Monitoring treatment of acute kidney injury with damage biomarkers

The effects of antibiotic therapy on neonatal sepsis-associated acute kidney injury

AIM

Neonatal sepsis remains one of the most dangerous conditions in the neonatal intensive care units. One of the organs affected by sepsis is the kidney, making acute kidney injury (AKI) a common complication of sepsis. Treatment of sepsis almost always involves antibiotic therapy, which by itself may cause some adverse effects, including nephrotoxicity. We analyzed the mutual effect of antibiotic therapy and sepsis on AKI in an experimental and clinical study in infants and neonatal rats.

MATERIALS AND METHODS

We evaluated the influence of therapy with different antibiotics on the appearance of AKI markers (blood urea nitrogen (BUN), neutrophil gelatinase-associated lipocalin (NGAL), clusterin, interleukin-18 (IL-18), kidney injury molecule-1 (KIM-1), monocyte chemoattractant protein 1 (MCP-1), calbindin, glutation-S-transferase subtype π (GST-π)) and liver injury markers in newborns with or without clinical signs of sepsis in the intensive care unit. In parallel, we analyzed the development of AKI in experimental lipopolysaccharide (LPS)-induced systemic inflammation in newborn rats accompanied by antibiotic therapy.

KEY FINDINGS

We showed that therapy with metronidazole or ampicillin in combination with sulbactam had a beneficial effect in children with suspected sepsis, resulting in a decrease in AKI markers levels. However, treatment of newborns with netilmicin, cefepime, linezolid, or imipenem in combination with cilastatin worsened kidney function in these patients.

SIGNIFICANCE

This prospective study indicates which antibiotics are preferable in neonatal sepsis and which should be used with caution in view of the risk of AKI development.

The renal damage and mechanisms relevant to antitumoral drugs

Over the past few decades, significant progress has been made in the development of drugs to combat cancer. It is unfortunate that these drugs can also lead to various kidney injuries and imbalances in electrolyte levels. Nephrotoxicity caused by chemotherapy drugs can impact different parts of the kidneys, including the glomeruli, renal tubules, interstitium, or renal microvessels. Despite the existing knowledge, our understanding of the mechanisms underlying the renal damage caused by antitumoral drugs remains incomplete. In this review, we aim to provide a comprehensive overview of the specific types of kidney injury and the mechanisms responsible for the drug-mediated renal damage, and briefly discuss possible prevention and treatment measures. Sensitive blood and urine biomarkers can provide clinicians with more information about kidney injury detection and reference value for subsequent treatment options. In addition, we emphasize that both oncologists and nephrologists have a responsibility to remain vigilant against the potential nephrotoxicity of the drugs. It's crucial for experts in both fields to collaborate in early detection, monitoring and prevention of kidney damage.

Endotoxic kidney injury in Beagle dogs assessed by serum creatinine and symmetric dimethylarginine, and urinary neutrophil gelatinase-associated lipocalin and clusterin

Sepsis of Gram negative bacterial origin results in lipopolysaccharide-induced endotoxemia. This often leads to acute kidney injury (AKI) and its recognition remains a challenge and delays treatment. As renal damage occurs before a rise in serum creatinine is detected, new early biomarkers of kidney injury need to be explored. The aim of this study was to determine changes in serum parameters of renal function and urine biomarkers of renal injury. This was a descriptive study. Endotoxemia was induced intravenously in six anaesthetized Beagles (T1). To achieve normotension, dogs received fluids (T2), followed by a continuous infusion of noradrenaline and dexmedetomidine or 0.9% NaCl (T3). Ten minutes later, the dogs received fluids (T4) and noradrenaline and dexmedetomidine or 0.9% NaCl in a crossover manner (T5). At each timepoint, blood and urine were collected for serum creatinine, urea, symmetric dimethylarginine, urine protein/creatinine (UPC) ratio, urine neutrophil-gelatinase-associated lipocalin (U-NGAL), U-NGAL/creatinine ratio, urine clusterin (U-clusterin) and U-clusterin/creatinine ratio. Data were analyzed using a mixed-effect model taking into account time and stage of veterinary AKI (VAKI). Three of six dogs had a VAKI stage ≥1; one with anuria and elevated creatinine. Serum creatinine (P < 0.001), U-NGAL/creatinine ratio (P = 0.01) and U-clusterin/creatinine ratio increased over time (P < 0.01). The UPC ratio (mean (range) 0.68 (0.35-2.3) versus 0.39 (0.15-0.71) P < 0.01) and U-NGAL (3164 pg/mL (100-147,555) versus 100 (100-14,524), P = 0.01) were higher in VAKI stage ≥1 versus stage 0, respectively. Endotoxemia induced VAKI stage ≥1 in half of the dogs. Repeated measurement of selected parameters could detect AKI early.

Renal-Protective Roles of Lipoic Acid in Kidney Disease

The kidney is a crucial organ that eliminates metabolic waste and reabsorbs nutritious elements. It also participates in the regulation of blood pressure, maintenance of electrolyte balance and blood pH homeostasis, as well as erythropoiesis and vitamin D maturation. Due to such a heavy workload, the kidney is an energy-demanding organ and is constantly exposed to endogenous and exogenous insults, leading to the development of either acute kidney injury (AKI) or chronic kidney disease (CKD). Nevertheless, there are no therapeutic managements to treat AKI or CKD effectively. Therefore, novel therapeutic approaches for fighting kidney injury are urgently needed. This review article discusses the role of α-lipoic acid (ALA) in preventing and treating kidney diseases. We focus on various animal models of kidney injury by which the underlying renoprotective mechanisms of ALA have been unraveled. The animal models covered include diabetic nephropathy, sepsis-induced kidney injury, renal ischemic injury, unilateral ureteral obstruction, and kidney injuries induced by folic acid and metals such as cisplatin, cadmium, and iron. We highlight the common mechanisms of ALA's renal protective actions that include decreasing oxidative damage, increasing antioxidant capacities, counteracting inflammation, mitigating renal fibrosis, and attenuating nephron cell death. It is by these mechanisms that ALA achieves its biological function of alleviating kidney injury and improving kidney function. Nevertheless, we also point out that more comprehensive, preclinical, and clinical studies will be needed to make ALA a better therapeutic agent for targeting kidney disorders.

Kidney Injury Biomarkers in Leptospirosis

Leptospirosis is a zoonotic infection with a global distribution, though it has a greater impact on marginalized rural agricultural and urban communities in developing countries. Kidney injury, which can lead to severe and lethal infections, is the most frequent complication associated with leptospirosis. Novel biomarkers are being studied as tools for assessing kidney injury in different pathological processes to improve early detection. This review aimed to gather information on the use of novel kidney biomarkers for human leptospirosis. A search of the literature was carried out in September 2021 using the parameters "((kidney) OR (renal) OR (chronic kidney disease) OR (acute kidney injury)) AND ((biomarker) OR (marker)) AND ((Leptospira) OR (leptospirosis))". The review identified 11 original studies that evaluated the performance of 15 kidney biomarkers related to leptospirosis. Assessment of the evidence for biomarker utility was limited because of the small number of studies and sample sizes. Although some biomarkers were associated with kidney disease, no specific biomarker appeared to be ready for clinical practice, and more research in this field is necessary.

Catalase activity as signal of antioxydant system affection under influence of limb ischemia-reperfusion

The use of hemostatic tourniquet is a proved means of primary care. However, systemic disorders, as well as ultrastructural, in the area of compression can significantly worsen the condition of the injured organism. The aim. Estimation of catalase level in rats’ liver on the background of modifications of ischemic-reperfusion syndrome to know the severest pathogenic combination for organism. Materials and methods. 260 white adult male rats were divided into 5 groups: control (KG), EG1 – simulation of isolated ischemia-reperfusion syndrome (IRS) of the limb, EG2 – simulation of isolated volumetric blood loss, EG3 – combination of IRS of the limb with blood loss, EG4 – simulation of isolated mechanical injury of the thigh, EG5 – combination of IRS of the limb and mechanical injury. The variability of catalase level in liver was analyzed. Results. It was found that each of the experimental interventions has led to changes of catalase activity in the liver. The most expressed pathological expressions were observed on the 3rd after interventions, when the studied index in EG3 was lower than in EG1 and EG2 in 6,2 times and by 33,1 %. On the 7th day catalase activity in EG3 was in 9,4 times and by 44,5 % times lower than in EG1 and in EG2 data concordantly. The combination of limb ischemia-reperfusion with blood loss in EG3 led to exhausting of liver antioxydant enzyme catalase in the most critical posttraumatic period (day 3). The same, but less significant effect was registered in the group of combination of mechanical trauma with ischemia-reperfusion in EG5. This proved the role of the tourniquet as a factor that complicated the course of traumatic disease due to ischemic reperfusion. Conclusions. In this experiment, founded risk factors of combination of ischemia-reperfusion with heavy blood loss emphasized the importance and particular attention on such widespread method of bleeding tratment, as the imposition of a tourniquet, as in our experiment it triggered risk factors of ischemia-reperfusion. It was shown katalase activity depression respectively to the periods of increasing of lipid peroxydation. There was peculiarity, that on the base of isolated IRS catalase activity was increased in 2,5 times comparely to control group, whereas the hardest depression of it was found on the background of IRS, combined with blood loss – catalase activity was lower, comparely to KG – in 2,5 times. The importance of understanding the suppression of hepatocytes’ antyoxydants is great, as it might help in prevention the development of liver failure or hepatorenal syndrome on the background of limb ischemia-reperfusion.

A Review of Specific Biomarkers of Chronic Renal Injury and Their Potential Application in Nonclinical Safety Assessment Studies

A host of novel renal biomarkers have been developed over the past few decades which have enhanced monitoring of renal disease and drug-induced kidney injury in both preclinical studies and in humans. Since chronic kidney disease (CKD) and acute kidney injury (AKI) share similar underlying mechanisms and the tubulointerstitial compartment has a functional role in the progression of CKD, urinary biomarkers of AKI may provide predictive information in chronic renal disease. Numerous studies have explored whether the recent AKI biomarkers could improve upon the standard clinical biomarkers, estimated glomerular filtration rate (eGFR), and urinary albumin to creatinine ratio, for predicting outcomes in CKD patients. This review is an introduction to alternative assays that can be utilized in chronic (>3 months duration) nonclinical safety studies to provide information on renal dysfunction and to demonstrate specific situations where these assays could be utilized in nonclinical drug development. Novel biomarkers such as symmetrical dimethyl arginine, dickkopf homolog 3, and cystatin C predict chronic renal injury in animals, act as surrogates for GFR, and may predict changes in GFR in patients over time, ultimately providing a bridge from preclinical to clinical renal monitoring.

Advances in Detection of Kidney Transplant Injury

Early detection of graft injury after kidney transplantation is key to maintaining long-term good graft function. Graft injury could be due to a multitude of factors including ischaemia reperfusion injury, cell or antibody-mediated rejection, progressive interstitial fibrosis and tubular atrophy, infections and toxicity from the immunosuppressive drugs themselves. The current gold standard for assessing renal graft dysfunction is renal biopsy. However, biopsy is usually late when triggered by a change in serum creatinine and of limited utility in diagnosis of early injury when histological changes are equivocal. Therefore, there is a need for timely, objective and non-invasive diagnostic techniques with good early predictive value to determine graft injury and provide precision in titrating immunosuppression. We review potential novel plasma and urine biomarkers that offer sensitive new strategies for early detection and provide major insights into mechanisms of graft injury. This is a rapidly expanding field, but it is likely that a combination of biomarkers will be required to provide adequate sensitivity and specificity for detecting graft injury.

Therapeutic Effects of the Combination of Alpha-Lipoic Acid (ALA) and Coenzyme Q10 (CoQ10) on Cisplatin-Induced Nephrotoxicity

Background

Nephrotoxicity of cisplatin has been recognized since its introduction more than 25 years ago. However, despite intense efforts to develop less toxic and equally effective alternatives, cisplatin continues to be widely prescribed. Aim and Objectives. The study is aimed at assessing the possible prophylactic effect of coenzyme Q10 (CoQ10) and alpha-lipoic acid (ALA) (separately or in combination) on experimentally cisplatin-induced nephrotoxicity. Subjects and Methods. An experimental study was performed on adult male albino rats (n = 40), weighing 200–250 g. Rats were randomly divided into 5 groups: group I (normal saline control), group II (cisplatin control), group III (CoQ10 and cisplatin), group IV (ALA and cisplatin), and group V (CoQ10, ALA, and cisplatin). CoQ10 and/or ALA were given as pretreatment for 9 days, followed by cisplatin injection in the 10th day of the study, followed by a short posttreatment course for 3 days. Renal functions, tissue antioxidant activity, and inflammatory markers (tumor necrosis factor, TNF) were estimated along with histopathological study.

Results

Renal function tests and urinary proteins were significantly higher within group II compared with other groups (P value <0.001). Creatinine clearance was significantly higher with combination therapy (group V compared to other groups). Both TNF and malondialdehyde (MDA) were significantly higher within group II whereas GSH content, catalase, and superoxide dismutase (SOD) were significantly lower in group II. MDA level was significantly lower when combination therapy was used. Marked renal damage was histologically detected in the cisplatin group, whereas the least renal damage was noticed in the combination group.

Conclusion

The study confirmed the role of antioxidants in preventing nephrotoxicity caused by cisplatin; the prophylactic effect of combined therapy with CoQ10 and ALA is superior to that of monotherapy.

Translational Safety Biomarkers of Kidney Injury

Acute kidney injury continues to be a common problem and there continues to be a medical need for sensitive translational biomarkers for clinical monitoring. The past decade has yielded unprecedented progress in fundamental research into novel kidney biomarker evaluation and the mechanistic understanding of kidney injury; as such, these novel biomarkers increasingly are being used in preclinical drug development and in early clinical trials of drug candidates on a case-by-case basis, as well as in medical and veterinary practice. With the recent successful clinical qualification of a subset of novel accessible biomarker candidates for use in early phase clinical trials, continued clinical evaluation may enable expanded regulatory qualification for more generalized clinical use. This review provides a comprehensive overview about the discovery and development of kidney safety biomarkers with a focus on current progress in nonclinical research, progress toward translation to the clinic, and perspectives on future opportunities.

Diagnostic roles of urinary kidney injury molecule 1 and soluble C5b-9 in acute tubulointerstitial nephritis

Acute tubulointerstitial nephritis (ATIN) is a common cause of acute kidney injury characterized by inflammatory cells infiltrating in the interstitium. The present study aimed to explore noninvasive biomarkers that might indicate activity of pathological injuries and help direct treatment. Fifty-four patients with clinical-pathologically diagnosed ATIN from January 1, 2014, to June 30, 2016, at Peking University First Hospital were enrolled. Urine samples were collected on the morning of renal biopsy and assessed for urinary kidney injury molecule-1 (KIM-1) and urinary soluble C5b-9 (sC5b-9). Immunofluorescence staining for KIM-1 and C5b-9 was performed in biopsied kidney sections from ATIN cases. The clinical and pathological relevance of the two urinary biomarkers was analyzed. Both urinary KIM-1 and sC5b-9 values were significantly elevated in patients with ATIN compared with healthy controls. The urinary KIM-1 level positively correlated with urinary N-acetyl-β-d-glucosaminidase (r = 0. 542, P = 0.001) and the pathological tubular injury score (r = 0.469, P < 0.001), whereas the urinary sC5b-9 level was related to pathological activity scores for tubular injury (r = 0.413, P = 0.002), interstitial inflammation (r = 0.388, P = 0.004), and treatment response (r = 0.564, P < 0.001). Urinary KIM-1 tended to have better diagnostic value for tubular injury than urinary sC5b-9, whereas only urinary sC5b-9 was able to demonstrate severe interstitial inflammation. A combination of urinary KIM-1 and sC5b-9 had an area under the receiver-operating characteristic curve of 0.864 (95% confidence interval: 0.766-0.963, P < 0.001, sensitivity: 75%, specificity: 88%) for acute tissue injury in ATIN. KIM-1 expression was markedly increased in renal tubular cells in both ATIN and acute tubular necrosis conditions, whereas a significant upregulation of C5b-9 was only detected in the tubular cells and interstitial cells in ATIN cases. Urinary KIM-1 is a specific biomarker for renal tubular injury in ATIN, whereas urinary sC5b-9 is valuable in demonstrating severe interstitial inflammation. The combination of these two biomarkers helps identify patients at an acute injury stage and, therefore, might facilitate clinical evaluation and guide immunosuppressive therapy.

Early identification of acute kidney injury in Russell's viper (Daboia russelii) envenoming using renal biomarkers

BACKGROUND

Acute kidney injury (AKI) is a major complication of snake envenoming, but early diagnosis remains problematic. We aimed to investigate the time course of novel renal biomarkers in AKI following Russell's viper (Daboia russelii) bites.

METHODOLOGY/PRINCIPAL FINDINGS

We recruited a cohort of patients with definite Russell's viper envenoming and collected serial blood and urine samples on admission (<4h post-bite), 4-8h, 8-16h, 16-24h, 1 month and 3 months post-bite. AKI stage (1-3) was defined using the Acute Kidney Injury Network criteria. AKI stages (1-3) were defined by the Acute Kidney Injury Network (AKIN) criteria. There were 65 Russell's viper envenomings and 49 developed AKI: 24 AKIN stage 1, 13 stage 2 and 12 stage 3. There was a significant correlation between venom concentrations and AKI stage (p = 0.007), and between AKI stage and six peak biomarker concentrations. Although most biomarker concentrations were elevated within 8h, no biomarker performed well in diagnosing AKI <4h post-bite. Three biomarkers were superior to serum creatinine (sCr) in predicting AKI (stage 2/3) 4-8h post-bite: serum cystatin C (sCysC) with an area under the receiver operating curve (AUC-ROC), 0.78 (95%CI:0.64-0.93), urine neutrophil gelatinase-associated lipocalin (uNGAL), 0.74 (95%CI:0.59-0.87) and urine clusterin (uClu), 0.81 (95%CI:0.69-0.93). No biomarker was better than sCr after 8h. Six other urine biomarkers urine albumin, urine beta2-microglobulin, urine kidney injury molecule-1, urine cystatin C, urine trefoil factor-3 and urine osteopontin either had minimal elevation, and/or minimal prediction for AKI stage 2/3 (AUC-ROC<0.7).

CONCLUSIONS/SIGNIFICANCE

AKI was common and sometimes severe following Russell's viper bites. Three biomarkers uClu, uNGAL and sCysC, appeared to become abnormal in AKI earlier than sCr, and may be useful in early identification of envenoming.

Predictive risk factors of acute kidney injury after cytoreductive surgery and cisplatin-based hyperthermic intra-peritoneal chemotherapy for ovarian peritoneal carcinomatosis

OBJECTIVE

The aim of our study was to assess the incidence and identify the predictive risk factors of acute kidney injury after cytoreductive surgery and cisplatin-based hyperthermic intra-peritoneal chemotherapy.

METHODS

This is a retrospective study from two centers evaluating patients with advanced or recurrent ovarian cancer who underwent cytoreductive surgery followed by cisplatin-based hyperthermic intra-peritoneal chemotherapy from January 2007 to December 2013. Patients were classified into two groups according to the occurrence of acute kidney injury, defined as a glomerular filtration rate at post-operative day 7 25% lower than at day 0. We also evaluated acute kidney injury following Risk, Injury, Failure, Lost and End-stage kidney function criteria. Univariate and multivariate analyses were conducted in order to assess the association between different variables and the occurrence of acute kidney injury.

RESULTS

Sixty-six patients were included: 29 (44%) underwent first-line treatment and 37 (56%) were treated for recurrent disease. The incidence of post-operative acute kidney injury was 48%. After multivariate analysis, hypertension (OR 18.6; 95% CI 1.9 to 182.3; p=0.012) and low intra-operative diuresis (OR 0.5; 95% CI 0.4 to 0.8; p=0.001) were associated with acute kidney injury.

CONCLUSION

The incidence of acute kidney injury after cytoreductive surgery and cisplatin-based hyperthermic intra-peritoneal chemotherapy was high. Hypertension and low intra-operative diuresis were independent risk factors for this complication. Adequate peri-operative hydration, in order to maintain correct diuresis, could decrease the occurrence of acute kidney injury in patients undergoing cytoreductive surgery plus hyperthermic intra-peritoneal chemotherapy.

Urinary protein biomarkers of kidney injury in patients receiving cisplatin chemotherapy

Despite recent progress in the development of novel approaches to treat cancer, traditional antineoplastic drugs, such as cisplatin, remain a mainstay of regimens targeting solid tumors. Use of cisplatin is limited by acute kidney injury, which occurs in approximately 30% of patients. Current clinical measures, such as serum creatinine and estimated glomerular filtration rate, are inadequate in their ability to detect acute kidney injury, particularly when there is only a moderate degree of injury. Thus, there is an urgent need for improved diagnostic biomarkers to predict nephrotoxicity. There is also interest by the U.S. Food and Drug Administration to validate and implement new biomarkers to identify clinical and subclinical acute kidney injury in patients during the drug approval process. This minireview provides an overview of the current literature regarding the utility of urinary proteins (albumin, beta-2-microglobulin, N-acetyl-D-glucosaminidase, kidney injury molecule-1, neutrophil gelatinase-associated lipocalin, and cystatin C) as biomarkers for cisplatin-induced AKI. Many of the well-studied urinary proteins (KIM-1, NGAL, B2M, albumin) as well as emerging biomarkers (calbindin, monocyte chemotactic protein-1, and trefoil factor 3) display distinct patterns of time-dependent excretion after cisplatin administration. Implementation of these biomarker proteins in the oncology clinic has been hampered by a lack of validation studies. To address these issues, large head-to-head studies are needed to fully characterize time-dependent responses and establish accurate cutoff values and ranges, particularly in cancer patients. Impact statement There is growing interest in using urinary protein biomarkers to detect acute kidney injury in oncology patients prescribed the nephrotoxic anticancer drug cisplatin. We aim to synthesize and organize the existing literature on biomarkers examined clinically in patients receiving cisplatin-containing chemotherapy regimens. This minireview highlights several proteins (kidney injury molecule-1, beta-2-microglobulin, neutrophil gelatinase-associated lipocalin, calbindin, monocyte chemotactic protein-1, trefoil factor 3) with the greatest promise for detecting cisplatin-induced acute kidney injury in humans. A comprehensive review of the existing literature may aid in the design of larger studies needed to implement the clinical use of these urinary proteins as biomarkers of kidney injury.

Biomarkers of drug-induced kidney injury

PURPOSE OF REVIEW

Drug-induced kidney injury (DIKI) is an important and potentially modifiable cause of acute kidney injury (AKI). The reliance on traditional markers of kidney injury to diagnose DIKI impedes early detection. Biomarkers of DIKI that facilitate early diagnosis and the identification of high-risk patients are essential to ameliorate the clinical burden of this complication.

RECENT FINDINGS

Recent progress in this area supports the potential utility of several biomarkers for the diagnosis of DIKI, for the prediction of outcomes and also for monitoring responses to potential nephrotoxic or beneficial therapies. Data regarding the impact of clinically relevant factors, such as chronic kidney disease, on biomarker levels represents a further recent advancement. Emerging novel biomarkers include microRNAs, which are showing promise as markers of drug-induced tubular damage. They may also have a role in elucidating the molecular mechanisms of AKI.

SUMMARY

There is compelling evidence to support the use of biomarkers for the early detection of DIKI. Ongoing research is required to delineate their role in prognostication and for the prediction of outcomes. The inclusion of biomarkers in more clinical studies of DIKI would be a welcome advance, which may accelerate their integration into clinical diagnostics.

Environmental exposure to low-doses of ionizing radiation. Effects on early nephrotoxicity in mice

Nuclear accidents of tremendous magnitude, such as those of Chernobyl (1986) and Fukushima (2011), mean that individuals living in the contaminated areas are potentially exposed to ionizing radiation (IR). However, the dose-response relationship for effects of low doses of radiation is not still established. The present study was aimed at investigating in mice the early effects of low-dose internal radiation exposure on the kidney. Adult male (C57BL/6J) mice were divided into three groups. Two groups received a single subcutaneous (s.c.) doses of cesium (¹³⁷Cs) with activities of 4000 and 8000Bq/kg bw. A third group (control group) received a single s.c. injection of 0.9% saline. To evaluate acute and subacute effects, mice (one-half of each group) were euthanized at 72h and 10 days post-exposure to ¹³⁷Cs, respectively. Urine samples were collected for biochemical analysis, including the measurement of F2-isoprostane (F2-IsoP) and kidney injury molecule-1 (KIM-1) levels. Moreover, the concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a sensitive marker of oxidative DNA damage, were measured in renal tissue. Urinary excretion of total protein significantly increased at 72h in mice exposed to Cs4000. Uric acid and lactate dehydrogenase (LDH) decreased significantly at both times post-exposure in animals exposed to Cs8000. After 72h and 10d of exposure to Cs4000, a significant increase in the γ-glutamil transferase (GGT) and N-acetyl-β-D-glucosaminidase (NAG) activities was observed. In turn, F2-IsoP levels increased -mainly in the Cs4000 group- at 72h post-exposure. Following irradiation (¹³⁷Cs), the highest level of KIM-1 was corresponded to the Cs4000 group at 72h. Likewise, the main DNA damage was detected in mice exposed to Cs4000, mainly at 10d after irradiation. The alterations observed in several biomarkers suggest an immediate renal damage following exposure to low doses of IR (given as ¹³⁷Cs). Further investigations are required to clarify the mechanisms involved in the internal IR-induced nephrotoxicity.