Renal cell apoptosis induced by nephrotoxic drugs: cellular and molecular mechanisms and potential approaches to modulation

Lysosomal membrane stabilization by imipramine attenuates gentamicin-induced renal injury: Enhanced LAMP2 expression, down-regulation of cytoplasmic cathepsin D and tBid/cytochrome c/cleaved caspase-3 apoptotic signaling

Nephrotoxicity is a serious complication commonly encountered with gentamicin (GTM) treatment. Permeabilization of lysosomes with subsequent cytoplasmic release of GTM and cathepsins is considered a crucial issue in progression of GTM toxicity. This study was designed to evaluate the prospective defensive effect of lysosomal membrane stabilization by imipramine (IMP) against GTM nephrotoxicity in rats. GTM (30 mg/kg/h) was intraperitoneally administered over 4 h daily (120 mg/kg/day) for 7 days. IMP (30 mg/kg/day) was orally administered for 14 days; starting 7 days before and then concurrently with GTM. On 15th day, samples (urine, blood, kidney) were collected to estimate biomarkers of kidney function, lysosomal stability, apoptosis, and inflammation. IMP administration to GTM-treated rats ameliorated the disruption in lysosomal membrane stability induced by GTM. That was evidenced by enhanced renal protein expressions of LAMP2 and PI3K, but reduced cathepsin D cytoplasmic expression in kidney sections. Besides, IMP guarded against apoptosis in GTM-treated rats by down-regulation of the pro-apoptotic (tBid, Bax, cytochrome c) and the effector cleaved caspase-3 expressions, while the anti-apoptotic Bcl-2 expression was enhanced. Additionally, the inflammatory cascade p38 MAPK/NF-κB/TNF-α was attenuated in GTM + IMP group along with marked improvement in kidney function biomarkers, compared to GTM group. These findings were supported by the obvious improvement in histological architecture. Furthermore, in vitro enhancement of the antibacterial activity of GTM by IMP confers an additional benefit to their combination. Conclusively, lysosomal membrane stabilization by IMP with subsequent suppression of tBid/cytochrome c/cleaved caspase-3 apoptotic signaling could be a promising protective strategy against GTM nephrotoxicity.

Investigation the effects of 2-aminoethoxydiphenyl borate (2-APB) on aminoglycoside nephrotoxicity

Investigation the protective effect of transient receptor potential channel modulator 2-Aminoethoxydiphenyl Borate (2-APB) on aminoglycoside nephrotoxicity caused by reactive oxygen species, calcium-induced apoptosis and inflammation was aimed. Forty Wistar rats were divided (n=8) as follows: Control group; DMSO group; 2-APB group; Gentamicin group (injected 100 mg/kg gentamicin intramuscularly for 10 days); Gentamicin+ 2-APB group (injected 2 mg/kg 2-APB intraperitoneally, then after 30 minutes 100 mg/kg gentamicin was injected intramuscularly for 10 days). Blood samples were collected for biochemical analyses, kidney tissue samples were collected for light, electron microscopic and immunohistochemical investigations. In gentamicin group glomerular degeneration, tubular dilatation, vacuolization, desquamation of tubular cells and hyaline cast formation in luminal space and leukocyte infiltration were seen. Disorganization of microvilli of tubular cells, apical cytoplasmic blebbing, lipid accumulation, myelin figure like structure formation, increased lysosomes, mitochondrial swelling and disorganization of cristae structures, apoptotic changes and widening of intercellular space were found. TNF-α, IL-6 and caspase 3 expressions were increased. BUN and creatinine concentrations were increased. Increase in MDA levels and decrease in SOD activities were determined. Even though degeneration still continues in gentamicin+2-APB treatment group, severity and the area it occupied were decreased and the glomerular and tubule structures were generally preserved. TNF-α, IL-6, caspase 3 immunoreactivities and BUN, creatinine, MDA concentrations were reduced and SOD activities were increased markedly compared to gentamicin group. In conclusion, it has been considered that 2-APB can prevent gentamicin mediated nephrotoxicity with its anti-oxidant, anti-apoptotic and anti-inflammatory effects.

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.

The underlying mechanisms of cisplatin-induced nephrotoxicity and its therapeutic intervention using natural compounds

Cisplatin is an effective chemotherapeutic drug widely used for the treatment of various solid tumors; however, its clinical use and efficacy are limited by its inherent nephrotoxicity. The pathogenesis of cisplatin-induced nephrotoxicity is complex and has not been fully elucidated. Cellular uptake and transport, DNA damage, apoptosis, oxidative stress, inflammatory response, and autophagy are involved in the development of cisplatin-induced nephrotoxicity. Currently, despite some deficiencies, hydration regimens remain the major protective measures against cisplatin-induced nephrotoxicity. Therefore, effective drugs must be explored and developed to prevent and treat cisplatin-induced kidney injury. In recent years, many natural compounds with high efficiency and low toxicity have been identified for the treatment of cisplatin-induced nephrotoxicity, including quercetin, saikosaponin D, berberine, resveratrol, and curcumin. These natural agents have multiple targets, multiple effects, and low drug resistance; therefore, they can be safely used as a supplementary regimen or combination therapy for cisplatin-induced nephrotoxicity. This review aimed to comprehensively describe the molecular mechanisms underlying cisplatin-induced nephrotoxicity and summarize natural kidney-protecting compounds to provide new ideas for the development of better therapeutic agents.

Synthesis of Gentamicins C1, C2, and C2a and Antiribosomal and Antibacterial Activity of Gentamicins B1, C1, C1a, C2, C2a, C2b, and X2

Complementing our earlier syntheses of the gentamicins B1, C1a, C2b, and X2, we describe the synthesis of gentamicins C1, C2, and C2a characterized by methyl substitution at the 6'-position, and so present an alternative access to previous chromatographic methods for accessing these sought-after compounds. We describe the antiribosomal activity of our full set of synthetic gentamicin congeners against bacterial ribosomes and hybrid ribosomes carrying the decoding A site of the human mitochondrial, A1555G mutant mitochondrial, and cytoplasmic ribosomes and establish structure-activity relationships with the substitution pattern around ring I to antiribosomal activity, antibacterial resistance due to the presence of aminoglycoside acetyl transferases acting on the 6'-position in ring I, and literature cochlear toxicity data.

Androgen receptor blockade by flutamide down-regulates renal fibrosis, inflammation, and apoptosis pathways in male rats

AIM

this study aims to explore the effect of androgen receptor (AR) blockade by flutamide on some renal pathologic changes such as inflammation, apoptosis, and fibrosis in male rats.

MAIN METHODS

Firstly, we investigated the potential effect of AR blockade on renal inflammatory intermediates including IL-1β, IL-6, TNF-α, NF-Қβ proteins, and the renal gene expression of NF-Қβ. Besides inflammation, we also assessed the apoptosis pathways including the caspases 3 & 9, mTOR, pAKT proteins, and BAX gene expression. Besides inflammation and apoptosis pathways, we also investigated the effect of androgen blockade on renal fibrosis intermediates including vimentin, TGFβ-1, α-SMA, MMP-9, collagen type-III, collagen type-IV, and the renal expression of the col1A1 gene. Besides previous pathological pathways, we assessed the expression of chloride channel protein-5 (ClC-5), as an important regulator of many renal pathological changes. Finally, we assessed the impact of previous pathological changes on renal function at biochemical and pathological levels.

KEY FINDINGS

We found that AR blockade by flutamide was associated with the down-regulation of renal inflammation, apoptosis, and fibrosis markers. It was associated with expression down-regulation of IL-1β & IL-6, TNF-α, NF-Қβ, caspases 3 & 9, mTOR, MMP-9, collagens, TGFβ-1, and α-SMA. Away from down-regulation, we also found that AR blockade has upregulated ClC-5 and pAKT proteins.

SIGNIFICANCE

AR is a major player in androgens-induced nephrotoxicity. AR blockade downregulates renal fibrosis, inflammation, and apoptosis pathways. It may be helpful as a strategy for alleviation of renal side effects associated with some drugs. However; this needs further investigations.

Comparative study between effects of ginkgo biloba extract and extract loaded on gold nanoparticles on hepatotoxicity induced by potassium bromate

In human organs, potassium bromate (KBrO3) produces toxicity. The main causes of KBrO3 hepatotoxicity are the formation of reactive oxygen species (ROS) and DNA damage. The purpose of this study is to show how ginkgo biloba extract (GBE) and extract loaded with nanogold particles (GBE@AuNPs) affect hepatotoxicity caused by KBrO3. The rats were separated into eight groups: control (group I), GBE (group II), AuNPs (group III), GBE@AuNPs (group IV), KBrO3 (group V), KBrO3 and GBE (group VI), KBrO3 and AuNPS (group VII), and KBrO3 and GBE@AuNPs (group VIII). KBrO3 generated DNA damage spots in a comet assay, which were associated with increased inflammatory indicators (IL-6), decreased anti-apoptotic Bcl-2, and increased apoptotic markers (Bax and caspase-3). The inflammatory, apoptotic, and ultrastructural alterations in liver tissue produced by KBrO3 were reduced in treated groups VI, VII, or VIII. The hepatotoxic effects of KBrO3 were reduced when GBE, AuNPs, or GBE@AuNPs were used; the particular GBE@AuNPs were the most effective.

Diosmin Mitigates Gentamicin-Induced Nephrotoxicity in Rats: Insights on miR-21 and -155 Expression, Nrf2/HO-1 and p38-MAPK/NF-κB Pathways

Gentamicin (GNT) is the most frequently used aminoglycoside. However, its therapeutic efficacy is limited due to nephrotoxicity. Thus, the potential anticipatory effect of Diosmin (DIOS) against GNT-prompted kidney damage in rats together with the putative nephroprotective pathways were scrutinized. Four groups of rats were used: (1) control; (2) GNT only; (3) GNT plus DIOS; and (4) DIOS only. Nephrotoxicity was elucidated, and the microRNA-21 (miR-21) and microRNA-155 (miR-155) expression and Nrf2/HO-1 and p38-MAPK/NF-κB pathways were assessed. GNT provoked an upsurge in the relative kidney weight and serum level of urea, creatinine, and KIM-1. The MDA level was markedly boosted, with a decline in the level of TAC, SOD, HO-1, and Nrf2 expression in the renal tissue. Additionally, GNT exhibited a notable amplification in TNF-α, IL-1β, NF-κB p65, and p38-MAPK kidney levels. Moreover, caspase-3 and BAX expression were elevated, whereas the Bcl-2 level was reduced. Furthermore, GNT resulted in the down-regulation of miR-21 expression along with an up-regulation of the miR-155 expression. Histological examination revealed inflammation, degradation, and necrosis. GNT-provoked pathological abnormalities were reversed by DIOS treatment, which restored normal kidney architecture. Hence, regulating miR-21 and -155 expression and modulating Nrf2/HO-1 and p38-MAPK/NF-κB pathways could take a vital part in mediating the reno-protective effect of DIOS.

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.

Biochemical interaction of pyrvinium in gentamicin-induced acute kidney injury by modulating calcium dyshomeostasis and mitochondrial dysfunction

Acute kidney injury (AKI) has a poor clinical prognosis and increases the risk of chronic kidney failure (CKD). It is a common complication of organ failure in hospitalised patients (10-15% of all hospitalizations) and in intensive care unit (ICU) patients, with an incidence of up to 50%. Concerning ICU, AKI has a mortality rate ranging from 27% to 35%, rising to 60%-65% when dialysis is needed, with roughly 5%-20% of survivors requiring dialysis on discharge. AKI is believed to cause over 7 million deaths per year worldwide. Currently, there is no treatment for AKI or its progression to CKD. When activated by AKI, numerous pathways have been suggested as possible contributors to CKD progression. Wnt/β-catenin is a crucial regulator of kidney development that increases following the injury. Despite the overwhelming evidence that Wnt/β-catenin promotes AKI, tubulointerstitial fibrosis, a hallmark of CKD progression, is also promoted by this pathway. The therapeutic potential of Wnt/β-catenin in the treatment of AKI and the progression from AKI to CKD is being studied. This hypothesis aims to determine whether the Wnt/β-catenin inhibitor pyrvinium has a beneficial effect on the renal dysfunction and damage caused by Gentamicin.

Mode of Action and Human Relevance Assessment of Male CD-1 Mouse Renal Adenocarcinoma Associated With Lifetime Exposure to Empagliflozin

Inhibition of sodium-glucose cotransporter-2 (SGLT2) has been shown to be a safe and efficacious approach to support managing Type 2 diabetes. In the 2-year carcinogenicity study with the SGLT2 inhibitor empagliflozin in CD-1 mice, an increased incidence of renal tubular adenomas and carcinomas was identified in the male high-dose group but was not observed in female mice. An integrated review of available nonclinical data was conducted to establish a mode-of-action hypothesis for male mouse-specific tumorigenesis. Five key events were identified through systematic analysis to form the proposed mode-of-action: (1) Background kidney pathology in CD-1 mice sensitizes the strain to (2) pharmacology-related diuretic effects associated with SGLT2 inhibition. (3) In male mice, metabolic demand increases with the formation of a sex- and species-specific empagliflozin metabolite. These features converge to (4) deplete oxidative stress handling reserve, driving (5) constitutive cellular proliferation in male CD-1 mice. The proposed mode of action requires all five key events for empagliflozin to present a carcinogenicity risk in the CD-1 mouse. Considering that empagliflozin is not genotoxic in the standard battery of genotoxicity tests, and not all five key events are present in the context of female mice, rats or humans, nor for other osmotic diuretics or other SGLT2 inhibitors, the observed male mouse renal tumors are not considered relevant to humans.

Advances in pediatric acute kidney injury

The objective of this study was to inform the pediatric nephrologists of recent advances in acute kidney injury (AKI) epidemiology, pathophysiology, novel biomarkers, diagnostic tools, and management modalities. Studies were identified from PubMed, EMBASE, and Google Scholar for topics relevant to AKI. The bibliographies of relevant studies were also reviewed for potential articles. Pediatric (0-18 years) articles from 2000 to May 2020 in the English language were included. For epidemiological outcomes analysis, a meta-analysis on data regarding AKI incidence, mortality, and proportion of kidney replacement therapy was performed and an overall pooled estimate was calculated using the random-effects model. Other sections were created highlighting pathophysiology, novel biomarkers, changing definitions of AKI, evolving tools for AKI diagnosis, and various management modalities. AKI is a common condition seen in hospitalized children and the diagnosis and management have shown to be quite a challenge. However, new standardized definitions, advancements in diagnostic tools, and the development of novel management modalities have led to increased survival benefits in children with AKI. IMPACT: This review highlights the recent innovations in the field of AKI, especially in regard to epidemiology, pathophysiology, novel biomarkers, diagnostic tools, and management modalities.

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.

Mechanism Prediction of Astragalus membranaceus against Cisplatin-Induced Kidney Damage by Network Pharmacology and Molecular Docking

Background

Cisplatin is a frequently used and effective chemotherapy drug in clinical practice, but severe side effects limit its use, among which nephrotoxicity is considered the most serious and prolonged damage to the body. Astragalus membranaceus (AM) is a well-known herbal medicine, and modern pharmacological studies have confirmed its antioxidant, immunomodulatory, and antiapoptotic effects. Clinical studies have shown that AM and its active components can attenuate cisplatin-induced kidney damage, but the molecular mechanism has not been fully expounded.

Materials and Methods

First, the components and targets information of AM were collected from the TCMSP, and the relevant targets of cisplatin-induced kidney damage were accessed from the GeneCards and OMIM databases. Then, the core targets were selected by the Venn diagram and network topology analysis, which was followed by GO and KEGG pathway enrichment analysis. Finally, we construct a component-target-pathway network. Furthermore, molecular docking was carried out to identify the binding activity between active components and key targets.

Results

A total of 20 active components and 200 targets of AM and 646 targets related to cisplatin-induced kidney damage were obtained. 91 intersection targets were found between AM and cisplatin-induced kidney damage. Then, 16 core targets were identified, such as MAPK1, TNF-α, and p53. Furthermore, GO and KEGG pathway enrichment analysis suggested that MAPK, Toll-like receptor, and PI3K-Akt signaling pathways may be of significance in the treatment of cisplatin-induced kidney damage by AM. Molecular docking indicated that quercetin and kaempferol had high binding affinities with many core targets.

Conclusion

In summary, the active components, key targets, and signaling pathways of AM in the treatment of cisplatin-induced kidney damage were predicted in this study, which contributed to the development and application of AM.

Increased Endocytosis of Cadmium-Metallothionein through the 24p3 Receptor in an In Vivo Model with Reduced Proximal Tubular Activity

BACKGROUND

The proximal tubule (PT) is the major target of cadmium (Cd2+) nephrotoxicity. Current dogma postulates that Cd2+ complexed to metallothionein (MT) (CdMT) is taken up through receptor-mediated endocytosis (RME) via the PT receptor megalin:cubilin, which is the predominant pathway for reuptake of filtered proteins in the kidney. Nevertheless, there is evidence that the distal parts of the nephron are also sensitive to damage induced by Cd2+. In rodent kidneys, another receptor for protein endocytosis, the 24p3 receptor (24p3R), is exclusively expressed in the apical membranes of distal tubules (DT) and collecting ducts (CD). Cell culture studies have demonstrated that RME and toxicity of CdMT and other (metal ion)-protein complexes in DT and CD cells is mediated by 24p3R. In this study, we evaluated the uptake of labeled CdMT complex through 24p3R after acute kidney injury (AKI) induced by gentamicin (GM) administration that disrupts PT function. Subcutaneous administration of GM at 10 mg/kg/day for seven days did not alter the structural and functional integrity of the kidney's filtration barrier. However, because of PT injury, the concentration of the renal biomarker Kim-1 increased. When CdMT complex coupled to FITC was administered intravenously, both uptake of the CdMT complex and 24p3R expression in DT increased and also colocalized after PT injury induced by GM. Although megalin decreased in PT after GM administration, urinary protein excretion was not changed, which suggests that the increased levels of 24p3R in the distal nephron could be acting as a compensatory mechanism for protein uptake. Altogether, these results suggest that PT damage increases the uptake of the CdMT complex through 24p3R in DT (and possibly CD) and compensate for protein losses associated with AKI.

An Integrated Transcriptomic Approach to Identify Molecular Markers of Calcineurin Inhibitor Nephrotoxicity in Pediatric Kidney Transplant Recipients

Calcineurin inhibitors are highly efficacious immunosuppressive agents used in pediatric kidney transplantation. However, calcineurin inhibitor nephrotoxicity (CNIT) has been associated with the development of chronic renal allograft dysfunction and decreased graft survival. This study evaluated 37 formalin-fixed paraffin-embedded biopsies from pediatric kidney transplant recipients using gene expression profiling. Normal allograft samples (n = 12) served as negative controls and were compared to biopsies exhibiting CNIT (n = 11). The remaining samples served as positive controls to validate CNIT marker specificity and were characterized by other common causes of graft failure such as acute rejection (n = 7) and interstitial fibrosis/tubular atrophy (n = 7). MiRNA profiles served as the platform for data integration. Oxidative phosphorylation and mitochondrial dysfunction were the top molecular pathways associated with overexpressed genes in CNIT samples. Decreased ATP synthesis was identified as a significant biological function in CNIT, while key toxicology pathways included NRF2-mediated oxidative stress response and increased permeability transition of mitochondria. An integrative analysis demonstrated a panel of 13 significant miRNAs and their 33 CNIT-specific gene targets involved with mitochondrial activity and function. We also identified a candidate panel of miRNAs/genes, which may serve as future molecular markers for CNIT diagnosis as well as potential therapeutic targets.

Kidney physiology and susceptibility to acute kidney injury: implications for renoprotection

Kidney damage varies according to the primary insult. Different aetiologies of acute kidney injury (AKI), including kidney ischaemia, exposure to nephrotoxins, dehydration or sepsis, are associated with characteristic patterns of damage and changes in gene expression, which can provide insight into the mechanisms that lead to persistent structural and functional damage. Early morphological alterations are driven by a delicate balance between energy demand and oxygen supply, which varies considerably in different regions of the kidney. The functional heterogeneity of the various nephron segments is reflected in their use of different metabolic pathways. AKI is often linked to defects in kidney oxygen supply, and some nephron segments might not be able to shift to anaerobic metabolism under low oxygen conditions or might have remarkably low basal oxygen levels, which enhances their vulnerability to damage. Here, we discuss why specific kidney regions are at particular risk of injury and how this information might help to delineate novel routes for mitigating injury and avoiding permanent damage. We suggest that the physiological heterogeneity of the kidney should be taken into account when exploring novel renoprotective strategies, such as improvement of kidney tissue oxygenation, stimulation of hypoxia signalling pathways and modulation of cellular energy metabolism.

A nanosensor for precise discrimination of nephrotoxic drug mechanisms via dynamic fluorescence fingerprint strategy

Drug-induced kidney injury causes structural or functional abnormalities of kidney, seriously affecting clinical practice and drug discovery. However, rapid and effective identification of nephrotoxic drug mechanisms is yet a challenging task arising from the complexity and diversity of various nephrotoxic mechanisms. Herein, we have constructed a polydopamine-polyethyleneimine/quantum dots sensor to instantaneously read out the nephrotoxic drugs mechanisms based on the disparate cell surface phenotypes. Cell surface components induced by multiple nephrotoxic drugs can change the fluorescence emission of multicolor quantum dots, generating their corresponding fluorescent fingerprints. The fluorescence response signatures induced by different nephrotoxic agents are gained with 84% accuracy via linear discriminant analysis. Furthermore, taking the time-toxicity relationship into consideration, dynamic fluorescent fingerprint is obtained through continuous monitoring the progress of renal cell damage, achieving 100% precise classification for nephrotoxic mechanisms of four types of antibiotics. Notably, the fluorescent fingerprint-based high-throughput sensor has been demonstrated by successfully distinguishing nephrotoxic drugs in seconds, employing a promising protocol to discriminate the specific mechanism of nephrotoxic drugs, as well as drug safety evaluation.

Dehydroxymethylepoxyquinomicin, a novel nuclear factor-κB inhibitor, prevents the development of cyclosporine A nephrotoxicity in a rat model

Background

Cyclosporine A (CsA) is an essential immunosuppressant in organ transplantation. However, its chronic nephrotoxicity is an obstacle to long allograft survival that has not been overcome. Nuclear factor-κB (NF-κB) is activated in the renal tissue in CsA nephropathy. In this study, we aimed to investigate the effect of the specific NF-κB inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ), in a rat model of CsA nephrotoxicity.

Methods

We administered CsA (15 mg/kg) daily for 28 days to Sprague-Dawley rats that underwent 5/6 nephrectomy under a low-salt diet. We administered DHMEQ (8 mg/kg) simultaneously with CsA to the treatment group, daily for 28 days and evaluated its effect on CsA nephrotoxicity.

Results

DHMEQ significantly inhibited NF-κB activation and nuclear translocation due to CsA treatment. Elevated serum urea nitrogen and creatinine levels due to repeated CsA administration were significantly decreased by DHMEQ treatment (serum urea nitrogen in CsA + DHMEQ vs CsA vs control, 69 ± 6.4 vs 113.5 ± 8.8 vs 43.1 ± 1.1 mg/dL, respectively, p < 0.0001; serum creatinine in CsA + DHMEQ vs CsA vs control, 0.75 ± 0.02 vs 0.91 ± 0.02 vs 0.49 ± 0.02 mg/dL, respectively, p < 0.0001), and creatinine clearance was restored in the treatment group (CsA + DHMEQ vs CsA vs control, 2.57 ± 0.09 vs 1.94 ± 0.12 vs 4.61 ± 0.18 ml/min/kg, respectively, p < 0.0001). However, DHMEQ treatment did not alter the inhibitory effect of CsA on urinary protein secretion. The development of renal fibrosis due to chronic CsA nephrotoxicity was significantly inhibited by DHMEQ treatment (CsA + DHMEQ vs CsA vs control, 13.4 ± 7.1 vs 35.6 ± 18.4 vs 9.4 ± 5.4%, respectively, p < 0.0001), and these results reflected the results of renal functional assessment. DHMEQ treatment also had an inhibitory effect on the increased expression of chemokines, monocyte chemoattractant protein-1, and chemokine (c-c motif) ligand 5 due to repeated CsA administration, which inhibited the infiltration of macrophages and neutrophils into the renal tissue.

Conclusions

These findings suggest that DHMEQ treatment in combination therapy with CsA-based immunosuppression is beneficial to prevent the development of CsA-induced nephrotoxicity.

Renal Sympathetic Nerve-Derived Signaling in Acute and Chronic kidney Diseases

The kidney is innervated by afferent sensory and efferent sympathetic nerve fibers. Norepinephrine (NE) is the primary neurotransmitter for post-ganglionic sympathetic adrenergic nerves, and its signaling, regulated through adrenergic receptors (AR), modulates renal function and pathophysiology under disease conditions. Renal sympathetic overactivity and increased NE level are commonly seen in chronic kidney disease (CKD) and are critical factors in the progression of renal disease. Blockade of sympathetic nerve-derived signaling by renal denervation or AR blockade in clinical and experimental studies demonstrates that renal nerves and its downstream signaling contribute to progression of acute kidney injury (AKI) to CKD and fibrogenesis. This review summarizes our current knowledge of the role of renal sympathetic nerve and adrenergic receptors in AKI, AKI to CKD transition and CKDand provides new insights into the therapeutic potential of intervening in its signaling pathways.

Molecular nephrology: types of acute tubular injury

The acute loss of kidney function has been diagnosed for many decades using the serum concentration of creatinine - a muscle metabolite that is an insensitive and non-specific marker of kidney function, but is now used for the very definition of acute kidney injury (AKI). Fortunately, myriad new tools have now been developed to better understand the relationship between acute tubular injury and elevation in serum creatinine (SCr). These tools include unbiased gene and protein expression analyses in kidney, urine and blood, the localization of specific gene transcripts in pathological biopsy samples by rapid in-situ RNA technology and single-cell RNA-sequencing analyses. However, this molecular approach to AKI has produced a series of unexpected problems, because the expression of specific kidney-derived molecules that are indicative of injury often do not correlate with SCr levels. This discrepancy between kidney injury markers and SCr level can be reconciled by the recognition that many separate subtypes of AKI exist, each with distinct patterning of molecular markers of tubular injury and SCr data. In this Review, we describe the weaknesses of isolated SCr-based diagnoses, the clinical and molecular subtyping of acute tubular injury, and the role of non-invasive biomarkers in clinical phenotyping. We propose a conceptual model that synthesizes molecular and physiological data along a time course spanning from acute cellular injury to organ failure.

Tacrolimus: 20 years of use in adult kidney transplantation. What we should know about its nephrotoxicity

Tacrolimus (or FK506), a calcineurin inhibitor (CNI) introduced in field of transplantation in the 1990s, is the cornerstone of most immunosuppressive regimens in solid organ transplantation. Its use has revolutionized the future of kidney transplantation (KT) and has been associated with better graft survival, a lower incidence of rejection, and improved drug tolerance with fewer side effects compared to cyclosporine. However, its monitoring remains complicated and underexposure increases the risk of rejection, whereas overexposure increases the risk of adverse effects, primarily nephrotoxicity, neurotoxicity, infections, malignancies, diabetes, and gastrointestinal complaints. Tacrolimus nephrotoxicity can be nonreversible and can lead to kidney graft loss, and its diagnosis is therefore best made with reference to the clinical context and after exclusion of other causes of graft dysfunction. Many factors contribute to its development including: systemic levels of tacrolimus; local renal exposure to tacrolimus; exposure to metabolites of tacrolimus; local susceptibility factors for CNI nephrotoxicity independent of systemic or local tacrolimus levels, such as the age of a kidney; local renal P-glycoprotein, local intestinal and hepatic cytochrome P450A3, and renin angiotensin system activation. The aim of this review is to describe the pharmacokinetics, pharmacodynamics, and mechanisms of acute and chronic tacrolimus nephrotoxicity in adult KT.

Nephrotoxicity and Renal Pathophysiology: A Contemporary Perspective

The kidney consists of numerous cell types organized into the nephron, which is the basic functional unit of the kidney. Any stimuli that induce loss of these cells can induce kidney damage and renal failure. The cause of renal failure can be intrinsic or extrinsic. Extrinsic causes include cardiovascular disease, obesity, diabetes, sepsis, and lung and liver failure. Intrinsic causes include glomerular nephritis, polycystic kidney disease, renal fibrosis, tubular cell death, and stones. The kidney plays a prominent role in mediating the toxicity of numerous drugs, environmental pollutants and natural substances. Drugs known to be nephrotoxic include several cancer therapeutics, drugs of abuse, antibiotics, and radiocontrast agents. Environmental pollutants known to target the kidney include cadmium, mercury, arsenic, lead, trichloroethylene, bromate, brominated-flame retardants, diglycolic acid, and ethylene glycol. Natural nephrotoxicants include aristolochic acids and mycotoxins such as ochratoxin, fumonisin B1, and citrinin. There are several common characteristics between mechanisms of renal failure induced by nephrotoxicants and extrinsic causes. This common ground exists primarily due to similarities in the molecular mechanisms mediating renal cell death. This review summarizes the current state of the field of nephrotoxicity. It emphasizes integrating our understanding of nephrotoxicity with pathological-induced renal failure. Such approaches are needed to address major questions in the field, which include the diagnosis, prognosis and treatment of both acute and chronic renal failure, and the progression of acute kidney injury to chronic kidney disease.

Cell Death in the Kidney

Apoptotic cell death is usually a response to the cell’s microenvironment. In the kidney, apoptosis contributes to parenchymal cell loss in the course of acute and chronic renal injury, but does not trigger an inflammatory response. What distinguishes necrosis from apoptosis is the rupture of the plasma membrane, so necrotic cell death is accompanied by the release of unprocessed intracellular content, including cellular organelles, which are highly immunogenic proteins. The relative contribution of apoptosis and necrosis to injury varies, depending on the severity of the insult. Regulated cell death may result from immunologically silent apoptosis or from immunogenic necrosis. Recent advances have enhanced the most revolutionary concept of regulated necrosis. Several modalities of regulated necrosis have been described, such as necroptosis, ferroptosis, pyroptosis, and mitochondrial permeability transition-dependent regulated necrosis. We review the different modalities of apoptosis, necrosis, and regulated necrosis in kidney injury, focusing particularly on evidence implicating cell death in ectopic renal calcification. We also review the evidence for the role of cell death in kidney injury, which may pave the way for new therapeutic opportunities.

Melittin Inducing the Apoptosis of Renal Tubule Epithelial Cells through Upregulation of Bax/Bcl-2 Expression and Activation of TNF-α Signaling Pathway

Background

Acute kidney injury (AKI) caused by bee stings is common, with characteristics of acute onset, severe illness, and high mortality. Melittin, a major component of bee venom, has been considered to play a key role in bee sting related AKI. This study aims to illustrate whether melittin could lead to apoptosis of renal tubular epithelial cells (RTECs) and to investigate its mechanism.

Methods

In vivo, 45 mice were randomly divided into the melittin group (n=30, injected with melittin into the tail vein according to the total dose of 4.0 ug/g weight) and the control group (n=15, injected with the same volume of saline into the tail vein). In vitro, human RTECs (HK-2) were cultured and treated with melittin (2ug/ml or 4ug/ml) and TNF-α (10ng/ml). Biochemical analysis, HE stains, and electron microscope were performed to evaluate renal function and pathological changes. TUNEL stains and flow cytometry were performed to detect apoptosis. Real-time PCR was performed to detect mRNA levels of Bax, Bcl-2, and TNF-α. Simple western assay and immunohistochemical (IH) and immunofluorescent (IF) stains were performed for protein detection.

Results

Melittin successfully induced AKI in mice. Compared with the control group, obvious injury and apoptosis of RTECs were observed in the melittin group; the mRNA and protein expressions of Bax were significantly increased, while the expression of Bcl-2 was significantly decreased. The serum TNF-αlevel in melittin group was significantly higher than that in control group. In vitro, the results confirmed that melittin can cause HK-2 cells apoptosis. The trends of expression of Bax and Bcl-2 were consistent with the results in vivo. The levels of TNF-α mRNA and protein by PCR and Western blot were significantly higher in melittin group than those in control group.

Conclusion

Melittin can lead to the apoptosis of RTECs, which may be mediated by upregulating the expression of Bax/Bcl-2 and activating the TNF-α signaling pathway.

Has vitamin E any shreds of evidence in cisplatin-induced toxicity

Cisplatin is one of the highly consumed and effective antitumor agents whose clinical application is accompanied by nephrotoxicity adverse reaction. Also, other complications such as ototoxicity and hepatotoxicity are a matter of concern. Today, it is suggested that cisplatin-associated toxicities are mainly induced by free radicals production, which will result in oxidative organ injury. The evidence is growing over the protective effects of antioxidants on cisplatin-induced adverse reactions especially nephrotoxicity. The possible protective effects of vitamin E and its derivative in cisplatin-induced nephrotoxicity and ototoxicity are reviewed here at the light of pertinent results from basic and clinical research. Administration of vitamin E alone or in combination with other antioxidant agents could cause amelioration in oxidative stress biomarkers such as decreasing the level of malondialdehyde, reducing serum urea and creatinine, and also enhancing the activities of renal antioxidant enzymes including renal catalase, glutathione-S-transferase, and superoxide dismutase. Although the data from most of the studies are in favors of protective effects of vitamin E against cisplatin-induced toxicity, more clinical trials are needed to clarify the clinical importance of vitamin E administration as an antioxidant during cisplatin therapy in cancer condition.

Potential protective effects of Dapagliflozin in gentamicin induced nephrotoxicity rat model via modulation of apoptosis associated miRNAs

BACKGROUND

Drug-induced kidney injury (DIKI) can be manifested with progressive chronic kidney diseases or end-stage renal diseases. Understanding the molecular disarrangements caused by DIKI is an attractive point of interest. A class of non-coding RNA called microRNAs (miRNAs) is known to play a major role in regulation of gene expression and signaling pathways making miRNAs excellent targets for new therapeutic agents.

AIM OF THE STUDY

We aimed to investigate the role of miRNA 21 and 181a in gentamicin (GNT) induced nephrotoxicity rat model and the protective effect of Dapagliflozin (DAPA) in modulating their expression through studying its effect on renal function as well as renal histopathological changes.

MATERIALS AND METHODS

Wistar rats were used and divided into: naïve, DAPA, GNT and DAPA + GNT groups. In all studied groups, kidney function, oxidative stress, apoptosis markers and miRNAs' expression in serum and renal biopsies were investigated in addition to the histopathological studies to identify its early renoprotective effect.

RESULTS

DAPA was found to improve kidney function, oxidative stress markers, decrease apoptosis of renal tubular cells and increase miR-21 but decrease the expression of miR-181a with restoration of the renal architecture after 14 days of treatment in GNT induced nephrotoxicity rat model.

CONCLUSIONS

DAPA produced significant decrease in renal expression of miR-181a on the other hand it increased the expression of renal miR-21, this may introduce a novel early protective effect of DAPA against GNT-induced nephrotoxicity.

Dietary Radix Bupleuri extracts improves hepatic lipid accumulation and immune response of hybrid grouper (Epinephelus lanceolatus♂ × Epinephelus fuscoguttatus♀)

In this study, two experiments were performed to explore the effect of Radix Bupleuri extracts (RBE) on growth, lipid deposition and metabolism and immune response of hybrid grouper (Epinephelus lanceolatus♂ × Epinephelus fuscoguttatus♀) using in vitro and in vivo models. In vitro, we used 2 ml/L 20% lipid emulsion (LE)-induced steatosis in hybrid grouper primary hepatocytes, then RBE (200, 400 and 800 μg/ml) was added to the hepatocytes after (post-treatment) the incubation with 20% LE (2 ml/L) in the culture medium. We found that RBE markedly increased cell viability, which were consistent with hepatocytes morphological structure examination and lipid metabolism and immune related genes study. The above result suggested that RBE has a protective effect on this model of hepatocytes damage. In vivo, five graded levels of RBE at 0, 200, 400, 800 and 1600 mg/kg diet were supplemented to a basal diet with 15% lipid levels (high lipid), and fed to a total of 300 hybrid grouper with an average initial weight of 25.58 ± 0.05 g for 8 weeks. Growth performance, liver histology, plasma biochemical parameters, and expression of genes involved in lipid metabolism and immune-related were measured. The study indicated that dietary RBE significantly improved growth performance and feed utilization and reduced hepatosomatic index. Dietary supplementation with 200-800 mg/kg RBE diets effectively decreased serum ALP, ALT, AST and LDH contents in fish. Furthermore, adipogenesis relative mRNA levels of DGAT2, G6PD, ME1 and DGKα in fish fed 200-400 mg/kg RBE diets were lower (P < 0.05) than in those fed RBE0 diets, while dietary supplementation with 200-800 mg/kg RBE diets up-regulated lipolysis-related genes (CPT1, LPL and PPARα) expression in the liver of hybrid grouper. Moreover, dietary RBE down-regulated the expression of apoptosis-related genes (caspase-9), up-regulated the expression of antioxidant genes (CAT) and immune-related genes (MHC2, IKKα and TGF-β1). Thus, our data suggest that RBE suppressed lipid accumulation and enhanced immune capability in hybrid grouper both in vitro and in vivo. These results offer new insight into RBE as a hepatoprotective in fish.

Wuzhi capsule regulates chloroacetaldehyde pharmacokinetics behaviour and alleviates high-dose cyclophosphamide-induced nephrotoxicity and neurotoxicity in rats

High-dose cyclophosphamide (HD-CTX) treatment often leads to severe nephrotoxicity and neurotoxicity, which are mainly caused by one of its metabolites, chloroacetaldehyde (CAA). However, there are no effective antidotes to prevent these side effects. The objective of this study was to evaluate the effect of Wuzhi Capsule (WZC) on the pharmacokinetics of CTX and its metabolites in rats, and the attenuation of CAA induced kidney and brain injuries, which was produced at equimolar with 2-dechloroethylcyclophosphamide. Rats were treated with single- or multiple-dose of WZC when giving HD-CTX, and the plasma concentration of CTX and its metabolites were quantitated by UHPLC-MS/MS Single-dose, not multiple-dose of WZC co-administration (300 mg/kg) significantly reduced C_max and AUC_0→24 h of DC-CTX by 33.10% and 35.51%, respectively. Biochemical assay suggested oxidative stress was involved in kidney and brain injuries by HD-CTX, which were attenuated by single-dose WZC (300 mg/kg) pre-treatment, with increased glutathione, glutathione peroxidase and superoxide dismutase contents/or activities in both tissues and plasma (P < 0.05). Meanwhile, WZC pre-treatment could also significantly decrease the plasma levels of creatinine, blood urea nitrogen and malondialdehyde (P < 0.05). Additionally, WZC treatment improved the morphology and pathology condition of the kidneys and brains in rats. In conclusion, single-dose WZC co-administration decreased CAA production and exerted protective effect on CTX-induced oxidative stress in kidney and brain, whereas repetitive WZC co-administration with CTX was probably not recommended.

Multiple Targets of 3-Dehydroxyceanothetric Acid 2-Methyl Ester to Protect Against Cisplatin-Induced Cytotoxicity in Kidney Epithelial LLC-PK1 Cells

Chronic exposure to cisplatin, a potent anticancer drug, causes irreversible kidney damage. In this study, we investigated the protective effect and mechanism of nine lupane- and ceanothane-type triterpenoids isolated from jujube (Ziziphus jujuba Mill., Rhamnaceae) on cisplatin-induced damage to kidney epithelial LLC-PK1 cells via mitogen-activated protein kinase (MAPK) and apoptosis pathways. Cisplatin-induced LLC-PK1 cell death was most significantly reduced following treatment with 3-dehydroxyceanothetric acid 2-methyl ester (3DC2ME). Additionally, apoptotic cell death was significantly reduced. Expression of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38 was markedly suppressed by 3DC2ME, indicating inhibition of the MAPK pathway. Treatment with 3DC2ME also significantly reduced expression of active caspase-8 and -3, Bcl-2-associated X protein (Bax), and B cell lymphoma 2 (Bcl-2), indicating the inhibition of apoptosis pathways in the kidneys. We also applied the network pharmacological analysis and identified multiple targets of 3DC2ME related to MAPK signaling pathway and apoptosis.

The Protective Effect of Fluorofenidone against Cyclosporine A-Induced Nephrotoxicity

BACKGROUND/AIMS

Cyclosporine A (CsA) is an immunosuppressant drug that is used during organ transplants. However, its utility is limited by its nephrotoxic potential. This study aimed to investigate whether fluorofenidone (AKF-PD) could provide protection against CsA-induced nephrotoxicity.

METHODS

Eighty-five male Sprague-Dawley rats were divided into 5 groups: drug solvent, CsA, CsA with AKF-PD (250, 500 mg/kg/day), and CsA with pirfenidone (PFD, 250 mg/kg/day). Tubulointerstitial injury index, extracellular matrix (ECM) deposition, expression of type I and IV collagen, transforming growth factor (TGF)-β1, platelet-derived growth factor (PDGF), Fas ligand (FASL), cleaved-caspase-3, cleaved-poly(ADP-ribose) polymerase (PARP)-1, and the number of transferase-mediated nick end-labeling (TUNEL)-positive renal tubule cells were determined. In addition, levels of TGF-β1, FASL, cleaved-caspase-3, cleaved-PARP-1, and number of annexin V-positive cells were determined in rat proximal tubular epithelial cells (NRK-52E) treated with CsA (20 μmol/L), AKF-PD (400 μg/mL), PFD (400 μg/mL), and GW788388 (5 μmol/L).

RESULTS

AKF-PD (250, 500 mg/kg/day) significantly reduced tubulointerstitial injury, ECM deposition, expression of type I and IV collagen, TGF-β1, PDGF, FASL, cleaved-caspase-3, cleaved-PARP-1, and number of TUNEL-positive renal tubule cells in the CsA-treated kidneys. In addition, AKF-PD (400 μg/mL) significantly decreased TGF-β1, FASL, cleaved-caspase-3, and PARP-1 expression in NRK-52E cells and further reduced the number of annexin V-positive cells.

CONCLUSION

AKF-PD protect kidney from fibrosis and apoptosis in CsA-induced kidney injury.

Microglial Calcium Release-Activated Calcium Channel Inhibition Improves Outcome from Experimental Traumatic Brain Injury and Microglia-Induced Neuronal Death

Store-operated Ca²⁺ entry (SOCE) mediated by calcium release-activated calcium (CRAC) channels contributes to calcium signaling. The resulting intracellular calcium increases activate calcineurin, which in turn activates immune transcription factor nuclear factor of activated T cells (NFAT). Microglia contain CRAC channels, but little is known whether these channels play a role in acute brain insults. We studied a novel CRAC channel inhibitor to explore the therapeutic potential of this compound in microglia-mediated injury. Cultured microglial BV2 cells were activated by Toll-like receptor agonists or IFNγ. Some cultures were treated with a novel CRAC channel inhibitor (CM-EX-137). Western blots revealed the presence of CRAC channel proteins STIM1 and Orai1 in BV2 cells. CM-EX-137 decreased nitric oxide (NO) release and inducible nitric oxide synthase (iNOS) expression in activated microglia and reduced agonist-induced intracellular calcium accumulation in microglia, while suppressing inflammatory transcription factors nuclear factor kappa B (NF-κB) and nuclear factor of activated T cells (NFAT). Male C57/BL6 mice exposed to experimental brain trauma and treated with CM-EX-137 had decreased lesion size, brain hemorrhage, and improved neurological deficits with decreased microglial activation, iNOS and Orai1 and STIM1 levels. We suggest a novel anti-inflammatory approach for managing acute brain injury. Our observations also shed light on new calcium signaling pathways not described previously in brain injury models.

Mitochondrial pathway of apoptosis and necrosis contribute to tenofovir disoproxil fumarate-induced renal damage in rats

Tenofovir disoproxil fumarate (TDF) is currently the only nucleotide analogue reverse-transcriptase inhibitor that is approved by the Food and Drug administration (FDA), USA, for the treatment of human immunodeficiency virus (HIV) infection. In recent days, renal toxicity is becoming common i HIV patients treated with TDF. However, the mechanism of tenofovir nephrotoxicity is not clear. We hypothesized that mitochondrial pathway of apoptosis, poly [ADP-ribose] polymerase (PARP) overactivation and neutrophil infiltration may contribute to tenofovir-induced renal damage. Renal damage was induced in adult male Wistar rats by the oral administration of 600 mg/kg body weight daily for five consecutive weeks. Kidneys were removed and used for histological and biochemical analyses. Apoptosis was detected by terminal deoxynucleotidyl transferase biotin-deoxyuridine triphosphate nick end-labelling (TUNEL) assay and caspase 3 activity and protein expression; mitochondrial pathway of apoptosis by cyt c release; and PARP activation by immunofluorescence, immunohistochemistry and Western blot techniques. Myeloperoxidase (MPO) activity was measured as a marker of neutrophil infiltration. TDF administration resulted in increased number of TUNEL-positive cells, activation of caspase 3 and release of cyt c from mitochondria into the cytosol in the kidneys. There was increased nuclear localization of PARP as well as increase in its protein level in the TDF-treated rat kidneys. In addition, renal MPO activity was increased ninefold as compared to controls. The results of the present study show that mitochondrial apoptotic pathway, PARP overactivation and neutrophil infiltration contribute to tenofovir-induced renal damage in rats.

The protective effects of selenium-enriched Spirulina platensis on chronic alcohol-induced liver injury in mice

The aim of this study was to investigate the protective effect and mechanism of selenium-enriched Spirulina platensis (S. platensis) on chronic alcohol-induced liver injury. Selenium incubation raises the nutrition quality of S. platensis by absorption enhancement of functional elements. Our results demonstrated that the effective dose of selenium-enriched S. platensis on HL7702 cells treated with alcohol was 200 μg ml-1, containing 20% selenium. Selenium-enriched S. platensis could raise the cell survival rate by decreasing the expression of p53, Caspase3, LC3, and Caspase1 and by increasing the expression of p70s6k. In vivo experiments, where mice were pretreated with selenium-enriched S. platensis, exhibited obvious inhibition of the liver function index and this pretreatment enhanced the activity of GSH-Px and SOD in alcohol induced mice. In summary, our results indicate that the protective mechanism of selenium-enriched S. platensis on chronic alcoholic liver injury is associated with the activity enhancement of antioxidant enzymes and immunity, the inhibition of DNA damage and apoptosis, accompanied with autophagy and pyroptosis.

Potential protective effects of naringenin against vancomycin-induced nephrotoxicity via reduction on apoptotic and oxidative stress markers in rats

Vancomycin (VCM), a glycopeptide antibiotic, is a drug widely used in severe infections. However, VCM induce notable nephrotoxic side effects. Naringenin (NAR) is a natural of flavonoid and are known as strongly antioxidant, nefroprotective, antiapoptotic, and anti-inflammatory. The purpose of this study was to determine the potential protective effects of NAR against VCM-induced nephrotoxicity by measuring apoptotic and oxidative stress markers and evaluating histopathological alterations in rats. For this purpose, we used male Wistar albino rats that divided into seven groups: (i) Control [saline, intraperitoneally (i.p.)], (ii) carboxymethyl cellulose (0.5% CMC, orally), (iii) VCM (400 mg/kg, i.p.), (iv) NAR100 (100 mg/kg, orally), (v) VCM + NAR25 (25 mg/kg, orally), (vi) VCM + NAR50 (50 mg/kg, orally), and (vii) VCM + NAR100 (100 mg/kg, orally) groups. VCM administration was started one day after the first treatment of NAR and continued across 7-day. Caspase-3, -8, and-9 activities and malondialdehyde (MDA) and nitric oxide (NO) levels were measured by colorimetric methods in the kidney tissues, creatinine, and blood urea nitrogen (BUN) levels were analyzed based on ELISA in serum. Caspase-3 and -8 activities, NO levels, serum creatinine and BUN levels were significantly higher in VCM group in comparison with VCM + NAR (25, 50, and 100) groups (p < 0.05). Caspase-9 activity and MDA were significantly higher in VCM group compared to VCM + NAR (25 and 50) groups (p < 0.05). Histopathological alterations in VCM group were significantly diminished by administration of NAR, especially NAR 25. In conclusion, NAR 25 and 50 mg have more potent protective effects on VCM-induced nephrotoxicity compared to NAR 100 mg.

Beneficial Effects of Bioactive Compounds in Mulberry Fruits against Cisplatin-Induced Nephrotoxicity

Mulberry, the fruit of white mulberry tree (Morus alba L., Moraceae), is commonly used in traditional Chinese medicines as a sedative, tonic, laxative, and emetic. In our continuing research of the bioactive metabolites from mulberry, chemical analysis of the fruits led to the isolation of five compounds, 1–5. The compounds were identified as butyl pyroglutamate (1), quercetin 3-O-β-d-glucoside (2), kaempferol 3-O-β-d-rutinoside (3), rutin (4), and 2-phenylethyl d-rutinoside (5) by spectroscopic data analysis, comparing their nuclear magnetic resonance (NMR) data with those in published literature, and liquid chromatography–mass spectrometry analysis. The isolated compounds 1–5 were evaluated for their effects on anticancer drug-induced side effects by cell-based assays. Compound 1 exerted the highest protective effect against cisplatin-induced kidney cell damage. This effect was found to be mediated through the attenuation of phosphorylation of c-Jun N-terminal kinase, extracellular signal-regulated kinase, p38, mitogen-activated protein kinase, and caspase-3 in cisplatin-induced kidney cell damage.

Tetrahydrocurcumin Ameliorates Tacrolimus-Induced Nephrotoxicity Via Inhibiting Apoptosis

BACKGROUND

Calcineurin inhibitors are effective immunosuppressive agents, but associated adverse effects such as nephrotoxicity may limit efficacy. Tacrolimus (FK506) is an immunosuppressive drug used mainly to lower the risk of organ rejection after allogeneic organ transplant. Adverse effects of FK-506 can prompt patients to end treatment despite the efficacy. In the present study, we investigated the protective effect and mechanism of tetrahydrocurcumin (THC) on FK506-induced renal damage, apoptosis, and oxidative stress to evaluate its possible use for kidney protection.

MATERIALS AND METHODS

The effect of THC on FK506-induced kidney cell damage was investigated in LLC-PK1 cells. LLC-PK1 cells were pretreated with THC at concentrations of dose for 2 hours followed by addition of FK506 for 24 hours. LLC-PK1 cells were treated with FK506 and THC, and cell viability and glutathione was measured. The number of apoptotic cells was measured using an annexin V/propidium iodide staining with flow cytometry. The effect of apoptosis by THC in LLC-PK1 cells was determined by measuring the caspase-9, caspase-3, B-cell lymphoma-2 (Bcl-2), and Bcl-2-associated X protein levels using Western blotting analyses.

RESULTS

FK506-induced LLC-PK1 renal cell damage was markedly ameliorated by THC treatment. THC protected LLC-PK1 cells by preventing FK506-induced glutathione decrease. THC protects against FK506-induced apoptosis in LLC-PK1 cells. Apoptosis was significantly decreased, and Bcl-2 was elevated in the THC-treated group. Bcl-2-associated X protein, caspase-3, and caspase-9 were decreased in the THC-treated group.

CONCLUSION

These results collectively provide therapeutic evidence that THC ameliorates the FK506-induced renal damage via antioxidant effect and apoptosis inhibition.

Cyclosporin A inhibits mitochondrial biogenesis in Hep G2 cells

Dysregulation of mitochondrial biogenesis is associated with pathogenesis in many diseases, including liver diseases. Cyclosporine A (CsA), one of the most commonly used drug to treat many autoimmune diseases and to prevent allograft rejection after organ transplantation, has been reported to cause mitochondrial dysfunction. However, the cellular mechanisms underlying CsA on mitochondrial dysfunction remain at present not completely elucidated. In this study, we found that CsA reduced the expression of PGC-1α at both the mRNA and protein levels in HepG2 cells. Correspondingly, the expressions of its target genes NRF 1 and TFAM were reduced in response to CsA treatment. In addition, mtDNA/nDNA, mitochondria mass, ATP production, and cytochrome C oxidase activity were significantly reduced by treatment with CsA. Over-expression of PGC-1α was found to rescue the negative effect of CsA administration on mitochondrial biogenesis. Mechanistically, CREB was involved in the inhibitory effects of CsA in mitochondrial biogenesis.

Dietary butylated hydroxytoluene improves lipid metabolism, antioxidant and anti-apoptotic response of largemouth bass (Micropterus salmoides)

A 10-week growth trail was conducted to investigate the efficacy and tolerance of dietary butylated hydroxytoluene (BHT) by evaluating inflammation, apoptosis and hepatic disease related to oxidative stress in largemouth bass (Micropterus salmoides). Four experimental diets were prepared with BHT supplement levels of 0 (B0), 150 (B150), 300 (B300) and 1500 (B1500) mg/kg, in which B150 was at the maximum recommended level established by European Union Regulation, and the B300 and B1500 levels were 2 and 10-fold of B150, respectively. Each diet was fed to 6 replicates with 30 largemouth bass (initial body weight, IBW = 6.20 ± 0.01 g) in each tank. The BHT inclusion level did not affect the specific growth rate, but fish in the B150 group showed the lowest feed conversion rate (P < 0.05). BHT inclusion significantly decreased the levels of plasma TC, TG, LDL, ALT and AKP, and increased the (HDL-C)/TC ratio (P < 0.05). Plasma MDA was significantly decreased in the B150 group and GSH-Px was extremely enhanced in each BHT inclusion group (P < 0.05). Hepatic T-AOC was significantly enhanced and O₂^- was significantly decreased in each BHT inclusion group compared to the B0 group (P < 0.05), as well as hepatic MDA was significantly decreased in B1500 group (P < 0.05). Dietary BHT inclusion down-regulated the hepatic mRNA levels of inflammation, apoptosis and fibrosis related genes, including TNFα, TGF-β1, α-SMA, IL8, IL11β and caspase-9. Moreover, BHT could improve hepatic lipid metabolism via up-regulating the mRNA levels of APOA1, CYP7A1, CYP8B1, and down-regulating the mRNA levels of PPAR-γ and APOB. Histological examination of the liver morphology with H&E and Sirius Red staining showed that BHT inclusion decreased necrotic degenerative changes and collagen deposition in largemouth bass. An immunofluorescence examination revealed significantly decreased cleaved caspase-3 signals in the BHT groups. In conclusion, the results demonstrated that ROS induces hepatic cell apoptosis and fibrosis via the intrinsic pathway of apoptosis by activating caspase-9 in the mitochondria and then initiates apoptosis by activating caspase-3. Consuming 2.32-23.80 mg/kg·bw/d (150-1500 mg/kg in diet) of BHT effectively improved the plasma and hepatic lipid metabolism, antioxidant response as well as reduced ROS production, protecting hepatic cells from injury. It is implied that even a 10-fold increase of the maximum level of BHT (150 mg/kg) is safe for the largemouth bass.

Sinapic acid modulates Nrf2/HO-1 signaling pathway in cisplatin-induced nephrotoxicity in rats

BACKGROUND

Cisplatin-induced nephrotoxicity is related to increased reactive oxygen species and inflammatory cytokines in the kidney. Sinapic acid (SA) has both antioxidant and anti-inflammatory activities.

AIMS

We determined the effects of SA on cisplatin-induced nephrotoxicity in rats, and the potential mechanisms by which it augments antioxidant responses and attenuates nephrotoxicity related to oxidative/nitrosative stress, apoptosis, and inflammation.

METHODS

Kidney function markers (i.e., serum urea, uric acid, creatinine, and lactate dehydrogenase), oxidative stress markers (i.e., lipid peroxidation and nitric oxide), antioxidant systems (i.e., superoxide dismutase, catalase, and reduced glutathione), inflammation markers (i.e., tumor necrosis factor-α [TNF-α], interleukin-6 [IL-6], and myeloperoxidase [MPO]), apoptotic markers (caspase 3, Bax, and Bcl-2), and the levels of nuclear factor-κB (NF-κB [p65]), Nrf2, and heme oxygenase-1 (HO-1) were assessed. Histopathological examinations of the kidney were also used to evaluate cisplatin-induced nephrotoxicity.

KEY FINDINGS

SA (10 and 20mg/kg) pretreatment ameliorated kidney function, upregulated antioxidant levels, and downregulated lipid peroxidation and nitric oxide levels in cisplatin-injected rats, resulting in significant reductions in oxidative stress and replenishment of endogenous antioxidant enzymes. Cisplatin upregulated cytokines (i.e., TNF-α and IL-6) and MPO, increased apoptosis, and downregulated Nrf2 and HO-1. SA pretreatment downregulated the pro-apoptotic caspase-3 and Bax proteins, and upregulated the anti-apoptotic Bcl-2 protein. SA pretreatment also alleviated the extent of histological impairment and reduced neutrophil infiltration in renal tubules.

SIGNIFICANCE

The results suggest that the Nrf2/HO-1 signaling pathway may be the primary target for protection from cisplatin-induced nephrotoxicity by SA, and that SA reduces oxidative stress, inflammation, and apoptosis by inhibiting NF-κB.

Early postnatal gentamicin and ceftazidime treatment in normal and food restricted neonatal wistar rats: Implications for kidney development

BACKGROUND

Up to two-thirds of premature born neonates are treated for infections with aminoglycosides such as gentamicin. Although acute toxicities are well described, there is uncertainty on developmental changes after treatment of premature born neonates. We studied the effect of gentamicin and ceftazidime on kidney development in the rat. Additionally, we evaluated the modulating effect of extrauterine growth restriction.

METHODS

On postnatal day (PND) 2, Wistar rats were cross-fostered into normal sized litters (12 pups) or large litters (20 pups) to create normal food (NF) or food restricted (FR) litters to simulate growth restriction and dosed daily intraperitoneally with placebo, 4 mg/kg of gentamicin or 50 mg/kg ceftazidime until PND 8. Gentamicin pharmacokinetics were studied in a separate group of animals. Kidneys were weighed. Renal expression of 18 developmental genes was evaluated by quantitative PCR on PND 8. On PND 35, glomerular number was assessed by stereology and glomerular generations were counted.

RESULTS

Food restricted litters showed 22% less body weight compared with controls by day 35 (p < 0.001), 1.4- to 1.5-fold down regulation of Renin, Oat1, and Agtr1a (p < 0.05) expression and a 12% reduction in glomerular numbers (mean 30841 vs. 35187, p < 0.001), whereas glomerular generation count was unaffected. Gentamicin pharmacokinetic parameters were found to be in a human clinical range (mean maximum concentration in plasma of 4.88 mg/L and mean area under the plasma-concentration time curve up to the last measured concentration after 4 hr of 10.71 mg.h/L for sexes combined) and all endpoints were unaffected. Ceftazidime reduced Renin expression by 1.7-fold (p < 0.01).

CONCLUSION

Our experiments showed that gentamicin at clinical levels did not disturb kidney development, ceftazidime can affect Renin expression, and extrauterine growth restriction impairs kidney development, but did not modulate potential drug toxicity. Birth Defects Research 109:1228-1235, 2017. © 2017 Wiley Periodicals, Inc.

Selenium nanoparticles with low-level ionizing radiation exposure ameliorate nicotine-induced inflammatory impairment in rat kidney

Occupational exposure to low-level ionizing radiation (<1 Gy) was shown to enhance cell protection via attenuating an established inflammatory process. Nicotine, a major toxic component of cigarette smoke, is responsible for smoking-mediated renal dysfunction. The present study was therefore aimed to investigate the protective impact of ginger Zingiber officinale selenium nanoparticles (SeNPs) with whole-body low-dose gamma radiation (γ-R) against nicotine-induced nephrotoxicity in male albino rats. Nicotine intoxication was induced with 0.5 mg/kg BW. Rats received 0.1 mg SeNPs/kg BW by gastric gavage concomitant with 0.5 Gy γ-R over 4 weeks. Characterization studies showed the formation of spherical SeNPs with a size ranged from 10 to 30 nm in diameter with a thin film encapsulating the nanoballs. Our data revealed that nicotine induced renal dysfunction manifested by significant abnormal levels of kidney function markers (creatinine, urea, sodium and potassium) accompanied by increased levels of malondialdehyde along with a reduction in glutathione level, glutathione peroxidase, and glutathione S-transferase activities. It is worthy to note that nicotine toxicity induced significant increments in serum inflammatory markers: tumor necrosis factor-α and vascular cell adhesion protein 1. Western blotting showed marked significant elevation in caspase-3 activities against nicotine. The mRNA gene expression of inducible cyclooxygenase-2 gene was highly increased with nicotine intoxication while that of cyclooxygenase-1 did not show any changes. Interestingly, our data demonstrated that SeNPs in synergistic interaction with γ-R are efficacious control against nicotine-induced nephrotoxicity via anti-oxidant-mediated anti-inflammatory activities. Thus, it is tempting to recommend dietary approaches with ginger SeNPs for smokers at workplaces exposed occupationally and regularly to low-level ionizing radiation.

Effect of Lycopene and Rosmarinic Acid on Gentamicin Induced Renal Cortical Oxidative Stress, Apoptosis, and Autophagy in Adult Male Albino Rat

Gentamicin nephrotoxicity accounts for 10%-15% of all cases of acute renal failure. Several natural antioxidants were found to be effective against drug-induced toxicity. The possible protective effects of lycopene (Lyc) and rosmarinic acid (RA) alone or combined on gentamicin (Gen) induced renal cortical oxidative stress, apoptosis, and autophagy were evaluated. Sixty-three rats were randomly divided into seven groups named: control, group II received RA 50 mg/kg/day, group III received Lyc 4 mg/kg/day, group IV received Gen 100 mg/kg/day, group V (RA + Gen), group VI (Lyc + Gen), and group VII (RA + Lyc + Gen). At the end of the experiment, kidney functions were estimated then the kidneys were sampled for histopathological, immunohistochemistry, and biochemical studies. Administration of rosmarinic acid and lycopene decreased elevated serum creatinine, blood urea nitrogen, renal malondialdehyde and immunoexpression of the proapoptotic protein (Bax), autophagic marker protein (LC3/B), and inducible nitric oxide synthase (iNOS) induced by gentamicin. They increased reduced glutathione, glutathione peroxidase, superoxide dismutase, and immunoexpression of the antiapoptotic protein (Bcl2). They also improved the histopathological changes induced by gentamicin. The combination therapy of rosmarinic acid and lycopene shows better protective effects than the corresponding monotherapy. Anat Rec, 300:1137-1149, 2017. © 2016 Wiley Periodicals, Inc.

Gentamicin nephrotoxicity in animals: Current knowledge and future perspectives

Due to high relative blood flow the kidney is prone to drug-induced damage. Aminoglycoside type antibiotic gentamicin is one of the leading cause of drug-induced nephrotoxicity. In recent years gentamicin nephrotoxicity is significantly reduced by shifting to once daily dosage as well as by eliminating known risk factors. Application of gentamicin is still related to serious side effects which are reported more often compared to other antibiotics. Because gentamicin is still heavily used and is highly efficient in treating infections, it is important to find mechanisms to reduce its nephrotoxicity. This aim can only be achieved through better understanding of kidney metabolism of gentamicin. This problem has been extensively researched in the last 20 years. The experimental results have provided evidence for almost complete understanding of mechanisms responsible for gentamicin nephrotoxicity. We now have well described morphological, biochemical and functional changes in kidney due to gentamicin application. During the years, this model has become so popular that now it is used as an experimental model for nephrotoxicity per se. This situation can mislead an ordinary reader of scientific literature that we know everything about it and there is nothing new to discover here. But quite opposite is true. The precise and complete mechanism of gentamicin nephrotoxicity is still point of speculation and an unfinished story. With emerge of new and versatile technics in biomedicine we have an opportunity to reexamine old beliefs and discover new facts. This review focuses on current knowledge in this area and gives some future perspectives.

Optimising the use of medicines to reduce acute kidney injury in children and babies

The majority of medications in children are administered in an unlicensed or off-label manner. Paediatricians are obliged to prescribe using the limited evidence available. The 2007 EU regulation on the use of paediatric drugs means pharmaceutical companies are now obliged to (and receive incentives for) contributing to paediatric drug data and carrying out paediatric clinical trials. This is important, as the efficacy and adverse effect profiles of medicines vary across childhood. Additionally, there are significant age-related changes in the pharmacodynamic and pharmacokinetic activity of many drugs. This may be related to physiological (differential expressions of cytochrome P450 enzymes or variable glomerular filtration rates at different ages for example) and psychological (increasing autonomy and risk perception in teenage years) changes. Increasing numbers of children are surviving life-threatening childhood conditions due to medical advances. This means there is an increasing population who are at risk of the consequences of the long-term, early exposure to nephrotoxic agents. The kidney is an organ that is particularly vulnerable to damage as a consequence of drugs. Drug-induced acute kidney injury (AKI) episodes in children and babies are principally due to non-steroidal anti-inflammatory drugs, antibiotics or chemotherapeutic agents. The renal tubules are vulnerable to injury because of their concentrating ability and high-energy hypoxic environment. This review focuses on drug-induced AKI and the methods to minimise its effect, including general management plus the role of child-specific pharmacokinetic data, the use of pharmacogenomics and early detection of AKI using urinary biomarkers and electronic triggers.

Protective effect of ginsenoside Rb1 against tacrolimus-induced apoptosis in renal proximal tubular LLC-PK1 cells

Background

The aim of the present study was to evaluate the potential protective effects of six ginsenosides (Rb1, Rb2, Rc, Rd, Rg1, and Rg3) isolated from Panax ginseng against tacrolimus (FK506)-induced apoptosis in renal proximal tubular LLC-PK1 cells.

Methods

LLC-PK1 cells were treated with FK506 and ginsenosides, and cell viability was measured. Protein expressions of mitogen-activated protein kinases, caspase-3, and kidney injury molecule-1 (KIM-1) were evaluated by Western blotting analyses. The number of apoptotic cells was measured using an image-based cytometric assay.

Results

Reduction in cell viability by 60μM FK506 was ameliorated significantly by cotreatment with ginsenosides Rg1 and Rb1. The phosphorylation of p38, extracellular signal-regulated kinases, and KIM-1, and cleavage of caspase-3, increased markedly in LLC-PK1 cells treated with FK506 and significantly decreased after cotreatment with ginsenoside Rb1. The number of apoptotic cells decreased by 6.0% after cotreatment with ginsenoside Rb1 (10μM and 50μM).

Conclusion

The antiapoptotic effects of ginsenoside Rb1 on FK506-induced apoptosis were mediated by the inhibition of mitogen-activated protein kinases and caspase activation.