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Information about embryonic development of coronary endothelium is the main clue for the creation of new methods in tissue engineering for treatment of ischemic heart diseases. The purpose of the research was to describe human coronary vessels development on early stages of the prenatal ontogenesis. The first step in human coronary vessels development is the formation of endothelium de novo by transformation of some epicardial and, possibly, endocardial cells. The next step is the ingrowth of sinus venosus endothelium in subepicardium over ventricles and atria, which gives rise to the coronary vessels. Only after 7 days does the primitive coronary plexus of the heart communicate with aorta (third step). During this period, some subepicardial vessels invade myocardium and some intramyocardial vessels contact with the heart cavity. Such intercommunications could help in regulation of blood circulation in primitive coronary plexus before establishment of effective contacts between arterial and venous vessels—excess of blood could be discharged directly into the heart cavity. Additional population of CD34+ cells were revealed inside condensed mesenchyme of the conotruncus; it participates in the formation of vasa vasorum in the aorta. Epicardium and sinus venosus generate endothelium of coronary vessels by neovasculo- and angiogenesis, respectively. During a week after ingrowth of vessels from SV and before their ingrowth to the aorta, ventriculo-coronary communications could be found in the heart.

The applying of millimeter-wave electromagnetic emission (EHF-therapy) is an effective method for various age-related pathologies treatment, among other cardio-vascular diseases. During the EHF-emission of aging human endothelial cell cultures it was obtained changing of NO-synthase (eNOS), endothelin-1, angiotensin-2 and vasopressin expression dependence of irradiation exposition. These data have shown that EHF-emission has activated endothelium functional activity, which can play the important role to search for approaches to treatment of arterial hypertension and atherosclerosis.

Choroid plexus of human 8 wks old telencephalon embryo was studied using light and electron microscopy and immunocytochemistry. Precise description of epithelial cells and choroid plexus stroma ultrastructure is given as well as distribution of vimentine interstitial filaments in epithelial cells cytoplasm. The structure of choroid plexus blood vessels was studied. Smooth myocytes were not found in blood vessel wall. Vascular wall consists of single layer of endotheliocyte lacking basal membrane. At this stage of development endothelium was not fenestrated. Based on morphological data conclusions were made of fundamental condition of choroid plexus tissue elements.

Postcapillary venules with high endotheliocytes as paths of lymphocyte migration differentiate in corticomedullary zone of thymus in human 4-5 months old foetuses. Development of postcapillary venules from blood capillaries is closely associated with zonal differentiation of the organ substance and intensification of lymphocyte recirculation in the fetal immune system.

An attempt is made to summarize the main stages of the determination and specification of the heart in chicken, mouse, and rat embryos and to show what is currently known about the genes that participate in heart formation at early developmental stages in vertebrates.

Using quantitative methods (radioautography using thymidine label, DNA cytophotometry and mitotic index definition) proliferative properties of the vascular wall main cell differons (endothelium, smooth myocytes and fibroblasts) were investigated in 60 rats during postnatal and reparative morphogenesis. Most pronounced DNA synthesis was noted to occur in aortal endothelium in newborn animals and in fibroblasts of adventitia in 1 and 6 months and old aged (2.5 years) rats. In various vessel types of adult animals significant differences of label incorporation in fibroblasts of adventitia were not revealed whereas endothelial daily proliferation pool varies significantly showing minimal value (0.5%) in inferior caval vein and maximal (6%)-in capillaries. During the regenerative morphogenesis of aorta, caused by adventita cryodestruction proliferative activity elevation was noted in all the cell types, most reactive of them being smooth myocyte differon of the media.

Distribution of nitric oxide synthase in the forming cortex of human embryo brain was studied after the paraformaldehyde fixation by histochemical method of NADPH-diaphorase revealing. Since week 7 of the development in the prosencephalon up to week 12 the enzyme was located in the vessel endotheliocyte cytoplasm and presumably in the radial glia cell processes. During this period of embryogenesis no nerve cells containing nitric oxide synthase are present in the prosencephalon.

The development of the intraorgan vascular bed is brought about by means of a loop-like vascular growth which forms not only arteries and veins of all levels but that of microcirculation system as well. Embryonal angiogenesis is followed by a programmed death of the endothelium of all autochtone structures and some functioning microvessels of a closed circulation. This process is of importance in remodelling of vascular bed and formation of collateral circulation and anastomoses.

Smooth-muscle cell (SMC) myosin expression, SMC alpha-actin, h-caldesmon and calponin expression were studied in developing SMC of embryonic aorta as well as in adult human aorta and coronary arteries. It was found that ontogenesis is associated with SMC phenotypic modulations. In 8-23-week embryos SMC express SMC myosin and alpha-actin. In adult humans arterial SMC express all the markers studied. Normal subendothelium contains a heterogeneous SMC population. SMC heterogeneity is most marked in atherosclerotic plaques in the form of clusters of homogeneous cells different by expression of contractile system proteins. It is suggested that SMC heterogeneous population in atherosclerotic plaques may arise due to proliferation of phenotypically different precursors cells.

Transmission electron microscopy was used for studying the thoracic part of the aorta of 9 human fetuses of 20-28 weeks of development. In the medial tunic of the human fetus aorta there are smooth myocytes (SM) of the contractile and synthetic phenotypes. The latter are localized mainly in the inner part of the media. In the inner tunic there are also SM of the synthetic phenotype. With the help of processes they make contacts with endotheliocytes and processes of SM of the media. In the gaps between the subendothelial SM and endothelium there are particles of elastin which form the structure resembling an additional elastic membrane. It is reasonable to think that the migration of SM into the intima is a stage of normal development of the vessel associated with the adaptation to local hemodynamic conditions rather than an initial manifestation of atherosclerosis.

It was found by means of light and transmission electron microscopy that the arteriolar portion of the blood circulatory bed of functionally different organs is formed during intrauterine development as a result of structural transformations of cellular and noncellular components of the wall of afferent microvessels of the protocapillary bed.