Interstitium

The **interstitium** is a contiguous, dynamic fluid-filled compartment and support structure that exists between cellular barriers (such as cell membranes or the skin) and the internal tissues of organs. It consists of **interstitial fluid**, connective tissue matrix (including collagen, elastin, and glycosaminoglycans), and a variety of embedded cells (e.g., fibroblasts, immune cells). The interstitium serves critical roles in transporting nutrients, signaling molecules, and waste products; it also supports immune function and provides shock absorption for organs subjected to movement and external stress. Structural and chemical properties of the interstitium may change in health, inflammation, fibrosis, cancer, or other disease states. The interstitium is not a molecular entity or canonical therapeutic target but is increasingly recognized as important in disease mechanisms, particularly for facilitating immune cell and cancer cell trafficking and influencing pathological fluid accumulation[1][2][3][4][7][10].

Other names

Interstitial tissueinterstitial spaceinterstitial compartmentconnective tissue spaces