Kidney oxygenation, perfusion and blood flow in people with and without type 1 diabetes

BACKGROUND: We used magnetic resonance imaging (MRI) to study kidney energetics in persons with and without type 1 diabetes (T1D). METHODS: In a cross-sectional study, 15 persons with T1D and albuminuria and 15 non-diabetic controls (CONs) underwent multiparametric MRI (3 Tesla Philips Scanner) to quantify renal cortical and medullary oxygenation (R(2)*, higher values correspond to higher deoxyhaemoglobin concentration), renal perfusion (arterial spin labelling) and renal artery blood flow (phase contrast). Analyses were adjusted for age, sex, systolic blood pressure, plasma haemoglobin, body mass index and estimated glomerular filtration rate (eGFR). RESULTS: Participants with T1D had a higher median (Q1; Q3) urine albumin creatinine ratio (UACR) than CONs [46 (21; 58) versus 4 (3; 6) mg/g; P < .0001] and a lower mean ± SD eGFR (73 ± 32 mL/min/1.73 m(2) versus 88 ± 15 mL/min/1.73 m(2); P = .12), although not significantly. Mean medullary R(2)* was lower in T1D (34 ± 6/s versus 38 ± 5/s; P < .01) corresponding to a higher oxygenation. R(2)* was not different in the cortex. Cortical perfusion was lower in T1D (163 ± 40 versus 224 ± 49 mL/100 g/min; P < .001). Renal artery blood flow was lower in T1D than in CONs (360 ± 130 versus 430 ± 113 mL/min; P = .05). In T1D, lower cortical oxygenation and renal artery blood flow were both associated with higher UACR and lower eGFR (P < .05). CONCLUSIONS: Participants with T1D and albuminuria exhibited higher medullary oxygenation than CONs, despite lower cortical perfusion and renal artery blood flow. This might reflect perturbed kidney energetics leading to a higher setpoint of medullary oxygenation in T1D. Lower cortical oxygenation and renal artery blood flow were associated with higher UACR and lower eGFR in T1D.