A whole-organ multi-scale in silico framework for human kidney haemodynamics informed by hierarchical phase-contrast tomography

Studying human kidney haemodynamics has been limited by the absence of complete vascular maps of the whole organ. Here we utilise previously generated multi-resolution hierarchical phase-contrast tomography (HiP-CT) coupled with a hybrid anatomically-grounded synthetic reconstruction to generate a full arterial-glomerular network of an intact human kidney comprising 1.6 million vessels and over 800,000 glomeruli. Using this anatomically comprehensive structure, we apply physics-based zero-dimensional haemodynamic modelling to quantify blood pressure, flow and simulated filtration rate across the entire organ. We show that the reconstructed human kidney vascular network exhibits order-dependent branching behaviour similar to that of rat kidneys, and that physiologically plausible pressure and flow patterns are recovered only when the full vascular network is represented. We further demonstrate how the kidney responds to macrovascular and microvascular perturbations, including stenosis of the large renal arteries and narrowing or ablation of afferent arterioles. Stenosis and arteriole narrowing exhibit threshold-type behaviour, with kidney perfusion and simulated glomerular filtration rate remaining largely preserved up to [~]50% narrowing, followed by sharp nonlinear declines beyond [~]70%. These predictions emerge in the absence of autoregulatory mechanisms, indicating that vascular geometry and resistance scaling alone contribute to kidney functional deterioration. Together, our framework provides the first organ-wide, data-driven model of human kidney haemodynamics and offers a foundation for future studies of kidney physiology and disease.