Glomerular hyperfiltration after unilateral nephrectomy in living kidney donors

Abstract

Glomerular hyperfiltration, which is expected to occur after uninephrectomy, could potentially damage the non-transplanted donor kidney in living donor transplantation. We therefore prospectively measured renal function (inulin and PAH clearance), albumin excretion and blood pressure in the donors of 30 consecutive living donor kidney transplants before uninephrectomy (n = 29) and 1 week (n = 27) and 1 year (n = 16) after. Hyperfiltration was defined as: (post-nephrectomy inulin clearance )/(0.5 x pre-nephrectomy inulin clearance); hyperperfusion was defined in an analogous way for PAH clearance. Hyperfiltration averaged 128 ± 5% [SEM] and hyperperfusion 133 ± 6% 1 week after uninephrectomy. Hyperfiltration was nearly unchanged (126 ± 7%) 1 year after nephrectomy, whereas hyperperfusion had significantlydecreased to 118 ± 8% (P < 0.02). There was no significant change in blood pressure after nephrectomy, and no new cases of hypertension were observed during the 1-year follow-up. The degree of hyperfiltration did not correlate with donor age. Microalbuminuria > 30 mg/24 h was found in two donors 1 week after nephrectomy (one of which normalized at 1 year) and in one additional donor 1 year after nephrectomy. The degree of hyperfiltration did not correlate with albumin excretion rate. In conclusion, no adverse consequences of hyperfiltration were demonstrable during the 1-year observation period, but the prognostic role of occasional microalbuminuria should be further investigated.An increased glomerular filtration rate, also termed 'hyperfiltration' is considered an important factor in the pathogenesis of various nephropathies and in the non-immunological progression of chronic renal failure [4]. The paradigmatic example for this is the hyperfiltration which Offprint requests to:

Renal autoregulation: new perspectives regarding the protective and regulatory roles of the underlying mechanisms

“…Clearly, chronic alterations in GFR and RBF occur in response to metabolic and excretory needs. Examples include the hyperfiltration observed with protein feeding (90) and uninephrectomy (19,24) and in pregnancy (11). Evidence implicates a chronic resetting of TGF in such settings and in the hyperfiltration seen in diabetes (141,158).…”

Long-Term Consequences of Uninephrectomy in Male and Female Rats

“…5,6 Some researchers have found an increase in BP after kidney donation, 7,8 and studies comparing donors with siblings or potential kidney donors have shown conflicting results for the impact of donation on BP, renal function, and proteinuria. 7,[9][10][11][12] It is complicated to dissociate the effects of the aging process from the influence of UNX, because both renal function and BP are influenced by age. Thus, in studies of ageand sex-matched populations, some 9,11,12 but not all 7 authors found differences in BP between kidney donors and the general population.…”

“…7,[9][10][11][12] It is complicated to dissociate the effects of the aging process from the influence of UNX, because both renal function and BP are influenced by age. Thus, in studies of ageand sex-matched populations, some 9,11,12 but not all 7 authors found differences in BP between kidney donors and the general population. Rats undergoing UNX at 3 weeks of age were reported to show hypertension and reduced glomerular filtration rate at 6 to 8 weeks in comparison with controls, 13 and Zheng et al 14 performed UNX in mice and found a more advanced diabetic nephropathy in diabetic mice but almost no effects in nondiabetic mice.…”

Evaluation of Kidney Function and Structure in Potential Living Kidney Donors: Implications for the Donor and Recipient

“…Velosa et al among others showed that as early as 1-week post-nephrectomy, renal function has recovered to levels slightly lower than those achieved at 6 months post-nephrectomy. Similarly, others have shown that the GFR at 1-year post-donation is similar to the one achieved within a week of nephrectomy [16,21].…”