Talk:Placenta Development: Difference between revisions

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==Original Pages==
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'''Related Pages:''' [http://embryology.med.unsw.edu.au/Notes/placenta7.htm Villi Development] | [http://embryology.med.unsw.edu.au/Notes/placenta8.htm Maternal Decidua] |  [http://embryology.med.unsw.edu.au/Notes/placenta2.htm Placental Abnormalities] | [http://embryology.med.unsw.edu.au/Notes/placenta3.htm  Stage 13/14] | [http://embryology.med.unsw.edu.au/Notes/placenta4.htm  Stage22] |  [http://embryology.med.unsw.edu.au/Notes/placenta5.htm Placental Histology] |  
'''Related Pages:''' [http://embryology.med.unsw.edu.au/Notes/placenta7.htm Villi Development] | [http://embryology.med.unsw.edu.au/Notes/placenta8.htm Maternal Decidua] |  [http://embryology.med.unsw.edu.au/Notes/placenta2.htm Placental Abnormalities] | [http://embryology.med.unsw.edu.au/Notes/placenta3.htm  Stage 13/14] | [http://embryology.med.unsw.edu.au/Notes/placenta4.htm  Stage22] |  [http://embryology.med.unsw.edu.au/Notes/placenta5.htm Placental Histology] |  
[[http://embryology.med.unsw.edu.au/Notes/placenta6.htm  Placental Vascular Beds]  | [http://embryology.med.unsw.edu.au/Notes/heart20.htm Blood] | [http://embryology.med.unsw.edu.au/Notes/heart19.htm Blood Vessels] | [http://embryology.med.unsw.edu.au/Child/birth1.htm Birth] | [http://embryology.med.unsw.edu.au/Notes/stemcell4.htm Stem Cells - Cord Blood]
[[http://embryology.med.unsw.edu.au/Notes/placenta6.htm  Placental Vascular Beds]  | [http://embryology.med.unsw.edu.au/Notes/heart20.htm Blood] | [http://embryology.med.unsw.edu.au/Notes/heart19.htm Blood Vessels] | [http://embryology.med.unsw.edu.au/Child/birth1.htm Birth] | [http://embryology.med.unsw.edu.au/Notes/stemcell4.htm Stem Cells - Cord Blood]
Placenta Links: [[Placenta - Villi Development]] | [[Placenta - Maternal Decidua]] | [[Placenta - Abnormalities]] | [[Placenta - Stage 13/14]] | [[Placenta - Histology]] |  [[Placenta - Stage22]] | [[Placenta - Vascular Beds]]
===Placental Abnormalities===
* placenta accreta one abnormally adherent to the myometrium, with partial or complete absence of the decidua basalis.
* battledore placenta one with the umbilical cord inserted at the edge.
* placenta circumvallata one encircled with a dense, raised, white nodular ring, the attached membranes being doubled back over the edge of the placenta.
* placenta fenestrata one that has spots where placental tissue is lacking.
* placenta increta placenta accreta with penetration of the myometrium.
* placenta membrana´cea one that is abnormally thin and spread over an unusually large area of the myometrium.
* placenta percreta placenta accreta with invasion of the myometrium to the peritoneal covering, sometimes causing rupture of the uterus.
* placenta previa low implantation of the placenta so that it partially or completely covers the cervical os. Percentages are used to designate the amount of obstruction; e.g., 100 per cent is total placenta previa, and 50 per cent indicates that about half the opening is obstructed. The condition occurs with greater frequency in women who have had multiple pregnancies or are over 35. The exact cause is not known.




Placenta Links: [[Placenta - Villi Development]] | [[Placenta - Maternal Decidua]] | [[Placenta - Abnormalities]] | [[Placenta - Stage 13/14]] | [[Placenta - Histology]] |  [[Placenta - Stage22]] | [[Placenta - Vascular Beds]]


==2010==
==2010==

Revision as of 20:01, 6 April 2011

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Cite this page: Hill, M.A. (2024, March 29) Embryology Placenta Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Placenta_Development

Original Pages

Related Pages: Villi Development | Maternal Decidua | Placental Abnormalities | Stage 13/14 | Stage22 | Placental Histology | [Placental Vascular Beds | Blood | Blood Vessels | Birth | Stem Cells - Cord Blood

Placenta Links: Placenta - Villi Development | Placenta - Maternal Decidua | Placenta - Abnormalities | Placenta - Stage 13/14 | Placenta - Histology | Placenta - Stage22 | Placenta - Vascular Beds

Placental Abnormalities

  • placenta accreta one abnormally adherent to the myometrium, with partial or complete absence of the decidua basalis.
  • battledore placenta one with the umbilical cord inserted at the edge.
  • placenta circumvallata one encircled with a dense, raised, white nodular ring, the attached membranes being doubled back over the edge of the placenta.
  • placenta fenestrata one that has spots where placental tissue is lacking.
  • placenta increta placenta accreta with penetration of the myometrium.
  • placenta membrana´cea one that is abnormally thin and spread over an unusually large area of the myometrium.
  • placenta percreta placenta accreta with invasion of the myometrium to the peritoneal covering, sometimes causing rupture of the uterus.
  • placenta previa low implantation of the placenta so that it partially or completely covers the cervical os. Percentages are used to designate the amount of obstruction; e.g., 100 per cent is total placenta previa, and 50 per cent indicates that about half the opening is obstructed. The condition occurs with greater frequency in women who have had multiple pregnancies or are over 35. The exact cause is not known.


2010

Placental surface shape, function, and effects of maternal and fetal vascular pathology

Placenta. 2010 Oct 6. [Epub ahead of print]

Salafia CM, Yampolsky M, Misra DP, Shlakhter O, Haas D, Eucker B, Thorp J.

Placental Analytics, LLC, 93 Colonial Avenue, Larchmont, NY 10538, USA; Department of Obstetrics and Gynecology and Pediatrics, New York Methodist Hospital, Brooklyn, NY, USA. Abstract

GOAL: In clinical practice, variability of placental surface shape is common. We measure the average placental shape in a birth cohort and the effect deviations from the average have on placental functional efficiency. We test whether altered placental shape improves the specificity of histopathology diagnoses of maternal uteroplacental and fetoplacental vascular pathology for clinical outcomes.

MATERIALS AND METHODS: 1225 Placentas from a prospective cohort had chorionic plate digital photographs with perimeters marked at 1-2 cm intervals. After exclusions of pre-term (n = 202) and velamentous cord insertion (n = 44), 979 (95.7%) placentas were analyzed. Median shape and mean perimeter were estimated. The relationship of fetal and placental weight was used as an index of placental efficiency termed "β". The principal placental histopathology diagnoses of maternal uteroplacental and fetoplacental vascular pathologies were coded by review of individual lesion scores. Acute fetal inflammation was scored as a "negative control" pathology not expected to affect shape. ANOVA with Bonferroni tests for subgroup comparisons were used.

RESULTS: The mean placental chorionic shape at term was round with a radius estimated at 9.1 cm. Increased variability of the placental shape was associated with lower placental functional efficiency. After stratifying on placental shape, the presence of either maternal uteroplacental or fetoplacental vascular pathology was significantly associated with lower placental efficiency only when shape was abnormal.

CONCLUSIONS: Quantifying abnormality of placental shape is a meaningful clinical tool. Abnormal shapes are associated with reduced placental efficiency. We hypothesize that such shapes reflect deformations of placental vascular architecture, and that an abnormal placental shape serves as a marker of maternal uteroplacental and/or fetoplacental vascular pathology of sufficiently long standing to impact placental (and by extension, potentially fetal) development. Copyright © 2010 Elsevier Ltd. All rights reserved.

PMID: 2093328

2007

The architecture of first trimester chorionic villous vascularization: a confocal laser scanning microscopical study

Hum Reprod. 2007 Aug;22(8):2254-60. Epub 2007 Jun 1.

Lisman BA, van den Hoff MJ, Boer K, Bleker OP, van Groningen K, Exalto N.

Department of Obstetrics and Gynaecology, Academic Medical Centre, University of Amsterdam, PO Box 22700, 1100 DE Amsterdam, The Netherlands. b.a.lisman@amc.uva.nl Abstract BACKGROUND: The aim of this study was to investigate normal chorionic villous vascularization using CD31 immunofluorescence and confocal laser scanning microscopy (CLSM) to elucidate the spatial arrangement in terms of connections between vessels and cords and their branching patterns compared to deficient chorionic villous vascularization in complicated pregnancies.

METHODS: A descriptive morphologic study using CLSM after CD31 immunofluorescence staining of placental biopsies from normal pregnancies (n = 20), complete hydatidiform molar pregnancies (CHMs; n = 3) and empty sacs (n = 3), with a well documented gestational age (GA).

RESULTS: In this three-dimensional study, first trimester chorionic villi were occupied by a complex network of mainly cords with redundant connections as early as 5(+5) weeks GA. With increasing GA cords transform into vessels. From about 9 weeks GA onwards, vascular development is characterized by the presence of two large vessels located centrally and surrounded by and connected to a capillary network. In first trimester CHM and empty sacs, we observed a primitive network of mainly cords.

CONCLUSIONS: This first visualization of the spatio-temporal patterns of blood vessel formation in placental villi is characterized by the development of the vasculosyncytial membrane from a complex network of cords and can be regarded as the placental development before it becomes functional at the end of organogenesis.

PMID: 17545656 http://www.ncbi.nlm.nih.gov/pubmed/17545656

http://humrep.oxfordjournals.org/content/22/8/2254.long

Timing below - gestational age (LMP)

  • 3- 4 weeks (5 and 6 weeks GA) - a complex network of cords and vessels with redundant connections in chorionic villi is seen. This network comprises mainly cords, already connected together. All vessels and cords are connected to each other without any interruptions. The chorionic villus is completely dominated by a network of vascular elements. Vessels and cords are located centrally as well as peripherally and as a consequence contact the overlying trophoblastic layer (Fig. 1A and B). The luminal diameter of the vessels ranges between 10 and 15 µm (Table 1).


  • 5-6 weeks (7 and 8 weeks GA) - chorionic villi are dominated by a capillary network consisting of vessels and cords. The capillary network contains more vessels than cords. At the tip of the chorionic villus, regular small branched off (mesenchymal) chorionic villi are observed containing a conglomeration of CD31 positive cells (Fig. 2). The luminal diameter of the vessels, ranging between 10 and 26 µm, has increased compared with the earlier stage.
  • 7-8 weeks (9 and 10 weeks GA) - chorionic villi are characterized by the presence of two large vessels located centrally and surrounded by and connected to a capillary network at the periphery of the villus. The capillary network contains mainly vessels with a lumen that are in tight contact with the overlying trophoblastic layer (Fig. 3A and B). From this GA onwards, we observed villous projections containing blindly ending capillary sprouts arising from the underlying capillary network. The luminal diameter of the two centrally located vessels varies between 60 and 75 µm, whereas the vessels of the capillary network range between 26 and 34 µm (Table 1).
  • 9-10 weeks (11 and 12 weeks GA) - immature intermediate villi are characterized by the presence of two large vessels surrounded by a capillary network. Within the network, cords are infrequently present. Blindly ending capillary sprouts branching off the capillary network are present (Fig. 4). The centrally located large vessels range between 70 and 90 µm in diameter and are wider than the vessels between 9 and 10 weeks GA. However, the diameter of the vessels of the capillary network is similar to the previous stage

Fetal vasculogenesis and angiogenesis in human placental villi

Acta Anat (Basel). 1989;136(3):190-203.

Demir R, Kaufmann P, Castellucci M, Erbengi T, Kotowski A.

Department of Histology and Embryology, Faculty of Medicine, Akdeniz University, Antalya, Turkey. Abstract Placental villi of 5 exactly defined early human specimens ranging from day 21 post conception (p.c.) until day 42 p.c. and from an additional 43 specimens from about 5 to 40 weeks menstrual age have been analyzed ultrastructurally with regard to fetal vasculogenesis and angiogenesis. The following results were obtained: The first cells differentiating at day 21 p.c., probably originating from mesenchymal precursors, are macrophage-like cells. At almost the same time, mesenchymal cells transform into haemangioblastic cell cords which are the forerunners of the capillary endothelium and haematopoietic stem cells. A third cell population related to the fetal circulatory system and derived from the mesenchymal cells are presumptive pericytes. Capillary formation takes place by the aggregation of haemangioblastic cells which are attached to each other by intercellular junctions. The lumen is formed by the dehiscence of the intercellular clefts. A capillary basal lamina cannot be detected earlier than in the last trimester. In this last period of gestation, fetal villous angiogenesis takes place by the proliferation of the existing endothelium and pericytes rather than via haemangioblastic cells.


  • Vascularization of the placenta takes place around day 21 post conception (p.c.) endothelial progenitor cells appear as cords right beneath the trophoblastic layer. which are called angiogenic cell cords (ACC).
  • These cells proliferate, differentiate and migrate to form main vascular patterns and form primitive vascular tubes (VT), which demonstrate a primitive lumen formation.

PMID: 2481376 http://www.ncbi.nlm.nih.gov/pubmed/2481376

Placenta Issue

Vol. 54 Nos. 2/3 (2010)

http://www.ijdb.ehu.es/web/contents.php?vol=54&issue=2-3

Anthropometry of fetal vasculature in the chorionic plate

Gordon Z, Elad D, Almog R, Hazan Y, Jaffa AJ, Eytan O. J Anat. 2007 Dec;211(6):698-706. Epub 2007 Oct 30. PMID: 17973911

http://onlinelibrary.wiley.com/doi/10.1111/j.1469-7580.2007.00819.x/full

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2697319/figure/fig1/

A photomicrograph of the human endometrium on the fourth day of menstruation showing an eroded spiral artery (arrowed) projecting freely into the uterine lumen. b) A photomicrograph of spiral arteries in a rhesus monkey during the phase of ovulation injected with India ink in gelatin. The arrow marks the endometrial–myometrial boundary, and a marked constriction (asterisked) can be seen in the spiral artery in the junctional zone just below. c) Reconstruction from serial sections of a converted spiral artery passing through the myometrium (M) and endometrium (E) before opening into the intervillous space through the basal plate of a term placenta. The widest dimension of the opening is given as 2.4 mm. Reproduced from Refs. [83], [15] and [16] respectively with permission of the Carnegie Institute of Washington.

Immunology of placentation in eutherian mammals

http://www.nature.com/nri/journal/v6/n8/full/nri1897.html

The human placenta is a hematopoietic organ during the embryonic and fetal periods of development

http://www.ncbi.nlm.nih.gov/pubmed/19073167

"We studied the potential role of the human placenta as a hematopoietic organ during embryonic and fetal development. Placental samples contained two cell populations-CD34(++)CD45(low) and CD34(+)CD45(low)-that were found in chorionic villi and in the chorioamniotic membrane. CD34(++)CD45(low) cells express many cell surface antigens found on multipotent primitive hematopoietic progenitors and hematopoietic stem cells. CD34(++)CD45(low) cells contained colony-forming units culture (CFU-C) with myeloid and erythroid potential in clonogenic in vitro assays, and they generated CD56(+) natural killer cells and CD19(+)CD20(+)sIgM(+) B cells in polyclonal liquid cultures. CD34(+)CD45(low) cells mostly comprised erythroid- and myeloid-committed progenitors, while CD34(-) cells lacked CFU-C. The placenta-derived precursors were fetal in origin, as demonstrated by FISH using repeat-sequence chromosome-specific probes for X and Y. The number of CD34(++)CD45(low) cells increased with gestational age, but their density (cells per gram of tissue) peaked at 5-8 wk, decreasing more than sevenfold at the onset of the fetal phase (9 wk of gestation). In addition to multipotent progenitors, the placenta contained myeloid- and erythroid-committed progenitors indicative of active in situ hematopoiesis. These data suggest that the human placenta is an important hematopoietic organ, raising the possibility of banking placental hematopoietic stem cells along with cord blood for transplantation."

De novo synthesis of estrogen in pregnant uterus is critical for stromal decidualization and angiogenesis. Das A, Mantena SR, Kannan A, Evans DB, Bagchi MK, Bagchi IC. Proc Natl Acad Sci U S A. 2009 Jul 28;106(30):12542-7. Epub 2009 Jul 20. Erratum in: Proc Natl Acad Sci U S A. 2009 Sep 15;106(37):16003. PMID: 19620711 | PNAS

  • Implantation is initiated when the embryo attaches to the uterine luminal epithelium during early pregnancy.
  • Following this event, uterine stromal cells undergo steroid hormone-dependent transformation into morphologically and functionally distinct decidual cells in a unique process known as decidualization.
  • An angiogenic network is also formed in the uterine stromal bed, critically supporting the early development of the embryo.
  • ovarian progesterone as a key regulator of decidualization is well established
  • these studies in mice - identified the decidual uterus as a novel site of estrogen biosynthesis and uncovered estrogen-regulated maternal signaling pathways that critically control uterine differentiation and angiogenesis during early pregnancy.


Classification of human placental stem villi: review of structural and functional aspects

Microsc Res Tech. 1997 Jul 1-15;38(1-2):29-41.

Demir R, Kosanke G, Kohnen G, Kertschanska S, Kaufmann P.

Department of Histology and Embryology, Medical Faculty, Akdeniz University, Antalya, Turkey. Abstract The stem villi of the human placenta represent the central branches of the villous trees. They are characterized by a condensed fibrous stroma in which the fetal arteries and veins as well as the arterioles and venules are embedded. Functionally they are accepted as the mechanically supporting structures of the villous trees, and they are supposed to control fetal blood flow to the maternofetal exchange area, which is located in the peripheral villi. To obtain further insights into the functions of the stem villi, the recent literature has been reviewed, and some immunohistochemical, ultrastructural, and reconstruction studies have been added. These new studies were aimed at identifying immunohistochemically different subtypes of stem villi, their branching patterns, the distribution of macrophages, the stromal proliferation patterns, and the differentiation of extravascular stromal cells. Our findings demonstrate that the stem villi and their precursors, the immature intermediate villi, can selectively be identified by anti-gamma-smooth muscle (sm) actin staining. Furthermore, the existence of three different subtypes of stem villi is shown; these differ regarding the presence and distribution of gamma-sm actin-positive cells. These cells were immunohistochemically and ultrastructurally identified as smooth muscle cells and myofibroblasts. Increasingly complex coexpression patterns of cytoskeletal proteins reflect a clearly defined differentiation gradient of extravascular stromal cells, which covers the whole range of an undifferentiated germinative layer beneath the trophoblast to highly differentiated myofibroblasts surrounding the medias of the stem vessels. Possible functions of the extravascular contractile system include the regulation of villous turgor and the control of intervillous blood flow impedance.

PMID: 9260835