Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
Board

This study was designed to characterize structural remodeling of male Wistar rat mesenteric arteries exposed to elevated blood flow in vivo for 1, 3, or 7 days. A series of arterial ligations induced blood flow elevations in ileal and second-order branch arteries compared to same animal control vessels while maintaining normal mean arterial pressures. The primary flow-mediated force in both vessels was shear stress with possible involvement of acute stretch-induced wall stress in the ileal artery. Significant lumen expansion and medial wall hypertrophy concomitant with increases in extracellular connective tissue occurred in the high flow arteries in a time-dependent fashion. Wall thickness:lumen diameter ratios did not change in any vessel at any time, suggesting normalization of flow-induced wall stress occurs through vascular remodeling. Immunostaining for proliferating cell nuclear antigen and nuclear profile analyses indicate medial SMC and intimal EC hyperplasia contributed to flow-induced remodeling of the vessel wall. Endothelial NOS immunoreactivity was detected in the high flow vessels at all time points. Results from in situ hybridization revealed significantly elevated PDGF-A mRNA expression in the media after 24 hours and in the endothelium after 3 and 7 days in the high flow vessels. The findings from this study suggest flow-stimulated arterial remodeling in vivo involves SMC and EC hyperplasia and increases in extracellular connective tissue. This vessel wall restructuring may involve the actions of NO and PDGF-A as regulators of flow-stimulated growth.

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Presentation Number SAtulis0444
Keywords: shear stress, hoop stress, vessel remodeling, growth factor, mesenteric artery