intussusceptiivinen

Intussusceptiivinen is a Finnish adjective used in biology and medicine to describe processes that involve inward folding or insertion of tissue, structures, or membranes. In practice the term is most often applied to intussusceptive angiogenesis, a mode of blood vessel formation where new vessels arise by internal partitioning of existing ones rather than by sprouting from new tips.

Intussusceptive angiogenesis differs from sprouting angiogenesis in that it relies on the formation of transvascular pillars or tissue bridges that extend into the lumen of a vessel. These pillars subdivide a capillary into daughter vessels, allowing rapid expansion of the microvascular network with relatively modest endothelial proliferation. The process can proceed through steps such as contact and fusion of opposing endothelial walls, pillar formation, pillar elongation, and remodeling of the vessel wall.

The term is used primarily in vascular biology, developmental biology, and pathology. It is important to distinguish intussusceptive processes from intestinal intussusception, a pathological telescoping of a segment of intestine into another, which is a different phenomenon entirely.

Intussusceptive mechanisms occur in various contexts, including embryonic development, organ remodeling, wound healing, and tumor-associated angiogenesis. They are observed in multiple species and tissues, such as the placenta, lungs, retina, and tumor vasculature. Understanding intussusceptive angiogenesis has implications for therapeutics aimed at promoting or inhibiting vascular growth, depending on clinical needs.

See also: angiogenesis, sprouting angiogenesis, vascular remodeling, intussusception (medical condition).