IL-6 does not predict current urolithiasis in stone formers

Evaluation and physiopathology of minor transient shock wave lithotripsy - induced renal injury based on urinary biomarkers levels

Introduction

Extracorporeal shock wave lithotripsy (ESWL) is one of the most useful methods available for the treatment of urolithiasis. However, despite its significant benefits, adverse effects can occur. Oxidative stress mediated by ischemia-reperfusion might contribute to kidney injury after ESWL. Moreover, an acute kidney injury (AKI) may develop. AKI is typically diagnosed by measuring serum creatinine level, yet serum creatinine does not allow for early detection of sub-clinical AKI. The latest report has investigated multiple ways to determine ESWL - induced renal damage through the evaluation of various urine biomarkers of renal injury.

Materials and methods

The Medline and Web of Science databases were searched without a time limit in November 2017 using the terms 'ESWL' in conjunction with 'kidney failure', 'kidney damage', 'renal injury' and 'inflammation markers', 'biomarkers'. Boolean operators (NOT, AND, OR) were also used in succession to narrow and broaden the search. In this review, we described all the up-to-date reported urine markers of ESWL-induced renal damage.

Results

In recent years, several studies demonstrated evaluation of ESWL - induced renal injury based on urinary biomarkers levels and its utility in clinical practice. They have a beneficial role in the early detection of AKI, as well as in observation of a transition of this acute illness into chronic kidney disease.

Conclusions

Different markers have been evaluated in the urine before and after the ESWL treatment, but their number is still limited and results remain inconclusive. Further investigations are mandatory.

Evaluating ESWL-induced renal injury based on urinary TNF-α, IL-1α, and IL-6 levels

Extracorporeal shockwave lithotripsy (ESWL) has dramatically changed the treatment of urinary lithiasis and has been the first treatment option for the majority of patients for more than two decades. Despite its significant benefits, it induces acute renal injury that extends from the papilla to the outer cortex. We evaluated the severity of the inflammatory response to ESWL by measuring the urinary excretion of the cytokines TNF-α, IL-1α, and IL-6. The study included 21 selected patients and 14 control subjects. All patients underwent the same ESWL procedure (2,500 shockwaves at 100 shockwaves/min and 0.039 J from the lithotripter). Urine TNF-α, IL-1α, and IL-6 levels were measured using standard ELISA kits. In the study population (patients and controls), we did not detect TNF-α in the urine samples. The levels of both IL-1α (2.5 pg/ml) and IL-6 (3.8 pg/ml) measured before ESWL were not significantly different from the control group (2.5 and 5.2 pg/ml, respectively; p > 0.05). Twenty-four hours after ESWL, in contrast to IL-1α (4 pg/ml), urine IL-6 (19.7 pg/ml) increased significantly (p < 0.05). Fourteen days after ESWL, IL-1α increased to 5 pg/ml, while IL-6 (7 pg/ml) decreased to the control level. Urine cytokine levels may be used to evaluate the inflammatory response to ESWL. After ESWL, IL-6 levels increased in the early phase, while IL-1α levels increased later. These two markers may be used to measure the severity of inflammation. In contrast to IL-1α and IL-6, urine TNF-α excretion was not increased by ESWL. We believe that the inflammatory response to ESWL can be detected by the urinary excretion of IL-1α for up to 14 days.