A well-developed vascular system is crucial for the smooth functioning of the kidneys. Both harmful metabolic products and useful nutrients use the bloodstream to shuttle in and out of the organ. Consequently, a close interaction between the vessel system and the organ parenchyma is essential for the proper functioning of the kidney. To this end, clarity regarding the relationship between nephrogenesis and vessel development is lacking.

Micro-computed tomography (microCT) provides a means for obtaining a detailed three-dimensional description of the tissue structure and micro-vasculature in whole organs. In combination with the powerful techniques that are available for manipulation of experimental mice, this technique provides a means to address questions about the role of microvascular structure in disease and development.

Here, we present a technique of studying nephrogenesis and vessel development in vivo.

Figure 1: Mouse kidney scanned on the Scanco microCT 50 at 90kVp, 155uA, 300msec exposure (16.5micron voxel resolution) to study vasculature (in vitro).

Figure 2: Mouse kidney scanned on the Inveon CT at 80kVp, 200mA (16.5micron voxel resolution) to study vasculature (in vivo).

We use Exitron 12000, an alkaline earth metal-based nanoparticulate contrast agent (regions uptaking the contrast agent show strong X-ray absorption due to the high metal load of the particles), which circulates in the blood stream for a prolonged time period. Consequently, the blood vessels can be effectively visualized using our Siemens Inveon preclinical microCT scanner (in vivo) and our Scanco50 microCT scanner (in vitro).

High contrast images of the blood vessels in vivo and in vitro allow in-depth analysis of these volumes to precisely quantify the distributions of vessel diameter, vessel length, and branching angles for both arterial and venous vasculature. They also allow the evaluation of their feasibility as biomarkers for diagnosis and/or therapy of kidney related diseases.