Review article: the role of tumor necrosis factor in renal ischemia-reperfusion injury

Activation of Purinergic P2Y2 Receptor Protects the Kidney Against Renal Ischemia and Reperfusion Injury in Mice

Extracellular ATP plays an important role in renal physiology as well as the pathogenesis of acute kidney injury induced by renal ischemia and reperfusion (IR). Expression of the purinergic P2Y2 receptor has been shown on inflammatory and structural cells of the kidney, and P2Y2R is preferably activated by ATP (or UTP). Here, we investigated the molecular mechanism of P2Y2R during IR injury by using P2Y2R knockout (KO) mice and a selective P2Y2R agonist, MRS2768. After renal IR, P2Y2R KO mice showed greater increases in plasma creatinine, tubular damage and neutrophil infiltration, and significant induction of proinflammatory cytokines and apoptotic markers than wild-type (WT) mice. In contrast, treatment with MRS2768 reduced plasma creatinine levels, tubular damage and inflammation, and renal apoptosis in mice subjected to renal IR. In cultured human proximal tubular HK-2 cells, MRS2768 upregulated P2Y2R mRNA levels and decreased TNF-α/cycloheximide-induced apoptosis and inflammation. Importantly, P2Y2R activation by MRS2768 increased the phosphorylation of protein kinase C (PKC), Src, and phosphatidylinositol 3-kinase (PI3K)/Akt. In addition, the inhibition of PI3K/Akt abolished the protective effects of MRS2768 against TNF-α/cycloheximide-induced apoptosis and inflammation in HK-2 cells. In conclusion, activation of P2Y2R protects against tubular apoptosis and inflammation during renal IR via the PKC/Src/Akt pathway, suggesting P2Y2R is a promising therapeutic target for acute kidney injury.

Inhibition of both NOX and TNF-α exerts substantial renoprotective effects in renal ischemia reperfusion injury rat model

BACKGROUND AND AIMS

Acute kidney injury (AKI) due to renal ischemia-reperfusion injury (RIRI) is associated with high morbidity and mortality, with no renoprotective drug available. Previous research focused on single drug targets, yet this approach has not reached translational success. Given the complexity of this condition, we aimed to identify a disease module and apply a multitarget network pharmacology approach.

METHODS

Identification of a disease module with potential drug targets was performed utilizing Disease Module Detection algorithm using NADPH oxidases (NOXs) as seeds. We then assessed the protective effect of a multitarget network pharmacology targeting the identified module in a rat model of RIRI. Rats were divided into five groups; sham, RIRI, and RIRI treated with setanaxib (NOX inhibitor, 10 mg/kg), etanercept (TNF-α inhibitor, 10 mg/kg), and setanaxib and etanercept (5 mg/kg each). Kidney functions, histopathological changes and oxidative stress markers (MDA and reduced GSH) were assessed. Immunohistochemistry of inflammatory (TNF-α, NF-κB) apoptotic (cCasp-3, Bax/Bcl 2), fibrotic (α-SMA) and proteolysis (MMP-9) markers was performed.

RESULTS

Our in-silico analysis yielded a disease module with TNF receptor 1 (TNFR1A) as the closest target to both NOX1 and NOX2. Targeting this module by a low-dose combination of setanaxib, and etanercept, resulted in a synergistic effect and ameliorated ischemic AKI in rats. This was evidenced by improved kidney function and reduced expression of inflammatory, apoptotic, proteolytic and fibrotic markers.

CONCLUSIONS

Our findings show that applying a multitarget network pharmacology approach allows synergistic renoprotective effect in ischemic AKI and might pave the way towards translational success.

Exploration of the shared gene signatures and biological mechanisms between ischemia-reperfusion injury and antibody-mediated rejection in renal transplantation

BACKGROUND

Antibody-mediated rejection (ABMR) plays a crucial role in graft loss during allogeneic renal transplantation. In renal transplantation, ischemia-reperfusion injury (IRI) is unavoidable, serves as a major contributor to acute rejection, and is linked to graft loss. However, the mechanisms underlying IRI and ABMR are unclear. Therefore, this study aimed to investigate the shared genetic characteristics and biological mechanisms between IRI and ABMR.

METHODS

Gene expressions for IRI (GSE43974) and ABMR (GSE129166 and GSE36059) were retrieved from the Gene Expression Omnibus database. The shared differentially expressed genes (DEGs) of IRI and ABMR were identified, and subsequent functional enrichment analysis was performed. Immune cell infiltration in ABMR and its relationship with the shared DEGs were investigated using the CIBERSORT method. Random forest analysis, a protein-protein interaction network, and Cytoscape were used to screen hub genes, which were subsequently subjected to gene set enrichment analysis, miRNA prediction, and transcription factors analysis. The survival analysis was performed through Kaplan-Meier curves. Finally, drug compound prediction was performed on the shared DEGs using the Drug Signature Database.

RESULTS

Overall, 27 shared DEGs were identified between the renal IRI and ABMR groups. Among these, 24 genes exhibited increased co-expression, whereas none showed decreased co-expression. The shared DEGs were primarily enriched in the inflammation signaling pathways. Notably, CD4 memory T cells were identified as potential critical mediators of IRI, leading to ABMR. Tumor necrosis factor alpha-induced protein 3 (TNFAIP3), interferon regulatory factor 1 (IRF1), and early growth response 2 (EGR2) were identified as key components in the potential mechanism that link IRI and ABMR. Patients undergoing renal transplantation with higher expression levels of TNFAIP3, IRF1, and EGR2 exhibited decreased survival rates compared to those with lower expression levels.

CONCLUSION

Inflammation is a key mechanism that links IRI and ABMR, with a potential role played by CD4 memory T cells. Furthermore, TNFAIP3, IRF1, and EGR2 are implicated in the underlying mechanism between IRI and ABMR.

Cyclosporine-induced kidney damage was halted by sitagliptin and hesperidin via increasing Nrf2 and suppressing TNF-α, NF-κB, and Bax

Cyclosporine A (CsA) is employed for organ transplantation and autoimmune disorders. Nephrotoxicity is a serious side effect that hampers the therapeutic use of CsA. Hesperidin and sitagliptin were investigated for their antioxidant, anti-inflammatory, and tissue-protective properties. We aimed to investigate and compare the possible nephroprotective effects of hesperidin and sitagliptin. Male Wistar rats were utilized for induction of CsA nephrotoxicity (20 mg/kg/day, intraperitoneally for 7 days). Animals were treated with sitagliptin (10 mg/kg/day, orally for 14 days) or hesperidin (200 mg/kg/day, orally for 14 days). Blood urea, serum creatinine, albumin, cystatin-C (CYS-C), myeloperoxidase (MPO), and glucose were measured. The renal malondialdehyde (MDA), glutathione (GSH), catalase, and SOD were estimated. Renal TNF-α protein expression was evaluated. Histopathological examination and immunostaining study of Bax, Nrf-2, and NF-κB were performed. Sitagliptin or hesperidin attenuated CsA-mediated elevations of blood urea, serum creatinine, CYS-C, glucose, renal MDA, and MPO, and preserved the serum albumin, renal catalase, SOD, and GSH. They reduced the expressions of TNF-α, Bax, NF-κB, and pathological kidney damage. Nrf2 expression in the kidney was raised. Hesperidin or sitagliptin could protect the kidney against CsA through the mitigation of oxidative stress, apoptosis, and inflammation. Sitagliptin proved to be more beneficial than hesperidin.

The role of non-protein-coding RNAs in ischemic acute kidney injury

Acute kidney injury (AKI) is a condition characterized by a rapid decline in kidney function within a span of 48 hours. It is influenced by various factors including inflammation, oxidative stress, excessive calcium levels within cells, activation of the renin-angiotensin system, and dysfunction in microcirculation. Ischemia-reperfusion injury (IRI) is recognized as a major cause of AKI; however, the precise mechanisms behind this process are not yet fully understood and effective treatments are still needed. To enhance the accuracy of diagnosing AKI during its early stages, the utilization of innovative markers is crucial. Numerous studies suggest that certain noncoding RNAs (ncRNAs), such as long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), play a central role in regulating gene expression and protein synthesis. These ncRNAs are closely associated with the development and recovery of AKI and have been detected in both kidney tissue and bodily fluids. Furthermore, specific ncRNAs may serve as diagnostic markers and potential targets for therapeutic interventions in AKI. This review aims to summarize the functional roles and changes observed in noncoding RNAs during ischemic AKI, as well as explore their therapeutic potential.

Pharmacological functions of salidroside in renal diseases: facts and perspectives

Rhodiola rosea is a valuable functional medicinal plant widely utilized in China and other Asian countries for its anti-fatigue, anti-aging, and altitude sickness prevention properties. Salidroside, a most active constituent derived from Rhodiola rosea, exhibits potent antioxidative, hypoxia-resistant, anti-inflammatory, anticancer, and anti-aging effects that have garnered significant attention. The appreciation of the pharmacological role of salidroside has burgeoned over the last decade, making it a beneficial option for the prevention and treatment of multiple diseases, including atherosclerosis, Alzheimer's disease, Parkinson's disease, cardiovascular disease, and more. With its anti-aging and renoprotective effects, in parallel with the inhibition of oxidative stress and inflammation, salidroside holds promise as a potential therapeutic agent for kidney damage. This article provides an overview of the microinflammatory state in kidney disease and discuss the current therapeutic strategies, with a particular focus on highlighting the recent advancements in utilizing salidroside for renal disease. The potential mechanisms of action of salidroside are primarily associated with the regulation of gene and protein expression in glomerular endothelial cells, podocytes, renal tubule cells, renal mesangial cells and renal cell carcinoma cell, including TNF-α, TGF-β, IL-1β, IL-17A, IL-6, MCP-1, Bcl-2, VEGF, ECM protein, caspase-3, HIF-1α, BIM, as well as the modulation of AMPK/SIRT1, Nrf2/HO-1, Sirt1/PGC-1α, ROS/Src/Cav-1, Akt/GSK-3β, TXNIP-NLRP3, ERK1/2, TGF-β1/Smad2/3, PI3K/Akt, Wnt1/Wnt3a β-catenin, TLR4/NF-κB, MAPK, JAK2/STAT3, SIRT1/Nrf2 pathways. To the best of our knowledge, this review is the first to comprehensively cover the protective effects of salidroside on diverse renal diseases, and suggests that salidroside has great potential to be developed as a drug for the prevention and treatment of metabolic syndrome, cardiovascular and cerebrovascular diseases and renal complications.

Comprehensive Overview of Innovative Strategies in Preventing Renal Ischemia-reperfusion Injury: Insights from Bibliometric and In silico Analyses

BACKGROUND

Ischemia-reperfusion Injury (IRI) is a complex pathophysiological process with severe consequences, including irreversible loss of renal function. Various intraoperative prevention methods have been proposed to mitigate the harmful effects of warm ischemia and kidney reperfusion.

AIM

This comprehensive analysis provides an overview of pharmacological agents and intraoperative methods for preventing and treating renal IRI.

METHODS

Our analysis revealed that eplerenone exhibited the highest binding affinity to crucial targets, including Aldehyde Dehydrogenase (AD), Estrogen Receptor (ER), Klotho protein, Mineralocorticoid Receptor (MR), and Toll-like Receptor 4 (TLR4). This finding indicates eplerenone's potential as a potent preventive agent against IRI, surpassing other available therapeutics like Benzodioxole, Hydrocortisone, Indoles, Nicotinamide adenine dinucleotide, and Niacinamide. In preventing kidney IRI, our comprehensive analysis emphasizes the significance of eplerenone due to its strong binding affinity to key targets involved in the pathogenesis of IRI.

RESULTS

This finding positions eplerenone as a promising candidate for further clinical investigation and consideration for future clinical practice.

CONCLUSION

The insights provided in this analysis will assist clinicians and researchers in selecting effective preventive approaches for renal IRI in surgical settings, potentially improving patient outcomes.

Short-term association of CO and NO2 with hospital visits for glomerulonephritis in Hefei, China: a time series study

Objective

Recent studies suggest air pollution as an underlying factor to kidney disease. However, there is still limited knowledge about the short-term correlation between glomerulonephritis (GN) and air pollution. Thus, we aim to fill this research gap by investigating the short-term correlation between GN clinical visits and air pollution exposure.

Methods

Between 2015 and 2019, daily GN visit data from two grade A tertiary hospitals in Hefei City were collected, along with corresponding air pollution and meteorological data. A generalized linear model integrated with a distributed lag nonlinear model was employed to analyze the relationship between GN visits and air pollutants. Moreover, we incorporated a dual pollutant model to account for the combined effects of multiple pollutants. Furthermore, subgroup analyses were performed to identify vulnerable populations based on gender, age, and season.

Results

The association between 23,475 GN visits and air pollutants was assessed, and significant positive associations were found between CO and NO2 exposure and GN visit risk. The single-day lagged effect model for CO showed increased risks for GN visits from lag0 (RR: 1.129, 95% CI: 1.031-1.236) to lag2 (RR: 1.034, 95% CI: 1.011-1.022), with the highest risk at lag0. In contrast, NO2 displayed a more persistent impact (lag1-lag4) on GN visit risk, peaking at lag2 (RR: 1.017, 95% CI: 1.011-1.022). Within the dual-pollutant model, the significance persisted for both CO and NO2 after adjusting for each other. Subgroup analyses showed that the cumulative harm of CO was greater in the cold-season and older adult groups. Meanwhile, the female group was more vulnerable to the harmful effects of cumulative exposure to NO2.

Conclusion

Our study indicated that CO and NO2 exposure can raise the risk of GN visits, and female and older adult populations exhibited greater susceptibility.

The combined effect of zinc oxide nanoparticles and milrinone on acute renal ischemia/reperfusion injury in rats: Potential underlying mechanisms

AIM

To investigate the efficacy of zinc oxide nanoparticles (ZnO-NPs) and/or milrinone (MIL) on renal ischemia/reperfusion injury (I/RI) in rats and their possible underlying mechanisms.

MATERIALS AND METHODS

Forty-eight adult male Sprague-Dawley albino rats were randomly assigned into six equal-sized groups (n = 8): normal control, sham-operated, I/R group (45 min/24 h), ZnO-NPs group (10 mg/Kg i.p.), MIL group (0.5 mg/Kg i.p.), and ZnO-NPs + MIL group in the same previous doses.

KEY FINDINGS

In comparison to the I/R-operated group, administration of either ZnO-NPs or MIL significantly decreased serum creatinine and urea concentrations, and renal vascular permeability (p < 0.05). The oxidative stress was significantly declined, as evidenced by increased GPx, CAT, and SOD activities and decreased MDA and NO concentrations. Renal expressions of TNF-α, NF-κB, KIM-1, NGAL, and caspase-3 decreased significantly, while Nrf2 increased significantly. Histopathology investigation revealed improvement with minimal renal lesions and fibrosis after ZnO-NPs or MIL treatments. The combined treatments synergistically improved the studied parameters more than either treatment alone. These findings were validated by molecular modeling, which revealed that MIL inhibited TNF-α, NF-kB, caspase-3, KIM-1 and NGAL.

SIGNIFICANCE

Both ZnO-NPs and MIL exerted cytoprotective effects against acute renal I/RI, and a combination of both was found to be even more effective. This renoprotective effect is suggested to be mediated through activation of Nrf2 and the prevention of the NF-κB activation-induced oxidative stress and inflammation, which may strengthen the potential role of ZnO-NPs or MIL in renal I/RI protection during surgical procedures.

H2O2-Activatable Antioxidant Polymeric Prodrug Nanoparticles for the Prevention of Renal Ischemia/Reperfusion Injury

Renal ischemia-reperfusion (IR) injury is an inevitable complication in various clinical settings including kidney transplantation and major vascular surgeries. Renal IR injury is a major risk factor for acute kidney injury, which still remains a major clinical challenge without effective therapy. The main cause of renal IR injury is the massive production of reactive oxygen species (ROS) including hydrogen peroxide (H₂O₂) that initiate inflammatory signaling pathways, leading to renal cell death. In this study, we developed fucoidan-coated polymeric prodrug (Fu-PVU73) nanoparticles as renal IR-targeting nanotherapeutics that can rapidly eliminate H₂O₂ and exert anti-inflammatory and antiapoptotic effects. Fu-PVU73 nanoparticles were composed of H₂O₂-activatable antioxidant and anti-inflammatory polymeric prodrug (PVU73) that incorporated H₂O₂-responsive peroxalate linkages, ursodeoxycholic acid (UDCA), and vanillyl alcohol (VA) in its backbone. Fu-PVU73 nanoparticles rapidly scavenged H₂O₂ and released UDCA and VA during H₂O₂-triggered degradation. In the study of renal IR injury mouse models, Fu-PVU73 nanoparticles preferentially accumulated in the IR injury-induced kidney and markedly protected the kidney from IR injury by suppressing the generation of ROS and the expression of proinflammatory cytokines. We anticipate that Fu-PVU73 nanoparticles have tremendous therapeutic potential for not only renal IR injury but also various ROS-associated inflammatory diseases.

Melatonin attenuates hepatic ischemia-reperfusion injury in rats by inhibiting NF-κB signaling pathway

BACKGROUND

The sterile inflammatory response is one of the key mechanisms leading to hepatic ischemia-reperfusion injury. Melatonin has been shown to prevent organ injuries, but its roles in the inflammatory response after hepatic ischemia-reperfusion injury have not been fully explored, especially in late ischemia-reperfusion injury. The present study aimed to investigate the roles and possible mechanisms of melatonin in the inflammatory response after hepatic ischemia-reperfusion injury.

METHODS

Sixty Sprague-Dawley rats were randomly divided into a sham group, ischemia-reperfusion injury group (I/R group), and melatonin-treated group (M + I/R group). The rats in the I/R group were subjected to 70% hepatic ischemia for 45 min, followed by 5 or 24 h of reperfusion. The rats in the M + I/R group were injected with melatonin (10 mg/kg, intravenous injection) 15 min prior to ischemia and immediately before reperfusion. Serum and samples of ischemic liver lobes were harvested for future analysis, and the 7-day survival rate was assessed after hepatic ischemia-reperfusion surgery.

RESULTS

In comparison with the I/R group, the M + I/R group showed markedly decreased expression levels of inflammatory cytokines (IL-6 and TNF-α) and numbers of apoptotic hepatocytes (P < 0.05). Immunoblotting showed that the expression levels of IL-6, p-NF-κBp65/t-NF-κBp65 and p-IκB-α/t-IκB-α in the M + I/R group were significantly lower than those in the I/R group, and immunofluorescence staining showed that the expression level of p-NF-κBp65 in the M + I/R group was lower than that in the I/R group (P < 0.05). The 7-day survival rates were 20% in the I/R group and 50% in the M + I/R group (P < 0.05).

CONCLUSIONS

Melatonin downregulated the activity of the NF-κB signaling pathway in the early and late stages of hepatic ischemia-reperfusion injury, alleviated the inflammatory response, protected the liver from ischemia-reperfusion injury, and increased the survival rate.

Penehyclidine hydrochloride ameliorates renal ischemia reperfusion-stimulated lung injury in mice by activating Nrf2 signaling

Introduction: Penehyclidine hydrochloride (PHC) is an anticholinergic with anti-inflammatory and anti-oxidation activities. PHC displayed protectivity against renal ischemia reperfusion (RIR) injury. Nevertheless, the precise protectivity of PHC on RIR-induced lung injury remains unknown. Methods: We examined the effects of PHC on RIR-induced lung injury and investigated the underlying mechanism. We induced RIR in mice and administrated PHC to RIR mice. Kidney function was monitored by measuring the blood urea nitrogen (BUN) and creatinine level in serum. We evaluated the lung injury, myeloperoxidase (MPO) activity in lung, pro-inflammatory cytokine level, and oxidative markers in serum and lung tissues. We tested the expression level of nuclear factor erythroid 2-related factor 2 (Nrf-2) and heme oxygenase 1 (HO-1) in lung of RIR mice after PHC treatment. Finally, we evaluated the effects of PHC in RIR Nrf2^-/- mice. Results: PHC greatly downregulated the serum levels of BUN, creatinine, IL-6, NO, malondialdehyde (MDA), and matrix metalloproteinase-2. PHC also ameliorated the lung injury, decreased the MPO activity, and suppressed production of IL-6, TNF-α, IFN-γ, MDA, and O2-, while it promoted production of superoxide dismutase (SOD) and catalase (CAT) in lung. PHC improved the production of Nrf2 and HO-1. Conclusion: The protectivity of PHC was absent in Nrf2^-/- mice. PHC ameliorated RIR-induced lung injury through Nrf2 pathway.

The protective effects of sinapic acid on acute renal ischemia/reperfusion injury

Objectives

The aim of this research was to investigate whether sinapic acid (SA) can alleviate oxidative damage, apoptosis, and inflammation in I/R induced renal injury.

Methods

A total of 24 male rats were randomly separated into four groups as six rats in each group. Group 1 (Sham), Group 2 (I/R), Group 3 (I/R + SA, 10 mg/kg), Group 4 (I/R + SA, 20 mg/kg). In order to evaluate kidney function serum BUN, Cr, and AST were measured in an autoanalyzer. SOD, GSH-Px, MDA, PC and NO oxidative stress parameters were measured with spectrophotometric methods and TNF-α, IL-1β, IL-6, KIM-1 and NGAL parameters were measured with the ELISA method. In addition, H&E method and immunohistochemical examinations were performed for histological evaluations of kidney tissue.

Results

SA significantly decreases the increase in kidney damage, inflammation, oxidative stress, cell death and restore the decrease in antioxidant enzyme activities (p<0.05). Pre-treatment of the rats with SA reduces kidney dysfunction and morphological changes.

Conclusions

The development of oxidative stress and lipid peroxidation seems to be the leading factors that accelerate inflammation and cell death during renal IRI. The antioxidant, anti-inflammatory, and anti-apoptotic features of SA displayed a renoprotective effect.

Recent Approaches to Targeting Canonical NFκB Signaling in the Early Inflammatory Response to Renal IRI

Ischemia reperfusion injury (IRI) is the most common cause of in-hospital AKI and is associated with increased morbidity and mortality. IRI is associated with an early phase of inflammation primarily regulated by the canonical NFκB signaling pathway. Despite recent advances in our understanding of the pathogenesis of IRI, few therapeutic strategies have emerged. The purpose of this manuscript is to review interventions targeting NFκB after IRI.

Nephroprotective role of diosgenin in gentamicin-induced renal toxicity: biochemical, antioxidant, immunological and histopathological approach

Background

Aminoglycoside antibiotics, gentamicin (GM) owns the utmost nephrotoxic potential than other antibiotics from the same category. To the other side, diosgenin (DG) showed the antioxidant and anti-inflammatory property.

Results

The present study was aimed to explore the nephroprotective effect of diosgenin on gentamicin-induced renal toxicity in Wistar rats. Wistar albino rats were divided into six groups (n = 6): Normal control (NC), Nephrotoxicity control (GM), DG (20 mg/kg), DG (40 mg/kg), DG (80 mg/kg), accordingly. After the treatment, the nephroprotective effects of DG were assessed by measuring serum levels of creatinine (Cr), blood urea nitrogen (BUN), total proteins (TP), albumin and urea levels. Urine volume, proteins, electrolyte levels, creatinine clearance were also evaluated in urine samples. Oxidative stress was evaluated through the measurement of antioxidant stress markers in the kidney tissue. Changes in body weight and kidney weight were also recorded along with a histopathological examination of kidney sections. For evaluation of inflammation, TNF-α and IL-1β levels were measured in the blood serum using ELISA kits. GM intoxication induced elevated serum creatinine, BUN, urea, albumin and TP levels, urine electrolytes levels, pro-inflammatory cytokines, antioxidant parameters which were found to be decreased significantly in a dose-dependent manner in rat groups received DG which was also evidenced by the histological observations.

Conclusion

DG showed a significant nephroprotective effect in a dose-dependent manner by ameliorating the GM induced nephrotoxicity in Wistar rats.

Dissecting Efficacy and Metabolic Characteristic Mechanism of Taxifolin on Renal Fibrosis by Multivariate Approach and Ultra-Performance Liquid Chromatography Coupled With Mass Spectrometry-Based Metabolomics Strategy

Taxifolin (TFN) is an important natural compound with antifibrotic activity; however, its pharmacological mechanism is not clear. In this study, our aim is to gain insight into the effects of TFN and its potential mechanisms in unilateral ureteral obstruction (UUO) animal model using metabolomics approach to identify the metabolic biomarkers and perturbed pathways. Serum metabolomics analysis by UPLC-Q-TOF/MS was carried out to discover the changes in the metabolic profile. It showed that TFN has a significant protective effect on UUO-induced renal fibrosis and a total of 32 potential biomarkers were identified and related to RF progression. Of note, 27 biomarkers were regulated by TFN treatment, which participate in eight metabolic pathways, including phenylalanine, tyrosine and tryptophan biosynthesis, and phenylalanine metabolism. It also showed that metabolomics was a promising strategy to better dissect metabolic characteristics and pharmacological mechanisms of natural compounds by multivariate approach and ultra-performance liquid chromatography coupled with mass spectrometry.

Investigating the Effect of Near Infra-Red Spectroscopy (NIRS) on Early Diagnosis of Cardiac Surgery-Associated Acute Kidney Injury

Background

Cardiac surgery-associated acute kidney injury (CSA-AKI) is a major adverse effect of cardiac surgery. The early detection of this complication can improve the quality of postoperative care and help prevent this phenomenon.

Methods

In this prospective descriptive-analytical study, 148 patients were enrolled, 107 of whom were selected for analysis between February and September 2019 in the Cardiac Surgery Unit of Golestan Hospital, Ahvaz, Iran. Kidney tissue oxygen saturation was measured at multiple definite times during surgery. Hemoglobin, blood urea nitrogen, creatinine, and lactate were measured during and 48 hours after the surgery.

Results

Forty-one patients were diagnosed with CSA-AKI according to the KDIGO criteria. Parametric and non-parametric analyses showed no significant difference between the CSA-AKI and non-CSA-AKI groups in the demographic parameters. Repeated measures ANOVA showed no significant difference in parameters, except for BUN. Repeated measures ANOVA showed a significant difference between both groups and time factors (P < 0.001, P = 0.0006, respectively). The ROC curve analyses showed that in a single point of time, the difference in the middle of CPB time from baseline had a high value in the prediction of AKI (AUC: 0.764; CI: 0.57 - 0.951).

Conclusions

Kidney saturation monitoring could be considered in cardiac surgery for the rapid detection of CSA-AKI. Although kidney tissue saturation is not correlated directly to the arterial oxygen saturation, the physician and the surgery team can predict the chance of acute kidney injury.

Inhibition of BRD4 Reduces Neutrophil Activation and Adhesion to the Vascular Endothelium Following Ischemia Reperfusion Injury

Renal ischemia reperfusion injury (IRI) is associated with inflammation, including neutrophil infiltration that exacerbates the initial ischemic insult. The molecular pathways involved are poorly characterized and there is currently no treatment. We performed an in silico analysis demonstrating changes in NFκB-mediated gene expression in early renal IRI. We then evaluated NFκB-blockade with a BRD4 inhibitor on neutrophil adhesion to endothelial cells in vitro, and tested BRD4 inhibition in an in vivo IRI model. BRD4 inhibition attenuated neutrophil adhesion to activated endothelial cells. In vivo, IRI led to increased expression of cytokines and adhesion molecules at 6 h post-IRI with sustained up-regulated expression to 48 h post-IRI. These effects were attenuated, in part, with BRD4 inhibition. Absolute neutrophil counts increased significantly in the bone marrow, blood, and kidney 24 h post-IRI. Activated neutrophils increased in the blood and kidney at 6 h post-IRI and remained elevated in the kidney until 48 h post-IRI. BRD4 inhibition reduced both total and activated neutrophil counts in the kidney. IRI-induced tubular injury correlated with neutrophil accumulation and was reduced by BRD4 inhibition. In summary, BRD4 inhibition has important systemic and renal effects on neutrophils, and these effects are associated with reduced renal injury.

Neuroimmune Mechanisms in Signaling of Pain During Acute Kidney Injury (AKI)

Acute kidney injury (AKI) is a significant global health concern. The primary causes of AKI include ischemia, sepsis and nephrotoxicity. The unraveled interface between nervous system and immune response with specific focus on pain pathways is generating a huge interest in reference to AKI. The nervous system though static executes functions by nerve fibers throughout the body. Neuronal peptides released by nerves effect the immune response to mediate the hemodynamic system critical to the functioning of kidney. Pain is the outcome of cellular cross talk between nervous and immune systems. The widespread release of neuropeptides, neurotransmitters and immune cells contribute to bidirectional neuroimmune cross talks for pain manifestation. Recently, we have reported pain pathway genes that may pave the way to better understand such processes during AKI. An auxiliary understanding of the functions and communications in these systems will lead to novel approaches in pain management and treatment through the pathological state, specifically during acute kidney injury.

Effect of infusion of M&G solution for protection of renal tissue in Wistar rats subjected to programmed ischemia-reperfusion

Background

Renal ischemia-reperfusion (I/R) is directly associated with acute renal failure and can occur in conditions such as infarction caused by embolization or thrombosis, septicemia, and kidney transplantation. The process is complex, involving innate and adaptive immune responses, presence of cellular infiltrate, and production and release of cytokines and chemokines. It also triggers cell responses and release of reactive oxygen species, in addition to causing apoptosis and, in some cases, cell necrosis. Against this background, evaluation of renal tissue protection mechanisms is essential.

Objectives

The objective of this study was to test the M&G solution, developed in prior research, evaluating its capacity to protect the kidneys using morphometric analysis and by assaying the presence and expression of inflammatory cytokines (TNF-alpha, VEGF, HIF, and IL-8).

Methods

Eighteen Wistar rats were divided into three groups: Sham (S), Control (C), and Experimental (E). The S group underwent the surgical operation, but without arterial clamping. In group C, the aorta was clamped above and below the left renal artery, without infusion of the preservation solution. In group E, in addition to clamping, the aorta was punctured and M&G solution was infused continuously for 20 minutes at 15^o C. Morphological analysis and immunohistochemical assessment of markers were then conducted.

Results

Morphological differences were identified in group S compared with groups C and E. Analysis of markers revealed reduced intensity of expression of TNF and of VEGF in group E. There were no differences in HIF or IL-8 between groups.

Conclusions

The M&G solution was associated with a reduction in presence and expression of TNF-alpha and a trend to reduced VEGF.

NF-κB and tPA Signaling in Kidney and Other Diseases

The activation of the nuclear factor-κB (NF-κB) pathway plays a central role in the initiation and progression of inflammation, which contributes to the pathogenesis and progression of various human diseases including kidney, brain, and other diseases. Tissue plasminogen activator (tPA), a serine protease regulating homeostasis of blood coagulation, fibrinolysis, and matrix degradation, has been shown to act as a cytokine to trigger profound receptor-mediated intracellular events, modulate the NF-κB pathway, and mediate organ dysfunction and injury. In this review, we focus on the current understanding of NF-κB and tPA signaling in the development and progression of kidney disease. Their roles in the nervous and cardiovascular system are also briefly discussed.

Uncoupling protein 2 prevents ischaemia reperfusion injury through the regulation ROS/NF-κB signalling in mice

Background and objective: Renal ischaemia reperfusion injury (IRI), characterized by excessive cell apoptosis and inflammation, remains a clinical challenge. Mitochondrial membrane potential is related to apoptosis and inflammation of IRI. Previous studies have indicated that uncoupling protein 2 (UCP2) and its receptors play an important role in inflammation, apoptosis and injuries, especially in oxidative stress injury. However, the underlying mechanisms of UCP2 in IRI are still not fully understood.Methods and results: In the present study, male C57 mice were randomly divided into three groups:sham, IR, and UCP2^-/-+IR. The IRI model was established by removing the right kidney and clamping the left kidney for 45 min followed by reperfusion. Blood urea nitrogen (BUN) and creatinine were higher in UCP2^-/-+IR mouse serum than in IR mouse serum. In addition, relative to the IR group, UCP2^-/-+IR mouse renal cells had increased reactive oxygen species (ROS) production, aggravating tissue damage. We examined changes in the NFκB pathway and found that after UCP2 knockdown, IκB and IKK phosphorylation increased, and nuclear NFκB increased, which stimulated inflammation. Moreover, there was an increase in apoptosis in the UCP2^-/-+IR group.Conclusion: UCP2 can prevent IRI in C57 mice. Mechanistically, UCP2 may decrease ROS expression, NFκB activation and caspase-3 cleavage, rendering UCP2 a potential therapeutic target against IRI.

Monophosphoryl lipid A pretreatment suppresses sepsis- and LPS-induced proinflammatory cytokine production in the medullary thick ascending limb

Sepsis is the leading cause of acute kidney injury in critically ill patients. Tumor necrosis factor-α (TNF-α) has been implicated in the pathogenesis of septic kidney injury; however, the sites and mechanisms of renal TNF-α production during sepsis remain to be defined. In the present study, we showed that TNF-α expression is increased in medullary thick ascending limbs (MTALs) of mice with sepsis induced by cecal ligation and puncture. Treatment with lipopolysaccharide (LPS) for 3 h in vitro also increased MTAL TNF-α production. Sepsis and LPS increased MTAL TNF-α expression through activation of the myeloid differentiation factor 88 (MyD88)-IL-1 receptor-associated kinase 1-ERK signaling pathway. Pretreatment with monophosphoryl lipid A (MPLA), a nontoxic immunomodulator that protects against bacterial infection, eliminated the sepsis- and LPS-induced increases in MTAL TNF-α production. The suppressive effect of MPLA on TNF-α was mediated through activation of a phosphatidylinositol 3-kinase-dependent pathway that inhibits MyD88-dependent ERK activation. This likely involves MPLA-phosphatidylinositol 3-kinase-mediated induction of Tollip, which negatively regulates the MyD88-ERK pathway by inhibiting activation of IL-1 receptor-associated kinase 1. These regulatory mechanisms are similar to those previously shown to mediate the effect of MPLA to prevent sepsis-induced inhibition of MTAL [Formula: see text] absorption. These results identify the MTAL as a site of local TNF-α production in the kidney during sepsis and identify molecular mechanisms that can be targeted to attenuate renal TNF-α expression. The ability of MPLA pretreatment to suppress MyD88-dependent ERK signaling in the MTAL during sepsis has the dual beneficial effects of protecting tubule transport functions and attenuating harmful proinflammatory responses.

Transplanting Marginal Organs in the Era of Modern Machine Perfusion and Advanced Organ Monitoring

Organ transplantation is undergoing profound changes. Contraindications for donation have been revised in order to better meet the organ demand. The use of lower-quality organs and organs with greater preoperative damage, including those from donation after cardiac death (DCD), has become an established routine but increases the risk of graft malfunction. This risk is further aggravated by ischemia and reperfusion injury (IRI) in the process of transplantation. These circumstances demand a preservation technology that ameliorates IRI and allows for assessment of viability and function prior to transplantation. Oxygenated hypothermic and normothermic machine perfusion (MP) have emerged as valid novel modalities for advanced organ preservation and conditioning. Ex vivo prolonged lung preservation has resulted in successful transplantation of high-risk donor lungs. Normothermic MP of hearts and livers has displayed safe (heart) and superior (liver) preservation in randomized controlled trials (RCT). Normothermic kidney preservation for 24 h was recently established. Early clinical outcomes beyond the market entry trials indicate bioenergetics reconditioning, improved preservation of structures subject to IRI, and significant prolongation of the preservation time. The monitoring of perfusion parameters, the biochemical investigation of preservation fluids, and the assessment of tissue viability and bioenergetics function now offer a comprehensive assessment of organ quality and function ex situ. Gene and protein expression profiling, investigation of passenger leukocytes, and advanced imaging may further enhance the understanding of the condition of an organ during MP. In addition, MP offers a platform for organ reconditioning and regeneration and hence catalyzes the clinical realization of tissue engineering. Organ modification may include immunological modification and the generation of chimeric organs. While these ideas are not conceptually new, MP now offers a platform for clinical realization. Defatting of steatotic livers, modulation of inflammation during preservation in lungs, vasodilatation of livers, and hepatitis C elimination have been successfully demonstrated in experimental and clinical trials. Targeted treatment of lesions and surgical treatment or graft modification have been attempted. In this review, we address the current state of MP and advanced organ monitoring and speculate about logical future steps and how this evolution of a novel technology can result in a medial revolution.

A self-assembling peptide hydrogel-based drug co-delivery platform to improve tissue repair after ischemia-reperfusion injury

Ischemia-reperfusion (I/R)-induced organ injury is a serious health problem worldwide, and poor recovery of acute phase injury leads to chronic fibrosis and further organ dysfunction. Thus, a more precise approach to enhance tissue repair is needed. By using a renal I/R model, we aimed to evaluate the role of a hydrogel-based dual-drug delivery platform on promoting tissue repair. An injectable, self-assembling peptide/heparin (SAP/Hep) hydrogel was used to co-deliver TNF-α neutralizing antibody (anti-TNF-α) and hepatocyte growth factor (HGF). The microstructure and controlled release properties of KLD2R/Hep hydrogel were analyzed. The effects of the drug-loaded hydrogel (SAP-drug) on renal injury were evaluated in mice with I/R injury. In vitro, the SAP/Hep hydrogel allowed for a faster release of anti-TNF-α with a sustained release of HGF, and both drugs maintained their bioactivities after release. In vivo, combined anti-TNF-α/HGF showed better renal protective potential than anti-TNF-α or HGF alone. SAP-drug (anti-TNF-α/HGF in SAP hydrogel) treatment reduced the level of serum creatinine (Scr), blood urea nitrogen (BUN), tubular apoptosis, renal inflammatory factors, and macrophage infiltration compared to Free-drug (anti-TNF-α/HGF in solution) or SAP alone. Moreover, the SAP-drug group had better efficacy on promoting tubular cell proliferation and dedifferentiation than SAP or Free-drug alone, and thus reduced chronic renal fibrosis in I/R mice. This study highlighted that SAP could sequentially deliver the two drugs to achieve anti-inflammatory and pro-proliferative effects with one injection and thus is a promising delivery platform for tissue repair. STATEMENT OF SIGNIFICANCE: Ischemia-reperfusion (I/R)-induced organ injury is a serious health issue, and delayed tissue repair leads to chronic fibrosis and organ failure. Systemic administration of anti-inflammatory agents or growth factors have shown some benefits on I/R injury, but their therapeutic efficacy was limited by side effects, poor bioavailability, and absent key signals of tissue repair. To address these issues, a hydrogel-based drug co-delivery platform was used to treat I/R injury. This platform could achieve sequential release kinetics with faster rate of anti-TNF-ɑ and slower rate of HGF, and effectively promoted tissue repair by targeting inflammation and proliferation in mice with renal I/R. This nanoscale delivery platform represents a promising strategy for solid organs (heart, liver and kidney) regeneration after I/R.

Glatiramer acetate attenuates renal ischemia reperfusion injury in rat model

Chronic renal failure can ultimately lead to kidney transplantation. Renal transplantation is associated with ischemia-reperfusion injury (I/R).² The subsequent processes of kidney I/R can lead to irreversible damages to the kidney tissue. Glatiramer acetate is an immunomodulatory drug for the treatment of multiple sclerosis (MS) and the anti-inflammatory effects of this drug have already been proven in some inflammatory models. The purpose of this study was to evaluate the protective effects of Glatiramer on reducing the damages arising from kidney ischemia-reperfusion. In this study, 35 Wistar rats were used which divided into 5 groups: sham, control (I/R), I/R + Glatiramer 0.5 mg/kg, I/R + Glatiramer 1 mg/kg, I/R + Glatiramer 2 mg/kg. Renal arteries were clamped bilaterally for 45 min, then the clamps were removed and the reperfusion process continued to 24 h. In the following, serum and kidneys were separated for analysis. In the control group, serum levels of LDH, inflammatory factor TNF-α and renal functional markers such as BUN and Creatinine were remarkably increased, but in the treatment groups, especially in Glatiramer 2 mg/kg received group, a significant decrease in these factors was observed. Tissue concentration of MDA was reduced following Glatiramer treatment. Besides, Glatiramer attenuated the increased kidney level of NF-κB protein using immunohistochemical assay. NFkB migration to the nucleolus increases inflammatory cytokines production. The anti-inflammatory factor, IL-10, in serum was significantly increased in the treatment group of Glatiramer 2 mg/kg. Furthermore, Glatiramer decreased renal tissue injury score according to the histopathological study. These results demonstrate that Glatiramer may play protective effects in kidney ischemia-reperfusion injury by reducing inflammatory and oxidative damages.

Dendritic Cells as Sensors, Mediators, and Regulators of Ischemic Injury

Dendritic cells (DCs) are highly specialized, bone marrow (BM)-derived antigen-processing and -presenting cells crucial to the induction, integration and regulation of innate, and adaptive immunity. They are stimulated by damage-associated molecular patterns (DAMPS) via pattern recognition receptors to promote inflammation and initiate immune responses. In addition to residing within the parenchyma of all organs as part of the heterogeneous mononuclear phagocyte system, DCs are an abundant component of the inflammatory cell infiltrate that appears in response to ischemia reperfusion injury (IRI). They can play disparate roles in the pathogenesis of IRI since their selective depletion has been found to be protective, deleterious, or of no benefit in mouse models of IRI. In addition, administration of DC generated and manipulated ex vivo can protect organs from IRI by suppressing inflammatory cytokine production, limiting the capacity of DCs to activate NKT cells, or enhancing regulatory T cell function. Few studies however have investigated specific signal transduction mechanisms underlying DC function and how these affect IRI. Here, we address current knowledge of the role of DCs in regulation of IRI, current gaps in understanding and prospects for innovative therapeutic intervention at the biological and pharmacological levels.

Catechin ameliorates Porphyromonas gingivalis-induced inflammation via the regulation of TLR2/4 and inflammasome signaling

BACKGROUND

Porphyromonas gingivalis is a major periodontopathogen found in patients with chronic periodontitis that can lead to alveolar bone or tooth loss. Interleukin-1β (IL-1β), a proinflammatory cytokine, is most relevant to the pathogenesis of periodontitis. Catechin is one of the main polyphenol compounds found in green tea and possesses a range of health benefits. This study examined the anti-inflammatory effects of catechin in THP-1-derived macrophages infected with P. gingivalis as well as its effects on P. gingivalis-induced periodontitis in a mouse model.

METHODS

The cytokine levels and relevant protein expression in THP-1 cells were measured using an enzyme-linked immunosorbent assay and Western blot analysis, respectively. An apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) pyroptosome formation was measured by confocal laser scanning microscopy. Micro-computed tomography was used to determine the level of bone loss induced by a P. gingivalis oral infection.

RESULTS

Catechin attenuated the production of IL-1β by inhibiting pro-IL-1β expression via the downregulation of nuclear factor-κB, p38 mitogen-activated protein kinase, and Toll-like receptor signaling. In addition, catechin inhibited the activation of inflammasomes induced by P. gingivalis, but did not affect the growth of P. gingivalis. Catechin reduced the level of alveolar bone loss in a P. gingivalis-induced periodontitis mouse model.

CONCLUSION

Catechin possesses anti-inflammatory properties by reducing the level of IL-1β production, suggesting that it can potentially be used for the prevention and treatment of periodontal inflammation caused by P. gingivalis.

High TNF-α and/or p38MAPK expression predicts a favourable prognosis in patients with T1N0M0 hepatocellular carcinoma: An immunohistochemical study

Tumour necrosis factor α (TNF-α) and p38 mitogen-activated protein kinase (p38MAPK) serve an important role in regulating tumour cell apoptosis. However, a limited number of studies have investigated the predictive value of both TNF-α and p38MAPK in hepatocellular carcinoma (HCC). An integrated bioinformatics analysis was initially performed using two datasets available from the Oncomine™ database to determine the association between TNF-α and/or p38MAPK expression and prognosis of patients with HCC. Subsequently, TNF-α and p38MAPK expression in tissue samples from 83 patients with HCC classified as T1N0M0, using the Tumour-Node-Metastasis (TNM) staging system, was investigated using immunohistochemistry. The associations between clinicopathological characteristics and different TNF-α and p38MAPK expression levels in HCC were investigated using the χ2 test. Kaplan-Meier and Cox univariate/multivariate survival analyses were performed to explore the predictive significance of TNF-α and/or p38MAPK expression in patients with HCC. Using the Oncomine™ database, it was revealed that TNF-α and/or p38MAPK expression was not significantly associated with overall survival (OS) or disease-free survival (DFS) rates; however, TNF-α and p38MAPK expression levels were positively associated (P<0.05), and high p38MAPK expression was significantly associated with low aspartate aminotransferase levels (P<0.05). Compared with low expression levels of TNF-α and p38MAPK together, high expression of TNF-α alone, p38MAPK alone and TNF-α and p38MAPK together were significantly associated with improved OS and DFS rates (P<0.05). Additionally, multivariate Cox regression models suggested that high expression levels of TNF-α alone, p38MAPK alone, or TNF-α and p38MAPK together in the HCC microenvironment were independent predictive factors for OS and DFS rates (P<0.05). Patients with T1N0M0 HCC with high TNF-α and/or p38MAPK expression had a significantly lower risk of recurrence and mortality compared with patients with low TNF-α and p38MAPK expression. Consequently, TNF-α and p38MAPK could serve as predictive biomarkers or potential therapeutic targets for T1N0M0 HCC treatment.

Protective Effect of Hesperidin on Sodium Arsenite-Induced Nephrotoxicity and Hepatotoxicity in Rats

The present study was conducted to investigate the protective effects of hesperidin (HSP) against sodium arsenite (SA)-induced nephrotoxicity and hepatotoxicity in rats. Thirty-five male Sprague Dawley rats were divided into five groups as follows: control, HSP, SA, SA + HSP 100, and SA + HSP 200. Rats were orally gavaged with SA (10 mg/kg body weight) and HSP (100 and 200 mg/kg body weight) for 15 days. SA increased oxidative damage by decreasing antioxidant enzyme activities, such as catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx), and glutathione (GSH) level and increasing malondialdehyde (MDA) level in the kidney and liver tissues. In addition, it increased serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities and serum urea and creatinine levels. Furthermore, SA caused inflammation, apoptosis, and oxidative DNA damage by increasing tumor necrosis factor-α (TNF-α), nuclear factor kappa B (NF-κB), interleukin-1β (IL-1β), cysteine aspartate-specific protease-3 (caspase-3), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels in the kidney and liver tissues and by increasing liver p53 and kidney interleukin-6 (IL-6) expressions. In other words, HSP administration reduced apoptosis, oxidative stress, inflammation, and oxidative DNA damage significantly in SA-induced kidney and liver tissues depending on dose. In this study, it was seen that HSP showed a protective effect against SA-induced kidney and liver toxicity.

Xenogeneic Transplantation of Human Placenta-Derived Mesenchymal Stem Cells Alleviates Renal Injury and Reduces Inflammation in a Mouse Model of Lupus Nephritis

Human placenta-derived mesenchymal stem cells (pMSCs) are considered a good source for cell therapy. The purpose of this study was to observe whether the transplantation of human pMSCs would affect the treatment of lupus nephritis (LN)-prone MRL/lpr mice. Multiple injections (at the 16th, 18th, and 20th week of age) of 1 × 106 pMSCs were administered. Urine was collected to evaluate proteinuria and urine creatinine levels. Blood was collected for the measurement of serum antinuclear antibody (ANA) and anti-double-stranded DNA (dsDNA) antibody levels. Renal tissues were collected for histological staining and examination by light and electron microscopy quantitative reverse transcription polymerase chain reaction (RT-qPCR) and Western Blot. The results confirmed that pMSC treatment reduced the severity of 24-h proteinuria, decreased the production of anti-dsDNA antibodies, and ameliorated renal pathological changes in MRL/lpr mice. Furthermore, pMSCs reduced renal inflammation by inhibiting the expression of nuclear factor kappa B (NF-κB) and then downregulating the expression of tumor necrosis factor-α (TNF-α), intercellular cell adhesion molecule-1 (ICAM-1), and plasminogen activator inhibitor-1 (PAI-1). Therefore, our present study demonstrated a protective effect of pMSCs against renal injury and inflammation in MRL/lpr mice.

Fimasartan attenuates renal ischemia-reperfusion injury by modulating inflammation-related apoptosis

Fimasartan, a new angiotensin II receptor antagonist, reduces myocyte damage and stabilizes atherosclerotic plaque through its anti-inflammatory effect in animal studies. We investigated the protective effects of pretreatment with fimasartan on ischemia-reperfusion injury (IRI) in a mouse model of ischemic renal damage. C57BL/6 mice were pretreated with or without 5 (IR-F5) or 10 (IR-F10) mg/kg/day fimasartan for 3 days. Renal ischemia was induced by clamping bilateral renal vascular pedicles for 30 min. Histology, pro-inflammatory cytokines, and apoptosis assays were evaluated 24 h after IRI. Compared to the untreated group, blood urea nitrogen and serum creatinine levels were significantly lower in the IR-F10 group. IR-F10 kidneys showed less tubular necrosis and interstitial fibrosis than untreated kidneys. The expression of F4/80, a macrophage infiltration marker, and tumor necrosis factor (TNF)-α, decreased in the IR-F10 group. High-dose fimasartan treatment attenuated the upregulation of TNF-α, interleukin (IL)-1β, and IL-6 in ischemic kidneys. Fewer TUNEL positive cells were observed in IR-F10 compared to control mice. Fimasartan caused a significant decrease in caspase-3 activity and the level of Bax, and increased the Bcl-2 level. Fimasartan preserved renal function and tubular architecture from IRI in a mouse ischemic renal injury model. Fimasartan also attenuated upregulation of inflammatory cytokines and decreased apoptosis of renal tubular cells. Our results suggest that fimasartan inhibited the process of tubular injury by preventing apoptosis induced by the inflammatory pathway.

Anti-inflammatory and protective effects of saffron extract in ischaemia/reperfusion-induced acute kidney injury

AIM

Inflammation is one of the major challenges in the management of ischaemia/reperfusion (I/R)-induced acute kidney injury. Our aim was to assess the anti-inflammatory and protective effects of saffron extract against I/R-induced renal disturbances.

METHODS

A total of 35 male Wistar rats were randomly divided into five groups (n = 7) as sham, I/R and three groups of I/R that were pretreated with different doses of saffron extract (5 mg/kg, 10 mg/kg, or 20 mg/kg) intraperitoneally. The I/R-induced renal inflammation was assessed by measuring leukocyte infiltration and mRNA expression levels of intercellular adhesion molecule-1 and tumour necrotic factor-alpha. For the assessment of oxidative stress, thiobarbituric acid reactive species and antioxidant capacity of kidneys were measured in the right kidneys. In addition, plasma creatinine and urea-nitrogen concentrations were determined for renal functional disturbances. Statistical analysis was performed using one-way analysis of variance using the Duncan post hoc test.

RESULTS

The I/R increased all of the measured parameters, except for the tissue level of ferric reducing/antioxidant power, which decreased. Pretreatment with saffron extract in all doses significantly reduced the severity of these disturbances in such a way that there were no significant differences between the FRAP level and urea-nitrogen concentrations between the sham and all three saffron extract-treated groups. However, the saffron extract could decrease the plasma creatinine concentration, malondialdehyde level, tumour necrotic factor-alpha and intercellular adhesion molecule-1 expression and leukocyte infiltration in a dose-dependent manner.

CONCLUSION

The present study showed anti-inflammatory, anti-oxidative and protective effects for the hydro-ethanolic extract of saffron in I/R-induced acute kidney injury.

Diosmin and crocin alleviate nephropathy in metabolic syndrome rat model: Effect on oxidative stress and low grade inflammation

Nephropathy is a serious complication of metabolic syndrome (MS), a global epidemic disorder. This study was undertaken to investigate the actions of diosmin and crocin, two natural ingredients, on diabetic nephropathy in a rat model of MS and the underlying mechanism(s). Metabolic syndrome was induced by the addition of 10% fructose to drinking water and placing the rats on high-salt diet for 16 weeks. Diosmin and Crocin were orally administrated daily for 10 weeks starting at week 6. At the end of study, arterial blood pressure was non-invasively recorded. Urine, serum and kidneys were collected for renal function, oxidative stress, glycemic parameters, inflammatory markers and histological analysis. Both Diosmin and Crocin improved insulin resistance, decreased blood pressure, uric acid, lipoproteins and blocked diabetic nephropathy as indicated by reduction of albumin excretion rate and albumin/creatinine ratio. They alleviated the impaired filtration in MS as indicated by increased creatinine clearance. They also ameliorated oxidative stress and the low-grade 1inflammation as indicated by reduction of serum TNF-α and inflammatory cells. These observations suggest that both Diosmin and Crocin alleviate metabolic syndrome and the associated nephropathy in rats, possibly, through inhibiting oxidative stress and inflammation.

Ischemic acute kidney injury and klotho in renal transplantation

Post-transplant ischemic acute kidney injury (AKI), secondary to ischemia reperfusion injury (IRI), is a major problem influencing on the short and long term graft and patient survival. Many molecular and cellular modifications are observed during IRI, for example, tissue damage result production of reactive oxygen species (ROS), cytokines, chemokines, and leukocytes recruitment which are activated by NF-κB (nuclear factor kappa B) signaling pathway. Therefore, inhibiting these processes can significantly protect renal parenchyma from tissue damage. Klotho protein, mainly produced in distal convoluted tubules (DCT), is an anti-senescence protein. There is increasing evidence to confirm a relationship between Klotho levels and renal allograft function. Many studies have also demonstrated that expression of the Klotho gene would be down regulated with IRI, so it will be used as an early biomarker for acute kidney injury after renal transplantation. Other studies suggest that Klotho may have a renoprotective effect for attenuating of kidney injury. In this review, we will discuss pathophysiology of IRI-induced acute kidney injury and its relation with klotho level in renal transplantation procedure.

Anti-inflammatory Effects of Valproic Acid in a Rat Model of Renal Ischemia/Reperfusion Injury: Alteration in Cytokine Profile

Valporic acid (VPA) has been implicated to have anti-inflammatory and anti-oxidant activities in several ischemic/reperfusion (I/R) injury models. This study intended to evaluate whether VPA could affect the inflammatory/anti-inflammatory cytokines balance and severity of renal I/R injury in rat. I/R injury was induced in two groups of animals, vehicle normal saline and VPA-treated (IP injection, 150 mg/kg) rats, by 45 min occlusion of both left and right renal arteries followed by 3, 24 and 120 h reperfusion in separate groups. After each time point, kidneys and blood samples were collected for cytokine genes (TNF-α, IL-1β, IL-10 and TGF-β) expression analysis and histological examinations in the kidney tissues. Serum creatinine levels were measured for evaluation of renal function. We observed significantly downregulated mRNA expressions for IL-1β and TNF-α in blood and tissue samples 24 and 120 h post I/R injury in VPA-treated animals compared to control groups (P < 0.0001). On the other hand, mRNA expression levels for IL-10 and TGF-β were significantly increased in the blood samples from VPA-treated animals at two time points after I/R injury (P < 0.0001) and at 120 h in tissue samples (P < 0.001). Histopathology analysis showed downgraded ischemic changes in VPA group compared to sham control. Also, decreased serum creatinine levels were observed in VPA-treated animals particularly 120 h post I/R injury (P < 0.0001) that was correlated with less pathological changes in this group. Our results indicate that VPA can attenuate pro-inflammatory responses and augment the anti-inflammatory condition in favor of faster renal recovery from ischemic changes and improved renal function after renal I/R injury.

Effects of a Single Dose of Parecoxib on Inflammatory Response and Ischemic Tubular Injury Caused by Hemorrhagic Shock in Rats

Parecoxib, a selective COX-2 inhibitor, is used to improve analgesia in postoperative procedures. Here we evaluated whether pretreatment with a single dose of parecoxib affects the function, cell injury, and inflammatory response of the kidney of rats subjected to acute hemorrhage. Inflammatory response was determined according to serum and renal tissue cytokine levels (IL-1α, IL-1β, IL-6, IL-10, and TNF-α). Forty-four adult Wistar rats anesthetized with sevoflurane were randomized into four groups: placebo/no hemorrhage (Plc/NH); parecoxib/no hemorrhage (Pcx/NH); placebo/hemorrhage (Plc/H); and parecoxib/hemorrhage (Pcx/H). Pcx groups received a single dose of intravenous parecoxib while Plc groups received a single dose of placebo (isotonic saline). Animals in hemorrhage groups underwent bleeding of 30% of blood volume. Renal function and renal histology were then evaluated. Plc/H showed the highest serum levels of cytokines, suggesting that pretreatment with parecoxib reduced the inflammatory response in rats subjected to hemorrhage. No difference in tissue cytokine levels between groups was observed. Plc/H showed higher percentage of tubular dilation and degeneration, indicating that parecoxib inhibited tubular injury resulting from renal hypoperfusion. Our findings indicate that pretreatment with a single dose of parecoxib reduced the inflammatory response and tubular renal injury without altering renal function in rats undergoing acute hemorrhage.

Renoprotective effects of montelukast in an experimental model of cisplatin nephrotoxicity in rats

Renal toxicity is one of the most severe complications that can occur with cisplatin (CIS) administration in cancer patients. Montelukast (ML) renoprotective outcome contrary to CIS-drawn nephrotoxicity remains obscure. Therefore, adult male Sprague-Dawley rats were orally given ML (10 and 20 mg/kg/day) 5 days before and after single CIS (5 mg/kg; i.p.) treatment. ML returned blood urea nitrogen, as well as serum creatinine and gamma glutamyl transferase that were elevated by CIS to normal level. The improved kidney function tests corroborated the attenuation of CIS renal injury at the microscopical level. It also reduced serum/renal nitric oxide and renal hemeoxygenase-1. Meanwhile, ML hindered the raised levels of serum endothelin-1, serum and renal tumor necrosis factor-α, and monocyte chemoattractant protein-1. These effects were associated by deceased caspase-3 expression in kidney after ML treatment. In conclusion, ML guards against CIS-induced nephrotoxicity via anti-inflammatory and antiapoptotic properties.

Protective effect of Malva sylvestris L. extract in ischemia-reperfusion induced acute kidney and remote liver injury

Mallow (Malva sylvestris L.) has had medicinal and therapeutic uses in addition to its oral consumption. The present study was conducted to examine the protective effect of Malva sylvestris L. extract on ischemia-reperfusion-induced kidney injury and remote organ injuries in the liver. Before ischemia-reperfusion, rats in the different groups received intraperitoneal normal saline or mallow extract at the doses of 200, 400 or 600 mg/kg of body weight. After 30-minutes of bilateral renal ischemia followed by 24-hours of reperfusion, tissue damage in the kidney and liver samples were determined through studying H&E-stained slides under a light microscope. The degree of leukocyte infiltration and tissue mRNA expressions of TNF- and ICAM-1 were then measured to examine the degree of renal inflammation. The renal tissue MDA and FRAP levels were measured for determining the amount of oxidative stress. Plasma concentrations of creatinine, urea, ALT and ALP were also measured. Ischemia-reperfusion led to a significant increase in plasma concentrations of creatinine, urea, ALT and ALP, and renal tissue MDA, and a significant decrease in renal tissue FRAP. The expression of pro-inflammatory factors in the kidney tissue, the level of leukocyte infiltration and the amount of tissue damage in the kidney and liver also increased. Pretreatment by mallow extract led to a significant improvement in all the variables measured. The 200- and 400-mg doses yielded better results in most parameters compared to the 600-mg dose. The findings showed that mallow extract protects the kidney against ischemia-reperfusion and reduces remote organ injury in the liver.

Urinary excretion of EGF and MCP-1 in children with vesicoureteral reflux

Purpose

The aim of this study was to investigate the urinary concentration of epidermal growth factor (EGF) and monocyte chemotactic protein-1 (MCP-1) as reflux nephropathy (RN) biomarkers before and after endoscopic treatment of moderate to severe vesico-ureteral reflux (VUR).

Materials and methods

A prospective study was carried out on 72 children with moderate to severe VUR. All patients underwent endoscopic treatment using Macroplastique® or Deflux®. Vesico-ureteral reflux resolution was tested by post-operative voiding cystourethrography after 3 months and 2 years. Follow-up urinary samples were collected at that time. Control samples were taken from healthy children with no clinical evidence of renal and bladder disease and no history of UTI.

Results

In VUR patients, pre-operative urinary EGF levels had a down-regulation when compared to controls. Following successful VUR repair, urinary EGF levels of VUR children progressively increased only at long term follow-up but without returning to normal levels. Urinary MCP-1 levels were highly expressed in pre-operative samples and decreased markedly during early post-operative measurements. Urinary MCP-1 levels did not further decreased in late post-operative follow-up. In fact, these levels remained significantly higher when compared to controls.

Conclusions

Urinary levels of EGF and MCP-1 may become useful markers for monitoring the response to surgical treatment in VUR patients. Although endoscopic VUR treatment is effective in reducing the inflammatory response, the persistence of significant abnormal levels of inflammatory cytokines (such as urinary MCP-1) at long term follow-up suggests that surgery alone may not completely treat the chronic renal inflammation evidenced in these children.

The transfection of A20 gene prevents kidney from ischemia reperfusion injury in rats

Ischemia/reperfusion may induce inflammation and cell death through the nuclear factor (NF)‑κB signaling pathway. As a negative regulator of NF‑κB, zinc finger A20 exhibits anti-apoptotic and anti‑inflammatory effects in vitro. The present study was designed to upregulate A20 expression using an A20 transfection approach to investigate the in vivo protective effects of the A20 gene on renal ischemia reperfusion injury. The A20 gene was cloned into a pcDNA3.1 vector to construct the expression plasmid pcDNA3.1‑A20. The plasmid was wrapped with a liposome and injected intravenously into rats 48 h prior to establishing the models of renal ischemia reperfusion injury. Saline and the empty plasmid pcDNA3.1 were used as controls. Following 24 h post‑operation, A20 expression was determined using reverse transcription‑quantitative polymerase chain reaction and western blotting. The renal function and structure were assessed by analyzing the concentrations of serum creatinine (Scr), blood urea nitrogen (BUN) and histological features. Renal tissues were additionally examined for renal tubular cell apoptosis and NF‑κB activity. The results demonstrated that in vivo transfection of pcDNA3.1‑A20 induced renal A20 expression in rats. A20 overexpression in vivo significantly reduced renal injury as demonstrated by the improved levels of Scr and BUN and the reduction in histological damage. These improvements were accompanied by a suppression of renal proximal tubular epithelial cell apoptosis and an inhibition of NF‑κB activity. These results indicated that transfection of the A20 gene upregulates the expression of A20 in vivo and protects the kidneys from ischemia reperfusion injury via inhibition of the NF‑κB signal transduction pathway.

Evaluation of Caspase 3 Enzyme and TNF-alpha as Biomarkers in Ureteropelvic Junction Obstruction in Children- a preliminary report

OBJECTIVE

To determine the applicability of urinary caspase 3 enzyme and TNF-α as biomarkers in children with ureteropelvic junction obstruction (UPJO).

METHODS

In this study, 31 unilateral UPJO patients and 33 age- and sex-matched healthy childrens were enrolled. The patients with UPJO consisted of 11 female and 20 male children between the ages of 2 to 62 months old. All participants were evaluated regarding anterior-posterior(AP) diameter and cortical thickness of affected kidney by ultrasonography. Technetium DTPA renal scan and voiding cystourethrogram(to assess vesicoureteral reflux) were performed, pre-operatively. Also, urinary levels of TNF-α and caspase 3 enzyme were checked. Follow-ups included measurement of aforementioned indices in patients: AP diameter and cortical thickness of the affected kidney, as well as TNF-α and caspase 3 levels in urine, three and six months after pyeloplasty.

RESULTS

The results showed highly significant decrease in urinary TNF-α and caspase 3 enzyme (P values < 0.01), approaching the level measured in children without UPJO after six months. Significant decrease in AP diameter and increase in cortical thickness were also noticed (P values < 0.01).

CONCLUSION

The results of this study strongly support that TNF-α and caspase 3 levels in urine can be used for improvement monitoring in follow-up of UPJO patients after pyeloplasty and can also be potentially used as determining indices for surgical plan but more studies, especially in patients who are not surgical candidates are needed to confirm our observaitons.

Protective impact of resveratrol in experimental rat model of hyperoxaluria

PURPOSE

Resveratrol (RES) is a polyphenol with antioxidant, anti-inflammatory, and many other physiological effects on tissues. In the present study, the effect of resveratrol in hyperoxaluria driven nephrolithiasis/nephrocalcinosis is investigated.

METHODS

Wistar-Albino rats of 250-300 g (male, n = 24) were included in the present study. The rats were randomized into three groups: Group 1 consisted of the controls (n = 8), Group 2 of hyperoxaluria (1% ethylene glycol (EG), n = 8), and Group 3 of the treatment (1% EG + 10 mg/kg of RES, n = 8) group. At the beginning and fifth week of the study, two rats from each group were placed in metabolic cages for 24 h and their urine was collected. At the end of the study, the rats were killed and their blood was collected from the vena cava inferior. The right kidneys of the rats were used for biochemical and the left ones for immunohistochemical analyzes. Malondialdehyde (MDA), catalase, urea, calcium, oxalate, and creatinine clearance were studied in the blood, urine, and kidney tissues. Moreover, routine histological evaluation, and p38-MAPK and NFkB immunohistochemical analyses were conducted.

RESULTS

In the hyperoxaluria group, urinary oxalate levels were higher than the control group; yet, lower in the treatment group compared to hyperoxaluria group (p < 0.05). Serum MDA levels in the hyperoxaluria group were higher than the control group; but in the treatment group it is lower than the hyperoxaluria group (p < 0.05). P38 MAPK activity was higher in the hyperoxaluria group compared to the control (p < 0.05). However, in terms of p38 MAPK activity, there were no statistically significant difference between hyperoxaluria and the treatment group (p < 0.069). Whereas NFkB activity in the hyperoxaluria group is higher than the control (p < 0.001), no statistically significant difference was observed with the treatment group.

CONCLUSIONS

In the present study, resveratrol was seen to prevent hyperoxaluria. With preventing oxidative stress factors and Randall plaque formation caused by free oxygen radicals, resveratrol can be an alternative treatment option that can increase the success rate in preventing stone recurrence in the future.

Optimising renal cancer patients for nephron-sparing surgery: a review of pre-operative considerations and peri-operative techniques for partial nephrectomy

Nonmodifiable factors including pre-operative renal function and amount of healthy renal tissue preserved are the most important predictive factors that determine renal function after partial nephrectomy. Ischaemia time is an important modifiable risk factor and cold ischaemia time should be used if longer ischaemia time is anticipated. New techniques may have a role in maximising postoperative kidney function, but more robust studies are required to understand their potential benefits and risks.