Diallyl trisulfide and its active metabolite allyl methyl sulfone attenuate cisplatin-induced nephrotoxicity by inhibiting the ROS/MAPK/NF-κB pathway

Cisplatin, a chemotherapy medication employed in the treatment of various solid tumors, is constrained in its clinical application due to nephrotoxicity. Diallyl trisulfide (DATS), a compound derived from garlic that possessed anticancer and antioxidant properties, can be combined with cisplatin without hindering its antitumor effects. The present investigation examined the defensive properties of DATS and its active metabolites against renal dysfunction caused by cisplatin. We created a mouse model to study renal injury caused by cisplatin and assessed kidney histology, immunochemistry, and serum cytokines. DATS treatment effectively reduced the pathological changes caused by cisplatin by decreasing the levels of renal function markers BUN, CRE, cystatin C, NGAL, inflammatory factors TNF-α, IL-6, and the protein expression of α-SMA, NF-κB, KIM-1. A pharmacokinetic evaluation of DATS found that allyl methyl sulfone (AMSO2) was the most abundant and persistent metabolite of DATS in vivo. Then, we examined the impact of AMSO2 on cell viability, apoptosis, ROS generation, and MAPK/NF-κB pathways in HK-2 cells treated with cisplatin. Cotreatment with AMSO2 effectively hindered the HK-2 cells alterations induced by cisplatin. Furthermore, AMSO2 mitigated oxidative stress through the modulation of MAPK and NF-κB pathways. Our findings indicated that DATS and its active derivative AMSO2 attenuated cisplatin-induced nephrotoxicity. DATS shows potential as a viable treatment for nephrotoxicity caused by cisplatin.

Urinary TIMP-2*IGFBP-7 to diagnose acute kidney injury in children receiving cisplatin

BACKGROUND

Cisplatin is associated with acute kidney injury (AKI) and electrolyte abnormalities. Urine tissue inhibitor of metalloproteinase 2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP-7) may be early cisplatin-AKI biomarkers.

METHODS

We conducted a 12-site prospective cohort study with pediatric patients treated with cisplatin (May 2013-December 2017). Blood and urine (measured for TIMP-2, IGFBP-7) were collected pre-cisplatin, 24-h post-cisplatin, and near hospital discharge during the first or second cisplatin cycle (early visit (EV)) and during second-to-last or last cisplatin cycle (late visit (LV)).

PRIMARY OUTCOME

serum creatinine (SCr)-defined AKI (≥ stage 1).

RESULTS

At EV (median (interquartile (IQR)) age: 6 (2-12) years; 78 (50%) female), 46/156 (29%) developed AKI; at LV, 22/127 (17%) experienced AKI. At EV, TIMP-2, IGFBP-7, and TIMP-2*IGFBP-7 pre-cisplatin infusion concentrations were significantly higher in participants with vs. those without AKI. At EV and LV, biomarker concentrations were significantly lower in participants with vs. those without AKI at post-infusion and near-hospital discharge. Biomarker values normalized to urine creatinine were higher in patients with AKI compared to without (LV post-infusion, median (IQR): TIMP-2*IGFBP-7: 0.28 (0.08-0.56) vs. 0.04 (0.02-0.12) (ng/mg creatinine)2/1000; P < .001). At EV, pre-infusion biomarker concentrations had the highest area under the curves (AUC) (range: 0.61-0.62) for AKI diagnosis; at LV, biomarkers measured post-infusion and near discharge yielded the highest AUCs (range: 0.64-0.70).

CONCLUSIONS

TIMP-2*IGFBP-7 were poor to modest at detecting AKI post-cisplatin. Additional studies are needed to determine whether raw biomarker values or biomarker values normalized to urinary creatinine are more strongly associated with patient outcomes. A higher resolution version of the Graphical abstract is available as Supplementary information.

Cisplatin Nephrotoxicity: Novel Insights Into Mechanisms and Preventative Strategies

Cisplatin is a highly effective chemotherapeutic agent that has been used for more than 50 years for a variety of cancers; however, its use is limited by toxicity, including nephrotoxicity. In this in-depth review, we discuss the incidence of cisplatin-associated acute kidney injury, as well as common risk factors for its development. Cisplatin accumulates in the kidney tubules and causes AKI through various mechanisms, including DNA damage, oxidative stress, and apoptosis. We also discuss the spectrum of nephrotoxicity, including acute and chronic impairment of kidney function, electrolyte disturbances, and thrombotic microangiopathy. We discuss the limited options for the diagnosis, prevention, and management of these complications, along with factors that may impact future therapy with or without cisplatin. We conclude with directions for future research in this expanding and important area.

Acute kidney injury during cisplatin therapy and associations with kidney outcomes 2 to 6 months post-cisplatin in children: a multi-centre, prospective observational study

BACKGROUND

Few studies describe acute kidney injury (AKI) burden during paediatric cisplatin therapy and post-cisplatin kidney outcomes. We determined risk factors for and rate of (1) AKI during cisplatin therapy, (2) chronic kidney disease (CKD) and hypertension 2-6 months post-cisplatin, and (3) whether AKI is associated with 2-6-month outcomes.

METHODS

This prospective cohort study enrolled children (aged < 18 years at cancer diagnosis) treated with cisplatin from twelve Canadian hospitals. AKI during cisplatin therapy (primary exposure) was defined based on Kidney Disease: Improving Global Outcomes (KDIGO) serum creatinine criteria (≥ stage one). Severe electrolyte abnormalities (secondary exposure) included ≥ grade three hypophosphatemia, hypokalemia, or hypomagnesemia (National Cancer Institute Common Terminology Criteria for Adverse Events v4.0). CKD was albuminuria or decreased kidney function for age (KDIGO guidelines). Hypertension was defined based on the 2017 American Academy of Pediatrics guidelines.

RESULTS

Of 159 children (median [interquartile range [IQR]] age: 6 [2-12] years), 73/159 (46%) participants developed AKI and 55/159 (35%) experienced severe electrolyte abnormalities during cisplatin therapy. At median [IQR] 90 [76-110] days post-cisplatin, 53/119 (45%) had CKD and 18/128 (14%) developed hypertension. In multivariable analyses, AKI was not associated with 2-6-month CKD or hypertension. Severe electrolyte abnormalities during cisplatin were associated with having 2-6-month CKD or hypertension (adjusted odds ratio (AdjOR) [95% CI]: 2.65 [1.04-6.74]). Having both AKI and severe electrolyte abnormalities was associated with 2-6-month hypertension (AdjOR [95% CI]: 3.64 [1.05-12.62]).

CONCLUSIONS

Severe electrolyte abnormalities were associated with kidney outcomes. Cisplatin dose optimization to reduce toxicity and clear post-cisplatin kidney follow-up guidelines are needed. A higher resolution version of the Graphical abstract is available as Supplementary information.

The combination of G-CSF and AMD3100 mobilizes bone marrow-derived stem cells to protect against cisplatin-induced acute kidney injury in mice

BACKGROUND

Several studies have confirmed that mobilizing bone marrow-derived stem cells (BMSCs) ameliorates renal function loss following cisplatin-induced acute kidney injury (AKI). The aim of this study was to explore whether the combination of granulocyte-colony stimulating factor (G-CSF) and plerixafor (AMD3100) exerts beneficial effects on renal function recovery in a model of cisplatin-induced nephrotoxicity.

METHODS

C57BL/6J mice received intraperitoneal injections of G-CSF (200 μg/kg/day) for 5 consecutive days. On the day of the last injection, the mice received a single subcutaneous dose of AMD3100 (5 mg/kg) 1 h before cisplatin 20 mg/kg injection. Ninety-six hours after cisplatin injection, the mice were euthanized, and blood and tissue samples were collected to assess renal function and tissue damage. Cell mobilization was assessed by flow cytometry (FCM).

RESULTS

Mice pretreated with G-CSF/AMD3100 exhibited longer survival and lower serum creatinine and blood urea nitrogen (BUN) levels than mice treated with only G-CSF or saline. Combinatorial G-CSF/AMD3100 treatment attenuated tissue injury and cell death, enhanced cell regeneration, and mobilized a higher number of stem cells in the peripheral blood than G-CSF or saline treatment. Furthermore, the mRNA expression of proinflammatory factors was lower, whereas that of anti-inflammatory factors was higher, in the G-CSF/AMD3100 group than in the G-CSF or saline group (all P < 0.05).

CONCLUSIONS

These results suggest that combinatorial G-CSF/AMD3100 therapy mobilizes BMSCs to accelerate improvements in renal functions and prevent cisplatin-induced renal tubular injury. This combinatorial therapy may represent a new therapeutic option for the treatment of AKI and should be further investigated in the future.

Amlodipine alleviates cisplatin-induced nephrotoxicity in rats through gamma-glutamyl transpeptidase (GGT) enzyme inhibition, associated with regulation of Nrf2/HO-1, MAPK/NF-κB, and Bax/Bcl-2 signaling

BACKGROUND

The therapeutic utility of the effective chemotherapeutic agent cisplatin is hampered by its nephrotoxic effect. We aimed from the current study to examine the possible protective effects of amlodipine through gamma-glutamyl transpeptidase (GGT) enzyme inhibition against cisplatin nephrotoxicity.

METHODS

Amlodipine (5 mg/kg, po) was administered to rats for 14 successive days. On the 10th day, nephrotoxicity was induced by a single dose of cisplatin (6.5 mg/kg, ip). On the last day, blood samples were collected for estimation of kidney function, while kidney samples were used for determination of GGT activity, oxidative stress, inflammatory, and apoptotic markers, along with histopathological evaluation.

RESULTS

Amlodipine alleviated renal injury that was manifested by significantly diminished serum creatinine and blood urea nitrogen levels, compared to cisplatin group. Amlodipine inhibited GGT enzyme, which participates in the metabolism of extracellular glutathione (GSH) and platinum-GSH-conjugates to a reactive toxic thiol. Besides, amlodipine diminished mRNA expression of NADPH oxidase in the kidney, while enhanced the anti-oxidant defense by activating Nrf2/HO-1 signaling. Additionally, it showed marked anti-inflammatory response by reducing expressions of p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor-kappa B (NF-κB), with subsequent down-regulation of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and vascular cell adhesion molecule-1 (VCAM-1). Moreover, amlodipine reduced Bax/Bcl-2 ratio and elevated hepatocyte growth factor (HGF), thus favoring renal cell survival.

CONCLUSIONS

Effective GGT inhibition by amlodipine associated with enhancement of anti-oxidant defense and suppression of inflammatory signaling and apoptosis support our suggestion that amlodipine could replace toxic GGT inhibitors in protection against cisplatin nephrotoxicity.

Wnt/β-catenin agonist BIO alleviates cisplatin-induced nephrotoxicity without compromising its efficacy of anti-proliferation in ovarian cancer

AIMS

Cisplatin is an anticancer agent marred by nephrotoxicity. Limiting this adverse effect may allow the use of higher doses to improve its efficacy. The Wnt/β-catenin signaling pathway plays a critical role in nephrogenesis and repair of renal diseases. BIO, a small molecule agonist of this pathway, exerted a protective effect in adriamycin nephropathy and promoted nephrogenesis. The aim of this study, therefore, was to investigate whether Wnt/β-catenin agonist BIO could protect against cisplatin-induced nephrotoxicity in vivo and in vitro, as well as its possible mechanism.

MAIN METHODS

Male mice and human renal proximal tubular cells (HK-2) were subjected to cisplatin to study reno-protective effect of BIO. Renal function, cell viability, tubular apoptosis, production of reactive oxygen species (ROS) and proliferative level were analyzed respectively. Additionally, xenograft model was induced to investigate if BIO would impair the antitumor effect of cisplatin.

KEY FINDINGS

Cisplatin increased serum creatinine levels and promoted histological renal injury as well as oxidative stress levels. Besides, renal apoptotic level and the expression of pro-apoptotic proteins, Bax/bcl-2 and cleaved-caspase3 included, in the kidney were increased. All these features were decreased by BIO, which also activated Wnt/β-catenin pathway in cisplatin-induced nephrotoxicity. Similarly, accompanied by the motivation of Wnt/β-catenin pathway, BIO exerted a positively protective effect on HK-2 challenged cisplatin. Last, the chemotherapeutic effects of cisplatin in xenograft mice of ovary tumor models and in lung cancer cells weren't compromised by BIO.

SIGNIFICANCE

Wnt/β-catenin agonist BIO has the potential to prevent cisplatin nephrotoxicity without compromising its anti-proliferation efficacy.

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.

Benzbromarone mitigates cisplatin nephrotoxicity involving enhanced peroxisome proliferator-activated receptor-alpha (PPAR-α) expression

AIM

Despite the great efficacy reported for cisplatin as a widely used chemotherapeutic agent, its clinical use is limited by the challenge of facing its serious side effect; nephrotoxicity. In this study, the effect of the benzbromarone on peroxisome proliferator-activated receptor-alpha (PPAR-α) was investigated against cisplatin nephrotoxicity.

MAIN METHODS

Rats were administered benzbromarone (10 mg/kg/day; p.o.) for 14 days, and cisplatin (6.5 mg/kg; i.p.) as a single dose on the 10th day. Blood and kidney tissue samples were collected for determination of kidney function, biochemical and molecular markers, as well as histopathological investigation.

KEY FINDINGS

Benzbromarone improved kidney function, that was evidenced by reduced serum creatinine and blood urea nitrogen to nearly the half, compared to the group administered cisplatin alone. The protein expression of PPAR-α was enhanced with benzbromarone treatment, along with a considerable suppression of oxidative stress as benzbromarone reduced mRNA expression of NADPH oxidase, while increased the anti-oxidant HO-1 protein expression associated with enhancing Nrf2. Besides, it displayed a marked anti-inflammatory effect involved suppression of p38 MAPK/NF-κB p65 signaling pathway and its downstream targets. Moreover, benzbromarone retarded apoptosis associated with reducing the pro-apoptotic (Bax) and enhancing the anti-apoptotic (Bcl-2) protein expressions. The protective effects of benzbromarone were also confirmed by histopathological results.

SIGNIFICANCE

Our data confirm the relation between PPAR-α, and the deleterious effects induced by cisplatin. It can also be suggested that enhancing PPAR-α expression by benzbromarone is a promising therapeutic approach that overcomes cisplatin nephrotoxicity, involving regulation of different signaling pathways: Nrf2/HO-1, p38 MAPK/NF-κB p65, and Bax/Bcl-2.

Hexapeptide derived from prothymosin alpha attenuates cisplatin-induced acute kidney injury

BACKGROUND

Prothymosin alpha (ProTα) is a nuclear protein expressed in virtually all mammalian tissues. Previous studies have shown that ProTα exhibits protective effects against ischemia-induced cell death in various cell types. Recently, the 6-residue peptide P₆Q (NEVDQE), the modified form of the active 6-residue core (51-56) in ProTα, has also been shown to have protective effects against retinal ischemia. However, it remains to be elucidated whether P₆Q is effective against acute kidney injury (AKI). Therefore, we investigated the renoprotective effect of P₆Q on cisplatin-induced AKI.

METHODS

Cultured HK-2 cells were treated with cisplatin for 24 h and pretreatment with ProTα or P₆Q was carried out 30 min before cisplatin treatment. Cell viability was evaluated using the MTT assay. In an in vivo study, 8-week-old male Wistar rats were divided into control, cisplatin treated, and cisplatin treated with P₆Q injection groups. In the last of these, P₆Q was injected intravenously before cisplatin treatment. Then, we evaluated the renoprotective effect of P₆Q.

RESULTS

In the study on cultured cells, pretreatment with ProTα or P₆Q prevented cisplatin-induced cell death. In the in vivo study, pretreatment with P₆Q significantly attenuated cisplatin-induced increase in serum creatinine and blood urea nitrogen levels, renal tubular cell injury, and apoptosis. Moreover, P₆Q attenuated the mitochondrial apoptotic pathway and accelerated Akt phosphorylation after cisplatin-induced renal damage.

CONCLUSION

Taken together, our findings indicate that P₆Q can attenuate cisplatin-induced AKI and suppress the mitochondrial apoptotic pathway via Akt phosphorylation. These data suggest that P₆Q has potential as a preventative drug for cisplatin-induced AKI.

Tetramethylpyrazine guards against cisplatin-induced nephrotoxicity in rats through inhibiting HMGB1/TLR4/NF-κB and activating Nrf2 and PPAR-γ signaling pathways

Cisplatin-induced acute renal injury is the most common and serious side effect, sometimes requiring discontinuation of the treatment. Thus, the development of new protective strategies is essential. The present study aimed to investigate the potential nephroprotective effect of tetramethylpyrazine (TMP) against acute renal damage induced by cisplatin in rats. Rats were administered 50 and 100 mg/kg TMP intraperitoneally before cisplatin (7 mg/kg). Acute nephrotoxicity was evident in cisplatin-treated rats where relative kidney weight, BUN and serum creatinine were markedly elevated. Cisplatin administration resulted in enhanced oxidative stress, evidenced by depleted GSH level as well as catalase and superoxide dismutase activities. Also, lipid peroxidation was boosted in comparison to the control. This was associated with inhibition of Nrf2 defense pathway. Moreover, cisplatin increased the expression of pro-inflammatory mediators in the kidney tissues. Cisplatin-induced apoptosis was depicted by elevated Bax mRNA expression and caspase-3 activity, as well as decreased Bcl2 mRNA expression. In addition, high mobility group box 1/toll-like receptor 4/nuclear factor-kappa B (HMGB1/TLR4/NF-κB) signaling pathway was significantly upregulated, while peroxisome proliferator-activated receptor-gamma (PPAR-γ) expression was significantly diminished in cisplatin-treated rats. Cisplatin-induced nephrotoxicity, oxidative stress, inflammation, apoptosis and the effect on Nrf2 defense pathway and HMGB1/TLR4/NF-κB as well as PPAR-γ expression were markedly ameliorated by TMP administration. Given the major nephrotoxicity of cisplatin cancer chemotherapy, TMP might be a potential candidate for neoadjuvant chemotherapy due to its antioxidant, anti-inflammatory and anti-apoptotic effects, in addition to its effect on Nrf2, HMGB1/TLR4/NF-κB signaling pathway and PPAR-γ expression.

Renal protective effect of polysulfide in cisplatin-induced nephrotoxicity

Cisplatin is a major chemotherapeutic drug for solid tumors whereas it may lead to severe nephrotoxicity. Despite decades of efforts, effective therapies remain largely lacking for this disease. In the current research, we investigated the therapeutic effect of hydrogen polysulfide, a novel hydrogen sulfide (H2S) derived signaling molecule, in cisplatin nephrotoxicity and the mechanisms involved. Our results showed that polysulfide donor Na2S4 ameliorated cisplatin-caused renal toxicity in vitro and in vivo through suppressing intracellular reactive oxygen species (ROS) generation and downstream mitogen-activated protein kinases (MAPKs) activation. Additionally, polysulfide may inhibit ROS production by simultaneously lessening the activation of NADPH oxidase and inducing nucleus translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) in RPT cells. Interestingly, polysulfide possesses anti-cancer activity and is able to add on more anti-cancer effect to cisplatin in non-small cell lung cancer (NSCLC) cell lines. Moreover, we observed that the number of sulfur atoms in polysulfide well reflected the efficacy of these molecules not only in cell protection but also cancer inhibition which may serve as a guide for further development of polysulfide donors for pharmaceutical usage. Taken together, our study suggests that polysulfide may be a novel and promising therapeutic agent to prevent cisplatin-induced nephrotoxicity.

Changes in the serum, liver, and renal cortical lipids and electrolytes in rabbits with cisplatin-induced nephrotoxicity

BACKGROUND/AIM

Cisplatin is an anticancer drug that can induce nephrotoxicity. Its toxicity is associated with dyslipidemia and disturbed electrolyte balance. In the present study we investigated the changes in serum lipid profile and electrolyte levels and their contents in kidney and liver tissues of rabbits treated with cisplatin.

MATERIALS AND METHODS

Twenty-eight adult male New Zealand White rabbits were used in the experiment. Animals of groups C, P1, and P2 were injected with saline, cisplatin (4.0 mg/kg bw), and cisplatin (6.5 mg/kg bw), respectively, and killed 3 days after the injections. Animals of group R were given cisplatin (6.5 mg/kg bw) and killed after 7 days. All animals were killed after an overnight fast.

RESULTS

The P2 animals showed reductions in their body weights, significant (P < 0.001) increases in serum creatinine and urea levels, and significant (P < 0.001) drops in cortical alkaline phosphatase activity and necrotic kidney histology. The treatments had no effect on liver function. Moreover, the P2 animals showed increased serum cholesterol, TAG, and elevated LDL-cholesterol, with significant accumulations of the kidney cholesterol and TAG, but no change in serum phospholipid and depleted hepatic cholesterol. Moreover, the P2 animals had depressed serum levels of potassium, calcium, and magnesium, and reduced renal cortical calcium and magnesium contents and depressed liver calcium but not magnesium. However, the P1 animals had no significant alterations in their lipid or electrolyte levels. Most of the perturbed parameters returned to normal levels in the recovery group.

CONCLUSION

Cisplatin nephrotoxicity in rabbits is accompanied by reductions in body weight, secondary dyslipidemia, and reduced serum potassium, calcium, and magnesium with depleted renal cortical magnesium and calcium and accumulated cortical lipids.

MATE-1 modulation by kinin B1 receptor enhances cisplatin efflux from renal cells

Cisplatin is a drug widely used in chemotherapy that frequently causes severe renal dysfunction. Organic transporters have an important role to control the absorption and excretion of cisplatin in renal cells. Deletion and blockage of kinin B1 receptor has already been show to protect against cisplatin-induced acute kidney injury. To test whether it exerts its protective function by modulating the organic transporters in kidney, we studied kinin B1 receptor knockout mice and treatment with a receptor antagonist at basal state and in presence of cisplatin. Cisplatin administration caused downregulation of renal organic transporters; in B1 receptor knockout mice, this downregulation of organic transporters in kidney was absent; and treatment by a B1 receptor antagonist attenuated the downregulation of the transporter MATE-1. Moreover, kinin B1 receptor deletion and blockage at basal state resulted in higher renal expression of MATE-1. Moreover we observed that kinin B1 receptor deletion and blockage result in less accumulation of platinum in renal tissue. Thus, we propose that B1 receptor deletion and blockage protect the kidney from cisplatin-induced acute kidney injury by upregulating the expression of MATE-1, thereby increasing the efflux of cisplatin from renal cells.

Neferine reduces cisplatin-induced nephrotoxicity by enhancing autophagy via the AMPK/mTOR signaling pathway

Cisplatin is one of the most effective chemotherapeutic agents; however, its clinical use is limited by serious side effects of which nephrotoxicity is the most important. Nephrotoxicity induced by cisplatin is closely associated with autophagy reduction and caspase activation. In this study, we investigated whether neferine, an autophagy inducer, had a protective effect against cisplatin-induced nephrotoxicity. In an in vitro cisplatin-induced nephrotoxicity model, we determined that neferine was able to induce autophagy and that pretreatment with neferine not only attenuated cisplatin-induced cell apoptosis but further activated cell autophagy. This pro-survival effect was abolished by the autophagic flux inhibitor chloroquine. Furthermore, neferine pretreatment activated the AMPK/mTOR pathway; however, pharmacological inhibition of AMPK abolished neferine-mediated autophagy and nephroprotection against cisplatin-induced apoptosis. Collectively, our findings suggest for the first time the possible protective mechanism of neferine, which is crucial for its further development as a potential therapeutic agent for cisplatin-induced nephrotoxicity.

Comparative study of allogenic and xenogeneic mesenchymal stem cells on cisplatin-induced acute kidney injury in Sprague-Dawley rats

Background

The paracrine and regenerative activities of mesenchymal stem cells (MSCs) may vary with different stem cell sources. The aim of the present study is to compare the effects of MSCs from different sources on acute kidney injury (AKI) induced by cisplatin and their influence on renal regeneration.

Methods

A single intraperitoneal injection of cisplatin (5 mg/kg) was used to induce AKI in 120 Sprague-Dawley rats. Rats were treated with either rat bone marrow stem cells (rBMSCs), human adipose tissue-derived stem cells (hADSCs), or human amniotic fluid-derived stem cells (hAFSCs). 5 × 10⁶ MSCs of different sources were administered through rat tail vein in a single dose, 24 hours after cisplatin injection. Within each group, rats were sacrificed at the 4th, 7th, 11th, and 30th day after cisplatin injection. Serum creatinine, BUN, and renal tissue oxidative stress parameters were measured. Renal tissue was scored histopathologically for evidence of injury, regeneration, and chronicity. Immunohistochemistry was also done using Ki67 for renal proliferative activity evaluation.

Results

MSCs of the three sources were able to ameliorate cisplatin-induced renal function deterioration and tissue damage. The rat BMSCs-treated group had the lowest serum creatinine by day 30 (0.52 ± 0.06) compared to hADSCs and hAFSCs. All MSC-treated groups had nearly equal antioxidant activity as indicated by the decreased renal tissue malondialdehyde (MDA) and increased reduced glutathione (GSH) level and superoxide dismutase (SOD) activity at different time intervals. Additionally, all MSCs improved injury and regenerative scores. Rat BMSCs had the highest count and earliest proliferative activity in the renal cortex by day 7 as identified by Ki67; while, hAFSCs seem to have the greatest improvement in the regenerative and proliferative activities with a higher count of renal cortex Ki67-positive cells at day 11 and with the least necrotic lesions.

Conclusions

Rat BMSCs, hADSCs, and hAFSCs, in early single IV dose, had a renoprotective effect against cisplatin-induced AKI, and were able to reduce oxidative stress markers. Rat BMSCs had the earliest proliferative activity by day 7; however, hAFSCs seemed to have the greatest improvement in the regenerative activities. Human ADSCs were the least effective in the terms of proliferative and regenerative activities.

All-trans retinoic acid potentiates cisplatin-induced kidney injury in rats: impact of retinoic acid signaling pathway

Cisplatin (cis-diammine dichloroplatinum (II), CDDP) is a widely used drug for treatment of various types of cancers. However, CDDP-induced nephrotoxicity remains the main dose-limiting side effect. Retinoids are a group of vitamin A-related compounds that exert their effects through retinoid receptors activation. In this study, we investigated the effect of CDDP treatment on retinoic acid receptor-α (RAR-α) and retinoid X receptor-α (RXR-α) expression. In addition, we investigated the possible modulatory effects of RAR agonist, all-trans retinoic acid (ATRA), on CDDP-induced nephrotoxicity. Rats were treated with saline, DMSO, CDDP, ATRA, or CDDP/ATRA. Twenty-four hours after the last ATRA injection, rats were killed; blood samples were collected; kidneys were dissected; and biochemical, immunohistochemical, and histological examinations were performed. Our results revealed that CDDP treatment significantly increased serum levels of creatinine and urea, with concomitant decrease in serum albumin. Moreover, reduced glutathione (GSH) content as well as superoxide dismutase (SOD) and catalase (CAT) activities were significantly reduced with concurrent increase in kidney malondialdehyde (MDA) content following CDDP treatment. Furthermore, CDDP markedly upregulated tubular RAR-α, RXR-α, fibrin, and inducible nitric oxide synthase (iNOS) protein expression. Although administration of ATRA to control rats did not produce marked alterations in kidney function parameters, administration of ATRA to CDDP-treated rats significantly exacerbated CDDP-induced nephrotoxicity. In addition, CDDP/ATRA co-treatment significantly increased RAR-α, RXR-α, fibrin, and iNOS protein expression compared to CDDP alone. In conclusion, we report, for the first time, the crucial role of retinoid receptors in CDDP-induced nephrotoxicity. Moreover, our findings indicate that co-administration of ATRA with CDDP, although beneficial on the therapeutic effects, their deleterious effects on the kidney may limit their clinical use.

SUMOylation occurs in acute kidney injury and plays a cytoprotective role

SUMOylation is a form of post-translational modification where small ubiquitin-like modifiers (SUMO) are covalently attached to target proteins to regulate their properties. SUMOylation has been demonstrated during cell stress and implicated in cellular stress response. However, it is largely unclear if SUMOylation contributes to the pathogenesis of kidney diseases, such as acute kidney injury (AKI). Here we have demonstrated a dynamic change of protein SUMOylation in ischemic and cisplatin nephrotoxic AKI in mice. In rat kidney proximal tubular cells (RPTC), cisplatin-induced SUMOylation was diminished by two antioxidants (N-acetylcysteine and dimethylurea), supporting a role of oxidative stress in the activation of SUMOylation. In addition, SUMOylation by SUMO-2/3, but not SUMO-1, was partially suppressed by pifithrin-alpha (a pharmacological inhibitor of p53), supporting a role of p53 in SUMOylation by SUMO-2/3. We further examined the role of SUMOylation during cisplatin treatment of RPTC by using ginkgolic acid (GA), a pharmacological inhibitor of SUMOylation. Pretreatment with GA suppressed SUMOylation and importantly, GA enhanced apoptosis during cisplatin incubation. Taken together, the results demonstrate the first evidence of SUMOylation in AKI and suggest that SUMOylation may play a cytoprotective role in kidney tubular cells.

Luteolin ameliorates cisplatin-induced nephrotoxicity in mice through inhibition of platinum accumulation, inflammation and apoptosis in the kidney

The aim of this study was to investigate the effects of flavone luteolin against cisplatin (CP)-induced kidney injury in mice. Luteolin at doses of 10mg/kg was administered intraperitoneally (ip) once daily for 3 days following single CP (10 or 20mg/kg) ip injection. Mice were sacrificed 24h after the last dose of luteolin. The CP treatment significantly increased serum creatinine and blood urea nitrogen and induced pathohistological changes in the kidneys. Renal oxidative/nitrosative stress was evidenced by decreased glutathione (GSH) levels and increased 3-nitrotyrosine (3-NT) and 4-hydroxynonenal (4-HNE) formation as well as cytochrome P450 2E1 (CYP2E1) expression. The CP administration triggered inflammatory response in mice kidneys through activation of nuclear factor-kappaB (NF-κB) and overexpression of tumor necrosis factor-alpha (TNF-α) and cyclooxygenase-2 (COX-2). Simultaneously, the increase in renal p53 and caspase-3 expression indicated apoptosis of tubular cells. The administration of luteolin significantly reduced histological and biochemical changes induced by CP, decreased platinum (Pt) levels and suppressed oxidative/nitrosative stress, inflammation and apoptosis in the kidneys. These results suggest that luteolin is an effective nephroprotective agent, with potential to reduce Pt accumulation in the kidneys and ameliorate CP-induced nephrotoxicity.