1. Bone and Mineral Metabolism and Fibroblast Growth Factor 23 Leves After Kidney Donation Gustavo Fernandes Ferreira, Giselle Guerra, Eva Schiavenato, Fabina Agena, Rosa Maria Affosno Moyses, Elias David-Neto, Myles Wolf
Renal Transplant Service, Hospital das Clinicas, University of Sao Paulo School of Medicine, Sao Paulo, Brazil;
Division of Nephrology, Department of Medicine, University of Miami, Miami.
Study Design
Introduction: Living kidney donors (LKDs) experience an abrupt decline in glomerular filtration rate (GFR). Mineral metabolism adaptations in early CKD are still debated and not well studied in LKDs. We prospectively studied acute and long term mineral metabolism adaptation of LKDs.
Materials and Methods: We measured renal function and mineral metabolites longitudinally for 1 year (days (D) 1, 2, 14, 180, & 365 post-operatively) in 74 healthy individuals who underwent kidney live donation.
FGF 23
Creatinine
MDRD
PTH
Serum Ca
Serum P
FE Phosphate
FGF 23
Creatinine
MDRD
PTH
Serum Ca
Serum P
FE Phosphate
FGF 23
Creatinine
MDRD
PTH
Serum Ca
Serum P
FE Phosphate
FGF 23
Creatinine
MDRD
PTH
Serum Ca
Serum P
FE Phosphate
FGF 23
Creatinine
MDRD
PTH
Serum Ca
Serum P *
Pre-transplant
Study
D-1 D1 D2
D14
D180
D360
Nephrectomy * * *
Results: eGFR (MDRD) decreased to 59% of its baseline on day 2 and started to increase at day 3. to its maximum at day 360 (75.3±15.6 ml/min/1.73m2. p<0.01) wile FGF23 increased from 60.6 (25th-75th percentile RU/mL) at baseline to 111.0±144.6 (p<0.01) on day 1 and keep higher than baseline throwout the study. PTH rose maximally on day 1 (64.9 ± 30.3pg/ml) and returned to its base line on D2 and did not change after that. Total serum Calcium levels decreased from 9.40±0.48 mg/dL to a nadir of 7.99±0.51 mg/dL on day 1 (p<0.001). Serum Phosphate levels reached their nadir on day 2 (2.61±0.52 mg/dL; p<0.01). At D14 total calcium and phosphate levels had returned to baseline. but phosphate levels returned down on D360 (3.36±0.52 mg/dL; p<0.001). Phosphate excretion fraction (FePO4) increased from base line (11.4±5.2%) up to 15.2±8.1% until D360 (p<0.001). * * * * * * **
-1 Day
1 Day
2 Days
14 Days
6 Months
1 Months
ANOV A
GFR(ml/min/1.73m2)
109.521.3
67.916.3***
65.713.1***
71.514.9***
74.615.7***
75.315.6***
<0.001
Creatinine (mg/dL)
0.810.14
1.240.24***
1.270.67***
1.180.22***
1.140.22***
1.13 0.22***
Calcium (mg/dL)
9.40.48
7.90.51***
8.30.4***
9.40.4
9.40.5
9.30.4
Phosphate(mg/dL)
3.700.5
3.370.6***
2.610.5***
3.710.5
3.500.6
3.360.5***
PTH (pg/ml)
44.414.7
64.930.3***
50.021.0
39.915.3
49.520.6
52.422.2
ln FGF23
3.720.88
3.941.28*
3.531.26
3.960.96*
3.910.89**
3.930.76
FE Phosphate(%)
11.45.2 NA
14.74*
17.89.1***
15.28.1** *
*P<0.05; **p<0.01; ***p<0.001 * *
Conclusions: Abrupt reduction in eGFR induces physiological increases in FGF23 and PTH. and decreases in serum Ca and Pi in the first week. The changes in FGF23 and Pi urinary fractional excretion of Pi remain modestly yet significantly different from baseline throughout the first year after nephrectomy. Wile Ca. PTH and Pi serum levels are not significantly different from the baseline. * * *
Conflict of Interest:
None of the authors has any potential financial conflict related to this work.