The thesis is devoted to the important and actual medical and biological problem – the development and formation of human heart vessels in the prenatal period of ontogenesis. The study of patterns of the formation and development of the human heart, the development of the coronary heart system in the embryonic and fetal life periods is an important problem of age morphology. Considering that in the prenatal period of human development the main morphogenetic events and restructuring of the structural components of the heart occur, as well as the congenital malformations are formed, the data obtained in this age period has special importance in the development of holistic definitive organ. Changes that occur in the atria and ventricles of the heart, in the vascular system continue to be the object of research of modern domestic and foreign scientific forums of various levels, scientific labora¬tories, researchers of cardiogenesis. The development of modern diagnostic comple¬xes that are used in screening studies of intrauterine development of the embryo and fetus requires new morphological studies of prenatal changes in organs and systems.
The research work was carried out on a sufficient anatomical material (embryonic and human fetuses from the 5th to the 24th week of the prenatal period of development, fragments of the hearts of human fetuses without congenital pathology, obtained from healthy mothers were confirmed by medical documentation when they entered the hospital). Using modern morphological methods, namely, anatomical (macro– and micropreparation for visualization and description of the vessels of the heart, the method of injection of the vascular bed with dental plastics for the study of angioarchitectonics and regional features of the hemo– and lymphocirculatory channel of the fetal heart); histological (micropreparations staining with hematoxylin and eosin to establish the relationship between the vascular and muscular components in the walls of the heart); scanning electron microscopy (for the study of the features of the relief of the vessels of the heart); immunohistochemical study (to determine the degree of expression of endothelial markers CD34 and CD31, the Ki – 67 proliferation marker and a–SMA angiogenesis markers, Prox1), 121 hearts of embryos and human fetuses were treated. To confirm the reliability of the quantitative data, morphometric and biostatistical research methods were used in the work.
To determine patterns of development, the formation and structure of various units of heart bloodstream during prenatal human ontogenesis was studied ways of forming vascular human heart units in steps of cardiogenesis in the embryonic period, especially morphogenesis of arterial system of the heart in a prolific period of human development, designed morphogenesis venous system of the heart in a fruitful period of human development. The peculiarities of the formation of the lymphatic system of the heart in a seminal period of human development and the dynamics and regional features of the distribution of various vascular segments in the human heart. The results of the obtained studies confirmed that the main source of development of cardiovascular elements of the proepicardial cells is transformed by the epithelial – mesenchymal transformations into endothelial cells, which, with further formation and specialization of the vascular links form a network of heart vessels.
These processes occur in parallel with a number of other shaping stages of cardiogenesis. The use of new chain specific vascular immunohistochemical markers made it possible to evaluate the expression and specificity of cells in the prenatal period of ontogenesis in the human heart.
After the appearance of the endothelium and the formation of new vessels the process of angiogenesis began, in our understanding, the stages of differentiation of the walls of the formed vessels, i.e., separation to the arterial, venous and lymphatic segments. In the embryonic period, when active proliferative processes occur in the formed 4–chamber heart, the epithelial–mesenchymal transformation proceeds at a rapid pace, we evaluated the chronological and topological features of endothelial
Dimensional analysis of corrosive preparations of microvasculature of the heart in fetuses at 16-24 weeks showed quantitative-qualitative changes in orientation, shape and sequence of vascular segments. For the first time in the study of corrosion specimens’ scans of the vascular bed of the myocardium of the atria and ventricles of human fetal hearts aged from 16 to 24 weeks it was determined that the microvasculature is represented by all components of the microvascular unit, where arterioles and venules of fetuses at 16-19 weeks do not yet reach ordered mutual orientation, whereas at 22-24 weeks arterioles and capillaries are predominantly in parallel and form a group of vessels located in accordance with direction of the muscle fibers and the venous links
