Ezetimibe ameliorates cisplatin-induced nephrotoxicity: A novel therapeutic approach via modulating AMPK/Nrf2/TXNIP signaling.

Cisplatin (Cis) is among the most powerful antineoplastic medications, nevertheless, its serious side effects; particularly nephrotoxicity designates a major concern. Previous studies reported that ezetimibe (Eze), a well-known antihyperlipidemic drug, exerts additional trivial pharmacological effects. In this work, we displayed Eze as an intriguing protective candidate in a cisplatin-induced nephrotoxicity rat model through AMPK activation. Eze (10 mg/kg, p.o.) was administered for two weeks and Cis (10 mg/kg, i.p.) was administered on the 10th day to induce nephrotoxicity in male Wistar rats. Treatment with Eze greatly augmented the phosphorylation of adenosine 5'-monophosphate-activated protein kinase (AMPK) and the antioxidant regulator; nuclear factor erythroid 2-related factor 2 (Nrf2), thus, mitigating oxidative injury through induction of the antioxidant enzymes, such as heme oxygenase-1 (HO-1) and glutathione reductase (GR). As well, Eze relieved inflammation by reducing protein expression of thioredoxin-interacting protein (TXNIP) and nucleotide-binding domain-like receptor protein 3 (NLRP3), which led to a decrease in the release of caspase-1, in addition to, the inflammatory markers IL-18 and IL-1 ß. Besides, Eze ameliorated apoptosis in the renal cells through inhibiting the phosphorylated Apoptosis signal-regulating kinase-1(p-ASK1), caspase-3 and reducing Bax/Bcl2ratio. Correspondingly, histopathological examination corroborated the previous biochemical findings. Collectively, Eze exerts significant renal protection against Cis-induced nephrotoxicity via antioxidant, anti-inflammatory and anti-apoptotic pathways that are probably mediated, at least partly, via activating AMPK/Nrf2/HO-1 pathway and conquering both TXNIP/NLRP3 inflammasome and TXNIP/ASK1 signaling pathways. To confirm the protective effect of Eze via AMPK-activation, an AMPK-inhibitor, dorsomorphin (Dors), when co-administered with Eze abolished its protective effect.

Megalin-related mechanism of hemolysis-induced acute kidney injury and the therapeutic strategy.

Hemolysis-induced acute kidney injury (AKI) is attributed to heme-mediated proximal tubule epithelial cell (PTEC) injury and tubular cast formation due to intratubular protein condensation. Megalin is a multiligand endocytic receptor for proteins, peptides, and drugs in PTECs and mediates the uptake of free hemoglobin and the heme-scavenging protein α1-microglobulin. However, understanding of how megalin is involved in the development of hemolysis-induced AKI remains elusive. Here, we investigated the megalin-related pathogenesis of hemolysis-induced AKI and a therapeutic strategy using cilastatin, a megalin blocker. A phenylhydrazine-induced hemolysis model developed in kidney-specific mosaic megalin knockout (MegKO) mice confirmed megalin-dependent PTEC injury revealed by the co-expression of kidney injury molecule-1 (KIM-1). In the hemolysis model in kidney-specific conditional MegKO mice, the uptake of hemoglobin and α1-microglobulin as well as KIM-1 expression in PTECs was suppressed, but tubular cast formation was augmented, likely due to the nonselective inhibition of protein reabsorption in PTECs. Quartz crystal microbalance analysis revealed that cilastatin suppressed the binding of megalin with hemoglobin and α1-microglobulin. Cilastatin also inhibited the specific uptake of fluorescent hemoglobin by megalin-expressing rat yolk sac tumor-derived L2 cells. In a mouse model of hemolysis-induced AKI, repeated cilastatin administration suppressed PTEC injury by inhibiting the uptake of hemoglobin and α1-microglobulin and also prevented cast formation. Hemopexin, another heme-scavenging protein, was also found to be a novel ligand of megalin, and its binding to megalin and uptake by PTECs in the hemolysis model were suppressed by cilastatin. Mass spectrometry-based semiquantitative analysis of urinary proteins in cilastatin-treated C57BL/6J mice indicated that cilastatin suppressed the reabsorption of a limited number of megalin ligands in PTECs, including α1-microglobulin and hemopexin. Collectively, cilastatin-mediated selective megalin blockade is an effective therapeutic strategy to prevent both heme-mediated PTEC injury and cast formation in hemolysis-induced AKI. © 2024 The Pathological Society of Great Britain and Ireland.

Rodent models of AKI and AKI-CKD transition: an update in 2024.

Despite known drawbacks, rodent models are essential tools in the research of renal development, physiology, and pathogenesis. In the past decade, rodent models have been developed and used to mimic different etiologies of acute kidney injury (AKI), AKI to chronic kidney disease (CKD) transition or progression, and AKI with comorbidities. These models have been applied for both mechanistic research and preclinical drug development. However, current rodent models have their limitations, especially since they often do not fully recapitulate the pathophysiology of AKI in human patients, and thus need further refinement. Here, we discuss the present status of these rodent models, including the pathophysiologic compatibility, clinical translational significance, key factors affecting model consistency, and their main limitations. Future efforts should focus on establishing robust models that simulate the major clinical and molecular phenotypes of human AKI and its progression.

Mechanisms of gelofusine protection in an in vitro model of polymyxin B-associated renal injury.

Polymyxins are a last-resort treatment option for multidrug-resistant gram-negative bacterial infections, but they are associated with nephrotoxicity. Gelofusine was previously shown to reduce polymyxin-associated kidney injury in an animal model. However, the mechanism(s) of renal protection has not been fully elucidated. Here, we report the use of a cell culture model to provide insights into the mechanisms of renal protection. Murine epithelial proximal tubular cells were exposed to polymyxin B. Cell viability, lactate dehydrogenase (LDH) release, polymyxin B uptake, mitochondrial superoxide production, nuclear morphology, and apoptosis activation were evaluated with or without concomitant gelofusine. A megalin knockout cell line was used as an uptake inhibition control. Methionine was included in selected experiments as an antioxidant control. A polymyxin B concentration-dependent reduction in cell viability was observed. Increased viability was observed in megalin knockout cells following comparable polymyxin B exposures. Compared with polymyxin B exposure alone, concomitant gelofusine significantly increased cell viability as well as reduced LDH release, polymyxin B uptake, mitochondrial superoxide, and apoptosis. Gelofusine and methionine were more effective at reducing renal cell injury in combination than either agent alone. In conclusion, the mechanisms of renal protection by gelofusine involve decreasing cellular drug uptake, reducing subsequent oxidative stress and apoptosis activation. These findings would be valuable for translational research into clinical strategies to attenuate drug-associated acute kidney injury.NEW & NOTEWORTHY Gelofusine is a gelatinous saline solution with the potential to attenuate polymyxin-associated nephrotoxicity. We demonstrated that the mechanisms of gelofusine renal protection involve reducing polymyxin B uptake by proximal tubule cells, limiting subsequent oxidative stress and apoptosis activation. In addition, gelofusine was more effective at reducing cellular injury than a known antioxidant control, methionine, and a megalin knockout cell line, indicating that gelofusine likely has additional pharmacological properties besides only megalin inhibition.

IL-22 is secreted by proximal tubule cells and regulates DNA damage response and cell death in acute kidney injury.

Acute kidney injury (AKI) affects over 13 million people worldwide annually and is associated with a 4-fold increase in mortality. Our lab and others have shown that DNA damage response (DDR) governs the outcome of AKI in a bimodal manner. Activation of DDR sensor kinases protects against AKI, while hyperactivation of DDR effector proteins, such as p53, induces cell death and worsens AKI. The factors that trigger DDR to switch from pro-repair to pro-cell death remain to be resolved. Here we investigated the role of interleukin 22 (IL-22), an IL-10 family member whose receptor (IL-22RA1) is expressed on proximal tubule cells (PTCs), in DDR activation and AKI. Using cisplatin and aristolochic acid (AA) induced nephropathy as models of DNA damage, we identified PTCs as a novel source of urinary IL-22. Functionally, IL-22 binding IL-22RA1 on PTCs amplified the DDR. Treating primary PTCs with IL-22 alone induced rapid activation of the DDR. The combination of IL-22 and either cisplatin- or AA-induced cell death in primary PTCs, while the same dose of cisplatin or AA alone did not. Global deletion of IL-22 protected against cisplatin- or AA-induced AKI, reduced expression of DDR components, and inhibited PTC cell death. To confirm PTC IL-22 signaling contributed to AKI, we knocked out IL-22RA1 specifically in kidney tubule cells. IL-22RA1ΔTub mice displayed reduced DDR activation, cell death, and kidney injury compared to controls. Thus, targeting IL-22 represents a novel therapeutic approach to prevent the negative consequences of the DDR activation while not interfering with repair of damaged DNA.

Long-term impact of immediate versus deferred antiretroviral therapy on kidney health in people with HIV.

People with human immunodeficiency virus (HIV) are at risk for chronic kidney disease (CKD) due to HIV and antiretroviral therapy (ART) nephrotoxicity. Immediate ART initiation reduces mortality and is now the standard of care, but the long-term impact of prolonged ART exposure on CKD is unknown. To evaluate this, the Strategic Timing of Antiretroviral Treatment (START) trial randomized 4,684 ART-naïve adults with CD4 cell count under 500 cells/mm3 to immediate versus deferred ART. We previously reported a small but statistically significantly greater decline in estimated glomerular filtration rate (eGFR) over a median of 2.1 years in participants randomized to deferred versus immediate ART. Here, we compare the incidence of CKD events and changes in eGFR and urine albumin/creatinine ratio (UACR) in participants randomized to immediate versus deferred ART during extended follow-up. Over a median of 9.3 years, eight participants experienced kidney failure or kidney-related death, three in the immediate and five in the deferred ART arms, respectively. Over a median of five years of more comprehensive follow-up, the annual rate of eGFR decline was 1.19 mL/min/1.73m2/year, with no significant difference between treatment arms (difference deferred - immediate arm 0.055; 95% confidence interval -0.106, 0.217 mL/min/1.73m2). Results were similar in models adjusted for baseline covariates associated with CKD, including UACR and APOL1 genotype. Similarly, there was no significant difference between treatment arms in incidence of confirmed UACR 30 mg/g or more (odds ratio 1.13; 95% confidence interval 0.85, 1.51). Thus, our findings provide the most definitive evidence to date in support of the long-term safety of early ART with respect to kidney health.

Effect modification of dosing strategy (AUC or trough) on AKI associated with vancomycin in combination with piperacillin/tazobactam or cefepime and meropenem.

Piperacillin-tazobactam (TZP), cefepime (FEP), or meropenem (MEM) and vancomycin (VAN) are commonly used in combination for sepsis. Studies have shown an increased risk of acute kidney injury (AKI) with TZP and VAN compared to FEP or MEM. VAN guidelines recommend area under the curve (AUC) monitoring over trough (Tr) to minimize the risk of AKI. We investigated the association of AKI and MAKE-30 with the two VAN monitoring strategies when used in combination with TZP or FEP/MEM. Adult patients between 2015 and 2019 with VAN > 72 hours were included. Patients with AKI prior to or within 48 hours of VAN or baseline CrCl of ≤30 mL/min were excluded. Four cohorts were defined: FEP/MEM/Tr, FEP/MEM/AUC, TZP/Tr, and TZP/AUC. A Cox Proportional Hazard Model was used to model AKI as a function of the incidence rate of at-risk days, testing monitoring strategy as a treatment effect modification. Multivariable logistic regression was used to model MAKE-30. Overall incidence of AKI was 18.6%; FEP/MEM/Tr = 115 (14.6%), FEP/MEM/AUC = 52 (14.9%), TZP/Tr = 189 (26%), and TZP/AUC = 96 (17.1%) (P < 0.001). Both drug group [(TZP; P = 0.0085)] and monitoring strategy [(Tr; P = 0.0007)] were highly associated with the development of AKI; however, the effect was not modified with interaction term [(TZP*Tr); 0.085)]. The odds of developing MAKE-30 were not different between any group and FEP/MEM/AUC. The effect of VAN/TZP on the development of AKI was not modified by the VAN monitoring strategy (AUC vs trough). MAKE-30 outcomes were not different among the four cohorts.

Population pharmacokinetics and target attainment analysis of vancomycin after intermittent dosing in adults with cystic fibrosis.

Vancomycin is the first-line agent to treat pulmonary infections caused by methicillin-resistant Staphylococcus aureus (MRSA) in people with cystic fibrosis (PwCF). However, there is no consensus on vancomycin initial dosing in this population among health institutions, and there is a large variability in initial dosing across the United States. In this study, we characterized the pharmacokinetics (PK) of vancomycin in PwCF using a population PK approach. The clinical PK data to develop the population PK model were obtained from vancomycin therapeutic monitoring data from PwCF undergoing treatment for infections due to MRSA. The population PK model was then used to perform comprehensive Monte Carlo simulations to evaluate the probability of target attainment (PTA) of 12 different initial dosing scenarios. The area under the curve to minimum inhibitory concentration (MIC) ratio ≥400 mg*h/L and <650 mg*h/L were used as efficacy and toxicity targets for PTA analysis. A total of 181 vancomycin plasma concentrations were included in the analysis. A one-compartment model with first-order elimination best described the data. Weight significantly influenced the vancomycin PK (P < 0.05). In the final model, clearance was estimated as 5.52 L/h/70 kg, and the volume of distribution was 31.5 L/70 kg. The PTA analysis showed that at MIC = 1 µg/mL, doses 1,500 q8h and 2,000 q12h showed the highest %PTA in achieving both efficacy and toxicity targets. The PTA results from this study may potentially inform the initial dosing regimens of vancomycin to treat pulmonary infections due to MRSA in PwCF.

Liraglutide and resveratrol alleviated cyclosporin A induced nephrotoxicity in rats through improving antioxidant status, apoptosis and pro-inflammatory markers.

The recent study delves into the role of both liraglutide and/or resveratrol on the nephropathic affection in rats treated with cyclosporine A (CsA). Rats were intoxicated with CsA (25 mg/kg) orally for 21 days and were supplemented with liraglutide (30 µg/kg) s/c daily and 20 mg/kg of resveratrol (20 mg/kg) orally. At the end of the experiment, serum samples and renal tissues were collected to determine renal damage markers, apoptotic markers, proinflammatory markers, and antioxidant status markers. Kidney function tests and antioxidant activity notably improved in the treated rats (CsA + Lir/CsA + Res/CsA + Lir + Res). Moreover, both Lir and/or Res enhanced Bcl-2 levels while down-regulating the Bax levels in rats treated with CsA. Interestingly, the immune-staining for tumor necrosis factor (TNF-α) was tested negative and mild positive in renal tissue of rats given Lir and/or Res while being treated with Cs A which indicated their anti-inflammatory effect that reduced the renal damage. The findings of this investigation revealed the ameliorative anti-inflammatory in addition to the antioxidant role of both liraglutide and resveratrol against the kidney damage caused due to CsA administration.

Diurnal variation of cisplatin-induced renal toxicity in ICR mice.

Cisplatin (CDDP) is a platinum-based anticancer drug widely prescribed for its effectiveness in treating various forms of cancer. However, its major side effect is nephrotoxicity. Although several methods have been developed to mitigate CDDP-induced nephrotoxicity, an optimal approach has yet to be established. This study aimed to investigate the "chronotoxicity" of CDDP as a potential strategy to reduce its side effects. Male ICR mice were treated with CDDP (20 mg/kg, intraperitoneal injection, one shot) at zeitgeber time (ZT) 2 or ZT14 (light or dark phase). After 72 h, we collected plasma and kidney and evaluated several markers. We found that body weight change between ZT2 and ZT14 by CDDP was comparable. In contrast, many toxicological factors, such as plasma blood urine nitrogen, plasma creatinine, renal oxidative stress (malondialdehyde), DNA damage (γH2AX), acute kidney injury biomarker (KIM-1), and inflammation (Tnfα), were significantly induced at ZT14 compared to than that of ZT2. Our present data suggested that chronotoxicology might provide beneficial information on the importance of administration timings for toxic evaluations and unacceptable side effects.

Chromatin accessibility and transcriptional landscape in PK-15 cells during early exposure to Aflatoxin B1.

Aflatoxin B1 (AFB1) not only causes significant losses in livestock production but also poses a serious threat to human health. It is the most carcinogenic among known chemicals. Pigs are more susceptible to AFB1 and experience a higher incidence. However, the molecular mechanism of the toxic effect of AFB1 remains unclear. In this study, we used assay for transposase-accessible chromatin using sequencing (ATAC-seq) and RNA-seq to uncover chromatin accessibility and gene expression dynamics in PK-15 cells during early exposure to AFB1. We observed that the toxic effects of AFB1 involve signaling pathways such as p53, PI3K-AKT, Hippo, MAPK, TLRs, apoptosis, autophagy, and cancer pathways. Basic leucine zipper (bZIP) transcription factors (TFs), including AP-1, Fos, JunB, and Fra2, play a crucial role in regulating the biological processes involved in AFB1 challenge. Several new TFs, such as BORIS, HNF1b, Atf1, and KNRNPH2, represent potential targets for the toxic mechanism of AFB1. In addition, it is crucial to focus on the concentration of intracellular zinc ions. These findings will contribute to a better understanding of the mechanisms underlying AFB1-induced nephrotoxicity and offer new molecular targets.

Mitigation of cisplatin-induced acute kidney injury through oral administration of FAAH Inhibitor PF-04457845.

Fatty acid amide hydrolase (FAAH) serves as the primary enzyme responsible for degrading the endocannabinoid anandamide (AEA). Inhibition of FAAH, either through pharmacological means or genetic manipulation, can effectively reduce inflammation in various organs, including the brain, colon, heart, and kidneys. Infusion of a FAAH inhibitor into the kidney medulla has been shown to induce diuretic and natriuretic effects. FAAH knockout mice have shown protection against both post-ischemia reperfusion injury and cisplatin-induced acute kidney injury (AKI), although through distinct mechanisms. The present study was based on the hypothesis that pharmacological inhibition of FAAH activity could mitigate cisplatin-induced AKI, exploring potential renoprotective mechanism. Male wild type C57BL/6 were administered an oral gavage of a FAAH inhibitor (PF-04457845, 5mg/kg) or vehicle (10% PEG200+5% Tween80+normal saline) at 72, 48, 24, and 2 hours before and 24 and 48 hours after a single intraperitoneal injection of cisplatin (Cis, 25 mg/kg). Mice were euthanatized 72 hours after cisplatin treatment. Compared to vehicle-treated mice, PF-04457845-treated mice showed a decrease of cisplatin-induced plasma creatinine, blood urea nitrogen levels, kidney injury biomarkers (NGAL and KIM-1) and renal tubular damage. The renal protection from oral gavage of PF-04457845 against cisplatin-induced nephrotoxicity was associated with an enhanced AEA tone and reduced levels of DNA damage response biomarkers p53 and p21. Our work demonstrates that PF-04457845 effectively alleviates cisplatin-induced nephrotoxicity in mice, underscoring the potential of orally targeting FAAH as a novel strategy to prevent cisplatin nephrotoxicity. Significance Statement Oral administration of FAAH inhibitor, can reduce cisplatin-induced DNA damage response, tubular damages, and kidney dysfunction. Inactivation of FAAH could be a potential strategy to prevent cisplatin-induced nephrotoxicity.

Combined effect of naringin and adipose tissue-derived mesenchymal stem cell on cisplatin nephrotoxicity through Sirtuin1/Nrf-2/HO-1 signaling pathway: a promising nephroprotective candidate.

Cisplatin nephrotoxicity is a well-known emergency clinical condition caused by oxidative stress and inflammation. Naringin (NAR) is considered an antioxidant agent with renoprotective effects capable of removing reactive oxygen species. Adipose tissue-derived mesenchymal stem cells (AD-MSCs) are reported to have anti-inflammatory and antioxidant properties. The present research examined the renoprotective effect of the combination of NAR and AD-MSCs as opposed to each one alone on cisplatin-induced nephrotoxicity through SIRT-1/Nrf-2/HO-1 pathway. This study included five groups (n = 8 each) of male Sprague-Dawley rats (200 - 220 g): sham, cisplatin: rats receiving cisplatin (6.5 mg/kg, i.p.) on the 4th day; NAR+cisplatin: rats pretreated with NAR (1 week, i.p.) + cisplatin on the 4th day; AD-MSCs: rats receiving AD-MSCs (1 × 106) by injection through the tail vein on the 5th day + cisplatin on the 4th day; and NAR+AD-MSCs+cisplatin. On the 8th day, the animals were anesthetized to obtain tissue and blood samples. Biochemical factors, inflammation, oxidative stress, and gene expression were explored. Cisplatin increased blood urea nitrogen, creatinine, inflammation, and oxidative stress. Moreover, mRNA expression of Sirtuin1, nuclear factor erythroid 2-related factor 2 (Nrf-2), and heme oxygenase-1 (HO-1) remarkably reduced. Furthermore, cisplatin led to a disturbance in kidney structure (glomerular atrophy, cell infiltrations, and tubular dysfunction) as confirmed by histology findings. However, NAR pretreatment, AD-MSC administration, or a combination of both significantly reversed these changes. Overall, when used together, NAR and AD-MSCs had stronger cisplatin-induced effects on kidney dysfunction by inhibiting inflammation, reducing oxidative stress, and increasing the Sirtuin1/Nrf-2/HO-1 pathway.

Integrative analysis of metabolomics and proteomics reveals mechanism of berberrubine-induced nephrotoxicity.

Berberrubine (BRB), a main metabolite of berberine, has stronger hypoglycemic and lipid-lowering activity than its parent form. We previously found that BRB could cause obvious nephrotoxicity, but the molecular mechanism involved remains unknown. In this study, we systematically integrated metabolomics and quantitative proteomics to reveal the potential mechanism of nephrotoxicity caused by BRB. Metabolomic analysis revealed that 103 significant- differentially metabolites were changed. Among the mentioned compounds, significantly upregulated metabolites were observed for phosphorylcholine, sn-glycerol-3-phosphoethanolamine, and phosphatidylcholine. The top three enriched KEGG pathways were the mTOR signaling pathway, central carbon metabolism in cancer, and choline metabolism in cancer. ERK1/2 plays key roles in all three metabolic pathways. To further confirm the main signaling pathways involved, a proteomic analysis was conducted to screen for key proteins (such as Mapk1, Mapk14, and Caspase), indicating the potential involvement of cellular growth and apoptosis. Moreover, combined metabolomics and proteomics analyses revealed the participation of ERK1/2 in multiple metabolic pathways. These findings indicated that ERK1/2 regulated the significant- differentially abundant metabolites determined via metabolomics analysis. Notably, through a cellular thermal shift assay (CETSA) and molecular docking, ERK1/2 were revealed to be the direct binding target involved in BRB-induced nephrotoxicity. To summarize, this study sheds light on the understanding of severe nephrotoxicity caused by BRB and provides scientific basis for its safe use and rational development.

Pre-clinical evaluation of biomarkers for the early detection of nephrotoxicity following alpha-particle radioligand therapy.

PURPOSE: Cancer treatment with alpha-emitter-based radioligand therapies (α-RLTs) demonstrates promising tumor responses. Radiolabeled peptides are filtered through glomeruli, followed by potential reabsorption of a fraction by proximal tubules, which may cause acute kidney injury (AKI) and chronic kidney disease (CKD). Because tubular cells are considered the primary site of radiopeptides' renal reabsorption and potential injury, the current use of kidney biomarkers of glomerular functional loss limits the evaluation of possible nephrotoxicity and its early detection. This study aimed to investigate whether urinary secretion of tubular injury biomarkers could be used as an additional non-invasive sensitive diagnostic tool to identify unrecognizable tubular damage and risk of long-term α-RLT nephrotoxicity. METHODS: A bifunctional cyclic peptide, melanocortin 1 ligand (MC1L), labeled with [203Pb]Pb-MC1L, was used for [212Pb]Pb-MC1L biodistribution and absorbed dose measurements in CD-1 Elite mice. Mice were treated with [212Pb]Pb-MC1L in a dose-escalation study up to levels of radioactivity intended to induce kidney injury. The approach enabled prospective kidney functional and injury biomarker evaluation and late kidney histological analysis to validate these biomarkers. RESULTS: Biodistribution analysis identified [212Pb]Pb-MC1L reabsorption in kidneys with a dose deposition of 2.8, 8.9, and 20 Gy for 0.9, 3.0, and 6.7 MBq injected [212Pb]Pb-MC1L doses, respectively. As expected, mice receiving 6.7 MBq had significant weight loss and CKD evidence based on serum creatinine, cystatin C, and kidney histological alterations 28 weeks after treatment. A dose-dependent urinary neutrophil gelatinase-associated lipocalin (NGAL, tubular injury biomarker) urinary excretion the day after [212Pb]Pb-MC1L treatment highly correlated with the severity of late tubulointerstitial injury and histological findings. CONCLUSION: Urine NGAL secretion could be a potential early diagnostic tool to identify unrecognized tubular damage and predict long-term α-RLT-related nephrotoxicity.

Extended peptide receptor radionuclide therapy: evaluating nephrotoxicity and therapeutic effectiveness in neuroendocrine tumor patients receiving more than four treatment cycles.

PURPOSE: Currently, the most used peptide receptor radionuclide therapy (PRRT) regimen for neuroendocrine tumors comprises 4 treatment cycles, and there is not enough large-scale data to support the safety of more individualized extended PRRT. This study aims to evaluate the therapeutic effectiveness and potential nephrotoxicity related to PRRT using more than four treatment cycles. METHODS: In this retrospective analysis, we included patients who had received at least four PRRT cycles and had available follow-up data. We analyzed renal function indicators before and after multiple treatments, comparing nephrotoxicity in patients receiving four cycles ("standard") with those receiving more than four ("extended treatment"). Nephrotoxicity was assessed via creatinine levels and CTCAE creatinine grades. Treatment effectiveness was gauged using Kaplan-Meier survival analysis, focusing on overall survival and disease-specific survival (DSS). Statistical analyses were performed using SPSS version 26 (IBM), R 4.2.3, and GraphPad Prism 9.0.0. Statistical significance was defined as a P-value of less than 0.05. RESULTS: Our study cohort consisted of 281 patients in the standard group and 356 in the extended treatment group. No significant differences in baseline characteristics or renal function were noted between the two groups pre-treatment. Mean post-treatment creatinine levels did not significantly differ between the standard (89.30 ± 51.19 µmol/L) and extended treatment groups (93.20 ± 55.98 µmol/L; P = 0.364). Similarly, there was no statistical significance between the CTCAE creatinine grades of the two groups (P = 0.448). Adverse renal events were observed in 0.4% of patients in the standard group and 1.1% in the extended treatment group. After a median follow-up time of 88.3 months, we found that median overall survival was significantly higher in the extended treatment group (72.8 months) compared to the standard treatment group (52.8 months). A Cox regression analysis further supported these findings, indicating a better prognosis for the extended treatment group in terms of overall survival (HR: 0.580, P < 0.001) and DSS (HR: 0.599, P < 0.001). CONCLUSION: Our findings suggest that extending PRRT treatment beyond the standard four cycles may be a safe and effective therapeutic strategy for NET patients. This approach could be particularly beneficial for patients experiencing disease recurrence or progression following standard treatment.

Betaine ameliorates arsenic-induced kidney injury in mice by mitigating oxidative stress-mediated inflammation.

Arsenic, an environmental pollutant and poisonous metalloid, has adverse effects on different body organs, including the kidneys. Betaine is a natural nutrient that has many beneficial health effects. This research was conducted to examine the impact of betaine on nephrotoxicity caused by inorganic arsenic (NaAsO2) in mice. Mice were separated into following groups: control, NaAsO2 (50 ppm), NaAsO2 (50 ppm) + betaine (500 mg/kg), and betaine (500 mg/kg). Mice were received NaAsO2 via drinking water for 8 consecutive weeks and betaine was given to the animals via gavage once daily in the 7th and 8th weeks of the study. Upon completion of the study, the mice were euthanized and samples of serum and kidney were obtained for further evaluations. Administration of NaAsO2 increased the levels of blood urea nitrogen and creatinine in the serum. It enhanced the amounts of renal malondialdehyde and decreased the total thiol levels, as well as the activity of antioxidant enzymes (catalase, superoxide dismutase, and glutathione peroxidase). Furthermore, it enhanced the levels of renal inflammatory indicators (tumor necrosis factor-alpha and nitric oxide). Western blot results exhibited an increase in the protein expression of nuclear factor kappa B (NF-κB), and phosphorylated NF-κB in NaAsO2-treated mice. Histopathological results also confirmed kidney damage caused by NaAsO2. However, treatment with betaine improved NaAsO2-related kidney injuries in mice. The results of this work indicated that betaine can attenuate kidney damage caused by NaAsO2 by inhibiting oxidative stress and inflammation.

Nrf2/FSP1/CoQ10 axis-mediated ferroptosis is involved in sodium aescinate-induced nephrotoxicity.

Sodium aescinate (SA), an active compound found in horse chestnut seeds, is widely used in clinical practice. Recently, the incidence of SA-induced adverse events, particularly renal impairment, has increased. Our previous work demonstrated that SA causes severe nephrotoxicity via nephrocyte ferroptosis; however, the underlying mechanism remains to be fully elucidated. In the current study, we investigated additional molecular pathways involved in SA-induced nephrotoxicity. Our results showed that SA inhibited cell viability, disrupted cellular membrane integrity, and enhanced reactive oxygen species (ROS), ferrous iron (Fe2+), and malondialdehyde (MDA) levels, as well as lipid peroxidation in rat proximal renal tubular epithelial cell line (NRK-52E) cells. SA also depleted coenzyme Q10 (CoQ10, ubiquinone) and nicotinamide adenine dinucleotide (NADH) and reduced ferroptosis suppressor protein 1 (FSP1) and polyprenyltransferase (coenzyme Q2, COQ2) activity, triggering lipid peroxidation and ROS accumulation in mouse kidneys and NRK-52E cells. The overexpression of COQ2, FSP1, or CoQ10 (ubiquinone) supplementation effectively attenuated SA-induced ferroptosis, whereas iFSP1 or 4-formylbenzoic acid (4-CBA) pretreatment exacerbated SA-induced nephrotoxicity. Additionally, SA decreased nuclear factor-erythroid-2-related factor 2 (Nrf2) levels and inhibited Nrf2 binding to the -1170/-1180 bp ARE site in FSP1 promoter, resulting in FSP1 suppression. Overexpression of Nrf2 or its agonist dimethyl fumarate (DMF) promoted FSP1 expression, thereby improving cellular antioxidant capacity and alleviating SA-induced ferroptosis. These results suggest that SA-triggers renal injury through oxidative stress and ferroptosis, driven by the suppression of the Nrf2/FSP1/CoQ10 axis.

Development of a predictive model for nephrotoxicity during tacrolimus treatment using machine learning methods.

AIM: When administering tacrolimus, therapeutic drug monitoring is recommended because nephrotoxicity, an adverse event, occurs at supra-therapeutic whole-blood concentrations of tacrolimus. However, some patients exhibit nephrotoxicity even at the recommended concentrations, therefore establishing a therapeutic range of tacrolimus concentration for the individual patient is necessary to avoid nephrotoxicity. This study aimed to develop a model for individualized prediction of nephrotoxicity in patients administered tacrolimus. METHODS: We collected data, such as laboratory test data at tacrolimus initiation, concomitant drugs and tacrolimus whole-blood concentration, from medical records of patients who received oral tacrolimus. Nephrotoxicity was defined as an increase in serum creatinine levels within 60 days of tacrolimus initiation. We built 13 prediction models based on different machine learning algorithms: logistic regression, support vector machine, gradient-boosting trees, random forest and neural networks. The best performing model was compared with the conventional model, which classifies patients according to the tacrolimus concentration alone. RESULTS: Data from 163 and 41 patients were used to construct models and evaluate the best performing one, respectively. Most of the patients were diagnosed with inflammatory or autoimmune diseases. The best performing model was built using a support vector machine; it showed a high F2 score of 0.750 and outperformed the conventional model (0.500). CONCLUSIONS: A machine learning model to predict nephrotoxicity in patients during tacrolimus treatment was developed using tacrolimus whole-blood concentration and other patient data. This model could potentially assist in identifying high-risk patients who require individualized target therapeutic concentrations of tacrolimus prior to treatment initiation to prevent nephrotoxicity.

Kidney donor age of 50 years or above is a risk factor for calcineurin inhibitor-induced nephrotoxicity.

INTRODUCTION: Calcineurin inhibitor (CNI)-induced nephrotoxicity (CNI-T) is a post-transplantation complication that leads to graft dysfunction. Older-donor kidney grafts may be susceptible to chronic CNI exposure because of long-term arteriolar damage. The primary aim of this study was to examine the CNI-T incidence and time-course changes in the graft function according to donor age. METHODS: We included 334 kidney transplant recipients. CNI-T was defined by Banff arteriolar hyaline thickening scores of ≥2 based on allograft protocol biopsy. Depending on donor age, participants were divided into the D > 70 (≥70 years), D60 (60-69 years), D50 (50-59 years), and D < 49: (≤49 years) groups. We investigated the extent to which CNI-T affected the transplanted kidney function. Patients who did not develop CNI-T during the study period were included in the non-CNI-T group; the remaining were grouped into the CNI-T group. RESULTS: The CNI-T incidence was higher in donors aged >50 years. Compared to D < 49, the CNI-T risk was 1.86 times higher in D50 and 2.9 times higher in D > 70. Furthermore, the CNI-T group exhibited a significantly lower graft function 10 years after transplantation. CONCLUSION: CNI-T incidence increases in donors aged ≥50 years and affects renal function after 10 years.