Cisplatin Nephrotoxicity Research Articles

Retinoic Acid Alleviates Cisplatin-Induced Acute Kidney Injury Through Activation of Autophagy.

Cisplatin-induced acute kidney injury (CIAKI) is a common complication in patients receiving cisplatin-based chemotherapy. But the effective therapies for CIAKI are not available. Retinoic acid (RA), the main derivative of vitamin A, has the potential to reduce inflammation and fibrosis in renal injury. However, the effect and mechanism of RA on CIAKI are still unclear. The aim of this study is to investigate whether RA can alleviate CIAKI through activation of autophagy. In this study, we evaluated the effect of RA, RA’s effect on autophagy and apoptosis after cisplatin-induced injury on renal tubular epithelial cells (RTECs) by LDH assay, immunoblotting and TUNEL staining. Then we established Atg5flox/flox:Cagg-Cre mice in which Cagg-Cre is tamoxifen inducible, and Atg5 is conditional deleted after tamoxifen injection. The effect of RA and RA’s effect on autophagy on CIAKI model were evaluated by biochemical assessment, hematoxylin and eosin (HE) staining, and immunoblotting in the control and autophagy deficient mice. In vitro, RA protected RTECs against cisplatin-induced injury, activated autophagy, and inhibited cisplatin-induced apoptosis. In vivo, RA attenuated cisplatin-induced tubular damage, shown by improved renal function, decreased renal cast formation, decreased NGAL expression, and activated autophagy in the control mice. Furthermore, the nephrotoxicity of cisplatin was aggravated, and the protective effect of RA was attenuated in autophagy deficient mice, indicating that RA works in an autophagy-dependent manner on CIAKI. RA activates autophagy and alleviates CIAKI in vivo and in vitro.Thus RA may be a renoprotective adjuvant for cisplatin-based chemotherapy.

Nano Ellagic Acid Counteracts Cisplatin-Induced Upregulation in OAT1 and OAT3: A Possible Nephroprotection Mechanism.

Cisplatin is an anticancer drug commonly used for solid tumors. However, it causes nephrotoxicity. OAT1 and OAT3 are organic anion transporters known to contribute to the uptake of cisplatin into renal tubular cells. The present study was designed to examine the protective role of ellagic acid nanoformulation (ellagic acid nano) on cisplatin-induced nephrotoxicity in rats, and the role of OAT1/OAT3 in this effect. Four groups of male Wistar rats were used (n = 6): (1) control, (2) cisplatin (7.5 mg/kg single dose, intraperitoneal), (3) cisplatin + ellagic acid nano (1 mg/kg), and (4) cisplatin + ellagic acid nano (2 mg/kg). Nephrotoxic rats treated with ellagic acid nano exhibited a significant reduction in elevated serum creatinine, urea, and oxidative stress marker, malondialdehyde (MDA). Additionally, ellagic acid nano restored renal glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Ellagic acid nano improved the histopathological changes induced by cisplatin, such as tubular dilatation, necrosis, and degeneration. Interestingly, OAT1 and OAT3 showed significantly lower expression at both mRNA and protein levels following ellagic acid nano treatment relative to the cisplatin-exposed group. These findings reveal a potential inhibitory role of ellagic acid antioxidant on OAT1 and OAT3 expression and thus explains its nephroprotective effect against cisplatin nephrotoxicity.

P0534THE EFFECT OF HIGH FAT DIET INTAKE AND FOOD SUPPLY RESTRICTION ON CISPLATIN NEPHROTOXICITY IN MICE

Abstract Background and Aims Nephrotoxicity is a major side effect of cis-diamminedichloroplatinum (II) (cisplatin), which is widely used for cancer therapy. The nephrotoxicity is associated with the excessive formation of reactive oxygen species (ROS) and oxidation of cell components. Here, we investigate whether cisplatin nephrotoxicity can be controlled by the regulation of food supply which is associated with cellular production of ROS. Method Male mice were administered with either cisplatin or saline. Before cisplatin administration, mice were high-fat diet (HFD) feeding for 7 days, no-food supply for 2 days, 2 days no-food supply and refeeding with normal diet (ND), and normal diet. Renal function was analyzed by plasma creatinine (PCr) and blood urea nitrogen (BUN) concentration. Kidney cell damage was evaluated by periodic acid shiff staining and transmission electron microscope analysis. Results Cisplatin injection induced the disruption of kidney tubular cells and also increased BUN and PCr concentration. These increases were greatest in the HFD feeding mice, whereas .these increases were lowest in the food restricted mice. Levels of DNA oxidation and lipid peroxidation increased in the kidney after cisplatin injection and these increase were also greatest in the kidney of HFD feeding mice and lowest food restricted mice. Mitochondrial damage was observed in the proximal tubule cells after cisplatin injection and this mitochondria damage was more severe in the HFD feeding mice than ND feeding mice. Cisplatin increased the expression of fission 1 in the kidney, whereas reduced the expression of opa-1 expression. These cisplatin induced changes were greater in the HFD feeding mice than the ND feeding mice. Conclusion High fat diet feeding worsens cisplatin-induced nephrotoxicity along with increased oxidative stress and mitochondrial damage, whereas food restriction reduces this cisplatin nephrotoxicity. These data indicate that cisplatin nephrotoxicity is controlled by food supply, suggesting that energy metabolism is associated with cisplatin nephrotoxicity.

P0528RENOPROTECTIVE EFFECT OF IL-34 INHIBITION ON CISPLATIN-INDUCED NEPHROTOXICITY IN MICE

Abstract Background and Aims Interleukin (IL)-34, a macrophage (Mø) mediator, is expressed by tubular epithelial cells (TECs). However, the influence of IL-34 on TECs injury has not been fully elucidated. We investigated the physiological properties of IL-34 on TECs damage caused by cisplatin-nephrotoxicity (CP-N). Method 7-week-old male C57BL/6 (B6) mice (n=16) were fasted for 8 hours and then induced CP-N by intraperitoneal injection (IP) of CP (25 mg/kg) on day 0. Groups of animals were given either anti-mouse IL-34 antibody (CP+anti-IL-34 Ab, 400 ng/kg, n=8) or vehicle (CP+V, equal volume of saline, n=8) daily by IP from day -1 to day 2. Three age-matched male B6 mice were used as normal control (NC). All mice were sacrificed on day 3. In addition, mouse renal proximal TECs (MRTEpiC) were cultured to analyze the inhibitory effects of IL-34 on CP-induced TEC apoptosis. Cells were stimulated with CP (2 μg/mL), then treated with or without anti-IL-34 Ab (1000 pg/mL). Results Compared to the NC, CP+V mice exhibited marked acute kidney injury (AKI) and upregulated expression of IL-34 and its two receptors, cFMS and PTP-ζ. Compared to the vehicle treatment, anti-IL-34 Ab treatment significantly suppressed the intrarenal expression levels of IL-34 and its two receptors in CP-N mice; it also significantly suppressed serum IL-34 levels (72.1 ± 5.6 vs. 40.4 ± 7.5 pg/mL, p=0.013). Additionally, treatment with anti-IL-34 Ab significantly improved serum Cr levels (1.3 ± 0.2 vs. 0.7 ± 0.1 mg/mL, p=0.033), ameliorated tubulointerstitial injury (numbers of casts/HPF: 11.9 ± 2.6 vs. 6.5 ± 1.8, p=0.048), and suppressed the number of F4/80+ Mø (17.5 ± 2.7 vs. 11.1 ± 1.1/HPF, p=0.041) and TUNEL+ apoptotic cells (29.2 ± 4.9 vs. 16.7 ± 2.7/HPF, p=0.036) in CP-N mice. The renal cortical transcript levels of Kim-1, MIP-1/CCL3, TNF-α, and Bax were significantly lower in the CP+anti-IL-34 Ab mice than in the CP+V mice. Furthermore, the CP+anti-IL-34 Ab mice showed significantly less renal infiltration of CD11b+F4/80+TNF-α+ cells. In vitro, stimulation with CP induced the expression of IL-34 and its two receptors in MRTEpiC. Treatment with anti-IL-34 Ab significantly suppressed CP-induced caspase-3 and Bax expression with degradation of ERK1/2 phosphorylation in the damaged MRTEpiC. Conclusion IL-34 secreted from damaged TECs was involved in the progression of CP-N. Inhibition of IL-34 with neutralizing antibody directly prevented CP-induced TEC apoptosis by inhibiting the phosphorylation of ERK1/2. Blocking of IL-34 might suppressed proliferation of cytotoxic Mø, which indirectly led to the attenuation of CP-N. Thus, IL-34 represents a potential as therapeutic target for AKI with TECs injury.

P0517RENAL STEM CELLS (ARPCS) AS A NEPHROPROTECTIVE APPROACH DURING CISPLATIN-INDUCED ACUTE KIDNEY INJURY: A DEFENSE MECHANISM BY EXTRACELLULAR VESICLES CARRYING THE CYP1B1 GENE

Abstract Background and Aims Cisplatin, is a nonspecific cytotoxic agent that primarily interferes with cellular DNA replication and the cell cycle, nevertheless it lacks tumor selectivity and acts also in normal cells. The most serious adverse reaction of cisplatin is Acute Kidney Injury (AKI), limiting its use and efficacy in chemotherapy. Cisplatin nephrotoxicity is observed in more than 30% of older patients, however the mechanism of nephrotoxicity remains unclear and specific preventive measures are not available. Today, there is an urgent need for specific nephroprotective strategies to be used during cisplatin chemotherapy. Recently, we found that tubular stem/progenitor cells (tARPC) are able to protect the tubular epithelial (RPTEC) from cisplatin induced injury, preserving their proliferation and inhibiting apoptosis. The aim of this study was to identify the molecular mechanisms involved in tARPC-mediated resistance to cisplatin. Method Co-cultures of RPTEC cells and tARPCs were exposed to cisplatin (2.5 µM) for 6 h and then kept in culture for 96 h. Gene expression profile was obtained from tARPCs and RPTECs by Agilent SurePrint G3 Human Gene Expression Microarrays. Genespring and R software were used for the analysis. Gene expression data were validated by Real-time PCR. Extracellular vesicles were isolated from cell culture supernatant by miRCURY Exosome Cell/Urine/CSF Kit (Qiagen) and RNA contained in extracellular vesicles was purified, analyzed in quality by Bioanalyzer (RNA nano) and evaluated by qPCR. The BrdU assay and caspase 3 were used to measure proliferation and apoptosis levels. Immunohistochemical expression of activated caspase-3 was used as a marker of apoptosis in RPTECs. Results By a whole-genome gene expression analysis, we found 107 genes specifically modulated by RPTECs in response to cisplatin and, among these, 30 genes induced by ARPCs following the cisplatin damage. In particular, we found a strong upregulation of the CYP1B1 gene (false discovery rate corrected p value <0.05; fold change=4,1). The qPCR confirmed the increase in CYP1B1 levels in the co-cultures with respect to the respective basal conditions (p <0.05). Interestingly, the CYP1B1 mRNA was also enveloped in Extracellular Vesicles released in the cell co-culture media by tARPC and RPTEC after cisplatin exposition. The CYP1B1 gene encodes a member of the cytochrome P450 superfamily of enzymes and the produced enzyme metabolizes procarcinogens, such as polycyclic aromatic hydrocarbons. CYP1B1 has been shown to be active within tumors and is also capable of metabolizing a structurally diverse range of anticancer drugs. It is responsible for the resistance to docetaxel, cisplatin, tamoxifen and nucleoside analogues. CYP1B1 is involved in the detoxification of the body by various exogenous toxic agents, including cisplatin. We found that CYP1B1 gene was expressed at low levels in RPTECs and in cisplatin-damaged RPTECs. Moreover, 96 h days after 2.5 μM exposure to cisplatin, RPTECs reduced the proliferation and underwent in apoptosis, as showed by caspase 3. However, in co-culture with ARPCs, ARPC cellular and extracellular vesicles CYP1B1 gene expression significantly increased, the apoptotic process was stopped and RPTECs increased their proliferation rate. These data support the hypothesis that ARPCs are sensor of cisplatin damaged-RPTEC and confers cisplatin resistance by transferring CYP1B1 gene in extracellular vesicles. Conclusion This is the first evidence of a cisplatin-induced overexpression of CYP1b1 in renal epithelial cells as a defense mechanism against cisplatin toxicity. This is consistent with our previous data showing that renal progenitors are resistant to cisplatin. The findings may have biological and clinical significance in terms of their implications in cellular communications and potential use of CYP1B1 as biomarkers for AKI induced by cisplatin or as protective agent.

P0563THE SHORT AND LONG-TERM EFFECTS OF HYPERTHERMIC INTRAPERITONEAL CHEMOTHERAPY ON RENAL FUNCTION IN PLATINUM-SENSITIVE RECURRENT OVARIAN CANCER

Abstract Background and Aims Cytoreductive surgery (CRS) with platinum based Hyperthermic Intraperitoneal Chemotherapy (HIPEC) represents a valid therapeutic approach in the treatment of ovarian cancer patients with peritoneal spread (vanDriel NEJM). Nevertheless, cisplatin nephrotoxicity represents one limitation to the diffusion of HIPEC in clinical practice. To date, few studies evaluated the nephrotoxicity of hyperthermic intraperitoneal cisplatin and the risk of acute kidney injury (AKI) in patients treated with HIPEC. The aim of our study is to evaluate short- and long-term changes in serum creatinine (SCr) levels in a cohort of patients with a first relapse of platinum-sensitive ovarian cancer, receiving CRS plus or minus HIPEC. Method We compared a cohort of patients with a first relapse of platinum-sensitive ovarian cancer, receiving CRS plus/minus HIPEC in a period from January 2013 to October 2018. The HIPEC technique required the perfusion of the abdominal cavity with a 4 L/m2 of a heated saline solution containing cisplatin 75 mg/m2. We assessed the estimated glomerular filtration rate (eGFR), using the CKD-EPI formula, and SCr from the preoperative value, at 24, 48, 72 hours, 7 days and the last SCr value available on the electronic record, at least 3 months after the procedure. We analyzed the effect of HIPEC treatment on SCr values over time and we used logistic regression models to investigate the effect of HIPEC treatment on clinical outcomes. No patient in the HIPEC group had kidney protective treatment with thiosulphate. Results Our analyses included complete data of 110 patients treated in our Institution from January 2013 to October 2018. The two groups had significant differences in baseline SCr (p-value = 0.002), with lower average values in the CRS+HIPEC group (mean 0.68, standard deviation [SD] 0.14 mg/dL) compared to the CRS group (mean 0.76, SD 0.13 mg/dL). The baseline eGFR was significantly higher in the CRS+HIPEC group (mean 95, SD 16 mL/min/1.73 m2) than in the CRS group (mean 88, SD 14 mL/min/1.73 m2) (p-value = 0.014) and three patients in each group had chronic kidney disease (CKD) before surgery. SCr values in the HIPEC group were significantly higher at post-operative day #7 (1.22 ± 1.10 mg/dL vs 0.69 ± 0.16 mg/dL; p-value <0.001) and the differences remained during follow-up at least three months after randomization (0.96 ± 0.55 vs 0.69 ± 0.19 mg/dL; p-value <0.001). Seventeen patients (31%) developed Acute Kidney Injury (AKI), according to the KDIGO Guidelines, in the first week after CRS+HIPEC versus seven patients (13%) after CRS alone. No patients who developed AKI post-HIPEC needed renal replacement treatment, although 5 (9%) had AKI stage III and 7 (13%) stage II. The CRS+HIPEC group had a significantly higher risk of developing AKI [OR: 3.48 (2.30-5.27)] compared with the CRS group (p-value <0.001). There were no statistically significant differences between the two groups with regard to risk of complications other than AKI. Conclusion To our knowledge, our study represents the first investigation on short- and long-term changes in SCr and on the risk of AKI in patients with a first relapse of platinum-sensitive ovarian cancer, treated with CRS and HIPEC. There is a strong correlation between the intraperitoneal cisplatin at elevated temperatures and the rise of SCr over the time. However, this event was no reversible and influenced following treatments in only eight women.

Does exercise training attenuate cisplatin nephrotoxicity?

Cisplatin (CP), a medication originating from the platinum has been used for solid cancers’ treatment in the last decade. CP is associated with numerous side effects as well. One of the side effects is nephrotoxicity. There are some types of procedure which can attenuate harmful effects of the drug, and the effectiveness of physical activity has been a controversial topic. It is well established that physical activity has positive effects on chronic kidney disease (CKD). The exercise training can modulate CP induced muscle wasting both in males and females. Although exercise training may have protective effect on renal function and the related risk factors, it cannot attenuate the renal injury resulted from CP therapy in females. The exercise training may improve interleukin 6 and heme oxygenase-1, reduces the production of CD4+T cell cytokines from the kidney, which play a major role in adaptive immune response. The present mini-review considered the effect of exercise training accompanied by the CP treatment.

Prevention of cisplatin nephrotoxicity (CN) in head and neck cancer patients receiving concurrent chemoradiation (CCRT) by adding oral rehydration solution (ORS) to short hydration regimen: A randomized open-label controlled trial.

e18560 Background: CN remains a frequent occurrence despite receiving standard fluid hydration, particularly for head and neck cancer patients undergoing CCRT. We aimed to investigate whether adding ORS to short hydration regimen can reduce CN. Methods: We conducted a randomized open-label controlled trial in patients with head and neck cancer receiving CCRT with 3-weekly cisplatin (≥ 60 mg/m²). Eligible patients were randomly assigned to receive short hydration regimen (2000 mL of normal saline on day 1) alone or in combination with 2000 mL of ORS on days -1, 2 and 3 of each cycle. All patients were instructed to drink at least 2000 mL of fluid. The primary end point was the incidence of ≥ gr 1 creatinine (Cr) elevation on day 8. The planned sample size was 160 (80 patients each arm). Results: Thirty-five patients in ORS group and 34 patients in control group (43% of planned sample size) were enrolled. Baseline characteristics were balanced between the two groups, except more patients in ORS group underwent surgery (35.3% vs. 22.9%), and had less feeding tube prophylaxis (76.5% vs. 88.6%), although there were not statistically significant. The mean dose of cisplatin on day 1 was significantly higher in ORS group (91.2 mg/m2 vs. 85.1 mg/m2, p=0.01). There was no difference of volume of total fluid intake and toxicities between the two groups. Less percentage of patients in ORS group developed ≥ gr 1 Cr elevation as shown in the Table, although there were not statistically significant. Conclusions: Although our interim analysis showed no significant difference of CN between the groups, there was a trend that addition of ORS might prevent acute and chronic kidney injury secondary to cisplatin. The completed enrollment is warranted to confirm this early findings. Clinical trial information: TCTR20200207005 . [Table: see text]

Angiotensin-Converting Enzyme Inhibitor Protects Against Cisplatin Nephrotoxicity by Modulating Kinin B1 Receptor Expression and Aminopeptidase P Activity in Mice.

Cisplatin is a highly effective chemotherapeutic agent. However, its use is limited by nephrotoxicity. Enalapril is an angiotensin I-converting enzyme inhibitor used for the treatment of hypertension, mainly through the reduction of angiotensin II formation, but also through the increase of kinins half-life. Kinin B1 receptor is associated with inflammation and migration of immune cells into the injured tissue. We have previously shown that the deletion or blockage of kinin B1 and B2 receptors can attenuate cisplatin nephrotoxicity. In this study, we tested enalapril treatment as a tool to prevent cisplatin nephrotoxicity. Male C57Bl/6 mice were divided into 3 groups: control group; cisplatin (20 mg/kg i.p) group; and enalapril (1.5 mg;kg i.p) + cisplatin group. The animals were treated with a single dose of cisplatin and euthanized after 96 h. Enalapril was able to attenuate cisplatin-induced increase in creatinine and urea, and to reduce tubular injury and upregulation of apoptosis-related genes, as well as inflammatory cytokines in circulation and kidney. The upregulation of B1 receptor was blocked in enalapril + cisplatin group. Carboxypeptidase M expression, which generates B1 receptor agonists, is blunted by cisplatin + enalapril treatment. The activity of aminopeptidase P, a secondary key enzyme able to degrade kinins, is restored by enalapril treatment. These findings were confirmed in mouse renal epithelial tubular cells, in which enalaprilat (5 μM) was capable of decreasing tubular injury and inflammatory markers. We treated mouse renal epithelial tubular cells with cisplatin (100 μM), cisplatin+enalaprilat and cisplatin+enalaprilat+apstatin (10 μM). The results showed that cisplatin alone decreases cell viability, cisplatin plus enalaprilat is able to restore cell viability, and cisplatin plus enalaprilat and apstatin decreases cell viability. In the present study, we demonstrated that enalapril prevents cisplatin nephrotoxicity mainly by preventing the upregulation of B1 receptor and carboxypeptidase M and the increased concentrations of kinin peptides through aminopeptidase activity restoration.

R-DHA-oxaliplatin (R-DHAOx) versus R-DHA-cisplatin (R-DHAP) regimen in B-cell lymphoma treatment: A eight-year trajectory study.

The R-DHAP regimen (rituximab, cisplatin, dexamethasone, and high-dose cytarabine) is standardly used to treat relapsed Non-Hodgkin lymphoma (NHL). Despite scarce data, cisplatin is frequently substituted with oxaliplatin (R-DHAOx) to avoid nephrotoxicity. We compared nephrotoxicity of cisplatin and oxaliplatin based on creatinine-based trajectory modeling. All patients with NHL treated by R-DHAP or R-DHAOx in Angers hospital between January 01, 2007, and December 31, 2014, were included. Patients received cisplatin 100mg/m2 or oxaliplatin 130mg/m2 (d1) with cytarabine (2000mg/m2 , two doses, d2), dexamethasone (40mg, d1-4), and rituximab (375mg/m2 , d1). Creatinine levels were recorded before each cycle. Individual profiles of trajectories were clustered to detect homogeneous patterns of evolution. Twenty-two patients received R-DHAP, 35 R-DHAOx, 6 switched from R-DHAP to R-DHAOx due to nephrotoxicity. Characteristics of patients were similar between two groups. Patients receiving R-DHAP experienced more severe renal injury than patients receiving R-DHAOx (68% vs. 7.7%, P<.001). Two homogeneous clusters appeared: cluster A, with a majority of R-DHAOx (32, 91.4%), was less nephrotoxic than B, with a majority of R-DHAP (19, 86.4%), with a decreased average serum creatinine level (P<.0001). There were no other differences between clusters. Our study confirms that R-DHAOx regimen causes less nephrotoxicity than R-DHAP regimen.

NGAL, albumin and cystatin C during cisplatin therapy.

Cisplatin is a commonly used chemotherapeutic drugs. It is known for its nephrotoxic side effects with an increased risk of acute kidney injury. Finding of clinically feasible cisplatin nephrotoxicity markers is of importance. In our study, we compared neutrophil gelatinase-associated lipocalin (NGAL) in serum and urine, the estimated glomerular filtration rate (based on serum cystatin C) and urine albumin as markers of nephrotoxicity. The study involved 11 men and 9 women (mean ± SD age 58.2±9.5 years) with different malignancies treated with cisplatin in four cycles of chemotherapy (I - IV). Samples 0-4 were taken before, immediately after, in 3, 6 and 24 hours after administering chemotherapy. We detected significant increase of ACR in Sample 2 (p=0.03) and decrease of eGFR in Sample 4 (p=0.03) up to 24 hours after cisplatin administration in the first chemotherapy cycle only. When cumulative effect of cisplatin was assessed, significantly increased values of urine albumin (vs cycle I) were found in Sample 0 (p=0.00058), 1 (p=0.00256), 2 (p=0.00456), 3 (p=0.00006) and 4 (p=0.00319) in cycles II to IV. We found a correlation between values of urine NGAL and urine albumin (r=0.68, p<0.0001). In conclusion, urine albumin was the only measured marker that consistently and statistically significantly increased after cisplatin containing chemotherapy cycles.

Protein Kinase C-δ Mediates Kidney Tubular Injury in Cold Storage-Associated Kidney Transplantation.

Kidney injury associated with cold storage is a determinant of delayed graft function and the long-term outcome of transplanted kidneys, but the underlying mechanism remains elusive. We previously reported a role of protein kinase C-δ (PKCδ) in renal tubular injury during cisplatin nephrotoxicity and albumin-associated kidney injury, but whether PKCδ is involved in ischemic or transplantation-associated kidney injury is unknown. To investigate PKCδ's potential role in injury during cold storage-associated transplantation, we incubated rat kidney proximal tubule cells in University of Wisconsin (UW) solution at 4°C for cold storage, returning them to normal culture medium at 37°C for rewarming. We also stored kidneys from donor mice in cold UW solution for various durations, followed by transplantation into syngeneic recipient mice. We observed PKCδ activation in both in vitro and in vivo models of cold-storage rewarming or transplantation. In the mouse model, PKCδ was activated and accumulated in mitochondria, where it mediated phosphorylation of a mitochondrial fission protein, dynamin-related protein 1 (Drp1), at serine 616. Drp1 activation resulted in mitochondrial fission or fragmentation, accompanied by mitochondrial damage and tubular cell death. Deficiency of PKCδ in donor kidney ameliorated Drp1 phosphorylation, mitochondrial damage, tubular cell death, and kidney injury during cold storage-associated transplantation. PKCδ deficiency also improved the repair and function of the renal graft as a life-supporting kidney. An inhibitor of PKCδ, δV1-1, protected kidneys against cold storage-associated transplantation injury. These results indicate that PKCδ is a key mediator of mitochondrial damage and renal tubular injury in cold storage-associated transplantation and may be an effective therapeutic target for improving renal transplant outcomes.

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.

Retinoic acid receptor-beta prevents cisplatin-induced proximal tubular cell death

Cisplatin's toxicity in renal tubular epithelial cells limits the therapeutic efficacy of this antineoplastic drug. In cultured human proximal tubular HK-2 cells (PTC) a prostaglandin uptake transporter (PGT)-dependent increase in intracellular prostaglandin E2 (iPGE2) mediates cisplatin's toxicity (i.e. increased cell death and loss of cell proliferation) so that it is prevented by PGT inhibitors. Here we found in cisplatin-treated PTC that 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS), a PGT inhibitor, prevented cisplatin's toxicity but not the increase in iPGE2. Because expression of retinoic acid receptor-β (RAR-β) is dependent on iPGE2 and because RAR-β is a regulator of cell survival and proliferation, we hypothesized that RAR-β might mediate the protective effect of DIDS against cisplatin's toxicity in PTC. Our results confirmed this hypothesis because: i) protection of PTC by DIDS was abolished by RAR-β antagonist LE-135; ii) DIDS increased the expression of RAR-β in PTC and prevented its decrease in cisplatin-treated PTC but not in cisplatin-treated human cervical adenocarcinoma HeLa cells in which DIDS failed to prevent cisplatin's toxicity; iii) while RAR-β expression decreased in cisplatin-treated PTC, RAR-β over-expression prevented cisplatin's toxicity. RAR-β agonist CH55 or RAR pan-agonist all-trans retinoic acid did not prevent cisplatin's toxicity, which suggests that RAR-β does not protect PTC through activation of gene transcription. In conclusion, RAR-β might be a new player in cisplatin-induced proximal tubular injury and the preservation of its expression in proximal tubules through treatment with DIDS might represent a novel strategy in the prevention of cisplatin's nephrotoxicity without compromising cisplatin's chemotherapeutic effect on cancer cells.

SIRT2 is involved in cisplatin-induced acute kidney injury through regulation of mitogen-activated protein kinase phosphatase-1.

Activation of mitogen-activated protein kinase phosphatase-1 (MKP-1), a dual-specificity protein phosphatase, regulates mitogen-activated protein kinase signaling. C-Jun N-terminal kinase (JNK) and p38 are activated in cisplatin-induced renal injury. However, the change of MKP-1 expression in cisplatin-induced renal injury and the regulatory effect of sirtuin 2 (SIRT2), a nicotinamide adenine dinucleotide-dependent deacetylase, on MKP-1 remains unknown. To address these issues, we used constitutional Sirt2 knockout (KO) mice, transgenic (TG) mice with increased expression of SIRT2 specifically in proximal tubular epithelial cellsand wild-type (WT) mice. Cisplatin nephrotoxicity was induced by intraperitoneal injection of cisplatin. MKP-1 expression in the kidney was decreased after cisplatin treatment. Cisplatin-induced downregulation of MKP-1 was reversed in Sirt2 KO mice kidney and further decreased in Sirt2 TG mice kidney. We observed similar phenomenon with SIRT2-knockdown or SIRT2-overexpressed tubular epithelial cells. Phosphorylation of p38 and JNK, a downstream signal pathway of MKP-1, increased in WT mice kidney following treatment with cisplatin. A decrease in SIRT2 suppressed cisplatin-induced phosphorylation of p38 and JNK in kidney and tubular epithelial cells. Overexpression of SIRT2 further increased phosphorylation of p38 and JNK in kidney and tubular epithelial cells. Acetylation of MKP-1 was significantly increased in SIRT2-knockdown cells and decreased in SIRT2-overexpressed cells after cisplatin stimulation. Sirt2 KO mice and Sirt2 TG mice showed amelioration and aggravation of renal injury, apoptosis, necroptosis and inflammation induced by cisplatin. Our data show that SIRT2 is associated with cisplatin-induced renal injury through regulation of MKP-1 expression.

FDA‐approved PARP Inhibitors are Cytoprotective against Cisplatin Injury in Renal Proximal Tubular Cells

Cisplatin is a potent chemotherapeutic drug used to treat many solid cancers. However, its dose‐limiting side effect is nephrotoxicity, leading to acute kidney injury and chronic kidney disease. We previously reported that genetic or pharmacologicial inhibition of poly (ADP‐ribose) polymerase 1 (PARP1) protects against cisplatin nephrotoxicity.PARP1 inhibitors including olaparib, niraparib, and rucaparib are currently FDA approved for treatment of ovarian cancer. In this study, we tested the effect of the above FDA‐approved PARP inhibitors in cisplatin nephrotoxicity. Human HK‐2, pig LLC‐PK1, and mouse HUMPT renal proximal tubular cells (PTC) were subjected to one cycle of treatment with high‐dose cisplatin (1 to 1.5 mM) or four cycles of treatment with low‐dose cisplatin (1 to 3 μM). Each cycle consisted of 6 hours of treatment with cisplatin and 18 hours of recovery in cisplatin‐free medium. The FDA‐approved PARP inhibitors (300 pM to 1 μM) or the same volume of dimethylformamide (vehicle) were added immediately before the first treatment cycle and incubated continuously. The 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay performed to determine cell viability, lactate dehydrogenase (LDH) release assay to determine cell membrane disruption, and propidium iodide (PI) staining to determine necrotic cell death.All of the PARP inhibitors improved cell viability after the high‐dose cisplatin treatment in renal PTC. Increased percentages of LDH release and PI‐positive cells observed after one cycle of treatment with high‐dose cisplatin were significantly abrogated by the PARP inhibitors. Moreover, combined treatment with the PARP inhibitors showed an additive effect on cell viability in renal PTC treated with high‐dose cisplatin. The PARP inhibitors also enhanced cell viability after the four cycles of treatment with low‐dose cisplatin in renal PTC.Thus, our findings suggest that the FDA‐approved PARP inhibitors can protect efficaciously against death of PTC during cisplatin nephrotoxicity and could be developed as potential therapeutic agents to improve cisplatin nephrotoxicity.Support or Funding InformationThis study is supported by NIH grants DK‐116987, DK‐120533, AHA grants 15GRNT25080031 (BJP), 15POST25130003 (HSJ), and NRF grant NRF‐2019R1F1A1041410 (JK).

Ribociclib mitigates cisplatin-associated kidney injury through retinoblastoma-1 dependent mechanisms

Aberrant cell cycle activation is a hallmark of carcinogenesis. Recently three cell cycle targeting cyclin-dependent kinase 4/6 (CDK4/6) inhibitors have been approved for the treatment of metastatic breast cancer. CDK4/6 inhibitors suppress proliferation through inhibition of CDK4/6-dependent retinoblastoma-1 (Rb1) phosphorylation and inactivation, a key regulatory step in G1-to-S-phase transition. Importantly, aberrant cell cycle activation is also linked with several non-oncological diseases including acute kidney injury (AKI). AKI is a common disorder caused by toxic, inflammatory, and ischemic damage to renal tubular epithelial cells (RTECs). Interestingly, AKI triggered by the anti-cancer drug cisplatin can be mitigated by ribociclib, a CDK4/6 inhibitor, through mechanisms that remain unclear. Employing in vivo cell cycle analysis and functional Rb1 knock-down, here, we have examined the cellular and pharmacological basis of the renal protective effects of ribociclib during cisplatin nephrotoxicity. Remarkably, siRNA-mediated Rb1 silencing or RTEC-specific Rb1 gene ablation did not alter the severity of cisplatin-associated AKI; however, it completely abrogated the protective effects conferred by ribociclib administration. Furthermore, we find that cisplatin treatment evokes CDK4/6 activation and Rb1 phosphorylation in the normally quiescent RTECs, however, this is not followed by S-phase entry likely due to DNA-damage induced G1 arrest. The cytoprotective effects of ribociclib are thus not a result of suppression of S-phase entry but are likely dependent on the maintenance of Rb1 in a hypo-phosphorylated and functionally active form under stress conditions. These findings delineate the role of Rb1 in AKI and illustrate the pharmacological basis of the renal protective effects of CDK4/6 inhibitors.

Cisplatin nephrotoxicity is induced via poly(ADP-ribose) polymerase activation in adult zebrafish and mice.

Cisplatin is a well-known chemotherapy medication used to treat numerous cancers. However, treatment with cisplatin in cancer therapy has major side effects, such as nephrotoxic acute kidney injury. Adult vertebrate kidneys are commonly used as models of cisplatin-induced nephrotoxic acute kidney injury. Embryonic zebrafish kidney is more simplified and is composed simply of two nephrons and thus is an excellent model for the investigation of cisplatin nephrotoxicity. Here, we developed a novel model to induce cisplatin nephrotoxicity in adult zebrafish and demonstrated that intraperitoneal injection of cisplatin caused a decline in kidney proximal tubular function based on fluorescein-labeled dextran uptake and alkaline phosphatase staining. We also showed that cisplatin induced histological injury of the kidney tubules, quantified by tubular injury scores on the periodic acid-Schiff-stained kidney sections. As shown in a mouse model of cisplatin-induced nephrotoxicity, the activation of poly(ADP-ribose) polymerase (PARP), an enzyme implicated in cisplatin-induced cell death, was markedly increased after cisplatin injection in adult zebrafish. Furthermore, pharmacological inhibition of PARP using a specific PARP inhibitor PJ 34 hydrochloride (PJ34) or 3-aminobenzamide ameliorated kidney proximal tubular functional and histological damages in cisplatin-injected adult zebrafish kidneys. Administration of a combination of PARP inhibitors PJ34 and 3-aminobenzamide additively protected renal function and histology in zebrafish and mouse models of cisplatin nephrotoxicity. In conclusion, these data suggest that adult zebrafish are not only suitable for drug screening and genetic manipulation but also useful as a simplified but powerful model to study the pathophysiology of cisplatin nephrotoxicity and establish new therapies for treating human kidney diseases.

Risk factors for renal toxicity after inpatient cisplatin administration

BackgroundAfter several decades, cisplatin continues to be an essential drug for the treatment of several tumors, however, its potential nephrotoxicity is still a clinically relevant issue. Identification of predisposing factors for renal toxicity could be of value to warrant prophylactic measures.MethodsWe analyzed data from 198 patients with various tumor types, treated with cisplatin containing regimens in our regional cancer center in a two-years period. Assessed variables included age, gender, smoking status, alcohol consumption, tumor type, prior or concomitant anticancer treatment, cisplatin dose, time-interval between cycles, number of cycles, concomitant nephrotoxic drugs or radiotherapy and co-morbidities. We divided cisplatin nephrotoxicity in two categories: transient and permanent. Univariable and multivariable analyses were performed in order to define statistical associations.ResultsCisplatin discontinuation rate was 27,7%, of which, 8.1% was due to renal toxicity. A total of 74 and 21 patients developed transient and permanent nephrotoxicity, respectively. At univariable analysis cirrhosis (p = 0.027), hypertension (p = 0.020), alcohol intake (p = 0.030) and number of cycles < 4 (p = 0.002) were significantly associated with transient renal toxicity, while at the multivariable analysis, a statistical significance was detected for cirrhosis (p = 0.009), hypertension (p = 0.009) and a total number of cycles < 4 (p = 0.003). Regarding permanent renal toxicity, a concomitant administration of NSAIDs was significant at univariable analysis (p = 0.002).ConclusionsRelevant risk factors for the development of transient nephrotoxicity were defined. Patients presenting these baseline characteristics may require more frequent post-cycle check-up visits and hydration treatment should be guaranteed as soon as a reduction of creatinine clearance is detected.

Impaired Tubular Reabsorption Is the Main Mechanism Explaining Increases in Urinary NGAL Excretion Following Acute Kidney Injury in Rats.

Neutrophil gelatinase-associated lipocalin (NGAL) is a secreted low-molecular weight iron-siderophore-binding protein. NGAL overexpression in injured tubular epithelia partly explains its utility as a sensitive and early urinary biomarker of acute kidney injury (AKI). Herein, we extend mechanistic insights into the source and kinetics of urinary NGAL excretion in experimental AKI. Three models of experimental AKI were undertaken in adult male Wistar rats; renal ischemia-reperfusion injury (IRI) and gentamicin (G) and cisplatin (Cisp) nephrotoxicity. Alongside standard histological and biochemical assessment of AKI, urinary NGAL excretion rate, plasma NGAL concentration, and renal NGAL mRNA/protein expression were assessed. In situ renal perfusion studies were undertaken to discriminate direct shedding of NGAL to the urine from addition of NGAL to the urine secondary to alterations in the tubular handling of glomerular filtrate-derived protein. Renal NGAL expression and urinary excretion increased in experimental AKI. In acute studies in both the IRI and G models, direct renal perfusion with Kreb's buffer eliminated urinary NGAL excretion. Addition of exogenous NGAL to the Kreb's buffer circuit, reestablishment of perfusion with systemic blood or reperfusion with renal vein effluent restored high levels of urinary NGAL excretion. Urinary NGAL excretion in AKI arises in large proportion from reduced reabsorption from the glomerular filtrate. Hence, subclinical cellular dysfunction could increase urinary NGAL, particularly in concert with elevations in circulating prerenal NGAL and/or pharmacological inhibition of tubular reabsorption. More granular interpretation of urinary NGAL measurements could optimize the scope of its clinical utility as a biomarker of AKI.