TY - JOUR
T1 - Blood Vessel Adaptation with Fluctuations in Capillary Flow Distribution
AU - Hu, Dan
AU - Cai, David
AU - Rangan, Aaditya V.
PY - 2012/9/27
Y1 - 2012/9/27
N2 - Throughout the life of animals and human beings, blood vessel systems are continuously adapting their structures - the diameter of vessel lumina, the thickness of vessel walls, and the number of micro-vessels - to meet the changing metabolic demand of the tissue. The competition between an ever decreasing tendency of luminal diameters and an increasing stimulus from the wall shear stress plays a key role in the adaptation of luminal diameters. However, it has been shown in previous studies that the adaptation dynamics based only on these two effects is unstable. In this work, we propose a minimal adaptation model of vessel luminal diameters, in which we take into account the effects of metabolic flow regulation in addition to wall shear stresses and the decreasing tendency of luminal diameters. In particular, we study the role, in the adaptation process, of fluctuations in capillary flow distribution which is an important means of metabolic flow regulation. The fluctuation in the flow of a capillary group is idealized as a switch between two states, i.e., an open-state and a close-state. Using this model, we show that the adaptation of blood vessel system driven by wall shear stress can be efficiently stabilized when the open time ratio responds sensitively to capillary flows. As micro-vessel rarefaction is observed in our simulations with a uniformly decreased open time ratio of capillary flows, our results point to a possible origin of micro-vessel rarefaction, which is believed to induce hypertension.
AB - Throughout the life of animals and human beings, blood vessel systems are continuously adapting their structures - the diameter of vessel lumina, the thickness of vessel walls, and the number of micro-vessels - to meet the changing metabolic demand of the tissue. The competition between an ever decreasing tendency of luminal diameters and an increasing stimulus from the wall shear stress plays a key role in the adaptation of luminal diameters. However, it has been shown in previous studies that the adaptation dynamics based only on these two effects is unstable. In this work, we propose a minimal adaptation model of vessel luminal diameters, in which we take into account the effects of metabolic flow regulation in addition to wall shear stresses and the decreasing tendency of luminal diameters. In particular, we study the role, in the adaptation process, of fluctuations in capillary flow distribution which is an important means of metabolic flow regulation. The fluctuation in the flow of a capillary group is idealized as a switch between two states, i.e., an open-state and a close-state. Using this model, we show that the adaptation of blood vessel system driven by wall shear stress can be efficiently stabilized when the open time ratio responds sensitively to capillary flows. As micro-vessel rarefaction is observed in our simulations with a uniformly decreased open time ratio of capillary flows, our results point to a possible origin of micro-vessel rarefaction, which is believed to induce hypertension.
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U2 - 10.1371/journal.pone.0045444
DO - 10.1371/journal.pone.0045444
M3 - Article
C2 - 23029014
AN - SCOPUS:84866929230
SN - 1932-6203
VL - 7
JO - PloS one
JF - PloS one
IS - 9
M1 - e45444
ER -