Abstract

Hypothesis

Definitions

Flow-induced remodeling differs in resistance and elastic arteries

Why study flow-induced arterial remodeling of resistance arteries?

Conclusion

Discussion
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Compensatory arterial structural changes in response to altered hemodynamics restore normal levels of circumferential wall stress (CWS) and wall shear stress (WSS). Failure of this remodeling may perpetuate arterial injury and promote arterial disease. We compared two recently introduced experimental animal models of 'flow-induced' arterial remodeling: parallel rat mesenteric arteries and parallel mouse carotid arteries exposed to elevated (+70 to 100%) or reduced (-80 to 100%) mean arterial blood flow, which are not and are accompanied by neointima formation, respectively (Am. J. Physiol. 273:H1699-H1709, 1997; Arteriosc. Thromb. Vasc. Biol. 17:2238-2244, 1997). Arterial diameter and media structure were evaluated by in vitro pressure-volume curves and morphometry on cross sections of fixed vessels, respectively. Changes with respect to sham-operated controls can be summarized as follows: (HF = elevated blood flow; lf = reduced blood flow; +++ = increase, --- = decrease) rat mes/HF rat mes/lf mouse car/HF mouse car/lf outer diameter +++ --- no change --- lumen diameter +++ --- no change --- media CSA +++ --- no change +++ neointima no no no yes Calculated CWS and WSS were normalized within 4 weeks time in both HF and lf rat mesenteric vessels. Thus, while structural responses to elevated and reduced blood flow are compensatory in nature in the muscular rat mesenteric arteries, they are mal-adaptive in the elastic carotid artery of mice (this study) and rats (earlier work). In view of this it may be worthwhile to address the role in arterial remodeling of factors that are unevenly distributed over the arterial tree, such as pulsatile hemodynamics, the extracellular matrix components collagen and elastin, and the cytoskeletal components vimentin and desmin. To some extent transgenic mouse models may be helpful in this respect.

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Presentation Number SAde mey0657
Keywords: remodeling, mouse, wall stress, shear stress, wall structure