Valproic acid treatment attenuates cisplatin-induced kidney injury by suppressing proximal tubular cell damage.

Cisplatin treatment is effective against several types of carcinomas. However, it frequently leads to kidney injury, which warrants effective prevention methods. Sodium valproic acid is a prophylactic drug candidate with a high potential for clinical application against cisplatin-induced kidney injury. Therefore, in this study, we aimed to elucidate the mechanism underlying the prophylactic effect of valproic acid on cisplatin-induced kidney injury in a mouse model and HK2 and PODO cells with cisplatin-induced toxicity. In the mouse model of cisplatin-induced kidney injury, various renal function parameters and tubular damage scores were worsened by cisplatin, but they were significantly improved upon combination with valproic acid. No difference was observed in cisplatin accumulation between the cisplatin-treated and valproic acid-treated groups in whole blood and the kidneys. The mRNA expression levels of proximal tubular damage markers, apoptosis markers, and inflammatory cytokines significantly increased in the cisplatin group 72 h after cisplatin administration but significantly decreased upon combination with valproic acid. In HK2 cells, a human proximal tubular cell line, the cisplatin-induced decrease in cell viability was significantly suppressed by co-treatment with valproic acid. Valproic acid may inhibit cisplatin-induced kidney injury by suppressing apoptosis, inflammatory responses, and glomerular damage throughout the kidneys by suppressing proximal tubular cell damage. However, prospective controlled trials need to evaluate these findings before their practical application.

Discovery of preventive drugs for cisplatin-induced acute kidney injury using big data analysis.

Cisplatin is effective against many types of carcinoma. However, a high rate of renal damage is a clinical problem. Thus, there is a need to establish a method to prevent it. Although various compounds have been reported to be effective against cisplatin-induced renal injury, there are no examples of their clinical application. Therefore, we attempted to search for prophylactic agents with a high potential for clinical application. We used Cascade Eye to identify genes that are altered during cisplatin-induced renal injury, Library of Integrated Network-based Cellular Signatures (LINCS) to identify drugs that inhibit changes in gene expression, and a large database of spontaneous adverse drug reaction reports to identify drugs that could prevent cisplatin-induced kidney injury in clinical practice. In total, 10 candidate drugs were identified. Using the US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS), we identified drugs that reduce cisplatin-induced kidney injury. Fenofibrate was selected as a candidate drug to prevent cisplatin-induced kidney injury based on the FAERS analysis. A model was used to evaluate the efficacy of fenofibrate against cisplatin-induced renal injury. Studies using HK2 cells and mouse models showed that fenofibrate significantly inhibited cisplatin-induced renal injury but did not inhibit the antitumor effect of cisplatin. Fenofibrate is a candidate prophylactic drug with high clinical applicability for cisplatin-induced renal injury. Analysis of data from multiple big databases will improve the search for novel prophylactic drugs with high clinical applicability. For the practical application of these findings, evaluation in prospective controlled trials is necessary.

Vascular Endothelial Dysfunction in the Thoracic Aorta of Rats with Ischemic Acute Kidney Injury: Contribution of Indoxyl Sulfate.

Chronic kidney disease (CKD) and cardiovascular disease are known to be linked, and the involvement of indoxyl sulfate (IS), a type of uremic toxin, has been suggested as one of the causes. It is known that IS induces vascular dysfunction through overproduction of reactive oxygen species (ROS). On the other hand, the involvement of IS in the vascular dysfunction associated with acute kidney injury (AKI) is not fully understood. Therefore, we investigated this issue using the thoracic aorta of rats with ischemic AKI. Ischemic AKI was induced by occlusion of the left renal artery and vein for 45 min, followed by reperfusion 2 weeks after contralateral nephrectomy. One day after reperfusion, there was marked deterioration in renal function evidenced by an increase in plasma creatinine. Furthermore, blood IS levels increased markedly due to worsening renal function. Seven days and 28 days after reperfusion, blood IS levels decreased with the improvement in renal function. Of note, acetylcholine-induced vasorelaxation deteriorated over time after reperfusion, contradicting the recovery of renal function. In addition, 28 days after reperfusion, we observed a significant increase in ROS production in the vascular tissue. Next, we administered AST-120, a spherical adsorbent charcoal, after reperfusion to assess whether the vascular endothelial dysfunction associated with the ischemic AKI was due to a temporary increase in blood IS levels. AST-120 reduced the temporary increase in blood IS levels after reperfusion without influencing renal function, but did not restore the impaired vascular reactivity. Thus, in ischemic AKI, we confirmed that the vascular endothelial function of the thoracic aorta is impaired even after the recovery of kidney injury, probably with excessive ROS production. IS, which increases from ischemia to early after reperfusion, may not be a major contributor to the vascular dysfunction associated with ischemic AKI.

Risk of Hematologic Events With Coadministration of Methotrexate and the Breast Cancer Resistance Protein Inhibitor Febuxostat.

BACKGROUND: The breast cancer resistance protein (BCRP) is a key drug transporter found in the liver, kidney, central nervous system, and gastrointestinal tract. Due to the wide expression of BCRP, interactions of other drugs with methotrexate (MTX) may differ in oral and intravenous MTX users, and understanding of these interactions may be useful in preventing severe adverse events. Febuxostat, a urate-lowering drug, inhibits BCRP. OBJECTIVE: The objective of this study was to clarify the differences in the drug-drug interaction profiles of oral and intravenous methotrexate, associated with BCRP. METHODS: We analyzed the Japanese Adverse Drug Event Report database and compared the frequency of hematologic events in patients taking oral and intravenous MTX, with or without the concomitant use of febuxostat or allopurinol. Hematologic events were defined as pancytopenia and neutropenia. Multiple logistic regression analysis was then used to identify the risk factors for hematologic events in oral and intravenous MTX users. RESULTS: We identified 8 453 oral and 810 intravenous MTX users with 546 and 126 cases of hematologic events, respectively. Compared with those not using febuxostat, a disproportionate number of hematologic events was observed in intravenous MTX users concomitantly using febuxostat (P < 0.01). The multivariate logistic analysis of intravenous MTX users showed that hematologic events were significantly associated with febuxostat use (P < 0.01) and age ≥ 60 years (P < 0.01). CONCLUSION AND RELEVANCE: Our findings suggest that patients being treated with intravenous MTX who concomitantly use febuxostat may be at an increased risk of hematologic events, presumably due to BCRP-mediated drug-drug interaction.

Effects of 5-HT3 receptor antagonists on cisplatin-induced kidney injury.

Nausea, vomiting, and renal injury are the common adverse effects associated with cisplatin. Cisplatin is excreted via the multidrug and toxin release (MATE) transporter, and the involvement of the MATE transporter in cisplatin-induced kidney injury has been reported. The MATE transporter is also involved in the excretion of ondansetron, but the effects of 5-HT3 receptor antagonists used clinically for cisplatin-induced renal injury have not been elucidated. Therefore, the aim of this study was to investigate the effects of 5-HT3 receptor antagonists in a mouse model of cisplatin-induced kidney injury and to validate the results using medical big data analysis of more than 1.4 million reports and a survey of 3000 hospital medical records. The concomitant use of a first-generation 5-HT3 receptor antagonist (ondansetron, granisetron, or ramosetron) significantly increased cisplatin accumulation in the kidneys and worsened renal damage. Conversely, the concomitant use of palonosetron had no effect on renal function compared with the use of cisplatin alone. Furthermore, an analysis of data from the US Food and Drug Administration Adverse Event Reporting System and retrospective medical records revealed that the combination treatment of cisplatin and a first-generation 5-HT3 receptor antagonist significantly increased the number of reported renal adverse events compared with the combination treatment of cisplatin and a second-generation 5-HT3 receptor antagonist. These results suggest that compared with the first-generation antagonists, second-generation 5-HT3 receptor antagonists do not worsen cisplatin-induced acute kidney injury. The findings should be validated in a prospective controlled trial before implementation in clinical practice.