Perivascular Spaces

Perivascular spaces (spatia perivascularia, lnh; synonym: Virchow spaces) are slit-like spaces surrounding blood vessels. They are part of connective tissue and filled with interstitial fluid.

Perivascular spaces play an important role in the regulation of blood circulation. They allow blood vessels to expand and contract, regulating blood flow. In addition, these spaces are involved in the transport of nutrients and the removal of metabolic products from tissue cells to blood vessels.

Perivascular spaces were first described by German pathologist Rudolf Virchow in 1858 and are therefore sometimes also called Virchow's spaces. Studying the perivascular spaces is important for understanding the pathophysiology of diseases such as edema, inflammation, atherosclerosis and hypertension.

The perivascular layer or perivascular space is an interstitial tissue formation that surrounds blood vessels and connects it to the walls lining the mucous membrane with connective tissue. This space lies between the endothelium and the fibrous capsule. It includes the vascular walls and surrounding tissues, which it connects functionally and structurally through slits in the perivascular basement membrane. This is the base on which the epithelium is formed, which then fits tightly to its walls. But it may also serve as a mechanism for epithelial migration.

This formation was first described by the German pathologist Rene Tuohimer Virchow (Tucher Kropfmuhl Freiherr von Wurzburg) in 1851. His surname can be translated as “headless horseman.” Considered the founder of pathological anatomy. A study published a few years later was entitled “The Foundation of Embryonic Tissues. Distribution of tissues around arteries with clarification of the classes of stromal tissues that form them." In subsequent years, later scientific research confirmed Virchow's leading role in this discovery. He described the anatomy of this capillary-like layer. In addition, he proposed that its structure explains the differences in epitheloid differentiation of different tissues and the way nerve fiber axons are distributed.

In the 1950s, American biologist Charles Scott Shillington conducted histochemical studies to identify serotonin and its major metabolites in the perivascular spaces through which microcirculation as a physiological process causes significant changes in tissues throughout the body. He proposed the term "perivascular space" as a general name for the interstitial space immediately adjacent to the vessels, but consisting of relatively concentrated cellular elements.

Although all layers of the interstitium are related by a common origin of endothelial cells, the perivascular region is a very specific layer. This specific layer increases thickness during the inflammatory process and thereby helps maintain the inflammatory process in the body.