Despite initial recovery of GFR long-term renal functions deteriorate following short periods of unilateral ureteral obstruction.

Following release of short periods of unilateral ureteral obstruction (UUO), glomerular filtration rate (GFR) recovers by time. However, research in experimental animal models, has demonstrated the presence of ongoing element of renal interstitial fibrosis few weeks following UUO reversal. Interstitial fibrosis can cause deterioration in GFR and it is not known if it leads to an ongoing slow deterioration in other renal functions despite the apparent initial recovery post-reversal. To investigate this, rats underwent a 72-hour reversible UUO. Renal functions of the non-obstructed (NOK) and previously obstructed (POK) kidneys were measured one month, 4 months and 18 months post-reversal. GFR in the POK and NOK was similar up to 18 months post-reversal. However, there was an ongoing tubulointerstitial fibrosis and the degree of tubular atrophy and dilatation deteriorated by time. This was associated with an increase in urinary albumin leakage and alterations in renal injury markers, pro-inflammatory and pro-fibrotic cytokines and in p53, from 4 months onward despite the recovery in GFR. In conclusion, several aspects of renal functions continue to deteriorate following reversal of relatively short periods of UUO despite the initial recovery in GFR. This might stimulate further research in this area and might have clinical implications in terms of determining the best time for intervention following acute ureteral obstruction and long-term monitoring of these individuals.