Urinary l-type fatty acid-binding protein is a predictor of early renal function after partial nephrectomy

Toll-Like Receptor 4 Induction During Renal Ischemia Correlates with Serum Creatinine in a Pig Model

Objectives: To determine whether toll-like receptor 4 (TLR4), a mediator of organ ischemia-reperfusion injury, is overexpressed during warm ischemia in a porcine solitary kidney model, and whether its expression correlates with creatinine, a surrogate for kidney function. Materials and Methods: Eight adult Yorkshire pigs underwent initial laparoscopic nephrectomy. After 1 week, animals were randomized into two groups: group 1 underwent laparoscopic renal hilar dissection, renal ischemia by cross-clamping, and reperfusion (ischemia group); group 2 underwent laparoscopic renal hilar dissection alone (sham group). Animals were survived to day 7 postrandomization. Peripheral blood was sampled for serum creatinine (sCr) and TLR4 expression at the following time points or corresponding intervals: prenephrectomy, 1-week postnephrectomy (preischemia), after 90 minutes of ischemia, 30 minutes postreperfusion, and at sacrifice. Intragroup TLR4 expression changes were analyzed using repeated measures ANOVA. Intergroup TLR4 expression was compared using Mann-Whitney's test. Correlation between sCr and TLR4 was assessed using Spearman's test. Results: Seven animals completed the experiment (four ischemia and three sham). Relative TLR4 expression significantly increased from baseline levels during ischemia, reperfusion, and sacrifice time points only in the ischemia group, and was significantly higher for the ischemia group after 90 minutes of ischemia (p = 0.034). sCr was significantly higher for the ischemia group during the reperfusion phase (p = 0.048). Relative TLR4 expression level significantly correlated with sCr in the overall cohort (Spearman's rho = 0.69) and in the ischemia group (Spearman's rho = 0.82; p < 0.0001 for each). Conclusions: Warm ischemia in a porcine solitary kidney induces acute overexpression of TLR4 in peripheral blood leukocytes, which is detectable. Relative TLR4 expression level strongly correlated with sCr but had an observable change sooner than change in sCr. Pending further investigation, TLR4 overexpression during renal ischemia may represent a sensitive quantitative marker of unilateral renal injury sustained during nephron-sparing surgery.

Urinary L-type fatty acid-binding protein is a predictor of cisplatin-induced acute kidney injury

Background

Although cisplatin-based chemotherapy is a standard treatment for urothelial carcinoma, it often causes acute kidney injury (AKI). AKI and dysfunction are observed in 25–35% of cisplatin-based chemotherapy patients, who may require treatment down-titration or withdrawal. In this study, we evaluated whether urinary L-FABP is a marker for early diagnosis of cisplatin-caused AKI.

Methods

We included 42 adult patients who underwent cisplatin-based chemotherapy for bladder cancer or upper tract urothelial carcinoma from January 2018 to March 2019. Urinary L-FABP and serum creatinine were measured at 2 and 6 h, and 1, 2, 3, 7 and 28 days after taking cisplatin.

Results

In the first week after receiving cisplatin, 10 patients (23.8%) were diagnosed with AKI (AKI⁺ group). Pre-treatment (baseline) measurements did not significantly differ between the AKI⁺ and AKI⁻ groups. However, urinary L-FABP concentrations rapidly increased in the AKI⁺ group and were significantly greater than in the AKI⁻ group at Hour 2, Hour 6, Day 1 and Day 2. Serum creatinine also significantly differed between the AKI⁺ group and the AKI⁻ group on Days 3 and 7. ROC analysis was performed to evaluate the superiority of urinary L-FABP magnification which had the highest at the hour 6. The urinary L-FABP magnification and levels of aria under curve was 0.977. Based on ROC analysis, the best cut-off value of urinary L-FABP magnification was 10.28 times urinary L-FABP levels at the hour 0 (base line urinary L-FABP).

Conclusions

Acute renal function deterioration was predicted by increased urinary L-FABP excretion within 6 h after receiving CIS-CT and, in those with AKI, the increase in urinary L-FABP excretion preceded the rise in sCr by over 2 days. In contrast, no appreciable changes in urinary L-FABP levels were observed in patients with stable renal function throughout the whole observation period. So early increase in urinary L-FABP may identify patients at risk of cisplatin-induced AKI, who might benefit from treatment to prevent nephrotoxicity.

Trial registration

This study was retrospectively registered.

Role of the Furosemide Stress Test in Renal Injury Prognosis

Risk stratification and accurate patient prognosis are pending issues in the management of patients with kidney disease. The furosemide stress test (FST) has been proposed as a low-cost, fast, safe, and easy-to-perform test to assess tubular integrity, especially when compared to novel plasma and urinary biomarkers. However, the findings regarding its clinical use published so far provide insufficient evidence to recommend the generalized application of the test in daily clinical routine. Dosage, timing, and clinical outcomes of the FST proposed thus far have been significantly different, which further accentuates the need for standardization in the application of the test in order to facilitate the comparison of results between series. This review will summarize published research regarding the usefulness of the FST in different settings, providing the reader some insights about the possible implications of FST in clinical decision-making in patients with kidney disease and the challenges that research will have to address in the near future before widely applying the FST.