Urine NGAL and KIM-1-Tubular Injury Biomarkers in Long-Term Survivors of Childhood Solid Tumors: A Cross-Sectional Study

Elevated serum GDF15 level as an early indicator of proximal tubular cell injury in acute kidney injury

Acute kidney injury (AKI) is a high-burden medical condition, and current diagnostic criteria can only assess AKI after full manifestation. Stress marker growth differentiation factor 15 (GDF15) was reported to have a role in kidney injury of critical patients. Herein, we evaluated dynamic changes in GDF15 across diverse AKI scenarios and explored the underlying mechanisms of its induction. Serum parameters and renal lesions were analyzed in mouse models of unilateral ischemia-reperfusion injury (uni-IRI) and unilateral ureteral obstruction (UUO). The human proximal tubular (HK-2) cell line was stimulated with various conditions, and induction of GDF15 expression was determined. Serum GDF15 levels were rapidly induced within hours after injury in both animal models and declined thereafter. Renal GDF15 expression exhibited a temporary and early increased induction and was mainly located in aquaporin 1-positive proximal tubules in both unilateral AKI model tissues. In cell experiments, rapid GDF15 production was highly induced by t-BHP and CoCl2. Treatment with either an antioxidant or mitogen-activated protein kinase inhibitors abolished t-BHP- and CoCl2-mediated GDF15 expression. In addition, silencing nuclear factor erythroid 2-related factor 2 expression also reduced the basal and t-BHP- or CoCl2-mediated GDF15 expression level in HK-2 cells. Our data showed that elevated serum GDF15 levels could be detected early in unilateral AKI models without notable alterations in kidney function parameters. GDF15 expression was associated with oxidative stress- and hypoxia-mediated proximal tubular cell injury. These data document that elevated serum GDF15 can possibly serve as an early biomarker for proximal tubular cell injury in AKI.

Kidney Injury Evoked by Fine Particulate Matter: Risk Factor, Causation, Mechanism and Intervention Study

Fine particulate matter (PM2.5) is suggested to pose a severe risk to the kidneys by inducing functional degradation and chronic kidney diseases (CKD). This study aims to explore the nephrotoxicity of PM2.5 exposure and the underlying mechanism. Herein, based on the UK Biobank, it is found that per interquartile range (IQR) increase in PM2.5 is associated with a 6% (95% CI: 1%-11%), 7% (95% CI: 3%-11%), 9% (95% CI: 4%-13%), 11% (95% CI: 9%-13%), and 10% (95% CI: 8%-12%) increase in the risk of nephritis, hydronephrosis, kidney stone, acute renal failure, and CKD, respectively. In experimental study, noticeable kidney injury, which is the initiation of kidney diseases, is observed with PM2.5 exposure in C57BL/6N mice (n = 8), accompanied with oxidative stress, autophagy and pyroptosis. In vitro, HK-2 cells with PM2.5-stimulation exhibit tubulopathy, increased reactive oxygen species (ROS) generation and activated pyroptosis and autophagy. All changes are abolished by ROS scavenger of N-acetyl-L-cysteine (NAC) both in vivo and in vitro. In conclusion, the study provides evidence showing that PM2.5 exposure is associated with 5 kinds of kidney diseases by directly inducing nephrotoxicity, in which ROS may be the potential target by triggering autophagy and pyroptosis.

Understanding fluid dynamics and renal perfusion in acute kidney injury management

Acute kidney injury (AKI) is associated with an increased risk of morbidity, mortality, and healthcare expenditure, posing a major challenge in clinical practice, and affecting about 50% of patients in the intensive care unit (ICU), particularly the elderly and those with pre-existing chronic comorbidities. In health, intra-renal blood flow is maintained and auto-regulated within a wide range of renal perfusion pressures (60-100 mmHg), mediated predominantly through changes in pre-glomerular vascular tone of the afferent arteriole in response to changes of the intratubular NaCl concentration, i.e. tubuloglomerular feedback. Several neurohormonal processes contribute to regulation of the renal microcirculation, including the sympathetic nervous system, vasodilators such as nitric oxide and prostaglandin E2, and vasoconstrictors such as endothelin, angiotensin II and adenosine. The most common risk factors for AKI include volume depletion, haemodynamic instability, inflammation, nephrotoxic exposure and mitochondrial dysfunction. Fluid management is an essential component of AKI prevention and management. While traditional approaches emphasize fluid resuscitation to ensure renal perfusion, recent evidence urges caution against excessive fluid administration, given AKI patients' susceptibility to volume overload. This review examines the main characteristics of AKI in ICU patients and provides guidance on fluid management, use of biomarkers, and pharmacological strategies.

Phloretamide Protects against Diabetic Kidney Damage and Dysfunction in Diabetic Rats by Attenuating Hyperglycemia and Hyperlipidemia, Suppressing NF-κβ, and Upregulating Nrf2

Potent hypoglycemic and antioxidant effects were recently reported for the apple-derived phenolic compound phloretamide (PLTM). The renoprotective effects of this compound are yet to be shown. This study aimed to examine the potential of PLTM to prevent diabetic nephropathy in streptozotocin-induced diabetic rats and to examine the possible mechanisms of protection. Non-diabetic and STZ-diabetic male rats were treated orally by gavage with either the vehicle or with PTLM (200 mg/kg; twice/week) for 12 weeks. PTLM significantly increased urine volume and prevented glomerular and tubular damage and vacuolization in STZ-diabetic rats. It also increased creatinine excretion and reduced urinary albumin levels and the renal levels of kidney injury molecule-1 (KIM-1), 8-hydroxy-2'-deoxyguanosine (8-OHdG), neutrophil gelatinase-associated lipocalin (NGAL), and nephrin in the diabetic rats. PTLM also prevented an increase in the nuclear levels of NF-κβ, as well as the total levels of tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), caspase-3, and Bax in the kidneys of diabetic rats. These effects were associated with reduced serum levels of triglycerides, cholesterol, and low-density lipoprotein cholesterol. In both the control and diabetic rats, PTLM significantly reduced fasting plasma glucose and enhanced the renal mRNA and cytoplasmic levels of Nrf2, as well as the levels of Bcl2, superoxide dismutase (SOD), and glutathione (GSH). However, PTLM failed to alter the cytoplasmic levels of keap1 in diabetic rats. In conclusion, PTLM prevents renal damage and dysfunction in STZ-diabetic rats through its hypoglycemic and hypolipidemic activities, as well as through its antioxidant potential, which is mediated by activating the Nrf2/antioxidant axis.

Long-term cisplatin nephrotoxicity after childhood cancer: a systematic review and meta-analysis

BACKGROUND

Cisplatin is a chemotherapeutic drug commonly used in the treatment of many childhood solid malignancies. It is known to cause long-term nephrotoxicity, most commonly manifesting as reduced glomerular filtration rate and hypomagnesaemia. Existing literature regarding the epidemiology of long-term nephrotoxicity in childhood cancer describes large variation in prevalence and risk factors.

OBJECTIVES

This study is to evaluate the prevalence of, and risk factors for, long-term cisplatin nephrotoxicity after treatment for childhood cancer.

STUDY ELIGIBILITY CRITERIA

Studies were eligible for inclusion if they: (i) evaluated participants treated with cisplatin who were diagnosed with cancer < 18 years of age; (ii) investigated any author-defined measure of nephrotoxicity; and (iii) performed this evaluation 3 or more months after cisplatin cessation. Studies whose scope was broader than this were included if appropriate subgroup analysis was performed.

RESULTS

Prevalence of reduced glomerular filtration rate (GFR) ranged between 5.9 and 48.1%. Pooled prevalence of reduced GFR using studies with a modern consensus threshold of 90 ml/min/1.73 m2 was 29% (95% CI 0.0-58%). Prevalence of hypomagnesaemia ranged between 8.0 and 71.4%. Pooled prevalence of hypomagnesaemia was 37% (95% CI 22-51%). Substantial heterogeneity was present, with I2 statistics of 94% and 73% for reduced GFR and hypomagnesaemia respectively. All large, long-term follow-up studies described increased risk of reduced GFR with increasing cumulative cisplatin dose. Included studies varied as to whether cisplatin was a risk factor for proteinuria, and whether age was a risk factor for cisplatin nephrotoxicity.

LIMITATIONS

A wide range of study methodologies were noted which impeded analysis. No studies yielded data from developing health-care settings. No non-English studies were included, further limiting generalisability.

CONCLUSIONS

Both of the most common manifestations of long-term cisplatin nephrotoxicity have a prevalence of approximately a third, with increasing cumulative dose conferring increased risk of nephrotoxicity. Further work is needed to characterise the relationship between reduced GFR and hypomagnesaemia, investigate other risk factors and understand the interindividual variation in susceptibility to nephrotoxicity.

Exploring the Utility of Urinary Creatinine Adjustment for KIM-1, NGAL, and Cystatin C for the Assessment of Kidney Function: Insights from the C-KidnEES Cohort

Normalization of urinary biomarkers of kidney injury is a common practice in clinical and research settings to account for variations in urine concentration, and urinary creatinine is often used as a reference. However, to date, there is no consensus on the adjustment of urinary biomarkers with creatinine, and both absolute and creatinine-adjusted biomarker levels are adopted for making interpretations of kidney health. Hence, the present study aimed to investigate the associations of urinary creatinine with three widely used kidney injury biomarkers, KIM-1, NGAL, and cystatin C, to validate the applicability of urinary creatinine as a reference for normalization. A cross-sectional study was performed with 2100 students, 10-18 years of age in the Children's Kidney Environmental Exposure Study (C-KidnEES) cohort established in Sri Lanka. As identified in linear regression analyses, normalization of urinary KIM-1, NGAL, and Cys-C to urinary creatinine did not result in significant under-adjustment or over-adjustment to the absolute urinary concentrations, giving no specific rationale for creatinine adjustment. Hence, absolute urinary concentrations of the above biomarkers can be adopted for the characterization of subclinical kidney injury in adolescents in community studies where early morning urine sampling is practiced. However, for spot urine samples, consideration of both absolute and creatinine-adjusted biomarker levels would be a better approach.

Acute Kidney Injury after Multiple Cycles of Cisplatin Chemotherapy: A Nomogram for Risk Assessment

INTRODUCTION

Acute kidney injury (AKI) caused by cisplatin is common and has a higher incidence of multiple use, resulting in a poor short- and long-term prognosis for patients. There is currently no good premedication AKI risk assessment tool. The aim of this study was to establish an AKI risk assessment nomogram for patients with multiple cisplatin applications.

METHODS

This study was a retrospective analysis of patients who were treated with non-first-time cisplatin chemotherapy regimen at Changzhou Second People's Hospital affiliated to Nanjing Medical University from January 2016 to January 2022. All data from the development group were used to screen the impact factors of AKI via univariate and multivariate analyses. A nomogram was developed based on these impact factors and verified with verification group. The area under the curve (AUC) of receiver operating characteristic (ROC) curve, calibration curves, and decision curve analyses (DCAs) were used to evaluate the nomogram.

RESULTS

Among the 256 patients enrolled in 450 cycles of chemotherapy, 282 were in the development cohort (97 AKI), and 168 were in the validation cohort (61 AKI). Multivariate logistic regression revealed that age, hypertension, diabetes, serum cystatin C (sCysC), urinary kidney injury molecule-1 (uKim1), and a single dose of cisplatin were independently associated with AKI. The results showed that our model yielded satisfied diagnostic performance with an AUC value of 0.887 and 0.906 using the development group and on verification group. The calibration plots and DCA showed the superior clinical applicability of the nomogram. These results were verified in the validation cohort.

CONCLUSION

A nomogram combining functional (sCysC) and tubular (uKim1) injury biomarkers with conventional clinical factors might assess the risk of AKI after multiple cycles of cisplatin chemotherapy.

Evaluation of kidney dysfunction in childhood cancer survivors

BACKGROUND

The major increase in the survival rate among children with cancer is due to improvement in the diagnosis and treatment. Despite this increase, childhood cancer survivors (CCS) are at high risk of developing late complications such as nephrotoxicity due to chemotherapy. So, we aimed to detect early subclinical kidney dysfunction among CCS.

METHODS

This cross-sectional study was implemented on 52 survivors of childhood cancer recruited from Pediatric Oncology Unit, Menoufia University. Laboratory evaluations for each participant, including complete blood count, serum urea, creatinine, urinary protein, urinary calcium, uric acid, and serum cystatin C and urinary Neutrophil Gelatinase Associated Lipocalin (UrNGAL) by ELISA were obtained.

RESULTS

Estimated GFR was decreased in 23.1% of cases, with elevated serum cystatin C, UrNGAL and UrNGAL/Cr. There was a significant increase of Uprotein/Cr, UCa/Cr, UACR (p = 0.02), UrNGAL and UrNGAL/Cr (P < 0.001) in patients with tubular dysfunction compared without tubular dysfunction. There was a significant difference between two groups regarding cisplatin (P = 0.03) and high-dose methotrexate chemotherapy (p = 0.04). The AUCs for detecting kidney tubular dysfunction by UrNGAL and UrNGAL/Cr were 0.807 and 0.747.

CONCLUSION

A significant tubular dysfunction among childhood cancer survivors receiving chemotherapy as cisplatin and high-dose methotrexate.

IMPACT

Detection of kidney dysfunction mainly tubular in childhood cancer survivors after finishing chemotherapy. Urinary NGAL is a good predictor for detection of tubular dysfunction in childhood cancer survivors after finishing chemotherapy.

Urinary Beta-2-Microglobulin and Late Nephrotoxicity in Childhood Cancer Survivors

The objectives of this study were to evaluate urinary beta-2-microglobulin (β2M) levels in long-term childhood cancer survivors and to establish its association with anticancer drug-induced nephrotoxicity. The study consisted of 165 childhood cancer survivors (CCS) who were in continuous complete remission. We reported that CCS had a significantly higher level of β2M (p < 0.001) and β2M/Cr. ratio (p < 0.05) than healthy peers. Among all participants, 24 (14.5%) had decreased eGFR (<90 mL/min/1.73 m²). A significant positive correlation between β2M/Cr. ratio and body mass index (coef. 14.48, p = 0.046) was found. Furthermore, higher levels of urinary β2M were detected among CCS with a longer follow-up time (over 5 years) after treatment. Subjects with decreased eGFR showed statistically higher urinary β2M levels (20.06 ± 21.56 ng/mL vs. 8.55 ± 3.65 ng/mL, p = 0.007) compared with the healthy peers. Twelve survivors (7.2%) presented hyperfiltration and they had higher urinary β2M levels than CCS with normal glomerular filtration (46.33 ± 93.11 vs. 8.55 ± 3.65 ng/mL, p = 0.029). This study did not reveal an association between potential treatment-related risk factors such as chemotherapy, surgery, radiotherapy, and the urinary β2M level. The relationship between treatment with abdominal radiotherapy and reduced eGFR was confirmed (p < 0.05). We demonstrated that urinary beta-2-microglobulin may play a role in the subtle kidney injury in childhood cancer survivors; however, the treatment-related factors affecting the β2M level remain unknown. Further prospective studies with a longer follow-up time are needed to confirm the utility of urinary β2M and its role as a non-invasive biomarker of renal dysfunction.