Endotoxin and cisplatin synergistically induce renal dysfunction and cytokine production in mice

Effect of human umbilical cord blood-mesenchymal stem cells on cisplatin-induced nephrotoxicity in rats

BACKGROUND

Cisplatin-containing regimen is an effective treatment for several malignancies. However, cisplatin is an important cause of nephrotoxicity. So, many trials were performed to transplant stem cells systemically or locally to control cisplatin-induced nephrotoxicity. Stem cell therapeutic effect may be dependent on the regulation of inflammation and oxidant stress.

AIM

To investigate the effect of human umbilical cord blood-mesenchymal stem cells (hUCB-MSCs) on the histological structure, the oxidant stress, and the inflammatory gene expression in an experimental model of cisplatin-induced nephrotoxicity in rats.

METHOD

The rats were divided into 6 equal groups (each of 10 rats): Group I included normal rats that received no treatment. Group II included healthy rats that received IV hUCB-MSCs. Group III included untreated cisplatin-induced nephrotoxic rats. Group IV included cisplatin-induced nephrotoxic rats that received magnesium (Mg) injections after injury. Group V was injected with hUCB-MSCs after injury. Group VI received both Mg and hUCB-MSCs after injury. In tissue homogenates, reduced glutathione (GSH), superoxide dismutase (SOD), and malondialdehyde (MDA) activities were measured. Quantitative real-time-polymerase chain reaction (qRT-PCR) was performed to assess iNOS, TLR4, and NF-kB gene expression. Hematoxylin and eosin (H&E) staining was performed to study the histological structure of the kidney. Immunohistochemical staining of iNOS and NF-κB was performed, as well.

RESULTS

Disturbed kidney functions, oxidative status, and histological structure were seen in the rats that received cisplatin. Treated groups showed improvements in kidney functions, oxidative status, and histological structure, particularly in the combined treatment group.

CONCLUSION

In the cisplatin-induced nephrotoxicity model, hUCB-MSCs could improve the functional and morphological kidney structure by modulation of oxidative and inflammatory status.

Low HDL-C can be a biomarker to predict persistent severe AKI in septic patients? A retrospective cohort study

PURPOSES

Low HDL-C is associated with an increased risk of sepsis-associated AKI and subsequent decline in eGFR. HDL-C possesses anti-inflammatory, antioxidant, and endothelial repair-promoting properties. The use of Apo A-I mimetic peptides, which are the main structural components of HDL-C, has been shown to improve renal function in animal models of sepsis. However, the diagnostic value of low HDL-C in persistent sepsis-associated AKI remains unclear.

METHODS

This is a retrospective cohort study based on MIMIC IV (V 2.2). The study population consisted of all adult septic patients admitted to the Beth Israel Deaconess Medical Center Intensive Care Unit from 2008 to 2019, with plasma HDL-C measured within 24 h of ICU admission. The primary endpoint was persistent severe sepsis-associated acute kidney injury (SA-AKI) and the secondary endpoint is kidney replacement therapy (KRT). Logistic regression was used to assess the correlation between HDL-C and persistent severe SA-AKI and KRT, and receiver operating characteristic (ROC) curve analysis was performed to evaluate predictive ability.

RESULTS

A total of 604 cases of SA-AKI patients were included in the analysis, among which 88 cases (14.5%) experienced persistent severe SA-AKI. The median (IQR) HDL-C level in the group with persistent severe SA-AKI was lower (33.0 [24.0-45.5]) compared to the non-persistent severe SA-AKI group (42.0 [31.0-53.0]). However, HDL-C showed poor discriminatory ability with an AUROC [95%CI] of 0.62 [0.56-0.69]. Clinical prediction models based on serum creatinine concentration, 24-h creatinine change, APSIIIscore, lactate levels, APTT, and heart rate performed well in predicting persistent severe SA-AKI with an AUROC [95%CI] of 0.876 [0.84-0.91]. However, adding HDL-C to this model did not improve predictive performance.

CONCLUSIONS

The plasma HDL-C measured within 24 h after admission to the ICU does not provide a good prediction for persistent severe SA-AKI, and it does not improve the clinical predictive ability compared to conventional variables.

Paricalcitol Ameliorates Acute Kidney Injury in Mice by Suppressing Oxidative Stress and Inflammation via Nrf2/HO-1 Signaling

Effective and targeted prevention and treatment methods for acute kidney injury (AKI), a common clinical complication, still needs to be explored. Paricalcitol is a biologically active chemical that binds to vitamin D receptors in the body to exert anti-oxidant and anti-inflammatory effects. However, the molecular mechanism of the effect of paricalcitol on AKI remains unclear. The current study uses a paricalcitol pretreatment with a mouse AKI model induced by cisplatin to detect changes in renal function, pathology and ultrastructure. Results showed that paricalcitol significantly improved renal function in mice and reduced inflammatory cell infiltration and mitochondrial damage in renal tissue. Furthermore, paricalcitol markedly suppressed reactive oxygen species and malondialdehyde levels in the kidneys of AKI mice and increased the levels of glutathione, superoxide dismutase, Catalase and total anti-oxidant capacity. In addition, we detected renal necrosis and inflammation-related proteins in AKI mice by immunofluorescence and Western blot, and found that their levels were markedly decreased after paricalcitol pretreatment. Moreover, paricalcitol promotes nuclear factor erythroid 2-related factor 2 (Nrf2) in the nucleus and activates the Nrf2/heme oxygenase-1 (HO-1) signaling pathway; while HO-1 is inhibited, the protective effect of paricalcitol on the kidney is attenuated. In conclusion, paricalcitol exerts a renoprotective effect by decreasing renal oxidative injury and inflammation through Nrf2/HO-1 signaling, providing a new insight into AKI prevention.

Cisplatin-Induced Kidney Toxicity: Potential Roles of Major NAD+-Dependent Enzymes and Plant-Derived Natural Products

Cisplatin is an FDA approved anti-cancer drug that is widely used for the treatment of a variety of solid tumors. However, the severe adverse effects of cisplatin, particularly kidney toxicity, restrict its clinical and medication applications. The major mechanisms of cisplatin-induced renal toxicity involve oxidative stress, inflammation, and renal fibrosis, which are covered in this short review. In particular, we review the underlying mechanisms of cisplatin kidney injury in the context of NAD⁺-dependent redox enzymes including mitochondrial complex I, NAD kinase, CD38, sirtuins, poly-ADP ribosylase polymerase, and nicotinamide nucleotide transhydrogenase (NNT) and their potential contributing roles in the amelioration of cisplatin-induced kidney injury conferred by natural products derived from plants. We also cover general procedures used to create animal models of cisplatin-induced kidney injury involving mice and rats. We highlight the fact that more studies will be needed to dissect the role of each NAD⁺-dependent redox enzyme and its involvement in modulating cisplatin-induced kidney injury, in conjunction with intensive research in NAD⁺ redox biology and the protective effects of natural products against cisplatin-induced kidney injury.

Pro-Inflammatory Signalling PRRopels Cisplatin-Induced Toxicity

Cisplatin is a platinum-based chemotherapeutic that has long since been effective against a variety of solid-cancers, substantially improving the five-year survival rates for cancer patients. Its use has also historically been limited by its adverse drug reactions, or cisplatin-induced toxicities (CITs). Of these reactions, cisplatin-induced nephrotoxicity (CIN), cisplatin-induced peripheral neuropathy (CIPN), and cisplatin-induced ototoxicity (CIO) are the three most common of several CITs recognised thus far. While the anti-cancer activity of cisplatin is well understood, the mechanisms driving its toxicities have only begun to be defined. Most of the literature pertains to damage caused by oxidative stress that occurs downstream of cisplatin treatment, but recent evidence suggests that the instigator of CIT development is inflammation. Cisplatin has been shown to induce pro-inflammatory signalling in CIN, CIPN, and CIO, all of which are associated with persisting markers of inflammation, particularly from the innate immune system. This review covered the hallmarks of inflammation common and distinct between different CITs, the role of innate immune components in development of CITs, as well as current treatments targeting pro-inflammatory signalling pathways to conserve the use of cisplatin in chemotherapy and improve long-term health outcomes of cancer patients.

The Role of Vascular-Immune Interactions in Modulating Chemotherapy Induced Neuropathic Pain

Chemotherapy causes sensory disturbances in cancer patients that results in neuropathies and pain. As cancer survivorships has dramatically increased over the past 10 years, pain management of these patients is becoming clinically more important. Current analgesic strategies are mainly ineffective and long-term use is associated with severe side effects. The issue being that common analgesic strategies are based on ubiquitous pain mediator pathways, so when applied to clinically diverse neuropathic pain and neurological conditions, are unsuccessful. This is principally due to the lack of understanding of the driving forces that lead to chemotherapy induced neuropathies. It is well documented that chemotherapy causes sensory neurodegeneration through axonal atrophy and intraepidermal fibre degeneration causing alterations in pain perception. Despite the neuropathological alterations associated with chemotherapy-induced neuropathic pain being extensively researched, underlying causes remain elusive. Resent evidence from patient and rodent studies have indicated a prominent inflammatory cell component in the peripheral sensory nervous system in effected areas post chemotherapeutic treatment. This is accompanied by modulation of auxiliary cells of the dorsal root ganglia sensory neurons such as activation of satellite glia and capillary dysfunction. The presence of a neuroinflammatory component was supported by transcriptomic analysis of dorsal root ganglia taken from mice treated with common chemotherapy agents. With key inflammatory mediators identified, having potent immunoregulatory effects that directly influences nociception. We aim to evaluate the current understanding of these immune-neuronal interactions across different cancer therapy drug classes. In the belief this may lead to better pain management approaches for cancer survivors.

Mitigation of cisplatin induced nephrotoxicity by casticin in male albino rats

Cisplatin (CP) is a commonly used, powerful antineoplastic drug, having numerous side effects. Casticin (CAS) is considered as a free radical scavenger and a potent antioxidant. The present research was planned to assess the curative potential of CAS on CP persuaded renal injury in male albino rats. Twenty four male albino rats were distributed into four equal groups. Group-1 was considered as a control group. Animals of Group-2 were injected with 5mg/kg of CP intraperitoneally. Group-3 was co-treated with CAS (50mg/kg) orally and injection of CP (5mg/kg). Group-4 was treated with CAS (50mg/kg) orally throughout the experiment. CP administration substantially reduced the activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), glutathione S-transferase (GST), glutathione reductase (GSR), glutathione (GSH) content while increased thiobarbituric acid reactive substances (TBARS), and hydrogen peroxide (H2O2) levels. Urea, urinary creatinine, urobilinogen, urinary proteins, kidney injury molecule-1 (KIM-1), and neutrophil gelatinase-associated lipocalin (NGAL) levels were substantially increased. In contrast, albumin and creatinine clearance was significantly reduced in CP treated group. The results demonstrated that CP significantly increased the inflammation indicators including nuclear factor kappa-B (NF-κB), tumor necrosis factor-α (TNF-α), Interleukin-1β (IL-1β), Interleukin-6 (IL-6) levels and cyclooxygenase-2 (COX-2) activity and histopathological damages. However, the administration of CAS displayed a palliative effect against CP-generated renal toxicity and recovered all parameters by bringing them to a normal level. These results revealed that the CAS is an effective compound having the curative potential to counter the CP-induced renal damage.

The Mechanism of Drug Nephrotoxicity and the Methods for Preventing Kidney Damage

Acute kidney injury (AKI) is a global health challenge of vast proportions, as approx. 13.3% of people worldwide are affected annually. The pathophysiology of AKI is very complex, but its main causes are sepsis, ischemia, and nephrotoxicity. Nephrotoxicity is mainly associated with the use of drugs. Drug-induced AKI accounts for 19-26% of all hospitalized cases. Drug-induced nephrotoxicity develops according to one of the three mechanisms: (1) proximal tubular injury and acute tubular necrosis (ATN) (a dose-dependent mechanism), where the cause is related to apical contact with drugs or their metabolites, the transport of drugs and their metabolites from the apical surface, and the secretion of drugs from the basolateral surface into the tubular lumen; (2) tubular obstruction by crystals or casts containing drugs and their metabolites (a dose-dependent mechanism); (3) interstitial nephritis induced by drugs and their metabolites (a dose-independent mechanism). In this article, the mechanisms of the individual types of injury will be described. Specific groups of drugs will be linked to specific injuries. Additionally, the risk factors for the development of AKI and the methods for preventing and/or treating the condition will be discussed.

MiR-3168, miR-6125, and miR-4718 as potential predictors of cisplatin-induced nephrotoxicity in patients with head and neck cancer

Background

No biomarker is available for identifying cancer patients at risk of developing nephrotoxicity when treated with cisplatin.

Methods

We performed microRNA (miRNA) sequencing using plasma collected 5 days after cisplatin treatment (D5) from twelve patients with head and neck cancer with and without nephrotoxicity (grade ≥ 2 increased serum creatinine). The most differentially expressed miRNAs between the two groups were selected for quantification at baseline and D5 in a larger cohort of patients. The association between miRNAs and nephrotoxicity was evaluated by calculating the odds ratio (OR) from univariate logistic regression. Receiver operating characteristic curves (ROC) were used to estimate the area under the curve (AUC), sensitivity, and specificity.

Results

MiR-3168 (p = 1.98 × 10^− 8), miR-4718 (p = 4.24 × 10^− 5), and miR-6125 (p = 6.60 × 10^− 5) were the most differentially expressed miRNAs and were further quantified in 43, 48, and 53 patients, respectively. The baseline expression of miR-3168 (p = 0.0456, OR = 1.03, 95% CI: 1.00–1.06) and miR-4718 (p = 0.0388, OR = 1.56, 95% CI: 1.03–2.46) were associated with an increased risk of nephrotoxicity, whereas miR-6125 showed a trend (p = 0.0618, OR = 1.73, 95% CI: 0.98–3.29). MiR-4718 showed the highest AUC (0.77, 95% CI: 0.61–0.93) with sensitivity of 66.76 and specificity of 79.49.

Conclusions

We have provided evidence of baseline plasmatic expression of miR-3168, miR-6125, and miR-4718 as potential predictors of cisplatin-induced nephrotoxicity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08317-2.

Toll-like receptor 4 is activated by platinum and contributes to cisplatin-induced ototoxicity

Toll-like receptor 4 (TLR4) recognizes bacterial lipopolysaccharide (LPS) and can also be activated by some Group 9/10 transition metals, which is believed to mediate immune hypersensitivity reactions. In this work, we test whether TLR4 can be activated by the Group 10 metal platinum and the platinum-based chemotherapeutic cisplatin. Cisplatin is invaluable in childhood cancer treatment but its use is limited due to a permanent hearing loss (cisplatin-induced ototoxicity, CIO) adverse effect. We demonstrate that platinum and cisplatin activate pathways downstream of TLR4 to a similar extent as the known TLR4 agonists LPS and nickel. We further show that TLR4 is required for cisplatin-induced inflammatory, oxidative, and cell death responses in hair cells in vitro and for hair cell damage in vivo. Finally, we identify a TLR4 small molecule inhibitor able to curtail cisplatin toxicity in vitro. Thus, our findings indicate that TLR4 is a promising therapeutic target to mitigate CIO.

High-Density Lipoproteins and Acute Kidney Injury

High-density lipoprotein (HDL) particles, best known for their anti-atherosclerotic effects, also may play a beneficial role during acute renal stress. HDL from healthy human beings also shows anti-inflammatory and anti-oxidant capacities, promotes endothelial function and repair, and serves as a systemic signaling mechanism facilitating rapid interorgan communication during times of physiologic stress. Higher concentrations of HDL are associated with less acute kidney injury after sepsis, cardiac and vascular surgery, and contrast-exposure during percutaneous coronary interventions. A better understanding of the interplay between HDL and the kidney both under homeostatic conditions and under acute physiologic stress could lead to the identification of novel risk factors and therapeutic targets for acute kidney injury prevention and treatment in the future.

Mechanisms of Cisplatin-Induced Acute Kidney Injury: Pathological Mechanisms, Pharmacological Interventions, and Genetic Mitigations

Administration of the chemotherapeutic agent cisplatin leads to acute kidney injury (AKI). Cisplatin-induced AKI (CIAKI) has a complex pathophysiological map, which has been linked to cellular uptake and efflux, apoptosis, vascular injury, oxidative and endoplasmic reticulum stress, and inflammation. Despite research efforts, pharmaceutical interventions, and clinical trials spanning over several decades, a consistent and stable pharmacological treatment option to reduce AKI in patients receiving cisplatin remains unavailable. This has been predominately linked to the incomplete understanding of CIAKI pathophysiology and molecular mechanisms involved. Herein, we detail the extensively known pathophysiology of cisplatin-induced nephrotoxicity that manifests and the variety of pharmacological and genetic alteration studies that target them.

Toll-like receptor 4: An attractive therapeutic target for acute kidney injury

Acute kidney injury (AKI) is a progressive renal complication which significantly affects the patient's life with huge economic burden. Untreated acute kidney injury eventually progresses to a chronic form and end-stage renal disease. Although significant breakthroughs have been made in recent years, there are still no effective pharmacological therapies for the treatment of acute kidney injury. Toll-like receptor 4 (TLR4) is a well-characterized pattern recognition receptor, and increasing evidence has shown that TLR4 mediated inflammatory response plays a pivotal role in the pathogenesis of acute kidney injury. The expression of TLR4 has been seen in resident renal cells, including podocytes, mesangial cells, tubular epithelial cells and endothelial cells. Activation of TLR4 signaling regulates the transcription of numerous pro-inflammatory cytokines and chemokines, resulting in renal inflammation. Therefore, targeting TLR4 and its downstream effectors could serve as an effective therapeutic intervention to prevent renal inflammation and subsequent kidney damage. For the first time, this review summarizes the literature on acute kidney injury from the perspective of TLR4 from year 2010 to 2020. In the current review, the role of TLR4 signaling pathway in AKI with preclinical evidence is discussed. Furthermore, we have highlighted several compounds of natural and synthetic origin, which have the potential to avert the renal TLR4 signaling in preclinical AKI models and have shown protection against AKI. This scientific review provides new ideas for targeting TLR4 in the treatment of AKI and provides strategies for the drug development against AKI.

Loganin Attenuates the Severity of Acute Kidney Injury Induced by Cisplatin through the Inhibition of ERK Activation in Mice

Cisplatin is the most widely used chemotherapeutic agent. However, it often causes nephrotoxicity, which results in acute kidney injury (AKI). Therefore, we urgently need a drug that can reduce the nephrotoxicity induced by cisplatin. Loganin is a major iridoid glycoside isolated from Corni fructus that has been used as an anti-inflammatory agent in various pathological models. However, the renal protective activity of loganin remains unclear. In this study, to examine the protective effect of loganin on cisplatin-induced AKI, male C57BL/6 mice were orally administered with loganin (1, 10, and 20 mg/kg) 1 h before intraperitoneal injection of cisplatin (10 mg/kg) and sacrificed at three days after the injection. The administration of loganin inhibited the elevation of blood urea nitrogen (BUN) and creatinine (CREA) in serum, which are used as biomarkers of AKI. Moreover, histological kidney injury, proximal tubule damages, and renal cell death, such as apoptosis and ferroptosis, were reduced by loganin treatment. Also, pro-inflammatory cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α, reduced by loganin treatment. Furthermore, loganin deactivated the extracellular signal-regulated kinases (ERK) 1 and 2 during AKI. Taken together, our results suggest that loganin may attenuate cisplatin-induced AKI through the inhibition of ERK1/2.

MUC1 Mitigates Renal Injury and Inflammation in Endotoxin Induced Acute Kidney Injury by Inhibiting the TLR4-MD2 Axis and Reducing Pro-Inflammatory Macrophages Infiltration

ABSTRACT

Sepsis is the leading cause of acute kidney injury (AKI) in critical care patients. A cornerstone of sepsis-associated AKI is dysregulated inflammation driven by excessive activation of Toll-like receptor 4 (TLR4) pathway. MUC1, a membrane bound mucin expressed in both epithelial tubular cells and renal macrophages, has been shown to be involved in the regulation of TLRs. Therefore we hypothesized that MUC1 could mitigate the renal inflammatory response to TLR4 activation. To test this hypothesis, we used a murine model of endotoxin-induced AKI by intraperitoneal injection of lipopolysaccharide (LPS). We showed that Muc1-/- mice have a more severe renal dysfunction, an increased activation of the tissular NF-kB pathway and secreted more pro inflammatory cytokines compare to Muc1+/+ mice. By flow cytometry, we observed that the proportion of M1 (pro-inflammatory) macrophages in the kidneys of Muc1-/- mice was significantly increased. In human and murine primary macrophages, we showed that MUC1 is only induced in M1 type macrophages and that macrophages derived from Muc1-/- mice secreted more pro-inflammatory cytokines. Eventually, in HEK293 cells, we showed that (i) MUC1 cytosolic domain (CT) seems necessary for the negative regulation of TLR4 (ii) by proximity ligation assay, MUC1-CT is in close relationship with TLR4 and acts as a competitive inhibitor of the recruitment of MYD88. Overall our results support that in the context of endotoxin-induced AKI, MUC1 plays a significant role in controlling disease severity by regulating negatively the TLR4-MD2 axis.

Phloretin and phloridzin guard against cisplatin-induced nephrotoxicity in mice through inhibiting oxidative stress and inflammation

AIM

Cisplatin (Cis) is widely used chemotherapeutic and has some serious side effects as nephrotoxicity. Phloretin (PH) and Phloridzin (PZ) are known their anti-oxidant anti-inflammatory effects. We aimed to examine the protective effects of PH and PZ on cisplatin-induced nephrotoxicity.

MAIN METHODS

Totally, 48 Balb/C female mice were separated into eight groups (n = 6). First day, single dose of cisplatin (20 mg/kg intraperitoneal) was administered to induce toxicity. PH and PZ were given (50 and 100 mg/kg orally) to treatment groups during 3 days. After the experimental procedures serum renal function enzymes (BUN and Creatinine), oxidative parameters (SOD, GSH and MDA), nuclear agent NFKβ, inflammatory cytokines (Tnf-α and IL1β) and HSP70 expressions and histopathological assessments were analyzed.

KEY FINDINGS

Serum enzymes, tissue cytokines and oxidative stress were increased after the Cis treatment. PH and PZ treatments normalized all parameters compared to Cis administrated group. After the treatments, SOD activities and GSH levels were increased while MDA levels were decreased. PH and PZ treatments decreased Tnf-α, IL1β and NFKβ mRNA expressions. Cis significantly increased the HSP70 expression while PH and PZ administrations significantly decreased. Similar the biochemical and molecular results, PH and PZ showed positive effects on tissue pathological parameters. Cisplatin cause a lot of abnormal structures as tubular and glomeruli damages on the kidney.

SIGNIFICANCE

PH and PZ play important physiological roles in the prevention of nephrotoxicity. Antioxidant and anti-inflammatory effects of PH and PZ demonstrated visible protective effects in the cisplatin-induced nephrotoxicity model.

IL-10 from dendritic cells but not from T regulatory cells protects against cisplatin-induced nephrotoxicity

Interleukin-10 (IL-10), a cytokine with anti-inflammatory effects, is produced by renal parenchymal cells and bone marrow derived cells. Both endogenous and exogenous IL-10 are protective in cisplatin-induced acute kidney injury. However, the source of endogenous IL-10 in cisplatin-induced nephrotoxicity is not clear. Bone marrow chimera experiments in IL10-KO mice indicated that bone marrow derived cells were the primary source of IL-10 in cisplatin nephrotoxicity. Cell specific deletion of IL-10 in T regulatory cells and dendritic cells was accomplished using Foxp3 and CD11c driven cre recombination in IL10^flox/flox mice, respectively. Upon treatment with cisplatin, both the IL10^flox/flox and the Foxp3^YFP-Cre x IL10^flox/flox mice developed similar degrees of kidney injury. However, mice with the dendritic cell deletion of IL-10 showed more severe structural and functional changes in the kidney compared to the IL10^flox/flox mice. These results indicate that IL-10 from dendritic cells but not from T regulatory cells offers significant endogenous protection against cisplatin induced nephrotoxicity.

Impact of garlic (Allium sativum) oil on cisplatin-induced hepatorenal biochemical and histopathological alterations in rats

Cisplatin (cis-diamminedichloridoplatinum II [CDDP]) is a chemotherapeutic agent used for treating different cancers types. However, its usage is limited because it induces harmful toxicities in multiple organs, including nephrotoxicity and hepatotoxicity. Garlic oil (GO) has several pharmacological activities, including antioxidant activity. The aim of the study is to evaluate the protective and antioxidant effects of GO against CDDP-induced acute liver and kidney injuries in male rats. CDDP-treated rats showed increased serum ALT, AST, ALP, LDH, uric acid, urea, creatinine, and IL-6 levels. Moreover, CDDP-treated rats showed significantly increased MDA and NO levels and decreased GSH level and T.SOD and CAT activities in hepatic and renal tissues compared with control rats. GO administration, especially at a dose of 100 ml/kg, alleviated CDDP-induced adverse biochemical and histopathological alterations and restored them to their normal values. These results suggest that GO reverses CDDP-induced hepatorenal damage by exerting antioxidant and anti-inflammatory effects.

New Insights in the Pathogenesis of Cisplatin-Induced Nephrotoxicity

Cisplatin (cis-diamminedichloroplatinum II) is a widely used chemotherapeutic agent. However, efficacy and clinical utility of this drug is significantly limited by severe side effects such as nephrotoxicity which develops due to renal accumulation and bio-transformation in proximal tubular epithelial cells. Cisplatin-induced nephrotoxicity can be manifested as acute kidney injury (AKI), or as different types of tubulopathies, salt wasting, loss of urinary concentrating ability, and magnesium wasting. The attenuation of cisplatin-caused AKI is currently accomplished by hydration, magnesium supplementation or mannitol-induced forced diuresis. However, mannitol treatment causes over-diuresis and consequent dehydration, indicating an urgent need for the clinical use of newly designed, safe and efficacious renoprotective drug, as an additive therapy for high dose cisplatin-treated patients. Accordingly, we emphasized current knowledge regarding molecular mechanisms responsible for cisplatin-caused nephrotoxicity and we described in detail the main clinical manifestations of cisplatin-induced renal dysfunction in order to pave the way for the design of new therapeutic approaches that can minimize detrimental effects of cisplatin in the kidneys. Having in mind that most of cisplatin-induced cytotoxic effects against renal cells are, at the same time, involved in anti-tumor activity of cisplatin, new nephroprotective therapeutic strategies have to prevent renal injury and inflammation without affecting cisplatin-induced toxicity against malignant cells.

A glance at molecular mechanisms underlying cisplatin-induced nephrotoxicity and possible renoprotective strategies: a narrative review

Cisplatin is a platinum-based drug that is usually used for the treatment of many carcinomas. However, it comes with several devastating side effects, including nephrotoxicity. Cisplatin toxicity is a very complex process, which is exacerbated by the accumulation of cisplatin in renal tubular cells via passive diffusion and transporter-mediated processes. Once cisplatin enters these cells, it induces the formation of reactive oxygen species that cause cellular damage, including DNA damage, inflammation, and eventually cell death. On a small scale, these damages can be mitigated by cellular antioxidant defense mechanism. However, on a large scale, such as in chemotherapy, this defense mechanism may fail, resulting in nephrotoxicity. The current article reviews the molecular mechanisms underlying cisplatin-induced nephrotoxicity and possible renoprotective strategies to determine novel therapeutic interventions for alleviating this toxicity.

Pharmacological Activation of Sirt1 Ameliorates Cisplatin-Induced Acute Kidney Injury by Suppressing Apoptosis, Oxidative Stress, and Inflammation in Mice

Sirtuin 1 (Sirt1) is an essential modulator of cellular metabolism and has pleiotropic effects. It was recently reported that Sirt1 overexpression in kidney tubule ameliorates cisplatin-induced acute kidney injury (AKI). However, whether pharmacological activation of Sirt1 also has a beneficial effect against the disease remains unclear. In this study, we aimed to evaluate whether SRT1720, a potent and specific activator of Sirt1, could ameliorate cisplatin-induced AKI. We found that SRT1720 treatment ameliorated cisplatin-induced acute renal failure and histopathological alterations. Increased levels of tubular injury markers in kidneys were significantly attenuated by SRT1720. SRT1720 treatment also suppressed caspase-3 activation and apoptotic cell death. Increased expression of 4-hydroxynonenal, elevated malondialdehyde level, and decreased ratio of reduced glutathione/oxidized glutathione after cisplatin injection were significantly reversed by SRT1720. In addition, SRT1720 treatment decreased renal expression of pro-inflammatory cytokines and prevented macrophage infiltration into damaged kidneys. We also showed that the therapeutic effects of SRT1720 were associated with reduced acetylation of p53 and nuclear factor kappa-B p65 and preservation of peroxisome function, as evidenced by recovered expression of markers for number and function of peroxisome. These results suggest that Sirt1 activation by SRT1720 would be a useful therapeutic option for cisplatin-induced AKI.

Design, synthesis and evaluation of PD176252 analogues for ameliorating cisplatin-induced nephrotoxicity

Cisplatin is a clinical chemotherapy drug for cancers; however, its remarkably high kidney toxicity and other toxicities pose a danger to patients. As the small molecule inhibitor of GRPR, PD176252 can inhibit the growth and proliferation of various cancer cells, but the characteristics of high toxicity and poor water solubility has limited its use as a drug. When we studied PD176252 for the reduction of toxicity of cisplatin, we modified its structure to synthesize 16 analogues. Surprisingly, the analogues showed reduced cisplatin-induced renal toxicity, and unlike PD176252, the analogues 5d and 5m were almost non-toxic to the normal HK2 cells. Furthermore, the analogue 5d and PD176252 were subjected to cisplatin-induced inflammatory response in vitro. The results showed that 5d was able to better prevent this condition by effectively inhibiting its inflammatory response. Thus, this study will help in clinically reducing the side effects of cisplatin.

Molecular mechanisms of cisplatin-induced nephrotoxicity: a balance on the knife edge between renoprotection and tumor toxicity

Background

Cisplatin (cis-diamminedichloroplatinum II, CDDP) is one of the most effective chemotherapeutic agents. However, its clinical use is limited due to the severe side effects, including nephrotoxicity and acute kidney injury (AKI) which develop due to renal accumulation and biotransformation of CDDP. The alleviation or prevention of CDDP-caused nephrotoxicity is currently accomplished by hydration, magnesium supplementation or mannitol-induced forced diuresis which is considered for high-dose CDDP-treated patients. However, mannitol treatment causes over-diuresis and consequent dehydration in CDDP-treated patients, indicating an urgent need for the clinical use of safe and efficacious renoprotective drug as an additive therapy for high dose CDDP-treated patients.

Main body

In this review article we describe in detail signaling pathways involved in CDDP-induced apoptosis of renal tubular cells, oxidative stress and inflammatory response in injured kidneys in order to pave the way for the design of new therapeutic approaches that can minimize CDDP-induced nephrotoxicity. Most of these molecular pathways are, at the same time, crucially involved in cytotoxic activity of CDDP against tumor cells and potential alterations in their function might mitigate CDDP-induced anti-tumor effects.

Conclusion

Despite the fact that many molecules were designated as potential therapeutic targets for renoprotection against CDDP, modulation of CDDP-induced nephrotoxicity still represents a balance on the knife edge between renoprotection and tumor toxicity.

Increased TLR4 Expression Aggravates Sepsis by Promoting IFN-γ Expression in CD38-/- Mice

Gram-negative bacterial sepsis accounts for up to 50% worldwide sepsis that causes hospital mortality. Acute kidney injury (AKI), a common complication of Gram-negative bacterial sepsis, is caused by Toll-like receptor 4 (TLR4) activation. Lipopolysaccharide (LPS) is an endotoxin in Gram-negative bacteria and is recognized specifically by TLR4, which initiates innate immune response. Also, TLR4 signaling pathway activation is essential in response to LPS infection. CD38 is one of the well-known regulators of innate immunity, whose dysregulation contributes to sepsis. Many studies have proven that an attenuated Gram-positive bacterium induces sepsis in a CD38-blocking model. However, the pathogenesis of Gram-negative bacteria-induced sepsis in a CD38^−/− mouse model remains unclear. The aim of this study is to investigate whether kidney injury is still attenuated in a LPS-induced CD38^−/− sepsis model and identify the potential mechanism. We assess the severity of kidney injury related to proinflammatory cytokine expressions (IFN-γ, TNF-α, IL-1β, and IL-6) in WT and CD38^−/− mice. Our results showed more aggravated kidney damage in CD38^−/− mice than in WT mice, accompanied with an increase of proinflammatory cytokine expression. In addition, compared with CD38^−/−TLR4^mut mice, we found an increase of TLR4 expression and mRNA expression of these cytokines in the kidney of CD38^−/− mice, although only increased IFN-γ level was detected in the serum. Taken together, these results demonstrated that an increased TLR4 expression in CD38^−/− mice could contribute to the aggravation of AKI through boosting of the production of IFN-γ.

Tenascin-C protects against acute kidney injury by recruiting Wnt ligands

The development of acute kidney injury (AKI) is a complex process involving tubular, inflammatory, and vascular components, but less is known about the role of the interstitial microenvironment. We have previously shown that the extracellular matrix glycoprotein tenascin-C (TNC) is induced in fibrotic kidneys. In mouse models of AKI induced by ischemia-reperfusion injury (IRI) or cisplatin, TNC was induced de novo in the injured sites and localized to the renal interstitium. The circulating level of TNC protein was also elevated in AKI patients after cardiac surgery. Knockdown of TNC by shRNA in vivo aggravated AKI after ischemic or toxic injury. This effect was associated with reduced renal β-catenin expression, suggesting an impact on Wnt signaling. In vitro, TNC protected tubular epithelial cells against apoptosis and augmented Wnt1-mediated β-catenin activation. Co-immunoprecipitation revealed that TNC physically interacts with Wnt ligands. Furthermore, a TNC-enriched kidney tissue scaffold prepared from IRI mice was able to recruit and concentrate Wnt ligands from the surrounding milieu ex vivo. The ability to recruit Wnt ligands in this ex vivo model diminished after TNC depletion. These studies indicate that TNC is specifically induced at sites of injury and recruits Wnt ligands, thereby creating a favorable microenvironment for tubular repair and regeneration after AKI.

Cisplatin-Induced Rodent Model of Kidney Injury: Characteristics and Challenges

Cisplatin is an antitumor drug used in the treatment of a wide variety of malignancies. However, its primary dose-limiting side effect is kidney injury, which is a major clinical concern. To help understand mechanisms involved in the development of kidney injury, cisplatin rodent model has been developed. Given the complex pathogenesis of kidney injury, which involves both local events in the kidney and interconnected and interdependent systemic effects in the body, cisplatin rodent model is indispensable in the investigation of underlying mechanisms and potential treatment strategies of both acute and chronic kidney injury. Cisplatin rodent model is well appreciated and widely used model due to its simplicity. It has many similarities to human cisplatin nephrotoxicity, which are mentioned in the paper. In spite of its simplicity and wide applicability, there are also traps that need to be taken into account when using cisplatin model. The present paper is aimed at giving a concise insight into the complex characteristics of cisplatin rodent model and heterogeneity of cisplatin dosage regimens as well as outlining factors that can severely influence the outcome of the model and the study. Challenges for future research are also mentioned.

Evidence of latent molecular diversity determining the virulence of community-associated MRSA USA300 clones in mice

Introduction

The USA300 clone of community‐associated MRSA is reported to be hypervirulent and epidemic in the United States. This clone causes a variety of diseases from lethal pneumonia to mild skin infections. We hypothesized that evolutionary diversity may exist among USA300 clones, which may link virulence traits with host responses and mortality rates.

Methods

USA300 isolates from severe pneumonia (IP) and skin infection (IS) were characterized by pulsed‐field gel electrophoresis (PFGE) and next‐generation sequencing. Their virulence traits and host responses were compared in a lung infection model.

Results

The two USA300 isolates were found to be identical in genomic analysis. Robust IL‐6 production, aggregation of bacteria, and hemorrhaging were observed in IP‐infected lungs, which were associated with a higher rate of mortality than that observed with strain IS. Few neutrophils were detected in the lungs infected with strain IP, even at high bacterial loads. Massive production of α‐toxin and coagulase were evident during the early phase of IP infection, and robust gene expression of hla (α‐toxin) and lukS‐PV (Panton–Valentine leukocidin), but not coa, agrA, or rnaIII, was confirmed in vitro. Strain IP also induced strong hemolysis in red blood cells.

Conclusions

The present data demonstrated latent diversity in the virulence of USA300 clones. Unknown regulatory mechanisms, probably involving a host factor(s) as a trigger, may govern the virulence expression and resultant high mortality in certain sub‐clones of USA300.

Role of interleukin-17 in a murine community-associated methicillin-resistant Staphylococcus aureus pneumonia model

Interleukin (IL)-17 is a key member of the Th17 cytokines and has been reported to be involved in the pathomechanisms underlying various diseases, including infectious diseases. Infections with community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) have garnered worldwide attention, and the representative USA300 strain is known to cause pneumonia in healthy people, which can be lethal. However, little is known about the role of IL-17 in CA-MRSA pneumonia. In this study, we investigated the role of IL-17 in a CA-MRSA pneumonia animal model. Mortality was higher and occurred at an earlier stage of infection in the IL-17A-knockout mice than in the wild-type (P < 0.01) and IL-17A/F-knockout mice (P < 0.05); however, no significant difference in the intrapulmonary bacterial counts was observed among the three groups of mice. Moreover, the IL-17A-knockout group showed significantly higher levels of IL-17F and granulocyte-colony stimulating factor (G-CSF) and a significantly higher neutrophil count in the bronchoalveolar lavage fluid than the other groups. These results confirmed that G-CSF expression significantly increased, and significant neutrophilic inflammation occurred under conditions of IL-17A deficiency in the murine CA-MRSA pneumonia model.

TAK1 mediates apoptosis via p38 involve in ischemia-induced renal fibrosis

Renal fibrosis is a common and characteristic symptom of chronic kidney disease (CKD). However, the molecular mechanisms of renal fibrosis remain elusive. Ischemia injury, as a major cause of AKI, deserves more attention in order to improve the knowledge of AKI-induced fibrosis. Transforming growth factor-β (TGF-β)-activated kinase 1 (TAK1) interacts directly with TGF-β, which play a critical role in the progression of fibrosis. Therefore, the present study aimed to investigate the role of TAK1 in the pathogenesis of ischemia-induced renal fibrosis. Compared with mice in the vehicle group, mice intraperitoneally injected with TAK1 inhibitor were found to have lower serum creatinine, less tubular damage and more mild fibrosis following ischemia-induced AKI. Furthermore, inhibition of TAK1 reduced p38 phosphorylation, decreased expression of Bax and caspase 3 and apoptosis cells in kidneys of mice treated with IR-induced AKI. Compared with vehicle-treated renal tubular epithelial cells, TAK1 overexpression cells were found to have a higher apoptosis and fibrosis index level and p38 phosphorylation following hypoxia/reoxygenation (H/R) treatment. Furthermore, the p38 inhibitor combined with TAK1 overexpression verified the role of TAK1/p38 signaling pathway in apoptosis and fibrosis index level of renal tubular epithelial cells treated with H/R. Thus, our results show that TAK1 plays an important role in the pathogenesis of ischemia-induced renal fibrosis and may mediate p38-regulated cell apoptosis.

Fibroblast-Specific β-Catenin Signaling Dictates the Outcome of AKI

AKI is a devastating condition with high morbidity and mortality. The pathologic features of AKI are characterized by tubular injury, inflammation, and vascular impairment. Whether fibroblasts in the renal interstitium have a role in the pathogenesis of AKI is unknown. In this study, we investigated the role of fibroblast-specific β-catenin signaling in dictating the outcome of AKI, using conditional knockout mice in which β-catenin was specifically ablated in fibroblasts (Gli1-β-cat-/-). After ischemia-reperfusion injury (IRI), Gli1-β-cat-/- mice had lower serum creatinine levels and less morphologic injury than Gli1-β-cat+/+ littermate controls. Moreover, we detected fewer apoptotic cells, as well as decreased cytochrome C release; reduced expression of Bax, FasL, and p53; and increased phosphorylation of Akt, in the Gli1-β-cat-/- kidneys. Gli1-β-cat-/- kidneys also exhibited upregulated expression of proliferating cell nuclear antigen and Ki-67, which are markers of cell proliferation. Furthermore, Gli1-β-cat-/- kidneys displayed suppressed NF-κB signaling and cytokine expression and reduced infiltration of inflammatory cells. Notably, loss of β-catenin in fibroblasts induced renal expression of hepatocyte growth factor (HGF) and augmented the tyrosine phosphorylation of c-met receptor after IRI. In vitro, treatment with Wnt ligands or ectopic expression of active β-catenin inhibited HGF mRNA and protein expression and repressed HGF promoter activity. Collectively, these results suggest that fibroblast-specific β-catenin signaling can control tubular injury and repair in AKI by modulating HGF expression. Our studies uncover a previously unrecognized role for interstitial fibroblasts in the pathogenesis of AKI.

CXCL16 regulates cisplatin-induced acute kidney injury

The pathogenesis of cisplatin-induced acute kidney injury (AKI) is characterized by tubular cell apoptosis and inflammation. However, the molecular mechanisms are not fully understood. We found that CXCL16 was induced in renal tubular epithelial cells in response to cisplatin-induced AKI. Therefore, we investigated whether CXCL16 played a role in cisplatin–induced tubular cell apoptosis and inflammation. Wild-type and CXCL16 knockout mice were administrated with vehicle or cisplatin at 20 mg/kg by intraperitoneal injection. CXCL16 knockout mice had lower blood urea nitrogen and less tubular damage following cisplatin-induced AKI as compared with wild-type mice. Genetic disruption of CXCL16 reduced tubular epithelial cell apoptosis and decreased caspase-3 activation. Furthermore, CXCL16 deficiency inhibited infiltration of macrophages and T cells into the kidneys following cisplatin treatment, which was associated with reduced expression of the proinflammatory cytokines in the kidneys. Taken together, our results indicate that CXCL16 plays a crucial role in the pathogenesis of cisplatin–induced AKI through regulation of apoptosis and inflammation and maybe a novel therapeutic target for cisplatin-induced AKI.

Molecular Mechanisms of Curcumin Renoprotection in Experimental Acute Renal Injury

As a highly perfused organ, the kidney is especially sensitive to ischemia and reperfusion. Ischemia-reperfusion (IR)-induced acute kidney injury (AKI) has a high incidence during the perioperative period in the clinic and is an important link in ischemic acute renal failure (IARF). Therefore, IR-induced AKI has important clinical significance and it is necessary to explore to develop drugs to prevent and alleviate IR-induced AKI. Curcumin [diferuloylmethane, 1,7-bis(4-hydroxy-3-methoxiphenyl)-1,6-heptadiene-3,5-dione)] is a polyphenol compound derived from Curcuma longa (turmeric) and was shown to have a renoprotective effect on ischemia-reperfusion injury (IRI) in a previous study. However, the specific mechanisms underlying the protective role of curcumin in IR-induced AKI are not completely understood. APPL1 is a protein coding gene that has been shown to be involved in the crosstalk between the adiponectin-signaling and insulin-signaling pathways. In the study, to investigate the molecular mechanisms of curcumin effects in kidney ischemia/reperfusion model, we observed the effect of curcumin in experimental models of IR-induced AKI and we found that curcumin treatment significantly increased the expression of APPL1 and inhibited the activation of Akt after IR treatment in the kidney. Our in vitro results showed that apoptosis of renal tubular epithelial cells was exacerbated with hypoxia-reoxygenation (HR) treatment compared to sham control cells. Curcumin significantly decreased the rate of apoptosis in renal tubular epithelial cells with HR treatment. Moreover, knockdown of APPL1 activated Akt and subsequently aggravated apoptosis in HR-treated renal tubular epithelial cells. Conversely, inhibition of Akt directly reversed the effects of APPL1 knockdown. In summary, our study demonstrated that curcumin mediated upregulation of APPL1 protects against ischemia reperfusion induced AKI by inhibiting Akt phosphorylation.

Protective Effects of Gemigliptin, a Dipeptidyl Peptidase-4 Inhibitor, against Cisplatin-Induced Nephrotoxicity in Mice

Dipeptidyl peptidase-4 (DPP-4) inhibitors are widely used antihyperglycemic agents for the treatment of type 2 diabetes mellitus. Recently, the pleiotropic actions of DPP-4 inhibitors have drawn much attention. In the present study, we aimed to examine whether gemigliptin, a recently developed DPP-4 inhibitor, could protect against cisplatin-induced nephrotoxicity. We showed that pretreatment with gemigliptin attenuated cisplatin-induced renal dysfunction, as shown by analysis of plasma creatinine levels and blood urea nitrogen and histological damage. Elevated plasma levels of active glucagon-like peptide-1 were observed in gemigliptin-pretreated mice after cisplatin treatment, compared to that in cisplatin alone-treated mice. Gemigliptin attenuated cisplatin-induced apoptotic cell death, as assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling and Western blot analysis in the kidneys. Gemigliptin also decreased the plasma levels of tumor necrosis factor-α and monocyte chemoattractant protein-1 and attenuated nuclear staining of nuclear factor kappa-B p65 in the kidneys. In addition, gemigliptin increased the protein expression of heme oxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductase 1 (NQO1) in the kidneys of cisplatin-treated mice. Taken together, these results suggest that pretreatment with gemigliptin protects against cisplatin-induced nephrotoxicity in mice, possibly via inhibition of apoptotic cell death and inflammatory responses through induction of HO-1 and NQO1 expression.

Systematic analysis of the expression profile of non-coding RNAs involved in ischemia/reperfusion-induced acute kidney injury in mice using RNA sequencing

Acute kidney injury (AKI) is a common and serious disease characterized by a rapid decline in renal function and has an unacceptably high mortality rate with no effective treatment beyond supportive care. AKI can be induced by many factors such as ischemia/reperfusion (IR), sepsis, and drug-induced nephrotoxicity. However, the molecular mechanisms of AKI are poorly understood. A non-coding RNA (ncRNA) is a RNA molecule that is not translated into a protein. NcRNAs play multiple roles in cellular processes, and mutations or imbalances of these molecules within the body can cause a variety of diseases. Although growing evidence has supported the key role of ncRNAs in AKI, the specific mechanism remains largely unknown. In this study, the second-generation gene sequencing was performed to investigate the expression patterns of ncRNAs, including microRNA (miRNA), long non-coding RNAs, and circular RNAs, in the kidneys of mice subjected to IR-induced AKI. This information will contribute to future research of the mechanism of ncRNAs in the pathogenesis of AKI and facilitate the identification of novel therapeutic targets of ncRNAs.

Nephrotoxicity Induced by Cisplatin Intake in Experimental Rats and Therapeutic Approach of Using Mesenchymal Stem Cells and Spironolactone

Chronic kidney disease may lead to subsequent tissue fibrosis. However, many factors can combat injurious stimuli in these tissues aiming to repair, heal, and alleviate any disturbance. Chemokines release, migration of inflammatory cells to the affected site, and activation of fibroblasts for the production of extracellular matrix are commonly observed in this disease. In the last years, many studies have focused on spironolactone (SPL), a mineralocorticoid receptor antagonist, and its pharmacological effects. In the present study, SPL was selected as an anti-inflammatory agent to combat nephrotoxicity and renal fibrosis induced by cisplatin. Mesenchymal stem cells (MSCs) were also selected in addition as a referring agent. Renal fibrosis induced by cisplatin intake significantly increased creatinine, urea, nuclear factor kappa B, insulin-like growth factor-1, fibroblast growth factor-23, and kidney malondialdehyde (MDA) content. Hepatocyte growth factor and renal content of reduced glutathione demonstrated a significant decrease. Histopathological examination of kidney tissues demonstrated marked cellular changes which are correlated with the biochemical results. Oral SPL intake (20 mg/kg/body weight) daily for 4 weeks and MSCs administration (3 × 10⁶ cell/rat) intravenous to the experimental rats resulted in a significant improvement of both the biomarkers studied and the histopathological profile of the renal tissue. Individual administration of spironolactone and MSCs exhibited a marked anti-inflammatory potential and alleviated to a great extent the nephrotoxicity and renal fibrotic pattern induced by cisplatin.

Inhibition of PTEN activity aggravates cisplatin-induced acute kidney injury

Cisplatin (cis-Diamminedichloroplatinum II) has been widely and effectively used in chemotherapy against tumors. Nephrotoxicity due to cisplatin is one of the most common clinical causes of acute kidney injury (AKI), which has a poor prognosis and high mortality. The signaling mechanisms underlying cisplatin-induced AKI are not completely understood. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a tumor suppressor that negatively regulates the cell-survival pathway and is considered a double-edged sword in organ damage. In this study, we examined the effect that inhibiting PTEN activity in experimental models of cisplatin-induced AKI had on the degrees of AKI. Compared with vehicle mice, mice treated with bpV(pic) (specific inhibitor of PTEN) had exacerbated renal damage due to cisplatin-induced AKI. Furthermore, inhibition of PTEN activity increased cell apoptosis in the kidneys of mice induced by cisplatin. More inflammatory cytokines were activated after cisplatin treatment in mice of the bpV(pic)-treated group compared with vehicle mice, and these inflammatory cytokines may be partially derived from bone marrow cells. In addition, inhibiting PTEN activity decreased the phosphorylation of p53 in the pathogenesis of cisplatin-induced AKI. In summary, our study has demonstrated that inhibiting PTEN activity aggravates cisplatin-induced AKI via apoptosis, inflammatory reaction, and p53 signaling pathway. These results indicated that PTEN may serve as a novel therapeutic target for cisplatin-induced AKI.

Physiological aspects of Toll-like receptor 4 activation in sepsis-induced acute kidney injury

Sepsis‐induced acute kidney injury (SI‐AKI) is common and associated with high mortality. Survivors are at increased risk of chronic kidney disease. The precise mechanism underlying SI‐AKI is unknown, and no curative treatment exists. Toll‐like receptor 4 (TLR4) activates the innate immune system in response to exogenous microbial products. The result is an inflammatory reaction aimed at clearing a potential infection. However, the consequence may also be organ dysfunction as the immune response can cause collateral damage to host tissue. The purpose of this review is to describe the basis for how ligand binding to TLR4 has the potential to cause renal dysfunction and the mechanisms by which this may take place in gram‐negative sepsis. In addition, we highlight areas for future research that can further our knowledge of the pathogenesis of SI‐AKI in relation to TLR4 activation. TLR4 is expressed in the kidney. Activation of TLR4 causes cytokine and chemokine release as well as renal leucocyte infiltration. It also results in endothelial and tubular dysfunction in addition to altered renal metabolism and circulation. From a physiological standpoint, inhibiting TLR4 in large animal experimental SI‐AKI significantly improves renal function. Thus, current evidence indicates that TLR4 has the ability to mediate SI‐AKI by a number of mechanisms. The strong experimental evidence supporting a role of TLR4 in the pathogenesis of SI‐AKI in combination with the availability of pharmacological tools to target TLR4 warrants future human studies.

Histone deacetylase–mediated silencing of AMWAP expression contributes to cisplatin nephrotoxicity

Cisplatin-induced acute kidney injury is a serious problem in cancer patients during treatment of solid tumors. Currently, there are no therapies available to treat or prevent cisplatin nephrotoxicity. Since histone deacetylase (HDAC) inhibition augments cisplatin anti-tumor activity, we tested whether HDAC inhibitors can prevent cisplatin-induced nephrotoxicity and determined the underlying mechanism. Cisplatin upregulated the expression of several HDACs in the kidney. Inhibition of HDAC with clinically used trichostatin A suppressed cisplatin-induced kidney injury, inflammation, and epithelial cell apoptosis. Moreover, trichostatin A upregulated the novel anti-inflammatory protein, activated microglia/macrophage WAP domain protein (AMWAP), in epithelial cells which was enhanced with cisplatin treatment. Interestingly, HDAC1 and -2 specific inhibitors are sufficient to potently upregulate AMWAP in epithelial cells. Administration of recombinant AMWAP or its epithelial cell-specific overexpression reduced cisplatin-induced kidney dysfunction. Moreover, AMWAP treatment suppressed epithelial cell apoptosis, and siRNA-based knockdown of AMWAP expression abolished trichostatin A-mediated suppression of epithelial cell apoptosis in vitro. Thus, HDAC-mediated silencing of AMWAP may contribute to cisplatin nephrotoxicity. Hence, HDAC1 and -2 specific inhibitors or AMWAP could be useful therapeutic agents for the prevention of cisplatin nephrotoxicity.

Honey feeding protects kidney against cisplatin nephrotoxicity through suppression of inflammation

Cisplatin is a highly effective chemotherapeutic drug used to treat a wide variety of solid tumors. However, its use was limited due its dose-limiting toxicity to the kidney. Currently, there are no therapies available to treat or prevent cisplatin nephrotoxicity. Honey is a naturally occurring complex liquid and widely used in traditional Ayurvedic medicine to treat many illnesses. However, its effect on cisplatin nephrotoxicity is unknown. To determine the role of honey in cisplatin nephrotoxicity, animals were pretreated orally for a week and then cisplatin was administered. Honey feeding was continued for another 3 days. Our results show that animals with cisplatin-induced kidney dysfunction, as determined by increased serum creatinine, which received honey feeding had less kidney dysfunction. Improved kidney function was associated with better preservation of kidney morphology in honey-treated group as compared to the cisplatin alone-treated group. Interestingly, honey feeding significantly reduced cisplatin-induced tubular epithelial cell death, immune infiltration into the kidney as well as cytokine and chemokine expression and excretion as compared to cisplatin treated animals. Western blot analysis shows that cisplatin-induced increase in phosphorylation of NFkB was completely suppressed with honey feeding. In conclusion, honey feeding protects the kidney against cisplatin nephrotoxicity through suppression of inflammation and NFkB activation.

Hyperbilirubinemia exaggerates endotoxin-induced hypothermia

Systemic inflammation is accompanied by an increased production of reactive oxygen species (ROS) and by either fever or hypothermia (or both). To study aseptic systemic inflammation, it is often induced in rats by the intravenous administration of bacterial lipopolysaccharide (LPS). Knowing that bilirubin is a potent ROS scavenger, we compared responses to LPS between normobilirubinemic Gunn rats (heterozygous, asymptomatic; J/+) and hyperbilirubinemic Gunn rats (homozygous, jaundiced; J/J) to establish whether ROS mediate fever and hypothermia in aseptic systemic inflammation. These two genotypes correspond to undisturbed versus drastically suppressed (by bilirubin) tissue accumulation of ROS, respectively. A low dose of LPS (10 μg/kg) caused a typical triphasic fever in both genotypes, without any intergenotype differences. A high dose of LPS (1,000 μg/kg) caused a complex response consisting of early hypothermia followed by late fever. The hypothermic response was markedly exaggerated, whereas the subsequent fever response was strongly attenuated in J/J rats, as compared to J/+ rats. J/J rats also tended to respond to 1,000 μg/kg with blunted surges in plasma levels of all hepatic enzymes studied (alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase), thus suggesting an attenuation of hepatic damage. We propose that the reported exaggeration of LPS-induced hypothermia in J/J rats occurs via direct inhibition of nonshivering thermogenesis by bilirubin and possibly via a direct vasodilatatory action of bilirubin in the skin. This hypothermia-exaggerating effect might be responsible, at least in part, for the observed tendency of J/J rats to be protected from LPS-induced hepatic damage. The attenuation of the fever response to 1,000 μg/kg could be due to either direct actions of bilirubin on thermoeffectors or the ROS-scavenging action of bilirubin. However, the experiments with 10 μg/kg strongly suggest that ROS signaling is not involved in the fever response to low doses of LPS.

New Therapeutic Concept of NAD Redox Balance for Cisplatin Nephrotoxicity

Cisplatin is a widely used chemotherapeutic agent for the treatment of various tumors. In addition to its antitumor activity, cisplatin affects normal cells and may induce adverse effects such as ototoxicity, nephrotoxicity, and peripheral neuropathy. Various mechanisms such as DNA adduct formation, mitochondrial dysfunction, oxidative stress, and inflammatory responses are closely associated with cisplatin-induced nephrotoxicity; however, the precise mechanism remains unclear. The cofactor nicotinamide adenine dinucleotide (NAD⁺) has emerged as a key regulator of cellular energy metabolism and homeostasis. Recent studies have demonstrated associations between disturbance in intracellular NAD⁺ levels and clinical progression of various diseases through the production of reactive oxygen species and inflammation. Furthermore, we demonstrated that reduction of the intracellular NAD⁺/NADH ratio is critically involved in cisplatin-induced kidney damage through inflammation and oxidative stress and that increase of the cellular NAD⁺/NADH ratio suppresses cisplatin-induced kidney damage by modulation of potential damage mediators such as oxidative stress and inflammatory responses. In this review, we describe the role of NAD⁺ metabolism in cisplatin-induced nephrotoxicity and discuss a potential strategy for the prevention or treatment of cisplatin-induced adverse effects with a particular focus on NAD⁺-dependent cellular pathways.

Hydroxylated fullerene: a potential antiinflammatory and antioxidant agent for preventing mouse preterm birth

OBJECTIVE

Intrauterine infection such as by Escherichia coli and Ureaplasma spp induce placental inflammation and are one of the leading causes of preterm birth. Here we evaluated hydroxylated fullerene (C60[OH]44) for its in vitro antiinflammatory and antioxidant effects against host cellular responses to the ureaplasma toll-like receptor 2 (TLR2) ligand, UPM-1. In addition, we investigated the preventative effects of C60(OH)44 in vivo in a mouse preterm birth model that used UPM-1.

STUDY DESIGN

TLR2-overexpressing cell lines and the primary cultures of mouse peritoneal macrophages were pretreated with C60(OH)44. After UPM-1 addition to the cell lines, the activation of the nuclear factor kappa-light chain-enhancer of activated B cells (NF-kappaB) signaling cascade and the production of reactive oxygen species were monitored. The levels of expression of inflammatory cytokines of interleukin (IL)-6, IL-1β, tumor necrosis factor (TNF)-α, and the production of reactive oxygen species were quantified after stimulation with UPM-1. The in vivo preventative effects of C60(OH)44 on mice preterm birth were evaluated by analyzing the preterm birth rates and fetal survival rates in the preterm birth mouse model with placental histological analyses.

RESULTS

Pretreatment with C60(OH)44 significantly suppressed UPM-1-induced NF-kappaB activation and reactive oxygen species production in TLR2-overexpressing cell lines. In the primary culture of mouse peritoneal macrophages, UPM-1-induced production of reactive oxygen species and the expression of inflammatory cytokines such as IL-6, IL-1β, and TNF-α were significantly reduced by pretreatment with C60(OH)44. In the UPM-1-induced preterm birth mouse model, the preterm birth rate decreased from 72.7% to 18.2% after an injection of C60(OH)44. Placental examinations of the group injected with C60(OH)44 reduced the damage of the spongiotrophoblast layer and reduced infiltration of neutrophils.

CONCLUSION

C60(OH)44 was effective as a preventative agent of preterm birth in mice.