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Abstract: SA-PO081

Mapping Compensatory Renal Hypertrophy and Hyperfiltration in Living Kidney Donors Using Multiparametric Magnetic Resonance Imaging

Session Information

Category: Transplantation

  • 1802 Transplantation: Clinical

Authors

  • Li, Anna S., University of Manchester, Manchester, United Kingdom
  • Naish, Josephine H., University of Manchester, Manchester, United Kingdom
  • Gough, Matthew James, University of Manchester, Manchester, United Kingdom
  • Hamilton, Patrick, University of Manchester, Manchester, United Kingdom
  • Brenchley, Paul E., University of Manchester, Manchester, United Kingdom
  • Lennon, Rachel, University of Manchester, Manchester, United Kingdom
  • Hutchison, Alastair J., University of Manchester, Manchester, United Kingdom
Background

Despite sustained glomerular hypertrophy and hyperfiltration, the vast majority of living donors do not develop hyperfiltration injury with fibrosis and progressive GFR decline. Our study uses serial multiparametric MRI to assess volume and blood flow of the remaining kidney in the first month post-donor nephrectomy. Relationships between changes in kidney volume, renal blood flow (RBF) and single kidney GFR (SKGFR) may reflect functional reserve of the remaining kidney and provide insight into the early stages of nephron loss in the development of CKD.

Methods

6 living kidney donors underwent 3 sessions of MRI and creatinine-based eGFR measurements prior to, 4 days after, and 4 weeks after nephrectomy. The non-contrast multiparametric MR protocol includes: whole kidney volumetric assessment by manual delineation using a multi-slice T1-weighted (inversion-recovery) turbo-spin echo; assessment of RBF using a FAIR arterial spin labelling (FAIR-ASL) technique; and quantitative T1-mapping using a MOLLI technique.

Results

Median age of the donors was 57 (35 to 67); baseline kidney volume was 141±21mL, increasing to 183±38mL at day 4 and 179±32mL at week 4. SKGFR was 46±5mL/min at baseline, increasing to 61±12mL/min at day 4 and 60±9mL/min at week 4. RBF per unit weight did not change significantly at either day 4 (5.7±0.8 mL/g/min) or week 4 (6.4±0.4mL/g/min) from baseline (5.8±1.6mL/g/min). T1 value of the renal cortex saw a small increase at day 4 (1.64s) compared to baseline (1.53s), which is maintained at week 4 (1.62s).

Conclusion

The results show that compensatory hypertrophy and hyperfiltration started rapidly following renal tissue loss, became established within a few days, and sustained over the next 3-4 weeks. Given adult glomerular number does not increase in compensatory hypertrophy, our preliminary findings indicate that average single glomerular volume and GFR rose post-donation. As RBF per unit weight did not change post-nephrectomy in our cohort, with glomerular hypertrophy, this suggests that overall single glomerular blood flow would also increase. Further study into this growth of normal tissue is required to identify imaging biomarkers for nephron reserve and capacity for compensation before the onset of hyperfiltration injury.

Funding

  • Commercial Support