Kocatürk H. et al., 2019: Evaluation of the urinary podocalyxin and nephrin excretion levels to determine a safe time interval between two sessions of SWL for renal stones: a non randomized exploratory study
Kocatürk H, Atasoy N, Bedir F, Karabulut İ, Şebin E, Sarica K.
Department of Urology, Health Sciences University, Erzurum Regional Training and Research Hospital, Palandöken, Erzurum, Turkey.
Department of Urology, Health Sciences University, Erzurum Regional Training and Research Hospital, Palandöken, Erzurum, Turkey.
Department of Biochemistry, Health Sciences University, Erzurum Regional Training and Research Hospital, Erzurum, Turkey.
Department of Urology, Faculty of Medicine, Biruni University, Istanbul, Turkey.
Abstract
OBJECTIVES: We aimed to evaluate the role of nephrin and podocalyxin in determining the intervals between shock wave lithotripsy (SWL) sessions and how soon the kidney damage was recovered. METHODS: This work was a prospective study that included 30 patients with unilateral kidney stones. The patients' midflow urine samples were collected before SWL and 1 h, 1 day and 1 week after the procedure. Nephrin and podocalyxin levels in the urine samples were measured by the enzyme-linked immunosorbent assay method .RESULTS: Among the 30 patients who underwent SWL, 19 were males and 11 were females. The mean age of the SWL group was 34.7 ± 13.2. Both biomarkers did not correlate with age, creatinine values, body mass index, stone side, stone size, energy, frequency and shock numbers. Nephrin and podocalyxin levels were significantly higher at the pre-SWL point (p < 0.05). After the procedure, a significant decrease was observed in both biomarker levels (p < 0.05). At the end of first day, these levels started to increase progressively up to the end of the first week (p > 0.05). CONCLUSIONS: Nephrin and podocalyxin may help to determine early period kidney damage associated with SWL. Post-SWL podocalyxin and nephrin values may be used to determine the interval between SWL sessions.
Int Urol Nephrol. 2019 Oct;51(10):1727-1734. doi: 10.1007/s11255-019-02229-8. Epub 2019 Jul 18.
Comments 1
A number of variables analysed in urine have been shown to reflect how the kidney is affected by shock wave power. In this article nephrin and podocalyxin have been studied and added to this list.
The authors aimed at a method that made it possible to determine how frequently SWL can be repeated. The two urine variables have their origin in glomeruli and their excretion returned to pre-treatment levels after one week. The conclusion was that this was an interval after which SWL safely can be repeated.
Whether this conclusion is correct and/or practically useful remains to be demonstrated. The number of patients included in this study is small (n=30), the range of variation pronounced and both nephrin and podocalyxin are expressed in concentrations rather than total amounts excreted. Urine volumes are not reported and the urine flow after SWL for various reasons can vary considerably. Moreover, it is my assumption that none of these variables easily can be analysed on a routine basis. In addition SWL may cause contusions that not only affects glomeruli, but a number of other structures in the renal tissue.
It is possible that the authors have drawn correct conclusions from their measurements, but from these results it is not possible to recommend one week as a safe interval between repeated SWL sessions.