional characteristics of LVCT, and these data correspond with the morphological and functional characteristics of LFCT from myocardium.
Material and methods: The study included 59 patients with MVP with phenotypic features of undifferentiated connective tissue dysplasia. All participants underwent a standard echocardiographic evaluation of transmitral flow at baseline and after 8 weeks after administration of magnesium orotate (MO). To assess the dynamics of morphological and functional changes in the samples were used LFCT skin biopsies which were subjected to a complex morphological analysis (light, scanning electron microscopy (Quanta 200 3D, FEI Company, USA ), original hystochemistry method for the detection and evaluation of the basic substance in LFCT and energy dispersive X-ray analysis for the chemical elements detection (EDAX, USA). Morphological changes of RVST in patients with MVP after the application of MO were connected with significant increasing of the volume of the amorphous matrix, ordering of interposition of fibers and the appearance of "bridges, cross-linkages" between them, as well as an increase in proteoglycans content. These changes indicate on reorganization of architectonic of LFCT and improvement its metabolic status. Content of potassium and magnesium in LVCT were increased significantly, after patients had received MO. Applying MO in patients with MVP improves parameters of intracardiac hemodynamic and diastolic function in the absence of changes in its inotropic function. These functional changes directly related to improving the diffusion capacity of the connective tissue, reorganizing its architectonics, improving its elasticity and stretchability.