Kidney Week

Abstract: TH-PO915

Magnetic Resonance Imaging Biomarkers Independently Predict GFR and Urine Albumin Creatinine Ratio

Session Information

• Diabetic Kidney Disease: Biomarkers, Pathogenesis
  November 07, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Diabetic Kidney Disease

• 602 Diabetic Kidney Disease: Clinical

Authors

• Johansson, Lars, Antaros Medical AB, Molndal, Sweden

Lars Johansson,

• Hockings, Paul, Antaros Medical AB, Molndal, Sweden

Paul Hockings,

• Makvandi, Kianoush, Sahlgrenska University Hospital, Göteborg, Sweden

Kianoush Makvandi,

• Jensen, Gert, Sahlgrenska University Hospital, Göteborg, Sweden

Gert Jensen,

• Unnerstall, Tim, Sahlgrenska University Hospital, Göteborg, Sweden

Tim Unnerstall,

• Leonhardt, Henrik, Sahlgrenska University Hospital, Göteborg, Sweden

Henrik Leonhardt,

• Jarl, Lisa, Antaros Medical AB, Molndal, Sweden

Lisa Jarl,

• Englund, Camilla, Antaros Medical AB, Molndal, Sweden

Camilla Englund,

• Erlandsson, Fredrik, AstraZeneca, Gaithersburg, Maryland, United States

Fredrik Erlandsson,

• Sundgren, Anna K., AstraZeneca, Gaithersburg, Maryland, United States

Anna K. Sundgren,

• Hulthe, Johannes, Antaros Medical AB, Molndal, Sweden

Johannes Hulthe,

• Baid-Agrawal, Seema, Sahlgrenska University Hospital, Göteborg, Sweden

Seema Baid-Agrawal,

Background

Estimated GFR (eGFR) and urine albumin/creatinine ratio (UACR) are the standard methods for assessing glomerular damage and renal function changes in clinical practice, Within-person variations are large in people with diabetes due to the complex nature of diabetic kidney disease (DKD). New non-invasive markers are needed to increase understanding of disease pathogenesis. We recently showed that magnetic resonance imaging (MRI) markers correlated strongly to both measured GFR (mGFR) and UACR. Here we seek to determine which MRI markers are independent predictors of mGFR and UACR.

Methods

Subjects: The study included 2 CKD2, 16 CKD3, and 20 CKD4 subjects with DKD, 18-79 years old, and 20 age- and gender-matched healthy controls. GFR was measured using iohexol clearance. UACR was assessed in the first morning sample.
MRI techniques:
- Renal hemodynamics with mean arterial flow (ml/s)
- Renal microstructure, such as fibrosis and cellular infiltration, by measurement of Apparent Diffusion Coefficient (ADC) (mm²s^-1 x 10^-3) and R₁ (s^-1)
- Renal oxygenation by measurement of BOLD R₂* (s^-1)
- Renal macrostructure by kidney volume assessment (ml)
Statistics: We performed multiple regression analyses in the control group and the CKD group separately: 1) with UACR, mean arterial flow, R₁ cortex, R₂* cortex, ADC cortex, and kidney volume as independent variables, and mGFR as the dependant variable; and 2) with mGFR, mean arterial flow, R₁ cortex, R₂* cortex, ADC cortex, and kidney volume as independent variables, and UACR as the dependent variable.

Results

The only independent predictors of mGFR in the CKD group were mean arterial flow (p < 0.0001) and kidney volume (p = 0.03), with none in the control group. The only independent predictors of UACR were cortical R₁ in the CKD group (p = 0.005) and kidney volume in the control group (p = 0.01).

Conclusion

It is well known that GFR is strongly linked to renal blood flow and therefore not surprising to see mean arterial flow emerge as an independent predictor of mGFR. The strong link between cortical R₁ and UACR indicates that cortical R₁, a measure of cellular infiltration in the cortex where the filtration barrier exists, may be a novel biomarker of kidney damage and warrants further investigation.

Funding

• Commercial Support –