Evaluation of the impact of shock wave lithotripsy on kidneys using a new marker: how do neutrophil gelatinese-associated lypocalin values change after shock wave lithotripsy?

The Ideal Interval Between Repeated Shockwaves Lithotripsy Sessions for Renal Stones: A Randomized Controlled Trial

Objectives: To assess the ideal interval between repeated extracorporeal shockwave lithotripsy (SWL) for renal stones. Patient and Methods: Eligible patients with a single renal stone ≤20 mm who required SWL were randomly assigned to one of three groups based on intervals between first and second sessions. Patients underwent the second session after 3, 7, and 14 days in Groups 1, 2, and 3, respectively. Tubular functions were assessed through comparisons of urinary execration of kidney injury molecule-1 (KIM-1), neutrophil gelatinase associated lipocalin (NGAL), and interleukin-18 (IL-18) with pre-SWL values, whereas glomerular function was assessed by comparisons of protein/creatinine ratio with pre-SWL and changes in ipsilateral renal function on isotope scans. Treatment success was assessed by noncontrast CT after 3 months. Results: All demographics of the 166 patients included in the study were comparable between the three groups. There were significant elevations of tubular biomarkers and protein/creatinine ratio after first and second SWL sessions compared with pre-SWL values (p < 0.0001). All tubular biomarkers returned to pre-SWL values at 7 and 14 days after second session, whereas they remained significantly elevated 3 days after second session (p = 0.027, < 0.001 and <0.001 for KIM-1, NGAL, and IL-18, respectively). SWL success was 73.6% in Group 1, 83.7% in Group 2, and 81% in Group 3. A significant decrease in ipsilateral renal split function was observed in Group 1 at the 3-month follow-up. Conclusions: An interval of 7 days is required between SWL sessions when treating renal stones to allow for complete recovery of kidney functions. Clinical Trial Registration: ID: NCT04575480.

Urinary neutrophil gelatinase-associated lipocalin level as a biomarker of acute kidney injury following extracorporeal shock wave lithotripsy

Introduction

Although extracorporeal shock wave lithotripsy (ESWL) is minimally invasive and highly efficient for the management of kidney stones, adverse effects have been described. Available indicators of renal function exhibit insufficient sensitivity in acute renal injury (AKI). We aimed to evaluate the severity of the kidney tissue response to ESWL injury by measuring the urinary neutrophil gelatinase-associated lipocalin (uNGAL), which can indicate AKI in its early phase.

Material and methods

The prospective, controlled study included 62 patients with nephrolithiasis undergoing single ESWL treatment. uNGAL level was measured before the procedure, and 6 h and 12 h after.

Results

The median uNGAL level increased by 126.0%, 6 h after ESWL (p <0.001). The growth rate continued and 12 h after was higher by 583.7%, compared to the pre-treatment level (p <0.001). The median value of estimated glomerular filtration rate (eGFR) dropped by 15.3% 12 h after the treatment (p <0.001). It increased by 5.0% in the period 7 days to 3 months after (p <0.001) and after 3 months it was lower by 10.1% compared to pre-ESWL values (p <0.001). uNGAL level after 12 h was significantly negatively associated with eGFR, 12 h, 7 days and 3 months after the ESWL. The sensitivity of uNGAL 12 h after ESWL was 60.6%; its specificity was 75.0%, with a positive predictive value of 74.0% and negative predictive value of 61.7%.

Conclusions

uNGAL appears to be a useful biomarker for the assessment and prediction of AKI. It was noticed that uNGAL had the highest predictive value 12 h after the ESWL treatment.

Pyruvate Kinase M2: A Novel Biomarker for the Early Detection of Acute Kidney Injury

The identification of biomarkers for the early detection of acute kidney injury (AKI) is clinically important. Acute kidney injury (AKI) in critically ill patients is closely associated with increased morbidity and mortality. Conventional biomarkers, such as serum creatinine (SCr) and blood urea nitrogen (BUN), are frequently used to diagnose AKI. However, these biomarkers increase only after significant structural damage has occurred. Recent efforts have focused on identification and validation of new noninvasive biomarkers for the early detection of AKI, prior to extensive structural damage. Furthermore, AKI biomarkers can provide valuable insight into the molecular mechanisms of this complex and heterogeneous disease. Our previous study suggested that pyruvate kinase M2 (PKM2), which is excreted in the urine, is a sensitive biomarker for nephrotoxicity. To appropriately and optimally utilize PKM2 as a biomarker for AKI requires its complete characterization. This review highlights the major studies that have addressed the diagnostic and prognostic predictive power of biomarkers for AKI and assesses the potential usage of PKM2 as an early biomarker for AKI. We summarize the current state of knowledge regarding the role of biomarkers and the molecular and cellular mechanisms of AKI. This review will elucidate the biological basis of specific biomarkers that will contribute to improving the early detection and diagnosis of AKI.

Novel biomarkers of acute kidney injury: Evaluation and evidence in urologic surgery

Patients undergoing urologic surgery are at risk of acute kidney injury (AKI) and consequently long-term deterioration in renal function. AKI is further associated with significantly higher odds of perioperative complications, prolonged hospital stay, higher mortality and costs. Therefore, better awareness and detection of AKI, as well as identification of AKI determinants in the urological surgery setting is warranted to pre-empt and mitigate further deterioration of renal function in patients at special risk. New consensus criteria provide precise definitions of diagnosis and description of the severity of AKI. However, they rely on serum creatinine (SCr), which is known to be an inaccurate marker of early changes in renal function. Therefore, several new urinary and serum biomarkers promise to address the gap associated with the use of SCr. Novel biomarkers may complement SCr measurement or most likely improve the diagnostic accuracy of AKI when used in combinations. However, novel biomarkers have to prove their clinical applicability, accuracy, and cost effectiveness prior to implementation into clinical practice. Most preferably, novel biomarkers should help to positively improve a patient’s long-term renal functional outcomes. The purpose of this review is to discuss currently available biomarkers and to review their clinical evidence within urologic surgery settings.

Antioxidant signal and kidney injury molecule-1 levels in shockwave lithotripsy induced kidney injury

PURPOSE

Shockwave lithotripsy (SWL) induces acute kidney injury (AKI) that extends from the papilla to the outer cortex by causing ischemia and the production of nephrotoxic agents. Direct ischemic damage and the generation of free radicals cause injury to the proximal tubular cells. Kidney injury molecule-1 (KIM-1) is a transmembrane glycoprotein that is upregulated in proximal tubular cells after ischemic or nephrotoxic injury and is not expressed in healthy kidneys. We evaluated the extent of free radical production in response to SWL by measuring urinary total antioxidant capacity (TAC) and total oxidant status (TOS). Furthermore, we investigated the severity of SWL-induced kidney injury by measuring KIM-1 expression levels.

PATIENTS AND METHODS

The study population comprised 30 patients who were carefully selected and 30 age and sex matched control subjects. All patients received the same SWL procedure. Midstream urine samples were collected from patients before SWL and at 120 minutes after SWL. Urine KIM-1 levels were measured by enzyme-linked immunosorbent assay, and TAC and TOS were measured via spectrophotometry.

RESULTS

Mean levels of TAC (2.88±0.56 mmolTxEq/L),TOS (8.27±1.57 μmolH2O2Eq/L), and KIM-1 (0.55±0.08 ng/mL) before SWL were not significantly different from mean TAC, TOS, and KIM-1 levels measured from the control group at 2.81±0.42 mmolTxEq/L, 10.73±1.4 μmolH2O2Eq/L, and 0.51±0.07 ng/mL, respectively. Two hours after SWL, mean urine TAC levels (2.81±0.85 mmolTxEq/L, P=0.02) were decreased and mean KIM-1 expression (0.85±0.11 ng/mL, P=0.01) was significantly increased, but there was no significant difference in mean TOS levels (11.24±1.9 μmolH2O2Eq/L, P=0.627) compared with the control group.

CONCLUSIONS

The increased burden of free radical oxidants in the setting of decreasing antioxidant capacity may be one of the initial indicators of AKI after SWL. Moreover, KIM-1 demonstrates great potential as an early and noninvasive biomarker of SWL-induced kidney injury.