Nephro-Neurovascular Interactions in the Human Kidney Using Light Sheet Fluorescence Microscopy

Background: Light sheet fluorescence microscopy (LSFM) is a powerful way to create large 3D tissue images and glean insights into kidney physiology. Here we developed imaging and analytical methods using LSFM on human kidneys to study the neurovascular connectivity of its functional tissue units (FTUs). Methods: We developed a pipeline from processing slices of human kidney lobes to clearing, image acquisition, image processing, and analysis with available and in-house coded software. Analytical pipelines included segmentation of FTUs and neurovasculature to study patterning of kidney nerves via the creation of neural networks (Fig 1) at macro, meso, and microscopic scales. Results: In addition to volumetric properties of organization, we report novel observations related to the patterns renal nerves establish between glomeruli and tubules. We define seven motifs of neuro-glomerular networks emanating from the renal vascular pole that organize glomeruli into communities. This includes the same nerve innervating multiple glomeruli together with nearby tubules, and/or the medullary ray, suggesting a neural feedback mechanism between communities of nephrons. Throughout the renal cortex, glomerular neural communities are interconnected through “mother glomeruli”. This organization likely permits FTUs to synchronize responses to perturbations in fluid homeostasis, utilizing mother glomeruli as network control centers. Mathematical modelling of this arrangement suggests that if a part of the network is damaged, the remaining FTUs can compensate till a threshold beyond which normal function deteriorates. Conclusion: We provide several novel contributions ranging from 3D analytical tools to discoveries that are paradigm shifting and transformational in relation to how 3D structural relationships and organization between kidney FTU and nerves may enable the kidney to adapt to hemodynamic alterations and maintain homeostasis. Funding: Other NIH Support - NIH Grant ID: U54DK134301