Vasculogenesis
Encyclopedia
Vasculogenesis is the process of blood vessel
Blood vessel
The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...

 formation occurring by a de novo
De novo
In general usage, de novo is a Latin expression meaning "from the beginning," "afresh," "anew," "beginning again." It is used in:* De novo transcriptome assembly, the method of creating a transcriptome without a reference genome...

production of endothelial cells.

Process

Though similar to angiogenesis
Angiogenesis
Angiogenesis is the physiological process involving the growth of new blood vessels from pre-existing vessels. Though there has been some debate over terminology, vasculogenesis is the term used for spontaneous blood-vessel formation, and intussusception is the term for the formation of new blood...

, the two are different in one aspect: The term angiogenesis denotes the formation of new blood vessels from pre-existing ones, whereas vasculogenesis is the term used for the formation of new blood vessels when there are no pre-existing ones. For example, if a monolayer
Monolayer
- Chemistry :A Langmuir monolayer or insoluble monolayer is a one-molecule thick layer of an insoluble organic material spread onto an aqueous subphase. Traditional compounds used to prepare Langmuir monolayers are amphiphilic materials that possess a hydrophilic headgroup and a hydrophobic tail...

 of endothelial cells begins sprouting to form capillaries
Capillary
Capillaries are the smallest of a body's blood vessels and are parts of the microcirculation. They are only 1 cell thick. These microvessels, measuring 5-10 μm in diameter, connect arterioles and venules, and enable the exchange of water, oxygen, carbon dioxide, and many other nutrient and waste...

, angiogenesis is occurring. Vasculogenesis, in contrast, is when endothelial precursor cells (angioblasts) migrate and differentiate in response to local cues (such as growth factors and extracellular matrix) to form new blood vessels. These vascular trees are then pruned and extended through angiogenesis.

Occurrences

Vasculogenesis occurs during embryologic development of the circulatory system.

Vasculogenesis can also occur in the adult organism from circulating endothelial progenitor cell
Endothelial progenitor cell
Endothelial progenitor cells are a population of rare cells that circulate in the blood with the ability to differentiate into endothelial cells, the cells that make up the lining of blood vessels. The process by which blood vessels are born de novo from endothelial progenitor cells is known as...

s (derivatives of stem cells) able to contribute, albeit to varying degrees, to neovascularization. Examples of where vasculogenesis can occur in adults are:
  • during tumor
    Tumor
    A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...

     growth
  • revascularization process following trauma, e.g., after cardiac ischemia
    Ischemia
    In medicine, ischemia is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. It may also be spelled ischaemia or ischæmia...

  • Endometriosis
    Endometriosis
    Endometriosis is a gynecological medical condition in which cells from the lining of the uterus appear and flourish outside the uterine cavity, most commonly on the ovaries. The uterine cavity is lined by endometrial cells, which are under the influence of female hormones...

     - It appears that that up to 37% of the microvascular endothelium of the ectopic endometrial tissue originates from endothelial progenitor cell
    Endothelial progenitor cell
    Endothelial progenitor cells are a population of rare cells that circulate in the blood with the ability to differentiate into endothelial cells, the cells that make up the lining of blood vessels. The process by which blood vessels are born de novo from endothelial progenitor cells is known as...

    s.
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