Intermittent exposure to xenon protects against gentamicin-induced nephrotoxicity

Therapy Targeted to the NLRP3 Inflammasome in Chronic Kidney Disease

Background

The NLRP3 inflammasome is a cytoplasmic polymeric protein complex composed of the cytoplasmic sensor NLRP3, the apoptosis-related spot-like protein ASC, and the inflammatory protease caspase-1. NLRP3 activates and releases IL-1β through classical pathways, and IL-18 mediates inflammation and activates gasdermin-D protein to induce cellular pyroptosis. Numerous studies have also emphasized the non-classical pathway activated by the NLRP3 inflammasome in chronic kidney disease (CKD) and the inflammasome-independent function of NLRP3.

Summary

The NLRP3-targeting inflammasome and its associated pathways have thus been widely studied in models of CKD treatment, but no drug that targets NLRP3 has thus far been approved for the treatment of CKD.

Key Messages

We herein reviewed the current interventional methods for targeting the NLRP3 inflammasome in various CKD models, analyzed their underlying mechanisms of action, classified and compared them, and discussed the advantages and follow-up directions of various interventional methods. This review therefore provides novel ideas and a reference for the development of targeted NLRP3-inflammasome therapy in CKD.

Effect of xenon and argon inhalation on erythropoiesis and steroidogenesis: A systematic review

Background

Xenon and argon inhalation were included on the WADA Prohibited List in 2014 due to the reported positive effects on erythropoiesis and steroidogenesis that occur as a result of their application. Thus, the systematic review of studies supporting these notions is of interest.

Methods

A thorough search on the effects of xenon and argon inhalation on erythropoiesis and steroidogenesis, as well as their negative effects on human health and method detection was conducted. Pubmed and Google Scholar databases and the Cochrane Library were researched, as well as the WADA research section. The search was conducted in accordance with the PRISMA guidelines. All articles written in English and published between 2000 and 2021 were analyzed, as well as reference studies meeting the search criteria.

Results

At present, there are only two publications in healthy human subjects evaluating the effects of xenon inhalation on erythropoiesis that found no conclusive evidence of a positive effect on erythropoiesis. This research was published following the inclusion of this gas on the WADA Prohibited List in 2014 and had a high risk of bias. There were no studies available on the effect of argon inhalation on erythropoiesis. Furthermore, no studies were found on the effect of xenon or argon inhalation on steroidogenesis in healthy subjects and no studies relating to the effects of xenon or argon inhalation on erythropoiesis and steroidogenesis were found on the WADA website.

Conclusion

There is still inconclusive evidence to support the administration of xenon and argon inhalations on erythropoiesis and steroidogenesis and their positive effects on health. Further research is warranted to establish the effects of these gases. Additionally, improved communication between anti-doping authorities and all key stakeholders is required to support the inclusion of various substances on recognized prohibited lists.

Low-intensity pulsed ultrasound (LIPUS) switched macrophage into M2 phenotype and mitigated necroptosis and increased HSP 70 in gentamicin-induced nephrotoxicity

BACKGROUND AND AIM

Many attempts to control acute kidney injury (AKI) have failed due to a lack of understanding of its pathophysiological key components. Macrophages are a crucial determinant of AKI, which can be categorized functionally as M1 pro-inflammatory and M2 anti-inflammatory macrophages. Low-intensity pulsed ultrasound (LIPUS) is currently being investigated as an immune modulator. The present study aimed to explore the potential effects of LIPUS on the polarization of renal macrophages, as well as the possible interplay between macrophage polarization and necroptosis in gentamicin-induced acute kidney injury.

METHOD

All rats were randomly allocated into one of four groups: control, LIPUS-treated control, gentamicin acute kidney (GM-AKI), and LIPUS-treated GM-AKI. Renal functions, macrophage polarization, necroptosis, and heat shock protein-70 (HSP70) were analyzed using real-time reverse-transcriptase-polymerase chain reaction (rT-PCR), Western Blot, Enzyme-linked immunosorbent assay (ELISA) as well as immunohistological analysis.

RESULTS

we found that LIPUS markedly inhibited the expressions of M1 macrophage-related genes and promoted significantly the expression of M2 macrophages related genes. This was accompanied by an inhibition of necroptosis and a marked reduction of HSP-70, resulting in a reversal of gentamicin-induced renal alteration.

CONCLUSION

Functional switching of macrophage responses from M1 into M2 seems to be a potential approach to ameliorate necroptosis as well as HSP-70 by low pulsed ultrasound waves in GM-AKI.

Supplementation of carotenoids from peach palm waste (Bactris gasipaes) obtained with an ionic liquid mediated process displays kidney anti-inflammatory and antioxidant outcomes

•

Carotenoid’s supplementation can control weight gain even in the HFD model.

•

Carotenoids extracted with ionic liquids displayed antioxidant activity on the kidney.

•

Carotenoids extracted with ionic liquids display an anti-inflammatory effect.

•

Carotenoids extracted with acetone increase pro-inflammatory cytokines on the kidney.

•

Carotenoids extracted with acetone display oxidative stress on the kidney.

Sustainable extraction processes based on alternative solvents to recover bioactive compounds of different raw materials have been highlighted as excellent alternatives to supply the needs of society towards a bioeconomy strategy. Little is known about the safety and biological effect of compounds extracted by these processes. In this work, carotenoids from Bactris gasipaes wastes obtained by an IL-based process were investigated in terms of safety, anti-inflammatory and, antioxidant activity in a high-fat-diet animal model on the kidney. Wistar rats were supplemented or not by carotenoids extracted with IL or VOS. The animals supplemented with carotenoids had lower weight than control and high-fat diets. In the animals supplemented with carotenoids, the group IL improved anti-inflammatory and antioxidant activity compared with carotenoids obtained by VOS. Also, the group HFD-VOS showed moderate-severe injuries on the kidney. Then, ILs could represent a novel tool for natural pigments safely applied to food industry.

A Mitocentric View of the Main Bacterial and Parasitic Infectious Diseases in the Pediatric Population

Infectious diseases occur worldwide with great frequency in both adults and children. Both infections and their treatments trigger mitochondrial interactions at multiple levels: (i) incorporation of damaged or mutated proteins to the complexes of the electron transport chain, (ii) mitochondrial genome (depletion, deletions, and point mutations) and mitochondrial dynamics (fusion and fission), (iii) membrane potential, (iv) apoptotic regulation, (v) generation of reactive oxygen species, among others. Such alterations may result in serious adverse clinical events with great impact on children's quality of life, even resulting in death. As such, bacterial agents are frequently associated with loss of mitochondrial membrane potential and cytochrome c release, ultimately leading to mitochondrial apoptosis by activation of caspases-3 and -9. Using Rayyan QCRI software for systematic reviews, we explore the association between mitochondrial alterations and pediatric infections including (i) bacterial: M. tuberculosis, E. cloacae, P. mirabilis, E. coli, S. enterica, S. aureus, S. pneumoniae, N. meningitidis and (ii) parasitic: P. falciparum. We analyze how these pediatric infections and their treatments may lead to mitochondrial deterioration in this especially vulnerable population, with the intention of improving both the understanding of these diseases and their management in clinical practice.

Protective Effect of Grape and Apple Juices against Cadmium Intoxication in the Kidney of Rats

BACKGROUND

The objective of this study was to evaluate protective effect of grape and apple juices against toxicity induced by cadmium in the kidney of rats.

METHODS

A total of 20 male-Wistar rats were distributed into four groups (n=5): Control group: animals received an intraperitoneal (i.p.) injection of 0.9% saline solution and after 15 days, 1 mL of water was administered for 15 days, via gavage; Cadmium group: animals received an intraperitoneal injection of cadmium chloride (1.2 mg/kg) and after 15 days, 1 mL of water was administered for 15 days via gavage; Cadmium+Grape Juice: animals received an i.p. injection of cadmium chloride (1.2 mg/kg), and after 15 days, 0.8 mL of grape juice was administered for 15 days, via gavage; Cadmium+Apple Juice: animals received i.p. injection of cadmium chloride (1.2 mg/kg) and after 15 days, 1.0 mL of apple juice was administered for 15 days, via gavage.

RESULTS

Histopathological analysis revealed severe tubular lesion and necrosis in the group exposed to cadmium, while animals exposed to grape or apple juices showed a significant reduction of tissue injury. 8-OHdG immunoexpression, DNA damage, cytochrome C and catalase gene expressions and Toll like signaling pathway (TLR2, and pIKKα/β) decreased in animals treated with grape juice when compared to cadmium group.

CONCLUSION

Taken together, we conclude that grape and apple juices had a protective effect by means of antioxidant, antigenotoxic actions and for promoting tissue regeneration in the kidney of rats following cadmium intoxication.

Closed circuit xenon delivery for 72h in neonatal piglets following hypoxic insult using an ambient pressure automated control system: Development, technical evaluation and pulmonary effects

BACKGROUND

Therapeutic hypothermia (TH) for 72h is the standard treatment following neonatal encephalopathy (NE). However, one-third do not benefit and adjunctive therapies are urgently needed. Xenon enhances neuroprotection with TH when administered at 50% concentration within 5hours of hypoxia in experimental studies. Delayed initiation (~10 hours of age) of 30% xenon for 24 hours during TH did not improve early adverse biomarkers in a clinical trial of Xenon+TH vs TH. After hypoxia-ischemia, excitotoxic injury via N-methyl-D-aspartate receptor overactivation lasts days. Since xenon partially inhibits this receptor, we hypothesised that giving 50% xenon throughout the entire 72h TH and rewarming periods would enhance neuroprotection. Xenon costs $30/litre, so a closed-circuit breathing system is desirable with automated fresh gas delivery.

METHODS

Seven mechanically ventilated newborn pigs were randomized to receive 50% inhaled xenon for 72h during hypothermia (rectal-temperature 35°C) and subsequent rewarming following a global hypoxic-ischemic insult (XeHT, N = 4) or under normothermia for 72h (rectal-temperature 38.5°C) following sham insult (XeNT, N = 3). An automated fresh gas delivery system injected oxygen/air/xenon boluses into a closed-circuit based on measured gas concentrations.

RESULTS AND DISCUSSION

Median (IQR) xenon consumption was 0.31 L/h (0.18, 0.50) and 0.34L/h (0.32, 0.49) for hypothermic and normothermic groups respectively, 0.34L/h (0.25, 0.53) overall. 92% of 9626 xenon and 69% of 9635 oxygen measurements were within 20% variation from targets. For xenon concentration, the median absolute performance errors for the XeHT and XeNT groups were 6.14% and 3.84% respectively and 4.31% overall. For oxygen these values were 13.42%, 15.05% and 12.4% respectively. There were no adverse pulmonary pathophysiology findings. Clinical problems over the total period included three related to sensors, seven breathing system leaks, ten partial and one complete tracheal tube occlusion episodes.

CONCLUSION

The automated controller functioned as intended maintaining an inhaled xenon concentration close to the 50% target for 72-78h at a xenon cost of $11.1/h.

Effect of acute and chronic xenon inhalation on erythropoietin, hematological parameters, and athletic performance

This study aimed to assess the efficacy of acute subanesthetic dosages of xenon inhalation to cause erythropoiesis and determine the effect of chronic xenon dosing on hematological parameters and athletic performance. To assess the acute effects, seven subjects breathed three subanesthetic concentrations of xenon: 30% fraction of inspired xenon (FiXe) for 20 min, 50% FiXe for 5 min, and 70% FiXe for 2 min. Erythropoietin (EPO) was measured at baseline, during, and after xenon inhalation. To determine the chronic effects, eight subjects breathed 70% FiXe for 2 min on 7 consecutive days, and EPO, total blood, and plasma volume were measured. Phase II involved assessment of 12 subjects for EPO, total blood volume, maximal oxygen uptake, and 3-km time before and after random assignment to 4 wk of xenon or sham gas inhalation. FiXe 50% and 70% stimulated an increase in EPO at 6 h [+2.3 mIU/mL; 95% confidence interval (CI) 0.1–4.5; P = 0.038] and at 192 h postinhalation (+2.9 mIU/mL; 95% CI 0.6–5.1; P = 0.017), respectively. Seven consecutive days of dosing significantly elevated plasma volume (+491 mL; 95% CI 194–789; P = 0.002). Phase II showed no significant effect on EPO, hemoglobin mass, plasma volume, maximal oxygen uptake, or 3-km time. Acute exposure to subanesthetic doses of xenon caused a consistent increase in EPO, and 7 consecutive days of xenon inhalation significantly expanded plasma volume. However, this physiological response appeared to be transient, and 4 wk of xenon inhalation did not stimulate increases in plasma volume or erythropoiesis, leaving cardiorespiratory fitness and athletic performance unchanged.

NEW & NOTEWORTHY This is the first study to examine each element of the cascade by which xenon inhalation is purported to take effect, starting with measurement of the hypoxia-inducible factor effector, erythropoietin, to hemoglobin mass and blood volume and athletic performance. We found that acute exposure to xenon increased serum erythropoietin concentration, although major markers of erythropoiesis remained unchanged. While daily dosing significantly expanded plasma volume, no physiological or performance benefits were apparent following 4 wk of dosing.

METTL3/m6A/miRNA-873-5p Attenuated Oxidative Stress and Apoptosis in Colistin-Induced Kidney Injury by Modulating Keap1/Nrf2 Pathway

Nephrotoxicity of colistin is the major factor limiting its clinical application. However, the exact mechanism of colistin-induced nephrotoxicity is still elusive. N⁶-Methyladenosine (m⁶A) modification has been implicated in many biological processes, however, its role in colistin-induced nephrotoxicity needs to be elucidated. Mouse renal tubular epithelial cells (mRTECs) were treated with 200 μM colistin with or without METTL3 overexpression. Cells injury, m⁶A assay, oxidative stress and apoptosis were examined. Levels of m⁶A are decreased after colistin treatment in mRTECs. METTL3 is the major factor involved in abnormal m⁶A modification. METTL3 overexpression plays a protective role against colistin-induced oxidative stress and apoptosis. Moreover, METTL3 interacts with the microprocessor protein DGCR8 and positively modulates miR-873-5p mature process in an m⁶A-dependent manner. Further experiments show that miR-873-5p could regulate Keap1-Nrf2 pathway against colistin-induced oxidative stress and apoptosis. These studies revealed an important role of METTL3/m⁶A in colistin-induced nephrotoxicity and provide a new insight on m⁶A modification in drug induced toxicity.

Argon Mitigates Impaired Wound Healing Process and Enhances Wound Healing In Vitro and In Vivo

Diabetic foot ulcers are associated with significant morbidity and mortality, and current treatments are far from optimal. Chronic wounds in diabetes are characterised by impaired angiogenesis, leukocyte function, fibroblast proliferation, and keratinocyte migration and proliferation.

Methods: We tested the effect of exposure to argon gas on endothelial cell, fibroblast, macrophage and keratinocyte cell cultures in vitro and in vivo of a streptozotocin-induced diabetic mouse model.

Results: Exposure to normobaric argon gas promotes multiple steps of the wound healing process. Argon accelerated angiogenesis, associated with upregulation of pro-angiogenic Angiopoietin-1 and vascular endothelial growth factor (VEGF) signalling in vitro and in vivo. Treatment with argon enhanced expression of transforming growth factor (TGF)-β, early recruitment of macrophages and keratinocyte proliferation. Argon had a pro-survival effect, inducing expression of cytoprotective mediators B-cell lymphoma 2 and heme oxygenase 1. Argon was able to accelerate wound closure in a diabetic mouse model.

Conclusion: Together these findings indicate that argon gas may be a promising candidate for clinical use in treatment of diabetic ulcers.

Reno-protective effects of ursodeoxycholic acid against gentamicin-induced nephrotoxicity through modulation of NF-κB, eNOS and caspase-3 expressions

Gentamicin (GNT) is a potent aminoglycoside antibiotic widely used to treat life-threatening bacterial infections. We aim to investigate the potential protective effect of ursodeoxycholic acid (UDCA) against GNT-induced nephrotoxicity. In this study, 24 male Wistar rats were used and randomly divided into four groups of six animals each. Control group received 0.5% carboxymethyl cellulose orally for 15 days, GNT group received GNT 100 mg/kg/day i.p. for 8 days, UDCA group received UDCA orally for 15 consecutive days at a dose of 60 mg/kg/day suspended in 0.5% carboxymethyl cellulose and UDCA-pretreated group received UDCA orally for 7 days then co-administered with GNT i.p. for 8 days at the same fore-mentioned doses. Serum levels of kidney function parameters (urea, creatinine, uric acid and albumin) were measured. Renal tissues were used to evaluate oxidative stress markers; malonaldehyde (MDA), reduced glutathione (GSH) and the anti-oxidant enzyme superoxide dismutase (SOD) activities and nuclear factor kappa light-chain enhancer of activated B cells (NF-κB) and kidney injury molecule-1 (KIM-1) mRNA levels. Immunohistochemical expression of endothelial nitric oxide synthase (eNOS) and caspase-3 and histological and ultrastructural examination were performed. Treatment with GNT increased the serum levels of renal function parameters and renal MDA, NF-κB and KIM-1 mRNA levels, while it decreased GSH and SOD activities. Marked immunohistochemical expression of caspase-3 was observed after GNT administration while it decreased eNOS expression. Histological and ultrastructural alterations were also evident in renal corpuscles and tubules. In contrast, pretreatment with UDCA reversed changes caused by GNT administration. These results suggest that UDCA ameliorates GNT-induced kidney injury via inhibition of oxidative stress, inflammation and apoptosis.

Aged kidney: can we protect it? Autophagy, mitochondria and mechanisms of ischemic preconditioning

The anti-aging strategy is one of the main challenges of the modern biomedical science. The term "aging" covers organisms, cells, cellular organelles and their constituents. In general term, aging system admits the existence of nonfunctional structures which by some reasons have not been removed by a clearing system, e.g., through autophagy/mitophagy marking and destroying unwanted cells or mitochondria. This directly relates to the old kidney which normal functioning is critical for the viability of the organism. One of the main problems in biomedical studies is that in their majority, young organisms serve as a standard with further extrapolation on the aged system. However, some protective systems, which demonstrate their efficiency in young systems, lose their beneficial effect in aged organisms. It is true for ischemic preconditioning of the kidney, which is almost useless for an old kidney. The pharmacological intervention could correct the defects of the senile system provided that the complete understanding of all elements involved in aging will be achieved. We discuss critical elements which determine the difference between young and old phenotypes and give directions to prevent or cure lesions occurring in aged organs including kidney.

ABBREVIATIONS

AKI: acute kidney injury; I/R: ischemia/reperfusion; CR: caloric restriction; ROS: reactive oxygen species; RC: respiratory chain.

A systematic meta-analysis on the efficacy of pre-clinically tested nephroprotectants at preventing aminoglycoside nephrotoxicity

Nephrotoxicity limits the use of aminoglycoside antibiotics. Kidney damage is produced mainly in the renal tubule due to an inflammatory and oxidative process. At preclinical level, many drugs and natural products have been tested as prospective protectors of aminoglycoside nephrotoxicity. The main objective of this work was to make a systematic literature review of preclinical studies about aminoglycoside nephrotoxicity protection and a statistical analysis based on the meta-analysis methodology. Studies published up to January 2016 were identified. After applying inclusion criteria, 54 studies were chosen. The size of the experimental groups, means and standard deviations of data on renal function (i.e. plasma creatinine and blood urea nitrogen [BUN] concentrations) were extracted and registered in a database. The studies were grouped according to the mechanism of nephroprotection and their route of administration. The Mean Difference (95% confidence interval) was calculated for each study and group. 40 of 54 products tested produced an amelioration of aminoglycoside nephrotoxicity based on creatinine results. Also a dose dependent protective effect was observed (both in creatinine and BUN). Products orally administered were more effective than via i.p. Products with attributed antioxidant activity were the most used and those which proved statistically significant nephroprotection as a class effect. Aminoglycoside tubular reuptake inhibitors, excretion inducers and calcium channel blockers also showed a promising and rather homogeneous class tendency towards nephroprotection, although more research is necessary to obtain solid and conclusive results, based on a larger number of studies.

Pinocembrin attenuates gentamicin-induced nephrotoxicity in rats

Oxidative stress mediated apoptosis of renal tubular cells is a major pathology of gentamicin-induced nephrotoxicity, which is one of the prevailing causes of acute renal failure. Pinocembrin is a major flavonoid found in rhizomes of fingerroot (Boesenbergia pandurata). It has pharmacological and biological activities including antimicrobial, anti-inflammatory, and antioxidant effects. Preclinical studies have suggested that pinocembrin protects rat brain and heart against oxidation and apoptosis induced by ischemia–reperfusion. The aim of the current study was to investigate the mechanisms of renoprotection elicited by pinocembrin in gentamicin-induced nephrotoxicity. Nephrotoxicity was induced in rats by intraperitoneal injection (i.p.) of gentamicin, and pinocembrin was administered via i.p. 30 min before gentamicin treatment for 10 days. Gentamicin-induced nephrotoxicity was indicated by the reduced renal function and renal Oat3 function and expression. Gentamicin treatment also stimulated Nrf2, HO-1, and NQO1, as well as the pro-apoptotic proteins Bax and caspase-3, concomitant with the attenuation of Bcl-XL expression in the renal cortical tissues. Pinocembrin pretreatment improved renal function and renal Oat3 function and reduced oxidative stress and apoptotic conditions. These findings indicate that pinocembrin has a protective effect against gentamicin-induced nephrotoxicity, which may be due in part to its antioxidant and anti-apoptotic effects, subsequently leading to improved renal function.

Alleviation of renal mitochondrial dysfunction and apoptosis underlies the protective effect of sitagliptin in gentamicin-induced nephrotoxicity

OBJECTIVE

This study aimed to investigate the potential protective effect of sitagliptin on gentamicin-induced nephrotoxicity and to elucidate the underlying mechanism.

METHODS

Wistar rats were allocated as follows: Gentamicin group: received gentamicin intraperitoneally (100 mg/kg/day); Gentamicin plus sitagliptin group: received simultaneous gentamicin and sitagliptin (30 mg/kg/day orally); Sitagliptin group: received only sitagliptin; and

CONTROL GROUP

received saline. Blood urea nitrogen (BUN), serum creatinine, urine protein levels and histopathology of kidney tissues were evaluated. The activity of mitochondrial enzyme complexes reflects the mitochondrial function. Oxidative stress biomarkers and immunohistochemical studies for apoptotic markers caspase-3 and bax were evaluated.

KEY FINDINGS

Gentamicin causes significant elevation of BUN, serum creatinine and urine proteins. Oxidative stress was revealed by decreased superoxide dismutase activity and catalase activity, glutathione depletion and increased malondialdehyde. Significant decrease in mitochondrial NADH dehydrogenase, succinate dehydrogenase, cytochrome c oxidase and mitochondrial redox activity indicates mitochondrial dysfunction, along with significant elevation in renal caspase-3 and bax. The aforementioned markers and the histological injury in renal tubules were significantly reversed upon sitagliptin treatment.

CONCLUSION

These findings suggest that sitagliptin treatment attenuates renal dysfunction and structural damage through the reduction of oxidative stress, mitochondrial dysfunction and apoptosis in the kidney.

Xenon Protects Against Septic Acute Kidney Injury via miR-21 Target Signaling Pathway

Objectives:

Septic acute kidney injury is one of the most common and life-threatening complications in critically ill patients, and there is no approved effective treatment. We have shown xenon provides renoprotection against ischemia-reperfusion injury and nephrotoxicity in rodents via inhibiting apoptosis. Here, we studied the effects of xenon preconditioning on septic acute kidney injury and its mechanism.

Design:

Experimental animal investigation.

Setting:

University research laboratory.

Subjects:

Experiments were performed with male C57BL/6 mice, 10 weeks of age, weighing 20–25 g.

Interventions:

We induced septic acute kidney injury by a single intraperitoneal injection of Escherichia coli lipopolysaccharide at a dose of 20 mg/kg. Mice were exposed for 2 hours to either 70% xenon or 70% nitrogen, 24 hours before the onset of septic acute kidney injury. In vivo knockdown of miR-21 was performed using locked nucleic acid-modified anti-miR, the role of miR-21 in renal protection conferred by the xenon preconditioning was examined, and miR-21 signaling pathways were analyzed.

Measurements and Main Results:

Xenon preconditioning provided morphologic and functional renoprotection, characterized by attenuation of renal tubular damage, apoptosis, and a reduction in inflammation. Furthermore, xenon treatment significantly upregulated the expression of miR-21 in kidney, suppressed proinflammatory factor programmed cell death protein 4 expression and nuclear factor-κB activity, and increased interleukin-10 production. Meanwhile, xenon preconditioning also suppressed the expression of proapoptotic protein phosphatase and tensin homolog deleted on chromosome 10, activating protein kinase B signaling pathway, subsequently increasing the expression of antiapoptotic B-cell lymphoma-2, and inhibiting caspase-3 activity. Knockdown of miR-21 upregulated its target effectors programmed cell death protein 4 and phosphatase and tensin homolog deleted on chromosome 10 expression, resulted in an increase in apoptosis, and exacerbated lipopolysaccharide-induced acute kidney injury.

Conclusion:

Our findings demonstrated that xenon preconditioning protected against lipopolysaccharide-induced acute kidney injury via activation of miR-21 target signaling pathways.

The role for microRNAs in drug toxicity and in safety assessment

INTRODUCTION

Adverse drug reactions present significant challenges that impact pharmaceutical development and are major burdens to public health services worldwide. In response to this need, the field of toxicology is rapidly expanding to identify key pathways involved in drug toxicity.

AREAS COVERED

MicroRNAs (miRNAs) are a class of small evolutionary conserved endogenous non-coding RNAs that regulate the translation of protein-coding genes. A wide range of toxicants alter miRNA levels in target organs and these altered miRNAs can also be detected in easily accessible biological fluids. This, combined with an early miRNA response to toxic insults and miRNA stability, substantiates the potential for these small molecules to be useful biomarkers for drug safety assessment.

EXPERT OPINION

miRNAs are early indicators and useful tools to detect drug-induced toxicity. Incorporation of miRNA profiling into the drug safety testing process will complement currently used techniques and may substantially enhance drug safety. With the increasing interests in translational research, the field of miRNA biomarker research will continue to expand and become an important part of the investigation of human drug toxicity.

Genotoxicity and cytotoxicity induced by municipal effluent in multiple organs of Wistar rats

The aim of this study was to evaluate cytotoxicity and genotoxicity in multiple organs of rats induced by municipal effluent released by submarine outfall in city of Santos. A total of 20 male Wistar rats were exposed to effluents by drinking water ad libitum at concentrations of 0, 10, 50, and 100 % for 30 days. Microscopic analysis revealed severe lesions such as necrosis and hemorrhagic areas in liver and kidney from animals exposed to effluent at 50 and 100 % concentration. DNA damage in peripheral blood, liver, and kidney cells were detected by comet assay at higher concentrations of effluent. Moreover, a decrease DNA repair capacity was detected in liver cells. Significant statistical differences (p<0.05) for micronucleated cells from liver were noticed at 50 % concentration of effluent. Taken together, our results demonstrate that municipal effluent is able to induce cytotoxicity and genotoxicity in multiple organs of Wistar rats.

Beetroot (Beta vulgaris L.) extract ameliorates gentamicin-induced nephrotoxicity associated oxidative stress, inflammation, and apoptosis in rodent model

The present investigation was designed to investigate the protective effect of (Beta vulgaris L.) beat root ethanolic extract (BVEE) on gentamicin-induced nephrotoxicity and to elucidate the potential mechanism. Serum specific kidney function parameters (urea, uric acid, total protein, creatinine, and histopathology of kidney tissue) were evaluated to access gentamicin-induced nephrotoxicity. The oxidative/nitrosative stress (Lipid peroxidation, MDA, NP-SH, Catalase, and nitric oxide levels) was assessed. The inflammatory response (TNF-α, IL-6, MPO, NF-κB (p65), and NF-κB (p65) DNA binding) and apoptotic marker (Caspase-3, Bax, and Bcl-2) were also evaluated. BVEE (250 and 500 mg/kg) treatment along with gentamicin restored/increased the renal endogenous antioxidant status. Gentamicin-induced increased renal inflammatory cytokines (TNF-α and IL-6), nuclear protein expression of NF-κB (p65), NF-κB-DNA binding activity, myeloperoxidase (MPO) activity, and nitric oxide level were significantly down regulated upon BVEE treatment. In addition, BVEE treatment significantly reduced the amount of cleaved caspase 3 and Bax, protein expression and increased the Bcl-2 protein expression. BVEE treatment also ameliorated the extent of histologic injury and reduced inflammatory infiltration in renal tubules. These findings suggest that BVEE treatment attenuates renal dysfunction and structural damage through the reduction of oxidative stress, inflammation, and apoptosis in the kidney.

Gingerol fraction from Zingiber officinale protects against gentamicin-induced nephrotoxicity

Nephrotoxicity is the main complication of gentamicin (GM) treatment. GM induces renal damage by overproduction of reactive oxygen species and inflammation in proximal tubular cells. Phenolic compounds from ginger, called gingerols, have been demonstrated to have antioxidant and anti-inflammatory effects. We investigated if oral treatment with an enriched solution of gingerols (GF) would promote a nephroprotective effect in an animal nephropathy model. The following six groups of male Wistar rats were studied: (i) control group (CT group); (ii) gingerol solution control group (GF group); (iii) gentamicin treatment group (GM group), receiving 100 mg/kg of body weight intraperitoneally (i.p.); and (iv to vi) gentamicin groups also receiving GF, at doses of 6.25, 12.5, and 25 mg/kg, respectively (GM+GF groups). Animals from the GM group had a significant decrease in creatinine clearance and higher levels of urinary protein excretion. This was associated with markers of oxidative stress and nitric oxide production. Also, there were increases of the mRNA levels for proinflammatory cytokines (tumor necrosis factor alpha [TNF-α], interleukin-1β [IL-1β], IL-2, and gamma interferon [IFN-γ]). Histopathological findings of tubular degeneration and inflammatory cell infiltration reinforced GM-induced nephrotoxicity. All these alterations were attenuated by previous oral treatment with GF. Animals from the GM+GF groups showed amelioration in renal function parameters and reduced lipid peroxidation and nitrosative stress, in addition to an increment in the levels of glutathione (GSH) and superoxide dismutase (SOD) activity. Gingerols also promoted significant reductions in mRNA transcription for TNF-α, IL-2, and IFN-γ. These effects were dose dependent. These results demonstrate that GF promotes a nephroprotective effect on GM-mediated nephropathy by oxidative stress, inflammatory processes, and renal dysfunction.