Abstract P034: Vasculature Remodeling In Two Models Of Reduced Renal Mass

Abstract

Remnant kidney models of chronic kidney disease include the 1/3 nephrectomy (1/3Nx), and 5/6 nephrectomy rats. The 1/3Nx remnant kidney spontaneously atrophies with time, and the 5/6Nx hypertrophies. This disparate remodeling must occur with commensurate vascular changes, examination of which may reveal important molecular pathways and mechanisms underlying changes in renal function. The first step toward realizing this, and the aim of this study, was to characterize the renal vasculature from 1/3Nx, 5/6Nx, and sham Nx rats. Methods: The vasculature was examined in rats 10 weeks following surgery. To-date, these renal vasculatures have been quantified by (1) assessment of vascular density by analysis of bisected, renal vascular casts, and (2) renal blood flow doppler ultrasound. Data: Avg±SEM. Results: 1/3Nx remnant kidney atrophied and 5/6Nx hypertrophied (cross-sectional area: sham n=9; 241±7. 5/6Nx, n=9; 247±8. 1/3Nx, n=12; 132±11: mm 2 ). Despite this, kidney height (intact kidney long axis) to width (short axis) ratio was similar between the remnant models (5/6Nx; 0.8±0.04. 1/3Nx; 0.9±0.04). Sham kidney vascular density was significantly greater than that of 1/3Nx remnant kidneys, which exceeded that of 5/6Nx rats. Cortex vascular density was significantly different between all groups (sham; 95±2%. 1/3Nx; 57±9%. 5/6Nx; 25±11%). The statistical mode of the arterial blood flow distribution was not different between the groups, but mode venous flow was (sham; 100±6. 1/3Nx; 118±9. 5/6Nx; 136±8. Relative units.). Homogeneity of flow was quantified by expressing flow-direction boundaries as a percent of flow area. Sham flow was significantly more homogenous (1.8±0.2) than 1/3Nx (3.7±0.5), and 5/6Nx rats (3.9±0.3). Conclusion: These data demonstrate changes in vascular anatomy and function in both remnant kidney models. Interrogation of anatomical changes and molecular pathways may reveal novel treatment approaches.