Introduction. Placental dysfunction is underlying cause in most of the intrauterine growth restriction and the pregnancy complications where the fetus does not achieve its genetically determined potential for growth. The critical process for the development of the placenta is angiogenesis. CD31 is an important endothelial adhesion protein that enables angiogenesis. The study aimed to analyze the CD31 expression and vascular parameters in normal placentas and IUGR placentas. Methods. Thirty placental samples, fifteen IUGR placentas, and fifteen term normal placental samples were analyzed. The hematoxylin-eosin method and immunohistochemical method with anti CD31 antibody were used for the staining of the tissue sections. The analyzed vascular parameters were: capillary number density (CND), capillary area density (CAD), and capillary surface density (CSD). Results. Between normal placentas and IUGR placentas there was no determined difference in CD31 expression. Positive intensive staining of CD31 was found in the endothelium of all blood vessels and no staining was observed in cytotrophoblast and syncytiotrophoblast cells. In IUGR placentas, CND of 2.55 capillary/1000 µm2 villous area was significantly decreased compared to normal placentas of 3.49 capillary/1000 µm2 villous area. CAD in IUGR placentas of 30.49 % was significantly decreased compared to normal placentas of 52.80 % villous area. CSD in IUGR placentas (92.81 µm/1000µm2) was significantly reduced compared to CSD in normal placentas (145.51 µm/1000µm2). Conclusion. The localization and intensity of CD31 expression were not different between the IUGR and normal placentas. Histological vascular parameters of placental villi are decreased in the IUGR placenta. In case of intrauterine growth restriction, there is a reduced vascularization of the terminal villi of the placenta.

Background: The process of prenatal hematopoiesis occurs in various anatomical locations, including the placenta. The placenta is not merely a temporary hematopoietic reservoir, but it is one of the key sites for the synthesis of hematopoietic stem cells (HSCs). This study aimed to investigate the presence, distribution, and immunoprofiles of HSCs in the human placenta during different gestational periods. Materials and Methods: Placental samples of different gestational ages (first, second, and third trimesters) were analyzed using classical hematoxylin and eosin staining and immunohistochemical staining for CD34, CD117, and CD41 markers, with HSC quantification through numerical areal density (N_A). Results: Highly immunoreactive CD34 HSCs were present in placentas throughout gestation, while highly immunoreactive CD117 and CD41 HSCs were observed during the first two trimesters. In the first trimester, HSCs were found within the lumen of blood vessels and as individual cells in the mesenchyme of chorionic villi. With advancing gestation, the number of HSCs in the mesenchyme of chorionic villi increased. Conclusions: Immunoreactive CD34, CD117, and CD41 cells are present in significant proportions in various parts of the placenta throughout gestation, indicating that the placenta provides a substantial proportion of HSCs for hematopoiesis.

Background: The process of prenatal hematopoiesis occurs in various anatomical locations, including the placenta. The placenta is not merely a temporary hematopoietic reservoir, but it is one of the key sites for synthesis of hematopoietic stem cells (HSCs). This study aimed to investigate the presence, distribution, and immunoprofiles of HSCs in the human placenta during different gestational periods. Materials and Methods: Placental samples of different gestational ages (first, second, and third trimesters) were analyzed using classical hematoxylin and eosin staining and immunohistochemical staining for CD34, CD117, and CD41 markers, with HSCs quantification through numerical areal density (NA). Results: Highly immunoreactive CD34 HSCs were present in placentas throughout gestation, while highly immunoreactive CD117 and CD41 HSCs were observed during the first two trimesters. In the first trimester, HSCs were found within the lumen of blood vessels and as individual cells in the mesenchyme of chorionic villi. With advancing gestation, the number of HSCs in the mesenchyme of chorionic villi increased. Conclusion: Immunoreactive CD34, CD117, and CD41 cells are present in significant proportions in various parts of the placenta throughout gestation, indicating that the placenta provides a substantial proportion of HSCs for hematopoiesis.

The tissue sample analysis based on the visualization of the entire tissue sample represents an important methodology in clinical diagnostics, research, and education. This process that enables visualization of the entire tissue sample is named whole slide imaging. For clinical purposes, professional and very expensive scanners are used for tissue sample digitization and the creation of whole slide images. In education, it is possible to use whole slide images that do not necessarily follow strict medical standards and regulations. Therefore, the important research task is to propose a methodology for the manual creation of whole slide images and its adequate use in medical education. In this paper, the use of manually created whole slide images in histology classes education was analyzed. In the experimental part of this research, the methodology of manual creation and usage of whole slide images (WSI) in histology education is presented in more detail. The subjective assessment of the user's satisfaction with WSI usage in education was also performed. It was shown that the whole slide images were evaluated very positively in the histological analysis and education process. Using WSI can significantly improve histology teaching, especially when distance education principles are implemented. Therefore, in crises like the pandemic situation COVID-19 WSI usage becomes a very important educational tool for teaching microscope-related topics. The results of this research showed that the use of whole slide images in histology classes is in line with the process of digital transformation in education.

Background/Aim: With an increase in cardiac output, blood pressure values in pregnancy increase. The aim of the study was to examine the effect of prenatal exercises on the circulatory parameters and the correlation between blood pressure and nailfold capillary parameters in healthy pregnant women. Methods: The blood pressure shape and length of nailfold capillary were assessed in 35 non-exercising pregnant women and 35 pregnant women who exercised, at the beginning of the study (between 20 and 32 gestational week) and the end of the study (28 - 40 gestational week). Results: The elevation in blood pressure was significantly lower in pregnant women who exercised in relation to non-exercising pregnant women. After eight weeks, the length of the capillary loops was increased by 30 µm and the number of pregnant women with pronounced shape changes of capillary loops increased, with no difference between the groups. Non-exercisers had a correlation between the change in diastolic pressure and the increase in capillary length (r = 0.53, p = 0.001). In the experimental group, the correlation between the change in blood pressure and the increase in the length of capillary loops was not determined. Conclusion: Prenatal physical activity had a beneficial impact on the circulation of pregnant women. In pregnant women in the third trimester, after eight weeks of follow-up, the length of the nailfold capillary loops and the presence of pronounced shape changes of capillary loops were increased, without difference between exercisers and non-exercisers. In non-exercising pregnant women, the capillary length was increased with the elevation of diastolic blood pressure, while the correlation was not found in pregnant women who exercised.

Introduction: The development of tissues in certain organs takes place simultaneously with the development of blood vessels. The placenta is an organ whose development provides a unique model for examining and understanding the process of organogenesis. The vascular endothelial growth factor (VEGF) is one of the first identified angiogenic factors and one of the most important regulators of normal and pathological angiogenesis. The aim of the study was to determine the localization and intensity of VEGF expression in the normal term placenta. Methods: The study analyzed ten normal term placental samples of healthy pregnant women (from the 38th to the 40th week of gestation). Placental tissue sections were stained with the standard hematoxylin-eosin method (HE) and with the immunohistochemical method for VEGF. Results: The small number of cells of the amniotic epithelium and trophoblast had positive VEGF expression of low intensity. Positive VEGF expression of moderate intensity was present in a small number of cells of the chorionic plate stroma, villi stroma, and basal plate. Positive VEGF expression of moderate intensity was present in more than 50% of endothelial cells (3+) of all placental blood vessels. Conclusions: Positive VEGF expression was present in the amniotic epithelium, mesenchymal cells of the chorionic plate, trophoblast, stroma cells of the villi, endothelial cells of the placental blood vessels, and the cells of the basal decidua. In the placenta, the most intensive immunoreactivity for VEGF was present in the endothelium of the placental blood vessels. Positive VEGF expression in the normal placenta indicates a significant role of VEGF in the development of the placenta.