Spring 2018 – Testing Predictions of Adaptation of Microvascular Networks

Systemic blood pressure and regional tissue perfusion are determined by the radii of micro-vessels. Adaptation of microvascular radii is inherently complex, because each vessel responds to local mechanical stimuli, and yet all the micro-vessels in a network appear to adapt their radii in a coordinated manner to ensure blood supply matches tissue demand. We propose a novel mechanism for adaptation that does not assume non-physiological “set points” that define equilibrium endothelial shear stresses, blood pressures and flows, but instead predicts these hemodynamic variables from physiological “balance points”. To test model predictions of proposed adaptive responses, it is  necessary to measure relevant microvascular radii and hemodynamic variables both before and after disturbing blood flow to tissue by occluding select micro-vessels. Given the ability to track changes in the microvasculature over time, we will use the chick chorioallantoic membrane (CAM) model. First, the architecture of several branches of the microvasculature network will be mapped.  A simple mathematical model will then be developed to predict changes in blood flow and radii of the network with select occlusions. Following this, vessels will be occluded, and the resulting radii of the microvascular network will be compared to model results.