Computational flow dynamics in a geometric model of intussusceptive angiogenesis.

Intussusceptive angiogenesis is a process that forms new blood vessels by the intraluminal division of a single blood vessel into two lumens. Referred to as nonsprouting or intussusceptive angiogenesis, this angiogenic process has been described in morphogenesis and chronic inflammation. Mechanical forces are relevant to the structural changes associated with intussusceptive angiogenesis because of the growing evidence that physiologic forces influence gene transcription. To provide a detailed analysis of the spatial distribution of physiologic shear stresses, we developed a 3D finite element model of the intraluminal intussusceptive pillar. Based on geometries observed in adult intussusceptive angiogenesis, physiologic shear stress distribution was studied at pillar sizes ranging from 1 to 10 microm. The wall shear stress calculations demonstrated a marked spatial dependence with discrete regions of high shear stress on the intraluminal pillar and lateral vessel wall. Furthermore, the intussusceptive pillar created a "dead zone" of low wall shear stress between the pillar and vessel bifurcation apex. We conclude that the intraluminal flow fields demonstrate sufficient spatial resolution and dynamic range to participate in the regulation of intussusceptive angiogenesis.