Villi Vessels Research Articles

Fetal Vascular Ectasia Can be an Artifact of Placental Fixation.

Placentas from outlying hospitals are formalin-fixed en route to our laboratory. We identified that chorionic, stem villus, and umbilical vessels in these fixed placentas are ectatic with greater frequency than in our in-house fresh placentas. We searched our LIS for third trimester placentas using keywords "ectasia" or "ectatic" over a 12-month period. We fixed incoming in-house placentas over a 2-week period for 24-72hours and tabulated the presence or absence of vascular ectasia as defined by Parast et al, 2008. The LIS search identified 61% of placental cases from outlying hospitals that had ectatic vessels vs 3% of in-house placentas (P < .001). Of 38 placentas fixed in a 2-week period, 45% had ectatic chorionic or stem villus vessels and 21% had umbilical vessel ectasia. In comparison, in the 2 subsequent weeks, 3.8% (P < .001) of fresh placentas had vascular ectasia. These data suggest that large fetal vessels in the placenta become engorged with blood at delivery and, if fixed soon after delivery, remain ectatic and congested when processed for pathology. The identification of artifactual ectasia is important because fetal vessel ectasia can suggest the presence of fetal vascular malperfusion (FVM) if diagnostic signs of FVM are present.

Интеграционный подход в исследовании сосудов плаценты при преэклампсии

Introduction. Preeclampsia is key in obstetric pathology, which is one of the causes of maternal and perinatal morbidity and mortality. It is due to the difficulties of diagnosis, variable clinical picture, severity, and high risk of an unfavorable outcome. This problem requires special attention not only from obstetricians and gynecologists, but also from pathologists who make intravital morphological diagnosis ofplacenta in women with preeclampsia. The purpose of the study was to perform amorphological, morphometric, and immunohistochemical analysis of obliterative angiopathy in the vessels of placental stem villi with preeclampsia of varying severity. Materials and methods.We studied 60 placentas, 40 of which were from women having preeclampsia of varying severity, as well as 20 healthy placentas (the comparison group). For morphometric studies, an automated histological analysis system Leica Application Suite hardware and software module based on a Leica DM4000B microscope was used. The immunohistochemical study was carried out with markers CD34, VEGF-A, and endothelial NOS. Results. We established a directly proportional relationship between the degree of preeclampsia and the severity of arteriole lumen obliteration of the stem villi, and accordingly the degree of placental insufficiency. The most pronounced disorders of fetoplacental circulation were observed in combined severe preeclampsia and extragenital pathology. Conclusion. The data obtained allow us to confirm the significance of obliterative angiopathy in preeclamptic placentas as an integral component. Prevention of ischemic changes in the placenta, where obliterative angiopathy of the villus vessels plays a leading role, is an urgent medical problem that requires an objective approach to predict the condition of the newborn. Keywords: preeclampsia, placenta, obliterative angiopathy, morphometric, immunohistochemical study

Morphological and immunohistochemical parameters of chronic placental insufficiency in preeclampsia

Aim. To determine the morphological parameters of chronic placental insufficiency in pregnancy complicated by preeclampsia, also in women with chronic arterial hypertension (CAH).&#x0D; Materials and Methods. The analysis of history data, peculiarities of pregnancy and childbirth in women with hypertensive disorders was carried out. A review histology of 40 placentas in moderate preeclampsia, 40 placentas in severe preeclampsia, and 35 placentas of women with CAH and associated preeclampsia was performed. The control group consisted of 20 placentas of women with uncomplicated pregnancy without hypertensive disorders. Immunohistochemical examinations were performed on paraffin sections according to standard methods using primary goat antibodies to annexin V (R-20, sc-1929) and rabbit antibodies to erythropoietin (H-162, sc-7556) in a working dilution 1:200 with Super Sensitive IHC polymer detection system.&#x0D; Results. Based on the results of pathomorphological examination of placentas of women with hypertensive disorders, two forms of chronic placental insufficiency were identified. The defining form of placental insufficiency in women with CAH and associated preeclampsia was fetoplacental insufficiency, and in preeclampsia of moderate severity and in severe one utero-placental form of chronic placental insufficiency. Based on the study of the dynamics of expression of annexin V and erythropoietin, morphological parameters of the placental compensatory potential and placental hemostasis disorders in hypertensive disorders in pregnant women were determined.&#x0D; Conclusion. Diagnostic morphological criteria for fetoplacental insufficiency in women with hypertensive disorders are a combination of maternal and fetal malperfusion with obliterative angiopathy of stem villi vessels; in the utero-placental form obliterative angiopathy of spiral arteries, placental hypoperfusion with the development of local hypoxia and hemostatic disorders in the form of thrombosis of the intervillous space and villi infarcts.

Features of the histological structure of trophoblast and chorionic villi with recurrent pregnancy loss in women with thrombophilias

The frequency of recurrent pregnancy loss does not tend to decrease. This pathology continues to be one of the important problems of modern medicine. It is known that thrombophilia can play a significant role in the etiology of spontaneous reproductive losses. However, the pathogenesis of recurrent spontaneous loss of pregnancy in the presence of maternal thrombophilia is not fully understood.&#x0D; Aim. To identify the features of the histological structure of trophoblasts and chorionic villi in the first trimester of pregnancy in women with thrombophilia and recurrent pregnancy loss, with careful exclusion of other possible causes of fetal loss syndrome.&#x0D; Material and Methods. Histological examination of 49 chorion tissue samples from 24 patients with thrombophilia and recurrent pregnancy loss in the first trimester (study group) was performed. The controls were samples of chorion tissue taken during artificial abortion in 33 healthy women who had a history of 2 or more spontaneous labor without significant complications. Thrombophilia diagnosis and hemostasis system state evaluation was performed for all patients on the basis of analysis of 30 parameters according to standard methods. All studies were conducted at the Regional clinical hospital № 8 in Ryazan as well as the scientific and clinical center of hematology, oncology and immunology of the Ryazan State Medical University named after academician I.P. Pavlov of Health Ministry of the Russian Federation. Statistical processing of the obtained results was carried out with the help of computer program package Statistica (version 10).&#x0D; Results. Significant differences in the histological structure of trophoblast and chorionic villi in the studied women were revealed, in comparison with those in the control group. It is proved that the presence of thrombophilia negatively affects the process of embryogenesis and contributes to a significant reduction in the area of the chorionic villus vessels in the first trimester of pregnancy.&#x0D; Conclusion. It is proved that the presence of thrombophilia has a negative effect on the process of embryogenesis and significantly reduces the vascular area of chorionic villi that can probably play a significant role in the pathogenesis of recurrent pregnancy loss.

Fas and FasL expression in placentas complicated with intrauterine growth retardation with and without preeclampsia

Objective: To compare the level of Fas and FasL immunohistochemical expression in villous trophoblast (VT), extravillous trophoblast (EVT) cells, decidual cells (DC), endothelial cells (EC) of villous blood vessels and spiral arteries between the study groups of intrauterine growth retardation (IUGR) placentas with and without preeclampsia (PE).Methods: The study included 17 placentas from pregnancies complicated by IUGR + PE and 17 placentas from pregnancies complicated by idiopathic IUGR (I-IUGR). Seventeen placentas from normal pregnancies served as a control group. CD31 was used to detect endothelial cells (EC). Immunohistochemical expression of Fas and FasL was assessed in all examined parts of placenta using the semi-quantitative HSCORE method.Results: FasL expression was significantly higher in all examined parts of placenta in I-IUGR as compared to IUGR + PE and control group. Placentas with IUGR + PE had the significantly lowest expression of FasL in VT and EC of villi vessels. Expression of Fas did not differ significantly between the study groups.Conclusion: Different expression of FasL in placentas from I-IUGR and IUGR + PE suggests that FasL probably has a different role in the etiology of these two syndromes.

Effect on Cerebral Blood Flow of Orally Administered Indomethacin-loaded Poly(isobutylcyanoacrylate) and Poly(DL-lactide) Nanocapsules

Nanocapsules, containing indomethacin, were prepared either by interfacial polymerization of isobutylcyanoacrylate monomers or by interfacial deposition of a performed (DL-lactide) polymer. In-vitro release of indomethacin from nanocapsules was dependent on the pH of the sink solution and was enhanced by addition of albumin. A decrease in cerebral blood flow was noted 15 min after oral administration to rats of indomethacin nanocapsules (5 mg kg-1) and lasted over 3 h. Empty nanocapsules had no effect. Since release of indomethacin from nanocapsules is unlikely to occur in the lumen of the stomach, due to unsuitable pH conditions, and nanocapsules have been previously shown to be able to cross the intestinal barrier, to reach the villi vessels intact and to protect against the ulcerating effect of the free drug, it is suggested that the rapid onset of the pharmacological effect was sufficiently induced by free indomethacin released in the plasma following absorption of the intact nanocapsules.

Dopplersonographische Befunde bei Nabelschnuranomalien

In cases with different umbilical cord anomalies the influence of foetoplacental resistance on the flow velocity wave forms is discussed. If there is no anastomosis between the two umbilical arteries, the end-diastolic flow velocities depend on the volume of the foetoplacental vessel tree, i.e. higher resistance indices (RI) are found in the arteria with the smaller placental area. If there is only one umbilical artery, the peripheral resistance is reduced to 50%, because the part of the placenta part belonging to this solitary umbilical artery is twofold compared to cases with two umbilical arteries. This leads to a higher perfusion pressure gradient with higher flow velocities and lower RI values, resulting in an underestimation of the foetoplacental resistance. In cases of thrombosis of chorionic membrane vessels or stem villi vessels, placental regions are excluded from the perfusion, followed by an increasing foetoplacental resistance in the same manner as it happens in slowly developing failures of villus maturation. This means that the presented cases of umbilical cord anomalies and function disorders of allantois vessels can be interpreted as an in-vivo model to show pressure and resistance parameters in foetoplacental circulation.

Confocal Laser Scanning Microscope Study of Terminal Villi Vessels in Normal Term and Pre-eclamptic Placentas

The aim of this study was to compare immunocytochemical confocal scanning laser microscopy measures of villus capillarization in control placentas with pre-eclamptic ones. Accordingly, placentas from normal term pregnancies (n=3) and cases of late-onset pre-eclampsia without intrauterine growth retardation (IUGR) featuring normal uterine artery Doppler (n=3) were analyzed by confocal scanning laser microscopy (CSLM), which is a powerful technique for obtaining three-dimensional reconstructions of any kind of blood vessels (arteries, veins, capillaries). A laser light beam is used in order to detect CD34 antibody-related immunofluorescence, which is a marker of endothelial cells. Villus capillarization was assessed by estimating the following parameters: number of pixels, mean, maximum and minimum immunofluorescence amplitude. Our results show a significant hyper-ramification of the capillary loop in pre-eclamptic placentas, featuring irregular profile and narrow lumina. Such findings support the hypothesis that several agents causing angiogenesis and vasoconstriction affect villus vessels in pre-eclamptic placentas, thus promoting a lasting condition of fetal hypoxia by decreasing endothelial surface and materno-fetal exchanges.

Umbilical Vein and Placental Vessels from Newborns with Hereditary Haemorrhagic Telangiectasia Type 1 Genotype are Normal despite Reduced Expression of Endoglin

Hereditary haemorrhagic telangiectasia, HHT, is an autosomal dominant disorder that affects approximately 1 in 8000 people. HHT1 is associated with mutations in the ENG ( Endoglin) gene and with haploinsufficiency. The disorder is characterized by focally dilated vessels, which can lead to arteriovenous malformations and serious complications even in young children. In the current study, umbilical cord and placenta samples from newborns with ENG mutations were analyzed to estimate the level of corresponding protein and look for potential vascular dysplasia. We confirmed, using metabolic labelling and flow cytometry, that endoglin levels were significantly reduced to median values of 47 per cent (range 32–56 per cent) and 58 per cent (46–90 per cent), respectively, in human umbilical vein endothelial cells derived from newborns with ENG mutations (HHT1 group; n=18) relative to samples from newborns shown not to have the familial mutation (non-HHT group). We also quantified the relative expression of endoglin by estimating the endoglin/PECAM-1 staining ratio in tissue sections. We observed significantly lower values in the HHT1 group, compared to the non-HHT group for the umbilical vein ( n=9; median 0.6 vs 0.9; ranges 0.2–1.0 and 0.5–1.5) and for placental stem villus vessels ( n=9 and 10; median 0.42 vs 0.93; ranges 0.24–0.58 and 0.56–1.18). No differences in the estimated umbilical vein cross-sectional area and in the proportion of vessels present in placental villi were observed in sections from the HHT1 group relative to the non-HHT group. Thus, blood vessels from HHT1 individuals are maintained intact in the umbilical vein and placenta during pregnancy and delivery, despite a significant reduction in endoglin expression.

Caveolae and Caveolin-1 in Human Term Villous Trophoblast

Caveolae are flask-shaped invaginations of the plasma membrane found in many cell types, particularly endothelium. A major structural component is the membrane protein caveolin-1 which associates with numerous signalling molecules, including endothelial nitric oxide (eNOS). Caveolin-1, which co-immunoprecipitates with eNOS in preparations from endothelial cells, regulates eNOS activity, holding it inactive. Controversy now exists regarding the presence of caveolae and caveolin-1 in trophoblasts, hence this study was carried out to examine whether the high levels of eNOS expressed in human syncytiotrophoblast are associated with caveolin-1, and to find out if caveolae are present in villous cytotrophoblasts and syncytiotrophoblast. Immunohistochemistry of term placentae revealed only weak labelling for caveolin-1 in the syncytiotrophoblast although the endothelium of the terminal villus vessels stained strongly. By electron microscopy, numerous caveolae were identified in the villus capillary endothelium but were extremely rare in the syncytium. Caveolin-1 staining was extensive in purified, isolated term villous cytotrophoblasts, with the purity of these cytokeratin positive cells confirmed by cytospin analysis and flow cytometry. Caveolae were clearly demonstrated in ultrastructural sections of the purified cytotrophoblasts. The time course of expression of caveolin-1 and eNOS during differentiation of villous cytotrophoblast into syncytiotrophoblast in culture was studied. Western analysis showed that caveolin-1 expression evident in day 1 whole cell lysates decreased at day 3 when the cells had syncytialized and declined further by day 6, while the levels of actin (control) remained high. eNOS expression in the same samples followed a different pattern, with the low levels in day 1 cells increasing substantially by 3 days in culture, subsiding again by day 6. eNOS association with caveolin-1 in day 1 and day 3 trophoblast cultures was evidenced by the demonstration that eNOS co-immunoprecipitates with caveolin-1 and vice versa. We conclude that human villous cytotrophoblasts express caveolin-1, which assembles into caveolae. Differentiation into syncytium results in a decrease, but not disappearance, of expression of caveolin-1 and a marked reduction of the caveolae.

Identification and characterization of 125I-insulin-like growth factor-II binding sites on the muscular layer of stem villi vessels of human term placenta.

The primary function of the placenta is to ensure an optimal environment for fetal growth and development. In normal pregnancy, placental vascular tone regulation assures fetus well-being and normal development by maintaining adequate blood flow so as to ensure materno-fetal exchanges. In human placenta, synthesis of insulin-like growth factor (IGF)-II and specific binding sites have been previously characterized in the trophoblast; in contrast, no studies have dealt with this subject in the fetoplacental vascular system, particularly in stem villi vessels. We thus investigated whether membranes of the muscular layer of stem villi vessels contained 125I-IGF-II binding sites. Two complementary approaches were used: 125I-IGF-II binding and affinity cross-linking studies. 125I-IGF-II labeled, in a saturable and noncooperative manner, a single class of high-affinity binding sites characterized by a Kd of 1.24 +/- 0.26 nM (n = 6), a maximum binding capacity (Bmax) of 3.02 +/- 0.45 pmol/mg protein, and a Hill coefficient of 1.00 +/- 0.15. Competitors for 125I-IGF-II binding to membranes were in the order of potency IGF-II > IGF-I. Insulin was not a competitor. Affinity cross-linking of membranes with 125I-IGF-II, followed by SDS-PAGE and autoradiography, revealed two labeled bands: a protein complex of 250 kDa, which corresponds to the type II IGF receptor, and another of 135 kDa, corresponding to the type I IGF receptor. Only IGF-II could displace 125I-IGF-II binding from the major 250-kDa band, while 125I-IGF-II bound to the minor 135-kDa band was displaced by either IGF-I, IGF-II, or insulin. In conclusion, high levels of specific binding sites for 125I-IGF-II are present in the muscular layer of stem villi vessels, which are considered placenta resistance vessels. The involvement of both type I and type II IGF receptors in the growth-promoting action of IGF-II remains to be determined in the fetoplacental vascular system.

Endothelial modulation of contractile responses of human placental stem villi vessels to endothelins 1 and 3

Endothelial modulation of contractile responses of human placental stem villi vessels to endothelins 1 and 3

Characterization of endothelium-dependent and independent relaxation of human placental stem villi vessels

Characterization of endothelium-dependent and independent relaxation of human placental stem villi vessels

Biochemical characterization and autoradiographic localization of [125I]endothelin-1 binding sites on trophoblast and blood vessels of human placenta.

The presence of endothelin binding sites in the human placenta raises the question of the precise localization of these receptors on well defined placental constituents. In order to find an answer to this problem various approaches were used. Specific binding sites for [125I] endothelin-1 (ET-1) were identified on human term placenta, not only on membranes of smooth muscles stem villi vessels, but also on trophoblastic plasma membranes prepared from trophoblast in culture. Scatchard analysis of binding data revealed a single class of high affinity binding sites with Kd values of 26 +/- 4 pmol/L for stem villi vessels and 126 +/- 4 pmol/L for trophoblast in culture, with maximum binding capacities of 681 +/- 61 and 224 +/- 53 fmol/mg protein, respectively. The anatomical localization of these binding sites was determined by in vitro autoradiography. Autoradiograms obtained from placental sections incubated with [125I]ET-1 indicate that [125I]ET-1 high affinity binding sites exist on placental stem villi vessels and on the trophoblastic layer of the villi. The latter localization was also found on autoradiograms of trophoblast in culture. The human placental syncytiotrophoblast is a polarized epithelium with the microvillous membrane, facing maternal blood space and the basal plasma membrane, facing fetal circulation. [125I]ET-1 high affinity binding sites are present on both membranes but the number of binding sites is higher on the basal plasma membrane. These findings lead to the suggestion that ET-1 may be involved in the regulation of the feto-placental circulation and may subserve specific trophoblastic functions.

Endothelin-1 stimulates inositol phosphate production in smooth muscle of stem villi vessels of human term placenta

Endothelin-1 stimulates inositol phosphate production in smooth muscle of stem villi vessels of human term placenta

Microcirculatory disturbance in indomethacin-induced intestinal ulcer.

Participation of microcirculatory disturbances, especially the role of 5-lipoxygenase products from neutrophils, was investigated in indomethacin (Indo)-induced ulcers of rat small intestine. After Indo treatment (20 mg/kg) in rats, small erosions appeared at 6 h and longitudinal ulcers developed 12 h later. At 6 and 12 h after Indo treatment, severe microcirculatory disturbances were observed under an intravital fluorescence microscope. Significant delay in the clearance and patchy pooling of injected fluorescein isothiocyanate-bovine serum albumin with sludge and stasis were observed in archade vessels of villi of Indo-treated rats. Increased numbers of sticking leukocytes were also detected along submucosal venules in these rats after the infusion of acridine orange. When regional venous blood was collected from the mesentery, a marked increase in neutrophil number and their increased production of oxygen-derived free radicals as determined by chemiluminescence assay were demonstrated at 6 h after Indo treatment. There was also a significant increase in myeloperoxidase activity of the intestinal mucosa at 6 and 12 h after Indo treatment, suggesting a significant neutrophil accumulation at this time. AA-861, a selective inhibitor of 5-lipoxygenase (80 mg/kg), attenuated these microcirculatory changes and neutrophil accumulation in the intestinal mucosa. AA-861 also significantly prevented the formation of intestinal ulcers induced by Indo. However, Indo-induced ulcer formation and leukocyte accumulation in submucosal venules were not attenuated by the treatment of Ono-1078, a potent antagonist of sulfidopeptide leukotrienes. From these observations, it is considered that microcirculatory disturbances, especially leukocyte accumulation and 5-lipoxygenase products, possibly leukotriene B4, may be involved in the development of Indo-induced intestinal ulcer.

Morphological investigation of microscopic mole

Although regulations for treating trophoblastic disease have been established, the diagnostic standards and biological behavior of the microscopic mole are not always described distinctly. I observed morphological changes in the various villi existing between abortion villi and normal villi or total mole and investigated problems related to the microscopic mole. As a result, (1) the disappearance of the villous vessels, central liquefaction and proliferation of the villous cells were observed, though at a low incidence, not only in patients with abortion but also in those with normal villi; (2) When the short axis of the villi was 1,000 microns or less, there were no patients in which villus vessels disappeared, or central liquefaction or proliferation of the villous cells occurred; (3) Among patients with villi having a short axis of 1,000 microns or more, there were patients in whom trophoblastic disease could not be completely distinguished from total mole. A successive tumor developed in 2 patients in the group with (3) findings; (4), I propose that patients who satisfy the criteria in (3), above, should be regarded as those with microscopic mole while others should be regarded as those with hydropic degeneration in a narrow sense.

Identification and characterization of [125I]endothelin binding sites on stem villi vessels from human placenta

Identification and characterization of [125I]endothelin binding sites on stem villi vessels from human placenta

The fetal arterial vasculature in placentas of insulin-dependent diabetic mothers.

Seventeen placentas from insulin-dependent diabetic women and ten placentas from non-diabetics were studied with angiography. The fresh placentas were injected in both umbilical arteries with barium sulphate suspension. After fixation in formaldehyde, the placentas were X-rayed, intact and after being sliced in 0.8 cm slices. There were two clearly distinguishable types of intracotyledonary arteries. Type A is long, narrow and usually runs in the periphery of the cotyledon; type B is wider and usually runs towards the centre of a cotyledon. The cotyledons were classified according to the distribution of these two types of arteries. Type I contained only A-arteries and Type II, both A- and B-arteries or only B-arteries. Twelve per cent of the cotyledons in the control group belonged to Type I, but in the diabetes group 29 per cent. One block of tissue from every placenta was examined histologically to check that the contrast medium filled the stem villus vessels but not the capillaries in the peripheral villi. The histological sections in both groups were compared. Endarteritis appeared to be a feature of the diabetes placenta. The angiographic findings were compared with results of previous direct light microscopical studies. A high percentage of hypovascular villi was found in placentas with a high number of Type I cotyledons.

Use of microspheres to measure small intestinal villus blood flow in the dog.

The accuracy of using 7- to 10-micron microspheres to measure blood flow to dog small intestinal villi was studied. These spheres appear to pass unimpeded through the afferent arterioles of the villus and lodge at the villus tip because 1) virtually all villus spheres were located at the tip, 2) flow determined by visually counting spheres did not differ significantly from flow determined from radioactivity of the sheared-off villus layer, 3) the size distribution of spheres in the villus and subvillus layers was virtually identical to that administered, indicating no premature impaction of the larger spheres, and 4) spheres lodging in the submucosa during vasoconstriction did not subsequently migrate to the villi during vasodilatation. Studies with 25-micron spheres indicated that 28% of the 7- to 10-micron spheres shunted through vessels greater than 10 micron. Double isotope studies showed that lodges spheres do not migrate and that the injection of 2--4 X 10(6) spheres does not alter villus flow. Thus, 7- to 10-micron microspheres pass to and lodge in villus vessels in proportion to capillary flow and should provide an accurate estimate of villus nutrient blood flow.