intravasatie

Intravasatie, or intravasation in English, is the process by which substances or cells cross into the vascular or lymphatic system from neighboring tissue. It is a term used in physiology, pathology, and oncology to describe entry into the bloodstream or lymphatics.

In cancer biology, intravasation is a critical step in the metastatic cascade. Tumor cells must breach the endothelial lining and basement membrane of blood or lymphatic vessels to disseminate to distant sites. This involves multiple interacting factors: degradation of extracellular matrix by proteases such as matrix metalloproteinases, remodeling of adhesion molecules, endothelial cell retraction or opening of vascular gaps, and tumor cell–platelet interactions that protect tumor cells in circulation. The process is influenced by the tumor microenvironment, including perivascular macrophages, fibroblasts, and chemokine signals (for example CXCL12–CXCR4).

Intravasation is thought to be a rate-limiting step in metastasis, and its efficiency affects metastatic potential. Circulating tumor cells provide evidence of intravasation; molecular imaging and microfluidic studies seek to quantify it.

Outside oncology, intravasation can refer to the entry of intravenously delivered substances into small vessels, or more broadly to any event where material enters the bloodstream or lymphatics. The more commonly used term for leakage from vessels into surrounding tissue is extravasation.

Clinical relevance: Researchers investigate therapies that impair intravasation by targeting the endothelium, proteases, or signaling pathways that promote vascular invasion. Understanding intravasation helps explain patterns of metastasis and informs the development of anti-metastatic strategies.