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Vasculogenesis is the process of blood vessel formation, occurring by a '' de novo'' production of endothelial cells. It is sometimes paired with angiogenesis, as the first stage of the formation of the vascular network, closely followed by angiogenesis.


Process

In the sense distinguished from angiogenesis, vasculogenesis is different in one aspect: whereas angiogenesis is the formation of new blood vessels from pre-existing ones, vasculogenesis is the formation of new blood vessels, in blood islands, when there are no pre-existing ones. For example, if a monolayer of endothelial cells begins sprouting to form capillaries, angiogenesis is occurring. Vasculogenesis, in contrast, is when endothelial precursor cells (
angioblast Angioblasts (or vasoformative cells) are embryonic cells from which the endothelium of blood vessels arises. They are derived from embryonic mesoderm. Blood vessels first make their appearance in several scattered vascular areas that are develope ...
s) migrate and differentiate in response to local cues (such as growth factors and extracellular matrices) 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 The blood circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, t ...
. Specifically, around blood islands, which first arise in the mesoderm of the yolk sac at 3 weeks of development. Vasculogenesis can also occur in the adult organism from circulating endothelial progenitor cells (derivatives of stem cells) able to contribute, albeit to varying degrees, to neovascularization. Examples of where vasculogenesis can occur in adults are: *
Tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...
growth (see
HP59 HP59 is a pathologic angiogenesis capillary endothelial marker protein (7 or 12 transmembrane domains) which has been identified as the receptor for the Group B Streptococcal Toxin (GBS Toxin) molecule known as CM101, the etiologic agent for ea ...
) * Revascularization or neovascularization after
trauma Trauma most often refers to: *Major trauma, in physical medicine, severe physical injury caused by an external source *Psychological trauma, a type of damage to the psyche that occurs as a result of a severely distressing event *Traumatic inju ...
, for example, after cardiac ischemia or retinal ischemia * Endometriosis - It appears that up to 37% of the microvascular endothelium of the ectopic endometrial tissue originates from endothelial progenitor cells.


See also

*
Vasculogenic mimicry __NOTOC__ Vasculogenic mimicry is the formation of microvascular channels by aggressive, metastatic and genetically deregulated tumour cells. This process differs from angiogenesis in that it occurs ''de novo'' without the presence of endothelial ...


References

Embryology of cardiovascular system Cardiovascular physiology {{Circulatory-stub