Capillaries In Terminal Villi Research Articles

Histopathological Changes In Placentas Due To Pregnancy-Induced Hypertension And Gestational Diabetes Compared With Normal Term Placenta

Hypertension is the most commonly known problem of restoration during pregnancy, with up to 10% of pregnancies confused. Gestational diabetes mellitus is described as the occurrence or for the first time in pregnancy of a change in glucose levels to varying degrees. There are medical problems when diabetics and hypertension worsen pregnancy and affect maternal health. Objectives: Analysis of unexplained placenta changes in patients with concomitant hypertension and gestational diabetes caused by pregnancy. Materials and Methods: This study included forty placentas, twenty were collected from uncomplicated normotensive pregnant ladies, and the rest (20 placentas) were collected from ladies with concomitant gestational diabetes and pregnancy-induced hypertension. Histological sections were prepared using routine haemotoxyline and eosin staining. Results: The histomorphological study of placenta of patients with concomitant hypertension and diabetes mellitus showed a significant number of syncytial knots, stromal fibrosis, and the number of capillaries in terminal villi in Medium-sized diffusion areas of the vascular median cover. Conclusion: Placenta examination is very important for the diagnosis of various pathological conditions, mechanisms are still far from well understood, but there is a common consensus that the pathological level depends on the type of diabetes and hypertension during pregnancy. This study provides an opinion of previous studies with a great association placental changes in patients with concomitant pregnancy-induced hypertension and diabetes. The clinical appearance and the magnitude of placental pathological changes were strongly associated. There is a wide range of microscopical changes noted as increased the numbers of the syncytial ganglia, fibrosis and the number of capillaries in the peripheral appendages

Pericytes on placental capillaries in terminal villi preferentially cover endothelial junctions in regions furthest away from the trophoblast

IntroductionPericytes are a common feature in the placental microvasculature but their roles are not well understood. Pericytes may provide physical or endocrine support for endothelium and in some tissues mediate vasoconstriction. MethodsThis study uses serial block-face scanning electron microscopy (SBFSEM) to generate three-dimensional (3D) reconstructions of placental pericytes of the terminal villi and transmission electron microscopy (TEM) to study pericyte endothelial cell interactions. The proportion of endothelial cell junctions covered by pericytes was determined. ResultsThe detailed 3D models of placental pericytes show pericyte structure at a new level of detail. Placental pericytes have many fingers extending from the cell body which can span multiple capillary branches. The proportion of endothelial cell-cell junctions covered by pericytes was significantly higher than pericyte coverage of capillary endothelium as a whole (endothelium: 14%, junctions: 43%, p < 0.0001). However, the proportion of endothelial cell-cell junctions covered by pericytes in regions adjacent to trophoblast was reduced compared to regions >3 μm away from trophoblast (27% vs 62% respectively, p < 0.001). No junctional complexes were observed connecting pericytes and endothelial cells but there were regions of cell membrane with features suggestive of intercellular adhesions. DiscussionThese data suggest that the localisation of pericytes on the villous capillary is not random but organised in relation to both endothelial junctions and the location of adjacent trophoblast. This further suggests that pericyte coverage may favour capillary permeability in regions that are most important for exchange, but limit capillary permeability in other regions.

МОРФОМЕТРИЧЕСКАЯ ХАРАКТЕРИСТИКА ТЕРМИНАЛЬНЫХ ВОРСИН ПЛАЦЕНТЫ ПРИ НЕДОНОШЕННОСТИ

In this study, morphometric features of terminal villi in term and preterm placentas were compared. Placentas of 13 patients whose pregnancy ended in premature birth and placentas of 35 women with physiological pregnancy and delivery at term were studied. Morphometric assessment was made with Carl Zeiss Axio Imager microscope using an image analysis software package. The number of capillaries in terminal villi of preterm placentas was found to be decreased, while the vessels-to-syncytiotrophoblast distance was found to be increased. These result in a decreased gas exchange between maternal blood and placental tissue, hypoxia and can cause early termination of pregnancy. Mean values of cross-sectional area, vertical dimension and perimeter of terminal villi in preterm placentas are found to be greater than those in term placentas, which contributed to an increase in gas exchange area and can be regarded as a compensatory reaction at a tissue level.

Stereological analysis of terminal villi of the placentas of pregnant woman with sideropenic anemia.

Iron deficiency, causing maternal sideropenic anemia, is one of the most frequent nutritive disorder that develops during the pregnancy. We collected 30 placentas from anemic mothers and 30 placentas from mothers belonging to the control group. Terminal villi (magnification 10x) and terminal villi capillaries (magnification 40x) were stereologically analyzed and numerically determined.In the placentas from anemic mothers we noted the values a) terminal villi: volume density 0,43 mm0, surface density 24.13 mm-1, total volume 185.57 cm3 and total surface 10.27 m2; b) capillaries of terminal villi: volume density 0.53 mm0 and total volume 224.18 cm3. In the placentas from mothers belonging to the control group we observed the following values a) terminal villi: volume density 0.44 mm0, surface density 22.27 mm-1, total volume 200.17 cm3 and total surface 10.15 m2; b) capillaries of terminal villi: volume density 0.42 mm0 and total volume 197.00 cm3. Compared with the control group anemic mothers' placentas have a significant higher values of surface density of terminal villi (p&lt;0.05), volume density (p &lt;0.01) and absolute volume (p&lt;0.0001) of terminal villi capillaries, and significant lower values of absolute volume of terminal villi (p&lt;0.05).In anemic mothers' placentas, the total volume of terminal villi changes disproportionately to the total surface of terminal villi with statistically significant increase of terminal villi capillaries compared with control group.

Spatial Arrangement of the Microvascular Bed in the Human Placenta

Spatial Arrangement of the Microvascular Bed in the Human Placenta The knowledge of the spatial arrangement of microvascular bed is necessary for understanding the organ function. Various models and functional interpretations of the spatial organization of placental microvascular bed were created in the past decades however their plausibility was highly influenced by technical level of used methods. In this paper, methods and results of those studies are summarized and discussed. As the placenta in utero is hardly accessible for examination, the data regarding spatial arrangement of microvascular bed were obtained from ex vivo studies after termination of pregnancy. Imaging methods, i.e. X-ray angiography, X-ray microcomputed tomography and nowadays also MRI yielded information mainly on the spatial distribution and quantitative parameters of placental arterial system. The combination of SEM and corrosion casts demonstrated that capillaries of terminal villi branch from arterioles of mature intermediate villi, some capillary segments interconnect the capillary bed of neighboring terminal villi, and venules are arranged parallel with arterioles of mature terminal villi.

Quantitative Research of Capillaries in Terminal Villi of Mature Placentae

Advanced maternal age is known to be a risk factor for placental dysfunctions. The most common obstetric complications among older women would be considered as follows: gestational diabetes; pre-eclampsia; placenta praevia; preterm premature rupture of membranes and the risk of preterm delivery. The aims of research were to determine the impact of maternal age on the structure of terminal villi. The study was conducted on 60 human placentae of term pregnancy divided into two groups: the control group (30 placentae in pregnant women of age between 20 and 34) and the experimental group (30 placentae in pregnant women of 35 years of age and older). Stereological methods were applied to determine the volume density, surface density, total volume and total capillary surface area in terminal villi of placenta. The mean value of volume density of capillaries in terminal villi of placentae in older pregnant women is: Vvkks = (0,376 +/- 0,033) mm(0), and the mean value of total volume is: Vkks = (157,047 +/- 25,022) cm(3). The mean value of surface density is: Svkks = (64,783 +/- 2,543) mm(-1), and the mean value of total surface area is: Skks = (29,959 +/- 7,873) m(2). Volume density of capillaries in terminal villi of placentae is significantly lower in older pregnant women (p<0.001) in comparison to the younger pregnant women. The total volume, surface density and total capillary surface area in terminal villi of placentae are also significantly lower in older pregnant women (p<0.005) in comparison to the younger pregnant women. Statistically significant lower values of volume density, total volume, surface density and total capillary surface area indicate that there is a decreased metabolic transfer between mother and foetus.

Spatial arrangement of fetal placental capillaries in terminal villi: a study using confocal microscopy.

The spatial arrangement of capillaries was studied in terminal villi of placentas at term by using confocal microscopy and methods for different types of 3-D reconstructions. Fixed specimens embedded in paraffin or glycol methacrylate resin were cut and stained with eosin. Digitized images of serial optical sections (approximately 0.5 microm) of individual terminal villi lying completely inside physical sections (100 microm) were captured by confocal laser scanning microscopy and analyzed. Topological reconstruction of the capillary bed and measurements of its Euler number, surface and volume rendering and wire-frame visualization were performed. Our findings showed that villous capillaries are arranged either in a single loop or in a more or less complicated anastomosing system. The results suggest that the combination of confocal microscope capture, methods for 3-D rendering and characterization of topological features reveals valuable information about spatial relationships of tissues in placental villi and the arrangement of the villous microcirculation, e.g. about the branching pattern of capillaries.

Scanning electron microscopy of primate chorionic villi following ultrasonic microdissection

Villi from human, macaque and baboon placentae were subjected to ultrasonication after prolonged osmication, and examined by scanning electron microscopy. The technique was often successful in removing the overlying trophoblast and revealing expanses of the trophoblastic basal lamina, a conclusion corroborated by transmission electron microscopy. These preparations bore a remarkable similarity in appearance to microvascular cast preparations of the fetal vasculature. Relatively straight parallel tubules appeared to correspond in position to the location of fetal vessels in intermediate villi, whereas portions of the basal laminae of terminal villi were in the form of convoluted, branched cylinders similar to SEM images of fetal capillaries of terminal villi. The basal lamina did not have evidence of pores as has been described in some basal laminae.