Figure 1.

RO₂:GFR and relative renal hypoxia. The top panel illustrates the relationship between RO₂ and GFR. A high GFR (workload) requires a high kidney oxygen availability to sustain the high energy expenditure. Therefore, whole-kidney hyperfiltration (HF) requires higher kidney oxygen availability compared with normofiltration (NF) and underfiltration (UF). The height of the smokestack plumes represents the magnitude of GFR. The bottom panel illustrates the ratio between RO₂ and GFR across UF, NF, and HF. Additionally, the bottom figure demonstrates three energetic scenarios across the stages of DKD: relative hyperoxia (RO₂ > GFR), balance (RO₂ = GFR), and relative hypoxia (RO₂ < GFR).