Chorionic villi

Last updated
Chorionic villi
ChorionicVillus.png
Details
Days24
Identifiers
MeSH D002824
Anatomical terminology

Chorionic villi are villi that sprout from the chorion to provide maximal contact area with maternal blood.

Contents

They are an essential element in pregnancy from a histomorphologic perspective, and are, by definition, a product of conception. Branches of the umbilical arteries carry embryonic blood to the villi. After circulating through the capillaries of the villi, blood returns to the embryo through the umbilical vein. Thus, villi are part of the border between maternal and fetal blood during pregnancy.

Structure

Primary chorionic villi. Gray36.png
Primary chorionic villi.
Tertiary chorionic villi. Gray37.png
Tertiary chorionic villi.

Villi can also be classified by their relations:

Development

The chorion undergoes rapid proliferation and forms numerous processes, the chorionic villi, which invade and destroy the uterine decidua and at the same time absorb from it nutritive materials for the growth of the embryo. They undergo several stages, depending on their composition.

StageDescriptionPeriod of gestationContents
PrimaryThe chorionic villi are at first small and non-vascular.13–15 days trophoblast only [1]
SecondaryThe villi increase in size and ramify, while the mesoderm grows into them.16–21 daystrophoblast and mesoderm [1]
TertiaryBranches of the umbilical artery and umbilical vein grow into the mesoderm, and in this way the chorionic villi are vascularized.17–22 daystrophoblast, mesoderm, and blood vessels [1]

Until about the end of the second month of pregnancy, the villi cover the entire chorion, and are almost uniform in size—but after then, they develop unequally.

Microanatomy

Histopathology of a chorionic villus, in a tubal pregnancy. Histopathology of tubal pregnancy.jpg
Histopathology of a chorionic villus, in a tubal pregnancy.

The bulk of the villi consist of connective tissues that contain blood vessels. Most of the cells in the connective tissue core of the villi are fibroblasts. Macrophages known as Hofbauer cells are also present.

Clinical significance

Use for prenatal diagnosis

In 1983, an Italian biologist named Giuseppe Simoni discovered a new method of prenatal diagnosis using chorionic villi.

Stem cell

Chorionic villi are a rich source of stem cells. Biocell Center, a biotech company managed by Giuseppe Simoni, is studying and testing these types of stem cells. Chorionic stem cells, like amniotic stem cells, are uncontroversial multipotent stem cells. [2] [3] [4]

Infections

Recent studies indicate that the chorionic villi may be susceptible to bacterial [5] and viral infections. Recents findings indicate that ureaplasma parvum can infect the chorionic villi tissues of pregnant women, thereby impacting pregnancy outcome. [6] DNA from JC polyomavirus and Merkel cell polyomavirus has been detected in chorionic villi from pregnant women and women affected by miscarriage. [7] [8] DNA from BK polyomavirus has also been detected in the same tissues but to a lesser extent. [7]

Early miscarriage

Gross pathology of chorionic villi after a miscarriage. Gross pathology of fixed chorionic villi.jpg
Gross pathology of chorionic villi after a miscarriage.

In early miscarriage, the finding of chorionic villi in vaginal expulsions is often the only definite confirmation that there was an intrauterine pregnancy rather than an ectopic pregnancy.

Additional images

See also

Related Research Articles

<span class="mw-page-title-main">Pregnancy (mammals)</span> Period of reproduction

In mammals, pregnancy is the period of reproduction during which a female carries one or more live offspring from implantation in the uterus through gestation. It begins when a fertilized zygote implants in the female's uterus, and ends once it leaves the uterus.

<span class="mw-page-title-main">Miscarriage</span> Natural death and expulsion of an embryo or fetus before its independent survival

Miscarriage, also known in medical terms as a spontaneous abortion, is the death and expulsion of an embryo or fetus before it can survive independently. The term miscarriage is sometimes used to refer to all forms of pregnancy loss and pregnancy with abortive outcomes before 20 weeks of gestation.

<span class="mw-page-title-main">Amniocentesis</span> Sampling of amniotic fluid done mainly to detect fetal chromosomal abnormalities

Amniocentesis is a medical procedure used primarily in the prenatal diagnosis of genetic conditions. It has other uses such as in the assessment of infection and fetal lung maturity. Prenatal diagnostic testing, which includes amniocentesis, is necessary to conclusively diagnose the majority of genetic disorders, with amniocentesis being the gold-standard procedure after 15 weeks' gestation.

<span class="mw-page-title-main">Chorion</span> Outermost fetal membrane around the embryo in amniotes

The chorion is the outermost fetal membrane around the embryo in mammals, birds and reptiles (amniotes). It develops from an outer fold on the surface of the yolk sac, which lies outside the zona pellucida, known as the vitelline membrane in other animals. In insects, it is developed by the follicle cells while the egg is in the ovary. Some mollusks also have chorions as part of their eggs. For example, fragile octopus eggs have only a chorion as their envelope.

Mycoplasma hominis is a species of bacteria in the genus Mycoplasma. M. hominis has the ability to penetrate the interior of human cells. Along with ureaplasmas, mycoplasmas are the smallest free-living organisms known.

<span class="mw-page-title-main">Blastocyst</span> Structure formed around day 5 of mammalian embryonic development

The blastocyst is a structure formed in the early embryonic development of mammals. It possesses an inner cell mass (ICM) also known as the embryoblast which subsequently forms the embryo, and an outer layer of trophoblast cells called the trophectoderm. This layer surrounds the inner cell mass and a fluid-filled cavity or lumen known as the blastocoel. In the late blastocyst, the trophectoderm is known as the trophoblast. The trophoblast gives rise to the chorion and amnion, the two fetal membranes that surround the embryo. The placenta derives from the embryonic chorion and the underlying uterine tissue of the mother.

<span class="mw-page-title-main">Chorionic villus sampling</span> Type of prenatal diagnosis done to determine chromosomal or genetic disorders in the fetus

Chorionic villus sampling (CVS), sometimes called "chorionic villous sampling", is a form of prenatal diagnosis done to determine chromosomal or genetic disorders in the fetus. It entails sampling of the chorionic villus and testing it for chromosomal abnormalities, usually with FISH or PCR. CVS usually takes place at 10–12 weeks' gestation, earlier than amniocentesis or percutaneous umbilical cord blood sampling. It is the preferred technique before 15 weeks.

<i>Human polyomavirus 2</i> Species of virus

Human polyomavirus 2, commonly referred to as the JC virus or John Cunningham virus, is a type of human polyomavirus. It was identified by electron microscopy in 1965 by ZuRhein and Chou, and by Silverman and Rubinstein. It was later isolated in culture and named using the initials of a patient by the name of John Cunningham from whom it was isolated and had developed progressive multifocal leukoencephalopathy (PML). The virus causes leukoencephalopathy and other diseases only in cases of immunodeficiency, as in AIDS or during treatment with immunosuppressive drugs.

<i>Ureaplasma urealyticum</i> Species of bacterium

Ureaplasma urealyticum is a bacterium belonging to the genus Ureaplasma and the family Mycoplasmataceae in the order Mycoplasmatales. This family consists of the genera Mycoplasma and Ureaplasma. Its type strain is T960. There are two known biovars of this species; T960 and 27. These strains of bacteria are commonly found as commensals in the urogenital tracts of human beings, but overgrowth can lead to infections that cause the patient discomfort. Unlike most bacteria, Ureaplasma urealyticum lacks a cell wall making it unique in physiology and medical treatment.

A peripheral blood mononuclear cell (PBMC) is any peripheral blood cell having a round nucleus. These cells consist of lymphocytes and monocytes, whereas erythrocytes and platelets have no nuclei, and granulocytes have multi-lobed nuclei. In humans, lymphocytes make up the majority of the PBMC population, followed by monocytes, and only a small percentage of dendritic cells.

<span class="mw-page-title-main">BK virus</span> Member of the polyomavirus family

The BK virus, also known as Human polyomavirus 1, is a member of the polyomavirus family. Past infection with the BK virus is widespread, but significant consequences of infection are uncommon, with the exception of the immunocompromised and the immunosuppressed. BK virus is an abbreviation of the name of the first patient, from whom the virus was isolated in 1971.

<span class="mw-page-title-main">Syncytiotrophoblast</span> Embryonic cell of the placental surface

The syncytiotrophoblast is the epithelial covering of the highly vascular embryonic placental villi, which invades the wall of the uterus to establish nutrient circulation between the embryo and the mother. It is a multinucleate, terminally differentiated syncytium, extending to 13 cm.

<span class="mw-page-title-main">Placentation</span> Formation and structure of the placenta

Placentation is the formation, type and structure, or arrangement of the placenta. The function of placentation is to transfer nutrients, respiratory gases, and water from maternal tissue to a growing embryo, and in some instances to remove waste from the embryo. Placentation is best known in live-bearing mammals (Theria), but also occurs in some fish, reptiles, amphibians, a diversity of invertebrates, and flowering plants. In vertebrates, placentas have evolved more than 100 times independently, with the majority of these instances occurring in squamate reptiles.

Tissue inhibitors of metalloproteinases (TIMPs) are specific endogenous protease inhibitors to the matrix metalloproteinases. There are four TIMPs; TIMP1, TIMP2, TIMP3 and TIMP4. TIMP3 has been observed progressively downregulated in Human papillomavirus-positive neoplastic keratinocytes derived from uterine cervical preneoplastic lesions at different levels of malignancy. For this reason, TIMP3 is likely to be associated with tumorigenesis and may be a potential prognostic marker for uterine cervical preneoplastic lesions progression.

Merkel cell polyomavirus was first described in January 2008 in Pittsburgh, Pennsylvania. It was the first example of a human viral pathogen discovered using unbiased metagenomic next-generation sequencing with a technique called digital transcriptome subtraction. MCV is one of seven currently known human oncoviruses. It is suspected to cause the majority of cases of Merkel cell carcinoma, a rare but aggressive form of skin cancer. Approximately 80% of Merkel cell carcinoma (MCC) tumors have been found to be infected with MCV. MCV appears to be a common—if not universal—infection of older children and adults. It is found in respiratory secretions, suggesting that it might be transmitted via a respiratory route. However, it has also been found elsewhere, such as in shedded healthy skin and gastrointestinal tract tissues, thus its precise mode of transmission remains unknown. In addition, recent studies suggest that this virus may latently infect the human sera and peripheral blood mononuclear cells.

<span class="mw-page-title-main">Chorionic hematoma</span> Medical condition

Chorionic hematoma is the pooling of blood (hematoma) between the chorion, a membrane surrounding the embryo, and the uterine wall. It occurs in about 3.1% of all pregnancies, it is the most common sonographic abnormality and the most common cause of first trimester bleeding.

<span class="mw-page-title-main">Fetal membranes</span> Amnion and chorion which surround and protect a developing fetus

The fetal membranes are the four extraembryonic membranes, associated with the developing embryo, and fetus in humans and other mammals. They are the amnion, chorion, allantois, and yolk sac. The amnion and the chorion are the chorioamniotic membranes that make up the amniotic sac which surrounds and protects the embryo. The fetal membranes are four of six accessory organs developed by the conceptus that are not part of the embryo itself, the other two are the placenta, and the umbilical cord.

<span class="mw-page-title-main">IRX2</span> Protein-coding gene in the species Homo sapiens

Iroquois-class homeodomain protein IRX-2, also known as Iroquois homeobox protein 2, is a protein that in humans is encoded by the IRX2 gene.

<span class="mw-page-title-main">Products of conception</span>

Products of conception, abbreviated POC, is a medical term used for the tissue derived from the union of an egg and a sperm. It encompasses anembryonic gestation which does not have a viable embryo.

Massive perivillous fibrin deposition refers to excessive deposition of fibrous tissue around the chorionic villi of the placenta. It causes reduced growth of the foetus, and leads to miscarriage in nearly 1 in 3 pregnancies affected. There are typically no symptoms, and it is rarely detected before birth. The cause is unknown, but may be autoimmune. Diagnosis is based on the histology of the placenta. There are currently no known treatments. MPFD is very rare, but recurrence is around 18% in those affected.

References

PD-icon.svgThis article incorporates text in the public domain from page 60 of the 20th edition of Gray's Anatomy (1918)

  1. 1 2 3 Larsen, William J. : Human embryology. Sherman, Lawrence S.; Potter, S. Steven; Scott, William J. 3. ed.
  2. "European Biotech Company Biocell Center Opens First U.S. Facility for Preservation of Amniotic Stem Cells in Medford, Massachusetts | Reuters". 2009-10-22. Retrieved 2010-01-11.[ dead link ]
  3. "Europe's Biocell Center opens Medford office – Daily Business Update – The Boston Globe". 2009-10-22. Retrieved 2010-01-11.
  4. "The Ticker - BostonHerald.com". Archived from the original on 2012-09-21. Retrieved 2010-01-11.
  5. Contini C, Rotondo JC, Magagnoli F, Maritati M, Seraceni S, Graziano A (2019). "Investigation on silent bacterial infections in specimens from pregnant women affected by spontaneous miscarriage". J Cell Physiol. 34 (3): 433–440. doi: 10.1002/jcp.26952 . hdl: 11392/2393176 . PMID   30078192.
  6. Contini C, Rotondo JC, Magagnoli F, Maritati M, Seraceni S, Graziano A, Poggi A, Capucci R, Vesce F, Tognon M, Martini F (2018). "Investigation on silent bacterial infections in specimens from pregnant women affected by spontaneous miscarriage". J Cell Physiol. 234 (1): 100–9107. doi: 10.1002/jcp.26952 . hdl: 11392/2393176 . PMID   30078192.
  7. 1 2 Tagliapietra A, Rotondo JC, Bononi I, Mazzoni E, Magagnoli F, Maritati M (2019). "Footprints of BK and JC polyomaviruses in specimens from females affected by spontaneous abortion". Hum Reprod. 34 (3): 433–440. doi:10.1002/jcp.27490. hdl: 11392/2397717 . PMID   30590693. S2CID   53106591.
  8. Tagliapietra A, Rotondo JC, Bononi I, Mazzoni E, Magagnoli F, Maritati M (2020). "Droplet-digital PCR assay to detect Merkel cell polyomavirus sequences in chorionic villi from spontaneous abortion affected females". J Cell Physiol. 235 (3): 1888–1894. doi: 10.1002/jcp.29213 . hdl: 11392/2409453 . PMID   31549405.