Maturation of malfunctioning kidneys.

Because loss of functional renal mass is compensated by hyperfiltration of remaining tissue, one could hypothesize that a damaged kidney might not have the same rate of maturation as the contralateral one. To verify this, maturation was evaluated in children with asymmetrical renal function during early life. Twenty-five children were selected having had 2 (99m)Tc-MAG3 renograms combined with (51)Cr-EDTA clearance measurement, enabling estimation of glomerular filtration rate (GFR), split renal function (SRF), and single kidney GFR (SKGFR). The first test had to be performed before the age of 18 months and SRF on the affected side had to be < or =40%. Moreover, GFR had to increase between the 2 tests by > or =10 mL(-1) min/1.73 m(2), reflecting maturation due to age. For 18 children SRF changed by between -5% and +5%. For 4 children an increase of > or =5% was observed whereas for the remaining 3 a decrease of > or =5% occurred. For the first 22 kidneys, mean increase of SKGFR was +6.3 mL(-1) min/1.73 m(2)(SD: 6). For the 3 kidneys with > or =5% SRF decrease, SKGFR remained unchanged in 2 (+0.3 and -3 mL min(-1)/1.73 m(2)) and increased in the third patient (+15 mL min(-1)/1.73 m(2)). In conclusion, renal maturation is comparable in both the malfunctioning kidney and the contralateral normal functioning side.