Renal function before and after unilateral nephrectomy in renal donors

Area of Science:

• Nephrology
• Renal Physiology
• Surgical Adaptation

Background:

• Unilateral nephrectomy, the removal of one kidney, prompts compensatory changes in the remaining kidney.
• Understanding the extent and nature of these functional adaptations is crucial for assessing renal reserve and donor outcomes.

Purpose of the Study:

• To quantify the functional adaptations of the remaining kidney after unilateral nephrectomy in healthy renal donors.
• To compare post-nephrectomy renal function with pre-nephrectomy values and 50% of baseline.

Main Methods:

• Measurements of glomerular filtration rate (GFR), effective renal plasma flow (ERPF), tubular maximum reabsorption of glucose (TmG), secretion of para-aminohippurate (TmAh), and clearances of inorganic phosphate (CP), uric acid (CU), urine diluting capacity (CH2O), and net acid excretion (UHA+V) were performed.
• These measurements were taken before and 10-14 days after unilateral nephrectomy in seven healthy renal donors.

Main Results:

• Mean post-nephrectomy GFR increased by 36% and mean ERPF by 55%.
• Significant increases were observed in TmG, TmAh, CP, CU, CH2O, and UHA+V.
• Increases in TmAh, TmG, and CH2O were proportional to GFR rise, while CP, CU, and UHA+V increased proportionally more than GFR.

Conclusions:

• The remaining kidney demonstrates substantial functional compensation following unilateral nephrectomy.
• Specific tubular functions adapt differently relative to the overall increase in GFR.
• Changes in renal handling of phosphate post-nephrectomy are not mediated by increased parathyroid hormone secretion.