Cisplatin-induced acute renal failure is associated with an increase in the cytokines interleukin (IL)-1beta, IL-18, IL-6, and neutrophil infiltration in the kidney

Podocytes express IL-6 and lipocalin 2/ neutrophil gelatinase-associated lipocalin in lipopolysaccharide-induced acute glomerular injury

Background/Aims

Acute kidney injury (AKI) contributes to significant morbidity and mortality in the intensive care unit (ICU). Plasma levels of interleukin (IL)-6 predict the development of AKI and are associated with higher mortality in ICU patients with AKI. Most studies in AKI have focused on the tubulo-interstitium, despite evidence of glomerular involvement. In the following study, our goals were to investigate the expression of IL-6 and its downstream mediators in septic-induced AKI.

Methods

Podocytes were treated in vitro with lipopolysaccharide (LPS) and mice were treated with LPS, and we evaluated IL-6 expression by real-time PCR, ELISA and in situ RNA hybridization.

Results

Following LPS stimulation, IL-6 is rapidly and highly induced in cultured podocytes and in vivo in glomeruli and infiltrating leukocytes. Surprisingly, in direct response to exogenous IL-6, podocytes produce lipocalin-2/neutrophil gelatinase-associated lipocalin (Lcn2/Ngal). LPS also potently induces Lcn2/Ngal expression in podocytes in culture and in glomeruli in vivo. Intense Lcn2/Ngal expression is also observed in IL-6 knockout mice, suggesting that while IL-6 may be sufficient to induce glomerular Lcn2/Ngal expression, it is not essential.

Conclusions

The glomerulus is involved in septic AKI, and we demonstrate that podocytes secrete key mediators of AKI including IL-6 and Lcn2/Ngal.

(-)-Epigallocatechin-3-gallate protects against NO-induced ototoxicity through the regulation of caspase- 1, caspase-3, and NF-κB activation

Excessive nitric oxide (NO) production is toxic to the cochlea and induces hearing loss. However, the mechanism through which NO induces ototoxicity has not been completely understood. The aim of this study was to gain further insight into the mechanism mediating NO-induced toxicity in auditory HEI-OC1 cells and in ex vivo analysis. We also elucidated whether and how epigallocatechin-3-gallate (EGCG), the main component of green tea polyphenols, regulates NO-induced auditory cell damage. To investigate NO-mediated ototoxicity, S-nitroso-N-acetylpenicillamine (SNAP) was used as an NO donor. SNAP was cytotoxic, generating reactive oxygen species, releasing cytochrome c, and activating caspase-3 in auditory cells. NO-induced ototoxicity also mediated the nuclear factor (NF)-κB/caspase-1 pathway. Furthermore, SNAP destroyed the orderly arrangement of the 3 outer rows of hair cells in the basal, middle, and apical turns of the organ of Corti from the cochlea of Sprague-Dawley rats at postnatal day 2. However, EGCG counteracted this ototoxicity by suppressing the activation of caspase-3/NF-κB and preventing the destruction of hair cell arrays in the organ of Corti. These findings may lead to the development of a model for pharmacological mechanism of EGCG and potential therapies against ototoxicity.

Evaluation of nephrotoxic effects of mycotoxins, citrinin and patulin, on zebrafish (Danio rerio) embryos

Citrinin (CTN) and patulin (PAT) are fungal secondary metabolites which are found in food and feed and showed organotoxicity in mature animals. In this study zebrafish embryos were applied to investigate the developmental toxicity of CTN and PAT on embryonic kidney. In the presence of CTN and PAT, the gross morphology of kidneys from embryos with green fluorescent kidney (wt1b:GFP) was not apparently altered. Histological analysis of CTN-treated embryos indicated cystic glomerular and tubular lesions; a disorganized arrangement of renal cells was also found in the PAT-treated group. From the view point of renal function, dextran clearance abilities of embryos exposed to CTN and PAT were significantly reduced. The damaged renal function caused by CTN could be partially rescued by the administration of pentoxifylline, suggesting the reduction of glomerular blood flow contributes to CTN-induced renal dysfunction. Additionally, CTN induced the expression of proinflammation genes, including COX2a, TNF-α and IL-1β, but failed to modify the levels and distribution of wt1a transcript and Na(+)/K(+)-ATPase protein. In summary, CTN and PAT caused profound nephrotoxicity in histological structure and biological function of zebrafish embryos; the inflammatory pathway and blood rheology may involve in CTN-induced renal impairment.

Genetic modification of mesenchymal stem cells to overexpress CXCR4 and CXCR7 does not improve the homing and therapeutic potentials of these cells in experimental acute kidney injury

The therapeutic potential of bone marrow mesenchymal stem cells (MSCs) in kidney failure has been examined in some studies. However, recent findings indicate that after transplantation, these cells home to kidneys at very low levels. Interaction of stromal derived factor-1 (SDF-1) with its receptor, CXCR4, is of pivotal importance in migration and homing. Recently, CXCR7 has also been recognized as another SDF-1 receptor that interacts with CXCR4 and modulates its functions. In this study, CXCR4 and CXCR7 were separately and simultaneously overexpressed in BALB/c bone marrow MSCs by using a lentiviral vector system and the homing and renoprotective potentials of these cells were evaluated in a mouse model of cisplatin-induced acute kidney injury. Using flow cytometry, immunohistochemistry, and real-time PCR methods for detection of GFP-labeled MSCs, we found that although considerably entrapped in lungs, native MSCs home very rarely to kidneys and bone marrow and this rate cannot be significantly affected by CXCR4 and/or CXCR7 upregulation. Transplantation of neither native nor genetically engineered MSCs ameliorated kidney failure. We concluded that overexpression of CXCR4 and CXCR7 receptors in murine MSCs cannot improve the homing and therapeutic potentials of these cells and it can be due to severe chromosomal abnormalities that these cells bear during ex vivo expansion.

Cytokine production increases and cytokine clearance decreases in mice with bilateral nephrectomy

BACKGROUND

Serum cytokines are increased in patients with acute kidney injury (AKI) and predict increased mortality. It is widely assumed that increased renal production of cytokines is the source of increased serum cytokines; the role of extra-renal cytokine production and impaired renal cytokine clearance is less well studied. We hypothesized that cytokine production in AKI was mononuclear phagocyte dependent, independent of production by the kidneys, and that serum cytokine clearance would be impaired in AKI.

METHODS

Bilateral nephrectomy was used as a model of AKI to assess cytokine production independent of kidney cytokine production. Mononuclear phagocytes were depleted utilizing intravenous (IV) administration of liposome-encapsulated clodronate (LEC). Twenty-three serum cytokines were determined utilizing a multiplex cytokine kit. Proteins for cytokines were determined in the spleen and liver by enzyme-linked immunosorbent assay. Recombinant cytokines were injected by IV into mice with bilateral nephrectomy to determine the effect of absent kidney function on serum cytokine clearance.

RESULTS

Serum interleukin (IL)-6, chemokine (C-X-C motif) ligand 1 (CXCL1), IL-10, IL-1β, monocyte chemotactic protein 1 (MCP-1), IL-5 and eotaxin were increased in the serum of mice after bilateral nephrectomy and were reduced with LEC. Serum IL-12p40 and regulated upon activation, normal T-cell expressed, and secreted (RANTES) were increased after bilateral nephrectomy and were further increased with LEC. Spleen IL-6, CXCL1, IL-10 and IL-1β and liver IL-6 and IL-10 were increased after bilateral nephrectomy. After IV injection, IL-6, CXCL1, IL-10 and IL-1β had a prolonged serum cytokine appearance in mice with bilateral nephrectomy versus sham operation.

CONCLUSIONS

Increased mononuclear phagocyte production and impaired renal clearance contribute to serum cytokine accumulation in AKI, independent of kidney injury. The effect of AKI on cytokine production and clearance may contribute to the increased mortality of patients with AKI.

Immunotherapy for acute kidney injury

Acute renal failure, now referred to as acute kidney injury, is a common and clinically important problem. Acute kidney injury frequently occurs as a result of acute tubular necrosis (ATN), which is often caused by a reduction in systemic blood pressure or renal blood flow (e.g., as observed in severe sepsis or during renal transplantation). The disease course in ATN is variable, including prolonged dialysis-dependence and chronic renal dysfunction, but there is currently no specific therapy for ATN. There is increasing evidence that the inflammatory response in ATN significantly contributes to disease severity and outcome. In this review, we summarize recent developments in the understanding of how the immune system responds to dying cells, and the relevance of these discoveries to ATN. In particular, NLRP3 inflammasome activation and IL-1β-mediated neutrophil recruitment are likely to play a key role and may provide novel therapeutic targets for immunotherapy in ATN.

Signaling through the interleukin-18 receptor α attenuates inflammation in cisplatin-induced acute kidney injury

Interleukin (IL)-18 is produced by leukocytes and renal parenchymal cells (tubular epithelial cells, podocytes, and mesangial cells). The IL-18 receptor (IL-18R) is expressed on these cells in cisplatin-induced acute kidney injury, but the role of IL-18R is unknown. To help define this, we compared IL-18Rα knockout with wild-type mice in cisplatin-induced acute kidney injury and found deteriorated kidney function, tubular damage, increased accumulation of leukocytes (CD4(+) and CD8(+) T-cells, macrophages, and neutrophils), upregulation of early kidney injury biomarkers (serum TNF, urinary IL-18, and KIM-1 levels), and increased expression of pro-inflammatory molecules downstream of IL-18. In vitro, leukocytes from the spleen and kidneys of the knockout mice produced greater amounts of pro-inflammatory cytokines upon stimulation with concanavalin A compared to that in wild-type mice. Levels of the suppressor of cytokine signaling 1 and 3 (negative regulators of cytokine signaling) were reduced in the spleen and kidneys of IL-18Rα-deficient compared to wild-type mice. Adoptive transfer of wild-type splenocytes by IL-18Rα-deficient mice led to decreased cisplatin nephrotoxicity compared to control IL-18Rα-deficient mice. In contrast, anti-IL-18Rα and anti-IL-18Rβ antibody treatment tended to increase cisplatin nephrotoxicity in wild-type mice. Thus, signaling through IL-18Rα activates both inflammation-suppressing and pro-injury pathways in cisplatin-induced acute kidney injury.

Attenuation of cisplatin-induced renal injury by inhibition of soluble epoxide hydrolase involves nuclear factor κB signaling

Acute kidney injury is associated with a significant inflammatory response that has been the target of renoprotection strategies. Epoxyeicosatrienoic acids (EETs) are anti-inflammatory cytochrome P450-derived eicosanoids that are abundantly produced in the kidney and metabolized by soluble epoxide hydrolase (sEH; Ephx2) to less active dihydroxyeicosatrienoic acids. Genetic disruption of Ephx2 and chemical inhibition of sEH were used to test whether the anti-inflammatory effects of EETs, and other lipid epoxide substrates of sEH, afford protection against cisplatin-induced nephrotoxicity. EET hydrolysis was significantly reduced in Ephx2(-/-) mice and was associated with an attenuation of cisplatin-induced increases in serum urea nitrogen and creatinine levels. Histological evidence of renal tubular damage and neutrophil infiltration was also reduced in the Ephx2(-/-) mice. Likewise, cisplatin had no effect on renal function, neutrophil infiltration, or tubular structure and integrity in mice treated with the potent sEH inhibitor 1-adamantan-1-yl-3-(1-methylsulfonyl-piperidin-4-yl-urea) (AR9273). Consistent with the ability of EETs to interfere with nuclear factor-κB (NF-κB) signaling, the observed renoprotection was associated with attenuation of renal NF-κB activity and corresponding decreases in the expression of tumor necrosis factor (TNF) α, TNF receptor (TNFR) 1, TNFR2, and intercellular adhesive molecule-1 before the detection of tubular injury. These data suggest that EETs or other fatty acid epoxides can attenuate cisplatin-induced kidney injury and sEH inhibition is a novel renoprotective strategy.

Immunoassays distinguishing between HNL/NGAL released in urine from kidney epithelial cells and neutrophils

BACKGROUND

The distinction between monomeric human neutrophil lipocalin/neutrophil gelatinase-associated lipocalin (HNL/NGAL), secreted by injured kidney tubular cells, and dimeric HNL/NGAL, released by activated neutrophils, is important to accurately diagnose acute kidney injury (AKI).

METHODS

132 urine samples from 44 intensive care unit (ICU) patients and five urine samples from non-ICU patients with urinary tract infections (UTIs) were analyzed by two monoclonal enzyme-linked immunosorbent assays (ELISA-1 and ELISA-2). The presence of monomeric and/or dimeric HNL/NGAL in each sample was visualized by Western blotting.

RESULTS

The ELISA-1 detected both monomeric and dimeric HNL/NGAL whereas the ELISA-2 almost exclusively detected dimeric HNL/NGAL with an area under the receiver-operating characteristics curve (AuROC) of 0.90. The ELISA-1/ELISA-2 ratio detected the monomeric form with an AuROC of 0.92. In 32 AKI patients, dimer-specific ELISA-2 levels decreased pre-AKI whereas the monomer-specific ELISA-1/ELISA-2 ratio gradually increased beyond AKI diagnosis. High ELISA-2 levels and/or low ELISA-1/ELISA-2 ratios detected a predominance of dimeric HNL/NGAL in urine from the patients with UTIs.

CONCLUSIONS

In combination, our two ELISAs distinguish monomeric HNL/NGAL, produced by the kidney epithelium, from dimeric HNL/NGAL, released by neutrophils during AKI development, as well as reduce the confounding effect of neutrophil involvement when bacteriuria is present.

Eucommiae Cortex Inhibits TNF-α and IL-6 Through the Suppression of Caspase-1 in Lipopolysaccharide-Stimulated Mouse Peritoneal Macrophages

Eucommiae cortex (EC) is used in various traditional Korean medicines in the form of tonics, analgesics, and sedatives. However, the underlying mechanism of its anti-inflammatory effect remains unclear. This study attempts to determine the effects of EC on lipopolysaccharide (LPS)-induced inflammatory responses in mouse peritoneal macrophages. The findings of the study show that EC inhibits the LPS-induced production of tumor necrosis factor-alpha and interleukin-6. Exposure to EC also reduces an inflammation-induced increase in the levels of cyclooxigenase-2 and the production of prostaglandin E 2 and nitric oxide in mouse peritoneal macrophages. Furthermore, EC suppresses the activation of nuclear factor-kappa B and caspase-1. These results provide novel insights into the pharmacological action of EC and indicate that EC has a potential in the treatment of inflammatory diseases.

Cisplatin-induced acute renal failure in mice is mediated by chymase-activated angiotensin-aldosterone system and interleukin-18

Mechanism(s) of cisplatin-induced acute renal failure, as manifested by increases in blood urea nitrogen and creatinine, was evaluated in relation to production and activation of endogenous mediator(s) in mice. In interleukin (IL)-18-deficient (IL-18KO) mice, cisplatin failed to induce acute renal failure. Administration of recombinant IL-18 prior to cisplatin restored acute renal failure in IL-18KO mice. Accumulation of cisplatin in the kidney was not different in IL-18KO and wild-type (WT) mice, but, clearance of cisplatin was more rapid in IL-18KO mice than in WT mice. Cisplatin increased serum levels of aldosterone and angiotensin II in WT mice, but only angiotensin II levels in IL-18 KO mice. Administration of IL-18 augmented plasma levels of aldosterone and angiotensin II in WT mice. Eplerenone, an aldosterone receptor blocker, TY-51469, a chymase inhibitor and PD123319, a selective angiotensin II type 2 (AT2) receptor antagonist, but not benazepril, an angiotensin-converting enzyme inhibitor, and candesartan, a selective angiotensin II type 1 (AT1) receptor antagonist improved acute renal failure caused by cisplatin, confirming involvement of IL-18, aldosterone and angiotensin II in cisplatin-induced, chymase-dependent acute renal failure in mice. These results show that IL-18, aldosterone and angiotensin II synergistically act to prolong the accumulation of cisplatin in the kidney, leading to acute renal failure. Combined therapy with inhibitors for chymase and aldosterone receptors or AT2 receptors might reduce acute renal failure induced by cisplatin.

Poly(ADP-ribose) polymerase 1 activation is required for cisplatin nephrotoxicity

Apoptosis, necrosis, and inflammation are hallmarks of cisplatin nephrotoxicity; however, the role and mechanisms of necrosis and inflammation remains undefined. As poly(ADP-ribose) polymerase 1 (PARP1) inhibition or its gene deletion is renoprotective in several renal disease models, we tested whether its activation may be involved in cisplatin nephrotoxicity. Parp1 deficiency was found to reduce cisplatin-induced kidney dysfunction, oxidative stress, and tubular necrosis, but not apoptosis. Moreover, neutrophil infiltration, activation of nuclear factor-κB, c-Jun N-terminal kinases, p38 mitogen-activated protein kinase, and upregulation of proinflammatory genes were all abrogated by Parp1 deficiency. Using proximal tubule epithelial cells isolated from Parp1-deficient and wild-type mice and pharmacological inhibitors, we found evidence for a PARP1/Toll-like receptor 4/p38/tumor necrosis factor-α axis following cisplatin injury. Furthermore, pharmacological inhibition of PARP1 protected against cisplatin-induced kidney structural/functional damage and inflammation. Thus, our findings suggest that PARP1 activation is a primary signal and its inhibition/loss protects against cisplatin-induced nephrotoxicity. Targeting PARP1 may offer a potential therapeutic strategy for cisplatin nephrotoxicity.

Cisplatin-induced nephrotoxicity and targets of nephroprotection: an update

Cisplatin is a highly effective antitumor agent whose clinical application is limited by the inherent nephrotoxicity. The current measures of nephroprotection used in patients receiving cisplatin are not satisfactory, and studies have focused on the investigation of new possible protective strategies. Many pathways involved in cisplatin nephrotoxicity have been delineated and proposed as targets for nephroprotection, and many new potentially protective agents have been reported. The multiple pathways which lead to renal damage and renal cell death have points of convergence and share some common modulators. The most frequent event among all the described pathways is the oxidative stress that acts as both a trigger and a result. The most exploited pathways, the proposed protective strategies, the achievements obtained so far as well as conflicting data are summarized and discussed in this review, providing a general view of the knowledge accumulated with past and recent research on this subject.

Depletion of macrophages and dendritic cells in ischemic acute kidney injury

BACKGROUND

Inflammation is thought to play a role in ischemic acute kidney injury (AKI). We have demonstrated that macrophage and dendritic cell depletion, using liposome-encapsulated clodronate (LEC), is protective against ischemic AKI.

METHODS

To determine whether macrophages or dendritic cells or both play a role in ischemic AKI, we performed ischemic AKI in CD11b-DTR mice that have a diphtheria toxin (DT)-induced depletion of CD11b cells (macrophages) and CD11c-DTR mice that have a DT-induced depletion of CD11c cells (dendritic cells).

RESULTS

While LEC-treated animals had a significant functional protection from AKI, CD11b-DTR and CD11c-DTR mice were not protected against AKI despite a similar degree of renal macrophage and dendritic cell depletion. Proinflammatory cytokines are known to play a role in ischemic AKI. To determine the possible reasons for the lack of protection in CD11b-DTR and CD11c-DTR mice compared to LEC-treated mice, 32 cytokines/chemokines were measured in these mice. Of the cytokines/chemokines measured, IL-6, MCP-1, GMCSF, IL-1β and CXCL1 (also known as IL-8 in humans or KC in mice) showed significant differences in the LEC-treated, CD11b-DTR and CD11c-DTR mice. MCP-1 and CXCL1 (known mediators of AKI), and also GMCSF and IL-1β were increased in AKI and decreased in LEC-treated AKI but not AKI in CD11b-DTR or CD11c-DTR mice.

CONCLUSIONS

These findings suggest that LEC-mediated protection from AKI is not simply mediated by depletion of renal macrophage or dendritic cell subpopulations. Protection against AKI in LEC-treated compared to CD11b-DTR or CD11c-DTR mice may be partially explained by differences in proinflammatory cytokine profiles.

Retracted: Modulation of p53 /Akt / phosphatase and tensin homolog expression by esculetin potentiates the anticancer activity of cisplatin and prevents its nephrotoxicity

This article has been retracted at the request of Editor‐in‐Chief and Authors, and is available online only.

The following article from Cancer Science , ‘Modulation of p53/Akt/phosphatase and tensin homolog expression by esculetin potentiates the anticancer activity of cisplatin and prevents its nephrotoxicity’ (doi: 10.1111/j.1349‐7006.2011.02091.x), by Kulbhushan Tikoo, Abhijit Babaji Shinde, Chanchal Gupta and Gopabandhu Jena, published online on 18 October 2011 in Wiley Online Library (http://onlinelibrary.wiley.com ), has been retracted by agreement between the authors, the journal Editor in Chief, Yusuke Nakamura, and Blackwell Publishing Asia Pty Ltd. The retraction has been agreed due to inappropriate image utilization in relation to Figure 2.

Yusuke Nakamura 
Editor‐in‐Chief 
Cancer Science

Mast cells mediate acute kidney injury through the production of TNF

Leukocyte recruitment contributes to acute kidney injury (AKI), but the mechanisms by which leukocytes promote injury are not completely understood. The degranulation of mast cells releases inflammatory molecules, including TNF, but whether these cells participate in the pathogenesis of AKI is unknown. Here, we induced AKI with cisplatin in mast cell-deficient and wild-type mice. Compared with wild-type mice, deficiency of mast cells attenuated renal injury, reduced serum levels of TNF, and reduced recruitment of leukocytes to the inflamed kidney. Mast cell-deficient mice also exhibited significantly lower intrarenal expression of leukocyte chemoattractants. Mast cell-deficient mice reconstituted with mast cells from wild-type mice exhibited similar cisplastin-induced renal damage and serum levels of TNF as wild-type mice. In contrast, mast cell-deficient mice reconstituted with mast cells from TNF-deficient mice continued to demonstrate significant attenuation of cisplatin-induced renal injury. Furthermore, the mast-cell stabilizer sodium chromoglycate also significantly abrogated renal injury in this model of AKI. Taken together, these results suggest that mast cells mediate AKI through the production of TNF.

Montelukast ameliorates kidney function and urinary bladder sensitivity in experimentally induced renal dysfunction in rats

Effect of montelukast on the renal dysfunction induced by cisplatin was investigated. A single dose of cisplatin (7 mg/kg, i.p.) induced nephrotoxicity, which was manifested by increasing the sensitivity of isolated urinary bladder rings to acetylcholine (ACh) together with a significant elevation of serum creatinine, blood urea nitrogen, and lactate dehydrogenase. On the other hand, serum albumin was significantly decreased. Moreover, renal dysfunction was further confirmed by a significant increase in lipid peroxides that were measured as malondialdehyde (MDA) in kidney tissue homogenate. Kidney reduced glutathione (GSH) content and superoxide dismutase (SOD) activity were measured, which were decreased and increased, respectively. Administration of montelukast (10 mg/kg/day, p.o.) 5 days before and 5 days after cisplatin injection significantly ameliorated the renotoxic effects of cisplatin, as judged by a significant reduction in the responses of isolated bladder rings to ACh. The deleterious changes induced by cisplatin treatment in kidney function parameters and oxidative stress markers were significantly mitigated by montelukast treatment.

CONCLUSION

Montelukast may be a beneficial remedy for cisplatin-induced renal dysfunction.

Inactivation of cystein-aspartic acid protease (caspase)-1 by saikosaponin A

This work investigates the anti-inflammatory mechanism of saikosaponin A (SA), a major component of Bupleurum falcatum LINNE. SA significantly inhibited phorbol myristate acetate (PMA) plus A23187-induced the production and expression of interleukin (IL)-6 and tumor necrosis factor (TNF)-α in human mast cell (HMC)-1 cells. SA suppressed PMA plus A23187-induced phosphorylation of extracellular signal-regulated kinase and p38. When HMC-1 cells were treated with SA, translocation of nuclear factor (NF)-κB/Rel A into nucleus and degradation of inhibitor of NF-κB (IκB) in cytoplasm were inhibited. SA decreased PMA plus A23187-induced cysteine-aspartic acid protease (caspase)-1 activity. IL-1β production was also inhibited by SA. Finally, SA significantly decreased the number of nasal rubs and serum TNF-α level in the ovalbumin-sensitized allergic rhinitis mouse model. The underlying mechanism involves, at least in part, inactivation of caspase-1, which provides new evidence for therapeutic application of SA to target inflammatory processes.

IL-33 exacerbates acute kidney injury

Inflammation contributes to the pathogenesis of acute kidney injury (AKI). IL-33 is a proinflammatory cytokine, but its role in AKI is unknown. Here we observed increased protein expression of full-length IL-33 in the kidney following induction of AKI with cisplatin. To determine whether IL-33 promotes injury, we administered soluble ST2 (sST2), a fusion protein that neutralizes IL-33 activity by acting as a decoy receptor. Compared with cisplatin-induced AKI in untreated mice, mice treated with sST2 had fewer CD4 T cells infiltrate the kidney, lower serum creatinine, and reduced acute tubular necrosis (ATN) and apoptosis. In contrast, administration of recombinant IL-33 (rIL-33) exacerbated cisplatin-induced AKI, measured by an increase in CD4 T cell infiltration, serum creatinine, ATN, and apoptosis; this did not occur in CD4-deficient mice, suggesting that CD4 T cells mediate the injurious effect of IL-33. Wildtype mice that received cisplatin and rIL-33 also had higher levels of the proinflammatory chemokine CXCL1, which CD T cells produce, in the kidney compared with CD4-deficient mice. Mice deficient in the CXCL1 receptor also had lower serum creatinine, ATN, and apoptosis than wildtype mice following cisplatin-induced AKI. Taken together, IL-33 promotes AKI through CD4 T cell-mediated production of CXCL1. These data suggest that inhibiting IL-33 or CXCL1 may have therapeutic potential in AKI.

Effect of erythropoietin therapy on the progression of cisplatin induced renal injury in rats

Cisplatin is one of the most important chemotherapeutic agents useful in the treatment of a variety of solid tumors; however, it has several side effects such as nephrotoxicity. In the present study, the effect of rhEPO on acute kidney injury induced by i.p. injection of rats with 9.0 mg/kg cisplatin was studied. It was observed that EPO treated group showed a significantly lower rate in the extent and severity of the histological signs of kidney injury than untreated one. This is attributed to (i) a decrease in the elevated oxidative and nitrosative stress markers, (ii) reduction of the expression of VEGF, HO-1 and iNOS as well as (iii) improvement of Bcl2 immunoreaction in most tubular cells. Thus, EPO may be one of the futures therapeutic possibilities to overcome the side effects of anti-cancer drugs induced acute renal injury through various mechanisms including down regulation of vascular endothelial growth factor (VEGF), hemeoxygenase-1 (HO-1) and inducible nitric oxide synthase (iNOS) expressions in addition to stimulation of tubular cell regeneration.

Celecoxib, a selective cyclooxygenase-2 inhibitor, attenuates renal injury in a rat model of Cisplatin-induced nephrotoxicity

BACKGROUND

Cisplatin is an effective chemotherapeutic agent successfully used in the treatment of a wide range of tumors. Nevertheless, nephrotoxicity has restricted its clinical use. Recent studies have strongly suggested that inflammatory mechanisms may play an important role in the pathogenesis of cisplatin nephrotoxicity. Celecoxib, a selective cyclooxygenase-2 inhibitor used as anti-inflammatory, may therefore have a protective effect on cisplatin-induced renal injury.

METHODS

In the present study, rats were injected intraperitoneally with a single dose of cisplatin (7 mg/kg) and/or celecoxib (30 mg/kg) for 5 days.

RESULTS

Nephrotoxicity manifested biochemically by elevations in serum creatinine, blood urea nitrogen, and proteinuria, and an increase in kidney weight as a percentage of total body weight. In addition, a marked decrease in serum albumin was observed. Lipid peroxidation in the kidney was monitored by measuring the malondialdehyde level and glutathione content, which were increased and depleted, respectively. Administration of celecoxib with cisplatin attenuated cisplatin-induced changes in kidney function parameters and oxidative stress markers. Histopathological examination of the kidney confirmed these results.

CONCLUSION

In conclusion, this study indicates that celecoxib may be a promising drug for clinical use as a nephroprotectant against cisplatin-induced nephrotoxicity.

Stem cell-conditioned medium does not protect against kidney failure

Paracrine secretion of mediators may be the main route by which stem cells protect against injuries. Stem cells commonly secrete different bioactive molecules. In this study, we examined the hypothesis that administration of conditioned media of stem cells can diminish the burden of kidney injury. A mouse model of cisplatin-induced nephropathy was developed to test the putative renoprotective effects of conditioned media of human umbilical cord blood USSCs (unrestricted somatic stem cells) as well as mouse bone marrow MSCs (mesenchymal stem cells). None of these two types of conditioned medium could protect against kidney failure in terms of serum urea and creatinine, histopathologic examinations and physical activity score. Neither MSC- nor USSC-conditioned media were effective in protecting against kidney injury in our study. Possible explanations for our observations are offered, and related literature is reviewed.

Role of IL-1α in cisplatin-induced acute renal failure in mice

BACKGROUND/AIMS

For unknown reasons, caspase-1 -/- mice, protected against cisplatin-induced acute renal failure (ARF), are deficient in interleukin (IL)-1α. We thus asked whether IL-1α deficiency underlies the mechanism of protection against cisplatin-induced ARF in these mice.

METHODS

Cisplatin (30 mg/kg) was injected intraperitoneally into wild-type C57BL/6 mice to produce a cisplatin-induced model of ARF. IL-1α was measured in control vehicle- and cisplatin-treated wild-type animals. We also examined whether IL-1α -/- mice were similarly protected against cisplatin-induced ARF. Additionally, infiltration of CD11b- and CD49b-positive cells, as markers of macrophages, natural killer, and natural killer T cells (pan-NK cells), was investigated in wild-type and IL-1α -/- mice.

RESULTS

Compared with vehicle-treated mice, renal IL-1α increased in cisplatin-treated wild-type mice beginning on day 1. IL-1α -/- mice were shown to be protected against cisplatin-induced ARF. No significant difference in the infiltration of neutrophils or CD11b- and CD49b-positive cells were observed between wild-type and IL-1α -/- mice.

CONCLUSIONS

Mice deficient in IL-1α are protected against cisplatin-induced ARF. The lack of IL-1α may explain, at least in part, the protection against cisplatin-induced ARF observed in caspase-1 -/- mice. Investigation of the protective mechanism (s) in IL-1α -/- mice in cisplatin-induced ARF merits further study.

Necrotic concentrations of cisplatin activate the apoptotic machinery but inhibit effector caspases and interfere with the execution of apoptosis

Cisplatin is a chemotherapeutic drug whose cytotoxicity is key to its therapeutic and side effects. Nephrotoxicity, mainly due to renal tubular injury, poses its most important therapeutic limitation. Tubular necrosis is derived from epithelial cell death by apoptosis and necrosis in the proximal and distal tubuli. The mode of cell death has been related to drug concentration, with necrosis occurring with high concentrations and apoptosis with lower concentrations. To fully understand the toxic effects of cisplatin to potentially improve its pharmaco-toxicological profile, it is necessary to unravel the cellular events and signaling pathways implicated in the appearance of both modes of cell death. We used cultured human lymphoma and renal tubule cells to investigate the biochemical and phenotypic characteristics of the death mode induced by increasing concentrations of cisplatin. Our results indicate that pronecrotic concentrations of cisplatin early activate the apoptotic machinery, which is in turn directly blocked by cisplatin at the level of effector caspases. Aborted apoptosis induces a death phenotype lacking some typical characteristics of this process, which more closely resembles necrosis. Furthermore, unidentified Bcl-2- and mitochondria-independent pathways are induced by pronecrotic and not by proapoptotic concentrations of cisplatin. Cisplatin-induced cell necrosis is the result of an aborted apoptosis at the level of effector caspases. Yet, Bcl-2-independent effects lead to cell death, which may pose potential targets for pharmacological intervention aimed at reducing cisplatin nephrotoxicity.

Emergence of biomarkers in nephropharmacology

Blood-urea nitrogen, serum creatinine and urine output have long been used as markers of kidney function despite their known limitations. In the past few years, a number of novel biomarkers have been identified in the urine and blood that can detect kidney injury early. Although, to date, none of these biomarkers are in clinical use, many have been validated as reliable and sensitive, allowing detection of kidney injury before serum creatinine levels rise and urine output drops. These markers have been evaluated in great detail in animal models and to a lesser extent in humans in postcardiopulmonary bypass and sepsis. There is relatively scarse data on the use of these biomarkers in the detection of kidney injury associated with the use of pharmacologic agents. The purpose of this article is to summarize these data and highlight the potential utility of these biomarkers in nephropharmacology.

Vanillic acid inhibits inflammatory mediators by suppressing NF-κB in lipopolysaccharide-stimulated mouse peritoneal macrophages

Vanillic acid is a benzoic acid derivative that is used as a flavoring agent. It is an oxidized form of vanillin. At present, the mechanisms by which vanillic acid exerts its anti-inflammatory effects are incompletely understood. In this study, we attempted to determine the effects of vanillic acid on lipopolysaccharide (LPS)-induced inflammatory responses in mouse peritoneal macrophages. Our findings indicate that vanillic acid inhibits LPS-induced production of tumor necrosis factor (TNF)-α and interleukin (IL)-6. During the inflammatory process, the levels of cyclooxygenase (COX)-2 and nitric oxide (NO) increased in mouse peritoneal macrophages, but vanillic acid suppressed both the enhanced levels of COX-2 and the production of prostaglandin E(2) and NO. Moreover, vanillic acid suppressed the activation of nuclear factor-kappa B (NF-κB) and caspase-1. These results provide novel insights into the pharmacological actions of vanillic acid and are indicative of the potential use of this molecule in the treatment of inflammatory diseases.

Human marrow-derived mesenchymal stromal cells decrease cisplatin renotoxicity in vitro and in vivo and enhance survival of mice post-intraperitoneal injection

Acute kidney injury (AKI) can occur from the toxic side-effects of chemotherapeutic agents such as cisplatin. Bone marrow-derived mesenchymal stromal cells (MSCs) have demonstrated wide therapeutic potential often due to beneficial factors they secrete. The goal of this investigation was to evaluate in vitro the effect of human MSCs (hMSCs) secretome on cisplatin-treated human kidney cells, and in vivo the consequence of hMSCs intraperitoneal (ip) implantation in mice with AKI. Our results revealed that hMSCs-conditioned media improved survival of HK-2 human proximal tubular cells exposed to cisplatin in vitro. This enhanced survival was linked to increased expression of phosphorylated Akt (Ser473) and was reduced by a VEGF-neutralizing antibody. In vivo testing of these hMSCs established that ip administration in NOD-SCID mice decreased cisplatin-induced kidney function impairment, as demonstrated by lower blood urea nitrogen levels and higher survival. In addition, blood phosphorous and amylase levels were also significantly decreased. Moreover, hMSCs reduced the plasma levels of several inflammatory cytokines/chemokines. Immunohistochemical examination of kidneys showed less apoptotic and more proliferating cells. Furthermore, PCR indicated the presence of hMSCs in mouse kidneys, which also showed enhanced expression of phosphorylated Akt. In conclusion, our study reveals that hMSCs can exert prosurvival effects on renal cells in vitro and in vivo, suggests a paracrine contribution for kidney protective abilities of hMSCs delivered ip, and supports their clinical potential in AKI.

Mechanisms of Cisplatin nephrotoxicity

Cisplatin is a widely used and highly effective cancer chemotherapeutic agent. One of the limiting side effects of cisplatin use is nephrotoxicity. Research over the past 10 years has uncovered many of the cellular mechanisms which underlie cisplatin-induced renal cell death. It has also become apparent that inflammation provoked by injury to renal epithelial cells serves to amplify kidney injury and dysfunction in vivo. This review summarizes recent advances in our understanding of cisplatin nephrotoxicity and discusses how these advances might lead to more effective prevention.

CB1 cannabinoid receptors promote oxidative/nitrosative stress, inflammation and cell death in a murine nephropathy model

BACKGROUND AND PURPOSE

Accumulating recent evidence suggests that cannabinoid-1 (CB(1)) receptor activation may promote inflammation and cell death and its pharmacological inhibition is associated with anti-inflammatory and tissue-protective effects in various preclinical disease models, as well as in humans.

EXPERIMENTAL APPROACH

In this study, using molecular biology and biochemistry methods, we have investigated the effects of genetic deletion or pharmacological inhibition of CB(1) receptors on inflammation, oxidative/nitrosative stress and cell death pathways associated with a clinically relevant model of nephropathy, induced by an important chemotherapeutic drug cisplatin.

RESULTS

Cisplatin significantly increased endocannabinoid anandamide content, activation of p38 and JNK mitogen-activated protein kinases (MAPKs), apoptotic and poly (ADP-ribose)polymerase-dependent cell death, enhanced inflammation (leucocyte infiltration, tumour necrosis factor-alpha and interleukin-1beta) and promoted oxidative/nitrosative stress [increased expressions of superoxide-generating enzymes (NOX2(gp91phox), NOX4), inducible nitric oxide synthase and tissue 4-hydroxynonenal and nitrotyrosine levels] in the kidneys of mice, accompanied by marked histopathological damage and impaired renal function (elevated creatinine and serum blood urea nitrogen) 3 days following its administration. Both genetic deletion and pharmacological inhibition of CB(1) receptors with AM281 or SR141716 markedly attenuated the cisplatin-induced renal dysfunction and interrelated oxidative/nitrosative stress, p38 and JNK MAPK activation, cell death and inflammatory response in the kidney.

CONCLUSIONS AND IMPLICATIONS

The endocannabinoid system through CB(1) receptors promotes cisplatin-induced tissue injury by amplifying MAPK activation, cell death and interrelated inflammation and oxidative/nitrosative stress. These results also suggest that inhibition of CB(1) receptors may exert beneficial effects in renal (and most likely other) diseases associated with enhanced inflammation, oxidative/nitrosative stress and cell death.

Urine interleukin-6 is an early biomarker of acute kidney injury in children undergoing cardiac surgery

Introduction

Interleukin-6 (IL-6) is a proinflammatory cytokine that increases early in the serum of patients with acute kidney injury (AKI). The aim of this study was to determine whether urine IL-6 is an early biomarker of AKI and determine the source of urine IL-6. Numerous proteins, including cytokines, are filtered by the glomerulus and then endocytosed and metabolized by the proximal tubule. Since proximal tubule injury is a hallmark of AKI, we hypothesized that urine IL-6 would increase in AKI due to impaired proximal tubule metabolism of filtered IL-6.

Methods

Urine was collected in 25 consecutive pediatric patients undergoing cardiac bypass surgery (CPB). AKI was defined as a 50% increase in serum creatinine at 24 hours (RIFLE (Risk, Injury, Failure, Loss, End stage), R). Mouse models of AKI and freshly isolated proximal tubules were also studied.

Results

Urine IL-6 increased at six hours in patients with AKI versus no AKI (X² = 8.1750; P < 0.0042). Urine IL-6 > 75 pg/mg identified AKI with a sensitivity of 88%. To assess whether increased urine IL-6 occurs in functional versus structural renal failure, mouse models of pre-renal azotemia after furosemide injection (no tubular injury), ischemic AKI (tubular injury) and cisplatin AKI (tubular injury) were studied. Urine IL-6 did not significantly increase in pre-renal azotemia but did increase in ischemic and cisplatin AKI. To determine if circulating IL-6 appears in the urine in AKI, recombinant human (h)IL-6 was injected intravenously and urine collected for one hour; urine hIL-6 increased in ischemic AKI, but not pre-renal azotemia. To determine the effect of AKI on circulating IL-6, serum hIL-6 was determined one hour post-intravenous injection and was increased in ischemic AKI, but not pre-renal azotemia. To directly examine IL-6 metabolism, hIL-6 was added to the media of normal and hypoxic isolated proximal tubules; hIL-6 was reduced in the media of normal versus injured hypoxic proximal tubules.

Conclusions

Urine IL-6 increases early in patients with AKI. Animal studies demonstrate that failure of proximal tubule metabolism of IL-6 results in increased serum and urine IL-6. Impaired IL-6 metabolism leading to increased serum IL-6 may contribute to the deleterious systemic effects and increased mortality associated with AKI.

Follistatin-like 1 regulates renal IL-1β expression in cisplatin nephrotoxicity

Follistatin-like 1 (FSTL1) is a secreted protein with homology to both Follistatin and the SPARC/BM40 family of matricellular proteins. In this study, we sought to determine the expression patterns of Fstl1 and its cognate receptor Dip2a in the adult, and to assess the consequences of Fstl1 inactivation on development and homeostasis of the kidney. We find that FSTL1 circulates at high levels in both the human and the mouse and that it is also locally expressed in the loop of Henle in the kidney. To begin to understand the in vivo functions of Fstl1, we generated a mouse mutant using a genetrap approach. The hypomorphic Fstl1 genetrap strain displays a strong reduction in FSTL1 expression at the protein level, but it does not show overt developmental defects. FSTL1 has previously been implicated in diverse disease processes as a regulator of inflammatory cytokine expression, and we therefore evaluated the response of the genetrap strain to cisplatin-mediated acute kidney injury, a disease model with highly cytokine-dependent pathology. We find that although TNF-α and Il6 levels are unchanged relative to wild-type, renal Il-1β expression is increased in genetrap mice following cisplatin treatment. Furthermore, histopatological analysis, expression of the tissue injury marker Havcr1, and measurement of serum creatinine demonstrate that reduction of Fstl1 expression sensitizes the kidney to acute cisplatin nephrotoxicity, suggesting a role for FSTL1-mediated Il-1β suppression in protection of the kidney from acute nephrotoxic injury.

Anti-Inflammatory activity of chrysophanol through the suppression of NF-kappaB/caspase-1 activation in vitro and in vivo

Chrysophanol is a member of the anthraquinone family and has multiple pharmacological effects, but the exact mechanism of the anti-inflammatory effects of chrysophanol has yet to be thoroughly elucidated. In this study, we attempted to determine the effects of chrysophanol on dextran sulfate sodium (DSS)-induced colitis and lipopolysaccharide (LPS)-induced inflammatory responses in mouse peritoneal macrophages. The findings of this study demonstrated that chrysophanol effectively attenuated overall clinical scores as well as various pathological markers of colitis. Additionally, chrysophanol inhibited the production of tumor necrosis factor (TNF)-α, interleukin (IL)-6 and the expression of cyclooxygenase (COX)-2 levels induced by LPS. We showed that this anti-inflammatory effect of chrysophanol is through suppression of the activation of NF-κB and caspase-1 in LPS-stimulated macrophages. These results provide novel insights into the pharmacological actions of chrysophanol as a potential molecule for use in the treatment of inflammatory diseases.

The genome-wide expression profile of Curcuma longa-treated cisplatin-stimulated HEK293 cells

AIM

The rhizome of turmeric, Curcuma longa (CL), is a herbal medicine used in many traditional prescriptions. It has previously been shown that CL treatment showed greater than 47% recovery from cisplatin-induced cell damage in human kidney HEK 293 cells. This study was conducted to evaluate the recovery mechanisms of CL that occur during cisplatin induced nephrotoxicity by examining the genome wide mRNA expression profiles of HEK 293 -cells.

METHOD

Recovery mechanisms of CL that occur during cisplatin-induced nephrotoxicity were determined by microarray, real-time PCR, immunofluorescent confocal microscopy and Western blot analysis.

RESULTS

The results of microarray analysis and real-time PCR revealed that NFκB pathway-related genes and apoptosis-related genes were down-regulated in CL-treated HEK 293 cells. In addition, immunofluorescent confocal microscopy and Western blot analysis revealed that NFκB p65 nuclear translocation was inhibited in CL-treated HEK 293 cells. Therefore, the mechanism responsible for the effects of CL on HEK 293 cells is closely associated with regulation of the NFκB pathway.

CONCLUSION

CL possesses novel therapeutic agents that can be used for the prevention or treatment of cisplatin-induced renal disorders.

Urinary parameters predictive of cisplatin-induced acute renal injury in dogs

A 28-day study was conducted to evaluate changes in urinary cytokine/chemokine expression levels in dogs with renal injury due to administration of cisplatin. Animals (n=17) were administered cisplatin at 0.75 mg/kg/day (i.v.) for five consecutive days. Urine/serum were collected at pre-dosing, 4h post-dosing and on days 2, 3, 4, 8, 10, 14, 16, 18, 21, 23, 25, 28 and unscheduled terminations. Animals were euthanized when serum creatinine (sCr) levels measured at ≥ 1.9 mg/dL, indicating significant loss of renal function (decreased glomerular filtration rate). Relevant clinical observations included lethargy and dehydration. Pre-study sCr levels ranged from 0.6 to 0.8 mg/dL; on days 1 through 4, sCr levels ranged from 0.5 and 1.1mg/dL; and terminal sCr levels ranged from 0.6 and 6.6 mg/dL. Histologically, cisplatin-related renal changes were characterized as proximal tubule dilatation, vacuolization, degeneration, regeneration, and interstitial inflammation. Increased interleukin (IL)-2, IL-8, monocyte chemoattractant protein-1 (MCP-1), granulocyte-macrophage colony-stimulating factor (GMCSF) and keratinocyte-derived chemokine (KC) occurred on days 3 through 4. Increased IL-7 occurred on day 4. This study showed for the first time that inflammatory cytokines/chemokines in urine positively identified acute renal tubular injury in dogs at time points earlier than sCr, a traditional marker of nephrotoxicity.

The regulatory mechanism of β-eudesmol is through the suppression of caspase-1 activation in mast cell-mediated inflammatory response

β-Eudesmol is sesquiterpenoid alcohol which contains the rhizome of Atractylodes lancea. Although it has multiple pharmacological effects, the anti-inflammatory effect of β-eudesmol and its molecular mechanisms are poorly elucidated. In this study, we investigated the regulatory mechanism of β-eudesmol on mast cell-mediated inflammatory response. The results indicated that β-eudesmol inhibited the production and expression of interleukin (IL)-6 on phorbol 12-myristate 13-acetate and calcium ionophore A23187-stimulated human mast cell (HMC). In activated HMC-1 cells, β-eudesmol suppressed activation of p38 mitogen-activated protein kinase (MAPKs) and nuclear factor-κB. In addition, β-eudesmol suppressed the activation of caspase-1 and expression of receptor-interacting protein-2. These results provide new insights into the pharmacological actions of β-eudesmol as a potential molecule for use in therapy in mast cell-mediated inflammatory diseases.

Taming the elephant: Salmonella biology, pathogenesis, and prevention

Salmonella infections continue to cause substantial morbidity and mortality throughout the world. However, recent discoveries and new paradigms promise to lead to novel strategies to diagnose, treat, and prevent Salmonella infections. This review provides an update of the Salmonella field based on oral presentations given at the recent 3rd ASM Conference on Salmonella: Biology, Pathogenesis and Prevention.

Amelioration of cisplatin induced nephrotoxicity by PTY: a herbal preparation

Cisplatin, a chosen drug for cancer treatment, is associated with severe nephrotoxicity, that limits its clinical use. Cisplatin involves enhanced oxidative stress, mitochondrial dysfunction and death of tubular cells. Nephroprotective role of PTY, prepared from methanolic extract of tubers of Pueraria tuberosa D.C., has been studied. PTY was orally given to rats in different doses for seven consecutive days, along with cisplatin (8 mg/kg B.W., i.p.) on 4th day. PTY significantly prevented the rise in serum creatinine, blood urea nitrogen. It prevented the decline in glutathione content, activities of superoxide dismutase and catalase and also prevented DNA damage, tubular swelling, cellular necrosis and protein cast deposition as compared to experimental control group in kidney. These changes were restored to near normal levels by PTY in dose of 40 mg/100 g B.W. Thus, it is proposed that the PTY possesses dose-dependent protective effect against cisplatin induced kidney damages, primarily through its free radical scavenging property.