Pericytes are multi-functional cells found wrapped around the endothelial cells lining capillaries and small venules throughout the body. They reside within the basement membrane of these microvessels and play crucial roles in regulating blood flow, maintaining the integrity of the blood-brain barrier, and participating in tissue repair and angiogenesis (the formation of new blood vessels). Think of them as supportive cells for the blood vessels' lining.
Pericyte Functions and Characteristics:
- Regulation of Blood Flow: Pericytes are contractile cells; they can constrict or dilate blood vessels, influencing blood flow in the microcirculation. This is especially significant in the brain, where pericytes help regulate cerebral blood flow. [Source: PubMed, PMC, Frontiers]
- Blood-Brain Barrier (BBB) Maintenance: They are essential for maintaining the integrity of the BBB, a crucial protective barrier in the central nervous system. [Source: Tempo Bioscience, Frontiers]
- Angiogenesis and Tissue Repair: Pericytes contribute to the formation of new blood vessels and participate in the healing process after tissue injury. [Source: Tempo Bioscience]
- Tumor Microenvironment: Pericytes have been identified as significant components within the tumor microenvironment (TME), influencing tumor growth and progression. [Source: Provided Reference]
- Mesenchymal Origin: Pericytes originate from mesenchymal cells. [Source: ScienceDirect]
Location and Structure:
Pericytes are situated between the endothelial cells of capillaries and the basement membrane. Their location allows them to interact closely with endothelial cells and influence vascular function. They are spatially isolated, meaning they are not continuously distributed along the vessel wall. [Source: PubMed, PMC]
Historically known as Rouget cells, pericytes are now recognized for their multifaceted roles beyond simply supporting the capillary structure. Their interaction with endothelial cells allows for precise control over microcirculation and tissue homeostasis. [Source: Wikipedia]
