Structural remodeling of mouse gracilis artery after chronic alteration in blood supply

Abstract

The goals of this study were to determine the time course and spatial dependence of structural diameter changes in the mouse gracilis artery after a redistribution of blood flow and to compare the observations with predictions of computational models for structural adaptation. Diameters were measured 1, 2, 7, 14, 21, 28, and 56 days after resection of one of the two blood supplies to the artery. Overall average diameter, normalized with respect to diameters in untreated vessels, increased slightly during the first 7 days, then increased more rapidly, reaching a peak around day 21, and then decreased. This transient increase in diameter was spatially nonuniform, being largest toward the point of resection. A previously developed theoretical model, in which diameter varies in response to stimuli derived from local metabolic and hemodynamic conditions, was extended to include effects of time-delayed remodeling stimuli in regions of reduced perfusion. Predictions of this model were consistent with observed diameter changes, including the transient increase in diameters near the point of resection, when a remodeling stimulus with a time delay of approximately 7 days was included. The results suggest that delayed stimuli significantly influence the dynamic characteristics of vascular remodeling resulting from reduced blood supply.

Impact of Mouse Strain Differences in Innate Hindlimb Collateral Vasculature

“…muscular side branches from many of these vessels, eg, on the surface of the gracilis muscle. 9,20 If these pre-existent interarterial connections are not large or not numerous enough, the intravascular pressure loss transmitted from their distal anastomoses after arterial occlusion apparently can result in an insufficient perfusion pressure for the surrounding muscle tissue.…”

Suppressed hindlimb perfusion in Rac2−/− and Nox2−/− mice does not result from impaired collateral growth

“…While many previous studies have compared the diameters of specific vessels in the mouse hindlimb to assess collateral growth (13,14,32,53,55,56,76), the method presented in this study provides a number of advantages. Controlled perfusion fixation with dilator preserves the vasculature in a consistent state.…”

“…1A. The gracilis collateral pathway has been previously described (15,16,32,33,44,56) and involves the gracilis artery, which originates from the profunda femoral (muscular branch) artery and passes through the superficial anterior and posterior gra- cilis muscles and reinserts into the distal saphenous artery. The deep adductor pathway originates as a branch of the internal iliac artery, passes along the ventral portion of the pelvis, and then penetrates the deeper adductor musculature to reinsert into the saphenous artery proximal to the reinsertion point of the gracilis collateral pathway.…”

Computational hemodynamic optimization predicts dominant aortic arch selection is driven by embryonic outflow tract orientation in the chick embryo

“…The two-element objective vector consisted of the total power to sustain blood flow (P T ) and the total diffusive exchange capacity (J) of the arch domain. Minimization of energy is an established principle of vascular form (Gruionu et al 2005;Kassab and Fung 1995;LaBarbera 1990;Murray 1926;Pries et al 1995;Sherman 1981;Taber 1998b;Zamir 1977), while maximizing diffusive capacity is derived from the homology of the aortic arches in lower order vertebrates where terminal arch pairs are the precursor of gill vasculature (see section 4.4 of the "Discussion").…”

“…An alternative approach is to employ an optimization-based growth strategy to model vessel growth in complex cardiovascular morphologies in response to secondary anatomical alterations and sustained flow and pressure perturbations. Theoretical (Sherman 1981;Taber 1998b;Zamir 1977) and experimental (Gruionu et al 2005;Kassab and Fung 1995;LaBarbera 1990) studies have provided strong evidence that vascular morphology is governed by a set of physiological principles that tend to optimize cardiovascular performance. The most widely regarded is Murray's law, which states that minimization of the total energy to drive blood flow and maintain the metabolic cost of blood volume determines vascular morphology (Murray 1926).…”