The peroxisome proliferator-activated receptor-γ agonist pioglitazone protects against cisplatin-induced renal damage in mice

Reserpine alleviates cisplatin-induced acute kidney injury via anti-ferroptosis and cGAS/STING pathway

Cisplatin plays a pivotal role in the chemotherapy treatment of various cancers, but its use is often limited due to its nephrotoxic side effects. Identifying compounds that can mitigate cisplatin-induced nephrotoxicity is therefore of great importance. This study focused on evaluating the protective effects of reserpine against cisplatin-induced acute kidney injury. Reserpine was found to significantly safeguard against kidney damage caused by cisplatin, as indicated by the decreased levels of serum creatinine, blood urea nitrogen, and lactate dehydrogenase induced by cisplatin. Moreover, reserpine improved kidney histology damage caused by cisplatin treatment, with hematoxylin-eosin and periodic acid-Schiff staining revealing notable recovery from renal injury. Mechanistically, reserpine mitigated oxidative stress triggered by cisplatin and exhibits the ability to inhibit ferroptosis both in vivo and in vitro. Additionally, reserpine blocked the activation of the cGAS/STING signaling pathway and the subsequent expression of inflammatory genes, thus reducing inflammation-driven kidney damage. In summary, the findings suggest that reserpine offers a promising new strategy for preventing nephrotoxicity induced by cisplatin.

Roflumilast mitigates cisplatin-induced nephrotoxicity by regulating TNF-α/TNFR1/TNFR2/Fas/Caspase mediated apoptosis and inflammatory signals

PURPOSE

The study aimed to evaluate the effect of roflumilast on modulating TNF-α/Caspase mediated cellular signals in cisplatin-induced nephrotoxicity in rats.

METHODS

The rats (Male Wistar) were divided into five groups: normal control, disease control (cisplatin: 7 mg/kg i.p.), and cisplatin + roflumilast (0.25, 0.5, and 1 mg/kg b.w., p.o.). Cisplatin was administrated to rats on 0 day, and roflumilast treatment was started from the 6th-15th days. Blood and tissue were collected. Tissue was used to measure oxidative stress, such as malondialdehyde, superoxide dismutase, and catalase. Gene expression study involved real-time PCR of key genes linked with inflammation and apoptosis, i.e. Tnf-α, Tnfr1, Tnfr2, Fas, Nfkb, Casp3, Casp8, and Nrf2.

FINDINGS

Cisplatin showed decreased serum creatinine and urea, high albumin, and total protein. Cisplatin elevated the malondialdehyde and reduced superoxide dismutase and catalase activity. Cisplatin also attributed an overexpression of Tnf-α, Tnfr1, Tnfr2, Nfkb, Fas, Casp3, and Casp8, and a decrease in the Nrf2 gene. Roflumilast decreased creatinine and urea and increased albumin and total protein levels. Roflumilast also downregulated the expression of Tnf-α, Tnfr1, Tnfr2, Nfkb, Fas, Casp3, and Casp8 and upregulated the Nrf2 gene expression.

CONCLUSION

Roflumilast manifested as a potential reno-protective agent against cisplatin-induced nephrotoxicity.

Nanotechnology-Based Drug Delivery Systems for Treating Acute Kidney Injury

Acute kidney injury (AKI) is a disease that is characterized by a rapid decline in renal function and has a relatively high incidence in hospitalized patients. Sepsis, renal hypoperfusion, and nephrotoxic drug exposure are the main causes of AKI. The major therapy measures currently include supportive treatment, symptomatic treatment, and kidney transplantation. These methods are supportive treatments, and their results are not satisfactory. Fortunately, many new treatments that markedly improve the AKI therapy efficiency are emerging. These include antioxidant therapy, ferroptosis therapy, anti-inflammatory therapy, autophagy therapy, and antiapoptotic therapy. In addition, the development of nanotechnology has further promoted therapeutic effects on AKI. In this review, we highlight recent advances in the development of nanocarriers for AKI drug delivery. Emphasis has been placed on the latest developments in nanocarrier modification and design. We also summarize the applications of different nanocarriers in AKI treatment. Finally, the advantages and challenges of nanocarrier applications in AKI are summarized, and several nanomedicines that have been approved for clinical trials to treat diverse kidney diseases are listed.

Pioglitazone as a Possible Treatment for Ataxia-Telangiectasia

Ataxia-telangiectasia (AT) is a rare autosomal recessive disorder characterized by immunodeficiency, progressive cerebellar ataxia, and an increased malignancy risk. Cells derived from individuals with AT show multiple defects, including high oxidant and ionizing radiation sensitivities, poor DNA repair, low iron-sulfur cluster levels, and low reduced glutathione. The clinical course of AT is progressive and unrelenting, with most individuals having a survival time of approximately twenty-five years. Presently, AT has no effective treatments, and most patients receive supportive care only. Recently, pioglitazone, a thiazolidinedione class used to treat type 2 diabetes, has been demonstrated to exert beneficial effects on AT cells and on diabetic individuals with AT. Here, I will discuss the possible molecular mechanisms of pioglitazone's favorable effects on the AT phenotype and why it may have utility in treating some aspects of AT.

The Protective Effect of Marsdenia tenacissima against Cisplatin-Induced Nephrotoxicity Mediated by Inhibiting Oxidative Stress, Inflammation, and Apoptosis

Cisplatin (Cis) is considered to be one of the most effective drugs for killing cancer cells and remains a first-line chemotherapeutic agent. However, Cis's multiple toxicities (especially nephrotoxicity) have limited its clinical use. Marsdenia tenacissima (Roxb.) Wight et Arn. (MT), a traditional Chinese medicine (TCM) employed extensively in China, not only enhances the antitumor effect in combination with Cis, but is also used for its detoxifying effect, as it reduces the toxic side effects of chemotherapy drugs. The aim of this study was to explore the therapeutic effect of MT on Cis-induced nephrotoxicity, along with its underlying mechanisms. In this study, liquid-mass spectrometry was performed to identify the complex composition of the extracts of MT. In addition, we measured the renal function, antioxidant enzymes, and inflammatory cytokines in mice with Cis-induced nephrotoxicity and conducted renal histology evaluations to assess renal injury. The expressions of the proteins related to antioxidant, anti-inflammatory, and apoptotic markers in renal tissues was detected by Western blotting (WB). MT treatment improved the renal function, decreased the mRNA expression of the inflammatory factors, and increased the antioxidant enzyme activity in mice. A better renal histology was observed after MT treatment. Further, MT inhibited the expression of the phospho-NFκB p65 protein/NFκB p65 protein (p-p65)/p65, phospho-inhibitor of nuclear factor kappa B kinase beta subunit/inhibitor of nuclear factor kappa B kinase beta subunit (p-IKKβ/IKKβ), Bcl-2-associated X (Bax), and Cleaved Caspase 3/Caspase 3 proteins, while the expression of nuclear factor-erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), Recombinant NADH Dehydrogenase, Quinone 1 (NQO1), and B-cell lymphoma-2 (Bcl-2) was increased. The present study showed that MT ameliorated renal injury, which mainly occurs through the regulation of the Nrf2 pathway, the NF-κB pathway, and the suppression of renal tissue apoptosis. It also suggests that MT can be used as an adjuvant to mitigate the nephrotoxicity of Cis chemotherapy.

Targeted inhibition of CX3CL1 limits podocytes ferroptosis to ameliorate cisplatin-induced acute kidney injury

BACKGROUND

It is widely acknowledged that cisplatin-induced nephrotoxicity hinders its efficacy during clinical therapy. Effective pharmaceutical interventions for cisplatin-induced acute kidney injury (Cis-AKI) are currently lacking. Prior studies have implicated the chemokine CX3CL1 in the development of lipopolysaccharide-induced AKI; however, its specific role in Cis-AKI remains uncertain. This research aimed to comprehensively characterize the therapeutic impact and mechanism of CX3CL1 inhibition on Cis-AKI.

METHODS

This study employed an in vivo Cis-AKI mouse model and in vitro cisplatin-treated podocytes. Kidney pathological changes were assessed using hematoxylin-eosin (HE) and Periodic-Schiff (PAS) staining. Transcriptome changes in mouse kidney tissue post-cisplatin treatment were analyzed through RNA sequencing (RNA-seq) datasets. Evaluation parameters included the expression of inflammatory markers, intracellular free iron levels, ferroptosis-related proteins-solute carrier family 7 member 11 (SLC7A11/XCT) and glutathione peroxidase 4 (GPX4)-as well as lipid peroxidation markers and mitochondrial function proteins. Mitochondrial morphological changes were visualized through transmission electron microscopy. The impact of CX3CL1 on the glucose-regulated protein 78/eukaryotic translation initiation factor 2A/CCAAT enhancer binding protein-homologous protein (GRP78/eIF2α/CHOP) and hypoxia-inducible factor 1-alpha/heme oxygenase-1 (HIF1A/HO-1) pathways in Cis-AKI was assessed via Western Blot and Immunofluorescence experiments, both in vivo and in vitro.

RESULTS

Kidney CX3CL1 levels were elevated following cisplatin injection in wild-type (WT) mice. Cisplatin-treated CX3CL1-Knockout mice exhibited reduced renal histological changes, lowered blood creatinine (Cre) and blood urea nitrogen (BUN) levels, and decreased expression of inflammatory mediators compared to cisplatin-treated WT mice. RNA-seq analysis revealed the modulation of markers associated with oxidative stress and lipid metabolism related to ferroptosis in the kidneys of mice with Cis-AKI. Both the in vivo Cis-AKI mouse model and in vitro cisplatin-treated podocytes demonstrated that CX3CL1 inhibition could mitigate ferroptosis. This effect was characterized by alleviated intracellular iron overload, malondialdehyde (MDA) content, and reactive oxygen species (ROS) production, alongside increased glutathione/glutathione disulfide ratio, superoxide dismutase (SOD), XCT, and GPX4 activity. CX3CL1 inhibition also ameliorated mitochondrial dysfunction and upregulated expression of mitochondrial biogenesis proteins-uncoupling protein (UCP), mitofusin 2 (Mfn2), and peroxisome proliferators-activated receptor γ coactivator l-alpha (PGC1α)-both in vivo and in vitro. Furthermore, CX3CL1 inhibition attenuated cisplatin-induced endoplasmic reticulum (ER) stress in podocytes. Notably, CX3CL1 inhibition reduced cisplatin-induced expression of HIF-1α and HO-1 in vivo and in vitro.

CONCLUSION

Our findings suggest that CX3CL1 inhibition exerts therapeutic effects against Cis-AKI by suppressing podocyte ferroptosis.

Diagnostic potential of serum miR-532-3p as a circulating biomarker for experimental intrinsic drug-induced liver injury by acetaminophen and cisplatin in rats

Evaluating tissue injury largely depends on serum biochemical analysis despite insufficient tissue specificity and low sensitivity. Therefore, attention has been paid to the potential of microRNAs (miRNAs) to overcome the limitations of the current diagnostic tools, as tissue-enriched miRNAs are detected in the blood upon tissue injury. First, using a cisplatin-injected rats, we screened a specific pattern of altered hepatic miRNAs and their target mRNAs. Subsequently, we identified novel liver-specific circulating miRNAs for drug-induced liver injury by comparing miRNA expression changes in organs and serum. RNA sequencing revealed that 32 hepatic miRNAs were differentially expressed (DE) in the cisplatin-treated group. Furthermore, among the 1217 targets predicted using miRDB on these DE-miRNAs, 153 hepatic genes involved in different liver function-related pathways and processes were found to be dysregulated by cisplatin. Next, comparative analyses of the liver, kidneys, and serum DE-miRNAs were conducted to select circulating miRNA biomarker candidates reflecting drug-induced liver injury. Finally, among the four liver-specific circulating miRNAs selected based on their expression patterns in tissue and serum, miR-532-3p was increased in the serum after cisplatin or acetaminophen administration. Our findings suggest that miR-532-3p is potential as a serum biomarker for identifying drug-induced liver injury, leading to the accurate diagnosis.

Pioglitazone treatment increases the cellular acid-labile and protein-bound sulfane sulfur fractions

BACKGROUND

Iron-sulfur clusters play a central role in cellular function and are regulated by the ATM protein. Iron-sulfur clusters are part of the cellular sulfide pool, which functions to maintain cardiovascular health, and consists of free hydrogen sulfide, iron-sulfur clusters, protein bound sulfides, which constitute the total cellular sulfide fraction. ATM protein signaling and the drug pioglitazone share some cellular effects, which led us to examine the effects of this drug on cellular iron-sulfur cluster formation. Additionally, as ATM functions in the cardiovasculature and its signaling may be diminished in cardiovascular disease, we examined pioglitazone in the same cell type, with and without ATM protein expression.

METHODS

We examined the effects of pioglitazone treatment on the total cellular sulfide profile, the glutathione redox state, cystathionine gamma-lyase enzymatic activity, and on double-stranded DNA break formation in cells with and without ATM protein expression.

RESULTS

Pioglitazone increased the acid-labile (iron-sulfur cluster) and bound sulfur cellular fractions and reduced cystathionine gamma-lyase enzymatic activity in cells with and without ATM protein expression. Interestingly, pioglitazone also increased reduced glutathione and lowered DNA damage in cells without ATM protein expression, but not in ATM wild-type cells. These results are interesting as the acid-labile (iron-sulfur cluster), bound sulfur cellular fractions, and reduced glutathione are low in cardiovascular disease.

CONCLUSION

Here we found that pioglitazone increased the acid-labile (iron-sulfur cluster) and bound sulfur cellular fractions, impinges on hydrogen sulfide synthesis, and exerts beneficial effect on cells with deficient ATM protein signaling. Thus, we show a novel pharmacologic action for pioglitazone.

Calcitriol Reduces the Inflammation, Endothelial Damage and Oxidative Stress in AKI Caused by Cisplatin

Cisplatin treatment is one of the most commonly used treatments for patients with cancer. However, thirty percent of patients treated with cisplatin develop acute kidney injury (AKI). Several studies have demonstrated the effect of bioactive vitamin D or calcitriol on the inflammatory process and endothelial injury, essential events that contribute to changes in renal function and structure caused by cisplatin (CP). This study explored the effects of calcitriol administration on proximal tubular injury, oxidative stress, inflammation and vascular injury observed in CP-induced AKI. Male Wistar Hannover rats were pretreated with calcitriol (6 ng/day) or vehicle (0.9% NaCl). The treatment started two weeks before i.p. administration of CP or saline and was maintained for another five days after the injections. On the fifth day after the injections, urine, plasma and renal tissue samples were collected to evaluate renal function and structure. The animals of the CP group had increased plasma levels of creatinine and of fractional sodium excretion and decreased glomerular filtration rates. These changes were associated with intense tubular injury, endothelial damage, reductions in antioxidant enzymes and an inflammatory process observed in the renal outer medulla of the animals from this group. These changes were attenuated by treatment with calcitriol, which reduced the inflammation and increased the expression of vascular regeneration markers and antioxidant enzymes.

Ameliorative impacts of polymeric and metallic nanoparticles on cisplatin-induced nephrotoxicity: a 2011-2022 review

Cisplatin (CDDP) is a well-known platinum-based drug used in the treatment of various malignancies. However, the widespread side effects that this drug leaves on normal tissues make its use limited. Since cisplatin is mainly eliminated from the kidneys, CDDP-induced nephrotoxicity is the most significant dose-limiting complication attributed to cisplatin, which often leads to dose withdrawal. Considering the high efficiency of cisplatin in chemotherapy, finding renoprotective drug delivery systems for this drug is a necessity. In this regard, we can take advantages of different nanoparticle-based approaches to deliver cisplatin into tumors either using passive targeting or using specific receptors. In an effort to find more effective cisplatin-based nano-drugs with less nephrotoxic effect, the current 2011-2022 review study was conducted to investigate some of the nanotechnology-based methods that have successfully been able to mitigate CDDP-induced nephrotoxicity. Accordingly, although cisplatin can cause renal failures through inducing mitochondria dysfunction, oxidative stress, lipid peroxidation and endoplasmic reticulum stress, some CDDP-based nano-carriers have been able to reverse a wide range of these advert effects. Based on the obtained results, it was found that the use of different metallic and polymeric nanoparticles can help renal cells to strengthen their antioxidant systems and stay alive through reducing CDDP-induced ROS generation, inhibiting apoptosis-related pathways and maintaining the integrity of the mitochondrial membrane. For example, nanocurcumin could inhibit oxidative stress and acting as a ROS scavenger. CONPs could reduce lipid peroxidation and pro-inflammatory cytokines. CDDP-loaded silver nanoparticles (AgNPs) could inhibit mitochondria-mediated apoptosis. In addition, tea polyphenol-functionalized SeNPs (Se@TE) NPs could mitigate the increased level of dephosphorylated AKT, phosphorylated p38 MAPK and phosphorylated c-Jun N-terminal kinase (JNK) induced by cisplatin. Moreover, exosomes mitigated cisplatin-induced renal damage through inhibiting Bcl2 and increasing Bim, Bid, Bax, cleaved caspase-9, and cleaved caspase-3. Hence, nanoparticle-based techniques are promising drug delivery systems for cisplatin so that some of them, such as lipoplatins and nanocurcumins, have even reached phases 1-3 trials.

Mapping Adverse Outcome Pathways for Kidney Injury as a Basis for the Development of Mechanism-Based Animal-Sparing Approaches to Assessment of Nephrotoxicity

In line with recent OECD activities on the use of AOPs in developing Integrated Approaches to Testing and Assessment (IATAs), it is expected that systematic mapping of AOPs leading to systemic toxicity may provide a mechanistic framework for the development and implementation of mechanism-based in vitro endpoints. These may form part of an integrated testing strategy to reduce the need for repeated dose toxicity studies. Focusing on kidney and in particular the proximal tubule epithelium as a key target site of chemical-induced injury, the overall aim of this work is to contribute to building a network of AOPs leading to nephrotoxicity. Current mechanistic understanding of kidney injury initiated by 1) inhibition of mitochondrial DNA polymerase γ (mtDNA Polγ), 2) receptor mediated endocytosis and lysosomal overload, and 3) covalent protein binding, which all present fairly well established, common mechanisms by which certain chemicals or drugs may cause nephrotoxicity, is presented and systematically captured in a formal description of AOPs in line with the OECD AOP development programme and in accordance with the harmonized terminology provided by the Collaborative Adverse Outcome Pathway Wiki. The relative level of confidence in the established AOPs is assessed based on evolved Bradford-Hill weight of evidence considerations of biological plausibility, essentiality and empirical support (temporal and dose-response concordance).

The Role of Peroxisome Proliferator-Activated Receptors in Kidney Diseases

Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptor superfamily of ligand-activated transcription factors. Accumulating evidence suggests that PPARs may play an important role in the pathogenesis of kidney disease. All three members of the PPAR subfamily, PPARα, PPARβ/δ, and PPARγ, have been implicated in many renal pathophysiological conditions, including acute kidney injury, diabetic nephropathy, and chronic kidney disease, among others. Emerging data suggest that PPARs may be potential therapeutic targets for renal disease. This article reviews the physiological roles of PPARs in the kidney and discusses the therapeutic utility of PPAR agonists in the treatment of kidney disease.

Natural products: potential treatments for cisplatin-induced nephrotoxicity

Cisplatin is a clinically advanced and highly effective anticancer drug used in the treatment of a wide variety of malignancies, such as head and neck, lung, testis, ovary, breast cancer, etc. However, it has only a limited use in clinical practice due to its severe adverse effects, particularly nephrotoxicity; 20%–35% of patients develop acute kidney injury (AKI) after cisplatin administration. The nephrotoxic effect of cisplatin is cumulative and dose dependent and often necessitates dose reduction or withdrawal. Recurrent episodes of AKI result in impaired renal tubular function and acute renal failure, chronic kidney disease, uremia, and hypertensive nephropathy. The pathophysiology of cisplatin-induced AKI involves proximal tubular injury, apoptosis, oxidative stress, inflammation, and vascular injury in the kidneys. At present, there are no effective drugs or methods for cisplatin-induced kidney injury. Recent in vitro and in vivo studies show that numerous natural products (flavonoids, saponins, alkaloids, polysaccharide, phenylpropanoids, etc.) have specific antioxidant, anti-inflammatory, and anti-apoptotic properties that regulate the pathways associated with cisplatin-induced kidney damage. In this review we describe the molecular mechanisms of cisplatin-induced nephrotoxicity and summarize recent findings in the field of natural products that undermine these mechanisms to protect against cisplatin-induced kidney damage and provide potential strategies for AKI treatment.

Umbelliferone attenuates glycerol-induced myoglobinuric acute kidney injury through peroxisome proliferator-activated receptor-γ agonism in rats

Rhabdomyolysis is a clinical syndrome caused by damage to skeletal muscle, which consequently releases breakdown products into circulation and causes acute kidney injury (AKI) in humans. Intramuscular injection of glycerol mimics rhabdomyolysis and associated AKI. In this study, we explored the role of umbelliferone against glycerol-induced AKI in rats. Kidney function was assessed by measuring serum creatinine, urea, electrolytes, and microproteinuria. Renal oxidative stress was quantified using thiobarbituric acid reactive substances, superoxide anion generation, and reduced glutathione assay. Renal histological changes were determined using periodic acid Schiff and hematoxylin-eosin staining, and immunohistology of apoptotic markers (Bax, Bcl-2) was done. Serum creatine kinase was quantified to assess glycerol-induced muscle damage. Umbelliferone attenuated glycerol-induced change in biochemical parameters, oxidative stress, histological alterations, and renal apoptosis. Pretreatment with bisphenol A diglycidyl ether, a peroxisome proliferator-activated receptor-γ (PPAR-γ) antagonist, attenuated umbelliferone-mediated protection. It is concluded that umbelliferone attenuates glycerol-induced AKI possibly through PPAR-γ agonism in rats.

Protective effects of lutein against vancomycin-induced acute renal injury in mice via upregulation of peroxisome proliferator-activated receptor gamma/nuclear factor erythroid 2-related factor 2 and inhibition nuclear factor-kappaB/caspase 3

Vancomycin, an antibiotic used occasionally as a last line of treatment for methicillin-resistant Staphylococcus aureus, is reportedly associated with nephrotoxicity. This study aimed at evaluating the protective effects of lutein against vancomycin-induced acute renal injury. Peroxisome proliferator-activated receptor gamma (PPARγ) and its associated role in renoprotection by lutein was also examined. Male BALB/c mice were divided into six treatment groups: control with normal saline, lutein (200 mg/kg), vancomycin (250 mg/kg), vancomycin (500 mg/kg), vancomycin (250 mg/kg) with lutein, and vancomycin (500 mg/kg) with lutein groups; they were euthanized after 7 days of treatment. Thereafter, samples of blood, urine, and kidney tissue of the mice were analyzed, followed by the determination of levels of N-acetyl-β-D-glucosaminidase (NAG) in the urine, renal creatine kinase; protein carbonyl, malondialdehyde, and caspase-3 in the kidney; and the expression of PPARγ, nuclear factor erythroid 2-related factor 2 (Nrf2), and nuclear factor-kappaB (NF-κB) in renal tissue. Results showed that the levels of protein carbonyl and malondialdehyde, and the activity of NAG, creatine kinase and caspase-3, were significantly increased in the vancomycin-treatment groups. Moreover, the levels of Nrf2 significantly decreased, while NF-κB expression increased. Lutein ameliorated these effects, and significantly increased PPARγ expression. Furthermore, it attenuated vancomycin-induced histological alterations such as, tissue necrosis and hypertrophy. Therefore, we conclude that lutein protects against vancomycin-induced renal injury by potentially upregulating PPARγ/Nrf2 expression in the renal tissues, and consequently downregulating the pathways: inflammation by NF-κB and apoptosis by caspase-3.

Adult Zebrafish Model for Screening Drug-Induced Kidney Injury

Drug-induced kidney injury is a serious safety issue in drug development. In this study, we evaluated the usefulness of adult zebrafish as a small in vivo system for detecting drug-induced kidney injury. We first investigated the effects of typical nephrotoxicants, gentamicin and doxorubicin, on adult zebrafish. We found that gentamicin induced renal tubular necrosis with increased lysosome and myeloid bodies, and doxorubicin caused foot process fusion of glomerular podocytes. These findings were similar to those seen in mammals, suggesting a common pathogenesis. Second, to further evaluate the performance of the model in detecting drug-induced kidney injury, adult zebrafish were treated with 28 nephrotoxicants or 14 nonnephrotoxicants for up to 4 days, euthanized 24 h after the final treatment, and examined histopathologically. Sixteen of the 28 nephrotoxicants and none of the 14 nonnephrotoxicants caused drug-induced kidney injury in zebrafish (sensitivity, 57%; specificity, 100%; positive predictive value, 100%; negative predictive value, 54%). Finally, we explored genomic biomarker candidates using kidneys isolated from gentamicin- and cisplatin-treated zebrafish using microarray analysis and identified 3 candidate genes, egr1, atf3, and fos based on increased expression levels and biological implications. The expression of these genes was upregulated dose dependently in cisplatin-treated groups and was > 25-fold higher in gentamicin-treated than in the control group. In conclusion, these results suggest that the adult zebrafish has (1) similar nephrotoxic response to those of mammals, (2) considerable feasibility as an experimental model for toxicity studies, and (3) applicability to pathological examination and genomic biomarker evaluation in drug-induced kidney injury.

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.

Stevioside protects against rhabdomyolysis-induced acute kidney injury through PPAR-γ agonism in rats

We explored the potential role of peroxisome proliferator activated receptor-γ (PPAR-γ) in stevioside-mediated renoprotection using rhabdomyolysis-induced acute kidney injury (AKI) model in rats. Rhabdomyolysis refers to intense skeletal muscle damage, which further causes AKI. Glycerol (50% w/v, 8 ml/kg) was injected intramuscularly in rats to induce rhabdomyolysis. After 24 hr, AKI was demonstrated by quantifying serum creatinine, urea, creatinine clearance, microproteinuria, and electrolytes in rats. Further, oxidative stress was measured by assaying thiobarbituric acid reactive substances, generation of superoxide anion, and reduced glutathione levels. Additionally, serum creatine kinase (CK) level was assayed to determine glycerol-induced muscle damage in rats. Pathological changes in rat kidneys were studied using hematoxylin-eosin and periodic acid Schiff staining. Moreover, the expression of apoptotic markers (Bcl-2, Bax) in rat kidneys was demonstrated by immunohistochemistry. Stevioside (10, 25, and 50 mg/kg) was administered to rats, prior to the induction of AKI. In a separate group, bisphenol A diglycidyl ether (BADGE, 30 mg/kg), a PPAR-γ receptor antagonist was given prior to stevioside administration, which was followed by rhabdomyolysis-induced AKI in rats. The significant alteration in biochemical and histological parameters in rats indicated AKI, which was attenuated by stevioside treatment. Pretreatment with BADGE abrogated stevioside-mediated renoprotection, which is suggestive of the involvement of PPAR-γ in its renoprotective effect. In conclusion, stevioside protects against rhabdomyolysis-induced AKI, which may be attributed to modulation of PPAR-γ expression.

A meta-analysis of preclinical studies using antioxidants for the prevention of cisplatin nephrotoxicity: implications for clinical application

Cisplatin is an effective chemotherapeutic drug whose clinical use and efficacy are limited by its nephrotoxicity, which affects mainly the renal tubules and vasculature. It accumulates in proximal and distal epithelial tubule cells and causes oxidative stress-mediated cell death and malfunction. Consequently, many antioxidants have been tested for their capacity to prevent cisplatin nephrotoxicity. In this study, we made a systematic review of the literature and meta-analyzed 152 articles, which tested the nephroprotective effect of isolated compounds or mixtures of natural origin on cisplatin nephrotoxicity in preclinical models. This meta-analysis identified the most effective candidates and examined the efficacy obtained by antioxidants administered by the oral and intraperitoneal routes. By comparing with a recent, similar meta-analysis performed on clinical studies, this article identifies a disconnection between preclinical and clinical research, and contextualizes, discusses, and integrates the existing preclinical information toward the optimized selection of candidates to be further explored (clinical level). Despite proved efficacy, this article discusses the barriers limiting the clinical development of natural mixtures, such as those in extracts from Calendula officinalis flowers and Heliotropium eichwaldii roots. On the contrary, isolated compounds are more straightforward candidates, among which arjunolic acid and quercetin stand out in this meta-analysis.

Sinapic acid attenuates cisplatin-induced nephrotoxicity through peroxisome proliferator-activated receptor gamma agonism in rats

AIM

The aim of this study was to investigate the involvement of peroxisome proliferator-activated receptor gamma (PPAR-γ) in renal protection offered by sinapic acid in cisplatin-induced nephrotoxicity in male rats.

MATERIALS AND METHODS

Nephrotoxicity was induced by single dose of cisplatin (5 mg/kg, intraperitoneal [i.p.]) in rats. Cisplatin-induced nephrotoxicity was assessed by measuring serum creatinine, creatinine clearance, urea, uric acid, potassium, magnesium levels, fractional excretion of sodium, and microproteinuria in rats. Superoxide anion generation, thiobarbituric acid reactive substances, myeloperoxidase activity, and reduced glutathione levels were measured to assess oxidative stress in renal tissues. Hematoxylin and eosin stain showed renal histological changes.

RESULTS

The significant changes in serum and urinary parameters, elevated oxidative stress, and renal histological changes established the induction of nephrotoxicity. Sinapic acid treatment (20 and 40 mg/kg, orally [p.o.]) provides dose-dependent and significant (P < 0.05) nephroprotection against cisplatin-mediated nephrotoxicity in rats. Nephroprotective effect of sinapic acid was abolished by PPAR-γ inhibitor, bisphenol A diglycidyl ether (30 mg/kg, i.p.) in rats.

CONCLUSION

It is concluded that PPAR-γ agonism serves as one of the mechanisms in sinapic acid-mediated renoprotection.

Rosiglitazone Suppresses Calcium Oxalate Crystal Binding and Oxalate-Induced Oxidative Stress in Renal Epithelial Cells by Promoting PPAR-γ Activation and Subsequent Regulation of TGF-β1 and HGF Expression

Peroxisome proliferator-activated receptor- (PPAR-) γ is a ligand-dependent transcription factor, and it has become evident that PPAR-γ agonists have renoprotective effects, but their influence and mechanism during the development of calcium oxalate (CaOx) nephrolithiasis remain unknown. Rosiglitazone (RSG) was used as a representative PPAR-γ agonist in our experiments. The expression of transforming growth factor-β1 (TGF-β1), hepatocyte growth factor (HGF), c-Met, p-Met, PPAR-γ, p-PPAR-γ (Ser112), Smad2, Smad3, pSmad2/3, and Smad7 was examined in oxalate-treated Madin-Darby canine kidney (MDCK) cells and a stone-forming rat model. A CCK-8 assay was used to evaluate the effects of RSG on cell viability. In addition, intracellular reactive oxygen species (ROS) levels were monitored, and lipid peroxidation in renal tissue was detected according to superoxide dismutase and malondialdehyde levels. Moreover, the location and extent of CaOx crystal deposition were evaluated by Pizzolato staining. Our results showed that, both in vitro and in vivo, oxalate impaired PPAR-γ expression and phosphorylation, and then accumulative ROS production was observed, accompanied by enhanced TGF-β1 and reduced HGF. These phenomena could be reversed by the addition of RSG. RSG also promoted cell viability and proliferation and decreased oxidative stress damage and CaOx crystal deposition. However, these protective effects of RSG were abrogated by the PPAR-γ-specific inhibitor GW9662. Our results revealed that the reduction of PPAR-γ activity played a critical role in oxalate-induced ROS damage and CaOx stone formation. RSG can regulate TGF-β1 and HGF/c-Met through PPAR-γ to exert antioxidant effects against hyperoxaluria and alleviate crystal deposition. Therefore, PPAR-γ agonists may be expected to be a novel therapy for nephrolithiasis, and this effect is related to PPAR-γ-dependent suppression of oxidative stress.

Wogonin pre-treatment attenuates cisplatin-induced nephrotoxicity in rats: Impact on PPAR-γ, inflammation, apoptosis and Wnt/β-catenin pathway

Cisplatin, a platinum chemotherapeutic agent, is used in a diversity of malignancies; nevertheless, the excessive nephrotoxicity following cisplatin treatment is the dose-limiting devastating reaction. This study was designed to explore the possible nephroprotective impact of wogonin, a forceful anti-oxidant, anti-inflammatory, and anti-tumor agent, in a rat model of cisplatin-induced renal injury. The potential nephroprotective mechanisms were additionally investigated. Wogonin was given at a dose of 40 mg/kg. Acute nephrotoxicity was indicated by a significant rise in BUN, and serum creatinine levels in cisplatin-injected rats. Also, cisplatin enhanced the lipid peroxidation, diminished GSH, catalase, and PPAR-γ levels. Additionally, cisplatin-injected rats showed a significant rise in tissue levels of IL-1β, TNF-α, NF-kB, and caspase-3 enzymatic activity. Notably, the pre-treatment with wogonin ameliorated the nephrotoxicity indices, oxidative stress, inflammation, and apoptosis induced by cisplatin. Also, wogonin up-regulated PPAR-γ expression. The involvement of Wnt/β-catenin pathway was debatable; however, our findings showed that it was significantly induced by cisplatin. Wogonin pre-treatment markedly attenuated Wnt/β-catenin pathway. Collectively, these findings imply that wogonin is a promising nephroprotective agent that improves the therapeutic index of cisplatin via reducing oxidative stress, inflammation as well as inducing PPAR-γ. Also, Wnt/β-catenin pathway is partially involved in the pathogenesis of cisplatin nephrotoxicity.

PPAR gamma agonist, pioglitazone, rescues liver damage induced by renal ischemia/reperfusion injury

Remote organ damage is the major cause of death in patients with acute kidney injury (AKI) due to renal ischemia reperfusion (IR). Liver is one of the vital organs which are profoundly affected by AKI. The present study aims to investigate the role of peroxisome proliferator activator receptor gamma (PPARγ) in liver damage induced by IR injury in rats. Renal IR was induced by right nephrectomy, occlusion of left renal pedicle for 45 min to induce ischemia, and then reperfusion for 6 or 24 h. The PPARγ agonist, pioglitazone, was given orally for 7 days before renal IR procedure. Animals receiving pioglitazone showed improvement in renal and hepatic functions when compared to IR groups. Renal IR increased renal, hepatic and serum levels of tumor necrosis factor-α (TNF-α) and induced apoptotic cell death in liver. These effects were diminished with pioglitazone. In addition, pioglitazone reduced renal IR-induced oxidative stress in liver. Pioglitazone reduced malondialdehyde (MDA) content and NADPH oxidase mRNA expression and induced further increase in nuclear factor erythroid 2-related factor 2 (Nrf2) expression when compared to IR groups. Furthermore, pioglitazone increased the expression of PPARγ target genes such as renal and hepatic PPARγ1 (Pparg1), hepatic hemoxygenase-1 (Hmox1), and hepatic thioredoxin (TRx). Histological profiles for kidney and liver were also ameliorated with pioglitazone. Hence, PPARγ is a potential target to protect liver in patients with renal IR injury.

Role of peroxisome proliferator-activated receptor-gamma activation on visfatin, advanced glycation end products, and renal oxidative stress in obesity-induced type 2 diabetes mellitus

The present study focused on the role of peroxisome proliferator-activated receptor-gamma (PPAR-γ) activation on renal oxidative damages, serum visfatin, and advanced glycation end products (AGEs) in high-fat diet (HFD)-induced type 2 diabetes mellitus. Following the institutional animal ethics committee guidelines, Wistar rats were categorized into five groups: group 1: fed on a normal rat diet; group 2: HFD-induced obese rats (HFD for 8 weeks); group 3: HFD-fed rats treated with rosiglitazone (RSG; 3 mg/kg orally for 7 days); group 4: T2DM rats induced by HFD and low dose of streptozotocin (i.p. 35 mg/kg); group 5: T2DM rats treated with RSG (3 mg/kg orally for 7 days). Serum levels of AGEs and visfatin, renal damage, and oxidative stress were analyzed. Results showed that HFD-induced obesity and T2DM caused an elevated blood glucose, serum AGEs, visfatin, insulin, urea, creatinine, and tissue malondialdehyde, whereas a decreased catalase and superoxide dismutase activity were observed. The PPAR-γ activation via agonist restored these changes. Our findings suggest that AGEs and visfatin possess an important role in the progression of renal oxidative stress, which can be reduced by the PPAR-γ agonist that impede deleterious effects of HFD and HFD-induced T2DM on renal damage.

Mitochondria as therapeutic targets in acute kidney injury

PURPOSE OF REVIEW

Mitochondria are complex intracellular organelles with a variety of important functions. The kidney tubule is densely packed with mitochondria, and mitochondrial dysfunction is thought to be central to the pathogenesis of acute kidney injury (AKI). Mitochondria therefore represent potential targets for novel therapeutic interventions in AKI.

RECENT FINDINGS

Several mitochondrial targeted approaches have shown promise in recent preclinical studies of AKI, including measures to: reduce oxidative stress within mitochondria; prevent mitochondrial fission and activation of cell death pathways; enhance recycling of damaged mitochondria via autophagy and mitophagy; and accelerate mitochondrial biogenesis postinsult.

SUMMARY

Recent studies show that it is now eminently feasible to pharmacologically manipulate various key aspects of mitochondrial biology in the kidney, and this has much potential for the future treatment of AKI. However, significant hurdles will have to be overcome in the translational pathway for these strategies to successfully migrate to the clinic.

Lobeglitazone, a Novel Peroxisome Proliferator-Activated Receptor γ Agonist, Attenuates Renal Fibrosis Caused by Unilateral Ureteral Obstruction in Mice

BACKGROUND

Renal tubulointerstitial fibrosis is a common feature of the final stage of nearly all cause types of chronic kidney disease. Although classic peroxisome proliferator-activated receptor γ (PPARγ) agonists have a protective effect on diabetic nephropathy, much less is known about their direct effects in renal fibrosis. This study aimed to investigate possible beneficial effects of lobeglitazone, a novel PPARγ agonist, on renal fibrosis in mice.

METHODS

We examined the effects of lobeglitazone on renal tubulointerstitial fibrosis in unilateral ureteral obstruction (UUO) induced renal fibrosis mice. We further defined the role of lobeglitazone on transforming growth factor (TGF)-signaling pathways in renal tubulointerstitial fibrosis through in vivo and in vitro study.

RESULTS

Through hematoxylin/eosin and sirius red staining, we observed that lobeglitazone effectively attenuates UUO-induced renal atrophy and fibrosis. Immunohistochemical analysis in conjunction with quantitative reverse transcription polymerase chain reaction and Western blot analysis revealed that lobeglitazone treatment inhibited UUO-induced upregulation of renal Smad-3 phosphorylation, α-smooth muscle actin, plasminogen activator inhibitor 1, and type 1 collagen. In vitro experiments with rat mesangial cells and NRK-49F renal fibroblast cells suggested that the effects of lobeglitazone on UUO-induced renal fibrosis are mediated by inhibition of the TGF-β/Smad signaling pathway.

CONCLUSION

The present study demonstrates that lobeglitazone has a protective effect on UUO-induced renal fibrosis, suggesting that its clinical applications could extend to the treatment of non-diabetic origin renal disease.

Pioglitazone ameliorates renal ischemia reperfusion injury through NMDA receptor antagonism in rats

The present study investigated the role of N-methyl-D-aspartate (NMDA) receptors in pioglitazone-mediated protection against renal ischemia reperfusion injury (IRI) in rats. Male wistar rats were subjected to 40 min of bilateral renal ischemia followed by reperfusion for 24 h to induce kidney injury. The renal damage was evaluated by measuring serum creatinine, creatinine clearance, blood urea nitrogen, uric acid, electrolytes, and microproteinuria in rats. Oxidative stress in renal tissues was quantified in terms of myeloperoxidase activity, thiobarbituric acid reactive substances, superoxide anion generation, and reduced glutathione level. Hematoxylin-eosin and periodic acid Schiff staining of renal tissues were performed to observe histological changes. Pioglitazone (20 and 40 mg/kg) was administered 1 h prior to ischemia in rats. In separate groups, NMDA agonists, glutamic acid (200 mg/kg), and spermidine (20 mg/kg) were administered 1 h prior to pioglitazone treatment, followed by renal IRI in rats. Ischemia reperfusion resulted in marked renal damage with significant changes in serum and urine parameters along with marked oxidative stress and histological changes in kidneys. Pioglitazone treatment afforded anti-oxidant effect and renoprotection in a dose-dependent manner in rats. Pioglitazone-mediated renoprotection was attenuated by glutamic acid and spermidine pretreatment in rats, which indicated the role of NMDA receptors in pioglitazone-mediated protection. It is concluded that NMDA antagonism serves as one of the mechanisms in pioglitazone-mediated protection against renal IRI in rats.

Peroxisome proliferator-activated receptor-γ agonist pioglitazone fails to attenuate renal fibrosis caused by unilateral ureteral obstruction in mice

Renal tubulointerstitial fibrosis is the common ending of progressive renal disease. It is worth developing new ways to stop the progress of renal fibrosis. Peroxisome proliferator-activated receptor-γ (PPARγ) agonists have been studied to treat diabetic nephropathy, cisplatin-induced acute renal injury, ischemia reperfusion injury and adriamycin nephropathy. In this study, unilateral ureteral obstruction (UUO) was used to establish a different renal fibrosis model. PPAR? agonist pioglitazone was administrated by oral gavage and saline was used as control. At 7th and 14th day after the operation, mice were sacrificed for fibrosis test and T lymphocytes subsets test. Unexpectedly, through MASSON staining, immunohistochemistry for α-SMA, and Western blotting for a-SMA and PDGFR-β, we found that pioglitazone failed to attenuate renal fibrosis in UUO mice. However, flow cytometry showed that pioglitazone down-regulated Th1 cells, and up-regulated Th2 cells, Th17 cells and Treg cells. But the Th17/Treg ratio had no significant change by pioglitazone. Real-time PCR results showed that TGF-β and MCP-1 had no significant changes, at the same time, CD4(+) T cells associated cytokines were partially regulated by pioglitazone pretreatment. Taken together, pioglitazone failed to suppress renal fibrosis progression caused by UUO.

The peroxisome proliferator-activated receptor γ agonist pioglitazone prevents NF-κB activation in cisplatin nephrotoxicity through the reduction of p65 acetylation via the AMPK-SIRT1/p300 pathway

The thiazolidinedione pioglitazone, which is also a PPAR-γ agonist, now is widely used in patients with hypercholesterolemia and hypertriglyceridemia. NF-κB is a ubiquitously expressed transcription factor controlling the expression of numerous genes involved in inflammation. The aim of the present study was to evaluate whether the activation of PPAR-γ attenuates the cisplatin-induced NF-κB activation in cisplatin nephrotoxicity. The results showed that the PPAR-γ agonist pioglitazone decreased the expression of NF-κB p65 transcription target genes (e.g., IL-6, IL-1β, and TNF-α) and inhibited histological injury and inflammatory cells infiltration in cisplatin nephrotoxicity. The suppression of NF-κB activity following pioglitazone treatment inhibited the cisplatin-induced IκB-α degredation and NF-κB p65 subunit translocation. Translocation of the NF-κB p65 subunit depends on p65 acetylation, which primarily regulated by SIRT1 or p300. Notably, AMP kinase (AMPK) activation not only decreased the phosphorylation, activation and p65 interaction of p300 but also increased SIRT1 expression, activation and p65 binding, thus leading to a significant reduction in p65 acetylation. Interestingly, the reduction of IL-6, TNF-α and IL-1β, the inhibition of histological injury and the inflammatory cells infiltration following pioglitazone treatment in cisplatin nephrotoxicity were attenuated after treatment with the PPAR-γ antagonist GW9662. These results suggest that the PPAR-γ agonist pioglitazone prevents NF-κB activation in cisplatin nephrotoxicity through a reduction in p65 acetylation via the AMPK-SIRT1/p300 pathway.

Additive Renoprotection by Pioglitazone and Fenofibrate against Inflammatory, Oxidative and Apoptotic Manifestations of Cisplatin Nephrotoxicity: Modulation by PPARs

Nephrotoxicity is a major side effect for the antineoplastic drug cisplatin. Here, we employed pharmacological, biochemical, and molecular studies to investigate the role of peroxisome proliferator-activated receptors (PPARs) in cisplatin nephrotoxicity. Rats were treated with a single i.p. dose of cisplatin (5 mg/kg) alone or combined with pioglitazone (PPARγ agonist), fenofibrate (PPARα agonist), pioglitazone plus fenofibrate, or thalidomide (Tumor necrosis factor-α inhibitor; TNF-α). Cisplatin nephrotoxicity was evidenced by rises in renal indices of functional (blood urea nitrogen, BUN, and creatinine), inflammatory (TNF-α, interleukin 6, IL-6), oxidative (increased malondialdehyde, MDA, and decreased superoxide dismutase, SOD and nitric oxide metabolites, NOx), apoptotic (caspase 3), and histological (glomerular atrophy, acute tubular necrosis and vacuolation) profiles. Cisplatin effects were partly abolished upon concurrent exposure to pioglitazone, fenofibrate, or thalidomide; more renoprotection was observed in rats treated with pioglitazaone plus fenofibrate. Immunostaining showed that renal expressions of PPARα and PPARγ were reduced by cisplatin and restored to vehicle-treated values after simultaneous treatment with pioglitazone or fenofibrate. Fenofibrate or pioglitazone renoprotection remained unaltered after concurrent blockade of PPARα (GW6471) and PPARγ (GW9662), respectively. To complement the rat studies, we also report that in human embryonic kidney cells (HEK293 cells), increases caused by cisplatin in inflammatory, apoptotic, and oxidative biomarkers were (i) partly improved after exposure to pioglitazone, fenofibrate, or thalidomide, and (ii) completely disappeared in cells treated with a combination of all three drugs. These data establish that the combined use of pioglitazone and fenofibrate additively improved manifestations of cisplatin nephrotoxicity through perhaps GW6471/GW9662-insensitive mechanisms.

Pioglitazone Inhibits the Expressions of p22(phox) and p47(phox) in Rat Mesangial Cells In Vitro

Aim. The purpose of this study was to investigate the effects of pioglitazone on oxidative stress and the expressions of p22(phox) and p47(phox), subunits of NADPH oxidase, in mesangial cells (MCs). Method. Rat mesangial cells were cultured and randomly divided into normal glucose (NG) group, high glucose (HG) group, and pioglitazone group. After 48 h exposure, the supernatants and cells were collected. The expressions of p22(phox) and p47(phox) in MCs were detected by RT-PCR and western blot. The levels of intracellular ROS were determined by flow cytometry. Coloimetry method was used to detect malondialdehyde (MDA) concentrations and superoxide dismutase (SOD) activities. Results. Compared with the NG group, the expression levels of p22(phox), p47(phox) and ROS significantly increased, the activity of SOD decreased in HG group, while the concentration of MDA greatly increased (P < 0.01). Pioglitazone significantly suppressed HG-induced p22(phox) and p47(phox) expressions and oxidative stress. The protein and gene expressions of p22(phox) and p47(phox) were markedly reduced after pioglitazone treatment, so did the ROS generation. The activities of SOD in MCs increased, while the concentrations of MDA in the supernatant decreased greatly by pioglitazone. Conclusions. Pioglitazone can inhibit HG-induced oxidative stress in MCs through suppressing p22(phox) and p47(phox) expressions.